Reconstructing 1200 years of Hydroclimate Variability in the Southern Margins of the Arabian Desert: Insights From a Paleo-Lake in Southern Yemen

The climate of the Arabian Desert is not well documented during the past two millennia due to the scarcity of continuous and well-dated terrestrial archives in the region. Reliable interpretation from the climatic records from this region are pivotal for identifying periodicities of inter-annual to multi-decadal variability and trends driven by shifts in position of the Intertropical Convergence Zone (ITCZ) and the strength of the monsoons. A high-resolution multiproxy approach is presented for a ∼3.3 m composite core, GBW, from a karst lake located in Ghayl ba Wazir, southern Yemen. Sedimentary proxies, including particle size distribution, coupled with magnetic susceptibility (MS) and geochemistry (XRF), provide a comprehensive picture of sediment depositional changes that may be linked to climate and environmental variability over the southern Arabian Desert. The chronology of the GBW core is provided by five radiocarbon (14C) dates from terrestrial macrofossils (wood and twigs) extracted from sediment samples and indicates the core extends to ∼900 CE. Our data indicates generally wetter conditions from 930 to 1400 CE corresponding to the “Medieval climate anomaly (MCA)” followed by arid phases during 1,410–1700 CE coinciding with the “Little Ice Age (LIA)”. Evidence for a drier LIA include high authigenic calcium precipitation [Ca/(Al + Fe + Ti)], decreased TOC/TIC values, and gypsum precipitation, whereas the wetter MCA is characterized by higher detrital element ratios (Ti/Al, K/Al, Rb/Sr), and increased TOC/TIC and deposition of finer sediments (EM1). Furthermore, end-member mixing analyses (EMMA) derived from the grain-size distribution (EM2 and EM3) corroborates the deposition of coarser silt sediment through wind erosion and production of carbonate sand during the LIA concurrently with low lake levels under generally dry conditions. Aridity during the LIA is consistent with evidence and theory for weakened boreal summer monsoons during intervals of northern hemisphere cooling.

The variability of volatile organic compounds in the indoor air of clinical environments

The development of clinical breath-analysis is confounded by the variability of background volatile organic compounds (VOC). Reliable interpretation of clinical breath-analysis at individual, and cohort levels requires characterisation of clinical-VOC levels and exposures. Active-sampling with thermal-desorption/gas chromatography-mass spectrometry recorded and evaluated VOC concentrations in 245 samples of indoor air from three sites in a large NHS provider trust in the UK over 27 months. Data deconvolution, alignment and clustering isolated 7344 features attributable to VOC and described the variability (composition and concentration) of respirable clinical VOC. 328 VOC were observed in more than 5% of the samples and 68 VOC appeared in more than 30% of samples. Common VOC were associated with exogenous and endogenous sources and 17 VOC were identified as seasonal differentiators. The presence of metabolites from the anaesthetic sevoflurane, and putative-disease biomarkers in room air, indicated that exhaled VOC were a source of background-pollution in clinical breath-testing activity. With the exception of solvents, and PPE waxes, exhaled VOC concentrations above 3 µg m-3 are unlikely to arise from room air contamination, and in the absence of extensive survey-data, this level could be applied as a threshold for inclusion in studies, removing a potential environmental confounding-factor in developing breath-based diagnostics.

Isotope data from amino acids indicate Darwin’s ground sloth was not an herbivore

Fossil sloths are regarded as obligate herbivores for reasons including peculiarities of their craniodental morphology and that all living sloths feed exclusively on plants. We challenge this view based on isotopic analyses of nitrogen of specific amino acids, which show that Darwin’s ground sloth Mylodon darwinii was an opportunistic omnivore. This direct evidence of omnivory in an ancient sloth requires reevaluation of the ecological structure of South American Cenozoic mammalian communities, as sloths represented a major component of these ecosystems across the past 34 Myr. Furthermore, by analyzing modern mammals with known diets, we provide a basis for reliable interpretation of nitrogen isotopes of amino acids of fossils. We argue that a widely used equation to determine trophic position is unnecessary, and that the relative isotopic values of the amino acids glutamate and phenylalanine alone permit reliable reconstructions of trophic positions of extant and extinct mammals.

Classification of Bundle Branch Blocks with QRS Templates Extracted from 12-lead ECGs

Being non-invasive, cheap and widely available, the 12-lead electrocardiogram (ECG) is a standard method to assess cardiac function. Still, its reliable interpretation requires specialized knowledge and experience, rendering a second opinion valuable. We evaluated the performance of machine learning based classification of 11,705 healthy and bundle branch block 12-lead ECGs from 3 open databases. For each lead of the ECG signal, a representative QRS-complex template was extracted automatically. Principal component analysis (PCA) was applied to the concatenated, normalized and rescaled QRS signals to reduce their dimensionality. Multilayer perceptron and support-vector machine classifiers were trained using the principal components of weighted and non-weighted QRS template signals as input data. Classifiers achieved F1 scores between 0.92 and 0.96 on the test set for different input configurations. Anomaly based weighting slightly improved the performance of the classifiers. Neither class-wise PCA for feature extraction nor adding information on sex, gender and electrical heart axis to the input data yielded considerable improvement of the F1 scores. The achieved classification accuracy is similar to deep learning classifier performances and should generalize robustly to other ECG datasets. Our results suggest that this simple and well interpretable approach based on morphological signal characteristics is suitable for automatically and non-invasively identifying bundle branch block pathologies in clinical or smart electronics contexts.

An Archaeological Experiment to Reconstruct a Compound Bow of the Sintashta Culture Stepnoe Burial Ground

The article presents data from an international experimental study on the reconstruction of the Sintashta culture compound bow. The project is carried out by a collective of researchers from Russia and Greece as part of the grant program of the international association of experimental archeology EXARC. The high role of long-range weapons in the life of the Sintashta society has been repeatedly noted by researchers. The production processes that directly affect the practice of using weapons, as well as the issues of the evolution of weapons, are poorly understood. A complex of horn parts from barrow 4, pit 13 of Stepnoe burial ground (Chelyabinsk region) was chosen as the object for the reconstruction of the Sintashta bow as the most constructively interesting examples. For a reliable interpretation of this category of artifacts, the authors reviewed the global context of the design features of finds of the Bronze Age bows. Analysis of the materials revealed evolutionary trends in the development of long-range weapons, as well as localizing various traditions. Based on experimental studies, the project participants obtained the first conclusions about possible design solutions and the practice of using ancient weapons. Full-scale modeling allowed us to conclude that the Sintashta bow was a hybrid type of long bow, compound type. This type of bow is unique and may reflect the combination of the “steppe” and “european” traditions of the manufacture of long-range weapons. The article is intended to show the main types of bow construction of the Bronze Age and to determine the place of the Sintashta materials in this context, as well as to present the variants of experimental solutions for bow modeling.

Discriminant models of the possibility of occurrence and course of psoriasis in men of the general group and different somatotypes depending on the characteristics of anthropo-somatotypological indicators

Significant prevalence and multifactorial occurrence of psoriasis are the main reasons why this disease has been studied for years by scientists in the field of dermatology. Finding tools to predict the occurrence and severity of this disease is one of the key unrealized areas of modern medicine in the field of skin diseases. The purpose of the study is to build and analyze discriminant models of the possibility and features of psoriasis course in Ukrainian men without and taking into account the somatotype, depending on the structure and size of the body. Anthropometric and somatotypological examination of 82 practically healthy and 100 patients with mild and severe psoriasis was performed. Construction of discriminant models of the possibility of occurrence and features of psoriasis depending on anthropo-somatotypological indicators is performed in the license package “Statistica 5.5”. It was found that men of the general group and representatives of the mesomorphic somatotype can reliably interpret the obtained classification indicators both between healthy and patients with psoriasis of different course, and between men with psoriasis of mild and severe course (correctness 84.1% of cases, statistics Wilks’ Lambda=0.074, р<0.001 in the general group, correctness 83.6% of cases, statistics Wilks’ Lambda=0.077, р<0.001 in mesomorphic somatotype). In men of endo-mesomorphic somatotype, a reliable interpretation of the obtained classification indicators is possible only between healthy and psoriatic men (correctness 84.6%, statistics Wilks’ Lambda=0.027, р<0.001). Discriminant models in men of the general group include body diameters and SFT (44.4% each) and the fat component of body weight (11.1% each); in men of mesomorphic somatotype – body diameters (57.1%), SFT (28.6%) and body surface area (14.3%); in men of endo-mesomorphic somatotype – body diameters (60.0%) and SFT on the thigh and the height of the finger anthropometric point (20.0% each). The greatest contribution to discrimination in men of the general group and representatives of the mesomorphic somatotype is made by shoulder width, and in men of endo-mesomorphic somatotype – shoulder width, interspinous and intercristal distances. The results obtained, especially in the division of men into somatotypes, indicate a high genetic predisposition to psoriasis.

CuBi-MeAn Customized Pipeline for Metagenomic Data Analysis

1.AbstractWhole genome shotgun sequencing is a powerful to study microbial community is a given environment. Metagenomic binning offers a genome centric approach to study microbiomes. There are several tools available to process metagenomic data from raw reads to the interpretation there is still lack of standard approach that can be used to process the metagenomic data step by step. In this study CuBi-MeAn (Customizable Binning and Metagenomic Analysis) create a customizable and flexible processing pipeline, to process the metagenomic data and generate results for further interpretation.This study aims to perform metagenomic binning to enhance taxonomical classification, functional potentials, and interactions among microbial populations in environmental systems. This customized pipeline which is comprised of a series of genomic/metagenomic tools designed to recover better quality results and reliable interpretation of the system dynamics for the given systems. For this reason, a metagenomic data processing pipeline is developed to evaluate metagenomic data from three environmental engineering projects.The use of our pipeline was demonstrated and compared on three different datasets that were of different sizes, from different sequencing platforms, and generated from three different environmental sources. By designing and developing a flexible and customized pipeline, this study has showed how to process large metagenomic data sets with limited resources. This result not only would help to uncover new information from environmental samples, but also, could be applicable to any other metagenomic studies across various disciplines.

Positronium Confined in Nanocavities: The Role of Electron Exchange Correlations

Positronium atoms (Ps) are commonly employed as a probe to characterize nanometric or subnanometric voids or vacancies in nonmetallic materials, where Ps can end up confined. The annihilation lifetime of a trapped Ps is strongly modified by pickoff and depends on the cavity size and on the electron density in the confining cavity surface. Here, we develop a theory of the Ps annihilation in nanocavities based on the fundamental role of the exchange correlations between the Ps-electron and the outer electrons, which are not usually considered but must be considered to correctly theorize the pickoff annihilation processes. We obtain an important relation connecting the two relevant annihilation rates (for the p-Psand the o-Ps) with the electron density, which has the property of being totally independent of the geometrical characteristics of the nanoporous medium. This general relation can be used to gather information on the electron density and on the average cavity radius of the confining medium, starting from the experimental data on PALS annihilation spectra. Moreover, by analyzing our results, we also highlight that a reliable interpretation of the PALS spectra can only be obtained if the rule of 1/3 between the intensities of p-Psand o-Pslifetimes can be fulfilled.

Responding to Assessment for Learning

Assessment for learning (AfL) is a major approach to educational assessment that relies heavily on pedagogical practices, such as involving students in assessment, making transparent objectives and criteria, and asking open-ended questions that provoke higher order thinking. In this perspective piece, I argue that without the possibility of opening classroom activities to systematic and rigorous inspection and evaluation, AfL fails to be assessment. AfL activities happen ephemerally in classrooms, leading to in-the-moment and on-the-fly interpretations and decisions about student learning. In these contexts, determination of the degree of error in those judgements does not happen. Because human performance is so variable and because the samples teachers use to make judgements are not robustly representative, there is considerable error in their judgements about student learning. Nonetheless, despite the difficulties seen in putting AfL into practice, they appear to be good classroom teaching practices. In contrast, assessment proper requires careful inspection of data so that alternative explanations can be evaluated, leading to a preference for the most valid and reliable interpretation of performance evidence. Psychometric methods not only quantify amounts or qualities of performance, but also evaluate the degree to which judges agree with each other, leading to confidence in the validity and reliability of insights. Consequently, because AfL activities lack the essential characteristics of paying attention to error and methods of minimising its impact on interpretations, I recommend we stop thinking of AfL as assessment, and instead position it as good teaching.

ANALYSIS OF THE CURRENT STATE OF RESEARCHES OF THE DEPOSITION OF ASPHALT-RESINOUS SUBSTANCES, PARAFFIN, AND MODELING METHODS. REVIEW PART II: WAX DEPOSITION

The mechanism of paraffin formation in transport pipes is briefly discussed. A kinetic model of the formation and wax deposition from oil is proposed. Comparison of the model with the available experimental data gave satisfactory results. The review considers software tools for modeling the wax deposition process. It is noted that the simulation results are not always applicable to real field cases. For a more reliable interpretation, the scaling effect must be taken into account. In the work various technologies for wax removal are considered