356 research outputs found

    Living with Conflict: The Effect of Community Organizations, Economic Assets, and Mass Media Consumption on Migration During Armed Conflict.

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    This dissertation is an examination of migration during armed conflict and the individual and community characteristics that shape this relationship. Although evidence consistently shows that conflict affects migration on an aggregate level, there is little theoretical or empirical work at the micro-level that addresses the individual- and community-level determinants that make people willing and able to migrate during conflict. To address this gap, I develop multi-dimensional theoretical models that analyze migration decisions at the individual level and the role of community organizations, employment and economic status, and consumption of mass media in systematically altering the way individuals react to armed conflict. Using the recent Maoist insurrection in Nepal as a case study, I empirically test these theoretical models with prospective survey data and detailed records of specific violent events. I find that specific violent events have different effects on migration, with gun battles increasing and bomb blasts decreasing the likelihood of migration. Within this context, community organizations can provide economic and social support that mitigates the influence of conflict on individuals’ lives. I find evidence that organizations such as markets, employers, farmers’ cooperatives, and religious institutions dampened the effect of violent events on migration. Economic indicators also moderated the conflict-migration relationship. Location specific characteristics that an individual could lose upon migration, such as employment and land ownership, decreased migration after any violent event. Conversely livestock, which are a more liquid asset, increased migration after violent events. Finally, results show that use of the mass media positively affected migration during the conflict, likely through the provision of information and influencing exaggerated perceptions of threat. Overall, this dissertation contributes to the academic literature through the construction and empirical testing of theoretical models of individual migration decisions during armed conflict. I demonstrate that individuals react to violence differently, depending upon their individual and community circumstances which affect their experience and perceptions of violence and the utility and ability to migrate away. I also demonstrate that detailed measurement of the specific events that constitute armed conflict is necessary to effectively study subsequent behaviors.Ph.D.SociologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64592/1/natw_1.pd

    Collecting Survey Data during Armed Conflict

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    Surveys provide crucial information about the social consequences of armed conflict, but armed conflict can shape surveys in ways that limit their value. We use longitudinal survey data from throughout the recent armed conflict in Nepal to investigate the relationship between armed conflict events and survey response. The Chitwan Valley Family Study (CVFS) provides a rare window into survey data collection through intense armed conflict. The CVFS data reveal that with operational strategies tailored to the specific conflict, duration of the panel study is the main determinant of attrition from the study, just as in most longitudinal studies outside of conflict settings. Though minor relative to duration, different dimensions of armed conflict can affect survey response in opposing directions, with bombings in the local area reducing response rates but nationwide political events increasing response rates. This important finding demonstrates that survey data quality may be affected differently by various dimensions of armed conflict. Overall, CVFS response rates remained exceptionally high throughout the conflict. We use the CVFS experience to identify principles likely to produce higher quality surveys during periods of generalized violence and instability

    Towards a macroscope : leveraging technology to transform the breadth, scale and resolution of macroecological data

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    M.D. is grateful for support from the Templeton Foundation (grant #60501, “Putting the Extended Evolutionary Synthesis to the Test”) and from a Leverhulme Trust Fellowship.The problem Earth‐based observations of the biosphere are spatially biased in ways that can limit our ability to detect macroecological patterns and changes in biodiversity. To resolve this problem, we need to supplement the ad hoc data currently collected with planned biodiversity monitoring, in order to approximate global stratified random sampling of the planet. We call this all‐encompassing observational system ‘the macroscope’. The solution With a focus on the marine realm, we identify seven main biosphere observation tools that compose the macroscope: satellites, drones, camera traps, passive acoustic samplers, biologgers, environmental DNA and human observations. By deploying a nested array of these tools that fills current gaps in monitoring, we can achieve a macroscope fit for purpose and turn these existing powerful tools into more than the sum of their parts. An appeal Building a macroscope requires commitment from many fields, together with coordinated actions to attract the level of funding required for such a venture. We call on macroecologists to become advocates for the macroscope and to engage with existing global observation networks.PostprintPeer reviewe

    A Micro-Level Event-Centered Approach to Investigating Armed Conflict and Population Responses

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    In this article, we construct and test a micro-level event-centered approach to the study of armed conflict and behavioral responses in the general population. Event-centered approaches have been successfully used in the macro-political study of armed conflict but have not yet been adopted in micro-behavioral studies. The micro-level event-centered approach that we advocate here includes decomposition of a conflict into discrete political and violent events, examination of the mechanisms through which they affect behavior, and consideration of differential risks within the population. We focus on two mechanisms: instability and threat of harm. We test this approach empirically in the context of the recent decade-long armed conflict in Nepal, using detailed measurements of conflict-related events and a longitudinal study of first migration, first marriage, and first contraceptive use. Results demonstrate that different conflict-related events independently shaped migration, marriage, and childbearing and that they can simultaneously influence behaviors in opposing directions. We find that violent events increased migration, but political events slowed migration. Both violent and political events increased marriage and contraceptive use net of migration. Overall, this micro-level event-centered approach yields a significant advance for the study of how armed conflict affects civilian behavioral responses

    Climate shocks and migration: an agent-based modeling approach

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    This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative and quantitative analyses of a well-studied demographic field site, Nang Rong district, Northeast Thailand. With this model, we simulate patterns of migration under four weather regimes in a rice economy: 1) a reference, ‘normal’ scenario; 2) seven years of unusually wet weather; 3) seven years of unusually dry weather; and 4) seven years of extremely variable weather. Results show relatively small impacts on migration. Experiments with the model show that existing high migration rates and strong selection factors, which are unaffected by climate change, are likely responsible for the weak migration response

    “I h 8 u”: Findings from a five-year study of text and e-mail bullying

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    Copyright @ 2010 British Educational Research Association. The final version of this article is available at the link below.This study charts reports of nasty or threatening text and e-mail messages received by students in academic years 7 and 8 (11-13 years of age) attending 13 secondary schools in the North of England between 2002-2006. Annual surveys were undertaken on behalf of the local education authority (LEA) to monitor bullying. Results indicated that, over five years, the number of pupils receiving one or more nasty or threatening text messages or e-mails increased significantly, particularly among girls. However, receipt of frequent nasty or threatening text and e-mail messages remained relatively stable. For boys, being a victim of direct-physical bullying was associated with receiving nasty or threatening text and e-mail messages; for girls it was being unpopular among peers. Boys received more hate-related messages and girls were primarily the victims of name-calling, Findings are discussed with respect to theoretical and policy developments, and recommendations for future research are offered

    Epitope Density Influences CD8+ Memory T Cell Differentiation

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    The generation of long-lived memory T cells is critical for successful vaccination but the factors controlling their differentiation are still poorly defined. We tested the hypothesis that the strength of T cell receptor (TCR) signaling contributed to memory CD8(+) T cell generation.We manipulated the density of antigenic epitope presented by dendritic cells to mouse naĂŻve CD8(+) T cells, without varying TCR affinity. Our results show that a two-fold decrease in antigen dose selectively affects memory CD8(+) T cell generation without influencing T cell expansion and acquisition of effector functions. Moreover, we show that low antigen dose alters the duration of the interaction between T cells and dendritic cells and finely tunes the expression level of the transcription factors Eomes and Bcl6. Furthermore, we demonstrate that priming with higher epitope density results in a 2-fold decrease in the expression of Neuron-derived orphan nuclear receptor 1 (Nor-1) and this correlates with a lower level of conversion of Bcl-2 into a pro-apoptotic molecule and an increased number of memory T cells.Our results show that the amount of antigen encountered by naĂŻve CD8(+) T cells following immunization with dendritic cells does not influence the generation of functional effector CD8(+) T cells but rather the number of CD8(+) memory T cells that persist in the host. Our data support a model where antigenic epitope density sensed by CD8(+) T cells at priming influences memory generation by modulating Bcl6, Eomes and Nor-1 expression

    Role of the Endogenous Antioxidant System in the Protection of Schistosoma mansoni Primary Sporocysts against Exogenous Oxidative Stress

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    Antioxidants produced by the parasite Schistosoma mansoni are believed to be involved in the maintenance of cellular redox balance, thus contributing to larval survival in their intermediate snail host, Biomphalaria glabrata. Here, we focused on specific antioxidant enzymes, including glutathione-S-transferases 26 and 28 (GST26 and 28), glutathione peroxidase (GPx), peroxiredoxin 1 and 2 (Prx1 and 2) and Cu/Zn superoxide dismutase (SOD), known to be involved in cellular redox reactions, in an attempt to evaluate their endogenous antioxidant function in the early-developing primary sporocyst stage of S. mansoni. Previously we demonstrated a specific and consistent RNA interference (RNAi)-mediated knockdown of GST26 and 28, Prx1 and 2, and GPx transcripts, and an unexpected elevation of SOD transcripts in sporocysts treated with gene-specific double-stranded (ds)RNA. In the present followup study, in vitro transforming sporocysts were exposed to dsRNAs for GST26 and 28, combined Prx1/2, GPx, SOD or green-fluorescent protein (GFP, control) for 7 days in culture, followed by assessment of the effects of specific dsRNA treatments on protein levels using semi-quantitative Western blot analysis (GST26, Prx1/2 only), and larval susceptibility to exogenous oxidative stress in in vitro killing assays. Significant decreases (80% and 50%) in immunoreactive GST26 and Prx1/2, respectively, were observed in sporocysts treated with specific dsRNA, compared to control larvae treated with GFP dsRNA. Sporocysts cultured with dsRNAs for GST26, GST28, Prx1/2 and GPx, but not SOD dsRNA, were significantly increased in their susceptibility to H2O2 oxidative stress (60–80% mortalities at 48 hr) compared to GFP dsRNA controls (∌18% mortality). H2O2-mediated killing was abrogated by bovine catalase, further supporting a protective role for endogenous sporocyst antioxidants. Finally, in vitro killing of S. mansoni sporocysts by hemocytes of susceptible NMRI B. glabrata snails was increased in larvae treated with Prx1/2, GST26 and GST28 dsRNA, compared to those treated with GFP or SOD dsRNAs. Results of these experiments strongly support the hypothesis that endogenous expression and regulation of larval antioxidant enzymes serve a direct role in protection against external oxidative stress, including immune-mediated cytotoxic reactions. Moreover, these findings illustrate the efficacy of a RNAi-type approach in investigating gene function in larval schistosomes
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