Miniaturization optimized weapon killing power during the social stress of late pre-contact North America (AD 600-1600)

Before Europeans arrived to Eastern North America, prehistoric, indigenous peoples experienced a number of changes that culminated in the development of sedentary, maize agricultural lifeways of varying complexity. Inherent to these lifeways were several triggers of social stress including population nucleation and increase, intergroup conflict (warfare), and increased territoriality. Here, we examine whether this period of social stress co-varied with deadlier weaponry, specifically, the design of the most commonly found prehistoric archery component in late pre-contact North America: triangular stone arrow tips (TSAT). The examination of modern metal or carbon projectiles, arrows, and arrowheads has demonstrated that smaller arrow tips penetrate deeper into a target than do larger ones. We first experimentally confirm that this relationship applies to arrow tips made from stone hafted onto shafts made from wood. We then statistically assess a large sample (n = 742) of late pre-contact TSAT and show that these specimens are extraordinarily small. Thus, by miniaturizing their arrow tips, prehistoric people in Eastern North America optimized their projectile weaponry for maximum penetration and killing power in warfare and hunting. Finally, we verify that these functional advantages were selected across environmental and cultural boundaries. Thus, while we cannot and should not rule out stochastic, production economizing, or non-adaptive cultural processes as an explanation for TSAT, overall our results are consistent with the hypothesis that broad, socially stressful demographic changes in late pre-contact Eastern North America resulted in the miniaturization–and augmented lethality–of stone tools across the region

Miniaturization optimized weapon killing power during the social stress of late pre-contact North America (AD 600-1600).

Before Europeans arrived to Eastern North America, prehistoric, indigenous peoples experienced a number of changes that culminated in the development of sedentary, maize agricultural lifeways of varying complexity. Inherent to these lifeways were several triggers of social stress including population nucleation and increase, intergroup conflict (warfare), and increased territoriality. Here, we examine whether this period of social stress co-varied with deadlier weaponry, specifically, the design of the most commonly found prehistoric archery component in late pre-contact North America: triangular stone arrow tips (TSAT). The examination of modern metal or carbon projectiles, arrows, and arrowheads has demonstrated that smaller arrow tips penetrate deeper into a target than do larger ones. We first experimentally confirm that this relationship applies to arrow tips made from stone hafted onto shafts made from wood. We then statistically assess a large sample (n = 742) of late pre-contact TSAT and show that these specimens are extraordinarily small. Thus, by miniaturizing their arrow tips, prehistoric people in Eastern North America optimized their projectile weaponry for maximum penetration and killing power in warfare and hunting. Finally, we verify that these functional advantages were selected across environmental and cultural boundaries. Thus, while we cannot and should not rule out stochastic, production economizing, or non-adaptive cultural processes as an explanation for TSAT, overall our results are consistent with the hypothesis that broad, socially stressful demographic changes in late pre-contact Eastern North America resulted in the miniaturization-and augmented lethality-of stone tools across the region

Preeclampsia prediction with blood pressure measurements: A global external validation of the ALSPAC models

Objective: The prediction of preeclampsia in pregnancy has resulted in a plethora of prognostic models. Yet, very few make it past the development stage and most fail to influence clinical practice. The timely identification of high-risk pregnant women could deliver a tailored antenatal care regimen, particularly in low-resource settings. This study externally validated and calibrated previously published models that predicted the risk of preeclampsia, based on blood pressure (BP) at mul- tiple time points in pregnancy, in a geographically diverse population. Methods: The prospective INTERBIO-21st Fetal Study included 3,391 singleton pregnancies from Brazil, Kenya, Pakistan, South Africa, Thailand and the UK, 2012–2018. Preeclampsia prediction was based on baseline characteristics, BP and deviation from the expected BP trajectory at multiple time points in pregnancy. The prediction rules from the Avon Longitudinal Study of Parents and Children (ALSPAC) were implemented in the INTERBIO-21st cohort. Results: Model discrimination was similar to the development cohort. Performance was best with baseline characteristics and a BP measurement at 34 weeks’ gestation (AUC 0.85, 95 % CI 0.80–0.90). The ALSPAC models largely overestimated the true risk of preeclampsia incidence in the INTERBIO-21st cohort. Conclusions: After recalibration, these prediction models could potentially serve as a risk stratifying tool to help identify women who might benefit from increased surveillance during pregnancy

The Cedar Project: Historical trauma, sexual abuse and HIV risk among young Aboriginal people who use injection and non-injection drugs in two Canadian cities

Recent Indigenist scholarship has situated high rates of traumatic life experiences, including sexual abuse, among Indigenous peoples of North America within the larger context of their status as colonized peoples. Sexual abuse has been linked to many negative health outcomes including mental, sexual and drug-related vulnerabilities. There is a paucity of research in Canada addressing the relationship between antecedent sexual abuse and negative health outcomes among Aboriginal people including elevated risk of HIV infection. The primary objectives of this study were to determine factors associated with sexual abuse among participants of the Cedar Project, a cohort of young Aboriginal people between the ages of 14 and 30 years who use injection and non-injection drugs in two urban centres in British Columbia, Canada; and to locate findings through a lens of historical and intergenerational trauma. We utilized post-colonial perspectives in research design, problem formulation and the interpretation of results. Multivariate modeling was used to determine the extent to which a history of sexual abuse was predictive of negative health outcomes and vulnerability to HIV infection. Of the 543 eligible participants, 48% reported ever having experienced sexual abuse; 69% of sexually abused participants were female. The median age of first sexual abuse was 6 years for both female and male participants. After adjusting for sociodemographic variables and factors of historical trauma, sexually abused participants were more likely to have ever been on the streets for more than three nights, to have ever self-harmed, to have suicide ideation, to have attempted suicide, to have a diagnosis of mental illness, to have been in the emergency department within the previous 6 months, to have had over 20 lifetime sexual partners, to have ever been paid for sex and to have ever overdosed. The prevalence and consequences of sexual abuse among Cedar Project participants are of grave concern. Sexual trauma will continue to impact individuals, families and communities until unresolved historical trauma is meaningfully addressed in client-driven, culturally safe programming.Sexual abuse Historical trauma Aboriginal young people Canada Substance dependence HIV Cedar Project