Christine Azevedo Coste
email: christine.azevedo@inria.fr

Benoît Sijobert
email: benoit.sijobert@inria.fr

Jérome Froger
email: jerome.froger@chu-nimes.fr

Charles Fattal
email: cfattal@cos-asso.org

Demar

Preliminary developments towards closed-loop FES-assistance of posture and gait

Keywords: Functional Electrical Stimulation (FES), Body Area Network (BAN), Closed loop control, gait assistance, posture, transfer assistance, neuroprosthetics

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INTRODUCTION

Functional Electrical Stimulation (FES) allows to assist or restore muscle contraction. Artificial control of natural actuators can benefit from automatic control and robotics theoretical framework. In the context of lower limb stimulation, many studies have investigated closedloop control of joints using various kinds of approaches [START_REF] Lynch | A comparison of closed-loop control algorithms for regulating electrically stimulated knee movements in individuals with spinal cord injury[END_REF]. Local control of individual joints has to be also considered from the global perspective of the function to restore (walking, standing...) ensuring a safe and optimal posture. Posture control has also been investigated by several teams [START_REF] Ajoudani | A neuro-slidingmode control with adaptive modeling of uncertainty for control of movement in paralyzed limbs using functional electrical stimulation[END_REF]. Consequently the controlled variable can concern individual joint state [START_REF] Qiu | Intelligent algorithm tuning PID method of function electrical stimulation using knee joint angle[END_REF], joint stiffness [START_REF] Jaime | Paraplegic standing supported by FES-controlled ankle stiffness[END_REF] or a more global variable such as body center of mass (Jovic et al., 2012a), [START_REF] Vette | Closed-loop control of functional electrical stimulation-assisted arm-free standing in individuals with spinal cord injury: a feasibility study[END_REF]. In order to improve efficiency, robustness and adaptability closed-loop control has been considered in many published studies. Feedback control implies the availability of information related to the state of the controlled variable. Various sensors have been used for this purpose: goniometers [START_REF] Qiu | Intelligent algorithm tuning PID method of function electrical stimulation using knee joint angle[END_REF], instrumented walker, instrumented orthotic devices [START_REF] Jezernik | Sliding mode closed-loop control of FES: controlling the shank movement[END_REF], Electro Myography (EMG) [START_REF] Zhang | Evoked electromyography-based closed-loop torque control in functional electrical stimulation[END_REF]. If, electrical stimulation (ES) can be external, i.e applied at the skin surface, it can also be implanted [START_REF] Guiraud | Implanted functional electrical stimulation: case report of a paraplegic patient with complete SCI after 9 years[END_REF] and in this latter context Electro Neurography (ENG) measuring afferent nerve fibers activity could be a solution [START_REF] Hansen | Evaluating robustness of gait event detection based on machine learning and natural sensors[END_REF][START_REF] Djilas | Spike sorting of muscle spindle afferent nerve activity recorded with thin-film intrafascicular electrodes[END_REF][START_REF] Djilas | Interpretation of muscle spindle afferent nerve response to passive muscle stretch recorded with thin-film longitudinal intrafascicular electrodes[END_REF]. Sensors have to be adapted to the type of neuroprosthesis (implanted/ surface) and to the function to be assisted or restored. Depending if FES is applied acutely hoping for functional recovery of the patient or chronically, the technological choices also have to be adapted. In a research context and for validation purposes, multiple sensors are commonly embedded on the patients. From a practical point of view, this will not be acceptable for an every-day use. This also means that in real applications, only partial and imprecise information might be available. Similarly, complex models with constraining parameter identification process will be hardly considered. These consideration lead our team to investigate solutions to extract from a minimum number of sensors with a minimum of calibration procedure, a maximum of knowledge about the considered motion [START_REF] Sijobert | Validation of Inertial Sensor Fusion Algorithms in the Context of Hemiparetic Gait Assessment[END_REF][START_REF] Azevedo Coste | Detection of freezing of gait in Parkinson disease: preliminary results[END_REF]. In this paper we will only discuss external FES. In this context we have investigated the body area network (BAN) framework [START_REF] Chelius | A Wearable Sensor Network for Gait Analysis: A 6-Day Experiment of Running Through the Desert[END_REF]. Our team has proposed solutions for architectures of networks of sensors and stimulators both for surface [START_REF] Toussaint | Wireless distributed architecture for therapeutic functional electrical stimulation: a technology to design network-based muscle control[END_REF] and implanted contexts [START_REF] Andreu | A distributed architecture for activating the peripheral nervous system[END_REF]. 1). Indeed, when dealing with FES assistance of posture and gait, an important characteristic is the co-existence of two controllers: the natural vs the artificial one. Artificial control of lower limb(s) needs to cooperate with voluntary motion [START_REF] Azevedo Coste | Rehabilitation of functional posture and walking: Coordination of healthy and impaired limbs[END_REF]. It is non sense to perform a local optimization without integrating a general vision of the function to restore (here posture and gait). From an application point of view, it is also important to keep in mind that observation should rely on a low number of sensors for the proposed solutions to be realistic. In the following, we illustrate this approach through two examples: transfer assistance in spinal cord injured (SCI) patients and gait assistance in post-stroke hemiplegic patients.

TRANSFER ASSISTANCE IN SCI: COORDINATING UPPER AND LOWER BODY

Restoring standing by means of functional electrical stimulation (FES) in spinal cord injured (SCI) individuals has been a subject of research since many years [START_REF] Kralj | Electrical stimulation providing functional use of paraplegic patient muscles[END_REF]. First approaches used open-loop stimulation to ensure knee locking and hyperextension of hips while subjects used their arms to maintain balance. In these conditions, due to early fatigue of artificially stimulated muscles, a paraplegic person is able to stand only for a few minutes mainly due to knee unlocking. Solutions have been proposed to face fatigue problem by optimizing stimulation parameters [START_REF] Bijak | Stimulation parameter optimization for FES supported standing up and walking in SCI patients[END_REF], performing posture switching in order to allow muscles to relax [START_REF] Krajl | Posture switching for prolonging functional electrical stimulation standing in paraplegic patients[END_REF], or implementing closed-loop control laws [START_REF] Braz | Efficacy and stability performance of traditional versus motion sensor-assisted strategies for FES standing[END_REF][START_REF] Matjai | Control of posture with {FES} systems[END_REF].

It is important to have in mind that SCI individuals intensively use their upper limbs during daily activities, such as performing pivot transfers and wheelchair propulsion. This overuse induces shoulder pain and damages. This is critical for these persons whose autonomy is highly linked to arm contribution. FES-assisted sit to stand (STS) should not increase the already existing risk of shoulder complications. In healthy population, STS can be achieved without arm participation and trunk role in this postural task is essential [START_REF] Jovic | Impact of Functional Electrical Stimulation of Knee Joints during Sitting Pivot Transfer Motion for Paraplegic People[END_REF]. Trunk motions should not be considered as negligible disturbances in any postural task, indeed center of mass position is mainly influenced by trunk motion. Depending on the lesion level, the trunk control is totally or partially under subject voluntary control. In a STS task, trunk movements should participate with and not against the transfer. We have proposed to restore a coordination between upper and lower parts of the body in order to optimize STS transfers in terms of reducing arm participation during the rising motion. We have developed an algorithm to observe trunk acceleration during STS transfer and trigger stimulation at the chosen moment (figure 2) and investigated the influence of the timing of muscle stimulation onset on the upper limb efforts. More details can be found here in previous publications (Jovic et al., 2012a[START_REF] Jovic | Decreasing the Arm Participation in Complete Paraplegic FES-Assisted Sit to Stand[END_REF]. Trunk acceleration was acquired via a single-axis wireless accelerometer placed between subjects shoulders. Force sensors were mounted on handles to record arm efforts. Stimulation current amplitude was adjusted muscle by muscle to ensure maximum contraction. We have shown, in the 6 participants, that when lower limb stimulation started before or around the maximum trunk acceleration peak, the applied arm forces during STS motion were significantly lower when compared with the situation when stimulation started after maximum trunk acceleration peak. We also showed that arm forces applied during STS motions were slightly higher when the onset of stimulation occurred after the maximum trunk acceleration signal, vs. when participants stood up using only arm support. In other words FES-assistance was worse than no assistance at all if triggered too late. For each participant, and also depending on training, the optimal moment for triggering FES can be different and has to be specific.

Coordinating lower and upper body in STS task is necessary to reduce arm support and preserve shoulders.

GAIT ASSISTANCE

This section is adapted from (Azevedo Coste et al., 2014a) where more details can be found about the method. The intention here is to illustrate the general concept of limb coordination in FES-assistance.

Walking impairment after stroke can be addressed through drop foot stimulators (DFS) [START_REF] Lyons | A review of portable FES-based neural orthoses for the correction of drop foot[END_REF]. Current DFS, through activation of the common peroneal nerve, elicit ankle dorsiflexion on swing phase of gait. Dropped foot stimulators are generally piloted by a force sensing resistor heel switch placed in the shoe of the affected side with stimulation triggered ON by heel rise of the affected foot and triggered OFF by heel strike. Other sensors have been proposed instead of foot switch such as tilt sensors [START_REF] Shimada | Clinical application of acceleration sensor to detect the swing phase of stroke gait in functional electrical stimulation[END_REF][START_REF] Everaert | Effect of a foot-drop stimulator and ankle-foot orthosis on walking performance after stroke: a multicenter randomized controlled trial[END_REF]. Eventhough closed-loop control in this context has been considered [START_REF] Melo | Technical developments of functional electrical stimulation to correct drop foot: Sensing, actuation and control strategies[END_REF][START_REF] Seel | Feedback control of foot eversion in the adaptive peroneal stimulator[END_REF], real-time control of stimulation intensity is still not available in existing devices. The modulation of FES intensity to provide more optimized delivery of stimulation and also to regulate dorsiflexion in the presence of disturbances, such as fatigue, may increase the number of potential users of the technology [START_REF] Breen | A system for the delivery of programmable, adaptive stimulation intensity envelopes for drop foot correction applications[END_REF]. Modulation of stimulation parameters would enable adaptation to context and environment changes. Some studies have suggested that improvement in orthotic performance could be achieved using stimulus intensity shapes matching more closely the muscle biphasic activation pattern than the trapezoidal shape classically used in the stimulators [START_REF] Byrne | Effect of walking speed changes on tibialis anterior EMG during healthy gait for FES envelope design in drop foot correction[END_REF], this requires more than one event driven stimulation.

Human gait is a cyclic phenomenon which can be modeled as a non-linear oscillator [START_REF] Héliot | Online generation of cyclic leg trajectories synchronized with sensor measurement[END_REF]. Based on this, we have developed a solution to continuously track the evolution of the ongoing gait cycle. The principle is to identify the parameters of a Van Der Pol oscillator from the signal of a sensor placed on a subject limb. Indeed, during walking the signal should elicit a cyclic behavior. We have shown that thigh and shank inclination can be good candidates. In the phase plane the periodic stable solution of the oscillator is a trajectory called limit cycle. The phase is a coordinate along this limit cycle ie a continuous information on the gait cycle execution. An isochron matrix can also be defined in order to extend the phase to the vicinity of the limit cycle. Based on the oscillator properties, it can be demonstrated that a state observer of the system can be built. From the estimated state variables the phase of the oscillator can be computed (figure 3).

We have proposed to extract the tilt angle information from one inertial sensor fixed on patient shank. Extra details can be found in (Azevedo Coste et al., 2014a). A reference pattern is computed from several steps of a given individual and is used to identify the oscillator parameters. The phase can be then estimated online from ongoing measured data.

We have experimentally validated this model on 20 poststroke hemiplegic subjects by analyzing the phase estimation corresponding to heel strike and heel off compared to information available from a walkway GAITRite system. As a first attempt to use this real-time information, we show the feasibility of triggering an electrical stimulator based on the information provided by an inertial sensor placed on unaffected shank. We embedded our gait observation algorithm within a system involving a commonly used drop foot stimulator (Odstock ODFS III) to control deficient foot dorsiflexion. We compared the situation when ES was triggered from a heel switch and when ES was triggered when the phase values were comprised between 0 and 40%. The observation of the unaffected leg shank angle could successfully be used to trigger the stimulator. Theoretically the stimulator can be triggered at any instant of the gait cycle from the continuous phase information.

Using only one sensor placed on the shank of the unaffected leg a complete information on the gait cycle evolution can be extracted, i.e a global knowledge on the task performance. Extending the body area network by including additional sensors could allow us to investigate advanced control laws [START_REF] Héliot | Online CPG-Based Gait Monitoring and Optimal Control of the Ankle Joint for Assisted Walking in Hemiplegic Subjects[END_REF][START_REF] Benoussaad | Nonlinear Model Predictive Control of Joint Ankle by Electrical Stimulation For Drop Foot Correction[END_REF].

CONCLUSION

We have described a general approach to functional assistance using functional electrical stimulation. Most of the concepts could be adapted to other assistive techniques (orthoses, exoskeletons...). The proposition is to consider this problematic from a multi-scale point of view. The controller should be hierarchic and include local and global levels, going from joint to posture considerations. This is very similar to human natural sensori-motor architecture [START_REF] Azevedo | Bipedal locomotion: toward unified concepts in robotics and neuroscience[END_REF]. We insisted on the necessity to coordinate unaffected and paretic limb motions through the cooperation of voluntary and artificial controllers. This theoretical framework is associated to technical developments around body area networks (BAN) integrating sensors and actuators nodes. We have illustrated the interest of the approach in the context of two situations: sit to stand assistance in complete paraplegia and drop foot correction in hemiplegia. Some experimental validation has been achieved in both cases and from these preliminary results new investigation topics are on going.

This article presented ongoing developments towards a robust framework for body area network of sensors and stimulators in order to propose advance solutions of FESclosed loop control. The approach is illustrated through preliminary results in the context of post-stroke hemiplegic gait assistance and complete spinal cord injured patient transfer assistance.

  natural controller of healthy limbs ar3ficial controller (FES) of pare3c limbs

Fig. 1 .

 1 Fig. 1. Integrating global and local observations for a better coordination of valid and deficient limbs in posture and gait functional assistance involving FES. Illustration of drop-foot correction in post-stroke hemiplegic and transfer assistance in SCI contexts. The present article intends to insist on two main aspects of closing the loop in FES-assisted gait and posture: local joint control and global function control. From a feedback point of view this implies to observe both local behaviors and global posture including voluntary movements (figure1). Indeed, when dealing with FES assistance of posture and gait, an important characteristic is the co-existence of two controllers: the natural vs the artificial one. Artificial control of lower limb(s) needs to cooperate with voluntary motion[START_REF] Azevedo Coste | Rehabilitation of functional posture and walking: Coordination of healthy and impaired limbs[END_REF]. It is non sense to perform a local optimization without integrating a general vision of the function to restore (here posture and gait). From an application point of view, it is also important to keep in mind that observation should rely on a low number of sensors for the proposed solutions to be realistic. In the following, we illustrate this approach through two examples: transfer assistance in spinal cord injured (SCI) patients and gait assistance in post-stroke hemiplegic patients.

Fig. 2 .

 2 Fig. 2. Observing upper body to control deficient leg muscles in SCI FES-assisted transfer context.

Fig. 3 .

 3 Fig. 3. Observing unaffected leg movements to control deficient leg muscles in drop foot correction context.

ACKNOWLEDGEMENTS

This article is a synthesis of several contributions from former collaborations. Related articles are cited.


Arslan Tariq
email: arslan@univ-orleans.fr

Rana Mazen Kebewar
email: mazen.kebewar@univ-orleans.fr

Mazen Kebewar

« The Political Economy of FDI Flows into Developing Countries: Does the Depth of International Trade Agreements Matter? »

Keywords: Foreign direct investment, free trade agreements, partial scope agreements, domestic institutions. JEL Classification: F21, F55, F59 investissement direct étranger, accords de libre-échange, accords de portée partielle, Codes JEL: F21, F55, F59. institutions domestiques

 and no feedback effect found in sample. The results state that (1) The conclusion of FTAs-CUs attract FDI inflows into the developing countries significantly whereas PSAs are insignificant (2) FTAs-CUs are complementary to democratic regime whereas the conditional effect of PSA with democracy on levels of FDI inflows is insignificant.

Introduction

Foreign Direct Investment (FDI) inflows have recently been the most persistent source of capital inflows in developing countries. In 2010, these countries have attracted FDI inflows of $574 billion constituting the share of 46.29% of total inward investment (UNCTAD 2011). This extensive growth of FDI has, consequently, given rise to the competition among policy makers in developing countries that adopt higher investment incentives and make ex ante commitments to foreign investors about the continuity of policies. The instruments they use to make commitments are the membership in international organizations such as GATT-WTO. Other instruments are conclusion of Bilateral Investment Treaties (BIT) and Preferential Trade Agreements (PTAs). The conclusion of PTAs is considered a new phenomenon in establishing credibility of commitment in the goal to attract FDI flows (e.g. [START_REF] Büthe | The Politics of Foreign Direct Investment into Developing Countries: Increasing FDI through International Trade Agreements?[END_REF]. Apart from international institutions, the domestic politics also plays a crucial role and the regime type conditions the impact of PTAs in attracting FDI [START_REF] Büthe | The Interaction of Domestic and International Institutions: Democracy, Preferential Trade Agreements, and Foreign Direct Investment into Developing Countries[END_REF]. PTAs are not homogenous. There exist numerous types of PTAs. WTO distinguished among their various types. The focus here is on the differing impact of various types of trade agreements on FDI flows and also to examine whether the democratic regime moderates the effect of different types on FDI inflows.

The governments are confronted with obsolescing bargain in the process of attracting foreign investments. In the obsolescing bargain, the investors (MNCs) are in a position to locate operations in one of the multiple possible locations around the world. To attract investments, governments offer variety of attractive investment incentives to the foreign firms in the form of reduced taxes, investment grants and wage subsidies [START_REF] Li | Reversal of fortunes: Democracy, property rights and foreign direct investment inflows in developing countries[END_REF]. But FDI is often characterized by a high degree of reversibility and sunk costs (Stasavage 2002b, and[START_REF] Jensen | Democratic Governance and Multinational Corporations: Political Regimes and Inflows of Foreign Direct Investment[END_REF]. Thus, the investors are worried about the credibility of the attractive stances taken by the governments and the successful continuation of the policies after the investment is made. Examples of policy changes include changes to performance requirements, direct expropriation, nationalization, and confiscation of foreign assets [START_REF] Henisz | The Institutional Environment for Multinational Investment[END_REF].

The host developing countries can signal their credibility of commitments at domestic as well as international level. Numerous researchers have found positive impact of a democratic regime on FDI (e.g. [START_REF] Busse | Democracy and FDI" HWWA discussion paper[END_REF]. According to [START_REF] Jensen | Democratic Governance and Multinational Corporations: Political Regimes and Inflows of Foreign Direct Investment[END_REF], democratic political institutions constrain the policy flexibility of the executive thus signaling to foreign investors about policy stability after FDI location. But [START_REF] Li | Democracy, autocracy, and expropriation of foreign direct investment[END_REF] opposed and argued that democracy is not a remedy for eliminating risk of expropriation. There exists contradiction in literature about the impact of democratic regime on FDI. While debates on whether domestic political institutions (specifically, the country's level of democracy) of the host developing country toward foreign investors are effective in establishing the credibility of commitments are still underway, researchers have also analyzed the effect of international institutions such as (GATT-WTO) membership and Bilateral Investment treaties (BIT in their role of establishing the credibility of commitment to attract foreign investments. In addition, most recent studies have examined the effect of International Trade Agreements (PTAs) on FDI flows (Büthe andMilner 2008, 2010) as they contain separate investment chapters and dispute settlement mechanism, thus providing confidence to investor regarding the security of their investments. These studies analyzed this issue based on PTAs dummy variable without considering that not all PTAs provide the same level of investment protection and liberalization. A deeper analysis is needed to take into account the qualitative differences among various types of trade agreements.

This paper builds on the study of [START_REF] Büthe | The Interaction of Domestic and International Institutions: Democracy, Preferential Trade Agreements, and Foreign Direct Investment into Developing Countries[END_REF], who examined the effect of interaction of regime type with PTAs, and analyzed the impact of heterogeneous PTAs, and their interaction with domestic institutions, on FDI inflows to examine the conditional effect. Full-fledged agreements such as Free Trade Agreements and Customs Unions (FTA-CU) serve as a better commitment device as they are associated with domestic political as well as international reputational cost, whereas Partial Scope Agreements (PSA) have limited credibility ascertaining no obvious cost in case of reneging. Each type consists of different arrangements and thus differs in its institutional characteristics. Statistical analysis for 122 developing countries from 1970 to 2005 is done. The method adopted relies on fixed effects estimator which is also robust to control endogeneity on a large panel dataset. The strict exogeneity of results is tested by using a method suggested by [START_REF] Baier | Do free trade agreements actually increase members' international trade?[END_REF].

The rest of the paper is structures as follows: Section (2) presents the review of literature, analyzing the effect of heterogeneous PTAs and discussing the contradiction in impact of regime type on FDI flows. The simultaneous effect of varying types of PTAs and level of democracy is also examined in this section. Section (3) includes explanation of data and results, whereas section (4) concludes.

Theoretical Background of interaction of institutions

Heterogeneity of International Institutions and FDI

At the international level, countries, competing for international production capital, have concluded the establishment of the institutions which bind them of their commitments signaling the partner countries, the persistence of the policies and protecting the rights of the foreign companies making (long term) investments in the host country. The benefit of international institutions lies primarily in the creation of disincentives for states to behave opportunistically by reneging on trade agreements [START_REF] Goldstein | Legalization, Trade Liberalization, and Domestic Politics: A Cautionary Note[END_REF]. Among them, the multilateral institution is GATT-WTO, which has provided the forum for investment provisions and its protection. Apart from the multilateral institutions, there exist regional and bilateral arrangements known as PTAs. Although, varying in the coverage of products with the commitment for tariff reduction, range of issues and entailing the measures for the implementation of those commitments, PTAs offer twofold advantages in the context of attracting FDI: PTAs include strategic instruments such as provisions for investment1

In the light of the above discussion about the advantages of PTAs in attracting production capital, they nevertheless differ in scope and coverage as well as in provision mechanisms and legalization. Trade agreements vary widely in depth and form. WTO distinguishes the , reducing barriers to investment and transaction costs. They provide dynamic benefits such as increased bilateral investment, industrial location and help in growth [START_REF] Schiff | Regional Integration as Diplomacy[END_REF] and secondly, at the same time, they serve as the insurance device and provide mechanisms for making credible commitments to foreign investors about the continuation of policies and treatment of their assets, thus avoiding the time-inconsistency trap, reassuring investors and increased investment [START_REF] Fernandez | Returns to Regionalism: An Analysis of Nontraditional Gains from Regional Trade Agreements[END_REF][START_REF] Simmons | The Legalization of International Monetary Affairs[END_REF][START_REF] Büthe | The Politics of Foreign Direct Investment into Developing Countries: Increasing FDI through International Trade Agreements?[END_REF]. In other words, trade agreements institutionalize the investment process (from negotiations on investment provisions till the mechanisms to protect them after dislocation of firms). In addition to the investment and assurance benefits to investors, PTAs, in general offer lower trade barriers, increase the scope of products to be traded and indirectly decreased costs for investors. agreements according to their form such as partial scope agreements, free trade agreements, customs unions, to which common markets can be added. These agreements range from the simple exchange of trade preferences on limited range of products and investment measures to the harmonization of policies beyond tariffs such as dispute settlement procedures, legality, competition policy, infrastructure and environmental standards. GATT-WTO under the article XXIV permits the formation of FTA under the condition if the partner countries liberalize "substantially all trade" among them. Customs unions are a one step further to FTA entailing common external tariff for all the member countries as introduced by [START_REF] Balassa | Towards a Theory of Economic Integration[END_REF], considering regionalism as gradual process. On the other hand, Partial scope agreements (in which there is little coverage and the level of legalism is very low) are permitted for developing countries under the "enabling clause" to exchange partial tariff preference between members.

The heterogeneity between the institutions entailing different depth and breadth are the drivers of diverse investment outcomes. The reason is due to the involvement of varying provisions regarding investment and dispute settlement, punishment mechanisms and their legal enforceability in trade agreements negotiations. States, while negotiating various agreements can include third party for arbitration (such as International Centre for Settlement of Investment Disputes) in case of dispute emergence, specifically related to investments2 Trade agreements are in variety of forms and the type of agreement at hand influences the type of dispute settlement system favored by member governments [START_REF] Smith | The Politics of Dispute Settlement Design: Explaining Legalism in Regional Trade Pacts[END_REF]. Highly legalized dispute settlement mechanism indicates a strong commitment to the protection of property rights of investors and, subsequently, should be an effective way of attracting investment flows [START_REF] Büthe | The Politics of Foreign Direct Investment into Developing Countries: Increasing FDI through International Trade Agreements?[END_REF]. Also, the effectiveness of an integration agreement depends upon the punishment mechanisms and costs it implies for pursuing bad policy (such as reneging) [START_REF] Schiff | Regional Integration as Diplomacy[END_REF]. Institutions may have relatively strong central authorities and significant operating responsibilities or be little more than forums for consultation [START_REF] Koremenos | The Rational Design of International Institutions[END_REF], the later implying a very low level of legalism permitting the concluding state to reject any proposed settlement in favor to accommodate domestic interest groups and caring about policy discretion to craft policies [START_REF] Smith | The Politics of Dispute Settlement Design: Explaining Legalism in Regional Trade Pacts[END_REF]. No doubt, the low level of legalism still provides investment and assurance benefits to some extent, there are two broader advantages inherent in deeper and broader arrangements. Firstly they generate larger economic gains by freeing 'substantially' all trade and thus investments and secondly by involvement of strong dispute settlement mechanisms and options, they provide greater predictable environment for investors who seek to raise their voice in the event of policy change (ex-post agreement) or expropriation of their assets in the host country after the location of their investments.

. Emphasizing on the differing effects of regional integration agreements on investments, [START_REF] Blomström | Regional integration and foreign direct investment[END_REF] argue that perhaps the most serious challenge facing a study of the relation between regional integration and foreign direct investment is the multi-dimensional character of the issue. As argued, the diversity of trade agreements has differing effects, they not only reduce barriers to trade and investment, and they also provide increased benefits relating to the implementation of credibility of commitment.

A full-fledged trade agreement 3 agreement4 . A strong, liberalizing RIA may lead to a virtuous circle of increased credibility and thus increased investment and growth. On the contrary, a more closed agreement could lead in the opposite direction with reduced credibility and lower investment [START_REF] Schiff | Regional Integration as Diplomacy[END_REF]. For example [START_REF] Abbott | NAFTA and the Legalization of World Politics: A Case Study[END_REF] establishes that though EU and NAFTA5 adopted different institutional and juridical models, they preferred 'hard' law. The broader and deeper agreements such as FTA-CU (and not PSA which involve weaker obligations), ascertaining strongly binding legal commitments, offer advantages to both parties signing an agreement with the objective to increase the flow of investments. First, the hard legal commitments are used by the government of investors or MNC as assurance devices as the potential for opportunism and costs are high for the host countries (Abbot and Snidal 2000). Secondly, for the host countries6

The design of agreement proposed prior to an arrangement also signals the extent of credibility. If the design of arrangement is flexible and weakly legalized where asymmetry of information is high, such as in (PSA), the plausibility of reneging on the agreement cannot be ignored. [START_REF] Goldstein | Legalization, Trade Liberalization, and Domestic Politics: A Cautionary Note[END_REF] argued that although flexibility or "imperfection" could lead to stability and success of agreements, but incentives also exist for states to evade commitments. Also, [START_REF] Abbott | Why states act through Formal International Organizations[END_REF] argued that noncompliance typically results not from deliberate cheating but from ambiguity in agreements. There exists potential that as these loosely integrated (flexible) agreements can be reneged and thus, in turn, they do not provide a strong mechanism to provide confidence to investors. Figure 1 provides the evolution of FTA-CU, PSA and Annual FDI inflows.

, they serve as mechanism to prove their credibility of commitments about the treatment of foreign investors' assets when noncompliance is difficult to assess ex-ante. Focusing on the preferences of countries for using hard law in international economic arrangements, [START_REF] Abbott | NAFTA and the Legalization of World Politics: A Case Study[END_REF] suggests that hard law reduces private risk premiums and intergovernmental transaction costs associated with trade and investment. Thus, reduced uncertainty and costs associated with broader and deeper forms of economic integration augments the flow of investments among the signing parties. Figure ( 1) depicts the evolution of Full-fledged trade agreements (FTA-CU) as well as partial scope agreements (PSA) of developing countries and annual flows of FDI into these countries.

These arguments regarding the heterogeneity of trade agreements and flows of foreign direct investments yield the testable hypothesis:

It can be seen from the figure that FTA-CU and FDI inflows are growing together whereas PSA are showing different trend although the figure shows their similarity with FDI inflows before the year of 1995.

H1: The greater number of FTA-CU a country concludes the greater and significant will be FDI inflows in contrast to the number of PSA concluded.

FDI, in the wake trade agreements, have domestic implications for governments. Therefore, it is important to examine how they react to the varying institutional setups of trade agreements in their ability to attract FDI flows.

Heterogeneous International institutions, domestic politics and credibility of commitment in attracting FDI

The impact of democratic regime type is positive in attracting FDI [START_REF] Busse | Democracy and FDI" HWWA discussion paper[END_REF]). In the same vein, [START_REF] Jensen | Democratic Governance and Multinational Corporations: Political Regimes and Inflows of Foreign Direct Investment[END_REF] has argued that democratic political institutions at the domestic level constrain the committed policy flexibility of the executive. Compared to regimes tending towards autocracy, democratic regimes are characterized by heterogeneous veto players which weaken the ability of the executive to back on ex-ante commitments. Democracies signal their intention to other states and are able to commit credibly and clearly as opposed to authoritarian states [START_REF] Fearon | Domestic political audiences and the escalation of international disputes[END_REF][START_REF] Pevehouse | Regional Trade and Institutional Design: Long After Hegemony?[END_REF]. [START_REF] Li | Reversal of fortunes: Democracy, property rights and foreign direct investment inflows in developing countries[END_REF] have argued that property rights are stronger in democratic regimes, thus providing confidence to investors that they are safe from expropriation of their assets in host countries. However, this argument could also be contradicted in literature. For example, [START_REF] Li | Democracy, autocracy, and expropriation of foreign direct investment[END_REF] argued that democratic regime is not a remedy for eliminating the risk of expropriation. According to [START_REF] Yang | Autocracy, Democracy, and FDI Inflows to the Developing Countries[END_REF] there is no systematic relationship between democracy and FDI inflows. Being a democracy does not help to attract higher levels of FDI. Analyzing the arguments of [START_REF] Jensen | Democratic Governance and Multinational Corporations: Political Regimes and Inflows of Foreign Direct Investment[END_REF] and [START_REF] Li | Reversal of fortunes: Democracy, property rights and foreign direct investment inflows in developing countries[END_REF], he argued that these studies do not offer complete theoretical explanations on how political institutions influence expropriation of foreign assets i.e. they did not analyze opportunistic incentives on part of politicians.

The debate is going on and indecisive, whether democratic countries are credible in respecting the rights of foreign investors and attract FDI, there is another mechanism through which countries can assure investors and attract FDI is by concluding bilateral and regional trade agreements. As argued, trade agreements provide mainly two direct advantages in the context of investments: they include, in general, investment provisions and at the same time, provisions to settle dispute (if raised) related to investments. 7

7 The indirect effect of trade agreements on FDI can be seen from the fact that these arrangements lower tariff barriers leading to increased trade flows. FDI could be closely related to trade flows, either as complementary such as intra-firm or inducing substitution to trade. Thus, through these institutionalized arrangements, the democratic governments ensure the credibility of their policy commitment (ex-post) to foreign investors [START_REF] Büthe | The Interaction of Domestic and International Institutions: Democracy, Preferential Trade Agreements, and Foreign Direct Investment into Developing Countries[END_REF]. In this vein, it is important to understand the dynamics of regime type and domestic veto players in the formation of varying types of trade agreements with the goal to attract foreign firms (ex-ante) and the potential for reneging on agreements concluded. A problem arises at domestic level, when democratic governments pursue the policy of entering into trade agreements, especially the type of agreement proposed. Of crucial importance in this regard are the differences in formal institutions for sharing decisionmaking power that create the potential for veto players [START_REF] Mansfield | Democracy, Veto Players and the Depth of Regional Integration[END_REF]. The democratic political regime has to assume the conflicting interests of domestic institutions before concluding trade agreements. These players are the institutional and partisan actors whose assent is necessary to introduce new policies [START_REF] Tsebelis | Veto Players: How Political Institutions Work[END_REF]. In a coalition government, any one member may veto a certain policy proposal by threatening to withdraw from government if there are certain reservations. In general, the domestic actors are divided into two main categories; median voters 8 and interest groups. The results of [START_REF] Mansfield | Democracy, Veto Players and the Depth of Regional Integration[END_REF] indicate that more the domestic veto players, the higher the probability that the governments will form lower/shallower forms of integration agreements. But the preferences of domestic institutions are diverse i.e. there exists strong heterogeneity in domestic groups as well. Stolper Samuelson theorem predicts that free trade is more beneficial to the working class in labor-abundant countries. Here the workers are winners and capitalists are losers; and vice versa in capital-rich countries. In an unequal country, the median-voter will be labor-rich and capital poor thus it will influence government to adopt pro-labor policies. Median voter approach (pro-labor) is assumed by [START_REF] Levy | A political-economic analysis of free-trade agreements[END_REF] in his widely studied political economy model based on Hecksher-Ohlin framework. Other competing theory in contrast to median voter theory, the lobbying model, also based on two-factor Hecksher-Ohlin framework, Rodrick (1986) argues that capitalist lobby is more concentrated (and possessing better information [START_REF] Goldstein | Legalization, Trade Liberalization, and Domestic Politics: A Cautionary Note[END_REF]) than workers and therefore are more effective in pressurizing the government to conclude the policy which would be more pro-capital thus giving protection to the possessors of capital in labor-abundant countries 9The heterogeneity, described above, among domestic groups gives rise to the alternate choices of legalization and procedures in negotiations of arrangements. The import-competing groups feel themselves threatened as they face potential loss of market share in the presence of foreign firms and production capital. They restrain the government to commit the highly legalized form of arrangement thus falling short of full-fledged arrangement. On the other hand, in the context of developing countries, the state has to fulfill the demands of median voters, which encourage governments of committing highly legalized agreements, also in order to get them reelected as the median voters constitute a larger portion of population. Foreign direct investment is favorable for other part of median voters i.e. consumers in the host country as they help in improving the quality of products from the resulting increased competition thus benefitting consumers. FDI also helps in: technology advancement; getting access to wider global market by integrating to the world economy thus benefiting exporters . 10 8 Median voters are sometimes called 'selectorates' mentioned by [START_REF] Mansfield | Democracy, Veto Players and the Depth of Regional Integration[END_REF] as they make up a broader portion of society in a democracy and choose the leader and keep them in office.

; improved human resources permitting labor force to acquire globally valued skills (promoting general interests and benefiting median voter). In the same vein, as argued that according to Stolper Samuelson theorem, free trade (under the auspices of deeper trade agreements FTA-CU) is beneficial for labor abundant (developing) countries. In other words, the democratic government in the developing country will be more interested in concluding deeper forms of arrangements, which would be utile for welfare of their median voters (labor abundant audience) and also guaranteeing the international investors.

The credibility of commitment by a democratic government, described above, follows the sustainability of policies committed in concluded arrangement. More legalized trade regime will provide more and better information about the domestic distributional implications of trade agreements. This information will mobilize the domestic players in democratic regime to act in favor or against the arrangement [START_REF] Goldstein | Legalization, Trade Liberalization, and Domestic Politics: A Cautionary Note[END_REF]. They further argued that better information will empower protectionists when the governments are in process of concluding trade agreements and free traders on the issues of compliance to existing agreements. Reneging on commitments to FDI may be politically beneficial in the short run as increased income flows from policy changes can be distributed to a small group comprising core political supporters [START_REF] Jensen | Democratic Governance and Multinational Corporations: Political Regimes and Inflows of Foreign Direct Investment[END_REF]. Political leaders realize that liberalization (in the context of trade arrangements) will impose domestic costs and therefore they want to retain discretion to respond in future to uncertain demands for relief from injured groups [START_REF] Smith | The Politics of Dispute Settlement Design: Explaining Legalism in Regional Trade Pacts[END_REF]. Thus, the dynamics of domestic politics create some optimal level of imperfection in the application of international rules [START_REF] Downs | Optimal Imperfection? Domestic Uncertainty and Institutions in International Relations[END_REF]. The compliance with concluded agreements is enforced by other groups also such as median voters. As they constitute a large part of population, therefore cannot be ignored in democratic regimes.

Trade agreements increase domestic costs in the event of contract breach [START_REF] Mitchell | International Institutions and Compliance with Agreements[END_REF][START_REF] Mitchell | International Institutions and Compliance with Agreements[END_REF][START_REF] Tomz | Domestic Audience Costs in International Relations: An Experimental Approach[END_REF] thus enhancing the reliability of the host governments that they will work for the continuity of policies. Also, the cost of reneging on commitment increases with legalization where the potential of opportunistic behavior is high [START_REF] Abbott | Hard and Soft Law in International Governance[END_REF]. Therefore, we argue that domestic cost of reneging on the deeper commitments such as FTA-CU will be higher than the PSA. Deeper trade agreements offer the governments to gain credibility (by increasing costs and locking-in) both at domestic and international level. There exist two types of costs to be beared by a democratic government in the event of noncompliance: International reputational costs [START_REF] Mitchell | International Institutions and Compliance with Agreements[END_REF][START_REF] Mitchell | International Institutions and Compliance with Agreements[END_REF][START_REF] Smith | The Politics of Dispute Settlement Design: Explaining Legalism in Regional Trade Pacts[END_REF] and Domestic audience cost [START_REF] Fearon | Domestic political audiences and the escalation of international disputes[END_REF][START_REF] Tomz | Domestic Audience Costs in International Relations: An Experimental Approach[END_REF]. Since the governments, where the regime type is democratic, seek the support of median voter because they find it more useful to comply with deeper and broader arrangements as the median voter is more concerned (with actions of government) here with respect to the partial arrangements. As anecdotal evidence for this argument, Tomz find the support based on the experimental surveys.

The domestic politics play a role in developed countries also whose investors make investments abroad also in ensuring credibility. The barriers to trade and investment restrict the prospects of benefitting from differences in capital costs between countries. [START_REF] Chase | Economic Interests and Regional Trading Arrangements: The Case of NAFTA[END_REF] finds the support for the argument that reducing barriers through regional trading agreement significantly help investors to move their production facilities. Thus, the investors, being part of the domestic pressure groups and in order to benefit from larger market and at the same time to secure their investments, force their governments to conclude the deeper type of agreement ascertaining the high credibility of policy commitment. [START_REF] Koremenos | The Rational Design of International Institutions[END_REF] argued that nonstate actors participate with increasing frequency in institutional design. They further argued that trade agreements are self conscious creation of states (and to a lesser extent, of interest groups and corporations). Arguing on the same logic but regarding the domestic institutions of U.S., [START_REF] Bhagwati | Termites in the Trading System: How Preferential Agreements Undermine Free Trade[END_REF] maintains that ethnic groups and bureaucracies pushed for particular PTAs. The above arguments lead us to the following hypothesis: H2: The more the country tends towards democracy, the significant positive effect of FTA-CU on FDI inflows rises whereas the effect of PSA remains insignificant.

Empirical Analysis

Data

The sample comprises an unbalanced panel of 122 Non-OECD developing countries from the 1970 to 2005. The data for the dependant variable, FDI inflows as a percentage of GDP is taken from the online version of UNCTAD's Handbook of Statistics. The primary source of the data on Partial Scope Agreements and Free Trade Agreements/Custom Unions is WTO 11 . There exist many agreements that have not been notified to WTO. For that matter, the comprehensive database of preferential trade agreements compiled at Mc Gill University is consulted 12 . Data on variable POLITY which signifies countries' tendency towards democracy is taken from Polity IV Project. Number of Bilateral Investment Treaties signed by specific country is taken from UNCTAD 13 . Data on Political Constraints is extracted from the database compiled by Henisz Witold. Data on Population and GDP per capita is accessed through Penn World Table . GDP growth variable is calculated from GDP variable in constant ( 2005) dollars. GDP per capita is also in constant ( 2005) dollars. The descriptive statistics for variables can be seen in Table (1).

Methodology and Results

Following the introduction of variables, we turn to the empirical linkages between the regime type, trade agreements and FDI flows. The fixed-effect panel analysis comprising 122 developing countries and the entire period of 1970-2005 is performed. The rationale for using fixed effects is that they control for omitted unobservable factors which is source of endogeneity bias. There are two distinct instances of omitted unobservable variables. First, the countries may self select into trade agreements. As [START_REF] Downs | Is the good news about compliance good news about cooperation?[END_REF] argue that governments tend to conclude only those agreements that oblige them to do what they are already doing or want to do. Second, there exist country specific characteristics which are constant over time. If these country characteristics have an impact on the FDI inflows and one or more explanatory variables (notably 11 http://www.wto.org/english/tratop_e/region_e/region_e.htm 12 http://ptas.mcgill.ca/ 13 http://www.unctad.org/Templates/Page.asp?intItemID=2344&lang=1 the trade agreements) then the structural disturbance (which captures heterogeneity across units of observation) will be correlated with those explanatory variables. Unlike other estimation techniques, for example OLS on cross-section data that produce biased estimates or randomeffects models that assume no correlation between unobservables (a i,t

In order to estimate the treatment effect of heterogeneous trade agreements on FDI flows into developing countries and the conditional effect of regime type on these heterogeneous agreements, the following equation is estimated:

𝐹𝐷𝐼 𝑖,𝑡 = 𝛽 0 + 𝛽 1 𝐹𝑇𝐴_𝐶𝑈 𝑖,𝑡-1 + 𝛽 2 𝑃𝑆𝐴 𝑖,𝑡-1 +𝛽 3 𝑃𝑂𝐿𝐼𝑇𝑌 𝑖,𝑡-1 + 𝛽 4 𝐵𝐼𝑇 𝑖,𝑡-1 + 𝛽 5 𝐺𝐴𝑇𝑇_𝑊𝑇𝑂 𝑖,𝑡-1 + 𝛽 6 𝐹𝑇𝐴_𝐶𝑈 * POLITY 𝑖,𝑡-1 + 𝛽 7 𝑃𝑆𝐴 * 𝑃𝑂𝐿𝐼𝑇𝑌 𝑖,𝑡-1 + 𝛽 8 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝑖,𝑡-1 + 𝑎 𝑖,𝑡 + 𝜀 𝑖,𝑡-1

) and the variables of cumulative FTA-CU and cumulative PSA variables, the fixed effects estimator is an unbiased and consistent estimator of the treatment effect of trade agreements.

The dependant variable is in fact the FDI as percentage of GDP. As can be seen all the variables are lagged. The variables showed the trend; therefore they are de-trended also to avoid spurious correlation among the dependant and independent variables.

The results are presented in Table (2). We start the analysis from the impact of regime type in attracting FDI inflows in model ( 1) which is insignificant. Among the control variables of population, GDP Growth and GDP per capita, the variable GDP Growth is positive and significant at 10 percent level. In estimation (2), the effect of international institutions is added in model (1). In the presence of control variables and regime type, the effect of Bilateral Investment Treaties and GATT-WTO membership is significantly positive at 10 percent level. More the country concludes BIT, the more the FDI inflows it experiences. GATT-WTO membership also increases the prospects for a country to attract investments. In model (3), two different types of trade agreements are included such as Free Trade Agreements-Custom Unions (FTA-CU) and Partial Scope Agreements (PSA). The impact of FTA-CU is positive and statistically significant at 10 percent level whereas PSA are also showing positive sign but insignificant. This confirms our first hypothesis (H1) that by concluding more FTA-CU the country gains the confidence of foreign investors, signals its credibility of commitments and thus attract higher FDI inflows. The PSA do not play any role in attracting FDI. The variable of regime type (i.e. POLITY) remains insignificant showing that democracy itself does not signal to foreign investors about the security of their investments. The control variables are showing the same behavior. Population of a country and GDP per capita are insignificant though positive. The last model (4) shows the interaction effect of both types of trade agreements in addition to all other explanatory variables. The sign of the interaction variable between cumulative FTA-CU and POLITY is positive and significant at 5 percent level whereas the interaction effect of cumulative PSA and POLITY is not significantly different from zero. The result confirms our second hypothesis (H2). This shows that more the regime type tends towards democracy, the effect of full-fledged agreements such as FTA-CU is larger and significant to attract FDI. The democratic regime moderates significantly the effect of full-fledged trade agreements on FDI inflows whereas it does not condition the impact of partial scope agreements. The interaction effects can be shown through a graph. Figure 2 shows the effect of FTA-CU on FDI inflows moderated by the democratic level (Polity).

FDI inflows are boosted when a highly democratic country concludes more FTA-CU. Although the effect of low democracy level with larger amount of FTA-CU concluded is at the increasing trend but this is very small. Countries with the higher level of democracy and lower FTA-CU experience lower FDI inflows depicting the importance of FTA-CU in boosting FDI.

The marginal effect of FTA-CU and PSA are calculated for each of the variables conditional on one another along with 99 percent confidence intervals based on variance-covariance matrix [START_REF] Brambor | Understanding Interaction Models: Improving Empirical Analyses[END_REF]. Figure (2) displays the marginal effect for FTA-CU, conditioned by regime type (polity) estimated in model (4). It clearly shows that FTA-CU do not have significant effect on FDI in the countries where polity score is low (i.e. countries having autocratic regime type), whereas, as the level of democracy rises, the FTA-CU show significant and positive effect on FDI. In figure (3), we analyzed the effect of domestic regime type conditioned by FTA-CU. Here, the effect of regime type on FDI is insignificant at any number of FTA-CU signed. In other words, the FTA-CU to which the country is party, does not condition the effect of regime type on FDI and the effect cannot be distinguished from zero at any point. The strict exogeneity of the results is also tested by using a method suggested by [START_REF] Baier | Do free trade agreements actually increase members' international trade?[END_REF]. For this, future level of cumulative FTA-CU is introduced in the regression model. If the changes of this independent variable are strictly exogenous to FDI flow changes, cumulative FTA-CU t+1 should be uncorrelated with the FDI flow and so the coefficient must be insignificant. The result of this variable confirms this and therefore there is no feedback effect.

Concluding Remarks

Foreign Direct Investment (FDI) inflows have recently been the most persistent source of capital inflows in developing countries. This extensive growth of FDI has, consequently, given rise to the competition among policy makers in developing countries and they pursue to conclude international trade agreements to boost foreign direct investment inflows. But, the trade agreements are heterogeneous in nature and there is difference on their impact in attracting FDI. Full-fledged agreements signal credibility of commitments. Also there is debate whether the level of democracy encourages foreign investors to invest. The goal of this paper was to explore in detail the role of heterogeneous international trade agreements in their role to attract FDI flows and to examine the conditional effect of level of democracy in the country on different types of agreements in order to attract FDI flows. Accordingly, the results can be summarized as follows: In the fixed-effects panel analysis, covering a period of 36 years, the impact of full-fledged agreements is found to be significant and positive. They signal the credibility of the host government. At the same time, the impact of partial scope agreements is proved to be insignificant. The level of democracy itself is insignificant but its conditional effect on full-fledged agreements is significant. The moderating effect of democracy on partial scope agreements is found to be insignificant. This shows that democratic regimes do care more about their commitments when they conclude the agreements ascertaining strong dispute settlement mechanisms. These agreements increase the reputational cost for democratic regimes in case of reneging from their commitments. The impact of other international institutions (Bilateral Investment Treaties and GATT-WTO membership) is found to be positive and significant in the earlier estimations but after the introduction of trade agreements, these institutions lost their significance which could be a signal that countries rely more on trade agreements to boost investment rather than other types of institutions. The strict exogeneity of the results is also tested by using a method suggested by [START_REF] Baier | Do free trade agreements actually increase members' international trade?[END_REF] and no feedback effect is found. This research could be continued by introducing individual clauses of trade agreements regarding investment and the level of legalization as democracies are more prone to respect higher commitments. From that one could investigate the heterogeneity in trade agreements and analyze their effect on FDI.

Figure ( 1 )

 1 Figure (1) FTA-CU, PSA and FDI Inflows

  Figure (4) shows the marginal effect of PSA on FDI moderated by regime type in country whereas figure (5) depicts the effect of polity on FDI moderated by PSA. Both figures prove that the effects are insignificant. Partial scope agreements do not have significant effects on FDI moderated by polity.

Figure ( 2 )

 2 Figure (2) MARGINAL EFFECT OF FTA-CU AS A FUNCTION OF POLITY Figure (3) MARGINAL EFFECT OF POLITY AS A FUNCTION OF FTA-CU

Table ( 1

 ( ) DESCRIPTIVE STATISTICS

	Variables	Mean	Std. Deviation	Min	Max
	FDI	2.095	4.798	-65.411	92.104
	Cumulative FTA-CU	0.609	1.478	0	17
	Cumulative PSA	0.631	0.967	0	7
	Democracy (Polity)	-1.056	6.828	-10	10
	GATT-WTO Membership	0.547	0.498	0	1
	Cumulative BIT	7.279	13.456	0	107
	Log (Population)	15.921	1.411	12.292	20.990
	GDP Growth	3.960	8.563	-66.972	168.008
	GDP per capita	8.101	0.984	5.032	11.491

Notes: (FDI): Foreign Direct Investment, (FTA-CU): Free Trade Agreements and Customs Unions, (PSA): Partial Scope Agreements, (Polity): democratic level, (GATT-WTO): membership in international organizations (General Agreement on Tariffs and Trade -World Trade Organization), (BIT): Bilateral Investment Treaties. All variables are de-meaned by country and de-trended. (See section 4 for details). These statistics are based on one-year lagged values.

Table ( 2

 ( ) CONDITIONAL EFFECT OF REGIME TYPE AND HETEROGENEOUS TRADE AGREEMENTS

		(1)	(2)	(3)	(4)
	Cumulative FTA-CU			0.158* (0.088) 0.285** (0.134)
	Cumulative PSA			0.140 (0.188)	0.299 (0.185)
	POLITY	0.013 (0.020)	0.004 (0.019)	0.009 (0.019)	0.011 (0.019)
	Cumulative BIT		0.022* (0.013)	0.016 (0.013)	0.008 (0.014)
	GATT-WTO Membership		1.181* (0.675)	1.080 (0.703)	1.009 (0.666)
	Cumulative FTA-CU (i+1)				-0.069 (0.107)
	Population	-0.010 (1.244)	0.629 (1.118)	1.083 (1.265)	0.522 (1.328)
	GDP Growth	0.055* (0.032) 0.055* (0.032) 0.054* (0.032)	0.056 (0.034)
	GDP per capita	0.577 (0.651)	0.222 (0.682)	0.235 (0.700)	0.275 (0.748)
	Cumulative FTA-CU * POLITY				0.053** (0.024)
	Cumulative PSA * POLITY				-0.009 (0.020)
	Constant	-0.000 (0.027) -0.000 (0.028) -0.000 (0.029)	-0.038 (0.043)
	No. of Countries	122	122	122	119
	Observations	3565	3565	3565	3330
	R-squared	0.015	0.022	0.024	0.027

Notes: (FTA-CU): Free Trade Agreements and Customs Unions, (PSA): Partial Scope Agreements, (Polity): democratic level, (GATT-WTO): membership in international organizations (General Agreement on Tariffs and Trade -World Trade Organization), (BIT): Bilateral Investment Treaties. Regression with robust standard errors for correction of heteroscedacity in parantheses. ** denotes significance at 5 percent; * significant at 10 percent. All variables are de-meaned, de-trended and one-year lagged.

Although trade agreements are negotiated for trade related issues and are intended to increase trade flows, growing number of trade agreements contain investment issues.

Currently, there are 157 signatory States to ICSID convention ( serves as the better commitment device than partial scope http://icsid.worldbank.org).

Although, there is debate that even recent Free Trade Agreements do not offer hundred percent free trade as states do often exclude sensitive sectors such as agriculture, still here we treat them as full-fledged agreements here as they are still better than partial scope arrangements in liberalizing trade and investment and legal enforcement of resolving disputes.

[START_REF] Kahler | Legalization as Strategy: The Asia-Pacific Case[END_REF] argues hard legalization is less significant in looser economic integration and in which the states do not pursue deep integration such as APEC (Asia-Pacific Economic Cooperation), therefore not providing assurance of sincere commitments. APEC is characterized by low levels of precision, delegation, and obligation and not a successful model of regional economic integration[START_REF] Abbott | NAFTA and the Legalization of World Politics: A Case Study[END_REF].

According to WTO, NAFTA is recognized as FTA and EC/EU as CU.

Developing countries in general, as their domestic institutions and political conditions are not stable as compared to developed economies.

Labor-rich countries are developing countries, which are the focus of our analysis here, who obtain benefits from FDI, which comes through institutionalized arrangements providing more credibility.

Investments are encouraged in trade agreements and for that matter the design of arrangement is important. The argument is relating trade and investment; the inclusion of wide range of products is entailed in the formation of deeper agreements.