An investigation of traumatic life events and obsessive-compulsive disorder.

Abstract Obsessive-compulsive disorder (OCD), like most other psychiatric disorders, is suspected of being influenced by an interaction between life events and genes, both with regard to onset and course of illness. To date, no specific genes have been identified as playing a frequent role, and only a relatively few empirical studies have assessed the association between stressful life events (SLEs) and OCD. The present study builds on past research by examining the potential contributions from traumatic life events (TLEs) on the severity and symptom features in 265 individuals with Structured Clinical Interview for DSM-IV (SCID)-diagnosed OCD. Of these participants 54% endorsed having experienced at least one TLE in their life time. The presence of one or more TLEs was associated with increased OCD symptom severity. This relationship remained significant despite controlling for key variables including age, OCD age-of-onset, comorbidity, and depressive symptoms. In addition, obsessions/checking and symmetry/ordering were two of four symptom factors that were specifically associated with the occurrence of TLEs. These results are generally supportive of a pathoplastic relationship between TLEs and OCD symptomatology and thus suggest the need for greater systematic consideration of life stresses in research focused on the nature and treatment of OCD.

Turbulent Mixing in the Interstellar Medium -- an application for Lagrangian Tracer Particles

We use 3-dimensional numerical simulations of self-gravitating compressible turbulent gas in combination with Lagrangian tracer particles to investigate the mixing process of molecular hydrogen (H2) in interstellar clouds. Tracer particles are used to represent shock-compressed dense gas, which is associated with H2. We deposit tracer particles in regions of density contrast in excess of ten times the mean density. Following their trajectories and using probability distribution functions, we find an upper limit for the mixing timescale of H2, which is of order 0.3 Myr. This is significantly smaller than the lifetime of molecular clouds, which demonstrates the importance of the turbulent mixing of H2 as a preliminary stage to star formation.Comment: 10 pages, 5 figures, conference proceedings "Turbulent Mixing and Beyond 2007

The relationship between strategic control and conscious structural knowledge in artificial grammar learning

We address Jacoby’s (1991) proposal that strategic control over knowledge requires conscious awareness of that knowledge. In a two-grammar artificial grammar learning experiment all participants were trained on two grammars, consisting of a regularity in letter sequences, while two other dimensions (colours and fonts) varied randomly. Strategic control was measured as the ability to selectively apply the grammars during classification. For each classification, participants also made a combined judgement of (a) decision strategy and (b) relevant stimulus dimension. Strategic control was found for all types of decision strategy, including trials where participants claimed to lack conscious structural knowledge. However, strong evidence of strategic control only occurred when participants knew or guessed that the letter dimension was relevant, suggesting that strategic control might be associated with – or even causally requires – global awareness of the nature of the rules even though it does not require detailed knowledge of their content

Professional approaches in clinical judgements among senior and junior doctors: implications for medical education

<p>Abstract</p> <p>Background</p> <p>Clinical experience has traditionally been highly valued in medical education and clinical healthcare. On account of its multi-faceted nature, clinical experience is mostly difficult to articulate, and is mainly expressed in clinical situations as professional approaches. Due to retirement, hospitals in Scandinavia will soon face a substantial decrease in the number of senior specialist doctors, and it has been discussed whether healthcare will suffer an immense loss of experienced-based knowledge when this senior group leaves the organization. Both senior specialists and junior colleagues are often involved in clinical education, but the way in which these two groups vary in professional approaches and contributions to clinical education has not been so well described. Cognitive psychology has contributed to the understanding of how experience may influence professional approaches, but such studies have not included the effect of differences in position and responsibilities that junior and senior doctors hold in clinical healthcare. In the light of the discussion above, it is essential to describe the professional approaches of senior doctors in relation to those of their junior colleagues. This study therefore aims to describe and compare the professional approaches of junior and senior doctors when making clinical judgements.</p> <p>Methods</p> <p>Critical incident technique was used in interviews with nine senior doctors and nine junior doctors in internal medicine. The interviews were subjected to qualitative content analysis.</p> <p>Result</p> <p>Senior and junior doctors expressed a variety of professional approaches in clinical judgement as follows: use of theoretical knowledge, use of prior experience of cases and courses of events, use of ethical and moral values, meeting and communicating with the patient, focusing on available information, relying on their own ability, getting support and guidance from others and being directed by the organization.</p> <p>Conclusion</p> <p>The most prominent varieties of professional approaches were seen in use of knowledge and work-related experience. Senior doctors know how the organization has worked in the past and have acquired techniques with respect to long-term decisions and their consequences. Junior doctors, on the other hand, have developed techniques and expertise for making decisions based on a restricted amount of information, in relation to patients' wellbeing as well as organizational opportunities and constraints. This study contributes to medical education by elucidating the variation in professional approaches among junior and senior doctors, which can be used as a basis for discussion about clinical judgement, in both pre-clinical and clinical education. Further research is required to explain how these professional approaches are expressed and used in clinical education.</p

Script Concordance Tests: Guidelines for Construction

International audienc

Electronic Structure of the Cuprate Superconducting and Pseudogap Phases from Spectroscopic Imaging STM

We survey the use of spectroscopic imaging STM to probe the electronic structure of underdoped cuprates. Two distinct classes of electronic states are observed in both the d-wave superconducting (dSC) and the pseudogap (PG) phases. The first class consists of the dispersive Bogoliubov quasiparticle excitations of a homogeneous d-wave superconductor, existing below a lower energy scale E=Delta0. We find that the Bogoliubov quasiparticle interference signatures of delocalized Cooper pairing are restricted to a k-space arc which terminates near the lines connecting k=\pm(pi/a0,0) to k=\pm(pi/a0). This arc shrinks continuously with decreasing hole density such that Luttinger's theorem could be satisfied if it represents the front side of a hole-pocket which is bounded behind by the lines between k=\pm(pi/a0,0) and k=\pm(0,pi/a0). In both phases the only broken symmetries detected for the |E|<Delta0 states are those of a d-wave superconductor. The second class of states occurs proximate to the pseudogap energy scale E=Delta1. Here the non-dispersive electronic structure breaks the expected 90o-rotational symmetry of electronic structure within each unit cell, at least down to 180o-rotational symmetry. This Q=0 electronic symmetry breaking was first detected as an electronic inequivalence at the two oxygen sites within each unit cell by using a measure of nematic (C2) symmetry. Incommensurate non-dispersive conductance modulations, locally breaking both rotational and translational symmetries, coexist with this intra-unit-cell electronic symmetry breaking at E=Delta1. Their characteristic wavevector Q is determined by the k-space points where Bogoliubov quasiparticle interference terminates and therefore changes continuously with doping. The distinct broken electronic symmetry states (Q=0 and finite Q) coexisting at E~Delta1 are found to be indistinguishable in the dSC and PG phases.Comment: 32 pages with 10 figure

Stress-driven instability in growing multilayer films

We investigate the stress-driven morphological instability of epitaxially growing multilayer films, which are coherent and dislocation-free. We construct a direct elastic analysis, from which we determine the elastic state of the system recursively in terms of that of the old states of the buried layers. In turn, we use the result for the elastic state to derive the morphological evolution equation of surface profile to first order of perturbations, with the solution explicitly expressed by the growth conditions and material parameters of all the deposited layers. We apply these results to two kinds of multilayer structures. One is the alternating tensile/compressive multilayer structure, for which we determine the effective stability properties, including the effect of varying surface mobility in different layers, its interplay with the global misfit of the multilayer film, and the influence of asymmetric structure of compressive and tensile layers on the system stability. The nature of the asymmetry properties found in stability diagrams is in agreement with experimental observations. The other multilayer structure that we study is one composed of stacked strained/spacer layers. We also calculate the kinetic critical thickness for the onset of morphological instability and obtain its reduction and saturation as number of deposited layers increases, which is consistent with recent experimental results. Compared to the single-layer film growth, the behavior of kinetic critical thickness shows deviations for upper strained layers.Comment: 27 pages, 11 figures; Phys. Rev. B, in pres