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This chapter examines the role of selection in driving certain aspects of pelvic morphology, particularly the differences between mediolateral breadths and anteroposterior breadths. The chapter is divided into three sections, representing the three key selection pressures researchers have spent the most time on – namely, obstetrics, locomotion and thermoregulation. Data for the role of each of these on pelvic morphology are considered, as is discussion of the myriad ways human populations have mixed and matched morphological traits to manage these selection pressures. Clearly, there is not a single strategy for handling the interactive nature of these pressures.
In this chapter, we discuss evidence about the evolutionary forces that have shaped the evolution of the human pelvis, both in its entirety as well as portions of the pelvis, focusing on studies that have investigated pelvic evolution using experimental and quantitative genetic methods. These methods are tied to information from Chapter 4 about pelvis development, with emphasis placed on the importance of understanding the difficulty of tying development and growth with evolutionary processes. Special attention is placed on the concept of the palimpsest. Further, we review these findings in light of three principal hypotheses broadly offered about the processes that selected for pelvic shape (as reviewed in Chapters 2 and 3): locomotion, obstetric sufficiency and thermoregulation. We show from multiple studies that the human pelvis evolved in response to natural selection as well as through neutral evolutionary processes (e.g. genetic drift). A key conclusion from these studies is that parts of the pelvis evolved in different manners in response to these (and other) selection factors; thus, the shape of the human pelvis reflects a modular response to various sources of selection.
This chapter provides an overview of the anatomy of the primate pelvis, with a particular focus on the features of the hominoid (ape) and human pelvic morphologies. Underlying sources of morphological variation such as phylogenetic signals, sexual dimorphism and obstetric function are examined, as well as general patterns of pelvic anatomical variation within Homo sapiens.
In light of the various sources of evidence presented in the preceding chapters, we are left to conclude that the human (in the broadest sense of recent humans and their ancestors) pelvis represents various experiments in evolution. A diversity in pelvic sizes and shapes has marked hominin history, as each population and each species responded to selection pressures in sometimes unique and sometimes convergent ways. These were situated in the distinctive population histories of each of these groups, creating a mosaic of patterns underlain both by responses to evolution and changing patterns of covariance within development. To understand the diversity we observe among fossils, as well as variation within recent humans, we must therefore cultivate a multidisciplinary expertise in biomechanics, kinematics, fossil evidence, developmental biology and evolutionary theory. This book represents an attempt at bringing together these various sources of evidence to better understand the factors, patterns and potential processes that shaped the evolution of the pelvis.
Even before the focus on bipedalism as the ‘hallmark’ of the human lineage (Robinson, 1972), interest in the pelvis was stimulated by discussions across different disciplines, including the growing field of obstetrics (see review in Walrath, 2003), as well as by multiple fossil discoveries (Pycraft, 1930; Dart, 1949). It was also clear at the outset that the pelvis was going to serve as a crucial part of the evolutionary history of humans, given that it had obvious functional implications in its role in locomotion, which included dramatic differences between other species grouped with humans taxonomically and then phylogenetically, including the African and Asian apes.
To investigate pelvis evolution and to understand the sources of its variation, we must comprehend its development. We review developmental processes that form the pelvis from three perspectives: cell layers and tissues, genomic information and overall growth. At tissue level, the pelvis forms largely from lateral plate mesoderm as well as from somites. The os coxa forms from cartilaginous precursor tissues that grow and ossify, especially in two major regions that become the ischiopubis and the ilium. The sacrum and coccyx form from multiple ossification centres. Numerous secondary ossification centres form, with the last fusing by the mid-twenties. The importance of multiple genes and molecular factors are discussed, including interactions among and differences in timing and locations of expression, emphasising Islet1, Emx2, Pbx and Hox. We review the importance of differences in timing of ossification among skeletal elements, their interactions with mechanical loading and sex hormones, and environmental factors affecting individual growth. These processes are linked to morphological integration and are the origins of the morphological variation on which evolutionary forces act.
This chapter examines the fossil record of hominoid and hominin pelvic remains from the Miocene through to the Late Pleistocene. The interpretation of functional demands shaping hominin pelvic morphology including locomotion, obstetrics and thermoregulation are discussed, as well as evidence for pelvic sexual dimorphism in hominin species. The long-standing view of a relatively linear pattern of hominin pelvic evolution from Australopiths, through early Homo, to Neanderthals, broken only by the appearance of the somewhat divergent morphology of Homo sapiens is examined in light of recent fossil pelvis discoveries that point to greater diversity in the hominin pelvic morphology. These fossils add to evidence from elsewhere in the postcranium that indicate there were multiple ways to be a bipedal hominin.
There is a paucity of long-term prospective disaster studies of the psychological sequelae among survivors.
At 1½ and 25 years after the Spitak earthquake, 142 early adolescents from two cities were assessed: Gumri (moderate–severe exposure) and Spitak (very severe exposure). The Gumri group included treated and not-treated subjects, while the Spitak group included not-treated subjects. Instruments included: DSM-III-R PTSD-Reaction Index (PTSD-RI); DSM-5 PTSD-Checklist (PCL); Depression Self-Rating Scale (DSRS); and Center for Epidemiological Studies-Depression Scale (CES-D).
(1) Between 1½ and 25 years, PTSD rates and mean scores decreased significantly in the three groups (over 50%). However, at 25 years 9.1–22.4% met DSM-5 PTSD criteria. (2) At 1½ years, the Spitak group had higher PTSD-RI (p < 0.001) and DSRS scores (p < 0.001) compared to the Gumri-not-treated group. At 25 years, the Spitak group that had experienced fewer post-earthquake adversities (p < 0.03), had a greater decrease in PTSD-RI scores (p < 0.02), and lower CES-D scores (p < 0.01). (3) Before treatment, PTSD-RI and DSRS scores did not differ between the Gumri-treated and not-treated groups. At 25-years, the Gumri-treated group showed a greater decrease in PTSD-RI scores (p < 0.03), and lower mean PTSD-RI (p < 0.02), PCL (p < 0.02), and CES-D (p < 0.01) scores. (4) Predictors of PTSD symptom severity at 25-years included: home destruction, treatment, social support, post-earthquake adversities, and chronic medical illnesses.
Post-disaster PTSD and depressive symptoms can persist for decades. Trauma-focused treatment, alleviation of post-disaster adversities, improving the social ecology, and monitoring for chronic medical illnesses are essential components of recovery programs.
Prevention of Clostridioides difficile infection (CDI) is a national priority and may be facilitated by deployment of the Targeted Assessment for Prevention (TAP) Strategy, a quality improvement framework providing a focused approach to infection prevention. This article describes the process and outcomes of TAP Strategy implementation for CDI prevention in a healthcare system.
Hospital A was identified based on CDI surveillance data indicating an excess burden of infections above the national goal; hospitals B and C participated as part of systemwide deployment. TAP facility assessments were administered to staff to identify infection control gaps and inform CDI prevention interventions. Retrospective analysis was performed using negative-binomial, interrupted time series (ITS) regression to assess overall effect of targeted CDI prevention efforts. Analysis included hospital-onset, laboratory-identified C. difficile event data for 18 months before and after implementation of the TAP facility assessments.
The systemwide monthly CDI rate significantly decreased at the intervention (β2, −44%; P = .017), and the postintervention CDI rate trend showed a sustained decrease (β1 + β3; −12% per month; P = .008). At an individual hospital level, the CDI rate trend significantly decreased in the postintervention period at hospital A only (β1 + β3, −26% per month; P = .003).
This project demonstrates TAP Strategy implementation in a healthcare system, yielding significant decrease in the laboratory-identified C. difficile rate trend in the postintervention period at the system level and in hospital A. This project highlights the potential benefit of directing prevention efforts to facilities with the highest burden of excess infections to more efficiently reduce CDI rates.
Globally, China is among the ‘saltiest’ nations. In order to support current nationwide salt reduction initiatives, we investigated Chinese consumers’ knowledge, beliefs and behaviours related to salt intake and salt reduction.
A cross-sectional face-to-face survey was carried out, focusing on salt knowledge, beliefs and behaviours related to salt intake and salt reduction, perceptions of salt reduction responsibility and support for different national strategies.
The survey was carried out in China mainland.
Consumers (n 2444) from six of seven major geographical regions in China participated in the survey. After data cleaning, a sample of 2430 was included in the final analysis.
A majority of Chinese consumers believed that salt added during home cooking was the biggest contributor to their salt intake. Knowledge gaps existed in the awareness of salt hidden in certain foods and flavouring products. Chinese consumers in general were interested in lowering their salt intake. They were aware of salt reduction tools, but the adoption level was low. Consumers expressed strong support for promotion of salt-restriction spoons and public education, but not fiscal policies (e.g. salt-related tax or subsidies). In terms of individual differences, education status demonstrated a substantial impact on salt reduction knowledge and behaviour.
There is still big room to ‘shake’ Chinese consumers’ salt habit. The present study provides important evidence and consumer insights to support China’s efforts to meet its salt reduction targets.
Lamb live weight is one of the key drivers of profitability on sheep farms. Previous studies in Ireland have estimated genetic parameters for live weight and carcass composition traits using a multi-breed population rather than on an individual breed basis. The objective of the present study was to undertake genetic analyses of three lamb live weight and two carcass composition traits pertaining to purebred Texel, Suffolk and Charollais lambs born in the Republic of Ireland between 2010 and 2017, inclusive. Traits (with lamb age range in parenthesis) considered in the analyses were: pre-weaning weight (20 to 65 days), weaning weight (66 to 120 days), post-weaning weight (121 to 180 days), muscle depth (121 to 180 days) and fat depth (121 to 180 days). After data edits, 137 402 records from 50 372 lambs across 416 flocks were analysed. Variance components were derived using animal linear mixed models separately for each breed. Fixed effects included for all traits were contemporary group, age at first lambing of the dam, parity of the dam, a gender by age of the lamb interaction and a birth type by rearing type of the lamb interaction. Random effects investigated in the pre-weaning and weaning weight analyses included animal direct additive genetic, dam maternal genetic, litter common environment, dam permanent environment and residual variances. The model of analysis for post-weaning, muscle and fat depth included an animal direct additive genetic and litter common environment effect only. Significant direct additive genetic variation existed in all cases. Direct heritability for pre-weaning weight ranged from 0.14 to 0.30 across the three breeds. Weaning weight had a direct heritability ranging from 0.17 to 0.27 and post-weaning weight had a direct heritability ranging from 0.15 to 0.27. Muscle and fat depth heritability estimates ranged from 0.21 to 0.31 and 0.15 to 0.20, respectively. Positive direct correlations were evident for all traits. Results revealed ample genetic variation among animals for the studied traits and significant differences between breeds to suggest that genetic evaluations could be conducted on a per-breed basis.
This book provides a synthetic overview of all evidence concerning the evolution of the morphology of the human pelvis, including comparative anatomy, clinical and experimental studies, and quantitative evolutionary models. By integrating these lines of research, this is the first book to bring all sources of evidence together to develop a coherent statement about the current state of the art in understanding pelvic evolution. Second, and related to this, the volume is the first detailed assessment of existing paradigms about the evolution of the pelvis, especially the obstetric dilemma. The authors argue that there are many 'dilemmas', but these must be approached using a testable methodology, rather than on the proviso of a single paradigm. The volume clearly contributes to greater scientific knowledge about human variation and evolution, and has implications for clinicians working within reproductive health. A thought-provoking read for students, researchers and professionals in the fields of biological anthropology, human evolutionary anthropology, paleoanthropology, bioarchaeology, biology, developmental biology and obstetrics.
Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy data demonstrating that sulfur is accommodated predominantly in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mechanism. Minor sulfide and sulfite peaks in the X-ray photoelectron spectra, however, also indicate that more complex substitution mechanisms incorporating S2– and S4+ are possible. Incorporation of S6+ through clino-anhydrite-type substitution results in an excess of M2+ cations, which previous workers have suggested is accommodated by auxiliary substitution of OH– for O2–. However, Raman data show no indication of OH–, and instead we suggest charge imbalance is accommodated through F– substituting for O2–. The accommodation of S in the monazite-(Ce) results in considerable structural distortion that may account for relatively high contents of ions with radii beyond those normally found in monazite-(Ce), such as the heavy rare earth elements, Mo, Zr and V. In contrast to S-bearing monazite-(Ce) in other carbonatites, S-bearing monazite-(Ce) at Eureka formed via a dissolution–precipitation mechanism during prolonged weathering, with S derived from an aeolian source. While large S-bearing monazite-(Ce) grains are likely to be rare in the geological record, formation of secondary S-bearing monazite-(Ce) in these conditions may be a feasible mineral for dating palaeo-weathering horizons.