Material influence on the stress corrosion cracking of rock bolts

Rock bolt stress corrosion cracking (SCC) has been investigated using the linearly increasing stress test (LIST). One series of experiments determined the threshold stress of various bolt metallurgies (900 MPa for 1355AXRC, and 800 MPa for MAC and MA840B steels). The high values of threshold stress suggest that SCC begins in rock bolts when they are sheared by moving rock strata. SCC only occurred for environmental conditions which produce hydrogen on the sample surface, leading to hydrogen embrittlement and SCC. Different threshold potentials were determined for a range of metallurgies. Cold work was shown to increase the resistance of the steel to SCC. Rock bolt rib geometry does not have a direct impact on the SCC resistance properties of the bolt, although the process by which the ribs are produced can introduce tensile stresses into the bolt which lower its resistance to SCC. (C) 2004 Elsevier Ltd. All rights reserved.

Improving access to evidence-based mental health care: general practitioners and allied health professionals collaborate

This study evaluated whether projects conducted through the Access to Allied Health Services component of the Australian Better Outcomes in Mental Health Care initiative are improving access to evidence-based, non-pharmacological therapies for people with depression and anxiety. Synthesising data from the first 29 projects funded through the initiative, the study found that the models utilised in the projects have evolved over time. The projects have achieved a high level uptake; at a conservative estimate, 710 GPs and 160 allied health professionals (AHPs) have provided care to 3,476 consumers. The majority of these consumers have depression (77%) and/or anxiety disorders (55%); many are low income earners (57%); and a number have not previously accessed mental health care (40%). The projects have delivered 8,678 sessions of high quality care to these consumers, most commonly providing CBT-based cognitive and behavioural interventions (55% and 41%, respectively). In general, GPs, AHPs and consumers are sanguine about the projects, and have reported positive consumer outcomes. However, as with any new initiative, there are some practical and professional issues that need to be addressed. The projects are improving access to evidence-based, non-pharmacological therapies. The continuation and expansion of the initiative should be a priority.

Effects of reversible inactivation of the medial septum on rat exploratory behavior in the elevated plus-maze using a test-retest paradigm

The effect of intraseptal injections of lidocaine before a first or a second session in the elevated plus-maze, in a test-retest paradigm, was investigated. In addition to gross session analyses, a minute-by-minute analysis of the sessions was used to evaluate both anxiety and memory. Lidocaine injections before the test session produced increases in the frequency of entries, time spent and distance run in the open arms without affecting activity occurring in the closed arms. During the retest session, saline- and lidocaine-treated rats exhibited increased indices of anxiety and lidocaine-treated rats exhibited decreased closed-arm entries. The minute-by-minute analysis showed a faster decrease in anxiety-related behaviors during the test session by saline- than by lidocaine-treated rats and a significant decrease in closed-arm exploration by saline-treated rats, but not by lidocaine-treated ones. Lidocaine injection before the retest session produced increases in the frequency of entries, time spent and distance run in the open arms in the second session when compared with saline-treated rats. Minute-by-minute analysis showed an increase in the time spent in the open arms by lidocaine animals at the beginning of the retest session in comparison to saline animals and a significant decrease in closed-arm exploration by both groups. These results suggest that inactivation of the medial septum by lidocaine affects the expression of unconditioned and conditioned forms of anxiety in the elevated plus-maze and, in a lesser way, the acquisition and retention of spatial information. (C) 2010 Elsevier B.V. All rights reserved.

Antidepressant-Like Effects of Medial Prefrontal Cortex Deep Brain Stimulation in Rats

Background: Subcallosal cingulate gyrus (SCG) deep brain stimulation (DBS) is being investigated as a treatment for major depression. We report on the effects of ventromedial prefrontal cortex (vmPFC) DBS in rats, focusing on possible mechanisms involved in an antidepressant-like response in the forced swim test (FST). Methods: The outcome of vmPFC stimulation alone or combined with different types of lesions, including serotonin (5-HT) or nore-pineprhine (NE) depletion, was characterized in the FST. We also explored the effects of DBS on novelty-suppressed feeding, learned helplessness, and sucrose consumption in animals predisposed to helplessness. Results: Stimulation at parameters approximating those used in clinical practice induced a significant antidepressant-like response in the FST. Ventromedial PFC lesions or local muscimol injections did not lead to a similar outcome. However, animals treated with vmPFC ibotenic acid lesions still responded to DBS, suggesting that the modulation of fiber near the electrodes could play a role in the antidepressant-like effects of stimulation. Also important was the integrity of the serotonergic system, as the effects of DBS in the FST were completely abolished in animals bearing 5-HT, but not NE, depleting lesions. In addition, vmPFC stimulation induced a sustained increase in hippocampal 5-HT levels. Preliminary work with other models showed that DBS was also able to influence specific aspects of depressive-like states in rodents, including anxiety and anhedonia, but not helplessness. Conclusions: Our study suggests that vmPFC DES in rats maybe useful to investigate mechanisms involved in the antidepressant effects of SCG DBS.

Selective involvement of GABAergic mechanisms of the dorsal periaqueductal gray and inferior colliculus on the memory of the contextual fear as assessed by the fear potentiated startle test

The inferior colliculus (IC) together with the dorsal periaqueductal gray (dPAG), the amygdala and the medial hypothalamus make part of the brain aversion system, which has mainly been related to the organization of unconditioned fear. However, the involvement of the IC and dPAG in the conditioned fear is still unclear. It is certain that GABA has a regulatory role on the aversive states generated and elaborated in these midbrain structures. In this study, we evaluated the effects of injections of the GABA-A receptor agonist muscimol (1.0 and 2.0 nmol/0.2 mu L) into the IC or dPAG on the freezing and fear-potentiated startle (FPS) responses of rats submitted to a context fear conditioning. Intra-IC injections of muscimol did not cause any significant effect on the FPS or conditioned freezing but enhanced the startle reflex in non-conditioned animals. In contrast, intra-dPAG injections of muscimol caused significant reduction in FPS and conditioned freezing without changing the startle reflex in non-conditioned animals. Thus, intra-dPAG injections of muscimol produced the expected inhibitory effects on the anxiety-related responses, the FPS and the freezing whereas these injections into the IC produced quite opposite effects suggesting that descending inhibitory pathways from the IC, probably mediated by GABA-A mechanisms, exert a regulatory role on the lower brainstem circuits responsible for the startle reflex. (C) 2008 Elsevier Inc. All rights reserved.

Offspring size effects in the marine environment: A field test for a colonial invertebrate

A central tenet of life-history theory is the presence of a trade-off between the size and number of offspring that a female can produce for a given clutch. A crucial assumption of this trade-off is that larger offspring perform better than smaller offspring. Despite the importance of this assumption empirical, field-based tests are rare, especially for marine organisms. We tested this assumption for the marine invertebrate, Diplosoma listerianum, a colonial ascidian that commonly occurs in temperate marine communities. Colonies that came from larger larvae had larger feeding structures than colonies that came from smaller larvae. Colonies that came from larger larvae also had higher survival and growth after 2 weeks in the field than colonies that came from smaller larvae. However, after 3 weeks in the field the colonies began to fragment and we could not detect an effect of larval size. We suggest that offspring size can have strong effects on the initial recruitment of D. listerianum but because of the tendency of this species to fragment, offspring size effects are less persistent in this species than in others.

Mental health and socio-economic variations in Australian suicide

This paper investigates the relationship between suicide rates and prevalence of mental disorder and suicide attempts, across socio-economic status (SES) groups based on area of residence. Australian suicide data (1996-1998) were analysed in conjunction with area-based prevalences of mental disorder derived from the National Survey of Mental Health and Well-Being (1997). Poisson regression models of suicide risk included age, quintile of area-based SES, urban-rural residence, and country of birth (COB), with males and females analysed separately. Analysis focussed on the association between suicide and prevalences of (ICD-10) affective disorders, anxiety disorders, substance use disorders and suicide attempts by SES group. Prevalences of other psychiatric symptomatology, substance use problems, health service utilisation, stressful life-events and personality were also investigated. Significant increasing gradients were evident from high to low SES groups for prevalences of affective disorders, anxiety disorders (females only), and substance use disorders (males only); sub-threshold drug and alcohol problems and depression; and suicide attempts and suicide (males only). Prevalences of mental disorder, other sub-threshold mental health items and suicide attempts were significantly associated with suicide, but in most cases associations were reduced in magnitude and became statistically non-significant after adjustment for COB, urban-rural residence, and SES. For male suicide the relative risk (RR) in the lowest SES group compared to the highest was 1.40 (95% CI 1.29-1.52, p < 0.001) for all ages, and 1.46 (95% CI 1.27-1.67, p < 0.001) for male youth (20-34 years). This relationship was not substantially modified in males when regression models included prevalences of affective disorders, and other selected mental health variables and demographic factors. From a population perspective, SES remained significantly associated with suicide after controlling for the prevalence of mental disorders and other psychiatric symptomatology. Mental conditions and previous suicidal behaviour may play an intermediary role between SES and suicide, but this study suggests that an independent relationship between suicide and SES also exists. (c) 2005 Elsevier Ltd. All rights reserved.

Assessment of vocational guidance: The Berufsbilder test

The object of this study is to assess informative possibilities of some technical indicators of the Test of Photos of Professions (BBT - Berufsbilder test), a projective method to clarify professional inclination, proposed by Martin Achtnich. This psychological evaluation technique is composed of 96 photos of professionals, performing various types of activities. The test subject classifies the photos into three groups: positive (agreeable), negative (disagreeable) and indifferent (neutral). Among those chosen positively, five preferences are chosen and a story is developed that includes them, an activity that is requested two times during the Vocational Guidance process: in the beginning (or middle) and at the end of the intervention. In this study, 160 stories were created by 80 youths, between 15 and 20 years of age, in public and private schools in a mid-sized Brazilian city. The stories were compared in three analytical categories: protagonist, professional conflict and resolution. The results were submitted to Wilcoxon nonparametric statistical analysis (p < .05), significant and relevant indicators of resolution being found in the process of occupational choice. This technical resource was shown, from this empirical evidence, to be promising for use in evaluation of intervention processes of Vocational Guidance.

Prevalence of Alcohol-Related Problems in an Elderly Population and Their Association With Cognitive Impairment and Dementia

Background: Studies investigating the association between alcohol use and cognitive disorders in the elderly population have produced divergent results. Moreover, the role of alcohol in cognitive dysfunction is not clear. The aims of this study were to estimate the prevalence of alcohol-related problems in an elderly population from Brazil and to investigate their association with cognitive and functional impairment (CFI) and dementia. Methods: A community-based cross-sectional study was performed. A sample of 1,145 elderly people was examined in 2 phases. Several instruments were utilized in the first phase: the CAGE questionnaire was used to identify potential cases of alcohol-related problems, and a screening test for dementia was used to estimate CFI. The CAMDEX interview (Cambridge Examination) and DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) criteria were used for the clinical diagnosis of dementia in the second phase. Results: ""Heavy alcohol use"" (CAGE >= 2) was found in 92 subjects (prevalence: 8.2%). It was associated with gender (males, p < 0.001), low education (only in females, p = 0.002), and low socioeconomic level (p = 0.001, in females; p = 0.002, in males). The Mini Mental State Examination exhibited a nonlinear relationship with alcohol-related problems in females; ""mild-moderate alcohol use"" (CAGE < 2) presented the highest score. A significant association between alcohol-related problems and cognitive dysfunction was found only in females. ""Heavy alcohol use"" was associated with higher CFI and dementia rates compared to ""mild-moderate alcohol use"" (p = 0.003 and p < 0.001, respectively). ""Mild-moderate alcohol use"" had a tendency of association with lower CFI and dementia rates when compared to ""no alcohol use"" (p = 0.063 and 0.050, respectively). Conclusion: Our findings suggest that alcohol use does not have a linear relationship with cognitive decline.

Improving Alzheimer`s Disease Diagnosis with Machine Learning Techniques

There is not a specific test to diagnose Alzheimer`s disease (AD). Its diagnosis should be based upon clinical history, neuropsychological and laboratory tests, neuroimaging and electroencephalography (EEG). Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to follow treatment results. In this study we used a Machine Learning (ML) technique, named Support Vector Machine (SVM), to search patterns in EEG epochs to differentiate AD patients from controls. As a result, we developed a quantitative EEG (qEEG) processing method for automatic differentiation of patients with AD from normal individuals, as a complement to the diagnosis of probable dementia. We studied EEGs from 19 normal subjects (14 females/5 males, mean age 71.6 years) and 16 probable mild to moderate symptoms AD patients (14 females/2 males, mean age 73.4 years. The results obtained from analysis of EEG epochs were accuracy 79.9% and sensitivity 83.2%. The analysis considering the diagnosis of each individual patient reached 87.0% accuracy and 91.7% sensitivity.

Comparison of Quantitative T-Wave Alternans Profiles of Healthy Subjects and ICD Patients

Background: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. Methods: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values <= 0.05. Discriminatory performance was evaluated by a binary logistic regression model. Results: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 +/- 2 mu V; 8 +/- 9 mu V; p < 0.001) and peak TWA values (26 +/- 13 mu V; 37 +/- 20 mu V; p = 0,009) as well as on baseline TWA heart rate (79 +/- 10 bpm; 67 +/- 15 bpm; p < 0.001) and peak TWA heart rate (118 +/- 8 bpm; 90 +/- 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. Conclusions: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols. Ann Noninvasive Electrocardiol 2009;14(2):108-118.

Portuguese version of the Delirium Rating Scale-Revised-98: reliability and validity

Objective To assess the validity and the reliability of the Portuguese version of the Delirium Rating Scale-Revised-98 (DRS-R-98). Methods The scale was translated into Portuguese and back-translated into English. After assessing its face validity, five diagnostic groups (n = 64; delirium, depression, dementia, schizophrenia and others) were evaluated by two independent researchers blinded to the diagnosis. Diagnosis and severity of delirium as measured by the DRS-R-98 were compared to clinical diagnosis, Mini-Mental State Exam, Confusion Assessment Method, and Clinical Global Impressions scale (CGI). Results Mean and rnedian DRS-R-98 total scores significantly distinguished delirium from the other groups (p < 0.001). Inter-rater reliability (ICC between 0.9 and 1) and internal consistency (alpha = 0.91) were very high. DRS-R-98 severity scores correlated highly with the CGI. Mean DRS-R-98 severity scores during delirium differed significantly (p < 0.01) from the post-treatment values. The area under the curve established by ROC analysis was 0.99 and using the cut-off Value of 20 the scale showed sensitivity and specificity of 92.6% and 94.6%, respectively. Conclusion The Portuguese version of the DRS-R-98 is a valid and reliable measure of delirium that distinguishes delirium from other disorders and is sensitive to change in delirium severity, which may be of great value for longitudinal studies. Copyright (c) 2007 John Wiley & Sons, Ltd.