640 research outputs found

    Delineating shallow ground water irrigated areas in the Atankwidi Watershed (Northern Ghana, Burkina Faso) using Quickbird 0.61 - 2.44 meter data

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    The major goal of this research was to delineate the shallow groundwater irrigated areas (SGI) in the Atankwidi Watershed in the Volta River Basin of West Africa. Shallow ground water irrigation is carried out using very small dug-wells all along the river banks or shallow dug-outs all along the river bed. Each of these dug-wells and dug-outs are highly fragmented small water bodies that irrigate only a fraction of an acre. However, these are contiguous dug-wells and dug-outs that are hundreds or thousands in number. Very high spatial resolution (VHSR) Quickbird imagery (0.61 to 2.44 m) was used to identify: (a) dug-wells that hold small quantities of water in otherwise dry stream; and (b) dug-outs that are just a meter or two in depth but have dug-out soils that are dumped just next to each well. The Quickbird VHSR imagery was found ideal to detect numerous: (i) dug-wells through bright soils that lay next to each dug-well, and (ii) water bodies all along the dry stream bed. We used fusion of 0.61 m Quickbird panchromatic data with 2.44 Quickbird multispectral data to highlight SGI and delineate their boundaries. Once this was achieved, classification techniques using Quickbird imagery was used within the delineated areas to map SGI and other land use/land cover (LULC) areas. Results obtained showed that SGI is practiced on a land area of 387 ha (1.4%), rainfed areas is 15638 ha (54.7%) and the remaining area in other LULC. These results were verified using field-plot data which showed an accuracy of 92% with errors of omissions and commissions less than 10%.Key words: Shallow groundwater, Quickbird, remote sensing, irrigated areas, Atankwidi Watershed, Ghana

    Real-time Processor-in-Loop investigation of a modified non-linear state observer using sliding modes for speed sensorless induction motor drive in electric vehicles

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    Tracking performance and stability play a major role in observer design for speed estimation purpose in motor drives used in vehicles. It is all the more prevalent at lower speed ranges. There was a need to have a tradeoff between these parameters ensuring the speed bandwidth remains as wide as possible. This work demonstrates an improved static and dynamic performance of a sliding mode state observer used for speed sensorless 3 phase induction motor drive employed in electric vehicles (EVs). The estimated torque is treated as a model disturbance and integrated into the state observer while the error is constrained in the sliding hyperplane. Two state observers with different disturbance handling mechanisms have been designed. Depending on, how they reject disturbances, based on their structure, their performance is studied and analyzed with respect to speed bandwidth, tracking and disturbance handling capability. The proposed observer with superior disturbance handling capabilities is able to provide a wider speed range, which is a main issue in EV. Here, a new dimension of model based design strategy is employed namely the Processor-in-Loop. The concept is validated in a real-time model based design test bench powered by RT-lab. The plant and the controller are built in a Simulink environment and made compatible with real-time blocksets and the system is executed in real-time targets OP4500/OP5600 (Opal-RT). Additionally, the Processor-in-Loop hardware verification is performed by using two adapters, which are used to loop-back analog and digital input and outputs. It is done to include a real-world signal routing between the plant and the controller thereby, ensuring a real-time interaction between the plant and the controller. Results validated portray better disturbance handling, steady state and a dynamic tracking profile, higher speed bandwidth and lesser torque pulsations compared to the conventional observer

    Blame, Symbolic Stigma and HIV Misconceptions are Associated with Support for Coercive Measures in Urban India

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    This study was designed to examine the prevalence of stigma and its underlying factors in two large Indian cities. Cross-sectional interview data were collected from 1,076 non-HIV patients in multiple healthcare settings in Mumbai and Bengaluru, India. The vast majority of participants supported mandatory testing for marginalized groups and coercive family policies for PLHA, stating that they “deserved” their infections and “didn’t care” about infecting others. Most participants did not want to be treated at the same clinic or use the same utensils as PLHA and transmission misconceptions were common. Multiple linear regression showed that blame, transmission misconceptions, symbolic stigma and negative feelings toward PLHA were significantly associated with both stigma and discrimination. The results indicate an urgent need for continued stigma reduction efforts to reduce the suffering of PLHA and barriers to prevention and treatment. Given the high levels of blame and endorsement of coercive policies, it is crucial that such programs are shaped within a human rights framework

    Usage of Glimepiride/Metformin Fixed-dose Combination in Young Individuals with Type 2 Diabetes: The Indian Experience

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    Background: The prevalence of diabetes has been rising among the younger population and is a cause for concern. The present case-based questionnaire survey evaluated the treatment pattern and clinical experience of healthcare professionals (HCPs) in prescribing glimepiride/metformin fixed-dose combination (FDC) to young diabetes patients (up to 40 years of age) in the Indian setting. Material and methods: A retrospective, multicenter, observational, questionnaire-based survey was conducted in Indian healthcare centers using medical records of patients having type 2 diabetes mellitus (T2DM), who were prescribed different strengths of glimepiride/metformin FDCs. Data was collected from the patients’ medical records and were analyzed using statistical tests. Results: A total of 2,715 patients aged between 18 and 40 years were included in the study. Mean diabetes duration among the young patients was 2.76 ± 1.97 years. Among the young T2DM patients, 83.2% patients received glimepiride/metformin FDC as first-line therapy, and 16.8% received it as second-line therapy. Hypoglycemia at 6 months was noted in only 2.47% of the young patients. Mean glycated hemoglobin (HbA1c) before and after treatment was 8.7% ± 3.4% and 7.3% ± 3.9%, respectively. Mean fasting plasma glucose (FPG) was 171.8 ± 80.1 mg/dL in patients prior to treatment initiation and came down to 122.8 ± 41.8 mg/dL after treatment with glimepiride/metformin FDC. Mean postprandial plasma glucose (PPG) prior to combination therapy use was 248.7 ± 64.0 mg/dL and dropped to 177.2 ± 39.9 mg/dL after treatment. Good to excellent efficacy and tolerability were reported for 86% and 86.6% patients, respectively. Conclusion: This case-based questionnaire survey demonstrates the usage pattern of various strengths of glimepiride/metformin FDCs and the HCPs’ practice approach regarding the use of this combination in young T2DM patients in the Indian setting. The combination is commonly prescribed to young diabetes patients in India and is associated with beneficial effects on glycemic parameters

    An optimized TOPS+ comparison method for enhanced TOPS models

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    This article has been made available through the Brunel Open Access Publishing Fund.Background Although methods based on highly abstract descriptions of protein structures, such as VAST and TOPS, can perform very fast protein structure comparison, the results can lack a high degree of biological significance. Previously we have discussed the basic mechanisms of our novel method for structure comparison based on our TOPS+ model (Topological descriptions of Protein Structures Enhanced with Ligand Information). In this paper we show how these results can be significantly improved using parameter optimization, and we call the resulting optimised TOPS+ method as advanced TOPS+ comparison method i.e. advTOPS+. Results We have developed a TOPS+ string model as an improvement to the TOPS [1-3] graph model by considering loops as secondary structure elements (SSEs) in addition to helices and strands, representing ligands as first class objects, and describing interactions between SSEs, and SSEs and ligands, by incoming and outgoing arcs, annotating SSEs with the interaction direction and type. Benchmarking results of an all-against-all pairwise comparison using a large dataset of 2,620 non-redundant structures from the PDB40 dataset [4] demonstrate the biological significance, in terms of SCOP classification at the superfamily level, of our TOPS+ comparison method. Conclusions Our advanced TOPS+ comparison shows better performance on the PDB40 dataset [4] compared to our basic TOPS+ method, giving 90 percent accuracy for SCOP alpha+beta; a 6 percent increase in accuracy compared to the TOPS and basic TOPS+ methods. It also outperforms the TOPS, basic TOPS+ and SSAP comparison methods on the Chew-Kedem dataset [5], achieving 98 percent accuracy. Software Availability: The TOPS+ comparison server is available at http://balabio.dcs.gla.ac.uk/mallika/WebTOPS/.This article is available through the Brunel Open Access Publishing Fun

    Comprehensive characterization of molecular interactions based on nanomechanics

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    Molecular interaction is a key concept in our understanding of the biological mechanisms of life. Two physical properties change when one molecular partner binds to another. Firstly, the masses combine and secondly, the structure of at least one binding partner is altered, mechanically transducing the binding into subsequent biological reactions. Here we present a nanomechanical micro-array technique for bio-medical research, which not only monitors the binding of effector molecules to their target but also the subsequent effect on a biological system in vitro. This label-free and real-time method directly and simultaneously tracks mass and nanomechanical changes at the sensor interface using micro-cantilever technology. To prove the concept we measured lipid vesicle (approximately 748*10(6) Da) adsorption on the sensor interface followed by subsequent binding of the bee venom peptide melittin (2840 Da) to the vesicles. The results show the high dynamic range of the instrument and that measuring the mass and structural changes simultaneously allow a comprehensive discussion of molecular interactions

    Rationality, Irrationality and Escalating Behavior in Lowest Unique Bid Auctions

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    Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions – lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of “bid space”. The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets

    Understanding the socio-economic impacts of climate change on riparian communities in Bangladesh

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    Riparian communities in developing countries such as Bangladesh, whose livelihoods depend especially on fisheries and other subsistence activities, are under considerable pressure due to climate change. Therefore, there is a need to better understand how the dynamics of riparian communities are influenced by climate change and how its impacts can be assessed. Using Bangladesh as an example, this paper describes the various climate stressors affecting riparian communities and their socio-economic impacts, and it outlines some measures needed to increase their resilience to a changing climate. The results show that riparian communities are not only quite vulnerable to the impacts of climate change but also have a rather low level of resilience. This challenge can, at least in part, be attributed to their fragile living conditions, which intensify the socio-economic impacts of extreme events. One lesson from the paper is that handling climate-induced risks in riparian communities requires implementing strategic measures to improve local climate and livelihood resilience, such as effective public health infrastructure and a resilient built environment. Win-win scenarios comprise strategies that offer multiple benefits including better water storage, flood control, and improved riparian habitats

    Parameter induction in continuous univariate distributions: Well-established G families

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    Diverging Mechanisms of Activation of Chemokine Receptors Revealed by Novel Chemokine Agonists

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    CXCL8/interleukin-8 is a pro-inflammatory chemokine that triggers pleiotropic responses, including inflammation, angiogenesis, wound healing and tumorigenesis. We engineered the first selective CXCR1 agonists on the basis of residue substitutions in the conserved ELR triad and CXC motif of CXCL8. Our data reveal that the molecular mechanisms of activation of CXCR1 and CXCR2 are distinct: the N-loop of CXCL8 is the major determinant for CXCR1 activation, whereas the N-terminus of CXCL8 (ELR and CXC) is essential for CXCR2 activation. We also found that activation of CXCR1 cross-desensitized CXCR2 responses in human neutrophils co-expressing both receptors, indicating that these novel CXCR1 agonists represent a new class of anti-inflammatory agents. Further, these selective CXCR1 agonists will aid at elucidating the functional significance of CXCR1 in vivo under pathophysiological conditions
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