Beyond multiregional and simple out-of-Africa models of human evolution

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Extending qubit coherence by adaptive quantum environment learning

Decoherence, resulting from unwanted interaction between a qubit and its environment, poses a serious challenge towards the development of quantum technologies. Recently, researchers have started analysing how real-time Hamiltonian learning approaches, based on estimating the qubit state faster than the environmental fluctuations, can be used to counteract decoherence. In this work, we investigate how the back-action of the quantum measurements used in the learning process can be harnessed to extend qubit coherence. We propose an adaptive protocol that, by learning the qubit environment, narrows down the distribution of possible environment states. While the outcomes of quantum measurements are random, we show that real-time adaptation of measurement settings (based on previous outcomes) allows a deterministic decrease of the width of the bath distribution, and hence an increase of the qubit coherence. We numerically simulate the performance of the protocol for the electronic spin of a nitrogen-vacancy centre in diamond subject to a dilute bath of $^{13}$C nuclear spin, finding a considerable improvement over the performance of non-adaptive strategies

Uniformity and Diversity in Handaxe Shape at the End of the Acheulean in Southwest Asia

This study examines parameters, causes, and spatio-temporal patterns of handaxe shape variation from Tabun cave in the Levant, and Khall Amayshan 4B and Khabb Musayyib in northern Arabia. These assemblages span the range of most pointy to most rounded handaxes found anywhere during the Acheulean. The AGMT3D program is used to conduct high resolution geometric morphometric analysis of handaxe form from 3D models. Shape variation is tested against blank type, allometry, and reduction intensity. None of these factors appears to be a strong influence, but there are significant assemblage-wise differences in form, suggesting the different shapes were intentionally produced. The analysis quantifies a pattern of high diversity in the assemblages from Tabun versus low diversity in the shorter occupations at the Arabian sites. We suggest possible explanations of emerging specificity in utilitarian functions, as well as the manifestation of social identities in artefacts at the end of the Acheulean

Ghajn Klieb, (Rabat, Malta)

Between October and December 1999 a team of local and foreign undergraduates from the University of Malta carried out a survey of the site at Ghajn Klieb outside Rabat. The exercise constituted the practical part of a unit on the Principles of Archaeological Surveying directed by Dr Nicholas Vella of the Department of Classics & Archaeology. For the survey the team was joined by Hanna Stager, a graduate of the same department, who also researched some of the references used in this article. Initial reconnaissance of the site was carried out on 15 October 1999 with Nathaniel Cutajar and Michelle B uhagiar, Curator and Assistant Curator respectively at the National Museum of Archaeology. The scatter of surface ceramics and the existence of previously known and unknown features revealed the extent and potential of the site. It was decided that the locality of Ghajn Klieb warranted systematic study that could be carried out in various stages, with the longterm aim being an assessment of human activity and cultural behaviour at the site. The Museums Department gave the go-ahead for this project, and permission to collect the surface ceramics was granted. This short report is intended to give an outline of the work undertaken to date. Emphasis is placed on the field methods adopted and on the presentation of what we believe to be worth talking about at this stage. An effort is here made by the senior author to unravel the collaborative nature of the exercise by lending weight to individual thoughts and interpretations that arose while work progressed in the field.peer-reviewe

Evaluating refugia in recent human evolution in Africa

Homo sapiens have adapted to an incredible diversity of habitats around the globe. This capacity to adapt to different landscapes is clearly expressed within Africa, with Late Pleistocene Homo sapiens populations occupying savannahs, woodlands, coastlines and mountainous terrain. As the only area of the world where Homo sapiens have clearly persisted through multiple glacial-interglacial cycles, Africa is the only continent where classic refugia models can be formulated and tested to examine and describe changing patterns of past distributions and human phylogeographies. The potential role of refugia has frequently been acknowledged in the Late Pleistocene palaeoanthropological literature, yet explicit identification of potential refugia has been limited by the patchy nature of palaeoenvironmental and archaeological records, and the low temporal resolution of climate or ecological models. Here, we apply potential climatic thresholds on human habitation, rooted in ethnographic studies, in combination with high-resolution model datasets for precipitation and biome distributions to identify persistent refugia spanning the Late Pleistocene (130–10 ka). We present two alternate models suggesting that between 27% and 66% of Africa may have provided refugia to Late Pleistocene human populations, and examine variability in precipitation, biome and ecotone distributions within these refugial zones. This article is part of the theme issue ‘Tropical forests in the deep human past’

Pulmonary rehabilitation in chronic obstructive pulmonary disease : outcomes in a 12 week programme

Objective. The optimal time-frame for pulmonary rehabilitation (PR) in patients diagnosed with chronic obstructive pulmonary disease (COPD) is still debated. A 12 week programme was designed looking at whether the benefits were reached at or before a 12 week period of PR for COPD patients. Method. Seventy-five patients (59 males, 16 females) aged 40 75 years were referred from the local general hospital in Malta. Baseline assessments were carried out on all patients 2 weeks before initiation of the programme. Sixty patients were eligible to start a twice-weekly, 12 week multidisciplinary programme delivered after the screening process. The Six-Minute Walk Test (6MWT), dyspnoea score using the Borg scale, spirometry testing, plethysmography, COPD Assessment Tool (CAT) score, St George's Respiratory Questionnaire (SGRQ) and Hospital and Anxiety scale score were monitored at 4 weekly intervals throughout the 12 weeks of PR for these COPD patients. Results. The 6MWT distance increased by a mean total of 132.45 m (p < 0.001) by 12 weeks, with the highest change recorded in the first 4 weeks for the milder COPD patients. Lung function test improvements were marginal. Borg scale readings at rest and following exertion decreased significantly from weeks 0 to 4 but remained fairly constant thereafter. The Body mass index, airway Obstruction, Dyspnoea, and Exercise capacity (BODE) index, SGRQ and CAT score values decreased significantly throughout the weeks irrespective of the initial Medical Research Council score. Anxiety scoring decreased significantly by 12 weeks, while the depression rating improved by 8 weeks. Conclusion. These findings show that 12 weeks of PR in this cohort of COPD patients resulted in clinically significant changes in functional outcome measures which are supported by statistically significant changes in health-related quality of life measures. In milder COPD cases, by 4 weeks of PR gains in exercise tolerance had already resulted. The more severe group required more time to obtain improvements. Therefore, hospitals could organize shorter PR programmes for larger numbers of patients with milder COPD.peer-reviewe

Spin–layer locking of interlayer excitons trapped in moiré potentials

Van der Waals heterostructures offer attractive opportunities to design quantum materials. For instance, transition metal dichalcogenides (TMDs) possess three quantum degrees of freedom: spin, valley index, and layer index. Further, twisted TMD heterobilayers can form moir\'e patterns that modulate the electronic band structure according to atomic registry, leading to spatial confinement of interlayer exciton (IXs). Here we report the observation of spin-layer locking of IXs trapped in moir\'e potentials formed in a heterostructure of bilayer 2H-MoSe$_2$ and monolayer WSe$_2$. The phenomenon of locked electron spin and layer index leads to two quantum-confined IX species with distinct spin-layer-valley configurations. Furthermore, we observe that the atomic registries of the moir\'e trapping sites in the three layers are intrinsically locked together due to the 2H-type stacking characteristic of bilayer TMDs. These results identify the layer index as a useful degree of freedom to engineer tunable few-level quantum systems in two-dimensional heterostructures.Comment: 10 pages, 4 figures. Supplementary Material available at: https://www.dropbox.com/s/8331cfoasdofwkq/Brotons-Gisbert_Suppl_Info.pdf?dl=

Automated renal segmentation in healthy and chronic kidney disease subjects using a convolutional neural network

Purpose: Total Kidney Volume (TKV) is an important measure in renal disease detection and monitoring. We developed a fully automated method to segment the kidneys from T2-weighted magnetic resonance images (MRI) to calculate TKV of healthy control (HC) and chronic kidney disease (CKD) patients.Methods: This automated method uses machine learning, specifically a 2-dimensional (2D) convolutional neural network (CNN), to accurately segment the left and right kidneys from T2-weighted MRI data. The dataset consisted of 30 HC subjects and 30 CKD patients. The model was trained on 50 manually defined HC and CKD kidney segmentations. The model was subsequently evaluated on 50 test data sets, comprising data from five HCs and five CKD patients each scanned five times in a scan session to enable comparison of the precision of the CNN and manual segmentation of kidneys.Results: The unseen test data processed by the 2D CNN had a mean Dice score of 0.93 ± 0.01. The difference between manual and automatically computed TKV was 1.2 ± 16.2 ml with a mean surface distance of 0.65 ± 0.21 mm. The variance in TKV measurements from repeat acquisitions on the same subject was significantly lower using the automated method compared to manual segmentation of the kidneys.Conclusion: The 2D CNN method provides fully automated segmentation of the left and right kidney and calculation of TKV in under ten seconds on a standard office computer, allowing high data throughput and is a freely available executable

Comparative analysis of Middle Stone Age artifacts in Africa (CoMSAfrica).

Spatial and temporal variation among African Middle Stone Age (MSA) archeological assemblages provide essential cultural and behavioral data for understanding the origin, evolution, diversification, and dispersal of Homo sapiens—and, possibly, interactions with other hominin taxa. However, incorporating archeological data into a robust framework suited to replicable, quantitative analyses that can be integrated with observations drawn from studies of the human genome, hominin morphology, and paleoenvironmental contexts requires the development of a unified comparative approach and shared units of analysis. The CoMSAfrica workshop presented here, has the ambition to build bridges between researchers and research regions in Africa on these paramount topics

Human interactions with tropical environments over the last 14,000 years at Iho Eleru, Nigeria

The Ihò Eléérú (or Iho Eleru) rock shelter, located in Southwest Nigeria, is the only site from which Pleistocene-age hominin fossils have been recovered in western Africa. Excavations at Iho Eleru revealed regular human occupations ranging from the Later Stone Age (LSA) to the present day. Here, we present chronometric, archaeobotanical, and paleoenvironmental findings, which include the taxonomic, taphonomic, and isotopic analyses of what is the only Pleistocene faunal assemblage documented in western Africa. Our results indicate that the local landscape surrounding Iho Eleru, although situated within a regional open-canopy biome, was forested throughout the past human occupation of the site. At a regional scale, a shift from forest- to savanna-dominated ecotonal environment occurred during a mid-Holocene warm event 6,000 years ago, with a subsequent modern reforestation of the landscape. Locally, no environmental shift was observable, placing Iho Eleru in a persistent forested “island” during the period of occupation