101 research outputs found

    Subsonic Flight Tests of a 1/7-Scale Radio-Controlled Model of the North American X-15 Airplane with Particular Reference to High Angel-of-Attack Conditions

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    An investigation of the subsonic stability and control characteristics of an unpowered 1/7-scale model based on the North American X-15 airplane was conducted by using a radio-controlled model launched from a helicopter and flown in free-gliding flight. At angles of attack below about 20 deg. where the model motions represent those of the X-15 airplane, the model was found to be both longitudinally and laterally stable, and the all-movable tail surfaces were found to be very effective. The model could also be flown at much higher angles of attack where the model motions did not necessarily represent those of the airplane because of slight geometrical differences and Reynolds number effects, but these test results are useful in evaluating the effectiveness at these angles of the type of lateral control system used in the X-15 airplane. In some cases, the model was flown to angles of attack as high as 60 or 70 deg. without encountering divergent or uncontrollable conditions. For some flights in which the model was subjected to rapid maneuvers, spinning motions were generated by application of corrective controls to oppose the direction of rotation. Rapid recoveries from this type of motion were achieved by applying roll control in the direction of rotation

    Accounting education literature review (2017)

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    This review of the accounting education literature includes 103 articles published during 2017 in six journals: (1) Journal of Accounting Education, (2) Accounting Education, (3) Advances in Accounting Education: Teaching and Curriculum Innovations, (4) Global Perspectives on Accounting Education, (5) Issues in Accounting Education, and (6) The Accounting Educators’ Journal. We update 12 prior accounting education literature reviews by organizing and summarizing contributions to the accounting education literature made during 2017. Articles are categorized into five sections corresponding to traditional knowledge bases: (1) curriculum and instruction, (2) instruction by content area, (3) educational technology, (4) students, and (5) faculty. Research rigor of the empirical articles is discussed and critiqued. Suggestions for research in all areas are presented. Articles classified as instructional resources and cases published in the same six journals during 2017 are listed in appendices categorized by the relevant content area

    Compilation of Selected Vegetable Crop Reports Dealing with Research and Demonstration Plots Located at the Muck Crops Branch, 1983

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    Spinach cultivar trials, 1982 ; Celery cultivar trials, 1982 / James M. Pisarczyk and Richard L. Hassell -- Potato cultivar trials, 1982 / James M. Pisarczyk -- Celery transplant study, 1982 / Richard L. Hassell -- Parsley 1982 variety trials ; Onion 1982 variety trials ; Broccoli variety trials, 1982 / Richard L. Hassell -- Carrot variety trials, 1982 / R. Mack Riedel and Richard C. Henne -- Control of early blight of celery with fungicides, 1982 ; Control of crucifer downy mildew with fungicide sprays, 1982 / Randall C. Rowe and Richard L. Hassell -- Synergistic interaction between species of lesion nematodes and Verticillium dahliae, 1982 / R. M. Riedel and R. C. Rowe -- Transplants vs. bare-root in controlling root-knot nematode / R. M. Riedel -- Rotations for control of root-knot nematode / R. M. Riedel and J. A. Chatfield -- Fertilizer guidelines for vegetable crops grown on muck soils in Ohio / William M. Brooks, E. C. Wittmeyer and Richard Hassel

    Detection of Varicella Zoster Virus Antigen and DNA in Two Cases of Cerebral Amyloid Angiopathy

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    OBJECTIVE: Varicella zoster virus (VZV) vasculopathy and cerebral amyloid angiopathy (CAA) have similar clinical presentations: both affect cerebrovasculature in the elderly, produce hemorrhage, and can have a protracted course of cognitive decline and other neurological deficits. The cause of CAA is unknown, but amyloid-beta (Aβ) is found within arterial walls. Recent studies show that VZV induces Aβ and amylin expression and an amyloid-promoting environment. Thus, we determined if VZV was present in CAA-affected arteries. METHODS: Two subjects with pathologically-verified CAA were identified postmortem and frontal lobes analyzed by immunohistochemistry for arteries containing VZV, Aβ, and amylin and H&E for pathological changes. VZV antigen detection was confirmed by PCR for VZV DNA in the same region. RESULTS: In both CAA cases, sections with cerebral arteries containing VZV antigen with corresponding VZV DNA were identified; VZV antigen co-localized with Aβ in media of arteries with histological changes characteristic of CAA. Amylin was also seen in the intima of a VZV-positive artery in the diabetic subject. Not all Aβ-containing arteries had VZV, but all VZV-positive arteries contained Aβ. CONCLUSIONS: VZV antigen co-localized with Aβ in some affected arteries from two CAA cases, suggesting a possible association between VZV infection and CAA

    Risk factors for death in 632 patients with sickle cell disease in the United States and United Kingdom

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    Background: The role of pulmonary hypertension as a cause of mortality in sickle cell disease (SCD) is controversial. Methods and Results: We evaluated the relationship between an elevated estimated pulmonary artery systolic pressure and mortality in patients with SCD. We followed patients from the walk-PHaSST screening cohort for a median of 29 months. A tricuspid regurgitation velocity (TRV)≥3.0 m/s cuttof, which has a 67-75% positive predictive value for mean pulmonary artery pressure ≥25 mm Hg was used. Among 572 subjects, 11.2% had TRV≥3.0 m/sec. Among 582 with a measured NT-proBNP, 24.1% had values ≥160 pg/mL. Of 22 deaths during follow-up, 50% had a TRV≥3.0 m/sec. At 24 months the cumulative survival was 83% with TRV≥3.0 m/sec and 98% with TRV47 years, male gender, chronic transfusions, WHO class III-IV, increased hemolytic markers, ferritin and creatinine were also associated with increased risk of death. Conclusions: A TRV≥ 3.0 m/sec occurs in approximately 10% of individuals and has the highest risk for death of any measured variable. The study is registered in ClinicalTrials.gov with identifier: NCT00492531

    Neural circuits for the adaptive regulation of fear and extinction memory

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    The regulation of fear memories is critical for adaptive behaviors and dysregulation of these processes is implicated in trauma- and stress-related disorders. Treatments for these disorders include pharmacological interventions as well as exposure-based therapies, which rely upon extinction learning. Considerable attention has been directed toward elucidating the neural mechanisms underlying fear and extinction learning. In this review, we will discuss historic discoveries and emerging evidence on the neural mechanisms of the adaptive regulation of fear and extinction memories. We will focus on neural circuits regulating the acquisition and extinction of Pavlovian fear conditioning in rodent models, particularly the role of the medial prefrontal cortex and hippocampus in the contextual control of extinguished fear memories. We will also consider new work revealing an important role for the thalamic nucleus reuniens in the modulation of prefrontal-hippocampal interactions in extinction learning and memory. Finally, we will explore the effects of stress on this circuit and the clinical implications of these findings

    Efficacy of AZM therapy in patients with gingival overgrowth induced by Cyclosporine A: a systematic review

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    <p>Abstract</p> <p>Background</p> <p>In daily clinical practice of a dental department it's common to find gingival overgrowth (GO) in periodontal patients under treatment with Cyclosporine A (CsA). The pathogenesis of GO and the mechanism of action of Azithromycin (AZM) are unclear. A systematic review was conducted in order to evaluate the efficacy of Azithromycin in patients with gingival overgrowth induced by assumption of Cyclosporine A.</p> <p>Methods</p> <p>A bibliographic search was performed using the online databases MEDLINE, EMBASE and Cochrane Central of Register Controlled Trials (CENTRAL) in the time period between 1966 and September 2008.</p> <p>Results</p> <p>The literature search retrieved 24 articles; only 5 were Randomised Controlled Trials (RCTs), published in English, fulfilled the inclusion criteria. A great heterogeneity between proposed treatments and outcomes was found, and this did not allow to conduct a quantitative meta-analysis. The systematic review revealed that a 5-day course of Azithromycin with Scaling and Root Planing reduces the degree of gingival overgrowth, while a 7-day course of metronidazole is only effective on concomitant bacterial over-infection.</p> <p>Conclusion</p> <p>Few RCTs on the efficacy of systemic antibiotic therapy in case of GO were found in the literature review. A systemic antibiotic therapy without plaque and calculus removal is not able to reduce gingival overgrowth. The great heterogeneity of diagnostic data and outcomes is due to the lack of precise diagnostic methods and protocols about GO. Future studies need to improve both diagnostic methods and tools and adequate classification aimed to determine a correct prognosis and an appropriate therapy for gingival overgrowth.</p

    Medication safety in community pharmacy: a qualitative study of the sociotechnical context

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    <p>Abstract</p> <p>Background</p> <p>While much research has been conducted on medication safety, few of these studies have addressed primary care, despite the high volume of prescribing and dispensing of medicines that occurs in this setting. Those studies that have examined primary care dispensing emphasised the need to understand the role of sociotechnical factors (that is, the interactions between people, tasks, equipment and organisational structures) in promoting or preventing medication incidents. The aim of this study was to identify sociotechnical factors that community pharmacy staff encounter in practice, and suggest how these factors might impact on medication safety.</p> <p>Methods</p> <p>Sixty-seven practitioners, working in the North West of England, took part in ten focus groups on risk management in community pharmacy. The data obtained from these groups was subjected to a qualitative analysis to identify recurrent themes pertaining to sociotechnical aspects of medication safety.</p> <p>Results</p> <p>The findings indicated several characteristics of participants' work settings that were potentially related to medication safety. These were broadly classified as relationships involving the pharmacist, demands on the pharmacist and management and governance of pharmacists.</p> <p>Conclusion</p> <p>It is recommended that the issues raised in this study be considered in future work examining medication safety in primary care.</p
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