6,553 research outputs found

    Flexible arms provide constant force for pressure switch calibration

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    In-place calibration of a pressure switch is provided by a system of radially oriented flexing arms which, when rotated at a known velocity, convert the centrifugal force of the arms to a linear force along the shaft. The linear force, when applied to a pressure switch diaphragm, can then be calculated

    Costs and benefits of competitive traits in females: aggression, maternal care and reproductive success

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    Recent research has shown that female expression of competitive traits can be advantageous, providing greater access to limited reproductive resources. In males increased competitive trait expression often comes at a cost, e.g. trading off with parental effort. However, it is currently unclear whether, and to what extent, females also face such tradeoffs, whether the costs associated with that tradeoff overwhelm the potential benefits of resource acquisition, and how environmental factors might alter those relationships. To address this gap, we examine the relationships between aggression, maternal effort, offspring quality and reproductive success in a common songbird, the dark-eyed junco (Junco hyemalis), over two breeding seasons. We found that compared to less aggressive females, more aggressive females spent less time brooding nestlings, but fed nestlings more frequently. In the year with better breeding conditions, more aggressive females produced smaller eggs and lighter hatchlings, but in the year with poorer breeding conditions they produced larger eggs and achieved greater nest success. There was no relationship between aggression and nestling mass after hatch day in either year. These findings suggest that though females appear to tradeoff competitive ability with some forms of maternal care, the costs may be less than previously thought. Further, the observed year effects suggest that costs and benefits vary according to environmental variables, which may help to account for variation in the level of trait expression.Research was supported by National Science Foundation (NSF) grants to EK (BSC 05-19211 and IOS 08-20055) and an NSF Doctoral Dissertation Improvement Grant to KC (09-10036). KC was also supported by NSF Graduate Research Fellowship (www.nsfgrfp.org)

    Cumulative prospect theory and gambling

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    Whilst Cumulative Prospect theory (CPT) provides an explanation of gambling on longshots at actuarially unfair odds, it cannot explain why people might bet on more favoured outcomes. This paper shows that this is explicable if the degree of loss aversion experienced by the agent is reduced for small-stake gambles (as a proportion of wealth), and probability distortions are greater over losses than gains. If the utility or value function is assumed to be bounded, the degree of loss aversion assumed by Kahneman and Tversky leads to absurd predictions, reminiscent of those pointed out by Rabin (2000), of refusal to accept infinite gain bets at low probabilities. Boundedness of the value function in CPT implies that the indifference curve between expected-return and win-probability will typically exhibit both an asymptote (implying rejection of an infinite gain bet) and a minimum at low probabilities, as the shape of the value function dominates the probability weighting function. Also the high probability section of the indifference curve will exhibit a maximum. These implications are consistent with outcomes observed in gambling markets.

    Do Fairness Opinion Valuations Contain Useful Information?

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    We analyze target firm valuations disclosed in the fairness opinions of negotiated mergers between 1998 and 2005. On average, acquirer advisors exhibit a greater degree of valuation optimism than do target advisors. Top-tier advisors produce more accurate valuations than lower-tier advisors, but valuation accuracy is unrelated to the contingency structure of advisory fees. The stock price reactions to merger announcements and to the public disclosure of fairness opinions are positively related to the difference between target firm valuations contained in the fairness opinion and the merger offer price. We conclude that fairness opinions contain information not previously available to market participants.

    A compilation of magnetic observatories

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    Magnetic observatories for use during international quiet sun year /iqsy

    Short and long distance translocations: Movement and survival in eastern box turtles (_Terrapene carolina carolina_)

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    *Background/Question/Methods*

Human development represents a serious threat to wildlife populations through continued habitat loss and incidental mortality from construction activities. Resource managers responsible for protecting species with legal status or high public profile are faced with difficult decisions on how to best manage populations located in construction zones. One approach to mitigate mortalities is to relocate individuals. The effectiveness of translocation for reptiles and amphibians has been questioned, with studies often reporting higher mortality and increased movements of translocated individuals. Translocations of reptiles and amphibians have primarily involved moving animals long distances, well beyond an individual’s home range. For reptiles this means finding new nesting, foraging, and overwintering sites, which may be problematic. Moving individuals only short distances, within their home range, may reduce those problems. As part of the mitigation plan for a highway construction project in central Maryland, groups of eastern box turtles (Terrapene carolina carolina) were translocated both short distances (<0.5km), and long distances (~5km). To investigate differences in survival and movement patterns among long distance translocation, short distance translocation, and non-translocation groups, I tracked 94 turtles (31 long distance translocation, 29 short distance translocation, and 34 non-translocation) using radio telemetry. 

*Results/Conclusions*

Eleven animals died during the first activity season after translocation (April through November 2008). The mortalities included two long distance translocation, six short distance translocation, and three non-translocation animals. The causes of mortality included road kill, construction activity, and unknown (1, 4, and 6 mortalities respectively). All construction related mortalities were a result inadequate exclusion fencing to keep turtles from trespassing back onto the construction site. All mortalities due to construction were either non-translocation or short distance translocation animals. Eleven other individuals were located at least once within the construction zone, suggesting that without our intervention mortality rates would have been much higher. Preliminary results for movement show that turtles in the non-translocation group had the lowest average movements while long distance translocation animals had the greatest average movements. Long distance translocation turtles also chose overwintering sites farther away from their initial overwintering sites than either short distance translocation or non-translocation turtles (average distance from original site of 261.8m, 155.6m, and 124.3m respectively). This suggests that movement patterns of short distance translocation turtles are more like native turtles.
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    Evaluative Research and Nutrition Programs for the Elderly

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    This report looks at the means to evaluate the Nutrition Act, Title VII-Nutrition Program for the Elderly, (Public Law No. 258, 1972)

    Age Distinctions and Their Social Functions: A Critique of the Age Discrimination Act of 1975

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    Characterization of the Role of R7-RGS Proteins in Mammalian Retina and Vision

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    ABSTRACT OF THE DISSERTATION Characterization of the Role of RGS7-family Proteins in Mammalian Retina and Vision by Matthew David Cain Doctor of Philosophy in Biology and Biomedical Sciences Molecular Cell Biology Washington University in St. Louis, 2014 Professor Kendall J. Blumer, Chairperson GPCR/G protein signaling is a critical component of neuronal signal transduction and function. G protein signaling is regulated by a family of regulator of G protein signaling (RGS) proteins that act as GTPase activating proteins (GAPs) for GÎą subunits. In the retina, the R7-RGS family of RGS proteins which specifically act as GAPs toward Gi/o, are critical regulators of phototransduction and ON bipolar cell light responses in the outer retina. While R7-RGS proteins are expressed throughout the inner retina, their function there is unknown. The goal of this dissertation project is to characterize R7-RGS regulation on retina function and vision. This dissertation is divided into four parts: i) analysis of inner retinal function in mature and developing R7BP-/- retinas, ii) characterization of composition and localization of R7-RGS/R7BP complexes in the dorsal lateral geniculate nucleus (dLGN), iii) characterization of blockade of RGS regulation of Gi2 and Go subunits on outer retina function, and iv) preliminary analysis of the effect of RGS6 ablation on vision. In part i), we found that R7BP is expressed in starburst amacrine cells (SAC) and retinal ganglion cells (RGC). R7BP regulates mesopic RGC light responses and glutamatergic wave burst duration in mature and developing retina, respectively. In part ii), we found that R7PB is expressed in the dLGN. R7BP interacts with RGS6 and RGS7 in lateral geniculate nucleus lysates, but is not necessary for their membrane localization. In part iii), outer retinal phenotypes of RGS-insensitive Gi2 and Go mutant mice were characterized. RGS regulation of Gi2 is necessary for normal rod light responses. Heterozygous expression of RGS-insensitive Go subunits was not sufficient to perturb ON bipolar cell light responses or dendritic morphology. In part iv), we found that RGS6 is expressed in starburst amacrine cells. RGS6 localization to SAC plexi is independent of R7BP. We demonstrated that, although dispensable for normal phototransduction or ON bipolar light responses, RGS6 is necessary for normal spatial vision. Based on these findings, we suggest that RGS regulation of Gi/o signaling is necessary for normal retinal function and that R7-RGS proteins regulate inner retinal function. Additionally, we identified several new candidate circuits to further explore R7-RGS function in the visual system

    Shirking in the National Hockey League

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    Shirking has been examined in baseball and basketball, but never hockey. If Shirking is found to be evident in hockey, then management should give players shorter contracts and should pay a discount price if a long‐term contract is given. The dependent variable for this study is shirking. There are many different independent variables and they are all different measures of performance (except for dummy variables for team and position). Most studies of hockey have minimal measures of performance, which are usually offensive statistics, but I will include defensive statistics as well. The sample for the study is players who participated in the 2007‐08 and 2008‐09 NHL seasons. These players also had to be under a contract that saw them make more than $500,000 during the 2008‐09 campaign. The salary data was compiled from NHLnumbers.com while the statistical data was taken from NHL.com. I am running a five stage regression analysis to test my shirking hypothesis. One possible measurement problem is that there is only data from two seasons, but there are still over 550 players tested. Shirking was not found in the NHL. The more years remaining on a player’s contract does not decrease performance. However, a player’s performance decreases as their likelihood of retirement at the end of their current contract increases. I will refer to the former traditional shirking because that is what most of the literature examines when testing for shirking. I will refer to the latter as non‐traditional shirking
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