High field magneto-transport in high mobility gated InSb/InAlSb quantum well heterostructures

We present high field magneto-transport data from a range of 30nm wide InSb/InAlSb quantum wells. The low temperature carrier mobility of the samples studied ranged from 18.4 to 39.5 m2V-1s-1 with carrier densities between 1.5x1015 and 3.28x1015 m-2. Room temperature mobilities are reported in excess of 6 m2V-1s-1. It is found that the Landau level broadening decreases with carrier density and beating patterns are observed in the magnetoresistance with non-zero node amplitudes in samples with the narrowest broadening despite the presence of a large g-factor. The beating is attributed to Rashba splitting phenomenon and Rashba coupling parameters are extracted from the difference in spin populations for a range of samples and gate biases. The influence of Landau level broadening and spin-dependent scattering rates on the observation of beating in the Shubnikov-de Haas oscillations is investigated by simulations of the magnetoconductance. Data with non-zero beat node amplitudes are accompanied by asymmetric peaks in the Fourier transform, which are successfully reproduced by introducing a spin-dependent broadening in the simulations. It is found that the low-energy (majority) spin up state suffers more scattering than the high-energy (minority) spin down state and that the absence of beating patterns in the majority of (lower density) samples can be attributed to the same effect when the magnitude of the level broadening is large

The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD: a monozygotic twin study

BACKGROUND: PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD. METHODS: Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins. RESULTS: There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD. CONCLUSIONS: These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.Timothy Hall, Cherrie Galletly, C.R. Clark, Melinda Veltmeyer, Linda J. Metzger, Mark W. Gilbertson, Scott P. Orr, Roger K. Pitman and Alexander McFarlan

Mapping aerial metal deposition in metropolitan areas from tree bark : a case study in Sheffield, England

We investigated the use of metals accumulated on tree bark for mapping their deposition across metropolitan Sheffield by sampling 642 trees of three common species. Mean concentrations of metals were generally an order of magnitude greater than in samples from a remote uncontaminated site. We found trivially small differences among tree species with respect to metal concentrations on bark, and in subsequent statistical analyses did not discriminate between them. We mapped the concentrations of As, Cd and Ni by lognormal universal kriging using parameters estimated by residual maximum likelihood ({\sc reml}). The concentrations of Ni and Cd were greatest close to a large steel works, their probable source, and declined markedly within 500~metres of it and from there more gradually over several kilometres. Arsenic was much more evenly distributed, probably as a result of locally mined coal burned in domestic fires for many years. Tree bark seems to integrate airborne pollution over time, and our findings show that sampling and analysing it are cost-effective means of mapping and identifying sources

Young people, crime and school exclusion: a case of some surprises

During the 1990s the number of young people being permanently excluded from schools in England and Wales increased dramatically from 2,910 (1990/91) to a peak of 12,700 (1996/97). Coinciding with this rise was a resurgence of the debate centring on lawless and delinquent youth. With the publication of Young People and Crime (Graham and Bowling 1995) and Misspent Youth (Audit Commission 1996) the 'common sense assumption' that exclusion from school inexorably promoted crime received wide support, with the school excludee portrayed as another latter day 'folk devil'. This article explores the link between school exclusion and juvenile crime, and offers some key findings from a research study undertaken with 56 young people who had experience of being excluded from school. Self-report interview questions reveal that whilst 40 of the young people had offended, 90% (36) reported that the onset of their offending commenced prior to their first exclusion. Moreover, 50 (89.2% of the total number of young people in the sample), stated that they were no more likely to offend subsequent to being excluded and 31 (55.4%) stated that they were less likely to offend during their exclusion period. Often, this was because on being excluded, they were 'grounded' by their parents

Greening Capitalism? A Marxist Critique of Carbon Markets

Climate change is increasingly being recognized as a serious threat to dominant modes of social organization, inspiring suggestions that capitalism itself needs to be transformed if we are to ‘decarbonize’ the global economy. Since the Kyoto Protocol in 1997, carbon markets have emerged as the main politico-economic tools in global efforts to address climate change. Newell and Paterson (2010) have recently claimed that the embrace of carbon markets by financial and political elites constitutes a possible first step towards the transformation of current modes of capitalist organization into a new form of greener, more sustainable ‘climate capitalism.’ In this paper, we argue that the institutionalization of carbon markets does not, in fact, represent a move towards the radical transformation of capitalism, but is better understood as the most recent expression of ongoing trends of ecological commodification and expropriation, driving familiar processes of uneven and crisis-prone development. In this paper, we review four critical Marxist concepts: metabolic rift (Foster, 1999), capitalism as world ecology (Moore, 2011a), uneven development and accumulation through dispossession (Harvey, 2003, 2006), and sub-imperialism (Marini, 1972, 1977), developing a framework for a Marxist analysis of carbon markets. Our analysis shows that carbon markets form part of a longer historical development of global capitalism and its relation to nature. Carbon markets, we argue, serve as creative new modes of accumulation, but are unlikely to transform capitalist dynamics in ways that might foster a more sustainable global economy. Our analysis also elucidates, in particular, the role that carbon markets play in exacerbating uneven development within the Global South, as elites in emerging economies leverage carbon market financing to pursue new strategies of sub-imperial expansion. </jats:p

An Intercomparison of Evapotranspiration Estimation Methods for the Godomey Well Field in Benin, West Africa

The Godomey well field supplies groundwater for Cotonou, the largest city in Benin, West Africa. Due to the proximity of the wells to the Atlantic Ocean (5 km north of the ocean) and to Lake Nokoué, a shallow lake with high levels of chloride, the wells are threatened by saltwater intrusion. Ongoing efforts aim to characterize this groundwater system to provide management and sustainability information. As part of this effort, the goal of this study was to determine whether remote sensing of evapotranspiration provides a unique alternative to overcome data limitations of modeling in a developing country. This study utilized three methods to estimate evapotranspiration (ET) for use in an existing groundwater model for the area. ET methods included: a crop coefficient method that used remotely sensed Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), Complementary Relationship Areal Evapotranspiration (CRAE), and evapotranspiration from the Noah Land Surface Model (LSM) provided in the Global Land Data Assimilation System (GLDAS). The CRAE model estimated the highest ET in the study area for the years 2001-2010. The Noah LSM estimated the lowest ET, while the MODIS NDVI crop coefficient method provided intermediate ET estimates. Although the methods varied in magnitude of ET, timing of seasonal changes in ET was consistent for the three methods and reflected the weather variation in the study area. The MODIS NDVI crop coefficient method is practical for use in developing countries because it requires few data inputs, uses accessible satellite data, has a low cost, and is relatively simple to apply.The final products of this research include spatially distributed actual ET for the groundwater model study area at monthly intervals from 2001-2010. Preliminary calculations utilizing limited precipitation data suggest that the study area may be a zone of net groundwater discharge, with some recharge occurring near the coast and Lake Nokoué. The ET products created in this study are intended for future use with runoff and precipitation data to determine spatially distributed recharge or discharge for the groundwater model. The MODIS NDVI crop coefficient method provides a unique opportunity for improving hydrologic budgets in developing communities that are data limited

Globalization and the Sex Trafficking Industry: Examination of Effects on Regional Value Chain Operations

The purpose of this paper is to examine sex trafficking as a profitable, international, and illegal industry. One goal of this paper is to explain what sex trafficking is and how it differs from other industries. Sex trafficking is an underground activity and its growth worldwide since the 1980s has had a destructive impact on global societies and economies. Beyond this, the study wants to show that, aside from moral and socio-cultural implications, that sex trafficking is indeed an industry, with a structure not so different from other industries. Understanding sex trafficking as an industry is critical to understanding how it operates, why it has the impact it has in the world, and what global strategies can be developed to effectively fight it. To do this, the paper shows how the value chain concept, so critical in analyzing other industries, is appropriate to understanding the mechanisms at work in sex trafficking. The study further shows that cultural and social differences play a major role in how the value chain operates within different countries and that these differences must be taken into account and dealt with when governments and public policy strategize ending –or at least easing—the grip of sex trafficking on society. This will be shown by examining the value chains of the United States and India respectively in order to show apparent differences in the regional functioning of sex trafficking

Marie and Robert Jackson Fellows: Office of Senator Al Franken

This poster outlines what federal senators can do; my responsibilities as an intern; and the experience gained through this fellowship

Women and the Equal Protection Clause

The stance of the law in this respect, as with other social trends, has generally reflected the current attitudes that dominate the society it governs. Yet, as late as 1969, we still had judges on the appellate level taking judicial notice of the female\u27s lesser capacity for sexual arousal, the sexual behavior of the vast majority of women in a civilized society, and the normal behavior of a married woman in the presence of her husband in their bedroom;\u27 all in a puritanically paternalistic fashion. This, and other absurd judicial pronouncements may have been what prompted one controversial attorney to observe that all ostriches do not have feathers and a beak

Characterizations of how species mediate ecosystem properties require more comprehensive functional effect descriptors

The importance of individual species in mediating ecosystem process and functioning is generally accepted, but categorical descriptors that summarize species-specific contributions to ecosystems tend to reference a limited number of biological traits and underestimate the importance of how organisms interact with their environment. Here, we show how three functionally contrasting sediment-dwelling marine invertebrates affect fluid and particle transport - important processes in mediating nutrient cycling - and use high-resolution reconstructions of burrow geometry to determine the extent and nature of biogenic modification. We find that individual functional effect descriptors fall short of being able to adequately characterize how species mediate the stocks and flows of important ecosystem properties and that, in contrary to common practice and understanding, they are not substitutable with one another because they emphasize different aspects of species activity and behavior. When information derived from these metrics is combined with knowledge of how species behave and modify their environment, however, detailed mechanistic information emerges that increases the likelihood that a species functional standing will be appropriately summarized. Our study provides evidence that more comprehensive functional effect descriptors are required if they are to be of value to those tasked with projecting how altered biodiversity will influence future ecosystems