Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

The Pluto system: Initial results from its exploration by New Horizons.

The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

Attainment of Canadian and European guidelines' lipid targets with atorvastatin plus ezetimibe vs. doubling the dose of atorvastatin.

BACKGROUND: Canadian and European treatment guidelines identify low-density lipoprotein cholesterol (LDL-C) as a primary treatment target for hypercholesterolaemia. OBJECTIVES: This post hoc analysis compared ezetimibe 10 mg (ezetimibe) added to atorvastatin vs. doubling the atorvastatin dose on achievement of the 2009 Canadian Cardiovascular Society (CCS) and the 2007 Joint European Prevention Guidelines primary and optional secondary lipid targets and high-sensitivity C-reactive protein (hs-CRP) levels. METHODS: After stabilisation on atorvastatin, hypercholesterolaemic patients at moderately high risk (MHR) for coronary heart disease (CHD) not at LDL-C < 2.6 mmol/l were randomised to atorvastatin 20 mg vs. doubling their atorvastatin dose to 40 mg; and patients at high risk (HR) for CHD not at LDL-C < 1.8 mmol/l were randomised to atorvastatin 40 mg plus ezetimibe vs. doubling their atorvastatin dose to 80 mg for 6 weeks. RESULTS: When treated with atorvastatin plus ezetimibe, MHR and HR patients had greater attainment of LDL-C, most lipids and lipoproteins and/or hs-CRP targets compared with doubling their atorvastatin dose. More MHR and HR patients achieved dual targets of LDL-C and: Apolipoprotein (Apo) B, total cholesterol (total-C), total-C/high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides, Apo B/Apo A-I or hs-CRP with ezetimibe + atorvastatin treatment compared with doubling their atorvastatin dose. CONCLUSIONS: These results demonstrated greater achievement of single/dual treatment targets as set by Canadian and European treatment guidelines with ezetimibe added to atorvastatin 20 mg or 40 mg compared with doubling the atorvastatin dose to 40 mg or 80 mg in MHR and HR patients, respectively.

Ezetimibe added to atorvastatin compared with doubling the atorvastatin dose in patients at high risk for coronary heart disease with diabetes mellitus, metabolic syndrome or neither.

AIM: Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) are both associated with increased risk for atherosclerotic coronary heart disease (CHD). Thus, it is useful to know the relative efficacy of lipid-altering drugs in these patient populations. METHODS: A double-blind, parallel group trial of adult patients with hypercholesterolaemia at high-CHD risk receiving atorvastatin 40 mg/day compared atorvastatin 40 mg plus ezetimibe 10 mg (ezetimibe) vs. doubling atorvastatin to 80 mg. This post hoc analysis reports lipid efficacy results in patients grouped by diagnosis of T2DM, MetS without T2DM or neither. Per cent change from baseline at week 6 was assessed for LDL-C, total cholesterol, HDL-C , non-HDL-C , Apo A-I, Apo B and triglycerides. Safety was monitored through clinical and laboratory adverse events (AEs). RESULTS: Compared with doubling atorvastatin, atorvastatin plus ezetimibe resulted in greater reductions in LDL-C, triglycerides, Apo B, non-HDL-C, total cholesterol and lipid ratios in the T2DM, MetS and neither groups. Treatment effects were of similar magnitude across patient groups with both treatments, except triglycerides, which were slightly greater in the T2DM and MetS groups vs. neither group. Changes in HDL-C , Apo A-I and high sensitivity C-reactive protein (hs-CRP) were comparable for both treatments in all three groups. Safety and tolerability profiles were generally similar between treatments and across patient groups, as were the incidence of liver and muscle AEs. CONCLUSIONS: Compared with doubling atorvastatin to 80 mg, addition of ezetimibe to atorvastatin 40 mg produced greater improvements in multiple lipid parameters in high-CHD risk patients with T2DM, MetS or neither, consistent with the significantly greater changes observed in the full study cohort (clinical trial # NCT00276484).

Io's atmospheric response to eclipse: UV aurorae observations.

The New Horizons (NH) spacecraft observed Io's aurora in eclipse on four occasions during spring 2007. NH Alice ultraviolet spectroscopy and concurrent Hubble Space Telescope ultraviolet imaging in eclipse investigate the relative contribution of volcanoes to Io's atmosphere and its interaction with Jupiter's magnetosphere. Auroral brightness and morphology variations after eclipse ingress and egress reveal changes in the relative contribution of sublimation and volcanic sources to the atmosphere. Brightnesses viewed at different geometries are best explained by a dramatic difference between the dayside and nightside atmospheric density. Far-ultraviolet aurora morphology reveals the influence of plumes on Io's electrodynamic interaction with Jupiter's magnetosphere. Comparisons to detailed simulations of Io's aurora indicate that volcanoes supply 1 to 3% of the dayside atmosphere.

Population structure, genetic diversity, and clone formation in Quercus chrysolepis (Fagaceae).

Stands of canyon live oak (Quercus chrysolepis, Fagaceae) are maintained for fuelwood, fire management, recreation, and as habitat for wildlife. Information about the link between the oak's reproductive ecology and its extent of genetic diversity is important in developing land management policies that will maintain the long-term viability of populations. Basal sprouting is the primary means of reproduction following fire or cutting, and stands frequently include groups of visibly connected trees in a clustered distribution that suggests cloning. We determined the extent to which clusters of trees were clonal and defined the spatial pattern and diversity of genotypes for six populations across nearly the entire east-west extent of the San Bernardino Mountains in southern California. We mapped over 100 trees at each of five sites and genotyped each tree for allozymes at seven polymorphic loci. We identified clones using these multilocus genotypes and detected an average of 34.4 ± 7.3 (SD) clones per site, most of which had unique genotypes. In general, clustered trees belong to single clones and most clones consist of few trees (mean = 3.4 ± 0.6 trees per clone). However, clone size increased significantly with increased individual heterozygosity, suggesting that selection may favor highly heterozygous clones. Clonal diversity and evenness were high relative to reports for most other clonal species; an average of 97% of clones had distinct genotypes, and Simpson's index of diversity averaged 0.95 ± 0.02. Population genetic analyses of 319 clones from six sites revealed high genetic diversity within sites (mean HS = 0.443). Only a small proportion of the total genetic diversity was explained by variation among sites (mean GST = 0.018), which is consistent with high gene flow among sites (Nm = 9.5). We found no significant substructure among plots within sites, and fixation indices within sites were generally small, suggesting that either little inbreeding occurs, and/or few inbred progeny survive. However, spatial autocorrelation analysis of clones indicated fine-scale genetic structure at distances under 4 m, possibly due to limited seed dispersal. Our data suggest that guidelines for seed collection of canyon live oak for use in restoration can be specified in a manner similar to that recommended for conifer species within the region studied.

Resident physician substance use, by specialty.

OBJECTIVE: This study compares substance use by medical specialty among resident physicians. METHOD: The authors estimated the prevalence of substance use of 11 medical specialties from a national sample of 1,754 U.S. resident physicians. RESULTS: Emergency medicine and psychiatry residents showed higher rates of substance use than residents in other specialties. Emergency medicine residents reported more current use of cocaine and marijuana, and psychiatry residents reported more current use of benzodiazepines and marijuana. Contrary to recent concerns, anesthesiology residents did not have high rates of substance use. Family/general practice, internal medicine, and obstetrics/gynecology were not among the higher or lower use groups for most substances. Surgeons had lower rates of substance use except for alcohol. Pediatric and pathology residents were least likely to be substance users. CONCLUSIONS: The authors' previous research indicates that residents overall have lower rates of substance use than their age peers in society. Yet resident substance use patterns do differ by specialty. Residents in some specialties are more likely to use specific classes of drugs, to use a greater number of drug classes, and to be daily users of alcohol or cigarettes.

Patterns of substance use in the medical profession.

National drug use surveys of medical students and resident physicians in 1987 found that medical school was not a time when students began to use drugs, nor was it a time when they engaged in heavy use. Medical students and resident physicians reported lower rates of illicit drug use than their age and gender counterparts. Although males generally were more likely to use substances than females, young male and female physicians resembled one another in their current rates of substance use more than they resembled their gender counterparts in society.

Relations among stressors, strains, and substance use among resident physicians.

This study examined the relationship between work-related stress and substance use among resident physicians in the United States. Unlike previous studies of physician stress, this study distinguished between "stressors" (stressful job conditions) and "strains" (reactions to the work environment) and correlated each of these with substance use. Results indicated that relations among stressors, strains, and substance use were not strong. Strains, however, were more strongly related to substance use than stressors. Additionally, benzodiazepines were more strongly related to strains than other substances, suggesting that they may be used for self-treatment. Other implications of these findings and future research needs are discussed.

Behavioral consequences of job-related stress among resident physicians: the mediating role of psychological strain.

This study examined the correlations among stressors, psychological strain, and behavioral reactions in a national sample of 1785 resident physicians, 27 to 33 years old. Consistent with previous studies of resident physicians, analysis showed that those experiencing high job-related stressors experienced high psychological strain in both their personal and professional lives. Stressors were also correlated with behavioral reactions. Hierarchical regression suggested that psychological strain mediated the relations between two of the stressors and behavioral reactions to some extent. This was consistent with recent research suggesting that psychological reactions may mediate the relations between stressors and outcomes. Further research on both medical residency and the stressing process was suggested.

Outcomes of the first Family Practice Chief Resident Leadership Conference.

In June 1989 the first Family Practice Chief Resident Leadership Conference was presented to 27 Texas second-year residents who had been selected to serve as chief residents during their third year. The objectives of the conference were to assist these emerging leaders to develop better stress management and leadership skills and to strengthen their ties with the Texas Academy of Family Physicians. The conference featured two major workshops on stress management and leadership skills, and included plenary speeches and large and small group discussions. This article reports the outcomes of the conference as measured by the evaluation instrument completed by participants. Analysis of the results indicated that the conference had a positive effect on the residents.

Resident physician substance use in the United States.

A national survey was conducted to determine patterns of drug use among 3000 American resident physicians. Sixty percent (1785) of the residents surveyed responded. This report evaluates the prevalence of drug use among the respondents, when they initiated drug use, and their reasons for current use. Substance use rates are compared with other studies of resident physicians and with a sample of their nonphysician age peers surveyed the same year. Heavy substance use patterns were not observed among resident physicians. They had significantly lower rates of use for most psychoactive substances than their peers in the general population but did report higher rates of past-month use of alcohol and benzodiazepines. A sizable minority began using benzodiazepines and prescription opiates during their residency years-the stage in physicians' training when they first receive prescribing privileges. Current users of benzodiazepines and opiates used these drugs primarily for self-treatment rather than recreation. These two substances are often associated with impairment at later stages in the physician's career.

Substance use among senior medical students. A survey of 23 medical schools.

Senior students at 23 regionally distributed medical schools received an anonymous questionnaire designed to examine current and prior use of tobacco, alcohol, and nine other drugs. The overall response rate was 67% (N = 2046). Substance use prevalence rates during the 30 days preceding the survey included alcohol, 87.5%; marijuana, 10.0%; cigarettes, 10.0%; cocaine, 2.8%; tranquilizers, 2.3%; opiates other than heroin, 1.1%; psychedelics other than LSD (lysergic acid diethylamide), 0.6%; amphetamines, 0.3%; barbiturates, 0.2%; LSD, 0.1%; and heroin, 0.0%. Compared with national, age-related comparison groups, senior medical students reported less use of all substances during the past 30 days and the past 12 months, except for alcohol, tranquilizers, and psychedelics other than LSD. Substantial new drug use after entry into medical school was reported only for tranquilizers. Seven students (0.2%) admitted to current dependence on a substance other than tobacco, four of these implicating marijuana. Thirty-three students (1.6%) believed that they currently needed help for substance abuse. Only 25.7% were aware of any policy on substance abuse at their own school.

Cocaine use by senior medical students.

The authors studied 589 senior medical students' attitudes about and use of cocaine. Reported use was 36% in the students' lifetimes, 17% in the past year, and 6% in the past month. Overall, these rates were lower than those of an age-matched cohort.

Substance use by fourth-year students at 13 U.S. medical schools.

Fourth-year medical students at 13 medical schools in different regions of the United States received an anonymous questionnaire designed to examine their current and prior use of 11 substances and their attitudes toward substance use among physicians. Of 1,427 questionnaires distributed, 41 percent were returned. The questionnaire and distribution method were derived from an ongoing survey on drug use in order to permit comparison of the medical students with a national sample of age- and sex-matched cohorts. The rates of substance use during the 30 days preceding receipt of the questionnaire were: alcohol, 87.8 percent; marijuana, 17.3 percent; cigarettes, 9.0 percent; cocaine, 5.6 percent; heroin, 0.0 percent; other opiates, 0.9 percent; LSD, 0.2 percent; other psychedelics, 0.5 percent; barbiturates, 0.5 percent; tranquilizers, 2.2 percent; and amphetamines, 1.2 percent. Compared with their age and sex cohorts nationally, the medical students reported less use of marijuana, cocaine, cigarettes, LSD, barbiturates, and amphetamines. However, their use of other opiates was approximately the same and their use of tranquilizers and alcohol was slightly higher than that of the other cohorts. Data on their sources of knowledge about drug abuse indicate the need for greater attention to this issue in the medical curriculum.

Substance use and the resident physician: a national study.

A national study of substance use and abuse among resident physicians indicates that except for tranquilizers and barbiturates most illicit use of drugs began prior to medical school and residency. Relatively few residents were aware of substance abuse policies or educational programs in their institutions.

Substance use and abuse among senior medical students in 23 medical schools.

The current study represents the first large-scale study of substance use and abuse among 2,046 senior medical students at 23 nationally distributed medical schools. With the exception of alcohol and tranquilizers, medical students use less of all such substances than do age-related cohorts from the general population.