78 research outputs found

    Variation in adult life-history and stress resistance across five species of Drosophila

    Get PDF
    Dry weight at eclosion, adult lifespan, lifetime fecundity, lipid and carbohydrate content at eclosion, and starvation and desiccation resistance at eclosion were assayed on a long-term laboratory population of Drosophila melanogaster, and one recently wild-caught population each of four other species of Drosophila, two from themelanogaster and two from theimmigrans species group. The relationships among trait means across the five species did not conform to expectations based on correlations among these traits inferred from selection studies on D. melanogaster. In particular, the expected positive relationships between fecundity and size/lipid content, lipid content and starvation resistance, carbohydrate (glycogen) content and desiccation resistance, and the expected negative relationship between lifespan and fecundity were not observed. Most traits were strongly positively correlated between sexes across species, except for fractional lipid content and starvation resistance per microgram lipid. For most traits, there was evidence for significant sexual dimorphism but the degree of dimorphism did not vary across species except in the case of adult lifespan, starvation resistance per microgram lipid, and desiccation resistance per microgram carbohydrate. Overall,D. nasuta nasuta andD. sulfurigaster neonasuta (immigrans group) were heavier at eclosion than themelanogaster group species, and tended to have somewhat higher absolute lipid content and starvation resistance. Yet, these twoimmigrans group species were shorter-lived and had lower average daily fecundity than themelanogaster group species. The smallest species, D. malerkotliana (melanogaster group), had relatively high daily fecundity, intermediate lifespan and high fractional lipid content, especially in females. D. ananassae (melanogaster group) had the highest absolute and fractional carbohydrate content, but its desiccation resistance per microgram carbohydrate was the lowest among the five species. In terms of overall performance, the laboratory population of D. melanogaster was clearly superior, under laboratory conditions, to the other four species if adult lifespan, lifetime fecundity, average daily fecundity, and absolute starvation and desiccation resistance are considered. This finding is contrary to several recent reports of substantially higher adult lifespan and stress resistance in recently wild-caught flies, relative to flies maintained for a long time in discretegeneration laboratory cultures. Possible explanations for these apparent anomalies are discussed in the context of the differing selection pressures likely to be experienced by Drosophila populations in laboratory versus wild environments

    Correlates of sexual dimorphism for dry weight and development time in five species of Drosophila

    Get PDF
    Pre-adult development time, dry weight at eclosion, and daily fecundity over the first 10 days of adult life were measured in five species of Drosophila from the melanogaster and immigrans species groups. Overall, the three species of the melanogaster group (D. melanogaster, D. ananassae, D. malerkotliana) developed faster, were lighter at eclosion, and produced more eggs per unit weight at eclosion than the two species of the immigrans group (D. n. nasuta, D. sulfurigaster neonasuta). The degree of sexual dimorphism in dry weight was greater than that in development time, but did not vary significantly among species, and was not correlated with fecundity, contrary to expectations that sexual selection for increased fecundity drives sexual size dimorphism in Drosophila. The degree of dimorphism in development time was significantly correlated with dry weight and fecundity, with lighter species tending to be more dimorphic for development time as well as more fecund, both in absolute terms and in terms of fecundity per unit weight. The results suggest that our understanding of the evolutionary forces maintaining sexual size dimorphism in Drosophila will probably benefit from more detailed studies on the correlates of sexual dimorphism within and among Drosophila species, and on the shape of reaction norms for the degree of sexual dimorphism across different levels of ecologically relevant environmental variables

    Bio-Synthesis of copper nanoparticles (CuNPs) using Garlic extract to investigate antibacterial activity

    Get PDF
    Bio-synthesis of metal nanoparticles (CuNPs) is regarded as one of the recently developed, economic and environmentally benign method. In the present investigation, Copper nanoparticles were synthesized reacting garlic (Allium sativum) extract with Copper Sulphate (CuSO4∙5H2O) solution over magnetic stirrer at 80 °C for 1 hour. So-prepared CuNPs were studied by observing the color change at various time intervals.  Further, the nanoparticles were characterized using UV-Visible spectroscopy, Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). The results of UV-Vis   spectroscopy   clearly showed presence of absorption peak at 595 nm which confirmed   the   formation   of   copper nanoparticles. Likewise, the EDX spectrum depicts the presence of optical band at 8 eV which is the characteristic peak of Copper consisting of 38.747 % by weight and FTIR spectra revealed presence of various phytochemicals possessing characteristic functional groups such as carbonyl and phenolic at the surface of CuNPs. Thus, natural products available in the garlic extract help in reduction and stabilization of Copper nanoparticles.  The antibacterial activity of Copper nanoparticles was investigated against Gram +ve (Staphylococcus aureus) and Gram –ve bacteria (Escherichia coli) using Agarwell diffusion method. The results of antibacterial test showed that CuNPs were found to be much sensitive towards Gram –ve bacteria compared to gram +ve bacteria.  BIBECHANA 17 (2020) 12-18  

    Bio-Synthesis of copper nanoparticles (CuNPs) using Garlic extract to investigate antibacterial activity

    Get PDF
    Bio-synthesis of metal nanoparticles (CuNPs) is regarded as one of the recently developed, economic and environmentally benign method. In the present investigation, Copper nanoparticles were synthesized reacting garlic (Allium sativum) extract with Copper Sulphate (CuSO4∙5H2O) solution over magnetic stirrer at 80 °C for 1 hour. So-prepared CuNPs were studied by observing the color change at various time intervals.  Further, the nanoparticles were characterized using UV-Visible spectroscopy, Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). The results of UV-Vis   spectroscopy   clearly showed presence of absorption peak at 595 nm which confirmed   the   formation   of   copper nanoparticles. Likewise, the EDX spectrum depicts the presence of optical band at 8 eV which is the characteristic peak of Copper consisting of 38.747 % by weight and FTIR spectra revealed presence of various phytochemicals possessing characteristic functional groups such as carbonyl and phenolic at the surface of CuNPs. Thus, natural products available in the garlic extract help in reduction and stabilization of Copper nanoparticles.  The antibacterial activity of Copper nanoparticles was investigated against Gram +ve (Staphylococcus aureus) and Gram –ve bacteria (Escherichia coli) using Agarwell diffusion method. The results of antibacterial test showed that CuNPs were found to be much sensitive towards Gram –ve bacteria compared to gram +ve bacteria.  BIBECHANA 17 (2020) 12-18  

    Time to death in the presence of E. coli: a mass-scale method for assaying pathogen resistance in Drosophila

    Get PDF
    This article does not have an abstract

    Machine Learning Approaches for Short-Range Wind Power Estimation: A Perspective

    Get PDF
    The evolution of wind energy production, especially in near and offshore farms, has seen significant advancements due to the integration of novel technologies and the reduction in economic costs. This paper reviews the work in the domain of wind power estimation, emphasizing the innovative approaches leveraging satellite data and artificial intelligence (AI) methodologies. A notable method integrates Sentinel satellite imagery analysis in a two-phased approach, combined with machine learning techniques, to forecast wind speed. This method utilizes sentinel-1 and sentinel-2 satellite images for wind speed and bathymetry analysis, respectively. Furthermore, a hybrid forecasting model, comprising the generalized regression neural network (GRNN) and the whale optimization algorithm (WOA), has been introduced. Another pivotal advancement comes from the National Center for Atmospheric Research (NCAR), which has revamped its wind power forecasting system. This enhancement focuses on short-term forecasting, uncertainty quantification in wind speed prediction, and the prediction of extreme events like icing. The integration of numerical weather prediction with machine-learning methods, such as the fuzzy logic artificial intelligence system, has further elevated the accuracy and efficiency of these forecasting models. Collectively, these advancements offer a comprehensive perspective on the future of shortrange wind power estimation

    Mapping regional risks from climate change for rainfed rice cultivation in India

    Get PDF
    Global warming is predicted to increase in the future, with detrimental consequences for rainfed crops that are dependent on natural rainfall (i.e. non-irrigated). Given that many crops grown under rainfed conditions support the livelihoods of low-income farmers, it is important to highlight the vulnerability of rainfed areas to climate change in order to anticipate potential risks to food security. In this paper, we focus on India, where ~ 50% of rice is grown under rainfed conditions, and we employ statistical models (climate envelope models (CEMs) and boosted regression trees (BRTs)) to map changes in climate suitability for rainfed rice cultivation at a regional level (~ 18 × 18 km cell resolution) under projected future (2050) climate change (IPCC RCPs 2.6 and 8.5, using three GCMs: BCC-CSM1.1, MIROC-ESM-CHEM, and HadGEM2-ES). We quantify the occurrence of rice (whether or not rainfed rice is commonly grown, using CEMs) and rice extent (area under cultivation, using BRTs) during the summer monsoon in relation to four climate variables that affect rice growth and yield namely ratio of precipitation to evapotranspiration (PER), maximum and minimum temperatures (Tmax and Tmin), and total rainfall during harvesting. Our models described the occurrence and extent of rice very well (CEMs for occurrence, ensemble AUC = 0.92; BRTs for extent, Pearson's r = 0.87). PER was the most important predictor of rainfed rice occurrence, and it was positively related to rainfed rice area, but all four climate variables were important for determining the extent of rice cultivation. Our models project that 15%–40% of current rainfed rice growing areas will be at risk (i.e. decline in climate suitability or become completely unsuitable). However, our models project considerable variation across India in the impact of future climate change: eastern and northern India are the locations most at risk, but parts of central and western India may benefit from increased precipitation. Hence our CEM and BRT models agree on the locations most at risk, but there is less consensus about the degree of risk at these locations. Our results help to identify locations where livelihoods of low-income farmers and regional food security may be threatened in the next few decades by climate changes. The use of more drought-resilient rice varieties and better irrigation infrastructure in these regions may help to reduce these impacts and reduce the vulnerability of farmers dependent on rainfed cropping

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

    Get PDF
    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
    corecore