705 research outputs found

    Resonance capture of neutrons in infinite homogeneous media

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    In a previous paper, a variational principle was introduced for 1 - p, the capture probability for neutrons slowing down in a homogeneous medium of infinite extent. In the present paper, the variational principle is used together with simple but accurate trial functions to obtain expressions for (i) corrections to the commonly used 'narrow resonance' formula for capture and (ii) interference effects in the capture of neutrons by closely spaced resonances

    Bio + Region = BIOREGION? Ein Workshop im Rahmen der Wissenschaftstagung

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    Das Konzept der "Bioregion" als Verbindung nachhaltiger regionaler Entwicklung und biologischer Landwirtschaft gewinnt zunehmend an Bedeutung. In den Medien erscheinen immer wieder Berichte ĂŒber neue Initiativen zur Errichtung von Bioregionen in allen Teilen Österreichs. Was allerdings darunter im allgemeinen zu verstehen ist, ist nicht immer klar

    Temperature-Time History of Subducted Continental-Crust, Mount Olympos Region, Greece

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    In the Mt. Olympos region of northeastern Greece, continental margin strata and basement rocks were subducted and metamorphosed under blueschist facies conditions, and thrust over carbonate platform strata during Alpine orogenesis. Subsequent exposure of the subducted basement rocks by normal faulting has allowed an integrated study of the timing of metamorphism, its relationship to deformation, and the thermal history of the subducted terrane. Alpine low-grade metamorphic assemblages occur at four structural levels. Three thrust sheets composed of Paleozoic granitic basement and Mesozoic metasedimentary cover were thrust over Mesozoic carbonate rocks and Eocene flysch; thrusting and metamorphism occurred first in the highest thrust sheets and progressed downward as units were imbricated from NE to SW. 40Ar/39Ar spectra from hornblende, white mica, and biotite samples indicate that the upper two units preserve evidence of four distinct thermal events: (1) 293–302 Ma crystallization of granites, with cooling from \u3e550°C to \u3c325°C by 284 Ma; (2) 98–100 Ma greenschist to blueschist-greenschist transition facies metamorphism (T∌350–500°C) and imbrication of continental thrust sheets; (3) 53–61 Ma blueschist facies metamorphism and deformation of the basement and continental margin units at T\u3c350–400°C; (4) 36–40 Ma thrusting of blueschists over the carbonate platform, and metamorphism at T∌200–350°C. Only the Eocene and younger events affected the lower two structural packages. A fifth event, indicated by diffusive loss profiles in microcline spectra, reflects the beginning of uplift and cooling to T\u3c100–150°C at 16–23 Ma, associated with normal faulting which continued until Quaternary time. Incomplete resetting of mica ages in all units constrains the temperature of metamorphism during continental subduction to T≀350°C, the closure temperature for Ar in muscovite. The diffusive loss profiles in micas and K-feldspars enable us to “see through” the younger events to older events in the high-T parts of the release spectra. Micas grown during earlier metamorphic events lost relatively small amounts of Ar during subsequent high pressure-low temperature metamorphism. Release spectra from phengites grown during Eocene metamorphism and deformation record the ages of the Ar-loss events. Alpine deformation in northern Greece occurred over a long time span (∌90 Ma), and involved subduction and episodic imbrication of continental basement before, during, and after the collision of the Apulian and Eurasian plates. Syn-subduction uplift and cooling probably combined with intermittently higher cooling rates during extensional events to preserve the blueschist facies mineral assemblages as they were exhumed from depths of \u3e20 km. Extension in the Olympos region was synchronous with extension in the Mesohellenic trough and the Aegean back-arc, and concurrent with westward-progressing shortening in the external Hellenides

    A Pilot Study of Bibliotherapy to Reduce Alcohol Problems among Patients in a Hospital Trauma Center

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    Because alcohol use plays a major role in many injuries that require hospital care, there is increasing interest in developing interventions to address alcohol problems among emergency department and trauma center patients. The aim of the current study was to extend past research on brief interventions by investigating the use of a self-help manual to treat problem drinkers in a hospital trauma center. Forty injured patients who were either intoxicated at the time of injury or screened positive for harmful drinking were randomly assigned to receive either a brief assessment and a self-help booklet with no more than 5 minutes clinician contact (bibliotherapy) or brief assessment only. Follow-up data obtained five months after hospital discharge indicated that patients in both conditions made significant reductions in drinking and associated negative consequences. There was a trend toward further treatment-seeking among those in the bibliotherapy condition (40% versus 13%). Results suggest that the provision of self-help materials to treat problem drinkers identified in a hospital trauma setting may not bring about behavior change beyond that observed following hospitalization and an assessment of drinking. Caution in the interpretation of results is warranted due to the small sample size

    The resilience and vulnerability of remote mountain communities: The case of Vent, Austrian Alps

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    © 2017 Elsevier Ltd Building on critical community resilience studies, this study analyses the resilience of the village of Vent, a remote mountain community in the Austrian Ötztal valley challenged by slow-onset disturbances such as climate change, outmigration of young people and the repercussions of the post-2008 recession. A conceptual framework which focuses on how well economic, social, cultural, political and natural domains are developed within a community, is used as the conceptual springboard to assess the resilience of Vent. The study highlights that Vent is facing substantial resilience challenges and that the community is particularly vulnerable (weak resilience) with regard to the political and natural domains, is only moderately resilient in economic and social terms, and that only the cultural domain emerges as strongly resilient. Overall, Vent is, at most, moderately resilient in the face of continuing and future shocks/disturbances. The study interrogates current resilience frameworks and suggests that an approach based on the five resilience domains provides a richly textured framework for understanding the subtleties of resilience pathways, all the while acknowledging that obtaining a relatively complete picture of resilience is easier in small (and geographically bounded) communities

    Post-Caledonian Brittle Fault Zones on the Hyperextended SW Barents Sea Margin: New Insights into Onshore and Offshore Margin Architecture

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    Onshore-offshore correlation of brittle faults and tectonic lineaments has been undertaken along the SW Barents Sea margin off northern Norway. The study has focused on onshore mapping of fault zones, the mapping of offshore fault complexes and associated basins from seismic interpretation, and the linkage of fault complexes onshore and offshore by integrating a high-resolution DEM, covering both onshore and offshore portions of the study area, and processed magnetic anomaly data. This study shows that both onshore and offshore brittle faults manifest themselves mainly as alternating NNE–SSW- and ENE–WSW-trending, steeply to moderately dipping, normal fault zones constituting at least two major NE-SW-trending fault complexes, the Troms-Finnmark and Vestfjorden-Vanna fault complexes. These fault complexes in western Troms bound a major basement horst (the West Troms Basement Complex), run partly onshore and offshore and link up with the offshore Nysleppen and MĂ„sĂžy fault complexes. Pre-existing structures in the basement, such as foliation, lithological boundaries and ductile shear zones are shown, at least on a local scale, to have exerted a controlling effect on faulting. On a larger scale, at least two major transfer fault zone systems, one along the reactivated Precambrian Senja Shear Belt and the other, the FuglĂžya transfer zone, accommodate changes in brittle fault polarity along the margin. Our results suggest that distributed rifting during Carboniferous and Late Permian/Early Triassic time was followed by a northwestward localisation of displacement to the Troms–Finnmark and RingvassĂžy–Loppa fault complexes during the Late Jurassic/Early Cretaceous, resulting in the formation of a short-tapered, hyperextended margin with final break-up at ~55 Ma. An uplift of the margin and preservation of the West Troms Basement Complex as a basement outlier is suggested to be due to unloading and crustal flexure of the short-tapered margin in the region

    Association between intravenous chloride load during resuscitation and in-hospital mortality among patients with SIRS

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    PURPOSE: Recent data suggest that both elevated serum chloride levels and volume overload may be harmful during fluid resuscitation. The purpose of this study was to examine the relationship between the intravenous chloride load and in-hospital mortality among patients with systemic inflammatory response syndrome (SIRS), with and without adjustment for the crystalloid volume administered. METHODS: We conducted a retrospective analysis of 109,836 patients ≄18 years old that met criteria for SIRS and received fluid resuscitation with crystalloids. We examined the association between changes in serum chloride concentration, the administered chloride load and fluid volume, and the ‘volume-adjusted chloride load’ and in-hospital mortality. RESULTS: In general, increases in the serum chloride concentration were associated with increased mortality. Mortality was lowest (3.7 %) among patients with minimal increases in serum chloride concentration (0–10 mmol/L) and when the total administered chloride load was low (3.5 % among patients receiving 100–200 mmol; P < 0.05 versus patients receiving ≄500 mmol). After controlling for crystalloid fluid volume, mortality was lowest (2.6 %) when the volume-adjusted chloride load was 105–115 mmol/L. With adjustment for severity of illness, the odds of mortality increased (1.094, 95 % CI 1.062, 1.127) with increasing volume-adjusted chloride load (≄105 mmol/L). CONCLUSIONS: Among patients with SIRS, a fluid resuscitation strategy employing lower chloride loads was associated with lower in-hospital mortality. This association was independent of the total fluid volume administered and remained significant after adjustment for severity of illness, supporting the hypothesis that crystalloids with lower chloride content may be preferable for managing patients with SIRS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00134-014-3505-3) contains supplementary material, which is available to authorized users

    Comprehensive self management and routine monitoring in chronic obstructive pulmonary disease patients in general practice: randomised controlled trial

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    OBJECTIVE To assess the long term effects of two different modes of disease management (comprehensive self management and routine monitoring) on quality of life (primary objective), frequency and patients' management of exacerbations, and self efficacy (secondary objectives) in patients with chronic obstructive pulmonary disease (COPD) in general practice. DESIGN 24 month, multicentre, investigator blinded, three arm, pragmatic, randomised controlled trial. SETTING 15 general practices in the eastern part of the Netherlands. PARTICIPANTS Patients with COPD confirmed by spirometry and treated in general practice. Patients with very severe COPD or treated by a respiratory physician were excluded. INTERVENTIONS A comprehensive self management programme as an adjunct to usual care, consisting of four tailored sessions with ongoing telephone support by a practice nurse; routine monitoring as an adjunct to usual care, consisting of 2-4 structured consultations a year with a practice nurse; or usual care alone (contacts with the general practitioner at the patients' own initiative). OUTCOME MEASURES The primary outcome was the change in COPD specific quality of life at 24 months as measured with the chronic respiratory questionnaire total score. Secondary outcomes were chronic respiratory questionnaire domain scores, frequency and patients' management of exacerbations measured with the Nijmegen telephonic exacerbation assessment system, and self efficacy measured with the COPD self-efficacy scale. RESULTS 165 patients were allocated to self management (n=55), routine monitoring (n=55), or usual care alone (n=55). At 24 months, adjusted treatment differences between the three groups in mean chronic respiratory questionnaire total score were not significant. Secondary outcomes did not differ, except for exacerbation management. Compared with usual care, more exacerbations in the self management group were managed with bronchodilators (odds ratio 2.81, 95% confidence interval 1.16 to 6.82) and with prednisolone, antibiotics, or both (3.98, 1.10 to 15.58). CONCLUSIONS Comprehensive self management or routine monitoring did not show long term benefits in terms of quality of life or self efficacy over usual care alone in COPD patients in general practice. Patients in the self management group seemed to be more capable of appropriately managing exacerbations than did those in the usual care group. TRIAL REGISTRATION Clinical trials NCT00128765.This study was funded by the Netherlands Organisation for Health Research and Development (ZonMw) and Partners in Care Solutions for COPD (PICASSO). The funding sources had no role in the design, conduct, or reporting of the stud

    Late Cenozoic Structure and Tectonics of the Northern Mojave Desert

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    In the Fort Irwin region of the northern Mojave desert, late Cenozoic east striking sinistral faults predominate over northwest striking dextral faults of the same age. Kinematic indicators and offset marker units indicate dominantly sinistral strike slip on the east striking portions of the faults and sinistral-thrust slip on northwest striking, moderately dipping segments at the east ends of the blocks. Crustal blocks ∌7–10 km wide by ∌50 km long are bounded by complex fault zones up to 2 km wide at the edges and ends of each block. Faulting initiated after ∌11 Ma, and Quaternary deposits are faulted and folded. We document a minimum of 13 km cumulative sinistral offset in a north-south transect from south of the Bicycle Lake fault to north of the Drinkwater Lake fault. Paleomagnetic results from 50 sites reveal two direction groups in early and middle Miocene rocks. The north-to-northwest declinations of the first group are close to the middle Miocene reference pole. However, rock magnetic studies suggest that both primary and remagnetized directions are present in this group. The northeast declinations of the second group are interpreted as primary and 63.5° ± 7.6° clockwise from the reference pole and suggest net post middle Miocene clockwise rotation of several of the east trending blocks in the northeast Mojave domain. The Jurassic Independence Dike Swarm in Fort Irwin may be rotated 25–80° clockwise relative to the swarm north of the Garlock fault, thus supporting the inference of clockwise rotation. Using a simple-shear model that combines sinistral slip and clockwise rotation of elongate crustal blocks, we predict ∌23° clockwise rotation using the observed fault slip, or one-third that inferred from the paleomagnetic results. The discrepancy between slip and rotation may reflect clockwise bending at the ends of fault blocks, where most of our paleomagnetic sites are located. However, at least 25°–40° of clockwise tectonic rotation is consistent with the observed slip on faults within the domain plus possible “rigid-body” rotation of the region evidenced by clockwise bending of northwest striking domain-bounding faults. Our estimates of sinistral shear and clockwise rotation suggest that approximately half of the 65 km of dextral shear in the Eastern California Shear Zone over the last 10 m.y. occurred within the northeast Mojave Domain. The remainder must be accommodated in adjacent structural domains, e.g., east of the Avawatz Mountains and west of the Goldstone Lake fault. Supporting Appendices 1 and 2 are available on diskette or via Anonymous FTP from kosmos.agu.org, directory APEND (Username -- anonymous, Password = guest). Diskette may be ordered from American Geophysical Union, 2000 Florida Avenue, N.W, Washington, DC 20009 or by phone at 800-966-2481; $15.00. Payment must accompany order
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