Effects of Quasi-Static Aberrations in Faint Companion Searches

We present the first results obtained at CFHT with the TRIDENT infrared camera, dedicated to the detection of faint companions close to bright nearby stars. The camera's main feature is the acquisition of three simultaneous images in three wavelengths (simultaneous differential imaging) across the methane absorption bandhead at 1.6 micron, that enables a precise subtraction of the primary star PSF while keeping the companion signal. The main limitation is non-common path aberrations between the three optical paths that slightly decorrelate the PSFs. Two types of PSF calibrations are combined with the differential simultaneous imaging technique to further attenuate the PSF: reference star subtraction and instrument rotation to smooth aberrations. It is shown that a faint companion with a DeltaH of 10 magnitudes would be detected at 0.5 arcsec from the primary.Comment: 12 pages, 10 figures, to appear in Astronomy with High Contrast Imaging, EAS Publications Serie

Exploring Clinical Risk Factors for Breast Cancer among American Indian Women

Objective: Very little is known about the breast cancer risk profile among American Indian women. Previous research shows that the proportion of American Indian/Alaska Native women with baseline characteristics (commonly known breast cancer risk factors) differs from other ethnicities. This retrospective case control study was designed to the explore the association of these factors among American Indian women with and without breast cancer. Methods: Cases and controls were retrospectively selected from the medical records of American Indian women who obtained their health care from Quentin N. Burdick Memorial Health Care Facility (IHS) in Belcourt, ND. For each woman with breast cancer (n=141), two controls were selected when possible (n=278). Risk factors examined included woman’s age, age at first live birth, age of menarche, the number of previous benign breast biopsies, the total number of first-degree relatives with breast cancer, body mass index and parity. Odds ratios and 95% confidence intervals were calculated using logistic regression. Results: Many of the associations found among American Indian women who obtained their health care from Quentin N. Burdick Memorial Health Care Facility (IHS) in Belcourt, ND, between risk factors commonly identified in other populations and breast cancer were weakly positive. Nulliparity was the only risk factor to consistently show a positive significant association (OR = 2.87, 95% CI 1.16-.7.12). Conclusion: Disparities in breast cancer incidence, mortality and screening among Northern Plains American Indian emphasize the need to better understand the risk factors associated with breast cancer in this population. Based on the results of this study, the value of current risk prediction models in American Indian communities is uncertain and clinicians should be cautious in using these models to inform American Indian patients of their risk for breast cancer

Interpretation of the transpulmonary thermodilution curve in the presence of a left-to-right shunt

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First-principles study of illite-smectite and implications for clay mineral systems

Illite-smectite interstratified clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons(1), rock cementation(2), evolution of porewater chemistry during diagenesis(3) and the development of pore pressure(4). But, despite the importance of these clays, their structures are controversial. Two competing models exist, each with profoundly different consequences for the understanding of diagenetic processes: model A views such interstratified clays as a stacking of layers identical to endmember illite and smectite layers, implying discrete and independently formed units (fundamental particles)(5), whereas model B views the clays as composed of crystallites with a unique structure that maintains coherency over much greater distances, in line with local charge balance about interlayers(6). Here we use first-principles density-functional theory to explore the energetics and structures of these two models for an illite-smectite interstratified clay mineral with a ratio of 1:1 and a Reichweite parameter of 1. We find that the total energy of model B is 2.3 kJ atom(-1) mol(-1) lower than that of model A, and that this energy difference can be traced to structural distortions in model A due to local charge imbalance. The greater stability of model B requires re-evaluation of the evolution of the smectite-to-illite sequence of clay minerals, including the nature of coexisting species, stability relations, growth mechanisms and the model of fundamental particles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62760/1/nature01155.pd

Classi in rete. Un modello internazionale per innovare la didattica nelle piccole scuole

L’apprendimento a distanza rappresenta un grande potenziale per le piccole scuole,richiede però di ripensare la forme scolaireper queste ultime. Indire, in collaborazione con il Centre scolaire du Fleuve et des Lacs(Ministère de l’éducation et de l’enseignement supérieur du Québec), la Italian University Line (IUL), l’Ufficio Scolastico Regionale (USR) Abruzzo e un esperto dell’Università della Valle d’Aosta, ha promosso un intervento di formazione e sperimentazione per aiutare i docenti delle piccole scuole ad attuare il modello “Classi in rete”sviluppato dall’École éloignée en Réseau(Allaire et al.,2009) e basato sull’approccio teorico delle Knowledge Building Communities

Changes in antigen-specific T cell number and function during oral desensitization in cow’s milk allergy enabled with omalizumab

Food allergy is a major public health problem for which there is no effective treatment. We examined the immunological changes that occurred in a group of children with significant cow’s milk allergy undergoing a novel and rapid high dose oral desensitization protocol enabled by treatment with omalizumab (anti-IgE mAb). Within a week of treatment, the CD4+ T cell response to milk was nearly eliminated, suggesting anergy in, or deletion of, milk-specific CD4+ T cells. Over the following three months while the subjects remained on high doses of daily oral milk, the CD4+ T cell response returned, characterized by a shift from IL-4 to IFN-γ production. Desensitization was also associated with reduction in milk-specific IgE and a 15-fold increase in milk-specific IgG4. These studies suggest that high dose oral allergen desensitization may be associated with deletion of allergen-specific T cells, without the apparent development of allergen-specific Foxp3+ regulatory T cells

Anatomy of a microearthquake sequence on an active normal fault

The analysis of similar earthquakes, such as events in a seismic sequence, is an effective tool with which to monitor and study source processes and to understand the mechanical and dynamic states of active fault systems. We are observing seismicity that is primarily concentrated in very limited regions along the 1980 Irpinia earthquake fault zone in Southern Italy, which is a complex system characterised by extensional stress regime. These zones of weakness produce repeated earthquakes and swarm-like microearthquake sequences, which are concentrated in a few specific zones of the fault system. In this study, we focused on a sequence that occurred along the main fault segment of the 1980 Irpinia earthquake to understand its characteristics and its relation to the loading-unloading mechanisms of the fault system

Making Sense of Family Deaths in Urban Senegal: Diversities, Contexts, and Comparisons

Despite calls for cross-cultural research, Minority world perspectives still dominate death and bereavement studies, emphasizing individualized emotions and neglecting contextual diversities. In research concerned with contemporary African societies, on the other hand, death and loss are generally subsumed within concerns about AIDS or poverty, with little attention paid to the emotional and personal significance of a death. Here, we draw on interactionist sociology to present major themes from a qualitative study of family deaths in urban Senegal, theoretically framed through the duality of meanings-in-context. Such themes included family and community as support and motivation; religious beliefs and practices as frameworks for solace and (regulatory) meaning; and material circumstances as these are intrinsically bound up with emotions. Although we identify the experience of (embodied, emotional) pain as a common response across Minority and Majority worlds, we also explore significant divergencies, varying according to localized contexts and broader power dynamics