3,186 research outputs found

    The Structural Evolution of the Faroe Islands, NE Atlantic Margin

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    The NE Atlantic margin plays host to numerous basins, developed in phases from the Devono-Carboniferous through to the Cenozoic, which record the build up to plate separation and formation of the North Atlantic Ocean. Existing models for this invoke broadly NW-SE extension within the basins, which are segmented by regional-scale NW-SE trending strike-slip lineaments, which are commonly termed ‘transfer zones’. However, there is a general paucity of information concerning the true kinematics of the so-called transfer zones. In this study, the Palaeogene and later structural evolution of the NE Atlantic margin is investigated using abundant field data collected on the Faroe Islands, and systematic observations that characterise the related deformation structures developed in the Faroe Islands Basalt Group (FIBG). Structures in the Faroe Islands provide evidence for a 6-stage tectonic evolution, here split into 3 broad phases: (1a) E-W to NE-SW extension, accommodated by dip-slip N-S and NW-SE trending faults. Continued NE-SW extension (1b) was then accommodated by the emplacement of a regionally significant NW-SE- and NNE-SSW-oriented dyke swarm. Event 1 affects the majority of the FIBG stratigraphy, resulting in thickness variations, most notably across the Judd, Brynhild and Westray (‘transfer’) fault-zones. Continued magmatism and anticlockwise rotation of the extension vector led to (2a) the emplacement of ENE-WSW and ESE-WNW conjugate dykes, followed by intrusion of the large, saucer-shaped sills on the islands. Their intrusion heralded the onset of N-S crustal extension and was followed by (2b) crustal extrusion involving both E-W shortening and further N-S extension facilitated primarily by slip on ENE-WSW (dextral) and ESE-WNW (sinistral) conjugate strike-slip faults, interlinked with minor NE and SW dipping thrust faults. During the final stages of this event (2c), the regional extension vector rotated into a NW-SE orientation that was accommodated predominantly by slip along NE-SW oriented dextral-oblique-slip faults. Event 2 began towards the end of magmatism associated with the FIBG, and most likely continued through to the onset of oceanic-spreading on the Aegir ridge (ca. 55 Ma). Finally, (3) Event 1 and 2 structures were reactivated as extension and extensional-hybrid features, characterised best by the entrainment of clastic material along fault planes. Relative timings of Event 3 structures suggest they formed during a period of compression and uplift following the formation of a through-going mid-ocean ridge system (i.e. on the Reykjanes, Kolbeinsey and Mohns ridges). The progressive anticlockwise rotation of the extension vector identified here is broadly consistent with the most recent NE Atlantic continental break-up reconstructions. Importantly, this model does not require basin-scale transfer zones during the Palaeogene, suggesting instead that these NW-SE faults formed as normal faults during a pre-cursor margin-parallel extension episode (Event 1) prior to the onset of oceanic spreading in the Faroe-Iceland sector. This study emphasises the importance of carrying out detailed field studies in addition to the more usual regional-scale modelling studies, in order to validate and add further detail to basin kinematic histories. Mineralised syn- to post-magmatic fault sets display a recurring zeolite-calcite-zeolite trend in mineralisation products, which precipitate during successive phases of fault development during each individual event. Fault style and damage zone width appear to be related to the stage of fault development, with early fault/vein meshes linking to form through-going structures with associated damage zones. Dykes and sills are found to form their own fractures, rather than exploiting pre-existing sets. Dyke propagation appears to be buoyancy-driven, with magmatic pressure overcoming the minimum compressive stress. Sills, however, most likely seeded at an interface in the stratigraphy between a weak, more ductile material (i.e. a sedimentary horizon), and a rigid material (i.e. basalt lavas) above. Following this initial development, sill growth and propagation would likely be controlled by viscous dissipation, leading to the complex ramp and flat architecture, with rapid intrusion resulting in upward ramping of the sill. The alternation from fault events, to dyke events and back again corresponds to a switch from faulting with mineralisation along extensional hybrid veins, to magmatic intrusions into extension fractures followed by extensional hybrids (conjugates), and back to extensional and shear hybrid faults (again as conjugates). This alternation reflects variations in the differential regional stress, as well as the magmatic evolution of the margin, and most likely relates to the migration of lithospheric thinning northwestwards across the area, towards the eventual axis of break-up. We find that, in particular, faults in basalts are in many ways comparable to faults formed at shallow crustal depths in carbonate rocks and crystalline basement, most likely reflecting the similarities in their mechanical properties under near-surface pressures and temperatures. The nature and style of the post-magmatic fault infills provides compelling evidence to suggest that subterranean cavities associated with faults were persistent open features within the FIBG. Structures equivalent to these late, clastic-filled faults of the Faroes may occur in other parts of the NE Atlantic margin, particularly along the axes of gentle regional-scale folds that are widely developed in the region. The late fault displacements observed are all well below seismic resolution, and such structures may be more widespread across the region than previously anticipated. Importantly, the probable unsealed nature of the clastic infills makes them potential fluid-migration pathways, both up- and across-faults within the Cenozoic volcanic sequences of the NE Atlantic region

    Multicenter clinical evaluation of the Luminex Aries Flu A/B & RSV assay for pediatric and adult respiratory tract specimens

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    ABSTRACT Influenza A and B viruses and respiratory syncytial virus (RSV) are three common viruses implicated in seasonal respiratory tract infections and are a major cause of morbidity and mortality in adults and children worldwide. In recent years, an increasing number of commercial molecular tests have become available to diagnose respiratory viral infections. The Luminex Aries Flu A/B &amp; RSV assay is a fully automated sample-to-answer molecular diagnostic assay for the detection of influenza A, influenza B, and RSV. The clinical performance of the Aries Flu A/B &amp; RSV assay was prospectively evaluated in comparison to that of the Luminex xTAG respiratory viral panel (RVP) at four North American clinical institutions over a 2-year period. Of the 2,479 eligible nasopharyngeal swab specimens included in the prospective study, 2,371 gave concordant results between the assays. One hundred eight specimens generated results that were discordant with those from the xTAG RVP and were further analyzed by bidirectional sequencing. Final clinical sensitivity values of the Aries Flu A/B &amp; RSV assay were 98.1% for influenza A virus, 98.0% for influenza B virus, and 97.7% for RSV. Final clinical specificities for all three pathogens ranged from 98.6% to 99.8%. Due to the low prevalence of influenza B, an additional 40 banked influenza B-positive specimens were tested at the participating clinical laboratories and were all accurately detected by the Aries Flu A/B &amp; RSV assay. This study demonstrates that the Aries Flu A/B &amp; RSV assay is a suitable method for rapid and accurate identification of these causative pathogens in respiratory infections.</jats:p

    Insulin therapy and dietary adjustments to normalize glycemia and prevent nocturnal hypoglycemia after evening exercise in type 1 diabetes: a randomized controlled trial

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    Introduction Evening-time exercise is a frequent cause of severe hypoglycemia in type 1 diabetes, fear of which deters participation in regular exercise. Recommendations for normalizing glycemia around exercise consist of prandial adjustments to bolus insulin therapy and food composition, but this carries only short-lasting protection from hypoglycemia. Therefore, this study aimed to examine the impact of a combined basal-bolus insulin dose reduction and carbohydrate feeding strategy on glycemia and metabolic parameters following evening exercise in type 1 diabetes. Methods Ten male participants (glycated hemoglobin: 52.4±2.2 mmol/mol), treated with multiple daily injections, completed two randomized study-days, whereby administration of total daily basal insulin dose was unchanged (100%), or reduced by 20% (80%). Participants attended the laboratory at ∼08:00 h for a fasted blood sample, before returning in the evening. On arrival (∼17:00 h), participants consumed a carbohydrate meal and administered a 75% reduced rapid-acting insulin dose and 60 min later performed 45 min of treadmill running. At 60 min postexercise, participants consumed a low glycemic index (LGI) meal and administered a 50% reduced rapid-acting insulin dose, before returning home. At ∼23:00 h, participants consumed a LGI bedtime snack and returned to the laboratory the following morning (∼08:00 h) for a fasted blood sample. Venous blood samples were analyzed for glucose, glucoregulatory hormones, non-esterified fatty acids, β-hydroxybutyrate, interleukin 6, and tumor necrosis factor α. Interstitial glucose was monitored for 24 h pre-exercise and postexercise. Results Glycemia was similar until 6 h postexercise, with no hypoglycemic episodes. Beyond 6 h glucose levels fell during 100%, and nine participants experienced nocturnal hypoglycemia. Conversely, all participants during 80% were protected from nocturnal hypoglycemia, and remained protected for 24 h postexercise. All metabolic parameters were similar. Conclusions Reducing basal insulin dose with reduced prandial bolus insulin and LGI carbohydrate feeding provides protection from hypoglycemia during and for 24 h following evening exercise. This strategy is not associated with hyperglycemia, or adverse metabolic disturbances

    Post academy training needs analysis of selected school district police agencies in Texas

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    One of the fastest growing areas of law enforcement in the state of Texas today is school district policing, with many of the Independent School District (ISD) departments having been formed within the past 10-12 years. Without a formal structured plan of its own, training programs for the school district police officer have often followed the template of other local and state policing organizations to determine their own in-service training curriculum. Unfortunately, following the guidelines and programs set up by these outside policing organizations has led to training that is not indicative of the school district police officers bona fide training needs. This research first focused on identifying the internal and external constraints that are operating from within the school district, along with influences from outside the organization that are hindering ISD police officer training. The results found budgetary issues, time issues, perceived lack of training support from the school district administration, a lack of a training needs analysis to identify training needs, and other outside constraints (such as legislative training mandates), were hindering ISD police in-service training. Recommendations were made to seek outside assistance (grants), combined regional training efforts, organizing to seek changes in required state training mandates, educating administration in ISD policing needs, and performing a training needs analysis to identify training needs. The second focus identified the unique tasks of the school district police officer in order to provide the school district policing organizations with specific task information regarding the daily tasks of the school district police officer. Twenty eight unique police officer tasks were then identified through group sessions held with several ISD policing organizations. The tasks were then listed in order of criticality and frequency, and two lists were made from the returns. One related to overall task importance and the second list was ordered by agency size, as it was believed that the agencies may differ in focus and responsibilities by departmental size. This combination of an organizational analysis and a task analysis is expected to provide the ISD policing organizations with the information from which a sound training program may be designed

    Evidence on the Validity of Management Education

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    The authors feel that more attention should be given to the empirical validation of management education. In order to determine what effect a college degree and the academic major have on promotability, 3,202 marketing personnel of a major petroleum corporation were analyzed. What effect does a college education have on executive success? Does the major area of study make any difference? Does any kind of management education or development yield tangible returns to an employing organization? In other words, have management formal education and development been empirically validated? Many organizations are seriously beginning to ask these questions. The current body of management knowledge has not given a satisfactory answer

    Transcriptional profiling of colicin-induced cell death of Escherichia coli MG1655 identifies potential mechanisms by which bacteriocins promote bacterial diversity

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    We report the transcriptional response of Escherichia coli MG1655 to damage induced by colicins E3 and E9, bacteriocins that kill cells through inactivation of the ribosome and degradation of chromosomal DNA, respectively. Colicin E9 strongly induced the LexA-regulated SOS response, while colicin E3 elicited a broad response that included the induction of cold shock genes, symptomatic of translational arrest. Colicin E3 also increased the transcription of cryptic prophage genes and other laterally acquired mobile elements. The transcriptional responses to both these toxins suggest mechanisms that may promote genetic diversity in E. coli populations, pointing to a more general role for colicins in adaptive bacterial physiology than has hitherto been realized

    Medication adherence in patients with myotonic dystrophy and facioscapulohumeral muscular dystrophy

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    Myotonic dystrophy (DM) and facioscapulohumeral muscular dystrophy (FSHD) are the two most common adult muscular dystrophies and have progressive and often disabling manifestations. Higher levels of medication adherence lead to better health outcomes, especially important to patients with DM and FSHD because of their multisystem manifestations and complexity of care. However, medication adherence has not previously been studied in a large cohort of DM type 1 (DM1), DM type 2 (DM2), and FSHD patients. The purpose of our study was to survey medication adherence and disease manifestations in patients enrolled in the NIH-supported National DM and FSHD Registry. The study was completed by 110 DM1, 49 DM2, and 193 FSHD patients. Notable comorbidities were hypertension in FSHD (44 %) and DM2 (37 %), gastroesophageal reflux disease in DM1 (24 %) and DM2 (31 %) and arrhythmias (29 %) and thyroid disease (20 %) in DM1. Each group reported high levels of adherence based on regimen complexity, medication costs, health literacy, side effect profile, and their beliefs about treatment. Only dysphagia in DM1 was reported to significantly impact medication adherence. Approximately 35 % of study patients reported polypharmacy (taking 6 or more medications). Of the patients with polypharmacy, the DM1 cohort was significantly younger (mean 55.0 years) compared to DM2 (59.0 years) and FSHD (63.2 years), and had shorter disease duration (mean 26 years) compared to FSHD (26.8 years) and DM2 (34.8 years). Future research is needed to assess techniques to ease pill swallowing in DM1 and to monitor polypharmacy and potential drug interactions in DM and FSHD

    Evidence of Uppermost Proterozoic to Lower Cambrian miogeoclinal rocks and the Mojave-Snow Lake Fault: Snow Lake Pendant, central Sierra Nevada, California

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    This is the published version. Copyright 2010 American Geophysical Union. All Rights Reserved.Displaced uppermost Precambrian to Lower Cambrian miogeoclinal strata occur within Snow Lake pendant in the central Sierra Nevada. These rocks have been correlated with the Stirling Quartzite, the Wood Canyon Formation, the Zabriskie Quartzite, and the Carrara Formation in the western Mojave Desert and the San Bernardino Mountains (Lahren and Schweickert, 1989; Lahren, 1989). This correlation is based on new, updated, and previously reported data including (1) lithologic similarities, (2) overall stratigraphic sequence, (3) vertical sequence within individual formations, (4) approximate stratigraphic thicknesses, (5) Skolithos in the correct stratigraphie position, (6) depositional environments, and (7) petrographic character and provenance of quartz arenites. The correlation is strengthened by the fact that Snow Lake pendant and the western Mojave share many other close similarities including (1) initial 87Sr/86Sr ratios of associated granitic rocks >0.706, (2) passive margin tectonic setting of Precambrian to Cambrian miogeoclinal rocks, (3) dikes of the Independence dike swarm, (4) possible Lower Triassic overlap sequence, the Fairview Valley Formation, (5) petrographically similar gabbroic complexes of the same age, (6) associated eugeoclinal rocks, and (7) identical(?) pre-Tertiary structural configuration. New U/Pb zircon geochronology unequivocally shows that dikes at Snow Lake pendant are coeval with the Independence dike swarm of the eastern Sierra and the western Mojave desert and that associated gabbroic complexes in both the Mojave and Snow Lake pendant are the same age. Correlation of Snow Lake pendant with the western Mojave requires about 400 km of dextral displacement of the rocks of Snow Lake pendant, together with associated rocks (Snow Lake block), from the western Mojave Desert along the Mojave-Snow Lake fault. Displacement most likely occurred after 150 Ma, the age of the Independence dike swarm, and before about 110 Ma, the age of major plutons within the Sierra Nevada batholith. This interpretation, if correct, holds major implications for allochthonous terranes west of Snow Lake pendant, which were probably attached to the Snow Lake block before its northward transport. In addition, a number of Paleozoic and Mesozoic tectonic features in western Nevada and eastern California may have been offset dextrally along the proposed Mojave-Snow Lake fault

    Oroclinal bending, distributed thrust and strike-slip faulting, and the accommodation of Arabia–Eurasia convergence in NE Iran since the Oligocene

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    Regional shortening is accommodated across NE Iran in response to the collision of Arabia with Eurasia. We examine how N–S shortening is achieved on major thrust systems bounding the eastern branch of the Alborz (east of 57°E), Sabzevar and Kuh-e-Sorkh mountain ranges, which lie south of the Kopeh Dagh mountains in NE Iran. Although these ranges have experienced relatively few large earthquakes over the last 50 yr, they have been subject to a number of devastating historical events at Neyshabur, Esfarayen and Sabzevar. A significant change in the tectonics of the eastern Alborz occurs directly south of the Central Kopeh Dagh, near 57°E. To the east, shortening occurs on major thrust faults which bound the southern margin of the range, resulting in significant crustal thickening, and forming peaks up to 3000 m high. Active shortening dies out eastward into Afghanistan, which is thought to belong to stable Eurasia. The rate of shortening across thrust faults bounding the south side of the eastern Alborz north of Neyshabur is determined using optically stimulated luminescence dating of displaced river deposits, and is likely to be 0.4–1.7 mm yr^(−1). Shortening across the Sabzevar range 150 km west of Neyshabur has previously been determined at 0.4–0.6 mm yr^(−1), although reassessment of the rate here suggests it may be as high as 1 mm yr^(−1). Migration of thrust faulting into foreland basins is common across NE Iran, especially in the Esfarayen region near 57°E, where the northward deflection of the East Alborz range reaches a maximum of 200 ± 20 km (from its presumed linear E–W strike at the beginning of the Oligocene). West of 57°E, the tectonics of the Alborz are affected by the westward motion of the South Caspian region, which results in the partitioning of shortening onto separate thrust and left-lateral strike-slip faults north and south of the range. At the longitude of 59°E, published GPS velocities indicate that 50 per cent of the overall shortening across NE Iran is accommodated in the Kopeh Dagh. The remaining 50 per cent regional shortening must therefore be accommodated south of the Kopeh Dagh, in the eastern Alborz and Kuh-e-Sorkh ranges. Assuming present day rates of slip and the fault kinematics are representative of the Late Cenozoic deformation in NE Iran, the total 200 ± 20 km N–S shortening across the eastern Alborz and Kopeh Dagh mountains since the beginning of uplift of the Kopeh Dagh basin would be accommodated in 30 ± 8 Ma. Although this extrapolation may be inappropriate over such a long timescale, the age is nevertheless consistent with geological estimates of post Early-to-Middle Oligocene (<30 Ma) for the onset of Kopeh Dagh uplift
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