Throughout human history, large-scale migrations have facilitated the formation of populations with ancestry from multiple previously separated populations. This process leads to subsequent shuffling ...of genetic ancestry through recombination, producing variation in ancestry between populations, among individuals in a population, and along the genome within an individual. Recent methodological and empirical developments have elucidated the genomic signatures of this admixture process, bringing previously understudied admixed populations to the forefront of population and medical genetics. Under this theme, we present a collection of recent PLOS Genetics publications that exemplify recent progress in human genetic admixture studies, and we discuss potential areas for future work.
As the last habitable continent colonized by humans, the site of multiple domestication hotspots, and the location of the largest Pleistocene megafaunal extinction, South America is central to human ...prehistory. Yet remarkably little is known about human population dynamics during colonization, subsequent expansions, and domestication. Here we reconstruct the spatiotemporal patterns of human population growth in South America using a newly aggregated database of 1,147 archaeological sites and 5,464 calibrated radiocarbon dates spanning fourteen thousand to two thousand years ago (ka). We demonstrate that, rather than a steady exponential expansion, the demographic history of South Americans is characterized by two distinct phases. First, humans spread rapidly throughout the continent, but remained at low population sizes for 8,000 years, including a 4,000-year period of 'boom-and-bust' oscillations with no net growth. Supplementation of hunting with domesticated crops and animals had a minimal impact on population carrying capacity. Only with widespread sedentism, beginning ~5 ka, did a second demographic phase begin, with evidence for exponential population growth in cultural hotspots, characteristic of the Neolithic transition worldwide. The unique extent of humanity's ability to modify its environment to markedly increase carrying capacity in South America is therefore an unexpectedly recent phenomenon.
Domestic minor sex trafficking (DMST) is an increasingly recognized traumatic crime premised upon the control, abuse, and exploitation of youth. By definition, DMST is the “recruitment, harboring, ...transportation, provision, or obtaining of a person for the purpose of a commercial sex act” within domestic borders, in which the person is a U.S. citizen or lawful permanent resident under the age of 18 years. The present study described the demographics, psychosocial features, and trafficking experiences (e.g., environments of recruitment, relationship to trafficker, solicitation) of DMST victims. A total of 25 medical records of patients under the age of 18 who disclosed their involvement in DMST to medical providers between August 1, 2013, and November 30, 2015, were retrospectively reviewed. The majority of patients were female, and the mean age was 15.4 years old. Most patients lived at home and/or were accompanied at the evaluation by a parent/guardian. High rates of alcohol or substance use/abuse (92%), being placed in a group home or child protective services (CPS) custody (28%), a history of runaway behavior (60%), and/or exposure to other child maltreatment (88%) were identified. Our data indicated variation in reported trafficking experiences; however, patients commonly reported an established relationship with their trafficker (60%) and recruitment occurred primarily as a result of financial motivation (52%). Patients were prevalently recruited in settings where there were face-to-face interactions (56%), whereas the solicitation of sex-buyers occurred primarily online (92%). Victims who disclosed involvement in DMST had complicated psychosocial histories that may have rendered them susceptible to their exploitation, and reported a variety of DMST experiences perpetuated by traffickers. Although preliminary in nature, this study provided empirical evidence of the predisposing factors, motivations, and experiences of victimized youth uniquely from the perspective of patients who sought medical care.
Abstract Study Objective To describe the clinical characteristics of patients referred for domestic minor sex trafficking (DMST) in order to improve identification and intervention. Design ...Retrospective cohort study. Setting The Lawrence A. Aubin, Sr. Child Protection Center at Hasbro Children’s Hospital where patients are evaluated by child abuse pediatricians in outpatient, emergency department and inpatient settings. Participants A total of 41 patients under the age of 18 referred for the evaluation of DMST involvement between August 1st , 2013 and March 30th , 2015. Main Outcome Measure(s) We collected demographic, social-environmental, medical, and psychiatric variables from the medical records of patients referred for evaluation who have self-disclosed, been reported with evidence, and/or have histories that place them at high risk for DMST involvement. Results Children had frequent contact with medical providers, with 81% seen in the year prior to referral for DMST. Childhood maltreatment and family dysfunction were identified (sexual abuse 57%, parental substance abuse 60%) in the 41 patients. Children had medical problems (e.g. sexually transmitted infection 27%), psychiatric needs (e.g. acute suicidality 20%, at least one prior psychiatric admission 46%) and substance use (88%). While 63% had run-away and 42% lived in a group home placement, 68% currently lived at home and 71% presented with a parent/guardian or relative. Conclusion Children referred for DMST present frequently to physicians and have complex medical and psychiatric needs. Medical providers’ increased awareness of this health issue would inform victim identification and intervention.
Humans have undergone large migrations over the past hundreds to thousands of years, exposing ourselves to new environments and selective pressures. Yet, evidence of ongoing or recent selection in ...humans is difficult to detect. Many of these migrations also resulted in gene flow between previously separated populations. These recently admixed populations provide unique opportunities to study rapid evolution in humans. Developing methods based on distributions of local ancestry, we demonstrate that this sort of genetic exchange has facilitated detectable adaptation to a malaria parasite in the admixed population of Cabo Verde within the last ~20 generations. We estimate that the selection coefficient is approximately 0.08, one of the highest inferred in humans. Notably, we show that this strong selection at a single locus has likely affected patterns of ancestry genome-wide, potentially biasing demographic inference. Our study provides evidence of adaptation in a human population on historical timescales.
The American College of Surgeons NSQIP has developed a risk calculator (RC) to assist patients and surgeons with difficult decisions. The aim of this analysis was to determine the accuracy of the RC ...in patients undergoing elective and emergent colorectal operations.
From January 2013 through December 2015, seventy-five patients undergoing emergent colorectal operations were paired by date with 75 patients having elective colorectal operations. Patient data were entered into the RC. Actual postoperative outcomes, derived from NSQIP data, were compared with those predicted by the RC.
Emergent and elective patients differed (p < 0.05) with respect to age, functional status, American Society of Anesthesiologists class, steroid use, wound class, COPD, and chronic renal insufficiency. The RC accurately predicted outcomes in elective patients. Outcomes were significantly worse (p < 0.05) after the emergent operations. In emergent cases, the RC underestimated serious complications and length of stay and overestimated discharge to a skilled nursing facility (all p < 0.05).
The American College of Surgeons NSQIP RC accurately predicts outcomes for elective colorectal operations. Predicted and actual outcomes are significantly better in patients undergoing elective colon operations compared with those undergoing emergent procedures. The RC should be used with caution in emergent cases, as it has the potential to underestimate serious complications and length of stay, and overestimate discharge to skilled nursing facility. Refinement of the tool to include procedure complexity and diagnosis terms might improve its accuracy in emergent cases.
To determine the prevalence of incidental rib fractures identified by chest radiograph (CXR) obtained for indications unrelated to accidental trauma or nonaccidental trauma (NAT), and describe the ...histories associated with cases of incidental rib fractures and their proposed etiologies. It is hypothesized that incidental rib fractures are rare and alternative explanations for rib fractures occasionally used in a medico-legal context such as minor accidental trauma, undiagnosed medical conditions, and transient metabolic bone disturbances are unlikely to be the etiology of incidental rib fractures.
A retrospective chart review of sequential CXRs of children ages 0 to <2 years was conducted from January 1, 2011 to October 31, 2016. CXRs were obtained in the emergency department, general pediatric or intensive care units, or outpatient pediatric clinics. Data collected included demographics, CXR indication and findings, history of cardiopulmonary resuscitation, laboratory and additional imaging results, and incidental rib fracture descriptions and proposed etiologies.
A total of 7530 patients underwent 9720 CXRs associated with unique clinical encounters. Five CXRs had incidental rib fractures identified, making the prevalence of CXRs with incidental rib fractures in this cohort <0.1%. Of 5 identified incidental cases, mean age was 3.6 months, 3 were concerning for NAT, 1 was confirmed NAT, and 1 had radiographic findings consistent with osteopenia of prematurity.
Identification of incidental rib fracture on CXR is rare. When detected in the absence of corresponding trauma history and/or objective laboratory or radiographic metabolic abnormalities, work-up for NAT should be pursued.
Stress management programs improve efficacy in aviation, military, and professional sports; however, similar educational strategies have not been adopted in surgical training. We have evaluated the ...effectiveness of a stress management program for surgical residents.
From 2011 to 2016, 137 surgical residents participated in a prospective, blinded study. The intervention group (n = 65) underwent training in self-awareness, focus, relaxation, positive self-talk, visualization, and team building. All participants subsequently completed a high-stress trauma simulation, requiring diagnosis and management of a life-threatening problem. Study endpoints included measures of procedural efficiency, and physiologic and subjective measurements of anxiety.
Residents with stress training came to an accurate diagnosis 21% faster than controls (mean diagnosis time: 2.2 vs. 2.8 min; p = 0.04), and performed with greater technical accuracy (mean OSAT scores: 9.4 vs. 8.9; p = 0.03). Both cohorts exhibited similar physiologic and subjective anxiety metrics after simulation.
Stress management education may enhance technical performance in surgical trainees during simulation. This underscores the need for early, comprehensive stress training in surgical residency.
•This is a prospective trial of 137 surgical residents who took part in a stress training program.•Participants and controls subsequently took part in a high-stress surgical simulation.•Residents who completed stress training performed more accurately and quickly.•Both cohorts exhibited similar measures of physiologic and subjective anxiety.
PDF
