bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prolonged Clopidogrel Use After Bare Metal and Drug-Eluting Stent Placement
Authors: Faxon David P. , Lawler Elizabeth , Young Melissa , Gaziano Michael , Kinlay Scott 
Published: June 2012

Background—
Current guidelines recommend combining clopidogrel with aspirin for up to 1 year after coronary stenting, but the value of clopidogrel beyond this time is uncertain.

Methods and Results—

We evaluated all patients in the Veterans Administration healthcare system receiving either drug-eluting or bare metal stents from 2002 to 2006. The Veterans Administration National Patient Care and Pharmacy databases were used to extract patient characteristics, duration of clopidogrel use, and outcomes for up to 4 years after the index procedure. We used Cox proportional hazards to estimate hazard ratios for death, myocardial infarction, revascularization, and bleeding from a 12-month landmark after stenting that excluded patients with events within the first 12 months. Of 42 254 patients, 29 175 met the study inclusion criteria. Compared with ≤12 months of clopidogrel, prolonged clopidogrel (>12 months) was associated with a lower adjusted risk of death for both drug-eluting stents (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.61, 0.82;
P
<0.01) and bare metal stents (HR, 0.85; 95% CI, 0.76, 0.96;
P
=0.01) as well as for death and myocardial infarction but was unrelated to stroke or major bleeding. The effect of prolonged clopidogrel on death or myocardial infarction was significantly greater among patients receiving drug-eluting (HR, 0.70; 95% CI, 0.64, 0.84) compared with bare metal stents (HR, 0.88; 95% CI, 0.79, 0.98; interaction
P
=0.024).

Conclusions—
Patients receiving clopidogrel beyond 12 months had a lower risk of death or myocardial infarction compared patients receiving clopidogrel ≤12 months. The risk reduction was greater for drug-eluting stents. These data support longer durations of dual antiplatelet therapy for patients receiving a stent, particularly for those receiving a drug-eluting stent.
Atmosphere Response Time Scales Estimated from AOGCM Experiments
Authors: Olivié D. J. L. , Peters G. P. , Saint-Martin D. 
Published: June 2012

Abstract
The global-mean surface air temperature response of the climate system to a specific radiative forcing shows characteristic time scales. Identifying these time scales and their corresponding amplitudes (climate sensitivity) allows one to approximate the response to arbitrary radiative forcings. The authors estimate these time scales for a set of atmosphere–ocean general circulation models (AOGCMs) based on relatively short integrations of 100–300 yr for some idealized forcings. Two modes can be clearly distinguished but a large spread in time scales and climate sensitivities exists among the AOGCMs. The analysis herein also shows that different factors influence the mode estimates. The value and uncertainty of the smallest time scale estimate is significantly lower when based on step scenarios than gradual scenarios; the uncertainty on the climate sensitivity of the slow mode can only be reduced significantly by performing longer AOGCM simulations; and scenarios with only a monotonically increasing forcing do not easily permit the climate sensitivity and the response time for the slow mode to be disentangled. Finally, climate sensitivities can be estimated more accurately than response times.
On the Use of Emulators with Extreme and Highly Nonlinear Geophysical Simulators
Authors: Tokmakian Robin , Challenor Peter , Andrianakis Yiannis 
Published: June 2012

Abstract
Gaussian process emulators are a powerful tool for understanding complex geophysical simulators, including oceanic and atmospheric general circulation models. Concern has been raised about their ability to emulate complex nonlinear systems. For the first time, using the simple Stommel model, the way in which emulators can reasonably represent the full sampling space of an extreme nonlinear, bimodal system is illustrated. This simple example also shows how an emulator can help to elucidate interactions between parameters. The ideas are further illustrated with a second, more realistic, intermediate complex climate simulator. The paper describes what is meant by an emulator, the methodology of emulators, how emulators can be assessed, and why they are useful. It is shown how simple emulators can be useful to explore the parameter space (initial conditions, process parameters, and boundary conditions) of complex computer simulators, such as ocean and climate general circulation models, even when simulator outcomes contain steps in the response.
Use of Underwater Gliders for Acoustic Data Retrieval from Subsurface Oceanographic Instrumentation and Bidirectional Communication in the Deep Ocean
Authors: Send Uwe , Regier Lloyd , Jones Brent 
Published: June 2012

Abstract
Many fixed oceanographic instruments and observing systems are deployed in the water column or on the seafloor for extended periods of time without any expression at the sea surface. To routinely communicate with such subsurface instruments in the deep ocean, here a system is presented that uses underwater gliders and commercially available acoustic modems for this task and its use is demonstrated with subsurface moorings and inverted echo sounders plus bottom pressure sensor (PIES). One recent glider mission spent 31 days in data retrieval dives, capturing 2 MB of error-free subsurface data. To acquire this volume, a total of 2.65 MB (including all retransmissions) were sent, with a success rate of 75%. A model for the energy usage of each phase of modem function was derived from laboratory measurements. While the model predicts that the glider would expend 0.21 J to acquire each data byte, the actual consumption of the glider in the field is 0.49 J byte−1. The inefficiency is due to overhead associated with establishment of the acoustic link and with the resending of data that is received with errors. Including all the time for negotiating the acoustic link and for the retransmission of erroneous data, the net data throughput are around 3 bytes s−1 in spite of the modem operating at 140 to 600 baud. Even with these limitations, the technique has shown to be useful and is being utilized routinely in a research project in the California Current to obtain data from horizontal distances up to 7 km from an instrument at depths up to 4000 m, transferring on average 6 kB of data in a day of acoustic communications.
A Scale-Aware Anticipated Potential Vorticity Method: On Variable-Resolution Meshes
Authors: Chen Qingshan , Gunzburger Max , Ringler Todd 
Published: June 2012

Abstract
A scale-aware formulation of the anticipated potential vorticity method (APVM), previously derived for quasi-uniform unstructured grids, is evaluated on multiresolution grids. Comparison is made to the original, nonscale-aware formulation of the APVM. Numerical experiments are performed using the shallow-water standard test case 5. The scale awareness of the new formulation is demonstrated by the following observations: (i) the range of optimal values for the single parameter of the new formulation is much less sensitive to grid resolution than that of the original formulation; (ii) within the optimal parameter range, the new formulation is able to maintain proper dissipation across scales and is thus able to produce better results in terms of errors in the potential enstrophy spectrum curves; and (iii) the new formulation is robust in that a single optimal parameter obtained for a specific grid can be safely used on other grids as well.
A Modified Flood Severity Assessment for Enhanced Decision Support: Application to the Boscastle Flash Flood of 2004
Authors: Murray S. J. , Smith A. D. , Phillips J. C. 
Published: June 2012

Abstract
A modified flash flood severity assessment is presented, based on scoring a set of factors according to their potential for generating extreme catchment-scale flooding. Improvements are made to the index through incorporation of parameter uncertainties, managing data absence, and clearer graphical communication. The motive for proposing these changes is to better inform flood managers during the development of a flash flood that may require an emergency response. This modified decision-support system is demonstrated for the Boscastle flood of 2004 and other historical floods in the United Kingdom. For Boscastle, the extreme nature of the flood is underestimated, which is likely to be due to the lack of sophistication in weighting flood parameters. However, the proposed amendments are able to rapidly reflect the reliability of a catchment severity rating, which may further enhance this technique as a decision-support tool alongside radar observations of localized storms.
Do African American Women Require Fewer Calories to Maintain Weight?
Authors: Brewer LaPrincess C. , Miller Edgar R. , Appel Lawrence J. , Anderson Cheryl A. M. 
Published: June 2012

Background:The high prevalence of obesity in African American (AA) women may result, in part, from a lower resting metabolic rate (RMR) than non‐AA women. If true, AA women should require fewer calories than non‐AA women to maintain weight. Our objective was to determine in the setting of a controlled feeding study, if AA women required fewer calories than non‐AA women to maintain weight.Materials and Methods:This analysis includes 206 women (73% AA), aged 22–75 years, who participated in the Dietary Approaches to Stop Hypertension (DASH) trial—a multicenter, randomized, controlled, feeding study comparing the effects of 3 dietary patterns on blood pressure in individuals with prehypertension or stage 1 hypertension. After a 3‐week run‐in, participants were randomized to 1 of 3 dietary patterns for 8 weeks. Calorie intake was adjusted during feeding to maintain stable weight. The primary outcome of this analysis was average daily calorie (kcal) intake during feeding.Results:AA women had higher baseline weight and body mass index than non‐AA women (78.4 vs 72.4 kg, P < .01; 29.0 vs 27.6 kg/m2, P < .05, respectively). During intervention feeding, mean (SD) kcal was 2168 (293) in AA women and 2073 (284) in non‐AA women. Mean intake was 94.7 kcal higher in AA women than in non‐AA women (P < .05). After adjustment for potential confounders, there was no difference in caloric intake between AA and non‐AA women (Δ = −2.8 kcal, P = .95).Conclusion:These results do not support the view that AA women are at greater risk for obesity because they require fewer calories to maintain weight.
The key role of repeated DNAs in sex chromosome evolution in two fish species with ZW sex chromosome system
Authors: de Bello Cioffi Marcelo , Kejnovský Eduard , Marquioni Vinicius , Poltronieri Juliana , Molina Wagner Franco , Diniz Débora , Bertollo Luiz Antonio Carlos 
Published: June 2012

Abstract
Despite substantial progress, there are still several gaps in our knowledge about the process of sex chromosome differentiation. The degeneration of sex-specific chromosome in some species is well documented, but it is not clear if all species follow the same evolutionary pathway. The accumulation of repetitive DNA sequences, however, is a common feature. To better understand this involvement, fish species emerge as excellent models because they exhibit a wide variety of sex chromosome and sex determining systems. Besides, they have much younger sex chromosomes compared to higher vertebrates, making it possible to follow early steps of differentiation. Here, we analyzed the arrangement of 9 repetitive DNA sequences in the W chromosomes of 2 fish species, namely Leporinus reinhardti and Triportheus auritus, which present well-differentiated ZZ/ZW sex system, but differ in respect to the size of the sex-specific chromosome. Both W chromosomes are almost fully heterochromatic, with accumulation of repeated DNAs in their heterochromatic regions. We found that microsatellites have strongly accumulated on the large W chromosome of L. reinhardti but not on the reduced-size W chromosome of T. auritus and are therefore important players of the W chromosome expansion. The present data highlight that the evolution of the sex chromosomes can diverge even in the same type of sex system, with and without the degeneration of the specific-sex chromosome, being more dynamic than traditionally appreciated.
Illumination preference, illumination constancy and colour discrimination by bumblebees in an environment with patchy light
Authors: Arnold Sarah E. J. , Chittka Lars 
Published: June 2012

SUMMARY
Patchy illumination presents foraging animals with a challenge, as the targets being sought may appear to vary in colour depending on the illumination, compromising target identification. We sought to explore how the bumblebee Bombus terrestris copes with tasks involving flower colour discrimination under patchy illumination. Light patches varied between unobscured daylight and leaf-shade, as a bee might encounter in and around woodland. Using a flight arena and coloured filters, as well as one or two different colours of artificial flower, we quantified how bees chose to forage when presented with foraging tasks under patchy illumination. Bees were better at discriminating a pair of similar colours under simulated unobscured daylight illumination than when foraging under leaf-shade illumination. Accordingly, we found that bees with prior experience of simulated daylight but not leaf-shade illumination initially preferred to forage in simulated daylight when all artificial flowers contained rewards as well as when only one colour was rewarding, whereas bees with prior experience of both illuminants did not exhibit this preference. Bees also switched between illuminants less than expected by chance. This means that bees prefer illumination conditions with which they are familiar, and in which rewarding flower colours are easily distinguishable from unrewarding ones. Under patchy illumination, colour discrimination performance was substantially poorer than in homogenous light. The bees' abilities at coping with patchy light may therefore impact on foraging behaviour in the wild, particularly in woodlands, where illumination can change over short spatial scales.
Divergence of desiccation-related traits in two Drosophila species of the takahashii subgroup from the western Himalayas
Authors: Parkash Ravi , Ramniwas Seema , Kajla Babita , Aggarwal Dau Dayal 
Published: June 2012

SUMMARY
Drosophila nepalensis is more abundant under colder and drier montane habitats in the western Himalayas compared with Drosophila takahashii, but the mechanistic basis of such a climatic adaptation is largely unknown. We tested the hypothesis that divergence in the physiological basis of desiccation-related traits is consistent with species-specific adaptations to climatic conditions. Drosophila nepalensis showed approximately twofold higher desiccation resistance, hemolymph content as well as carbohydrate content than D. takahashii despite a modest difference in rate of water loss (0.3% h–1). Water loss before succumbing to death (dehydration tolerance) was much higher in D. nepalensis (82.32%) than in D. takahashii (∼50%). A greater loss of hemolymph water under desiccation stress until death is associated with higher desiccation resistance in D. nepalensis. In both species, carbohydrates were utilized under desiccation stress, but a higher level of stored carbohydrates was evident in D. nepalensis. Further, we found increased desiccation resistance in D. nepalensis through acclimation whereas D. takahashii lacked such a response. Thus, species-specific divergence in water-balance-related traits in these species is consistent with their adaptations to wet and dry habitats.
Differential effects of chronic hypoxia and feed restriction on the expression of leptin and its receptor, food intake regulation and the endocrine stress response in common carp
Authors: Bernier Nicholas J. , Gorissen Marnix , Flik Gert 
Published: June 2012

SUMMARY
Appetite suppression is a common response to hypoxia in fish that confers significant energy savings. Yet little is known about the endocrine signals involved in the regulation of food intake during chronic hypoxia. Thus, we assessed the impact of chronic hypoxia on food intake, the expression of the potent anorexigenic signal leptin and its receptor (lepr), the mRNA levels of key hypothalamic appetite-regulating genes, and the activity of the hypothalamic–pituitary–interrenal (HPI) axis in common carp, Cyprinus carpio. Fish exposed to 10% O2 saturation for 8 days were chronically anorexic and consumed on average 79% less food than normoxic controls. Hypoxia also elicited gradual and parallel increases in the expression of liver leptin-a-I, leptin-a-II, lepr and erythropoietin, a known hypoxia-responsive gene. In contrast, the liver mRNA levels of all four genes remained unchanged in normoxic fish pair-fed to the hypoxia treatment. In the hypothalamus, expression of the appetite-regulating genes were consistent with an inhibition and stimulation of hunger in the hypoxic and pair-fed fish, respectively, and reduced feed intake led to a decrease in lepr. Although both treatments elicited similar delayed increases in plasma cortisol, they were characterized by distinct HPI axis effector transcript levels and a marked differential increase in pituitary lepr expression. Together, these results show that a reduction in O2 availability, and not feed intake, stimulates liver leptin-a expression in common carp and suggest that this pleiotropic cytokine is involved in the regulation of appetite and the endocrine stress response during chronic hypoxia.
Further insight into the sound-producing mechanism of clownfishes: what structure is involved in sound radiation?
Authors: Colleye Orphal , Nakamura Masaru , Frédérich Bruno , Parmentier Eric 
Published: June 2012

SUMMARYIt was recently demonstrated that clownfishes produce aggressive sounds by snapping their jaw teeth. To date, only the onset of the sound has been studied, which raises the question, what structure is involved in sound radiation? Here, a combination of different approaches has been used to determine the anatomical structure(s) responsible for the size-related variations observed in sound duration and frequency. Filling the swimbladder with physiological liquid specifically modified size-related acoustic features by inducing a significant decrease in pulse duration of approximately 3 ms and a significant increase in dominant frequency of approximately 105 Hz. However, testing the acoustics of the swimbladder by striking it with a piezoelectric impact hammer showed that this structure is a highly damped sound source prevented from prolonged vibrations. In contrast, the resonant properties of the rib cage seems to account for the size-related variations observed in acoustic features. For an equivalent strike on the rib cage, the duration and dominant frequency of induced sounds changed with fish size: sound duration and dominant frequency were positively and negatively correlated with fish size, respectively. Such relationships between sonic features and fish size are consistent with those observed in natural sounds emitted by fish. Therefore, the swimbladder itself does not act as a resonator; its wall just seems to be driven by the oscillations of the rib cage. This set of observations suggests the need for reassessment of the acoustic role of swimbladders in various fish species.
Differences in critical thermal maxima and mortality across life stages of the mealworm beetle Tenebrio molitor
Authors: Vorhees Ashley S. , Bradley Timothy J. 
Published: June 2012

SUMMARY
Thermal limits to activity profoundly affect the abundance and distribution of ectothermic animals. Upper thermal limits to activity are typically reported as the critical thermal maximum (CTmax), the temperature at which activity becomes uncontrolled. Thermolimit respirometry is a new technique that allows CTmax to be quantified in small animals, such as insects, as the point of spiracular failure by measuring CO2 release from the animal as temperature increases. Although prior studies have reported a characteristic pattern of CO2 release for insects during thermolimit respirometry trials, no studies have been carried out to determine the universality of this pattern across development, or at what point death occurs along this pattern. Here, we compared the CTmax and patterns of CO2 release among three life stages of a beetle species, Tenebrio molitor, and mapped heat death onto these patterns. Our study is the first to report distinct patterns of CO2 release in different life stages of an insect species during thermolimit respirometry. Our results show that CTmax was significantly higher in adult beetles than in either larvae or pupae (P&lt;0.001) and, similarly, death occurred at higher temperatures in adults than in larvae and pupae. We also found that death during heating closely follows CTmax in these animals, which confirms that measuring the loss of spiracular control with thermolimit respirometry successfully identifies the point of physiological limitation during heat stress.
Corporate Strategy, Analyst Coverage, and the Uniqueness Paradox
Authors: Litov Lubomir P. , Moreton Patrick , Zenger Todd R. 
Published: June 2012

In this paper, we argue that managers confront a paradox in selecting strategy. On one hand, capital markets systematically discount uniqueness in the strategy choices of firms. Uniqueness in strategy heightens the cost of collecting and analyzing information to evaluate a firm's future value. These greater costs in strategy evaluation discourage the collection and analysis of information regarding the firm, and result in a valuation discount. On the other hand, uniqueness in strategy is a necessary condition for creating economic rents and should, except for this information cost, be positively associated with firm value. We find empirical support for both propositions using a novel measure of strategy uniqueness in a firm panel data set between 1985 and 2007. This paper was accepted by Bruno Cassiman, business strategy.
Empirical Investigation of Retail Expansion and Cannibalization in a Dynamic Environment
Authors: Pancras Joseph , Sriram S. , Kumar V. 
Published: June 2012

Managers of retail chains who seek to add new stores or close existing ones need to know the net impact of a store's opening/closure on the overall chain performance. This requires inferring the extent to which each store generates incremental sales as opposed to competing with other stores belonging to the chain for the same set of customers. However, when the chain is experiencing a growth or a decline in sales, not accounting for these dynamics in goodwill is likely to yield misleading estimates of incremental sales versus cannibalization. Moreover, firms might have been strategic in opening outlets in locations with favorable characteristics. We need to control for this location endogeneity while inferring the marginal effect of store opening/closure. In this paper, we develop a demand model that accounts for dynamics in goodwill, location endogeneity, and spatial competition between geographically proximate retail outlets. We calibrate the model parameters on both attitudinal and behavioral data for a fast food chain in a large U.S. city. The results imply that consumers perceive a travel cost of $0.60 per mile. As regards the composition of sales at individual stores, on average, 86.7% of sales constitute incremental purchases with the rest derived from cannibalized sales from nearby stores belonging to the chain. We also find significant decay in cannibalization with distance such that when the distance between stores increases by one mile, the sales lost due to cannibalization decreases by 28.1%; there is virtually no cannibalization at a distance of 10 miles. In terms of managerial applications, we discuss how managers can use the model presented in this paper to make two key decisions: (a) isolating locations that can be closed by identifying stores that yield the lowest marginal benefit to the chain and (b) dealing with franchisees' potential concerns about cannibalization. This paper was accepted by Preyas Desai, marketing.