Scaling properties of velocity and temperature spectra above the surface friction layer in a convective atmospheric boundary layer

International audienceWe report velocity and temperature spectra measured at nine levels from 1.42 meters up to 25.7 m over a smooth playa in Western Utah. Data are from highly convective conditions when the magnitude of the Obukhov length (our proxy for the depth of the surface friction layer) was less than 2 m. Our results are somewhat similar to the results reported from the Minnesota experiment of Kaimal et al. (1976), but show significant differences in detail. Our velocity spectra show no evidence of buoyant production of kinetic energy at at the scale of the thermal structures. We interpret our velocity spectra to be the result of outer eddies interacting with the ground, not "local free convection". We observe that velocity spectra represent the spectral distribution of the kinetic energy of the turbulence, so we use energy scales based on total turbulence energy in the convective boundary layer (CBL) to collapse our spectra. For the horizontal velocity spectra this scale is (zi ?o)2/3, where zi is inversion height and ?o is the dissipation rate in the bulk CBL. This scale functionally replaces the Deardorff convective velocity scale. Vertical motions are blocked by the ground, so the outer eddies most effective in creating vertical motions come from the inertial subrange of the outer turbulence. We deduce that the appropriate scale for the peak region of the vertical velocity spectra is (z ?o)2/3 where z is height above ground. Deviations from perfect spectral collapse under these scalings at large and small wavenumbers are explained in terms of the energy transport and the eddy structures of the flow. We find that the peaks of the temperature spectra collapse when wavenumbers are scaled using (z1/2 zi1/2). That is, the lengths of the thermal structures depend on both the lengths of the transporting eddies, ~9z, and the progressive aggregation of the plumes with height into the larger-scale structures of the CBL. This aggregation depends, in top-down fashion, on zi. The whole system is therefore highly organized, with even the smallest structures conforming to the overall requirements of the whole flow

Claims for sickness and disability benefits owing to mental disorders in the UK: trends from 1995 to 2014

Abstract Background There is international concern about the levels of sickness and disability benefits, with mental disorders known to account for a large proportion of claims. Aims To examine trends in sickness and disability benefits awarded for mental disorders in the UK. Method The researchers analysed UK Government data from 1995 to 2014. Results Mental disorders have become the most common cause of receiving benefits, with the number of claimants rising by 103% from 1995 to 1.1 million in 2014. Claimants with other conditions fell by 35%. In 2014, 47% of claims were attributed to a mental disorder. The number of long-term claimants (claiming over 5 years) with mental disorders increased by 87% from 2000 to 2011. Two-thirds of mental disorder claimants were classified as having a depressive or anxiety disorder. Conclusions Common mental disorders may involve greater morbidity and social costs than usually recognised. Availability of suitable employment, as well as individual support, may be necessary to reduce benefit levels

Against the stream: Antidepressants are not antidepressants - an alternative approach to drug action and implications for the use of antidepressants

Although antidepressants are regarded as effective and specific treatments, they are barely superior to placebo in randomised trials, and differences are unlikely to be clinically relevant. The conventional disease-centred understanding of drug action regards antidepressants as targeting an underlying brain process, but an alternative 'drug-centred' view suggests they are psychoactive substances that modify normal mental states and behaviour. These alterations, such as numbing of emotions, may reduce feelings of depression, and also create amplified placebo effects in randomised trials. Patients should be informed that there is no evidence that antidepressants work by correcting a chemical imbalance, that antidepressants have mind-altering effects, and that evidence suggests they produce no noticeable benefit compared with placebo. Declaration of interest The author is co-chairperson of the Critical Psychiatry Network

Dissociating the effect of disruptive colouration on localisation and identification of camouflaged targets

Disruptive camouflage features contrasting areas of pigmentation across the animals’ surface that form false edges which disguise the shape of the body and impede detection. In many taxa these false edges feature local contrast enhancement or edge enhancement, light areas have lighter edges and dark areas have darker edges. This additional quality is often overlooked in existing research. Here we ask whether disruptive camouflage can have benefits above and beyond concealing location. Using a novel paradigm, we dissociate the time courses of localisation and identification of a target in a single experiment. We measured the display times required for a stimulus to be located or identified (the critical duration). Targets featured either uniform, disruptive or edge enhanced disruptive colouration. Critical durations were longer for identifying targets with edge enhanced disruptive colouration camouflage even when presented against a contrasting background, such that all target types were located equally quickly. For the first time, we establish empirically that disruptive camouflage not only conceals location, but also disguises identity. This shows that this form of camouflage can be useful even when animals are not hidden. Our findings offer insights into how edge enhanced disruptive colouration undermines visual perception by disrupting object recognition

History, Violence and Collective Memory: Implications for Mental Health in Ecuador

National histories of violence shape experiences of suffering and professional responses. In Ecuador, mental health literature addressing this crucial issue is scarce and little debated. In contrast, local psychiatrists and psychologists within the country face contemporary challenges that are deeply rooted in a violent colonial past and the perpetuation of its fundamental ethos. This paper critically reviews relevant literature on collective memory and historical trauma, and focuses on Ecuador as a case study on how to incorporate history into modern mental health challenges. The discussion poses key questions and outlines possible ways for Ecuador to address the link between history and mental health, including insights from countries that have struggled with their violent pasts. This paper contributes to ongoing international debate on the role of cultural history in mental health with implications for social scientists and practising clinicians in former colonised nations

"Because You're Worth It": A Discourse Analysis of the Gendered Rhetoric of the ADHD Woman

Drawing on the traditions of discursive psychology and critical discourse analysis this study examined the presentation of attention deficit hyperactivity disorder (ADHD) in women in a sample of the most commonly identified online YouTube videos on this topic. The video material selected represented a combination of first-person testimonies from the “sufferer” and the sharing of “expertise” by “professionals.” Analysis involved the identification of common rhetorical devices and evaluation of the role of these devices in conveying various key meanings or themes. The categories generated by this method told a story of the construction of an “ADHD product” presented to women by other women, and unproblematically positioned within the biomedical discourse. Stimulant medication was endorsed for its ability to improve performance at work and in the domestic sphere. Women sufferers in the videos appear as “active consumers” promoting the ADHD diagnosis for its ability to enable them to fulfil the “superwoman” ideal. The medicalisation of underperformance witnessed in the videos is discussed in relation to literature on modern-day “discourses of femininity.

Quantifying methane and nitrous oxide emissions from the UK and Ireland using a national-scale monitoring network

The UK is one of several countries around the world that has enacted legislation to reduce its greenhouse gas emissions. In this study, we present top-down emissions of methane (CH4) and nitrous oxide (N2O) for the UK and Ireland over the period August 2012 to August 2014. These emissions were inferred using measurements from a network of four sites around the two countries. We used a hierarchical Bayesian inverse framework to infer fluxes as well as a set of covariance parameters that describe uncertainties in the system. We inferred average UK total emissions of 2.09 (1.65–2.67) Tg yr−1 CH4 and 0.101 (0.068–0.150) Tg yr−1 N2O and found our derived UK estimates to be generally lower than the a priori emissions, which consisted primarily of anthropogenic sources and with a smaller contribution from natural sources. We used sectoral distributions from the UK National Atmospheric Emissions Inventory (NAEI) to determine whether these discrepancies can be attributed to specific source sectors. Because of the distinct distributions of the two dominant CH4 emissions sectors in the UK, agriculture and waste, we found that the inventory may be overestimated in agricultural CH4 emissions. We found that annual mean N2O emissions were consistent with both the prior and the anthropogenic inventory but we derived a significant seasonal cycle in emissions. This seasonality is likely due to seasonality in fertilizer application and in environmental drivers such as temperature and rainfall, which are not reflected in the annual resolution inventory. Through the hierarchical Bayesian inverse framework, we quantified uncertainty covariance parameters and emphasized their importance for high-resolution emissions estimation. We inferred average model errors of approximately 20 and 0.4 ppb and correlation timescales of 1.0 (0.72–1.43) and 2.6 (1.9–20 3.9) days for CH4 and N2O, respectively. These errors are a combination of transport model errors as well as errors due to unresolved emissions processes in the inventory. We found the largest CH4 errors at the Tacolneston station in eastern England, which may be due to sporadic emissions from landfills and offshore gas in the North Sea