126 research outputs found

    Descartes on Physical Vacuum: Rationalism in Natural-Philosophical Debate

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    Descartes is notorious for holding a strong anti-vacuist position. On his view, according to the standard reading, empty space not only does not exist in nature, but it is logically impossible. The very notion of a void or vacuum is an incoherent one. Recently Eric Palmer has proposed a revisionist reading of Descartes on empty space, arguing that he is more sanguine about its possibility. Palmer makes use of Descartes’ early correspondence with Marin Mersenne, including his commentary on Galileo’s Two New Sciences. I argue that Palmer’s reading is mistaken, and that it relies on an understandable but faulty inference—i.e., that if Descartes considers the implications of an opposing view, he must find it at least coherent. Descartes, as I show from his correspondence and other texts, uses a variety of persuasive strategies, and levels charges of different logical strength, against positions which he takes to be incoherent. Thus we cannot infer from the fact that Descartes argues, e.g., that something is a superfluous theoretical entity, that he admits that entity’s coherence. He often chooses to argue a weaker thesis against an opponent so that he can use an argument to which the opponent is more likely to agree

    Survivor Experiences of Male Childhood Sexual Abuse: A Literature Review

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    The World Health Organization (WHO) recognizes childhood sexual abuse (CSA) as a global health issue. CSA is a human violation that affects both female and male children and has a stronger detrimental impact on mental health than other traumatic childhood experiences. Despite a growing awareness of male survivors of CSA, male survivors are a marginalized group as most CSA research focuses on females. In addition, masculine norms can keep male adults from disclosing further, which can delay support and increase mental health issues. This meta- analysis reviews the current literature on this group of marginalized people and concludes with a summary and future research directions on the complexities of male experience with a history of CSA and advocates for awareness of this marginalized population

    Plant genetic resources for agriculture, plant breeding, and biotechnology: Experiences from Cameroon, Kenya, the Philippines, and Venezuela

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    "Local farming communities throughout the world face binding productivity constraints, diverse nutritional needs, environmental concerns, and significant economic and financial pressures. Developing countries address these challenges in different ways, including public and private sector investments in plant breeding and other modern tools for genetic crop improvement. In order to measure the impact of any technology and prioritize investments, we must assess the relevant resources, human capacity, clusters, networks and linkages, as well as the institutions performing technological research and development, and the rate of farmer adoption. However, such measures have not been recently assessed, in part due to the lack of complete standardized information on public plant breeding and biotechnology research in developing countries. To tackle this void, the Food and Agricultural Organization of the United Nations (FAO), in consultation with the International Food Policy Institute (IFPRI) and other organizations, designed a plant breeding and biotechnology capacity survey for implementation by FAO consultants in 100 developing countries. IFPRI, in collaboration with FAO and national experts contracted by FAO to complete in-country surveys, identified and analyzed plant breeding and biotechnology programs in four developing countries: Cameroon, Kenya, the Philippines, and Venezuela. Here, we use an innovation systems framework to examine the investments in human and financial resources and the distribution of resources among the different programs, as well as the capacity and policy development for agricultural research in the four selected countries. Based on our findings, we present recommendations to help sustain and increase the efficiency of publicly- and privately-funded plant breeding programs, while maximizing the use of genetic resources and developing opportunities for GM crop production. Policy makers, private sector breeders, and other stakeholders can use this information to prioritize investments, consider product advancement, and assess the relative magnitude of the potential risks and benefits of their investments." from Author's Abstractplant breeding, biotechnology, public research, Funding, Innovation systems, Capacity building, Biosafety,

    Retinopathy of prematurity screening at ≥30 weeks: urinary NTpro-BNP performance

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    Aim: Urinary N-terminal B-type natriuretic peptide NTproBNP levels are associated with the development of retinopathy of prematurity (ROP) in infants <30 weeks of gestation. The incidence of ROP in more mature infants who meet other ROP screening criteria is very low. We therefore aimed to test whether urinary NTproBNP predicted ROP development in these infants. Methods: Prospective observational study in 151 UK infants ≥30 + 0 weeks of gestation but also <32 weeks of gestation and/or <1501 g, to test the hypothesis that urinary NTproBNP levels on day of life (DOL) 14 and 28 were able to predict ROP development. Results: Urinary NTproBNP concentrations on day 14 and day 28 of life did not differ between infants with and without ROP (medians 144 vs 128 mcg/mL, respectively, p = 0.86 on DOL 14 and medians 117 vs 94 mcg/mL, respectively, p = 0.64 on DOL28). Conclusion: The association previously shown for infants <30 completed weeks between urinary NTproBNP and the development of ROP was not seen in more mature infants. Urinary NTproBNP does not appear helpful in rationalising direct ophthalmoscopic screening for ROP in more mature infants, and may suggest a difference in pathophysiology of ROP in this population

    The R-Process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510

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    We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At [Fe/H]=-3.57, this is one of the lowest metallicity stars currently observed, with 18 measured abundances of neutron-capture elements. The presence of Ba, La, and Ce abundances above the Solar System r-process predictions suggest that there must have been a non-standard source of r-process elements operating at such low metallicities. One plausible explanation is that this enhancement originates from material ejected at unusually fast velocities in a neutron star merger event. We also explore the possibility that the neutron-capture elements were produced during the evolution and explosion of a rotating massive star. In addition, based on comparisons with yields from zero-metallicity faint supernova, we speculate that RAVE J1830-4555 was formed from a gas cloud pre-enriched by both progenitor types. From analysis based on Gaia DR2 measurements, we show that this star has orbital properties similar to the Galactic metal-weak thick-disk stellar population.Comment: Accepted for publication in Ap

    Reconstructing genome evolution in historic samples of the Irish potato famine pathogen

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    Responsible for the Irish potato famine of 1845–49, the oomycete pathogen Phytophthora infestans caused persistent, devastating outbreaks of potato late blight across Europe in the 19th century. Despite continued interest in the history and spread of the pathogen, the genome of the famine-era strain remains entirely unknown. Here we characterize temporal genomic changes in introduced P. infestans. We shotgun sequence five 19th-century European strains from archival herbarium samples—including the oldest known European specimen, collected in 1845 from the first reported source of introduction. We then compare their genomes to those of extant isolates. We report multiple distinct genotypes in historical Europe and a suite of infection-related genes different from modern strains. At virulence-related loci, several now-ubiquitous genotypes were absent from the historical gene pool. At least one of these genotypes encodes a virulent phenotype in modern strains, which helps explain the 20th century’s episodic replacements of European P. infestans lineages

    Visualization and 3D Reconstruction of Flame Cells of Taenia solium (Cestoda)

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    BACKGROUND: Flame cells are the terminal cells of protonephridial systems, which are part of the excretory systems of invertebrates. Although the knowledge of their biological role is incomplete, there is a consensus that these cells perform excretion/secretion activities. It has been suggested that the flame cells participate in the maintenance of the osmotic environment that the cestodes require to live inside their hosts. In live Platyhelminthes, by light microscopy, the cells appear beating their flames rapidly and, at the ultrastructural, the cells have a large body enclosing a tuft of cilia. Few studies have been performed to define the localization of the cytoskeletal proteins of these cells, and it is unclear how these proteins are involved in cell function. METHODOLOGY/PRINCIPAL FINDINGS: Parasites of two different developmental stages of T. solium were used: cysticerci recovered from naturally infected pigs and intestinal adults obtained from immunosuppressed and experimentally infected golden hamsters. Hamsters were fed viable cysticerci to recover adult parasites after one month of infection. In the present studies focusing on flame cells of cysticerci tissues was performed. Using several methods such as video, confocal and electron microscopy, in addition to computational analysis for reconstruction and modeling, we have provided a 3D visual rendition of the cytoskeletal architecture of Taenia solium flame cells. CONCLUSIONS/SIGNIFICANCE: We consider that visual representations of cells open a new way for understanding the role of these cells in the excretory systems of Platyhelminths. After reconstruction, the observation of high resolution 3D images allowed for virtual observation of the interior composition of cells. A combination of microscopic images, computational reconstructions and 3D modeling of cells appears to be useful for inferring the cellular dynamics of the flame cell cytoskeleton

    Redesigning crop varieties to win the race between climate change and food security

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    Climate change poses daunting challenges to agricultural production and food security. Rising temperatures, shifting weather patterns, and more frequent extreme events have already demonstrated their effects on local, regional, and global agricultural systems. Crop varieties that withstand climate-related stresses and are suitable for cultivation in innovative cropping systems will be crucial to maximize risk avoidance, productivity, and profitability under climate-changed environments. We surveyed 588 expert stakeholders to predict current and novel traits that may be essential for future pearl millet, sorghum, maize, groundnut, cowpea, and common bean varieties, particularly in sub-Saharan Africa. We then review the current progress and prospects for breeding three prioritized future-essential traits for each of these crops. Experts predict that most current breeding priorities will remain important, but that rates of genetic gain must increase to keep pace with climate challenges and consumer demands. Importantly, the predicted future-essential traits include innovative breeding targets that must also be prioritized; for example, (1) optimized rhizosphere microbiome, with benefits for P, N, and water use efficiency, (2) optimized performance across or in specific cropping systems, (3) lower nighttime respiration, (4) improved stover quality, and (5) increased early vigor. We further discuss cutting-edge tools and approaches to discover, validate, and incorporate novel genetic diversity from exotic germplasm into breeding populations with unprecedented precision, accuracy, and speed. We conclude that the greatest challenge to developing crop varieties to win the race between climate change and food security might be our innovativeness in defining and boldness to breed for the traits of tomorrow

    Plant trait and vegetation data along a 1314 m elevation gradient with fire history in Puna grasslands, Perú

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    Alpine grassland vegetation supports globally important biodiversity and ecosystems that are increasingly threatened by climate warming and other environmental changes. Trait-based approaches can support understanding of vegetation responses to global change drivers and consequences for ecosystem functioning. In six sites along a 1314 m elevational gradient in Puna grasslands in the Peruvian Andes, we collected datasets on vascular plant composition, plant functional traits, biomass, ecosystem fluxes, and climate data over three years. The data were collected in the wet and dry season and from plots with different fire histories. We selected traits associated with plant resource use, growth, and life history strategies (leaf area, leaf dry/wet mass, leaf thickness, specific leaf area, leaf dry matter content, leaf C, N, P content, C and N isotopes). The trait dataset contains 3,665 plant records from 145 taxa, 54,036 trait measurements (increasing the trait data coverage of the regional flora by 420%) covering 14 traits and 121 plant taxa (ca. 40% of which have no previous publicly available trait data) across 33 families
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