A spectral study of gamma-ray emitting AGN

In this paper we present a statistical analysis of the gamma-ray spectra of flat-spectrum radio quasars (FSRQ) compared to those of BL Lacs. The average spectra and possible systematic deviations from power-law behaviour are investigated by summing up the intensity and the power-law fit statistic for both classes of objects. We also compare the time-averaged spectrum to that at the time of gamma-ray outbursts. The spectrum of the average AGN is softer than that of the extragalactic gamma-ray background. It may be that BL Lacs, which on average have a harder spectrum than FSRQs, make up the bulk of the extragalactic background. We also find apparent cut-offs at both low and high energies in the spectra of FSRQs at the time of gamma-ray outbursts. While the cut-off at high energies may have something to do with opacity, the cut-off at low energies may be taken as indication that the gamma-ray emission of FSRQs is not a one component spectrum.Comment: 8 pages, accepted for publication in A&

An interface configuration experiment on USML-1

Experiments were carried out for exotic'' rotationally symmetric containers aboard the first NASA United States Microgravity Laboratory Space Shuttle flight (USML-1). The containers have the property that they admit an entire continuum of distinct equilibrium rotationally-symmetric capillary free-surfaces for a given liquid volume and contact angle. It was found, after the containers were filled in orbit, that an initial equilibrium interface from the symmetric continuum reoriented, when perturbed, to a stable interface that was not rotationally symmetric, as predicted by the mathematical theory

Endogenous sex hormone levels and breast cancer risk

Sex‐steroid hormones are a major determinant of the risk of breast cancer. We evaluated the relationship between obesity and endogenous estrogen levels in 79 healthy, postmenopausal women. Thirty‐nine of the women were siblings of patients with postmenopausal‐onset breast cancer; the remaining women were age matched (± 10 yr) controls. Our hypothesis was that the siblings of the breast cancer patients would weigh more and that this excess weight would lead to higher serum estrone levels. The choice of unaffected family members of breast cancer patients reduces the concern that results may have been influenced by the cancer rather than antecedent to its development. Our findings demonstrated a statistically significant excess estrone level in the siblings compared to the controls (58.9 vs 47.8 pg/ml, P=0.005). The siblings weighed 4.3 kg more than the controls. Matched pairs analysis (sibling—control), adjusting for weight, also showed significant differences in serum estrone levels. These differences were observed despite comparability in dietary intake, medication use, and personal medical history. These findings represent the first time that higher estrogen levels have been measured in siblings of postmenopausal breast cancer patients. This observation may represent an important link in our understanding of the relationship between genetic and environmental risk factors of breast cancer. One approach to subsequent genetic studies of breast cancer may be to focus on the possible biological determinants such as sex‐steroid hormone level receptors, oncogenes, and gene products and not on the “familial aggregation” of breast cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/101821/1/1370040402_ftp.pd

A new scale measuring adaptive perceived control for people with Parkinson's: initial construction and further validation

Introduction Perceived control is an important concept in understanding adjustment to chronic conditions such as Parkinson’s. While generic measures have been used to measure the construct in Parkinson’s, no Parkinson’s-specific scale currently exists. This study outlines the initial development and further validation of a free-to-use scale, the Parkinson’s UK Scale of Perceived Control (PUKSoPC). Method Focus groups were used to create items for the new scale. Potential items were then subject to screening for readability and coherence by people affected by the condition. This left 49 items that were then completed, along with other measures, by 231 people with Parkinson’s. Exploratory factor analysis then created a 15-item scale with five distinct subscales. This initial structure was then further tested using confirmatory factor analysis with 2032 people with Parkinson’s. Structural equation modelling confirmed the acceptability of the total scale and subscale structures. Results The final scale is concluded to be a psychometrically robust measure of perceived control. It has good face validity, evidence of convergent and criterion (concurrent and divergent) validity, good test-retest reliability and is internally coherent, with a demonstrably solid factor structure. While further testing would be useful to assess the scale’s predictive ability, it is currently considered robust enough for more widespread use. Conclusion The PUKSoPC is an appropriate scale to provide a more comprehensive measure of perceived control. It is preferable to single item, non-validated measures and can provide evidence of perceptions of control across a number of domains important in the measurement of the construct

The development of a web- and a print-based decision aid for prostate cancer screening

Background Whether early detection and treatment of prostate cancer (PCa) will reduce disease-related mortality remains uncertain. As a result, tools are needed to facilitate informed decision making. While there have been several decision aids (DAs) developed and tested, very few have included an exercise to help men clarify their values and preferences about PCa screening. Further, only one DA has utilized an interactive web-based format, which allows for an expansion and customization of the material. We describe the development of two DAs, a booklet and an interactive website, each with a values clarification component and designed for use in diverse settings. Methods We conducted two feasibility studies to assess men\u27s (45-70 years) Internet access and their willingness to use a web- vs. a print-based tool. The booklet was adapted from two previous versions evaluated in randomized controlled trials (RCTs) and the website was created to closely match the content of the revised booklet. Usability testing was conducted to obtain feedback regarding draft versions of the materials. The tools were also reviewed by a plain language expert and the interdisciplinary research team. Feedback on the content and presentation led to iterative modifications of the tools. Results The feasibility studies confirmed that the Internet was a viable medium, as the majority of men used a computer, had access to the Internet, and Internet use increased over time. Feedback from the usability testing on the length, presentation, and content of the materials was incorporated into the final versions of the booklet and website. Both the feasibility studies and the usability testing highlighted the need to address men\u27s informed decision making regarding screening. Conclusions Informed decision making for PCa screening is crucial at present and may be important for some time, particularly if a definitive recommendation either for or against screening does not emerge from ongoing prostate cancer screening trials. We have detailed our efforts at developing print- and web-based DAs to assist men in determining how to best meet their PCa screening preferences. Following completion of our ongoing RCT designed to test these materials, our goal will be to develop a dissemination project for the more effective tool