896 resultados para Arsenic mobility


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Despite the widespread interest in the topic and a vast international literature, only little is known about the development of intergenerational mobility in Switzerland. Based on a new harmonized database for Switzerland (comprising various surveys such as different waves of the ISSP, EVS, or the ESS), we provide a systematic account of changes in the link between social origin and destination over time (covering birth cohorts from 1940 through 1980). We analyze effects of parental education and class on own educational achievement and social class for both men and women, using a refined variant of the methodological approach proposed by Jann and Combet (2012). The approach is based on the concept of proportional reduction of error (PRE) and features a number of advantages over more traditional approaches. For example, it provides smooth estimates of changes in social mobility that have a clear interpretation and it can easily incorporate control variables and multiple dimensions of parental characteristics. To evaluate the validity of our approach, we employ the oft-used log-multiplicative layer effect model (Xie 1992) as a benchmark. Results indicate that our approach performs well and produces qualitatively similar findings as Xie’s model. For men, effects of social origin have been stable over the observed period. For women, however, social mobility significantly decreased among younger cohorts, mostly due to expanding female education and labor force participation. Jann, Ben, Benita Combet (2012). Zur Entwicklung der intergenerationalen Mobilität in der Schweiz (On the Development of Intergenerational Mobility in Switzerland). Swiss Journal of Sociology 38(2): 177-199. Xie, Yu (1992). The Log-Multiplicative Layer Effect Model for Comparing Mobility Tables. American Sociological Review 57(3): 380-395.

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Rice has the predilection to take up arsenic in the form of methylated arsenic (o-As) and inorganic arsenic species (i-As). Plants defend themselves using i-As efflux systems and the production of phytochelatins (PCs) to complex i-As. Our study focused on the identification and quantification of phytochelatins by HPLC-ICP-MS/ESI-MS, relating them to the several variables linked to As exposure. GSH, 11 PCs, and As–PC complexes from the roots of six rice cultivars (Italica Carolina, Dom Sofid, 9524, Kitrana 508, YRL-1, and Lemont) exposed to low and high levels of i-As were compared with total, i-As, and o-As in roots, shoots, and grains. Only Dom Sofid, Kitrana 508, and 9524 were found to produce higher levels of PCs even when exposed to low levels of As. PCs were only correlated to i-As in the roots (r=0.884, P <0.001). However, significant negative correlations to As transfer factors (TF) roots–grains (r= –0.739, P <0.05) and shoots–grains (r= –0.541, P <0.05), suggested that these peptides help in trapping i-As but not o-As in the roots, reducing grains’ i-As. Italica Carolina reduced i-As in grains after high exposure, where some specific PCs had a special role in this reduction. In Lemont, exposure to elevated levels of i-As did not result in higher i-As levels in the grains and there were no significant increases in PCs or thiols. Finally, the high production of PCs in Kitrana 508 and Dom Sofid in response to high As treatment did not relate to a reduction of i-As in grains, suggesting that other mechanisms such as As–PC release and transport seems to be important in determining grain As in these cultivars.

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Tibetan pastoralist communities in Amdo, the north-eastern region of the Tibetan plateau, have undergone tremendous change due to a number of state induced modernisation processes. Road infrastructure is but one development that aims to facilitate transition from subsistence to a market economy and to link remote pastoralist production into the global or regional market. This paper starts from the local perspective and examines how the expansion of road infrastructure and increased ownership of motorised vehicles has impacted on the mobility of pastoralists. It argues that motorisation and the increased availability of roads creates an interface for pastoralists through which they negotiate a newly emerging translocality. Roads are embedded into everyday movements and provide pastoralists with ways to integrate new developments into their lives.

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New Zealand English first emerged at the beginning of the 19th century as a result of the dialect contact of British (51%), Scottish (27.3%) and Irish (22%) migrants (Hay and Gordon 2008:6). This variety has subsequently developed into an autonomous and legitimised national variety and enjoys a distinct socio-political status, recognition and codification. In fact, a number of dictionaries of New Zealand English have been published1 and the variety is routinely used as the official medium on TV, radio and other media. This however, has not always been the case, as for long only British standard norms were deemed suitable for media broadcasting. While there is some work already on lay commentary about New Zealand English (see for example Gordon 1983, 1994; Hundt 1998), there is much more to be done especially concerning more recent periods of the history of this variety and the ideologies underlying its development and legitimisation. Consequently, the current project aims at investigating the metalinguistic discourses during the period of transition from a British norm to a New Zealand norm in the media context, this will be done by focusing on debates about language in light of the advent of radio and television. The main purpose of this investigation is thus to examine the (language) ideologies that have shaped and underlain these discourses (e.g. discussions about the appropriateness of New Zealand English vis à vis external, British models of language) and their related practices in these media (e.g. broadcasting norms). The sociolinguistic and pragmatic effects of these ideologies will also be taken into account. Furthermore, a comparison will be carried out, at a later stage in the project, between New Zealand English and a more problematic and less legitimised variety: Estuary English. Despite plenty of evidence of media and other public discourses on Estuary English, in fact, there has been very little metalinguistic analysis of this evidence, nor examinations of the underlying ideologies in these discourses. The comparison will seek to discover whether similar themes emerge in the ideologies played out in publish discourses about these varieties, themes which serve to legitimise one variety, whilst denying such legitimacy to the other.

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Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides’ transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloro- ethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxico- logical risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change.

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Long Term Evolution (LTE) represents the fourth generation (4G) technology which is capable of providing high data rates as well as support of high speed mobility. The EU FP7 Mobile Cloud Networking (MCN) project integrates the use of cloud computing concepts in LTE mobile networks in order to increase LTE's performance. In this way a shared distributed virtualized LTE mobile network is built that can optimize the utilization of virtualized computing, storage and network resources and minimize communication delays. Two important features that can be used in such a virtualized system to improve its performance are the user mobility and bandwidth prediction. This paper introduces the architecture and challenges that are associated with user mobility and bandwidth prediction approaches in virtualized LTE systems.

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Based on fieldwork conducted between 2008 and 2011, this article explores the role of roads in enabling and limiting the movement of people and goods in Tajikistan’s Eastern Pamirs. The article focuses on the Pamir Highway and a newly established trade route linking Tajikistan with China. Besides materially facilitating mobility, both roads serve as trajectories for opportunities, but often also signify the lack of such to those who live along them. This article thus seeks to analyse the shifting roles of roads against the backdrop of past and present state dispensations, shifting ideologies and newly emerging economic practices. By emphasising roads as both enabling and limiting spatial entities shaped by materiality, politics and economics, this article argues, on the one hand, that roads are important factors in directing and accelerating the mobility of people and goods and, on the other, that roads are also symbols of immobility inasmuch as they set limitations on the movement of people.

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Excavations of Neolithic (4000 – 3500 BC) and Late Bronze Age (1200 – 800 BC) wetland sites on the northern Alpine periphery have produced astonishing and detailed information about the life and human environment of prehistoric societies. It is even possible to reconstruct settlement histories and settlement dynamics, which suggest a high degree of mobility during the Neolithic. Archaeological finds—such as pottery—show local typological developments in addition to foreign influences. Furthermore, exogenous lithic forms indicate far reaching interaction. Many hundreds of bronze artefacts are recorded from the Late Bronze Age settlements, demonstrating that some wetland sites were centres of bronzework production. Exogenous forms of bronzework are relatively rare in the wetland settlements during the Late Bronze Age. However, the products produced in the lake-settlements can be found widely across central Europe, indicating their continued involvement in interregional exchange partnerships. Potential motivations and dynamics of the relationships between sites and other regions of Europe will be detailed using case studies focussing on the settlements Seedorf Lobsigensee (BE), Concise (VD), and Sutz-Lattrigen Hauptstation innen (BE), and an initial assessment of intra-site connectivity through Network Analysis of sites within the region of Lake Neuchâtel, Lake Biel, and Lake Murten.