Impaired performance on the rapid visual information processing task (RVIP) could be an endophenotype of schizophrenia

The aim of the present study was to investigate whether healthy first-degree relatives of schizophrenia patients show reduced sensitivity performance, higher intra-individual variability (IIV) in reaction time (RT), and a steeper decline in sensitivity over time in a sustained attention task. Healthy first-degree relatives of schizophrenia patients (n=23) and healthy control subjects (n=46) without a family history of schizophrenia performed a demanding version of the Rapid Visual Information Processing task (RVIP). RTs, hits, false alarms, and the sensitivity index A' were assessed. The relatives were significantly less sensitive, tended to have higher IIV in RT, but sustained the impaired level of sensitivity over time. Impaired performance on the RVIP is a possible endophenotype for schizophrenia. Higher IIV in RT, apparently caused by impaired context representations, might result in fluctuations in control and lead to more frequent attentional lapses.

Shear band evolution in Zr/Hf-based bulk metallic glasses under static and dynamic indentations

Bulk metallic glasses (BMGs) exhibit superior mechanical properties as compared with other conventional materials and have been proposed for numerous engineering and technological applications. Zr/Hf-based BMGs or tungsten reinforced BMG composites are considered as a potential replacement for depleted uranium armor-piercing projectiles because of their ability to form localized shear bands during impact, which has been known to be the dominant plastic deformation mechanism in BMGs. However, in conventional tensile, compressive and bending tests, limited ductility has been observed because of fracture initiation immediately following the shear band formation. To fully investigate shear band characteristics, indentation tests that can confine the deformation in a limited region have been pursued. In this thesis, a detailed investigation of thermal stability and mechanical deformation behavior of Zr/Hf-based BMGs is conducted. First, systematic studies had been implemented to understand the influence of relative compositions of Zr and Hf on thermal stability and mechanical property evolution. Second, shear band evolution under indentations were investigated experimentally and theoretically. Three kinds of indentation studies were conducted on BMGs in the current study. (a) Nano-indentation to determine the mechanical properties as a function of Hf/Zr content. (b) Static Vickers indentation on bonded split specimens to investigate the shear band evolution characteristics beneath the indention. (c) Dynamic Vickers indentation on bonded split specimens to investigate the influence of strain rate. It was found in the present work that gradually replacing Zr by Hf remarkably increases the density and improves the mechanical properties. However, a slight decrease in glass forming ability with increasing Hf content has also been identified through thermodynamic analysis although all the materials in the current study were still found to be amorphous. Many indentation studies have revealed only a few shear bands surrounding the indent on the top surface of the specimen. This small number of shear bands cannot account for the large plastic deformation beneath the indentations. Therefore, a bonded interface technique has been used to observe the slip-steps due to shear band evolution. Vickers indentations were performed along the interface of the bonded split specimen at increasing loads. At small indentation loads, the plastic deformation was primarily accommodated by semi-circular primary shear bands surrounding the indentation. At higher loads, secondary and tertiary shear bands were formed inside this plastic zone. A modified expanding cavity model was then used to predict the plastic zone size characterized by the shear bands and to identify the stress components responsible for the evolution of the various types of shear bands. The applicability of various hardness—yield-strength ( H −σγ ) relationships currently available in the literature for bulk metallic glasses (BMGs) is also investigated. Experimental data generated on ZrHf-based BMGs in the current study and those available elsewhere on other BMG compositions were used to validate the models. A modified expanding-cavity model, employed in earlier work, was extended to propose a new H −σγ relationship. Unlike previous models, the proposed model takes into account not only the indenter geometry and the material properties, but also the pressure sensitivity index of the BMGs. The influence of various model parameters is systematically analyzed. It is shown that there is a good correlation between the model predictions and the experimental data for a wide range of BMG compositions. Under dynamic Vickers indentation, a decrease in indentation hardness at high loading rate was observed compared to static indentation hardness. It was observed that at equivalent loads, dynamic indentations produced more severe deformation features on the loading surface than static indentations. Different from static indentation, two sets of widely spaced semi-circular shear bands with two different curvatures were observed. The observed shear band pattern and the strain rate softening in indentation hardness were rationalized based on the variations in the normal stress on the slip plane, the strain rate of shear and the temperature rise associated with the indentation deformation. Finally, a coupled thermo-mechanical model is proposed that utilizes a momentum diffusion mechanism for the growth and evolution of the final spacing of shear bands. The influence of strain rate, confinement pressure and critical shear displacement on the shear band spacing, temperature rise within the shear band, and the associated variation in flow stress have been captured and analyzed. Consistent with the known pressure sensitive behavior of BMGs, the current model clearly captures the influence of the normal stress in the formation of shear bands. The normal stress not only reduces the time to reach critical shear displacement but also causes a significant temperature rise during the shear band formation. Based on this observation, the variation of shear band spacing in a typical dynamic indentation test has been rationalized. The temperature rise within a shear band can be in excess of 2000K at high strain rate and high confinement pressure conditions. The associated drop in viscosity and flow stress may explain the observed decrease in fracture strength and indentation hardness. The above investigations provide valuable insight into the deformation behavior of BMGs under static and dynamic loading conditions. The shear band patterns observed in the above indentation studies can be helpful to understand and model the deformation features under complex loading scenarios such as the interaction of a penetrator with armor. Future work encompasses (1) extending and modifying the coupled thermo-mechanical model to account for the temperature rise in quasistatic deformation; and (2) expanding this model to account for the microstructural variation-crystallization and free volume migration associated with the deformation.

Caloric vestibular stimulation modulates affective control and mood

BACKGROUND: Clinical evidence suggests a link between vestibular dysfunctions and mood disorders. No study has yet investigated mood and affective control during vestibular stimulation in healthy participants. OBJECTIVE: We predicted a modulating effect of caloric vestibular stimulation (CVS) on affective control measured in an affective Go/NoGo task (AGN). METHODS: Thirty-two participants performed an AGN task while they were exposed to cold left or right ear CVS (20 °C) and sham stimulation (37 °C). In each block, either positive or negative pictures (taken from the International Affective Picture System) were defined as targets. Participants had to respond to targets (Go), and withhold responses to distractors (NoGo). RESULTS: The sensitivity index d' (hits - false alarms) was used to measure affective control. Affective control improved during right ear CVS when viewing positive stimuli (P = .005), but decreased during left ear CVS when compared to sham stimulation (P = .009). CVS had a similar effect on positive mood ratings (Positive and Negative Affect Schedule). Positive mood ratings decreased during left ear CVS when compared to sham stimulation, but there was no effect after right ear CVS. DISCUSSION: The results suggest that CVS, depending on side of stimulation, has a modulating effect on mood and affective control. The results complement previous findings in manic patients and provide new evidence for the clinical potential of CVS.

Is depression associated with insulin resistance? A systematic review

Studies suggest that depression affects glucose metabolism, and therefore is a risk factor for insulin resistance. The association between depression and insulin resistance has been investigated in a number of studies, but there is no agreement on the results. The objective of this study is to survey the epidemiological studies, identify the ones that measured the association of depression (as exposure) with insulin resistance (as outcome), and perform a systematic review to assess the reliability and strength of the association. For high quality reporting, and assessment, this systematic review used the outlined procedures, guidelines and recommendations for reviews in health care, suggested by the Centre for Reviews and Dissemination, along with recommendations from the STROBE group (Strengthening the Reporting of Observational Studies in Epidemiology). Ovid MEDLINE 1996 to April Week 1 2010, was used to identify the relevant epidemiological studies. To identify the most relevant set of articles for this systematic review, a set of inclusion and exclusion criteria were applied. Six studies that met the specific criteria were selected. Key information from identified studies was tabulated, and the methodological quality, internal and external validity, and the strength of the evidence of the selected studies were assessed. The result from the tabulated data of the reviewed studies indicates that the studies either did not apply a case definition for insulin resistance in their investigation, or did not state a specific value for the index used to define insulin resistance. The quality assessment of the reviewed studies indicates that to assess the association between insulin resistance and depression, specifying a case definition for insulin resistance is important. The case definition for insulin resistance is defined by the World Health Organization and the European Group for the Study of Insulin Resistance as the insulin sensitivity index of the lowest quartile or lowest decile of a general population, respectively. Three studies defined the percentile cut-off point for insulin resistance, but did not give the insulin sensitivity index value. In these cases, it is not possible to compare the results. Three other studies did not define the cut-off point for insulin resistance. In these cases, it is hard to confirm the existence of insulin resistance. In conclusion, to convincingly answer our question, future studies need to adopt a clear case definition, define a percentile cut-off point and reference population, and give value of the insulin resistance measure at the specified percentile.^

Macrofauna biodiversity from ECO2 water-formation experiment

The injection of gas into sub-seabed aquifers may lead to the displacement of hypoxic and hypersaline fluids (reservoir formation water) major environmental risk. To investigate this risk, the impact of formation water release on the macrofaunal community in a mesocosm experiment at Solbergstrand was conducted. 20 boxcores were exposed to 4 treatments (high salinity, hypoxic, mixed and tidal) during two weeks. The abundance of macrofauna was quantified for each treatment and richness, eveness and biodiversity indices calculated. The data are reported in this dataset.

A compilation of the messages and papers of the presidents, 1789-1902 /

v. 1. 1789-1817 -- v. 2. 1817-1833 -- v. 3. 1833-1841 -- v. 4. 1841-1849 -- v. 5. 1849-1861 -- v. 6. 1861-1869 -- v. 7. 1869-1881 -- v. 8. 1881-1889 -- v. 9. 1889-1897 -- v. 10. 1897-1902 -- Index / revised and enlarged by George Raywood Devitt.

A history of Amherst College during the administrations of its first five presidents : from 1821 to 1891 /

Includes index.

Sampling times for monitoring tacrolimus in stable adult liver transplant recipients

The aim of this study was to determine the most informative sampling time(s) providing a precise prediction of tacrolimus area under the concentration-time curve (AUC). Fifty-four concentration-time profiles of tacrolimus from 31 adult liver transplant recipients were analyzed. Each profile contained 5 tacrolimus whole-blood concentrations (predose and 1, 2, 4, and 6 or 8 hours postdose), measured using liquid chromatography-tandem mass spectrometry. The concentration at 6 hours was interpolated for each profile, and 54 values of AUC(0-6) were calculated using the trapezoidal rule. The best sampling times were then determined using limited sampling strategies and sensitivity analysis. Linear mixed-effects modeling was performed to estimate regression coefficients of equations incorporating each concentration-time point (C0, C1, C2, C4, interpolated C5, and interpolated C6) as a predictor of AUC(0-6). Predictive performance was evaluated by assessment of the mean error (ME) and root mean square error (RMSE). Limited sampling strategy (LSS) equations with C2, C4, and C5 provided similar results for prediction of AUC(0-6) (R-2 = 0.869, 0.844, and 0.832, respectively). These 3 time points were superior to C0 in the prediction of AUC. The ME was similar for all time points; the RMSE was smallest for C2, C4, and C5. The highest sensitivity index was determined to be 4.9 hours postdose at steady state, suggesting that this time point provides the most information about the AUC(0-12). The results from limited sampling strategies and sensitivity analysis supported the use of a single blood sample at 5 hours postdose as a predictor of both AUC(0-6) and AUC(0-12). A jackknife procedure was used to evaluate the predictive performance of the model, and this demonstrated that collecting a sample at 5 hours after dosing could be considered as the optimal sampling time for predicting AUC(0-6).

An integrated cognitive model of panic disorder: The role of positive and negative cognitions

One reason for the neglect of the role of positive factors in cognitive-behavioural therapy (CBT) may relate to a failure to develop cognitive models that integrate positive and negative cognitions. Bandura [Psychol. Rev. 84 (1977) 191; Anxiety Res. 1 (1988) 77] proposed that self-efficacy beliefs mediate a range of emotional and behavioural outcomes. However, in panic disorder, cognitively based research to date has largely focused on catastrophic misinterpretation of bodily sensations. Although a number of studies support each of the predictions associated with the account of panic disorder that is based on the role of negative cognitions, a review of the literature indicated that a cognitively based explanation of the disorder may be considerably strengthened by inclusion of positive cognitions that emphasize control or coping. Evidence to support an Integrated Cognitive Model (ICM) of panic disorder was examined and the theoretical implications of this model were discussed in terms of both schema change and compensatory skills accounts of change processes in CBT. (C) 2004 Elsevier Ltd. All rights reserved.

Acute administration of unacylated ghrelin has no effect on Basal or stimulated insulin secretion in healthy humans.

Unacylated ghrelin (UAG) is the predominant ghrelin isoform in the circulation. Despite its inability to activate the classical ghrelin receptor, preclinical studies suggest that UAG may promote β-cell function. We hypothesized that UAG would oppose the effects of acylated ghrelin (AG) on insulin secretion and glucose tolerance. AG (1 µg/kg/h), UAG (4 µg/kg/h), combined AG+UAG, or saline were infused to 17 healthy subjects (9 men and 8 women) on four occasions in randomized order. Ghrelin was infused for 30 min to achieve steady-state levels and continued through a 3-h intravenous glucose tolerance test. The acute insulin response to glucose (AIRg), insulin sensitivity index (SI), disposition index (DI), and intravenous glucose tolerance (kg) were compared for each subject during the four infusions. AG infusion raised fasting glucose levels but had no effect on fasting plasma insulin. Compared with the saline control, AG and AG+UAG both decreased AIRg, but UAG alone had no effect. SI did not differ among the treatments. AG, but not UAG, reduced DI and kg and increased plasma growth hormone. UAG did not alter growth hormone, cortisol, glucagon, or free fatty acid levels. UAG selectively decreased glucose and fructose consumption compared with the other treatments. In contrast to previous reports, acute administration of UAG does not have independent effects on glucose tolerance or β-cell function and neither augments nor antagonizes the effects of AG.

Effects of oat bran and nutrition counseling on the lipid and glucose profile and anthropometric parameters of hypercholesterolemia patients

Background: In order to prevent chronic, non communicable disease, it is essential that lifestyle is modified to include a diet high in fiber. Aim: To assess the effect oat bran (OB) in conjunction with nutrition counseling (NC) have on lipid and glucose profile, anthropometric parameters, quality of diet, and ingestion of ultraprocessed foods (UPF) and additives in hypercholesterolemia sufferers. Method: This was a 90-day, double-blind, placebo-controlled, block-randomized trial undertaken on 132 men and women with LDL-c ≥ 130 mg/dL. The participants were sorted into two groups: OB Group (OBG) and Placebo Group (PLG), and were given NC and 40g of either OB or rice flour, respectively. Lipid and glucose profile were assessed, as were the anthropometric data, quality of diet (Diet Quality Index revised for the Brazilian population - DQI-R) and whether or not UPF or additives were consumed. Results: Both groups showed a significant decrease in anthropometric parameters and blood pressure, as well as a significant reduction in total and LDL cholesterol. There was also an improvement in DQI-R in both groups and a decrease in consumption of UPF. Blood sugar, HOMA-IR and QUICKI values were found to be significantly lower only in the OBG. Conclusion: Our findings in lipid profile and anthropometric parameters signify that NC has a beneficial effect, which is attributable to the improved quality of diet and reduced consumption of UPF. Daily consumption of 40 g of OB was found to be of additional benefit, in decreasing insulin-resistance parameters.

A influência da Ansiedade nas Competências dos Alunos da Academia Militar: Estudo de caso dos Exercício Finais - Leão 15

O presente estudo subordinado ao tema “A influência da Ansiedade nas Competências dos Alunos da Academia Militar: Estudo de caso dos Exercício Finais - Leão 15”, tem como principal finalidade identificar e quantificar a influência da ansiedade nas competências de liderança dos Cadetes-Alunos da Academia Militar. Contribuindo assim, para o reconhecimento das competências influenciadas pela ansiedade e a sua perceção no desempenho, mais propriamente na Informação Comportamental do Aluno. No estudo foi implementado um inquérito constituído por algumas questões de caráter sociodemográfico, um questionário de competências de liderança e um questionário de medição de ansiedade – STAI. Foi aplicado a um grupo de 165 Cadetes-Alunos da Academia, sendo 95 do 4º Ano Escolar e 80 do 1º Ano Escolar. De salientar que este inquérito foi realizado duas vezes: antes e depois do Exercício Leão 15. Com base nas respostas dadas, criou-se uma base de dados em Microsoft Excel, à qual se acrescentaram as notas de Informação Comportamental dos Aluno, e procedeu-se ao seu tratamento e análise estatística, com recurso ao Statistical Package for Social Sciences. (SPSS) Dos resultados obtidos identificaram-se várias diferenças significativas entre os níveis de ansiedade e as competências de liderança, relativamente ao género, ano escolar, curso, ao desporto mais praticado e ao período em análise do Exercício Leão 15 das quais se realçam: o género feminino revelou maior índice de ansiedade no período anterior ao Exercício; o 1ºAno Escolar revelou maior índice de ansiedade estado em ambos os períodos; o curso de EXE-Engenharias revelou maior ansiedade estado e ansiedade traço no período antes do Exercício e os alunos que praticam mais frequentemente desporto coletivo revelam maior Ansiedade Estado no período depois do Exercício Leão 15. Assinalaram-se ainda correlações significativas entre a ansiedade, as competências de liderança e a nota da Informação Comportamental dos Aluno com valores mais elevados nas seguintes: “trabalho de equipa e coesão”; “flexibilidade e adaptabilidade”; “autocontrolo” e “influência e referência”. Com o objetivo de procurar identificar e quantificar as competências mais influenciadas pela ansiedade, concluiu-se que as médias de ansiedade como variável preditora é maior nas competências: “flexibilidade e adaptabilidade”, “capacidade de resolver problemas”, “reconhecimento, feedback positivo e valorização”, “aptidão técnico profissional”, “gestão de conflitos e negociação”, “transparência”, “comunicação assertiva”, “comunicação” e “relações interpessoais”.

Links between body mass index, total body fat, cholesterol, high-density lipoprotein, and insulin sensitivity in patients with obesity related to depression, anger, and anxiety

OBJECTIVE: Define links between psychosocial parameters and metabolic variables in obese females before and after a low-calorie diet. METHOD: Nine female obese patients (age 36.1 +/- 7.1 years, body mass index [BMI] > 30 kg/m2) were investigated before and after a 6-week low-calorie diet accompanied by behavior therapy. Blood lipids, insulin sensitivity (Bergman protocol), fat distribution (by dual-energy X-ray absorptiometry [DEXA]), as well as psychological parameters such as depression, anger, anxiety, symptom load, and well-being, were assessed before and after the dieting period. RESULTS: The females lost 9.6 +/- 2.8 kg (p < .0001) of body weight, their BMI was reduced by 3.5 +/- 0.3 kg/m2 (p < .0001), and insulin sensitivity increased from 3.0 +/- 1.8 to 4.3 +/- 1.5 mg/kg (p = .05). Their abdominal fat content decreased from 22.3 +/- 5.5 to 18.9 +/- 4.5 kg (p < .0001). In parallel, psychological parameters such as irritability (p < .05) and cognitive control (p < .0001) increased, whereas feelings of hunger (p < .05), externality (p < .05), interpersonal sensitivity (p < .01), paranoid ideation (p < .05), psychoticism (p < .01), and global severity index (p < .01) decreased. Prospectively, differences in body fat (percent) were correlated to nervousness (p < .05). Waist-to-hip ratio (WHR) differences were significantly correlated to sociability (p < .05) and inversely to emotional instability (p < .05), whereas emotional instability was inversely correlated to differences in insulin sensitivity (p < .01). DISCUSSION: Weight reduction may lead to better somatic risk factor control. Women with more nervousness and better sociability at the beginning of a diet period may lose more weight than others.

Revised QUICKI provides a strong surrogate estimate of insulin sensitivity when compared with the minimal model

OBJECTIVE: To compare insulin sensitivity (Si) from a frequently sampled intravenous glucose tolerance test (FSIGT) and subsequent minimal model analyses with surrogate measures of insulin sensitivity and resistance and to compare features of the metabolic syndrome between Caucasians and Indian Asians living in the UK. SUBJECTS: In all, 27 healthy male volunteers (14 UK Caucasians and 13 UK Indian Asians), with a mean age of 51.2 +/- 1.5 y, BMI of 25.8 +/- 0.6 kg/m(2) and Si of 2.85 +/- 0.37. MEASUREMENTS: Si was determined from an FSIGT with subsequent minimal model analysis. The concentrations of insulin, glucose and nonesterified fatty acids (NEFA) were analysed in fasting plasma and used to calculate surrogate measure of insulin sensitivity (quantitative insulin sensitivity check index (QUICKI), revised QUICKI) and resistance (homeostasis for insulin resistance (HOMA IR), fasting insulin resistance index (FIRI), Bennetts index, fasting insulin, insulin-to-glucose ratio). Plasma concentrations of triacylglycerol (TAG), total cholesterol, high density cholesterol, (HDL-C) and low density cholesterol, (LDL-C) were also measured in the fasted state. Anthropometric measurements were conducted to determine body-fat distribution. RESULTS: Correlation analysis identified the strongest relationship between Si and the revised QUICKI (r = 0.67; P = 0.000). Significant associations were also observed between Si and QUICKI (r = 0.51; P = 0.007), HOMA IR (r = -0.50; P = 0.009), FIRI and fasting insulin. The Indian Asian group had lower HDL-C (P = 0.001), a higher waist-hip ratio (P = 0.01) and were significantly less insulin sensitive (Si) than the Caucasian group (P = 0.02). CONCLUSION: The revised QUICKI demonstrated a statistically strong relationship with the minimal model. However, it was unable to differentiate between insulin-sensitive and -resistant groups in this study. Future larger studies in population groups with varying degrees of insulin sensitivity are recommended to investigate the general applicability of the revised QUICKI surrogate technique.