bluuebunny/crossref_metadata_2025_split huggingface dataset:
DEA performance evaluation based on BSC indicators incorporated
Authors: Chen Tser‐Yieth , Chen Ling‐hua 
Published: April 2007

PurposeThe purpose of this paper is to evaluate the performance of the semiconductor industry in Taiwan, which is the main economic life‐line in Taiwan. Operational performance is normally deemed as a key factor in industry. The importance of this issue can be measured through performance indices to observe the operational performance of Taiwan's semiconductor industry.Design/methodology/approachA combination of the data envelopment analysis (DEA) and the balanced scorecard (BSC) was employedFindingsThis study finds that the efficiency of every domestic semiconductor manufacturer is generally good, and concerning the four perspectives of the balanced scorecard, the most important for the domestic firm is the financial perspective, second is the internal process perspective, third the learning and innovation perspective, and most unimportantly customer perspective.Research limitations/implicationsOwing to the difficulties in data collection and the widespread ranges of the four major aspects, the application of the indices is limited in this paper. Therefore, the main suggestion of this study regarding future research directions is to expand the indices of the four aspects, in the hope of measuring the operating efficiency of enterprises in each aspect using more and improved indices.Practical implicationsThis application can be extended by the usage of the ratio analysis and the BSC method to enhance the validity of the DEA.Originality/valueWhen implementing DEA, traditional financial indices cannot obtain an in‐depth understanding of an enterprise, hence this study considers the four major constructs of the balanced scorecard in index selection, and employed these four major contracts to expand the indices that can be available for selection and gain a deeper understanding not only of the financial aspects, but also of customers, the internal process, learning, and innovation. It should be noted that the balanced scorecard can develop the performance goal from the perspective of job fulfillment, and uses this view to assess management performance. These indicators can reflect different focuses regarding job fulfillment, and produce pluralism in the performance indices.
Microstructural changes accompanying the opal‐A to opal‐CT transition: new evidence from the siliceous sinters of Geysir, Haukadalur, Iceland
Authors: JONES BRIAN , RENAUT ROBIN W. 
Published: April 2007

AbstractOpaline silica (opal‐A) has formed in marine, lacustrine and geothermal environments throughout geological time. During diagenesis opal‐A normally changes to opal‐CT, then opal‐C, and finally to quartz. Such changes commonly destroy the original fabrics and any fossils that opal‐A contained. The physical changes that accompany the opal‐A to opal‐CT transition, however, are known poorly. X‐ray diffraction analyses, electron microprobe analyses and high‐resolution, high‐magnification scanning electron microscope imagery of siliceous sinters from the Geysir geothermal area in Iceland show that opal‐A is formed of heterometric arrays of randomly packed microspheres (up to 5 μm diameter) with neighbouring spheres commonly being joined by small connection pads. In contrast, enlarged spheres, lepispheres, inverse opal (two types) and spindle frameworks with hexagonal motifs characterize opal‐CT. The textures in opal‐CT, which vary on a microscale, reflect the complex interplay between dissolution (e.g. inverse opal) and precipitation (e.g. enlarged spheres, spindle frameworks) that probably was mediated by groundwater in a near‐surface environment. The processes deciphered from these young rocks should, however, be applicable to sedimentary opal‐A and opal‐CT of all ages, irrespective of their origin.
Bat diversity and abundance associated with the degree of secondary succession in a tropical forest mosaic in south‐eastern Mexico
Authors: Castro‐Luna A. A. , Sosa V. J. , Castillo‐Campos G. 
Published: April 2007

AbstractUnder the hypothesis that bat diversity would be lower in the early stages of secondary succession and that species affected negatively by habitat modification would be more frequent in later successional stages, we evaluated how bats use 12 vegetation stands representing four stages of secondary succession, following disturbance caused by slash‐and‐burn agriculture and selective logging. We compared bat richness, abundance and diversity, and found that none of these variables was different among stages or rainy seasons. However, of the 10 most common bat species, two were significantly more abundant in stands at the early stages of secondary succession, while the opposite was true for three other species. Canopy cover mainly explains these patterns. Rainy season had no effect on the abundance of the common species. The results of this study indicate that although some frugivorous species were very abundant in the younger stands, the majority of the rare species were captured in older stands. The absence of rare and habitat‐specialized species from young successional stages close to primary forest suggests that, for effective bat conservation in landscapes modified by human activity, areas with original vegetation should be maintained to ensure the survivorship of sensitive‐to‐deforestation species.
Manipulating sex ratio to increase population growth: the example of the Lesser Kestrel
Authors: Lenz T. L. , Jacob A. , Wedekind C. 
Published: April 2007

AbstractSmall or decreasing populations call for emergency actions like, for example, captive breeding programs. Such programs aim at rapidly increasing population sizes in order to reduce the loss of genetic variability and to avoid possible Allee effects. The Lesser Kestrel Falco naumanni is one of the species that is currently supported in several captive breeding programs at various locations. Here, we model the demographic and genetic consequences of potential management strategies that are based on offspring sex ratio manipulation. Increased population growth could be achieved by manipulating female conditions and/or male attractiveness in the captive breeders and consequently shifting the offspring sex ratio towards more female offspring, which are then used for reintroduction. Fragmenting populations into wild‐breeding and captive‐breeding demes and manipulating population sex ratio both immediately increase the inbreeding coefficient in the next generation (i.e. decrease Ne) but may, in the long term, reduce the loss of genetic variability if population growth is restricted by the number of females. We use the Lesser Kestrel and the wealth of information that is available on this species to predict the long‐term consequences of various kinds of sex‐ratio manipulation. We find that, in our example and possibly in many other cases, a sex‐ratio manipulation that seems realistic could have a beneficial effect on the captive breeding program. However, the possible long‐term costs and benefits of such measures need to be carefully optimized.
Chemical Cardiac Sympathetic Denervation Hampers Defibrillation in the Dog
Authors: RUFFY RODOLPHE , LEONARD MICHAEL 
Published: April 2007

Cardiac Sympathetic Denervation and Defibrillation. Introduction: Cardiac defibrillation is influenced by several physical and nonphysical factors. Previous animal studies have shown that beta‐adrenergic stimulation facilitates the process of defibrillation. The purpose of this study was to examine the effects of chemical sympathetic denervation on the ability to defibrillate the canine heart. Methods and Results: Twelve chronically instrumented dogs underwent serial measurements of the energy required to defibrillate the heart, ten before and after treatment with 50 mg/kg 6‐hydroxydopaniine (6‐OHDA). Two of the animals received 1% ascorbic acid in 0.9% saline solution (the vehicle) only, and three dogs received the vehicle followed several weeks later by 6‐OHDA. Following treatment with 6‐OHDA, the energy to defibrillate the heart rose from 11.9 ± 7.4 J (baseline 1) and 14.3 ± 8.7 J (baseline 2) to 23.3 ± 10.8 J (P < 0.01 and < 0.05, respectively). In contrast, following saline administration, no significant change was measured in the energy required to defibrillate the heart. After 6‐OHDA, 5 of the 10 animals could not he defibrillated versus none of 5 after saline treatment (Chi square 3.750, P = 0.053). In surviving animals, a return of measurements to, or toward, baseline was measured after active treatment. Conclusions: In this chronically instrumented, closed chest animal model, chemical sympathetic denervation with 6‐OHDA hampered the process of cardiac defibrillation. These results support previous observations of a modulating effect of this process by adrenergic activity.
Tissue Magnesium Levels and the Arrhythmic Substrate in Humans
Authors: HAIGNEY MARK CP. , BERGER RONALD , SCHULMAN STEVEN , GERSTENBLITH GARY , TUNIN CAROL , SILVER BURTON , SILVERMAN HOWARD S. , TOMASELLI GORDON , CALKINS HUGH 
Published: April 2007

Magnesium and Arrhythmias. Introduction: Magnesium deficiency has been implicated in the pathogenesis of sudden death, but the investigation of arrhythmic mechanisms has been hindered by difficulties in measuring cellular tissue magnesium stores. Methods and Results: To see if magnesium deficiency is associated with a propensity toward triggered arrhythmias, we measured tissue magnesium levels and QT interval dispersion (as an index of repolarization dispersion) in 40 patients with arrhythmic complaints. Magnesium was measured in sublingual epithelium using X‐ray dispersive analysis. QT interval dispersion was assessed on 12‐lead surface F‐XCs in all patients, and programmed stimulation was performed in 28. The sublingual epithelial magnesium level ([Mg]i), but the not the serum level, correlated Inversely with QT interval dispersion in 40 patients (r = 0.58, P < 0.0.5); in 12 patients undergoing repeat testing on therapy, the change in magnesium also correlated inversely with the change in QT dispersion (r = 0.61, P < 0.05). Patients with left ventricular ejection fractions > 40% had significantly higher tissue magnesium and lower QT dispersion (34.5 ± 0.5 mEq/L, 81 ± 8 msec) than those with left ventricular ejection fractious < 40% (32.7 ± 0.5 mEq/L, P < 0.01, and 114 ± 9 msec, P < 0.05). There was no difference in either [Mg]i, or QT dispersion in the 16 patients with inducible monomorphic ventricular tachycardia versus the 12 noninducible patients. Conclusion: Reduced tissue magnesium stores may represent a significant risk factor for arrhythmias associated with abnormal repolarization, particularly in patients with poor left ventricular systolic function, but may not represent a risk for excitable gap arrhythmias associated with a fixed anatomic substrate (e.g., monomorphic ventricular tachycardia).
Effect of Ventricular Dilatation on Defibrillation Threshold in the Isolated Perfused Rabbit Heart
Authors: OTT PETER , REITER MICHAEL J. 
Published: April 2007

Ventricular Dilatation and DFT. Introduction: Ventricular dilatation has Important electrophysiologic effects, but its effect on ventricular defibrillation threshold (DFT) is unknown. Methods and Results: A fluid‐filled, latex balloon was placed in the left ventricular cavity of 19 isolated rabbit hearts. In each experiment, an undilated volume (equivalent to a left ventricular end‐diastolic pressure of approximately 0 mmHg) was compared to a dilated volume achieved by adding 1.0 mL of saline (n = 10) or 5% dextrose (n = 9) to the intracavitary balloon. Left ventricular effective refractory period (ERP) and DFT were determined at each volume. Defibrillation was attempted with a monophasic shock delivered between a patch electrode positioned over the posterior left ventricle (cathode) and a metallic aortic cannula (anode). DFT was determined using a modified “down/up” protocol with 10‐V steps. Ventricular dilatation increased the left ventricular end‐diastolic pressure from 0 ± 0.5 mmHg to 35 ± 3 mmHg (P < 0.001), decreased the average left ventricular ERP 15% (from 116 ± 3 msec to 99 ± 3 msec; P < 0.001), and increased the average DFT 30% (from 96 ± 4 V to 125 ± 7 V; P < 0.001). In one third of experiments, the dilated DFT was ≥ 150% of the DFT at zero volume. The mechanism of the observed increase in DFT is unknown but may be related to the decrease in refractoriness observed with ventricular dilatation. Conclusion: Acute ventricular dilatation in this model increased DFT an average of 30%, an effect not previously described. This observation may have implications for patients with implantable cardioverter defibrillators.
Transmembrane Voltage Changes Produced by Real and Virtual Electrodes During Monophasic Defibrillation Shock Delivered by an Implantable Electrode
Authors: EFIMOV IGOR R. , CHENG YUANNA N. , BIERMANN MARTIN , Van WAGONER DAVID R. , MAZGALEV TODOR N. , TCHOU PATRICK J. 
Published: April 2007

Defibrillation Shock‐Induced Virtual Electrodes. Introduction: Epicardial point stimulation produces nonuniform changes in the trans membrane voltage of surrounding cells with simultaneous occurrence of areas of transient positive and negative polarization. This is the phenomenon of virtual electrode. We sought to characterize the responses of epicardial ventricular tissue to the application of monophasic electric shocks from an internal transvenous implantable cardioverter defibrillator (ICD) lead. Methods and Results: Langendorff‐perfused rabbit hearts (n = 12) were stained with di‐4‐ANEPPS. A 9‐mm‐long distal electrode was placed in the right ventricle. A 6‐cm proximal electrode was positioned horizontally 3 cm posteriorly and 1 cm superiorly with respect to the heart. Monophasic anodal and cathodal pulses were produced by discharging a 150‐μF capacitor. Shocks were applied either during the plateau phase of an action potential (AP) or during ventricular fibrillation. Leading‐edge voltage of the pulse was 50 to 150 V, and the pulse duration was 10 msec. Transmembrane voltage was optically recorded during application of the shock, simultaneously from 256 sites on a 11 × 11 mm area of the anterior right ventricular epicardium directly transmural to the distal electrode. The shock effect was evaluated by determining the difference between the AP affected by the shock and the normal AP. During cathodal stimulation an area of depolarization near the electrode was observed, surrounded by areas of hyperpolarization. The amplitude of polarization gradually decreased in areas far from the electrode. Inverting shock polarity reversed this effect. Conclusion: ICD monophasic defibrillation shocks create large dynamically interacting areas of both negative and positive polarization.
Electrocardiographic and Electrophysiologic Characterization of Atypical Atrial Flutter in Man:
Authors: KALMAN JONATHAN M. , OLGIN JEFFREY E. , SAXON LESLIE A. , LEE RANDALL J. , SCHEINMAN MELVIN M. , LESH MICHAEL D. 
Published: April 2007

Atypical Atrial Flutter. Introduction: Although the circuit in typical counterclockwise atrial flutter has been clearly delineated, the mechanisms of “atypical atrial flutters” have been less well characterized. The purpose of this study was to investigate the ECG and electrophysiologic (EP) characteristics of atypical atrial flutter. Methods and Results: Thirty‐three patients with at least one form of atypical atrial flutter underwent EP evaluation with multipolar atrial activation and entrainment mapping. Nineteen patients with clockwise flutter had: (1) stereotypic ECG morphology; (2) same cycle length as counterclockwise flutter; (3) clockwise activation around the tricuspid annulus; (4) recording of discrete split potentials along the length of the crista terminalis, suggesting the presence of conduction block; (5) concealed entrainment from the low right atrial isthmus; (6) successful ablation in this isthmus. Twenty patients with atypical flutter not consistent with a clockwise mechanism (“true atypical flutter”) showed: (1) heterogeneous ECG morphology; (2) cycle length shorter than that of clockwise flutter; (3) frequent transitions from and to atrial fibrillation; (4) could be entrained in only six patients and, when accomplished, demonstrated surface fusion when entraining from the low right atrial isthmus. Conclusions: Atypical flutter falls into two broad categories. Clockwise flutter uses the same circuit with the same endocardial barriers as its counterclockwise counterpart and is best con sidered a form of typical flutter. True atypical flutter induced in the EP laboratory is a hetero geneous group of arrhythmias that are transitional to atrial fibrillation. Although it may superficially resemble clockwise or counterclockwise flutter based on the 12‐lead ECG alone, the distinction can be readily made from a combined evaluation including activation and entrainment mapping.
The Zone of Vulnerability to T Wave Shocks in Humans
Authors: SWERDLOW CHARLES D. , MARTIN DAVID J. , KASS ROBERT M. , DAVIE SCOTT , MANDEL WILLIAM J. , GANG ELI S. , CHEN PENG‐SHENG 
Published: April 2007

Vulnerability to VF in Humans. Introduction: Shocks during the vulnerable period of the cardiac cycle induce ventricular fibrillation (VF) if their strength is above the VF threshold (VFT) and less than the upper limit of vulnerability (ULV). However, the range of shock strengths that constitutes the vulnerable zone and the corresponding range of coupling intervals have not been defined in humans. The ULV has been proposed as a measure of defibrillation because it correlates with the defibrillation threshold (DFT), but the optimal coupling interval for identifying it is unknown. Methods and Results: We studied 14 patients at implants of transvenous cardioverter defibrillators. The DFT was defined as the weakest shock that defibrillated after 10 seconds of VF. The ULV was defined as the weakest shock that did not induce VF when given at 0, 20, and 40 msec before the peak of the T wave or 20 msec after the peak in ventricular paced rhythm at a cycle length of 500 msec. The VFT was defined as the weakest shock that induced VF at any of the same four intervals. To identify the upper and lower boundaries of the vulnerable zone, we determined the shock strengths required to induce VF at all four intervals for weak shocks near the VFT and strong shocks near the ULV. The VFT was 72 ± 42 V, and the ULV was 411 ± 88 V. In all patients, a shock strength of 200 V exceeded the VFT and was less than the ULV. The coupling interval at the ULV was 19 ± 11 msec shorter than the coupling interval at the VFT (P < 0.001). The vulnerable zone showed a sharp peak at the ULV and a less distinct nadir at the VFT. A 20‐msec error in the interval at which the ULV was measured could have resulted in underestimating it by a maximum of 95 ± 31 V. The weakest shock that did not induce VF was greater for the shortest interval tested than for the longest interval at both the upper boundary (356 ± 108 V vs 280 ± 78 V; P < 0.01) and lower boundary (136 ± 68 msec vs 100 ± 65 msec; P < 0.05). Conclusions: The human vulnerable zone is not symmetric with respect to a single coupling interval, but slants from the upper left to lower right. Small differences in the coupling interval at which the ULV is determined or use of the coupling interval at the VFT to determine the ULV may result in significant variations in its measured value. An efficient strategy for inducing VF would begin by delivering a 200‐V shock at a coupling interval 10 msec before the peak of the T wave.
Mechanisms for Depolarization by I‐PalmitoyIcarnitine in Single Guinea Pig Ventricular Myocytes
Authors: SHEN JIAN‐BTNG , PAPPANO ACHILLES J 
Published: April 2007

I‐PC Inhibits INa/K and IK1 in Heart. introduction: The changes of the resting potential (RP) and of the current‐voltage (I‐V) relationship induced by l‐palmitoylcarnitine (I‐PC) in the presence of the IK1 blocker, cesium, or in the presence of the INa/K blocker, ouabain, were tested in guinea pig ventricular myocytes to ascertain the relative contributions of IK1 and INa/k suppression to the membrane depolarization caused by this amphiphile. Methods and Results: Ramp voltages were applied to myocytes with the whole cell, patch clamp technique. 1‐PC (10 μM) produced additional membrane depolarization in the presence of either 10 mM Cs+ or 30 μM ouabain. In the presence of Cs+ 1‐PC, like 3 μM ouabain, shifted current inward at potentials negative to ‐20 mV as a result of INa/K blockade. In the presence of 30 μM ouabain, 1‐PC, like Cs+, shifted current inward at potentials between ‐27 and ‐88 mV and outward at potentials negative to ‐88 mV. This is attributed to IK1 block because the current was inwardly rectifying, with a reversal potential near EK. When I‐PC or ouabain inhibited INa/K, the presence of an Ni2+‐sensitive component attributed to INa/ca distorted the membrane I‐V relationship, particularly in the presence of Cs+. The relative contributions of IK1 and INa/K block by 1‐PC were voltage dependent. At the RP, 1‐PC produced a greater block of INa/K than of IK1. Conclusion: I‐PC depolarizes the resting membrane by inhibiting both IK1 and INa/K. It is concluded that suppression of INa/K by I‐PC predominates over block of IK, to depolarize the membrane at the RP.
Upper Limit of Vulnerability Predicts Chronic Defibrillation Threshold for Transvenous Implantable Defibrillators
Authors: MARTIN DAVID J. , CHEN PENG‐SHENG , HWANG CHUN , GANG ELI S. , MANDEL WILLIAM J. , PETER C. THOMA , SWERDLOW CHARLES D. 
Published: April 2007

ULV Predicts Chronic DFT. Introduction: The upper limit of vulnerability (ULV) is the shock strength at or above which ventricular fibrillation cannot be induced when delivered in the vulnerable period. It correlates acutely with the acute defibrillation threshold (DFT) and can be determined with a single episode of fibrillation. The goal of this prospective study was to determine the relationship between the ULV and the chronic DFT. Methods and Results: We studied 40 patients at, and 3 months after, implantation of transvenous cardioverter defibrillators. The ULV was defined as the weakest biphasic shock that failed to induce fibrillation when delivered 0,20, and 40 msec before the peak of the T wave. Patients were classified as clinically stable or unstable based on prospectively defined criteria. There were no significant differences between the group means for the acute and chronic determinations of ULV (13.5 ± 5.3 J vs 12.4 ± 6.8 J, P = 0.25) and DFT (10.1 ± 5.0 J vs 9.9 ± 5.7 J, P = 0.74). Five patients (15%) were classified as unstable. The strength of the correlation between acute ULV and acute DFT (r = 0.74, P < 0.001) was similar to that between the chronic ULV and chronic DFT (r = 0.82, P < 0.001). There was a correlation between the change in ULV from acute to chronic and the corresponding change in DFT (r = 0.67, P < 0.001). The chronic DFT was less than the acute ULV + 3 J in all 35 stable patients, but it was greater in 2 of 5 unstable patients (P = 0.04). Conclusions: The strength of the correlation between the chronic ULV and the chronic DFT is comparable to that between the acute ULV and the acute DFT. Temporal changes in the ULV predict temporal changes in the DFT. In clinically stable patients, a defibrillation safety margin of 3 J above the acute ULV proved an adequate chronic safety margin.