612 research outputs found
Studies on spatial pattern of NDVI over Indiaand its relationship with rainfall, air temperature, soil moisture adequacy and ENSO
The changes in spatial distribution of Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) are studied for different seasons in India for the period 1982 to 2000. The inter-annual variability of All India NDVI (AINDVI) has been studied and related to rainfall, air temperature, soil moisture adequacy, Southern Oscillation Index (SOI) and Nino 3 Sea Surface Temperature (Nino 3 SST) to understand the influence of these variables on vegetal cover. The results show that the NDVI is high during the south-west (June to September) monsoon and retreat (October and November) seasons where in major crop seasons Kharif and Rabi take place over India. The trend of AINDVI is increasing and displayed higher values during La Niña and lower in El Niño episodes. The correlation between rainfall and NDVI of All India is not significant on monthly basis (+0.13) but it is more prominent when the cumulative annual amounts of rainfall are involved (+0.61). NDVI responded very well to the variations of soil moisture adequacy (SAD) which enumerates the strongest correlation (+0.73) of crop performance with NDVI. This significant strong correlation inferred that SAD can be taken as the indicator for the NDVI variations rather rainfall. The linear regression analysis of AINDVI and the ENSO indices revealed the strong impact of sea surface temperatures than SOI on vegetation pattern over India
Studies on spatial pattern of NDVI over india and its relationship with rainfall, air temperature, soil moisture adequacy and ENSO
The changes in spatial distribution of Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) are studied for different seasons in India for the period 1982 to 2000. The inter-annual variability of All India NDVI (AINDVI) has been studied and related to rainfall, air temperature, soil moisture adequacy, Southern Oscillation Index (SOI) and Nino 3 Sea Surface Temperature (Nino 3 SST) to understand the influence of these variables on vegetal cover. The results show that the NDVI is high during the south-west (June to September) monsoon and retreat (October and November) seasons where in major crop seasons Kharif and Rabi take place over India. The trend of AINDVI is increasing and displayed higher values during La Niña and lower in El Niño episodes. The correlation between rainfall and NDVI of All India is not significant on monthly basis (+0.13) but it is more prominent when the cumulative annual amounts of rainfall are involved (+0.61). NDVI responded very well to the variations of soil moisture adequacy (SAD) which enumerates the strongest correlation (+0.73) of crop performance with NDVI. This significant strong correlation inferred that SAD can be taken as the indicator for the NDVI variations rather rainfall. The linear regression analysis of AINDVI and the ENSO indices revealed the strong impact of sea surface temperatures than SOI on vegetation pattern over India
Hummingbird: An Energy-Efficient GPS Receiver for Small Satellites
Global positioning system (GPS) is the most widely adopted localization technique for satellites in low earth orbits (LEOs). To enable many state-of-the-art applications on satellites, the exact position of the satellites is necessary. With the increasing demand for small satellites, the need for a low-power GPS for satellites is also increasing. However, building low-power GPS receivers for small satellites poses significant challenges, mainly due to the high speeds (similar to 7.8 km/s) of satellites and low available energy. While duty cycling the receiver is a possible solution, the high relative Doppler shift among the GPS satellites and the small satellite contributes to an increase in Time to First Fix (TTFF), which negatively impacts energy consumption. Further, if the satellite tumbles, the GPS receiver may not be able to receive signals properly from the GPS satellites, thus leading to an even longer TTFF. In the worst case, the situation may result in no GPS fix due to disorientation of the receiver antenna. In this work, we elucidate the design of a low-cost, low-power GPS receiver for small satellites. We also propose an energy optimization algorithm to improve the TTFF. With the extensive evaluation of our GPS receiver on an operational nanosatellite, we show that up to 96.16% of energy savings can be achieved using our algorithm without significantly compromising (similar to 10 m) the positioning accuracy
Predicting the risk of end-stage renal disease in the population-based setting: a retrospective case-control study
Development and evaluation of a hand held computer based on-call pack for health protection out of hours duty: A pilot study
BACKGROUND: The on call service for health protection in most parts of the UK is provided by general public health consultants, registrars and nurses as the first tier of response backed up by medical consultants in health protection. The first tier responder usually carries a large bag of papers containing both local and national guidance on the management of common cases/incidents. An electronic on call pack may provide a suitable practical alternative to large paper based systems and help professionals deliver out of hours health protection advice and response to incidents. METHODS: We developed and piloted an electronic on call pack in Hertfordshire for use at the health protection unit level containing key local and national guidelines, contact information and useful references. The on-call pack was initially piloted using a laptop and more recently using a personal digital assistant (PDA). The use of the on-call pack was evaluated. RESULTS: Key advantages of the electronic system include reduced size, faster access to information that is clearly indexed and the relative ease of updating information. As part of the pilot, the electronic on call pack was presented to a local and regional training meeting with good response from participants using qualitative and quantitative methods. CONCLUSION: It is anticipated that with suitable evaluation this system can be adapted and utilised by other health protection practitioners. This system provides a fast, reliable and easily maintained source of information for the public health on-call team
Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector
This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}4.6\;{\rm f}{{{\rm b}}^{-1}}{{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}|\eta |\lt 1.9{{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques
Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at root s=7 TeV with the ATLAS detector
A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb-1 to 4.8 fb-1. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, φ, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters mA and tan β in the mhmax scenario for mA in the range of 90GeV to 500 GeV. Copyright CERN
Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at √s=8TeV
The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fb−1of data collected in proton–proton collisions at √s=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV
Genetic polymorphisms located in genes related to immune and inflammatory processes are associated with end-stage renal disease: a preliminary study
Background
Chronic kidney disease progression has been linked to pro-inflammatory cytokines and markers of inflammation. These markers are also elevated in end-stage renal disease (ESRD), which constitutes a serious public health problem.
Objective
To investigate whether single nucleotide polymorphisms (SNPs) located in genes related to immune and inflammatory processes, could be associated with ESRD development.
Design and methods
A retrospective case-control study was carried out on 276 patients with ESRD and 288 control subjects. Forty-eight SNPs were genotyped via SNPlex platform. Logistic regression was used to assess the relationship between each sigle polymorphism and the development of ESRD.
Results
Four polymorphisms showed association with ESRD: rs1801275 in the interleukin 4 receptor (IL4R) gene (OR: 0.66 (95%CI=0.46-0.95); p=0.025; overdominant model), rs4586 in chemokine (C-C motif) ligand 2 (CCL2) gene (OR: 0.70 (95%CI=0.54-0.90); p=0.005; additive model), rs301640 located in an intergenic binding site for signal transducer and activator of transcription 4 (STAT4) (OR: 1.82 (95%CI=1.17-2.83); p=0.006; additive model) and rs7830 in the nitric oxide synthase 3 (NOS3) gene (OR: 1.31 (95%CI=1.01-1.71); p=0.043; additive model). After adjusting for multiple testing, results lost significance.
Conclusion
Our preliminary data suggest that four genetic polymorphisms located in genes related to inflammation and immune processes could help to predict the risk of developing ESRD.This work was supported by grants from Instituto de Salud Carlos III (Ref: PI08/0738 and PI11/00245) to SR and Junta de Castilla y Leon (Ref: GRS 234/A/08) to ET. MAJS is supported by a grant from Instituto de Salud Carlos III (CM10/00105).Jimenez-Sousa, MA.; López, E.; Fernandez-Rodriguez, A.; Tamayo, E.; Fernández-Navarro, P.; Segura Roda, L.; Heredia, M.... (2012). Genetic polymorphisms located in genes related to immune and inflammatory processes are associated with end-stage renal disease: a preliminary study. BMC Medical Genetics. 13(58):1-6. https://doi.org/10.1186/1471-2350-13-58S161358Otero A, de Francisco A, Gayoso P, Garcia F: Prevalence of chronic renal disease in Spain: results of the EPIRCE study. Nefrologia. 2010, 30 (1): 78-86.Kottgen A: Genome-wide association studies in nephrology research. 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