284 research outputs found

    Geochemistry and Origins of Thermal Springs Waters of the Olympic Peninsula and Cascade Range, Washington

    Get PDF
    The state of Washington contains 98 low temperature (surface temperatures between ~ 20 - 50 oC) geothermal springs, which are powered by the convective circulation of groundwater that is heated by the natural heat of the Earth. These systems operate in a cycle that begins when precipitation percolates downward into the subsurface and comes in contact with a heat source. Subsequently the heated water returns to the surface, in most cases, having interacted chemically with rocks in the reservoir and/or along its ascent path. Surveys done by the USGS between the 1970s – early 1990s show there is significant chemical variation amongst these thermal springs. The objective of this research is to investigate the origins of this chemical diversity. Using water chemistry and isotopic data, the study has been able to suggest the following: Estimated subsurface water temperatures are indicative of low-temperature geothermal systems The dominant component of spring waters is meteoric in origin The springs are most likely representative of outflow-type structures Geothermal systems in Cascade Arc are volcanically hosted while systems in the Olympic Peninsula are presumed to be fault-controlled convective cell

    Effect of Organo Montmorillonite Nanoclay on Mechanical Properties Thermal Stability and Ablative Rate of Carbon fiber Polybenzoxazine Resin Composites

    Get PDF
    Organo-Montmorillonite (o-MMT) nanoclay added polybenzoxazine resin (type I composites) were prepared with varying amounts of clay (0, 1, 2, 4 and 6 wt %). Clay dispersion, changes in curing behaviour and thermal stability were assessed in type I composites. Findings from these studies of type I composites were used to understand thermal stability, mechanical, and mass ablation rate behaviour of nanoclay added carbon fiber reinforced polybenzoxazine composites (type II). Interlaminar shear strength and flexural strength of type II composites increase by 25% and 27%, respectively at 2 wt% addition of clay. An oxy-acetylene torch test with a constant heat flux of 125 w/cm2 was used to investigate mass ablation rate of type II composites. The ablation rate has increased as the weight percentage of clay has increased. This is contradicting to type I composites with up to 6 wt% clay and type II composites with up to 4 wt% clay, which have improved thermal stability. The microstructure of the ablated composites was examined using scanning electron microscopy. Increased ablation rates are due to the reaction of charred matrix with nanoclay, which exposes bare fibers to the ablation front, resulting in higher mechanical erosion losses

    A new medication-based prediction score for postoperative delirium in surgical patients: development and proof of feasibility in a retrospective patient cohort

    Get PDF
    Structured risk screening for postoperative delirium (POD) considering prehospital medication is not established. We aimed to develop a POD-risk prediction score based on known risk factors and delirium-risk increasing drugs to be used by pharmacists during medication reconciliation at hospital admission, and to test for feasibility in a retrospective cohort of surgical patients. Therefore, established POD-risk factors and drugs were extracted from the literature and a score was generated. Following this, the score was tested for feasibility in a retrospective 3-month-cohort of surgical patients. For patients with higher scores suggesting higher probability of POD, patient charts were screened for documentation of POD. For development of the score, the following POD-risk factors were defined and points assigned for score calculation: age (≥65 years=1 point/≥75 years=2), male sex (1), renal insufficiency (RI; 1), hepatic impairment (HI; Model-of-endstage-liver-disease (MELD) 10-14=1/≥15=2), delirium-risk increasing drugs (1 point per drug class), anticholinergic drug burden (ACB; ≥3=1). In the retrospective test cohort of 1174 surgical patients these factors concerned: age ≥65 years 567 patients (48%)/≥75 years 303 (26%), male 652 (55%), RI 238 (20%), MELD 10-14 106 (9%)/≥15 65 (5%), ≥ 1 delirium-risk increasing drug 418 (36%), ACB ≥3 106 (9%). The median POD-risk prediction score was 2 (range 0-9). Of 146 patients (12%) with a score ≥ 5, POD was documented for 43 (30%), no evidence for POD for 91 (62%) and data inconclusive for 12 (8%). For scores of ≥ 7, POD was documented for 50% of the patients with sufficient POD documentation. Overall, POD documentation was poor. To summarize, we developed and successfully tested the feasibility of a POD-prediction-score assessable by pharmacists at medication reconciliation at hospital admission

    Natural trace element salinization of the Jemez River, New Mexico by geothermal springs and major tributaries

    Get PDF
    The Jemez River (JR), a tributary of the Rio Grande, is in north-central New Mexico within the Jemez Mountains, which houses the active, high-temperature (≤ 300 oC), liquid-dominated Valles Caldera geothermal system (VC). This work focuses on the northern portion of the JR, spanning a reach from the East Fork JR to the town of San Ysidro. Previous decadal work during low-flow or baseflow conditions (~10-20 cfs) has identified and characterized significant major-solute contributions from two outflow expressions of the VC, Soda Dam Springs and Jemez Hot Springs, and two major tributaries, Rio San Antonio and Rio Guadalupe. There is generally a net ~500-ppm increase from below Soda Dam to the end of the study segment. The distribution of concentrations of twenty-four trace metals from recent Fall 2017 sampling are defined by range from \u27ultra-trace\u27 levels (0.1-1 ppb) to measurements as much as 1 ppm. A set of elements (e.g., As, Li, Rb, Ba, Ti) follows the same downstream behavior of major ions, which is characterized by an increase in concentrations at each inflow and the observed greatest contribution (as much as an order of magnitude) is at Soda Dam. Another group (e.g., U, Al, Fe, Mn, Se) shows complex downstream patterns, which may be a result of non-conservative processes, such as precipitation/dissolution, sorption, and complexation. We attempt to resolve these potential in-stream processes with high-resolution (regular 1-km spacing with interspersed 50-m intervals around sites with complete chemistry) spatial surveys of temperature, dissolved oxygen, pH, oxidation-reduction potential, and turbidity

    Space Use and Movement of Urban Bobcats

    Get PDF
    Global urbanization is rapidly changing the landscape for wildlife species that must learn to persist in declining wild spacing, adapt, or risk extinction. Many mesopredators have successfully exploited urban niches, and research on these species in an urban setting offers insights into the traits that facilitate their success. In this study, we examined space use and activity patterns from GPS-collared bobcats (Lynx rufus) in the Dallas–Fort Worth metroplex, Texas, USA. We found that bobcats select for natural/agricultural features, creeks, and water ways and there is greater home-range overlap in these habitats. They avoid roads and are less likely to have home-range overlap in habitats with more roads. Home-range size is relatively small and overlap relatively high, with older animals showing both greater home-range size and overlap. Simultaneous locations suggest bobcats are neither avoiding nor attracted to one another, despite the high overlap across home ranges. Finally, bobcats are active at all times of day and night. These results suggest that access to natural features and behavioral plasticity may enable bobcats to live in highly developed landscapes

    The magnetic environment in the central region of nearby galaxies

    Full text link
    The central regions of galaxies harbor some of the most extreme physical phenomena, including dense stellar clusters, non-circular motions of molecular clouds and strong and pervasive magnetic field structures. In particular, radio observations have shown that the central few hundred parsecs of our Galaxy has a striking magnetic field configuration. It is not yet clear whether these magnetic structures are unique to our Milky Way or a common feature of all similar galaxies. Therefore, we report on (a) a new radio polarimetric survey of the central 200 pc of the Galaxy to better characterize the magnetic field structure and (b) a search for large-scale and organized magnetized structure in the nuclear regions of nearby galaxies using data from the Very Large Array (VLA) archive. The high angular resolution of the VLA allows us to study the central 1 kpc of the nearest galaxies to search for magnetized nuclear features similar to what is detected in our own Galactic center. Such magnetic features play a important role in the nuclear regions of galaxies in terms of gas transport and the physical conditions of the interstellar medium in this unusual region of galaxies.Comment: 8 pages; Proceedings for "The Universe under the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal of Physics: Conference Series by Institute of Physics Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.

    Effect of different Sowing Windows on Major Insect Pests and Host Plant Resistance to Pod Borer, Helicoverpa armigera in Pigeonpea (Cajanus cajan (L.) Millsp.)

    Get PDF
    Effect of sowing dates, climatic variables on major insect pests population, and host plant resistance with special reference to pod borer Helicoverpa armigera (Hubner) in pigeon pea (Cajanus cajan (L.) ecosystem was studied on two cultivars namely, ICPL 87 and ICPL 88039. The insect pest population on two cultivars differed significantly across sowing dates. ICPL 87 was most vulnerable to insect pests as it suffered more damage by the pod borer H. armigera, pod sucking bugs (Clavigralla tomentosicollis Stal.) than ICPL 88039. The maximum leaf/pod feeding insect population was recorded on first sowing and then gradually decline for the rest of the plantings. Maximum H. armigera egg population exhibited 21.10 on ICPL 87 in first sowing and at least 1.23 on ICPL 88039 in sixth sowing. Web forming insect pests Maruca virata (3.95) and leaf webber (4.66) weremaximum recorded on ICPL 88039 in second and first planting respectively. The leaf feeding beetle was recorded highest 6.29(ICPL 87) in the third planting. Amid two cultivars maximum insect-pests population was recorded on ICPL 87 when compared to ICPL 88039 except web forming insect Maruca and leaf webber due to its indeterminate genotypic character of ICPL 88039. Between the two genotypes, the sucking pests more preferred to ICPL 87 when compared ICPL 88039. Maximum jassids were recorded 12.76 and 8.38 (ICPL 87) in fourth sowing and third sowing respectively. It was observed that highest spider population recorded 2.23(ICPL 88039) in first and second sowing. Ladybird beetle Coccinella transvasalis population recorded a maximum 8.52 (ICPL 87). The leaf webber (r= 0.449**) and pod bug (r= 0.421**) showed a highly significant positive correlation with maximum temperature and H. armigera larvae population exhibited highly significant positive correlation with minimum temperature (r= 0.491**) and morning relative humidity (r= 0.528**). Solar radiation also exhibited and showed a significant positive correlation with leaf webber (r= 533**)

    Risk factors and coronary angiographic profile in young STEMI patients: results from a tertiary care centre in south-central India

    Get PDF
    Background: Compared to older counterparts, a significant distinction has been found related to risk factors, clinical presentation, and prognosis of ST-segment elevation myocardial infarction (STEMI) in younger patients. To date, a lack of studies has been looked, specifically at-risk factors and angiographic profile of STEMI among younger patients; with this in mind, we conducted the present study.Methods: This hospital-based, cross-sectional, open-label study was carried out at Deccan College of Medical Sciences between April 2018 and December 2019. Patients under 40 years with the presentation of STEMI were included. All patients were subjected to electrocardiography, 2D echocardiography, and coronary angiogram. Baseline demographics, risk factors, and procedural characteristics were recorded.Results: Of 51 young STEMI patients, 41 (80.4%) were male and 10 (19.6%) were female. The most common risk factors associated with the development of STEMI in young patients were smoking (58.8%), followed by diabetes (45.1%), and dyslipidaemia (45.1%). Anterior wall MI was the most frequent presentation (84.3%). The left anterior descending artery was the most frequently (62.8%) involved vessel, followed by left circumflex artery (9.8%), and right coronary artery (5.9%).Conclusions: Insights gained from the study can aid in identifying clinical characteristics of STEMI in young patients, which may be beneficial to achieve appropriate and timely management. Further, the young population should be educated as to control modifiable risk factors and smoking cessation to prevent coronary artery disease since they belong to the highly productive group in the community

    High Latitude Radio Emission in a Sample of Edge-On Spiral Galaxies

    Get PDF
    We have mapped 16 edge-on galaxies at 20 cm using the VLA. For 5 galaxies, we could form spectral index, energy and magnetic field maps. We find that all but one galaxy show evidence for non-thermal high latitude radio continuum emission, suggesting that cosmic ray halos are common in star forming galaxies. The high latitude emission is seen over a variety of spatial scales and in discrete and/or smooth features. In general, the discrete features emanate from the disk, but estimates of CR diffusion lengths suggest that diffusion alone is insufficient to transport the particles to the high latitudes seen (> 15 kpc in one case). Thus CRs likely diffuse through low density regions and/or are assisted by other mechanisms (e.g. winds). We searched for correlations between the prevalence of high latitude radio emission and a number of other properties, including the global SFR, supernova input rate per unit star forming, and do not find clear correlations with any of these properties.Comment: 40 pages of text, 3 figures, 6 tables, and an appendix of 21 jpeg figures (which is a radio continuum catalogue of 17 galaxies). to appear in A. J. (around January 1999
    corecore