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Accurate Indicator (accurate + indicator)
Selected AbstractsElectrogram Polarity and Cavotricuspid Isthmus Block During Ablation of Typical Atrial FlutterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2001HIROSHI TADA M.D. Electrogram Polarity in Atrial Flutter Ablation.Introduction: The atrial activation sequence around the tricuspid annulus has been used to assess whether complete block has been achieved across the cavotricuspid isthmus during radiofrequency ablation of typical atrial flutter. However, sometimes the atrial activation sequence does not clearly establish the presence or absence of complete block. The purpose of this study was to determine whether a change in the polarity of atrial electrograms recorded near the ablation line is an accurate indicator of complete isthmus block. Methods and Results: Radiofrequency ablation was performed in 34 men and 10 women (age 60 ± 13 years [mean ± SD]) with isthmus-dependent, counterclockwise atrial flutter. Electrograms were recorded around the tricuspid annulus using a duodecapolar halo catheter. Electrograms recorded from two distal electrode pairs (E1 and E2) positioned just anterior to the ablation line were analyzed during atrial flutter and during coronary sinus pacing, before and after ablation. Complete isthmus block was verified by the presence of widely split double electrograms along the entire ablation line. Complete bidirectional isthmus block was achieved in 39 (89%) of 44 patients. Before ablation, the initial polarity of E1 and E2 was predominantly negative during atrial flutter and predominantly positive during coronary sinus pacing. During incomplete isthmus block, the electrogram polarity became reversed either only at E2, or at neither E1 nor E2. In every patient, the polarity of E1 and E2 became negative during coronary sinus pacing only after complete isthmus block was achieved. In 4 patients (10%), the atrial activation sequence recorded with the halo catheter was consistent with complete isthmus block, but the presence of incomplete block was accurately detected by inspection of the polarity of E1 and E2. Conclusion: Reversal of polarity in bipolar electrograms recorded just anterior to the line of isthmus block during coronary sinus pacing after ablation of atrial flutter is a simple, quick, and accurate indicator of complete isthmus block. [source] Bias in cross-validated free R factors: mitigation of the effects of non-crystallographic symmetryACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2006Felcy Fabiola Current methods of free R factor cross-validation assume that the structure factors of the test and working sets are independent of one another. This assumption is only an approximation when the modeled structure occupies anything less than the full asymmetric unit. Through progressive elimination of reflections from the working set, starting with those expected to be most correlated to the test set, small biases in free R can be measured, presumably because of over-sampling of the Fourier transform owing to bulk solvent in the crystal. This level of bias may be of little practical importance, but it rises to significant levels with increasing non-crystallographic symmetry owing to wider correlations between structure factors than hitherto appreciated. In the presence of 15-fold non-crystallographic symmetry, with resolutions commonly attainable in macromolecular crystallography, it may not be possible to calculate an unbiased free R factor. Methods are developed for the calculation of reduced-bias free R factors through elimination of the strongest correlations between test and working sets. With 180-fold non-crystallographic symmetry they may not be an accurate indicator of absolute quality, but they do yield the correct optimal weighting for stereochemical restraints. [source] Update on intrapartum fetal pulse oximetryAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2002Christine E East ABSTRACT This article examines the current status of fetal pulse oximetry (FPO) as a means of intrapartum assessment of fetal wellbeing. FPO has been developed to a stage where it is a safe and accurate indicator of intrapartum fetal oxygenation. In general, sliding the FPO sensor along the examiner's fingers and through the cervix, to lie alongside the fetal cheek or temple is easy. The recent publication of a randomized controlled trial (RCT) of FPO versus conventional intrapartum monitoring has validated its use to reduce caesarean section rates for nonreassuring fetal status. An Australian multicentre RCT is currently underway. Maternal satisfaction rates with FPO are high. FPO may be used during labour when the electronic fetal heart rate trace is nonreassuring or when conventional monitoring is unreliable, such as with fetal arrhythmias. If the fetal oxygen saturation (FSpO2) values are < 30%, prompt obstetric intervention is indicated, such as fetal scalp blood sampling or delivery. FSpO2 monitoring should not form the sole basis of intrapartum fetal welfare assessment. Rather, the whole clinical picture should be considered. [source] The Benefits of Banking Mega-Mergers: Event Study Evidence from the 1998 Failed Mega-Merger Attempts in CanadaCANADIAN JOURNAL OF ADMINISTRATIVE SCIENCES, Issue 3 2003Ramon Baltazar We investigate the main benefit(s) of specific banking mega-mergers, and whether or not we can infer the benefit(s) from event study evidence of stock market reactions to the mega-mergers. In addressing these questions, we examine the market's reactions to three announcements surrounding the 1998 failed mega-merger attempts in the Canadian banking industry. From our analysis, we conclude that market power,not scale, scope, or X-eficiency economies, or access to government safety net subsidies,was the primary benefit ascribed by Canadian shareholders to the merger proposals. To the extent that the market's perception of merger benefits is an accurate indicator of the merging partners' motives, we also conclude that an analysis of shareholder reactions to a merger announcement,as undertaken here,is a productive avenue for regulators attempting to discern a particular merger's main motivations. Résumé Dans cette étude, nous examinons les avantages principaux de certaines méga-fusions bancaires. Nous nous demandons s'il est possible d'inférer ces avantages à partir de l'étude des réactions du marché boursier aux méga-fusions. Notre étude s'appuie sur les réactions du marché enregistrées à la suite de trois annonces, en 1998, de tentatives de méga-fusions avortées dans l'industrie bancaire canadienne. Notre analyse débouche sur la conclusion que le pouvoir du marché,et non son échelle, son étendue, l'efficacité de son économie (économies en efficacité X) ou l'accès au filet de sécurité des subventions gouvernementales,est le principal avantage que les actionnaires canadiens évoquent pour justifier les propositions de fusion. La perception des avantages de la fusion étant un indicateur clair des motivations des partenaires de la fusion, nous pensons qu'une analyse des réactions des actionnaires à l'annonce d'une fusion est une piste pertinente dans la détermination des principales raisons qui la sous-tendent. [source] How Consistently are Good Parents Good Parents?ETHOLOGY, Issue 4 2003Passer domesticus, Repeatability of Parental Care in the House Sparrow In many avian species, substantial individual variation occurs in parental food-provisioning levels, which often is assumed to reflect variation in parental quality. Parental quality also has often been invoked as a key element in mate choice among biparental species, and many sexually-selected traits have been investigated as potential predictors of parental quality. In recent studies of house sparrow (Passer domesticus) parents, we found that individuals behaved remarkably consistently across time, regardless of temporary manipulations of the nestling provisioning of their partners. This suggests that variation in parental competence may be attributable to quality differences among individuals. One prediction of the ,parental quality differences' hypothesis is that individuals also should show consistency in their provisioning behavior across broods. To test this, we compared the parental delivery rates of individual house sparrows across broods. Parents of both sexes reduced their per-chick delivery rates as the season progressed; parents of both sexes were also responsive to changes in their brood sizes. Despite these sources of environmental variation in provisioning rates, the parental care of individual males was highly repeatable across broods. By contrast, female parental care showed extremely low repeatability, and standardized measures of among-individual variation in parental behavior revealed females to be much less variable than males. These results indicate that females in this multi-brooded species have much to gain from mate-choice decisions predicated on male parental quality or accurate indicators of such, whereas males are less likely to profit from being highly selective about the ,parental quality' of their partners. [source] | ||||||||||