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High Threshold (high + threshold)
Selected AbstractsLocalization of KCNC1 (Kv3.1) potassium channel subunits in the avian auditory nucleus magnocellularis and nucleus laminaris during developmentDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2003Suchitra Parameshwaran-Iyer Abstract The KCNC1 (previously Kv3.1) potassium channel, a delayed rectifier with a high threshold of activation, is highly expressed in the time coding nuclei of the adult chicken and barn owl auditory brainstem. The proposed role of KCNC1 currents in auditory neurons is to reduce the width of the action potential and enable neurons to transmit high frequency temporal information with little jitter. Because developmental changes in potassium currents are critical for the maturation of the shape of the action potential, we used immunohistochemical methods to examine the developmental expression of KCNC1 subunits in the avian auditory brainstem. The KCNC1 gene gives rise to two splice variants, a longer KCNC1b and a shorter KCNC1a that differ at the carboxy termini. Two antibodies were used: an antibody to the N-terminus that does not distinguish between KCNC1a and b isoforms, denoted as panKCNC1, and another antibody that specifically recognizes the C terminus of KCNC1b. A comparison of the staining patterns observed with the panKCNC1 and the KCNC1b specific antibodies suggests that KCNC1a and KCNC1b splice variants are differentially regulated during development. Although panKCNC1 immunoreactivity is observed from the earliest time examined in the chicken (E10), a subcellular redistribution of the immunoproduct was apparent over the course of development. KCNC1b specific staining has a late onset with immunostaining first appearing in the regions that map high frequencies in nucleus magnocellularis (NM) and nucleus laminaris (NL). The expression of KCNC1b protein begins around E14 in the chicken and after E21 in the barn owl, relatively late during ontogeny and at the time that synaptic connections mature morphologically and functionally. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 165,178, 2003 [source] On the ecology of the rotifer Cephalodella hoodi from an extremely acidic lakeFRESHWATER BIOLOGY, Issue 9 2005GUNTRAM WEITHOFF Summary 1.,The biovolume-specific carbon content, relative egg volume (a measure of per-offspring reproductive investment), growth and grazing rates, and the gross growth efficiency (GGE) of the rotifer Cephalodella hoodi, isolated from an extremely acidic habitat (pH 2.65), were determined and compared with literature values for rotifers living in circum-neutral habitats in order to reveal potential special features or adaptations related to the extreme habitat of C. hoodi. 2.,Of the two dominant phytoflagellates (Ochromonas sp. and Chlamydomonas acidophila) that occur in the natural habitat of C. hoodi, only C. acidophila promoted positive growth and reproduction and, thus, the following results were obtained with C. acidophila as a food alga. 3.,The body volume-specific carbon content of C. hoodi is in the range of that found in rotifers from circum-neutral lakes, suggesting that no costly carbon investment, brought about by the thickening of the lorica, for example, was required to withstand low pH. 4.,The egg volume of C. hoodi exhibited no phenotypic plasticity dependent on the food concentration and, thus, C. hoodi allocated a constant, absolute amount of energy to each individual offspring. No adaptation to low food densities was found. 5.,A dome-shaped type II functional response curve was found to describe the ingestion of Chlamydomonas as a source of food. 6.,Compared with other rotifers, C. hoodi had a high threshold and half-saturating food concentration (=low affinity) but also a high maximum growth rate and a relatively high GGE, suggesting no severe adverse effect of low pH. [source] Detection thresholds of capsaicin: a new test to assess facial skin neurosensitivityINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2005R. Jourdain The goal of this study was to assess the accuracy/reliability of a new test designed to measure cutaneous neurosensitivity. The test was carried out on a random population of 150 healthy adult women and was based on the determination of individual detection thresholds of topically applied capsaicin. Five capsaicin concentrations were used in 10% ethanol aqueous solution (3.16 × 10,5%; 1 × 10,4%; 3.16 × 10,4%; 1 × 10,3%; 3.16 × 10,3%). The methodology used to attain the detection threshold was capsaicin application in increasing concentration on the nasolabial folds. The vehicle was simultaneously applied following a split-face, single-blind plan. The test was stopped as soon as the subject reported a specific sensation lasting more than 30 s on the capsaicin side. The safety of the test was judged as excellent by the panellists since all the reported sensations were considered as slightly or moderately perceptible. The test allowed the classification of the test population according to six threshold levels corresponding to the sensitive reaction to one of the five capsaicin concentrations and to the absence of sensitivity to the highest concentration. Surprisingly, the distribution of the population was not unimodal and seemed to reveal the existence of two different sub-groups: individuals with a low capsaicin detection threshold and those with a high threshold. These two sub-populations strongly differed in their respective self-perception of sensitive skin. The higher the self-declared sensitive skin incidence was, the lower the detection threshold was. This new test of skin neurosensitivity is easy, quick, and truly painless. It appears to be a promising tool for the cosmetic diagnosis of sensitive skin. [source] Inference for clusters of extreme valuesJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 2 2003Christopher A. T. Ferro Summary. Inference for clusters of extreme values of a time series typically requires the identification of independent clusters of exceedances over a high threshold. The choice of declustering scheme often has a significant effect on estimates of cluster characteristics. We propose an automatic declustering scheme that is justified by an asymptotic result for the times between threshold exceedances. The scheme relies on the extremal index, which we show may be estimated before declustering, and supports a bootstrap procedure for assessing the variability of estimates. [source] Self-inflicted bodily harm among victims of intimate-partner violenceCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 5 2007Randy A. Sansone In this study, we surveyed 113 women psychiatric inpatients with regard to histories of intimate-partner violence and six self-harm behaviours related to the intentional damage of one's body (e.g., cutting, hitting, scratching self). Multiple regression analysis revealed that a history of domestic violence was a statistically significant predictor of bodily self-harm even after controlling for age and having ever been married. Among some victims of domestic violence, this statistical relationship may indicate an underlying common psychodynamic theme such as a high threshold for body maltreatment and/or low body esteem. Regardless, these data suggest that mental health clinicians need to explore among women victims of intimate-partner violence the presence of self-initiated bodily self-harm.,Copyright © 2007 John Wiley & Sons, Ltd. [source] Future-biased search: the quest for the idealJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 4 2008Suzanne B. Shu Abstract Decision-makers with ideal candidates already in mind often extend search beyond optimal endpoints when searching for the best option among a sequential list of alternatives. Extended search is investigated here using three laboratory experiments; individuals in these tasks exhibit future-bias, delaying choice beyond normative benchmarks. Searchers' behavior is consistent with setting high thresholds based on a focal ideal outcome without full attention to its probability or the value of second-best alternatives; the behavior is partially debiased by manipulating which outcomes are in the searchers' focal set. Documenting future-bias in sequential search tasks offers new insights for understanding self-control and intertemporal choice by providing a situation in which thresholds may be set too high and myopic behavior does not prevail. Copyright © 2008 John Wiley & Sons, Ltd. [source] Programmable Multiple Pacing Configurations Help to Overcome High Left Ventricular Pacing Thresholds and Avoid Phrenic Nerve StimulationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2005OSNAT GUREVITZ Background: High left ventricular pacing (LVP) thresholds and phrenic nerve stimulation (PNS) are common problems with cardiac resynchronization (CRT). Newer systems capable of multiple LVP configurations may help overcome these problems without the need for reoperation. Methods: CRT systems capable of multiple LVP configurations (Guidant models H155 and H145) were implanted in 43 patients (study group). An additional 49 patients (control group) received CRT systems (Guidant, Medtronic, Biotronik, St. Jude Medical, various models) lacking this feature. Results: Overall, acute high (,2.5 V/0.5 ms) LVP thresholds were encountered in 13 (30%) of the study group, and 25 (50%) of control group patients (P = 0.03). PNS was encountered in 5 (12%) of the study group and 12 (24%) of control group patients (P = 0.13). All cases of high LVP thresholds and PNS in the study group were managed by switching to a different LVP configuration, while high thresholds remained in control group patients, and PNS was managed by replacing the lead. The CS lead was successfully placed in a lateral branch in 95% of study group, compared to only 77% of control group patients (P = 0.004). Conclusions: Multiple LVP configurations were clinically useful in a significant number of patients undergoing CRT system implantation by helping to overcome high LVP thresholds and PNS, and by providing more flexibility in placing the LV lead. [source] Clinical Predictors of Defibrillation Thresholds with an Active Pectoral Pulse Generator Lead SystemPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2002DENICE M. HODGSON HODGSON, D.M., et al.: Clinical Predictors of Defibrillation Thresholds with an Active Pectoral Pulse Generator Lead System. Active pectoral pulse generators are used routinely for initial ICD placement because they reduce DFTs and simplify the implantation procedure. Despite the common use of these systems, little is known regarding the clinical predictors of defibrillation efficacy with active pulse generator lead configurations. Such predictors would be helpful to identify patients likely to require higher output devices or more complicated implantations. This was a prospective evaluation of DFT using a uniform testing protocol in 102 consecutive patients with an active pectoral can and dual coil transvenous lead. For each patient, the DFT was measured with a step-down protocol. In addition, 34 parameters were assessed including standard clinical echocardiographic and radiographic measures. Multivariate stepwise regression analysis was performed to identify independent predictors of the DFT. The mean DFT was 9.3 ± 4.6 J and 93% (95/102) of patients had a DFT , 15 J. The QRS duration, interventricular septum thickness, left ventricular mass, and mass index were significant but weak (R < 0.3) univariate predictors of DFT. The left ventricular mass was the only independent predictor by multivariate analysis, but this parameter accounted for < 5% of the variability of DFT measured (adjusted R2= 0.047, P = 0.017). The authors concluded that an acceptable DFT (< 15 J) is observed in > 90% of patients with this dual coil and active pectoral can lead system. Clinical factors are of limited use for predicting DFTs and identifying those patients who will have high thresholds. [source] Managing sexually abused and/or abusing children in substitute careCHILD & FAMILY SOCIAL WORK, Issue 2 2003Elaine Farmer ABSTRACT This paper reports on research on the characteristics, management and therapeutic treatment of sexually abused and/or abusing children in substitute care. Of the 40 sexually abused and/or abusing young people aged 10 or over in the interview sample, two-thirds showed sexual behaviours in the placement studied but one-third did not. The range of sexual behaviours shown by the young people is described. Analysis of the findings shows that four key components of effective management are supervision, adequate sex education, modification of inappropriate sexual behaviour and therapeutic attention to the needs that underlie such behaviour. Supervision includes planning for safe care before placement, preparing other children in the setting, teaching young people how to keep themselves safe when out on their own, and careful monitoring of contact with birth family members. The need for a proactive approach to sex education is stressed. Effective management approaches to masturbation, sexualized behaviour and sexually abusing behaviour are discussed but the processes of denial and minimization of sexual abuse and the development of high thresholds for action when looked after children are abused or at risk are shown to present obstacles to effective care. Finally, the importance of addressing children's deeper needs is emphasized, including the importance of regular review of their need for counselling. At the end of the article two case examples from the study are given. [source] | |||||||||||||