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.

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.

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.

Relationship between postprandial metabolomics and colon motility in children with constipation.

BACKGROUND: The metabolic pathways associated with colonic motility are unknown. To identify potential metabolic targets for treatment of constipation, we examined the metabolic profile before and after a meal challenge in a cohort of children with constipation and determined its relationship with postprandial colon motility patterns. METHODS: In this prospective study, 187 metabolites were measured by liquid chromatography-mass spectrometry at multiple time points before and after a standardized meal in constipated children undergoing a colon manometry. Postprandial metabolite levels were compared with baseline and also correlated with multiple manometric measurements, including the number, frequency, and amplitude of pressure peaks as well as the motility index (MI). KEY RESULTS: A total of 20 subjects were included (mean age 13.1 ± 3.4 years). No significant metabolite changes were observed at 10 min after the meal, whereas 16 amino acid and 22 lipid metabolites had significant (P < 0.005) postprandial changes, including decreases in methylhistamine, histamine, and GABA, by 60 min. Correlations were observed between normal and abnormal postprandial motility patterns and changes in specific metabolites, including glycerol, carnosine, alanine, asparagine, cytosine, choline, phosphocholine, thyroxine, and triiodothyronine. Interestingly, subjects without the normal postprandial increase in area under the curve (AUC), had markedly increased levels of kynurenic acid and adenosyl-homocysteine. CONCLUSIONS & INFERENCES: This is the first study to examine postprandial metabolic changes in children and also to correlate changes in specific metabolites with colonic motility. The results suggest possible metabolic pathways associated with motility and identify potential targets for the treatment of constipation.

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.

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.

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.

Enhancing drug compliance in lipid-lowering treatment.

Hyperlipidemia and the atherosclerotic conditions that result from it are well recognized as major contributors to coronary heart disease (CHD). Fortunately, several large-scale clinical trials have shown that there are effective treatments that can substantially lower atherogenic lipid levels and thereby reduce the risk of CHD mortality and morbidity. However, duplication of these dramatic trial results can be negatively affected in "real life" clinical practice by an important issue: compliance. No medications will work if patients do not take them. Unfortunately, patients who need lipid-lowering therapy are likely to need it long-term, perhaps for a lifetime. Yet, many do not adhere to the prescribed medication regimen. This article reviews some major studies of compliance for lipid-lowering drugs. The reasons why patients do not take them as prescribed vary: poor education, lack of understanding, cost, provider indifference, and others. Achieving compliance requires a multifaceted approach. It can be enhanced by encouraging patients to talk openly about their medication habits and by convincing them of the long-term benefits of reaching and maintaining target low-density lipoprotein cholesterol levels. Although more studies focusing on compliance specifically regarding CHD are needed, the current literature does provide some guidance. Arch Fam Med. 2000;9:1169-1175

Effect of statins on risk of coronary disease: a meta-analysis of randomized controlled trials.

CONTEXT: Lowering low-density lipoprotein cholesterol (LDL-C) is known to reduce risk of recurrent coronary heart disease in middle-aged men. However, this effect has been uncertain in elderly people and women. OBJECTIVE: To estimate the risk reduction of coronary heart disease and total mortality associated with statin drug treatment, particularly in elderly individuals and women. DATA SOURCES: Trials published in English-language journals were retrieved by searching MEDLINE (1966-December 1998), bibliographies, and authors' reference files. STUDY SELECTION: Studies in which participants were randomized to statin or control treatment for at least 4 years and clinical disease or death was the primary outcome were included in the meta-analysis (5 of 182 initially identified). DATA EXTRACTION: Information on sample size, study drug duration, type and dosage of statin drug, participant characteristics at baseline, reduction in lipids during intervention, and outcomes was abstracted independently by 2 authors (J.H. and S.V.) using a standardized protocol. Disagreements were resolved by consensus. DATA SYNTHESIS: Data from the 5 trials, with 30 817 participants, were included in this meta-analysis. The mean duration of treatment was 5.4 years. Stati n drug treatment was associated with a20% reduction in total cholesterol, 28% reduction in LDL-C, 13% reduction in triglycerides, and 5% increase in high-density lipoprotein cholesterol. Overall, statin drug treatment reduced risk 31 % in major coronary events (95% confidence interval [CI], 26%-36%) and 21 % in all-cause mortality (95% CI, 14%-28%). The risk reduction in major coronary events was similar between women (29%; 95% Cl, 13 %-42 %) and men (31 %; 95% CI, 26%-35%), and between persons aged at least 65 years (32%; 95% CI, 23%-39%) and persons younger than 65 years (31 %; 95% CI, 24%-36%). CONCLUSIONS: Our meta-analysis indicates that reduction in LDL-C associated with statin drug treatment decreases the risk of coronary heart disease and all-cause mortality. The risk reduction was similar for men and women and for elderly and middle-aged persons.

Future cardiovascular end point studies: where will the research take us?

Coronary artery disease is the most common cause of death in the world. Emerging concepts of atherosclerosis imply that atherosclerosis is a diffuse disease, and cannot be definitively treated with local, anatomic interventions, such as coronary artery bypass graft surgery or angioplasty. Cholesterol lowering, on the other hand, has been shown to dramatically lower the rate of both morbid and mortal coronary events. In trials with new statin drugs, coronary risk has been lowered by approximately 30%. Additional risk reduction will require other approaches, including (1) intervention for other risk factors, (2) more aggressive cholesterol lowering, or (3) increased attention to primary prevention. The last requires a combination of public health measures to change harmful diet and life-style patterns as well as case findings to identify and treat at-risk subjects. For all these approaches, measures that will increase compliance by both physicians and patients to regimens with proven benefits are required.

Academic medicine and managed care: seeking common ground.

The authors report the highlights of a one-day symposium, "Academic Medicine and Managed Care: Seeking Common Ground," sponsored in early 1997 by Tulane University Medical Center. The meeting was held to foster better understanding of the gap between managed care organizations (MCOs) and academic health centers (AHCs) and to define their common ground. There were 62 participants, mainly executives froin AHCs and MCOs, plus government officials and policy researchers interested in the interface of academic medicine and managed care. The participants agreed that there are indeed some common areas in which the two types of organizations can develop programs and interests that serve the missions of both. These include (1) a commitment to high-quality health care, objectively measured by outcomes; (2) issues of "customer service"; (3) certain areas of research (e.g., examining outcomes of medical interventions; measuring cost and cost-effectiveness; measuring quality of care); and (4) preventive medicine, an area in which both AHCs and MCOs are still relatively weak. On the other hand, large elements of AHCs' basic missions of education and research are not seen by MCOs as areas for developing a common agenda. Participants agreed that AHCs must do their best to improve and demonstrate the quality of their care, address the challenges of the market (i.e., take "customer service" seriously), address the issue of how many specialists and how many generalists should be trained, and define the cost of each of their missions. On the other hand, managed care must acknowledge that the missions of AHCs greatly benefit patients and society. Participants agreed that all approaches to AHC-MCO interfaces must be flexible and local, that common ground does exist, and that understanding can grow between these two kinds of organizations if acrimonious exchanges are avoided and serious efforts are made to work together for solutions.

The role of diet and exercise in the statin era.

Coronary atherosclerosis begins to develop in late adolescence and early adulthood. If intervention in coronary risk factors is delayed until middle-age, it is likely that a considerable number of patients will be lost to irreversible disease. Even with the dramatic cholesterol lowering that can be induced by statin drugs, coronary events can be reduced by only 25% to 40%, leaving most at-risk patients unprotected. Diet, exercise, and other nonpharmacological interventions have a role in the age of statins, not only to augment the effects of these drugs in high-risk patients, but also, by preventing atherogenesis in the first place, to reduce the number of at-risk patients.

Women, dyslipoproteinemia, and estrogens.

The most common cause of death in both men and women is coronary atherosclerosis, although atherosclerotic death in women occurs 5 to 10 years later than it does in men. Major risk factors predict coronary risk in both. Available evidence suggests that women benefit from cholesterol lowering just as men do. The role of exogenous estrogenic compounds in favorably affecting lipoprotein levels and promoting antiatherogenesis in both men and women is a promising area for future research.