1,345 research outputs found
Renewing NASA: The Artemis Case for Celestial Competition, with Revisions
The role and scope of the National Aeronautics and Space Administration (NASA) has fluctuated throughout a number of mission-based cycles since the heightened publicity of the Apollo era. But throughout this history, NASAâs joint roles as the United Statesâ civilian research bastion on spaceflight and innovative public relations mission for American science leadership has remained unchanged. Surrounding this culture in the modern era is a new and continually-emerging commercial space sector, one which has made for the increased efficient use of often-waning federal dollars while enabling a swift timeline of revolutionary space travel. Enter the Artemis missions, originally developed as a NASA program to give use to the Space Launch System (SLS) rocketâthe most powerful rocket ever builtâand planned with the effort to return Americaâs next man and first woman to the moon as a next-step program for travel to deep space. While the original goal for this human lunar landing was 2028, the Trump administration in 2019 announced a call to accelerate this timeline to a 2024 landing, releasing the updated strategy (the âArtemis Planâ), however uncertain, a year later. This memorandum outlines the importance of NASA and its space-bound missions to both our national economy and global image and proposes a revised Artemis timeline (returning to the moon in 2028) that seeks to minimize the likelihood of a very public failure in the unmet 2024 goalâwhile understanding the careful political opportunities presented by what may be the final âgiant leapâ aboard a NASA-made rocket
Why does the Engel method work? Food demand, economies of size and household survey methods
Estimates of household size economies are needed for the analysis of poverty and inequality. This paper shows that Engel estimates of size economies are large when household expenditures are obtained by respondent recall but small when expenditures are obtained by daily recording in diaries. Expenditure estimates from recall surveys appear to have measurement errors correlated with household size. As well as demonstrating the fragility of Engel estimates of size economies, these results help resolve a puzzle raised by Deaton and Paxson (1998) about differences between rich and poor countries in the effect of household size on food demand
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H3K27 modifications define segmental regulatory domains in the Drosophila bithorax complex
The bithorax complex (BX-C) in Drosophila melanogaster is a cluster of homeotic genes that determine body segment identity. Expression of these genes is governed by cis-regulatory domains, one for each parasegment. Stable repression of these domains depends on Polycomb Group (PcG) functions, which include trimethylation of lysine 27 of histone H3 (H3K27me3). To search for parasegment-specific signatures that reflect PcG function, chromatin from single parasegments was isolated and profiled. The H3K27me3 profiles across the BX-C in successive parasegments showed a âstairstepâ pattern that revealed sharp boundaries of the BX-C regulatory domains. Acetylated H3K27 was broadly enriched across active domains, in a pattern complementary to H3K27me3. The CCCTC-binding protein (CTCF) bound the borders between H3K27 modification domains; it was retained even in parasegments where adjacent domains lack H3K27me3. These findings provide a molecular definition of the homeotic domains, and implicate precisely positioned H3K27 modifications as a central determinant of segment identity. DOI: http://dx.doi.org/10.7554/eLife.02833.00
Randomized Control Trials and Qualitative Evaluations of a Multifaceted Programme for Women in Extreme Poverty: Empirical Findings and Methodological Reflections
This paper sets out to synthesize key lessons from studies using alternative methodologies to impact assessment. Drawing on Senâs capability approach as a conceptual framework, it analyses two pairs of impact assessments which were carried out in West Bengal and Sindh around the same time and within close proximity to each other. Each pair consisted of a randomized control trial and a qualitative assessment of attempts to pilot BRACâs approach to transferring assets to women in extreme poverty. The paper reports on the findings of these studies, their strategies for establishing their claims about causality and the information base they drew on to establish these claims. It finds that not only did the RCTs fail to meet their own criteria for establishing causality, but they also provided very limited explanation for the patterns of outcomes observed. Such information formed the substance of the qualitative studies. The paper concludes that greater use of mixed methods could help to offset some of limitations of RCTs and to place their findings on much firmer ground
Consumer price indexes: an analysis of heterogeneity across sub-populations
La rilevanza dell'Indece dei Prezzi al Consumo quale misura dell'inflazione è stata a lungo dibattuta in particolare esminando le differenti cause di distorsione dovute all'utilizzo di un paniere fisso di beni e servizi. Di conseguenza la letteratura ha proposto indici dei prezzi sperimentali per particolari sottogruppi di popolazioni. tali indici hanno rilevanza ai fini della politica economica e sociale, poichÊ è probabile che differenti gruppi di popolazione abbiano comportamenti nei consumi differenti dalla media, ad esempio i consumatori poveri (Garner, Johnson & Kokoski, 1996) e quelli anziani (Stewart, 2008). Lo scopo di questo lavoro è quello di esaminare le possibilità offerte da metodi di costruzione alternativi degli Indici dei Prezzi al Consumo ai fini di cogliere la variabilità dei tassi di inflazione relativi a differenti categorie di consumatori.The soundeness of Consumer Price Indexes (CPI) as a measure of inflation has long been debeate, focusing on the different sources of bias inherent to use of a constant basket of goods and services. Thus experimental consumer price indexes have been proposed for targeted sub-populations specifically relevant for social and economic policy, that are likely to have consumption patterns different from yhe average, i.e poor (Garner, Johnson & Kokoski, 1996) and elderly (Stewart, 2008)houseolds. Aim of this work is to investigate the possibilities offered by alternative methods of construction of consumer price indices in order to capture the variability of inflation rates facing different houseolds' types
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Poverty reduction during 1990-2013: did millennium development goals adoption and state capacity matter?
While poverty reduction remains central in the Post-2015 Agenda, its determinants remain debated in the literature, especially the role of structural conditions related to governance. This paper provides an assessment of two key dimensions: the global adoption of MDGs and state capacity. We do so by studying whether they facilitated convergence in income poverty measures, using cross-section and panel methods, with data on 89 developing economies for the period 1990â2013. We find that poverty headcount and gap measures tended to decrease faster in countries with initially higher income poverty. Such convergence accelerated after 2000, suggesting that MDGs adoption was instrumental to poverty reduction. However, this still leaves unexplained substantial variation in poverty reduction performance across countries. Such variation is explained by state capacity: countries with greater ability to administer their territories in 1990 experienced faster income poverty reduction and were more likely to have achieved the MDG target. This result is insensitive to robust regression methods and to a large set of controls (initial level of income, dependence on natural resources, education and health inputs, dependence on foreign aid, ethnic fractionalization, regional effects and a set of governance variables). As good governance and effective institutions are included in the Sustainable Development Goals, this result provides empirical justification for this move, suggesting that more effective states could be crucial to sustain the development progress achieved so far
Immune sensitization of equine bronchus: glutathione, IL-1β expression and tissue responsiveness
BACKGROUND: Increasing clinical epidemiological and experimental evidence indicates that excess of production of reactive oxygen free radicals (ROS) induced by an oxidative stress is involved in the pathogenesis of a number of human airway disorders, as well as equine recurrent airway obstruction. Free-radicals modulate the activation of transcription factors, such as nuclear factor-(NF)-ÎşB and activator protein (AP)-1, in several different cells. This activation leads to expression of many pro-inflammatory cytokines, including interleukin (IL)-1β. We have hypothesized that equine airway sensitization might induce an oxidative stress and increase the ROS production, which in turn might enhance a production of IL-1β and airway hyperresponsiveness. METHODS: We have examined the effect of passive sensitization on IL-1β mRNA expression and electrical field stimulation (EFS)-induced contraction in equine isolated bronchi, and the potential interference of reduced-glutathione (GSH), an antioxidant, with these responses. Bronchi passively sensitized with serum from animals suffering from heaves and having high total level of IgE, and control tissues, either pretreated or not with GSH (100 ÎźM), were used to quantify IL-1β mRNA. Other tissues were used to study the effect of EFS (3â10â25 Hz). RESULTS: Mean IL-1β mRNA expression was higher in passively sensitized than in control rings. GSH significantly (p < 0.05) reduced the IL-1β mRNA expression only in passively sensitized bronchi. ELF induced a frequency-dependent contraction in both non-sensitized and passively sensitized tissues, with a significantly greater response always observed in sensitized tissues. GSH did not modify the EFS-induced contraction in non-sensitized bronchi, but significantly (p < 0.05) decreased it in passively sensitized tissues. CONCLUSION: Our data indicate that the passive sensitization of equine bronchi induces inflammation and hyperresponsiveness. These effects might be due to an oxidative stress because a pretreatment with GSH decreased the increased IL-1β mRNA expression and responsiveness to EFS of passively sensitized bronchi
ECOPHAGE: Combating Antimicrobial Resistance Using Bacteriophages for Eco-Sustainable Agriculture and Food Systems
The focus of this meeting was to discuss the suitability of using bacteriophages as alternative antimicrobials in the agrifood sector. Following a One Health approach, the workshop explored the possibilities of implementing phage application strategies in the agriculture, animal husbandry, aquaculture, and food production sectors. Therefore, the meeting had gathered phage researchers, representatives of the agrifood industry, and policymakers to debate the advantages and potential shortcomings of using bacteriophages as alternatives to traditional antimicrobials and chemical pesticides. Industry delegates showed the latest objectives and demands from consumers. Representatives of regulatory agencies (European Medicines Agency (EMA) and Spanish Agency of Medicines and Health Products (AEMPS)) presented an update of new regulatory aspects that will impact and support the approval and implementation of phage application strategies across the different sectors
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