99 research outputs found

    On the ability of spectroscopic SZ effect measurements to determine the temperature structure of galaxy clusters

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    (abridged) We explore in this paper the ability of spatially resolved spectroscopic measurements of the SZ effect (SZE) to determine the temperature profile of galaxy clusters. We derive a general formalism for the thermal SZE in galaxy clusters with a non-uniform temperature profile that can be applied to both cool-core clusters and non-cool core cluster with an isothermal or non-isothermal temperature structure. We derive an inversion technique through which the electron distribution function can be extracted from spectroscopic SZE observations over a wide frequency range. We study the fitting procedure to extract the cluster temperature from a set of simulated spatially resolved spectroscopic SZE observations in different bands of the spectrum, from 100 to 450 GHz. The results of our analysis for three different cluster prototypes (A2199 with a low-temperature cool core, Perseus with a relatively high-temperature cool core, Ophiuchus with an isothermal temperature distribution) provide both the required precision of the SZE observations and the optimal frequency bands for a determination of the cluster temperature similar or better than that obtainable from X-ray observations. The precision of SZE-derived temperature is also discussed for the outer regions of clusters. We also study the possibility to extract, from our method, the parameters characterizing the non-thermal SZE spectrum of the relativistic plasma contained in the lobes of radio galaxies as well as the spectrum of relativistic electrons co-spatially distributed with the thermal plasma in clusters with non-thermal phenomena. We find that the next generation SZE experiments with spectroscopic capabilities can provide precise temperature distribution measurements (...)Comment: Submitted to Astronomy & Astrophysic

    Prognostic Factors in 77 Curative Chest Wall Resections for Isolated Breast Cancer Recurrence

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    Background: Full-thickness chest wall resection (CWR) is the preferred treatment for breast cancer (BC) patients with extensive isolated locoregional recurrence. It remains a challenge to select patients that will benefit most from this treatment. The aim of this study was to define prognostic factors in patients who undergo CWR with curative intent. Methods: BC patients who underwent a CWR with curative intent for recurrence of disease between 1986 and 2006 were included in this retrospective study. Twenty-two factors were studied in a univariate analyses, and multivariate stepwise Cox regression analyses was performed. Results: Seventy-seven patients were included in this study. The 5-year overall survival was 25%. There was one postoperative death. Univariate analyses showed that three prognostic factors were significantly correlated with OS and disease-free survival: (1) interval between primary treatment and CWR (P = .02 and .004, respectively), (2) chemotherapy for recurrence (P = .05 and .05, respectively), and (3) resection specimen smaller than 150 cm2(P = .03 and .009, respectively). An interval lasting >10 years between primary treatment and CWR remained statistically significantly correlated with better overall survival and disease-free survival after multivariate analyses. Conclusions: CWR is a safe treatment in patients who have isolated extensive BC recurrence. The best survival outcome was seen in patients after a disease-free interval of >10 years. Existing data show that adjuvant radiotherapy and adjuvant hormone therapy for estrogen-positive tumors improves overall survival. Neoadjuvant chemotherapy may be considered in individual patients

    Communicating Phylogeny: Evolutionary Tree Diagrams in Museums

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    Tree of life diagrams are graphic representations of phylogeny—the evolutionary history and relationships of lineages—and as such these graphics have the potential to convey key evolutionary ideas and principles to a variety of audiences. Museums play a significant role in teaching about evolution to the public, and tree graphics form a common element in many exhibits even though little is known about their impact on visitor understanding. How phylogenies are depicted and used in informal science settings impacts their accessibility and effectiveness in communicating about evolution to visitors. In this paper, we summarize the analysis of 185 tree of life graphics collected from museum exhibits at 52 institutions and highlight some potential implications of how trees are presented that may support or hinder visitors’ understanding about evolution. While further work is needed, existing learning research suggests that common elements among the diversity of museum trees such as the inclusion of anagenesis and absence of time and shared characters might represent potential barriers to visitor understanding

    Health Disparities Between Appalachian and Non-Appalachian Counties in Virginia USA

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    The examination of health disparities among people within Appalachian counties compared to people living in other counties is needed to find ways to strategically target improvements in community health in the United States of America (USA). Methods: A telephone survey of a random sample of adults living in households within communities of all counties of the state of Virginia (VA) in the USA was conducted. Findings: Health status was poorer among those in communities within Appalachian counties in VA and health insurance did not make a difference. Health perception was significantly worse in residents within communities in Appalachian counties compared to non-Appalachian community residents (30.5 vs. 17.4% rated their health status as poor/fair), and was worse even among those with no chronic diseases. Within communities in Appalachian counties, black residents report significantly better health perception than do white residents. Conclusion: Residents living in communities in Appalachian counties in VA are not receiving adequate health care, even among those with health insurance. More research with a larger ethnic minority sample is needed to investigate the racial/ethnic disparities in self-reported health and health care utilization within communities

    On the relation between action selection and movement control in 5- to 9-month-old infants

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    Although 5-month-old infants select action modes that are adaptive to the size of the object (i.e., one- or two-handed reaching), it has largely remained unclear whether infants of this age control the ensuing movement to the size of the object (i.e., scaling of the aperture between hands). We examined 5-, 7-, and 9-month-olds’ reaching behaviors to gain more insight into the developmental changes occurring in the visual guidance of action mode selection and movement control, and the relationship between these processes. Infants were presented with a small set of objects (i.e., 2, 3, 7, and 8 cm) and a large set of objects (i.e., 6, 9, 12, and 15 cm). For the first set of objects, it was found that the infants more often performed two-handed reaches for the larger objects based on visual information alone (i.e., before making contact with the object), thus showing adaptive action mode selection relative to object size. Kinematical analyses of the two-handed reaches for the second set of objects revealed that inter-trial variance in aperture between the hands decreased with the approach toward the object, indicating that infants’ reaching is constrained by the object. Subsequent analysis showed that between hand aperture scaled to object size, indicating that visual control of the movement is adjusted to object size in infants as young as 5 months. Individual analyses indicated that the two processes were not dependent and followed distinct developmental trajectories. That is, adaptive selection of an action mode was not a prerequisite for appropriate aperture scaling, and vice versa. These findings are consistent with the idea of two separate and independent visual systems (Milner and Goodale in Neuropsychologia 46:774–785, 2008) during early infancy

    B Cell Activating Factor (BAFF) and T Cells Cooperate to Breach B Cell Tolerance in Lupus-Prone New Zealand Black (NZB) Mice

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    The presence of autoantibodies in New Zealand Black (NZB) mice suggests a B cell tolerance defect however the nature of this defect is unknown. To determine whether defects in B cell anergy contribute to the autoimmune phenotype in NZB mice, soluble hen egg lysozyme (sHEL) and anti-HEL Ig transgenes were bred onto the NZB background to generate double transgenic (dTg) mice. NZB dTg mice had elevated levels of anti-HEL antibodies, despite apparently normal B cell functional anergy in-vitro. NZB dTg B cells also demonstrated increased survival and abnormal entry into the follicular compartment following transfer into sHEL mice. Since this process is dependent on BAFF, BAFF serum and mRNA levels were assessed and were found to be significantly elevated in NZB dTg mice. Treatment of NZB sHEL recipient mice with TACI-Ig reduced NZB dTg B cell survival following adoptive transfer, confirming the role of BAFF in this process. Although NZB mice had modestly elevated BAFF, the enhanced NZB B cell survival response appeared to result from an altered response to BAFF. In contrast, T cell blockade had a minimal effect on B cell survival, but inhibited anti-HEL antibody production. The findings suggest that the modest BAFF elevations in NZB mice are sufficient to perturb B cell tolerance, particularly when acting in concert with B cell functional abnormalities and T cell help
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