Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6

Background <br/> The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene. <br/> Results Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East. <br/> Conclusions <br/> A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast

Dietary Patterns Associated with Alzheimer?s Disease and Related Chronic Disease Risk: A Review

The world’s population is growing older due to improved healthcare and nutrition. As a result, Alzheimer’s disease (AD) prevalence is rapidly increasing. The focus of the current research climate is shifting from understanding AD pathology and diagnosis to primary prevention and intervention strategies. Diet represents one potential intervention strategy accessible to all. Accumulating evidence suggests diet plays a major role in risk and development of AD and AD-related chronic diseases of the periphery like cardiovascular disease (CVD) and diabetes. This paper reviews studies that have explored the relationship between “a priori” dietary patterns, AD and AD-related chronic disease risk. The dietary patterns we will review are the healthy eating index, healthy diet indicator, recommended food score, and the Mediterranean diet (MeDi). Our review of the literature suggests a generally positive association between healthy diet patterns, AD and AD-related chronic disease risk; however the magnitude of the protective effect is modest in many studies. Consequently, we can only confidently conclude that the MeDi is associated with reduced AD risk, and further studies on the remaining indices need to be carried out. It is our opinion that a combination of dietary scores could predict overall dietary quality and chronic disease risk to a greater extent than one score individually. Analysis in multi-ethnic cohorts, investigating combinations of scores must be completed before firm conclusions can be reached on the ideal combination of scores. Obtaining further insight into the association between dietary patterns, AD and AD-related chronic disease risk may help in prioritizing public health efforts and provide a stronger basis for recommendations to improve dietary patterns

Irradiation damage on CrNbTaVWx high entropy alloys

ABSTRACT: CrNbTaVWx high-entropy alloys have been developed for plasma facing components to be applied in nuclear fusion reactors. The CrNbTaVWx (x = 1 and 1.7) compositions were prepared by ball milling and consolidated at 1600 degrees C under 90 MPa. To study the irradiation resistance of these materials, deuterium plasmas were used to irradiate the samples in the PF-1000U facility with 1 and 3 discharges. Structural changes before and after irradiation were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Nuclear reaction analysis was carried out with 1000 and 2300 keV 3He+ ion beams to evaluate the profile and amount of retained deuterium on the irradiated samples. After irradiation, the sample with higher W content revealed swelling and melting for all discharges, while in the case of CrNbTaVW only blisters were observed. The deuterium retention was higher for CrNbTaVW1.7 when compared with CrNbTaVW for 3 discharges applied.info:eu-repo/semantics/publishedVersio

In situ experiments with synchrotron high-energy x-rays of Ni-Ti alloys produced by powder metallurgy

The structural evolution that takes place during the homogenization heat treatments of powder metallurgical Ni-Ti- alloys was studied by in situ synchrotron diffraction. It is proposed to get a deeper understanding of this phenomenon by using different types of thermal/mechanical cycles

Investigation of single phase Cu2ZnSnxSb1-xS4 compounds processed by mechanochemical synthesis

ABSTRACT: The copper zinc tin sulfide (CZTS) compound is a promising candidate as an alternative absorber material for thin-film solar cells. In this study, we investigate the direct formation of Cu1.92ZnSnx(Sb1-x)S-4 compounds [CZT(A)S], with x = 1, 0.85, 0.70, and 0.50, via a mechanochemical synthesis (MCS) approach, starting from powders of the corresponding metals, zinc sulfide, and sulfur. The thermal stability of the CZT(A)S compounds was evaluated in detail by in situ synchrotron high-energy x-ray diffraction measurements up to 700 degrees C. The CZT(A)S compounds prepared via MCS revealed a sphalerite-type crystal structure with strong structural stability over the studied temperature range. The contribution of the MCS to the formation of such a structure at room temperature is analyzed in detail. Additionally, this study provides insights into the MCS of CZTS-based compounds: the possibility of a large-scale substitution of Sn by Sb and the production of single phase CZT(A)S with a Cupoor/Zn-poor composition. A slight increase in the band gap from 1.45 to 1.49-1.51 eV was observed with the incorporation of Sb, indicating that these novel compounds can be further explored for thin-film solar cells.info:eu-repo/semantics/publishedVersio

Behavior of Cu-Y2O3 and CuCrZr-Y2O3 composites before and after irradiation

ABSTRACT: The Cu-Y2O3 and CuCrZr-Y2O3 materials have been devised as thermal barriers in nuclear fusion reactors. It is expected that in the nuclear environments, the materials should be working on extreme conditions of irradiation. In this work the Cu-Y2O3 and CuCrZr-Y2O3 were prepared and then irradiated in order to understand the surface irradiation resistance of the material. The composites were prepared in a glove box and consolidated with spark plasma sintering. The microstructures revealed regions of Y2O3 dispersion and Y2O3 agglomerates both in the Cu matrix and in the CuCrZr. The irradiated samples did not show any surface modification indicating that the materials seem to be irradiation resistant in the present situation. The thermal conductivity values for all the samples measured are lower than pure Cu and higher than pure W, however are higher than those expected, and therefore, the application of these materials as thermal barriers is compromised.info:eu-repo/semantics/publishedVersio

Improvement of Mechanical Properties with Non-Equimolar CrNbTaVW High Entropy Alloy

ABSTRACT: CrNbTaVWx with (x = 1 and 1.7) high entropy alloys have been devised for thermal barriers between the plasma-facing tungsten tiles and the copper-based heat sink in the first wall of fusion nuclear reactors. These novel materials were prepared by ball milling and consolidated by Upgrade Field Assisted Sintering Technology at 1873 K under an applied pressure of 90 MPa for 10 min. In this work, the structural and mechanical properties of these materials were evaluated. Consolidated samples presented a major phase with a bcc-type structure with lattice parameter value of 0.316 nm for CrNbTaVW and CrNbTaVW1.7 compositions. Moreover, observation of the microstructures evidences also two minor phases: Ta-Nb-Cr and Ta-V rich (in which carbon is detected). Despite the similarity in the structural properties of these two alloys, their mechanical properties are distinct. The flexural stress for the sample with higher amount of W (CrNbTaVW1.7) is higher by 50% in the 298-873 K range, with an increased strain to fracture, which can be associated with reduced brittleness caused by the additional W incorporation.info:eu-repo/semantics/publishedVersio

Characterization of smart MARFOS NiTi shape memory alloys

In the present study, structural characterization of NiTi smart shape memory al-loys (SMAs), produced by an alternative powder metallurgy approach named mechanically ac-tivated reactive forging (MARFOS), was carried out by means of transmission electron micros-copy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed that MARFOS materials had a multiphase nanocrystalline structure. In addition, the transformation behaviour associated with the shape memory effect of the MARFOS aged mate-rials was studied with differential scanning calorimetry (DSC). Multiple-step martensitic trans-formations could be observed in aged materials

Nonconventional production technologies for NiTi shape memory alloys

The development of new production technologies for NiTi Shape Memory Alloys (SMAs) is always challenging. Recently, we introduced two powder metallurgical (PM) processing routes involving mechanical activation of elemental powder mixtures and densification through extrusion or forging. Those processes were named Mechanically Activated Reactive Extrusion Synthesis (MARES) and Mechanically Activated Reactive FOrging Synthesis (MARFOS). Heat treatments were performed in order to adjust the B2-NiTi matrix composition, yielding a microstructure consisting of a homogeneous dispersion of Ni4Ti3 precipitates embedded in nanocrystalline B2-NiTi matrix. In the present study, we demonstrate the viability of those PM processes for producing NiTi SMAs. With insitu X-ray diffraction and differential scanning calorimetry it is shown that B2-NiTi matrix undergo a B2« R«B19 two-step phase transformatio

DRY BEAN CULTIVAR IAC ALVORADA UNDER DIFFERENT RATES OF \u3ci\u3eRHIZOBIUM\u3c/i\u3e INOCULANT IN THE PLANTING FURROW

INTRODUCTION: No publications were found regarding liquid inoculation in the planting furrow of dry bean, which indicates a demand for investigations to assist the producer in deciding which method of inoculation to adopt. Thus, the aim of this study was to evaluate the viability of liquid inoculation in the planting furrow and determine the best application rate of inoculant, using the dry bean cultivar IAC Alvorada. MATERIALS AND METHODS: A field experiment was conducted in a no-till planting system in the 2014/2015 crop season in a Latossolo Vermelho distrófico in the municipality of Lambari, MG, Brazil. The experimental design was randomized blocks with three replications and eight treatments, involving five application rates of liquid inoculant in the planting furrow (0, 120, 240, 480, and 720 mL ha-1), liquid seed inoculation (40 mL kg-1), and two controls without inoculation: one with N-urea (80 kg ha-1 N, ½ at sowing and ½ in topdressing, between the V3 and V4 stages of the crop cycle) and another without mineral N. The experimental unit (14.4 m2) consisted of six four-meter-length rows, spaced at 0.6 m, and the area effectively used was the four central rows. All the plots received base fertilization of 110 kg ha-1 of P2O5 (simple superphosphate) and 40 kg ha-1 of K2O (potassium chloride), mechanically applied during furrowing. In addition, all levels of inoculation received 20 kg Nurea ha-1, so as to meet the recommendations of Soares et al. (2016). Sowing was manual at the density of 15 seeds per meter and the cultivar used was IAC Alvorada, of semi-upright plant architecture and moderate resistance to anthracnose (Carbonell et al., 2008)