Tensile Tests of NACA and Conventional Machine-countersunk Flush Rivets

An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets

Tensile Tests of Round-head, Flat-head, and Brazier-head Rivets

An investigation was conducted to determine the tensile strength of round-head (AN43C), flat-head(AN442), and brazier-head (AN4556) aluminum-alloy rivets because of the scarcity of information on the tensile strength of rivets. The results of the investigation are presented as curves that show the variation of the ratio of the tensile strength of the rivet to the tensile strength of the rivet crank with the ratio of the sheet thickness to the rivet diameter for the different types of rivet

Crossing the Antarctica: Exploring the Effects of Appetite-Regulating Hormones and Indicators of Nutrition Status during a 93-Day Solo-Expedition

Future deep space astronauts must maintain adequate nutrition despite highly stressful, isolated, confined and dangerous environments. The present case-study investigated appetite regulating hormones, nutrition status, and physical and emotional stress in a space analog condition: an explorer conducting a 93-day unsupported solo crossing of Antarctica. Using the dried blood spot (DBS) method, the subject drew samples of his blood on a regular basis during the expedition. The DBSs were later analyzed for the appetite regulating hormones leptin and adiponectin. Energy intake and nutritional status were monitored by analysis of albumin and globulin (including their ratio). Interleukin-6 (IL-6) was also analyzed and used as an energy sensor. The results showed a marked reduction in levels of the appetite-reducing hormone, leptin, and the appetite stimulating hormone, adiponectin, during both extreme physical and psychological strain. Nutrition status showed a variation over the expedition, with below-normal levels during extreme psychological strain and levels abutting the lower bounds of the normal range during a phase dominated by extreme physical hardship. The IL-6 levels varied substantially, with levels above the normal range except during the recovery phase. It was concluded that a daily intake of 5058 to 5931 calories seemed to allow recovery of both appetite and nutritional status between extreme physical and psychological hardship during a long Arctic expedition. Furthermore, IL-6 may be a sensor in the muscle-liver, muscle-fat and muscle-brain crosstalk. These results may help guide nutrition planning for future astronaut crews, mountaineers and others involved in highly demanding missions.publishedVersio

Recovery from Posttraumatic Stress Symptoms: A Qualitative Study of Attributions in Survivors of War

This study was funded by a grant from the European Commission, contract number INCO-CT-2004-50917

Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean

This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features

In ICU state anxiety is not associated with posttraumatic stress symptoms over six months after ICU discharge: A prospective study

Background: Posttraumatic stress symptoms are common after intensive care treatment. The influence of anxiety during critical illness on the development of posttraumatic stress symptoms needs to be investigated. Objective: To determine the association between anxiety during critical illness (state and trait components) and posttraumatic stress symptoms over six months after ICU discharge. Methods: Prospective study including 141 patients admitted ≥24. h to a closed mixed adult ICU in a tertiary hospital. State anxiety was assessed with the Faces Anxiety Scale during ICU stay. Trait anxiety was measured with the State-Trait Anxiety Inventory Form Y-2. Posttraumatic stress symptoms were measured at three and six months after ICU discharge using the Post-Traumatic Stress Symptoms 10-Question Inventory. Clinical and demographical data were also collected. Mixed effect regression models were used to determine if state and trait anxiety were factors significantly associated with posttraumatic stress symptoms over time. Results: Moderate to severe levels of state anxiety in ICU were reported by 81 (57%) participants. Levels of trait anxiety (median 36 IQR: 29-47) were similar to the Australian population. High levels of posttraumatic stress symptoms occurred at three (n = 19, 19%) and six months (n = 15, 17%). Factors independently associated with posttraumatic stress symptoms were trait anxiety (2.2; 95% CI, 0.3-4.1; p = 0.02), symptoms of anxiety after ICU discharge (0.6; 95% CI, 0.2-1.1; p = 0.005), younger age (-1.4; 95% CI, -2.6 to -0.2; p = 0.02) and evidence of mental health treatment prior to the ICU admission (5.2; 95% CI, 1.5-8.9; p = 0.006). Conclusions: Posttraumatic stress symptoms occurred in a significant proportion of ICU survivors and were significantly associated with higher levels of trait anxiety, younger age, mental health treatment prior to the ICU admission and more symptoms of anxiety after ICU discharge. Early assessment and interventions directed to reduce state and trait anxiety in ICU survivors may be of benefit

Shift Work Disorder in Nurses – Assessment, Prevalence and Related Health Problems

BACKGROUND: This study investigates the prevalence of symptoms of shift work disorder in a sample of nurses, and its association to individual, health and work variables. METHODOLOGY/PRINCIPAL FINDINGS: We investigated three different shift work disorder assessment procedures all based on current diagnostic criteria and employing symptom based questions. Crude and adjusted logistic regression analyses were performed with symptoms of shift work disorder as the dependent variable. Participants (n = 1968) reported age, gender, work schedule, commuting time, weekly work hours, children in household, number of nights and number of shifts separated by less than 11 hours worked the last year, use of bright light therapy, melatonin and sleep medication, and completed the Bergen Insomnia Scale, Epworth Sleepiness Scale, Global Sleep Assessment Questionnaire, Diurnal Scale, Revised Circadian Type Inventory, Dispositional Resilience (Hardiness) Scale--Revised, Fatigue Questionnaire, questions about alcohol and caffeine consumption, as well as the Hospital Anxiety and Depression Scale. CONCLUSIONS/SIGNIFICANCE: Prevalence rates of symptoms of shift work disorder varied from 32.4-37.6% depending on the assessment method and from 4.8-44.3% depending on the work schedule. Associations were found between symptoms of shift work disorder and age, gender, circadian type, night work, number of shifts separated by less than 11 hours and number of nights worked the last year, insomnia and anxiety. The different assessment procedures yielded similar results (prevalence and logistic regression analyses). The prevalence of symptoms indicative of shift work disorder was high. We argue that three symptom-based questions used in the present study adequately assess shift work disorder in epidemiological studies

Refining trait resilience: identifying engineering, ecological, and adaptive facets from extant measures of resilience

The current paper presents a new measure of trait resilience derived from three common mechanisms identified in ecological theory: Engineering, Ecological and Adaptive (EEA) resilience. Exploratory and confirmatory factor analyses of five existing resilience scales suggest that the three trait resilience facets emerge, and can be reduced to a 12-item scale. The conceptualization and value of EEA resilience within the wider trait and well-being psychology is illustrated in terms of differing relationships with adaptive expressions of the traits of the five-factor personality model and the contribution to well-being after controlling for personality and coping, or over time. The current findings suggest that EEA resilience is a useful and parsimonious model and measure of trait resilience that can readily be placed within wider trait psychology and that is found to contribute to individual well-bein