4,937 research outputs found

    German Perceptions of Poland and Russia in the Early Modern Period

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    This thesis examines the views of Germans on the people and institutions of Russia and the Polish-Lithuanian Commonwealth in the Early Modern period. While German opinions of Eastern Europe in the nineteenth and early twentieth centuries have been well researched, there is a gap in the historiography for the sixteenth to eighteenth centuries. German perceptions of the Polish-Lithuanian Commonwealth and Russia ranged from those who stereotyped the East as a backward, uncivilized place to be dominated or changed to those who appreciated and celebrated various aspects of Polish or Russian culture. By analyzing the views of German intellectuals, travelers, rulers and others on Russia and the Polish-Lithuanian Commonwealth, it is possible to understand the complex nature of Early Modern German views of the East before they were influenced by biologically-based racism and ethnic nationalism

    A flight investigation of performance and loads for a helicopter with NLR-1T main-rotor blade sections

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    Data on performance and rotor loads for a teetering-rotor, AH-1G helicopter flown with a main rotor that had the NLR-1T airfoil as the blade-section contour are presented. The test envelope included hover, forward-flight speed sweeps from 35 to 85 m/sec, and collective-fixed maneuvers at about 0.25 tip-speed ratio. The data set for each test point described vehicle flight state, control positions, rotor loads, power requirements, and blade motions. Rotor loads are reviewed primarily in terms of peak-to-peak and harmonic content. Lower frequency components predominated for most loads and generally increased with increased airspeed, but not necessarily with increased maneuver load factor

    A flight investigation of blade section aerodynamics for a helicopter main rotor having NLR-1T airfoil sections

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    A flight investigation was conducted using a teetering-rotor AH-1G helicopter to obtain data on the aerodynamic behavior of main-rotor blades with the NLR-1T blade section. The data system recorded blade-section aerodynamic pressures at 90 percent rotor radius as well as vehicle flight state, performance, and loads. The test envelope included hover, forward flight, and collective-fixed maneuvers. Data were obtained on apparent blade-vortex interactions, negative lift on the advancing blade in high-speed flight and wake interactions in hover. In many cases, good agreement was achieved between chordwise pressure distributions predicted by airfoil theory and flight data with no apparent indications of blade-vortex interactions

    A flight investigation of performance and loads for a helicopter with RC-SC2 main-rotor blade sections

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    The test envelope included hover, forward-flight speed sweeps from 33 to 74 m/sec (65 to 144 knots), and collective-fixed maneuvers at about 0.25 tip-speed ratio. The data set for each test point describes vehicle flight states, control positions, rotor loads, power requirements and blade motions. Rotor loads were reviewed primarily in terms of peak-to-peak and harmonic content. Lower frequency components predominated for most loads and generally increased with increased airspeed, but not necessarily with increased maneuver load factor

    First results of material charging in the space environment

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    A satellite experiment, designed to measure potential charging of typical thermal control materials at near geosynchronous altitude, was flown as part of the SCATHA program. Direct observations of charging of typical satellite materials in a natural charging event ( 5 keV) are presented. The results show some features which differ significantly from previous laboratory simulations of the environment

    Ecological and geographical speciation in Lucilia bufonivora: The evolution of amphibian obligate parasitism

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    This is the final version. Available on open access from Elsevier via the DOI in this record. Lucilia (Diptera: Calliphoridae) is a genus of blowflies comprised largely of saprophagous and facultative parasites of livestock. Lucilia bufonivora, however, exhibits a unique form of obligate parasitism of amphibians, typically affecting wild hosts. The evolutionary route by which amphibian myiasis arose, however, is not well understood due to the low phylogenetic resolution in existing nuclear DNA phylogenies. Furthermore, the timing of when specificity for amphibian hosts arose in L. bufonivora is also unknown. In addition, this species was recently reported for the first time in North America (Canada) and, to date, no molecular studies have analysed the evolutionary relationships between individuals from Eastern and Western hemispheres. To provide broader insights into the evolution of the amphibian parasitic life history trait and to estimate when the trait first arose, a time-scaled phylogeny was inferred from a concatenated data set comprising mtDNA, nDNA and non-coding rDNA (COX1, per and ITS2 respectively). Specimens from Canada, the UK, Poland, Switzerland, the Netherlands and Germany were analysed, as well as individuals from its sister taxa, the saprophage Lucilia silvarum and a Nearctic species also implicated in amphibian myiasis, Lucilia elongata. Obligate amphibian parasitism appears to have arisen ~4 mya, likely as a result of niche displacement of a saprophagous/facultative parasite ancestor. Consistent paraphyly of L. bufonivora with respect to L. elongata across single-gene phylogenies and high mtDNA genetic distances between Nearctic and Palearctic individuals suggest on-going cryptic speciation facilitated by geographical isolation. These findings suggest that recent reports of L. bufonivora in the Nearctic do not constitute a recent introduction, but instead suggest that it remained unrecorded due to taxonomic confusion and low abundance. This is the first study to confirm the involvement of L. bufonivora in amphibian myiasis in Canada using DNA-based identification methods.Consejo Nacional de Ciencia y Tecnología, MexicoPolish National Science Centr

    Critical evaluation of stents in coronary angioplasty: a systematic review

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    This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.Background Coronary stents are routinely placed in the treatment and prophylaxis of coronary artery disease (CAD). Current coronary stent designs are prone to developing blockages: in-stent thrombosis (IST) and in-stent re-stenosis (ISR). This is a systematic review of the design of current coronary stent models, their structural properties and their modes of application, with a focus on their associated risks of IST and ISR. The primary aim of this review is to identify the best stent design features for reducing the risk of IST and ISR. To review the three major types of stents used in clinical settings today, determining best and relevant clinical practice by exploring which types and features of offer improved patient outcomes regarding coronary angioplasty. This information can potentially be used to increase the success rate of coronary angioplasty and stent technology in the future taking into account costs and benefits. Methods Scientific databases were searched to find studies concerning stents. After the exclusion criteria were applied, 19 of the 3192 searched literature were included in this review. Studies investigating three major types of stent design were found: bare-metal stents (BMS), drug-eluting stents (DES) and bioresorbable stents (BRS). The number of participants varied between 14 and 1264. On average 77.4% were male, with a mean age of 64 years. Results From the findings of these studies, it is clear that DES are superior in reducing the risk of ISR when compared to BMS. Conflicting results do not clarify whether BRS are superior to DES at reducing IST occurrence, although studies into newer BRS technologies show reducing events of IST to 0, creating a promising future for BRS showing them to be non-inferior. Thinner stents were shown to reduce IST rates, due to better re-endothelialisation. Scaffold material has also been shown to play a role with cobalt alloy stents reducing the risk of IST. This study found that thinner stents that release drugs were better at preventing re-blockages. Some dissolvable stents might be better at stopping blood clots blocking the arteries when compared to metal stents. The method and procedure of implanting the stent during coronary angioplasty influences success rate of these stents, meaning stent design is not the only significant factor to consider. Conclusions Positive developments in coronary angioplasty could be made by designing new stents that encompass all the most desirable properties of existing stent technology. Further work is needed to investigate the benefits of BRS in reducing the risk of IST compared to DES, as well as to investigate the effects of different scaffold materials on IST and ISR outcomes

    The Effects Of Athletic Identity And Perceptions Of Masculinity On Body Image In Male Collegiate Wrestlers

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    Successful wrestling performance is largely dictated by weight. Some wrestlers engage in rapid weight loss (RWL) to maximize performance at lower weight classes. These methods can negatively affect male body image (BI) and physical health, but the current prevalence of RWL in wrestling is unknown. The present study examined perceptions of masculinity in relation to BI in male collegiate wrestlers. Survey data were collected from active male NCAA wrestlers that completed the 26-Item Eating Attitudes Test, the Multidimensional Body-Self Relations Questionnaire, the Athlete Identity Measurement Scale, the Hoffman Gender Scale, and three open-ended response items. Eating disorder (ED) risk was positively related to appearance self-importance, body weight vigilance and negatively related to BI satisfaction regarding specific body areas. Gender self-acceptance was related to lower BI self-importance. Qualitative data indicates similarities in traits associated with successful wrestlers and the traditional ideal male. The methods wrestlers use to exemplify those traits can negatively affect their eating behaviors and BI self-perception. The information in this study can be used to inform the development of safer weight loss practices and specialized educational programs for ED risk for wrestlers. This study highlights a need for further qualitative analysis of this relationship in collegiate wrestling
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