ABSTRACT
The questions of when and how humans reached Sahul, the Pleistocene continent of Australia and New Guinea, has remained a central issue of Australian archaeology since its development as an ...academic discipline in the mid‐twentieth century. Modelling this event has persistently appealed to minimal assumptions – the simplest watercraft, the shortest routes, the smallest viable colonising groups. This paper argues that Australian archaeology can no longer ignore the way our understanding of this initial colonisation is being reshaped by current genomic research. It reviews this evidence and concludes that a colonising wave of hundreds or perhaps low thousands of people was involved. If correct, it suggests that we need to rethink our models, modify or discard the minimalist assumptions that have so far driven them and consider how this different paradigm affects our understanding of early settlement in Sahul.
Résumé
La question de savoir quand et comment les hommes ont atteint Sahul, le continent pléistocène regroupant l'Australie et la Nouvelle‐Guinée, persiste comme une problématique centrale de l'archéologie australienne depuis son essor en tant que discipline universitaire au milieu du vingtième siècle. La modélisation de cet événement s'est appuyée de façon récurrente sur des présupposés minimalistes, impliquant les moyens de navigation les plus simples, les routes les plus courtes, les groupes de colonisation viable les plus restreints. Ce papier soutient que l'archéologie australienne ne peut plus ignorer combien notre compréhension de ce peuplement initial se trouve aujourd'hui redéfinie par la recherche génomique en cours. Il passe en revue les données et conclue que plusieurs centaines ou quelques milliers de personnes ont participé à cette vague de peuplement. Si cette hypothèse est correcte, elle implique que nous repensions nos modèles, que nous modifiions ou abandonnions les présupposés minimalistes qui ont jusqu’à présent défini ceux‐ci et que nous analysions comment ce nouveau paradigme influence notre compréhension du premier peuplement de Sahul.
The questions of when and how humans reached Sahul, the Pleistocene continent of Australia and New Guinea, has remained a central issue of Australian archaeology since its development as an academic discipline in the mid‐twentieth century. Modelling this event has persistently appealed to minimal assumptions – the simplest watercraft, the shortest routes, the smallest viable colonising groups. This paper argues that Australian archaeology can no longer ignore the way our understanding of this initial colonisation is being reshaped by current genomic research. It reviews this evidence and concludes that a colonising wave of hundreds or perhaps low thousands of people was involved. If correct, it suggests that we need to rethink our models, modify or discard the minimalist assumptions that have so far driven them and consider how this different paradigm affects our understanding of early settlement in Sahul.
Anatomically modern humans (Homo sapiens, AMH) began spreading across Eurasia from Africa and adjacent Southwest Asia about 50,000–55,000 years ago (ca. 50–55 ka). Some have argued that human ...genetic, fossil, and archaeological data indicate one or more prior dispersals, possibly as early as 120 ka. A recently reported age estimate of 65 ka for Madjedbebe, an archaeological site in northern Sahul (Pleistocene Australia–New Guinea), if correct, offers what might be the strongest support yet presented for a pre–55-ka African AMH exodus. We review evidence for AMH arrival on an arc spanning South China through Sahul and then evaluate data from Madjedbebe.We find that an age estimate of >50 ka for this site is unlikely to be valid. While AMH may have moved far beyond Africa well before 50–55 ka, data from the region of interest offered in support of this idea are not compelling.
Many existing cohorts contain a range of relatedness between genotyped individuals, either by design or by chance. Haplotype estimation in such cohorts is a central step in many downstream analyses. ...Using genotypes from six cohorts from isolated populations and two cohorts from non-isolated populations, we have investigated the performance of different phasing methods designed for nominally 'unrelated' individuals. We find that SHAPEIT2 produces much lower switch error rates in all cohorts compared to other methods, including those designed specifically for isolated populations. In particular, when large amounts of IBD sharing is present, SHAPEIT2 infers close to perfect haplotypes. Based on these results we have developed a general strategy for phasing cohorts with any level of implicit or explicit relatedness between individuals. First SHAPEIT2 is run ignoring all explicit family information. We then apply a novel HMM method (duoHMM) to combine the SHAPEIT2 haplotypes with any family information to infer the inheritance pattern of each meiosis at all sites across each chromosome. This allows the correction of switch errors, detection of recombination events and genotyping errors. We show that the method detects numbers of recombination events that align very well with expectations based on genetic maps, and that it infers far fewer spurious recombination events than Merlin. The method can also detect genotyping errors and infer recombination events in otherwise uninformative families, such as trios and duos. The detected recombination events can be used in association scans for recombination phenotypes. The method provides a simple and unified approach to haplotype estimation, that will be of interest to researchers in the fields of human, animal and plant genetics.
Summary Background Hyperglycaemia after acute stroke is a common finding that has been associated with an increased risk of death. We sought to determine whether treatment with ...glucose-potassium-insulin (GKI) infusions to maintain euglycaemia immediately after the acute event reduces death at 90 days. Methods Patients presenting within 24 h of stroke onset and with admission plasma glucose concentration between 6·0–17·0 mmol/L were randomly assigned to receive variable-dose-insulin GKI (intervention) or saline (control) as a continuous intravenous infusion for 24 h. The purpose of GKI infusion was to maintain capillary glucose at 4–7 mmol/L, with no glucose intervention in the control group. The primary outcome was death at 90 days, and the secondary endpoint was avoidance of death or severe disability at 90 days. Additional planned analyses were done to determine any differences in residual disability or neurological and functional recovery. The trial was powered to detect a mortality difference of 6% (sample size 2355), with 83% power, at the 5% two-sided significance level. This study is registered as an International Standard Randomised Controlled Trial (number ISRCTN 31118803) Findings The trial was stopped due to slow enrolment after 933 patients were recruited. For the intention-to-treat data, there was no significant reduction in mortality at 90 days (GKI vs control: odds ratio 1·14, 95% CI 0·86–1·51, p=0·37). There were no significant differences for secondary outcomes. In the GKI group, overall mean plasma glucose and mean systolic blood pressure were significantly lower than in the control group (mean difference in glucose 0·57 mmol/L, p<0·001; mean difference in blood pressure 9·0 mmHg, p<0·0001). Interpretation GKI infusions significantly reduced plasma glucose concentrations and blood pressure. Treatment within the trial protocol was not associated with significant clinical benefit, although the study was underpowered and alternative results cannot be excluded.
Per- and polyfluoroalkyl substances (PFAS) make up a large group of persistent anthropogenic chemicals which are difficult to degrade and/or destroy. PFAS are an emerging class of contaminants, but ...little is known about the long-term health effects related to exposure. In addition, technologies to identify levels of contamination in the environment and to remediate contaminated sites are currently inadequate. In this opinion-type discussion paper, a team of researchers from the University of Connecticut and the University at Albany discuss the scientific challenges in their specific but intertwined PFAS research areas, including rapid and low-cost detection, energy-saving remediation, the role of T helper cells in immunotoxicity, and the biochemical and molecular effects of PFAS among community residents with measurable PFAS concentrations. Potential research directions that may be employed to address those challenges and improve the understanding of sensing, remediation, exposure to, and health effects of PFAS are then presented. We hope our account of emerging problems related to PFAS contamination will encourage a broad range of scientific experts to bring these research initiatives addressing PFAS into play on a national scale.
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•PFAS receive extensive attention as a class of emerging contaminants.•Exposure, health effects, sensing, and remediation of PFAS are focused on.•Scientific challenges for emerging PFAS contaminants are discussed.•Potential research directions to address those challenges are presented.
The pyrophilic primate hypothesis Parker, Christopher H.; Keefe, Earl R.; Herzog, Nicole M. ...
Evolutionary anthropology,
March/April 2016, Letnik:
25, Številka:
2
Journal Article
Recenzirano
Members of genus Homo are the only animals known to create and control fire. The adaptive significance of this unique behavior is broadly recognized, but the steps by which our ancestors evolved ...pyrotechnic abilities remain unknown. Many hypotheses attempting to answer this question attribute hominin fire to serendipitous, even accidental, discovery. Using recent paleoenvironmental reconstructions, we present an alternative scenario in which, 2 to 3 million years ago in tropical Africa, human fire dependence was the result of adapting to progressively fire‐prone environments. The extreme and rapid fluctuations between closed canopy forests, woodland, and grasslands that occurred in tropical Africa during that time, in conjunction with reductions in atmospheric carbon dioxide levels, changed the fire regime of the region, increasing the occurrence of natural fires. We use models from optimal foraging theory to hypothesize benefits that this fire‐altered landscape provided to ancestral hominins and link these benefits to steps that transformed our ancestors into a genus of active pyrophiles whose dependence on fire for survival contributed to its rapid expansion out of Africa.
Hawkes, O'Connell, and Coxworth comment on Gurven and Hill criticisms on family provisioning which is not the only reason men hunt. According to him, Gurven and Hill imply that he and his colleagues ...previous work inappropriately discounted the contribution of men's hunting to Ache and Hadza diets.
Global food production needs to increase in order to meet the demands of an ever growing global population. As resources are finite, the most feasible way to meet this demand is to minimize losses ...and improve efficiency. Regular monitoring of factors like animal health, soil and water quality for example, can ensure that the resources are being used to their maximum efficiency. Existing monitoring techniques however have limitations, such as portability, turnaround time and requirement for additional reagents. In this work, we explore the use of micro- and nano-scale electrode devices, for the development of an electrochemical sensing platform to digitalize a wide range of applications within the agri-food sector. With this platform, we demonstrate the direct electrochemical detection of pesticides, specifically clothianidin and imidacloprid, with detection limits of 0.22 ng/mL and 2.14 ng/mL respectively, and nitrates with a detection limit of 0.2 µM. In addition, interdigitated electrode structures also enable an in-situ pH control technique to mitigate pH as an interference and modify analyte response. This technique is applied to the analysis of monochloramine, a common water disinfectant. Concerning biosensing, the sensors are modified with bio-molecular probes for the detection of both bovine viral diarrhea virus species and antibodies, over a range of 1 ng/mL to 10 µg/mL. Finally, a portable analogue front end electronic reader is developed to allow portable sensing, with control and readout undertaken using a smart phone application. Finally, the sensor chip platform is integrated with these electronics to provide a fully functional end-to-end smart sensor system compatible with emerging Agri-Food digital decision support tools.
Behavioral Ecology and Archaeology Bird, Douglas W.; O'Connell, James F.
Journal of archaeological research,
06/2006, Letnik:
14, Številka:
2
Journal Article
Recenzirano
Behavioral ecology is the study of adaptive behavior in relation to social and environmental circumstances. Analysts working from this perspective hold that the reproductive strategies and ...decision-making capacities of all living organisms—including humans—are shaped by natural selection. Archaeologists have been using this proposition in the study of past human behavior for more than 30 years. Significant insights on variation in prehistoric human subsistence, life history, social organization, and their respective fossil and archaeological consequences have been among the more important results.
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