Dengue virus (DENV) infection causes ∼200 million cases of severe flulike illness annually, escalating to life-threatening hemorrhagic fever or shock syndrome in ∼500 000. Although thrombocytopenia ...is typical of both mild and severe diseases, the mechanism triggering platelet reduction is incompletely understood. As a probable initiating event, direct purified DENV-platelet binding was followed in the current study by quantitative reverse transcription-polymerase chain reaction and confirmed antigenically. Approximately 800 viruses specifically bound per platelet at 37°C. Fewer sites were observed at 25°C, the blood bank storage temperature (∼350 sites), or 4°C, known to attenuate virus cell entry (∼200 sites). Dendritic cell–specific intercellular adhesion molecule-3–grabbing nonintegrin (DC-SIGN) and heparan sulfate proteoglycan were implicated as coreceptors because only the combination of anti–DC-SIGN and low-molecular-weight heparin prevented binding. Interestingly, at 37°C and 25°C, platelets replicated the positive sense single-stranded RNA genome of DENV by up to ∼4-fold over 7 days. Further time course experiments demonstrated production of viral NS1 protein, which is known to be highly antigenic in patient serum. The infectivity of DENV intrinsically decayed in vitro, which was moderated by platelet-mediated generation of viable progeny. This was shown using a transcription inhibitor and confirmed by freeze-denatured platelets being incapable of replicating the DENV genome. For the first time, these data demonstrate that platelets directly bind DENV saturably and produce infectious virus. Thus, expression of antigen encoded by DENV is a novel consideration in the pathogen-induced thrombocytopenia mechanism. These results furthermore draw attention to the possibility that platelets may produce permissive RNA viruses in addition to DENV.
•Platelets replicate and produce infectious DENV.•DENV binds directly to platelets using DC-SIGN and heparan sulfate proteoglycan as primary receptors.
We report results of the first comprehensive, high resolution study of the deflections of UHECRs using a realistic model of the Galactic magnetic field and extending to sufficiently low rigidities, ...R≡E/Z≥1018V, to describe Fe in the UHE energy range above ∼55 EeV, or the mixed composition reported by the Pierre Auger Collaboration at the energy of the observed dipole anisotropy. We use the Jansson-Farrar (JF12) model, which has both a large scale coherent and a structured random component, and determine deflections for fifteen rigidities from 1018.0 to 1020.0 V, for two different coherence length choices for the random component, Lcoh=30 pc and 100 pc. We also check the sensitivity of UHECR deflections to the particular realization of the random field, for 3 rigidity values. For each rigidity and field model studied, the UHECR arrival direction distribution is determined for an arbitrary source direction, by inverting the trajectories of >5×107 isotropically-distributed anti-CRs of the given rigidity, which we backtrack using the code CRT. We present skyplots and tables characterizing the arrival directions, for representative 1o sources. Except at high rigidity, the pattern of multiple images is very complex and depends strongly on the coherence length and source direction. For almost all sources, average deflections grow rapidly as the rigidity falls below 10 EV and deflections commonly are greater than 90ˆ. Magnification and demagnification can be strong at almost all rigidities, and varies significantly with source direction. Much of the extragalactic celestial sphere, behind and south of the Galactic Center, cannot be seen in UHECRs below 10 EV. One empirical regularity is that the average deflection of UHECRs from a given source, while growing with decreasing rigidity and depending on source direction and Lcoh, is about twice as large as the RMS angular spread about the mean arrival direction (centroid), independently of source direction, rigidity or Lcoh, albeit with outliers. The pattern of deflections obtained with the coherent field alone can be significantly different than with the complete field model, even as regards the position of the centroid, for some source directions and rigidities. Multiple images, sometimes very widely separated, are common for small coherence length, especially for low rigidity.
We examine the seasonality of asthma-related hospital admissions in Melbourne, Australia, in particular the contribution and predictability of episodic thunderstorm asthma. Using a time-series ...ecological approach based on asthma admissions to Melbourne metropolitan hospitals, we identified seasonal peaks in asthma admissions that were centred in late February, June and mid-November. These peaks were most likely due to the return to school, winter viral infections and seasonal allergies, respectively. We performed non-linear statistical regression to predict daily admission rates as functions of the seasonal cycle, weather conditions, reported thunderstorms, pollen counts and air quality. Important predictor variables were the seasonal cycle and mean relative humidity in the preceding two weeks, with higher humidity associated with higher asthma admissions. Although various attempts were made to model asthma admissions, none of the models explained substantially more variation above that associated with the annual cycle. We also identified a list of high asthma admissions days (HAADs). Most HAADs fell in the late-February return-to-school peak and the November allergy peak, with the latter containing the greatest number of daily admissions. Many HAADs in the spring allergy peak may represent episodes of thunderstorm asthma, as they were associated with rainfall, thunderstorms, high ambient grass pollen levels and high humidity, a finding that suggests thunderstorm asthma is a recurrent phenomenon in Melbourne that occurs roughly once per five years. The rarity of thunderstorm asthma events makes prediction challenging, underscoring the importance of maintaining high standards of asthma management, both for patients and health professionals, especially during late spring and early summer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) generates digital elevation models (DEMs) that range from the local to global scale. ...Collectively, these DEMs are essential to determining the timing and extent of coastal inundation and improving community preparedness, event forecasting, and warning systems. We initiated a comprehensive framework at NCEI, the Continuously Updated DEM (CUDEM) Program, with seamless bare-earth, topographic-bathymetric and bathymetric DEMs for the entire United States (U.S.) Atlantic and Gulf of Mexico Coasts, Hawaii, American Territories, and portions of the U.S. Pacific Coast. The CUDEMs are currently the highest-resolution, seamless depiction of the entire U.S. Atlantic and Gulf Coasts in the public domain; coastal topographic-bathymetric DEMs have a spatial resolution of 1/9th arc-second (~3 m) and offshore bathymetric DEMs coarsen to 1/3rd arc-second (~10 m). We independently validate the land portions of the CUDEMs with NASA’s Advanced Topographic Laser Altimeter System (ATLAS) instrument on board the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) observatory and calculate a corresponding vertical mean bias error of 0.12 m ± 0.75 m at one standard deviation, with an overall RMSE of 0.76 m. We generate the CUDEMs through a standardized process using free and open-source software (FOSS) and provide open-access to our code repository. The CUDEM framework consists of systematic tiled geographic extents, spatial resolutions, and horizontal and vertical datums to facilitate rapid updates of targeted areas with new data collections, especially post-storm and tsunami events. The CUDEM framework also enables the rapid incorporation of high-resolution data collections ingested into local-scale DEMs into NOAA NCEI’s suite of regional and global DEMs. Future research efforts will focus on the generation of additional data products, such as spatially explicit vertical error estimations and morphologic change calculations, to enhance the utility and scientific benefits of the CUDEM Program.
Analyses of phylogenetic topology and estimates of divergence timing have facilitated a reconstruction of Madagascar's colonization events by vertebrate animals, but that information alone does not ...reveal the major factors shaping the island's biogeographic history. Here, we examine profiles of Malagasy vertebrate clades through time within the context of the island's paleogeographical evolution to determine how particular events influenced the arrival of the island's extant groups. First we compare vertebrate profiles on Madagascar before and after selected events; then we compare tetrapod profiles on Madagascar to contemporary tetrapod compositions globally. We show that changes from the Mesozoic to the Cenozoic in the proportions of Madagascar's tetrapod clades (particularly its increase in the representation of birds and mammals) are tied to changes in their relative proportions elsewhere on the globe. Differences in the representation of vertebrate classes from the Mesozoic to the Cenozoic reflect the effects of extinction (i.e., the non-random susceptibility of the different vertebrate clades to purported catastrophic global events 65 million years ago), and new evolutionary opportunities for a subset of vertebrates with the relatively high potential for transoceanic dispersal potential. In comparison, changes in vertebrate class representation during the Cenozoic are minor. Despite the fact that the island's isolation has resulted in high vertebrate endemism and a unique and taxonomically imbalanced extant vertebrate assemblage (both hailed as testimony to its long isolation), that isolation was never complete. Indeed, Madagascar's extant tetrapod fauna owes more to colonization during the Cenozoic than to earlier arrivals. Madagascar's unusual vertebrate assemblage needs to be understood with reference to the basal character of clades originating prior to the K-T extinction, as well as to the differential transoceanic dispersal advantage of other, more recently arriving clades. Thus, the composition of Madagascar's endemic vertebrate assemblage itself provides evidence of the island's paleogeographic history.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Who hunts lemurs and why they hunt them Borgerson, Cortni; McKean, Margaret A.; Sutherland, Michael R. ...
Biological conservation,
20/May , Letnik:
197
Journal Article
Recenzirano
The main threats to lemurs are habitat loss and hunting. Conservation policies often assume that people will decrease lemur hunting if they understand government prohibitions on hunting, are educated ...and/or involved in ecotourism, have access to affordable meat, and/or are healthy and financially secure. Yet these assumptions are often not well tested where conservation policies are implemented. We interviewed every member of a focal village in one of the most biodiverse places on earth, the Masoala peninsula of Madagascar. The factors that best predicted the decision to hunt lemurs were poverty, poor health, and child malnutrition. Knowledge of laws, level of education, involvement in ecotourism, traditional cultural values, taste preferences, opportunity, and human–wildlife conflict had no impact on lemur hunting. Our results suggest that the welfare of humans and lemurs are linked. The key to discouraging illegal hunting and improving the viability of Endangered lemur populations may be improving rural human health and welfare.
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•Developing sound lemur conservation policy requires knowing why lemurs are hunted.•We test eleven popular hypotheses purporting to explain illegal hunting of lemurs.•High education, knowledge of laws, and ecotourism do not reduce illegal hunting.•Poverty, poor health, and child malnutrition best predict lemur hunting.•Improving human health and welfare may be the key to discouraging illegal hunting.
Fundamental disagreements remain regarding the relative importance of climate change and human activities as triggers for Madagascar's Holocene megafaunal extinction. We use stable isotope data from ...stalagmites from northwest Madagascar coupled with radiocarbon and butchery records from subfossil bones across the island to investigate relationships between megafaunal decline, climate change, and habitat modification. Archaeological and genetic evidence support human presence by 2000 years Before Common Era (BCE). Megafaunal decline was at first slow; it hastened at ∼700 Common Era (CE) and peaked between 750 and 850 CE, just before a dramatic vegetation transformation in the northwest that resulted in the replacement of C3 woodland habitat with C4 grasslands, during a period of heightened monsoonal activity. Cut and chop marks on subfossil lemur bones reveal a shift in primary hunting targets from larger, now-extinct species prior to ∼900 CE, to smaller, still-extant species afterwards. By 1050 CE, megafaunal populations had essentially collapsed. Neither the rapid megafaunal decline beginning ∼700 CE, nor the dramatic vegetation transformation in the northwest beginning ∼890 CE, was influenced by aridification. However, both roughly coincide with a major transition in human subsistence on the island from hunting/foraging to herding/farming.
We offer a new hypothesis, which we call the “Subsistence Shift Hypothesis,” to explain megafaunal decline and extinction in Madagascar. This hypothesis acknowledges the importance of wild-animal hunting by early hunter/foragers, but more critically highlights negative impacts of the shift from hunting/foraging to herding/farming, settlement by new immigrant groups, and the concomitant expansion of the island's human population. The interval between 700 and 900 CE, when the pace of megafaunal decline quickened and peaked, coincided with this economic transition. While early megafaunal decline through hunting may have helped to trigger the transition, there is strong evidence that the economic shift itself hastened the crash of megafaunal populations.
Background. Despite the high prevalence of patient-reported antibiotic allergy (so-called antibiotic allergy labels AALs) and their impact on antibiotic prescribing, incorporation of antibiotic ...allergy testing (AAT) into antimicrobial stewardship (AMS) programs (AAT-AMS) is not widespread. We aimed to evaluate the impact of an AAT-AMS program on AAL prevalence, antibiotic usage, and appropriateness of prescribing. Methods. AAT-AMS was implemented at two large Australian hospitals during a 14-month period beginning May 2015. Baseline demographics, AAL history, age-adjusted Charlson comorbidity index, infection history, and antibiotic usage for 12 months prior to testing (pre–AAT-AMS) and 3 months following testing (post–AAT-AMS) were recorded for each participant. Study outcomes included the proportion of patients who were "de-labeled" of their AAL, spectrum of antibiotic courses pre– and post–AAT-AMS, and antibiotic appropriateness (using standard definitions). Results. From the 118 antibiotic allergy—tested patients, 226 AALs were reported (mean, 1.91/patient), with 53.6% involving 1 or more penicillin class drug. AAT-AMS allowed AAL de-labeling in 98 (83%) patients–56% (55/98) with all AALs removed. Post– AAT, prescribing of narrow-spectrum penicillins was more likely (adjusted odds ratio aOR, 2.81, 95% confidence interval CI, 1.45–5.42), as was narrow-spectrum β-lactams (aOR, 3.54; 95% CI, 1.98–6.33), and appropriate antibiotics (aOR, 12.27; 95% CI, 5.00–30.09); and less likely for restricted antibiotics (aOR, 0.16; 95% CI, 09–.29), after adjusting for indication, Charlson comorbidity index, and care setting. Conclusions. An integrated AAT-AMS program was effective in both de-labeling of AALs and promotion of improved antibiotic usage and appropriateness, supporting the routine incorporation of AAT into AMS programs.
How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break ...that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal from the Paleocene onward, reaching the lowest levels after the mid-Miocene. This finding is consistent with a paleoceanographic model Ali JR, Huber M (2010) Nature 463:653–656 that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming from Africa, followed by a reconfiguration to present-day flow 15–20 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland.
Wind wave observations in shallow coastal waters are essential for calibrating, validating, and improving numerical wave models to predict sediment transport, shoreline change, and coastal hazards ...such as beach erosion and oceanic inundation. Although ocean buoys and satellites provide near-global coverage of deep-water wave conditions, shallow-water wave observations remain sparse and often inaccessible. Nearshore wave conditions may vary considerably alongshore due to coastline orientation and shape, bathymetry and islands. We present a growing dataset of in-situ wave buoy observations from shallow waters (<35 m) in southeast Australia that comprises over 7,000 days of measurements at 20 locations. The moored buoys measured wave conditions continuously for several months to multiple years, capturing ambient and storm conditions in diverse settings, including coastal hazard risk sites. The dataset includes tabulated time series of spectral and time-domain parameters describing wave height, period and direction at half-hourly temporal resolution. Buoy displacement and wave spectra data are also available for advanced applications. Summary plots and tables describing wave conditions measured at each location are provided.
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