Erosion rates in subtropical, rapidly developing countries: an isotopic approach to measuring background rates of erosion in Brazil and China

Erosion, a surface process, can be quantified over long-term (assumed to be the natural erosion rate of the landscape) and contemporary (modern) timeframes. My research used the rare cosmogenic isotope 10Be in sand and cobbles collected from rivers in southeastern Brazil (Santa Catarina and Rio de Janeiro states) and southwestern China (Yunnan province) to quantify long-term, background rates of erosion and sediment supply. These measurements will also increase number of such measurements in tropical and subtropical climates. I assessed the relationship between landscape parameters (topographic and climatic) and background erosion rates in order to understand factors related to erosion. My data from so far unsampled states in Brazil shows that background erosion rates range between 13 and 90 m/Myr. I found that mean basin slope (R2=0.73) and mean annual precipitation (R2=0.57) are strongly correlated to erosion rates. Steep, escarpment-draining basins in Brazil erode faster than lower gradient basins draining the highlands. Comparing the isotopic concentration of river sand and cobbles, my data show that these grain sizes are sourced from different parts of the landscape. I compiled all published Brazilian cosmogenic 10Be data, and compared them to erosion rates from similar tectonic settings. While the erosion rates in Brazil are relatively low, they are similar to those in southeastern North America, but faster than rates measured on escarpments in southern Africa. In China, I tested the human effects on denudation by comparing long-term erosion rates derived from in-situ 10Be concentration and the modern sediment yield of 22 watersheds in Yunnan. Background erosion rates range between 17 and 386 m/Myr; long term sediment yields based on these erosion rates range from 79 to 893 tons km-2 yr-1. Modern sediment yields range from 90 to 2,879 tons km-2 yr-1 (data from Schmidt et al., 2011). In most watersheds, the modern sediment yield is 2-3X higher than long-term rates, likely the effect of a long history of land use in Yunnan. I found a statistically significant, positive relationship between erosion rates and both area (R2 = 0.60) and mean basin slope (R2 = 0.42). There is a negative but strong relationship between erosion rates and precipitation in my dataset (R2 = 0.60). I sampled some places where 10Be samples had been collected before to test the methodological assumption of time-invariant 10Be concentration. Concentrations generally agree on samples taken 6 months apart and in samples from the active channel and from floodplains, but not in samples collected a decade and centuries apart

Origins of the Commonwealth of Puerto Rico in the Context of United States Strategic Interests in the Caribbean (1938-1950)

The purpose of this paper is to explore the political and military considerations that provided the frame of reference for the promulgation of the Commonwealth of Puerto Rico in 1952. Since 1492 possession of this island has been coveted by nations with vital interest in the Caribbean region. To the United States, who conquered the island in 1898, Puerto Rico formed the backbone of the defense perimeter for the Panama Canal and adjacent shipping lanes. Experience during World War 11 and the subsequent threat from the Soviet Union reinforced the military value of the island. The importance of the geostrategic location of the island to the United States was the crucial factor that determined the type of political system that substituted fifty years of U.S. colonial rule with a measure of self-government. The leadership of Luis Munoz Marin and the moderate ideology of his Partido Popular Democratico (Popular Democratic Party) proved to be the best vehicle for the implementation of the reforms that would guarantee both the preservation of U.S. sovereignty over Puerto Rico and the improvement of the welfare of the people of the island

Gene expression rearrangements denoting changes in the biological state

In many situations, the gene expression signature is a unique marker of the biological state. We study the modification of the gene expression distribution function when the biological state of a system experiences a change. This change may be the result of a selective pressure, as in the Long Term Evolution Experiment with E. Coli populations, or the progression to Alzheimer disease in aged brains, or the progression from a normal tissue to the cancer state. The first two cases seem to belong to a class of transitions, where the initial and final states are relatively close to each other, and the distribution function for the differential expressions is short ranged, with a tail of only a few dozens of strongly varying genes. In the latter case, cancer, the initial and final states are far apart and separated by a low-fitness barrier. The distribution function shows a very heavy tail, with thousands of silenced and over-expressed genes. We characterize the biological states by means of their principal component representations, and the expression distribution functions by their maximal and minimal differential expression values and the exponents of the Pareto laws describing the tails

Impactos socioculturales del turismo en el Centro Integralmente Planeado Loreto, Baja California Sur, México. Percepción de los residentes locales

Con el argumento de que una actitud favorable depende de la percepción positiva del turismo, se presenta un reporte de investigación en el que se identificaron los impactos positivos (o beneficios) y los negativos (o costos) ocasionados por el turismo, según la percepción de los residentes del Centro Integralmente Planeado (cip) Loreto, en Baja California, México. Con una combinación de técnicas cualitativas y cuantitativas se comprobó que los habitantes del cip Loreto perciben más beneficios que costos, sobre todo en las oportunidades de empleo generadas y en la implementación de más y mejor infraestructura y servicios que, si bien son realizados para los turistas, también son disfrutados por los residentes. Por el volumen de turistas, los efectos negativos aún no son patentes para la mayoría, pero algunos prestadores de servicios turísticos perciben como “desleal” la competencia que representan los turistas de segunda residencia en el lugar

Neural Connectivity with Hidden Gaussian Graphical State-Model

The noninvasive procedures for neural connectivity are under questioning. Theoretical models sustain that the electromagnetic field registered at external sensors is elicited by currents at neural space. Nevertheless, what we observe at the sensor space is a superposition of projected fields, from the whole gray-matter. This is the reason for a major pitfall of noninvasive Electrophysiology methods: distorted reconstruction of neural activity and its connectivity or leakage. It has been proven that current methods produce incorrect connectomes. Somewhat related to the incorrect connectivity modelling, they disregard either Systems Theory and Bayesian Information Theory. We introduce a new formalism that attains for it, Hidden Gaussian Graphical State-Model (HIGGS). A neural Gaussian Graphical Model (GGM) hidden by the observation equation of Magneto-encephalographic (MEEG) signals. HIGGS is equivalent to a frequency domain Linear State Space Model (LSSM) but with sparse connectivity prior. The mathematical contribution here is the theory for high-dimensional and frequency-domain HIGGS solvers. We demonstrate that HIGGS can attenuate the leakage effect in the most critical case: the distortion EEG signal due to head volume conduction heterogeneities. Its application in EEG is illustrated with retrieved connectivity patterns from human Steady State Visual Evoked Potentials (SSVEP). We provide for the first time confirmatory evidence for noninvasive procedures of neural connectivity: concurrent EEG and Electrocorticography (ECoG) recordings on monkey. Open source packages are freely available online, to reproduce the results presented in this paper and to analyze external MEEG databases

Editorial: Social networks analyses in primates, a multilevel perspective

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La divulgación ambiental frente al cambio climático en la provincia de Camagüey, Cuba

Climate change ranks as one of the major global challenges at the present time, which dictates the intensification of adaptation and mitigation measures, according the degree of vulnerability and risk in the short, medium and long periods, depending on the characteristics of each place; hence advertising in this direction not escape the changing environment, in contrast with much acuity should think what to do. This paper addresses the role of the media in the dissemination of environmental issues, explores organizational and structural mediations, the cognitives and the external factors in information processing with emphasis on addressing natural disasters and the effects of climate change in their relationship with the receiver or public to which the communication products and the context in which these actions are performed are headed. Results of a descriptive qualitative research-oriented to the characterization of the production process of the media are synthesized.El cambio climático está considerado como uno de los principales desafíos a nivel global en los momentos actuales; lo que impone que se incrementen las medidas de adaptación y mitigación, en correspondencia con los peligros, el grado de vulnerabilidad y los riesgos a corto, mediano y largo plazos, dependiendo de las características de cada lugar; de ahí que en esta dirección la publicidad no escape a los cambios del entorno. Por el contrario, debe pensarse con mucha agudeza qué hacer. El presente trabajo aborda el papel que pueden desempeñar los medios de comunicación masiva en la divulgación de temas ambientales, profundiza en las mediaciones estructurales organizativas, cognitivas y los factores externos en el tratamiento de la información, con énfasis en el abordaje de los desastres naturales y los efectos del cambio climático, en su relación con los receptores o públicos hacia los cuales se dirigen los productos comunicativos y el contexto en el que se realizan estas acciones. Se sintetizan resultados de una investigación descriptiva orientada hacia la caracterización cualitativa del proceso de producción de los medios de difusión