Active search in intensionally specified structured spaces

We consider an active search problem in intensionally specified structured spaces. The ultimate goal in this setting is to discover structures from structurally different partitions of a fixed but unknown target class. An example of such a process is that of computer-aided de novo drug design. In the past 20 years several Monte Carlo search heuristics have been developed for this process. Motivated by these hand-crafted search heuristics, we devise a Metropolis--Hastings sampling scheme where the acceptance probability is given by a probabilistic surrogate of the target property, modeled with a max entropy conditional model. The surrogate model is updated in each iteration upon the evaluation of a selected structure. The proposed approach is consistent and the empirical evidence indicates that it achieves a large structural variety of discovered targets

CFD Predictions for Transonic Performance of the ERA Hybrid Wing-Body Configuration

A computational study was performed for a Hybrid Wing Body configuration that was focused at transonic cruise performance conditions. In the absence of experimental data, two fully independent computational fluid dynamics analyses were conducted to add confidence to the estimated transonic performance predictions. The primary analysis was performed by Boeing with the structured overset-mesh code OVERFLOW. The secondary analysis was performed by NASA Langley Research Center with the unstructured-mesh code USM3D. Both analyses were performed at full-scale flight conditions and included three configurations customary to drag buildup and interference analysis: a powered complete configuration, the configuration with the nacelle/pylon removed, and the powered nacelle in isolation. The results in this paper are focused primarily on transonic performance up to cruise and through drag rise. Comparisons between the CFD results were very good despite some minor geometric differences in the two analyses

Quantum states of a hydrogen atom adsorbed on Cu(100) and (110) surfaces

Quantum states of a hydrogen atom adsorbed on Cu(100) and Cu(110) are studied theoretically. In calculating eigenenergies and wave functions of hydrogen atom motion, three-dimensional adiabatic potential energy surfaces (PESs) are constructed within density functional theory and the Schrödinger equation for hydrogen atom motion on the PESs is solved by the variation method. The wave function on Cu(100) indicates a localized mode on the hollow (HL) site at the ground state. Wave functions of the first few excited states indicate vibrational modes on the HL site and suggest migration from an HL site to a neighboring HL site over the bridge (BR) site. In the case of Cu(110), the ground state wave function is spread from the short bridge (SB) site and to the pseudothreefold (PT) site. The first few excited states are vibrational modes centered at the SB and long bridge (LB) sites. The excited state wave function of the hydrogen atom motion on Cu(110) show isotope effects as follows. The fourth excited state wave function for the H atom motion shows a localized character on the LB site, and those for D and T atom motion show vibrational modes parallel to the surface. On the other hand, the fifth excited state wave functions for D and T atom motion show localized characters on the LB site and that for H atom motion shows a vibrational mode parallel to the surface. Our calculated eigenenergies of the hydrogen atom motion in excited states on Cu(100) and Cu(110) are fairly in agreement with their corresponding experimental findings

Cellulose nanocrystals crosslinked with sulfosuccinic acid as sustainable proton exchange membranes for electrochemical energy applications

Nanocellulose is a sustainable material which holds promise for many energy-related applications. Here, nanocrystalline cellulose is used to prepare proton exchange membranes (PEMs). Normally, this nanomaterial is highly dispersible in water, preventing its use as an ionomer in many electrochemical applications. To solve this, we utilized a sulfonic acid crosslinker to simultaneously improve the mechanical robustness, water-stability, and proton conductivity (by introducing-SO3− H+ functional groups). The optimization of the proportion of crosslinker used and the crosslinking reaction time resulted in enhanced proton conductivity up to 15 mS/cm (in the fully hydrated state, at 120◦ C). Considering the many advantages, we believe that nanocellulose can act as a sustainable and low-cost alternative to conventional, ecologically problematic, perfluorosulfonic acid ionomers for applications in, e. fuel cells and electrolyzers

A Tale of Two Stories from "Below the Line": Comment Fields at the Guardian

This article analyzes the nature of debate on “below the line” comment fields at the United Kingdom’s Guardian, and how, if at all, such debates are impacting journalism practice. The article combines a content analysis of 3,792 comments across eighty-five articles that focused on the UN Climate Change Summit, with ten interviews with journalists, two with affiliated commentators, plus the community manager. The results suggest a more positive picture than has been found by many existing studies: Debates were often deliberative in nature, and journalists reported that it was positively impacting their practice in several ways, including providing new story leads and enhanced critical reflection. However, citizen–journalist debate was limited. The results are attributed to the normalization of comment fields into everyday journalism practice, extensive support and encouragement from senior management, and a realization that comment fields can actually make the journalists’ life a little easier

The SCAPA LWFA beamline

The Scottish Centre for the Application of Plasma based Accelerators situated at the University of Strathclyde in Glasgow, UK, is coming online. It comprises three radiation shielded concrete bunkers housing a total of seven beamlines and interaction chambers, each driven by one of a pair of high power Ti sapphire laser systems a 350 TW and a 40 TW

Design of a double dipole electron spectrometer

With the increase of laser power at facilities reaching petawatt-level, there is a need for accurate electron beam diagnostics of the laser wakefield accelerator (LWFA), which are becoming important tools for a wide range of applications including high field physics. Electrons in the range of several 10 0s of GeV are expected at these power levels. Precise diagnostic systems are required to enable applications such as advanced radiation sources. Accurate measurement of the energy spread of electron beams will help pave the way towards LWFA based free-electron lasers and plasma based coherent radiation sources. We propose an innovative double dipole spectrometer suitable for characterizing bunches produced using a petawatt class laser

Characterisation of a laser plasma accelerator x-ray source size using a Kirkpatrick-Baez microscope

Laser plasma accelerators are highly versatile and are sources of both radiation and particle beams, with unique properties. The Scottish Centre for Application based Plasma Accelerators (SCAPA) 40 TW and 350 TW laser at the University of Strathclyde has been used to produce both soft and hard x-rays using a laser wakefield accelerator (LWFA). The inherent characteristics of these femtosecond duration pulsed x-rays make them ideal for probing matter and ultrafast imaging applications. To support the development of applications of laser plasma accelerators at the SCAPA facility an adjustable Kirkpatrick-Baez x-ray microscope has been designed to focus 50 eV - 10 KeV x-rays. It is now possible to produce high quality at silicon wafers substrates that can be used for x-ray optics. Platinum-coated (40 nm) silicon wafers have been used in the KB instrument to image the LWFA x-ray source. We simulate the source distribution as part of an investigation to determine the x-ray source size and therefore its transverse coherence and ultimately the peak brilliance. The OASYS SHAODOW-OUI raytracing and wave propagation code has been used to simulate the imaging setup and determine instrument resolution

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049