M31's Heavy Element Distribution and Outer Disk

Hubble Space Telescope imaging of 11 fields in M31 were reduced to color-magnitude diagrams. The fields were chosen to sample all galactocentric radii to 50 kpc. Assuming that the bulk of the sampled stellar populations are older than a few Gyr, the colors of the red giants map to an abundance distribution with errors of order 0.1 dex in abundance. The radially sampled abundance distributions are all about the same width, but show a mild abundance gradient that flattens outside ~20 kpc. The various distributions were weighted and summed with the aid of new surface brightness profile fits to obtain an abundance distribution representative of the entirety of M31. M31 is a system near chemical maturity. This ``observed closed box'' is compared to analytical closed box models. M31 suffers from a lack of metal-poor stars and metal-rich stars relative to the simplest closed-box model in the same way as the solar neighborhood.Comparing to several simple chemical evolution models, neither complete mixing of gas at all times nor zero mixing, inhomogeneous models give the most convincing match to the data. As noted elsewhere, the outer disk of M31 is a factor of ten more metal-rich than the Milky Way halo, ten times more metal-rich than the dwarf spheroidals cospatial with it, and more metal-rich than most of the globular clusters at the same galactocentric radius. Difficulties of interpretation are greatly eased if we posit that the M31 disk dominates over the halo at all radii out to 50 kpc. In fact, scaling from current density models of the Milky Way, one should not expect to see halo stars dominating over disk stars until beyond our 50 kpc limit. A corollary conclusion is that most published studies of the M31 "halo" are actually studies of its disk.Comment: 28 pages, 11 black-and-white figures, in press, Astrophysical Journa

Engineering Nano- and Microparticles to Tune Immunity

The immune system can be a cure or cause of disease, fulfilling a protective role in attacking cancer or pathogenic microbes but also causing tissue destruction in autoimmune disorders. Thus, therapies aimed to amplify or suppress immune reactions are of great interest. However, the complex regulation of the immune system, coupled with the potential systemic side effects associated with traditional systemic drug therapies, has presented a major hurdle for the development of successful immunotherapies. Recent progress in the design of synthetic micro- and nano-particles that can target drugs, deliver imaging agents, or stimulate immune cells directly through their physical and chemical properties is leading to new approaches to deliver vaccines, promote immune responses against tumors, and suppress autoimmunity. In addition, novel strategies, such as the use of particle-laden immune cells as living targeting agents for drugs, are providing exciting new approaches for immunotherapy. This progress report describes recent advances in the design of micro- and nano-particles for immunotherapies and diagnostics.National Institutes of Health (U.S.) (AI095109)National Institutes of Health (U.S.) (CA140476)United States. Dept. of Defense (Contract W81XWH-10-1-0290)United States. Dept. of Defense (Contract W911NF-07-D-0004)Ragon Institute of MGH, MIT and Harvar

Tunable Porous Organic Crystals: Structural Scope and Adsorption Properties of Nanoporous Steroidal Ureas

Previous work has shown that certain steroidal bis-(N-phenyl)ureas, derived from cholic acid, form crystals in the P61 space group with unusually wide unidimensional pores. A key feature of the nanoporous steroidal urea (NPSU) structure is that groups at either end of the steroid are directed into the channels and may in principle be altered without disturbing the crystal packing. Herein we report an expanded study of this system, which increases the structural variety of NPSUs and also examines their inclusion properties. Nineteen new NPSU crystal structures are described, to add to the six which were previously reported. The materials show wide variations in channel size, shape, and chemical nature. Minimum pore diameters vary from ∼0 up to 13.1 Å, while some of the interior surfaces are markedly corrugated. Several variants possess functional groups positioned in the channels with potential to interact with guest molecules. Inclusion studies were performed using a relatively accessible tris-(N-phenyl)urea. Solvent removal was possible without crystal degradation, and gas adsorption could be demonstrated. Organic molecules ranging from simple aromatics (e.g., aniline and chlorobenzene) to the much larger squalene (Mw = 411) could be adsorbed from the liquid state, while several dyes were taken up from solutions in ether. Some dyes gave dichroic complexes, implying alignment of the chromophores in the NPSU channels. Notably, these complexes were formed by direct adsorption rather than cocrystallization, emphasizing the unusually robust nature of these organic molecular hosts

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

D' Annunzio en Grèce. Laus Vitae et la Croisière de 1895 d' après des documents inédits.

Preface.Appendix.Introduction.Dedication: Georges Hérelle & Guido BoggianiContent description: IndexIllustration: 17 (Maps ,Views ,antiquities ,)Pagination: PP5+180PVolumes: 1Text Genre:ProseIllustration: 17 (χάρτες ,τοπία ,αρχαιότητες ,

Gabriele D'Annunzio député

Tosi Guy. Gabriele D'Annunzio député. In: Revue du Nord, tome 36, n°142, Avril-juin 1954. Mélanges offerts à Louis Jacob à l'occasion de son 70e anniversaire. pp. 395-399

Modèle de zone cohésive viscoplastique dédié à la surfragmentation à haute température des céramiques nucléaires pressurisées

International audienceCe travail concerne le comportement d’un fragment de combustible irradié lors d’un hypothétique accident d’insertion de réactivité. Un nouveau modèle de zone cohésive a été développé en suivant l’approche micromécanique de Nkoumbou Kaptchouang et al. [1] et en utilisant le modèle visco-plastique endommageable pour l’UO2 de Salvo et al. [2]

Viscoplastic cohesive zone model dedicated to overfragmentation of pressurized nuclear ceramics at high temperature

International audienceThe material of the study is the uranium dioxide (UO 2) fuel used in pressurized water reactors (PWR). Under irradiation and steady state, this polycrystalline oxide exhibits intragranular and intergranular bubbles. Their sizes and their shapes vary according to the burn up and their location inside the fuel. They are saturated by fission gases. This work presents the modeling of the damage of a porous material and its overfragmentation under dynamic loading during RIA (Reactivity Initiated Accident, a fast thermal transient). This numerical study is performed on a fuel fragment generated under steady state of irradiation and submitted to RIA. A new cohesive zone model is developed following the micromechanical approach of Nkoumbou Kaptchouang and al. [1] and using the viscoplastic model for uranium dioxide of Salvo and al. [2]. This new cohesive model is temperature, porosity and strain-rate dependent. The traction-separation law enables to simulate the damage of the fuel until the creation of new cracks within the fuel fragment and their propagations

Modèle de zone cohésive viscoplastique dédié à la surfragmentation à haute température des céramiques nucléaires pressurisées

International audienceCe travail concerne le comportement d’un fragment de combustible irradié lors d’un hypothétique accident d’insertion de réactivité. Un nouveau modèle de zone cohésive a été développé en suivant l’approche micromécanique de Nkoumbou Kaptchouang et al. [1] et en utilisant le modèle visco-plastique endommageable pour l’UO2 de Salvo et al. [2]