4,018 research outputs found
Estimating Aquifer System Storage Loss with Water Levels, Pumping and InSAR Data in the Parowan Valley, Utah
In the Parowan Valley of Utah, Groundwater Levels Have Declined by as Much as 30 M over the Past 50 Years with Accompanying Subsidence Rates of Up to 5 Cm/year. Traditional Methods to Estimate Groundwater Storage Change Use a Combination of Groundwater Level and Storativity Estimates, But There is Often Considerable Uncertainty in These. in This Study, We Demonstrate a New Method that Relies on a Combination of Geodetic Data from InSAR, as Well as Groundwater Level and Pumping Data, to Estimate Both the Total Groundwater Storage Loss and the Percentages of Storage Loss in Fine- and Coarse-Grained Layers within an Aquifer System. We Find that When Aggregated over All of Parowan Valley, Fine- and Coarse-Grained Layers Account for Roughly Equal Portions of the Total Groundwater Storage Loss. However, in Confined Aquifers, Fine-Grained Layers Account for Most of the Storage Loss. This Has Important Implications on the Source of Groundwater in Depleting Aquifer Systems, as Many Models Do Not Account for Fine-Grained Layers as a Source of Water. We Find that in the Parowan Valley, the Aquifer Depletion is Roughly 12.5% of the Volume of Pumped Groundwater, Meaning that the Remainder of Pumped Groundwater is Sourced from Net Inflow. This Study Presents the First Method that Combines Geodetic and in Situ Groundwater Data to Provide Estimates of Groundwater Storage Change that Account for Both Coarse- and Fine-Grained Intervals, Which Are Typically Present in Significant Amounts in the Major Unconsolidated Aquifer Systems of the World
The functions of repressor element 1-silencing transcription factor in models of epileptogenesis and post-ischemia
Epilepsy is a debilitating neurological disorder characterised by recurrent seizures for which 30% of patients are refractory to current treatments. The genetic and molecular aetiologies behind epilepsy are under investigation with the goal of developing new epilepsy medications. The transcriptional repressor REST (Repressor Element 1-Silencing Transcription factor) is a focus of interest as it is consistently upregulated in epilepsy patients and following brain insult in animal models of epilepsy and ischemia. This review analyses data from different epilepsy models and discusses the contribution of REST to epileptogenesis. We propose that in healthy brains REST acts in a protective manner to homeostatically downregulate increases in excitability, to protect against seizure through downregulation of BDNF (Brain-Derived Neurotrophic Factor) and its receptor, TrkB (Tropomyosin receptor kinase B). However, in epilepsy patients and post-seizure, REST may increase to a larger degree, which allows downregulation of the glutamate receptor subunit GluR2. This leads to AMPA glutamate receptors lacking GluR2 subunits, which have increased permeability to Ca2+, causing excitotoxicity, cell death and seizure. This concept highlights therapeutic potential of REST modulation through gene therapy in epilepsy patients
Large-area submillimeter resolution CdZnTe strip detector for astronomy
We report the first performance measurements of a sub-millimeter CdZnTe strip detector developed as a prototype for space-borne astronomical instruments. Strip detector arrays can be used to provide two-dimensional position resolution with fewer electronic channels than pixellated arrays. Arrays of this type and other candidate technologies are under investigation for the position-sensitive backplane detector for a coded-aperture telescope operating in the range of 30 - 300 keV. The prototype is a 1.4 mm thick, 64 multiplied by 64 stripe CdZnTe array of 0.375 mm pitch in both dimensions, approximately one square inch of sensitive area. Pulse height spectra in both single and orthogonal stripe coincidence mode were recorded at several energies. The results are compared to slab- and pixel-geometry detector spectra. The room-temperature energy resolution is less than 10 keV (FWHM) for 122 keV photons with a peak-to-valley ratio greater than 5:1. The response to photons with energies up to 662 keV appears to be considerably improved relative to that of previously reported slab and pixel detectors. We also show that strip detectors can yield spatial and energy resolutions similar to those of pixellated arrays with the same dimensions. Electrostatic effects on the pulse heights, read-out circuit complexity, and issues related to design of space borne instruments are also discussed
Physical profile of Air Force Special Warfare trainees
International Journal of Exercise Science 16(4): 924-931, 2023. Physical fitness testing in the military is commonly used to assess whether service members are physically capable of performing the diverse physical tasks that may be required for their job. Body composition can influence an individual’s ability to physically perform. This study aimed to analyze the general physical profile of U.S. Air Force (USAF) special warfare candidates by assessing body composition results and physical assessment scores collected over the past four years. Male candidates (n = 1036) were 18.2 years to 39.5 years of age (M = 23.5, SD = 3.9) and weighed 78.8 kg (SD = 8.3) with a BMI of 25.0 (SD = 2.0) at 11.8% body fat (SD = 3.3) as measured using bioelectrical impedance. Body composition and fitness scores were similar to those noted in U.S. Navy special warfare candidates as well as individuals in other elite tactical units. These results highlight the normative body composition profile of individuals assessing for advanced military career fields
A mouse model for chronic pain-induced increase in ethanol consumption
Chronic pain conditions are often co-morbid with alcohol abuse. “Self-medication” with alcohol introduces a host of problems associated with the abuse of alcohol which over time has the potential of exacerbating the painful condition. Despite the prevalence of chronic pain being associated with alcohol abuse, rodent models which mimic the co-morbid conditions are lacking. In the present study, we model osteoarthritis (OA) in C57BL/6J mice by surgically destabilizing the medial meniscus (DMM). Sham operated mice served as controls. Thirteen weeks after surgery, DMM but not sham operated mice exhibited pronounced incapacitance of the surgically-manipulated hindlimb compared to the non-surgically manipulated hindlimb. At this time, the mice were exposed to the two-bottle ethanol choice, beginning with 2.5% with a gradual increasing to 20%. Compared to sham controls, DMM mice consumed more EtOH and preferred EtOH over water at the 20% EtOH concentration. Histological analysis verified that the DMM mice exhibited significant damage to the articular cartilage and osteophyte growth compared to sham controls and these measures of the severity of OA correlated with the amount of ethanol intake. Thus, the combination of the DMM model of OA with the enhanced two-bottle ethanol choice is a potential preclinical approach in mice by which the basis of the co-morbid association of alcohol abuse and chronic pain conditions can be explored
Development of an orthogonal-stripe CdZnTe gamma radiation imaging spectrometer
We report performance measurements of a sub-millimeter resolution CdZnTe strip detector developed as a prototype for astronomical instruments operating with good efficiency in the 30-300 keV photon energy range. The prototype is a 1.4 mm thick, 64×64 contact stripe CdZnTe array of 0.375 mm pitch in both dimensions. Pulse height spectra were recorded in orthogonal-stripe coincidence mode which demonstrate room-temperature energy resolution \u3c10 keV (FWHM) for 122 keV photons with a peak-to-valley ratio \u3e5:1. Good response is also demonstrated at higher energies using a coplanar grid readout configuration. Spatial resolution capabilities finer than the stripe pitch are demonstrated. We present the image of a 133Ba source viewed through a collimator slit produced by a 4×4 stripe detector segment. Charge signals from electron and hole collecting contacts are also discussed
Risk factors associated with detailed reproductive phenotypes in dairy and beef cows
peer-reviewedThis article was first published in animal, Volume 8, Issue 05, May 2014, pp 695-703, © The Animal Consortium 2014The objective of this study was to identify detailed fertility traits in dairy and beef cattle from transrectal ultrasonography records
and quantify the associated risk factors. Data were available on 148 947 ultrasound observations of the reproductive tract from
75 949 cows in 843 Irish dairy and beef herds between March 2008 and October 2012. Traits generated included (1) cycling at
time of examination, (2) cystic structures, (3) early ovulation, (4) embryo death and (5) uterine score; the latter was measured on a
scale of 1 (good) to 4 (poor) characterising the tone of the uterine wall and fluid present in the uterus. After editing, 72 773
records from 44 415 dairy and beef cows in 643 herds remained. Factors associated with the logit of the probability of a positive
outcome for each of the binary fertility traits were determined using generalised estimating equations; linear mixed model analysis
was used for the analysis of uterine score. The prevalence of cycling, cystic structures, early ovulation and embryo death was
84.75%, 3.87%, 7.47% and 3.84%, respectively. The occurrence of the uterine heath score of 1, 2, 3 and 4 was 70.63%, 19.75%,
8.36% and 1.26%, respectively. Cows in beef herds had a 0.51 odds (95% CI = 0.41 to 0.63, P<0.001) of cycling at the time of
examination compared with cows in dairy herds; stage of lactation at the time of examination was the same in both herd types.
Furthermore, cows in dairy herds had an inferior uterine score (indicating poorer tone and a greater quantity of uterine fluid
present) compared with cows in beef herds. The likelihood of cycling at the time of examination increased with parity and stage of
lactation, but was reduced in cows that had experienced dystocia in the previous calving. The presence of cystic structures on the
ovaries increased with parity and stage of lactation. The likelihood of embryo/foetal death increased with parity and stage of
lactation. Dystocia was not associated with the presence of cystic structures or embryo death. Uterine score improved with parity
and stage of lactation, while cows that experienced dystocia in the previous calving had an inferior uterine score. Heterosis was
the only factor associated with increased likelihood of early ovulation. The fertility traits identified, and the associated risk factors,
provide useful information on the reproductive status of dairy and beef cows.Funding from the Department of Agriculture, Food and Marine Research Stimulus Fund (RSF 11/S/133) and the OptiMIR project is gratefully acknowledged
"Ordinary, the same as anywhere else": notes on the management of spoiled identity in 'marginal' middle class neighbourhoods
Urban sociologists are becoming increasingly interested in neighbourhood as a source of middle-class identity. Particular emphasis is currently being given to two types of middle-class neighbourhood; gentrified urban neighbourhoods of ‘distinction’ and inconspicuous ‘suburban landscapes of privilege’. However, there has been a dearth of work on ‘marginal’ middle-class neighbourhoods that are similarly ‘inconspicuous’ rather than distinctive, but less exclusive, thus containing sources of ‘spoiled identity’. This article draws on data gathered from two ‘marginal’ middleclass neighbourhoods that contained a particular source of ‘spoiled identity’: social renters. Urban sociological analyses of neighbour responses to these situations highlight a process of dis-identification with the maligned object, which exacerbates neighbour differences. Our analysis of data from the ‘marginal’ middle-class neighbourhoods suggests something entirely different and Goffmanesque. This entailed the management of spoiled identity, which emphasized similarities rather than differences between neighbours.</p
Porosity detection in electron beam-melted Ti-6Al-4V using high-resolution neutron imaging and grating-based interferometry
© 2017, Springer International Publishing Switzerland. A high-resolution neutron tomography system and a grating-based interferometer are used to explore electron beam-melted titanium test objects. The high-resolution neutron tomography system (attenuation-based imaging) has a pixel size of 6.4 µm, appropriate for detecting voids near 25 µm over a (1.5 cm)3 volume. The neutron interferometer provides dark-field (small-angle scattering) images with a pixel size of 30 µm. Moreover, the interferometer can be tuned to a scattering length, in this case, 1.97 µm, with a field-of-view of (6 cm)3. The combination of high-resolution imaging with grating-based interferometry provides a way for nondestructive testing of defective titanium samples. A chimney-like pore structure was discovered in the attenuation and dark-field images along one face of an electron beam-melted (EBM) Ti-6Al-4V cube. Tomographic reconstructions of the titanium samples are utilized as a source for a binary volume and for skeletonization of the pores. The dark-field volume shows features with dimensions near and smaller than the interferometer auto-correlation scattering length
Proxima Centauri b is not a transiting exoplanet
We report Spitzer Space Telescope observations during predicted transits of
the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone
planet we will ever discover, any potential transit of Proxima b would place
strong constraints on its radius, bulk density, and atmosphere. Subsequent
transmission spectroscopy and secondary-eclipse measurements could then probe
the atmospheric chemistry, physical processes, and orbit, including a search
for biosignatures. However, our photometric results rule out planetary transits
at the 200~ppm level at 4.5, yielding a 3 upper radius limit
of 0.4~R_\rm{\oplus} (Earth radii). Previous claims of possible transits from
optical ground- and space-based photometry were likely correlated noise in the
data from Proxima Centauri's frequent flaring. Follow-up observations should
focus on planetary radio emission, phase curves, and direct imaging. Our study
indicates dramatically reduced stellar activity at near-to-mid infrared
wavelengths, compared to the optical. Proxima b is an ideal target for
space-based infrared telescopes, if their instruments can be configured to
handle Proxima's brightness.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in MNRA
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