Pickup position and plucking point estimation on an electric guitar via autocorrelation.

This paper proposes a technique that estimates the locations along the string of the plucking event and the magnetic pickup of an electric guitar based on the autocorrelation of the spectral peaks. To improve accuracy, a method is introduced to flatten the spectrum before applying the autocorrelation function to the spectral peaks. The minimum mean squared error between the autocorrelation of the observed data and the electric guitar model is found in order to estimate the model parameters. The accuracy of the algorithm is tested on various plucking positions on all open strings for each pickup configuration. The accuracy of the proposed method for various plucking dynamics and fret positions is also evaluated. The method yields accurate results: the average absolute errors of the pickup position and plucking point estimates for single pickups are 3.53 and 5.11 mm, respectively, and for mixed pickups are 8.47 and 9.95 mm, respectively. The model can reliably distinguish which pickup configuration is selected using the pickup position estimates. Moreover, the method is robust to changes in plucking dynamics and fret positions.

Changes in Autonomic Nervous System Activity are Associated with Changes in Sexual Function in Women with a History of Childhood Sexual Abuse.

INTRODUCTION: Women with histories of childhood sexual abuse (CSA) have higher rates of sexual difficulties, as well as high sympathetic nervous system response to sexual stimuli. AIM: The study aims to examine whether treatment-related changes in autonomic balance, as indexed by heart rate variability (HRV), were associated with changes in sexual arousal and orgasm function. METHODS: In study 1, we measured HRV while writing a sexual essay in 42 healthy, sexually functional women without any history of sexual trauma. These data, along with demographics, were used to develop HRV norms equations. In study 2, 136 women with a history of CSA were randomized to one of three active expressive writing treatments that focused on their trauma, sexuality, or daily life (control condition). We recorded HRV while writing a sexual essay at pretreatment, posttreatment, and 2-week, and 1- and 6-month follow-ups; we also calculated the expected HRV for each participant based on the norms equations from study 1. MAIN OUTCOME MEASURES: The main outcome measures used were HRV, Female Sexual Function Index, Sexual Satisfaction Scale--Women. RESULTS: The difference between expected and observed HRV decreased over time, indicating that, posttreatment, CSA survivors displayed HRV closer to the expected HRV of a demographics-matched woman with no history of sexual trauma. Also, over time, participants whose HRV became less dysregulated showed the biggest gains in sexual arousal and orgasm function. These effects were consistent across condition. CONCLUSIONS: Treatments that reduce autonomic imbalance may improve sexual well-being among CSA populations.

Military, demographic, and psychosocial predictors of military retention in enlisted army soldiers 12 months after deployment to Iraq.

OBJECTIVE: To examine military, demographic, and psychosocial predictors of military retention following operational deployment. METHODS: Military status 12 months following return from Iraq deployment was assessed via service records in 740 regular active duty Army Soldiers. Potential predictors of military retention were derived from prospectively administered in-person interviews and questionnaires conducted within 3 months following return from Iraq. RESULTS: At 12 months following return from deployment, 18.1% (n = 134) of the sample had separated from military service. Cox proportional hazards analyses, adjusting for demographic, military, and psychosocial predictors, identified several factors that were independently associated with military attrition: less than (vs. equal to or more than) 6 years military experience (hazards ratio [HR], 3.98; 95% CI, 2.12-7.45); unmarried (vs. married) status (HR, 1.51; 95% CI, 1.06-2.16); and lower (vs. higher) levels of self-reported unit support during deployment (HR, 2.22; 95% CI, 1.42-3.47). CONCLUSIONS: Service members early in their career may be especially prone to military attrition. With regard to military retention, our findings suggest that it may be particularly important to develop initiatives that target organizational cohesion and support.

Association between exercise and posttraumatic stress symptoms among trauma-exposed adults.

The present investigation examined associations between intensities of exercise involvement and posttraumatic stress (PTS) symptom cluster severity (reexperiencing, avoidance/numbing, and hyperarousal). The sample was comprised of 108 adults (54.6% women; M age = 23.9, SD = 10.22, range = 18-62), who endorsed exposure to a Diagnostic and Statistical Manual of Mental Disorders (Fourth edition, Text Revision) posttraumatic stress disorder Criterion A traumatic life event but did not meet criteria for any current Axis I psychopathology. After controlling for gender and lifetime number of trauma exposure types experienced, results indicated that vigorous-intensity exercise, but not light- or moderate-intensity exercise, was significantly inversely associated with hyperarousal symptom cluster severity. This study adds to the scarce, yet growing, body of exercise-PTS literature-by illuminating the inverse associations of vigorous-intensity exercise, specifically, and PTS hyperarousal symptom severity among trauma-exposed individuals.

Nucleolar integrity is required for the maintenance of long-term synaptic plasticity.

Long-term memory (LTM) formation requires new protein synthesis and new gene expression. Based on our work in Aplysia, we hypothesized that the rRNA genes, stimulation-dependent targets of the enzyme Poly(ADP-ribose) polymerase-1 (PARP-1), are primary effectors of the activity-dependent changes in synaptic function that maintain synaptic plasticity and memory. Using electrophysiology, immunohistochemistry, pharmacology and molecular biology techniques, we show here, for the first time, that the maintenance of forskolin-induced late-phase long-term potentiation (L-LTP) in mouse hippocampal slices requires nucleolar integrity and the expression of new rRNAs. The activity-dependent upregulation of rRNA, as well as L-LTP expression, are poly(ADP-ribosyl)ation (PAR) dependent and accompanied by an increase in nuclear PARP-1 and Poly(ADP) ribose molecules (pADPr) after forskolin stimulation. The upregulation of PARP-1 and pADPr is regulated by Protein kinase A (PKA) and extracellular signal-regulated kinase (ERK)--two kinases strongly associated with long-term plasticity and learning and memory. Selective inhibition of RNA Polymerase I (Pol I), responsible for the synthesis of precursor rRNA, results in the segmentation of nucleoli, the exclusion of PARP-1 from functional nucleolar compartments and disrupted L-LTP maintenance. Taken as a whole, these results suggest that new rRNAs (28S, 18S, and 5.8S ribosomal components)--hence, new ribosomes and nucleoli integrity--are required for the maintenance of long-term synaptic plasticity. This provides a mechanistic link between stimulation-dependent gene expression and the new protein synthesis known to be required for memory consolidation.

Associations among smoking, anhedonia, and reward learning in depression.

Depression and cigarette smoking co-occur at high rates. However, the etiological mechanisms that contribute to this relationship remain unclear. Anhedonia and associated impairments in reward learning are key features of depression, which also have been linked to the onset and maintenance of cigarette smoking. However, few studies have investigated differences in anhedonia and reward learning among depressed smokers and depressed nonsmokers. The goal of this study was to examine putative differences in anhedonia and reward learning in depressed smokers (n=36) and depressed nonsmokers (n=44). To this end, participants completed self-report measures of anhedonia and behavioral activation (BAS reward responsiveness scores) and as well as a probabilistic reward task rooted in signal detection theory, which measures reward learning (Pizzagalli, Jahn, & O'Shea, 2005). When considering self-report measures, depressed smokers reported higher trait anhedonia and reduced BAS reward responsiveness scores compared to depressed nonsmokers. In contrast to self-report measures, nicotine-satiated depressed smokers demonstrated greater acquisition of reward-based learning compared to depressed nonsmokers as indexed by the probabilistic reward task. Findings may point to a potential mechanism underlying the frequent co-occurrence of smoking and depression. These results highlight the importance of continued investigation of the role of anhedonia and reward system functioning in the co-occurrence of depression and nicotine abuse. Results also may support the use of treatments targeting reward learning (e.g., behavioral activation) to enhance smoking cessation among individuals with depression.

Nicotine acutely inhibits erectile tumescence by altering heart rate variability.

OBJECTIVE: To examine potential mechanisms underlying nicotine's effects on male sexual arousal by exploring the mediating role of heart rate variability (HRV). METHODS: The sample comprised 22 healthy, nicotine-naïve men (mean age = 20.91 years; standard deviation = 2.43). Data were taken from a double-blind, randomized, placebo-controlled, crossover trial previously completed and published elsewhere. During each laboratory visit, time-domain parameters of HRV (standard deviation of normal-to-normal [NN] intervals, square root of the mean squared difference of successive NN intervals, and percent of NN intervals for which successive heartbeat intervals differed by at least 50 ms [pNN50]) along with the objective (via penile plethysmography) and subjective indices of sexual arousal were assessed. RESULTS: Acute nicotine ingestion (compared with placebo) was associated with dysregulated sympathovagal balance, which in turn was related to relatively reduced erectile tumescence. HRV did not mediate relations between nicotine intake and self-reported indices of sexual arousal. CONCLUSION: HRV mediated the association between nicotine ingestion and erectile capacity. Findings suggest that dysfunctional cardiac autonomic tone may be an underlying mechanism by which nicotine exerts its deleterious effects on erectile health.

Concurrent relations among cigarette smoking status, resting heart rate variability, and erectile response.

INTRODUCTION: Heart rate variability (HRV) is a marker of sympathovagal balance; it has been implicated in erectile function and is also altered by tobacco use. Furthermore, smoking and erectile health are strongly related, given that smokers are at increased risk for erectile dysfunction. Few studies have explored the interrelationships between smoking, HRV, and erectile function concurrently. AIM: The aim of this study was to examine potential mechanisms underlying tobacco's effects on penile hemodynamics by exploring the mediating role of HRV. METHODS: The sample comprised 119 men (smokers = 64; nonsmokers = 55) (mean age 28.90 years; standard deviation (SD) 11.68; range 18-58) selected from the control conditions of three previously published experiments. Participants were free from a history of cardiovascular disease, myocardial infarct, and/or cardiac/cardiovascular medication use. During a laboratory visit, self-report, anthropometric, cardiovascular, and electrocardiographic data were assessed, as well as sexual arousal responses elicited from viewing an erotic film. MAIN OUTCOME MEASURES: Objective sexual arousal indices (circumferential change via penile plethysmography), self-reported erectile function (per the erectile function domain score of the International Index of Erectile Function [IIEF-EF]), and time- (SD of beat-to-beat intervals) and frequency-domain parameters of HRV (ratio of low-frequency [LF] power to high-frequency [HF] power [LF/HF ratio]) were assessed. RESULTS: Being a current long-term cigarette smoker was associated with dysregulated sympathovagal balance (higher LF/HF ratios, indicative of sympathetic nervous system dominance), which in turn showed inverse relations with magnitude of erectile tumescence. HRV did not mediate relations between tobacco use and either IIEF-EF scores or resting penile circumference. CONCLUSIONS: Findings suggest that dysfunctional cardiac autonomic tone may be an underlying mechanism by which tobacco exerts its deleterious effects on erectile health. Further research is necessary to determine whether this relationship is mechanistic in nature, or whether it is better explained by other health factors.

Prospective examination of cigarette smoking among Iraq-deployed and nondeployed soldiers: prevalence and predictive characteristics.

BACKGROUND: Identifying characteristics that influence smoking behavior among military personnel is critical to protect health and operational functioning. PURPOSE: This study prospectively examined rates of cigarette smoking and predictors of changes in smoking behavior as a function of Iraq deployment. METHODS: One thousand eighty-two US Army soldiers (n = 773 Iraq-deployed; n = 309 nondeployed) completed assessments at two sessions [time 1: April 2003-July 2004; time 2: May 2004-July 2004 (nondeployers); January 2005-September 2006 (deployers)]. RESULTS: Approximately 48 % of participants smoked at both time points, with 6 % initiating smoking and 6 % quitting. Smoking initiation was associated with warzone stress exposure; female gender and high military unit support predicted cessation. Military rank and alcohol use were associated with both smoking initiation and cessation. CONCLUSION: Findings highlight the potential benefits of targeting risk factors for cigarette smoking in comprehensive military health programs aimed at smoking prevention and cessation.

Effects of smoking cessation on heart rate variability among long-term male smokers.

BACKGROUND: Cigarette smoking has been shown to adversely affect heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. Conversely, smoking cessation is posited to improve cardiac regulation. PURPOSE: The aim of the present study was to examine the effects of smoking cessation on HRV among a community sample of chronic smokers. METHODS: Sixty-two healthy male smokers enrolled in an 8-week smoking cessation program involving a nicotine transdermal patch treatment. Participants were assessed at baseline (while smoking regularly), at mid-treatment (while using a high-dose patch), and at follow-up, 4 weeks after patch discontinuation. Both time-domain (standard deviation of normal-to-normal (NN) intervals (SDNN), square root of the mean squared difference of successive NN intervals (RMSSD), and percent of NN intervals for which successive heartbeat intervals differed by at least 50 ms (pNN50)) and frequency-domain (low frequency (LF), high frequency (HF), LF/HF ratio) parameters of HRV were assessed at each visit. RESULTS: Successful quitters (n = 20), compared to those who relapsed (n = 42), displayed significantly higher SDNN, RMSSD, pNN50, LF, and HF at follow-up, when both nicotine and smoke free. CONCLUSIONS: Smoking cessation significantly enhances HRV in chronic male smokers, indicating improved autonomic modulation of the heart. Results suggest that these findings may be primarily attributable to nicotine discontinuation rather than tobacco smoke discontinuation alone.

Smoking Status and Exercise in relation to PTSD Symptoms: A Test among Trauma-Exposed Adults.

The present investigation examined the interactive effect of cigarette smoking status (i.e., regular smoking versus non-smoking) and weekly exercise (i.e., weekly metabolic equivalent) in terms of posttraumatic stress (PTSD) symptom severity among a community sample of trauma-exposed adults. Participants included 86 trauma-exposed adults (58.1% female; Mage = 24.3). Approximately 59.7% of participants reported regular (≥ 10 cigarettes per day) daily smoking over the past year. The interactive effect of smoking status by weekly exercise was significantly associated with hyperarousal and avoidance symptom cluster severity (p ≤ .05). These effects were evident above and beyond number of trauma types and gender, as well as the respective main effects of smoking status and weekly exercise. Follow-up tests indicated support for the moderating role of exercise on the association between smoking and PTSD symptoms, such that the highest levels of PTSD symptoms were observed among regular smokers reporting low weekly exercise levels. Theoretical and clinical implications of the findings are discussed.

Predictors of attrition from an expressive writing intervention for sexual abuse survivors.

This study examined predictors of attrition from a clinical trial examining the effects of an expressive writing intervention for sexual problems among female survivors of child sexual abuse. Participants were 124 women all reporting sexual difficulties, who were randomized to a trauma-focused condition (n = 45), an experimental sexual schema-focused condition (n = 37), or a control condition (n = 42). Thirty-five women (28%) dropped out before completing posttreatment assessments. Younger age, less education, and increased use of positive coping strategies were each independently associated with dropout. Results have implications for both researchers and clinicians working with this population, and it is hoped that these data can help bolster retention of those who are more likely to discontinue treatment.

Syncopation and the score.

The score is a symbolic encoding that describes a piece of music, written according to the conventions of music theory, which must be rendered as sound (e.g., by a performer) before it may be perceived as music by the listener. In this paper we provide a step towards unifying music theory with music perception in terms of the relationship between notated rhythm (i.e., the score) and perceived syncopation. In our experiments we evaluated this relationship by manipulating the score, rendering it as sound and eliciting subjective judgments of syncopation. We used a metronome to provide explicit cues to the prevailing rhythmic structure (as defined in the time signature). Three-bar scores with time signatures of 4/4 and 6/8 were constructed using repeated one-bar rhythm-patterns, with each pattern built from basic half-bar rhythm-components. Our manipulations gave rise to various rhythmic structures, including polyrhythms and rhythms with missing strong- and/or down-beats. Listeners (N = 10) were asked to rate the degree of syncopation they perceived in response to a rendering of each score. We observed higher degrees of syncopation in time signatures of 6/8, for polyrhythms, and for rhythms featuring a missing down-beat. We also found that the location of a rhythm-component within the bar has a significant effect on perceived syncopation. Our findings provide new insight into models of syncopation and point the way towards areas in which the models may be improved.

The relationship between resting heart rate variability and erectile tumescence among men with normal erectile function.

INTRODUCTION: Individuals with erectile dysfunction (ED) have been shown to display lower heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. No studies have explored whether HRV is predictive of erectile response among men with clinically normal erectile function. AIM: The study aims to examine associations between resting HRV and objective measures of genital response (i.e., resting penile circumference; erectile tumescence) and self-reported sexual function. METHODS: The sample comprised 59 male community volunteers (mean age = 20.15 years; SD = 2.52) selected from the control conditions of two previously published studies. Participants reported erectile function in the normal range (scoring ≥ 26 on the International Index of Erectile Function [IIEF]) and had no history of cardiovascular disease or myocardial infarct. During a laboratory visit, self-report, anthropometric, cardiovascular, and electrocardiographic data were assessed, as well as resting penile circumference and erectile tumescence in response to viewing an erotic film. MAIN OUTCOME MEASURES: Resting penile responses, erectile tumescence (circumferential change via penile plethysmography), self-reported sexual function per the IIEF, and both time-domain (standard deviation of beat-to-beat [NN] intervals, square root of the mean squared difference of successive NN intervals, and percent of NN intervals for which successive heartbeat intervals differed by at least 50 msec [pNN50]) and frequency-domain (low frequency [LF], high frequency [HF], LF/HF ratio) parameters of HRV were assessed. RESULTS: Higher-resting HF power and lower-resting LF/HF ratio were associated with greater erectile tumescence. There were marginally significant positive associations between mean NN interval and pNN50 and penile tumescence. HRV was not associated with self-reported sexual function or with resting penile circumference. CONCLUSIONS: Results suggested that, among men without ED, relatively elevated parasympathetic tone was predictive of larger erectile tumescence. Limited variance in sexual function scores may have accounted for the lack of association between HRV and IIEF scores.

Association between smoking and heart rate variability among individuals with depression.

BACKGROUND: Both depression and smoking have been independently associated with lower heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. However, no studies have systematically explored the effects of smoking on HRV among depressed patients. PURPOSE: This study examined differences in HRV based on smoking status among depressed individuals. METHODS: Electrophysiological data were examined among 77 adult outpatients without a history of myocardial infarction, who met criteria for major depressive disorder or dysthymia. Frequency domain [low frequency (LF), high frequency (HF), LF/HF ratio, respiratory sinus arrhythmia (RSA)] parameters of HRV, and heart rate and inter-beat interval (IBI) data were compared between depressed smokers (n = 34) and depressed nonsmokers (n = 44). RESULTS: After controlling for covariates, depressed smokers, compared to depressed nonsmokers, displayed significantly lower LF, HF, and RSA. CONCLUSIONS: Among depressed patients, smoking is associated with significantly lower HRV, indicating dysregulated autonomic modulation of the heart.

Visualizing the autophagy pathway in avian cells and its application to studying infectious bronchitis virus.

Autophagy is a highly conserved cellular response to starvation that leads to the degradation of organelles and long-lived proteins in lysosomes and is important for cellular homeostasis, tissue development and as a defense against aggregated proteins, damaged organelles and infectious agents. Although autophagy has been studied in many animal species, reagents to study autophagy in avian systems are lacking. Microtubule-associated protein 1 light chain 3 (MAP1LC3/LC3) is an important marker for autophagy and is used to follow autophagosome formation. Here we report the cloning of avian LC3 paralogs A, B and C from the domestic chicken, Gallus gallus domesticus, and the production of replication-deficient, recombinant adenovirus vectors expressing these avian LC3s tagged with EGFP and FLAG-mCherry. An additional recombinant adenovirus expressing EGFP-tagged LC3B containing a G120A mutation was also generated. These vectors can be used as tools to visualize autophagosome formation and fusion with endosomes/lysosomes in avian cells and provide a valuable resource for studying autophagy in avian cells. We have used them to study autophagy during replication of infectious bronchitis virus (IBV). IBV induced autophagic signaling in mammalian Vero cells but not primary avian chick kidney cells or the avian DF1 cell line. Furthermore, induction or inhibition of autophagy did not affect IBV replication, suggesting that classical autophagy may not be important for virus replication. However, expression of IBV nonstructural protein 6 alone did induce autophagic signaling in avian cells, as seen previously in mammalian cells. This may suggest that IBV can inhibit or control autophagy in avian cells, although IBV did not appear to inhibit autophagy induced by starvation or rapamycin treatment.

Recreational use of erectile dysfunction medications and its adverse effects on erectile function in young healthy men: the mediating role of confidence in erectile ability.

INTRODUCTION: Oral erectile dysfunction medications (EDMs) have become an increasingly popular drug of abuse among young men without a medical indication. In addition to being associated with increased sexual risk behaviors, recreational EDM use may adversely impact psychological aspects of sexual function, primarily by affecting one's confidence in pharmacologically unaided erectile ability. To date, these associations have not been investigated empirically. AIM: This study examined the mediating role of confidence in erectile ability on the concurrent relationship between recreational EDM use and erectile function among young healthy men. A secondary aim was to examine erectile function characteristics among recreational users, prescribed users, and nonusers to control for the possibility that recreational users were using EDMs to treat ED. METHODS: The sample comprised 1,207 sexually active men (mean age = 21.9 years; standard deviation = 4.48) who were recruited from undergraduate institutions within the United States. MAIN OUTCOME MEASURES: Participants completed an online survey assessing frequency of EDM use, as well as levels of sexual function (erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall sexual satisfaction) and levels of confidence in ability to gain and maintain erection, as per the International Index of Erectile Function. RESULTS: Recreational users (N = 72) reported similar erectile function levels compared with nonusers (N = 1,111), and both groups differed from prescribed users (N = 24). Recreational users also reported lower erectile confidence and lower overall satisfaction compared with nonusers. Results were consistent with mediation, in that more frequent EDM use was inversely associated with erectile confidence, which in turn showed negative relations with erectile function. CONCLUSIONS: Confidence in erectile abilities mediates the inverse relationship between recreational EDM use and erectile function. Results underscore the possibility that recreational EDM use among healthy young men may lead to psychogenic ED. Additional longitudinal research is necessary to establish a causal link between these variables.

Association between smoking cessation and sexual health in men.

OBJECTIVE: To provide the first empirical investigation of the association between smoking cessation and indices of physiological and subjective sexual health in men. SUBJECTS AND METHODS: Male smokers, irrespective of erectile dysfunction status, who were motivated to stop smoking ('quitters'), were enrolled in an 8-week smoking cessation programme involving a nicotine transdermal patch treatment and adjunctive counselling. Participants were assessed at baseline (while smoking regularly), at mid-treatment (while using a high-dose nicotine transdermal patch), and at a 4-week post-cessation follow-up. Physiological (circumferential change via penile plethysmography) and subjective sexual arousal indices (continuous self-report), as well as self-reported sexual functioning were assessed at each visit. RESULTS: Intent-to-treat analyses indicated that, at follow-up, successful quitters (n= 20), compared with those who relapsed (n= 45), showed enhanced erectile tumescence responses, and faster onset to reach maximum subjective sexual arousal. Although successful quitters displayed across-session enhancements in sexual function, they did not show a differential improvement compared with unsuccessful quitters. CONCLUSIONS: Smoking cessation significantly enhances both physiological and self-reported indices of sexual health in long-term male smokers, irrespective of baseline erectile impairment. It is hoped that these results may serve as a novel means to motivate men to stop smoking.

Evidence for a curvilinear relationship between sympathetic nervous system activation and women's physiological sexual arousal.

There is increasing evidence that women's physiological sexual arousal is facilitated by moderate sympathetic nervous system (SNS) activation. Literature also suggests that the level of SNS activation may play a role in the degree to which SNS activity affects sexual arousal. We provide the first empirical examination of a possible curvilinear relationship between SNS activity and women's genital arousal using a direct measure of SNS activation in 52 sexually functional women. The relationship between heart rate variability (HRV), a specific and sensitive marker of SNS activation, and vaginal pulse amplitude (VPA), a measure of genital arousal, was analyzed. Moderate increases in SNS activity were associated with higher genital arousal, while very low or very high SNS activation was associated with lower genital arousal. These findings imply that there is an optimal level of SNS activation for women's physiological sexual arousal.

Recreational use of erectile dysfunction medications in undergraduate men in the United States: characteristics and associated risk factors.

Mounting evidence indicates that erectile dysfunction medications (EDMs) have become increasingly used as a sexual enhancement aid among men without a medical indication. Recreational EDM use has been associated with increased sexual risk behaviors, an increased risk for STIs, including incident HIV infection, and high rates of concomitant illicit drug use. The aim of the present study was to investigate the characteristics and associated risk factors for recreational EDM use among young, healthy, undergraduate men. A cross-sectional sample of 1,944 men were recruited from 497 undergraduate institutions within the Unites States between January 2006 and May 2007. The survey assessed patterns of EDM use, as well as demographic, substance use, and sexual behavior characteristics. Four percent of participants had recreationally used an EDM at some point in their lives, with 1.4% reporting current use. The majority of recreational EDM users reported mixing EDMs with illicit drugs and particularly during risky sexual behaviors. Recreational EDM use was independently associated with increased age, gay, or bisexual sexual orientation, drug abuse, lifetime number of sex partners, and lifetime number of "one-night stands." Recreational EDM users also reported a 2.5-fold rate of erectile difficulties compared to nonusers. Overall, recreational use of EDMs was associated with sexual risk behaviors and substance abuse; however, a relatively small proportion of undergraduates reported using EDMs. Results also suggest that a sizable portion of recreational EDM users are heterosexual men, and that use does not solely occur within the environments of venues that cater to men having sex with men.