848 research outputs found
Comprehension and retrieval of failure cases in airborne observatories
This paper describes research dealing with the computational problem of analyzing and repairing failures of electronic and mechanical systems of telescopes in NASA's airborne observatories, such as KAO (Kuiper Airborne Observatory) and SOFIA (Stratospheric Observatory for Infrared Astronomy). The research has resulted in the development of an experimental system that acquires knowledge of failure analysis from input text, and answers questions regarding failure detection and correction. The system's design builds upon previous work on text comprehension and question answering, including: knowledge representation for conceptual analysis of failure descriptions, strategies for mapping natural language into conceptual representations, case-based reasoning strategies for memory organization and indexing, and strategies for memory search and retrieval. These techniques have been combined into a model that accounts for: (a) how to build a knowledge base of system failures and repair procedures from descriptions that appear in telescope-operators' logbooks and FMEA (failure modes and effects analysis) manuals; and (b) how to use that knowledge base to search and retrieve answers to questions about causes and effects of failures, as well as diagnosis and repair procedures. This model has been implemented in FANSYS (Failure ANalysis SYStem), a prototype text comprehension and question answering program for failure analysis
Fragments of the earliest land plants
The earliest fossil evidence for land plants comes from microscopic dispersed spores. These microfossils are abundant and widely distributed in sediments, and the earliest generally accepted reports are from rocks of mid-Ordovician age (Llanvirn, 475 million years ago). Although distribution, morphology and ultrastructure of the spores indicate that they are derived from terrestrial plants, possibly early relatives of the bryophytes, this interpretation remains controversial as there is little in the way of direct evidence for the parent plants. An additional complicating factor is that there is a significant hiatus between the appearance of the first dispersed spores and fossils of relatively complete land plants (megafossils): spores predate the earliest megafossils (Late Silurian, 425 million year ago) by some 50 million years. Here we report the description of spore-containing plant fragments from Ordovician rocks of Oman. These fossils provide direct evidence for the nature of the spore-producing plants. They confirm that the earliest spores developed in large numbers within sporangia, providing strong evidence that they are the fossilized remains of bona fide land plants. Furthermore, analysis of spore wall ultrastructure supports liverwort affinities
Childhood IQ and marriage by mid-life: the Scottish Mental Survey 1932 and the Midspan Studies
The study examined the influence of IQ at age 11 years on marital status by mid-adulthood. The combined databases of the Scottish Mental Survey 1932 and the Midspan studies provided data from 883 subjects. With regard to IQ at age 11, there was an interaction between sex and marital status by mid-adulthood (p = 0.0001). Women who had ever-married achieved mean lower childhood IQ scores than women who had never-married (p < 0.001). Conversely, there was a trend for men who had ever-married to achieve higher childhood IQ scores than men who had never-married (p = 0.07). In men, the odds ratio of ever marrying was 1.35 (95% CI 0.98–1.86; p = 0.07) for each standard deviation increase in childhood IQ. Among women, the odds ratio of ever marrying by mid-life was 0.42 (95% CI 0.27–0.64; p = 0.0001) for each standard deviation increase in childhood IQ. Mid-life social class had a similar association with marriage, with women in more professional jobs and men in more manual jobs being less likely to have ever-married by mid-life. Adjustment for the effects of mid-life social class and height on the association between childhood IQ and later marriage, and vice versa, attenuated the effects somewhat, but suggested that IQ, height and social class acted partly independently
Association between serum uric acid and prostate cancer mortality in androgen deprivation therapy: A population‐based cohort study
Objective
This population-based study examined the association between baseline uric acid (UA) and prostate cancer (PCa)-related mortality amongst PCa patients receiving androgen deprivation therapy (ADT).
Methods
Adults with PCa who received ADT in Hong Kong between December 1999 and March 2021 were identified. Patients with missing baseline UA were excluded. Patients were followed up until September 2021. The outcome was PCa-related mortality.
Results
Altogether, 4126 patients (median follow-up 3.1[interquartile range 1.4–6.0] years) were included. A J-shaped association was observed between baseline UA level and PCa-related mortality risk, with a direct association in those with mean(0.401 mmol/L) or above-mean baseline UA levels (hazard ratio (HR) per standard deviation-increase 1.35 [95% confidence interval 1.21,1.51], p < 0.001), and an inverse association in those with below-mean baseline UA levels (HR 0.78[0.67,0.92], p = 0.003). The former remained significant on competing risk regression, but not the latter.
Conclusions
A J-shaped relationship between baseline UA level and PCa-related mortality risk was identified. This study was mainly limited by potential unmeasured and residual confounders. Further validation studies are warranted
Associations between glucocorticoid use and major adverse cardiovascular events in patients with prostate cancer receiving antiandrogen: a retrospective cohort study.
Prednisolone/prednisone coadministration with abiraterone may explain abiraterone-related increase in cardiovascular risk. We explored this postulation and glucocorticoid's association with cardiovascular risk. Patients with prostate cancer on androgen deprivation therapy and enzalutamide, or abiraterone with 5 mg (ABI + P5) or 10 mg (ABI + P10) daily total prednisolone/prednisone were followed up for major adverse cardiovascular events (MACE). We analyzed 933 patients. ABI + P10, but not enzalutamide, had higher risk of MACE than ABI + P5. Cumulative glucocorticoid dose before enzalutamide/abiraterone initiation was associated with MACE. Prednisolone/prednisone coadministration with abiraterone likely contributed to abiraterone-related increased cardiovascular risk. Prevalent cumulative glucocorticoid dose was associated with cardiovascular risk. [Abstract copyright: © 2024. The Author(s).
Land Rights and the Forest Peoples of Africa: Historical, Legal and Anthropological Perspectives
This composite publication
presents and complements a
study conducted on the land
rights of indigenous peoples in
five countries of the forested
region of Africa, namely
Burundi, Cameroon, Democratic
Republic of Congo (DRC),
Rwanda and Uganda. Building
on historical facts and legal
developments, the study
highlights indigenous peoples’
loss of resources and land to
colonists, commercial enter-
prises and conservation initiatives. It also de
scribes how, having been dispossessed of their
ancestral lands and, in many cases, not alloca
ted alternative land, indi
genous forest peoples
in Africa today live in extremely vulnerable
conditions and experience marginalisation and
poverty
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