Laser-driven acceleration of quasi-monoenergetic, near-collimated titanium ions via a transparency-enhanced acceleration scheme

Laser-driven ion acceleration has been an active research area in the past two decades with the prospects of designing novel and compact ion accelerators. Many potential applications in science and industry require high-quality, energetic ion beams with low divergence and narrow energy spread. Intense laser ion acceleration research strives to meet these challenges and may provide high charge state beams, with some successes for carbon and lighter ions. Here we demonstrate the generation of well collimated, quasi-monoenergetic titanium ions with energies ∼145 and 180 MeV in experiments using the high-contrast(<10-9) and high-intensity (6× 1020 W cm-2) Trident laser and ultra-Thin (∼100 nm) titanium foil targets. Numerical simulations show that the foils become transparent to the laser pulses, undergoing relativistically induced transparency (RIT), resulting in a two-stage acceleration process which lasts until ∼2 ps after the onset of RIT. Such long acceleration time in the self-generated electric fields in the expanding plasma enables the formation of the quasi-monoenergetic peaks. This work contributes to the better understanding of the acceleration of heavier ions in the RIT regime, towards the development of next generation laser-based ion accelerators for various applications

Iodine chemistry in the troposphere and its effect on ozone

Despite the potential influence of iodine chemistry on the oxidizing capacity of the troposphere, reactive iodine distributions and their impact on tropospheric ozone remain almost unexplored aspects of the global atmosphere. Here we present a comprehensive global modelling experiment aimed at estimating lower and upper limits of the inorganic iodine burden and its impact on tropospheric ozone. Two sets of simulations without and with the photolysis of IxOy oxides (i.e. I2O2, I2O3 and I2O4) were conducted to define the range of inorganic iodine loading, partitioning and impact in the troposphere. Our results show that the most abundant daytime iodine species throughout the middle to upper troposphere is atomic iodine, with an annual average tropical abundance of (0.15-0.55) pptv. We propose the existence of a "tropical ring of atomic iodine" that peaks in the tropical upper troposphere (∼11-14 km) at the equator and extends to the sub-tropics (30°N-30°S). Annual average daytime I = IO ratios larger than 3 are modelled within the tropics, reaching ratios up to ∼20 during vigorous uplift events within strong convective regions. We calculate that the integrated contribution of catalytic iodine reactions to the total rate of tropospheric ozone loss (IOx Loss) is 2-5 times larger than the combined bromine and chlorine cycles. When IxOy photolysis is included, IOx Loss represents an upper limit of approximately 27, 14 and 27% of the tropical annual ozone loss for the marine boundary layer (MBL), free troposphere (FT) and upper troposphere (UT), respectively, while the lower limit throughout the tropical troposphere is ∼9 %. Our results indicate that iodine is the second strongest ozone-depleting family throughout the global marine UT and in the tropical MBL. We suggest that (i) iodine sources and its chemistry need to be included in global tropospheric chemistry models, (ii) experimental programs designed to quantify the iodine budget in the troposphere should include a strategy for the measurement of atomic I, and (iii) laboratory programs are needed to characterize the photochemistry of higher iodine oxides to determine their atmospheric fate since they can potentially dominate halogen-catalysed ozone destruction in the troposphere

An Accurate Data Preparation Approach for the Prediction of Mortality in ACLF Patients using the CANONIC Dataset

The incidence of chronic liver disease has increased in Europe and can lead to Acute on Chronic Liver Failure (ACLF) which is associated with high levels of mortality due to multisystem organ failure. The characteristics of the ACLF patients can change very rapidly within a short period of time. Continuous assessment of their recovery status is critical for clinicians to adjust and deliver effective treatment. The aim of this paper is to validate the usefulness of a data preparation approach by combining different criteria to replace missing values, balance target-class variables, select useful patient characteristics and optimise hyperparameters of machine learning models for the prediction of ACLF associated mortality rates. A key step in the data preparation is a feature selection Mutual Information (MI) based multivariate approach to build smaller, and yet equally and in some cases more informative, subsets of patient characteristics than those frequently proposed for the prediction of mortality, from patients with ACLF in the CANONIC dataset. The usefulness of the data preparation approach proposed to predict mortality was evaluated by training the XGBoost and Logistic Regression models with the prepared data. Evaluations of the models trained using a test set provided evidence of an overall high accuracy in the prediction of the mortality rates of patients for days after their diagnosis, and in some cases even higher when reduced and more informative subsets of patient characteristics were found

Super-resolution far-field ghost imaging via compressive sampling

Much more image details can be resolved by improving the system's imaging resolution and enhancing the resolution beyond the system's Rayleigh diffraction limit is generally called super-resolution. By combining the sparse prior property of images with the ghost imaging method, we demonstrated experimentally that super-resolution imaging can be nonlocally achieved in the far field even without looking at the object. Physical explanation of super-resolution ghost imaging via compressive sampling and its potential applications are also discussed.Comment: 4pages,4figure

A magnetic shift register with out-of-plane magnetized layers

Using out-of-plane magnetized layers, a lateral shift register made from discrete elements is demonstrated. By carefully designing the in-plane shape of the elements which make up the shift register, both the position of nucleation of new domains and the coercivity of the element can be controlled. The dipole field from a neighbouring element placed tens of nanometers away creates a bias field on the nucleation site, which can be used to create a NOT gate. By chaining these NOT gates together, a shift register can be created where data bits consisting of neighbouring layers with aligned magnetization are propagated synchronously under a symmetric applied magnetic field. The operation of a 16 element shift register is shown, including field coupled data injection.This research is funded by the European Community under the Seventh Framework Program ERC Contract No. 247368: 3SPIN, and by EMRP JRP EXL04 SpinCal. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the EU. AB acknowledges DTA funding from the EPSRC. A.F.-P. acknowledges support from the EPSRC Early Career Fellowship EP/M008517/1 and a Winton Fellowship

Marine biogenic emissions of benzene and toluene and their contribution to secondary organic aerosols over the polar oceans

Reactive trace gas emissions from the polar oceans are poorly characterized, even though their effects on atmospheric chemistry and aerosol formation are crucial for assessing current and preindustrial aerosol forcing on climate. Here, we present seawater and atmospheric measurements of benzene and toluene, two gases typically associated with pollution, in the remote Southern Ocean and the Arctic marginal ice zone. Their distribution suggests a marine biogenic source. Calculated emission fluxes were 0.023 ± 0.030 (benzene) and 0.039 ± 0.036 (toluene) and 0.023 ± 0.028 (benzene) and 0.034 ± 0.041 (toluene) μmol m−2 day−1 for the Southern Ocean and the Arctic, respectively. Including these average emissions in a chemistry-climate model increased secondary organic aerosol mass concentrations only by 0.1% over the Arctic but by 7.7% over the Southern Ocean, with transient episodes of up to 77.3%. Climate models should consider the hitherto overlooked emissions of benzene and toluene from the polar oceans

Reliability and Validity of the Ethiopian Version of the Hospital Anxiety and Depression Scale (HADS) in HIV Infected Patients

The hospital anxiety and depression scale (HADS) is a widely used instrument for evaluating psychological distress from anxiety and depression. HADS has not yet been validated in Ethiopia. The aim of this study was to evaluate the reliability and validity of the Amharic (Ethiopian language) version of HADs among HIV infected patients.The translated scale was administered to 302 HIV/AIDS patients on follow up for and taking anti-retroviral treatment. Consistency assessment was conducted using Cronbach's alpha, test-retest reliability using intra-class correlation coefficients (ICC). Construct validity was examined using principal components analysis (PCA). Parallel analysis, Kaiser's criterion and the scree test were used for factor extraction.The internal consistency was 0.78 for the anxiety, 0.76 for depression subscales and 0.87 for the full scale of HADS. The intra-class correlation coefficient (ICC) was 80%, 86%, and 84% for the anxiety and depression subscales, and total score respectively. PCA revealed a one dimensional scale.This preliminary validation study of the Ethiopian version of the HADs indicates that it has promising acceptability, reliability and validity. The adopted scale has a single underlying dimension as indicated by Razavi's model. The HADS can be used to examine psychological distress in HIV infected patients. Findings are discussed and recommendations made

The Impact of Histological Subtype on the Incidence, Timing, and Patterns of Recurrence in Patients with Renal Cell Carcinoma After Surgery-Results from RECUR Consortium

Background: Current follow-up strategies for patients with renal cell carcinoma (RCC) after curative surgery rely mainly on risk models and the treatment delivered, regardless of the histological subtype. Objective: To determine the impact of RCC histological subtype on recurrence and to examine the incidence, pattern, and timing of recurrences to improve follow-up recommendations. Design, setting, and participants: This study included consecutive patients treated surgically with curative intention (ie, radical and partial nephrectomy) for non-metastatic RCC (cT1-4, M0) between January 2006 and December 2011 across 15 centres from 10 countries, as part of the euRopEan association of urology renal cell carcinoma guidelines panel Collaborative multicenter consortium for the studies of follow-Up and recurrence patterns in Radically treated renal cell carcinoma patients (RECUR) database project. Outcome measurements and statistical analysis: The impact of histological subtype (ie, clear cell RCC [ccRCC], papillary RCC [pRCC], and chromophobe RCC [chRCC]) on recurrence-free survival (RFS) was assessed via univariate and multivariate analyses, adjusting for potential interactions with important variables (stage, grade, risk score, etc.) Patterns of recurrence for all histological subtypes were compared according to recurrence site and risk criteria. Results and limitations: Of the 3331 patients, 62.2% underwent radical nephrectomy and 37.8% partial nephrectomy. A total of 2565 patients (77.0%) had ccRCC, 535 (16.1%) had pRCC, and 231 (6.9%) had chRCC. The median postoperative follow-up period was 61.7 (interquartile range: 47-83) mo. Patients with ccRCC had significantly poorer 5-yr RFS than patients with pRCC and chRCC (78% vs 86% vs 91%, p = 0.001). The most common sites of recurrence for ccRCC were the lung and bone. Intermediate-/high-risk pRCC patients had an increased rate of lymphatic recurrence, both mediastinal and retroperitoneal, while recurrence in chRCC was rare (8.2%), associated with higher stage and positive margins, and predominantly in the liver and bone. Limitations include the retrospective nature of the study. Conclusions: The main histological subtypes of RCC exhibit a distinct pattern and dynamics of recurrence. Results suggest that intermediate- to high-risk pRCC may benefit from cross-sectional abdominal imaging every 6 mo until 2 yr after surgery, while routine imaging might be abandoned for chRCC except for abdominal computed tomography in patients with advanced tumour stage or positive margins. Patient summary: In this analysis of a large database from 15 countries around Europe, we found that the main histological subtypes of renal cell carcinoma have a distinct pattern and dynamics of recurrence. Patients should be followed differently according to subtype and risk score. (C) 2020 Published by Elsevier B.V. on behalf of European Association of Urology.Peer reviewe

The Role of Natural Halogens in Global Tropospheric Ozone Chemistry and Budget Under Different 21st Century Climate Scenarios

Funder: NSFFunder: Office of Science of the US Department of EnergyFunder: PICT‐2016‐0714 (ANPCyT)Funder: i‐COOP‐B20331 (CSIC + CONICET)Abstract: Tropospheric ozone ( O 3 ) is an important greenhouse gas and a surface pollutant. The future evolution of O 3 abundances and chemical processing are uncertain due to a changing climate, socioeconomic developments, and missing chemistry in global models. Here, we use an Earth System Model with natural halogen chemistry to investigate the changes in the O 3 budget over the 21st century following Representative Concentration Pathway (RCP)6.0 and RCP8.5 climate scenarios. Our results indicate that the global tropospheric O 3 net chemical change (NCC, chemical gross production minus destruction) will decrease ∼ 50 % , notwithstanding increasing or decreasing trends in ozone production and loss. However, a wide range of surface NCC variations (from −60 % to 150 % ) are projected over polluted regions with stringent abatements in O 3 precursor emissions. Water vapor and iodine are found to be key drivers of future tropospheric O 3 destruction, while the largest changes in O 3 production are determined by the future evolution of peroxy radicals. We show that natural halogens, currently not considered in climate models, significantly impact on the present‐day and future global O 3 burden reducing ∼ 30–35 Tg (11–15 % ) of tropospheric ozone throughout the 21st century regardless of the RCP scenario considered. This highlights the importance of including natural halogen chemistry in climate model projections of future tropospheric ozone