Micro Computed Tomography and Micro X-Ray Fluorescence and Tools for the Curation and Scientific Study of Apollo Samples

No abstract availabl

Generating Excitement and Increasing Awaressness of NASA Planetary Science and Astromaterials Assets

Students, educators, the public, and the scientific community are so often inspired by NASA science and exploration. Millions have joined NASA during live mission event broadcasts and also follow NASA on social media. Exploration of worlds in our solar system enable the scientific community to obtain and analyze data that provide clues to better understand the history and evolution of our solar system. Missions that collect and return samples to Earth from a target solar system body provide scientists with samples they can research and analyze in their laboratories. For those who are not planetary scientists, they may not understand the significance of these samples and/or the importance of sample return missions. The Astromaterials Research and Exploration Science (ARES) Science Engagement team, through work supported by NASAs Science Mission Directorate (SMD) Science Education Cooperative Agreement Notice NNH15ZDA004C, provides access to samples from NASAs Astromaterials Collections through NASA sponsored exhibits at educator and scientific conferences, NASA relevant public outreach events, and collaborations with other Science Activation Teams supported by the SMD Cooperative Agreement Notice. The goal of this work is to generate excitement while enhancing knowledge and awareness of NASAs unique assets, thus highlighting NASA planetary science and exploration

Compostos fenólicos e atividade antioxidante de grãos de arroz de pericarpo vermelho e de pericarpo preto.

Objetivou-se, com o presente estudo, avaliar o teor de compostos fenólicos livres e complexados e a atividade antioxidante pelo método ABTS, tanto da fração de fenólicos livres como de fenólicos complexados, de grãos de duas cultivares de arroz de pericarpo preto (IAC 600 e SCS 120) e de duas cultivares de arroz de pericarpo vermelho (BRS 902 e SCS 119).Os grãos de arroz foram colhidos no campo experimental da Embrapa Arroz e Feijão, em Santo Antônio de Goiás, Goiás, Brasil

Solid State Microdosimetry With Heavy Ions for Space Applications

This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions

Microdosimetry simulations of solar protons within a spacecraft

The microdosimetric spectra derived by silicon microdosimeter in a proton radiation field traversing heterogeneous structures were simulated using the GEANT4 toolkit

Exact eigenstate analysis of finite-frequency conductivity in graphene

We employ the exact eigenstate basis formalism to study electrical conductivity in graphene, in the presence of short-range diagonal disorder and inter-valley scattering. We find that for disorder strength, $W \ge$ 5, the density of states is flat. We, then, make connection, using the MRG approach, with the work of Abrahams \textit{et al.} and find a very good agreement for disorder strength, $W$ = 5. For low disorder strength, $W$ = 2, we plot the energy-resolved current matrix elements squared for different locations of the Fermi energy from the band centre. We find that the states close to the band centre are more extended and falls of nearly as $1/E_l^{2}$ as we move away from the band centre. Further studies of current matrix elements versus disorder strength suggests a cross-over from weakly localized to a very weakly localized system. We calculate conductivity using Kubo Greenwood formula and show that, for low disorder strength, conductivity is in a good qualitative agreement with the experiments, even for the on-site disorder. The intensity plots of the eigenstates also reveal clear signatures of puddle formation for very small carrier concentration. We also make comparison with square lattice and find that graphene is more easily localized when subject to disorder.Comment: 11 pages,15 figure

Local moment formation in zinc doped cuprates

We suggest that when zinc is substituted for copper in the copper oxide planes of high $T_{c}$ superconductors, it does not necessarily have a valency of 2+. Rather, the valency of a zinc impurity should be determined by its surrounding medium. In order to study this hypothesis, we examine the effect of static impurities inducing diagonal disorder within a one band Hubbard model coupled to a localised state. We use this model to discuss the physics of zinc doping in the cuprates. Specifically, we discuss the formation of local moments near impurity sites and the modification of the transverse spin susceptibility in the antiferromagnetic state.Comment: 7 pages RevTex, includes 4 figure

Evolution of predator dispersal in relation to spatio-temporal prey dynamics : how not to get stuck in the wrong place!

Peer reviewedPublisher PD

Increased S-nitrosylation and proteasomal degradation of caspase-3 during infection contribute to the persistence of adherent invasive escherichia coli (AIEC) in immune cells

Adherent invasive Escherichia coli (AIEC) have been implicated as a causative agent of Crohn's disease (CD) due to their isolation from the intestines of CD sufferers and their ability to persist in macrophages inducing granulomas. The rapid intracellular multiplication of AIEC sets it apart from other enteric pathogens such as Salmonella Typhimurium which after limited replication induce programmed cell death (PCD). Understanding the response of infected cells to the increased AIEC bacterial load and associated metabolic stress may offer insights into AIEC pathogenesis and its association with CD. Here we show that AIEC persistence within macrophages and dendritic cells is facilitated by increased proteasomal degradation of caspase-3. In addition S-nitrosylation of pro- and active forms of caspase-3, which can inhibit the enzymes activity, is increased in AIEC infected macrophages. This S-nitrosylated caspase-3 was seen to accumulate upon inhibition of the proteasome indicating an additional role for S-nitrosylation in inducing caspase-3 degradation in a manner independent of ubiquitination. In addition to the autophagic genetic defects that are linked to CD, this delay in apoptosis mediated in AIEC infected cells through increased degradation of caspase-3, may be an essential factor in its prolonged persistence in CD patients

A new world typology of cities and systems of cities

The chapter proposes an overview of global urbanization since 1950, relying on the structural and dynamic principles of the evolutionary theory of urban systems and on the observations of some of the major financial linkages connecting cities. We analyze first an overview of the state of urbanization at the world scale using statistics collected and provided for all 195 nation-states of the United Nations. We then examine the extent to which the income level and human development index of countries are correlated with the urbanization rates. Trajectories of cities underline the booming cities including many Asiatic and African cities opposed to the relative declining cities. The total weight of emerging metropolises mostly located in Southern countries passed the total population of the other groups of relatively declining cities between 1980 and 2010. It is highly critical for the urban future that the large majority of urban citizens of the world (more than 60%) will be living in these emerging cities in 2030. It will require finding adapted ways to manage urban growth and ecological transition in these developing systems. This global approach finally leads to the partition of the world we used in the book to analyze more precisely the evolution of individual national or continental urban systems