19 research outputs found

    From zero to infinity: Minimum to maximum diversity of the planet by spatio-parametric Rao's quadratic entropy

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    Aim: The majority of work done to gather information on the Earth's biodiversity has been carried out using in-situ data, with known issues related to epistemology (e.g., species determination and taxonomy), spatial uncertainty, logistics (time and costs), among others. An alternative way to gather information about spatial ecosystem variability is the use of satellite remote sensing. It works as a powerful tool for attaining rapid and standardized information. Several metrics used to calculate remotely sensed diversity of ecosystems are based on Shannon’s information theory, namely on the differences in relative abundance of pixel reflectances in a certain area. Additional metrics like the Rao’s quadratic entropy allow the use of spectral distance beside abundance, but they are point descriptors of diversity, that is they can account only for a part of the whole diversity continuum. The aim of this paper is thus to generalize the Rao’s quadratic entropy by proposing its parameterization for the first time.
 Innovation: The parametric Rao’s quadratic entropy, coded in R, (a) allows the representation of the whole continuum of potential diversity indices in one formula, and (b) starting from the Rao’s quadratic entropy, allows the explicit use of distances among pixel reflectance values, together with relative abundances.
 Main conclusions: The proposed unifying measure is an integration between abundance- and distance-based algorithms to map the continuum of diversity given a satellite image at any spatial scale. Being part of the rasterdiv R package, the proposed method is expected to ensure high robustness and reproducibility

    CHARACTERISTICS OF ORGANIZATIONAL READINESS FOR LARGE-SCALE HEALTH SYSTEM INTERVENTIONS

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    Background:. Organizational readiness is an important concept in Implementation Science for which additional study is needed. Health systems regularly adopt new care delivery interventions, and improved understanding of the factors that support organizational readiness will help improve adoption of new interventions. This dissertation examines the characteristics of organizational readiness in the implementation of large-scale health system interventions by assessing the relationship between structural and community characteristics of hospitals and organizational readiness; the relationship of organizational readiness with implementation barriers; and examining the role of organizational readiness in the implementation of an alternate care site (ACS) in response to a pandemic. Methods: We use quantitative data collected as part of the Improving Surgical Care Recovery (ISCR) Program, American Hospital Association survey, and Area Health Resource File to estimate the relationships among organizational readiness, implementation barriers, and structural and community characteristics. We conduct interviews with leaders of the ACS to examine the role organizational readiness played in planning and operating the site. Results: We observe per capita Medicare spending and the percent of a county’s population older than 65 to be positively associated with readiness for ISCR. Several characteristics are associated with implementation barriers, including teaching hospital status. Organizational readiness has some mediating influence in the relationship between structural and community factors and implementation barriers reported at 8 months, but not at other time periods. In the qualitative assessment of organizational readiness for implementing an ACS, we found a high level of commitment and identified seven key themes: Commitment, Resources, Team Dynamics, Expertise, Operational Decisions, Task Clarity, and Lessons Learned. Conclusions: Further understanding how observable characteristics relate to organizational readiness for innovation and interventions can support health system leaders as they plan future large-scale change initiatives. Organizational readiness may play a role in effective management of barriers in later stages of change, but at least in the context of the ISCR program, played less of a role earlier in implementation. Understanding organizational readiness for implementing an ACS offers insights for how it can be enhanced for future public health emergencies and to support large-scale change efforts associated with other healthcare delivery challenges

    Toxoplasma gondii exploits the host ESCRT machinery for parasite uptake of host cytosolic proteins.

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    Toxoplasma gondii is a master manipulator capable of effectively siphoning the resources from the host cell for its intracellular subsistence. However, the molecular underpinnings of how the parasite gains resources from its host remain largely unknown. Residing within a non-fusogenic parasitophorous vacuole (PV), the parasite must acquire resources across the limiting membrane of its replicative niche, which is decorated with parasite proteins including those secreted from dense granules. We discovered a role for the host Endosomal Sorting Complex Required for Transport (ESCRT) machinery in host cytosolic protein uptake by T. gondii by disrupting host ESCRT function. We identified the transmembrane dense granule protein TgGRA14, which contains motifs homologous to the late domain motifs of HIV-1 Gag, as a candidate for the recruitment of the host ESCRT machinery to the PV membrane. Using an HIV-1 virus-like particle (VLP) release assay, we found that the motif-containing portion of TgGRA14 is sufficient to substitute for HIV-1 Gag late domain to mediate ESCRT-dependent VLP budding. We also show that TgGRA14 is proximal to and interacts with host ESCRT components and other dense granule proteins during infection. Furthermore, analysis of TgGRA14-deficient parasites revealed a marked reduction in ingestion of a host cytosolic protein compared to WT parasites. Thus, we propose a model in which T. gondii recruits the host ESCRT machinery to the PV where it can interact with TgGRA14 for the internalization of host cytosolic proteins across the PV membrane (PVM). These findings provide new insight into how T. gondii accesses contents of the host cytosol by exploiting a key pathway for vesicular budding and membrane scission

    The genetic correlation between height and IQ: shared genes or assortative mating?

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    Traits that are attractive to the opposite sex are often positively correlated when scaled such that scores increase with attractiveness, and this correlation typically has a genetic component. Such traits can be genetically correlated due to genes that affect both traits ("pleiotropy") and/or because assortative mating causes statistical correlations to develop between selected alleles across the traits ("gametic phase disequilibrium"). In this study, we modeled the covariation between monozygotic and dizygotic twins, their siblings, and their parents (total N = 7,905) to elucidate the nature of the correlation between two potentially sexually selected traits in humans: height and IQ. Unlike previous designs used to investigate the nature of the height-IQ correlation, the present design accounts for the effects of assortative mating and provides much less biased estimates of additive genetic, non-additive genetic, and shared environmental influences. Both traits were highly heritable, although there was greater evidence for non-additive genetic effects in males. After accounting for assortative mating, the correlation between height and IQ was found to be almost entirely genetic in nature. Model fits indicate that both pleiotropy and assortative mating contribute significantly and about equally to this genetic correlation

    Rapid cloud removal of dimethyl sulfide oxidation products limits SO2 and cloud condensation nuclei production in the marine atmosphere.

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    Oceans emit large quantities of dimethyl sulfide (DMS) to the marine atmosphere. The oxidation of DMS leads to the formation and growth of cloud condensation nuclei (CCN) with consequent effects on Earth's radiation balance and climate. The quantitative assessment of the impact of DMS emissions on CCN concentrations necessitates a detailed description of the oxidation of DMS in the presence of existing aerosol particles and clouds. In the unpolluted marine atmosphere, DMS is efficiently oxidized to hydroperoxymethyl thioformate (HPMTF), a stable intermediate in the chemical trajectory toward sulfur dioxide (SO2) and ultimately sulfate aerosol. Using direct airborne flux measurements, we demonstrate that the irreversible loss of HPMTF to clouds in the marine boundary layer determines the HPMTF lifetime (Ď„HPMTF < 2 h) and terminates DMS oxidation to SO2 When accounting for HPMTF cloud loss in a global chemical transport model, we show that SO2 production from DMS is reduced by 35% globally and near-surface (0 to 3 km) SO2 concentrations over the ocean are lowered by 24%. This large, previously unconsidered loss process for volatile sulfur accelerates the timescale for the conversion of DMS to sulfate while limiting new particle formation in the marine atmosphere and changing the dynamics of aerosol growth. This loss process potentially reduces the spatial scale over which DMS emissions contribute to aerosol production and growth and weakens the link between DMS emission and marine CCN production with subsequent implications for cloud formation, radiative forcing, and climate
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