596 research outputs found

    Adaptation to divergent larval diets in the medfly, Ceratitis capitata

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    Variation in diet can influence the timing of major life history events and can drive population diversification and ultimately speciation. Proximate responses of life histories to diet have been well studied. However, there are scant experimental data on how organisms adapt to divergent diets over the longer term. We focused on this omission by testing the responses of a global pest, the Mediterranean fruitfly, to divergent selection on larval diets of different nutritional profiles. Tests conducted before and after 30 generations of nutritional selection revealed a complex interplay between the effects of novel larval dietary conditions on both plastic and evolved responses. There were proximate-only responses to the larval diet in adult male courtship and the frequency of copulation. Males on higher calorie larval diets consistently engaged in more bouts of energetic courtship. In contrast, following selection, larval development time and egg to adult survival showed evidence of evolved divergence between diet regimes. Adult body size showed evidence for adaptation, with flies being significantly heavier when reared on their ‘own’ diet. The results show the multifaceted responses of individuals to dietary selection and are important in understanding the extreme generalism exhibited by the medfly

    Understanding the political motivations that shape Rwanda’s emergent developmental state

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    Twenty years after its horrific genocide, Rwanda has become a model for economic development. At the same time, its government has been criticized for its authoritarian tactics and use of violence. Missing from the often-polarized debate are the connections between these two perspectives. Synthesizing existing literature on Rwanda in light of a combined year of fieldwork, we argue that the GoR is using the developmental infrastructure to deepen state power and expand political control. We first identify the historical pressures that have motivated the Rwanda Patriotic Front (RPF) to re-imagine the political landscape. Sectarian unrest, political rivalry, wider regional insecurity, and aid withdrawal have all pressured the RPF to identify growth as strategic. However, the country’s political transformation extends beyond a prioritisation of growth and encompasses the reordering of the social and physical layout of the territory, the articulation of new ideologies and mindsets, and the provision of social services and surveillance infrastructure. Growth and social control go hand in hand. As such, the paper’s main contribution is to bring together the two sides of the Rwandan debate and place the country in a broader sociological literature about the parallel development of capitalist relations and transformations in state power

    Subglacial topography and geothermal heat flux: potential interactions with drainage of the Greenland ice sheet

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    This is the published version, also available here: http://dx.doi.org/10.1029/2007GL030046.[1] Many of the outlet glaciers in Greenland overlie deep and narrow trenches cut into the bedrock. It is well known that pronounced topography intensifies the geothermal heat flux in deep valleys and attenuates this flux on mountains. Here we investigate the magnitude of this effect for two subglacial trenches in Greenland. Heat flux variations are estimated for idealized geometries using solutions for plane slopes derived by Lachenbruch (1968). It is found that for channels such as the one under Jakobshavn Isbræ, topographic effects may increase the local geothermal heat flux by as much as 100%

    Improving the Quality of Child Care in the Rural South

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    A collaborative of six social service agencies and a state university determined that the single most pressing need of families in a 14-county, rural area was child care. The Training Resource Center, developed through a W K. Kellogg Foundation grant, worked with day care licensing and early childhood professional groups to develop a plan to address the systemic nature of the problem of how to improve the quality of child care. Programs developed included training, mentoring, NAEYC accreditation, and a resource library. After 15 months, some programs show the possibility of sustainability

    Accentuating the positive and eliminating the negative: Efficacy of TiO2 as digestibility index marker for poultry nutrition studies

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    Inert digestibility index markers such as titanium dioxide are universally accepted to provide simple measurement of digestive tract retention and relative digestibility in poultry feeding trials. Their use underpins industry practice: specifically dosing regimens for adjunct enzymes added to animal feed. Among these, phytases, enzymes that degrade dietary phytate, inositol hexakisphosphate, represent a billion-dollar sector in an industry that raises ca. 70 billion chickens/annum. Unbeknown to the feed enzyme sector, is the growth in cell biology of use of titanium dioxide for enrichment of inositol phosphates from extracts of cells and tissues. The adoption of titanium dioxide in cell biology arises from its affinity under acid conditions for phosphates, suggesting that in feeding trial contexts that target phytate degradation this marker may not be as inert as assumed. We show that feed grade titanium dioxide enriches a mixed population of higher and lower inositol phosphates from acid solutions. Additionally, we compared the extractable inositol phosphates in gizzard and ileal digesta of 21day old male Ross 308 broilers fed three phytase doses (0, 500 and 6000 FTU/kg feed) and one inositol dose (2g/kg feed). This experiment was performed with or without titanium dioxide added as a digestibility index marker at a level of 0.5%, with all diets fed for 21 days. Analysis yielded no significant difference in effect of phytase inclusion in the presence or absence of titanium dioxide. Thus, despite the utility of titanium dioxide for recovery of inositol phosphates from biological samples, it seems that its use as an inert marker in digestibility trials is justified—as its inclusion in mash diets does not interfere with the recovery of inositol phosphates from digesta samples

    Phosphorus-specific, liquid chromatography inductively coupled plasma mass-spectrometry for analysis of inositol phosphate and inositol pyrophosphate metabolism

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    Inositol phosphate (InsP) and diphosphoinositol phosphate (PP-InsP) analysis in tissues is plagued by multiple difficulties of sensitivity, regioisomer resolution and the need for radiolabeling with metabolic precursors. We describe a liquid chromatography (LC) inductively coupled plasma (ICP) mass spectrometry (MS) method (LC-ICP-MS) that addresses all such issues and use LC-ICP-MS to analyse InsPs in avian tissues. The highly sensitive technique tolerates complex matrices and, by powerful chromatography, resolves in a single run multiple non-enantiomeric myo-inositol tetrakisphosphates, myo-inositol pentakisphosphates and all inositol hexakisphosphates, including myo-inositol 1,2,3,4,5,6-hexakisphosphate (phytate), known in nature. It also separates and quantifies diphospho myo-inositol pentakisphosphate (PP-InsP5) isomers from their biological precursors and from 1,5-bis-diphospho myo-inositol 2,3,4,6 tetrakisphosphate (1,5-[PP]2-InsP4). Gut tissue inositol phosphates, belonging to a non-canonical, lipid-independent pathway, are shown to differ from phytate digestion products and to be responsive to diet

    Clear purpose or sheer survival? National ministerial leadership across multiple arenas

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    Day-to-day political life for the most senior national politicians can be very pressurized and exposed. How they as individuals cope with constant challenges and make the most of opportunities for leadership is an under researched area. This is addressed in this interpretive study of the personal accounts of a small group of prominent U.K. politicians as they reflect, soon after leaving office, on their experiences as national ministers. The article connects generic leadership theory around practice and purpose with political leadership studies as a basis for a thematic analysis of ministers’ experiences across three key prominent arenas of ministerial life: relationships with the Prime Minister’s office, within their departments, and with their constituencies. Analysis of findings leads to a proposed analytical framework of active leadership in their everyday experience. The article concludes that active leadership practice is difficult but possible for leading national politicians

    Toward a Responsible Future: Recommendations for AI-Enabled Clinical Decision Support

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    BACKGROUND: Integrating artificial intelligence (AI) in healthcare settings has the potential to benefit clinical decision-making. Addressing challenges such as ensuring trustworthiness, mitigating bias, and maintaining safety is paramount. The lack of established methodologies for pre- and post-deployment evaluation of AI tools regarding crucial attributes such as transparency, performance monitoring, and adverse event reporting makes this situation challenging. OBJECTIVES: This paper aims to make practical suggestions for creating methods, rules, and guidelines to ensure that the development, testing, supervision, and use of AI in clinical decision support (CDS) systems are done well and safely for patients. MATERIALS AND METHODS: In May 2023, the Division of Clinical Informatics at Beth Israel Deaconess Medical Center and the American Medical Informatics Association co-sponsored a working group on AI in healthcare. In August 2023, there were 4 webinars on AI topics and a 2-day workshop in September 2023 for consensus-building. The event included over 200 industry stakeholders, including clinicians, software developers, academics, ethicists, attorneys, government policy experts, scientists, and patients. The goal was to identify challenges associated with the trusted use of AI-enabled CDS in medical practice. Key issues were identified, and solutions were proposed through qualitative analysis and a 4-month iterative consensus process. RESULTS: Our work culminated in several key recommendations: (1) building safe and trustworthy systems; (2) developing validation, verification, and certification processes for AI-CDS systems; (3) providing a means of safety monitoring and reporting at the national level; and (4) ensuring that appropriate documentation and end-user training are provided. DISCUSSION: AI-enabled Clinical Decision Support (AI-CDS) systems promise to revolutionize healthcare decision-making, necessitating a comprehensive framework for their development, implementation, and regulation that emphasizes trustworthiness, transparency, and safety. This framework encompasses various aspects including model training, explainability, validation, certification, monitoring, and continuous evaluation, while also addressing challenges such as data privacy, fairness, and the need for regulatory oversight to ensure responsible integration of AI into clinical workflow. CONCLUSIONS: Achieving responsible AI-CDS systems requires a collective effort from many healthcare stakeholders. This involves implementing robust safety, monitoring, and transparency measures while fostering innovation. Future steps include testing and piloting proposed trust mechanisms, such as safety reporting protocols, and establishing best practice guidelines
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