2,649 research outputs found

    Meteorological conditions during the formation of ice on aircraft

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    These are the results of a number of records recently secured from autographic meteorological instruments mounted on airplanes at times when ice formed. Ice is found to collect on an airplane only when the airplane is in some form of visible moisture, such as cloud, fog, mist, rain. etc., and the air temperature is within certain critical limits. Described here are the characteristics of clear ice and rime ice and the specific types of hazards they present to airplanes and lighter than air vehicles. The weather records are classified according to the two general types of formation (clear ice and rime) together with the respective temperatures, relative humidities, clouds, and elevations above ground at which formations occurred. This classification includes 108 cases where rime formed, 43 cases in which clear ice formed, and 4 cases when both rime and clear ice formed during the same flight. It is evident from the above figures that there was a preponderance of rime by the ratio of 2.5 to 1, while in only a few cases both types of ice formation occurred during the same flight

    The Diversity of Poisonous Plant Patches in the Arid Rangelands of Namaqualand, South Africa

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    The Namaqualand region in South Africa is part of the richest arid biodiversity hotspot in the world. Plant distribution and diversity here are impacted by various biophysical and anthropogenic factors. In these landscapes, poisonous plant patches, which pose serious threats to livestock, are widespread but their contribution to the regions biodiversity are not fully understood. This study assessed their plant diversity and compared its matrix. This study was conducted in the semi-arid to arid Steinkopf pastoral area located in Namaqualand where livestock is still herded daily. Twenty-five paired sites were selected based on the dominance of poisonous plants within the genera Tylecodon, Euphorbia and Adromischus. Within these sites, the number and abundance of different plant species were recorded and categorised into different plant functional types. Results showed a significant difference in Shannon Wiener plant diversity where poisonous plant patches displayed a greater diversity compared to sites sampled in the matrix. We interpret these findings as a consequence of herding in the region, where herders do not allow their animals to graze on or near poisonous plant patches. As such, palatable plants, which are absent or low in abundance in the surrounding landscape have a refuge where they can survive and set seed. This study provides evidence that the ethnobotanical knowledge of herders and palette of livestock are also major contributors to the spatial distribution and diversity of plant species in the arid biodiversity hotspot

    Polarization of superfluid turbulence

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    We show that normal fluid eddies in turbulent helium II polarize the tangle of quantized vortex lines present in the flow, thus inducing superfluid vorticity patterns similar to the driving normal fluid eddies. We also show that the polarization is effective over the entire inertial range. The results help explain the surprising analogies between classical and superfluid turbulence which have been observed recently.Comment: 3 figure

    Non-communicable diseases in the Western Area District, Sierra Leone, before and during the Ebola outbreak.

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    Setting: Twenty-seven peripheral health units, five secondary hospitals and one tertiary hospital, Western Area District, Sierra Leone. Objectives: To describe reporting systems, monthly attendances and facility-based patterns of six non-communicable diseases (NCDs) in the pre-Ebola and Ebola virus disease outbreak periods. Design: A cross-sectional study using programme data. Results: Reporting was 89% complete on the six selected NCDs pre-Ebola and 86% during the Ebola outbreak (P < 0.01). Overall, marked declining trends in NCDs were reported during the Ebola period, with a monthly mean of 342 cases pre-Ebola and 164 during the Ebola outbreak. The monthly mean number of cases per disease in the pre-Ebola and Ebola outbreak periods was respectively 228 vs. 85 for hypertension, 43 vs. 27 for cardiovascular diseases, 36 vs. 18 for diabetes and 25 vs. 29 for peptic ulcer disease; this last condition increased during the outbreak. There were higher proportions of NCDs among females during the Ebola outbreak compared with the pre-Ebola period. Except for peptic ulcer disease, the number of patients with NCDs declined by 25% in peripheral health units, 91% in the secondary hospitals and 70% in the tertiary hospital between the pre-Ebola and the Ebola outbreak periods. Conclusion: Comprehensive reporting of NCDs was suboptimal, and declined during the Ebola epidemic. There were decreases in reported attendances for NCDs between the pre-Ebola and the Ebola outbreak periods, which were even more marked in the hospitals. This study has important policy implications

    Avaliação do desempenho de fungos entomopatogênicos sobre fêmeas de Dactylopius opuntiae (Hemiptera: dactylopiidae) em condições de laboratório.

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    O OBJETIVO DESTE TRABALHO FOI INVESTIGAR O POTENCIAL DOS FUNGOS ENTOMOPATOGÊNICOS NO CONTROLE DE D. OPUNTIAE.Resumo 1669-1

    Machine Learning-Based Prediction of Masked Hypertension Among Children With Chronic Kidney Disease

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    BACKGROUND: Ambulatory blood pressure monitoring (ABPM) is routinely performed in children with chronic kidney disease to identify masked hypertension, a risk factor for accelerated chronic kidney disease progression. However, ABPM is burdensome, and developing an accurate prediction of masked hypertension may allow using ABPM selectively rather than routinely. METHODS: To create a prediction model for masked hypertension using clinic blood pressure (BP) and other clinical characteristics, we analyzed 809 ABPM studies with nonhypertensive clinic BP among the participants of the Chronic Kidney Disease in Children study. RESULTS: Masked hypertension was identified in 170 (21.0%) observations. We created prediction models for masked hypertension via gradient boosting, random forests, and logistic regression using 109 candidate predictors and evaluated its performance using bootstrap validation. The models showed CONCLUSIONS: ABPM could be used selectively in those with low clinic BP, for example, systolic BPBPpercentiles, although careful assessment is warranted as masked hypertension was not completely absent even in this subgroup. Above these clinic BP levels, routine ABPM remains recommended

    Tools for delivering entomopathogenic fungi to malaria mosquitoes: effects of delivery surfaces on fungal efficacy and persistence.

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    BACKGROUND\ud \ud Entomopathogenic fungi infection on malaria vectors increases daily mortality rates and thus represents a control measure that could be used in integrated programmes alongside insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS). Before entomopathogenic fungi can be integrated into control programmes, an effective delivery system must be developed.\ud \ud METHODS\ud \ud The efficacy of Metarhizium anisopliae ICIPE-30 and Beauveria bassiana I93-825 (IMI 391510) (2 × 10(10) conidia m(-2)) applied on mud panels (simulating walls of traditional Tanzanian houses), black cotton cloth and polyester netting was evaluated against adult Anopheles gambiae sensu stricto. Mosquitoes were exposed to the treated surfaces 2, 14 and 28 d after conidia were applied. Survival of mosquitoes was monitored daily.\ud \ud RESULTS\ud \ud All fungal treatments caused a significantly increased mortality in the exposed mosquitoes, descending with time since fungal application. Mosquitoes exposed to M. anisopliae conidia on mud panels had a greater daily risk of dying compared to those exposed to conidia on either netting or cotton cloth (p < 0.001). Mosquitoes exposed to B. bassiana conidia on mud panels or cotton cloth had similar daily risk of death (p = 0.14), and a higher risk than those exposed to treated polyester netting (p < 0.001). Residual activity of fungi declined over time; however, conidia remained pathogenic at 28 d post application, and were able to infect and kill 73 - 82% of mosquitoes within 14 d.\ud \ud CONCLUSION\ud \ud Both fungal isolates reduced mosquito survival on immediate exposure and up to 28 d after application. Conidia were more effective when applied on mud panels and cotton cloth compared with polyester netting. Cotton cloth and mud, therefore, represent potential substrates for delivering fungi to mosquitoes in the field
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