Self modulated dynamics of a relativistic charged particle beam in plasma wake field excitation

Self modulated dynamics of a relativistic charged particle beam is reviewed within the context of the theory of plasma wake field excitation. The self-consistent description of the beam dynamics is provided by coupling the Vlasov equation with a Poisson-type equation relating the plasma wake potential to the beam density. An analysis of the beam envelope self-modulation is then carried out and the criteria for the occurrence of the instability are discussed thereby.Comment: This is a 10 pages manuscript which contain 4 figures. This manuscript is recently submitted in 'Nuclear Instruments and Methods in Physics Research Section A' as a proceeding of the conference 'EAAC 2015

Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428

We present results of very-high-energy gamma-ray observations (E > 160 GeV) of two high-frequency-peaked BL Lac (HBL) objects, 1ES 1218+304 and H 1426+428, with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). Both sources are very-high-energy gamma-ray emitters above 100 GeV, detected using ground-based Cherenkov telescopes. STACEE observations of 1ES 1218+304 and H 1426+428 did not produce detections; we present 99% CL flux upper limits for both sources, assuming spectral indices measured mostly at higher energies

Effect of halide-mixing on tolerance factor and charge-carrier dynamics in (CH3NH3PbBr3-xClx) perovskites powders

The authors are highly thankful for the financial support of Higher Education Commission (HEC) Pakistan through the equipment/research grants (6976/Federal/NRPU/R&D/HEC/2017), (20-3071/NRPU/R&D/HEC/13). Author ZS acknowledges HEC for indigenous PhD Fellowship Phase-II, Batch-II, 2013, PIN 213-66018-2PS2-127 and International Research Support Initiative Programme (IRSIP). Author LKJ acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776).This work demonstrates a route to making mixed halide perovskite powders at room temperature by the anti-solvent-assisted crystallization method. Although, mixed halide CH3NH3PbBr3−xClx perovskites have been prepared by different methods, however, to the best of our knowledge the anti-solvent-assisted crystallization method is employed here for the first time to prepare mixed halide CH3NH3PbBr3−xClx perovskite powders. Solution-processed methyl ammonium lead tribromide CH3NH3PbBr3 (x = 0) and different amounts of chloride (Cl) containing mixed halide perovskites (CH3NH3PbBr3−xClx) were prepared for compositions of x = 0.5, 1, 1.25, 1.75. It reveals that bulk CH3NH3PbBr3−xClx samples are highly crystalline and exists in pure single cubic phase with an increased tolerance factor as compared to pure CH3NH3PbBr3. The CH3NH3PbBr3 perovskite has space-group Pm-3 m and a cell parameter of 5.930 Å (volume = 206 Å). The synthesis route adopted here gives access to hybrid perovskites powders with high Cl content and hence enables the band gap to be precisely tuned over a range from 2.26 to 2.49 eV. The powder samples display the subtle shifts in the emission spectra and the photoluminescence kinetics exhibits a decrease in average lifetime by increasing the Cl contents due to the presence of trap states in the structures that encourage non-radiative recombination of charge carrier. Conventionally, the CH3NH3PbBr3-based inverted solar cell architecture is prepared via mixing of the CH3NH3Br and PbBr2 precursors. In contrast, herein, the precursor solutions are directly prepared from the CH3NH3PbBr3 powder and the active layer of the inverted perovskite solar cells are then spin coated using this solution. The high Voc value of the fabricated solar cells potentially makes it a promising candidate for tandem photovoltaic, photocatalytic water splitting, and semi-transparent photovoltaic applications.PostprintPostprintPeer reviewe

Taking the detour

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115976/1/jhm2424.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115976/2/jhm2424-sup-0001-suppinfo.pd

Hierarchical Control Implementation for Meshed AC/Multi-terminal DC Grids with Offshore Windfarms Integration

Although the integration of meshed multi-terminal direct current (MTDC) grids with the existing AC grid has some added economic advantages, significant challenges are encountered in such systems. One of the major challenges is ensuring secure and optimal operation of the combined AC/MTDC grid considering the stability requirements of AC and DC grids at different operating conditions. This paper presents the implementation of hierarchical control for the combined AC/MTDC grid. The hierarchical control is based on the well-established three-layered control of the AC power system, comprising primary, secondary, and tertiary controls. A set of appropriate control methods are proposed for the primary, secondary, and tertiary control layers to accomplish the identified requirements for secure and optimal operation of the combined AC/MTDC grid

Dietary isoflavone and the risk of colorectal adenoma: a case–control study in Japan

We conducted a case–control study in a Japanese population to investigate the association between dietary isoflavone intake and the risk of colorectal adenoma. Participants who underwent magnifying colonoscopy with dye spreading as part of a cancer screening programme responded to a self-administered questionnaire, which included lifestyle information and intake of 145 food items, before the colonoscopy. A total of 721 case and 697 control subjects were enrolled. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models. We found a significant inverse association between dietary isoflavone intake and the risk of colorectal adenoma in men and women combined. However, the inverse association was not linear; rather, all quartiles above the first showed a similar decrease in risk, with multivariable-adjusted ORs and 95% CIs compared with the lowest quartile of 0.77 (0.57–1.04), 0.76 (0.56–1.02) and 0.70 (0.51–0.96) in the second, third and highest quartiles, respectively (P for trend=0.03). Of interest, the observed association was more prominent in women than in men. The observed ceiling effect associated with higher isoflavone intake suggests that a lower intake of dietary isoflavone might be associated with an increased risk of colorectal adenoma in Japanese populations

Can the Non-pneumatic Anti-Shock Garment (NASG) reduce adverse maternal outcomes from postpartum hemorrhage? Evidence from Egypt and Nigeria

<p>Abstract</p> <p>Background</p> <p>Postpartum hemorrhage (PPH) is the leading cause of maternal mortality and severe maternal morbidity. The Non-pneumatic Anti-Shock Garment (NASG), a first-aid lower-body compression device, may decrease adverse outcomes from obstetric hemorrhage. This article is the first to report the effect of the NASG for PPH.</p> <p>Methods</p> <p>This pre-intervention/NASG study of 854 women was conducted in four referral facilities in Nigeria and two in Egypt between 2004-2008. Entry criteria were women with PPH due to uterine atony, retained placenta, ruptured uterus, vaginal or cervical lacerations or placenta accreta with estimated blood loss of ≥ 750 mL and one clinical sign of shock. Differences in demographics, conditions on study entry, treatment and outcomes were examined. The Wilcoxon rank-sum test and relative risks with 95% confidence intervals were calculated for primary outcomes - measured blood loss, emergency hysterectomy, mortality, morbidity (each individually), and a combined variable, "adverse outcomes", defined as severe morbidity and mortality. A multiple logistic regression model was fitted to test the independent association between the NASG and the combined severe morbidity and mortality outcome.</p> <p>Results</p> <p>Measured blood loss decreased by 50% between phases; women experienced 400 mL of median blood loss after study entry in the pre-intervention and 200 mL in the NASG phase (p < 0.0001). As individual outcomes, mortality decreased from 9% pre-intervention to 3.1% in the NASG phase (RR 0.35, 95% CI 0.19-0.62); severe morbidity decreased from 4.2% to 1%, in the NASG phase (RR 0.24, 95% CI 0.09-0.67). As a combination, "adverse outcomes," decreased from 12.8% to 4.1% in the NASG phase (RR 0.32, 95% CI 0.19-0.53). In a multiple logistic regression model, the NASG was associated with the combined outcome of severe maternal morbidity and mortality (OR 0.42, 95% CI 0.18-0.99).</p> <p>Conclusion</p> <p>In this non-randomized study, in which bias is inherent, the NASG showed promise for reducing blood loss, emergency hysterectomy, morbidity and mortality associated with PPH in referral facilities in Egypt and Nigeria.</p

Incremental Non-Rigid Structure-from-Motion with Unknown Focal Length

The perspective camera and the isometric surface prior have recently gathered increased attention for Non-Rigid Structure-from-Motion (NRSfM). Despite the recent progress, several challenges remain, particularly the computational complexity and the unknown camera focal length. In this paper we present a method for incremental Non-Rigid Structure-from-Motion (NRSfM) with the perspective camera model and the isometric surface prior with unknown focal length. In the template-based case, we provide a method to estimate four parameters of the camera intrinsics. For the template-less scenario of NRSfM, we propose a method to upgrade reconstructions obtained for one focal length to another based on local rigidity and the so-called Maximum Depth Heuristics (MDH). On its basis we propose a method to simultaneously recover the focal length and the non-rigid shapes. We further solve the problem of incorporating a large number of points and adding more views in MDH-based NRSfM and efficiently solve them with Second-Order Cone Programming (SOCP). This does not require any shape initialization and produces results orders of times faster than many methods. We provide evaluations on standard sequences with ground-truth and qualitative reconstructions on challenging YouTube videos. These evaluations show that our method performs better in both speed and accuracy than the state of the art.Comment: ECCV 201

Trapped in the prison of the mind: notions of climate-induced (im)mobility decision-making and wellbeing from an urban informal settlement in Bangladesh

The concept of Trapped Populations has until date mainly referred to people ‘trapped’ in environmentally high-risk rural areas due to economic constraints. This article attempts to widen our understanding of the concept by investigating climate-induced socio-psychological immobility and its link to Internally Displaced People’s (IDPs) wellbeing in a slum of Dhaka. People migrated here due to environmental changes back on Bhola Island and named the settlement Bhola Slum after their home. In this way, many found themselves ‘immobile’ after having been mobile—unable to move back home, and unable to move to other parts of Dhaka, Bangladesh, or beyond. The analysis incorporates the emotional and psychosocial aspects of the diverse immobility states. Mind and emotion are vital to better understand people’s (im)mobility decision-making and wellbeing status. The study applies an innovative and interdisciplinary methodological approach combining Q-methodology and discourse analysis (DA). This mixed-method illustrates a replicable approach to capture the complex state of climate-induced (im)mobility and its interlinkages to people’s wellbeing. People reported facing non-economic losses due to the move, such as identity, honour, sense of belonging and mental health. These psychosocial processes helped explain why some people ended up ‘trapped’ or immobile. The psychosocial constraints paralysed them mentally, as well as geographically. More empirical evidence on how climate change influences people’s wellbeing and mental health will be important to provide us with insights in how to best support vulnerable people having faced climatic impacts, and build more sustainable climate policy frameworks