347 research outputs found

    The Evolution of Dispersal Conditioned on Migration Status

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    We build on the work of El Mouden and Gardner (2008) and consider the evolution of natal dispersal conditioned upon an individual’s ‘migration status’. In particular, we look to compare the evolution of this kind of conditional dispersal with the evolution of its un­ conditional counterpart. Our goal is to determine the extent to which dispersal conditional upon migration status changes predictions about population-wide levels of dispersal. Sim­ ply we ask: what weight should the possibility of this kind of conditional dispersal be given by an evolutionary biologist? We find the stable dispersal rates of natives and non­ natives, respectively, are predicted to vary with changing parameter values, and the stable dispersal rates of natives and non-natives are predicted to differ from one another in a way consistent with inclusive-fitness theory. We also find differencs between Taylor’s (1988) unconditional dispersal rate, and the population-average dispersal rate predicted by our model

    Comparative performance of two extractants in colorimetric determination of soil organic matter in paddy soil

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    Commonly used soil organic carbon (SOC) determination methods are expensive, time consuming, require equipment and skilled personnel making them impractical to use at field level. Therefore, a laboratory analytical study was carried out to identify a suitable extractant for SOC extraction as part of an ongoing effort to develop a low cost quick method for determining soil organic matter (SOM) at field level. For this purpose, 38 soil samples were collected from different Agro Ecological Zone (AEZ) to represent typical rice based cropping pattern covering a sufficient range in texture, soil organic matter, pH, and type of management. Two extractants e.g. NaOH-Pyrophosphate + HCl and NaOH-EDTA were used to extract organic carbon from soil and two wavelength e.g. 300 and 400 nm were used to measure the absorbance of organic carbon in spectrophotometer. Soil organic carbon measurements by CNS analyzer were used as reference measurement to compare the extracting efficiency of SOC by the selected extractants. Both the extract and wavelength showed different degrees of error in OC measurement. The error sum square of NaOH-Pyrophosphate + HCl and NaOH-EDTA measured at 300 nm wavelength were 15.21 and 13.35 whereas at 400 nm it was 227.37 and 19.95, respectively. Consequently, the average error percentages at 300 nm were -33 and -8 while at 400 nm it was - 187 and -16. Based on the error sum square and error percentage, NaOH-Pyrophosphate + HCl performed better than the NaOH-EDTA, and 400 nm wavelength came out better than the 300 nm wavelength. In addition, both the extracts produced coloured solutions which were easily visible or detectable by naked eye and the colour intensity increased with the increase in SOC content. Variations in colour among the soils depending on organic matter content indicate that it would be possible to develop a new low cost method for SOM determination at field level by using NaOH-Pyrophosphate + HCl as the extractant. Further research is warranted to confirm this finding

    Parametric analyses of summative scores may lead to conflicting inferences when comparing groups: a simulation study

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    Objective: To investigate whether using a parametric statistic in comparing groups leads to different conclusions when using summative scores from rating scales compared with using their corresponding Rasch-based measures

    Size-dependent permittivity and intrinsic optical anisotropy of nanometric gold thin films: A density functional theory study

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    Physical properties of materials are known to be different from the bulk at the nanometer scale. In this context, the dependence of optical properties of nanometric gold thin films with respect to film thickness is studied using density functional theory (DFT). We find that the in-plane plasma frequency of the gold thin film decreases with decreasing thickness and that the optical permittivity tensor is highly anisotropic as well as thickness dependent. Quantitative knowledge of planar metal film permittivity's thickness dependence can improve the accuracy and reliability of the designs of plasmonic devices and electromagnetic metamaterials. The strong anisotropy observed may become an alternative method of realizing indefinite media. © 2013 Optical Society of America

    An exploratory study to examine abundance of PM2.5 and associated disease burden in Bangladesh

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    This study examined selected disease burdens in Bangladesh associated with particulate matter exposure using gridded population and PM2.5 data between 2001 and 2019. The Global Exposure Mortality Model (GEMM) was used to determine hazard ratio (HR) and disease specific mortality. Besides, trend of PM2.5 and selected diseases were evaluated. Results revealed that strong seasonality existed in PM2.5 with winter exhibited maximum concentration. The trend assessment showed PM2.5 was increasing over time. Among five diseases assessed, LRI was most sensitive to an increase of PM2.5, followed by IHD, LC, CEV and COPD. Excess mortality was found to be elevating because of PM2.5, particularly in major cities. This study could be useful in advancing research in the disease burden attributable to ambient air pollution in Bangladesh

    Towards effective capacity planning in a perinatal network centre

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    Objective To study the arrival pattern and length of stay (LoS) in a neonatal intensive care/high dependency unit (NICU/HDU) and special care baby unit (SCBU) and the impact of capacity shortage in a perinatal network centre, and to provide an analytical model for improving capacity planning. Methods The data used in this study have been collected through the South England Neonatal Database (SEND) and the North Central London Perinatal Network Transfer Audit between 1 January and 31 December 2006 for neonates admitted and refused from the neonatal unit at University College London Hospital (UCLH). Exploratory data analysis was performed. A queuing model is proposed for capacity planning of a perinatal network centre. Outcome measures Predicted number of cots required with existing arrival and discharge patterns; impact of reducing LoS. Results In 2006, 1002 neonates were admitted to the neonatal unit at UCLH, 144 neonates were refused admission to the NICU and 35 to the SCBU. The model shows the NICU requires seven more cots to accept 90% of neonates into the NICU. The model also shows admission acceptance can be increased by 8% if LoS can be reduced by 2 days. Conclusions The arrival, LoS and discharge of neonates having gestational ages of <27 weeks were the key determinants of capacity. The queuing model can be used to determine the cot capacity required for a given tolerance level of admission rejection

    Correction to: Tumour suppressor EP300, a modulator of paclitaxel resistance and stemness, is downregulated in metaplastic breast cancer

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    In the original publication, Fig. 1 depicting the blot for EP300 in CAL51 cells (Fig. 1c) was unintentionally duplicated with that from MDA-MB-231 cells (Fig. 1d). The new figure given in this erratum depicts the correct EP300 blot in Fig. 1c

    Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

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    The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

    Design and Development of a Single Channel Analyzer with Microcontroller Based Controlled Output

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    Single Channel Analyzer (SCA) is a most common device used in today\u27s nuclear world. Therefore, A SCA with microcontroller based controlled output has been proposed in this article. The system comprises of Lower Level Discriminator (LLD), Upper Level Discriminator (ULD), wide dynamic range, Fast Processing and Hysteresis. The Comparator LM339N used as the key component that performs the main function of the proposed nuclear module. The multi-turn potentiometers have been used as LLD and ULD for the incoming linear pulses from shaping amplifier. The system has also employ the Hysteresis facilities so that oscillations due to stray feedback are not possible. A lower pin and less housing PIC microcontroller (P16F676) has been used to control the width and time delay of the output pulses

    Gender Inequality in Bangladesh

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    This study focused on gender inequality and its impact on socio-economic development of rural households in Bangladesh. To know the main reasons and areas of gender inequality and its impact on household development the study was carried out in five villages of Sadar Upazilla of Mymensingh District. Data were collected from a purposively drawn sample of 85 from 900 rural households. The study indicated that disparity exists in targeted area, which on many grounds affects the development of rural households. Findings indicated that women had no or low share in income/ earnings of the family, that there was no equal status of women, female were not allowed to work outside home, women were more vulnerable to poverty, women share more burden of productive and household work. The women’s participation rate was higher in cleaning house, child care, cooking and preparation of meal and lowest in case of tree plantation, dairy farming, poultry rearing etc. About 88 per cent women contributed to increase their family income. Male members dominated in household decision, there was no equal opportunity in higher education, physical and mental health for women, and women were facing difficulties in labor market. The participation rate of women in many decisions making process such as marriage, education of sons and daughters, buying health care facilities, use of contraceptive and participating NGOs were very low. Gender inequality increases maternal mortality (92 per cent agree), increase fertility (88 per cent agree), increase dowry (88 per cent agree) and domestic violence (89 per cent agree). Social norms and values restricted women to participate in development activities
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