bluuebunny/crossref_metadata_2025_split huggingface dataset:
PIGEONS' CHOICES WITH TOKEN STIMULI IN CONCURRENT VARIABLE‐INTERVAL SCHEDULES
Authors: Mazur James E. , Biondi Dawn R. 
Published: March 2013

AbstractTwelve pigeons responded on concurrent variable‐interval schedules that delivered token stimuli (stimulus lights for some pigeons, and white circles on the response keys for others). During exchange periods, each token could be exchanged for food on a fixed‐ratio 1 schedule. Across conditions, the exchange requirements (number of tokens that had to be earned before they could be exchanged for food) varied between one and four for the two response keys. The main findings were that the pigeons' response percentages varied as a function of the number of tokens earned at any given moment, and they were determined by both the delays to food and by the number of food deliveries in the exchange periods. In some conditions, tokens had to be earned but were not visible during the variable‐interval schedules for one or both keys. When one key had visible tokens and the other did not, the pigeons showed a preference for the key without visible tokens. A model based on the matching law and a hyperbolic delay‐discounting equation could account for the main patterns of choice responding, and for how response percentages changed as successive tokens were earned. The results are consistent with the view that the token stimuli served as discriminative stimuli that signaled the current delays to food.
RESPONSE ACQUISITION WITH INTERMITTENT IMMEDIATE AND DELAYED CONDITIONED REINFORCEMENT
Authors: Bermúdez Karina , Bruner Carlos A. , Lattal Kennon A. 
Published: March 2013

AbstractThe acquisition of lever pressing by rats was studied under intermittent immediate and delayed conditioned reinforcement. Rats were exposed to two schedules operating concomitantly. One was a random‐time schedule that delivered reinforcers on average of once per min. Each such reinforcer was paired with a 1‐s illumination of a cue light located above the lever. The other was a tandem random‐interval (RI) t1‐ s fixed‐time (FT) t2‐ s schedule that controlled the rate and the delay of the illumination of the cue‐light after a given lever press. For the RI, t1 was 7.5, 15 or 30 s. For the FT, t2 was 0, 1, 2, 4, 8, 16 or 32 s. Three rats each were exposed to each combination of RI and FT values for 40 sessions. Response rates decreased with longer response‐conditioned reinforcer (Sr) delays under the three different overall rates of Sr. At most response‐Sr delays, absolute response rates were higher with RI 15 s than with RI 30 s but both were similar to those obtained with RI 7.5 s. The results were similar to those from previous research on response acquisition with delayed primary reinforcement. These findings suggest that a previously neutral stimulus that has been correlated with primary reinforcement can reinforce new responses even when the conditioned reinforcer is intermittent and delayed from the responses that produce it.
Effects of Anatomy and Diet on Gastrointestinal pH in Rodents
Authors: Kohl Kevin D. , Stengel Ashley , Samuni‐Blank Michal , Dearing M. Denise 
Published: March 2013

AbstractThe pH of the gastrointestinal tract can have profound influences on digestive processes. Rodents exhibit wide variation in both stomach morphology and dietary strategies, both of which may influence gut pH. Various rodent species have evolved bilocular (or semi‐segmented) stomachs that may allow for more microbial growth compared to unilocular (single‐chambered) stomachs. Additionally, herbivory has evolved multiple times in rodents. The high dietary fiber typical of an herbivorous diet is known to induce secretion of bicarbonate in the gut. We predicted that stomach segmentation might facilitate the separation of contents in the proximal chamber from that of the gastric stomach, facilitating a chemical environment suitable to microbial growth. To investigate the effect of stomach anatomy and diet on gut pH, several species of rodent with varying stomach morphology were fed either a high or low‐fiber diet for 7 days, and pH of the proximal stomach, gastric stomach, small intestine, and cecum were measured. We discovered that rodents with bilocular stomach anatomy maintained a larger pH gradient between the proximal and gastric stomach compartments, and were able to achieve a lower absolute gastric pH compared to those with unilocular stomachs. Dietary fiber increased the pH of the small intestine, but not in any other gut regions. The stomach pH data supports the century old hypothesis that bilocular stomach anatomy creates an environment in the proximal stomach that is suitable for microbial growth. Additionally, the alkaline small intestinal pH on a high fiber diet may enhance digestion. J. Exp. Zool. 319A:225–229, 2013. © 2013 Wiley Periodicals, Inc.
Analysis of internal winding short circuit faults in power transformers using transient finite element method coupling with external circuit equations
Authors: Behjat Vahid , Vahedi Abolfazl 
Published: March 2013

SUMMARYInterturn short circuit faults are the leading cause of power transformer failures. If not quickly detected, these faults usually develop into more serious faults, which would result in irreversible damage to the transformer, unexpected outages, and consequential costs. The aim of this research is to obtain a better understanding of the physical behavior of the power transformers in the presence of interturn faults as well as to discover the best indicators for detection of interturn short circuit faults. To this end, a time stepping finite element model of power transformer has been developed to analyze the transient behavior of a real power transformer when the transformer is working under winding short circuit fault conditions. The transient model, coupled with external circuit equations, allows us to simulate the dynamic behavior of the transformer with the real power supply and external loads connections. The FEM computations show the ability of the electromagnetic flux inside the transformer, transformer terminal currents, and circulating current in the shorted turns as useful monitoring parameters for transformer fault detection. Copyright © 2013 John Wiley & Sons, Ltd.
Monte Carlo analysis of dynamic characteristics and high‐frequency noise performances of nanoscale double‐gate MOSFETs
Authors: Chen Yongbo , Jo Michael , Mohamed Mohamed , Xu Ruimin 
Published: March 2013

ABSTRACTIn this paper, a full‐band Monte Carlo simulator is employed to study the dynamic characteristics and high‐frequency noise performances of a double‐gate (DG) metal–oxide–semiconductor field‐effect transistor (MOSFET) with 30 nm gate length. Admittance parameters (Y parameters) are calculated to characterize the dynamic response of the device. The noise behaviors of the simulated structure are studied on the basis of the spectral densities of the instantaneous current fluctuations at the drain and gate terminals, together with their cross‐correlation. Then the normalized noise parameters (P, R, and C), minimum noise figure (NFmin), and so on are employed to evaluate the noise performances. To show the outstanding radio‐frequency performances of the DG MOSFET, a single‐gate silicon‐on‐insulator MOSFET with the same gate length is also studied for comparison. The results show that the DG structure provides better dynamic characteristics and superior high‐frequency noise performances, owing to its inherent short‐channel effect immunity, better gate control ability, and lower channel noise. Copyright © 2012 John Wiley & Sons, Ltd.
Assessment of the utility of the 2‐µ thulium laser in surgical removal of intracranial meningiomas
Authors: Passacantilli Emiliano , Anichini Giulio , Lapadula Gennaro , Salvati Maurizio , Lenzi Jacopo , Santoro Antonio 
Published: March 2013

AbstractBackground and ObjectiveSince the 1960s, lasers have been used in neurosurgery for surgical removal of intracranial tumors. Because of its limited penetration (2 mm) through tissues and its wavelength, which is useful in water medium, the 2‐µ thulium laser has been applied primarily in urology. Its features are attractive for application under microscope magnification during neurosurgical procedures. The aim of this study was to evaluate the usefulness of the 2‐µ thulium laser during microsurgical removal of intracranial meningiomas.Materials and MethodsTwenty patients with a diagnosis of intracranial meningiomas were treated with surgical intervention using a 2‐µ thulium laser together with bipolar forceps, cavitron ultrasonic surgical aspirator (CUSA) and traditional microdissection instruments. Surgical removal was divided in four phases: (1) dissection from the external structures; (2) coagulation and debulking; (3) dissection from the deep structures; and (4) coagulation and removal of the basal implant. During all these steps, we evaluated the percentage of usage of the 2‐µ thulium laser comparing them with bipolar forceps and ultrasonic aspirator and blunt dissection.ResultsThulium laser was used mainly during phases 2 and 4 for 43% and 48.7% of the total removal, respectively. Although also useful during phases 1 and 3, it was only used for 2.2% and 31.3%, respectively: traditional dissection with scissors and forceps was preferred.ConclusionsThulium laser seems to be a useful aid in the surgery of intracranial meningiomas, especially to debulk, shrink, and coagulate the mass and the basal implant. Lasers Surg. Med. 45: 148–154, 2013. © 2013 Wiley Periodicals, Inc.
Buffer‐Stable Chitosan–Polyglutamic Acid Hybrid Nanoparticles for Biomedical Applications
Authors: Malhotra Astha , Zhang Xiaolei , Turkson James , Santra Swadeshmukul 
Published: March 2013

AbstractIn spite of their attractive features, widespread biomedical applications of CS nanoparticles are yet to be realized due to their poor stability in physiological conditions, such as in buffer system at pH 7.4. Buffer‐stable chitosan‐based hybrid NPs (HNPs) are reported and characterized. Buffer stability is achieved by introducing polyglutamic acid to chitosan. The effect of PGA to CS molar ratio and crosslinking on HNP integrity, buffer stability, and biodegradability are studied. Preliminary in vitro studies are carried out to evaluate targeted uptake efficiency of folate conjugated HNPs. Successful demonstration of buffer stability and cancer cell targeting by HNPs achieves important milestones for chitosan‐based nanoparticle technology. magnified image
UV‐Induced Frontal Polymerization of a Pt‐Catalyzed Hydrosilation Reaction
Authors: Sangermano Marco , Marchi Sophie , Ligorio Davide , Meier Patrick , Kornmann Xavier 
Published: March 2013

AbstractThe bis(acetylacetonato)platinum(II) is a common thermal catalyst for the hydrosilation reaction, and it is reported to serve also as a photoactivated catalyst for hydrosilation addition of silanes to alkenes and alkynes. In this paper, it is demonstrated that the UV‐activation of hydrosilation reaction proceeds via a thermal‐frontal mechanism. UV light activates the polymerization on the surface of the sample and, subsequently, the heat released by hydrosilation generates a thermal front, converting the UV‐generated homogeneous catalyst to a Pt0 heterogeneous catalyst. The UV‐induced frontal polymerization mechanism can exhaustively explain the dark‐curing process observed in the UV‐activated hydrosilation reaction.magnified image
Response of serum and red blood cell folate concentrations to folic acid supplementation depends on methylenetetrahydrofolate reductase C677T genotype: Results from a crossover trial
Authors: Anderson Cheryl A. M. , Beresford Shirley A. A. , McLerran Dale , Lampe Johanna W. , Deeb Samir , Feng Ziding , Motulsky Arno G. 
Published: March 2013

ScopeBy increasing blood folate concentrations, folic acid supplementation reduces risk for neural tube defect‐affected pregnancies, and lowers homocysteine concentrations. We assessed response of red blood cell (RBC) and serum folate to folic acid supplementation, and examined association of response with the genetic polymorphism C677T of the methylenetetrahydrofolate NAD(P)H (MTHFR) gene.Methods and resultsRandomized, controlled, crossover trial with two folic acid supplement treatment periods and a 30‐week washout period. The primary outcome is blood folate (serum and RBC) concentrations. Volunteers (n = 142) aged 18–69 were randomized to two of three doses (0, 200, and 400 μg) of folic acid for 12 weeks. Serum folate response depended on treatment period with significant responses to 200 μg seen only in the second treatment periods (4.4 ng/mL or 3.4 ng/mL). Additionally, serum folate increased as folic acid dose increased to 400 μg (p < 0.01) and response was greater after the washout period (8.7 ng/mL), than after a 6‐week run‐in (2.3 ng/mL). The differential change attributable to a daily supplement of 400 μg compared to 200 μg was 96.8 ng/mL; while the change attributable to 400 μg compared to 0 μg was 121.4. Increases in RBC folate concentrations with 400 μg occurred within MTHFR gene mutation (C677T); and in the African American group.ConclusionSerum folate concentration is responsive to modest increases in folic acid intake. RBC folate increases only with higher additional doses of folic acid supplementation, and this is true for each MTHFR C677T genotype.
Long‐term safety, tolerability and efficacy of flexible‐dose fesoterodine in elderly patients with overactive bladder: Open‐label extension of the SOFIA trial
Authors: Wagg Adrian , Khullar Vik , Michel Martin C. , Oelke Matthias , Darekar Amanda , Bitoun Caty Ebel 
Published: March 2013

AbstractAimsTo assess the long‐term safety, tolerability, and efficacy of flexible‐dose fesoterodine in elderly patients with OAB.MethodsPatients aged ≥65 years who completed a 12‐week, randomized, double‐blind, placebo‐controlled trial were eligible for the 12‐week, open‐label (OL) extension phase. Patients who received double‐blind placebo started on fesoterodine 4 mg and could increase to 8 mg after 4 or 8 weeks of OL treatment, while fesoterodine‐treated patients continued on their double‐blind dose; only one dose escalation or de‐escalation was permitted. Discontinuations and adverse events (AEs) were monitored, and patients completed 3‐day bladder diaries and patient‐reported outcomes at the beginning and end of the 12‐week OL phase.ResultsSix hundred fifty‐four patients entered the 12‐week OL extension (mean age 72 years; 52% women). AEs were reported by 30.7% and 48.1% of patients who had received double‐blind fesoterodine and placebo, respectively; 1.9% and 9.4%, discontinued due to AEs, respectively. Patients who received double‐blind fesoterodine maintained their efficacy response. After 12 weeks of OL treatment, efficacy outcomes in patients who received double‐blind placebo were similar to those who had received double‐blind fesoterodine. On average, the efficacy response was maintained for the duration of the study.ConclusionsFesoterodine was well tolerated and improvements in OAB symptoms and quality of life measures were not diminished with longer‐term treatment of patients aged ≥65 years. Neurourol. Urodynam. 33:106–114, 2014. © 2013 Wiley Periodicals, Inc.
Complexity and approximability of the maximum flow problem with minimum quantities
Authors: Thielen Clemens , Westphal Stephan 
Published: March 2013

AbstractWe consider the maximum flow problem with minimum quantities (MFPMQ), which is a variant of the maximum flow problem where the flow on each arc in the network is restricted to be either zero or above a given lower bound (a minimum quantity), which may depend on the arc. This problem has recently been shown to be weakly NP ‐complete even on series–parallel graphs. In this article, we provide further complexity and approximability results for MFPMQ and several special cases. We first show that it is strongly NP ‐hard to approximate MFPMQ on general graphs (and even bipartite graphs) within any positive factor. On series–parallel graphs, however, we present a pseudo‐polynomial time dynamic programming algorithm for the problem. We then study the case that the minimum quantity is the same for each arc in the network and show that, under this restriction, the problem is still weakly NP ‐complete on general graphs, but can be solved in strongly polynomial time on series–parallel graphs. On general graphs, we present a
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‐approximation algorithm for this case, where λ denotes the common minimum quantity of all arcs. © 2013 Wiley Periodicals, Inc. NETWORKS, 2013
A posteriori error estimates in quantities of interest for the finite element heterogeneous multiscale method
Authors: Abdulle Assyr , Nonnenmacher Achim 
Published: March 2013

AbstractWe present an “a posteriori” error analysis in quantities of interest for elliptic homogenization problems discretized by the finite element heterogeneous multiscale method. The multiscale method is based on a macro‐to‐micro formulation, where the macroscopic physical problem is discretized in a macroscopic finite element space, and the missing macroscopic data are recovered on‐the‐fly using the solutions of corresponding microscopic problems. We propose a new framework that allows to follow the concept of the (single‐scale) dual‐weighted residual method at the macroscopic level in order to derive a posteriori error estimates in quantities of interests for multiscale problems. Local error indicators, derived in the macroscopic domain, can be used for adaptive goal‐oriented mesh refinement. These error indicators rely only on available macroscopic and microscopic solutions. We further provide a detailed analysis of the data approximation error, including the quadrature errors. Numerical experiments confirm the efficiency of the adaptive method and the effectivity of our error estimates in the quantities of interest. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
Two‐grid methods for semilinear interface problems
Authors: Holst Michael , Szypowski Ryan , Zhu Yunrong 
Published: March 2013

AbstractIn this article, we consider two‐grid finite element methods for solving semilinear interface problems in d space dimensions, for d = 2 or d = 3. We consider semilinear problems with discontinuous diffusion coefficients, which includes problems containing subcritical, critical, and supercritical nonlinearities. We establish basic quasioptimal a priori error estimates for Galerkin approximations. We then design a two‐grid algorithm consisting of a coarse grid solver for the original nonlinear problem, and a fine grid solver for a linearized problem. We analyze the quality of approximations generated by the algorithm and show that the coarse grid may be taken to have much larger elements than the fine grid, and yet one can still obtain approximation quality that is asymptotically as good as solving the original nonlinear problem on the fine mesh. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
An orthogonal subspace minimization method for finding multiple solutions to the defocusing nonlinear Schrödinger equation with symmetry
Authors: Wang Changchun , Zhou Jianxin 
Published: March 2013

AbstractAn orthogonal subspace minimization method is developed for finding multiple (eigen) solutions to the defocusing nonlinear Schrödinger equation with symmetry. As such solutions are unstable, gradient search algorithms are very sensitive to numerical errors, will easily break symmetry, and will lead to unwanted solutions. Instead of enforcing a symmetry by the Haar projection, the authors use the knowledge of previously found solutions to build a support for the minimization search. With this support, numerical errors can be partitioned into two components, sensitive versus insensitive to the negative gradient search. Only the sensitive part is removed by an orthogonal projection. Analysis and numerical examples are presented to illustrate the method. Numerical solutions with some interesting phenomena are captured and visualized by their solution profile and contour plots. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
A morphometric study of the human fetal heart on post‐mortem 3‐tesla magnetic resonance imaging
Authors: Sandaite Inga , De Catte Luc , Moerman Philippe , Gewillig Marc , Fedele Luigi , Deprest Jan , Claus Filip 
Published: March 2013

ABSTRACTObjectiveTo report on the feasibility of assessing cardiac structures on post‐mortem 3‐tesla MRI (pmMRI) and to provide morphometric data in fetuses without cardiac abnormalities.MethodsRetrospective single center study on 3T pmMRI of 39 consecutive fetuses without cardiac abnormalities (13–38 weeks of gestation). Fetal cardiac anatomy was assessed and measurements of cardiac structures were performed on T2‐weighted 3D multiplanar reconstructed images. Linear regression analysis was performed to examine changes of cardiac dimensions during gestation.ResultsThe four‐chamber view of the fetal heart could be obtained and the measurements of cardiac chambers and ventricular walls could be performed in all 39 cases. The aorta and the pulmonary artery were visualized and their diameters were measured in 38 (97.4%) fetuses, ductus arteriosus in 32 (82%). All measurements showed strong linear correlation with gestational age. The relationship of the diameters of the pulmonary artery, aorta, and ductus arteriosus remained constant over pregnancy. All these observations are consistent with what is known from prenatal ultrasound.ConclusionsThe present study proves the feasibility of visualizing normal cardiac structures on 3‐tesla pmMRI in fetuses beyond 14 weeks. We provide morphometric data that may enable diagnostic evaluation of cardiac abnormalities on pmMRI. © 2013 John Wiley & Sons, Ltd.
Azilsartan (Edarbi): a new ARB for treating hypertension
Authors: Chaplin Steve , McInnes Gordon 
Published: March 2013

AbstractAzilsartan medoxomil (Edarbi) is a new angiotensin‐II receptor blocker for use in the treatment of hypertension. In our New products review, Steve Chaplin presents the clinical data relating to its efficacy and adverse events and Professor Gordon McInnes discusses its place in treatment.
Houston's Emerging Exposure between African Americans and Whites: Evidence of Spatial Assimilation or Place Stratification?
Authors: Waren Warren 
Published: March 2013

ABSTRACTThe persistent finding of a racial gap in residential attainment between African Americans and whites has led to a critique, which argues that spatial assimilation theory does not explain the residential segregation of African Americans, even though it explains segregation for other groups. That critique is typically based on analyses of cross‐sectional data, which do not take into account demographic context. In this paper, I examine demographically adjusted exposure scores for educational categories of race and ethnic groups in Houston, Texas, between 1970 and 2000. I find that starting in 1980 higher status African Americans achieved greater spatial assimilation. My findings suggest that analyses that rely on demographically appropriate measures and trend data indicate that spatial assimilation theory is relevant to changes in the residential mobility of African Americans. Copyright © 2013 John Wiley & Sons, Ltd.