Optical Gain from InAs Nanocrystal Quantum Dots in a Polymer Matrix

We report on the first observation of optical gain from InAs nanocrystal quantum dots emitting at 1.55 microns based on a three-beam, time resolved pump-probe technique. The nanocrystals were embedded into a transparent polymer matrix platform suitable for the fabrication of integrated photonic devices.Comment: 8 pages, 3 figures. This second version is excactly the same as the first. It is resubmitted to correct some format errors appeared in the pdf file of the first versio

Deformations of Fuchsian Systems of Linear Differential Equations and the Schlesinger System

We consider holomorphic deformations of Fuchsian systems parameterized by the pole loci. It is well known that, in the case when the residue matrices are non-resonant, such a deformation is isomonodromic if and only if the residue matrices satisfy the Schlesinger system with respect to the parameter. Without the non-resonance condition this result fails: there exist non-Schlesinger isomonodromic deformations. In the present article we introduce the class of the so-called isoprincipal deformations of Fuchsian systems. Every isoprincipal deformation is also an isomonodromic one. In general, the class of the isomonodromic deformations is much richer than the class of the isoprincipal deformations, but in the non-resonant case these classes coincide. We prove that a deformation is isoprincipal if and only if the residue matrices satisfy the Schlesinger system. This theorem holds in the general case, without any assumptions on the spectra of the residue matrices of the deformation. An explicit example illustrating isomonodromic deformations, which are neither isoprincipal nor meromorphic with respect to the parameter, is also given

Edge and Bulk Transport in the Mixed State of a Type-II Superconductor

By comparing the voltage-current (V-I) curves obtained before and after cutting a sample of 2H-NbSe2, we separate the bulk and edge contributions to the transport current at various dissipation levels and derive their respective V- I curves and critical currents. We find that the edge contribution is thermally activated across a current dependent surface barrier. By contrast the bulk V-I curves are linear, as expected from the free flux flow model. The relative importance of bulk and edge contributions is found to depend on dissipation level and sample dimensions. We further show that the peak effect is a sharp bulk phenomenon and that it is broadened by the edge contribution

Where does the transport current flow in Bi2Sr2CaCu2O8 crystals?

A new measurement technique for investigation of vortex dynamics is introduced. The distribution of the transport current across a crystal is derived by a sensitive measurement of the self-induced magnetic field of the transport current. We are able to clearly mark where the flow of the transport current is characterized by bulk pinning, surface barrier, or a uniform current distribution. One of the novel results is that in BSCCO crystals most of the vortex liquid phase is affected by surface barriers resulting in a thermally activated apparent resistivity. As a result the standard transport measurements in BSCCO do not probe the dynamics of vortices in the bulk, but rather measure surface barrier properties.Comment: 11 pages, 4 figures, accepted for publication in Natur

The Arabidopsis protein phosphatase PP2C38 negatively regulates the central immune kinase BIK1

Plants recognize pathogen-associated molecular patterns (PAMPs) via cell surface-localized pattern recognition receptors (PRRs), leading to PRR-triggered immunity (PTI). The Arabidopsis cytoplasmic kinase BIK1 is a downstream substrate of several PRR complexes. How plant PTI is negatively regulated is not fully understood. Here, we identify the protein phosphatase PP2C38 as a negative regulator of BIK1 activity and BIK1-mediated immunity. PP2C38 dynamically associates with BIK1, as well as with the PRRs FLS2 and EFR, but not with the co-receptor BAK1. PP2C38 regulates PAMP-induced BIK1 phosphorylation and impairs the phosphorylation of the NADPH oxidase RBOHD by BIK1, leading to reduced oxidative burst and stomatal immunity. Upon PAMP perception, PP2C38 is phosphorylated on serine 77 and dissociates from the FLS2/EFR-BIK1 complexes, enabling full BIK1 activation. Together with our recent work on the control of BIK1 turnover, this study reveals another important regulatory mechanism of this central immune component

Protest communication ecologies

The flurry of protests since the turn of the decade has sustained a growth area in the social sciences. The diversity of approaches to the various facets and concerns raised by the collective action of aggrieved groups the world over impresses through multidisciplinarity and the wealth of insights it has generated. This introduction to a special issue of the international journal Information, Communication and Society is an invitation to recover conceptual instruments — such as the ecological trope — that have fallen out of fashion in media and communication studies. We account for their fall from grace and explicate the rationale for seeking to reinsert them into the empirical terrain of interlocking media, communication practices and protest which we aim to both capture with theory and adopt as a starting point for further analytical innovation

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

© The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe