2,273 research outputs found

    Solar response of the BATSE instrument on the gamma-ray observatory

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    The Burst and Transient Source Experiment (BATSE) on board the gamma ray observatory (GRO) aims at comprehensive observations of time profiles, spectra, and locations of high-energy transient sources. The mysterious cosmic gamma ray bursts provided the main motivation for the observations, but BATSE will make excellent observations of many classes of sources, and in particular solar flares. The solar response of BATSE, as inferred from its design parameters, is analyzed for two purposes: the optimization of the solar observations themselves, and the characterization of the solar effects on ordinary nonsolar observations

    Field assessment of sediment trap efficiency under varying flow conditions

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    Knowledge of the collection efficiency of sediment traps, particularly under conditions of varying current speed, is presently more a matter of hope than confidence. We report here on a field experiment designed to determine, for a particular trap geometry, the effect of current speed and particle fall velocity on the collection efficiency of a moored trap relative to the presumably unbiased efficiency of an identical drifting trap. The experiment was performed in a deep estuarine tidal passage where a smoothly varying unidirectional flow and a spatially homogenous particle population mimicked laboratory flume conditions. A multiple-sample sediment trap integrated to a current meter partitioned the mass flux collected by the moored trap into one of four chambers according to the following speed intervals: \u3c12, 12–\u3c30, 30–\u3c50, and ≥50cm/s. The magnitude and particle characteristics of the flux collected at \u3c12 cm/s were indistinguishable from those simultaneously collected by drifting traps. At higher speeds, the relative efficiency of the moored trap ranged between 1% and 24% and the mean size and density of the trapped particles increased. These results support predictions based on laboratory studies that collection efficiency decreases with an increase in the trap Reynolds number or a decrease in particle fall velocity. The study demonstrates that consideration must be given to scaling both trap diameter and aspect ratio according to the expected flow conditions, and that knowledge of flow conditions at the trap mouth is necessary to properly interpret the flux data

    Little Yaller Boy / music by Gustave Kerker; words by Hugh Morton

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    Cover: Musical Supplement of the New York Journal and Advertiser. April 3, 1898; Publisher: T. B. Harms and Co. (New York)https://egrove.olemiss.edu/sharris_a/1040/thumbnail.jp

    Laparoscopic adjustable gastric banding – should a second chance be given?

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    Background: Obesity is a chronic relapsing-remitting disease and a global pandemic, being associated with multiple comorbidities. Laparoscopic adjustable gastric banding (LAGB) is one of the safest surgical procedures used for the treatment of obesity, and even though its popularity has been decreasing over time, it still remains an option for a certain group of patients, producing considerable weight loss and improvement in obesity-associated comorbidities. Methods: The aim of this study was to evaluate the impact of weight loss following LAGB on obesity-associated comorbidities, and to identify factors that could predict better response to surgery, and patient sub-groups exhibiting greatest benefit. A total of 99 severely obese patients (81.2% women, mean age 44.19 ± 10.94 years, mean body mass index (BMI) 51.84 ± 8.77 kg/m2) underwent LAGB in a single institution. Results obtained 1, 2, and 5 years postoperatively were compared with the pre-operative values using SPPS software version 20. Results: A significant drop in BMI was recorded throughout the follow-up period, as well as in A1c and triglycerides, with greatest improvement seen 2 years after surgery (51.8 ± 8.7 kg/m2 vs 42.3 ± 9.2 kg/m2, p < 0.05, 55.5 ± 19.1 mmol/mol vs 45.8 ± 13.7 mmol/mol, p < 0.05, and 2.2 ± 1.7 mmol/l vs 1.5 ± 0.6 mmol/l). Better outcomes were seen in younger patients, with lower duration of diabetes before surgery, and lower pre-operative systolic blood pressure. Conclusions: Younger age, lower degree of obesity, and lower severity of comorbidities at the time of surgery can be important predictors of successful weight loss, making this group of patients the ideal candidates for LAGB

    Direct evidence of lack of colocalisation of fluorescently labelled gold labels used in correlative light electron microscopy

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    Fluorescently labelled nanoparticles are routinely used in Correlative Light Electron Microscopy (CLEM) to combine the capabilities of two separate microscope platforms: fluorescent light microscopy (LM) and electron microscopy (EM). The inherent assumption is that the fluorescent label observed under LM colocalises well with the electron dense nanoparticle observed in EM. Herein we show, by combining single molecule fluorescent imaging with optical detection of the scattering from single gold nanoparticles, that for a commercially produced sample of 10 nm gold nanoparticles tagged to Alexa-633 there is in fact no colocalisation between the fluorescent signatures of Alexa-633 and the scattering associated with the gold nanoparticle. This shows that the attached gold nanoparticle quenches the fluorescent signal by ~95%, or less likely that the complex has dissociated. In either scenario, the observed fluorescent signal in fact arises from a large population of untagged fluorophores; rendering these labels potentially ineffective and misleading to the field

    The Role of the Private Sector in Supporting Malaria Control in Resource Development Settings.

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    Industrial operations of the private sector, such as extraction, agriculture, and construction, can bring large numbers of people into new settlement areas and cause environmental change that promotes the transmission of vector-borne diseases. Industry-related workers and communities unduly exposed to infection risk typically lack the knowledge and means to protect themselves. However, there is a strong business rationale for protecting local resident employees through integrated vector control programs, as well as an ethical responsibility to care for these individuals and the affected communities. We discuss the role and challenges of the private sector in developing malaria control programs, which can include extensive collaborations with the public sector that go on to form the basis of national vector control programs or more broadly support local healthcare systems

    Frequency-dependent time delays for strong outbursts in selected blazars from the MetsÄhovi and UMRAO monitoring data bases – II

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    We analyse the radio light curves of the blazars 1308+326, 2223−052 and 2251+158 using University of Michigan Radio Observatory and MetsÄhovi Radio Observatory multifrequency monitoring data combined with high-resolution very long baseline interferometry (VLBI) observations in order to extract the properties of prominent outbursts. The outbursts are classified as ‘core’ and ‘jet’ events according to their behaviour at different frequencies and their associations with features appearing in the VLBI jet. We define the activity cycle for each blazar as the time interval between successive ‘core’ outbursts. The durations of the activity cycle derived in this way are ≥14 yr for 1308+326, ∼12 yr for 2223−052 and 12.4 ± 0.6 yr for 2251+158. We find an unusual frequency dependence for the time profiles for a major flare in 1308+326, which may provide evidence for acceleration or bending of the jet flow in the optically thick part of the emission region. Analysis of these activity cycles, combined with our earlier results, leads us to suggest that more luminous blazars possess shorter activity cycles, consistent with the accretion rates being higher in more powerful sources (relative to the Eddington rate).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72279/1/j.1365-2966.2007.12281.x.pd

    Water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in the Great Lakes: Playing with fire?

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    The Laurentian Great Lakes have been successfully invaded by at least 182 nonindigenous species. Here we report on two new species, water hyacinth Eichhornia crassipes and water lettuce Pistia stratiotes, that were found at a number of locations in Lake St. Clair and Detroit River during autumn 2010. Both species are commonly sold in the water garden and aquarium trade in southern Ontario and elsewhere. While it is not clear whether these species are established or can establish in the Great Lakes, the historic assumption that neither of these subtropical to tropical plants pose an invasion risk must be questioned in the light of changing environmental conditions associated with climate warming that may render Great Lakes\u27 habitats more suitable for these species and increase the likelihood of their successful establishment. © 2011 The Author(s)

    Optoelectronics with electrically tunable PN diodes in a monolayer dichalcogenide

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    One of the most fundamental devices for electronics and optoelectronics is the PN junction, which provides the functional element of diodes, bipolar transistors, photodetectors, LEDs, and solar cells, among many other devices. In conventional PN junctions, the adjacent p- and n-type regions of a semiconductor are formed by chemical doping. Materials with ambipolar conductance, however, allow for PN junctions to be configured and modified by electrostatic gating. This electrical control enables a single device to have multiple functionalities. Here we report ambipolar monolayer WSe2 devices in which two local gates are used to define a PN junction exclusively within the sheet of WSe2. With these electrically tunable PN junctions, we demonstrate both PN and NP diodes with ideality factors better than 2. Under excitation with light, the diodes show photodetection responsivity of 210 mA/W and photovoltaic power generation with a peak external quantum efficiency of 0.2%, promising numbers for a nearly transparent monolayer sheet in a lateral device geometry. Finally, we demonstrate a light-emitting diode based on monolayer WSe2. These devices provide a fundamental building block for ubiquitous, ultra-thin, flexible, and nearly transparent optoelectronic and electronic applications based on ambipolar dichalcogenide materials.Comment: 14 pages, 4 figure

    Sheep Updates 2007 - part 5

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    This session covers six papers from different authors: GENETIC IMPROVEMENT 1. Breech Strike Resistance: Selecting for resistance traits reduces breech strike, Bindi Murray, John Karlsson, Johan Greeff, Department of Agriculture and Food, Western Australia 2. Breeding Merino Sheep for Worm Resistance increases profit in a Mediterranean Environment, John Karlsson and Johan Greeff Department of Agriculture and Food, Western Australia FEEDING 3. Embryo lasses were not increased when Merino ewes that had lost weight were supplemented with lupins, C. Viñoles Gil, B.L. Paganoni, K.M.M. Glover, J.T.B. Milton & G.B. Martin, School of Animal Biology, Faculty of Natural and Agricultural Sciences, University of Western Australia, Crawley, WA 4. Mineral nutrition of sheep grazing dual-purpose wheats, Hugh Dove, CSIRO Plant Industry, Canberra, ACT BEEF PRODUCTIVITY 5. The effect of genetic potential and pre feedlot growth path on beef eating quality, Bill McKiernan and John WilkinsNSW Department of Primary Industries 6. Long-term consequences of growth and nutrition of cattle early in life for beef production, Paul Greenwood and Linda Cafe, Cooperative Research Centre for Beef Genetic Technologies, and NSW Department of Primary Industries Beef Industry Centre of Excellence, University of New England, Armidale NS
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