A 65 k.y. time series from sediment-hosted glasses reveals rapid transitions in ocean ridge magmas

Studies of ocean ridge magmatism have been hampered by the difficulty in constructing time-series data over more than a few thousand years. Sediment rapidly covers newly formed ocean crust, and older rocks, even when recovered from fault scarps, cannot be dated accurately. Ridge eruptions, however, disperse pyroclastic glass over distances as far as 5 km, and these glasses have been shown to persist for thousands of years in on-ridge sediment push cores. Here we present data on such glasses from a piston core that impacted basement in much older (600 ka) sediment. The age of deposition was determined using established stratigraphic methods to date the host sediment, yielding an average sample resolution of a few thousand years and a continuous 65 k.y. time series. The new time-series data show systematic temporal variations in magma compositions related to a change to the dynamics of crustal storage, which led to greater extents of pre-eruptive differentiation. Shortly thereafter was a small but discernable shift toward more enriched primary melt compositions. These events coincide with the onset of enhanced crustal production, previously identified using seismic data and interpreted to reflect the capture of a hotspot by the ridge. These results show the long-term preservation of pyroclastic glasses and suggest that the construction of high-resolution volcanic stratigraphy over a million years or more may be possible at ocean ridges, using multiple piston cores that impact basement. Sediment-hosted glasses have the potential to transform ocean ridges from the volcanic setting with the worst time-series data to that with the best

The standard error of measurement is a more appropriate measure of quality for postgraduate medical assessments than is reliability: an analysis of MRCP(UK) examinations

Background: Cronbach's alpha is widely used as the preferred index of reliability for medical postgraduate examinations. A value of 0.8-0.9 is seen by providers and regulators alike as an adequate demonstration of acceptable reliability for any assessment. Of the other statistical parameters, Standard Error of Measurement (SEM) is mainly seen as useful only in determining the accuracy of a pass mark. However the alpha coefficient depends both on SEM and on the ability range (standard deviation, SD) of candidates taking an exam. This study investigated the extent to which the necessarily narrower ability range in candidates taking the second of the three part MRCP(UK) diploma examinations, biases assessment of reliability and SEM.Methods: a) The interrelationships of standard deviation (SD), SEM and reliability were investigated in a Monte Carlo simulation of 10,000 candidates taking a postgraduate examination. b) Reliability and SEM were studied in the MRCP(UK) Part 1 and Part 2 Written Examinations from 2002 to 2008. c) Reliability and SEM were studied in eight Specialty Certificate Examinations introduced in 2008-9.Results: The Monte Carlo simulation showed, as expected, that restricting the range of an assessment only to those who had already passed it, dramatically reduced the reliability but did not affect the SEM of a simulated assessment. The analysis of the MRCP(UK) Part 1 and Part 2 written examinations showed that the MRCP(UK) Part 2 written examination had a lower reliability than the Part 1 examination, but, despite that lower reliability, the Part 2 examination also had a smaller SEM (indicating a more accurate assessment). The Specialty Certificate Examinations had small Ns, and as a result, wide variability in their reliabilities, but SEMs were comparable with MRCP(UK) Part 2.Conclusions: An emphasis upon assessing the quality of assessments primarily in terms of reliability alone can produce a paradoxical and distorted picture, particularly in the situation where a narrower range of candidate ability is an inevitable consequence of being able to take a second part examination only after passing the first part examination. Reliability also shows problems when numbers of candidates in examinations are low and sampling error affects the range of candidate ability. SEM is not subject to such problems; it is therefore a better measure of the quality of an assessment and is recommended for routine use

Mapping medical careers: Questionnaire assessment of career preferences in medical school applicants and final-year students

BACKGROUND: The medical specialities chosen by doctors for their careers play an important part in the workforce planning of health-care services. However, there is little theoretical understanding of how different medical specialities are perceived or how choices are made, despite there being much work in general on this topic in occupational psychology, which is influenced by Holland's RIASEC (Realistic-Investigative-Artistic-Social-Enterprising-Conventional) typology of careers, and Gottfredson's model of circumscription and compromise. In this study, we use three large-scale cohorts of medical students to produce maps of medical careers. METHODS: Information on between 24 and 28 specialities was collected in three UK cohorts of medical students (1981, 1986 and 1991 entry), in applicants (1981 and 1986 cohorts, N = 1135 and 2032) or entrants (1991 cohort, N = 2973) and in final-year students (N = 330, 376, and 1437). Mapping used Individual Differences Scaling (INDSCAL) on sub-groups broken down by age and sex. The method was validated in a population sample using a full range of careers, and demonstrating that the RIASEC structure could be extracted. RESULTS: Medical specialities in each cohort, at application and in the final-year, were well represented by a two-dimensional space. The representations showed a close similarity to Holland's RIASEC typology, with the main orthogonal dimensions appearing similar to Prediger's derived orthogonal dimensions of 'Things-People' and 'Data-Ideas'. CONCLUSIONS: There are close parallels between Holland's general typology of careers, and the structure we have found in medical careers. Medical specialities typical of Holland's six RIASEC categories are Surgery (Realistic), Hospital Medicine (Investigative), Psychiatry (Artistic), Public Health (Social), Administrative Medicine (Enterprising), and Laboratory Medicine (Conventional). The homology between medical careers and RIASEC may mean that the map can be used as the basis for understanding career choice, and for providing career counselling

The holistic phase model of early adult crisis

The objective of the current study was to explore the structural, temporal and experiential manifestations of crisis episodes in early adulthood, using a holistic-systemic theoretical framework. Based on an analysis of 50 interviews with individuals about a crisis episode between the ages of 25 and 35, a holistic model was developed. The model comprises four phases: (1) Locked-in, (2) Separation/Time-out, (3) Exploration and (4) Rebuilding, which in turn have characteristic features at four levels—person-in-environment, identity, motivation and affect-cognition. A crisis starts out with a commitment at work or home that has been made but is no longer desired, and this is followed by an emotionally volatile period of change as that commitment is terminated. The positive trajectory of crisis involves movement through an exploratory period towards active rebuilding of a new commitment, but ‘fast-forward’ and ‘relapse’ loops can interrupt Phases 3 and 4 and make a positive resolution of the episode less likely. The model shows conceptual links with life stage theories of emerging adulthood and early adulthood, and it extends current understandings of the transitional developmental challenges that young adults encounter

Serological evidence for human cystic echinococcosis in Slovenia

<p>Abstract</p> <p>Background</p> <p>Cystic echinococcosis (CE) is caused by the larva of tapeworm <it>Echinococcus granulosus</it>. Dogs and other canids are the primary definitive hosts for this parasite. CE may develop after accidental ingestion of tapeworm eggs, excreted with the feces of these animals. In the intestine, the larvae released from the eggs are nested in the liver, lungs or other organs of livestock as intermediate hosts and humans as aberrant hosts. The aim of this study was to examine serologically whether some of the patients in Slovenia, suspected of CE by imaging findings in the liver or lungs had been infected with the larva of <it>Echinococcus granulosus</it>.</p> <p>Methods</p> <p>Between January 1, 2002 and the end of December 2006, 1323 patients suspected of having echinococcosis were screened serologically by indirect haemagglutination assay (IHA). For confirmation and differentiation of <it>Echinococcus </it>spp. infection, the sera of IHA-positive patients were then retested by western blot (WB).</p> <p>Results</p> <p>Out of 127 IHA-positive sera, 34 sera were confirmed by WB and considered specific for CE. Of 34 sera of CE-positive patients sera, 32 corresponded to the characteristic imaging findings of a liver cysts and 2 to those of lung cysts. The mean age of CE-positive patients was 58.3 years. No significant differences were found between the CE-positive patients in regard to their sex.</p> <p>Conclusion</p> <p>In the study, it was found out that CE was mostly spread in the same area of Slovenia as in the past, but its prevalence decreased from 4.8 per 10⁵inhabitants in the period 1956–1968 to 1.7 per 10⁵inhabitants in the period 2002–2006. In spite of the decreased prevalence of CE in the last years, it is suggested that clinicians and public health authorities, especially in the eastern parts of Slovenia where the most CE patients come from, should pay greater attention to this disease in the future.</p

Will all scientists working on snails and the diseases they transmit please stand up?

Copyright © 2012 Adema et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.No abstract available

Mindfulness-based interventions for people diagnosed with a current episode of an anxiety or depressive disorder: a meta-analysis of randomised controlled trials

Objective Mindfulness-based interventions (MBIs) can reduce risk of depressive relapse for people with a history of recurrent depression who are currently well. However, the cognitive, affective and motivational features of depression and anxiety might render MBIs ineffective for people experiencing current symptoms. This paper presents a meta-analysis of randomised controlled trials (RCTs) of MBIs where participants met diagnostic criteria for a current episode of an anxiety or depressive disorder. Method Post-intervention between-group Hedges g effect sizes were calculated using a random effects model. Moderator analyses of primary diagnosis, intervention type and control condition were conducted and publication bias was assessed. Results Twelve studies met inclusion criteria (n = 578). There were significant post-intervention between-group benefits of MBIs relative to control conditions on primary symptom severity (Hedges g = −0.59, 95% CI = −0.12 to −1.06). Effects were demonstrated for depressive symptom severity (Hedges g = −0.73, 95% CI = −0.09 to −1.36), but not for anxiety symptom severity (Hedges g = −0.55, 95% CI = 0.09 to −1.18), for RCTs with an inactive control (Hedges g = −1.03, 95% CI = −0.40 to −1.66), but not where there was an active control (Hedges g = 0.03, 95% CI = 0.54 to −0.48) and effects were found for MBCT (Hedges g = −0.39, 95% CI = −0.15 to −0.63) but not for MBSR (Hedges g = −0.75, 95% CI = 0.31 to −1.81). Conclusions This is the first meta-analysis of RCTs of MBIs where all studies included only participants who were diagnosed with a current episode of a depressive or anxiety disorder. Effects of MBIs on primary symptom severity were found for people with a current depressive disorder and it is recommended that MBIs might be considered as an intervention for this population

Five-Year Longitudinal Assessment of the Downstream Impact on Schistosomiasis Transmission following Closure of the Three Gorges Dam

Schistosomiasis, caused by Schistosoma japonicum, is a significant parasitic disease and public health problem in China. How the parasite is transmitted there can be categorized into four distinct modes (modes I–IV) and it is predicted that the Three Gorges Dam, recently completed, will affect the way schistosomiasis is spread in these modes. We monitored transmission for a 5-year period (2002–2006) in eight villages, representative of the three modes (I–III) below the dam across four provinces (Hunan, Jiangxi, Hubei and Anhui) to determine whether there was any immediate impact of the dam on schistosomiasis spread. Human schistosomiasis incidence declined considerably within individual villages and each mode, and the yearly odds ratios (adjusted) for infection risk showed significant downward trends in all three modes over the follow-up period. The decreased human S. japonicum incidence recorded across transmission modes I–III was probably attributable to annual human and bovine praziquantel drug treatment. If an increase in schistosome transmission had occurred as a result of the dam, it would be of negligible size compared with this treatment-induced decline. There had thus been virtually no immediate impact of the TGD on schistosomiasis transmission downstream of the dam over the 5-year surveillance period

Verification of the Crooks fluctuation theorem and recovery of RNA folding free energies

The description of nonequilibrium processes in nano-sized objects, where the typical energies involved are a few times, is increasingly becoming central to disciplines as diverse as condensed-matter physics, materials science, and biophysics. Major recent developments towards a unified treatment of arbitrarily large fluctuations in small systems are described by fluctuation theorems that relate the probabilities of a system absorbing from or releasing to the bath a given amount of energy in a nonequilibrium process. Here we experimentally verify the Crooks Fluctuation Theorem (CFT) under weak and strong nonequilibrium conditions by using optical tweezers to measure the irreversible mechanical work during the unfolding and refolding of a small RNA hairpin and an RNA three-helix junction. We also show that the CFT provides a powerful way to obtain folding free energies in biomolecules by determining the crossing between the unfolding and refolding irreversible work distributions. The method makes it possible to obtain folding free energies in nonequilibrium processes that dissipate up to of the average total work exerted, thereby paving the way for reconstructing free energy landscapes along reaction coordinates in nonequilibrium single-molecule experiments.Comment: PDF file, 19 pages. Supplementary information available online at www.nature.co