ILASSA: From Brown Bags to Soccer

Latin American Studie

New Results on the Effects of Tax Policy on the International Location of Investment

We study the effects of tax laws on foreign direct investment (FDI) and direct investment abroad (DIA), distinguishing in each case between investment financed by retained earnings and investment financed by transfers from abroad. We find that tax policy, through its effect on the rate-of-return available in the U.S., has an important effect on the international location of investment. FDI in the U.S. is very sensitive to after-tax rates-of-return available here. U.S. direct investment abroad is also affected, although to a lesser extent. We use these estimates to examine the effects of the 1981-82 tax changes on the international location of investment. We estimate that the tax changes lowered annual DIA by $0.5 billion to$1.0 billion (2% to 4% of its 1980 value), and raised annual FDI by $2 billion to$4 billion (11% of 20% of its 1980 value). We also discuss the welfare effects of tax policy toward international investment. Our results suggest that the tax effects on the international location of investment are important. Tax policies, such as ACRS andthe ITC, which raise the after tax rate-of-return on new investment without losing revenue from previous investment, not only stimulate domestic fixed investment, but also attract additional investment from abroad. The additional investment supplements the domestic investment impact on productivity and raises corporate tax revenue. However, our results should be taken as preliminary estimates, not as definitive statements about the long-run impacts of tax policy.

MAVS expressed by hematopoietic cells is critical for control of West Nile virus infection and pathogenesis

West Nile virus (WNV) is the most important cause of epidemic encephalitis in North America. Innate immune responses, which are critical for control of WNV infection, are initiated by signaling through pathogen recognition receptors, RIG-I and MDA5, and their downstream adaptor molecule, MAVS. Here, we show that a deficiency of MAVS in hematopoietic cells resulted in increased mortality and delayed WNV clearance from the brain. In Mavs(−/−) mice, a dysregulated immune response was detected, characterized by a massive influx of macrophages and virus-specific T cells into the infected brain. These T cells were polyfunctional and lysed peptide-pulsed target cells in vitro. However, virus-specific T cells in the brains of infected Mavs(−/−) mice exhibited lower functional avidity than those in wild-type animals, and even virus-specific memory T cells generated by prior immunization could not protect Mavs(−/−) mice from WNV-induced lethal disease. Concomitant with ineffective virus clearance, macrophage numbers were increased in the Mavs(−/−) brain, and both macrophages and microglia exhibited an activated phenotype. Microarray analyses of leukocytes in the infected Mavs(−/−) brain showed a preferential expression of genes associated with activation and inflammation. Together, these results demonstrate a critical role for MAVS in hematopoietic cells in augmenting the kinetics of WNV clearance and thereby preventing a dysregulated and pathogenic immune response. IMPORTANCE West Nile virus (WNV) is the most important cause of mosquito-transmitted encephalitis in the United States. The innate immune response is known to be critical for protection in infected mice. Here, we show that expression of MAVS, a key adaptor molecule in the RIG-I-like receptor RNA-sensing pathway, in hematopoietic cells is critical for protection from lethal WNV infection. In the absence of MAVS, there is a massive infiltration of myeloid cells and virus-specific T cells into the brain and overexuberant production of proinflammatory cytokines. These results demonstrate the important role that MAVS expression in hematopoietic cells has in regulating the inflammatory response in the WNV-infected brain

Photoevoked response of the optic tectum in larval stage XII and juvenile Rana catesbeiana

The previous cytological and electrophysiological work suggests that the optic tectum matures during metamorphic climax. It was the aim of the present work to attempt to compare pre metamorphic (Stage XII) larval and post metamorphic juvenile, Rana catesbeiana, using a photostimulated evoked electroencephalographic (E.E.G.) response in the optic tectum and correlate that with tissue studies to verify neurophysiological maturation of the optic tectum

Infrared Dynamics of a Large N QCD Model, the Massless String Sector and Mesonic Spectra

A consistency check for any UV complete model for large N QCD should be, among other things, the existence of a well-defined vector and scalar mesonic spectra. In this paper, we use our UV complete model in type IIB string theory to study the IR dynamics and use this to predict the mesonic spectra in the dual type IIA side. The advantage of this approach is two-fold: not only will this justify the consistency of the supergravity approach, but it will also give us a way to compare the IR spectra and the model with the ones proposed earlier by Sakai and Sugimoto. Interestingly, the spectra coming from the massless stringy sector are independent of the UV physics, although the massive string sector may pose certain subtleties regarding the UV contributions as well as the mappings to actual QCD. Additionally, we find that a component of the string landscape enters the picture: there are points in the landscape where the spectra can be considerably improved over the existing results in the literature. These points in the landscape in-turn also determine certain background supergravity components and fix various pathologies that eventually lead to a consistent low energy description of the theory.Comment: 47 pages, 7 pdf figures, 24 tables, JHEP format; Detailed mathematica file of the computations is available on request; Version 2: Text elaborated, typos corrected, a new appendix added to discuss the regimes of validity, and a word in the abstract changed. Results unchanged. Final version to appear in JHE

Analyzing the on Source Window of Supernova SN2019EJJ With a Multi Layered Signal Enhancement Algorithm With Coherent Waveburst and a Convolutional Neural Network

Core collapse supernovae (CCSN) are highly anticipated sources of gravitational waves during the fourth observation run (O4). CCSN signals are weak and unmodeled and the rate of occurrence in our galaxy is very low. Because of this, they provide a greater challenge to detect than previously detected GW sources. CCSN simulations are used to test the detection pipeline in the event a CCSN is detected. CCSN GW signals are often indistinguishable from the noise sources present in GW data. We present a multi layered signal enhancement pipeline which we have applied Machine Learning (ML) techniques. We have used a Convolutional Neural Network (CNN) to train on 10 different simulated CCSN signals, and then tested the preformance of our pipeline on rotating CCSN signals

Statistics of stable marriages

In the stable marriage problem N men and N women have to be matched by pairs under the constraint that the resulting matching is stable. We study the statistical properties of stable matchings in the large N limit using both numerical and analytical methods. Generalizations of the model including singles and unequal numbers of men and women are also investigated.Comment: 7 pages, 6 figures; to appear in Physica

Meta-genetic programming for static quantum circuits

Quantum programs are difficult for humans to develop due to their complex semantics that are rooted in quantum physics. It is there- fore preferable to write specifications and then use techniques such as genetic programming (GP) to generate quantum programs in- stead. We present a new genetic programming system for quantum circuits which can evolve solutions to the full-adder and quantum Fourier transform problems in fewer generations than previous work, despite using a general set of gates. This means that it is no longer required to have any previous knowledge of the solution and choose a specialised gate set based on it