Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)

This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 187

This supplement to Aerospace Medicine and Biology lists 247 reports, articles and other documents announced during November 1978 in Scientific and Technical Aerospace Reports (STAR) or in International Aerospace Abstracts (IAA). In its subject coverage, Aerospace Medicine and Biology concentrates on the biological, physiological, psychological, and environmental effects to which man is subjected during and following simulated or actual flight in the earth's atmosphere or in interplanetary space. References describing similar effects of biological organisms of lower order are also included. Emphasis is placed on applied research, but reference to fundamental studies and theoretical principles related to experimental development also qualify for inclusion. Each entry in the bibliography consists of a bibliographic citation accompanied in most cases by an abstract

Use of remote sensing for land use policy formulation

The use of remotely sensed data for eliminating abuses and mismanagement of land and water resources in Michigan is discussed. Applications discussed include inventory of mosquito breeding sites; analysis of biomass in old field ecosystems used for wastewater recycling; areas for agricultural use; and preservation of the Grand Mere Dune environment. Services to users are described and contact activities reported

Biterm Topic Modelを用いたeラーニングコースのレポート分類

近年、Computer Supported Collaborative Learning（CSCL）システムが開発されている。CSCLはコンピュータ技術を利用して、学習コミュニティの中での知識の共有と建設を特徴としている。しかし、CSCLは同時に同一トピックを学習するメンバによって構成される学習コミュニティを支援するので，メンバの熟達レベルの多様性が小さく，他者から学び方や学習成果を共有できる範囲は限定される。この制限を克服するために、eポートフォリオシステムは提案されている。E-ポートフォリオシステムは長年にわたって学習者の成果や情報を収集することができる。これらのデータから有用な情報を見つけて、他の学習者を助けるために、トピックモデルが適用されているeポートフォリオシステムが提案されている。　　トピックモデルは、ドキュメントのコレクションで発生する抽象的な「トピック」を発見するための統計モデルの一種である。Latent Dirichlet Allocation（LDA）は、eポートフォリオに適用することが提案されている。しかし、LDA はデータがスパースな場合、推定精度が落ちるなどの問題がある。まず、短い文書では、ほとんどの単語が一度だけしか出現しない。つまり、単語の出現頻度から、重要な単語を識別なことが困難である。第二に、多くの単語の意味は、その単語が出現する文脈によって決定される。短い文章では、関連する単語の数によって制限されてきたので、それが曖昧な単語のトピックを識別することは困難である。こんなデータのスパースは、伝統的なトピックモデルの推定精度に影響を与える。この問題に対処するために、Biterm Topic Model（BTM）が提案されている。本研究では、文書分類のための代わりにLDAのBTMを使用するように触発されている。 　 BTMのパフォーマンスを測定するために、本研究は、eラーニングシステム"samurai"に蓄積されている学習者レポートを用いた。実験の結果は、1）BTMはLDAより推定したトピックを構成する単語の一貫性が高い。2）BTMはLDAよりトピックの推定精度が高い。電気通信大学201

Development of a potential challenge model and plant-produced vaccine candidate for beak and feather disease virus

Psittacine beak and feather disease (PBFD), the most prevalent viral disease affecting psittacines, is caused by beak and feather disease virus (BFDV). An outbreak of the disease has been reported in wild endangered Cape parrots (Poicephalus robustus), which is endemic to South Africa. No treatment or vaccine is commercially available. In this study, an investigation into the outbreak was undertaken. BFDV diversity was assessed and viral load and clinical signs correlated. A plant-produced BFDV subunit vaccine was produced in parallel with a corresponding challenge model. Cape parrots were assessed and 53 blood samples collected. Viral load was determined using quantitative real-time PCR (qPCR), and 22 BFDV full-length genome sequences acquired to infer phylogenetic relatedness. The capsid gene (cp) was optimised for transient Agrobacterium-mediated expression in whole-plant Nicotiana benthamiana (N. benthamiana). Virus-like particles (VLPs) were purified and analysed using transmission electron microscopy. Virions from a Palm cockatoo (Probosciger aterrimus) were purified and a BFDV dsDNA molecular clone was synthesised and replication assessed in 293TT mammalian cells and N. benthamiana using rolling circle replication and qPCR. Two distinct BFDV phylogenetic clusters were reported for Cape parrots, and a direct correlation was seen between viral load in the blood and clinical signs in PBFD-afflicted birds. The CP was successfully expressed in N. benthamiana, and increased through optimisation of Agrobacterium infiltration density and the inclusion of the NSs silencing suppressor. The CP formed VLPs, which were shown to be morphologically similar to infectious virions. The dsDNA molecular clone was shown to replicate autonomously in mammalian 293TT cells, and in plants with the assistance of the Bean yellow dwarf virus replication associated protein (Rep). BFDV genetic diversity in Cape parrots highlights the importance of ensuring new strains are not inadvertently introduced into the wild. This is the first systematic investigation of virus diversity in Cape parrots and assessment of BFDV viral load in a wild psittacine population. The CP was successfully produced in planta and presence of VLPs suggests the possibility of developing pseudovirions. This is the first reported replication of BFDV in tissue culture, and will greatly expand the scope of available research

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 212

A bibliography listing 146 reports, articles, and other documents introduced into the NASA scientific and technical information system is presented. The subject coverage concentrates on the biological, psychological, and environmental factors involved in atmospheric and interplanetary flight. Related topics such as sanitary problems, pharmacology, toxicology, safety and survival, life support systems, and exobiology are also given attention

Quarterly literature review of the remote sensing of natural resources

The Technology Application Center reviewed abstracted literature sources, and selected document data and data gathering techniques which were performed or obtained remotely from space, aircraft or groundbased stations. All of the documentation was related to remote sensing sensors or the remote sensing of the natural resources. Sensors were primarily those operating within the 10 to the minus 8 power to 1 meter wavelength band. Included are NASA Tech Briefs, ARAC Industrial Applications Reports, U.S. Navy Technical Reports, U.S. Patent reports, and other technical articles and reports

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 361)

This bibliography lists 141 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during Mar. 1992. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Review on Barely Yellow Dwarf Viruses

Barley yellow dwarf virus (BYDV) is distributed worldwide, and infects most cereals and grasses. It is a phloem-restricted pathogen, causing yellowing, reddening, and brittleness of leaves, dwarfing, and reduction in size and number of ears and grains. BYDV is a luteovirus with small isometric particles containing an ssRNA genome, and is transmitted persistently by more than 20 aphid species. Five virus isolates have been distinguished and divided into two subgroups on the basis of cytopathology and serology. Recent serological evidence also indicates that BYDV isolates are related to other luteoviruses, suggesting that a continuous, over lapping range of viruses may be implicated in the barley yellow dwarf syndrome. Until future research clarifies this point, the term BYDV continues to be used to indicate the agent(s) involved. Perennial wild or cultivated grasses constitute a large and permanent virus pool. Primary and secondary virus spread depends on the aphid vector reproduction and flight which, in turn, are influenced by climatic conditions. Recent research on monitoring and control of aphid vectors and on development of resistant cereal cultivars has improved the prospect of minimizing losses from BYDV infections. Because of the economic importance of the BYDVs, more research is needed. The specific locations and timing of virus outbreaks, and the particular causal isolates, need to be monitored. This is will allow breeders to decide which BYDV isolate to target with transgenic resistance in a given locality. It will help growers decide whether to pay the extra premium for BYDV-resistant crops. Another area of applied research may be to engineer aphid-resistant crops. With the growing number of sequenced or partially sequenced isolates of BYDV and CYDV around the world, it’s important 1) to develop rapid means of nucleic acid-based detection (e.g., PCR), 2) to understand the epidemiology of BYDV/CYDV, and 3) to develop transgenic and other means of disease control. The better understanding of BYDV molecular mechanisms that ultimately lead to new means of controlling or mitigating the effects of the disease, and it sheds light on processes relevant to medically important viruses. In addition, further review is needed to identify all recovered BYDV and evaluation of promising treatments for use in integrated disease management strategy to manage not only BYDV but also other related viral diseases of plant. Keywords: Barley, Barley yellow dwarf virus (BYDV), and luteovirus