5,671 research outputs found
RXTE and BeppoSAX Observations of MCG -5-23-16: Reflection From Distant Cold Material
We examine the spectral variability of the Seyfert 1.9 galaxy MCG -5-23-16
using RXTE and BeppoSAX observations spanning 2 years from April 1996 to April
1998. During the first year the X-ray source brightens by a factor of ~25% on
timescales of days to months. During this time, the reprocessed continuum
emission seen with RXTE does not respond measurably to the continuum increase.
However, by the end of the second year during the BeppoSAX epoch the X-ray
source has faded again. This time, the reprocessed emission has also faded,
indicating that the reprocessed flux has responded to the continuum. If these
effects are caused by time delays due to the distance between the X-ray source
and the reprocessing region, we derive a light crossing time of between ~1
light day and ~1.5 light years. This corresponds to a distance of 0.001 pc to
0.55 pc, which implies that the reprocessed emission originates between 3x10^15
cm and 1.6x10^18 cm from the X-ray source. In other words, the reprocessing in
MCG -5-23-16 is not dominated by the inner regions of a standard accretion
disk.Comment: Accepted for publication in ApJ. 17 pages, 8 figure
Undergraduate Library Internships and Professional Success
This poster reports on an assessment completed of former undergraduate library interns to explore the impact their internship had on the development of career goals, acceptance to and preparation for graduate education, and their early career. Through an online survey (n= 45) and six semi-structured telephone interviews, respondents reported a positive impact on the above areas
Undergraduate Library Internships at Musselman Library, Gettysburg College
In 2015-2016, Musselman Library at Gettysburg College participated in Cohort 3 of the Association of College and Research Librariesâ Assessment in Action program. This report outlines an assessment completed of former undergraduate library interns in order to explore the impact their internship experience had on the development of career goals, acceptance to and preparation for graduate education, and their early career. Through an online survey (n= 45) and six semi-structured telephone interviews, respondents reported a positive impact on the above areas
Video Game Cultivation: Sowing the Seeds of Consumer Behavior
George Gerbner (1998) dedicated a significant amount of this life attempting to understand the creation and impact of mass media messages on viewers. Out of this research sprang cultivation theory, which holds viewers\u27 realities can be impacted over time by the media environment they inhabit and its overarching messages. While often applied to television, cultivation theory has largely ignored other mediums, specifically video games. Video games have evolved as a medium since the public arcades of the 1980\u27s and now run on high-powered, internet-enabled consoles. These consoles allow producers into the home of the consumer, saturating them with messages. This thesis advocates video game producer messages are encoded in such a manner as to encourage the consumption of video game content and instill in the consumer a reality constructed by the producer. To interrogate these messages, I conduct a case study of a video game developer, Tacit Games (a pseudonym), and examine how the producer attempts to cultivate consumption in the consumer through approaches like downloadable content and framing the video game experience for the video game consumer. Specifically, I examine messages surrounding the developer\u27s franchise, City Mayhem (also a pseudonym). To do this, I conduct qualitative interviews with five senior employees of the company to ascertain what messages are produced for the consumer in relation to the goals of this thesis. The data collected from these interviews is analyzed through the lens of cultural Marxism, which entails the examination of the limitations and pressures exerted on the formation of culture
Improving Swimming Economy of Novice, Adult, Female Swimmers by Training on a VĂ€sa Swim Trainer
The purpose of this study was to determine if the swimming economy of novice, adult, female swimmers can be increased by training on a VĂ€sa Swim Trainer. Economy of swimming was defined as either: 1) decreased submaximal oxygen consumption (VO2); 2) decreased oxygen consumption per given distance (VO2/d); 3) decrease ratio of arm stroke cycles per given distance to swimming velocity (ASI); and 4) decrease submaximal heart rate (HR).
Eight females between the age of 35 to 60 years, mean age 50.4, who were considered to be novice swimmers (average 45.7 meter lap time greater than 60 seconds) and had been swimming at least twice a week for three weeks prior to the study, participated in this study. All subjects trained on the VÀsa Swim Trainer three days a week in an attempt to increase upper body strength. In addition the subjects continued swimming weekly, for six weeks. Prior to the training period, subjects were pre-tested by swimming ten laps (457.2 meters) and performing a maximal effort on the swim trainer. Pre-test submaximal VO2, VO2/d, ASI, submaximal HR while swimming, and the vÀsa trainer one repetition maximum (1-RM) were calculated. After six weeks of training submaximal VO2, VO2/d, ASI, submaximal HR, and 1-RM tests were repeated to determine a training effect.
Dependent t-tests were used to determine the significance (p \u3c.01) of the change in means for pre-test and post-test submaximal VO2, VO2/d, ASI, submaximal HR, and 1-RM. After six weeks of training there was a significant increase in 1-RM and a significant decrease in submaximal VO2, VO2/d, and ASI. A non-significant decrease in submaximal heart rate was observed. It was concluded that training on the VĂ€sa Swim Trainer will improve the swimming economy of the novice, adult, female swimmer
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A comparative study of executive decision making in the United States and Ghana.
The research presented here examines core decision making orientations of top executives of small and medium-sized corporations in two national cultures--the United States and Ghana (Africa). The purpose is to understand how these executives arrive at the actions they initiate on behalf of their organizations; whether the approaches differ significantly, and, if they do, in what ways. The study adopts a behavioral approach and is undergirded by the proposition that executives, when faced with a decision problem, have preferences for particular types of decision procedures. The study deals directly with individual and group differences among executive decision makers. Two human information processing (HIP) metaphors--rational and intuition--are used to develop a number of hypotheses. Data were gathered through a questionnaire survey instrument adapted from the Taggart & Valenzi (1990) HIP survey, and from the works of Heller & Wilpert (1981) and Hofstede (1980). Questionnaires were mailed to three hundred and twenty U.S. executives. Thirty-one percent of the executives completed and returned the survey instrument. One hundred and eighty Ghanaian executives were personally contacted in eight cities with the survey instrument. The response rate among these executives was forty two percent. Survey questionnaires were analyzed using analysis of variance procedures on the rational and intuitive index scores. T-tests were conducted on the decision centralization scores . The results suggest that there were differences in the decision making orientation of United States and Ghanaian executives with regard to the rational metaphor. The differences were, however, not in the direction predicted. Executive respondents in Ghana, more than executives in the United States, appeared to have greater orientation to decision information processing using logic, planning and ritual. No significant differences were found in relation to executives\u27 orientation to the intuitive metaphor in the two countries. As was suggested in the literature, executives in Ghana preferred more centralized decision making than executives in the U.S. There was evidence of association between decision centralization and the intuitive mode. The implications of the results of the study are that the biocomputer functions of the executive brain are already in action in practice, and research and theory building must provide clarifications equally for the two modes of executive thinking. Secondly, decision information processing (using the rational and intuition metaphors) appears to be influenced less by culture-specific decision approaches than by culture-general organization perspectives. Third, the study should also be interpreted as a learning process in the transferability of western-based concepts and methodologies to other cultures, such as Ghana (Adler, et al., 1989:67)
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Bioaccumulation of PCB & DDE methyl sulfones in marine mammals and their interactions with receptor proteins
PCB and DDE-Methyl sulphone metabolites are the product of enzymatic and bile acid entero hepatic metabolism in the final phase (III) of PCB and DDE detoxification in mammals following hepatic microsomal cytochrome P450-dependent metabolism (phase I) and conjugation (phase II). There is good evidence that PCB and DDE methyl sulphone (MSF) metabolites interfere with steroid binding to a receptor protein in uterine epithelium (uteroglobin - UG2 and bronchial epithelium (clara cell secretory protein - CCSP). UG and CCSP are homologous 16,000 Da proteins with different tissue-specific functions. UG binds progesterone in the pre-implantation uterus to signal localised endometrial thickening and capillary formation, vital for successful attachment of the fertilised embryo. PCB-MSFs can displace progesterone in the mammalian uterus due to their higher affinity for UG, resulting in implantation failure or early fetal death. CCSP however, functions to sequester phospholipase A2 (PLA2) released in response to stress (pathogenic infection / injury) to suppress inflammatory responses triggered by PLA2 in bronchial epithelium. CCSP is also known as retinol-binding protein (RBP) transporting retinol (vit A) to target epithelia for a functional immune response*. Studies with Harbour Seals demonstrated displacement of retinol from RBP by hydroxy-PCB metabolites resulting in immunosuppression. PCB-MSFs have been shown to accumulate in clara cells and uterine epithelium in laboratory radioactive tracer studies and CCSP-knock out studies with mice. PCB and DDE -MSFs burdens have been found in marine mammals, suggesting they may be subject to reproductive and immuno-toxic effects of these metabolites. This study determines PCB and DDE-MSFs burdens in tissues (including lung & uterus) of Harbour Seal (Phoca vitulina) and Striped Dolphin (Stenella coeruleoalba) morbillivirus victims and characterises the marine mammalian UG/CCSP protein
Thermal expansion method for lining tantalum alloy tubing with tungsten
A differential-thermal expansion method was developed to line T-111 (tantalum - 8 percent tungsten - 2 percent hafnium) tubing with a tungsten diffusion barrier as part of a fuel element fabrication study for a space power nuclear reactor concept. This method uses a steel mandrel, which has a larger thermal expansion than T-111, to force the tungsten against the inside of the T-111 tube. Variables investigated include lining temperature, initial assembly gas size, and tube length. Linear integrity increased with increasing lining temperature and decreasing gap size. The method should have more general applicability where cylinders must be lined with a thin layer of a second material
Debris cover and surface melt at a temperate maritime alpine glacier: Franz Josef Glacier, New Zealand
Melt rates on glaciers are strongly influenced by the presence of supraglacial debris, which can either enhance or reduce ablation relative to bare ice. Most recently, Franz Josef Glacier has entered into a phase of strong retreat and downwasting, with the increasing emergence of debris on the surface in the ablation zone. Previously at Franz Josef Glacier, melt has only been measured on bare ice. During February 2012, a network of 11 ablation stakes was drilled into locations of varying supraglacial debris thickness on the lower glacier. Mean ablation rates over 9 days varied over the range 1.2â10.1 cm dâ1, and were closely related to debris thickness. Concomitant observations of air temperature allowed the application of a degree-day approach to the calculation of melt rates, with air temperature providing a strong indicator of melt. Degree-day factors (d f) varied over the range 1.1â8.1 mm dâ1 °Câ1 (mean of 4.4 mm dâ1 °Câ1), comparable with rates reported in other studies. Mapping of the current debris cover revealed 0.7 km2 of the 4.9 km2 ablation zone surface was debris-covered, with thicknesses ranging 1â50 cm. Based on measured debris thicknesses and d f, ablation on debris-covered areas of the glacier is reduced by a total of 41% which equates to a 6% reduction in melt overall across the entire ablation zone. This study highlights the usefulness of a short-term survey to gather representative ablation data, consistent with numerous overseas ablation studies on debris-covered glaciers
Atypical hemolytic uremic syndrome in the postpartum period: a case series
Background: Atypical hemolytic uremic syndrome (aHUS) may present in either the antepartum or postpartum period and is often indistinguishable from other pregnancy-associated diseases. Timely recognition and appropriate treatment can greatly reduce maternal morbidity and mortality.
Cases: This case series describes two cases of aHUS in the post-partum period, the difficulty in distinguishing the diagnosis, and the implementation of appropriate treatment with eculizumab, a terminal complement inhibitor.
Conclusion: As a terminal complement inhibitor, eculizumab, has been shown to significantly improve clinical and long term renal outcomes, early diagnosis of aHUS is increasingly important. These two cases of aHUS demonstrate the path of accurate diagnosis and timely initiation of therapy to maximize the possibility of patient recovery
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