Do Immigrants Cause Crime?.

We examine the empirical relationship between immigration and crime across Italian provinces during the period 1990-2003. Drawing on police administrative records, we first document that the size of the immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. Then, we use instrumental variables based on immigration toward destination countries other than Italy to identify the causal impact of exogenous changes in Italy's immigrant population. According to these estimates, immigration increases only the incidence of robberies, while leaving unaff ected all other types of crime. Since robberies represent a very minor fraction of all criminal o ffenses, the eff ect on the overall crime rate is not signi cantly di fferent from zero.crime; immigration;

Immigration and crime: an empirical analysis

In this paper we examine the empirical relationship between immigration and crime across Italian provinces during the period 1990-2003. Drawing on police data, we first document that the size of the immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. We then use instrumental variables based on migration towards other European countries to identify the causal impact of exogenous changes in the immigrant population of Italy. According to these estimates, immigration increases only the incidence of robberies and has no effect on all other types of crime. Since robberies represent a very small fraction of all criminal offences, the effect on the overall crime rate is not significantly different from zero.immigration, crime

Do immigrants cause crime?

In this paper we examine the empirical relationship between immigration and crime across Italian provinces during the period 1990-2003. Drawing on police administrative data, we first document that the size of immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. Then, we use instrumental variables based on migration toward other European countries to identify the causal impact of exogenous changes of immigrant population in Italy. According to these estimates, immigration increases only the incidence of robberies, while leaving unaffected all other types of crime. Since robberies represent a very minor fraction of all criminal offenses, the effect on the overall crime rate is not significantly different from zero.immigration ; crime

Synergy-based Hand Pose Sensing: Reconstruction Enhancement

Low-cost sensing gloves for reconstruction posture provide measurements which are limited under several regards. They are generated through an imperfectly known model, are subject to noise, and may be less than the number of Degrees of Freedom (DoFs) of the hand. Under these conditions, direct reconstruction of the hand posture is an ill-posed problem, and performance can be very poor. This paper examines the problem of estimating the posture of a human hand using(low-cost) sensing gloves, and how to improve their performance by exploiting the knowledge on how humans most frequently use their hands. To increase the accuracy of pose reconstruction without modifying the glove hardware - hence basically at no extra cost - we propose to collect, organize, and exploit information on the probabilistic distribution of human hand poses in common tasks. We discuss how a database of such an a priori information can be built, represented in a hierarchy of correlation patterns or postural synergies, and fused with glove data in a consistent way, so as to provide a good hand pose reconstruction in spite of insufficient and inaccurate sensing data. Simulations and experiments on a low-cost glove are reported which demonstrate the effectiveness of the proposed techniques.Comment: Submitted to International Journal of Robotics Research (2012

Synergy-Based Hand Pose Sensing: Optimal Glove Design

In this paper we study the problem of improving human hand pose sensing device performance by exploiting the knowledge on how humans most frequently use their hands in grasping tasks. In a companion paper we studied the problem of maximizing the reconstruction accuracy of the hand pose from partial and noisy data provided by any given pose sensing device (a sensorized "glove") taking into account statistical a priori information. In this paper we consider the dual problem of how to design pose sensing devices, i.e. how and where to place sensors on a glove, to get maximum information about the actual hand posture. We study the continuous case, whereas individual sensing elements in the glove measure a linear combination of joint angles, the discrete case, whereas each measure corresponds to a single joint angle, and the most general hybrid case, whereas both continuous and discrete sensing elements are available. The objective is to provide, for given a priori information and fixed number of measurements, the optimal design minimizing in average the reconstruction error. Solutions relying on the geometrical synergy definition as well as gradient flow-based techniques are provided. Simulations of reconstruction performance show the effectiveness of the proposed optimal design.Comment: Submitted to International Journal of Robotics Research 201

Convergence in shape of Steiner symmetrizations

There are sequences of directions such that, given any compact set K in R^n, the sequence of iterated Steiner symmetrals of K in these directions converges to a ball. However examples show that Steiner symmetrization along a sequence of directions whose differences are square summable does not generally converge. (Note that this may happen even with sequences of directions which are dense in S^{n-1}.) Here we show that such sequences converge in shape. The limit need not be an ellipsoid or even a convex set. We also deal with uniformly distributed sequences of directions, and with a recent result of Klain on Steiner symmetrization along sequences chosen from a finite set of directions.Comment: 11 page

Do Immigrants Cause Crime?

International audienceWe examine the empirical relationship between immigration and crime across Italian provinces during the period 1990-2003. Drawing on police administrative records, we first document that the size of the immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. Then, we use instrumental variables based on immigration toward destination countries other than Italy to identify the causal impact of exogenous changes in Italy's immigrant population. According to these estimates, immigration increases only the incidence of robberies, while leaving unaffected all other types of crime. Since robberies represent a very minor fraction of all criminal offenses, the effect on the overall crime rate is not significantly different from zero

Scattering higher spins off D-branes

We study scattering amplitudes of higher spin closed-string states off D-branes. For states in the `first Regge trajectory' we find remarkable simplifications both at tree level and at one loop. We discuss the high energy behavior in the Regge limit and comment on the validity of the eikonal approximation in this regime.Comment: Revised version: 22 pages, no figures, misprints corrected, references adde

Economic Crisis, Innovation Strategies and Firm Performance. Evidence from Italian Firm-level Data

Several empirical works have shown the robust and positive relation between growth and innovation at macroeconomic level and between firm economic performance and innovation at microeconomic level. However, the economists have had less opportunities to study such linkages during severe global downturns of the economic cycle. Moreover, the present disruptive economic downturn has forced the firms to implement survival strategies. One of such strategic behaviour regards the way of intervention on product and process areas through innovative actions. Focusing the attention on the micro level, the present work provides an empirical analysis on the basis of more than 500 Italian manufacturing firms located in Emilia-Romagna region, with the aim of disentangling the relations between pre-crisis innovation strategies and firm economic performance during the crisis as well as the linkages between the innovative actions taken to react to the recession's challenges and the economic performance in the recession. The results suggest the existence of strong relationships between past innovative activities and the capacity to react to the challenges brought by the crisis through innovative actions along product, process and organization/HRM dimensions, although the role of complementarities among past innovative activities does not emerge robustly. When the dependent variables are performance indicators the impact of pre-crisis innovation strategies emerges as robust for technological and organizational spheres, while intense innovative activities before the crisis on spheres like ICT, training and environment are detrimental for performances in the crisis. It seems that when the crisis hits those firms in a process of quite radical transformation and change, then the negative economic consequences of the recession are worse than in the case of firms on a more stable, less dynamic path.innovation strategies; economic crisis; firm performance