Gating Orbital Memory with an Atomic Donor.

Orbital memory is defined by two stable valencies that can be electrically switched and read out. To explore the influence of an electric field on orbital memory, we studied the distance-dependent influence of an atomic Cu donor on the state favorability of an individual Co atom on black phosphorus. Using low temperature scanning tunneling microscopy and spectroscopy, we characterized the electronic properties of individual Cu donors, corroborating this behavior with ab initio calculations based on density functional theory. We studied the influence of an individual donor on the charging energy and stochastic behavior of an individual Co atom. We found a strong impact on the state favorability in the stochastic limit. These findings provide quantitative information about the influence of local electric fields on atomic orbital memory.

Stochastic Syncing in Sinusoidally Driven Atomic Orbital Memory.

Stochastically fluctuating multiwell systems are a promising route toward physical implementations of energy-based machine learning and neuromorphic hardware. One of the challenges is finding tunable material platforms that exhibit such multiwell behavior and understanding how complex dynamic input signals influence their stochastic response. One such platform is the recently discovered atomic Boltzmann machine, where each stochastic unit is represented by a binary orbital memory state of an individual atom. Here, we investigate the stochastic response of binary orbital memory states to sinusoidal input voltages. Using scanning tunneling microscopy, we investigated orbital memory derived from individual Fe and Co atoms on black phosphorus. We quantify the state residence times as a function of various input parameters such as frequency, amplitude, and offset voltage. The state residence times for both species, when driven by a sinusoidal signal, exhibit synchronization that can be quantitatively modeled by a Poisson process based on the switching rates in the absence of a sinusoidal signal. For individual Fe atoms, we also observe a frequency-dependent response of the state favorability, which can be tuned by the input parameters. In contrast to Fe, there is no significant frequency dependence in the state favorability for individual Co atoms. Based on the Poisson model, the difference in the response of the state favorability can be traced to the difference in the voltage-dependent switching rates of the two different species. This platform provides a tunable way to induce population changes in stochastic systems and provides a foundation toward understanding driven stochastic multiwell systems.

Equipping for risk: Lessons learnt from the UK shale-gas experience on assessing environmental risks for the future geoenergy use of the deep subsurface.

findings are presented from an investigation to improve understanding of the environmental risks associated with developing an unconventional-hydrocarbons industry in the UK. The EQUIPT4RISK project, funded by UK Research Councils, focused on investigations around Preston New Road (PNR), Fylde, Lancashire, and Kirby Misperton Site A (KMA), North Yorkshire, where operator licences to explore for shale gas by hydraulic fracturing (HF) were issued in 2016, although exploration only took place at PNR. EQUIPT4RISK considered atmospheric (greenhouse gases, air quality), water (groundwater quality) and solid-earth (seismicity) compartments to characterise and model local conditions and environmental responses to HF activities. Risk assessment was based on the source-pathway-receptor approach. Baseline monitoring of air around the two sites characterised the variability with meteorological conditions, and isotopic signatures were able to discriminate biogenic methane (cattle) from thermogenic (natural-gas) sources. Monitoring of a post-HF nitrogen-lift (well-cleaning) operation at PNR detected the release of atmospheric emissions of methane (4.2 ± 1.4 t CH4). Groundwater monitoring around KMA identified high baseline methane concentrations and detected ethane and propane at some locations. Dissolved methane was inferred from stable-isotopic evidence as overwhelmingly of biogenic origin. Groundwater-quality monitoring around PNR found no evidence of HF-induced impacts. Two approaches for modelling induced seismicity and associated seismic risk were developed using observations of seismicity and operational parameters from PNR in 2018 and 2019. Novel methodologies developed for monitoring include use of machine learning to identify fugitive atmospheric methane, Bayesian statistics to assess changes to groundwater quality, a seismicity forecasting model seeded by the HF-fluid injection rate and high-resolution monitoring of soil-gas methane. The project developed a risk-assessment framework, aligned with ISO 31000 risk-management principles, to assess the theoretical combined and cumulative environmental risks from operations over time. This demonstrated the spatial and temporal evolution of risk profiles: seismic and atmospheric impacts from the shale-gas operations are modelled to be localised and short-lived, while risk to groundwater quality is longer-term.

Extreme enhancement of superconductivity in epitaxial aluminum near the monolayer limit.

BCS theory has been widely successful at describing elemental bulk superconductors. Yet, as the length scales of such superconductors approach the atomic limit, dimensionality as well as the environment of the superconductor can lead to drastically different and unpredictable superconducting behavior. Here, we report a threefold enhancement of the superconducting critical temperature and gap size in ultrathin epitaxial Al films on Si(111), when approaching the 2D limit, based on high-resolution scanning tunneling microscopy/spectroscopy (STM/STS) measurements. Using spatially resolved spectroscopy, we characterize the vortex structure in the presence of a strong Zeeman field and find evidence of a paramagnetic Meissner effect originating from odd-frequency pairing contributions. These results illustrate two notable influences of reduced dimensionality on a BCS superconductor and present a platform to study BCS superconductivity in large magnetic fields.

Afterslip Moment Scaling and Variability From a Global Compilation of Estimates.

Aseismic afterslip is postseismic fault sliding that may significantly redistribute crustal stresses and drive aftershock sequences. Afterslip is typically modeled through geodetic observations of surface deformation on a case-by-case basis, thus questions of how and why the afterslip moment varies between earthquakes remain largely unaddressed. We compile 148 afterslip studies following 53 M w 6.0-9.1 earthquakes, and formally analyze a subset of 88 well-constrained kinematic models. Afterslip and coseismic moments scale near-linearly, with a median Spearman's rank correlation coefficient (CC) of 0.91 after bootstrapping (95% range: 0.89-0.93). We infer that afterslip area and average slip scale with coseismic moment as M o 2 / 3 and M o 1 / 3 , respectively. The ratio of afterslip to coseismic moment (M rel ) varies from <1% to >300% (interquartile range: 9%-32%). M rel weakly correlates with M o (CC: -0.21, attributed to a publication bias), rupture aspect ratio (CC: -0.31), and fault slip rate (CC: 0.26, treated as a proxy for fault maturity), indicating that these factors affect afterslip. M rel does not correlate with mainshock dip, rake, or depth. Given the power-law decay of afterslip, we expected studies that started earlier and spanned longer timescales to capture more afterslip, but M rel does not correlate with observation start time or duration. Because M rel estimates for a single earthquake can vary by an order of magnitude, we propose that modeling uncertainty currently presents a challenge for systematic afterslip analysis. Standardizing modeling practices may improve model comparability, and eventually allow for predictive afterslip models that account for mainshock and fault zone factors to be incorporated into aftershock hazard models.

On the Use of High-Resolution and Deep-Learning Seismic Catalogs for Short-Term Earthquake Forecasts: Potential Benefits and Current Limitations.

Enhanced earthquake catalogs provide detailed images of evolving seismic sequences. Currently, these data sets take some time to be released but will soon become available in real time. Here, we explore whether and how enhanced seismic catalogs feeding into established short-term earthquake forecasting protocols may result in higher predictive skill. We consider three enhanced catalogs for the 2016-2017 Central Italy sequence, featuring a bulk completeness lower by at least two magnitude units compared to the real-time catalog and an improved hypocentral resolution. We use them to inform a set of physical Coulomb Rate-and-State (CRS) and statistical Epidemic-Type Aftershock Sequence (ETAS) models to forecast the space-time occurrence of M3+ events during the first 6 months of the sequence. We track model performance using standard likelihood-based metrics and compare their skill against the best-performing CRS and ETAS models among those developed with the real-time catalog. We find that while the incorporation of the triggering contributions from new small magnitude detections of the enhanced catalogs is beneficial for both types of forecasts, these models do not significantly outperform their respective near real-time benchmarks. To explore the reasons behind this result, we perform targeted sensitivity tests that show how (a) the typical spatial discretizations of forecast experiments ( ≥ 2 km) hamper the ability of models to capture highly localized secondary triggering patterns and (b) differences in earthquake parameters (i.e., magnitude and hypocenters) reported in different catalogs can affect forecast evaluation. These findings will contribute toward improving forecast model design and evaluation strategies for next-generation seismic catalogs.

An atomic Boltzmann machine capable of self-adaption.

The quest to implement machine learning algorithms in hardware has focused on combining various materials, each mimicking a computational primitive, to create device functionality. Ultimately, these piecewise approaches limit functionality and efficiency, while complicating scaling and on-chip learning, necessitating new approaches linking physical phenomena to machine learning models. Here, we create an atomic spin system that emulates a Boltzmann machine directly in the orbital dynamics of one well-defined material system. Utilizing the concept of orbital memory based on individual cobalt atoms on black phosphorus, we fabricate the prerequisite tuneable multi-well energy landscape by gating patterned atomic ensembles using scanning tunnelling microscopy. Exploiting the anisotropic behaviour of black phosphorus, we realize plasticity with multi-valued and interlinking synapses that lead to tuneable probability distributions. Furthermore, we observe an autonomous reorganization of the synaptic weights in response to external electrical stimuli, which evolves at a different time scale compared to neural dynamics. This self-adaptive architecture paves the way for autonomous learning directly in atomic-scale machine learning hardware.

A scanning tunneling microscope capable of electron spin resonance and pump-probe spectroscopy at mK temperature and in vector magnetic field.

In the last decade, detecting spin dynamics at the atomic scale has been enabled by combining techniques such as electron spin resonance (ESR) or pump-probe spectroscopy with scanning tunneling microscopy (STM). Here, we demonstrate an ultra-high vacuum STM operational at milliKelvin (mK) temperatures and in a vector magnetic field capable of both ESR and pump-probe spectroscopy. By implementing GHz compatible cabling, we achieve appreciable RF amplitudes at the junction while maintaining the mK base temperature and high energy resolution. We demonstrate the successful operation of our setup by utilizing two experimental ESR modes (frequency sweep and magnetic field sweep) on an individual TiH molecule on MgO/Ag(100) and extract the effective g-factor. We trace the ESR transitions down to MHz into an unprecedented low frequency band enabled by the mK base temperature. We also implement an all-electrical pump-probe scheme based on waveform sequencing suited for studying dynamics down to the nanoseconds range. We benchmark our system by detecting the spin relaxation time T1 of individual Fe atoms on MgO/Ag(100) and note a field strength and orientation dependent relaxation time.

[Invasive diagnostic procedures for insulinomas of the pancreas]. / Invasive Diagnostik bei Insulinomen des Pankreas.

Insulinomas are the most common cause for hypoglycemia with endogenous hyperinsulinism. Insulinomas are the most frequent endocrine tumor of the pancreas and 10% occur as multiple tumors (e.g. multiple endocrine neoplasia type I) or in rare cases as islet cell hyperplasia. A further 10-15% of insulinomas are malignant. Non-invasive imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and somatoreceptor scintigraphy (SRN) show a lower sensitivity for detection and localization of tumors, because in many cases insulinomas are smaller than 2 cm in size. Invasive pre-operative diagnostic procedures, such as transhepatic peripancreatic venous blood sampling (TPVB) and the intra-arterial calcium stimulation test (ASVS) are much more time-intensive compared to CT, MRI and US with an examination time of 2-3 h but achieve a more exact pre-operative detection and localization with sensitivities mostly greater than 95% and are therefore the diagnostic methods of choice.

An orbitally derived single-atom magnetic memory.

A magnetic atom epitomizes the scaling limit for magnetic information storage. Individual atomic spins have recently exhibited magnetic remanence, a requirement for magnetic memory. However, such memory has been only realized on thin insulating surfaces, removing potential tunability via electronic gating or exchange-driven magnetic coupling. Here, we show a previously unobserved mechanism for single-atom magnetic storage based on bistability in the orbital population, or so-called valency, of an individual Co atom on semiconducting black phosphorus (BP). Ab initio calculations reveal that distance-dependent screening from the BP surface stabilizes the two distinct valencies, each with a unique orbital population, total magnetic moment, and spatial charge density. Excellent correspondence between the measured and predicted charge densities reveal that such orbital configurations can be accessed and manipulated without a spin-sensitive readout mechanism. This orbital memory derives stability from the energetic barrier to atomic relaxation, demonstrating the potential for high-temperature single-atom information storage.

[Liver transplantation in paediatric patients in the Netherlands; evolution over the past two decades]. / Levertransplantaties bij kinderen in Nederland.

OBJECTIVE: To evaluate the results of the national paediatric liver transplantation programme in the University Medical Centre (UMC) Groningen in the Netherlands during the past two decades. DESIGN: Retrospective cohort study. METHOD: We analysed data from paediatric patients who underwent liver transplantation at UMC Groningen in the period 1995-2016. We compared outcomes from children who had undergone a liver transplantation in the period 1995-2005 (cohort A; n = 126) and in the period 2006-2016 (cohort B; n = 169). We performed a subanalysis in cohort B between liver transplantations with deceased donor livers (n = 132) and living donor liver transplantations (LDLT; n = 37). RESULTS: In cohort A, almost all livers came from deceased donors (99%), whereas in cohort B, 37 LDLTs (22%) were performed. The median age of recipients was significantly higher in cohort A (4.4 vs. 2.5 years; p = 0.015). Postoperative complications were comparable for both cohorts. Re-transplantations within a year after transplantation were more often performed in cohort A than in cohort B (25% vs. 12%; p = 0.004). Following LDLT, there was 2 times (5.4%) an indication for re-transplantation. In cohort B the 5-year survival rate was better than in cohort A (83 vs. 71%; p = 0.014). In cohort B, 5-year survival was higher after LDLT than after transplantation with a deceased donor liver (95 vs. 81%; p = 0.025). CONCLUSION: Outcomes after paediatric liver transplantation in the Netherlands have further improved during the past two decades. With an actuarial 5-year survival of 83% in the most recent cohort, and as high as 95% following LDLT, we can say that the UMC Groningen has a successful national paediatric liver transplant programme.

Screening, early identification, and office-based intervention with children and youth living in substance-abusing families.

All health care professionals with clinical responsibility for the care of children and adolescents must be able to recognize, as early as possible, associated health problems or concerns in children of substance-abusing parents, and to be able to assist these children and families in seeking treatment and promoting health. Health care providers can have a tremendous influence on families of substance-abusing parents because of their understanding of family dynamics and their close long-standing relationship with the family. Information about family alcohol and other drug use should be obtained as part of routine history-taking and when there are indications of family dysfunction, child behavior or emotional problems, school difficulties, and recurring episodes of apparent accidental trauma, and in the setting of recurrent or multiple vague somatic complaints by the child or adolescent. In many instances, family problems with alcohol or drug use are not blatant; rather, their identification requires a deliberate and skilled screening effort. Combining the principles of anticipatory guidance, screening, and early identification, with the acknowledgment that families should be included in the process, leads to a clear conclusion that screening for children affected by parental substance abuse must occur at all ages across infancy, childhood, and adolescence. Health care providers need to be trained in the identification and management of children and youth exposed to parental addiction. Such training must begin during undergraduate education in the health professions and be reinforced by role-modeling among health professions faculty as well as practicing providers.

Early identification, screening, and brief intervention for adolescent alcohol use.

The high prevalence of alcohol and other drug use by adolescents poses a significant threat to the wellness of youth. Whereas there has been a significant decrease in the reported prevalence of use for most illicit drugs, there has been relatively little change in the reported use of alcohol and tobacco, the two most common drugs of abuse. As such, alcohol remains the drug of choice for most adolescents. In 1993, 67% of eighth graders had tried alcohol in their lifetime, as had 81% of 10th graders and 87% of high school seniors. More than a quarter of eighth graders (26%) had used alcohol in the past month, as had 42% of 10th graders and 51% of high school seniors. Most disturbing is that, in all three grade levels, among those who had used alcohol in the past 30 days, half or more had had five or more drinks in a row at least once (13.5%, 23%, and 28%, respectively). Although only 1% of adolescents consider themselves to have a drinking problem, 23% have often driven after excessive drinking, 17% report problems in peer relationships because of drinking, and 10% have been criticized by a close friend for drinking.

Longitudinal evaluation of a screening measure for problem drinking among female college freshmen.

OBJECTIVE: A previous study suggested that combining the CAGE (cutting down of drinking, feeling annoyed by criticisms of drinking, feeling guilty about something that happened because of drinking, having an eye-opener) questionnaire with the Perceived-Benefit-of-Drinking Scale, an adolescent's use of tobacco, the age at which an adolescent first started drinking, and an adolescent's best friend's drinking pattern is a useful composite screening measure for problem drinking among adolescents. The present study was undertaken to evaluate prospectively this composite screening measure as a predictor of subsequent problem drinking among college women during their freshman year. DESIGN: Cross-sectional. SETTING: Private university student health service. PARTICIPANTS: A random sample of 248 college freshman women entered a longitudinal study of alcohol use at the beginning of their freshman year. One hundred twenty (48%) completed follow-up measures of alcohol use at the end of the year. Respondents were 90% white, with a mean age of 17.9 years (SD = 0.5 years). MAIN OUTCOME MEASURES: An index of the quantity and frequency of alcohol use and a composite measure of specific alcohol-related problems. RESULTS: The CAGE questionnaire score, the Perceived-Benefit-of-Drinking Scale score, the student's tobacco use, the student's best friend's drinking pattern, and the age at which the student first started drinking as reported at the beginning of the year together explained 38% of the variance in subsequent drinking habits and 26% of the variance in alcohol-related problems reported during the freshman year. Use of the composite screening measure significantly increased sensitivity and specificity beyond that obtained with the CAGE questionnaire or the Perceived-Benefit-of-Drinking Scale alone for problem drinking. CONCLUSIONS: The CAGE questions, the Perceived-Benefit-of-Drinking Scale, the student's tobacco use, the student's best friend's drinking pattern, and the age at which the student first started drinking may together constitute a clinically useful screening measure for subsequent problem drinking among female college freshmen.

Relation of alcohol expectancies to changes in problem drinking among college students.

OBJECTIVE: To evaluate the relation between alcohol expectancies and problem drinking during 3 years of college. DESIGN: Cohort with 3-year follow-up. SETTING: Private university campus. PARTICIPANTS: A random sample of 260 students entered a longitudinal study of alcohol use at the beginning of their freshman year. One hundred eighty-four students completed follow-up measures at the end of their junior year. Respondents were 90% white, with a mean (+/-SD) age of 17.9 +/- 0.5 years. INTERVENTIONS: None. MAIN OUTCOME MEASURES: A standardized measure of expectations and subjective evaluations of outcomes associated with drinking, quantity and frequency of alcohol use, and a composite measure of alcohol-related problems. RESULTS: Students were divided into nondrinking, low-risk, and high-risk groups for problem drinking. A repeated-measures multivariate analysis of variance indicated significant interaction effects for risk group by expectancy scale (P < .009) and for expectancy scale by time (P < .001). The three risk groups differed significantly from each other on positive outcome expectations at entry into college and positive expectations and negative outcome evaluations at the end of the junior year. Students who became problem drinkers during college had significantly higher positive outcome expectation scores at both times and developed less concern for negative outcomes by the end of their junior year. The few initial problem drinkers who moderated their drinking during college demonstrated an increased concern for negative outcomes by their junior year. CONCLUSIONS: Alcohol expectancies are associated with differing patterns of alcohol use and are longitudinally related to subsequent changes in alcohol use and problem drinking.

Antithrombin III deficiency, deep venous thrombosis, and oral contraceptive use.

PIP: Oral contraceptive use is a risk factor for the development of deep venous thromboses in adolescents. Most patients with venous thromboses have no well-defined disorder of hemostasis. Identifying such abnormalities in some patients, however, will allow the best decisions to be made concerning contraceptive practices, the treatment of acute thromboses, and long-term prophylaxis. For example, studies have established a relationship between oral contraceptive use and changes in antithrombin III. A case is presented which highlights the multifaceted nature of venous thromboses and the need for clinicians to be aware of potential hypercoagulable states and their implications for patient care. A 16-year-old Black female had a five-day history of rapidly progressive left leg swelling and pain. Five weeks earlier she was diagnosed with dysfunctional uterine bleeding and placed upon a triphasic oral contraceptive. This patient had multiple risks for thrombosis including obesity, prolonged periods of bed rest, oral contraceptive use, and possibly hypercoagulability related to markedly decreased antithrombin III levels. The patient was initially felt to be at high risk for a congenital antithrombin III deficiency because of her profoundly low plasma level and thus treated with antithrombin III concentrates. Based on the subsequent normalization of her antithrombin III levels, however, it appears that her acquired deficiency resulted from either accelerated utilization associated with an extensive thrombus or oral contraceptive use or the combination of both. Decreases in antithrombin III of this magnitude have not been previously reported in association with either oral contraceptives or extensive thromboses. The clinical importance of acquired antithrombin III deficiency for an increased risk of venous thromboembolism remains uncertain.^ieng

Urinary leukocyte esterase screening for asymptomatic sexually transmitted disease in adolescent males.

The objective of this study was to evaluate the effectiveness of urinary leukocyte esterase on random urine specimens as a screening test for chlamydial and gonococcal urethral infections in asymptomatic males. Random urine specimens were obtained on 106 consecutive asymptomatic adolescent males during intake physical examination at a residential vocational training program. Results of urinary leukocyte esterase were compared to those of urethral cultures for Chlamydia trachomatis and Neisseria gonorrhoeae. Five subjects had positive chlamydia cultures, three subjects had positive gonococcal cultures, and one patient had positive cultures for both organisms. Sixteen subjects had leukocyte esterase tests reported as "trace" or greater. When compare to positive culture results for either Chlamydia or gonorrhea, urinary leukocyte esterase activity had a sensitivity of 78%, specificity of 91%, and positive predictive value of 44%. A random urine specimen for urinary leukocyte esterase activity is a cost-effective screening method for chlamydial and gonococcal urethral infections in asymptomatic adolescent males.

Problem drinking among college freshmen.

Entering college freshmen (n = 308) completed a questionnaire which assessed drinking behaviors and identified students at risk for problem drinking as defined by the CAGE (focuses on Cutting down on drinking, Annoyance by criticism by others about drinking, Guilty feelings about drinking, and the use of an Eye opener) questionnaire and Perceived-Benefit-of-Drinking Scale (PBDS). Students were 50% male with a mean age of 17.9 years. In the past month, 17% had drunk on 10 or more occasions, and 18% had binged on 6 or more occasions. CAGE scores of 2 or greater were obtained by 21% and PBDS scores of 3 or greater by 29%, reflecting high risk for problem drinking. High-risk CAGE and PBDS scores were associated with frequent drinking and binging. Student reports of parental problem drinking were not associated with high risk for problem drinking. Intent to join a fraternity or sorority (the Greek system) was associated with frequent drinking, binging, and high-risk CAGE and PBDS scores. Approaches to screening for problem drinking which emphasize attitudes and beliefs may be useful. The Greek system appears to be attractive to high-risk students and should be a focus of prevention programming.

Alcohol expectancies, problem drinking, and adverse health consequences.

This study evaluated a measure of positive and negative expected effects of alcohol and their subjective evaluation in the identification of college freshmen at high risk for problem drinking and associated morbidities. It was hypothesized that greater expectations of positive outcomes and fewer negative evaluations of negative outcomes would be associated with reports of heavier drinking and more alcohol-related health problems. College freshmen (n = 328) completed a standardized measure of expectations and subjective evaluations of positive and negative outcomes associated with drinking, and a questionnaire assessing drinking patterns and common alcohol-related health problems. Fifty-two percent of students were male and the mean age was 17.9 years (SD = 0.5). Students' expectations of positive outcomes and their subjective evaluations of both positive and negative outcomes from drinking were significantly correlated with drinking and alcohol-related health problems indices (p < 0.001). Gender, expectation of positive outcomes, and evaluation of negative outcomes explained 29% of the variance in drinking and 15% of the variance in alcohol-related health problems indices. Heavier-drinking students and those reporting more health problems expected more positive effects on their sociability and sexuality (p < 0.03) and were less concerned about cognitive and behavioral impairment as a result of drinking (p < 0.001). Students with more health problems were less concerned that drinking would lead to risk-taking or aggressive behavior (p < 0.003). Positive and negative outcome expectancies and their subjective evaluations accounted for a significant portion of the variability in drinking and alcohol-related health problems.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical needs of performing arts students.

A questionnaire was administered to 71 college students enrolled in dance, drama, and musical theater programs to assess health care problems, injuries, risk-taking behaviors, and sources of care. Many desired help with depression, fatigue, and chronic bone or joint pain, although 37% identified no regular physician. Thirty-nine students reported 87 injuries involving the back, foot, ankle, and knee; 12% sustained injuries at least monthly; and 72% of injuries occurred in class. The incidence of eating disorders appears to be low, as assessed by indirect measures such as body weight, oligomenorrhea, diet pill or laxative use, and scores on a body image index. The 30-day prevalence of tobacco use was 26%; marijuana, 11%; and alcohol, 71%. This survey suggests that performing arts students have important unmet health care needs.