641 research outputs found
Ball: Dynamics of the Patent System
A Review of Dynamics of the Patent System. Edited by William B. Ball
The Position of Sgr A at the Galactic Center
The absolute position of the compact radio source at the dynamical center of
the Galaxy, Sgr A, was known only to an accuracy of in spite of its
accurate location with respect to near-IR stellar sources to within 30
milliarcsecond (mas). To remedy this poor positional accuracy, we have selected
15 high-resolution, high-frequency VLA observations of Sgr A carried out in
the last 13 years and determined the weighted average position with the average
epoch 1992.4 to be at , [1950] =
29\dsec3076, , or
, [2000] = 40\dsec0383,
which agrees with earlier
published values to within the error bars of the earlier measurements.
An accurate absolute position of Sgr A can be useful for its identification
with sources at other wavelengths, particularly, in soft and hard X-rays with
implications for the models of a massive black hole at the Galactic center.Comment: 11 pages, one figure and one table. ApJL (in press
Shemel & Krasilovsky: This Business of Music
A Review of This Business of Music by Sidney Shemel and M. William Krasilovsk
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Thiotepa hyperpigmentation preceding epidermal necrosis: malignant intertrigo misdiagnosed as Stevens-Johnson syndrome-toxic epidermal necrolysis overlap
Thiotepa is a common alkylating agent known to precipitate cutaneous reactions consistent with toxic erythema of chemotherapy, including erythema and hyperpigmentation. Herein, we describe an atypical case of malignant intertrigo involving preferential erythema and desquamation not only of skin folds but also of occluded areas after thiotepa-based conditioning. The diagnosis was complicated by concurrent stomatitis and oral petechiae in the setting of autologous stem cell transplant 11 days prior for diffuse large B-cell lymphoma. Histopathological examination from two cutaneous sites demonstrated epidermal dysmaturation and eccrine gland necrosis consistent with thiotepa-induced desquamation and not Stevens-Johnson syndrome or graft-versus-host-disease. Malignant intertrigo can present with extensive cutaneous involvement, as evidenced by our patient who had 25% body surface area affected. Mucosal involvement is common with most chemotherapeutic regimens and its presence should not deter the astute clinician from consideration of a diagnosis of toxic erythema of chemotherapy. No further interventions were needed and the patient healed spontaneously
Stressors and resilience are associated with well-being in young adult college students
Objective: The purposes were to describe stressors and resilience behaviors of college students and examine the relationships among stressors, resilience, and well-being. Hypothesis: Resilience will modify the relationship between stressors and well-being. Participants: The sample included 1,010 college students, ages 18–26, from an urban Midwestern university. Methods: A secondary analysis of cross-sectional data from an anonymous survey was conducted using multiple regression and simple slopes analysis. Results: Resilience did not modify the relationship between stressors and well-being. Stressors (β = −.44, p \u3c .0001) and resilience (β = .33, p \u3c .0001) accounted for 42% of the variance in well-being (adjusted R2 = .42, F2,999 = 365.98, p \u3c .0001). The most frequently endorsed stressors were sleep problems, anxiety, and relationships. Conclusions: Stressors and resilience warrant special attention in the allocation of resources and development of programs to improve student well-being
Automated Propulsion Data Screening demonstration system
A fully-instrumented firing of a propulsion system typically generates a very large quantity of data. In the case of the Space Shuttle Main Engine (SSME), data analysis from ground tests and flights is currently a labor-intensive process. Human experts spend a great deal of time examining the large volume of sensor data generated by each engine firing. These experts look for any anomalies in the data which might indicate engine conditions warranting further investigation. The contract effort was to develop a 'first-cut' screening system for application to SSME engine firings that would identify the relatively small volume of data which is unusual or anomalous in some way. With such a system, limited and expensive human resources could focus on this small volume of unusual data for thorough analysis. The overall project objective was to develop a fully operational Automated Propulsion Data Screening (APDS) system with the capability of detecting significant trends and anomalies in transient and steady-state data. However, the effort limited screening of transient data to ground test data for throttle-down cases typical of the 3-g acceleration, and for engine throttling required to reach the maximum dynamic pressure limits imposed on the Space Shuttle. This APDS is based on neural networks designed to detect anomalies in propulsion system data that are not part of the data used for neural network training. The delivered system allows engineers to build their own screening sets for application to completed or planned firings of the SSME. ERC developers also built some generic screening sets that NASA engineers could apply immediately to their data analysis efforts
Ecological Effects of Fear: How Spatiotemporal Heterogeneity in Predation Risk Influences Mule Deer Access to Forage in a Sky‐Island System
Forage availability and predation risk interact to affect habitat use of ungulates across many biomes. Within sky‐island habitats of the Mojave Desert, increased availability of diverse forage and cover may provide ungulates with unique opportunities to extend nutrient uptake and/or to mitigate predation risk. We addressed whether habitat use and foraging patterns of female mule deer (Odocoileus hemionus) responded to normalized difference vegetation index (NDVI), NDVI rate of change (green‐up), or the occurrence of cougars (Puma concolor). Female mule deer used available green‐up primarily in spring, although growing vegetation was available during other seasons. Mule deer and cougar shared similar habitat all year, and our models indicated cougars had a consistent, negative effect on mule deer access to growing vegetation, particularly in summer when cougar occurrence became concentrated at higher elevations. A seemingly late parturition date coincided with diminishing NDVI during the lactation period. Sky‐island populations, rarely studied, provide the opportunity to determine how mule deer respond to growing foliage along steep elevation and vegetation gradients when trapped with their predators and seasonally limited by aridity. Our findings indicate that fear of predation may restrict access to the forage resources found in sky islands
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Corrigendum: Thiotepa hyperpigmentation preceding epidermal necrosis: malignant intertrigo misdiagnosed as Stevens-Johnson syndrome-toxic epidermal necrolysis overlap
The original article was published on February 15, 2020 and corrected on March 15, 2020.The revised version of the article corrects the contact information of the Corresponding Author. The changes appear in the revised online PDF copy of this article
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