Final Measurement of the

This Letter reports one of the most precise measurements to date of the antineutrino spectrum from a purely ^{235}U-fueled reactor, made with the final dataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By extracting information from previously unused detector segments, this analysis effectively doubles the statistics of the previous PROSPECT measurement. The reconstructed energy spectrum is unfolded into antineutrino energy and compared with both the Huber-Mueller model and a spectrum from a commercial reactor burning multiple fuel isotopes. A local excess over the model is observed in the 5-7 MeV energy region. Comparison of the PROSPECT results with those from commercial reactors provides new constraints on the origin of this excess, disfavoring at 2.0 and 3.7 standard deviations the hypotheses that antineutrinos from ^{235}U are solely responsible and noncontributors to the excess observed at commercial reactors, respectively.

Joint Measurement of the

The PROSPECT and STEREO collaborations present a combined measurement of the pure ^{235}U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ^{2}/ndf=24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This ν[over ¯]_{e} energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ^{2} value is improved, corresponding to a 2.4σ significance.

Life during the pandemic: an international photo-elicitation study with medical students.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic is a global event with unprecedented impact on individuals and communities around the world. The purpose of this study is to use a modified photo-elicitation methodology to examine the impact of the COVID-19 pandemic on the lives of medical students and their communities around the world. METHODS: Participating medical students were asked to take photographs for 14 days. In lieu of an interview, which is customary for photo-elicitation projects, participants were asked to share a reflection (a paragraph or two) for each photograph they contributed to the study. RESULTS: Between April 27th, 2020 and May 11th, 2020 26 students from 19 medical schools across 13 countries shared photographs and reflections. Qualitative analysis of written reflections revealed that medical students felt the impact of the pandemic on several levels 1) individual, 2) interpersonal, 3) educational, and 4) societal. CONCLUSIONS: The COVID-19 pandemic has impacted the lives of medical students on multiple levels. As individuals, students felt emotional distress but found resilience through physical activity and the establishment of new routines. Many students felt isolated as their interpersonal relationships were confined due to social distancing measures. These feelings could be combated with new educational initiatives focused on group collaboration. Lastly, students reflecting on the larger societal implications were concerned with the economic ramifications of the virus and its impact on their future. This study brought together students from several different countries to engage in an applied learning program as a model for equitable global health research.

Measurement of the Antineutrino Spectrum from

This Letter reports the first measurement of the ^{235}U ν[over ¯]_{e} energy spectrum by PROSPECT, the Precision Reactor Oscillation and Spectrum experiment, operating 7.9 m from the 85 MW_{th} highly enriched uranium (HEU) High Flux Isotope Reactor. With a surface-based, segmented detector, PROSPECT has observed 31678±304(stat) ν[over ¯]_{e}-induced inverse beta decays, the largest sample from HEU fission to date, 99% of which are attributed to ^{235}U. Despite broad agreement, comparison of the Huber ^{235}U model to the measured spectrum produces a χ^{2}/ndf=51.4/31, driven primarily by deviations in two localized energy regions. The measured ^{235}U spectrum shape is consistent with a deviation relative to prediction equal in size to that observed at low-enriched uranium power reactors in the ν[over ¯]_{e} energy region of 5-7 MeV.

First Search for Short-Baseline Neutrino Oscillations at HFIR with PROSPECT.

This Letter reports the first scientific results from the observation of antineutrinos emitted by fission products of ^{235}U at the High Flux Isotope Reactor. PROSPECT, the Precision Reactor Oscillation and Spectrum Experiment, consists of a segmented 4 ton ^{6}Li-doped liquid scintillator detector covering a baseline range of 7-9 m from the reactor and operating under less than 1 m water equivalent overburden. Data collected during 33 live days of reactor operation at a nominal power of 85 MW yield a detection of 25 461±283 (stat) inverse beta decays. Observation of reactor antineutrinos can be achieved in PROSPECT at 5σ statistical significance within 2 h of on-surface reactor-on data taking. A reactor model independent analysis of the inverse beta decay prompt energy spectrum as a function of baseline constrains significant portions of the previously allowed sterile neutrino oscillation parameter space at 95% confidence level and disfavors the best fit of the reactor antineutrino anomaly at 2.2σ confidence level.

Nonfuel Antineutrino Contributions in the High Flux Isotope Reactor.

Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties becoming lower than those from theory, carefully considering all sources of ν ¯ e is important when making theoretical predictions. One source of ν ¯ e that is often neglected arises from the irradiation of the nonfuel materials in reactors. The ν ¯ e rates and energies from these sources vary widely based on the reactor type, configuration, and sampling stage during the reactor cycle and have to be carefully considered for each experiment independently. In this article, we present a formalism for selecting the possible ν ¯ e sources arising from the neutron captures on reactor and target materials. We apply this formalism to the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the ν ¯ e source for the the Precision Reactor Oscillation and Spectrum Measurement (PROSPECT) experiment. Overall, we observe that the nonfuel ν ¯ e contributions from HFIR to PROSPECT amount to 1% above the inverse beta decay threshold with a maximum contribution of 9% in the 1.8-2.0 MeV range. Nonfuel contributions can be particularly high for research reactors like HFIR because of the choice of structural and reflector material in addition to the intentional irradiation of target material for isotope production. We show that typical commercial pressurized water reactors fueled with low-enriched uranium will have significantly smaller nonfuel ν ¯ e contribution.

Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan).

An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing (210)Po and (137)Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of (210)Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of (210)Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (microSv/yr) in carnivores, omnivores and herbivores, respectively, for (137)Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For (210)Po, it was found to be 3.47, 4.81 and 4.14 (microSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of (137)Cs is negligible compared to (210)Po.

A new Certified Reference Material for radionuclides in Irish sea sediment (IAEA-385).

A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.

Coronary heart disease prevention in women: focus on lipids.

Coronary heart disease (CHD) remains an urgent and leading threat to women's health and well-being. Clinical trials have demonstrated a clear cut benefit of low density lipoprotein cholesterol (LDL-C) lowering in both women as well as men with coronary disease. While the case for primary prevention of CHD with LDL-C lowering is less secure in both men and women, there is little doubt that patients at high risk of CHD, even without a prior history of vascular events, will in the long run benefit from LDL-C lowering. Thus, all available evidence indicates that lipid interventions should be pursued aggressively in both women and men at risk of CHD.

Prevention and treatment of coronary heart disease: who benefits?

Coronary heart disease (CHD) remains a leading cause of morbidity and mortality in the United States, despite our better understanding of the pathobiology of atherosclerosis, our knowledge of risk factors, the widespread availability of inexpensive cholesterol screening, and the availability of effective and well-tolerated cholesterol-lowering agents. Advances in these areas have created controversies regarding who should be screened and treated for primary or secondary prevention of coronary events. The advent of the statin class of lipid-lowering agents represented a major advance, because they are much more effective and better tolerated than previous agents. There is general agreement that patients with hypercholesterolemia and established CHD require treatment for secondary prevention of recurrent coronary events. Primary prevention is controversial in all patient groups except those with diabetes, because their risk of developing CHD is dramatically increased. Postmenopausal women and the elderly are undertreated, whereas young adults may be underdiagnosed and undertreated. Several ongoing trials may resolve the controversies about which patient groups will benefit from different prevention and treatment strategies.

Triglycerides and coronary risk in women and the elderly.

There seems little doubt that triglycerides are causally related to the progress of atherogenesis. Mechanisms for this effect include adverse quantitative and qualitative changes in circulating lipoproteins. In particular, the effects of lower high-density lipoprotein levels and the production by hypertriglyceridemia of small, dense low-density lipoproteins are of great significance. The role of triglyceride-rich remnant particles in atherogenesis is likely important. These remnants, which are lipoproteins rich in both cholesterol and triglycerides, can be shown to produce cholesteryl ester-laden macrophages in vitro and are probably atherogenic in vivo. Triglyceride levels are a significant risk factor for coronary artery disease in women, more so than in men. Triglyceride levels also increase in older patients and continue to be predictors of coronary risk in both men and women older than 65 years. It is unclear whether triglyceride intervention efforts should be directed at lowering triglyceride levels (such as is accomplished with niacin or fibric acid derivatives) or lowering low-density lipoprotein levels in patients with high triglyceride levels, assuming triglyceride levels are only a passive marker of atherosclerotic risk. Until more is known about the precise role of hypertriglyceridemia in atherogenesis in women and older patients, use of triglyceride-lowering drugs should be conservative and limited to those individuals with high triglyceride levels (> 4.5 mmol/L [> 400 mg/dL]) who do not respond to diet modifications and who are at risk of coronary disease either because of a history of vascular disease or the presence of other risk factors.

Effect of long-term moderate physical exercise on plasma lipoproteins. The National Exercise and Heart Disease Project.

As part of the National Exercise and Heart Disease Project, 223 postcoronary men, aged 30 to 64, were randomly assigned to moderate exercise or control groups. Levels of total plasma cholesterol, high- and low-density lipoprotein (HDL and LDL) cholesterol, and triglycerides were measured. At baseline, alcohol intake, weight, and skin-fold thickness but not treadmill work capacity correlated with triglyceride or HDL cholesterol levels. After one year, no clinically important change in lipid levels was observed in either group. Using multiple regression analysis of the combined groups, changes in several independent variables, including work capacity change, were not predictive of changes in lipid levels. Thus, changes in levels of fitness and/or regular exercise did not substantially influence HDL cholesterol or other lipid levels.

Efficacy and safety of pravastatin in African Americans with primary hypercholesterolemia.

BACKGROUND: Coronary artery disease strikes early and may prove particularly severe in persons of African-American descent. Therefore, we studied the lipid-lowering efficacy and safety of pravastatin sodium (20 mg/d), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, in 245 African-American patients with primary hypercholesterolemia. METHODS: After 4 weeks on an American Heart Association phase I low-fat diet, patients were randomized in a double-blind manner to either pravastatin or placebo in a 3:1 ratio. RESULTS: After 12 weeks of pravastatin treatment, low-density lipoprotein cholesterol levels declined 25.8%, total cholesterol levels 20.3%, and triglyceride levels 6.2%, while high-density lipoprotein cholesterol levels remained essentially unchanged. Overall, 72% of pravastatin-treated patients achieved reductions in low-density lipoprotein cholesterol level in excess of 20%, and 44% attained declines in excess of 30% (both P < .01 vs placebo). Pravastatin was generally well tolerated in this population, with one patient (0.5%) exhibiting a reversible myopathy with creatine kinase elevations to 10 times the upper limit of normal. No substantial elevations of aminotransferase levels of two to three times the upper limit of normal occurred in either the pravastatin or the placebo group. Drug compliance was high, exceeding 90%. CONCLUSION: Pravastatin appears to be an effective and safe lipid-lowering agent and is the first 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor to be studied extensively in this underrepresented population.

Cholesterol lowering in the elderly. Results of the Cholesterol Reduction in Seniors Program (CRISP) pilot study.

BACKGROUND: Total and lipoprotein cholesterol levels continue to be predictors of coronary heart disease risk in men and women over 65 years old. Cholesterol-lowering trials, however, while sometimes including such subjects, have not concentrated on this age group. The Cholesterol Reduction in Seniors Program was a five-center pilot study to assess feasibility of recruitment and efficacy of cholesterol lowering in this age group. METHODS: The study was a randomized, double-masked clinical trial with placebo, 20-mg lovastatin, and 40-mg lovastatin arms. Major efforts were made to recruit women and minorities. Participants were followed up for 1 year on a cholesterol-lowering diet plus placebo or study drug. End points were changes in blood lipid levels. Data on other blood chemistry values, as well as quality-of-life measures and coronary heart disease morbidity and mortality, were also collected. RESULTS: Four hundred thirty-one subjects with low-density lipoprotein cholesterol levels greater than 4.1 and less than 5.7 mmol/L (159 and 221 mg/dL) were randomized, of whom 71% were women and 21% were African Americans; the mean age was 71 years. In the 20- and 40-mg lovastatin groups, total cholesterol levels fell 17% and 20%; low-density lipoprotein cholesterol levels fell 24% and 28%; triglyceride levels fell 4.4% and 9.9%, respectively. High-density lipoprotein cholesterol levels rose 7.0% and 9.0%, respectively. No changes were observed in the placebo group. Gender, race, and age did not significantly affect responses. Coronary heart disease morbidity and mortality data were collected but not analyzed for this study. CONCLUSION: Older subjects of both genders and a variety of racial and ethnic groups can be successfully recruited into a cholesterol-lowering trial. Lovastatin has effects similar to those reported in younger subjects in previous controlled trials. There is little advantage to the higher lovastatin daily dose. Side effects were remarkably low in all groups.

Comparison of psyllium hydrophilic mucilloid and cellulose as adjuncts to a prudent diet in the treatment of mild to moderate hypercholesterolemia.

The effects of the administration of 5.1 g of psyllium or placebo (cellulose) twice daily for 16 weeks were compared as adjuncts to a prudent diet in the management of moderate hypercholesterolemia in a parallel, double-blind study. Psyllium decreased the total cholesterol level by 5.6% and the low-density lipoprotein cholesterol level by 8.6%, whereas the levels were unchanged in the placebo group. The high-density lipoprotein cholesterol level decreased during the diet stabilization period in both groups and returned to near-baseline values by week 16. Plasma triglyceride levels did not change substantially in either group. Subject compliance to treatment was greater than 95%. These data suggest that psyllium hydrophilic mucilloid in a twice-daily regimen may be a useful and safe adjunct to a prudent diet in the treatment of moderate hypercholesterolemia.

Effects of unopposed conjugated equine estrogen on lipoprotein composition and apolipoprotein-E distribution.

Administration of conjugated equine estrogen to 31 postmenopausal women for 3 months produced 14.6% and 9.4% decreases in low density lipoprotein cholesterol (LDL-C) and apolipoprotein-B (apoB), and 11.5%, 12.7%, and 9.6% increases in high density lipoprotein cholesterol (HDL-C), apoA-I and apoA-II, respectively. Phospholipids of HDL2 and HDL3 were increased 57.9% and 19.3%, respectively, while relatively small increases in cholesterol of the two subfractions were not significant. Compositions of LDL and HDL and its subfractions were altered substantially with estrogen treatment. The proportion of LDL triglyceride to LDL-C was increased. The phospholipid content in both the HDL2 and HDL3 subfractions (compared to cholesterol) was increased significantly (34.8% and 10.7%, respectively), while the triglyceride content was increased only in the HDL2 subfraction (43.6%). Estrogen use also caused a 9.1% reduction in total apoE levels and a redistribution of apoE to the very low density lipoprotein (VLDL) from the LDL plus HDL fraction, resulting in a significant 19.5% decrease in apoE in the LDL plus HDL fraction. Changes in apoE in the VLDL fraction were associated positively with changes in the cholesterol levels of the VLDL fraction and inversely with changes in LDL-C and apoB levels, while changes in apoE in the LDL plus HDL fraction were associated positively with changes in the levels of HDL-C. Thus, estrogen causes alterations in lipoproteins that could potentially affect their metabolism and/or function.

Hypocholesterolemic effects of a dietary fiber supplement.

The cholesterol-lowering effects of a fiber supplement were evaluated in patients with mild to moderate hypercholesterolemia. After a 9-wk diet stabilization period, patients were randomly assigned to treatment with 10 or 20 g/d of the fiber supplement or with a matching placebo. Among patients who completed the 15-wk treatment period, total cholesterol, LDL cholesterol, and the ratio of LDL to HDL (LDL/HDL) were significantly reduced (P < 0.05) for the 10- (n = 40) and 20-g/d (n = 39) groups compared with the placebo group (n = 48). In the placebo group and 10- and 20-g/d groups, the percent changes in total cholesterol were 0.4%, -5.8%, and -4.9%, in LDL cholesterol were -0.4%, -8.1%, and -7.3%, and in LDL/HDL were 1.0%, -5.6%, and -8.7%, respectively. The fiber supplement had no significant effects (P > 0.05) on HDL cholesterol or triglycerides. The changes in lipoprotein concentrations could not be attributed to changes in diet or body weight because there were no significant changes in these variables during the 15-wk treatment period.

Cholesterol and public policy.

Cholesterol lowering in both primary and secondary prevention has been clearly demonstrated to lower coronary morbidity and, in secondary prevention, to lower coronary mortality as well. Putative dangers of cholesterol lowering remain unproven. Population studies linking low cholesterol to noncoronary mortalities do not demonstrate cause-and-effect relations. In fact, based on current studies, the opposite is more likely to be the case. Neither gender nor age should automatically exclude persons from cholesterol screening. Drug intervention, however, should be used conservatively, particularly in young adults and the elderly. Drugs should be used only after diet and lifestyle interventions have failed. The evidence linking high blood cholesterol to coronary atherosclerosis and cholesterol lowering to its prevention is broad-based and definitive. Concerns about cholesterol lowering and spontaneously low cholesterols should be pursued but should not interfere with the implementation of current public policies to reduce the still heavy burden of atherosclerosis in Western society.

Androgens and women's health: genetic and epidemiologic aspects of lipid metabolism.

Lipoprotein metabolism may be viewed as a process whereby large, triglyceride-carrying particles from the intestine and liver are broken down into smaller cholesterol-enriched lipoprotein particles. In the process, triglyceride is transported from the intestine and liver to adipose and other storage tissues. Androgen appears to affect lipoprotein metabolism in a number of ways. These include: increasing the activity of lipoprotein lipase and hepatic triglyceride lipase, resulting in higher levels of triglyceride in adipose tissue and a drop in total circulating high-density lipoprotein levels, respectively, and decreasing catabolic removal of low-density lipoproteins from circulating plasma. In pre- and postmenopausal women, androgen progestins in some oral contraceptives, especially the older 19-nortestosterone derivatives such as norgestrel, lower high-density lipoprotein and raise low-density lipoprotein levels. Newer 19-nortestosterone derivatives, such as desogestrel and norgestimate, have a lesser effect on circulating lipoproteins. Nonoral androgenic progestins (e.g., subcutaneous norgestrel) have little effect on circulating lipids, however, which indicates the significance of the "first pass" through the liver for oral agents. The effects of androgens on atherogenesis are largely unexplored, although preliminary studies indicate that they may promote the atherogenic process.

Management of postmenopausal women who have hyperlipidemia.

Dyslipoproteinemia is prevalent in women as well as in men. In both, its consequences of premature atherosclerosis and coronary artery disease (CAD) morbidity and mortality are common. Although clinical evidence of the benefits of cholesterol lowering is less abundant in women, it is not entirely absent. As in men, cholesterol lowering in women is associated with a decline in CAD risk and regression of coronary atherosclerosis.