58 research outputs found
Livelihood Shocks and Coping Strategies: An Empirical Study of Bangladesh Households
Households plan strategically for facing risks associated with livelihood security. Choosing a particular set of coping strategies depends on a number of factors including the types of crisis households face and options available. Often, poor households risk future income generating capacity for maintaining current food consumption. This paper examines strategies used by rural households for coping with the shocks and investigates whether there is any distinctive pattern in adopting these strategies. Using a cross section data set covering 1600 households from the northwestern Bangladesh, we estimate a trivariate probit model for explaining the adoption of coping strategies. Results indicate that choice of coping strategies depend on diversity and stability of household income sources. Households with higher education have greater access to stable incomes sources and have more income sources, and so are less likely to adopt ex-post coping strategies. Households with more assets are more likely to divest assets or obtain secured loans rather than rely on unsecured loans. Wealthier households are not less likely to adopt current adjustment strategies, suggesting that there is a general sequence of coping strategies that all households follow, irrespective of the assets they own.Consumer/Household Economics,
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Food system resilience measurement: principles, framework and caveats
There is growing recognition that a better understanding of how food systems respond to crises is critical to build and protect the food security of local populations. But rigorous and reliable methods to measure food system resilience are still missing. In this paper, we build on the current literature to develop an analytical framework aimed at assessing the resilience of food systems at local level. The novel element of the analysis lies in the levels at which resilience is considered. Combining the individual actor level with the notion of 'emergent properties' of food systems, we argue that the overall resilience of food system results from processes that take place – and need to be measured – at both individual and system levels. The framework is structured around three components: (i) the mapping of the actors and the local food system; (ii) the assessment of the resilience of these actors and that of the food system, and (iii) the outcomes of this resilience, assessed in term of local population’s food security. For each of those components, indicators are proposed and the ways to collect them are discussed. The paper then presents the types of analyses that would be necessary to complete to gain a better understanding of the situation regarding the resilience of the local food system under consideration, including the analysis of “positive deviance” among food system actors. The paper concludes with a series of reflections about the caveats and challenges that one may face when attempting to assess food system resilience
‘Perception matters’: New insights into the subjective dimension of resilience in the context of humanitarian and food security crises
In the emerging literature on resilience in relation to food security, a growing number of studies stress the need to expand our analysis beyond conventional socio-economic factors such as assets or social capital, and to consider less tangible elements such as risk perception, self-efficacy or aspiration. Drawing on the recent literature and the authors’ own experience, a conceptual framework of subjective resilience is proposed. The framework helps locating the subjective element of resilience within the wider resilience conceptualization as currently developed in the literature on food security and to clarify how it links to the more tangible elements of that conceptualization. Empirical data are then used to test the framework. The analysis demonstrates the relevance of the concept of subjective resilience and the central role that psychosocial factors and individual perceptions play in people’s construct of resilience in the context of humanitarian and food security crises. The article concludes with a discussion of the implications of those findings
Onchocerca parasites and Wolbachia endosymbionts: evaluation of a spectrum of antibiotic types for activity against Onchocerca gutturosa in vitro
BACKGROUND: The filarial parasites of major importance in humans contain the symbiotic bacterium Wolbachia and recent studies have shown that targeting of these bacteria with antibiotics results in a reduction in worm viability, development, embryogenesis, and survival. Doxycycline has been effective in human trials, but there is a need to develop drugs that can be given for shorter periods and to pregnant women and children. The World Health Organisation-approved assay to screen for anti-filarial activity in vitro uses male Onchocerca gutturosa, with effects being determined by worm motility and viability as measured by reduction of MTT to MTT formazan. Here we have used this system to screen antibiotics for anti-filarial activity. In addition we have determined the contribution of Wolbachia depletion to the MTT reduction assay. METHODS: Adult male O. gutturosa were cultured on a monkey kidney cell (LLCMK 2) feeder layer in 24-well plates with antibiotics and antibiotic combinations (6 to 10 worms per group). The macrofilaricide CGP 6140 (Amocarzine) was used as a positive control. Worm viability was assessed by two methods, (i) motility levels and (ii) MTT/formazan colorimetry. Worm motility was scored on a scale of 0 (immotile) to 10 (maximum) every 5 days up to 40 days. On day 40 worm viability was evaluated by MTT/formazan colorimetry, and results were expressed as a mean percentage reduction compared with untreated control values at day 40. To determine the contribution of Wolbachia to the MTT assay, the MTT formazan formation of an insect cell-line (C6/36) with or without insect Wolbachia infection and treated or untreated with tetracycline was compared. RESULTS: Antibiotics with known anti-Wolbachia activity were efficacious in this system. Rifampicin (5 × 10(-5)M) was the most effective anti-mycobacterial agent; clofazimine (1.25 × 10(-5)M and 3.13 × 10(-6)M) produced a gradual reduction in motility and by 40 days had reduced worm viability. The other anti-mycobacterial drugs tested had limited or no activity. Doxycycline (5 × 10(-5)M) was filaricidal, but minocycline was more effective and at a lower concentration (5 × 10(-5)M and 1.25 × 10(-5)M). Inactive compounds included erythromycin, oxytetracycline, trimethoprim and sulphamethoxazole. The MTT assay on the insect cell-line showed that Wolbachia made a significant contribution to the metabolic activity within the cells, which could be reduced when they were exposed to tetracycline. CONCLUSION: The O. gutturosa adult male screen for anti-filarial drug activity is also valid for the screening of antibiotics for anti-Wolbachia activity. In agreement with previous findings, rifampicin and doxycycline were effective; however, the most active antibiotic was minocycline. Wolbachia contributed to the formation of MTT formazan in the MTT assay of viability and is therefore not exclusively a measure of worm viability and indicates that Wolbachia contributes directly to the metabolic activity of the nematode
Prefrontal cortex output circuits guide reward seeking through divergent cue encoding
The prefrontal cortex is a critical neuroanatomical hub for controlling motivated behaviours across mammalian species. In addition to intra-cortical connectivity, prefrontal projection neurons innervate subcortical structures that contribute to reward-seeking behaviours, such as the ventral striatum and midline thalamus. While connectivity among these structures contributes to appetitive behaviours, how projection-specific prefrontal neurons encode reward-relevant information to guide reward seeking is unknown. Here we use in vivo two-photon calcium imaging to monitor the activity of dorsomedial prefrontal neurons in mice during an appetitive Pavlovian conditioning task. At the population level, these neurons display diverse activity patterns during the presentation of reward-predictive cues. However, recordings from prefrontal neurons with resolved projection targets reveal that individual corticostriatal neurons show response tuning to reward-predictive cues, such that excitatory cue responses are amplified across learning. By contrast, corticothalamic neurons gradually develop new, primarily inhibitory responses to reward-predictive cues across learning. Furthermore, bidirectional optogenetic manipulation of these neurons reveals that stimulation of corticostriatal neurons promotes conditioned reward-seeking behaviour after learning, while activity in corticothalamic neurons suppresses both the acquisition and expression of conditioned reward seeking. These data show how prefrontal circuitry can dynamically control reward-seeking behaviour through the opposing activities of projection-specific cell populations
A Tunguska Sized Airburst Destroyed Tall el‑Hammam a Middle Bronze Age City in the Jordan Valley Near the Dead Sea
We present evidence that in ~ 1650 BCE (~ 3600 years ago), a cosmic airburst destroyed Tall el-Hammam, a Middle-Bronze-Age city in the southern Jordan Valley northeast of the Dead Sea. The proposed airburst was larger than the 1908 explosion over Tunguska, Russia, where a ~ 50-m-wide bolide detonated with ~ 1000× more energy than the Hiroshima atomic bomb. A city-wide ~ 1.5-m-thick carbon-and-ash-rich destruction layer contains peak concentrations of shocked quartz (~ 5–10 GPa); melted pottery and mudbricks; diamond-like carbon; soot; Fe- and Si-rich spherules; CaCO(3) spherules from melted plaster; and melted platinum, iridium, nickel, gold, silver, zircon, chromite, and quartz. Heating experiments indicate temperatures exceeded 2000 °C. Amid city-side devastation, the airburst demolished 12+ m of the 4-to-5-story palace complex and the massive 4-m-thick mudbrick rampart, while causing extreme disarticulation and skeletal fragmentation in nearby humans. An airburst-related influx of salt (~ 4 wt.%) produced hypersalinity, inhibited agriculture, and caused a ~ 300–600-year-long abandonment of ~ 120 regional settlements within a > 25-km radius. Tall el-Hammam may be the second oldest city/town destroyed by a cosmic airburst/impact, after Abu Hureyra, Syria, and possibly the earliest site with an oral tradition that was written down (Genesis). Tunguska-scale airbursts can devastate entire cities/regions and thus, pose a severe modern-day hazard
Measuring food insecurity: Can an indicator based on localized coping behaviors be used to compare across contexts?
The Coping Strategies Index (CSI) was developed as a context-specific indicator of food insecurity that counts up and weights coping behaviors at the household level. It has proven useful to operational humanitarian agencies and researchers in measuring localized food insecurity, but to date has not been useful to compare the relative severity of different crises and has therefore has not been particularly useful for geographic targeting or resource allocation. This paper analyzes data from 14 surveys in crisis-affected or chronically vulnerable countries in Sub-Saharan Africa that incorporated the context-specific CSI. The paper identifies a sub-set of individual coping behaviors common to all surveys, whose severity is regarded as broadly similar by households across these studies. Data from these studies were re-analyzed using a reduced index constructed from only these behaviors. Correlations of this new index with other known food security indicators are similar to those of the complete, context-specific CSI. This suggests the possibility that an indicator based on these common behaviors could be used to compare the types of food security crises analyzed here across different contexts - particularly in Sub-Saharan Africa - to improve geographic targeting and resource allocation, according to the severity of crises. This new, more comparative indicator can be generated with no loss to the context-specific nature of the original CSI, which has proven useful for assessment and monitoring purposes.Food security Sub-Saharan Africa Coping strategies Indicator Comparability Humanitarian emergency
Livelihood Shocks and Coping Strategies: An Empirical Study of Bangladesh Households
Households plan strategically for facing risks associated with livelihood security. Choosing a particular set of coping strategies depends on a number of factors including the types of crisis households face and options available. Often, poor households risk future income generating capacity for maintaining current food consumption. This paper examines strategies used by rural households for coping with the shocks and investigates whether there is any distinctive pattern in adopting these strategies. Using a cross section data set covering 1600 households from the northwestern Bangladesh, we estimate a trivariate probit model for explaining the adoption of coping strategies. Results indicate that choice of coping strategies depend on diversity and stability of household income sources. Households with higher education have greater access to stable incomes sources and have more income sources, and so are less likely to adopt ex-post coping strategies. Households with more assets are more likely to divest assets or obtain secured loans rather than rely on unsecured loans. Wealthier households are not less likely to adopt current adjustment strategies, suggesting that there is a general sequence of coping strategies that all households follow, irrespective of the assets they own
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