A reconsideration of some Jāhilī poetic paradigms

The J=ahil=i poets esteemed verity as opposed to verisimilitude as their principal aesthetic criterion. I have long been convinced of this. This thesis represents an attempt to enucleate several features of their verse by drawing on various spheres of knowledge, acquaintance with which is fundamental to a proper appreciation of the pre-Islamic qad s=idah as poetry. My concern has been with matters zoological, philological, literary and socio-historical. It is a critical shibboleth (both occidental and oriental) that the ancients Arabs were unlettered; yet writing looms large in their verse. It is a modern datum that J=ahil=i verse is oral poetry; yet this is not the only explantion for the recurrence of conventional phraseology and expression. Chapter One is a preliminary incursus into an investigation of writing among the early Arabs. It is also a study of the literary development of a nexus of topical comparisons, viz. the deserted encampment. A socio-historical interpretation of the shift in emphasis perceptible in these comparisons is offered, conjoined with the suggestion that the phenomenon of the `Bedouin' is an incremental paradigm, the presence of which is less distinct in early J=ahil=i verse than has been supposed. Extended similes in which a camel is compared with an oryx bull or doe or a wild ass have tended to be neglected by scholars, who rely on an, at times but poorly formed, subjective impression, referring to the stylized or mannered nature of the tableaux. I have tried to demonstrate that, although in their several features narrative consuetude is discernible, a proper understanding of the vignettes depends largely on the given poetic context. The ethology and ecology of the ass and the oryx have been studied in order to shed light on their poetical manifestations: verse has proved to be consistent with science. Chapter 4 sets forth a comparison of the parodical style of Arkhilokhos of Paros and al-N=abighah of the tribe of Dhuby=an, to which an instance of parody from the Middle English alliterative tradition has been appended

Resource allocation, information cost and the form of government intervention.

[No abstract

SDSS J142625.71+575218.3: A Prototype for A New Class of Variable White Dwarf

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. On the basis of our theoretical calculations, the star SDSS J142625.71 + 575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s ( first harmonic), making it a strong candidate as the first member of a new class of pulsating white dwarf stars, the DQVs. Its folded pulse shape, however, is quite different from that of other white dwarf variables and shows similarities with that of the cataclysmic variable AM CVn, raising the possibility that this star may be a carbon-transferring analog of AM CVn stars. In either case, these observations represent the discovery of a new and exciting class of object.NSF AST-0507639, AST-0602288, AST-0607480, AST-0307321Astronom

Hazard Detection Software for Lunar Landing

The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project is developing a system for safe and precise manned lunar landing that involves novel sensors, but also specific algorithms. ALHAT has selected imaging LIDAR (light detection and ranging) as the sensing modality for onboard hazard detection because imaging LIDARs can rapidly generate direct measurements of the lunar surface elevation from high altitude. Then, starting with the LIDAR-based Hazard Detection and Avoidance (HDA) algorithm developed for Mars Landing, JPL has developed a mature set of HDA software for the manned lunar landing problem. Landing hazards exist everywhere on the Moon, and many of the more desirable landing sites are near the most hazardous terrain, so HDA is needed to autonomously and safely land payloads over much of the lunar surface. The HDA requirements used in the ALHAT project are to detect hazards that are 0.3 m tall or higher and slopes that are 5 or greater. Steep slopes, rocks, cliffs, and gullies are all hazards for landing and, by computing the local slope and roughness in an elevation map, all of these hazards can be detected. The algorithm in this innovation is used to measure slope and roughness hazards. In addition to detecting these hazards, the HDA capability also is able to find a safe landing site free of these hazards for a lunar lander with diameter .15 m over most of the lunar surface. This software includes an implementation of the HDA algorithm, software for generating simulated lunar terrain maps for testing, hazard detection performance analysis tools, and associated documentation. The HDA software has been deployed to Langley Research Center and integrated into the POST II Monte Carlo simulation environment. The high-fidelity Monte Carlo simulations determine the required ground spacing between LIDAR samples (ground sample distances) and the noise on the LIDAR range measurement. This simulation has also been used to determine the effect of viewing on hazard detection performance. The software has also been deployed to Johnson Space Center and integrated into the ALHAT real-time Hardware-in-the-Loop testbed

Resource allocation, information cost and the form of government intervention.

[No abstract

Avionics Architectures for Exploration: Building a Better Approach for (Human) Spaceflight Avionics

The field of Avionics is advancing far more rapidly in terrestrial applications than in space flight applications. Spaceflight Avionics are not keeping pace with expectations set by terrestrial experience, nor are they keeping pace with the need for increasingly complex automation and crew interfaces as we move beyond Low Earth Orbit. NASA must take advantage of the strides being made by both space-related and terrestrial industries to drive our development and sustaining costs down. This paper describes ongoing efforts by the Avionics Architectures for Exploration (AAE) project chartered by NASA's Advanced Exploration Systems (AES) Program to evaluate new avionic architectures and technologies, provide objective comparisons of them, and mature selected technologies for flight and for use by other AES projects. Results from the AAE project's FY13 efforts are discussed, along with the status of FY14 efforts and future plans

Myopia in late adolescence and subsequent multiple sclerosis among men

BACKGROUND: Risk factors such as low vitamin D level has been implicated in the etiology of multiple sclerosis (MS) and may be relevant to myopia, such that there may be an association between myopia and MS. METHODS: Using linked Swedish national register data, we conducted a cohort study of men who were born in Sweden between 1950 and 1992, lived in Sweden between 1990 and 2018, and enrolled in military conscription assessment (n = 1,847,754). Myopia was defined based on the spherical equivalent refraction measured at conscription assessment, around age 18 years. Multiple sclerosis was identified using the Patient Register. Cox regression produced hazard ratios (HR) with 95% confidence intervals (95% CI), with adjustment for demographic and childhood socioeconomic characteristics and residential region. Due to changes in the assessment of refractive error, the analysis was stratified into two groups by the year of conscription assessment: 1969-1997 and 1997-2010. RESULTS: Among 1,559,859 individuals during a maximum of 48 years of follow-up from age 20 to 68 years (44,715,603 person-years), there were 3,134 MS events, and the incidence rate 7.0 (95% CI [6.8, 7.3] per 100,000 person-years). Among individuals with conscription assessments during 1997-2010, there were 380 MS events. There was no evidence of an association between myopia and MS, with HR 1.09 (95% CI 0.83, 1.43). Among individuals who underwent conscription assessment in 1969-1997, there were 2754 MS events. After adjusting for all covariates, there was no evidence of an association between myopia and MS (HR 0.99 [95% CI 0.91, 1.09]). CONCLUSION: Myopia in late adolescence is not associated with a subsequent raised risk of MS and thus there does not appear to be important shared risk factors

Avionics Architectures for Exploration: Wireless Technologies and Human Spaceflight

The authors describe ongoing efforts by the Avionics Architectures for Exploration (AAE) project chartered by NASA's Advanced Exploration Systems (AES) Program to evaluate new avionics architectures and technologies, provide objective comparisons of them, and mature selected technologies for flight and for use by other AES projects. The AAE project team includes members from most NASA centers and from industry. This paper provides an overview of recent AAE efforts, with particular emphasis on the wireless technologies being evaluated under AES to support human spaceflight