From bcc to fcc: interplay between oscillating long-range and repulsive short-range forces

This paper supplements and partly extends an earlier publication, Phys. Rev. Lett. 95, 265501 (2005). In $d$-dimensional continuous space we describe the infinite volume ground state configurations (GSCs) of pair interactions \vfi and \vfi+\psi, where \vfi is the inverse Fourier transform of a nonnegative function vanishing outside the sphere of radius $K_0$, and $\psi$ is any nonnegative finite-range interaction of range $r_0\leq\gamma_d/K_0$, where $\gamma_3=\sqrt{6}\pi$. In three dimensions the decay of \vfi can be as slow as $\sim r^{-2}$, and an interaction of asymptotic form $\sim\cos(K_0r+\pi/2)/r^3$ is among the examples. At a dimension-dependent density $\rho_d$ the ground state of \vfi is a unique Bravais lattice, and for higher densities it is continuously degenerate: any union of Bravais lattices whose reciprocal lattice vectors are not shorter than $K_0$ is a GSC. Adding $\psi$ decreases the ground state degeneracy which, nonetheless, remains continuous in the open interval $(\rho_d,\rho_d')$, where $\rho_d'$ is the close-packing density of hard balls of diameter $r_0$. The ground state is unique at both ends of the interval. In three dimensions this unique GSC is the bcc lattice at $\rho_3$ and the fcc lattice at $\rho_3'=\sqrt{2}/r_0^3$.Comment: Published versio

Everything is culture, but culture is not everything Comments on Oloyede's paper on mental illness and culture

In zijn commentaar op Oloyede's paper stelt de auteur dat deze in zijn pleidooi voor culturele sensitiviteit in psychiatrie tot cultureel relativisme vervalt. In zijn betoog bepleit hij drie onderling verbonden noties over cultuur en psychiatrie: dat transculturele validiteit in psychiatrie diverse lagen heeft; dat culturele verandering ook verandering te weeg brengt in ziektebegrippen; en dat cultuur niet de enige factor is waarmee men verschillen tussen groepen verklaart. [cultuur, psychiatrie, culturele sensitiviteit, cultureel relativisme, transculturele validiteit] This paper is all about culture, though from a critical perspective. Oloyede points to the relatively small degree of cultural sensitivity in psychiatry. 'Undoubtedly', he argues, 'a culturally sensitive psychiatry is needed.' 1 One can hardly disagree. But in the course of his argument, it seems that to him cultural sensitivity amounts to cultural relativism. It gives the paper a scientific naiveté that I cannot endorse. I will elaborate on some issues Oloyede pays little attention to, while to me they seem of vital importance for a good understanding of the complex relationship between culture and mental illness. Firstly I will discuss the transcultural validity of psychiatric disease concepts in cross-cultural research. Secondly, I would like to elaborate on the vanishing boundaries between cultures and the limitations of the concept of 'culture bound syndromes'. Finally, I would like to stress that focusing exclusively on culture as an explanatory factor for differences in psychiatric morbidity among groups, could lead to scientific neglect of socio-economic and political factors that are at least as important as culture. Transcultural validity Oloyede's paper is prompted by the discomfort of a group of postgraduate students who were recruited as interviewers for a survey utilizing biomedically driven research instruments. The students felt a lack of correspondence between the employed research methodology and the population for which it was used. This is an important issue. Cross cultural research should include a critical examination of the appropriateness of MEDISCHE ANTROPOLOGIE 14 (2) 2002 283 the methodology, examining whether the research instruments provide the data we are looking after. In epidemiology this process is called 'cross cultural equivalence or validity'. In a classic article Flaherty et al. (1987) describe five aspects of cross cultural equivalence. I feel this description might help to clarify these points. Content equivalenc

Improving Access to Mental Health Care and Psychosocial Support within a Fragile Context: A Case Study from Afghanistan

As one article in a series on Global Mental Health Practice, Peter Ventevogel and colleagues provide a case study of their efforts to integrate brief, practice-oriented mental health training into the Afghanistan health care system at a time when the system was being rebuilt from scratch

Mapping the evidence on pharmacological interventions for non-affective psychosis in humanitarian non-specialised settings: a UNHCR clinical guidance.

BACKGROUND: Populations exposed to humanitarian emergencies are particularly vulnerable to mental health problems, including new onset, relapse and deterioration of psychotic disorders. Inadequate care for this group may lead to human rights abuses and even premature death. The WHO Mental Health Gap Action Programme Intervention Guide (mhGAP-IG), and its adaptation for humanitarian settings (mhGAP-HIG), provides guidance for management of mental health conditions by non-specialised healthcare professionals. However, the pharmacological treatment of people with non-affective psychosis who do not improve with mhGAP first-line antipsychotic treatments is not addressed. In order to fill this gap, UNHCR has formulated specific guidance on the second-line pharmacological treatment of non-affective psychosis in humanitarian, non-specialised settings. METHODS: Following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a group of international experts performed an extensive search and retrieval of evidence on the basis of four scoping questions. Available data were critically appraised and summarised. Clinical guidance was produced by integrating this evidence base with context-related feasibility issues, preferences, values and resource-use considerations. RESULTS: When first-line treatments recommended by mhGAP (namely haloperidol and chlorpromazine) are not effective, no other first-generation antipsychotics are likely to provide clinically meaningful improvements. Risperidone or olanzapine may represent beneficial second-line options. However, if these second-line medications do not produce clinically significant beneficial effects, there are two possibilities. First, to switch to the alternative (olanzapine to risperidone or vice versa) or, second, to consider clozapine, provided that specialist supervision and regular laboratory monitoring are available in the long term. If clinically relevant depressive, cognitive or negative symptoms occur, the use of a selective serotonin reuptake inhibitor may be considered in addition or as an alternative to standard psychological interventions. CONCLUSIONS: Adapting scientific evidence into practical guidance for non-specialised health workers in humanitarian settings was challenging due to the paucity of relevant evidence as well as the imprecision and inconsistency of results between studies. Pragmatic outcome evaluation studies from low-resource contexts are urgently needed. Nonetheless, the UNHCR clinical guidance is based on best available evidence and can help to address the compelling issue of undertreated, non-affective psychosis in humanitarian settings

Putting Evidence into Practice: The PLoS Medicine Series on Global Mental Health Practice

The PLoS Medicine editors announce the launch of a new series on Global Mental Health Practice, and issue a call for papers

Socio-cultural integration of Afghan refugees in Türkiye: the role of traumatic events, post-displacement stressors and mental health

Abstract Aims Socio-cultural integration of refugees has received scant attention in the academic literature. Türkiye hosts the largest number of refugees, including Afghans, as the second largest asylum-seeking group in Türkiye. There is a dearth of research into the mental health and integration of Afghan refugees in Türkiye. The aim of the present study was to investigate socio-cultural integration outcomes among Afghan refugees in Türkiye by considering the role of traumatic events and post-displacement stressors. The role of mental health in integration outcomes was further examined. Methods A cross-sectional, web-based survey study with 785 Afghan refugees in Türkiye was conducted between April and June 2021. Data were collected on socio-demographic characteristics, potentially traumatic events (PTEs) (Harvard Trauma Questionnaire), post-displacement stressors (Post-Migration Living Difficulties Checklist), mental health symptoms (Hopkins Symptoms Checklist-25), social integration- social bonds (contact with co-ethnic group members) and social bridges (contact with the host community)- and cultural integration (Vancouver Index of Acculturation). Structural equation modelling was conducted to test the hypothesized relationship between conflict and displacement-related stressors, mental health and socio-cultural integration. Results Findings showed that conflict-related traumatic events and post-displacement stressors significantly predicted higher mental health symptoms. Experiencing traumatic events significantly predicted higher levels of social bridges, adopting destination culture and lower level of maintaining heritage culture. Mental health problems predicted the relationship between stressors related to forced displacement and integration outcomes-social bridges and adopting destination culture. These findings highlight the role of mental health as an indispensable resource for socio-cultural integration. Further, conflict and displacement-related stressors are important determinants of socio-cultural integration among Afghan refugees in Türkiye. Conclusion Exposure to PTEs and post-displacement stressors were significant risk factors for the mental health and socio-cultural integration of Afghan refugees in Türkiye. These stressful experiences deteriorate refugees’ mental health, which hinders their integration into the host society

Pathways towards scaling up Problem Management Plus in Turkey: a theory of change workshop.

BACKGROUND: A considerable evidence base has been produced in recent years highlighting the effectiveness of brief scalable psychological interventions for people living in communities exposed to adversity. However, practical guidance on how to scale up these interventions to wider populations does not exist. In this paper we report on the use of Theory of Change (ToC) to plan the scale up of the World Health Organization's flagship low intensity psychological intervention "Problem Management Plus" (PM+) for Syrian refugees in Turkey. METHODS: We conducted a one-day ToC workshop in Istanbul. ToC is a participatory planning process used in the development, implementation and evaluation of projects. It is similar to driver diagrams or logic models in that it offers a tool to visually present the components needed to reach a desired long-term outcome or impact. The overall aim of ToC is to understand the change process of a complex intervention and to map out causal pathways through which an intervention or strategy has an effect. RESULTS: Twenty-four stakeholders (including governmental officials, mental health providers, officials from international/national non-governmental organisations, conflict and health researchers) participated in the ToC workshop. A ToC map was produced identifying three key elements of scaling up (the resource team; the innovation and the health system; and the user organisation) which are represented in three distinct causal pathways. Context-specific barriers related to the health system and the political environment were identified, and possible strategies for overcoming these challenges were suggested. CONCLUSION: ToC is a valuable methodology to develop an integrated framework for scaling up. The results highlight that the scaling up of PM+ for Syrian refugees in Turkey needs careful planning and investment from different stakeholders at the national level. Our paper provides a theoretical foundation of the scaling up of PM+, and exemplifies for the first time the use of ToC in planning the scaling up of an evidence-based psychological intervention in global mental health

Ground state at high density

Weak limits as the density tends to infinity of classical ground states of integrable pair potentials are shown to minimize the mean-field energy functional. By studying the latter we derive global properties of high-density ground state configurations in bounded domains and in infinite space. Our main result is a theorem stating that for interactions having a strictly positive Fourier transform the distribution of particles tends to be uniform as the density increases, while high-density ground states show some pattern if the Fourier transform is partially negative. The latter confirms the conclusion of earlier studies by Vlasov (1945), Kirzhnits and Nepomnyashchii (1971), and Likos et al. (2007). Other results include the proof that there is no Bravais lattice among high-density ground states of interactions whose Fourier transform has a negative part and the potential diverges or has a cusp at zero. We also show that in the ground state configurations of the penetrable sphere model particles are superposed on the sites of a close-packed lattice.Comment: Note adde

Lifespan-Extending Caloric Restriction or mTOR Inhibition Impair Adaptive Immunity of Old Mice By Distinct Mechanisms

Aging of the world population and a concomitant increase in age-related diseases and disabilities mandates the search for strategies to increase healthspan, the length of time an individual lives healthy and productively. Due to the age-related decline of the immune system, infectious diseases remain among the top 5–10 causes of mortality and morbidity in the elderly, and improving immune function during aging remains an important aspect of healthspan extension. Calorie restriction (CR) and more recently rapamycin (rapa) feeding have both been used to extend lifespan in mice. Preciously few studies have actually investigated the impact of each of these interventions upon in vivo immune defense against relevant microbial challenge in old organisms. We tested how rapa and CR each impacted the immune system in adult and old mice. We report that each intervention differentially altered T-cell development in the thymus, peripheral T-cell maintenance, T-cell function and host survival after West Nile virus infection, inducing distinct but deleterious consequences to the aging immune system. We conclude that neither rapa feeding nor CR, in the current form/administration regimen, may be optimal strategies for extending healthy immune function and, with it, lifespan