1,778 research outputs found

    Tidal Influence On The Physico-Chemical Parameters, Temporal and Spatial Distribution Of Zooplankton in Langat River-Estuarine Area, Malaysia

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    The objectives of present study were to study the water quality, zooplankton distribution and its community structure along a salinity gradient in Langat river estuarine system (20 46'N, 1010 26' E), during low and high tides. Five sampling stations from the coastal area to the upstream were chosen for this study. Station 1 was in the coastal area while Station 5 was at the most upstream, the rest of the Stations (Stations 2,3 and 4) are located in between, passing along the river gradient. Zooplankton and water samples were collected and analyzed monthly for a period of 12 months (January to December 2003). The water quality, nutrients and zooplankton distribution changed according to the stations and tides. The mean salinity ranged from 32.94k1.20 PSU in coastal waters to 27.78k1.21 PSU in upstream station during high tide. During low tide, the mean salinity in the most upstream station was as low as 1.00k0.90 PSU. Higher Dissolved Oxygen values ranged (means of 5.84k0.35 to 7.09k0.13 mgL-1) during high tide and it decreased (means of 3.91k0.71 to 5.22k0.71 mgL-1) during low tide. On the other hand, the nutrients such as total ammonia nitrogen (ranged from 0.0014k0.001 mgL-1 to 2.5714k0.980 mgL-I), nitrite+nitrate-nitrogen (ranged from 0.0021k0.001 mgL-1 to 0.8100k0.211 mgL-1) and total phosphorus (ranged from 0.0712k0.024 mgL-1 to O.867Ok 0.3241 mgL-l) showed increasing trend from the coastal areas to the upstream. The highest chlorophyll a was recorded at Station 3 with mean values of 10.27k0.84 pgL-I and 3.94k1.06 pgL-1 during high and low tide, respectively. The mean zooplankton density was lowest in the coastal areas (16.21 x 103 k4679.07 individuals m-3) and highest in Station 4 with a mean value 119.81 x 103k43338.73 individuals m-3 during high tide. Copepods dominated zooplankton populations contributing >80% in all the stations throughout the sampling period. The other zooplankton groups such as cnidarians, appendicularians, polychaetes, ostracods, chaetognaths and shrimp larva were distributed in coastal estuarine areas whereas echinoderm larvae were restricted to coastal waters and cladocerans were found only at the upstream stations (Stations 3-5).This study recorded 50 species of copepods which was dominated by the calanoids, Acartia spinicauda, A. amboinensis and A. erythraea accounting for 28%, 18% and 11% of the total copepod populations, respectively. High species diversity occurred in Station 1 decreasing towards the upstream. Species diversity varied depending on the tides, being higher during high tides and than low tides. Some copepod species were highly restricted to the high salinity levels (>30 PSU) while some species could tolerate wide range of salinity from 5 - >30 PSU. Major stenohaline species was Oithona simplex and major euryhaline species were Acartia spinicauda, A. amboinensis and A. erythraea. Zooplankton biomass study showed the highest in station 3 (dry weight 6l2.3Of 26.31 mg m-3 high tide) and lowest in Station 2 (150.051t 54.71 mg m-3 during low tide). This study showed that water quality, nutrient concentrations and the distribution of zooplankton varied according to tides, where high tides resulted in better water quality, higher zooplankton density and higher species diversity compared to low tides. On the other hand, water quality was better and species diversity higher in coastal areas compared to other stations throughout the sampling period regardless of tides

    Remote sensing and hydrologic models for performance assessment in Sirsa Irrigation Circle, India

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    Irrigation management / Irrigation systems / Irrigation canals / Performance evaluation / Remote sensing / GIS / Models / Irrigated farming / Hydrology / Satellite surveys / Irrigation scheduling / Evapotranspiration / India

    ASASSN-18di: discovery of a ΔV10ΔV \sim 10 flare on a mid-M dwarf

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    We report and characterize a white-light superflare on a previously undiscovered M dwarf detected by the ASAS-SN survey. Employing various color-magnitude and color-spectral type relationships, we estimate several stellar parameters, including the quiescent V-band magnitude, from which we derive a flare amplitude of ΔV10\Delta V \sim 10. We determine an r-band absolute magnitude of Mr=11.4M_{r} = 11.4, consistent with a mid-M dwarf, and an approximate distance to the source of 2.22.2 kpc. Using classical-flare models, we infer a flare energy of EV(4.1±2.2)×1036E_{V} \simeq (4.1\pm 2.2)\times 10^{36} ergs, making this one of the strongest flares documented on an M dwarf

    EQ-5D-3L Derived Population Norms for Health Related Quality of Life in Sri Lanka

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    Background Health Related Quality of Life (HRQoL) is an important outcome measure in health economic evaluation that guides health resource allocations. Population norms for HRQoL are an essential ingredient in health economics and in the evaluation of population health. The aim of this study was to produce EQ-5D-3L-derived population norms for Sri Lanka. Method A population sample (n =  780) was selected from four districts of Sri Lanka. A stratified cluster sampling approach with probability proportionate to size was employed. Twenty six clusters of 30 participants each were selected; each participant completed the EQ-5D-3L in a face-to-face interview. Utility weights for their EQ-5D-3L health states were assigned using the Sri Lankan EQ-5D-3L algorithm. The population norms are reported by age and socio-economic variables. Results The EQ-5D-3L was completed by 736 people, representing a 94% response rate. Sixty per cent of the sample reported being in full health. The percentage of people responding to any problems in the five EQ-5D-3L dimensions increased with age. The mean EQ-5D-3L weight was 0.85 (SD 0.008; 95%CI 0.84-0.87). The mean EQ-5D-3L weight was significantly associated with age, housing type, disease experience and religiosity. People above 70 years of age were 7.5 times more likely to report mobility problems and 3.7 times more likely to report pain/discomfort than those aged 18-29 years. Those with a tertiary education were five times less likely to report any HRQoL problems than those without a tertiary education. A person living in a shanty was 4.3 more likely to have problems in usual activities than a person living in a single house. Conclusion The population norms in Sri Lanka vary with socio-demographic characteristics. The socioeconomically disadvantaged have a lower HRQoL. The trends of population norms observed in this lower middle income country were generally similar to those previously reported in high income countries

    Structural insights into Clostridium perfringens delta toxin pore formation

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    Clostridium perfringens Delta toxin is one of the three hemolysin-like proteins produced by C. perfringens type C and possibly type B strains. One of the others, NetB, has been shown to be the major cause of Avian Nectrotic Enteritis, which following the reduction in use of antibiotics as growth promoters, has become an emerging disease of industrial poultry. Delta toxin itself is cytotoxic to the wide range of human and animal macrophages and platelets that present GM2 ganglioside on their membranes. It has sequence similarity with Staphylococcus aureus β-pore forming toxins and is expected to heptamerize and form pores in the lipid bilayer of host cell membranes. Nevertheless, its exact mode of action remains undetermined. Here we report the 2.4 Å crystal structure of monomeric Delta toxin. The superposition of this structure with the structure of the phospholipid-bound F component of S. aureus leucocidin (LukF) revealed that the glycerol molecules bound to Delta toxin and the phospholipids in LukF are accommodated in the same hydrophobic clefts, corresponding to where the toxin is expected to latch onto the membrane, though the binding sites show significant differences. From structure-based sequence alignment with the known structure of staphylococcal α-hemolysin, a model of the Delta toxin pore form has been built. Using electron microscopy, we have validated our model and characterized the Delta toxin pore on liposomes. These results highlight both similarities and differences in the mechanism of Delta toxin (and by extension NetB) cytotoxicity from that of the staphylococcal pore-forming toxins

    ‘Agents-in-focus’ and ‘Agents-in-context’: The strong structuration analysis of central government accounting practices and reforms in Nepal

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    Drawing on Stones’ (2005) strong structuration theory, the paper unfolds why and how the key stakeholders of central government accounting in Nepal are involved in the reproduction of routinised accounting practices, resisting the externally-propagated changes. Government accountants (the agents-in-focus) through their capability to control the budget routines have enjoyed a powerful social position in their position–practice relations with the agents-in-context, i.e. professional accountants and international consultants, higher-level officers and administrators, auditors, and politicians. Social position along with historically-imbued dispositions and their conduct and context analysis have enabled government accountants to strategically exercise their agency. Government accountants have articulated duality and a dialectic relation with the agents-in-context, which have resulted in the reproduction of everyday accounting practice and the resistance to the World Bank-led reforms, such as accrual accounting and, more recently, the Cash-Basis IPSAS

    Search for the Higgs boson in lepton, tau and jets final states

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    We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9.7 fb^{-1} of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H -> tau tau decays or H -> WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0 respectively

    Search for a Narrow ttbar Resonance in ppbar Collisions at sqrt{s}=1.96 TeV

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    We report a search for a narrow ttbar resonance that decays into a lepton+jets final state based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt{s}=1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to ttbar which we compare to predictions for a leptophobic topcolor Z' boson. We exclude such a resonance at the 95% confidence level for masses below 835 GeV.Comment: 7 pages, 3 figures, submitted to Physical Review Letter

    Precise measurement of the top quark mass in the dilepton channel at D0

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    We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure

    Implementing guidelines to routinely prevent chronic vascular disease in primary care: The Preventive Evidence into Practice cluster randomised controlled trial

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    Objective: To evaluate an intervention to improve implementation of guidelines for the prevention of chronic vascular disease. Setting: 32 urban general practices in 4 Australian states. Randomisation: Stratified randomisation of practices. Participants: 122 general practitioners (GPS) and practice nurses (PNs) were recruited at baseline and 97 continued to 12 months. 21 848 patient records were audited for those aged 40-69 years who attended the practice in the previous 12 months without heart disease, stroke, diabetes, chronic renal disease, cognitive impairment or severe mental illness. Intervention: The practice level intervention over 6 months included small group training of practice staff, feedback on audited performance, practice facilitation visits and provision of patient education and referral information. Outcome measures: Primary: 1. Change in proportion of patients aged 40-69 years with smoking status, alcohol intake, body mass index (BMI), waist circumference (WC), blood pressure (BP) recorded and for those aged 45-69 years with lipids, fasting blood glucose and cardiovascular risk in the medical record. 2. Change in the level of risk for each factor. Secondary: change in self-reported frequency and confidence of GPS and PNs in assessment. Results: Risk recording improved in the intervention but not the control group for WC (OR 2.52 (95% CI 1.30 to 4.91)), alcohol consumption (OR 2.19 (CI 1.04 to 4.64)), smoking status (OR 2.24 (1.17 to 4.29)) and cardiovascular risk (OR 1.50 (1.04 to 2.18)). There was no change in recording of BP, lipids, glucose or BMI and no significant change in the level of risk factors based on audit data. The confidence but not reported practices of GPS and PNs in the intervention group improved in the assessment of some risk factors. Conclusions: This intervention was associated with improved recording of some risk factors but no change in the level of risk at the follow-up audit. Trial registration number: Australian and New Zealand Clinical Trials Register (ANZCTR): ACTRN12612000578808, results
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