2,627 research outputs found
Application of survival analysis and multistate modeling to understand animal behavior: examples from guide dogs
Epidemiology is the study of patterns of health-related states or events in populations. Statistical models developed for epidemiology could be usefully applied to behavioral states or events. The aim of this study is to present the application of epidemiological statistics to understand animal behavior where discrete outcomes are of interest, using data from guide dogs to illustrate. Specifically, survival analysis and multistate modeling are applied to data on guide dogs comparing dogs that completed training and qualified as a guide dog, to those that were withdrawn from the training program. Survival analysis allows the time to (or between) a binary event(s) and the probability of the event occurring at or beyond a specified time point. Survival analysis, using a Cox proportional hazards model, was used to examine the time taken to withdraw a dog from training. Sex, breed, and other factors affected time to withdrawal. Bitches were withdrawn faster than dogs, Labradors were withdrawn faster, and Labrador × Golden Retrievers slower, than Golden Retriever × Labradors; and dogs not bred by Guide Dogs were withdrawn faster than those bred by Guide Dogs. Multistate modeling (MSM) can be used as an extension of survival analysis to incorporate more than two discrete events or states. Multistate models were used to investigate transitions between states of training to qualification as a guide dog or behavioral withdrawal, and from qualification as a guide dog to behavioral withdrawal. Sex, breed (with purebred Labradors and Golden retrievers differing from F1 crosses), and bred by Guide Dogs or not, effected movements between states. We postulate that survival analysis and MSM could be applied to a wide range of behavioral data and key examples are provided
Impact of treatment strategies on cephalosporin and tetracycline resistance gene quantities in the bovine fecal metagenome
The study objective was to determine the effects of two treatment regimens on quantities of ceftiofur and tetracycline resistance genes in feedlot cattle. The two regimens were ceftiofur crystalline-free acid (CCFA) administered to either one or all steers within a pen and subsequent feeding/not feeding of therapeutic doses of chlortetracycline. A 26-day randomized controlled field trial was conducted on 176 steers. Real-time PCR was used to quantify bla[subscript CMY-2], bla[subscript CTX-M], tet(A), tet(B), and 16S rRNA gene copies/gram of feces from community DNA. A significant increase in ceftiofur resistance and a decrease in tetracycline resistance elements were observed among the treatment groups in which all steers received CCFA treatment, expressed as gene copies/gram of feces. Subsequent chlortetracycline administration led to rapid expansion of both ceftiofur and tetracycline resistance gene copies/gram of feces. Our data suggest that chlortetracycline is contraindicated when attempting to avoid expansion of resistance to critically important third-generation cephalosporins
Reformulating PTSD for DSM-V : Life after Criterion A
The diagnosis of posttraumatic stress disorder has been criticized on numerous grounds, but principally for three reasons (a) the alleged pathologizing of normal events, (b) the inadequacy of Criterion A, and (c) symptom overlap with other disorders. The authors review these problems along with arguments why the diagnosis is nevertheless worth retaining in an amended form. A proposal for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders ( DSM-V ) is put forward that involves abolishing Criterion A, narrowing the B criteria to focus on the core phenomena of flashbacks and nightmares, and narrowing the C and D criteria to reduce overlap with other disorders. The potential advantages and disadvantages of this formulation are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64303/1/20443_ftp.pd
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A three-regime model of speculative behaviour: modelling the evolution of the S&P 500 composite index
We examine whether a three-regime model that allows for dormant, explosive and collapsing speculative behaviour can explain the dynamics of the S&P 500. We extend existing models of speculative behaviour by including a third regime that allows a bubble to grow at a steady rate, and propose abnormal volume as an indicator of the probable time of bubble collapse. We also examine the financial usefulness of the three-regime model by studying a trading rule formed using inferences from it, whose use leads to higher Sharpe ratios and end of period wealth than from employing existing models or a buy-and-hold strategy
The Good Samaritan and the Marketer: public perceptions of humanitarian and international development NGOs
This article reports on a nationwide study investigating public responses to humanitarian communications. Based on focus group data with members of the UK public, the paper discusses two key models through which NGOs identities and activities are understood and judged, both positively and negatively: the Good Samaritan and the Marketer. Thematic analysis of the focus groups extracts exposes the salience of these models in people's thinking, how they speak to each other and how they inform and affect the relationship between NGOs and public. The paper discusses the themes in relation to current debates on organisations' image and trust and confidence in nonprofit organisations and humanitarian NGOs. The data show deep public disillusionment and disappointment deriving from the recognition of the Marketer model being applied to and employed within the realm of humanitarianism. This suggests that NGOs' moving away from traditional notions of charity might be counterproductive and in the long-term risky
Insights into mantle composition and mantle melting beneath mid-ocean ridges from postspreading volcanism on the fossil Galapagos Rise
New major and trace element and Sr, Nd, and Pb isotope data, together with 39Ar-40Ar ages for lavas from the extinct Galapagos Rise spreading center in the eastern Pacific reveal the evolution in magma compositions erupted during slowdown and after the end of active spreading at a mid-ocean ridge. Lavas erupted at 9.2 Ma, immediately prior to the end of spreading are incompatible element depleted mid-ocean ridge tholeiitic basalts, whereas progressively younger (7.5 to 5.7 Ma) postspreading lavas are increasingly alkalic, have higher concentrations of incompatible elements, higher La/Yb, K/Ti, 87Sr/86Sr, and lower 143Nd/144Nd ratios and were produced by smaller degrees of mantle melting. The large, correlated variations in trace element and isotope compositions can only be explained by melting of heterogenous mantle, in which incompatible trace element enriched lithologies preferentially contribute to smaller degree mantle melts. The effects of variable degrees of melting of heterogeneous mantle on lava compositions must be taken into account when using mid-ocean ridge basalt (MORB) to infer the conditions of melting beneath active spreading ridges. For example, the stronger “garnet signature” inferred from Sm/Nd and 143Nd/144Nd ratios for postspreading lavas from the Galapagos Rise results from a larger contribution from enriched lithologies with high La/Yb and Sm/Yb, rather than from a greater proportion of melting in the stability field of garnet peridotite. Correlations between ridge depth and Sm/Yb and fractionation-corrected Na concentrations in MORB worldwide could result from variations in mantle fertility and/or variations in the average degree of melting, rather than from large variations in mantle temperature. If more fertile mantle lithologies are preferentially melted beneath active spreading ridges, then the upper mantle may be significantly more “depleted” than is generally inferred from the compositions of MORB
The quality of volatility traded on the over-the-counter currency market: A multiple horizons study
Previous studies of the quality of market-forecasted volatility have used the volatility that is impliedby exchange-traded option prices. The use of implied volatility in estimating the market view of futurevolatility has suffered from variable measurement errors, such as the non-synchronization of option andunderlying asset prices, the expiration-day effect, and the volatility smile effect. This study circumventsthese problems by using the quoted implied volatility from the over-the-counter (OTC)currency option market, in which traders quote prices in terms of volatility. Furthermore, the OTC currencyoptions have daily quotes for standard maturities, which allows the study to look at the market's ability toforecast future volatility for different horizons. The study finds that quoted implied volatility subsumes theinformation content of historically based forecasts at shorter horizons, and the former is as good as the latterat longer horizons. These results are consistent with the argument that measurement errors have a substantialeffect on the implied volatility estimator and the quality of the inferences that are based on it. © 2003Wiley Periodicals, Inc. Jrl Fut Mark 23:261–285, 2003Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34766/1/10066_ftp.pd
‘Re-reading Raphael Samuel: Politics, Personality and Performance’
For British historian Raphael Samuel, history and politics were inextricable. Best known as the founder of the history workshop movement, the controversial historian took his stance on the democratisation of history-making, becoming an outspoken advocate for public history. Despite making a significant contribution to contemporary historiography, he remains a neglected, even disparaged, figure. This paper contends that the most significant aspect of Samuel’s historical work was not one or other theory of history or argument about the past but his entire way of being an historian. Samuel embodied as much as expressed his ideas, consciously using his personality as a powerful political tool. It is further argued that conventional approaches to intellectual history, focusing on textual outputs, do not fully recognise the significance of performative modes of thinking. Theoretical approaches to performance as identity offer important insight here but can be too schematic in their view of applied and enacted thought. A biographical approach, by contrast, provides the intimate perspective necessary to fully appreciate the fluidity and complexity of such a personality. The paper first situates Samuel in the context of his earlier life, focusing on how and why he created such a public persona and how he adapted it in response to changing circumstances. It then considers the implications and effectiveness of this persona by assessing how it was perceived and narrated by others, acknowledging, in the process, why different groups engaged with and interpreted it differently
Role of the AP2 β-Appendage Hub in Recruiting Partners for Clathrin-Coated Vesicle Assembly
Adaptor protein complex 2 α and β-appendage domains act as hubs for the assembly of accessory protein networks involved in clathrin-coated vesicle formation. We identify a large repertoire of β-appendage interactors by mass spectrometry. These interact with two distinct ligand interaction sites on the β-appendage (the “top” and “side” sites) that bind motifs distinct from those previously identified on the α-appendage. We solved the structure of the β-appendage with a peptide from the accessory protein Eps15 bound to the side site and with a peptide from the accessory cargo adaptor β-arrestin bound to the top site. We show that accessory proteins can bind simultaneously to multiple appendages, allowing these to cooperate in enhancing ligand avidities that appear to be irreversible in vitro. We now propose that clathrin, which interacts with the β-appendage, achieves ligand displacement in vivo by self-polymerisation as the coated pit matures. This changes the interaction environment from liquid-phase, affinity-driven interactions, to interactions driven by solid-phase stability (“matricity”). Accessory proteins that interact solely with the appendages are thereby displaced to areas of the coated pit where clathrin has not yet polymerised. However, proteins such as β-arrestin (non-visual arrestin) and autosomal recessive hypercholesterolemia protein, which have direct clathrin interactions, will remain in the coated pits with their interacting receptors
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Spirit, mind and body: the archaeology of monastic healing
Archaeology and material culture are used in this chapter to consider how monastic experience responded to illness, ageing and disability. The approach taken is influenced by the material study of religion, which interrogates how bodies and things engage to construct the sensory experience of religion, and by practice-based approaches in archaeology, which examine the active role of space and material culture in shaping religious agency and embodiment. The archaeology of monastic healing focuses on the full spectrum of healing technologies, from managing the body in order to prevent illness, through to the treatment of the sick and preparation of the corpse for burial
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