Boron arsenide thin film solar cell development. Quarterly report No. 1

A large portion of the effort expended in the first quarter was devoted to the design, assembly, and testing of the film growth apparatus. The reactor has been completed and tested by depositing boron from diborane gas onto heated quartz substrates. The objective of this effort was to achieve film growth, which has been accomplished. Within the last month, attempts to grow boron arsenide films have been made by introducing both diborane and arsine into the reactor. Thin films have been grown on quartz and sapphire (alumina) substrates. Variations in film thickness, composition, degree of crystallinity, and conductivity have been observed as a result of variation of the deposition parameters, such as type and flow rate of carrier gases, substrate temperature, and substrate materials. X-ray analysis of several samples indicates that films containing boron and arsenic have been grown. No crystalline films have been produced to date. Electrical and optical measurements indicate some correlation between at least one of the films grown and the results achieved by Chu, et al. on BAs. Thus far, the electrical conductivity, film topography, optical absorption, index of refraction, impurity type, and photo-conductivity have been investigated on one sample. This material appears to be B/sub x/As/sub y/ and could be BAs. Further investigations will be required to be conclusive

Characteristics of the Moveable Middle: Opportunities Among Adults Open to COVID-19 Vaccination

Introduction: Focusing on subpopulations that express the intention to receive a COVID-19 vaccination but are unvaccinated may improve the yield of COVID-19 vaccination efforts. Methods: A nationally representative sample of 789,658 U.S. adults aged ≥18 years participated in the National Immunization Survey Adult COVID Module from May 2021 to April 2022. The survey assessed respondents’ COVID-19 vaccination status and intent by demographic characteristics (age, urbanicity, educational attainment, region, insurance, income, and race/ethnicity). This study compared composition and within-group estimates of those who responded that they definitely or probably will get vaccinated or are unsure (moveable middle) from the first and last month of data collection. Results: Because vaccination uptake increased over the study period, the moveable middle declined among persons aged ≥18 years. Adults aged 18–39 years and suburban residents comprised most of the moveable middle in April 2022. Groups with the largest moveable middles in April 2022 included persons with no insurance (10%), those aged 18–29 years (8%), and those with incomes below poverty (8%), followed by non-Hispanic Native Hawaiian or other Pacific Islander (7%), non-Hispanic multiple or other race (6%), non-Hispanic American Indian or Alaska Native persons (6%), non-Hispanic Black or African American persons (6%), those with below high school education (6%), those with high school education (5%), and those aged 30–39 years (5%). Conclusions: A sizable percentage of adults open to receiving COVID-19 vaccination remain in several demographic groups. Emphasizing engagement of persons who are unvaccinated in some racial/ethnic groups, aged 18–39 years, without health insurance, or with lower income may reach more persons open to vaccination

Genome-wide Analyses Identify KIF5A as a Novel ALS Gene

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

Pacioli 18; Proceedings of the 18th international workshop on micro-economic databases in agriculture

The international Pacioli network shares knowledge on the management and use of agricultural micro-economic databases (such as Farm Accountancy Data Networks). Each year a workshop is organised by LEI, part of Wageningen UR, in close collaboration with a local organiser. The Pacioli 18 workshop took place in Ghent, Belgium, in September 2010

Boron arsenide thin film solar cell development. Final report

Pyrolytic decomposition of diborane and arsine has been used in attempts to grow polycrystalline BAs films. This method, however, produced only amorphous films for deposition temperatures below 920/sup 0/C and polycrystalline boron subarsenide (B/sub 12/As/sub 2/) flms for deposition temperatures above this value. The amorphous films have been determined to have a significant arsenic content but the actual stoichiometry was not obtained. The films were adherent on single crystal sapphire (0001), (111) silicon, (0001) SiC, and polycrystalline SiC but were found not to be adherent to substrates of fused quartz, tungsten, and molybdenum. It was also found that all films deposited above 650/sup 0/C were p-type while those deposited below 600/sup 0/C were usually n-type. Polycrystalline BAs and B/sub 12/As/sub 2/ was produced by reaction of the elements in a closed tube. The amorphous films showed an indirect or non-direct optical bandgap from 1.0 to 1.7 eV with the most probable values between 1.2 to 1.4 eV. The crystalline BAs powder shows a bandgap near 1.0 eV. Photoconductance time constants have been measured for films deposited on (0001) sapphire and (0001) SiC. Attempts at doping the amorphous films were generally unsuccessful. A polycrystalline powder sample was successfully doped with sulfur. Attempts were made to produce a Schottky barrier diode by evaporating Al dots onto an amorphous film on graphite without a post-evaporation anneal. An MIS structure was also attempted by baking an amorphous film in air at 280/sup 0/C before evaporation of aluminum. Although nonlinear characteristics were obtained, none of the devices showed any photovoltaic response. A p-type amorphous film was deposited on an n-type silicon substrate to form a p-n heterojunction. This device did exhibit a photovoltaic response but it is believed that the photogeneration was occurring primarily in the silicon substrate