368 research outputs found

    The Influence of Pervasive Algorithms on Programming Languages

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    Many leading analysts would agree that, had it not been for model checking, the improvement of suffix trees might never have occurred. In fact, few security experts would disagree with the synthesis of multicast systems. Tas, our new heuristic for the analysis of online algorithms, is the solution to all of these issues

    Helminth Parasites of the Brown-Headed Cowbird, Molothrus Ater Ater, from Ohio

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    Author Institution: Department of Zoology, The Ohio State UniversityA total of 166 Brown-headed Cowbirds was examined for the occurrence of helminth parasites. Of these, 116 were collected on the campus of The Ohio State University, Franklin County, Ohio, from January 1964 through February 1965. The remainder of the birds were collected on South Bass Island, Ottawa County, Ohio, from July 1969 through July 1970. Twenty species of helminth parasites are recorded from these birds. Sixteen of these helminth species are new host records: the trematodes Conspicuum icteridorum, Lutztrema sp., Prosthogonimus macrorchis, Tanaisia zarudnyi, and Zonorchis alveyi; the cestode Orthoskrjabinia rostellata; the nematodes Capillaria caudinflata, C. ovopunctatum, C. tridens, Chandlerella quiscali, Diplotriaena bargusinica, Microtetrameres sp., Splendidofilaria algonquinensis, Syngamus trachea, and Tetrameres americana; and the acanthocephalan Plagiorhynchus formosus

    Distribution and abundance of humpback whales (Megaptera novaeangliae) and other marine mammals off the northern Washington coast

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    We examined the summer distribution of marine mammals off the northern Washington coast based on six ship transect surveys conducted between 1995 and 2002, primarily from the NOAA ship McArthur. Additionally, small boat surveys were conducted in the same region between 1989 and 2002 to gather photographic identification data on humpback whales (Megaptera novaeangliae) and killer whales (Orcinus orca) to examine movements and population structure. In the six years of ship survey effort, 706 sightings of 15 marine mammal species were made. Humpback whales were the most common large cetacean species and were seen every year and a total of 232 sightings of 402 animals were recorded during ship surveys. Highest numbers were observed in 2002, when there were 79 sightings of 139 whales. Line-transect estimates for humpback whales indicated that about 100 humpback whales inhabited these waters each year between 1995 and 2000; in 2002, however, the estimate was 562 (CV= 0.21) whales. A total of 191 unique individuals were identified photographically and mark recapture estimates also indicated that the number of animals increased from under 100 to over 200 from 1995 to 2002. There was only limited interchange of humpback whales between this area and feeding areas off Oregon and California. Killer whales were also seen on every ship survey and represented all known ecotypes of the Pacific Northwest, including southern and northern residents, transients, and offshore-type killer whales. Dall’s porpoise (Phocoenoides dalli) were the most frequently sighted small cetacean; abundance was estimated at 181−291 individuals, except for 2002 when we observed dramatically higher numbers (876, CV= 0.30). Northern fur seals (Callorhinus ursinus) and elephant seals (Mirounga angustirostris) were the most common pinnipeds observed. There were clear habitat differences related to distance offshore and water depth for different species

    CO and H+3 Toward MWC 1080, MWC 349, and LkHα 101

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    We present high-resolution, near-infrared NIRSPEC observations of the fundamental rovibrational CO and H+ 3 R(1,0), R(1,1) u , and Q(1,0) transitions toward three early-type young stars: MWC 1080, MWC 349, and LkHα 101. These observations were performed for the purpose of constraining the physical characteristics of the interstellar material along each line of sight. Toward MWC 1080, we detected strong CO absorption and determined a column density upper limit of 1.4 × 1014 cm–2 for H+ 3. We infer that there is very little diffuse material along the line of sight toward MWC 1080 and that the CO absorption is consistent with an origin in the dispersing natal cloud. We detected both cold CO and H+ 3 toward MWC 349, consistent with a diffuse cloud origin. Similarly, both CO and H+ 3 were detected toward LkHα 101. Using a recently revised value for the cosmic ray ionization rate, we conclude that the CO absorption is consistent with a dense cloud origin while the H+ 3 could originate in either the dense or diffuse interstellar medium. We also find no evidence for CO fractionation toward LkHα 101 as reported by Goto et al

    Space robotics: Recent accomplishments and opportunities for future research

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    The Langley Guidance, Navigation, and Control Technical Committee (GNCTC) was one of six technical committees created in 1991 by the Chief Scientist, Dr. Michael F. Card. During the kickoff meeting Dr. Card charged the chairmen to: (1) establish a cross-Center committee; (2) support at least one workshop in a selected discipline; and (3) prepare a technical paper on recent accomplishments in the discipline and on opportunities for future research. The Guidance, Navigation, and Control Committee was formed and selected for focus on the discipline of Space robotics. This report is a summary of the committee's assessment of recent accomplishments and opportunities for future research. The report is organized as follows. First is an overview of the data sources used by the committee. Next is a description of technical needs identified by the committee followed by recent accomplishments. Opportunities for future research ends the main body of the report. It includes the primary recommendation of the committee that NASA establish a national space facility for the development of space automation and robotics, one element of which is a telerobotic research platform in space. References 1 and 2 are the proceedings of two workshops sponsored by the committee during its June 1991, through May 1992 term. The focus of the committee for the June 1992 - May 1993 term will be to further define to the recommended platform in space and to add an additional discipline which includes aircraft related GN&C issues. To the latter end members performing aircraft related research will be added to the committee. (A preliminary assessment of future opportunities in aircraft-related GN&C research has been included as appendix A.

    Development and fabrication of a fast recovery, high voltage power diode

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    The use of positive bevels for P-I-N mesa structures to achieve high voltages is described. The technique of glass passivation for mesa structures is described. The utilization of high energy radiation to control the lifetime of carriers in silicon is reported as a means to achieve fast recovery times. Characterization data is reported and is in agreement with design concepts developed for power diodes

    Neutralization of Diverse Human Cytomegalovirus Strains Conferred by Antibodies Targeting Viral gH/gL/pUL128-131 Pentameric Complex

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    Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection, and developing a prophylactic vaccine is of high priority to public health. We recently reported a replication-defective human cytomegalovirus with restored pentameric complex glycoprotein H (gH)/gL/pUL128-131 for prevention of congenital HCMV infection. While the quantity of vaccine-induced antibody responses can be measured in a viral neutralization assay, assessing the quality of such responses, including the ability of vaccine-induced antibodies to cross-neutralize the field strains of HCMV, remains a challenge. In this study, with a panel of neutralizing antibodies from three healthy human donors with natural HCMV infection or a vaccinated animal, we mapped eight sites on the dominant virus-neutralizing antigen-the pentameric complex of glycoprotein H (gH), gL, and pUL128, pUL130, and pUL131. By evaluating the site-specific antibodies in vaccine immune sera, we demonstrated that vaccination elicited functional antiviral antibodies to multiple neutralizing sites in rhesus macaques, with quality attributes comparable to those of CMV hyperimmune globulin. Furthermore, these immune sera showed antiviral activities against a panel of genetically distinct HCMV clinical isolates. These results highlighted the importance of understanding the quality of vaccine-induced antibody responses, which includes not only the neutralizing potency in key cell types but also the ability to protect against the genetically diverse field strains. IMPORTANCE HCMV is the leading cause of congenital viral infection, and development of a preventive vaccine is a high public health priority. To understand the strain coverage of vaccine-induced immune responses in comparison with natural immunity, we used a panel of broadly neutralizing antibodies to identify the immunogenic sites of a dominant viral antigen-the pentameric complex. We further demonstrated that following vaccination of a replication-defective virus with the restored pentameric complex, rhesus macaques can develop broadly neutralizing antibodies targeting multiple immunogenic sites of the pentameric complex. Such analyses of site-specific antibody responses are imperative to our assessment of the quality of vaccine-induced immunity in clinical studies

    Harry Reid Center of Environmental Studies: Quality assurance program evaluation

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    The Quality Assurance (QA) Program is critical in the licensing of the Yucca Mountain Repository because it helps ensure that the information used to demonstrate the safer)\u27 of the repository is defensible and well documented. Through audits and surveillances the QA staff identifies areas of non-compliance within each task. The QA Program at the Harry Reid Center (HRC) for Environmental Studies can increase compliance with Quality /Assurance Procedures (QAPs) by improving the program\u27s process. Through qualitative and quantitative research it was determined that reasons for non-compliance revolved around three key areas; process, communication and training. Communication and training are key components of the process for ensuring compliance. Therefore, our recommendations focus on process improvements. This evaluation contains recommendations related to improving processes within the QA Program. In particular, the QA Program should enhance its current training program by making it more hands on, utilising pre/post-tests, requiring mandatory annual training, creating an easy to use reference manual and hiring a full time trainer. In addition, communication can be improved by increasing the number of meetings between Pis and researchers, having mandatory regularly scheduled meetings with QA staff in the Reno area, and creating and maintaining a database for all statt associated with every task. Finally, the QA Program should create incentives for compliance and consequences for noncompliance

    Maternal Management of Social Relationships as a Correlate of Children's School-Based Experiences

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    Abstract We tested a model considering the manner in which mothers' use of their own social relationships and efforts to facilitate their children's school-based social relationships were associated with two distinct types of school-based competence: academic achievement and levels of stress experienced within the school environment. Fourth grade children (n = 311) and their mothers participated in interviews and completed questionnaires providing information on social relationships and school experiences. Structural equation modeling (SEM) analyses indicated a good fit for a model in which mothers' efforts to facilitate children's social relationships with peers were associated with lower levels of school-based stress, but mothers' efforts to maintain social connections with the parents of their children's school friends were linked with lower levels of objectively measured academic achievement

    Limiting distributions for explosive PAR(1) time series with strongly mixing innovation

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    This work deals with the limiting distribution of the least squares estimators of the coefficients a r of an explosive periodic autoregressive of order 1 (PAR(1)) time series X r = a r X r--1 +u r when the innovation {u k } is strongly mixing. More precisely {a r } is a periodic sequence of real numbers with period P \textgreater{} 0 and such that P r=1 |a r | \textgreater{} 1. The time series {u r } is periodically distributed with the same period P and satisfies the strong mixing property, so the random variables u r can be correlated
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