National University of La Plata

About: National University of La Plata is a education organization based out in La Plata, Argentina. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 12993 authors who have published 30013 publications receiving 495118 citations. The organization is also known as: UNLP & Universidad Nacional de La Plata.

A Distribution in Motion: The Case of Argentina

Abstract: This paper documents the changes in the income distribution in Argentina from the mid-1970s to the mid-2000s. Over the period inequality increased substantially. Two types of episodes have shaped this upward trend: deep macroeconomic crises and periods of sudden and intense economic liberalization. The sizeable rise in inequality in the 1990s seems to be associated to reallocations against unskilled-labor intensive sectors, and skilled-biased technological change within most sectors, both factors stimulated by the process of economic integration. The depth and speed of the reforms and the scarcity of public policies to ease the transition contributed to the particular severity of the income distribution changes. The macro crises and the subsequent recoveries contributed to the volatility of inequality along this upward trend. The large macroeconomic crisis of 2001/02 triggered a large jump in inequality, although income disparities returned to pre-crisis levels as the economy recovered fast, and large cash transfer programs were implemented.

Testing spatial noncommutativity via the Aharonov-Bohm effect

Abstract: The possibility of detecting noncommutative space relics is analyzed using the Aharonov-Bohm effect. We show that, if space is noncommutative, the holonomy receives nontrivial kinematical corrections that will produce a diffraction pattern even when the magnetic flux is quantized. The scattering problem is also formulated, and the differential cross section is calculated. Our results can be extrapolated to high energy physics and the bound $\ensuremath{\theta}\ensuremath{\sim}[10 \mathrm{TeV}{]}^{\ensuremath{-}2}$ is found. If this bound holds, then noncommutative effects could be explored in scattering experiments measuring differential cross sections for small angles. The bound state Aharonov-Bohm effect is also discussed.

Chromosomal aberrations in peripheral blood lymphocytes from native Andean women and children from Northwestern Argentina exposed to arsenic in drinking water

Abstract: For conducting an adequate human cancer risk assessment of inorganic arsenic (As) in the low-dose region, it is important to establish its mode of action. In this context, the nature of genotoxic effects induced by this agent is of considerable interest. However, the results from such investigations in human have been conflicting. In an attempt to resolve this issue, the clastogenic and aneugenic potential of As was investigated in women and children from native population exposed to high levels (around 0.2 mg/l) of natural As via drinking water in San Antonio de los Corbes in the Andean region of Salta, Northwestern Argentina. The water did not contain elevated levels of heavy metals, such as lead or cadmium, nor was the investigated population exposed to significant industrial pollution or to pesticides. An ethnically similar control group from Rosario de Lerma, Salta, where only extremely low concentration of arsenic in drinking water could be detected, was used as a control. To evaluate the genotoxic effects in peripheral blood lymphocytes, micronuclei (MN) in binucleated cells, sister-chromatid exchanges (SCEs) and the fluorescence in situ hybridization technique (FISH) in combination with chromosome specific DNA libraries were employed. The data obtained clearly indicate a highly significant increase in the frequency of MN and of trisomy in lymphocytes from exposed children and women in comparison with controls, but no notable effects were found on the frequencies of SCEs, specific translocations, or on cell cycle progression. As supported by FISH analysis, at least a proportion of MN appears to originate from whole chromosome loss. An additional finding was the unusually low background levels of MN in unexposed individuals from this ethnic group as compared to other populations, e.g., Caucasians.

Spiral Structure in the Outer Galactic Disk. I. The Third Galactic Quadrant

Abstract: Fil: Vazquez, Ruben Angel. Universidad Nacional de La Plata. Facultad de Ciencias Astronomicas y Geofisicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Astrofisica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronomicas y Geofisicas. Instituto de Astrofisica La Plata; Argentina

Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation

Abstract: The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remain contentious, with major phases coinciding with both human arrival and climate change around the world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately, limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon data sets from the region. We identify a narrow megafaunal extinction phase 12,280 ± 110 years ago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediately prior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence and climate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts.