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Self Interest and Social Behavior/Aims and Objectives

We would like to view social behavior as scientists and seek any "natural laws" that determine this behavior. Models of self-interest offer one candidate for such laws. These models are relatively simple, powerful in their predictions, and might apply to all social behavior.

While we do examine both strengths and weaknesses of these models, we leave it to others to provide detailed empirical support or refutation of these models in these applications, but we do intend to demonstrate that these hypotheses should, at a minimum, be considered seriously because of their simplicity, their power, and their potentially wide scope.

As we construct these models, we also illustrate the process of building models of social behavior. You will see how our predictions and our level of understanding change when we alter our assumptions, when we make seemingly innocuous changes to the feasible choices available, and when we focus on different characteristics that we expect to occur in equilibria. We hope that this experience improves your judgment when you create and modify models of social behavior or at least when you criticize (constructively, of course) models that others create.

Our Objectives
We have 3 primary objectives:
 * 1) Develop skills in models of self-interest: decision theory and game theory
 * 2) Learn through real applications throughout the social sciences
 * 3) Be accessible to undergraduates and general readers

Develop skills in models of self interest: decision theory and game theory
Our first objective for this course is to introduce you to models of self-interest, that is, those based upon the mathematics of decision theory and game theory, and to allow you to develop skill with these models and their use for predicting and explaining social behavior. Social behavior, in general, involves actions taken by individuals that, at least when aggregated over a group, affect other individuals. We want to predict and explain this behavior. Viewing this as scientists, we would like to discover, in effect, any “natural laws” that determine this behavior, if not for all environments then for some. As with any scientific search for natural laws, science takes any candidates for such natural laws and their associated models of behavior, however obtained, determines consequences that must occur if they are to hold, and ultimately tests these predicted consequences against experience. This process is continually repeated with new candidates for natural laws, candidates that now come from incremental modifications of the best performing models and occasionally from models based upon a new approach. Over time, we find potential natural laws and models that predict and explain actual experience better than the alternatives. Thus, at least eventually, we find more accurate predictions and more powerful explanations, those which are simpler or applicable to a wider variety of environments. If almost all practitioners conclude that such a set of natural laws and their associated model is more successful than other candidates, and they adopt it as their best explanation for the phenomena under study, then this model would offer a paradigm for their field.

One candidate for such a law of social behavior, one that may offer the foundation for a paradigm for each of the social sciences, is that individuals behave to further their own self-interest. Models of individuals furthering their own self-interest are formalized with either decision theory or game theory. Decision theory is the mathematics of optimizing behavior, where choices are made that further self-interest against an environment that does not change in response to these choices. In decision theory, each individual’s choices can be considered independently of choices that any other individual makes. It can be the foundation of either rational choice models or of evolutionary models. Game theory, building upon the foundation of decision theory, is the mathematics of strategic decisions, decisions where the value of the outcome to each individual depends upon the actions that other individuals take as well as actions that the decision maker takes herself. The rival’s choices may be influenced by the first individual’s choices. In game theory, an individual’s choices are interdependent with other individual’s choices. These "choices" might actually be rational choices that individuals make, or they may be the implicit "choices" that natural selection or cultural selection make, in that other alternatives become less frequent in later populations.

Learn through real applications throughout the social sciences
Our second objective for this course is to introduce you to these models of self-interested individuals through many of the actual applications that social scientists have actually wrestled with. We believe this is valuable for three reasons.

First, and most important, we conclude that a hypothesis that behavior is based upon self-interest should be considered seriously throughout the social sciences. In the tradition of a good liberal arts education that highlights the interconnections between various fields, this course centers on the use of common models within these many, varied fields. We introduce you to models of individuals furthering their own self-interest primarily through applications of these models over all areas of social behavior, whether the concern is competition versus cooperation; individuals acting alone or in alliances; or the use of money, sex, violence, or power. These models are applied to environments where individuals make rational choices, where natural selection favors the spread of the expression of some genes over others, or where cultural selection favors the spread of some ideas over others.

These applications come from the disciplines of economics, political science, psychology, biology, anthropology, and philosophy. Practitioners in these disciplines have adopted these models to varying degrees. These models provide the foundation of the current paradigm for two of these disciplines, economics and biology, and for two fields within two more disciplines, positive political economy within political science and evolutionary psychology within psychology. These models and modifications of them are the leading contenders in cognitive science within psychology and within behavioral economics. In other fields, these models remain controversial.

We especially introduce these models outside of those disciplines where they are not yet a core of their paradigms, not only because these models show us interconnections between disciplines, but also because any success in these new environments shows these models to be stronger. Data consistent with predictions from any model seen to apply over more environments are less likely to be due to chance or artifacts of a specific environment. Further, for those social sciences that do not now have models of self-interest as a core of their paradigms, great research opportunities exist transplanting well-known tools into new fields.

With each of these applications, we determine some of the predicted consequences from these models. We also describe briefly whether these consequences appear consistent or inconsistent with observations that others have made, but we largely leave the empirical testing to others with more expertise in these fields. We conclude that this hypothesis, that individuals further their own self-interest, yields predictions that appear consistent with actual social behavior within many environments; it is relatively simple, though more subtle than it might appear at first. We believe these models, or modifications of them, could apply to a tremendously wide scope of environments where social behavior occurs in all of them.

The focus on these models of self-interest that can provide a foundation for a paradigm that can be shared across all social behavior is a unique feature of this material over other courses or books on game theory or decision theory. Even though knowledge passes through disciplinary walls only with difficulty in almost all universities, especially through many of these disciplinary walls, we want the practitioners and students in all of these disciplines to see beyond their own walls and see the greater power these models have because of their tremendous scope. No other course or book covers the wide scope of social behavior that this material does.

Second, we believe that constructing useful mathematics as we see the need for it in these applications better motivates why this mathematics has been developed and why various concepts are important, which in turn, better motivates most students to consider these concepts in greater depth. The usual approach of constructing the mathematics and then illustrate the math with simplified, idealized "stick figure" applications leaves some students cold, especially students that have not yet developed an appreciation for the beauty or even the usefulness of mathematics. The richer applications do require more words, but in this situation, we feel that these additional words ease understanding. Presenting decision theory and game theory in this manner, developing richer applications first and the math as necessary, makes this course unusual but we hope this approach is more effective for you.

Third, we believe that considering this wide range of social behavior and the incremental construction of more sophisticated models will help you develop better judgment when considering what elements of an environment should be included within a model that you will find useful for your purposes. We take care to consider the effect of various assumptions, when it's useful to incorporate more elements of the environment within the model, and when its more useful to make knowingly false assumptions. Making good choices of what to include within a model requires good judgment.

Be accessible to undergraduates and general readers
Our third objective for this course is to make this material accessible to any undergraduate or general reader willing to examine social behavior through a mathematical prism, say at the level of a relatively mathematically adept sophomore. Our presentation primarily presumes some mathematical maturity, as we look at the world through these mathematical models, but not a great deal. As a test of this maturity and for some of the content, we presume the student has had a first calculus course; we do not presume any mathematical background beyond this one calculus course. To serve these students as well as the more advanced students, we intend to stress the intuition behind the questions, arguments, and conclusions, but without losing the rigor in any analysis considered for that application. In doing this, we do not present some questions, arguments, or conclusions in their most general form. We omit arguments or proofs that are not particularly insightful for the application. Some proofs we place in appendices. References should lead more advanced readers to any greater depth that they desire.

An Overview
We introduce you to these models of self-interest and their applications in four parts, roughly in order of their technical complexity. In each part, we apply the models developed across the social sciences, and depending upon the discipline these models may be applied to individuals making rational decisions, to natural selection favoring behavior that tends to follow with individuals having some particular DNA over other possibilities, to culture selection favoring behavior associated with some particular ideas over others, or to some combination of these mechanisms.

Decision Theory
Decision theory provides the framework for many important models throughout the social sciences, but we are primarily interested in many of its concepts and tools that we need for both decision theory and game theory. Decision theory provides an infrastructure for us to develop models based upon furthering one's self-interest. Preferences that are consistent or rational allow us to order feasible choices. We can express such choices as maximization problems: it's as if the individual makes a choice that maximizes the value of a "utility" function. We can even add uncertainty, further consistency requirements on our preferences, and describe that individual as maximizing his expected "utility."

The first part of our material introduces you to decision theory through applications in business, economics, political science, biology, and psychology. For some of these applications, we expect the individual to act as a rational decision maker, and we predict this outcome with our models. For others, we don't expect this exact mechanism to work, but we expect the individual to act as if he were a rational decision maker, while other elements of his environment, maybe the institutions in which he makes his choices or repeated experience, lead him to make these choices over time. We predict these outcomes with the same models. And for still other applications, a "dumb" evolutionary process is at work and over time an equilibrium is attained, and we can describe these outcomes too with these same models.

Static Games
Game theory provides a taxonomy for interdependent interactions based on self-interest. As with all good models, although such taxonomies may miss many crucial details in the particular application, they do capture basic strategic aspects of various situations, allowing us to better predict and explain outcomes for similar situations and to make linkages between applications. We intend to strengthen our common-sense intuition by starting with simple applications that we understand fairly well, and then in stages, consider slightly more complex environments with the same tools where our existing intuitions are less reliable. Over time, as we see enough applications, we strengthen our intuitions and ultimately understand these interdependent environments more deeply.

The second part of our material introduces you to static games, games in which all players choose their own strategies simultaneously. These are the simplest games, so they are the best place to learn some of the most important game-theoretic concepts, and they also provide the framework for what have been the most important contributions of game theory so far in its application. We consider all that is feasible when we define the game's strategic form, and then we predict outcomes to occur in equilibrium for such situations by the characteristics that we expect of any equilibria. We will consider applications to market power in economics, strategic voting in political science, fight or flight responses in biology, strategic international trade policy, and sexual strategies in biology.

Dynamic Games
The third part of this material introduces you to dynamic games with complete information and their applications. The language of games in their extensive form, which we compare and contrast with their strategic form, permits us to ask questions about the dynamics of games that allow individuals to take actions that are contingent upon previous actions taken by others. These more sophisticated strategies may allow more cooperation and more efficient outcomes than are possible without them. We consider applications to the common resource problem in economics, bargaining, collusion in economics, reciprocity in animal behavior, the development of cultural norms in small towns versus large cities, the development of ethics, incentives for firms to merge, and the coordination of behavior with communication.

Incomplete Information Games
The fourth part of this material introduces you to dynamic games with incomplete information and their applications. With incomplete information, a player does not know with certainty what game he is playing, but some players may have some proprietary information, generally about their own payoffs. With these games, a player may learn about his environment or about the characteristics of other players from actions that others take. Such possibilities also allow for the opportunity for individuals to reveal or disguise the actual environment to other individuals. With these games, we see moral hazard, adverse selection, and signaling in the context of insurance, education, and used cars.

A recurring thread throughout this material is determining when individuals following their self-interest is also in the interest of the group. In many situations, observers have seen what appear to be examples of altruism, the behavior of individuals that helps others but harms themselves. Are these examples of situations where models of self-interest fail? In what situations can self-interested individuals cooperate with each other for the greatest benefit for the group?

In some of these situations, the simplest model leads directly to efficient behavior, so that following individual self-interest is clearly mutually advantageous. In others, the simple model leads to inefficient behavior and enough cooperation for efficiency has not occurred. In these cases, we examine extensions of these models, usually creating a related dynamic game, and find six types of modifications that can lead to greater cooperation:

 * 1) kin selection — Individuals may sacrifice to help family members, but from the gene's point of view they are acting to promote this expression of the gene in later populations.
 * 2) Coasian bargaining — Individuals may choose to bargain and voluntarily accept income transfers that then modify their incentives enough to lead to an outcome that aids everyone.
 * 3) reciprocity — Individuals may choose to aid other individuals, even if it harms them in the short run, if they expect the recipients of this aid to reciprocate, and this swapping of favors may lead to an outcome that aids everyone.
 * 4) reputations — Individuals may be able to choose with whom they interact, and information is available that allows them to identify who has cooperated with others in the past, so that more individuals cooperate, yielding an outcome that aids everyone.
 * 5) relatively isolated sub-groups — In some situations, a general population splits into sub-groups and the success of these sub-groups depends upon this cooperation, so that when the general population re-forms more of the cooperators have survived.
 * 6) moral authority — Some individuals may promote the use of some behavioral rules that if followed would tend to lead to outcomes that aid everyone, offering their approval to individuals that follow them and their disapproval to those that don't, and the value of this approval or disapproval is enough for some individuals in some situations to follow these behavioral rules.

Ultimately, the behavior that we predict in these situations promotes the individual's self-interest, even though the behavior may look altruistic to an outside observer. These extensions show how additional cooperation can occur so that the group's interests are pushed as far as possible, but they are not based upon altruistic behavior.

Alternate Paths
The biggest drawback resulting from trying to both examine applications throughout the social sciences and make the discussion accessible to undergraduates is the greater length of exposition required. Even so, the reading tends to be easier (less dense) than most alternative presentations of decision theory and game theory, and no student is expected to cover every application in detail. Whatever your background beyond a first calculus course, you may pick a path of interesting applications through this material while still understanding the major insights that these models of self-interest provide. We mark particularly advanced sections with an asterisk. Once all of this material has been compiled, even after offering abridged versions of much of the best related literature for you, we find that covering all of the material here is not possible in a single undergraduate course. Nevertheless, this material offers several selective paths through it that remain coherent. If you are a social science student, one fruitful path is to focus on the basic tools plus applications in your discipline but only sample applications in the other disciplines. A non-social science student can fruitfully sample across the social sciences more evenly. To help you do choose applications more easily for the path that you choose, the following table indicates chapters or sections that deal with basic tools or applications in various disciplines.

 * TODO:Import and translate this table. --Whiteknight (talk) (projects) 22:34, 7 August 2006 (UTC)


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Self Interest and Social Behavior/Contributors

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History of Islam/Early Islam

The early history of Islam properly begins with Muhammad, an Arabian religious and political leader, who Muslims believe to be the last prophet of Allah (God). In Islamic historiography it is stated that Muhammad is a descendent of Ishmael, a son of Abraham.

Prophet Muhammad
Muhammad was born in 570 CE in the city of Mecca. As his father, Abdullah ibn Abdul-Muttalib, died shortly after marriage, his grandfather ‘Abd al-Muttalib became his guardian. ‘Abd al-Muttalib was the respected head of the clan of Hashim and the tribe of Quraysh, to which his clan belonged. With the Quraysh being the biggest and most influential tribe in Mecca, ‘Abd al-Muttalib was seen as the master of all of Mecca. The Quraysh had a special status in Mecca because they used to be in charge of the sacred Ka’ba. The Qur’an tells us that this holy edifice was built by Prophets Abraham and his son Ishmael:

(And when Abraham and Ishmael were raising the foundations of the House [Abraham prayed]: “Our Lord! Accept from us; surely You are the Hearing, the Knowing (2.127). Our Lord! Make us Muslims and raise from our offspring a nation of Muslims. Show us our ways of worship, and relent toward us. Surely, Your are the Relenting, the Merciful”) (2.128).

This means that the Ka’ba was built around 1900 BCE, which is when Abraham is thought to have lived. The Ka’ba maintained its venerable status as the destination of pilgrimage in the eyes of the pilgrims and the Arab population of the Arabian Peninsula down the centuries. ‘Abd al-Muttalib was personally in charge of the Ka’ba.

The Prophet was only about five to six years old when he lost his mother. Orphan Muhammad then lost his grandfather and custodian ‘Abd al-Muttalib at the age of eight. Now one of ‘Abd al-Muttalib’s sons, Abu Talib, became the guardian of his orphan nephew. Though respected by the clan of Hashim and the people of Mecca in general, Abu Talib did not possess the high status and influence of his father. Had he been more fortunate financially, he might have aspired to acquire that special leadership status.

When Muhammad was twenty five years old, he was hired by a woman called Khadija to take her merchandise to Syria. Khadija, a widow fifteen years Muhammad’s senior, later proposed marriage to him, which he agreed to. They lived together for almost a quarter of a century, until the death of Khadija about eight or nine years after the revelation of the Qur’an.

It is interesting to note that Muhammad did not marry any other woman during Khadija’s life, despite the fact that polygamy was common practice in that society. But after her death he took a number of wives. The exact number is not certain but it is believed that he had thirteen wives in all.

The Revelation
Muhammad was deeply interested in matters beyond this mundane life. He used to frequent a cave that became known as “Hira‘” on the Mountain of “Noor” (light) for contemplation. The cave itself, which survived the times, gives a very vivid image of Muhammad’s spiritual inclinations. Resting on the top of one of the mountains north of Mecca, the cave is completely isolated from the rest of the world. In fact, it is not easy to find at all even if one knew it existed. Once inside the cave, it is a total isolation. Nothing can be seen other than the clear, beautiful sky above and the many surrounding mountains. Very little of this world can be seen or heard from inside the cave. The inhabitant of that cave was obviously interested in things beyond this world and its material riches.

It was in that cave in 610 CE, i.e. at the age of forty, that Prophet Muhammad received from Allah the first verses of the Qur’an. Then and there, history changed.

The Qur’an continued to be revealed in fragments to Prophet Muhammad over the following twenty two years. The last words of the Book were revealed to the Prophet shortly before his death in 632 CE.

In the first two to three years after the revelation, the Prophet preached Islam secretly to individuals whom he trusted. When he started calling people to Islam publicly, the new religion gradually attracted more people but, not surprisingly, also increasing hostility from the idol worshipping population of Mecca. The Prophet was subjected to harassment and abuse. However, armed with patience, resilience, and determination, and protected by his uncle Abu Talib and the clan of Hashim, the Prophet was able to carry on preaching the new faith to people.

Converts to Islam, some of whom were slaves, had to suffer all kinds of persecution, including brutal torture and murder, at the hands of the enemies of the new religion in Mecca. In 614 CE, the Prophet had to instruct a group of Muslims to escape the persecution to Abyssinia and seek the protection of its just Christian king. The Quraysh then sent a delegation to the king, carrying precious gifts, to secure the extradition of the Muslim refugees. The king, however, rejected the bribe and let the Muslims stay in Abyssinia.

One year later, the Quraysh imposed economic and social sanctions on the Prophet, his followers, and his clan. As a result, the Muslims withdrew to a mountain in Mecca. The sanctions lasted about three years before collapsing in 618/619 CE without achieving their goals.

Soon afterward, the Prophet lost his wife Khadija. Matters got worse quickly with the death of his uncle and protector. Prophet Muhammad started to suffer more from the disbelievers’ relentless attempts to uproot Islam and destroy its followers. During the pilgrimage season in 622 CE, Muhammad met in Mecca with a number of chiefs from the city of Yathrib, where he had previously sent some Muslims to settle in. Having converted to Islam, the chiefs made a secret pledge to protect the Prophet should the Quraysh try to kill him.

However, the Quraysh learned about the agreement, so the people from Yathrib had to return quickly to their city. Sensing that the danger to Muslims has increased, Muhammad instructed them to immigrate individually or in small groups to Yathrib. The Qurayshites tried to prevent Muslims from fleeing Mecca to Yathrib, but the converts continued to sneak out gradually.

The continuing immigration of Muslims to Yathrib where they had allies was already very bad news for the Qurayshites. This could yet worsen were Muhammad also to move to that city. They decided that they had no other option but to kill him.

The various clans of the tribe of Quraysh agreed to act as one and assassinate the Prophet while asleep. The idea behind acting collectively was that no one party could be blamed for the killing and become embroiled in a war of vengeance with the clan of Hashim.

The assassination plan, however, was sabotaged by divine intervention. The night the murder was planned to take place, Allah informed His Prophet of the danger and ordered him to secretly leave Mecca and head to the city of Yathrib. The latter became known as “al-Madina al-Munawwara” (the illuminated city), or “al-Madina” for brief, after the arrival of the Prophet.

This famous event, known as the “Hijra ” (immigration), occurred in 622 CE, about twelve years after the revelation of the first verses of the Qur’an. This flight was destined to have far-reaching consequences in establishing the Islamic community, strengthening the position of Islam, and spreading its message.

The Prophet lived in al-Madina for about ten years. By the time of his departure from this world in 632 CE, Islam had become well established as the religion of the Arabian Peninsula and had made inroads in neighboring regions; Muslims had become a major force to be reckoned with in the area.

Abu Bakr
Was always a very close Companion of the Prophet, he knew him better than any other man. He knew how honest and upright the Prophet was. Such knowledge of the Prophet made Abu Bakr be the first man to follow the Message of Prophet Muhammad. He was indeed the first adult male to accept Islam.

The Prophet told Abu Bakr what had happened at Hira Cave, he told him that Allah had revealed to him and made him His Messenger. When Abu Bakr heard this from the Prophet, he did not stop to think, he at once became a Muslim. He submitted to Islam with such determination that once the Prophet himself remarked, "I called people to Islam, everybody thought over it, at least for a while, but this was not the case with Abu Bakr, the moment I put Islam before him, he accepted it without any hesitation." He was titled as-Siddiq by the Prophet because his faith was too strong to be shaken by anything.

In fact, Abu Bakr was more than a great believer, as soon as he became a Muslim, he immediately began to preach Islam to others. Among those who accepted Abu Bakr's invitation to Islam were 'Uthman, Az-Zubayr, Talhah, 'Abdur-Rahman ibn Awf, Sa'ad ibn Waqqas and others who later became component's of the prophet themselves.

Abu Bakr's love of the Prophet was so great that he was willing to sacrifice his life for the sake of protecting and comforting the Prophet saw. Such love and sacrifice were demonstrated when one day the Prophet was saying his prayers in the Ka'bah, while some of the chiefs of Makkah were sitting in the court yard of the Ka'bah. Seeing the Prophet praying, 'Uqbah ibn Abi Mu'it took a long piece of cloth and put it around the Prophet's neck and twisted it hard in an attempt to strangle the Prophet to death. At that moment Abu Bakr happened to pass by from a distance, he saw 'Uqbah trying to strangle the Prophet to death. Immediately Abu Bakr ran to the help of the Prophet, he pushed 'Uqbah aside and took the cloth from around the Prophet's neck. Thereupon the enemies of Islam came down upon Abu Bakr and beat him unmercifully, although Abu Bakr with faith like a rock did not care for his own suffering, he was glad that he was able to save the Prophet of Allah, even at the risk of his own life.

Abu Bakr with the wealth he had, also had a major role in freeing some of the Muslim slaves, who were barbarically tortured by their heartless masters to give up the faith and return to their masters' beliefs. The heartless monsters tried all kinds of torture: they made them lie all naked on the burning desert sand, putting big stones on their chest, as well as other kinds of torture. Here Abu Bakr's wealth came to the rescue, as he bought the poor helpless slaves from their inhuman masters and set them free, Bilal al-Habashi, the slave of 'Umayyah ibn Khalaf, was among those who were set free by Abu Bakr. Bilal became afterwards the mu'adhin at the Prophet's mosque.

Migration to Madinah
Islam was growing rapidly in Makkah, the enemies of Islam were getting frustrated by this rapid growth. The chiefs of Makkah found that it is necessary for them to get rid of the Prophet before Islam can cause a real threat to them, so they planned to kill the Prophet. Allah revealed to his Prophet the intentions of the non-believers and ordered him to migrate to Madinah. So the Prophet quickly went to Abu Bakr's house who was among the few that were left in Makkah with the majority of Muslims having already migrated to Madinah.

The Prophet informed Abu Bakr that he was commanded to migrate to Madinah that night and that he has chosen him to have the honor of joining him on his migration. Abu Bakr's heart was full of joy, "I have been looking forward to this day for months," he exclaimed.

The Makkans were so eager to find the Prophet they were searching for him like mad hounds. Once they came to the mouth of the cave, Abu Bakr grew pale with fright, he feared not for himself, but for the life of the Prophet. However, the Prophet remained calm and said to Abu Bakr, "do not fear, certainly Allah is with us". Such words quickly calmed down Abu Bakr and brought back tranquility to his heart.

Participation in Battles
Abu Bakr, being the closest of Companions to the Prophet, took part in all the battles that Prophet Muhammad had fought.

At 'Uhud and Hunayn, some members of the Muslim army showed signs of weakness, however, Abu Bakr's faith never wavered, he always stood like a rock by the side of the Prophet.

Abu Bakr's faith and determination to raise the banner of Islam were so great that at Badr, one of his sons, who had not yet embraced Islam was fighting among the enemies, Abu Bakr was so eager to find his son in the battle that he was searching for him amongst the enemies in order to slay him.

Abu Bakr's great love of the Prophet was demonstrated when peace talks at Hudaibiya were held. During the negotiations, the spokesman of Quraysh was touching the beard of the Prophet every now and then. Abu Bakr's love for the Prophet was so great that he could bear no more, he took out his sword and looked angrily at the man saying, " ... if that hand touches the beard of the Prophet again, it will not be allowed to go back."

Tabuk was the last expedition of the Holy Prophet. He was keen to make it a great success, he therefore asked people to help the expedition with whatever they could. This brought the best out of Abu Bakr who beat all records as he took all his money and household articles and heaped them at the Prophet's feet.

"Have you left anything for your children?" asked the Prophet. Abu Bakr then responded with great faith "Allah and his Messenger are enough for them." Companions standing around were stunned they realized that whatever they do they could not outdo Abu Bakr in the field of service to Islam.

The Successor of the Prophet
The Prophet Mohammed appointed Abu Bakr as his agent to lead the Hajj in place of him in the ninth year of Hijra.

The Prophet led the prayers himself ever since he arrived to Madinah. During his last illness, the Prophet could no longer lead the prayers, he was too weak to go to the mosque, he therefore had to choose someone to fill such high position after him. Abu Bakr was also the one who was honored to be chosen by the Prophet for such a task.

When the news of the Prophet's death came out, many Muslims were confused and stunned. 'Umar himself was so overcome with emotions that he drew his sword and declared, "If anyone says that the Messenger of Allah is dead, I will cut off his head."

Muslims stayed in such state until Abu Bakr arrived and gave his famous address:

"O People! If anyone among you worshipped Muhammad, let him know that Muhammad is dead. But those who worshipped Allah, let them know that He lives and will never die. Let all of us recall the words of the Qur'an. It says:

(Muhammad is only a Messenger of Allah, there have been Messengers before him. What then, will you turn back from Islam if he dies or is killed?)

Suddenly Abu Bakr's words started to sink in, and in no time confusion was gone.

Having shrugged off the shocking news of the Prophet's death, Muslims realized that they need someone to fill the position of leadership amongst them.

The two main groups amongst Muslims were Muhajirun (refugees from Makkah), and Ansar (the people of Madinah). The Ansar gathered at the Thaqifah Bani Saydah their meeting place. Sa'ad ibn Abadah, the Ansar leader, suggested that the Caliph should be from amongst them. Although many refused saying that the Muhajirun in right have a better claim to Khilafah. When the news reached Abu Bakr, he quickly went to their gathering, fearing that confusion might spread once again, and said, "Both Muhajirun and Ansar have done great service to Islam. But the former were the first to accept Islam, they were always very close to the Messenger of Allah. So, O Ansar, let the Caliph be from amongst them." After a short discussion, the Ansar agreed that they should choose the Caliph from amongst the Muhajirun, being from the tribe of Quraysh and being the first to accept Islam.

Abu Bakr then asked people to choose between 'Umar ibn al-Khattab and Abu 'Ubaydah ibn al-Jarrah. Hearing this, both men jumped to their feet and exclaimed "O Siddiq, how can that be? How can anyone else fill this position as long as you are among us? You are the top man amongst he Muhajirun. You were the Companion of the Prophet in the Thawr cave. You led prayers in his place, during his last illness. Prayer is the foremost thing in Islam. With all these qualifications you are the fittest person to be the successor of the Holy Prophet. Hold out your hand that we may pledge loyalty to you."

In the next day, Abu Bakr addressed the gathering of Muslims in the Prophet's mosque urging them to continue their path as true Muslims and to give him loyalty and support as long as he is obeying the Commands of Allah and His Messenger.

He was followed by Umar, Uthman ibn Affan and then Ali. These four are called the Rashidun caliphs which means The Righteous Caliphs. The word caliph means religious and spiritual leader. Under these caliphs Islam became one of the most important religions of the middle East. Administrative offices of the Muslim nation were established. Under Umar more then two thirds of the Eastern Roman Empire was conquered by the Muslims. Umar also started the Muslim calender.

The first civil war in Islam, also known as the First Fitna broke out in Islam during the rule of the fourth caliph Ali and lasted throughout his caliphate. The third caliph Uthman ibn Affan had been murdered by rebel Muslim groups who had political motives. After Ali took over, the most important problem he faced was that of punishing those responsible for murder. However many people felt that before accepting the position of the caliph, Ali should have focused his attention on finding and punishing the murderers. A group of people led by Muhammad's wife Aisha, her brothers in law Talhah and Zubair ibn al-Awam refused to recognize Ali's caliphate. They instead raised an army which met Ali's army at Basra in Iraq, originally for the purposes of negotiations. In the night, some fighting broke out, probably out of confusion or due to rebel groups who were involved in the infamous murder. This led to the Battle of Bassorah (also known as Battle of the Camel) in which Ali's party emerged victorious. Aisha was escorted back to Medina honorably after the battle by Ali.

This battle however did not entirely finish the tension in the Muslim empire. Ali was soon challenged by Muawiyah, the governor of the Muslim provinces of Syria. He too raised the issue of punishing Uthman's murderers and refused to acknowledge Ali as caliph until the issue had been solved. Muawiyah was a kinsman of Uthman and his army pledged to bring to justice the murderers and those who sheltered them. People who are sheltering the murderers was a reference to Ali and his followers. Accordingly, the two groups met and fought a battle, called the Battle of Siffin. This battle ended in a draw and so both groups decided on arbitration which also didn't lead to any concrete decision. Another group of Muslims, the Kharijites who had previously been with Ali, meanwhile rejected him because they felt that he was not following true Islam and conducting business over the caliphate as if it were his own property.

In the following years Ali's governors could not prevent his losing provinces to Muawiyah who increased his strength by further expanding his army. Ali had shifted the capital of the caliphate from Medina to Kufa in 656. He was killed by a Kharijite assassin in 661.

title: History of Islam/Early Islam


text:
Talk:Non-nerds Guide to Computers/Contents/motherboard

The flipping gender of the mail[wo]man sounds terrible. PC at its worst.


text:
User talk:Michael.j.sykora~enwikibooks

Please refer to my wikipedia account to message me. Cheers --Michael.j.sykora 01:40, 8 August 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Michael.j.sykora. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Michael.j.sykora~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:27, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:15, 19 April 2015 (UTC)

title: User talk:Michael.j.sykora~enwikibooks


text:
User:Michael.j.sykora~enwikibooks

Please refer to my wikipedia account, cheers. --Michael.j.sykora 01:41, 8 August 2006 (UTC)

title: User:Michael.j.sykora~enwikibooks


text:
Talk:Physics Textbook/Light

Name
From what I have see I like the book, but do you think that it's name should be changed to reflect the content? --Michael.j.sykora 01:45, 8 August 2006 (UTC)
 * I'd support a name change... the current name probably reflects a course number at a U.S. university. -- SB_Johnny | talk 10:31, 18 August 2006 (UTC)

title: Talk:Physics Textbook/Light


text:
Talk:X86 Assembly/NASM Syntax

The line "In some other operating systems other than Linux the arguments are pushed onto the stack rather than moved into registers." is ambigous, since function calls in GNU/Linux are passed on the stack, and only system calls are passed in registers. Also, I'd recommend an example than can be assembled and run. Thermostat 03:31, 8 August 2006 (UTC)

Line Removed
Removed: "Passing values to the registers in different orders won't affect the execution when the kernel is called, but deciding on a methodology can make it much easier to read."

Reasons: 1. it has nothing to do with NASM. 2. it states something utterly obvious. 3. it states something that applies to all OSes, not just Linux. 4. it is discussing best-practice for coding when this is not the article to do so.

Word size
Given that a lot of us are using 64-bit machines nowadays, maybe it would be wise to add a -m32 to some of the gcc command lines given in this page?

title: Talk:X86 Assembly/NASM Syntax


text:
User talk:Thermostat~enwikibooks

Hello! and welcome to wikibooks!

I've seen your comment on the x86 Assembly wikibook, and I wanted to personally thank you. We need all the help we can get on that book, and it is rare to find a contributer here that knows the subject. The x86 Assembly book was originally created by combining a number of smaller books and articles, some of which were poorly written to begin with. I have been slowing doing work to it myself, but I currently dont have any assemblers on my PC to use in writing example problems.

You are more then welcome to make any changes that you see fit, and I encourage you to contribute to this project more if you are able and willing. If you need anything at all, you can feel free to leave me a message on my talk page HERE. --Whiteknight (talk) (projects) 04:01, 8 August 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Thermostat. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Thermostat~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:49, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:35, 19 April 2015 (UTC)

title: User talk:Thermostat~enwikibooks


text:
Guitar/Tone and Volume

3 zones of distortion
The starting point for dialing-in various electric Rock guitar tone is not a crystal-clean full-range amplifier and speaker, but rather, a tube power amp pushing a guitar speaker that has limited frequency response, with the power tubes on the edge of breakup.

With power-tube distortion, and to a lesser extent with preamp tube distortion or solid-state distortion pedals, there are three zones: Clean, Compressed, and Distorted, somewhat corresponding to the terms Clean, Crunch or Rhythm, and Lead. The Clean zone ranges from literally clean with linear response, to the beginning of warmth and some smoothing and coloration. The Compressed zone ranges from slightly warm, smoothed, and colored, into slightly audible distortion. The Distorted zone runs from slight breakup to full distortion. Mathew laframboise

Controlling distortion voicing
An electric guitar has a volume control and tone control. The volume control almost always has a side-effect on equalization as you turn it down, affecting the pre-distortion equalization (EQ). The tone control reduces the amount of treble, affecting the pre-distortion EQ and thus the distortion voicing.

For increased control of the pre-distortion EQ, place an equalizer pedal in-between the guitar and the first distortion stage such as a distortion pedal or the guitar amp's built-in preamp. Switch between all the pickup settings, in conjunction with changing the distortion settings and EQ settings, to use the full range of basic sounds or "tones" the amp can produce.

The preamp Gain control on the distortion channel of the amp, or the Distortion control on a distortion pedal, sometimes has a side-effect of changing the equalization and thus the distortion voicing. In that case, you can use a lower distortion setting combined with a higher volume setting prior to the distortion stages, to dial-in a different distortion voicing with the same amount of distortion.

The tone stack on a standard tube amp is in-between the preamp distortion and the power-tube distortion. Thus the tone stack acts as the final part of shaping the preamp distortion voicing and also shapes the power-tube distortion voicing, together with the Master Volume control, which affects the amount of power-tube distortion voicing. For maximum power-tube distortion, set the tone controls and Master Volume to maximum, which is equivalent to bypassing them entirely.

When setting the preamp distortion, learn all the ways to adjust the equalization before the preamp distortion, including the guitar's volume and tone controls, a wah pedal, an equalization pedal, and any other volume or tone controls prior to the distortion stage. These affect the distortion voicing. More treble causes the treble to predominate in the complex clipping, resulting in a glassy liquid breakup tone; more bass prior to a distortion stage causes a dry, crusty breakup tone.

The same principles hold for controlling the power-tube distortion voicing. Learn all the ways to affect the equalization and level prior to the tube power amp, but after the preamp distortion.

Obtaining distortion independently of volume
To get power-tube distortion quietly or independently of volume level, use a power attenuator or an amplifier that has a built-in power attenuator, or a built-in power-supply based power attenuation (Power Scaling, Power Dampening, a Sag circuit, or a Variac).

It is possible to further voice the power-tube distortion by placing a dummy load (usually a power attenuator set entirely to use its built-in dummy load), an equalizer, and then a solid-state power amp between the power tubes and the guitar speaker.

A guitar speaker is a complex dynamic filter and transducer. Line-level cabinet simulators attempt to simulate this complex dynamic sound.

In the recording studio, the amp head and speaker cabinet are typically separated and the miked speaker cabinet is placed with microphones in a soundproofed isolation booth or in the live room. Either location is a soundproofed room separate from the control room where the mic signals return and the full-range monitor speakers reside for listening to the resulting power-tube distortion sound or loud quasi-clean amp sound at a controlled volume. In a home studio, the guitar speaker is sometimes placed in an isolation box with microphones.

Place one or two microphones near the guitar speaker. If you use two microphones, this causes some complex comb filtering; be prepared to swing the mixer's equalization for the two channels around very freely, because the effects of comb filtering are unpredictable. If you use a single microphone, setting the mixer's equalization is more straightforward.

title: Guitar/Tone and Volume


text:
Jet Propulsion/Propellants

Jet fuel which is a type of kerosene is the most commonly used fuel. Gas turbines can burn almost any liquid or gas fuel and have been operated on diesel fuels, avgas, methane and hydrogen. Any energy source that can heat the compressed gas can theoretically be used, including nuclear reactors.

Fuel requirements
ignition

flash point
Is the temperature at wich the fuel will combust in the presence of oxygen

Nitrous
Jet fuels in wikipedia

Refrences

 * Jet Fuel - Kerosene

title: Jet Propulsion/Propellants


text:
Jet Propulsion/Intakes

Air enters a jet engine via the intake or inlet, which is a shaped duct connecting the streamtube (approaching the inlet) to the compressor face. A major objective is to lose as little total (or stagnation) pressure as possible in the process and to act as pre-compressor, whilst minimizing any distortion to the flow entering the compressor. Supersonic intakes often employ cones or ramps to create conical/oblique shock waves to help improve pressure recovery at supersonic flight speeds.

Functional requirements
Intakes are matched to the jet engine to provide maximum performance. This imposes different requirements on the intake depending upon the operating regime.

 * Brake release: maximize mass flow by accelerating the static surrounding air without raising entropy.

 * Takeoff & climb: Maximize pressure recovery while minimizing flow distortions due to off angle conditions

 * Subsonic: maximize pressure recovery at speed and altitude

 * Maneuver: Maximize mass throughput for given speed

 * Supersonic: maximize pressure recovery at speed and altitude without suffering unstarts

 * Hover (VTOL): Maximum mass flow with minimal hot gas reingestion

Pressure recovery
The incoming air flow is diffused. For subsonic flows a divergent duct is commonly used and for supersonic flows a convergent divergent duct is used. Supersonic intakes usually require movable structures to perform well. Without such measures lower performance results.

Distortion avoidance
The intake straightens the flow at high angles of attack and sideslip conditions. Using flow splitters, the low energy boundary layers next to fuselages can also be removed to provide uniform flow at the compressor face.

Noise suppression
Intakes usually have noise suppression surface treatments to reduce forward noise transmission.

EMF suppression
Compressor faces have a distinct dignature that can be suppressed by appropriately shaped screens, intake surface treatments and intake vanes.

Pitot
A diverging forward facing duct is most often used. The length of the duct is governed by the flow straightening, boundary layer development and diffusion requirements.

3D compression (Conical centrebody)
For supersonic applications. Conical shockwaves from the central conical ramp are used to progressively compress the supersonic flow till a terminating normal shockwave makes the flow subsonic. From that shock wave onwards a divergent duct is used to diffuse the subsonic flow.

The cone can be moved depending upon the speed of operation although the cone angle cannot easily be changed.

2D compression (ramp)
A ramp is used to generate the inclined shockwaves to provide compression. The ramp angle is varied depending upon speed of operation. At low speeds the ramp can be oriented to provide minimal acceleration of the flow.

title: Jet Propulsion/Intakes


text:
User:Kushboy

I'm a film studenet at FSU.

title: User:Kushboy


text:
Jet Propulsion/Combustors

Fuel is injected into the compressed air stream, vaporized, and burned. Typical fuel to air ratios are as low as 1:60 (vs 1:14 of stoichiometric) and flame stabilization is difficult.

The compressor exit flow is diffused and divided into the primary and secondary flows. Since conventional flame velocities are low the primary flow is swirled and fuel is injected to provide the recirculation to stabilize the flame.

The burning area is enclosed by a perforated liner which assists in directing the flame and provides a heat shield for the surrounding structure. The chamber liner is cooled by the secondary air which subsequently mixes with the burning primary flow and cools the burnt gases to the required temperature.

The early combustion chambers were "can" shaped, and needed individual ignition sources and tuning.

The intermediate design was can-annular or cannular which connected the individual can chambers and provided better uniformity of combustion.

Annular combustors have a more compact axisymmetric design with only the swirl vanes and injector nozzles locating the primary flame positions. Annular designs are more space and energy efficient.

Emissions
Understanding of combustion processes has allowed the development of smokeless combustors.

Annular combustors with dual injection rings are used in engines such as the GE90. Both annuluses are lighted for take off thrust. Under lighter loads such as cruise only one row operates.

Afterburners
An afterburner (or reheat) is a combustor located immediately upstream of the engine final nozzle, where fuel is burnt to raise the nozzle entry gas temperature, thereby increasing the net thrust of the engine. Because of the relatively high fuel consumption associated with afterburning, the system has to be used sparingly. A variable area nozzle is normally fitted to accommodate the increased gas volume flow when the afterburner is alight. Increasing the nozzle area enables a satisfactory compression match to be maintained, as nozzle temperature is increased. Afterburning is used mainly on military aircraft to reduce take-off roll and to overcome the additional drag encountered when the aircraft is flying at transonic and supersonic conditions. Concorde, the supersonic airliner, also incorporated engine afterburning, but the system was unlit at supersonic cruise, which considerably enhanced the aircraft's range.

title: Jet Propulsion/Combustors


text:
Cookbook talk:Hummus (Greek)

i tought that this was a Turkish food?!

No, It's not Turkish (I own a Turkish restaurant), but it's definately NOT Greek. It is Middle Eastern, and the name Humus (Homous, Hommos etc etc) is Arabic. Most probably it's from the region around Lebanon. --Alper 14:32, 12 August 2006 (UTC)

It is a common missconception that Hummus is a Greek recipe. I see this frequently in UK supermarkets. It's deffinetly middle-eastern.

- Yiannis

I have seen MANY varients from all over. ie from palistine/israel they add some parsley to it and like lebanon they add a little more garlic.

--Majnoon (talk) 15:54, 22 December 2010 (UTC)

title: Cookbook talk:Hummus (Greek)


text:
Find Employment/Industries

The U.S. economy is comprised of industries with diverse characteristics. For each industry covered in the Career Guide, detailed information is provided about specific characteristics: The nature of the industry, working conditions, employment, occupational composition, training and advancement requirements, earnings, and job outlook. This chapter provides an overview of these characteristics and the outlook for the various industries and economy as a whole.

Nature of the Industry
Industries are defined by the processes they use to produce goods and services. Workers in the United States produce and provide a wide variety of products and services and, as a result, the types of industries in the U.S. economy range widely from agriculture, forestry, and fishing to aerospace manufacturing. Each industry has a unique combination of occupations, production techniques, inputs and outputs, and business characteristics. Understanding the nature of the industry is important because it is this unique combination that determines working conditions, educational requirements, and the job outlook for each of the industries discussed in the Career Guide.

Industries consist of many different places of work, called establishments. Establishments are physical locations in which people work, such as the branch office of a bank, a gasoline service station, a school, a department store, or a plant that manufactures machinery. Establishments range from large factories and corporate office complexes employing thousands of workers to small community stores, restaurants, professional offices, and service businesses employing only a few workers. Establishments should not be confused with companies or corporations, which are legal entities. Thus, a company or corporation may have a single establishment or more than one establishment. Establishments that use the same or similar processes to produce goods or services are organized together into industries. Industries are, in turn, organized together into industry groups. These are further organized into industry subsectors and then ultimately into industry sectors. For the purposes of labor market analysis, the Bureau of Labor Statistics organized industry sectors into industry supersectors. A company or corporation could own establishments classified in more than one industry, industry sector, or even industry supersector.

Each industry subsector is made up of a number of industry groups, which are, as mentioned, determined by differences in production processes. An easily recognized example of these distinctions is in the food manufacturing subsector, which is made up of industry groups that produce meat products, preserved fruits and vegetables, bakery items, and dairy products, among others. Each of these industry groups requires workers with varying skills and employs unique production techniques. Another example of these distinctions is found in utilities, which employs workers in establishments that provide electricity, natural gas, and water.

There were slightly more than 8 million private business establishments in the United States in March 2004. Business establishments in the United States are predominantly small; 59.9 percent of all establishments employed fewer than 5 workers in March 2004. However, the medium-sized to large establishments employ a greater proportion of all workers. For example, establishments that employed 50 or more workers accounted for only 4.6 percent of all establishments, yet employed 56.3 percent of all workers. The large establishments those with more than 500 workers accounted for only 0.2 percent of all establishments, but employed 17.3 percent of all workers. Table 1 presents the percent distribution of employment according to establishment size.

The average size of these establishments varies widely across industries. Most establishments in the construction, wholesale trade, retail trade, finance and insurance, real estate and rental and leasing, and professional, scientific, and technical services industries are small, averaging fewer than 20 employees per establishment. However, wide differences within industries can exist. Hospitals, for example, employ an average of 724.9 workers, while physicians offices employ an average of 10.1. Similarly, although there is an average of 14.3 employees per establishment for all of retail trade, department stores employ an average of 124.1 people but jewelry stores employ an average of only 5.8.

Establishment size can play a role in the characteristics of each job. Large establishments generally offer workers greater occupational mobility and advancement potential, whereas small establishments may provide their employees with broader experience by requiring them to assume a wider range of responsibilities. Also, small establishments are distributed throughout the Nation every locality has a few small businesses. Large establishments, in contrast, employ more workers and are less common, but they play a much more prominent role in the economies of the areas in which they are located.

Table 1. Percent distribution of establishments and employment in all private industries by establishment size, March 2004 Establishment size (number of workers) 	Establishments 	Employment

Total 100.0 	100.0

1 to 4 59.9 	6.8

5 to 9 16.9 	8.4

10 to 19 11.1 	11.2

20 to 49 7.6 	17.3

50 to 99 2.6 	13.3

100 to 249 1.4 	16.4

250 to 499 0.4 	9.3

500 to 999 0.1 	6.6

1,000 or more 0.1 	10.7

Working Conditions
Just as the goods and services produced in each industry are different, working conditions vary significantly among industries. In some industries, the work setting is quiet, temperature-controlled, and virtually hazard free, while other industries are characterized by noisy, uncomfortable, and sometimes dangerous work environments. Some industries require long workweeks and shift work, but standard 40-hour workweeks are common in many other industries. In still other industries, a lot of the jobs can be seasonal, requiring long hours during busy periods and abbreviated schedules during slower months. Production processes, establishment size, and the physical location of work usually determine these varying conditions.

One of the most telling indicators of working conditions is an industrys injury and illness rate. Overexertion, being struck by an object, and falls on the same level, are among the most common incidents causing work-related injury or illness. In 2003, approximately 5.0 million nonfatal injuries and illnesses were reported throughout private industry. Among major industry divisions, manufacturing and construction tied for the highest rate of injury and illness 6.8 cases for every 100 full time workers while financial activities had the lowest rate 1.7 cases. About 5,700 work-related fatalities were reported in 2004; the most common events resulting in fatal injuries were transportation incidents, contact with objects and equipment, assaults and violent acts, and falls.

Work schedules are another important reflection of working conditions, and the operational requirements of each industry lead to large differences in hours worked and in part-time versus full-time status. In food services and drinking places, for example, fully 38.0 percent of employees worked part time in 2004 compared with only 1.5 percent in motor vehicles and motor vehicle equipment manufacturing. Table 2 presents industries having relatively high and low percentages of part-time workers.

Table 2. Part-time workers as a percent of total employment, selected industries, 2004 Industry 	Percent part-time

All industries 15.9

Many part-time workers

Food services and drinking places 38.0

Clothing and clothing accessories stores 33.1

Grocery stores 31.4

Arts, entertainment, and recreation 28.7

Child day care services 28.2

Social assistance 25.9

Motion picture and video industries 24.7

Educational services 21.0

Few part-time workers

Chemical manufacturing, except drugs 3.6

Aerospace product and parts manufacturing 3.3

Mining 3.3

Computer and electronic product manufacturing 3.2

Pharmaceutical and medicine manufacturing 2.7

Utilities 2.5

Iron and steel mills and steel product manufacturing 2.5

Motor vehicles and motor vehicle equipment manufacturing 1.5

The low proportion of part-time workers in some manufacturing industries often reflects the continuous nature of the production processes that makes it difficult to adapt the volume of production to short-term fluctuations in product demand. Once begun, it is costly to halt these processes; machinery must be tended and materials must be moved continuously. For example, the chemical manufacturing industry produces many different chemical products through controlled chemical reactions. These processes require chemical operators to monitor and adjust the flow of materials into and out of the line of production. Because production may continue 24 hours a day, 7 days a week under the watchful eyes of chemical operators who work in shifts, full-time workers are more likely to be employed. Retail trade and service industries, on the other hand, have seasonal cycles marked by various events that affect the hours worked, such as school openings or important holidays. During busy times of the year, longer hours are common, whereas slack periods lead to cutbacks in work hours and shorter workweeks. Jobs in these industries are generally appealing to students and others who desire flexible, part-time schedules.

Employment
The total number of jobs in the United States in 2004 was 145.6 million. This included 12.1 million self-employed workers, 141,000 unpaid workers in family businesses, and 133.5 million wage and salary jobs including primary and secondary job holders. The total number of jobs is projected to increase to 164.5 million by 2014, and wage and salary jobs are projected to account for more than 152.1 million of them.

As shown in table 3, wage and salary jobs are the vast majority of all jobs, but they are not evenly divided among the various industries. Education, health, and social services had the largest number of jobs in 2004 with almost 28 million. Manufacturing, construction, and utilities had almost 21.9 million jobs, including 14.3 million manufacturing and 7.0 million construction jobs. The trade supersector was nearly as large, with about 20.7 million jobs, followed by professional and business services with 16.4 million jobs in 2004. Among the industries covered in the Career Guide, wage and salary employment ranged from only 156,200 in steel manufacturing to over 13 million in health care. The three largest industries education services, health care, and food services and drinking places together accounted for 34.7 million jobs, over one-quarter of the Nation's wage and salary employment.

Table 3. Wage and salary employment in industries covered in the Career Guide, 2004 and projected change, 2004-14 (Employment in thousands) Industry 	2004 	2014 	2004-14 Employment 	Percent distribution 	Employment 	Percent distribution 	Percent change 	Employment change

All industries 133,478 	100.0 	152,093 	100.0 	13.9 	18,615

Agriculture and natural resources 1,672 	1.3 	1,567 	1.0 	-6.3 	-105

Agriculture, forestry, and fishing 1,149 	0.9 	1,090 	0.7 	-5.2 	-60

Mining 207 	0.2 	180 	0.1 	-12.9 	-27

Oil and gas extraction 316 	0.2 	297 	0.2 	-6.1 	-19

Manufacturing, construction, and utilities 21,864 	16.4 	21,872 	14.4 	0.0 	8

Aerospace product and parts manufacturing 444 	0.3 	480 	0.3 	8.2 	36

Chemical manufacturing, except drugs 596 	0.5 	510 	0.3 	-14.4 	-86

Computer and electronic product manufacturing 1,326 	1.0 	1,232 	0.8 	-7.1 	-94

Construction 6,964 	5.2 	7,757 	5.1 	11.4 	792

Food manufacturing 1,498 	1.1 	1,555 	1.0 	3.8 	57

Machinery manufacturing 1,142 	0.9 	995 	0.7 	-12.8 	-146

Motor vehicle and parts manufacturing 1,109 	0.8 	1,171 	0.8 	5.6 	62

Pharmaceutical and medicine manufacturing 291 	0.2 	367 	0.2 	26.1 	76

Printing 665 	0.5 	600 	0.4 	-9.8 	-65

Steel manufacturing 156 	0.1 	135 	0.1 	-13.4 	-21

Textile, textile product, and apparel manufacturing 701 	0.5 	380 	0.2 	-45.8 	-321

Utilities 570 	0.4 	563 	0.4 	-1.3 	-8

Trade 20,689 	15.5 	22,814 	15.0 	10.3 	2,125

Automobile dealers 1,254 	0.9 	1,407 	0.9 	12.2 	153

Clothing, accessory, and general merchandise stores 4,205 	3.1 	4,628 	3.0 	10.1 	423

Grocery stores 2,447 	1.8 	2,607 	1.7 	6.6 	160

Wholesale trade 5,655 	4.2 	6,131 	4.0 	8.4 	476

Transportation 4,250 	3.2 	4,756 	3.1 	11.9 	506

Air transportation 515 	0.4 	560 	0.4 	8.8 	45

Truck transportation and warehousing 1,907 	1.4 	2,174 	1.4 	14.0 	267

Information 3,138 	2.4 	3,502 	2.3 	11.6 	364

Broadcasting 327 	0.2 	362 	0.2 	10.7 	35

Motion picture and video industries 368 	0.3 	430 	0.3 	17.1 	63

Publishing, except software 671 	0.5 	715 	0.5 	6.5 	44

Software publishers 239 	0.2 	400 	0.3 	67.6 	161

Telecommunications 1,043 	0.8 	975 	0.6 	-6.5 	-68

Internet services providers, web search portals, and data processing services 388 	0.3 	496 	0.3 	27.8 	108

Financial activities 8,052 	6.0 	8,901 	5.9 	10.5 	849

Banking 1,783 	1.3 	1,751 	1.2 	-1.8 	-31

Insurance 2,260 	1.7 	2,476 	1.6 	9.5 	215

Securities, commodities, and other investments 767 	0.6 	888 	0.6 	15.8 	121

Professional and business services 16,414 	12.3 	20,980 	13.8 	27.8 	4,566

Advertising and public relations services 425 	0.3 	520 	0.3 	22.4 	95

Computer systems design and related services 1,147 	0.9 	1,600 	1.1 	39.5 	453

Employment services 3,470 	2.6 	5,050 	3.3 	45.5 	1,580

Management, scientific, and technical consulting services 779 	0.6 	1,250 	0.8 	60.5 	471

Scientific research and development services 548 	0.4 	613 	0.4 	11.9 	65

Education, health, and social services 27,973 	20.957 	34,399 	22.6 	23.0 	6,426

Child day care services 767 	0.6 	1,062 	0.7 	38.4 	295

Educational services 12,778 	9.6 	14,901 	9.8 	16.6 	2,123

Health care 13,062 	9.8 	16,626 	10.9 	27.3 	3,564

Social assistance, except child day care 1,365 	1.0 	1,810 	1.2 	32.6 	445

Leisure and hospitality 12,479 	9.3 	14,694 	9.7 	17.7 	2,215

Arts, entertainment, and recreation 1,833 	1.4 	2,293 	1.5 	25.1 	460

Food services and drinking places 8,850 	6.6 	10,301 	6.8 	16.4 	1,451

Hotels and other accommodations 1,796 	1.3 	2,100 	1.4 	16.9 	304

Government and advocacy, grantmaking, and civic organizations 11,047 	8.3 	12,170 	8.0 	10.2 	1,123

Advocacy, grantmaking, and civic organizations 1,231 	0.9 	1,410 	0.9 	14.5 	179

Federal Government 1,943 	1.5 	1,993 	1.3 	2.5 	50

State and local government, except education and health 7,872 	5.9 	8,767 	5.8 	11.4 	895

 * Note: May not add to totals due to omission of industries not covered in the Career Guide.

Although workers of all ages are employed in each industry, certain industries tend to possess workers of distinct age groups. For the previously mentioned reasons, retail trade employs a relatively high proportion of younger workers to fill part-time and temporary positions. The manufacturing sector, on the other hand, has a relatively high median age because many jobs in the sector require a number of years to learn and perfect specialized skills that do not easily transfer to other firms. Also, manufacturing employment has been declining, providing fewer opportunities for younger workers to get jobs. As a result, one-forth of the workers in retail trade were 24 years of age or younger in 2004, compared with only 8.2 percent of workers in manufacturing. Table 4 contrasts the age distribution of workers in all industries with the distributions in five very different industries.

Table 4. Percent distribution of wage and salary workers by age group, selected industries, 2004 Industry 	Age group 16 to 24 	25 to 44 	45 to 64 	65 and older

All industries 14 	47 	36 	4

Computer systems design and related services 7 	63 	29 	1

Educational services 9 	42 	45 	3

Food services and drinking places 44 	39 	15 	2

Telecommunications 8 	56 	34 	2

Utilities 5 	43 	50 	2

Employment in some industries is concentrated in one region of the country. Such industries often are located near a source of raw or unfinished materials upon which the industry relies. For example, oil and gas extraction jobs are concentrated in Texas, Louisiana, and Oklahoma; many textile mills and products manufacturing jobs are found in North Carolina, South Carolina, and Georgia; and a significant proportion of motor vehicle manufacturing jobs are located in Michigan and Ohio. On the other hand, some industries such as grocery stores and educational services have jobs distributed throughout the Nation, reflecting the general population density.

Occupations in the Industry
The occupations found in each industry depend on the types of services provided or goods produced. For example, because construction companies require skilled trades workers to build and renovate buildings, these companies employ large numbers of carpenters, electricians, plumbers, painters, and sheet metal workers. Other occupations common to construction include construction equipment operators and mechanics, installers, and repairers. Retail trade, on the other hand, displays and sells manufactured goods to consumers. As a result, retail trade employs numerous retail salespersons and other workers, including more than three-fourths of all cashiers. Table 5 shows the industry sectors and the occupational groups that predominate in each.

Table 5. Industry sectors and their largest occupational group, 2004 Industry sector 	Largest occupational group 	Percent of industry wage and salary jobs

Agriculture, forestry, fishing, and hunting Farming, fishing, and forestry occupations 	61.1

Mining Construction and extraction occupations 	33.3

Construction Construction and extraction occupations 	66.2

Manufacturing Production occupations 	52.1

Wholesale trade Sales and related occupations 	24.7

Retail trade Sales and related occupations 	52.5

Transportation and warehousing Transportation and material moving occupations 	56.0

Utilities Installation, maintenance, and repair occupations 	25.6

Information Professional and related occupations 	29.1

Finance and insurance Office and administrative support occupations 	51.4

Real estate and rental and leasing Sales and related occupations 	22.7

Professional, scientific, and technical services Professional and related occupations 	42.6

Management of companies and enterprises Office and administrative support occupations 	33.6

Administrative and support and waste management and remediation services Office and administrative support occupations 	23.2

Educational services, private Professional and related occupations 	59.6

Health care and social assistance Professional and related occupations 	42.6

Arts, entertainment, and recreation Service occupations 	57.2

Accommodation and food services Service occupations 	84.0

Government Professional and related occupations 	43.7

The Nations occupational distribution clearly is influenced by its industrial structure, yet there are many occupations, such as general managers or secretaries, that are found in all industries. In fact, some of the largest occupations in the U.S. economy are dispersed across many industries. For example, professional and related occupations is among the largest in the Nation while also experiencing the fastest growth rate. . (See table 6.) Other large occupational groups include service occupations, office and administrative support occupations, sales and related occupations, and management, business, and financial occupations.

Table 6. Total employment and projected change by broad occupational group, 2004–14 (Employment in thousands) Occupational group 	Employment, 2004 	Percent change, 2004-14

Total, all occupations 145,612 	13.0

Professional and related occupations 28,544 	21.2

Service occupations 27,673 	19.0

Office and administrative support occupations 23,907 	5.8

Sales and related occupations 15,330 	9.6

Management, business, and financial occupations 14,987 	14.4

Production occupations 10,562 	-0.1

Transportation and material moving occupations 10,098 	11.1

Construction and extraction occupations 7,738 	12.0

Installation, maintenance, and repair occupations 5,747 	11.4

Farming, fishing, and forestry occupations 1,026 	-1.3

Training and Advancement
Workers prepare for employment in many ways, but the most fundamental form of job training in the United States is a high school education. Better than 88 percent of the Nations workforce possessed a high school diploma or its equivalent in 2004. However, many occupations require more training, so growing numbers of workers pursue additional training or education after high school. In 2004, 28.7 percent of the Nations workforce reported having completed some college or an associate's degree as their highest level of education, while an additional 29.5 percent continued in their studies and attained a bachelor's or higher degree. In addition to these types of formal education, other sources of qualifying training include formal company-provided training, apprenticeships, informal on-the-job training, correspondence courses, Armed Forces vocational training, and non-work-related training.

The unique combination of training required to succeed in each industry is determined largely by the industrys production process and the mix of occupations it requires. For example, manufacturing employs many machine operators who generally need little formal education after high school, but sometimes complete considerable on-the-job training. In contrast, educational services employs many types of teachers, most of whom require a bachelors or higher degree. Training requirements by industry sector are shown in table 7.

Table 7. Percent distribution of workers by highest grade completed or degree received, by industry sector, 2004 Industry sector 	High school diploma or less 	Some college or associate degree 	Bachelor's or higher degree

All industries 41.6 	28.7 	29.5

Agriculture, forestry, fishing, and hunting 64.3 	21.4 	14.2

Mining 60.4 	21.8 	17.8

Construction 64.7 	24.5 	10.8

Manufacturing 51.5 	25.1 	23.4

Wholesale trade 42.7 	29.0 	28.3

Retail trade 50.6 	32.3 	17.1

Transportation and warehousing 52.6 	31.7 	15.6

Utilities 38.7 	34.1 	27.0

Information 26.7 	31.3 	42.0

Finance and insurance 24.9 	31.6 	43.4

Real estate and rental and leasing 36.2 	31.7 	32.2

Professional, scientific, and technical services 14.4 	25.1 	60.6

Administrative and support and waste management services 55.3 	28.4 	16.3

Educational services 17.8 	19.0 	63.2

Health care and social assistance 30.6 	34.8 	34.7

Arts, entertainment, and recreation 39.5 	31.8 	28.6

Accommodation and food services 60.7 	28.4 	11.0

Persons with no more than a high school diploma accounted for about 64.7 percent of all workers in construction; 64.3 in agriculture, forestry, fishing, and hunting; 60.7 percent in accommodation and food services; 60.4 percent in mining; 51.5 percent in manufacturing; and 50.6 in retail trade. On the other hand, those who had acquired a bachelors or higher degree accounted for 63.2 percent of all workers in private educational services; 60.6 percent in professional, scientific, and technical services; 43.4 percent in finance and insurance; and 42.0 percent in information.

Education and training also are important factors in the variety of advancement paths found in different industries. Each industry has some unique advancement paths, but workers who complete additional on-the-job training or education generally help their chances of being promoted. In much of the manufacturing sector, for example, production workers who receive training in management and computer skills increase their likelihood of being promoted to supervisory positions. Other factors that impact advancement and that may figure prominently in the industries covered in the Career Guide include the size of the establishments, institutionalized career tracks, and the mix of occupations. As a result, persons who seek jobs in particular industries should be aware of how these advancement paths and other factors may later shape their careers.

Earnings
Like other characteristics, earnings differ by industry, the result of a highly complicated process that reflects a number of factors. For example, earnings may vary due to the nature of occupations in the industry, average hours worked, geographical location, workers average age, educational requirements, industry profits, and the degree of union representation of the workforce. In general, wages are highest in metropolitan areas to compensate for the higher cost of living. Also, as would be expected, industries that employ a large proportion of unskilled minimum-wage or part time workers tend to have lower earnings.

The difference in earnings of between the software publishers and the food services and drinking places industries illustrates how various characteristics of industries can result in great differences in earnings. In software publishers, earnings of all wage and salary workers averaged $1,342 a week in 2004, while in food service and drinking places, earnings of all wage and salary workers the averaged only $194 weekly. The difference is large primarily because software publishing establishments employ more highly skilled, full-time workers, while food services and drinking places employ many lower skilled workers on a part time basis. In addition, most workers in software publishing are paid an annual salary, while many workers in food service and drinking places are paid an hourly wage, but many are able to supplement their low hourly wage rate with money they receive as tips. Table 8 highlights the industries with the highest and lowest average weekly earnings.

Table 8. Average weekly earnings of production or nonsupervisory workers on private nonfarm payrolls, selected industries, 2004 Industry 	Earnings

All industries $529

Industries with high earnings

Software publishers 1,342

Computer systems design and related services 1,136

Aerospace product and parts manufacturing 1,019

Scientific research and development services 1,006

Motor vehicle and parts manufacturing 925

Mining 909

Industries with low earnings

Food manufacturing 510

Grocery stores 332

Arts, entertainment, and recreation 313

Hotels and other accommodations 302

Child day care services 299

Food services and drinking places 194

Employee benefits, once a minor addition to wages and salaries, continue to grow in diversity and cost. In addition to traditional benefits paid vacations, life and health insurance, and pensions many employers now offer various benefits to accommodate the needs of a changing labor force. Such benefits sometimes include childcare, employee assistance programs that provide counseling for personal problems, and wellness programs that encourage exercise, stress management, and self-improvement. Benefits vary among occupational groups, full- and part-time workers, public and private sector workers, regions, unionized and nonunionized workers, and small and large establishments. Data indicate that full-time workers and those in medium-sized and large establishments those with 100 or more workers usually receive better benefits than do part-time workers and those in smaller establishments.

Union representation of the workforce varies widely by industry, and it also may play a role in determining earnings and benefits. In 2004, about 13.8 percent of workers throughout the Nation were union members or covered by union contracts. As table 9 demonstrates, union affiliation of workers varies widely by industry. Fully 50.0 percent of the workers in air transportation were union members, the highest rate of all the industries, followed by 37.6 percent in educational services, and 33.0 percent in iron and steel mills and steel product manufacturing. Industries with the lowest unionization rate include computer systems design and related services, 1.3 percent; food services and drinking places, 1.7 percent; and advertising and related services, 1.7 percent.

Table 9. Union members and other workers covered by union contracts as a percent of total employment, selected industries, 2004 Industry 	Percent union members or covered by union contract

All industries 13.8

Industries with high unionization rates

Air transportation 50.0

Educational services 37.6

Iron and steel mills and steel product manufacturing 33.0

Motor vehicles and motor vehicle equipment manufacturing 30.2

Industries with low unionization rates

Banking and related activities 1.9

Advertising and related services 1.7

Food services and drinking places 1.7

Computer systems design and related services 1.3

Outlook
Total employment in the United States is projected to increase by about 14 percent over the 2004-14 period. Employment growth, however, is only one source of job openings. The total number of openings in any industry also depends on the industrys current employment level and its need to replace workers who leave their jobs. Throughout the economy, replacement needs will create more job openings than will employment growth. Employment size is a major determinant of job openings larger industries generally have larger numbers of workers who must be replaced and provide more openings. The occupational composition of an industry is another factor. Industries with high concentrations of professional, technical, and other jobs that require more formal education occupations in which workers tend to leave their jobs less frequently generally have fewer openings resulting from replacement needs. On the other hand, more replacement openings generally occur in industries with high concentrations of service, laborer, and other jobs that require little formal education and have lower wages because workers in these jobs are more likely to leave their occupations.

Employment growth is determined largely by changes in the demand for the goods and services provided by an industry, worker productivity, and foreign competition. Each industry is affected by a different set of variables that determines the number and composition of jobs that will be available. Even within an industry, employment may grow at different rates in different occupations. For example, changes in technology, production methods, and business practices in an industry might eliminate some jobs, while creating others. Some industries may be growing rapidly overall, yet opportunities for workers in occupations could be stagnant or even declining because they are adversely affected by technological change. Similarly, employment of some occupations may be declining in the economy as a whole, yet may be increasing in a rapidly growing industry.

As shown above in table 3, employment growth rates over the next decade will vary widely among industries. Agriculture and natural resources is the only sector in which all of the industries are expected to experience employment declines. Consolidation of farm land, increasing worker productivity, and depletion of wild fish stocks should continue to decrease employment in agriculture, forestry, and fishing. Employment in mining is expected to decline due to laborsaving technology while jobs in oil and gas extraction are expected to decrease with the continued reliance on foreign sources of energy.

Employment in manufacturing, construction, and utilities is expected to remain nearly unchanged as growth in construction is partially offset by declines in utilities and selected manufacturing industries. Growth in construction employment will stem from new factory construction as existing facilities are modernized; from new school construction, reflecting growth in the school-age population; and from infrastructure improvements, such as road and bridge construction. Employment declines are expected in chemical manufacturing, except drugs; machinery manufacturing; computer and electronic product manufacturing; printing; steel manufacturing; and textile, textile product, and apparel manufacturing. Textile, textile product, and apparel manufacturing is projected to lose about 321,200 jobs over the 2004-14 period more than any other manufacturing industry due primarily to increasing imports replacing domestic products.

Employment gains are expected in some manufacturing industries. Small employment gains in food manufacturing is expected, as a growing and ever more diverse population increases the demand for manufactured food products. Employment growth in pharmaceutical and medicine manufacturing is expected, as sales of pharmaceuticals increase with growth in the population, particularly among the elderly, and with the introduction of new medicines to the market. Both food and pharmaceutical and medicine manufacturing also have growing export markets. Aerospace product and parts manufacturing and motor vehicle and parts manufacturing are both expected to have modest employment increases.

Growth in overall employment will result primarily from growth in service-providing industries over the 2004-14 period, almost all of which are expected to have increasing employment. Job growth is expected to be led by health care and educational services the two largest industries discussed in the Career Guide with large numbers of new jobs also in employment services, food services and drinking places, state and local government, and wholesale trade. When combined, these sectors will account for almost half of all new wage and salary jobs across the Nation. Employment growth is expected in many other service-providing industries discussed in the Career Guide, but they will result in far fewer numbers of new jobs.

Health care will account for the most new wage and salary jobs, about 3.6 million over the 2004-14 period. Population growth, advances in medical technologies that increase the number of treatable diseases, and a growing share of the population in older age groups will drive employment growth. Offices of physicians, the largest health care industry group, is expected to account for about 760,000 of these new jobs as patients seek more health care outside of the traditional inpatient hospital setting.

Educational services is expected to grow by nearly 17 percent over the 2004-14 period, adding about 2.1 million new jobs. A growing emphasis on improving education and making it available to more children and young adults will be the primary factors contributing to employment growth. Employment growth at all levels of education is expected, particularly at the postsecondary level, as children of the baby boomers continue to reach college age, and as more adults pursue continuing education to enhance or update their skills.

Employment in one of the Nations fastest growing industries employment services is expected to increase by more than 45 percent, adding another 1.6 million jobs over the 2004-14 period. Employment will increase, particularly in temporary help services and professional employer organizations, as businesses seek new ways to make their workforces more specialized and responsive to changes in demand.

The food services and drinking places industry is expected to add almost 1.5 million new jobs over the 2004-14 projection period. Increases in population, dual-income families, and dining sophistication will contribute to job growth. In addition, the increasing diversity of the population will contribute to job growth in food services and drinking places that offer a wider variety of ethnic foods and drinks.

Over 890,000 new jobs are expected to arise in State and local government, adding over 11 percent over the 2004-14 period. Job growth will result primarily from growth in the population and its demand for public services. Additional job growth will result as State and local governments continue to receive greater responsibility for administering federally funded programs from the Federal Government.

Wholesale trade is expected to add almost 480,000 new jobs over the coming decade, reflecting growth both in trade and in the overall economy. Most new jobs will be for sales representatives at the wholesale and manufacturing levels. However, industry consolidation and the growth of electronic commerce using the Internet are expected to limit job growth to 8.4 percent over the 2004-14 period, less than the 14 percent projected for all industries.

Continual changes in the economy have far-reaching and complex effects on employment in each of the industries covered in the Career Guide. Jobseekers should be aware of these changes, keeping alert for developments that can affect job opportunities in industries and the variety of occupations that are found in each industry. For more detailed information on specific occupations, consult the 2006-07 edition of the Occupational Outlook Handbook, which provides information on hundreds of occupations.

title: Find Employment/Industries