The design of a common lunar lander

The Austin Cynthesis Corporation was formed to respond to a Request for Proposal for the design of a Common Lunar Lander (CLL) capable of carrying lightweight (less than 500 kg), unspecified payload to the moon. This Final Design Report Document includes information on the requirements for the design project; the ideas proposed as solutions to the design problem; the work which has been completed in support of the design effort; justifications, validations, and verifications of decisions made during the project; and suggestions for future work to be done in support of the project. A project schedule, including current status of the items included on the schedule, as well as cost and management summaries is also included

Preliminary Analysis: Am-241 RHU/TEG Electric Power Source for Nanosatellites

No abstract availabl

NACHOS, a CubeSat-Based High-Resolution UV-Visible Hyperspectral Imager for Remote Sensing of Trace Gases: System Overview, Science Objectives, and Preliminary Results

The Nano-satellite Atmospheric Chemistry Hyperspectral Observation System (NACHOS) is a high-throughput (f/2.9), high spectral resolution (1.3 nm optical, 0.57 nm sampling) hyperspectral imager covering the 300-500 nm spectral region with 350 spectral bands. The combined 1.5U instrument payload and 1.5U spacecraft bus comprise a 3U CubeSat. Spectroscopically similar to NASA’s Ozone Monitoring Instrument (OMI), which provides wide-field coverage at ~20 km spatial resolution, NACHOS offers complementary targeted measurements at far higher spatial resolution of ~0.4 km/pixel from 500 km altitude over its 15 ̊ across-track field of view. NACHOS incorporates highly streamlined onboard gas-retrieval algorithms, alleviating the need to routinely downlink massive hyperspectral data cubes. This paper discusses the instrument design, requirements leading to it, preliminary results, and science goals, including monitoring NO2 as a proxy for anthropogenic greenhouse gases, low-level degassing of SO2 and halogen oxides at pre-eruptive volcanoes, and formaldehyde from wildfires. Aiming for an eventual many-satellite constellation providing both high spatial resolution and frequent target revisits, the current NACHOS project is launching two CubeSats, the first already launched to the International Space Station aboard the NG-17 Cygnus vehicle on February 19, 2022 and awaiting deployment to its final orbit in June, and the second launching June 29, 2022

Clinical Performance of the Point-of-Care cobas Liat for Detection of SARS-CoV-2 in 20 Minutes: a Multicenter Study.

Highly accurate testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the point of care (POC) is an unmet diagnostic need in emergency care and time-sensitive outpatient care settings. Reverse transcription-PCR (RT-PCR) technology is the gold standard for SARS-CoV-2 diagnostics. We performed a multisite U.S. study comparing the clinical performance of the first U.S. Food and Drug Administration (FDA)-authorized POC RT-PCR for detection of SARS-CoV-2 in 20 min, the cobas Liat SARS-CoV-2 and influenza A/B nucleic acid test, to the most widely used RT-PCR laboratory test, the cobas 68/8800 SARS-CoV-2 test. Clinical nasopharyngeal swab specimens from 444 patients with 357 evaluable specimens at five U.S. clinical laboratories were enrolled from 21 September 2020 to 23 October 2020. The overall agreement between the Liat and 68/8800 systems for SARS-CoV-2 diagnostics was 98.6% (352/357). Using Liat, positive percent agreement for SARS-CoV-2 was 100% (162/162) and the negative percent agreement was 97.4% (190/195). The Liat is an RT-PCR POC test that provides highly accurate SARS-CoV-2 results in 20 min with performance equivalent to that of high-throughput laboratory molecular testing. Rapid RT-PCR testing at the POC can enable more timely infection control and individual care decisions for coronavirus disease 2019

Learning Progression: Implications for Curriculum and Assessment

This short brief is targeted to policy makers in governments and school districts who may be thinking about learning progressions and the implications for curriculum, teaching, and assessment

Rethinking Learner Progression for the Future

This paper presents arguments for placing the concept of learners’ progression at the centre of thinking about curriculum, pedagogy and assessment

More on the relationship between corporate governance and firm performance in the UK: Evidence from the application of generalized method of moments estimation

YesThis study examines the relationship between corporate governance compliance and firm performance in the UK. We develop a Governance Index and investigate its impact on corporate performance after controlling for potential endogeneity through the use of a more robust methodology, Generalized Method of Moments (GMM) Estimation. Our evidence is based on a sample of 435 non-financial publicly listed firms over the period 1999–2009. In contrast to earlier findings in the UK literature, our results suggest that compliance with corporate governance regulations is not a determinant of corporate performance in the UK. We argue that results from prior studies showing a positive impact of corporate governance on firms’ performance may be biased as they fail to control for potential endogeneity. There may be a possibility of reverse causality in the results of prior studies due to which changes in the internal characteristics of firms may be responsible for the corporate governance compliance and performance relationship. Our findings are based on GMM, which controls for the effects of unobservable heterogeneity, simultaneity and dynamic endogeneity and thus present more robust conclusions as compared to the findings of previously published studies in this area

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements