text:
ERP Internals/Modules/General Ledger

General Ledger produces the enterprise’s financial statements including the Balance Sheet, which shows the enterprise’s assets, liabilities and equity at a point in time, the Income Statement, which shows the enterprise’s income, expenses and net profit over a period of time, the Cash Flow Statement which shows sources and applications of cash, and associated financial reports such as the Trial Balance. The rest of the reports are there to track the numbers on the financial statements back to individual transactions. Most businesses prepare monthly statements. Every ERP package has a General Ledger module.

General Ledger is unusual in that it receives transactions from many other modules. There are two ways to accomplish this: Detail and Summarized. In the detail method, every invoice, check, or other such transaction creates a separate General Ledger transaction. The advantage of this is that the General Ledger is continuously updated in real time so the entire set of ERP tables is in sync. The disadvantage is that there are large numbers of transactions. In the summarized method, transactions are accumulated for some period (typically a day) and posted in summary. Instead of many small transactions, there is a few big ones. The advantage is that there are far fewer transactions. The disadvantage is that the General Ledger is out of sync with the rest of the ERP until the data is posted. This ERP described in this document uses the detailed method.

 * Functions
 * Reports

Tables
The first table is the Chart of Accounts table which contains one record for every General Ledger account. The second table is the Account Balance table which contains the closing balance for every account for one or more accounting periods. The third table is the Budget table which contains one or more budget amounts for each account for each accounting period. The fourth table is the Transaction table which contains one record for every transaction (debit, credit). There is at least one transaction for every account and there can be many.

Data Exchange
General Ledger receives transactions from Accounts Payable, Accounts Receivable, Bank Reconciliation, Fixed Assets, Inventory, Job Costing, Order Entry/Invoicing, Payroll, Purchasing (sometimes).

Transactions
General Ledger has only one transaction. It consists of one or more debits and one or more credits where the total of the debits equals the total of the credits.

General Ledger

title: ERP Internals/Modules/General Ledger


text:
ERP Internals/Modules/Human Resources

Human Resources handles all aspects of managing employees except for paying them, which is done by Payroll. It oversees recruitment and hiring, records attendance, handles training, manages benefits, handles compliance with government regulations and ensures terminations are handled properly. Like Payroll, Human Resources is often very country-specific. Only high-end ERP packages have a Human Resources module.

 * Functions
 * Reports

HR Modules

 * Core HR
 * Learning Management
 * Payroll
 * Benefits
 * HR Intelligence
 * Self-service*- Employees can see their pay, accrued benefits and basic information via the web and update some portions of it (name, and address for example).

Tables
Payroll and Human Resources share the Employee table which contains one record for every employee.

Data Exchange
Human Resources does not send to or receive transactions from other modules.

Transactions
Human Resources

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: ERP Internals/Modules/Human Resources


text:
ERP Internals/Modules/Inventory

Businesses maintain stocks of items for sale to customers or for inclusion ("raw materials") in the manufacturing of new items ("finished goods"). Inventory ties up a lot of money in most businesses. The Inventory module's job is to minimize the amount of money tied up in Inventory without running out and being unable to fill customer orders. Every ERP package has an Inventory module.

Inventory analysis analyzes inventory items by category, supplier, product ID, date, etc. and combinations thereof. The Analysis function selects, sorts, and summarizes these transactions and presents them in numeric and graphic forms. It supports both pre-defined and ad hoc queries.

 * Functions
 * Reports

Tables
The first table is the Item table which contains one record for every inventory item. Each Inventory item includes costing, purchasing, and location information (items can be stocked at more than one warehouse and more than one location within a warehouse). The second table is the Transaction table which contains one record for every transaction (receipt, issue, count, adjustment). There is at least one transaction for every item and there can be many.

Inventory Analysis has a separate, read-only table that is optimized for quick access. Each record in the sales analysis table represents an item receipt. The table is updated once a day.

Data Exchange
Inventory receives data from Purchasing and Accounts Payable and sends transaction to General Ledger.

Transactions
Inventory

title: ERP Internals/Modules/Inventory


text:
ERP Internals/Modules/Job Costing

Sometimes, the item sold requires days or weeks to create. During the process, job costing tracks actual costs, compares them to planned costs, and displays the resulting variances in the form of reports and graphs. Costs are divided into the following categories: Direct Materials, Direct Labor, Sub-contract, and Overhead (or Burden). This allows management to keep track of costs relative to the percentage the job is complete. Every ERP package has a Job Costing module.

 * Functions
 * Reports

Tables
The first table is the Job table which contains one record for every job. The second table is the Transaction table which contains one record for every transaction (labor, materials, sub-contract, adjustment). There is at least one transaction for every job and there can be many

Data Exchange
Job Costing sends transactions to General Ledger and Payroll.

Transactions
Job Costing

title: ERP Internals/Modules/Job Costing


text:
ERP Internals/Modules/Manufacturing

Some businesses build their products from parts and raw materials. These products can range from the assembly of a few standard parts to products with thousands of parts requiring weeks of engineering. Manufacturing (which is actually a group of sub-modules) controls the process by which this is done. Not every ERP package has a Manufacturing module although all the large ones do.

Manufacturing is divided into discrete and process manufacturing. Discrete manufacturers make solid items such as flashlights or cars using Bills of Material. Process manufacturers make liquids or chemicals using formulas or recipes. Manufacturing can also be divided into Make-To-Stock or Make/Engineer-To-Order.

Manufacturing has a Maintain Module Information function that handles the parameters and data tables for the sub-modules.

Here is an incomplete list of the sub-modules in Manufacturing:
 * Bill of Materials
 * Master Production Schedule
 * Advanced Planning and Scheduling
 * Shop Floor Control
 * Quality

Manufacturing

title: ERP Internals/Modules/Manufacturing


text:
ERP Internals/Modules/Order Entry

Customers place orders for products and/or services with the enterprise. Orders can be placed in person, via telephone, mail, fax, e-mail or electronically (see below). If there is a delay between the placing of the order and its fulfillment (for example, if the ordered items have to be picked from Inventory and shipped), Order Entry/Invoicing creates a sales order. Otherwise, the record of this is an invoice. Invoices can be given to the customer at the time of purchase, or mailed, faxed, e-mailed or sent electronically after the goods have been picked, packaged and shipped. Order Entry/Invoicing is usually high-volume and mission-critical in for-profit enterprises. Every ERP package has an Order Entry/Invoicing module. Often, this module has custom processing.

 * Functions
 * Reports

EDI/XML
Orders can be received electronically through EDI or XML. (I will get back to explaining this)

Web Store
Many companies allow customers to order directly from their website. This creates an invoice automatically.

Point of Sale (POS)
Most retail companies use POS in which a scanner reads a Universal Product Code (UPC) attached to the item to create a line on the order invoice.

Configuration
Some enterprises have products or services that are highly configurable or routinely customized to meet customer needs. Using user-defined rules, Configurator conducts a dialog with the user and generates literature, drawings, and bills of material. Order Entry/Invoicing and Quotation/Estimate use Configurator. Inventory items can be flagged as configurable. The details of the options selected are recorded in the invoice often for use by manufacturing.

Tables
Order Entry/Invoicing shares the Customer and Invoice groups of tables with Accounts Receivable. It alone controls the Sales Order tables.

Data Exchange
Order Entry/Invoicing sends transactions to Inventory, General Ledger and Accounts Receivable. It can use Quotation/Estimation data to create invoices.

Transactions
Order Entry

title: ERP Internals/Modules/Order Entry


text:
ERP Internals/Modules/Payroll

Payroll records earnings, calculates deduction and prepares and prints checks and associated payroll reports. It handles hourly and salaried employees using daily, weekly, bi-weekly, semi-monthly, monthly, quarterly, semi-annual, and annual pay periods. It accumulates vacation time and sick leave. It deducts various government taxes and periodically remits them to the government. Payroll is heavily regulated by the government and tends to vary significantly from one country to another. Every ERP package has a Payroll module.

 * Functions
 * Reports

Tables
Payroll and Human Resources share the Employee table which contains one record for every employee. In addition, Payroll has the Transaction table which contains one record for every transaction. There is at least one transaction for every employee and there can be many.

Data Exchange
Payroll receives data from Job Costing and sends transactions to General Ledger.

Transactions
Payroll

title: ERP Internals/Modules/Payroll


text:
ERP Internals/Modules/Purchasing

A Purchase Order authorizes a supplier to ship products to or perform services for the enterprise and invoice them for it. In some enterprises, the purchasing cycle starts with a purchase requisition, which is a request to Purchasing to locate a supplier and issue a purchase order. It is similar to a purchase order except that it does not stipulate a supplier although it can recommend one. It is Purchasing’s job to find a suitable supplier. For large enterprises, this is the start of the Procure To Pay process. Purchasing is the first step in the supply chain, Accounts Payable is the last.

Since a purchase order is a promise to pay, issuing one creates an encumbrance, which becomes a liability when the supplier’s invoice is received.

In manufacturing enterprises, Purchase Orders can be created automatically as part of Advanced Planning and Scheduling. For new goods or services or in the case of a competitive requote, RFQs or RFPs are sent to potential suppliers. When the goods are received, they are processed through Receiving which matches them against the original Purchase Order and records missing or partially shipped items. When the invoice is received, it is matched against the Purchase Order to find any discrepancies in prices. Purchasing interacts with Inventory (increases on-order quantities), Accounts Payable (verify pricing), Receiving (verify quality and quantity), and Shop Floor Control (create planned Purchase Orders).

The two main Purchasing objectives are to: 1) obtain the best price from suppliers for goods or services of acceptable quality and 2) expedite the delivery of goods so that shipments to customers are not delayed.

Purchase analysis analyzes purchases of goods and services by category, supplier, product ID, buyer, department, date, etc. and combinations thereof. The Analysis function selects, sorts, and summarizes these transactions and presents them in numeric and graphic forms. It supports both pre-defined and ad hoc queries using a separate, read-only database that is optimized for quick access. Each record in the database represents a line on a purchase order.

There have to be both Purchase Analysis and Inventory Analysis since some enterprises do not maintain inventory and most enterprises buy additional goods or services that do not enter inventory. Every ERP package has a Purchasing module.

 * Functions
 * Reports

EDI/XML
Purchase Orders can be delivered electronically through EDI or XML. (I will get back to explaining this)

Tables
Purchasing shares the Supplier group of tables with Accounts Payable. The second group consists of the Purchase Order table which contains one record for every purchase order and the Purchase Order Detail table which contains one record for every line on the purchase order. There is at least one detail record for every purchase order and there can be many.

Data Exchange
Purchasing sends data to Inventory and transactions to General Ledger.

Transactions
Different types of transactions in Purchasing are 1) Purchase order creation and approval 2) Communication of Purchase order to Supplier 3) Changes to Purchase Order 4) Shipping of goods by Supplier 5) Receipt of goods 6) Quality check / Returns to Supplier

Purchasing

title: ERP Internals/Modules/Purchasing


text:
ERP Internals/Modules/Quotation

A Quote/Estimate is an offer to provide specified goods and/or services to a potential customer at a specified price. If the document is an “Estimate”, the enterprise is not bound by the prices. If the document is a “Quotation”, the enterprise is bound for a user-defined length of time to the prices. Quote/Estimate is very similar to Order Processing. The entry screens, tables, and output documents are similar. It records the details of the quote/estimate in the database and produces a document that is sent to the potential customer. A Quote/Estimate can have an arbitrary number of documents associated with it. Such a document is usually referred to as a “proposal”. Assuming the potential customer eventually accepts the Quotation or Estimate, the ERP uses the information in it to generate the invoice. Not all ERP packages have a Quotation/Estimation module.

 * Functions
 * Reports

Configuration
Some enterprises have products or services that are highly configurable or routinely customized to meet customer needs. Using user-defined rules, Configurator conducts a dialog with the user and generates literature, drawings, and bills of material. Order Entry/Invoicing and Quotation/Estimate use Configurator. Inventory items can be flagged as configurable. The details of the options selected are recorded in the quotation/Estimate for use by Manufacturing.

Tables
Quotation/Estimation share the Contact and Customer groups of tables with other modules. The second group consists of the Quote/Estimate table which contains one record for every quote/estimate and the Quote/Estimate Detail table which contains one record for every line on the quote/estimate. There is at least one detail record for every quote/estimate and there can be many.

Data Exchange
Quotation/Estimation does not send to or receive transactions from other modules.

Transactions
Quotation

title: ERP Internals/Modules/Quotation


text:
Muggles' Guide to Harry Potter/Magic/Dittany

Overview
Dittany is a plant that was spoken of in the reference One Thousand Magical Herbs and Fungi. In this passage it is said that many believe dittany to have magical powers.

Extended Description
Dittany is first mentioned in Harry Potter and the Philosopher's Stone; Harry, on his Easter holiday, looking it up as part of his studying. No mention of its properties or uses are made at this time.

Not much mention is made of Dittany until Harry Potter and the Half-Blood Prince. There, when Harry uses the Sectumsempra curse on Malfoy, Professor Snape says that he will use Dittany on Malfoy's closed wounds to avoid scarring.

Dittany is used extensively on wounds in Harry Potter and the Deathly Hallows, starting with the occasion when Ron loses a piece of his arm through being Splinched.

Analysis
Dittany is a real herb; the name refers to two different species, White Dittany Dictamnus albus and Dittany of Crete Origanum dictamnus. Both plants have medicinal value against digestive ills, and White Dittany also secretes an oil which has some anti-inflammatory properties.


text:
ERP Internals/Modules/Sales Analysis

Sales are a critical part of every business. Sales Analysis analyzes sales by product type, territory, sales representative, product, customer, date, etc. and combinations thereof. The Analysis function selects, sorts, and summarizes sales transactions and presents them in numeric and graphic forms. It supports both pre-defined and ad hoc queries. Every ERP package has a Sales Analysis module although some bundle it in with other modules.

 * Functions
 * Reports

Tables
Sales Analysis has a separate, read-only table that is optimized for quick access. Each record in the sales analysis table represents a line on an order. The table is updated once a day.

Data Exchange
Sales Analysis receives data from Order Entry/Invoicing.

Transactions
Sales Analysis

title: ERP Internals/Modules/Sales Analysis


text:
ERP Internals/Modules/Service Management

Most businesses do repair and maintenance work on the products they sell. If the work is done under warranty, there is no charge to the customer. Service Management schedules on-site and depot service, defines product warranties, handles service contracts, and controls whether there are charges. Contrast this with Preventative Maintenance. Not every ERP package has a Service Management module although all the large ones do.

 * Functions
 * Reports

Tables
Service Management shares the Customer group of tables with Accounts Receivable. It has a Contract table which contains one record for each service contract with each customer. Associated with this Contract table is a Transaction table which contains one record for every service performed under that contract.

Data Exchange
Service Management creates invoices in Order Entry/Invoicing.

Transactions
Service Management


text:
ERP Internals/Modules/Time Billing

Many professional firms such as lawyers and accountants bill their time to their clients. Time Billing is in charge of collecting this time, sorting it by client, applying the proper rates and generating invoices for Order Entry. Generally time is billed to clients on a weekly or monthly basis. Every ERP package has a Time Billing module.

 * Functions
 * Reports

Tables
Time Billing shares the Customer and Invoice groups of tables (with Accounts Receivable) as well as the Employee table with Payroll. It has a Transaction table in which every hour spent working is allocated to something.

Data Exchange
Time Billing creates invoices in Order Entry/Invoicing.

Transactions
Time Billing

title: ERP Internals/Modules/Time Billing


text:
Practical Electronics/Resistors/Series Proof

This page presents a proof that the resistance of a series network, Rtot of n resistors is the sum of the resistance of each resistor in the network:

First, consider that a voltage across the whole network must be equal to the sum of the voltages across each resistor (Kirchhoff's Voltage Law).

 * $$v_{tot} = \sum\limits_{k = 1}^n {v_k },$$

where vk is the voltage across the kth resistor in the network. Now, from Ohm's Law, we can write:

 * $$i_{tot} R_{tot} = \sum\limits_{k = 1}^n {i_k R_k },$$

where:
 * itot is the current through the entire network
 * Rtot is the resistance of the entire network
 * ik is the current in the kth resistor in the network
 * Rk is the resistance of the kth resistor in the network

Since from Kirchhoff's Current Law we know that the current in each resistor is the same, we can write

 * $$iR_{tot} = i\sum\limits_{k = 1}^n {R_k },$$

where i is the current through the network. Dividing through by i gives us our final answer:

 * $$R_{tot} = \sum\limits_{k = 1}^n {R_k}$$

This is a vital result and should be remembered. Notice that the proof for parallel networks is essentially the same, but uses KCL first and KVL second.

Other interesting points are that this result describes behaviour of parallel capacitive networks and series inductive networks.


text:
ERP Internals/Miscellaneous

This page contains a variety of topics that do not easily fit in the other areas of this document.

Security
Users log in to a company using a username and password. This establishes the data they can see and the functions they can perform. This authorization step is in addition to any log in required by the operating system. To improve security, both the username and the password are encrypted when they are stored in the User table. If the operating system provides file encryption, all data is encrypted. If it doesn't the ERP does the encryption itself.

Alerts
The ERP users define what is routine. When this routine is broken or action is required, the ERP notifies designated users via e-mail (or an instant message if they are on-line) so they can take corrective action. This function occurs in virtually all modules so it is documented here rather than repeatedly.

Design
Number There are fields such as Item Number, Supplier Number, Customer Number, Employee Number, Job Number, etc. that must be unique. Either the users can assign meaningful alphanumeric identifiers or the ERP can assign unique numbers automatically. Only Transaction Numbers are restricted to numbers and always assigned by the ERP.

Reporting Reports can be printed, displayed on the screen, faxed or e-mailed to someone, or exported as a spreadsheet. Some documents such as purchase orders and invoices can also be delivered (and received) electronically.

Attachments Arbitrarily large text notes as well as images, word processing documents, spreadsheets and video files can be attached to every employee, customer, supplier, invoice, order, etc. so that users can store comments and knowledge on-line rather than keeping paper files. For example, a user can scan a supplier’s invoice and attach it to the Accounts Payable invoice record so that everyone can see a copy of the original invoice.

History An ERP allows unlimited history to be kept on-line. For performance reasons, this is kept in a separate set of tables from ordinary transactions but this is transparent to users. Periodically (typically once a day), the oldest transactions are transferred to history. The enterprise decides how much history of each type of data they want to keep on file. Typically, this is at least the current year and the previous year.

Real Time An ERP accepts a transaction and updates all related modules in near real-time. (Typically, this means only a few seconds elapses between entry and final updates).

Drill Down Summary reports allow the user to click on a total to reveal the detail transactions that make up the summarized number.

System Builder An ERP allows the enterprise to specify several dozen criteria and generates a working system customized to their requirements. For example, some enterprises call their customers “clients”, “patients”, “guests”, or “members”, and their suppliers “vendors”. These criteria do not change any logic but make the system more familiar to their users. Another example is that not every enterprise uses every module so menus can be customized to remove modules and functions that are not being used.

Multi-currency
This means the ability to handle more than one currency. Often this is offered as if it is a separate module but it affects any module that includes dollar amounts which is virtually all of them. The ERP package has a defined set of currencies with conversion rates between them.

Internationalization
This refers to the ability to run in more than one country. Obviously, this includes multiple languages but it also includes different calendar systems and different ways of displaying dates and numeric amounts.

Currency
An ERP can accommodate a defined set of currencies, has conversion rates between them, and can recognize gains and losses on exchange. European nations have special needs because they are required to accept payment in either their national currency or the Euro regardless of what currency the invoice was issued in. Field sizes can change depending on the currency (for example the Japanese Yen and the Italian lire are tiny and field amounts are corresponding bigger but have no decimal places).

Different currencies require different symbols. In North America, the currency symbol is displayed immediately to the left of the most significant digit. In other countries, it is displayed immediately to the right of the least significant digit.

Digit Separator
In many countries, the function of “,” (comma) and “.” (period) are reversed from the North American convention. In other countries, different characters are used. For example, Switzerland uses “!” and India used different spacing (three digits for the first thousand and two digits thereafter). Japan uses a different ideograph between every four digits.

Rounding Rules
In North America, if the last digit is less than five, we drop it and the rest of the digits. If it is above five, we add one to the next digit to the left and drop the rest of the digits. If it is equal to five, 50% of the time, we follow rule one and the rest of the time, we follow rule two. In other countries, the rounding rules are different.

Language
An ERP can serve users in their own language simultaneously (user A can be using English, user B Spanish simultaneously). This can have implications for the size of messages and captions as well as the direction in which they are displayed (English reads top to bottom and left to right, other languages read right to left or top to bottom in columns). Ideographic languages such as Japanese had tens of thousands of ideographs rather than a couple of dozen letters.

Calendar
There are several calendars in use in the world in addition to the Gregorian calendar used in North America and Europe. Islamic countries can use the calendar with 28-day months as prescribed in the Qur’an. In Japan, dates can be displayed at the year of the current emperor’s reign. In Israel, the official calendar is the Hebrew one. In addition, the sequence in which days, months, and years are displayed varies from one locale to another. In Europe, dates are commonly displayed in the format year/month/day. In North America, they are normally displayed month/day/year. Although dates are stored in a standard format, they must be converted to and from the local calendar for data entry and display. If the enterprise deals with people’s birth dates or projected date of death, dates can occasionally be over 100 years in the past or the future. Some commercial leases can be up to 99 years long. If the enterprise deals with artwork or antiquities, dates can be an arbitrary number of years in the past.

Web-enabled
Any function that a user can do at a desktop can be done via a browser. The same log in is required.

Multi-company
This means the ability to have several different companies with one set of the software, Although the companies may be owned by the same people, they have different sets of tables with different passwords and access codes.

User Defined Fields (UDF)
Most records contain additional fields that the enterprise can use to hold information specific to them. These fields consists of dates, text and numbers. In addition to the fields in the records, there is a parameter that holds the name of the UDF. For purposes of simplicity and clarity, UDFs are omitted from the table definitions. Typically, the UDFs include a date, an amount, and a text field.

Comments
Master, header and line records allow the addition of comments. These have the format:
 * Date
 * Text

For the purposes of simplicity and clarity, these tables are not defined separately.

Attachments
Master, header and line records allow documents and drawings to be attached. The purpose of this is to allow all information relating to the invoice, etc. on-line. For purposes of simplicity and clarity, these fields are not defined separately.

Segmented Keys
Keys such as Customer Number, Supplier Number, Item Number, Account Number, and Employee Number are often divided into two or more segments each of which can be of specified length and composition (numeric, alphabetic, etc.). For example Account Number often has the format xxxx-xx in which the first set of four digits is the major account (such as Rent) and the second set of two digits is the department or branch.

Batches
Some enterprises gather many transactions together and enter them as a batch. Commonly a unique number is assigned to the batch and a control total of some amount (such as invoice amount) is calculated independently to verify that all the transactions were entered correctly. Batches are most common in Accounts Payable, Accounts Receivable, and General Ledger.

Databases
Smaller ERPs often restrict themselves to a single database such as Microsoft's SQL Server. Larger ERPs tend to run on all of the popular databases include SQL Server, Oracle, and IBM's DB/2.

Platforms
Smaller ERPs often restrict themselves to a single operating system such as Microsoft's Windows. Larger ERPs tend to run on all of the common operating systems.

Data Import/Cleanup
For small amounts of data (hundreds of records), it is simpler to key in the data to the new system. For larger amounts of data, the data must be imported from the previous system. This cannot be entirely automated but the skeleton of the programs that import the data are commonly supplied as part of the ERP package. Commonly companies clean up their data (customers, suppliers, inventory items) before they move it to the new systems

title: ERP Internals/Miscellaneous


text:
Practical Electronics/Resistors/Parallel Proof

This page presents a proof that the resistance of a parallel network, Rtot of n resistors is the reciprocal of the sum of the reciprocals of the individual resistors:

First, consider that a current into (and out of) the whole network, itot, must be equal to the sum of the currents in each resistor (Kirchhoff's Current Law).

 * $$i_{tot} = \sum\limits_{k = 1}^n {i_k },$$

where ik is the current in the kth resistor in the network. Now, from Ohm's Law, we can write:

 * $${{v_{tot} } \over {R_{tot} }} = \sum\limits_{k = 1}^n ,$$

where:
 * vtot is the voltage across the entire network
 * Rtot is the resistance of the entire network
 * vk is the voltage across the kth resistor in the network
 * Rk is the resistance of the kth resistor in the network

Since we know that the voltage across each resistor is the same (a trivial case of Kirchhoff's Voltage Law), we can say

 * $${{v} \over {R_{tot} }} = \sum\limits_{k = 1}^n ,$$

where v is the voltage across the network. Dividing through by v gives us our final answer:

 * $${{1} \over {R_{tot} }} = \sum\limits_{k = 1}^n .$$

This is also sometimes equivalently written as:

 * $$R_{tot} = {1 \over {\sum\limits_{k = 1}^n  }}$$

This is a vital result and should be remembered. Notice that the proof for series networks is essentially the same, but uses KCL first and KVL second.

Other interesting points are that this result describes behaviour of series capacitive networks and parallel inductive networks.


text:
ERP Internals/Modules/Bond Manager

Bond Manager keeps track of the enterprise’s bondholders and pays interest on bonds. Only large ERP packages have a Bond Manager module. Normally only a publicly traded company would use this module.

 * Functions
 * Reports

Tables
The first group of tables consists of the Bondholder table which contains one record for every bondholder and the Bondholder Contact table which contains one record for every contact at each bondholder. There is at least one contact record for every bondholder and there can be several. The second table is the Transaction table which contains one record for every transaction (issue, sale, interest, adjustment). There is at least one transaction for every bondholder and there can be many.

Data Exchange
Bond Manager sends transactions to Bank Reconciliation and General Ledger.

Transactions
The first type of transaction is the issuing of one or more bonds to a bondholder.

The second type of transaction is the paying of interest to a bondholder.

The third type of transaction is recording the sale of a bond by a bondholder.

The fourth type of transaction is miscellaneous adjustments to the bond.

Bond Manager

title: ERP Internals/Modules/Bond Manager


text:
ERP Internals/Modules/Share Manager

Share Manager keeps track of the business’s shareholders and pays dividends on shares when they are declared. It handles stock splits and allows both preferred and common shares. Only large ERP packages have a Share Manager module. Normally only a publicly traded company would use this module.

 * Functions
 * Reports

Tables
The first group of tables consists of the Shareholder table which contains one record for every shareholder and the Shareholder Contact table which contains one record for every contact at each shareholder. There is at least one contact record for every shareholder and there can be several. The second table is the Transaction table which contains one record for every transaction (issue, sale, dividend, adjustment). There is at least one transaction for every shareholder and there can be many.

Data Exchange
Share Manager sends transactions to Bank Reconciliation and General Ledger.

Transactions
The first type of transaction issues one or more shares to a shareholder.

The second type of transaction pays dividends to a shareholder.

The third type of transaction records the purchase of one or more shares from a shareholder.

The fourth type of transaction increases the number of shares through a stock split.

The fifth type of transaction records miscellaneous adjustments to the stock record.

Share Manager

title: ERP Internals/Modules/Share Manager


text:
Cookbook:Apple Pudding

| American cuisine | Vegetarian Cuisine | Dessert

Ingredients

 * ¾ cup white granulated sugar
 * 1 egg
 * ¼ cup flour
 * 1¼ teaspoons baking powder
 * 1 pinch of salt
 * 1 teaspoon vanilla
 * 1 cup chopped walnuts or hickory nuts
 * ½ cup chopped apples

Procedure

 * 1) Beat sugar and egg until smooth.
 * 2) Beat in flour, baking powder, salt, and vanilla.
 * 3) Stir walnuts or hickory nuts and apples into the mixture.
 * 4) Pour into a greased Dutch oven or 9 x 9-inch pan.
 * 5) Bake at 325°F (160°C) for 30 minutes.

Notes, tips, and variations

 * If you like topping, use whipped cream or ice cream.

title: Cookbook:Apple Pudding


text:
Cookbook:Champagne Vinaigrette

| French cuisine | Vegetarian Cuisine

Ingredients

 * 1 garlic clove
 * 1 cup champagne vinegar
 * ½ teaspoon freshly ground black pepper
 * 1 pinch salt
 * 2 teaspoons Dijon mustard
 * 2 cups extra virgin olive oil

Procedure

 * 1) Crush garlic clove with the side of the blade of a chef's knife or other flat object. Transfer the clove, leaving it in one piece, to a mixing bowl.
 * 2) Add the vinegar, pepper and salt, and allow to sit for 30 minutes.
 * 3) Remove and discard the garlic. Whisk in the mustard. Slowly add the oil, whisking constantly to emulsify.

Notes, tips, and variations

 * If not using immediately, store in a covered container in the refrigerator. Whisk again or shake container vigorously to re-emulsify before serving.

title: Cookbook:Champagne Vinaigrette


text:
Cookbook:Galician Garbanzo Soup

| American cuisine | Spanish cuisine | Vegetarian Cuisine | beans | Soups

Fast and cheap, this soup will warm you on a cold day!

Ingredients

 * 3 cans (45 oz / 1.26 kg) garbanzo beans, divided
 * 4½ cups vegetable broth or water (or a combination), divided
 * 1 tablespoon olive oil
 * 2 heaping cups chopped onion
 * 1 tablespoon minced or crushed garlic
 * 1 small waxy potato (yellow Finn or Yucon gold), diced (~1 cup)
 * 1 medium carrot, diced
 * 1 medium stalk celery, diced
 * Salt, to taste
 * 1 bay leaf
 * 2 teaspoons dry mustard
 * 2 teaspoons ground cumin
 * 1–2 threads saffron (optional)
 * ½ cup green peas (fresh or frozen)
 * 3 tablespoons red wine vinegar
 * 2 medium-sized ripe tomatoes, peeled and seeded or 1 cup chopped canned tomatoes
 * Freshly ground black pepper and cayenne pepper, to taste
 * Minced fresh basil, for garnish

Procedure

 * 1) Rinse and thoroughly drain garbanzo beans. Place about ⅔ of them in a blender or food processor with 2 cups of broth and/or water, and purée until mostly smooth. Set aside.
 * 2) Place a soup pot or Dutch oven over medium heat and wait for about a minute. Add olive oil and swirl to coat the pan.
 * 3) Add onion and sauté over medium heat for about 5–8 minutes, or until onion is translucent.
 * 4) Add half the garlic plus the potato, carrot, and celery and about ⅛ teaspoon salt, and sauté over medium-low heat for 5 to 8 minutes.
 * 5) Add garbanzo purée, plus remaining broth and/or water and garbanzo beans, and the bay leaf, mustard, cumin, and saffron.
 * 6) Bring to boil, then lower the heat.
 * 7) Cover and simmer for about 30 minutes, stirring occasionally.
 * 8) Stir in the remaining garlic, plus the peas, vinegar, and tomato.
 * 9) Taste to correct salt.
 * 10) Add black pepper and cayenne.
 * 11) Simmer for only about 5 minutes longer.

Notes, tips, and variations

 * Serve topped with minced fresh basil.
 * Serve with a green salad decked out with a mustard-themed dressing, thick slices of pumpernickel bread, and a light Pinot Noir.
 * Vegetable broth comes in 1 quart boxed in most supermarkets. Choose a gluten-free one if your require, or make your own stock.

title: Cookbook:Galician Garbanzo Soup


text:
User:Balin42632003

Hello. My name is Sean Storm and I live in Moultrie, Georgia USA. I am primarily interested in British and Italian foods.

title: User:Balin42632003


text:
User talk:Mrich

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

The copyright holder is usually the creator, the creator's employer, or the last person who was transferred ownership rights. Copyright information on images is signified using copyright templates. The three basic license types on Wikibooks are open content, public domain, and fair use. Find the appropriate template in Image copyright tags and place it on the image page like this:.

Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 04:58, 20 January 2007 (UTC)

title: User talk:Mrich


text:
User talk:Icez~enwikibooks

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

The copyright holder is usually the creator, the creator's employer, or the last person who was transferred ownership rights. Copyright information on images is signified using copyright templates. The three basic license types on Wikibooks are open content, public domain, and fair use. Find the appropriate template in Image copyright tags and place it on the image page like this:.

Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 05:06, 20 January 2007 (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.

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Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:14, 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) 05:03, 19 April 2015 (UTC)

title: User talk:Icez~enwikibooks


text:
User talk:Tom Webb~enwikibooks

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

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Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 05:07, 20 January 2007 (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 Tom Webb. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Tom Webb~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.

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Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:50, 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) 05:36, 19 April 2015 (UTC)

title: User talk:Tom Webb~enwikibooks


text:
User:Avenue of Covina/Sandbox

This is my personal sandbox that I use to test things that I'm experimenting with.

Avenue of Covina 05:29, 20 January 2007 (UTC)

title: User:Avenue of Covina/Sandbox


text:
Ruby Programming/Introduction to objects

Like Smalltalk, Ruby is a pure object-oriented language — everything is an object. In contrast, languages such as C++ and Java are hybrid languages that divide the world between objects and primitive types. The hybrid approach results in better performance for some applications, but the pure object-oriented approach is more consistent and simpler to use.

What is an object?
Using Smalltalk terminology, an object can do exactly three things.

 * 1) Hold state, including references to other objects.
 * 2) Receive a message, from both itself and other objects.
 * 3) In the course of processing a message, send messages, both to itself and to other objects.

If you don't come from Smalltalk background, it might make more sense to rephrase these rules as follows:

 * 1) An object can contain data, including references to other objects.
 * 2) An object can contain methods, which are functions that have special access to the object's data.
 * 3) An object's methods can call/run other methods/functions.

Variables and objects
Let's fire up  to get a better understanding of objects.

$ irb --simple-prompt >> comedian = "Stephen Colbert" => "Stephen Colbert"

In the first line, we created a String object containing the text " ". We also told Ruby to use the variable  to refer to this object.

Next, we tell Ruby to also use the variable  to refer to the same String object.

>> favorite_comedian = comedian => "Stephen Colbert"

Now, we have two variables that we can use to refer to the same String object —  and. Since they both refer to the same object, if the object changes (as we'll see below), the change will show up when using either variable.

Methods
In Ruby, methods that end with an exclamation mark (also called a "bang") modify the object. For example, the method  changes the letters of a String to uppercase.

>> comedian.upcase! => "STEPHEN COLBERT"

Since both of the variables  and   point to the same String object, we can see the new, uppercase text using either variable.

>> comedian => "STEPHEN COLBERT" >> favorite_comedian => "STEPHEN COLBERT"

Methods that do not end in an exclamation point return data, but do not modify the object. For example,  modifies a String object by making all of the letters lowercase. However,  returns a lowercase copy of the String, but the original string remains the same.

>> comedian.downcase => "stephen colbert" >> comedian => "STEPHEN COLBERT"

Since the original object still contains the text " ", you might wonder where the new String object, with the lowercase text, went to. Well, after  printed out its contents, it can no longer be accessed since we did not assign a variable to keep track of it. It's essentially gone, and Ruby will dispose of it.

Reassigning a variable
But what if your favorite comedian is not Stephen Colbert? Let's point  to a new object.

>> favorite_comedian = "Jon Stewart" => "Jon Stewart"

Now, each variable points to a different object.

Let's say that we change our mind again. Now, our favorite comedian is Ellen DeGeneres.

>> favorite_comedian = "Ellen DeGeneres" => "Ellen DeGeneres"

Now, no variable points to the " " String object any longer. Hence, Ruby will dispose of it.


text:
User:Fadookie

Hello. My main user page is at w:User:Fadookie.

66.47.226.206 is also me.

Hey, I get to write Kid's Books? Wow!

title: User:Fadookie


text:
User talk:Killer2021

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

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Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 07:03, 20 January 2007 (UTC)

title: User talk:Killer2021


text:
User talk:Totophe64

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

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Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 07:04, 20 January 2007 (UTC)

Image copyright problems
Thanks for uploading image(s) to Wikibooks. The Wikimedia Foundation is very careful about what Wikibooks includes because of copyright law, and requires that we maintain a strict copyright policy. Some or all of your uploaded files may soon be deleted unless we can determine the copyright holder and status. The copyright holder is usually the creator, the creator's employer, or the last person who was transferred ownership rights. Please take the time to read Media to learn more about what copyright information is required to satisfy our requirements and remember to include this important information for every file that you upload in the future as well. If you have any questions, feel free to contact me, or ask another Wikibookian at the help desk.

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Thanks! '''– MBA ( Bot talk | Mike talk | owner | block ) 01:22, 21 September 2007 (UTC)

 * This is an automated message. Please ignore it if you've already provided license information for all your uploads.

title: User talk:Totophe64


text:
User talk:Zornitsa

Image copyright
Thanks for uploading images on Wikibooks. However, the images may soon be deleted unless we can determine the copyright holder and copyright status. The Wikimedia Foundation is very careful about the images included in Wikibooks because of copyright law (see Wikibooks' Copyright policy).

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Please signify the copyright information on all images you have uploaded or will upload. Remember that images without this important information or giving false information can be deleted by an administrator. If you have any questions, ask them at the Staff lounge. Thank you.--Az1568(Talk) 07:09, 20 January 2007 (UTC)

 * The same problem with Image:Shopska Salata.jpg --Derbeth talk 09:31, 21 January 2007 (UTC)

title: User talk:Zornitsa


text:
User talk:Moshe buchrai~enwikibooks

Hello and welcome to Wikibooks!

Here are some tips to help you get started:
 * You should sign your name on Talk and vote pages using four tildes, like this: ~~~~.
 * Remember to conduct any editing experiments in the sandbox.
 * If you're a Wikipedian, see Wikibooks for Wikipedians for a primer on how things work here (it's a little different).
 * If you want to base your work here on materials from Wikipedia, please use WB:RFI to bring the material over in compliance with the GFDL.
 * If you're an instructor and plan on using wikibooks for a class project, see Guidelines for class projects
 * Please say hello at the Staff Lounge with any questions or ideas.
 * Eventually, you might want to read the Manual of Style and Policies and Guidelines.
 * Please take a look at Naming policy before starting a new book.
 * Remember to maintain a Neutral point of view.
 * Explore, be bold in editing pages, and have fun!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be an idea if you add this page to your "watchlist" so that you can see when any new information is posted there.

Good luck! -- Herby talk thyme 08:20, 20 January 2007 (UTC)

Ofer The Fawn - The Water Riddle
This is probably not appropriate material for Wikibooks as we do not keep source material only annotated texts - as such this will probably be deleted shortly. Please ask if you require help -- Herby talk thyme 08:20, 20 January 2007 (UTC)

Yes, I'm a new user
So only text - not PDF books? I have seen PDF books in the homepage and was wondering how to add Ofer. Read it - it is excting book.

 * No problem but the place you want for that is Wikisource - they deal with original material.  Wikibooks is for "text books" tho I understand the confusion, let me know if I can help  -- Herby  talk thyme 08:35, 20 January 2007 (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 Moshe buchrai. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Moshe buchrai~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 23:29, 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) 05:16, 19 April 2015 (UTC)

title: User talk:Moshe buchrai~enwikibooks


text:
User talk:A'trix

Hello and welcome to Wikibooks!

Here are some tips to help you get started:
 * You should sign your name on Talk and vote pages using four tildes, like this: ~~~~.
 * Remember to conduct any editing experiments in the sandbox.
 * If you're a Wikipedian, see Wikibooks for Wikipedians for a primer on how things work here (it's a little different).
 * If you want to base your work here on materials from Wikipedia, please use WB:RFI to bring the material over in compliance with the GFDL.
 * If you're an instructor and plan on using wikibooks for a class project, see Guidelines for class projects
 * Please say hello at the Staff Lounge with any questions or ideas.
 * Eventually, you might want to read the Manual of Style and Policies and Guidelines.
 * Please take a look at Naming policy before starting a new book.
 * Remember to maintain a Neutral point of view.
 * Explore, be bold in editing pages, and have fun!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be an idea if you add this page to your "watchlist" so that you can see when any new information is posted there.

Good luck! -- Herby talk thyme 08:22, 20 January 2007 (UTC)

title: User talk:A'trix


text:
Acoustics/formulas/Condition

This formula is a template, for inclusion into pages about Acoustics. Use the following syntax to include it:

$$Q_L = \frac{1}{k_{eff}} \sqrt{\frac{Q_{m0}}{Q_E}} = Q_{Lopt}$$

title: Acoustics/formulas/Condition


text:
Acoustics/formulas/Electro acoustic efficiency

This formula is a template, for inclusion into pages about Acoustics. Use the following syntax to include it:

$$\eta \approx 1 - \frac{1}{1 + k_{eff}^2Q_EQ_L} - \frac{1}{1 + \frac{Q_{m0}}{Q_L}}$$


text:
Animal Behavior/Definition

Animal Behavior
Animal Behavior is the scientific study of the wild and wonderful ways in which animals interact with each other, with other living beings, and with the environment. It explores how animals relate to their physical environment as well as to other organisms, and includes topics such as how animals find and defend resources, avoid predators, choose mates, reproduce, and care for their young-ones.

Previous lesser definitions of Animal Behavior include:

 * "Behavior is motion". "Movement, not necessarily movement of the whole animal... muscular contractions" or "The whole function of the nervous system can be summed up in one word, conduction." - In Sherrington's view, the basic elements of behavior was formed in a reflex-arc, where receptor organs receive sensory stimuli and are conducted to an effector organ. This highly reductionist position has received criticism from many angles, specifically, from arguments that it fails to account for spontaneous behaviors, behaviors that are characterized by a lack of motion, as well as disregarding the complexity of emergent properties in behavior.
 * "What a plant or animal does, in the course of an individual's lifetime, in response to some event or change in its environment." - This definition reduces behavior to phenotypic plasticity and is thus not specific enough.
 * "Behavior is all observable or otherwise measurable muscular and secretory responses (or lack thereof) and related phenomena in response to changes in an animal's internal or external environment.” Behavior may include components which do not lend themselves to simple quantification.
 * "Behavior is characterized by entropic and energetic transductions by an organism, in which the long-term averages convert high entropic and low energetic sensory inputs into low entropic and high energetic outputs." - This definition is too incomprehensible to be of great use.

title: Animal Behavior/Definition


text:
Animal Behavior/Scope

=The Aims and Scope of Animal Behavior=

The study of the behavior of animals is very fortunate that students, who enter this field with a wish to learn more about its scientific approaches, are already intrigued by their own observations. Invariably, beginning students come in equipped with detailed descriptions of behavioral eccentricities of their own pets, wildlife, or smaller siblings. The main challenge is for us to understand the fundamental nature of the scientific approach that must be used to study behavior more formally. Only a rigorous experimental characterization of behavioral phenomena will yield common generalities on how and why animals do what they do - rather than providing a simple catalog of anecdotes. The study of behavior thus critically depends on our ability to phrase our general inquiry as a series of questions that can be answered with standard scientific approaches, that are amenable to experimental probes, and which lead to an explicit and unambiguous interpretation of its results.

Niko Tinbergen's legacy as a exceptionally gifted experimentalist include the phrasing of four different types of questions that can be asked of any animal behavior, now simply referred to as Tinbergen's 4 Aims. This paper summarizes the multidisciplinary approach that had guided the emergence of the field of Ethology since its early roots at the beginning of the 20th century. They group broadly into questions about proximate and ultimate explanations. Proximate explanations are closest to the event that is to be explained, while higher, ultimate explanations instead focus on the deeper reasons for why something happened.

Neural, Endocrine, and Genetic Mechanisms
Causes that explain how a behavior is elicited and coordinated. What are the anatomical or physiological mechanisms that underlie the behavior? The behavior is present because the nervous system makes it happen. It includes a search for the impact of genetic components, physiological mechanisms, environmental conditions needed, and hormones on behavior.

Examples:
 * Neural Machinery for Crayfish Escape Behavior

Ontogeny, Development
How does the behavior develop and change during the lifespan of a single individual? The behavior is present because the individual developed an ability to do it this way.

Examples:
 * Human Language Learning

Survival Value
Explanations are phrased as ultimate causes that explain why a behavior has evolved. Selection ought to favor individuals with behaviors that help it increase its reproductive success. The behavior is present because the individual inherited them from parents who were historically successful with this behavior.. This includes a search for functional significance or adaptiveness of behavior.

Phylogeny, Evolution
What were the macroevolutionary patterns of changes that lead to the behavior today?

Phylogeny is the study of evolutionary relatedness among groups of organisms as It treats a species as a group of lineage-connected individuals over time. It attempts to historically characterize the branching processes in which breeding populations have changed over time. The ethologist's view holds that behavioral characteristics, which receive at least a partial genetic contribution, and can be viewed in a phylogenetic perspective like any other morphological trait. The behavior is present because the individual is an offspring from ancestors that had the behavior.

Examples:
 * Courtship Displays in Ducks

=Example - Territoriality in Red-winged Blackbirds= Male red-winged blackbirds are conspicuous and familiar birds throughout most of North America, where they commonly occupy and defend perches near sources of water. Aggressive while defending a territory, they will attack much larger animals, such as ravens, hawks, or humans who encroach upon their territories. In the northern US, male red-winged blackbirds return from their wintering grounds in early March. In rather stunning song-spread display they flaunt their prominent red epaulets, they lower and spread their tails, puff out their feathers, issuing their distinctive ''Cong-a-lee! call''. According to Tinbergen's 4 Aims our interests as to "Why" they would show such a distinctive type of territorial advertising can be organized in a number of different ways.

Aim 1: Proximate Mechanisms
We may ask questions on the particular mechanics that cause the behavior via its underlying neural, endocrine, and genetic mechanisms - i.e., the behavior's proximate causation. Our interests would focus on whether the male is responding to a particular stimulus such as the approach of a rival, what neural mechanisms aid in the detection of key stimuli, what neural circuits, hormonal triggers, or gene products are necessary for the behavior's expression, or how seasonal changes in day length are able to control them?

The vocal organ of birds, the syrinx, is located at the base of the blackbird's trachea. Sound is produced when air flowing through it causes the syringeal walls to vibrate. Muscles modulate the sound shape by changing the tension of the membranes and the bronchial openings. Centers for song production pathways include the High vocal center (HVC); robust nucleus of archistriatum (RA); and the tracheosyringeal part of the hypoglossal nucleus (nXIIts). Both pathways show sexual dimorphism, with the male producing song most of the time. Androgens are believed to play a key role in the expression of male song behaviors as it exhibits a strong correlation with seasonal testosterone profiles. Song is enhanced with testosterone injections and ceases following adult castration. Injections of testosterone induce growth of the HVC and thereby even produce song in female birds, which otherwise would not sing.

Aim 2: Development, Learning
We could also query in what way the territorial display emerges in development. What role does maturation play? To what degree does the behavior depend on learning processes and tutors? What neural substrates are involved in its acquisition?

The song of red-winged blackbird males, like that of many other song birds, is learned. A comparison of hatchlings, which were either deprived of normal song altogether or simply presented with its recording, demonstrated that individuals readily learned their song from conspecifics in the vicinity. Far from a pure cultural transmission of song dialects, however, innate predispositions played an important role. Some individuals were able to learn complex repertoires with minimal stimulation while others were quite reluctant to develop elaborate, species-specific calls. Some remain faithful to their tutors while others improvised readily and invented new versions. The neural signals that subserve vocal learning center on the anterior forebrain pathway with magnocellular nucleus of the anterior neostriatum (LMAN), Area X, and the Dorsolateral Medial thalamus (DLM).

Aim 3: Functional Significance
Alternatively, we may be interested to know what function this particular territorial display serves. If selection favors individuals with a behavior that is beneficial to the bearer's reproductive success, what are the precise benefits bestowed to that individual and its parents? What defines this behavior as successful in evolutionary terms? What factors are turned up by a search for the functional significance or adaptiveness of this behavior?

When red-winged blackbirds were surgically muted, the loss of song affected their ability to defend the territory. Males were captured and replaced by an auditory display of the individual's recorded song to examine whether the broadcasts alone would be sufficient to defend the territories.

Aim 4: Evolution
Does the red-winged blackbird perform its territorial display because its ancestors did it in a similar way? Is it the only one within its clade that has this display? What were the precise patterns of change throughout the evolutionary lineage that result in the behavior today? How does the red-winged blackbird's display compare to that of other blackbirds?

Most members of the red-winged blackbird's evolutionary lineage communicate with simple call notes, suggesting that its specific call features may have been inherited from an ancestral taxon.

=References=

<<Return to Contents Page | <<Chapter 1

title: Animal Behavior/Scope