Non-strategic ignorance: Considering the potential for a paradigm shift in evidence-based mental health

Randomised controlled trials form a central building block within the prevailing evidence-based mental health paradigm. Both methodology and paradigm have been widely problematised since their emergence in the mid-late twentieth century. We draw on the concept of ‘strategic ignorance’ to understand why the paradigm still prevails. We present focus group data gathered from 37 participants (service users, public, carers, general practitioners, commissioners) concerning the way they made sense of a randomised controlled trial of psychotherapy for treatment-resistant depression. Thematic analysis of the findings revealed an overall critique of randomised controlled trial methods which we refer to as ‘non-strategic ignorance’. Specifically, participants problematised the construct of depression, unseating the premise of the randomised controlled trial; they were sceptical about the purpose and highlighted its failure to show how therapy works or who might benefit; the randomised controlled trial was seen as inadequate for informing decisions about how to select a therapy. Participants assumed the treatment would be cost-effective given the client group and nature of the therapy, irrespective of any randomised controlled trial findings. Each area of lay (‘non-strategic’) critique has an analogous form within the methodological expert domain. We argue that ‘expert’ critiques have generally failed to have paradigmatic impact because they represent strategic ignorance. Yet parallel non-strategic critiques have common sense appeal, highlighting the potential power of lay voices. The discussion considers whether the evidence-based mental health paradigm is faced with epistemological problems of such complexity that the conditions exist for a new paradigm in which service user views are central and randomised controlled trials peripheral

Wideband THz time domain spectroscopy based on optical rectification and electro-optic sampling

We present an analytical model describing the full electromagnetic propagation in a THz time-domain spectroscopy (THz-TDS) system, from the THz pulses via Optical Rectification to the detection via Electro Optic-Sampling. While several investigations deal singularly with the many elements that constitute a THz-TDS, in our work we pay particular attention to the modelling of the time-frequency behaviour of all the stages which compose the experimental set-up. Therefore, our model considers the following main aspects: (i) pump beam focusing into the generation crystal; (ii) phase-matching inside both the generation and detection crystals; (iii) chromatic dispersion and absorption inside the crystals; (iv) Fabry-Perot effect; (v) diffraction outside, i.e. along the propagation, (vi) focalization and overlapping between THz and probe beams, (vii) electro-optic sampling. In order to validate our model, we report on the comparison between the simulations and the experimental data obtained from the same set-up, showing their good agreement

Patient dose reduction during voiding cystourethrography

Voiding cystourethrography (VCUG) is a commonly performed examination in a pediatric uroradiology practice. This article contains suggestions on how the radiation dose to a child from VCUG can be made ‘as low as reasonably achievable–(ALARA). The pediatric radiologist should consider the appropriateness of the clinical indication before performing VCUG and utilize radiation exposure techniques and parameters during VCUG to reduce radiation exposure to a child. The medical physicist and fluoroscope manufacturer can also work together to optimize a pulsed-fluoroscopy unit and further reduce the radiation exposure. Laboratory and clinical research is necessary to investigate methods that reduce radiation exposures during VCUG, and current research is presented here

On type Ia supernovae and the formation of single low-mass white dwarfs

There is still considerable debate over the progenitors of type Ia supernovae (SNe Ia). Likewise, it is not agreed how single white dwarfs with masses less than ~0.5 Msun can be formed in the field, even though they are known to exist. We consider whether single low-mass white dwarfs (LMWDs) could have been formed in binary systems where their companions have exploded as a SN Ia. In this model, the observed single LMWDs are the remnants of giant-branch donor stars whose envelopes have been stripped off by the supernova explosion. We investigate the likely remnants of SNe Ia, including the effects of the explosion on the envelope of the donor star. We also use evolutionary arguments to examine alternative formation channels for single LMWDs. In addition, we calculate the expected kinematics of the potential remnants of SNe Ia. SN Ia in systems with giant-branch donor stars can naturally explain the production of single LMWDs. It seems difficult for any other formation mechanism to account for the observations, especially for those single LMWDs with masses less than ~0.4 Msun. Independent of those results, we find that the kinematics of one potentially useful population containing single LMWDs is consistent with our model. Studying remnant white-dwarf kinematics seems to be a promising way to investigate SN Ia progenitors. The existence of single LMWDs appears to constitute evidence for the production of SNe Ia in binary systems with a red-giant donor star. Other single white dwarfs with higher space velocities support a second, probably dominant, population of SN Ia progenitors which contained main-sequence or subgiant donor stars at the time of explosion. The runaway stars LP400-22 and US 708 suggest the possibility of a third formation channnel for some SNe Ia in systems where the donor stars are hot subdwarfs.Comment: Accepted for publication in Astronomy & Astrophysic

Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation

Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al

Phonons and related properties of extended systems from density-functional perturbation theory

This article reviews the current status of lattice-dynamical calculations in crystals, using density-functional perturbation theory, with emphasis on the plane-wave pseudo-potential method. Several specialized topics are treated, including the implementation for metals, the calculation of the response to macroscopic electric fields and their relevance to long wave-length vibrations in polar materials, the response to strain deformations, and higher-order responses. The success of this methodology is demonstrated with a number of applications existing in the literature.Comment: 52 pages, 14 figures, submitted to Review of Modern Physic

Infant mortality trends in a region of Belarus, 1980–2000

BACKGROUND: The Chernobyl disaster in 1986 and the breakup of the former Soviet Union (FSU) in 1991 challenged the public health infrastructure in the former Soviet republic of Belarus. Because infant mortality is regarded as a sensitive measure of the overall health of a population, patterns of neonatal and postneonatal deaths were examined within the Mogilev region of Belarus between 1980 and 2000. METHODS: Employing administrative death files, this study utilized a regional cohort design that included all infant deaths occurring among persons residing within the Mogilev oblast of Belarus between 1980 and 2000. Patterns of death and death rates were examined across 3 intervals: 1980–1985 (pre-Chernobyl), 1986–1991 (post-Chernobyl & pre-FSU breakup), and 1992–2000 (post-Chernobyl & post-FSU breakup). RESULTS: Annual infant mortality rates declined during the 1980s, increased during the early 1990s, and have remained stable thereafter. While infant mortality rates in Mogilev have decreased since the period 1980–1985 among both males and females, this decrement appears due to decreases in postneonatal mortality. Rates of postneonatal mortality in Mogilev have decreased since the period 1980–1985 among both males and females. Analyses of trends for infant mortality and neonatal mortality demonstrated continuous decreases between 1990, followed by a bell-shaped excess in the 1990's. Compared to rates of infant mortality for other countries, rates in the Mogilev region are generally higher than rates for the United States, but lower than rates in Russia. During the 1990s, rates for both neonatal and postneonatal mortality in Mogilev were two times the comparable rates for East and West Germany. CONCLUSIONS: While neonatal mortality rates in Mogilev have remained stable, rates for postneonatal mortality have decreased among both males and females during the period examined. Infant mortality rates in the Mogilev region of Belarus remain elevated compared to rates for other western countries, but lower than rates in Russia. The public health infrastructure might attempt to assure that prenatal, maternal, and postnatal care is maximized

First-principles calculation of the band offset at BaO/BaTiO3_3 and SrO/SrTiO3_3 interfaces

We report first-principles density-functional pseudopotential calculations on the atomic structures, electronic properties, and band offsets of BaO/BaTiO$_3$ and SrO/SrTiO$_3$ nanosized heterojunctions grown on top of a silicon substrate. The density of states at the junction does not reveal any electronic induced interface states. A dominant perovskite character is found at the interface layer. The tunability of the band offset with the strain conditions imposed by the substrate is studied. Using previously reported theoretical data available for Si/SrO, Si/BaO and BaTiO$_{3}$/SrRuO$_{3}$ interfaces we extrapolate a value for the band alignments along the whole gate stacks of technological interest: Si/SrO/SrTiO$_3$ and Si/BaO/BaTiO$_3$/SrRuO$_3$ heterostructures.Comment: 12 pages, 6 figures, submitted to Phys. Rev.

First-principles study of the effect of charge on the stability of a diamond nanocluster surface

Effects of net charge on the stability of the diamond nanocluster are investigated using the first-principles pseudopotential method with the local density approximation. We find that the charged nanocluster favors the diamond phase over the reconstruction into a fullerene-like structure. Occupying the dangling bond orbitals in the outermost surface, the excess charge can stabilize the bare diamond surface and destabilize the C-H bond on the hydrogenated surface. In combination with recent experimental results, our calculations suggest that negative charging could promote the nucleation and further growth of low-pressure diamond.open8