The Archaeofauna from Xaro on the Okavango Delta in northern Botswana

We report on the fauna from the sites of Xaro 1 and Xaro 2 located on the Okavango Delta in northern Botswana. Carbon isotopes from two human graves at Xaro Lodge located approximately 500 m south of Xaro 1 suggest an economy oriented toward wild plants, fish and game similar to that of the modern baNoka, or ‘River Bushmen’. The faunal remains from Xaro 1 and 2 corroborate this suggestion.Pottery from the Early Iron Age, radiocarbon dates from the Later Iron Age, and glass beads from the European trade indicate there were two occupations at both sites, one belonging to the 18th and 19th centuries and an earlier one containing ceramics consistent with a first millennium AD date. The fauna from both occupations is dominated by fish and Chelonia (likely tortoise or terrapin). The people also hunted a variety of game animals, most of which are associated with aquatic conditions. Sheep remains were recovered from the later occupation of Xaro 1.http://www.journals.co.za/ej/ejour_nfi_ditsong.htmlam2013cp201

Oxidação da pirita e seus efeitos em argamassas de cimento Portland sujeitas ao ataque por sulfatos de origem interna

RESUMO O ataque por sulfatos de origem interna é resultante da reação química entre os íons Fe2+ e SO4 2-, provenientes da oxidação de agregados sulfetados, e os compostos da pasta cimentícia, e tende a promover a degradação do concreto devido formação de produtos expansivos que geram fissuração e desagregação do material. Neste trabalho, a morfologia da pirita, presente em alguns tipos de agregado, foi avaliada. O mineral foi utilizado em substituição parcial à areia (10%, em massa) na dosagem de argamassas, para estudo das modificações microestruturais e da variação dimensional linear sob envelhecimento natural durante 42 dias. A caracterização microestrutural foi executada em equipamento FEG/SEM com sonda analítica de EDS. Verificou-se, na superfície da pirita oxidada, a formação de óxidos de ferro, os quais afetaram a interface entre a pasta de cimento e o agregado nos materiais produzidos com a pirita. Quanto a variação dimensional, a argamassa apresentou apenas contrações durante o período de estudo. Verificou-se a ocorrência de fissuração e a predominância na formação de cristais aciculares de etringita aos 42 dias enquanto aos 90 dias a presença de gipsita predomina. Óxidos de ferro oriundos da oxidação da pirita são evidentes nas argamassas aos 90 dias

Magnetic resonance spectroscopy with transcranial direct current stimulation to explore the underlying biochemical and physiological mechanism of the human brain: A systematic review

A large body of molecular and neurophysiological evidence connects synaptic plasticity to specific functions and energy metabolism in particular areas of the brain. Furthermore, altered plasticity and energy regulation has been associated with a number of neuropsychiatric disorders. A favourable approach enabling the modulation of neuronal excitability and energy in humans is to stimulate the brain using transcranial direct current stimulation (tDCS) and then to observe the effect on neurometabolites using magnetic resonance spectroscopy (MRS). In this way, a well‐defined modulation of brain energy and excitability can be achieved using a dedicated tDCS protocol to a predetermined brain region. This systematic review was guided by the preferred reporting items for systematic reviews and meta‐analysis and summarises recent literature studying the effect of tDCS on neurometabolites in the human brain as measured by proton or phosphorus MRS. Limitations and recommendations are discussed for future research. The findings of this review provide clear evidence for the potential of using tDCS and MRS to examine and understand the effect of neurometabolites in the in vivo human brain

A robust method for the detection of small changes in relaxation parameters and free water content in the vicinity of the substantia nigra in Parkinson’s disease patients

Alterations in the substantia nigra are strongly associated with Parkinson’s disease. However, due to low contrast and partial volume effects present in typical MRI images, the substantia nigra is not of sufficient size to obtain a reliable segmentation for region-of-interest based analysis. To combat this problem, the approach proposed here offers a method to investigate and reveal changes in quantitative MRI parameters in the vicinity of substantia nigra without any a priori delineation. This approach uses an alternative method of statistical, voxel-based analysis of quantitative maps and was tested on 18 patients and 15 healthy controls using a well-established, quantitative free water mapping protocol. It was possible to reveal the topology and the location of pathological changes in the substantia nigra and its vicinity. Moreover, a decrease in free water content, T1 and T2* in the vicinity of substantia nigra was indicated in the Parkinson’s disease patients compared to the healthy controls. These findings reflect a disruption of grey matter and iron accumulation, which is known to lead to neurodegeneration. Consequently, the proposed method demonstrates an increased sensitivity for the detection of pathological changes—even in small regions—and can facilitate disease monitoring via quantitative MR parameters

Maternal - Fetal Interaction: An Insight through the Stable Isotope Fractionation Prism

Aims: To compare carbon and nitrogen isotopic composition of maternal and fetal organs. Study Design: Cross-sectional study. Place and Duration of Study: Biology Department of Lomonosov Moscow State University; Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences; 2008 – 2011. Methodology: Mass spectrometric measurements of carbon and nitrogen isotopic ratios of corresponding maternal and fetal organs of gravid mice fed a monotonous diet. Results: Both the maternal and fetal organs (kidney, muscles, liver, myocardium, brain) of mice at the last term of gestation are enriched in 13C and 15N relative to food consumed. Isotopic composition of organs strongly depends on the number of bearing fetuses. The increase of fetuses’ number results in coordinated 13C depletion and 15N enrichment in both the maternal and fetal organs. Conclusion: The alteration of the δ13C and δ15N values reflects solely the metabolic restructuring during a pregnancy, since mice were fed the monotonous diet prior to conception and during gestation. Isotopic alterations develop as a reaction to the nutritional stress of the maternal organism under the trophic demands of fetuses. The protein replenishment is the most probable cause of isotope ratio changes. Under the controlled experimental condition the stable Isotope composition of biogenic elements can be used as integral indicators of metabolic efforts of the particular organismic structures. The predictive role of such integral indicators consists at least in limitation of possible biochemical conversions underlying the metabolism change