Bosonic and fermionic Weinberg-Joos (j,0)+ (0,j) states of arbitrary spins as Lorentz-tensors or tensor-spinors and second order theory

We propose a general method for the description of arbitrary single spin-j states transforming according to (j,0)+(0,j) carrier spaces of the Lorentz algebra in terms of Lorentz-tensors for bosons, and tensor-spinors for fermions, and by means of second order Lagrangians. The method allows to avoid the cumbersome matrix calculus and higher \partial^{2j} order wave equations inherent to the Weinberg-Joos approach. We start with reducible Lorentz-tensor (tensor-spinor) representation spaces hosting one sole (j,0)+(0,j) irreducible sector and design there a representation reduction algorithm based on one of the Casimir invariants of the Lorentz algebra. This algorithm allows us to separate neatly the pure spin-j sector of interest from the rest, while preserving the separate Lorentz- and Dirac indexes. However, the Lorentz invariants are momentum independent and do not provide wave equations. Genuine wave equations are obtained by conditioning the Lorentz-tensors under consideration to satisfy the Klein-Gordon equation. In so doing, one always ends up with wave equations and associated Lagrangians that are second order in the momenta. Specifically, a spin-3/2 particle transforming as (3/2,0)+ (0,3/2) is comfortably described by a second order Lagrangian in the basis of the totally antisymmetric Lorentz tensor-spinor of second rank, \Psi_[ \mu\nu]. Moreover, the particle is shown to propagate causally within an electromagnetic background. In our study of (3/2,0)+(0,3/2) as part of \Psi_[\mu\nu] we reproduce the electromagnetic multipole moments known from the Weinberg-Joos theory. We also find a Compton differential cross section that satisfies unitarity in forward direction. The suggested tensor calculus presents itself very computer friendly with respect to the symbolic software FeynCalc.Comment: LaTex 34 pages, 1 table, 8 figures. arXiv admin note: text overlap with arXiv:1312.581

A Role for Sunspots in Explaining Endogenous Fluctutations in Illegal Immigration

In this paper we provide an alternative explanation for why illegal immigration can exhibit substantial fluctuations despite a constant wage gap. We develop a model economy in which migrants make decisions in the face of uncertain border enforcement and lump-sum transfers from the host country. The uncertainty is extrinsic in nature, a sunspot, and arises as a result of ambiguity regarding the commodity price of money. Migrants are restricted from participating in state-contingent insurance markets in the host country, whereas host country natives are not. We establish the existence of sunspot equilibria that are not mere randomizations over certainty equilibria. Volatility in migration flows stems from two distinct sources: the tension between transfers inducing migration and enforcement discouraging it and secondly the existence of a sunspot. Finally, we examine the impact of a change in tax/transfer policies by the government on migration.Sunspots, Immigration, International Migration

Coyote crossings: the role of smugglers in illegal immigration and border enforcement

Illegal immigration and border enforcement in the United States have increased concomitantly for over thirty years. One interpretation is that U.S. border policies have been ineffective. We offer an alternative view, extending the current immigration-enforcement literature by incorporating both the practice of people smuggling and a role for non-wage income into a two-country, dynamic general equilibrium model. We state conditions under which two steady state equilibria exist: one with a low level of capital, but relatively little migration. We then analyze two shocks: a positive technology shock to smuggling services and an increase in border enforcement. In the low-capital steady state, the capital-labor ratio declines with technological progress in smuggling, while illegal immigration increases. In the high-capital steady state, a technology shock causes the capital-labor ratio to rise while the effect on migration is indeterminate. We show that an increase in border enforcement is qualitatively equivalent to a negative technology shock to smuggling. Finally, we show that a developed country would never choose small levels of border enforcement over an open border. Moreover, a high level of border enforcement is optimal only if it significantly decreases capital accumulation. In addition, we provide conditions under which an increase in smuggler technology will lead to a decline in the optimal level of enforcement.Emigration and immigration ; Mexico

THE EFFECTS OF QUORUM SENSING ANTAGONISTS ON BIOFILM

poster abstractCystic fibrosis (CF) is a recessive genetic disorder that causes the for-mation of thick mucus plugs in the lungs of approximately 30,000 people in the United States and 60,000 individuals world-wide. Pseudomonas aeruginosa, an opportunistic bacterial pathogen, is able to colonize the mu-cus plugs and form antibiotic resistant biofilms. These microbial colonies, known as biofilms, cause serious problems for individuals living with CF. P. aeruginosa biofilms are able to cause chronic infections in the lungs of CF patients leading to increased morbidity and mortality. Using a modified bio-film assay, we tested the effects of modified chemical compounds and amino acids on P. aeruginosa biofilm dispersion. A previous study performed on P. aeruginosa, found that treatment of d- and l- amino acids resulted in biofilm dissemination. Through additional experiments, we will identify modified chemical compounds that induce biofilm dispersion. This research will in-crease our knowledge of P. aeruginosa biofilm dispersion, and allow us to explore new forms of treatment and therapy for CF patients with chronic in-fections that could be life threatening

Migranti per amore. Rinunce, risorse e opportunità nell’espatrio femminile dal Messico all’Italia

Il fenomeno dell’espatrio femminile ha assunto solo in tempi recenti specifiche ed interessanti sfaccettature. I dati ISTAT (2007) sui matrimoni in Italia mostrano un incremento considerevole dei matrimoni misti. Partendo dall’ipotesi che la migrazione dovuta al progetto di vita con un partner straniero è un processo che mobilita cambiamenti interni e costringe a ristrutturare l’identità, questo lavoro ha come obiettivo di analizzare le modalità di narrazione con cui 12 donne messicane ri-costruiscono e dotano di senso la loro esperienza di espatrio in Italia. Il corpus costituito dalle interviste narrative è stato sottoposto a diverse analisi, semantico-strutturale (Alceste) e categoriale-tematica (N-Vivo). I risultati mostrano che le donne immigrate per amore rinunciano a parti di Sé e soprattutto della loro identità sociale e professionale, ma sviluppano modalità di comportamento resilienti, frutto di un’esperienza “ponte” complessa, che tuttavia il paese di accoglienza raramente supporta. The phenomenon of women expatriation has only recently taken specific and interesting facets. ISTAT data (2007) on weddings in Italy show a considerable increase in mixed marriages. Assuming that the migration due to the project of life with a foreign partner is a process that mobilizes internal changes and forces to restructure their identity, this work aims to study the ways of storytelling in which 12 Mexican women re-build and give meaning to their experience of expatriation to Italy. The corpus, consistent of narrative interviews, was subjected to various analysis, semantic-structural (Alceste) and categorical thematic-(N-Vivo). The data show that women emigrant for love give up parts of themselves and especially their social and professional identity, but develop resilient mode of behavior as a result of a complex bridging experience, but this is rarely supported by the host country

Coyote Crossings: The Role of Smugglers in Illegal Immigration and Border Enforcement

Illegal immigration and border enforcement in the United States have increased concomitantly for over thirty years. One interpretation is that U.S. border policies have been ineffective. We offer an alternative view, extending the current immigration-enforcement literature by incorporating both the practice of people smuggling and a role for non-wage income into a two- country, dynamic general equilibrium model. We state conditions under which two steady state equilibria exist: one with a low level of capital and high amount of illegal immigration and the other with a high level of capital, but relatively little migration. We then analyze two shocks: a positive technology shock to smuggling services and an increase in border enforcement. In the low-capital steady state, the capital-labor ratio declines with technological progress in smuggling, while illegal immigration increases. In the high-capital steady state, a technology shock causes the capital-labor ratio to rise while the effect on migration is indeterminate. We show that an increase in border enforcement is qualitatively equivalent to a negative technology shock to smuggling. Finally, we show that a developed country would never chose small levels of border enforcement over an open border. Moreover, a high level of border enforcement is optimal only if it significantly decreases capital accumulation. In addition we provide conditions under which an increase in smuggler technology will lead to a decline in the optimal level of enforcement

Probing the Super Star Cluster Environment of NGC 1569 Using FISICA

We present near-IR JH spectra of the central regions of the dwarf starburst galaxy NGC 1569 using the Florida Image Slicer for Infrared Cosmology and Astrophysics (FISICA). The dust-penetrating properties and available spectral features of the near-IR, combined with the integral field unit (IFU) capability to take spectra of a field, make FISICA an ideal tool for this work. We use the prominent [He I] (1.083\mu m) and Pa\beta (1.282 \mu m) lines to probe the dense star forming regions as well as characterize the general star forming environment around the super star clusters (SSCs) in NGC 1569. We find [He I] coincident with CO clouds to the north and west of the SSCs, which provides the first, conclusive evidence for embedded star clusters here.Comment: 6 pages, 3 figures, accepted for publication in the MNRA

A Role for Sunspots in Explaining Endogenous Fluctutations in Illegal Immigration

In this paper we provide an alternative explanation for why illegal immigration can exhibit substantial fluctuations despite a constant wage gap. We develop a model economy in which migrants make decisions in the face of uncertain border enforcement and lump-sum transfers from the host country. The uncertainty is extrinsic in nature, a sunspot, and arises as a result of ambiguity regarding the commodity price of money. Migrants are restricted from participating in state-contingent insurance markets in the host country, whereas host country natives are not. We establish the existence of sunspot equilibria that are not mere randomizations over certainty equilibria. Volatility in migration flows stems from two distinct sources: the tension between transfers inducing migration and enforcement discouraging it and secondly the existence of a sunspot. Finally, we examine the impact of a change in tax/transfer policies by the government on migratio

Accounting for Fluctuations in Social Network Usage and Migration Dynamics

In this paper, we examine network capital usage and migration patterns in a theoretical model. Networks are modeled as impacting the migration decision in many ways. When young, larger networks reduce the time lost moving from one region to another. In addition networks decrease the time spent searching for a job. Finally, when old, migrants receive transfer payments through the network. We show that the number and properties of steady state equilibria as well as the global dynamics depend crucially on whether the returns to network capital accumulation exhibit constant, increasing, or decreasing returns to scales relative to the level of network capital. With constant returns to scale, migration flows and network capital levels are characterized by either a unique steady state equilibria or by a two-period cycle. The fluctuations in network capital usage exhibited by our model are consistent with recent empirical data regarding the usage of networks by Mexican immigrants. In the case of increasing returns to scale, either there exists a unique, stable steady state equilibria or multiple equilibria which are characterized as either sinks or saddles. When the returns to scale are decreasing, there exists a unique, stable steady state equilibrium. Finally, we show that increasing barriers to migration will result in an increase in the flow of immigrants, contrary to the desired effect, in the constant and increasing returns to scale cases