Doppler cooling of gallium atoms: 2. Simulation in complex multilevel systems

This paper derives a general procedure for the numerical solution of the Lindblad equations that govern the coherences arising from multicoloured light interacting with a multilevel system. A systematic approach to finding the conservative and dissipative terms is derived and applied to the laser cooling of gallium. An improved numerical method is developed to solve the time-dependent master equation and results are presented for transient cooling processes. The method is significantly more robust, efficient and accurate than the standard method and can be applied to a broad range of atomic and molecular systems. Radiation pressure forces and the formation of dynamic dark-states are studied in the gallium isotope 66Ga.Comment: 15 pages, 8 figure

Mending the Levee: How Supernaturally Anchored Conceptions of the Person Impact on Trauma Perception and Healing among Children (Cases from Madagascar and Nepal)

When dealing with children and youth who experience distressing events, psychosocial diagnostics and healing programmes principally resort to biomedical models. Children are often viewed as individualised ‘victims’ suffering from trauma and ‘in need’ of outside help. Highlighting case studies from Madagascar and Nepal, this article argues that the biomedical approach to trauma would be strengthened by a concomitant analysis of social networks, including the perceived relations with the supernatural. The various tandems of family and kin relationships, the living and the dead, constitute not only a social ‘levee’ breached by distressing events, but also the locus around which social relations are rebuilt

Singularities of nn-fold integrals of the Ising class and the theory of elliptic curves

We introduce some multiple integrals that are expected to have the same singularities as the singularities of the $n$-particle contributions $\chi^{(n)}$ to the susceptibility of the square lattice Ising model. We find the Fuchsian linear differential equation satisfied by these multiple integrals for $n=1, 2, 3, 4$ and only modulo some primes for $n=5$ and $6$, thus providing a large set of (possible) new singularities of the $\chi^{(n)}$. We discuss the singularity structure for these multiple integrals by solving the Landau conditions. We find that the singularities of the associated ODEs identify (up to $n= 6$) with the leading pinch Landau singularities. The second remarkable obtained feature is that the singularities of the ODEs associated with the multiple integrals reduce to the singularities of the ODEs associated with a {\em finite number of one dimensional integrals}. Among the singularities found, we underline the fact that the quadratic polynomial condition $1+3 w +4 w^2 = 0$, that occurs in the linear differential equation of $\chi^{(3)}$, actually corresponds to a remarkable property of selected elliptic curves, namely the occurrence of complex multiplication. The interpretation of complex multiplication for elliptic curves as complex fixed points of the selected generators of the renormalization group, namely isogenies of elliptic curves, is sketched. Most of the other singularities occurring in our multiple integrals are not related to complex multiplication situations, suggesting an interpretation in terms of (motivic) mathematical structures beyond the theory of elliptic curves.Comment: 39 pages, 7 figure

Engineering a blue light inducible SpyCatcher system (BLISS) as a tool for protein photopatterning and optogenetics

The SpyTag-SpyCatcher protein conjugation system has recently exploded in popularity due to its fast kinetics and high yield under biologically favorable conditions in both in vitro and intracellular settings. We imagine we can further expand the utility of this system by introducing the ability to spatially and temporally control the conjugation event. Taking inspiration from photoreceptor proteins in nature, we designed a method to integrate light dependency into the protein conjugation reaction. The light-oxygen-voltage 2 domain of Avena sativa (AsLOV2) undergoes a dramatic conformational change in response to blue light. We have thus genetically fused the SpyTag into the AsLOV2 domain to create a Blue Light Inducible SpyCatcher System (BLISS). In this design (Figure 1), the SpyTag is blocked from reacting with the SpyCatcher in the dark, but upon irradiation with blue light, the Jα-helix of the AsLOV2 undocks to expose the SpyTag. We screened several likely insertion points in the Jα-helix, and found a variant with desirable light switching behavior where after one hour of irradiation, the reaction is 80% complete, while only 10% of the AsLOV2-SpyTag protein reacted in the dark. This reaction can be quenched within minutes by returning the reaction to the dark. We demonstrated the spatial aspect of this light control mechanism through photopatterning proteins onto Ni-NTA coated slides. As our system is made solely from protein components, which can be genetically encoded, we can extend the same spatiotemporal control of proteins inside cells. We anticipate BLISS will be a strong tool for fabricating protein microassays, crafting biomaterial composition, as well as optically controlling enzyme activity and protein localization in cells. Please click Additional Files below to see the full abstract

El autor piensa en público : David Lodge presenta su novela Pensamientos Ocultos'

Obra ressenyada: David LODGE, Pensamiento ocultosapplication/pd

Mepolizumab versus placebo for asthma

Background Mepolizumab is a human monoclonal antibody against interleukin-5 (IL-5), the main cytokine involved in the activation of eosinophils, which in turn causes airway inflammation. Recent studies have suggested these agents may have a role in reducing exacerbations and improving health-related quality of life (HRQoL). There are no recommendations for the use of mepolizumab in adults or children in the recent update of the BTS/SIGN guidelines (BTS/SIGN 2014). Objectives To compare the effects of mepolizumab with placebo on exacerbations and HRQoL in adults and children with chronic asthma. Search methods We searched the Cochrane Airways Group Register (CAGR) of trials, clinical trial registries, manufacturers' websites and the reference lists of included studies. Searches were conducted in November 2013 and updated in November 2014. Selection criteria We included randomised controlled trials comparing mepolizumab versus placebo in adults and children with asthma. Data collection and analysis Two authors independently extracted data and analysed outcomes using a random-effects model. We used standard methods expected by The Cochrane Collaboration. Main results Eight studies on 1707 participants met the inclusion criteria. Only two studies included children (over 12 years of age), but they did not report separate findings for the adolescents. Seven studies involved intravenous mepolizumab alone; one included a subcutaneous arm. There was heterogeneity in the severity and clinical pattern of asthma among the participants in the eight studies, varying from mild to moderate atopic asthma, to persistent asthma and eosinophilic asthma with recurrent exacerbations. Selection bias was a concern in several of the studies included in this review. Four trials compared intravenous mepolizumab to placebo in relation to HRQoL. Two studies measured scores from the Asthma Quality of Life Questionnaire (AQLQ), which showed a non-significant difference between mepolizumab and placebo (mean difference (MD) 0.21, 95% confidence interval (CI) − 0.01 to 0.44; participants = 682), in the direction favouring mepolizumab. The third study used the St. George's Respiratory Questionnaire (SGRQ) and found a significant difference between mepolizumab and placebo (MD 6.40, 95% CI 3.15 to 9.65; participants = 576), which indicated a clinically important benefit favouring mepolizumab. A fourth study noted that there was no significant difference but did not provide any data. The two studies in people with eosinophilic asthma showed a reduction in clinically significant exacerbation rates (Risk Ratio 0.52, 95% CI 0.43 to 0.64; participants = 690). However, an analysis of four studies that were not confined to people with eosinophilic asthma indicated considerable heterogeneity and no significant difference in people with one or more exacerbations between mepolizumab and placebo using a random-effects model (Risk Ratio 0.67, 95% CI 0.34 to 1.31; participants = 468; I2 = 59%).The analysis of serious adverse events indicated a significant difference favouring mepolizumab (Risk ratio 0.49, 95% CI 0.30 to 0.80; participants = 1441; studies = 5; I2 = 0%). It was not possible to combine the results for adverse events, and we deemed the quality of this evidence to be low. A single study compared subcutaneous mepolizumab to placebo in 385 adults with severe eosinophilic asthma and found an improvement in HRQoL scores and a reduction in asthma exacerbations, including exacerbations requiring admission to hospital. Authors' conclusions It is not possible to draw firm conclusions from this review with respect to the role of mepolizumab in patients with asthma. Our confidence in the results of this review are limited by the fact that the intravenous route is not currently licensed for mepolizumab, and the evidence for the currently licenced subcutaneous route is limited to a single study in participants with severe eosinophilic asthma. The currently available studies provide evidence that mepolizumab can lead to an improvement in health-related quality of life scores and reduce asthma exacerbations in people with severe eosinophilic asthma. Further research is needed to clarify which subgroups of patients with asthma could potentially benefit from this treatment. Dosage, ideal dosing regimens and duration of treatment need to be clarified, as the studies included in this review differed in their protocols. There are no studies reporting results from children, so we cannot comment on treatment for this age group. At the present time, larger studies using licenced treatment regimens are required to establish the role of mepolizumab in the treatment of severe asthma

Psychometric properties of the Children’s Revised Impact of Events Scale (CRIES) with Bangladeshi children and adolescents

Identification of possible cases suffering post-traumatic stress disorder (PTSD) is important, especially in developing countries where traumatic events are typically prevalent. The Children’s Revised Impact of Events Scale is a reliable and valid measure that has two brief versions (13 items and 8 items) to assess reactions to traumatic events among young people. The current study evaluated the psychometric properties of both versions of the CRIES in a sample of 1,342 children and adolescents aged 9–17 years (M = 12.3 years, SD = 2.12) recruited from six districts of Bangladesh. A sub-group of 120 children from four schools was re-tested on the measures within 3.5 weeks. Confirmatory factor analysis supported factor structures similar to those found in other studies for both versions of the CRIES. Multiple group confirmatory factor analysis showed gender and age-group differences within the sample, supporting established age and gender differences in prevalence of PTSD symptoms. Analyses also indicated moderate to excellent internal consistency and test-retest reliability and clear discriminant and convergent validity. These data support use of both the CRIES-13 and CRIES-8 to provide quick and psychometrically sound assessment of symptoms of PTSD among children and adolescents from Bangla-speaking communities