Effect of Surface Electrode Number on Estimates of Cardiac Dipole Moment

This study reports on the errors in the calculation of a heart dipole introduced by deleting individual electrode contributions to a surface potential map. The potential at 150 points on each of 6 normal children was available at several instants of the QRS cycle. Although it was impossible to test all possible sets of deleted points, or all possible methods of compensatory weighting of the residual points, the results indicate that a number of electrodes at least as great as 100 is required to produce consistent relative errors of less than 15 percent, if surface potential integration is employed in determining the heart's total dipole moment.     

Computer-based engineering of thermostabilized antibody fragments

We used the molecular modeling program Rosetta to identify clusters of amino acid substitutions in antibody fragments (scFvs and scAbs) that improve global protein stability and resistance to thermal deactivation. Using this methodology, we increased the melting temperature (T_m) and resistance to heat treatment of an antibody fragment that binds to the Clostridium botulinum hemagglutinin protein (anti-HA33). Two designed antibody fragment variants with two amino acid replacement clusters, designed to stabilize local regions, were shown to have both higher T_m compared to the parental scFv and importantly to retain full antigen binding activity after 2 hr of incubation at 70°C. The crystal structure of one thermostabilized scFv variants was solved at 1.6 Å and shown to be in close agreement with the RosettaAntibody model prediction.     

Hypothalamic and midbrain neural pathways involved in eating, drinking, irritability, aggression, and copulation in rats.

Investigated in 3 experiments with male hooded rats (N = 61) the effects of parasagittal cuts placed at 3 anterior-posterior positions. Cuts that separated portions of the medial from the lateral hypothalamus produced severe hyposexuality if they lay lateral to the medial preoptic-anterior hypothalamic continuum. Hyperphagia, irritability, and modest sexual impairment were produced if the cuts lay lateral to the anterior tips of the ventromedial hypothalamic nuclei and slightly invaded the anterior hypothalamus. Posterior, but not anterior, medial-forebrain-bundle (MFB) cuts disrupted copulation. Central gray cuts resulted in slight hyperphagia, and reticular formation cuts resulted in hyposexuality. It is concluded that the medial hypothalamic nuclei exert their effects on eating, irritability, and copulation through their lateral connections with the lateral hypothalamus and those components of the MFB that descend on (or ascend from) the lower brainstem. (40 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory self-efficacy and performance differences in young and old adults: The effect of mnemonic training.

We evaluated the hypothesis that mnemonic training would result in higher memory self-efficacy and better memory performance in young and old adults. Forty-eight young adults (17- to 19-year-olds) and 45 old adults (60- to 78-year-olds) received either training in the method of loci or no training and were given either performance feedback or no feedback on a serial-word recall task. Ss were tested at pre- and posttraining and were asked to rate their self-efficacy strength (SEST) and self-efficacy level (SEL) at each test session. Young adults recalled more than old adults and had higher self-efficacy scores. Training with feedback improved recall performance in both age groups but failed to increase SEST or SEL. When SEL scores were used to derive a measure of prediction inaccuracy, no age differences were observed. We conclude that efficacy expectations and attributions for memory performance may influence mnemonic training outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simple computational model for analyzing the properties of stop-loss,take-profit,and price breakout trading strategies

Stop-loss, take profit and price breakout strategies, though in some ways theoretically unattractive, are nonetheless popular with traders. We describe and illustrate a simple, fast, flexible and practical discrete time computational model for performing probabilistic analyses of the risks, rewards and tradeoffs associated such strategies.     

Contribution of nesting experience to progesterone-induced incubation in ring doves (Streptopelia risoria).

Examined whether exposure of 60 ring doves to progesterone during the nest-building phase would be sufficient to account for the ability of progesterone to induce incubation at a later time or whether some other factor provided by nest-building experience with this phase of the cycle would be needed. Six groups of 10 pairs of Ss each were provided with different combinations of experience and progesterone priming. Progesterone priming (100 μg for 4 days), combined with social isolation or with courtship experience, had no significant effect on subsequent progesterone-induced incubation. However, Ss that participated in the nesting phase of the cycle during progesterone priming later incubated in response to progesterone treatment. Nesting activity, which did or did not include building the nest, seemed to be the relevant experience. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An epidemiological needs assessment of carotid endarterectomy in an English health region. Is the need being met?

OBJECTIVE: To compare the level of provision of carotid endarterectomy (an intervention of proved efficacy for prevention of stroke in patients with symptomatic high grade carotid artery stenosis) with estimates of need. DESIGN: Comparison of regional, district, and age-sex specific operation rates derived from hospital episode statistics with estimates of need based on demographic and epidemiological data; interviews with regional vascular surgeons and a joint provider-purchaser workshop to discuss implications. SETTING: Former Wessex Regional Health Authority, 1991-2 to 1995-6. SUBJECTS: All residents covered by Wessex region treated for carotid artery reconstruction. MAIN OUTCOME MEASURES: Regional, district, and age-sex operation rates as three year average 1993-6 (use) compared with respective estimates of need for carotid endarterectomy among those who presented with symptomatic carotid disease-transient ischaemic attack or minor stroke. RESULTS: The operation rate more than doubled between 1991-2 and 1995-6, from 35 to 89 per million population, compared with an estimated level of need in the region's general population of 153 per million population (transient ischaemic attack 77, minor stroke 76). The ratio of use to need was 0.47 (95% confidence interval 0.4 to 0.54); district ratios were 0.28 (0.19-0.38) to 0.81 (0.62 to 1.06). The annual use:need ratio rose over the three years 1993-6 from 0.38 to 0.59. Use:need ratios were lower in elderly and female patients. Providers were keen to develop guidelines for referral and to increase access to diagnostic facilities; purchasers were more reluctant, given the limited impact of this intervention on the incidence of stroke and the relatively high cost of the operation. CONCLUSION: Although treatment rates increased in Wessex there is still unmet need. Further research is needed to determine the referral pathways of patients with symptomatic carotid disease for diagnosis and operation and to evaluate strategies to improve access to diagnostic facilities.