Fast Neutron Breeder

One of the fundamental reasons for developing methods of power generation utilizing nuclear fission as the heat source is to extend the world\u27s supply of energy resources beyond those available in the conventional fuels; coal, oil and gas. The only naturally occurring isotope which can sustain a chain reaction is U-235. In the fertile materials U-238 and Th-232, there is a possibility of magnifying the supply of nuclear energy by several orders of magnitude. In certain types of reactors, it is possible to produce more fissionable material than is consumed in the production of heat. This phenomenon is called breeding and is the main reason for the effort to develop fast reactors. It is the purpose of this paper to discuss some of the distinguishing characteristics of a fast reactor using as illustration the reactor being developed by Atomic Power Development Associates, Inc. (APDA) for construction by Power Reactor Development Corporation (PRDC) at the Enrico Fermi Atomic Power Plant near Monroe, Michigan

Barriers/Drivers of Diverse Perennial Systems: Policy Recommendations

Despite growing documentation of perennial- and grass-based systems’ importance in addressing many ecological, infrastructural, farmer profitability, and climate concerns, these systems do not predominate on most United States farm and ranch lands. To better understand what impedes their wider adoption, we undertook four focus groups of diverse current and potential farmers using perennial systems. We were especially interested in how these farmers access, or don’t, insurance, credit, and federal programs, identifying patterns among farmers embracing more sustainable practices. Our virtual focus groups comprised 16 farmers in ten states, transecting climate zones and representing both rural and urban production systems and diversity in ethnicity, gender, and farm size. We committed to maintaining participants’ anonymity and paid them a modest stipend. Some clear trends emerged as motivations for adopting perennial farming systems, including their ecosystem benefits to farms and to society, relative simplicity and ease of implementation, and lesser capital requirements for entry. Participants described numerous barriers to adoption, including woody perennials’ longer establishment period before becoming productive and cash-flow challenges during that period. Some farmers experienced a lack of understanding of perennials by federal agency staff and challenges accessing federal programs. Some desired easy-to-access support in navigating agency options and an easier process to appeal agency decisions. Many participants perceived perennials to be inherently risk-reducing, but few considered federal crop insurance useful. Similarly, challenges in accessing credit required many participants to self-finance or grow their operations slowly. Federal conservation programs had served some participants, but farmers of color reported difficulty in accessing them, partly due to agency staff’s restricted hours. Direct markets were easier for some perennial farmers, although time-consuming, but processing delays and impediments could be problematic, including for meat animals grown on managed pasture. Many farmers would profit from technical assistance and nationally-available reliable information on perennial production systems

Perceptions of Women and Men Leaders Following 360‐Degree Feedback Evaluations

In this study, researchers used a customized 360‐degree method to examine the frequency with which 1,546 men and 721 women leaders perceived themselves and were perceived by colleagues as using 10 relational and 10 task‐oriented leadership behaviors, as addressed in the Management‐Leadership Practices Inventory (MLPI). As hypothesized, men and women leaders, as well as their supervisors, employees, and peers, perceived women leaders to employ nine of the 10 relational leadership behaviors significantly more frequently than men leaders. Additionally, the employees' perceptions of their women leaders' use of task‐oriented behaviors were significantly higher when compared to similar assessments from the employees of men leaders. However, the leaders as well as their supervisors and peers perceived men and women leaders' use of task‐oriented behaviors as approximately equal. Broader implications of these findings are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97470/1/21134_ftp.pd

LDL-C Concentrations and the 12-SNP LDL-C Score for Polygenic Hypercholesterolaemia in Self-Reported South Asian, Black and Caribbean Participants of the UK Biobank.

Background: Monogenic familial hypercholesterolaemia (FH) is an autosomal dominant disorder characterised by elevated low-density lipoprotein cholesterol (LDL-C) concentrations due to monogenic mutations in LDLR, APOB, PCSK9, and APOE. Some mutation-negative patients have a polygenic cause for elevated LDL-C due to a burden of common LDL-C-raising alleles, as demonstrated in people of White British (WB) ancestry using a 12-single nucleotide polymorphism (SNP) score. This score has yet to be evaluated in people of South Asian (SA), and Black and Caribbean (BC) ethnicities. Objectives: 1) Compare the LDL-C and 12-SNP score distributions across the three major ethnic groups in the United Kingdom: WB, SA, and BC individuals; 2) compare the association of the 12-SNP score with LDL-C in these groups; 3) evaluate ethnicity-specific and WB 12-SNP score decile cut-off values, applied to SA and BC ethnicities, in predicting LDL-C concentrations and hypercholesterolaemia (LDL-C>4.9 mmol/L). Methods: The United Kingdom Biobank cohort was used to analyse the LDL-C (adjusted for statin use) and 12-SNP score distributions in self-reported WB (n = 353,166), SA (n = 7,016), and BC (n = 7,082) participants. To evaluate WB and ethnicity-specific 12-SNP score deciles, the total dataset was split 50:50 into a training and testing dataset. Regression analyses (logistic and linear) were used to analyse hypercholesterolaemia (LDL-C>4.9 mmol/L) and LDL-C. Findings: The mean (±SD) measured LDL-C differed significantly between the ethnic groups and was highest in WB [3.73 (±0.85) mmol/L], followed by SA [3.57 (±0.86) mmol/L, p < 2.2 × 10-16], and BC [3.42 (±0.90) mmol/L] participants (p < 2.2 × 10-16). There were significant differences in the mean (±SD) 12-SNP score between WB [0.90 (±0.23)] and BC [0.72 (±0.25), p < 2.2 × 10-16], and WB and SA participants [0.86 (±0.19), p < 2.2 × 10-16]. In all three ethnic groups the 12-SNP score was associated with measured LDL-C [R 2 (95% CI): WB = 0.067 (0.065-0.069), BC = 0.080 (0.063-0.097), SA = 0.027 (0.016-0.038)]. The odds ratio and the area under the curve for hypercholesterolaemia were not statistically different when applying ethnicity-specific or WB deciles in all ethnic groups. Interpretation: We provide information on the differences in LDL-C and the 12-SNP score distributions in self-reported WB, SA, and BC individuals of the United Kingdom Biobank. We report the association between the 12-SNP score and LDL-C in these ethnic groups. We evaluate the performance of ethnicity-specific and WB 12-SNP score deciles in predicting LDL-C and hypercholesterolaemia

A Machine Learning Model to Aid Detection of Familial Hypercholesterolemia

Background People with monogenic familial hypercholesterolemia (FH) are at an increased risk of premature coronary heart disease and death. With a prevalence of 1:250, FH is relatively common; but currently there is no population screening strategy in place and most carriers are identified late in life, delaying timely and cost-effective interventions. Objectives The purpose of this study was to derive an algorithm to identify people with suspected monogenic FH for subsequent confirmatory genomic testing and cascade screening. Methods A least absolute shrinkage and selection operator logistic regression model was used to identify predictors that accurately identified people with FH in 139,779 unrelated participants of the UK Biobank. Candidate predictors included information on medical and family history, anthropometric measures, blood biomarkers, and a low-density lipoprotein cholesterol (LDL-C) polygenic score (PGS). Model derivation and evaluation were performed in independent training and testing data. Results A total of 488 FH variant carriers were identified using whole-exome sequencing of the low-density lipoprotein receptor, apolipoprotein B, apolipoprotein E, proprotein convertase subtilisin/kexin type 9 genes. A 14-variable algorithm for FH was derived, with an area under the curve of 0.77 (95% CI: 0.71-0.83), where the top 5 most important variables included triglyceride, LDL-C, apolipoprotein A1 concentrations, self-reported statin use, and LDL-C PGS. Excluding the PGS as a candidate feature resulted in a 9-variable model with a comparable area under the curve: 0.76 (95% CI: 0.71-0.82). Both multivariable models (w/wo the PGS) outperformed screening-prioritization based on LDL-C adjusted for statin use. Conclusions Detecting individuals with FH can be improved by considering additional predictors. This would reduce the sequencing burden in a 2-stage population screening strategy for FH