bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of average symbol error rate and optimal power allocation for two‐way opportunistic relaying with amplify‐and‐forward protocol
Authors: Zhi Hui , Jia Xiangdong , Yang Longxiang , Fu Haiyang 
Published: May 2012

SUMMARYIn this paper, we investigate the statistical characteristics of the equivalent end‐to‐end signal‐to‐noise ratios (SNRs), the average symbol error ratios (SERs), and the optimal power allocation (OPA) for two‐way amplify‐and‐forward opportunistic relaying (TWOR‐AF) systems. First, with strict mathematic manipulation, we obtain the closed‐form solutions to the PDF, CDF, and moment generating function of the end‐to‐end SNRs. Then, based on the obtained statistical results, we present the total average SER of the Non‐OPA TWOR‐AF systems by using the appropriate approximation, in which only the greater segment of the two terminal SERs is considered. Finally, by aiming at minimizing the total average SER and using the SNRs balancing condition at both transceivers, we study the OPA problem subject to a total transmission power constraint. The comparison analysis shows that, for the Non‐OPA TWOR‐AF systems, we can only evaluate exactly the greater segment of the two SERs of the received signals at two transceivers by using the derivations. However, for the OPA TWOR‐AF systems, with our derivations we can evaluate exactly not only each segment of the two terminal SERs but also the sum SER (exact total SER). Moreover, the simulations show the OPA TWOR‐AF systems outperform the Non‐OPA TWOR‐AF systems. Copyright © 2012 John Wiley & Sons, Ltd.
Deficits in trace fear conditioning induced by neonatal alcohol persist into adulthood in female rats
Authors: Schreiber William B. , Hunt Pamela S. 
Published: May 2012

AbstractThe developing hippocampus is particularly vulnerable to the toxic effects of alcohol, and behavioral deficits on hippocampus‐dependent tasks have been reported following neonatal alcohol exposure in rodents. Previously, we have found that trace fear conditioning (a hippocampus‐dependent learning task) is disrupted in rats exposed to alcohol during postnatal days (PD) 4–9, although delay fear conditioning is not. The present study indicates that this impairment in trace fear conditioning, previously only measured during adolescence, persists into adulthood but only in females. Animals were exposed to 5.0 g/kg/day alcohol on PD 4–9 and were trained on either PD 30 or 65. Alcohol exposure significantly impaired trace conditioning in both sexes at PD 30. In animals trained as adults, the deficit in trace was only observed in female subjects, suggesting that although males exhibit an age‐related recovery of function, alcohol‐induced trace conditioning deficits are more persistent in female Sprague–Dawley rats. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 352–360, 2013
Prevalence and co‐existence of active components of ‘legal highs’
Authors: Zuba Dariusz , Byrska Bogumiła 
Published: May 2012

The results of a study performed on samples of ‘legal highs’ seized in head shops by law enforcement and health services in Poland between mid‐2008 and mid‐2011 are presented. In total, 449 preparations which differed in labelling, net masses, forms of distribution, etc., were analyzed. A variety of sophisticated analytical methods, including gas chromatography–mass spectrometry (GC‐MS), liquid chromatography‐quadropole time‐of‐flight mass spectrometry (LC‐QTOF‐MS), high performance liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) were applied for component identification and quantification.The most common ingredients of legal highs were (in descending order): MPDV, caffeine, butylone, TFMPP, lidocaine, 4‐MEC, mephedrone, pFPP, BZP, and MDPBP. The scatter of substances changed over time, and piperazines were often ousted by cathinones. Most of the preparations were composed of two or more ingredients. Cathinones and piperazines were mixed mainly within the chemical classes (77.6% and 56.1% of dual links, respectively), caffeine was mixed both with piperazines (24 products) and cathinones (22 products), whereas lidocaine only with the latter class (47 products). A great inconsistency in the qualitative and quantitative composition of products with identical labelling was shown in an example of Coco products seized after August 2010; we found 10 different single component or mixture preparations, and the content of individual ingredients varied from several to hundreds of mgs.This paper summarizes potential dangers connected with the uncontrolled sale of psychoactive substances, and indicates important issues concerning the analysis of legal highs. Copyright © 2012 John Wiley & Sons, Ltd.
Antagonistic activities of Rho and Rac GTPases underlie the transition from neural crest delamination to migration
Authors: Shoval Irit , Kalcheim Chaya 
Published: May 2012

AbstractBackground: Neural crest progenitors arise as epithelial cells and then undergo a transition into mesenchyme that generates motility. Previously, we showed that active Rho maintains crest cells in the epithelial conformation by keeping stress fibers and membrane‐bound N‐cadherin. Results: While Rho disappears from cell membranes upon delamination, active Rac1 becomes apparent in lamellipodia of mesenchymal cells. Loss of Rac1 function at trunk levels inhibited NC migration but did not prevent cell emigration that is associated with N‐cadherin downregulation and G1/S transition. Furthermore, inhibition of Rho stimulated premature Rac1 activity and consequent formation of lamellipodia, leading to NC migration. To examine whether timely migration influences cell fate, Rac1 activity was transiently inhibited to delay dispersion of early NC cells that generate neural derivatives, and its activity was restored by the time of melanoblast migration. Even if confronted with a melanocytic environment, late‐dispersing progenitors colonized sensory ganglia where they generated neurons and glia. Conclusions: In the context of crest delamination and migration, activities of Rho and Rac are differential, sequential, and antagonistic. Furthermore, transient inhibition of Rac1 that delays the onset of crest dispersion raises the possibility that the fate of trunk neural progenitors might be restricted prior to migration. Developmental Dynamics 241:1155–1168, 2012. © 2012 Wiley Periodicals, Inc.
Population genetic dynamics of three‐spined sticklebacks (Gasterosteus aculeatus) in anthropogenic altered habitats
Authors: Scharsack Joern P. , Schweyen Hannah , Schmidt Alexander M. , Dittmar Janine , Reusch Thorsten B.H. , Kurtz Joachim 
Published: May 2012

AbstractIn industrialized and/or agriculturally used landscapes, inhabiting species are exposed to a variety of anthropogenic changes in their environments. Genetic diversity may be reduced if populations encounter founder events, bottlenecks, or isolation. Conversely, genetic diversity may increase if populations adapt to changes in selective regimes in newly created habitats. With the present study, genetic variability of 918 sticklebacks from 43 samplings (21.3 ± 3.8 per sample) at 36 locations from cultivated landscapes in Northwest Germany was analyzed at nine neutral microsatellite loci. To test if differentiation is influenced by habitat alterations, sticklebacks were collected from ancient running waters and adjacent artificial stagnant waters, from brooks with salt water inflow of anthropogenic and natural origin and adjacent freshwater sites. Overall population structure was dominated by isolation by distance (IBD), which was significant across all populations, and analysis of molecular variance (AMOVA) revealed that 10.6% of the variation was explained by river catchment area. Populations in anthropogenic modified habitats deviated from the general IBD structure and in the AMOVA, grouping by habitat type running/stagnant water explained 4.9% of variation and 1.4% of the variation was explained by salt‐/freshwater habitat. Sticklebacks in salt‐polluted water systems seem to exhibit elevated migratory activity between fresh‐ and saltwater habitats, reducing IBD. In other situations, populations showed distinct signs of genetic isolation, which in some locations was attributed to mechanical migration barriers, but in others to potential anthropogenic induced bottleneck or founder effects. The present study shows that anthropogenic habitat alterations may have diverse effects on the population genetic structure of inhabiting species. Depending on the type of habitat change, increased genetic differentiation, diversification, or isolation are possible consequences.
Copper Complexes with a Hybrid Scorpionate Ligand Containing Pyridazine‐3‐thione
Authors: Nuss Gernot , Ozwirk Anja , Harum Bastian N. , Saischek Gerald , Belaj Ferdinand , Mösch‐Zanetti Nadia C. 
Published: May 2012

AbstractA new scorpionate ligand, Na[HB(mim)2(PntBu)] (Na[PnBm]), with one pyridazinyl‐3‐thione and two methimazolyl (mim) substituents was prepared by mixing 6‐tert‐butylpyridazine‐3‐thione (HPntBu) and sodium dihydridobis(methimazolyl)borate (Na[Bm]) in boiling xylene. Addition of CuCl to a solution of Na[PnBm] in methanol in the presence of PR3 gave the monomeric copper(I) complexes [Cu{PnBm}(PR3)] (R = cyclohexyl 1, phenyl 2) in good yields. They were characterized by NMR spectroscopy and in the case of 2 also by single‐crystal X‐ray diffraction analysis. The latter revealed a compound in which the ligand is coordinated in a κ3‐S,S,H fashion, exhibiting a 3‐center‐2‐electron B–H···Cu interaction. Reaction of the ligand Na[PnBm] with CuCl in the absence of phosphane yielded a copper(I) complex, which was determined to be [Cu{PnBm}] (3). Variable‐temperature 1H NMR spectroscopy points to the occurrence of two dimeric isomers in solution, which interconvert in a fluxional behavior at room temperature. DFT calculations show that two isomers with a κ3‐Smim,Smim,H or a κ3‐Hmim,SPn,H coordination mode have very similar energies with a low energy barrier (25.4 kJ/mol) for their interconversion.
Acute and subacute oral toxicity of polychlorinated diphenyl sulfides in mice: Determining LD50 and assessing the status of hepatic oxidative stress
Authors: Zhang Xuesheng , Liu Fu , Chen Binyuan , Li Ying , Wang Zunyao 
Published: May 2012

Abstract
Polychlorinated diphenyl sulfides (PCDPSs), a series of dioxin-like compounds, have been detected in various environmental samples. However, information on the toxicity of these compounds is limited. In the present study, the toxic effects of PCDPSs were assessed after acute and subacute exposure in mice. Relationships between acute toxicity, number, and position of substituted Cl atoms were assessed. In the acute study, 11 types of PCDPSs were administered to female Kunming mice by gavage, and median lethal doses (LD50s) were determined by the Karber method. Results indicated that the LD50s of lower substituted PCDPSs were smaller than higher substituted PCDPSs. Substituted positions also influenced the LD50 of PCDPSs. Terminal necropsy showed increased relative liver weights and decreased relative kidney weights. Histological examination of livers demonstrated swollen cells, inflammation, vacuolization, and necrosis. In the 28-d subacute exposure tests, 11 types of PCDPSs were dissolved in corn oil and administered to mice at doses of 1, 10, and 100 mg/kg. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in mouse liver were determined after the exposure period. Results suggested that lower substituted PCDPSs decreased SOD activity in the high-dose groups compared with controls, and MDA level in the 100-mg/kg dose group was significantly increased. In addition, acute toxicity of PCDPSs partly corresponded to the hepatic oxidative damage observed. Environ. Toxicol. Chem. 2012; 31: 1485–1493. © 2012 SETAC
Network decomposition and multi‐path routing optimal control
Authors: Bruni Carlo , Priscoli Francesco Delli , Koch Giorgio , Pietrabissa Antonio , Pimpinella Laura 
Published: May 2012

ABSTRACTIn this work we face the Routing problem defined as an optimal control problem, with control variables representing the percentages of each flow routed along the available paths (multi‐path routing), and a set of cost functions corresponding to the two different objectives of traffic balancing and bottleneck load minimization. A key issue considered in this paper is the possibility of splitting the given network in sub‐networks, each one controlled by a separate subset of variables. This of course designs a decomposition of the original control problem in a set of easier‐to‐be‐dealt‐with lower dimensional problems. Some simulation results validate the procedure. Copyright © 2012 John Wiley & Sons, Ltd.
Analytical performance evaluation of a class of receivers with joint equalisation and residual carrier frequency offset estimation
Authors: Pedrosa P. , Dinis R. , Nunes F. 
Published: May 2012

ABSTRACTIn this paper, we consider a single‐carrier modulation combined with frequency‐domain equalisation block transmission with residual frequency errors. We employ a frequency‐domain iterative decision feedback equalisation (DFE) denoted iterative block‐decision feedback equalisation (IB‐DFE), which is combined with a decision‐directed carrier frequency offset (CFO) estimator. This estimator produces a CFO estimate within each iteration of the equaliser, which is used to compensate for the CFO. As the analytical study of the IB‐DFE is very hard because of the feedback chain, IB‐DFE receivers with joint symbol detection and carrier frequency synchronisation are also very difficult to tackle. To address this problem, we propose three new models. One models the decision‐directed CFO estimator, another models the IB‐DFE and finally one makes use of the previous two models to jointly characterise equalisation and carrier frequency synchronisation. In addition, a novel graphical tool for the convergence evaluation of the iterative receiver is included. Finally, we validate our models using Monte Carlo simulations and conclude that they are accurate for small and moderate residual CFO values. Copyright © 2012 John Wiley & Sons, Ltd.
The role of territorial coverage and product diversification in the multinationality‐performance relationship
Authors: Oh Chang Hoon , Contractor Farok J. 
Published: May 2012

AbstractThis article introduces additional fine‐grained distinctions to the study of the multinationality‐performance relationship, such as territorial coverage and product diversification. It shows that the territorial scope covered by the firm makes a substantial difference to the relationship between multinationality and performance. In addition, the effect of multinationality on performance can sometimes be outweighed by product diversification. The path of international expansion is a much more complex process than is shown by existing studies. The results of this study suggest three generic strategies for international expansion with which an MNE can increase its performance. Copyright © 2012 Strategic Management Society.
The role of context in the multinationality‐performance relationship: A meta‐analytic review
Authors: Kirca Ahmet H. , Roth Kendall , Hult G. Tomas M. , Cavusgil S. Tamer 
Published: May 2012

AbstractUsing meta‐analytic data from 47,849 firms across 152 independent samples reported in 141 studies, this study presents a systematic investigation of the moderating effects of firm‐, industry‐, and country‐level factors on the multinationality‐performance relationship. The findings indicate that the effects of multinationality on performance depend on type of multinationality, firm strategic motivations, industry characteristics, and home country factors. Importantly, our assessment also reveals that firm size and stage of internationalization are not significant moderators. Thus, the findings indicate that the search for more complex M‐P relationships (i.e., U‐shaped, inverse U‐shaped, horizontal S‐curve) has the potential to expand our understanding, only when the characteristics of different research contexts, measurement issues, and firm characteristics are taken into account in the theoretical development and research design stages of studies. Copyright © 2012 Strategic Management Society.
The use of condition specific outcome measures in economic appraisal
Authors: Brazier John , Dixon Simon 
Published: May 2012

AbstractDespite growing concern over the use of health utility measures in economic evaluations of health care programmes, economists have been reluctant to use the wealth of knowledge contained within studies using condition specific outcome measures (CSOMs). Problems with the measurement properties of many CSOMs means that the scope for their use in economic appraisal is extremely limited. This paper examines the potential uses of CSOMs in economics, namely: to provide valid descriptive material, to provide scales for comparing the effectiveness of interventions and to ‘validate’ the descriptive accuracy of economic measures of benefit. It is argued that valid descriptive information is essential for economic appraisal, no matter which method of evaluation is used. Generic measures have been criticised for being too narrow and insensitive to the consequences of specific conditions. CSOMs offer a rich source of information to produce quality adjusted life years (QALYs) but two potential methods, one of mapping health states from one scale to a QALY classification (such as Rosser), and the other, developing ‘exchange rates’ between scales are unsatisfactory. A more rigorous approach would necessitate a major research programme of revaluing existing CSOMs using preference based methods.Another interesting avenue of research would be to use the information from CSOMs to construct health scenarios for valuation.Given the current state of development of outcome measures, it seems advisable to use CSOMs alongside economic measures in trials. Such a strategy would help demonstrate the usefulness of economic measures to clinicians and to reconcile the two measures.
The changing distribution of a major surgical procedure across hospitals: Were supply shifts and disequilibrium important?
Authors: Friedman Bernard , Elixhauser Anne 
Published: May 2012

AbstractThis paper describes and analyzes the changing distribution across hospitals in the U.S. of total hip replacement surgery (THR) for the period 1980–1987. THR is one of the most costly single procedures contributing to health care expenses. Also, the use of THR exhibits a particularly high degree of geographic variation. Recent research pointed to shifts in demand as one plausible economic explanation for increasing use of THR. This paper questions whether shifts in supply may have been large enough to explain changes in patient mix and the relationship of patient mix to the number of procedures performed at a particular hospital. In addition, the relationship between total use of THR and the local availability of orthopaedic surgeons as well as the average allowable Medicare fee for standardized physician services is analyzed. These relationships might yield evidence to support a scenario of induced demand beyond the optimum for patients' welfare, or evidence of supply increase within a disequilibrium scenario.This study, using data for all THR patients in a large sample of hospitals, tends to reject the formulation of a market with independent supply and demand shifts where the supply shifts were the dominant forces. Hospitals with a larger number of THRs performed did not see a higher percentage of older, sicker, and lower income patients. It was more likely that demand shifts generated increases in capacity for surgical services. Moreover, there was little evidence for a persistent disequilibrium and only weak evidence for inducement Also, we found little evidence that hospitals responded to financial incentives inherent in the Medicare payment system after 1983 to select among THR candidates in favour of those with below average expected cost We did observe increased concentration over time of THR procedures in facilities with high volume—suggesting plausible demand shifts towards hospitals with a priori quality and cost advantages or who obtained those advantages with a high volume of patients.
Demand for insurance by elderly persons: Private purchases and employer provision
Authors: Shea Dennis G. , Stewart R. Patrick 
Published: May 2012

AbstractStudies of the demand for health insurance by elderly persons often inadequately address the distinctions between those who receive insurance through a former employer and those who purchase insurance on their own. The failure to distinguish these two modes of supplementing Medicare can lead to an inability to identify the effects of important independent variables. Using data from the Survey of Income and Program Participation this paper examines the demand for employer provided health insurance among retired pensioners using a bivariate probit model with partial observability and compares these results to other models of insurance demand among elderly persons.The results indicate that unobserved factors reducing the probability of being offered employer provided insurance are associated with increased acceptance. A comparison of the employer provided results with results from other models of the demand for privately purchased insurance indicates that different independent variables may determine the probability of having these types of insurance. Previous studies of insurance that have not distinguished between these two types of insurance may not provide reliable estimates of the relationship between independent variables and the probability of insurance coverage.
Perspectives in health economics
Authors: Phelps Charles E. 
Published: May 2012

AbstractThis paper, originally presented at the Institut d'Etudes Politiques de Paris, October 12, 1993, provides a perspective on envisioned changes in the practice of health economics. Foreseen changes include: (1) Study of more homogeneous units of analysis; (2) More original data gathering; (3) Increased attention to uncertainty and the supply of and demand for information; (4) Increased attention to institutional structures and their effects on economic behaviour; (5) Expansion of relevant tools for studying economic issues in health care; and (6) Continuing breakdown of disciplinary barriers between health economics and other disciplines. Of these, the two overriding features will be increased emphasis on understanding the many roles of uncertainty in economic behaviour, institutions, and outcomes in health care, and in the use of more and more ‘micro’ data to study these issues.