273 research outputs found

    BEHAVIOUR OF JUVENILE ASIAN ELEPHANTS IN Panicum maximum DOMINA TED GRASSLANDS IN THE UDA WALA WA NATIONAL PARK.

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    Guinea grass (Panicum maximum) dominated grasslands, a major habitat typein the Udawalawa National Park, is frequently occupied by wild elephants.Behaviour of juvenile elephants (4-6 years old) inhabiting the habitat wasstudied from April 2004 to March 2005. Focal animal sampling was employedto quantify behaviour and total time of observation was 3100 minutes.The activity budget of the juveniles comprised of ten behaviour patterns;feeding (44%), resting (24%), locomotion (19%), play (5%), comfort (5%),drinking, social, exploratory, agonistic and anxious. Maximum feeding (55%)and minimum resting (13%) were recorded during late afternoons (1500-1800hrs) whilst maximum resting (37%) and minimum feeding (29%) wererecorded during late mornings (0900-1200 hrs). Locomotion and otherbehaviour patterns did not significantly vary with time. Time spent on feedingwas higher in wet months (47%) than in dry months (39%). Resting wasrelatively higher in dry period (27%) than in wet (21 %). P. maximum was themajor food type consumed throughout the year while they fed on native grassesand herbs to a lesser extent (21-29%). Significant correlations between ambienttemperature and time spent on feeding (r= -0.716) and resting (r = +0.751)were evident.The Department of Wildlife Conservation and the Born Free Foundation, UKare acknowledged.

    Thermal limits of leaf metabolism across biomes

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    High-temperature tolerance in plants is important in a warming world, with extreme heat waves predicted to increase in frequency and duration, potentially leading to lethal heating of leaves. Global patterns of high-temperature tolerance are documented in animals, but generally not in plants, limiting our ability to assess risks associated with climate warming. To assess whether there are global patterns in high-temperature tolerance of leaf metabolism, we quantified Tcrit (high temperature where minimal chlorophyll a fluorescence rises rapidly and thus photosystem II is disrupted) and Tmax (temperature where leaf respiration in darkness is maximal, beyond which respiratory function rapidly declines) in upper canopy leaves of 218 plant species spanning seven biomes. Mean site-based Tcrit values ranged from 41.5 °C in the Alaskan arctic to 50.8 °C in lowland tropical rainforests of Peruvian Amazon. For Tmax, the equivalent values were 51.0 and 60.6 °C in the Arctic and Amazon, respectively. Tcrit and Tmax followed similar biogeographic patterns, increasing linearly (˜8 °C) from polar to equatorial regions. Such increases in high-temperature tolerance are much less than expected based on the 20 °C span in high-temperature extremes across the globe. Moreover, with only modest high-temperature tolerance despite high summer temperature extremes, species in mid-latitude (~20-50°) regions have the narrowest thermal safety margins in upper canopy leaves; these regions are at the greatest risk of damage due to extreme heat-wave events, especially under conditions when leaf temperatures are further elevated by a lack of transpirational cooling. Using predicted heat-wave events for 2050 and accounting for possible thermal acclimation of Tcrit and Tmax, we also found that these safety margins could shrink in a warmer world, as rising temperatures are likely to exceed thermal tolerance limits. Thus, increasing numbers of species in many biomes may be at risk as heat-wave events become more severe with climate change

    Anti-Inflammatory Activity Is a Possible Mechanism by Which the Polyherbal Formulation Comprised of Nigella sativa

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    The present study investigated the anti-inflammatory effects of a polyherbal decoction comprised of Nigella sativa, Hemidesmus indicus, and Smilax glabra in order to justify its claimed antihepatocarcinogenic activity. Activation of hepatic nuclear factor-kappa B (NF-κB), IκB kinase (IKK α/β) proteins, and TNFα and IL-6 expression was investigated in diethylnitrosamine- (DEN-) induced C3H mice-bearing early hepatocarcinogenic changes. Acute phase inflammatory response was evaluated by carrageenan-induced rat paw edema formation. Anti-inflammatory mechanisms were also assessed by determining effect on (a) membrane stabilization, (b) nitric oxide (NO) inhibitory activity, and (c) inhibition of leukocyte migration. A significant inhibition of the paw edema formation was observed in healthy rats as well as in rats bearing early hepatocarcinogenic changes with oral administration of the decoction. As with the positive control, indomethacin (10 mg/kg b.w.) the inhibitory effect was pronounced at 3rd and 4th h after carrageenan injection. A notable IKK α/β mediated hepatic NF-κB inactivation was associated with a significant hepatic TNFα downregulation among mice-bearing hepatocarcinogenic changes subjected to decoction treatment. Inhibition of NO production, leukocyte migration, and membrane stabilization are possible mechanisms by which anti-inflammatory effect is mediated by the decoction. Overall findings imply that anti-inflammatory activity could be one of the mechanisms by which the decoction mediates its antihepatocarcinogenic effects

    Electroplating of CdTe thin films from cadmium sulphate precursor and comparison of layers grown by 3-electrode and 2-electrode systems

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    Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E) and two-electrode (2E) systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system

    Electro-plating and characterisation of cadmium sulphide thin films using ammonium thiosulphate as the sulphur source

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    Cadmium sulphide (CdS) thin films have been successfully prepared from an aqueous electrolyte bath containing CdCl2 and ammonium thiosulphate ((NH4)2S2O3) using electrodeposition technique. The structural, compositional, optical, morphological and electrical properties of these thin films have been characterized using X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy, UV–Vis spectrophotometry, scanning electron microscopy (SEM), atomic force microscopy (AFM), photoelectrochemical cell and D.C. current–voltage (I–V) measurements. The optimum deposition cathodic potential has been observed at 1,455 mV, in a 2-electrode system with respect to carbon anode. Structural analysis using XRD shows a mixture of hexagonal and cubic phases in the as-deposited CdS samples and a phase transformation to the hexagonal structure occurred after heat treatment at 400 °C for 20 min. Optical studies demonstrate an improvement in the band edge, producing 2.42 eV for the band gap of the films after heat treatment. The heat treated CdS thin films show better transmission for wavelengths longer than 500 nm. SEM and AFM show that the heat-treated samples are more uniform, smoother and have larger grain size. Electrical studies confirm that the CdS thin films have n-type electrical conductivity and heat treated CdS thin films have resistivities of the order of 105 Ω cm

    Pattern of pesticide storage before pesticide self-poisoning in rural Sri Lanka

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    <p>Abstract</p> <p>Background</p> <p>Deliberate self-poisoning with agricultural pesticides is the commonest means of suicide in rural Asia. It is mostly impulsive and facilitated by easy access to pesticides. The aim of this large observational study was to investigate the immediate source of pesticides used for self-harm to help inform suicide prevention strategies such as reducing domestic access to pesticides.</p> <p>Methods</p> <p>The study was conducted in a district hospital serving an agricultural region of Sri Lanka. Patients who had self-poisoned with pesticides and were admitted to the adult medical wards were interviewed by study doctors following initial resuscitation to identify the source of pesticides they have ingested.</p> <p>Results</p> <p>Of the 669 patients included in the analysis, 425 (63.5%) were male; the median age was 26 (IQR 20-36). In 511 (76%) cases, the pesticides had been stored either inside or immediately outside the house; among this group only eight patients obtained pesticides that were kept in a locked container. Ten percent (n = 67) of the patients used pesticides stored in the field while 14% (n = 91) purchased pesticides from shops within a few hours of the episode. The most common reasons for choosing the particular pesticide for self-harm were its easy accessibility (n = 311, 46%) or its popularity as a suicide agent in their village (n = 290, 43%).</p> <p>Conclusion</p> <p>Three quarters of people who ingested pesticides in acts of self-harm used products that were available within the home or in close proximity; relatively few patients purchased the pesticide for the act. The study highlights the importance of reducing the accessibility of toxic pesticides in the domestic environment.</p

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

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    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

    Determinants of online shopping among tertiary students in Ghana: An extended technology acceptance model

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    The increasing penetration rate of the internet and technology in the world is quickly promoting online shopping. This has been fueled by growing innovations in the telecommunication and financial sector in an attempt to depeen financial inclusion. Innovations such as mobile money payments systems by mobile telephony companies have contributed to the continuous growth in online shopping amidst and the new generation of consumers who desire richer experiences. This study sought to identify the determinants of online shopping behaviour among tertiary students through the lens of the Technology Acceptance Model (TAM). The study proposed a revised TAM that integrated perceived cost and perceived risk to investigate what determined students online shopping intention and actual use. The survey involved a sample of 580 undergraduate students. The statistical technique used was Structural Equation Modelling-Partial Least Squares (SEM-PLS). The results showed that effect of ease of use on usefulness was very significant as same has been predicted by the Technology Acceptance Model. Among the independent variables, perceived cost (PC) was found to be the most significant factor affecting actual use (AU) of online shopping among students, nonetheless, perceived cost (PC) had no significant effect on purchase intention (PI). Perceived risk (PR) had no significant effect on actual use (AU) however, had a significant effect on purchase intention (PI). The study recommends online sellers to make online shopping efficient and less costive with assured safety and security of transactions as well as the product itself. A set of shopping platform could even be created specifically to give discounts and other offers to students. It also recommends future studies to employ additional determining factors such as the type of product/service, convenience and personal/demographic and geographic factors as influential to students’ online purchasing behaviour. © 2019, © 2019 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license
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