98 research outputs found
The impact of local taxes on plants location decision
Determinants of plant locations are known to be multiple. Locations of partners and competitors are crucial, as well as the territory's local characteristics. Some local characteristics can be natural. Others, like local taxes, reflect local agents' decisions. To what extent are local taxes taken into consideration during the plant location process? We build a Poisson model to explain the number of firm creations observed in a given municipality in a given year. Correlations and first results tend to show that there exists some unobserved attractivity factors correlated with the level of local taxes. To deal with endogeneity, we present an approach close to the Regression Discontinuity Design. Finally, we find that, everything else being equal, higher local taxes actually deter firms from investing in a given zone.local attractivity, local taxes, plant location decisions, regression discontinuity design, Poisson regression, spatial economics
Who is confronted to insecure labor market histories? Some evidence based on the French labor market transition
This paper presents some empirical evidence on the French labor market focusing on transitions between stable jobs, temporary work, unemployment and non-participation. The model used is based on a Markov chain mixture which allows to distinguish labor market histories that are confined to contingent work and non-employment from the non-confined ones. This enables us to identify, quantify and characterize (conditional on observable characteristics) the workers who never accede to stable jobs and remain stuck to temporary jobs and non-employment spells. We consider quarterly labor market transitions, observed from 2003 to 2006 in the Labor Force survey (LFS). We find that on the whole, about 5% of the working age population experience confined transition dynamics: they cannot access to stable jobs. Confined workers are less educated and are more likely to live in distressed areas.labor market mobility, labor market transitions, mover-stayer models, Markov chains
The impact of French Zones Franches Urbaines on employment and business creation
In 2004, 41 Zones Franches Urbaines (ZFU) have replaced less generous Zones de Redynamisation Urbaine (ZRU). ZFUs are particularly generous Enterprise Zones schemes in which establishments are exempted from all taxes and social contributions for 5 years. A first wave of ZFUs was zoned in 1997, followed by a second one in 2004 and a third one in 2006. In spite of the cost of such policies (the net cost of the second-wave ZFUs was around 125 million euros in 2005), the impact has never been assessed by econometricians. In this study, we aim to evaluate the net effect of the ZFU policy on both employment and business creations, using the transformation of less generous ZRUs into ZFUs in 2004. We use micro data on establishments and jobs at an infra-municipal scale. Differences-in-differences as well as standard propensity score matching are used to try to take selection bias into account. We finally identify a significantly positive effect on both business creations and employment. Yet, these effects are weak especially when compared to the magnitude of the costs.local employment, local policies, enterprise zones, evaluation
What kernel methods bring to the analysis of spatial concentration of migrants in France: 1968-1999
Most studies about the geographical location of a phenomenon or a population first aggregate data according to administrative boundaries which are generally not related to the issue. When the population under study is rare, and when the sample is not exhaustive, these aggregation choices often lead the results. In this study, we use non-parametric kernel techniques to estimate ratios of population densities. Using this kind of method is not technically costly and allows one to obtain the optimal trade-off between variance and bias. We apply this technique to the distribution of immigrants over the French territory, using data form population censures between 1968 to 1999. Another contribution of this work is to propose a concentration index based on the density ratios obtained in the first step.spatial concentration, geographical location, segregation indices, non-parametric estimation, immigration
Demographic change and unemployment: what do macroeconometric models predict?
Declining natality and mortality are reshaping demographic patterns in most industrialized countries. We investigate the case of France where, after a few decades of sustained growth, active population is likely to stop growing and could eventually start decreasing. This will coincide with a boom for the retired population. The purpose of this paper is to examine the consequences of both phenomena for the labour market. We tackle the issue using two approaches: WS-PS models and Phillips curve models. Effects may be short or long-run; they may stem directly from changes in labour supply or from changes in contributions required to finance pensions. In this study, we bring them altogether using the macroeconometric model MĂ©sange. We find that favorable effects can be expected in the short run. However, they are likely to be of a relatively small importance and transitory. In the medium and long run, the WS-PS framework suggests that increases in taxes induced by ageing could lead to more unemployment. This long run effect vanishes under the Phillips specification. On the whole, the final effect upon unemployment depends on agents' bargaining preferences during wage negotiations: the further from labor cost they negotiate (thus the closer to net income), the higher the risk that demographic change ultimately leads to more unemployment.ageing, labor market, macroeconomic models
Artificial Gravity Reveals that Economy of Action Determines the Stability of Sensorimotor Coordination
Background: When we move along in time with a piece of music, we synchronise the downward phase of our gesture with the beat. While it is easy to demonstrate this tendency, there is considerable debate as to its neural origins. It may have a structural basis, whereby the gravitational field acts as an orientation reference that biases the formulation of motor commands. Alternatively, it may be functional, and related to the economy with which motion assisted by gravity can be generated by the motor system
Hand use predicts the structure of representations in sensorimotor cortex.
Fine finger movements are controlled by the population activity of neurons in the hand area of primary motor cortex. Experiments using microstimulation and single-neuron electrophysiology suggest that this area represents coordinated multi-joint, rather than single-finger movements. However, the principle by which these representations are organized remains unclear. We analyzed activity patterns during individuated finger movements using functional magnetic resonance imaging (fMRI). Although the spatial layout of finger-specific activity patterns was variable across participants, the relative similarity between any pair of activity patterns was well preserved. This invariant organization was better explained by the correlation structure of everyday hand movements than by correlated muscle activity. This also generalized to an experiment using complex multi-finger movements. Finally, the organizational structure correlated with patterns of involuntary co-contracted finger movements for high-force presses. Together, our results suggest that hand use shapes the relative arrangement of finger-specific activity patterns in sensory-motor cortex
Antikinetoplastid SAR study in 3-nitroimidazopyridine series: identification of a novel non-genotoxic and potent anti-T. b. brucei hit-compound with improved pharmacokinetic properties
To study the antikinetoplastid 3-nitroimidazo[1,2-a]pyridine pharmacophore, a structure-activity relationship study was conducted through the synthesis of 26 original derivatives and their in vitro evaluation on both Leishmania spp and Trypanosoma brucei brucei. This SAR study showed that the antitrypanosomal pharmacophore was less restrictive than the antileishmanial one and highlighted positions 2, 6 and 8 of the imidazopyridine ring as key modulation points. None of the synthesized compounds allowed improvement in antileishmanial activity, compared to previous hit molecules in the series. Nevertheless, compound 8, the best antitrypanosomal molecule in this series (EC50 = 17 nM, SI = 2650 & E° = -0.6 V), was not only more active than all reference drugs and previous hit molecules in the series but also displayed improved aqueous solubility and better in vitro pharmacokinetic characteristics: good microsomal stability (T1/2 > 40 min), moderate albumin binding (77%) and moderate permeability across the blood brain barrier according to a PAMPA assay. Moreover, both micronucleus and comet assays showed that nitroaromatic molecule 8 was not genotoxic in vitro. It was evidenced that bioactivation of molecule 8 was operated by T. b. brucei type 1 nitroreductase, in the same manner as fexinidazole. Finally, a mouse pharmacokinetic study showed that 8 displayed good systemic exposure after both single and repeated oral administrations at 100 mg/kg (NOAEL) and satisfying plasmatic half-life (T1/2 = 7.7 h). Thus, molecule 8 appears as a good candidate for initiating a hit to lead drug discovery program
Motor Cortex Representation of the Upper-Limb in Individuals Born without a Hand
The body schema is an action-related representation of the body that arises from activity in a network of multiple brain areas. While it was initially thought that the body schema developed with experience, the existence of phantom limbs in individuals born without a limb (amelics) led to the suggestion that it was innate. The problem with this idea, however, is that the vast majority of amelics do not report the presence of a phantom limb. Transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1) of traumatic amputees can evoke movement sensations in the phantom, suggesting that traumatic amputation does not delete movement representations of the missing hand. Given this, we asked whether the absence of a phantom limb in the majority of amelics means that the motor cortex does not contain a cortical representation of the missing limb, or whether it is present but has been deactivated by the lack of sensorimotor experience. In four upper-limb amelic subjects we directly stimulated the arm/hand region of M1 to see 1) whether we could evoke phantom sensations, and 2) whether muscle representations in the two cortices were organised asymmetrically. TMS applied over the motor cortex contralateral to the missing limb evoked contractions in stump muscles but did not evoke phantom movement sensations. The location and extent of muscle maps varied between hemispheres but did not reveal any systematic asymmetries. In contrast, forearm muscle thresholds were always higher for the missing limb side. We suggest that phantom movement sensations reported by some upper limb amelics are mostly driven by vision and not by the persistence of motor commands to the missing limb within the sensorimotor cortex. We propose that prewired movement representations of a limb need the experience of movement to be expressed within the primary motor cortex
Gene Expression Changes in the Motor Cortex Mediating Motor Skill Learning
The primary motor cortex (M1) supports motor skill learning, yet little is known about the genes that contribute to motor cortical plasticity. Such knowledge could identify candidate molecules whose targeting might enable a new understanding of motor cortical functions, and provide new drug targets for the treatment of diseases which impair motor function, such as ischemic stroke. Here, we assess changes in the motor-cortical transcriptome across different stages of motor skill acquisition. Adult rats were trained on a gradually acquired appetitive reach and grasp task that required different strategies for successful pellet retrieval, or a sham version of the task in which the rats received pellet reward without needing to develop the reach and grasp skill. Tissue was harvested from the forelimb motor-cortical area either before training commenced, prior to the initial rise in task performance, or at peak performance. Differential classes of gene expression were observed at the time point immediately preceding motor task improvement. Functional clustering revealed that gene expression changes were related to the synapse, development, intracellular signaling, and the fibroblast growth factor (FGF) family, with many modulated genes known to regulate synaptic plasticity, synaptogenesis, and cytoskeletal dynamics. The modulated expression of synaptic genes likely reflects ongoing network reorganization from commencement of training till the point of task improvement, suggesting that motor performance improves only after sufficient modifications in the cortical circuitry have accumulated. The regulated FGF-related genes may together contribute to M1 remodeling through their roles in synaptic growth and maturation.McGovern Institute for Brain Research at MITNational Institutes of Health (U.S.) ((NIH grant 1-RC1-NS068103-01)National Institutes of Health (U.S.) (NIH grant R01-MH084966)Roberto Rocca Education Program (Fellowship)Massachusetts Institute of Technology. Undergraduate Research Opportunities Program (Fellowship)Italy. Ministero dell'istruzione, dell'università e della ricerca (MIUR grant RBIN04H5AS)Italy. Ministero dell'istruzione, dell'università e della ricerca (MIUR grant RBLA03FLJC)Italy. Ministero dell'istruzione, dell'università e della ricerca (FIRB n. RBAP10L8TY
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