(Z)-N-(2-Iodophenyl)-4-nitrobenzimidoyl cyanide

In the title molecule, C14H8IN3O2, the cyanide group is anti to the iodide substituent of the adjacent benzene ring. The central segment is essentially planar (r.m.s deviation = 0.0341 A ° ) and it is twisted away from the iodide- and nitro-substituted benzene rings by 69.02 (9) and 15.83 (16), respectively. In the crystal, molecules are linked by weak C—H N interactions, leading to C(8) chains along [010]

The Origin of Amerindians and the Peopling of the Americas According to HLA Genes: Admixture with Asian and Pacific People

The classical three-waves theory of American peopling through Beringia was based on a mixed anthropological and linguistic methodology. The use of mtDNA, Y chromosome and other DNA markers offers different results according to the different markers and methodologies chosen by different authors. At present, the peopling of Americas remains uncertain, regarding: time of population, number of peopling waves and place of peopling entrance among other related issues. In the present review, we have gathered most available HLA data already obtained about First Native American populations, which raise some doubts about the classical three waves of American peopling hypothesis. In summary, our conclusions are: 1) North West Canadian Athabaskans have had gene flow with: a) close neighboring populations, b) Amerindians, c) Pacific Islanders including East Australians and d) Siberians; 2) Beringia was probably not the only entrance of people to America: Pacific Ocean boat trips may have contributed to the HLA genetic American profile (or the opposite could also be true); 3) Amerindians entrance to America may have been different to that of Athabaskans and Eskimos and Amerindians may have been in their lands long before Athabaskans and Eskimos because they present and altogether different set of HLA-DRB1 allele frequencies; 4) Amerindians show very few “particular alleles”, almost all are shared with other Amerindians, Athabaskans and Pacific Islanders, including East Australians and Siberians; 5) Our results do not support the three waves model of American peopling, but another model where the people entrance is not only Beringia, but also Pacific Coast. Reverse migration (America to Asia) is not discarded and different movements of people in either direction in different times are supported by the Athabaskan population admixture with Asian-Pacific population and with Amerindians, 6) HLA variability is more common than allele veriability in Amerindians. Finally, it is shown that gene genealogy analises should be completed with allele frequency analyses in population relatednes and migrations studies

Mechanical properties of freely suspended atomically thin dielectric layers of mica

We have studied the elastic deformation of freely suspended atomically thin sheets of muscovite mica, a widely used electrical insulator in its bulk form. Using an atomic force microscope, we carried out bending test experiments to determine the Young's modulus and the initial pre-tension of mica nanosheets with thicknesses ranging from 14 layers down to just one bilayer. We found that their Young's modulus is high (190 GPa), in agreement with the bulk value, which indicates that the exfoliation procedure employed to fabricate these nanolayers does not introduce a noticeable amount of defects. Additionally, ultrathin mica shows low pre-strain and can withstand reversible deformations up to tens of nanometers without breaking. The low pre-tension and high Young's modulus and breaking force found in these ultrathin mica layers demonstrates their prospective use as a complement for graphene in applications requiring flexible insulating materials or as reinforcement in nanocomposites.Comment: 9 pages, 5 figures, selected as cover of Nano Research, Volume 5, Number 8 (2012

Structural Brain Network Reorganization and Social Cognition Related to Adverse Perinatal Condition from Infancy to Early Adolescence.

Adverse conditions during fetal life have been associated to both structural and functional changes in neurodevelopment from the neonatal period to adolescence. In this study, connectomics was used to assess the evolution of brain networks from infancy to early adolescence. Brain network reorganization over time in subjects who had suffered adverse perinatal conditions is characterized and related to neurodevelopment and cognition. Three cohorts of prematurely born infants and children (between 28 and 35 weeks of gestational age), including individuals with a birth weight appropriated for gestational age and with intrauterine growth restriction (IUGR), were evaluated at 1, 6, and 10 years of age, respectively. A common developmental trajectory of brain networks was identified in both control and IUGR groups: network efficiencies of the fractional anisotropy (FA)-weighted and normalized connectomes increase with age, which can be related to maturation and myelination of fiber connections while the number of connections decreases, which can be associated to an axonal pruning process and reorganization. Comparing subjects with or without IUGR, a similar pattern of network differences between groups was observed in the three developmental stages, mainly characterized by IUGR group having reduced brain network efficiencies in binary and FA-weighted connectomes and increased efficiencies in the connectome normalized by its total connection strength (FA). Associations between brain networks and neurobehavioral impairments were also evaluated showing a relationship between different network metrics and specific social cognition-related scores, as well as a higher risk of inattention/hyperactivity and/or executive functional disorders in IUGR children

Mechanical properties of freely suspended semiconducting graphene-like layers based on MoS2

We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy. We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope. The Young's modulus and the initial pre-tension of the nanosheets are determined by performing a nanoscopic version of a bending test experiment. MoS2 sheets show high elasticity and an extremely high Young's modulus (0.30 TPa, 50% larger than steel). These results make them a potential alternative to graphene in applications requiring flexible semiconductor materials

Television viewing and its association with overweight in Colombian children: results from the 2005 National Nutrition Survey: A cross sectional study

<p>Abstract</p> <p>Background</p> <p>There has been an ongoing discussion about the relationship between time spent watching television and childhood obesity. This debate has special relevance in the Latin American region were the globalization process has increased the availability of screen-based entertainment at home. The aim of this study is to examine the association between television viewing and weight status in Colombian children.</p> <p>Methods</p> <p>This cross sectional investigation included children aged 5 to12 yrs from the National Nutrition Survey in Colombia (ENSIN 2005). Weight and height were measured in 11,137 children in order to calculate body mass index. Overweight was defined by international standards. Time spent viewing television was determined for these children through parental reports. Multiple logistic regression analyses were conducted for different subgroups and adjusted for potential confounders in order to study the association between television viewing and weight status in this population.</p> <p>Results</p> <p>Among the surveyed children, 41.5% viewed television less than two hours/day; 36.8% between two and 3.9 hours/day and 21.7% four or more hours/day. The prevalence of overweight (obesity inclusive) in this population was 11.1%. Children who were classified as excessive television viewers (between two and 3.9 hours/day or 4 or more hours/day) were more likely to be overweight (OR: 1.44 95% CI: 1.41–1.47 and OR: 1.32 95% CI: 1.30–1.34, respectively) than children who reported to watch television less than 2 hours/day. Stratified analyses by age, gender and urbanization levels showed similar results.</p> <p>Conclusion</p> <p>Television viewing was positively associated with the presence of overweight in Colombian children. A positive association between urbanization level and television viewing was detected. Considering that the majority of Colombian children lives in densely populated cities and appear to engage in excessive television viewing these findings are of public health relevance for the prevention of childhood obesity.</p

Evidence Against the Sciama Model of Radiative Decay of Massive Neutrinos

We report on spectral observations of the night sky in the band around 900 angstroms where the emission line in the Sciama model of radiatively decaying massive neutrinos would be present. The data were obtained with a high resolution, high sensitivity spectrometer flown on the Spanish MINISAT satellite. The observed emission is far less intense than that expected in the Sciama model.Comment: 9 pages, accepted to Ap