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Sample records for short communication high

  1. Hard plastic cladding fiber (HPCF) based optical components for high speed short reach optical communications

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ki; Kim, Dong Uk; Kim, Tae Young; Park, Chang Soo; Oh, Kyunghwan

    2006-09-01

    We developed the primary components applicable to HPCF links for short reach (SR) and very short reach (VSR) data communication systems. We fabricated 4x4 HPCF fused taper splitter, HPCF pigtailed VCSEL and PIN photodiode for high speed short reach communications and characterized back to back transmission performance of the link composed of these components by measuring eye diagrams and jitters. Adapting the fusion-tapering technique for glass optical fiber, we successfully fabricated a 4x4 HPCF fused taper coupler. The HPCF with a core diameter of 200μm and an outer diameter of 230μm had step refractive index of 1.45 and 1.40 for the core and the clad. The optimized fusion length and tapering waist which make minimum insertion loss of about 7dB and uniform output power splitting ratio with less than 0.5dB are 13mm and 150µm, respectively. As a light source for VSR networks, we chose a vertical cavity surface emitting laser (VCSEL) and developed a package with a HPCF pigtail. After positioning VCSEL and HPCF that made a minimum coupling loss, we glued the HPCF inside ceramic ferrule housing. In HPCF-PIN PD packaging, we added a micro polymer lens tip onto the HPCF ends to match the mode field area to the sensitive area of GaAs or InGaAs PIN PD. Coupling between a PIN PD chip and the lensed HPCF was optimized with the radius of curvature of 156µm with a low coupling loss of 0.3dB, which is compatible to conventional MMF-PD packaging. For 1.25 Gbps data rate, the eyes adequate to eye mask in gigabit Ethernet were wide open after all HPCF transmission link and no significant power penalty was observed.

  2. Intentionally Short Range Communications (ISRC)

    NASA Astrophysics Data System (ADS)

    Yen, J.; Poirier, P.; Obrien, M. E.; Gibeson, L.

    1993-05-01

    This document details the feasibility studies conducted for the Intentionally Short Range Communications (ISRC) project. The short-range limitation arises from the need for low probability of intercept (LPI), low probability of detection (LPD) communication links. The detection of an undecipherable transmission would still provide an enemy with information regarding transmitter location. The technologies being studied are ultraviolet (UV) lamps, UV lasers, infrared (IR) lasers, millimeter waves (MMW), and direct sequence spread spectrum.

  3. Robust Short-Pulse, High-Peak-Power Laser Transmitter for Optical Communications

    NASA Technical Reports Server (NTRS)

    Wright, Malcolm W.

    2009-01-01

    We report on a pulsed fiber based master oscillator power amplifier laser at 1550 nm to support moderate data rates with high peak powers in a compact package suitable for interplanetary optical communications. To accommodate pulse position modulation, the polarization maintaining laser transmitter generates pulses from 0.1 to 1 ns with variable duty cycle over a pulse repetition frequency range of 10 to 100 MHz.

  4. Short-range communication system

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2012-01-01

    A short-range communication system includes an antenna, a transmitter, and a receiver. The antenna is an electrical conductor formed as a planar coil with rings thereof being uniformly spaced. The transmitter is spaced apart from the plane of the coil by a gap. An amplitude-modulated and asynchronous signal indicative of a data stream of known peak amplitude is transmitted into the gap. The receiver detects the coil's resonance and decodes same to recover the data stream.

  5. High prevalence of intestinal zoonotic parasites in dogs from Belgrade, Serbia--short communication.

    PubMed

    Nikolić, Aleksandra; Dimitrijević, Sanda; Katić-Radivojević, Sofija; Klun, Ivana; Bobrć, Branko; Djurković-Djaković, Olgica

    2008-09-01

    To identify areas of risk for canine-related zoonoses in Serbia, the aim of this study was to provide baseline knowledge about intestinal parasites in 151 dogs (65 household pets, 75 stray and 11 military working dogs) from Belgrade. The following parasites, with their respective prevalences, were detected: Giardia duodenalis (14.6%), Ancylostomatidae (24.5%), Toxocara canis (30.5%), Trichuris vulpis (47.0%) and Taenia-type helminths (6.6%). Of all examined dogs, 75.5% (114/151) were found to harbour at least one parasite species. Of these, mixed infections with up to four species per dog occurred in 44.7% (51/114). Infections with all detected species were significantly higher (p < 0.05) in military working (100%) and stray dogs (93.3%) versus household pets (50.8%). Among all parasites, agents with zoonotic potential including Giardia, Ancylostomatidae and Toxocara were detected in 58.3% (88/151) of all examined dogs with a significant difference (p < 0.05) among the subgroups (100%, 62.7% and 46.2% for military working dogs, stray dogs and household pets, respectively). The high prevalence of zoonotic parasites registered in the dog population from a highly urban area in south-eastern Europe indicates a potential risk to human health. Thus, veterinarians should play an important role in helping to prevent or minimise zoonotic transmission. PMID:18828485

  6. Intentionally Short-Range Communications (ISRC)

    NASA Astrophysics Data System (ADS)

    Yen, J.; Poirier, P.; Obrien, M.

    1994-02-01

    The U.S. Marine Corps (USMC) desired to develop short-range communications links whose ranges are intentionally limited to very short distances. These links support tactical missions such as LAN Backbone, Wideband Data Link, and Company Radio. The short-range limitation arises from the need for low probability of detection and intercept (LPD/LPI). Since the detection of an undecipherable transmission would still provide an enemy with information regarding transmitter location and allow him to take countermeasures, the Marine Corps Systems Command (MARCORSYSCOM) is sponsoring the development of technologies that can be LPD by their very nature. The Intentionally Short-Range Communications (ISRC) project at the Naval Command, Control and Ocean Surveillance Center (NCCOSC) RDT&E Division (NRaD) is pursuing feasibility studies for these USMC missions based on such technologies as ultraviolet (LTV) lamps, UV lasers, infrared (IR) lasers, millimeter waves and direct sequence spread spectrum (DSSS) at radio frequencies.

  7. Short communication: Variation in production parameters among Canadian Holstein cows classified as high, average, and low immune responders.

    PubMed

    Stoop, C L; Thompson-Crispi, K A; Cartwright, S L; Mallard, B A

    2016-06-01

    Dairy cattle evaluated for immune responses and identified as high responders are known to have a lower occurrence of economically important diseases, including mastitis, metritis, ketosis, and retained placenta. These high immune responders have also been shown to make more antibody following vaccination and to have improved milk and colostrum quality. Therefore, breeding for improved immune response is expected to have several benefits in the dairy industry. However, a concern of such an approach to improve animal health is the potential cost of lost production due to an allocation of host resources to mount a robust immune response. The objective of this study was to evaluate early- and late-lactation production parameters in cattle classified as having high, average, or low estimated breeding values (EBV) for cell-mediated (CMIR), antibody-mediated (AMIR), and overall immune responses. A total of 561 cows from 6 herds were phenotyped for immune response and ranked based on EBV for CMIR and AMIR. A linear animal model was used to evaluate differences in milk, fat, and protein yields among immune response groups, and a regression analysis was conducted based on immune response EBV. Overall, no difference in production parameters was found based on immune response rank; however, some positive relationships with immune response EBV were found, suggesting that breeding for enhanced immune responsiveness as a prophylactic approach to improve animal health would not come at the cost of lost production. PMID:27060821

  8. Short communication: Effects of molasses supplementation on performance of lactating cows fed high-alfalfa silage diets.

    PubMed

    Baurhoo, B; Mustafa, A

    2014-02-01

    Twelve Holstein cows were used in a replicated Latin square experiment to determine the effect of adding dried molasses to high-alfalfa silage diets on dairy cow performance. Three isonitrogenous diets were formulated with a 68:32 forage:concentrate ratio, with alfalfa silage as the only forage source. Dietary treatments were a control diet with no added molasses and 3 and 6% dried molasses diets. Three lactating Holstein cows fitted with ruminal cannulas were used to determine the effects of dietary treatments on ruminal fermentation. Dietary treatments had no effect on dry matter (average 23.3 kg/d), crude protein (average 4.4 kg/d), or neutral detergent fiber (average 7.4 kg/d) intake. Milk yield, energy-corrected milk (average 35.4 kg/d), and 4% fat-corrected milk (average 33.8 kg/d) were not influenced by dietary treatments. Cows fed the control diet produced milk with less milk urea nitrogen concentration than those fed molasses-supplemented diets. Ruminal pH, NH3-N concentration, and total volatile fatty acids were not different among dietary treatments. The molar proportion of acetate linearly increased, whereas the molar proportion of propionate linearly decreased as the level of dried molasses increased. It was concluded that addition of dried molasses to high-alfalfa silage diets at 6% of the diet (dry matter basis) increased milk urea nitrogen but had no effect on animal performance. PMID:24315324

  9. Short Communication An efficient method for simultaneous extraction of high-quality RNA and DNA from various plant tissues.

    PubMed

    Oliveira, R R; Viana, A J C; Reátegui, A C E; Vincentz, M G A

    2015-01-01

    Determination of gene expression is an important tool to study biological processes and relies on the quality of the extracted RNA. Changes in gene expression profiles may be directly related to mutations in regulatory DNA sequences or alterations in DNA cytosine methylation, which is an epigenetic mark. Correlation of gene expression with DNA sequence or epigenetic mark polymorphism is often desirable; for this, a robust protocol to isolate high-quality RNA and DNA simultaneously from the same sample is required. Although commercial kits and protocols are available, they are mainly optimized for animal tissues and, in general, restricted to RNA or DNA extraction, not both. In the present study, we describe an efficient and accessible method to extract both RNA and DNA simultaneously from the same sample of various plant tissues, using small amounts of starting material. The protocol was efficient in the extraction of high-quality nucleic acids from several Arabidopsis thaliana tissues (e.g., leaf, inflorescence stem, flower, fruit, cotyledon, seedlings, root, and embryo) and from other tissues of non-model plants, such as Avicennia schaueriana (Acanthaceae), Theobroma cacao (Malvaceae), Paspalum notatum (Poaceae), and Sorghum bicolor (Poaceae). The obtained nucleic acids were used as templates for downstream analyses, such as mRNA sequencing, quantitative real time-polymerase chain reaction, bisulfite treatment, and others; the results were comparable to those obtained with commercial kits. We believe that this protocol could be applied to a broad range of plant species, help avoid technical and sampling biases, and facilitate several RNA- and DNA-dependent analyses. PMID:26782533

  10. Short communication: The effect of feeding high protein distillers dried grains on milk production of Holstein cows.

    PubMed

    Hubbard, K J; Kononoff, P J; Gehman, A M; Kelzer, J M; Karges, K; Gibson, M L

    2009-06-01

    The objectives of this study were to evaluate the effects of feeding high-protein distillers dried grains (HPDDG) on rumen degradability, dry matter intake, milk production, and milk composition. Sixteen lactating Holstein cows (12 multiparous and 4 primiparous) averaging 80 +/- 14 d in milk were randomly assigned to 1 of 2 dietary treatments in a 2 x 2 crossover design. A portion of forage and all soy-based protein in the control diet were replaced by HPDDG (20% dry matter). Milk production and dry matter intake were recorded daily and averaged for d 19 to 21 of each 21-d period. Milk samples were collected on d 20 to 21 of each period. Milk yield increased with the inclusion of HPDDG (33.4 vs. 31.6 +/- 2.13 kg/d), and 3.5% FCM was higher for the ration containing HPDDG (36.3 vs. 33.1 +/- 2.24 kg/d). Percentage protein was not affected by treatment (average 3.04 +/- 0.08%), but protein yield increased with inclusion of HPDDG (0.95 to 1.00 +/- 0.05 kg/d). Milk fat concentration was not different between treatments (average 3.95 +/- 0.20%), but fat yield increased for the ration containing HPDDG (1.35 vs. 1.21 +/- 0.09 kg/d). Dry matter intake was not affected and averaged 21.9 +/- 0.80 kg across treatments. Because of greater milk production, feed conversion was improved by the inclusion of HPDDG (1.47 to 1.73 +/- 0.09). Milk urea N was greater for the HPDDG ration than the control (14.5 vs. 12.8 +/- 0.67 mg/dL). This research suggests that HPDDG may effectively replace soy-based protein in lactating dairy cow diets. PMID:19448023

  11. A Short History of Electrical Communication.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    Electrical communication progressed rapidly after Samuel Morse demonstrated the telegraph in 1838. Western Union completed the first transcontinental telegraph line in 1861. Five years later the first transoceanic cable was laid. In 1875 A.G. Bell transmitted the first complete sentence heard over wire, and the first Bell telephone company was…

  12. Identifying High Extension Communicators

    ERIC Educational Resources Information Center

    Lionberger, Herbert F.; Pope, LaVern

    1978-01-01

    Reports results of a survey of social science faculty at the University of Missouri-Columbia to find the extent to which they engaged in communicating information to the public through university extension, with implications for changes in the university rewards system. (MF)

  13. When the facts are just not enough: credibly communicating about risk is riskier when emotions run high and time is short.

    PubMed

    Reynolds, Barbara J

    2011-07-15

    When discussing risk with people, commonly subject matter experts believe that conveying the facts will be enough to allow people to assess a risk and respond rationally to that risk. Because of this expectation, experts often become exasperated by the seemingly illogical way people assess personal risk and choose to manage that risk. In crisis situations when the risk information is less defined and choices must be made within impossible time constraints, the thought processes may be even more susceptible to faulty heuristics. Understanding the perception of risk is essential to understanding why the public becomes more or less upset by events. This article explores the psychological underpinnings of risk assessment within emotionally laden events and the risk communication practices that may facilitate subject matter experts to provide the facts in a manner so they can be more certain those facts are being heard. Source credibility is foundational to risk communication practices. The public meeting is one example in which these best practices can be exercised. Risks are risky because risk perceptions differ and the psychosocial environment in which risk is discussed complicates making risk decisions. Experts who want to influence the actions of the public related to a threat or risk should understand that decisions often involve emotional as well as logical components. The media and other social entities will also influence the risk context. The Center for Disease Control and Prevention's crisis and emergency-risk communication (CERC) principles are intended to increase credibility and recognize emotional components of an event. During a risk event, CERC works to calm emotions and increase trust which can help people apply the expertise being offered by response officials. PMID:21034761

  14. When the facts are just not enough: Credibly communicating about risk is riskier when emotions run high and time is short

    SciTech Connect

    Reynolds, Barbara J.

    2011-07-15

    When discussing risk with people, commonly subject matter experts believe that conveying the facts will be enough to allow people to assess a risk and respond rationally to that risk. Because of this expectation, experts often become exasperated by the seemingly illogical way people assess personal risk and choose to manage that risk. In crisis situations when the risk information is less defined and choices must be made within impossible time constraints, the thought processes may be even more susceptible to faulty heuristics. Understanding the perception of risk is essential to understanding why the public becomes more or less upset by events. This article explores the psychological underpinnings of risk assessment within emotionally laden events and the risk communication practices that may facilitate subject matter experts to provide the facts in a manner so they can be more certain those facts are being heard. Source credibility is foundational to risk communication practices. The public meeting is one example in which these best practices can be exercised. Risks are risky because risk perceptions differ and the psychosocial environment in which risk is discussed complicates making risk decisions. Experts who want to influence the actions of the public related to a threat or risk should understand that decisions often involve emotional as well as logical components. The media and other social entities will also influence the risk context. The Center for Disease Control and Prevention's crisis and emergency-risk communication (CERC) principles are intended to increase credibility and recognize emotional components of an event. During a risk event, CERC works to calm emotions and increase trust which can help people apply the expertise being offered by response officials.

  15. RF propagation in short-range sensor communications

    NASA Astrophysics Data System (ADS)

    Dapper, Mark; Wells, Jeffrey S.; Schwallie, Tony; Huon, Leak

    2003-09-01

    Short-range RF propagation models with antenna elements placed at or near the earth's surface often fail to accurately predict path loss. Adequate mathematical models can be developed and validated to ensure deployed communication systems maintain link closure. Specifically, Unattended Ground Sensor (UGS) systems are deployed to be physically undetected, that is, the units are frequently buried with the antenna extended above earth's surface. This paper reviews the physical effects that determine propagation loss and synthesizes a mathematical model to predict this loss. These predictions are compared to real world propagation measurements in both open fields and in dense foliage for ranges up to 500m.

  16. Short communication: Quantification of carbohydrates in whey permeate products using high-performance anion-exchange chromatography with pulsed amperometric detection

    PubMed Central

    Lee, Hyeyoung; de MeloSilva, Vitor Luiz; Liu, Yan

    2016-01-01

    A method was developed for the characterization and quantification of the disaccharide lactose and 3 major bovine milk oligosaccharides (BMO) in dairy streams. Based on high-performance anion-exchange chromatography-pulsed amperometric detection (HPAE-PAD), this method is advantageous because it requires minimal sample preparation and achieves good chromatographic separation of oligosaccharide isomers within 30 min. The linear dynamic range and limit of detection were 0.1 to 10 mg/L and 0.03 to 0.22 mg/L, respectively. Mean recoveries of the BMO were excellent and ranged from 98.4 to 100.4%. Without complicated sample preparation procedures, this HPAE-PAD method measured BMO [3′-sialyllactose (3′SL), 6′-sialyllactose (6′SL), and 6′-sialyllactosamine (6′SLN)] and lactose using a single instrument, therefore increasing the accuracy of the measurement and applicability for the dairy industry. In colostrum whey permeate, 3′SL, 6′SL, and 6′SLN were 94, 29, and 46 mg/L, respectively. This work is the first to demonstrate that some commercial products, currently marketed for supporting a healthy immune system, contain significant amounts of bioactive BMO and therefore, carry additional bioactivities. PMID:26364096

  17. Short communication: Effects of molasses products on productivity and milk fatty acid profile of cows fed diets high in dried distillers grains with solubles.

    PubMed

    Siverson, A; Vargas-Rodriguez, C F; Bradford, B J

    2014-01-01

    Previous research has shown that replacing up to 5% [of dietary dry matter (DM)] corn with cane molasses can partially alleviate milk fat depression when cows are fed high-concentrate, low-fiber rations containing dried distillers grains with solubles. The primary objective of this study was to determine whether dietary molasses alters milk fatty acid (FA) profile or improves solids-corrected milk yield in the context of a more typical lactation diet. A secondary objective was to assess production responses to increasing rumen-degradable protein supply when molasses was fed. Twelve primiparous and 28 multiparous Holstein cows (196 ± 39 d in milk) were blocked by parity and assigned to 4 pens. Pens were randomly allocated to treatment sequence in a 4 × 4 Latin square design, balanced for carryover effects. Treatment periods were 21 d, with 17 d for diet adaptation and 4 d for sample and data collection. Treatments were a control diet, providing 20% dried distillers grains with solubles (DM basis), 35% neutral detergent fiber, 30% starch, and 5% ether extract; a diet with 4.4% cane molasses replacing a portion of the corn grain; a diet with 2.9% molasses supplement containing 32% crude protein on a DM basis; and a diet with 5.8% (DM basis) molasses supplement. Animal-level data were analyzed using mixed models, including the fixed effect of treatment and the random effects of period, pen, period × pen interaction, and cow within pen to recognize pen as the experimental unit. Diets did not alter DM intake, milk production, milk component concentration or yield, feed efficiency (DM intake/milk yield), body weight change, or milk somatic cell count. Milk stearic acid content was increased by the diet containing 5.8% molasses supplement compared with the control diet and the diet containing 2.9% molasses supplement, but the magnitude of the effect was small (12.27, 11.75, and 11.69 ± 0.29 g/100g of FA). Production data revealed a dramatic effect of period on milk fat

  18. Signal-source trackers on Infrared-based Dedicated Short-Range Communication

    NASA Astrophysics Data System (ADS)

    Lu, Po-Wen; Chen, Rongshun

    2010-03-01

    Location-based ITS applications, especially the applications based on Vehicle-to-Vehicle (V2V) communication, require the absolute or relative location information of the communicating objects. GPS receivers are often used to give the absolute locations of the objects. However, the updating rate and the resolution of GPS receivers are not sufficient for neighboring and highly mobile vehicles. This paper renders two designs, a one-dimensional IR signal-source tracker and a two-dimensional IR signal-source tracker, to estimate the location of a communicating target. By analyzing the strength of the received signal, the relative location of the target is identified once the communication data are received. The realized 1D and 2D IR signal-source tracker can give the precise location, where the repeated tests on the 2D tracker show the given locations with low deviation. Since these two tracker designs are realized with the same IR components in the Dedicated Short-Range Communication (DSRC), the communicating devices, the roadside unit (RSU) and the onboard unit (OBU), can use the 1D or 2D tracker design depending on the application to locate each other, and then to control the radiation direction for saving power, to facilitate the completeness of transactions, and to locate vehicles in V2V applications. In this work, the proposed devices are designed, realized and tested. The experimental results show that these two designs are feasible.

  19. Constructing Overlay Networks with Short Paths and Low Communication Cost

    NASA Astrophysics Data System (ADS)

    Makikawa, Fuminori; Tsuchiya, Tatsuhiro; Kikuno, Tohru

    A Peer-To-Peer (P2P) application uses an overlay network which is a virtual network constructed over the physical network. Traditional overlay construction methods do not take physical location of nodes into consideration, resulting in a large amount of redundant traffic. Some proximity-aware construction methods have been proposed to address this problem. These methods typically connect nearby nodes in the physical network. However, as the number of nodes increases, the path length of a route between two distant nodes rapidly increases. To alleviate this problem, we propose a technique which can be incorporated in existing overlay construction methods. The idea behind this technique is to employ long links to directly connect distant nodes. Through simulation experiments, we show that using our proposed technique, networks can achieve small path length and low communication cost while maintaining high resiliency to failures.

  20. ISS Update: High Rate Communications System

    NASA Video Gallery

    ISS Update Commentator Pat Ryan interviews Diego Serna, Communications and Tracking Officer, about the High Rate Communications System. Questions? Ask us on Twitter @NASA_Johnson and include the ha...

  1. Experimental demonstration of ultraviolet pulse broadening in short-range non-line-of-sight communication channels.

    PubMed

    Chen, Gang; Xu, Zhengyuan; Sadler, Brian M

    2010-05-10

    An experimental test-bed using a narrow-pulsed ultraviolet (UV) laser and high-bandwidth photomultiplier tube was set up to characterize pulse broadening effects in short-range non-line-of-sight (NLOS) scattering communication channels. Pulse broadening is reported as a function of the transmitter elevation angle, transmitter beam angle, receiver elevation angle, receiver field-of-view, and transmitter-receiver distance. The results provide insight into the channel bandwidth and achievable communication data rate. PMID:20588903

  2. Neural Processing of Short-Term Recurrence in Songbird Vocal Communication

    PubMed Central

    Beckers, Gabriël J. L.; Gahr, Manfred

    2010-01-01

    Background Many situations involving animal communication are dominated by recurring, stereotyped signals. How do receivers optimally distinguish between frequently recurring signals and novel ones? Cortical auditory systems are known to be pre-attentively sensitive to short-term delivery statistics of artificial stimuli, but it is unknown if this phenomenon extends to the level of behaviorally relevant delivery patterns, such as those used during communication. Methodology/Principal Findings We recorded and analyzed complete auditory scenes of spontaneously communicating zebra finch (Taeniopygia guttata) pairs over a week-long period, and show that they can produce tens of thousands of short-range contact calls per day. Individual calls recur at time scales (median interval 1.5 s) matching those at which mammalian sensory systems are sensitive to recent stimulus history. Next, we presented to anesthetized birds sequences of frequently recurring calls interspersed with rare ones, and recorded, in parallel, action and local field potential responses in the medio-caudal auditory forebrain at 32 unique sites. Variation in call recurrence rate over natural ranges leads to widespread and significant modulation in strength of neural responses. Such modulation is highly call-specific in secondary auditory areas, but not in the main thalamo-recipient, primary auditory area. Conclusions/Significance Our results support the hypothesis that pre-attentive neural sensitivity to short-term stimulus recurrence is involved in the analysis of auditory scenes at the level of delivery patterns of meaningful sounds. This may enable birds to efficiently and automatically distinguish frequently recurring vocalizations from other events in their auditory scene. PMID:20567499

  3. A high temperature superconductivity communications flight experiment

    NASA Technical Reports Server (NTRS)

    Ngo, P.; Krishen, K.; Arndt, D.; Raffoul, G.; Karasack, V.; Bhasin, K.; Leonard, R.

    1992-01-01

    The proposed high temperature superconductivity (HTSC) millimeter-wave communications flight experiment from the payload bay of the Space Shuttle Orbiter to the Advanced Communications Technology Satellite (ACTS) in geosynchronous orbit is described. The experiment will use a Ka-band HTSC phased array antenna and front-end electronics to receive a downlink communications signal from the ACTS. The discussion covers the system configuration, a description of the ground equipment, the spacecraft receiver, link performance, thermal loading, and the superconducting antenna array.

  4. Systems and methods for short range RF communication

    NASA Technical Reports Server (NTRS)

    Ross, John Anderson Fergus (Inventor); Tomlinson, Harold Woodruff (Inventor); Sexton, Daniel White (Inventor); Hershey, John Erik (Inventor); DeCristofaro, Richard Anthony (Inventor)

    2012-01-01

    A method transmitting a message over at least one of a plurality of channels of a communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of channels. The characteristics of the jamming pulses in the at least one of the plurality of channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses.

  5. Short range RF communication for jet engine control

    NASA Technical Reports Server (NTRS)

    Sexton, Daniel White (Inventor); Hershey, John Erik (Inventor)

    2007-01-01

    A method transmitting a message over at least one of a plurality of radio frequency (RF) channels of an RF communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of RF channels. The characteristics of the jamming pulses in the at least one of the plurality of RF channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of RF channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses.

  6. High performance computing and communications program

    NASA Technical Reports Server (NTRS)

    Holcomb, Lee

    1992-01-01

    A review of the High Performance Computing and Communications (HPCC) program is provided in vugraph format. The goals and objectives of this federal program are as follows: extend U.S. leadership in high performance computing and computer communications; disseminate the technologies to speed innovation and to serve national goals; and spur gains in industrial competitiveness by making high performance computing integral to design and production.

  7. Short signalling distances make plant communication a soliloquy.

    PubMed

    Heil, Martin; Adame-Álvarez, Rosa M

    2010-12-23

    Plants respond to attack by herbivores or pathogens with the release of volatile organic compounds. Neighbouring plants can receive these volatiles and consecutively induce their own defence arsenal. This 'plant communication', however, appears counterintuitive when it benefits independent and genetically unrelated receivers, which may compete with the emitter. As a solution to this problem, a role for volatile compounds in within-plant signalling has been predicted. We used wild-type lima bean (Phaseolus lunatus) to quantify under field conditions the distances over which volatile signals move, and thereby determine whether these cues will mainly trigger resistance in other parts of the same plant or in independent plants. Independent receiver plants exhibited airborne resistance to herbivores or pathogens at maximum distances of 50 cm from a resistance-expressing emitter. In undisturbed clusters of lima bean, over 80 per cent of all leaves that were located around a single leaf at this distance were other leaves of the same plant, whereas this percentage dropped below 50 per cent at larger distances. Under natural conditions, resistance-inducing volatiles of lima bean move over distances at which most leaves that can receive the signal still belong to the same plant. PMID:20554558

  8. Performance of short-range non-line-of-sight LED-based ultraviolet communication receivers.

    PubMed

    He, Qunfeng; Xu, Zhengyuan; Sadler, Brian M

    2010-06-01

    Utilizing an empirical path loss model proposed in the first paper of a two-part series, the bit error rate performance of short-range non-line-of-sight ultraviolet communication receivers is analyzed. Typical photodetector models and modulation formats are considered. Our results provide semi-analytical prediction of the achievable communication performance as a function of system and channel parameters, and serve as a basis for system design. PMID:20588347

  9. Spacecraft design project: High latitude communications satellite

    NASA Technical Reports Server (NTRS)

    Josefson, Carl; Myers, Jack; Cloutier, Mike; Paluszek, Steve; Michael, Gerry; Hunter, Dan; Sakoda, Dan; Walters, Wes; Johnson, Dennis; Bauer, Terry

    1989-01-01

    The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage.

  10. Acoustic communication in two freshwater gobies: ambient noise and short-range propagation in shallow streams.

    PubMed

    Lugli, M; Fine, M L

    2003-07-01

    Noise is an important theoretical constraint on the evolution of signal form and sensory performance. In order to determine environmental constraints on the communication of two freshwater gobies Padogobius martensii and Gobius nigricans, numerous noise spectra were measured from quiet areas and ones adjacent to waterfalls and rapids in two shallow stony streams. Propagation of goby sounds and waterfall noise was also measured. A quiet window around 100 Hz is present in many noise spectra from noisy locations. The window lies between two noise sources, a low-frequency one attributed to turbulence, and a high-frequency one (200-500 Hz) attributed to bubble noise from water breaking the surface. Ambient noise from a waterfall (frequencies below 1 kHz) attenuates as much as 30 dB between 1 and 2 m, after which values are variable without further attenuation (i.e., buried in the noise floor). Similarly, courtship sounds of P. martensii attenuate as much as 30 dB between 5 and 50 cm. Since gobies are known to court in noisy as well as quiet locations in these streams, their acoustic communication system (sounds and auditory system) must be able to cope with short-range propagation dictated by shallow depths and ambient noise in noisy locations. PMID:12880062

  11. Demonstration of micro-projection enabled short-range communication system for 5G.

    PubMed

    Chou, Hsi-Hsir; Tsai, Cheng-Yu

    2016-06-13

    A liquid crystal on silicon (LCoS) based polarization modulated image (PMI) system architecture using red-, green- and blue-based light-emitting diodes (LEDs), which offers simultaneous micro-projection and high-speed data transmission at nearly a gigabit, serving as an alternative short-range communication (SRC) approach for personal communication device (PCD) application in 5G, is proposed and experimentally demonstrated. In order to make the proposed system architecture transparent to the future possible wireless data modulation format, baseband modulation schemes such as multilevel pulse amplitude modulation (M-PAM), M-ary phase shift keying modulation (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) which can be further employed by more advanced multicarrier modulation schemes (such as DMT, OFDM and CAP) were used to investigate the highest possible data transmission rate of the proposed system architecture. The results demonstrated that an aggregative data transmission rate of 892 Mb/s and 900 Mb/s at a BER of 10^(-3) can be achieved by using 16-QAM baseband modulation scheme when data transmission were performed with and without micro-projection simultaneously. PMID:27410326

  12. SHORT COMMUNICATION: An image processing approach to calibration of hydrometers

    NASA Astrophysics Data System (ADS)

    Lorefice, S.; Malengo, A.

    2004-06-01

    The usual method adopted for multipoint calibration of glass hydrometers is based on the measurement of the buoyancy by hydrostatic weighing when the hydrometer is plunged in a reference liquid up to the scale mark to be calibrated. An image processing approach is proposed by the authors to align the relevant scale mark with the reference liquid surface level. The method uses image analysis with a data processing technique and takes into account the perspective error. For this purpose a CCD camera with a pixel matrix of 604H × 576V and a lens of 16 mm focal length were used. High accuracy in the hydrometer reading was obtained as the resulting reading uncertainty was lower than 0.02 mm, about a fifth of the usual figure with the visual reading made by an operator.

  13. Short Communication Molecular conservation of the mammalian leptin protein.

    PubMed

    Gabriel, J E; Lidani, K C F

    2015-01-01

    In this study, we comparatively assessed multiple sequences of the leptin protein from different animal species to establish new insights into conservation degree of biological sequences and evolutionary biology among mammals using computational biology tools. First, amino acid sequences of the leptin protein from Homo sapiens (human, P41159), Sus scrofa (wild pig, Q29406), Felis catus (domestic cat, Q29406), Rattus norvegicus (rat, P50596), and Mus musculus (mouse, P41160) were randomly searched in the high-quality annotated and non-redundant protein sequence database UniProtKB/Swiss-Prot. A dendogram showing the evolutionary relationships among specimens was constructed from the sequences of interest using the Mega 6.0 software with the neighbor-joining method. The resulting tree presenting the evolutionary relationships among specimens inferred from amino acid sequences of the leptin protein in mammals demonstrated 2 main branches: 1 cluster including the rat and mouse species (0.02) and a second cluster containing both wild pig and domestic cat species grouped in a sub-branch (0.04 and 0.06, respectively), linking them to the human sequence (0.08). These findings were reinforced by comparing estimates of evolutionary divergence among leptin sequences analyzed. Based on comparative analyses of multiple sequence alignments in the present study, there was a stronger conservation degree of the leptin protein in evolutionarily close species and several conservative changes along the sequences of interest, revealing information regarding the evolutionary biology among mammals. PMID:25729957

  14. Short communication: Evaluation of nitrogen excretion equations from cattle.

    PubMed

    Johnson, A C B; Reed, K F; Kebreab, E

    2016-09-01

    Nitrogen excretion in dairy manure is a precursor for N2O and NH3 formation in livestock housing, manure storage facilities, and after manure is applied to land. Nitrous oxide is a major contributor to greenhouse gas emissions, and reducing N output from dairy production facilities can reduce the amount of anthropogenic N2O entering the atmosphere. The objective of the study was to conduct a comprehensive evaluation of extant prediction models for N excretion in feces and urine using extensive literature data. A total of 45 N excretion equations were evaluated for lactating cows, heifers, and nonlactating cows and steers. These equations were evaluated with 215 treatment means from 69 published studies collected over 20 yr from 1995 to 2015. Two evaluation methods were used: the root mean square prediction error and the concordance correlation coefficient. Equations constructed using a more rigorous development process fared better than older extant equations. Equations for heifers and nonlactating cows had greater error of prediction compared with equations used for lactating cows. This could be due to limited amount of data available for construction and evaluation of the equations. Urinary N equations had greater prediction errors than other forms of excretion, possibly due to high variability in urinary N excretion and challenges in urine collection. Fecal N equations had low error bias and reached an acceptable level of precision and accuracy. PMID:27320670

  15. Short communication: Reactivity of diacetyl with cleaning and sanitizing agents.

    PubMed

    Rincon-Delgadillo, M I; Lopez-Hernandez, A; Rankin, S A

    2013-01-01

    Diacetyl is used to impart a buttery flavor to numerous food products such as sour cream, cottage cheese, vegetable oil-based spreads, baked goods, and beverages. Recent studies have linked exposure to high concentrations of diacetyl and the onset of bronchiolitis obliterans. Due to the reported risks that diacetyl may pose, many food companies have altered practices to reduce worker exposure to diacetyl, including the use of personal respirators, improved air handling systems, and adequate cleaning practices. Commonly used cleaning and sanitizing agents may be reactive with diacetyl; however, the efficacy of these chemicals has not been studied in detail and remains unclear. The objective of this work was to study the reaction chemistry of diacetyl with common industrial cleaning and sanitizing chemicals. The reactions were assessed at equimolar concentrations and analyzed by gas chromatography-mass spectrometry. Peroxyacetic acid was most reactive with diacetyl (95% reduction in diacetyl), followed by sodium hypochlorite (76% reduction), and hydrogen peroxide (26% reduction). Benzalkonium chloride (BAC) did not react with diacetyl. Acetic acid was detected as the main product of reactions of diacetyl with peroxyacetic acid, sodium hypochlorite, and hydrogen peroxide. 1,1-Dichloro-2-propanone and 1,1,1-trichloropropanone were also identified as volatile reaction products in the sodium hypochlorite reactions. PMID:23063162

  16. Short communication: Macrocyclic lactone residues in butter from Brazilian markets.

    PubMed

    Macedo, Fabio; Marsico, Eliane Teixeira; Conte-Júnior, Carlos Adam; de Almeida Furtado, Leonardo; Brasil, Taila Figueredo; Pereira Netto, Annibal Duarte

    2015-06-01

    Macrocyclic lactones (ML) are commonly used in drug formulations for the treatment of parasites in cattle. In Brazil, except for drugs (or formulations) with long-term (half-life) effects, ML are registered for use in bovines. Indiscriminate use of ML may result in the presence of residues in milk and dairy products due to their lipophilic properties and thermal stability. This study applied a method of liquid chromatography with fluorimetric detection, recently developed and validated for the determination of residues of abamectin, doramectin, ivermectin, and moxidectin in butter. The method was applied to 38 samples of commercial butter purchased in the metropolitan area of Rio de Janeiro, Brazil, between June and September 2013, analyzed in triplicate. Ivermectin was detected in 89.5% of the samples, with concentrations between 0.3 and 119.4 µg/kg; 76.3% of the samples contained doramectin (0.6 to 64.7 µg/kg) and 55.2% contained abamectin (0.7 to 4.5 µg/kg). Most butter samples (76.3%) contained residues of more than 1 ML; however, no residues of moxidectin were detected. The results showed a high incidence of the presence of avermectins in butter samples. Butter is not included in the Brazilian National Plan for Control of Residues and Contaminants in Animal Products. As ML residues concentrate in lipophilic compounds, butter and other fatty dairy products should be screened for the presence of ML residues. PMID:25864054

  17. Short communication: Genetic variation of riboflavin content in bovine milk.

    PubMed

    Poulsen, Nina A; Rybicka, Iga; Larsen, Lotte B; Buitenhuis, Albert J; Larsen, Mette K

    2015-05-01

    Riboflavin (vitamin B2) is an essential water-soluble vitamin; elderly people and adolescents in particular can have poor riboflavin status. In Western diets, milk and dairy products are primary sources of riboflavin, but little is known about the natural variation within and among bovine breeds, and how genetic and environmental factors can affect the riboflavin content in milk. As a part of the Danish-Swedish Milk Genomics Initiative, the aim of the study was to quantify milk riboflavin content using reverse-phase HPLC in 2 major Danish dairy breeds. The results showed substantial interbreed differences in milk riboflavin content. Milk from Danish Jersey cows contained significantly higher levels of riboflavin (1.93mg/L of milk) than milk from Danish Holstein cows (1.40mg/L of milk). Furthermore, genetic analyses revealed high heritabilities in both breeds (0.52 for Danish Holstein and 0.31 for Danish Jersey). A genomic association study found 35 significant single nucleotide polymorphisms (false discovery rate<0.10) to be associated with riboflavin content in milk in Jersey cows (all on BTA14 and BTA17), and 511 significant single nucleotide polymorphisms in Holstein cows spread over 25 different autosomes with BTA13 and BTA14 having the most promising quantitative trait loci. The best candidate gene found within the identified quantitative trait loci was SLC52A3, a riboflavin transporter gene, which was among the significant markers on BTA13 in Holstein cows. PMID:25771056

  18. Short communication: Pasteurization of milk abolishes bovine herpesvirus 4 infectivity.

    PubMed

    Bona, C; Dewals, B; Wiggers, L; Coudijzer, K; Vanderplasschen, A; Gillet, L

    2005-09-01

    Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus highly prevalent in the cattle population that has been isolated from the milk and the serum of healthy infected cows. Several studies reported the sensitivity and the permissiveness of some human cells to BoHV-4 infection. Moreover, our recent study demonstrated that some human cells sensitive but not permissive to BoHV-4 support a persistent infection protecting them from tumor necrosis factor-alpha-induced apoptosis. Together, these observations suggested that BoHV-4 could represent a danger for public health. To evaluate the risk of human infection by BoHV-4 through milk or serum derivatives, we investigated the resistance of BoHV-4 to the mildest thermal treatments usually applied to these products. The results demonstrated that milk pasteurization and thermal decomplementation of serum abolish BoHV-4 infectivity by inactivation of its property to enter permissive cells. Consequently, our results demonstrate that these treatments drastically reduce the risk of human infection by BoHV-4 through treated milk or serum derivatives. PMID:16107396

  19. Short communication: A comparative analysis of recombinant chymosins.

    PubMed

    Vallejo, J A; Ageitos, J M; Poza, M; Villa, T G

    2012-02-01

    The first step in cheesemaking is the milk clotting process, in which κ-caseinolytic enzymes contribute to micelle precipitation. The best enzyme for this purpose is chymosin because of its high degree of specificity toward κ-casein. Although recombinant bovine chymosin is the most frequently used chymosin in the industry, new sources of recombinant chymosin, such as goat, camel, or buffalo, are now available. The present work represents a comparative study of 4 different recombinant chymosins (goat and buffalo chymosins expressed in Pichia pastoris, and bovine and camel chymosin expressed in Aspergillus niger). Recombinant goat chymosin exhibited the best catalytic efficiency compared with the buffalo, bovine, or camel recombinant enzymes. Moreover, recombinant goat chymosin exhibited the best specific proteolytic activity, a wider pH range of action, and a lower glycosylation degree than the other 3 enzymes. In conclusion, we propose that recombinant goat chymosin represents a serious alternative to recombinant bovine chymosin for use in the cheesemaking industry. PMID:22281325

  20. Short communication: Individual cow variation in urinary excretion of phosphorus.

    PubMed

    Løvendahl, Peter; Sehested, Jakob

    2016-06-01

    Some dairy cows excrete large amounts of P through their urine; thus, it was speculated that a genetic defect related to their efficiency in uptake of P or recirculation of P could cause such an effect. This speculation was pursued in a cross sectional study on 139 cows (103 Holstein and 36 Jersey) from an experimental herd using repeated sampling of urine (301 samples) to investigate sources of variation in urinary P concentration (Pu). Urine samples were taken on 6 testing sessions spread over 2 mo. Each sample was obtained by mild manual stimulation of the rear udder escutcheon area. The samples were immediately assayed for pH, stored frozen, and assayed for inorganic P and creatinine. Concentrations of P and creatinine in urine, the ratio of Pu to creatinine, and pH were analyzed using a linear mixed model. The model included fixed effects of breed, parity number, and sampling session. Stage of lactation was fitted as Wilmink-type lactation curves. Random effects included additive polygenic ancestry, permanent animal effects, and residual. The distribution of Pu approximated normality except for a single sample with very high Pu and very low pH. This sample came from a cow diagnosed independently with ketosis. For the remaining samples, it was shown that Pu has low to moderate heritability (0.12) and is only moderately repeatable (0.21). Based on a small data set, it is tentatively concluded that individual differences between cows exist in their Pu, and individual differences presumably result from genetic differences. However, it remains unclear if cows with genetically lower or higher Pu will perform better on a low-P diet. PMID:26995137

  1. Short-Form Versions of the Spanish MacArthur-Bates Communicative Development Inventories

    ERIC Educational Resources Information Center

    Jackson-Maldonodo, Donna; Marchman, Virginia A.; Fernald, Lia C. H.

    2013-01-01

    The Spanish-language MacArthur-Bates Communicative Development Inventories (S-CDIs) are well-established parent report tools for assessing the language development of Spanish-speaking children under 3 years. Here, we introduce the short-form versions of the S-CDIs (SFI and SFII), offered as alternatives to the long forms for screening purposes or…

  2. Technology Development for High Efficiency Optical Communications

    NASA Technical Reports Server (NTRS)

    Farr, William H.

    2012-01-01

    Deep space optical communications is a significantly more challenging operational domain than near Earth space optical communications, primarily due to effects resulting from the vastly increased range between transmitter and receiver. The NASA Game Changing Development Program Deep Space Optical Communications Project is developing four key technologies for the implementation of a high efficiency telecommunications system that will enable greater than 10X the data rate of a state-of-the-art deep space RF system (Ka-band) for similar transceiver mass and power burden on the spacecraft. These technologies are a low mass spacecraft disturbance isolation assembly, a flight qualified photon counting detector array, a high efficiency flight laser amplifier and a high efficiency photon counting detector array for the ground-based receiver.

  3. Preprocessing communication unit (PCU) with short message service (SMS) communication channels for AVL tracking

    NASA Astrophysics Data System (ADS)

    Young, Andrew S.; Skobla, Joseph

    2003-08-01

    The Preprocessing GPS - SMS Communication Unit (PCU) is a mobile tracking device used within AVL tracking systems for determining the location of vehicles. It was designed primarily to utilize the SMS service of the GSM network for communicating. The use of SMS messages is part of an effort aimed at providing a cost effective alternative for tracking the location of vehicles. Its primary function is to send information about user location across a GSM network to a Central Base Station (CBS) from which assets are being tracked. Though SMS is the main bearer, the unit is also capable of using Circuit Switch Data Service (CSD) to send and receive data from the Base Station (BS). The PCU was developed as a small hardware unit based on the Microchip microcontroller, with a multiplexer switching two RS 232 serial inputs. One input is dedicated to the GPS receiver and the second one to the wireless modem.

  4. Monolithically integrated quantum dot optical modulator with Semiconductor optical amplifier for short-range optical communications

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

    2015-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed. Broadband QD optical gain material was used to achieve Gbps-order high-speed optical data transmission, and an optical gain change as high as approximately 6-7 dB was obtained with a low OGM voltage of 2.0 V. Loss of optical power due to insertion of the device was also effectively compensated for by the SOA section. Furthermore, it was confirmed that the QD-OGM/SOA device helped achieve 6.0-Gbps error-free optical data transmission over a 2.0-km-long photonic crystal fiber. We also successfully demonstrated generation of Gbps-order, high-speed, and error-free optical signals in the >5.5-THz broadband optical frequency bandwidth larger than the C-band. These results suggest that the developed monolithically integrated QD-OGM/SOA device will be an advantageous and compact means of increasing the usable optical frequency channels for short-reach communications.

  5. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  6. High Performance Computing and Communications Panel Report.

    ERIC Educational Resources Information Center

    President's Council of Advisors on Science and Technology, Washington, DC.

    This report offers advice on the strengths and weaknesses of the High Performance Computing and Communications (HPCC) initiative, one of five presidential initiatives launched in 1992 and coordinated by the Federal Coordinating Council for Science, Engineering, and Technology. The HPCC program has the following objectives: (1) to extend U.S.…

  7. Intravehicular, Short- and Long-Range Communication Information Fusion for Providing Safe Speed Warnings.

    PubMed

    Jiménez, Felipe; Naranjo, Jose Eugenio; Serradilla, Francisco; Pérez, Elisa; Hernández, María Jose; Ruiz, Trinidad; Anaya, José Javier; Díaz, Alberto

    2016-01-01

    Inappropriate speed is a relevant concurrent factor in many traffic accidents. Moreover, in recent years, traffic accidents numbers in Spain have fallen sharply, but this reduction has not been so significant on single carriageway roads. These infrastructures have less equipment than high-capacity roads, therefore measures to reduce accidents on them should be implemented in vehicles. This article describes the development and analysis of the impact on the driver of a warning system for the safe speed on each road section in terms of geometry, the presence of traffic jams, weather conditions, type of vehicle and actual driving conditions. This system is based on an application for smartphones and includes knowledge of the vehicle position via Ground Positioning System (GPS), access to intravehicular information from onboard sensors through the Controller Area Network (CAN) bus, vehicle data entry by the driver, access to roadside information (short-range communications) and access to a centralized server with information about the road in the current and following sections of the route (long-range communications). Using this information, the system calculates the safe speed, recommends the appropriate speed in advance in the following sections and provides warnings to the driver. Finally, data are sent from vehicles to a server to generate new information to disseminate to other users or to supervise drivers' behaviour. Tests in a driving simulator have been used to define the system warnings and Human Machine Interface (HMI) and final tests have been performed on real roads in order to analyze the effect of the system on driver behavior. PMID:26805839

  8. Intravehicular, Short- and Long-Range Communication Information Fusion for Providing Safe Speed Warnings

    PubMed Central

    Jiménez, Felipe; Naranjo, Jose Eugenio; Serradilla, Francisco; Pérez, Elisa; Hernández, María Jose; Ruiz, Trinidad; Anaya, José Javier; Díaz, Alberto

    2016-01-01

    Inappropriate speed is a relevant concurrent factor in many traffic accidents. Moreover, in recent years, traffic accidents numbers in Spain have fallen sharply, but this reduction has not been so significant on single carriageway roads. These infrastructures have less equipment than high-capacity roads, therefore measures to reduce accidents on them should be implemented in vehicles. This article describes the development and analysis of the impact on the driver of a warning system for the safe speed on each road section in terms of geometry, the presence of traffic jams, weather conditions, type of vehicle and actual driving conditions. This system is based on an application for smartphones and includes knowledge of the vehicle position via Ground Positioning System (GPS), access to intravehicular information from onboard sensors through the Controller Area Network (CAN) bus, vehicle data entry by the driver, access to roadside information (short-range communications) and access to a centralized server with information about the road in the current and following sections of the route (long-range communications). Using this information, the system calculates the safe speed, recommends the appropriate speed in advance in the following sections and provides warnings to the driver. Finally, data are sent from vehicles to a server to generate new information to disseminate to other users or to supervise drivers’ behaviour. Tests in a driving simulator have been used to define the system warnings and Human Machine Interface (HMI) and final tests have been performed on real roads in order to analyze the effect of the system on driver behavior. PMID:26805839

  9. Rectangular Microstirp Patch Antenna Design at THz Frequency for Short Distance Wireless Communication Systems

    NASA Astrophysics Data System (ADS)

    Sharma, Aditi; Singh, G.

    2009-01-01

    In this paper, we have presented the simulation results of a rectangular microstrip patch antenna at terahertz (THz) frequency ranging from 0.7 to 0.85 THz. THz electromagnetic wave can permit more densely packed communication links with increased security of communication transmission. The simulated results such as gain, radiation efficiency and 10 dB impedance bandwidth of rectangular microstrip patch antenna at THz frequencies without shorting post configuration are 3.497 dB, 55.71% and 17.76%, respectively, whereas with shorting post configuration, corresponding parameters are 3.502 dB, 55.88% and 17.27%. The simulation has been performed by using CST Microwave Studio, which is a commercially available electromagnetic simulator based on the method of finite difference time domain technique.

  10. Apparatus of short baseline centrimetric wave radiointerferometer with cable communication lines for astrophysical research

    NASA Astrophysics Data System (ADS)

    Alekseyev, V. A.; Kryukov, A. Y.; Lipatov, B. N.; Sizov, A. S.

    1984-09-01

    Using the very-long-baseline astrometric radiointerferometer at the Scientific-Research Institute of Radiophysics as a model and reference, a short-baseline decimetric-wave radiointerferometer with scale communication lines between antennas was developed and designed for measuring the modulus of the visibility function of radioemission sources. Operation of this radiointerferometer was checked first in the laboratory and then in the field against several extraterrestrial radioemission sources (3C 273, Cygnus-A). Although the peak of the interferometer response curve is generally a function of delay time and interference frequency, here the correlational envelope of received radioemission represents the radiation pattern with respect to time delay and is such that it increases the noise immunity of the system by suppressing wideband correlational noise at the instant of observation. Fourier analysis of interference fluctuations with high spectral resolution in real time does, furthermore, facilitate discrimination of the useful signal from correlational noise. It is also possible here to attain very long periods of coherent pickup, necessary for measurement of power fluxes from sources which are regarded as point sources relative to the baseline.

  11. Meteor scatter radio communication at high latitudes

    NASA Astrophysics Data System (ADS)

    Cannon, P. S.; Dickson, A. H.; Armstrong, M. H.

    1985-11-01

    A brief historical and physical description of the meteor burst communications (MBC) technique is given together with a discussion of the advantages of very high frequency MBC, with respect to conventional high frequency communication, when used at high latitudes. A recently deployed high latitude MBC propagation experiment, between Bodo in Norway and Wick in Scotland (UK) is described and some of the early data gathered at frequencies close to 40 MHz and 70 MHz is presented. A theoretical description of the effects of Polarisation Rotation in a linearly polarised MBC system is developed and it is shown that at 40 MHz Polarisation Rotation, due to excess D-region ionization may cause the system performance to differ from its ambient level. Corroborative experimental results, over a temperature latitude path, are presented. Based upon the early high latitude experimental results and on the theoretical calculations, it is suggested that frequencies close to 40 MHz, in common use in atemperate latitude linearly polarised MBC systems, are too low for high latitude operation.

  12. High-Capacity Communications from Martian Distances

    NASA Technical Reports Server (NTRS)

    Williams, W. Dan; Collins, Michael; Hodges, Richard; Orr, Richard S.; Sands, O. Scott; Schuchman, Leonard; Vyas, Hemali

    2007-01-01

    High capacity communications from Martian distances, required for the envisioned human exploration and desirable for data-intensive science missions, is challenging. NASA s Deep Space Network currently requires large antennas to close RF telemetry links operating at kilobit-per-second data rates. To accommodate higher rate communications, NASA is considering means to achieve greater effective aperture at its ground stations. This report, focusing on the return link from Mars to Earth, demonstrates that without excessive research and development expenditure, operational Mars-to-Earth RF communications systems can achieve data rates up to 1 Gbps by 2020 using technology that today is at technology readiness level (TRL) 4-5. Advanced technology to achieve the needed increase in spacecraft power and transmit aperture is feasible at an only moderate increase in spacecraft mass and technology risk. In addition, both power-efficient, near-capacity coding and modulation and greater aperture from the DSN array will be required. In accord with these results and conclusions, investment in the following technologies is recommended:(1) lightweight (1 kg/sq m density) spacecraft antenna systems; (2) a Ka-band receive ground array consisting of relatively small (10-15 m) antennas; (3) coding and modulation technology that reduces spacecraft power by at least 3 dB; and (4) efficient generation of kilowatt-level spacecraft RF power.

  13. Small Signaling Peptides in Arabidopsis Development: How Cells Communicate Over a Short Distance

    PubMed Central

    Murphy, Evan; Smith, Stephanie; De Smet, Ive

    2012-01-01

    To sustain plants’ postembryonic growth and development in a structure of cells fixed in cell walls, a tightly controlled short distance cell–cell communication is required. The focus on phytohormones, such as auxin, has historically overshadowed the importance of small peptide signals, but it is becoming clear that secreted peptide signals are important in cell–cell communication to coordinate and integrate cellular functions. However, of the more than 1000 potential secreted peptides, so far only very few have been functionally characterized or matched to a receptor. Here, we will describe our current knowledge on how small peptide signals can be identified, how they are modified and processed, which roles they play in Arabidopsis thaliana development, and through which receptors they act. PMID:22932676

  14. Efficient High Performance Collective Communication for Distributed Memory Environments

    ERIC Educational Resources Information Center

    Ali, Qasim

    2009-01-01

    Collective communication allows efficient communication and synchronization among a collection of processes, unlike point-to-point communication that only involves a pair of communicating processes. Achieving high performance for both kernels and full-scale applications running on a distributed memory system requires an efficient implementation of…

  15. Beam divergence changing mechanism for short-range inter-unmanned aerial vehicle optical communications.

    PubMed

    Heng, Kiang Huat; Zhong, Wen-De; Cheng, Tee Hiang; Liu, Ning; He, Yingjie

    2009-03-10

    The problems associated with using a single fixed beam divergence for short-range inter-unmanned aerial vehicle free-space optical communications are discussed. To overcome the problems, a beam divergence changing mechanism is proposed. Four different methods are then proposed to implement the beam divergence changing mechanism. The performance of these methods is evaluated in terms of transmission distance under adverse weather conditions. The results show that the performance is greatly improved when the beam divergence changing mechanism is used. PMID:19277090

  16. High accuracy in short ISS missions

    NASA Astrophysics Data System (ADS)

    Rüeger, J. M.

    1986-06-01

    Traditionally Inertial Surveying Systems ( ISS) are used for missions of 30 km to 100 km length. Today, a new type of ISS application is emanating from an increased need for survey control densification in urban areas often in connection with land information systems or cadastral surveys. The accuracy requirements of urban surveys are usually high. The loss in accuracy caused by the coordinate transfer between IMU and ground marks is investigated and an offsetting system based on electronic tacheometers is proposed. An offsetting system based on a Hewlett-Packard HP 3820A electronic tacheometer has been tested in Sydney (Australia) in connection with a vehicle mounted LITTON Auto-Surveyor System II. On missions over 750 m ( 8 stations, 25 minutes duration, 3.5 minute ZUPT intervals, mean offset distances 9 metres) accuracies of 37 mm (one sigma) in position and 8 mm in elevation were achieved. Some improvements to the LITTON Auto-Surveyor System II are suggested which would improve the accuracies even further.

  17. Public Speaking or Interpersonal Communication: The Perspective of the High Communication Apprehension Student.

    ERIC Educational Resources Information Center

    Pearson, Judy C.; Yoder, Donald D.

    Of 782 undergraduate students enrolled in either interpersonal communication or public speaking courses, the 125 students scoring high in communication apprehension were retested upon completion of the courses and analyzed for their responses to a student attitudes survey. Significantly greater numbers of the high communication apprehensive (HCA)…

  18. German Deaf People Using Text Communication: Short Message Service, TTY, Relay Services, Fax, and E-Mail

    ERIC Educational Resources Information Center

    Power, Des; Power, Mary R.; Rehling, Bernd

    2007-01-01

    An online survey of German deaf people demonstrated that they use text communication through Short Message Service (SMS), e-mail, fax, and telephone typewriters (TTY) to communicate within communities of deaf and hearing people. SMS is used most, with more than 96% of respondents having access to a mobile phone. Most use is intrinsic and directed…

  19. Introduction to nanotechnology: a short course for high school students

    NASA Astrophysics Data System (ADS)

    Markin, Alexey V.

    2016-04-01

    This report devoted to presenting results of development and implementation of a short course (4 hours) entitled "Introduction to Nanotechnology" that was specially designed for familiarizing high school students with nanomaterials and nanotechnology. The course contains introduction to nanotechnology, essential definitions, short overview of history, descriptions for various examples of nanomaterials and their classifications, performing demonstration experiments. All these parts of the course are briefly analyzed from pedagogical effectiveness point of view. Finally, results of course testing, problems and perspectives of nano-oriented education at high school are also discussed shortly.

  20. Fiber Laser Front Ends for High Energy, Short Pulse Lasers

    SciTech Connect

    Dawson, J; Messerly, M; Phan, H; Siders, C; Beach, R; Barty, C

    2007-06-21

    We are developing a fiber laser system for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal for these systems as they are highly reliable and enable long term stable operation.

  1. Advanced short haul aircraft for high density markets

    NASA Technical Reports Server (NTRS)

    Galloway, T. L.

    1977-01-01

    The short haul (less than 500 miles) passenger enplanements represent about 50% of the total domestic enplanements. These can be distinguished by the annual passenger flow for a given city pair and classified into low, medium and high densiy markets. NASA studies have investigated various advanced short haul aircraft concepts that have potential application in these three market areas. Although advanced operational techniques impact all market densities, advanced vehicle design concepts such as RTOL, STOL and VTOL have the largest impact in the high density markets. This paper summarizes the results of NASA sponsored high density short haul air transportation systems studies and briefly reviews NASA sponsored advanced VTOL conceptual aircraft design studies. Trends in vehicle characteristics and operational requirements will be indicated in addition to economic suitability and impact on the community.

  2. A Low-Cost Cooperative Strategy for Cellular Controlled Short-Range Communication Systems

    NASA Astrophysics Data System (ADS)

    Han, Han; Wang, Hao; Lin, Xiaokang

    This letter is concerned with cellular controlled short-range communication (CCSRC) systems, which can provide a significant performance gain over the traditional cellular systems as shown in the literature. However, to obtain such a gain, CCSRC systems need perfect channel state information (CSI) of all users and the complexity of setting up the optimal cooperative clusters is factorial with respect to the number of potentially cooperative users, which is very unrealistic in practical systems. To solve this problem, we propose a novel cooperative strategy, where CCSRC systems only need the distances between all user pairs and the complexity of setting up the cooperative clusters is relatively low. Simulation results show that the performance of the proposed strategy is close to optimal.

  3. Applications of High Technology to Communication Instruction.

    ERIC Educational Resources Information Center

    Behnke, Ralph R.; O'Hair, H. Dan

    1984-01-01

    Discusses classroom design and uses of interactive media. Covers the design of public speaking/interpersonal/small group communication classrooms, the simulation laboratory, the communication effectiveness trainer (ComET system), audience response systems, speech evaluation using computers, and system design considerations. (PD)

  4. An Energy-Harvesting Wireless-Interface SoC for Short-Range Data Communication

    NASA Astrophysics Data System (ADS)

    Mikami, Shinji; Matsuno, Tetsuro; Miyama, Masayuki; Kawaguchi, Hiroshi; Yoshimoto, Masahiko; Ono, Hiroaki

    This paper describes design and verification of a wireless-interface SoC (system-on-a-chip) for a wireless battery-less mouse with short-range data-communication capability. The SoC comprises an RF transmitter and microcontroller. The SoC, which is powered by an electric generator that exploits gyration energy by dragging the mouse, was fabricated using a TSMC 0.18-um CMOS process. The features of the SoC are the adoption of a simple FSK modulation scheme, single-end configuration on the RF transmitter, and specific microcontroller design for mouse operation. We verified that the RF transmitter can make data communication within a 1-m range at 2.17 mW, and the microcontroller consumes 0.03 mW at 1 MHz, which exhibits that the total power consumption is 2.2 mW. This is sufficiently low for the SoC to operate with energy harvesting.

  5. Visible light communication in dynamic environment using image/high-speed communication hybrid sensor

    NASA Astrophysics Data System (ADS)

    Maeno, Keita; Panahpour Tehrani, Mehrdad; Fujii, Toshiaki; Okada, Hiraku; Yamazato, Takaya; Tanimoto, Masayuki; Yendo, Tomohiro

    2012-01-01

    Visible Light Communication (VLC) is a wireless communication method using LEDs. LEDs can respond in high-speed and VLC uses this characteristics. In VLC researches, there are two types of receivers mainly, one is photodiode receiver and the other is high-speed camera. A photodiode receiver can communicate in high-speed and has high transmission rate because of its high-speed response. A high-speed camera can detect and track the transmitter easily because it is not necessary to move the camera. In this paper, we use a hybrid sensor designed for VLC which has advantages of both photodiode and high-speed camera, that is, high transmission rate and easy detecting of the transmitter. The light receiving section of the hybrid sensor consists of communication pixels and video pixels, which realizes the advantages. This hybrid sensor can communicate in static environment in previous research. However in dynamic environment, high-speed tracking of the transmitter is essential for communication. So, we realize the high-speed tracking of the transmitter by using the information of the communication pixels. Experimental results show the possibility of communication in dynamic environment.

  6. Spontaneous Radiation Emission from Short, High Field Strength Insertion Devices

    SciTech Connect

    Geoffrey Krafft

    2005-09-15

    Since the earliest papers on undulaters were published, it has been known how to calculate the spontaneous emission spectrum from ''short'' undulaters when the magnetic field strength parameter is small compared to unity, or in ''single'' frequency sinusoidal undulaters where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulater. Fewer general results have been obtained in the case where the insertion device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the insertion device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented for calculating the radiation spectrum for short, high-field insertion devices. It is used to calculate the emission from some insertion device designs of recent interest.

  7. Assessment of highly active dune mobility in the medium, short and very short term

    NASA Astrophysics Data System (ADS)

    Navarro, Marina; Muñoz-Pérez, Juan J.; Román-Sierra, Jorge; Tsoar, Haim; Rodríguez, Inmaculada; Gómez-Pina, Gregorio

    2011-06-01

    Dune activity or stability has usually been studied over long time periods; however, this may not reflect changes that occur in the short term, especially for highly active dunefields. Extreme wind conditions that are generated near the Strait of Gibraltar (SW Spain) have given rise to the transgressive Valdevaqueros dunefield. The current work focuses on analyzing the sand drift potential and the evolution of the dune profile in the medium term (months), the short term (days) and the very short term (hours). Topographic data, which were collected with a differential GPS, were interpreted from reconstructed empirical orthogonal functions (EOF). The results showed that generally the dune profile presented shifting morphologies, especially around the crest and brink, and a trend towards migration to a gentler steady state. As a result, the leeward side adopted continuous slope variations during the different survey periods, whereas the windward slope did not undergo any significant change. Lateral and vertical displacements were analyzed during a severe easterly sandstorm, when the dune brink experienced an advance migration rate of 1.75 m in 24 h. Sand transport rates of 25.5-36.5 m 3 m - 1 month - 1 , 22.52 m 3 m - 1 day - 1 and 0.93 m 3 m - 1 h - 1 were measured for the medium term, short term and very short term, respectively. These values were compared to the theoretical sand transport rate for Valdevaqueros dune, based on the classic Bagnold equation as well other more recent formulae, to obtain a ratio between the real and the theoretical rates for each study period. These results together with the sand drift potential (up to 10,000 vector units) demonstrate that Valdevaqueros (Tarifa) is a dunefield with one of the highest sand transport capacities in Europe.

  8. Research with high-power short-wavelength lasers.

    PubMed

    Holzrichter, J F; Campbell, E M; Lindl, J D; Storm, E

    1985-09-13

    Three high-temperature, high-density experments were conducted recently with the 10-terawatt, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. The experiments demonstrated successful solutions to problems that arose during previous laser-plasma interaction experiments with long-wavelength (greater than 1 micrometer) lasers: (i) large-scale plasmas, with dimensions approaching those needed for high-gain inertial fusion targets, were produced in which potentially deleterious laser-plasma instabilities were collisionally damped; (ii) deuterium-tritium fuel was imploded to a density of 20 grams per cubic centimeter and a pressure of 10(10) atmospheres under the improved laser conditions, and compression conditions (preheating and pressure) were consistent with code calculations that predict efficient (high-gain) burn of a large thermonuclear fuel mass when driven with a large, short-wavelength laser; and (iii) soft x-rays were amplified by a factor of 700 by stimulated emission at 206 and 209 angstroms (62 electron volts) from selenium ions in a laser-generated plasma. These small, short-pulse x-ray sources are 10(10) to 10(11) times brighter than the most powerful x-ray generators and synchrotron sources available today. The plasma conditions for these experiments were made possible by advances in Nd:glass laser technology, in techniques to generate efficiently its short-wavelength harmonics at 0.53, 0.35, and 0.26 micrometers, and in diagnostic and computational modeling. PMID:17753271

  9. 622 Mbps High-speed satellite communication system for WINDS

    NASA Astrophysics Data System (ADS)

    Ogawa, Yasuo; Hashimoto, Yukio; Yoshimura, Naoko; Suzuki, Ryutaro; Gedney, Richard T.; Dollard, Mike

    2006-07-01

    WINDS is the experimental communications satellite currently under joint development by Japanese Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). The high-speed satellite communication system is very effective for quick deployment of high-speed networks economically. The WINDS will realize ultra high-speed networking and demonstrate operability of satellite communication systems in high-speed internet. NICT is now developing high-speed satellite communication system for WINDS. High-speed TDMA burst modem with high performance TPC error correction is underdevelopment. Up to the DAC on the transmitter and from the ADC on the receiver, all modem functions are performed in the digital processing technology. Burst modem has been designed for a user data rate up to 1244 Mbps. NICT is developing the digital terminal as a user interface and a network controller for this earth station. High compatibility with the Internet will be provided.

  10. High-Latitude Communications Satellite (HILACS)

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Naval Postgraduate School in the AE 4871 Advanced Spacecraft Design course designed a communications satellite (HILACS) that will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specific coverage. The satellite orbit is elliptic with perigee at 1204 km in the Southern Hemisphere and an apogee at 14,930 km with 63.4 degrees inclination. Analysis and design of each of the subsystems was done to the extent possible within the constraints of an eleven week quarter and the design and analysis tools available. Work was completed in orbital analysis, the reaction control system, attitude control subsystem, electric power subsystem, telemetry, tracking, and control, thermal control subsystem, and the structures subsystem. The design team consisted of 12 students. Additional support was provided by the Jet Propulsion Laboratory and the Naval Research Laboratory.

  11. Iridium: Global OTH data communications for high altitude scientific ballooning

    NASA Astrophysics Data System (ADS)

    Denney, A.

    beneficial points provided by the Iridium platform include pure global accessibility (as well as polar), cost effectiveness because it is available as a COTS (Commercially Off The Shelf) technology, reliability in that the equipment must operate in extreme conditions (near space), integration and development time into current systems must be minimized. As a bonus Motorola and NAL Research Corporation are developing SBD (Short Burst Data) into the Iridium network. This may lead the way to a global IP (Internet Protocol) node based ballooning platform. The Iridium satellite data modems employ the Iridium Low-Earth Orbit (LEO) satellite network. The scope of this paper is to introduce an OTH communications alternative, albeit not necessarily a primary one, to existing ballooning platforms using COTS based emerging technologies. Design aspects, characteristics, actual flight testing statistics, principles of the Iridium modems and communication paths are described including payload and support instrumentation interfacing. Not limited to high altitude ballooning, the Iridium communications platform opens a new era in remote commanding and data retrieval.

  12. Analyzing the Texas High School Agricultural Communications Curriculum.

    ERIC Educational Resources Information Center

    Montgomery-White, Michelle; Lockaby, Jacqui; Akers, Cindy

    The purpose of this study was to evaluate the agricultural communications curriculum in Texas high schools using perceptions of agriscience teachers (n=145) in Texas high schools. Another intention of the study was to determine perceived abilities of agriscience teachers to teach agricultural communications courses. Answers to questions related to…

  13. TDX: A high-bandwidth crossbar-switched communication paradigm

    SciTech Connect

    Pierce, P.E.; Eilers, D.L.; Schreiber, A.L.

    1994-08-01

    Digital signal processing systems under development today require scalable and reconfigurable high bandwidth communication resources between processing elements. Shared memory architectures require the ability to transfer data from one processor node to another, as well as maintaining data coherency such as provided by the Scalable Coherent Interface (SCI). Signal processing systems that must move large amounts of data between processor nodes, are best served by a communication system that allows reconfigurable streams of data to flow at deterministic rates with minimal overhead. A Time Domain Crossbar (TDX) communication system providing scalable, programmable, high-bandwidth, streaming communication has been developed and is described in this paper.

  14. Dynamic properties of a pulse-pumped fiber laser with a short, high-gain cavity

    NASA Astrophysics Data System (ADS)

    Yang, Chaolin; Guo, Junhong; Wei, Pu; Wan, Hongdan; Xu, Ji; Wang, Jin

    2016-09-01

    We demonstrate a pulsed high-gain all-fiber laser without intracavity modulators, where a short and heavily Erbium-doped fiber is used as the gain medium in a ring cavity. By pulsed-pumping this short high gain cavity and tuning an intracavity variable optical coupler, the laser generates optical pulses with a pulse-width of μs at a repetition rate in the order of kHz down to one-shot operation. Furthermore, dynamic properties of this laser are investigated theoretically based on a traveling-wave-model, in which an adaptive-discrete-grid-finite-difference-method is applied. The simulation results validate the experimental results. The demonstrated pulsed laser is compact, flexible and cost-effective, which will have great potential for applications in all-optical sensing and communication systems.

  15. High-repetition-rate short-pulse gas discharge.

    PubMed

    Tulip, J; Seguin, H; Mace, P N

    1979-09-01

    A high-average-power short-pulse gas discharge is described. This consists of a volume-preionized transverse discharge of the type used in gas lasers driven by a Blumlein energy storage circuit. The Blumlein circuit is fabricated from coaxial cable, is pulse-charged from a high-repetition-rate Marx-bank generator, and is switched by a high-repetition-rate segmented rail gap. The operation of this discharge under conditions typical of rare-gas halide lasers is described. A maximum of 900 pps was obtained, giving a power flow into the discharge of 30 kW. PMID:18699678

  16. Instructional Communications in a Large High School.

    ERIC Educational Resources Information Center

    Kusimo, Patricia S.; Erlandson, David A.

    1983-01-01

    This summary of a study describing the communications of school administrators and teachers and the degree of congruency between principals' and teachers' instructional intentions and students' and teachers' perceptions of classroom events concludes by proposing Rensis Likert's overlapping work groups as a more effective organizational pattern for…

  17. An Outcome Study of Short-Term Communication Training with Married Couples.

    ERIC Educational Resources Information Center

    Epstein, Norman; Jackson, Elizabeth

    1978-01-01

    Compared communication training, interaction insight training, and no treatment for changes in marital verbal interaction and spouses' ratings of each other on the Barrett-Lennard Relationship Inventory. Communication training produced increases in assertive requests. Both treatments reduced disagreement. Communication training produced a decrease…

  18. Visual Communications Studies at Roberto Clemente High School.

    ERIC Educational Resources Information Center

    Karzen, Michael

    1981-01-01

    Roberto Clemente High School in Chicago has an interdisciplinary communications program involving seven subject areas: Graphic Design, Graphic Arts, Photography, Photocomposition, TV Radio/Film, Communications in Spanish, and Latin American Literature. The instructors in these classes form a team. This article is part of a theme issue on career…

  19. Trend on High-speed Power Line Communication Technology

    NASA Astrophysics Data System (ADS)

    Ogawa, Osamu

    High-speed power line communication (PLC) is useful technology to easily build the communication networks, because construction of new infrastructure is not necessary. In Europe and America, PLC has been used for broadband networks since the beginning of 21th century. In Japan, high-speed PLC was deregulated only indoor usage in 2006. Afterward it has been widely used for home area network, LAN in hotels and school buildings and so on. And recently, PLC is greatly concerned as communication technology for smart grid network. In this paper, the author surveys the high-speed PLC technology and its current status.

  20. Short Communication: Atmospheric moisture transport, the bridge between ocean evaporation and Arctic ice melting

    NASA Astrophysics Data System (ADS)

    Gimeno, L.; Vázquez, M.; Nieto, R.; Trigo, R. M.

    2015-06-01

    If we could choose a region where the effects of global warming are likely to be pronounced and considerable, and at the same time one where the changes could affect the global climate in similarly asymmetric way with respect to other regions, this would unequivocally be the Arctic. The atmospheric branch of the hydrological cycle lies behind the linkages between the Arctic system and the global climate. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting the most significant changes in the Arctic region. This is because the transport of moisture from the extratropical regions to the Arctic has increased in recent decades, and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the assessing more objectively the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyze several recent results suggesting links between moisture transport and the extent of sea-ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnect ng results, using new information and insights. Among the many mechanisms that could be involved are hydrological (increased Arctic river discharges), radiative (increase of cloud cover and water vapour) and meteorological (increase in summer storms crossing the Arctic, or increments in precipitation).

  1. NASA High Performance Computing and Communications program

    NASA Technical Reports Server (NTRS)

    Holcomb, Lee; Smith, Paul; Hunter, Paul

    1994-01-01

    The National Aeronautics and Space Administration's HPCC program is part of a new Presidential initiative aimed at producing a 1000-fold increase in supercomputing speed and a 1(X)-fold improvement in available communications capability by 1997. As more advanced technologies are developed under the HPCC program, they will be used to solve NASA's 'Grand Challenge' problems, which include improving the design and simulation of advanced aerospace vehicles, allowing people at remote locations to communicate more effectively and share information, increasing scientists' abilities to model the Earth's climate and forecast global environmental trends, and improving the development of advanced spacecraft. NASA's HPCC program is organized into three projects which are unique to the agency's mission: the Computational Aerosciences (CAS) project, the Earth and Space Sciences (ESS) project, and the Remote Exploration and Experimentation (REE) project. An additional project, the Basic Research and Human Resources (BRHR) project, exists to promote long term research in computer science and engineering and to increase the pool of trained personnel in a variety of scientific disciplines. This document presents an overview of the objectives and organization of these projects, as well as summaries of early accomplishments and the significance, status, and plans for individual research and development programs within each project. Areas of emphasis include benchmarking, testbeds, software and simulation methods.

  2. NASA high performance computing and communications program

    NASA Technical Reports Server (NTRS)

    Holcomb, Lee; Smith, Paul; Hunter, Paul

    1993-01-01

    The National Aeronautics and Space Administration's HPCC program is part of a new Presidential initiative aimed at producing a 1000-fold increase in supercomputing speed and a 100-fold improvement in available communications capability by 1997. As more advanced technologies are developed under the HPCC program, they will be used to solve NASA's 'Grand Challenge' problems, which include improving the design and simulation of advanced aerospace vehicles, allowing people at remote locations to communicate more effectively and share information, increasing scientist's abilities to model the Earth's climate and forecast global environmental trends, and improving the development of advanced spacecraft. NASA's HPCC program is organized into three projects which are unique to the agency's mission: the Computational Aerosciences (CAS) project, the Earth and Space Sciences (ESS) project, and the Remote Exploration and Experimentation (REE) project. An additional project, the Basic Research and Human Resources (BRHR) project exists to promote long term research in computer science and engineering and to increase the pool of trained personnel in a variety of scientific disciplines. This document presents an overview of the objectives and organization of these projects as well as summaries of individual research and development programs within each project.

  3. Methods for UGV teleoperation with high latency communications

    NASA Astrophysics Data System (ADS)

    Witus, Gary; Hunt, Shawn; Janicki, Phil

    2011-05-01

    In this project, we developed and demonstrated complementary UGV control methods for teleoperation with highlatency communications. The methods included latency protection, predictive displays, and supervisory control. Latency protection mitigate against typical types of high-latency teleoperation input errors. The Phase I latency protection methods included filtering the joysick commands, limiting the commanded rates as a function of latency, and emergency stop when the operator commands and OCU navigation video were out of phase. Predictive displays indicate to the operator the current state of the UGV, i.e., the state after all of the latent commands are executed (latent commands are those that have been issued but whose effects do not yet appear in the OCU display). We implemented two alternative predictive display methods: augmented reality using iconography to indicate the effects of the latent commands, and virtual reality which warps the image to show the view to reflect the latent commands. Supervisory control allows the operator to specify simple, short-range objectives that the UGV can accomplish on its own, without advanced sensing, path planning, etc. We implemented an effective "point-and-go" supervisory control system. We successfully implemented and demonstrated these methods on a Packbot510 EOD robot (made by iRobot Corporation), currently being used in-theater.

  4. High charge short electron bunches for wakefield accelerator structures development.

    SciTech Connect

    Conde, M. E.

    1998-09-25

    The Argonne Wakefield Accelerator group develops accelerating structures based on dielectric loaded waveguides. We use high charge short electron bunches to excite wakefields in dielectric loaded structures, and a second (low charge) beam to probe the wakefields left behind by the drive beam. We report measurements of beam parameters and also initial results of the dielectric loaded accelerating structures. We have studied acceleration of the probe beam in these structures and we have also made measurements on the RF pulses that are generated by the drive beam. Single drive bunches, as well as multiple bunches separated by an integer number of RF periods have been used to generate the accelerating wakefields.

  5. Short-cavity high-repetition-rate CO2 laser

    NASA Astrophysics Data System (ADS)

    Klopper, Wouter; Bagrova, Kalina; du Pisanie, Johan; Ronander, Einar; Meyer, Jan A.; von Bergmann, Hubertus M.

    1994-09-01

    We report on the construction and optimization of a TEA CO2 laser with a discharge volume of 15 cm3 and cavity length of 20 cm. Such a short cavity facilitates single longitudinal mode operation. A roots blower is employed to achieve the necessary gas flow rate for high-repetition-frequency operation in a compact design. Output has been obtained at 1 kHz and a stable discharge to a repetition rate of 2 kHz has been demonstrated. The laser is part of a program aimed at the development of an efficient laser system for molecular laser isotope separation. Additional applications in materials processing are envisioned.

  6. Ultra short pulse generation and reshaping using highly nonlinear fibers

    NASA Astrophysics Data System (ADS)

    Matsushita, S.; Namiki, S.; Inoue, T.; Oguri, A.; Akutsu, T.; Shinozaki, J.; Ozeki, Y.; Takasaka, S.; Igarashi, K.; Sakano, M.; Yagi, T.

    2005-11-01

    We experimentally investigate the generation of a low-noise ultra short pulse train from 40GHz to160GHz by using Comb-like profiled fiber (CPF) for adiabatic soliton conversion and compression. Highly nonlinear fibers allow us to reduce total length of CPF as well as to utilize Kerr effect in the fiber effectively. We demonstrate generations of 160GHz soliton train of 750fs, the compression to 500fs of 40GHz externally-modulated pulse with wideband tunability over 30nm. Then we apply the CPF pulse compression technique to achieve the programmable repetition tunability from 5 to 500 MHz in low pedestral 300fs pulse train generation.

  7. Analysis of High Power IGBT Short Circuit Failures

    SciTech Connect

    Pappas, G.

    2005-02-11

    The Next Linear Collider (NLC) accelerator proposal at SLAC requires a highly efficient and reliable, low cost, pulsed-power modulator to drive the klystrons. A solid-state induction modulator has been developed at SLAC to power the klystrons; this modulator uses commercial high voltage and high current Insulated Gate Bipolar Transistor (IGBT) modules. Testing of these IGBT modules under pulsed conditions was very successful; however, the IGBTs failed when tests were performed into a low inductance short circuit. The internal electrical connections of a commercial IGBT module have been analyzed to extract self and mutual partial inductances for the main current paths as well as for the gate structure. The IGBT module, together with the partial inductances, has been modeled using PSpice. Predictions for electrical paths that carry the highest current correlate with the sites of failed die under short circuit tests. A similar analysis has been carried out for a SLAC proposal for an IGBT module layout. This paper discusses the mathematical model of the IGBT module geometry and presents simulation results.

  8. High spectral resolution airborne short wave infrared hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Wei, Liqing; Yuan, Liyin; Wang, Yueming; Zhuang, Xiaoqiong

    2016-05-01

    Short Wave InfraRed(SWIR) spectral imager is good at detecting difference between materials and penetrating fog and mist. High spectral resolution SWIR hyperspectral imager plays a key role in developing earth observing technology. Hyperspectral data cube can help band selections that is very important for multispectral imager design. Up to now, the spectral resolution of many SWIR hyperspectral imagers is about 10nm. A high sensitivity airborne SWIR hyperspectral imager with narrower spectral band will be presented. The system consists of TMA telescope, slit, spectrometer with planar blazed grating and high sensitivity MCT FPA. The spectral sampling interval is about 3nm. The IFOV is 0.5mrad. To eliminate the influence of the thermal background, a cold shield is designed in the dewar. The pixel number of spatial dimension is 640. Performance measurement in laboratory and image analysis for flight test will also be presented.

  9. Personal communication system combines high performance with miniaturization

    NASA Technical Reports Server (NTRS)

    Atlas, N. D.

    1967-01-01

    Personal communication system provides miniaturized components that incorporate high level signal characteristics plus noise rejection in both microphone and earphone circuitry. The microphone is designed to overcome such spacecraft flight problems as size, ambient noise level, and RF interference.

  10. Short communication: Short-term changes in stocking density did not alter meal characteristics of lactating Holstein dairy cattle.

    PubMed

    Black, R A; Grant, R J; Krawczel, P D

    2016-08-01

    The study objectives were to determine the effect of short-term increases in stocking density and milking on meal duration, meal frequency, and time between meals and to determine the bioequivalence of different meal criterions in a competitive environment. Forty-eight Holstein dairy cows were allotted to 1 of 4 groups (n=12 per group). Stocking density treatments of 100 (one cow per freestall and headlock), 113, 131, and 142% were assigned to groups using a 4×4 Latin square with treatments imposed for 14-d periods. On d 11 of each period, feeding time was recorded for 24h using 10-min scan samples from direct observation. Meals were defined as repeated observations of eating with a maximum of 20, 30, or 40min of not eating between observations constituting the same meal. A new meal was established when a cow was observed feeding and then not feeding for greater than 2 (20min), 3 (30min), or 4 (40min) observations. To evaluate diurnal effects, the 24-h period of data was divided into 8-h intervals (based on milking time); morning (0400-1200h), afternoon (1200-2000h), and night (2000-0400h). Feed delivery occurred daily at 0430h, with feed pushed up throughout the day. A mixed linear model was used to determine the effect of stocking density and time of day on meals per day, meals per hour, meal duration, time between meals, and meal duration 2h before and after milking. Regardless of stocking density, meal duration, meal frequency, meals per hour, and time between meals did not differ. Regardless of stocking density, mean meal duration was longer during the morning and afternoon compared with night. Meal duration was also greater after milking compared with before milking, regardless of stocking density. These results suggest meal length decreased throughout the day, relative to feed delivery, with periodic increases in length due to return from milking. Meals per hour, meal duration before and after milking, and meal frequency established bioequivalence for the

  11. Multimethod communication for high-performance metacomputing applications

    SciTech Connect

    Foster, I.; Geisler, J.; Tuecke, S.; Kesselman, C.

    1996-12-31

    Metacomputing systems use high-speed networks to connect supercomputers, mass storage systems, scientific instruments, and display devices with the objective of enabling parallel applications to access geographically distributed computing resources. However, experience shows that high performance often can be achieved only if applications can integrate diverse communication substrates, transport mechanisms, and protocols, chosen according to where communication is directed, what is communicated, or when communication is performed. In this article, we describe a software architecture that addresses this requirement. This architecture allows multiple communication methods to be supported transparently in a single application, with either automatic or user-specified selection criteria guiding the methods used for each communication. We describe an implementation of this architecture, based on the Nexus communication library, and use this implementation to evaluate performance issues. The implementation supported a wide variety of applications in the I-WAY metacomputing experiment at Supercomputing 95; we use one of these applications to provide a quantitative demonstration of the advantages of multimethod communication in a heterogeneous networked environment.

  12. Communication.

    ERIC Educational Resources Information Center

    Strauss, Andre

    The following essays on communication are presented: communication as a condition of survival, communication for special purposes, the means of transmission of communication, communication within social and economic structures, the teaching of communication through the press, the teaching of modern languages, communication as a point of departure,…

  13. High speed laser communication network for satellite systems

    NASA Astrophysics Data System (ADS)

    Panahi, Allen; Kazemi, Alex A.

    2011-06-01

    Using optical links in space and building high speed laser communications network has proven to be an extremely complicated task and many such schemes were tried without success in the past. However, in the last few years, there has been impressive progress made to bring the concept to fruition in civilian and government-non classified projects. In this paper we will focus on the requirements of the space-based lasers and optics used for beam forming, as well as receiver antenna gain and detectors used in free space communications. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design. Space-based optical communications using satellites in low earth orbit (LEO) and Geo-synchronous orbits (GEO) hold great promise for the proposed Internet in the Sky network of the future. Also discussed are the critical parameters in the transmitter, channel, receiver, and link budget that are employed in successful inter-satellite communications system. We cover that Laser Communications offer a viable alternative to established RF communications for inter-satellite links and other applications where high performance links are a necessity.

  14. Ultra High Bit-Rate Communications for Future Space Missions

    NASA Astrophysics Data System (ADS)

    Dudelzak, A. E.; Jha, V. K.; Pasmanik, G. A.

    2002-01-01

    systems. Needs of applications such as real-time surveillance of dynamic situations on the ground or in near space, video data on event scenes in search and rescue, real-time video communications with spacecraft, etc. can only be provided with signal carrying frequencies in the optical wavelength range. Today's optical free-space communication technologies promise to reach the performance quality of the ground optical fiber networks. Recent developments based on using the optical phase conjugation and photo- dynamic holography phenomena allow transmission of high data volumes (such as dynamic imagery and real-time video communications) between moving communication terminals. surveillance and communications with spacecraft (both within and beyond solar system) using non-linear optical systems. The advantage of the discussed concept is that it may not require lasers (as sources of the signal-carrying electromagnetic waves) on both communicating terminals. A combination of a limited number of ground-based laser stations with compact, light-weight passive non-linear optical systems on high and low orbits or on long-range spacecraft provides for reliable, ultra-high rate, economic systems for voice, data and video communications as well as real-time observations of Earth, near and deep space. presented.

  15. Advanced short haul systems in high density markets

    NASA Technical Reports Server (NTRS)

    Galloway, T. L.

    1975-01-01

    The design requirements, performance, economics, and noise aspects of STOL and VTOL conceptual aircraft developed for short haul air transportation are reviewed, along with the characteristics of areas of high-density annual passenger flow in which the aircraft are intended to operate. It is shown that aircraft of 100 to 200 passenger capacity provide the best return on investment in high density markets. The various STOL propulsive lift concepts have the same general trends with field length; their wing loadings are 20 to 30 pounds per square foot higher than the nonpropulsive lift concepts. A comparison of the aircraft under consideration shows that no one aircraft concept will be optimum for all future operational environments.

  16. NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications

    NASA Technical Reports Server (NTRS)

    Benet, James

    1993-01-01

    The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

  17. Review of high speed communications photomultiplier detectors

    NASA Technical Reports Server (NTRS)

    Enck, R. S.; Abraham, W. G.

    1978-01-01

    Four types of newly developed high speed photomultipliers are discussed: all electrostatic; static crossed field; dynamic crossed field; and hybrid (EBS). Design, construction, and performance parameters of each class are presented along with limitations of each class of device and prognosis for its future in high speed light detection. The particular advantage of these devices lies in high speed applications using low photon flux, large cathode areas, and broadband optical detection.

  18. A new short-anoded IGBT with high emission efficiency

    NASA Astrophysics Data System (ADS)

    Weizhong, Chen; Bo, Zhang; Zehong, Li; Min, Ren; Zhaoji, Li

    2012-11-01

    A novel short-anoded insulated-gate bipolar transistor (SA-IGBT) with double emitters is proposed. At the on-state, the new structure shows extraordinarily high emission efficiency. Moreover, with a short-contacted anode, it further enhances the hole emission efficiency because of the crowding of the electrons. The forward voltage drop VF of this structure is 1.74 V at a current density 100 of A/cm2. Compared to the conventional NPT IGBT (1.94 V), segment-anode IGBT (SA-NPN 2.1 V), and conventional SA-IGBT (2.33 V), VF decreased by 10%, 17% and 30%, respectively. Furthermore, no NDR has been detected comparing to the SA-IGBT. At the off-state, there is a channel for extracting excessive carriers in the drift region. The turn-off loss Eoff of this proposed structure is 8.64 mJ/cm2. Compared to the conventional NPT IGBT (15.3 mJ/cm2), SA-NPN IGBT (12.8 mJ/cm2), and SA-IGBT (12.1 mJ/cm2), Eoff decreased by 43.7%, 32% and 28%, respectively.

  19. Short communication: Proteins from circulating exosomes represent metabolic state in transition dairy cows.

    PubMed

    Crookenden, M A; Walker, C G; Peiris, H; Koh, Y; Heiser, A; Loor, J J; Moyes, K M; Murray, A; Dukkipati, V S R; Kay, J K; Meier, S; Roche, J R; Mitchell, M D

    2016-09-01

    Biomarkers that identify prepathological disease could enhance preventive management, improve animal health and productivity, and reduce costs. Circulating extracellular vesicles, particularly exosomes, are considered to be long-distance, intercellular communication systems in human medicine. Exosomes provide tissue-specific messages of functional state and can alter the cellular activity of recipient tissues through their protein and microRNA content. We hypothesized that exosomes circulating in the blood of cows during early lactation would contain proteins representative of the metabolic state of important tissues, such as liver, which play integral roles in regulating the physiology of cows postpartum. From a total of 150 cows of known metabolic phenotype, 10 cows were selected with high (n=5; high risk) and low (n=5; low risk) concentrations of nonesterified fatty acids, β-hydroxybutyrate, and liver triacylglycerol during wk 1 and 2 after calving. Exosomes were extracted from blood on the day of calving (d 0) and postcalving at wk 1 and wk 4, and their protein composition was determined by mass spectroscopy. Extracellular vesicle protein concentration and the number of exosome vesicles were not affected by risk category; however, the exosome protein cargo differed between the groups, with proteins at each time point identified as being unique to the high- and low-risk groups. The proteins α-2 macroglobulin, fibrinogen, and oncoprotein-induced transcript 3 were unique to the high-risk cows on d 0 and have been associated with metabolic syndrome and liver function in humans. Their presence may indicate a more severe inflammatory state and a greater degree of liver dysfunction in the high-risk cows than in the low-risk cows, consistent with the high-risk cows' greater plasma β-hydroxybutyrate and liver triacylglycerol concentrations. The commonly shared proteins and those unique to the low-risk category indicate a role for exosomes in immune function. The data

  20. Multipoint free-space optics system for short-range communications between flight platforms.

    PubMed

    Heng, Kiang Huat; Zhong, Wen-De; Cheng, Tee Hiang

    2010-01-10

    The problems associated with using typical free-space optics (FSO) transceivers for multipoint communications on flight platforms, such as satellites and unmanned aerial vehicles, in a cluster are discussed and the transceivers are found to be unsuitable for concurrent multipoint communications in those platforms. To overcome the problems, a multipoint FSO system design is proposed. The design of the multipoint system is described and the performance of the multipoint receiver is evaluated in terms of receive gain under different conditions. The proposed multipoint system design offers a promising way to implement concurrent multipoint communications on flight platforms with power, weight, and size advantages compared to the use of multiple transceivers. PMID:20062513

  1. Quantum data locking for high-rate private communication

    NASA Astrophysics Data System (ADS)

    Lupo, Cosmo; Lloyd, Seth

    2015-03-01

    We show that, if the accessible information is used as a security quantifier, quantum channels with a certain symmetry can convey private messages at a tremendously high rate, as high as less than one bit below the rate of non-private classical communication. This result is obtained by exploiting the quantum data locking effect. The price to pay to achieve such a high private communication rate is that accessible information security is in general not composable. However, composable security holds against an eavesdropper who is forced to measure her share of the quantum system within a finite time after she gets it.

  2. Communication: Role of short chain branching in polymer structure and dynamics

    NASA Astrophysics Data System (ADS)

    Kim, Jun Mo; Baig, Chunggi

    2016-02-01

    A comprehensive understanding of chain-branching effects, essential for establishing general knowledge of the structure-property-phenomenon relationship in polymer science, has not yet been found, due to a critical lack of knowledge on the role of short-chain branches, the effects of which have mostly been neglected in favor of the standard entropic-based concepts of long polymers. Here, we show a significant effect of short-chain branching on the structural and dynamical properties of polymeric materials, and reveal the molecular origins behind the fundamental role of short branches, via atomistic nonequilibrium molecular dynamics and mesoscopic Brownian dynamics by systematically varying the strength of the mobility of short branches. We demonstrate that the fast random Brownian kinetics inherent to short branches plays a key role in governing the overall structure and dynamics of polymers, leading to a compact molecular structure and, under external fields, to a lesser degree of structural deformation of polymer, to a reduced shear-thinning behavior, and to a smaller elastic stress, compared with their linear analogues. Their fast dynamical nature being unaffected by practical flow fields owing to their very short characteristic time scale, short branches would substantially influence (i.e., facilitate) the overall relaxation behavior of polymeric materials under various flowing conditions.

  3. Communication: Role of short chain branching in polymer structure and dynamics.

    PubMed

    Kim, Jun Mo; Baig, Chunggi

    2016-02-28

    A comprehensive understanding of chain-branching effects, essential for establishing general knowledge of the structure-property-phenomenon relationship in polymer science, has not yet been found, due to a critical lack of knowledge on the role of short-chain branches, the effects of which have mostly been neglected in favor of the standard entropic-based concepts of long polymers. Here, we show a significant effect of short-chain branching on the structural and dynamical properties of polymeric materials, and reveal the molecular origins behind the fundamental role of short branches, via atomistic nonequilibrium molecular dynamics and mesoscopic Brownian dynamics by systematically varying the strength of the mobility of short branches. We demonstrate that the fast random Brownian kinetics inherent to short branches plays a key role in governing the overall structure and dynamics of polymers, leading to a compact molecular structure and, under external fields, to a lesser degree of structural deformation of polymer, to a reduced shear-thinning behavior, and to a smaller elastic stress, compared with their linear analogues. Their fast dynamical nature being unaffected by practical flow fields owing to their very short characteristic time scale, short branches would substantially influence (i.e., facilitate) the overall relaxation behavior of polymeric materials under various flowing conditions. PMID:26931673

  4. Short communication: Feed sorting of dairy heifers is influenced by method of dietary transition.

    PubMed

    Miller-Cushon, E K; Vogel, J P; DeVries, T J

    2015-04-01

    This study investigated the effect of exposing heifers to individual feed components on the extent and pattern of feed sorting upon transition to a novel ration. Holstein heifers (394 ± 62 d old, weighing 409.8 ± 37.3 kg; mean ± SD), consuming a familiar mixed silage-based ration [55% corn silage and 45% haylage, dry matter (DM) basis], were transitioned to a novel total mixed ration [TMR; 41.6% haylage, 36.5% corn silage, 14.6% high-moisture corn, and 7.3% protein supplement, DM basis] by 1 of 2 treatments: direct transition to novel TMR (DIR; n = 5) or exposure to novel TMR components individually before receiving novel TMR (COM; n = 6). During the baseline period (d 1 to 4), all heifers were offered the familiar silage-based ration. During transition (d 5 to 12), DIR heifers received the novel TMR, whereas COM heifers received the novel TMR components offered separately, in amounts according to TMR composition (target 15% orts). After transition (d 13 to 20), all heifers received the novel TMR. Feed intake and feeding time were determined daily and fresh feed and individual orts were sampled every 2d for particle size analysis and neutral detergent fiber content. The particle size separator consisted of 3 screens (18, 9, and 1.18 mm) and a bottom pan, resulting in 4 fractions (long, medium, short, and fine). Sorting activity for each fraction was calculated as actual intake expressed as a percentage of predicted intake. We detected no effect of treatment on dry matter intake or feeding time. After transition to the novel TMR, COM heifers sorted to a greater extent than did DIR heifers, sorting against long particles (95.4 vs. 98.9%) and for short particles (101.7 vs. 100.6%). Differences in sorting patterns resulted in COM heifers tending to have lower neutral detergent fiber intake as a percentage of predicted intake (98.9 vs. 100.5%). The results of this study suggest that the degree of feed sorting may be influenced by method of transition to a novel

  5. Research with high-power short-wavelength lasers

    SciTech Connect

    Holzrichter, J.F.; Campbell, E.M.; Lindl, J.D.; Storm, E.

    1985-03-05

    Three important high-temperature, high-density experiments were conducted recently using the 10-TW, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. These experiments demonstrated successful solutions to problems that arose during previous experiments with long wavelength lasers (lambda greater than or equal to 1..mu..m) in which inertial confinement fusion (ICF), x-ray laser, and other high-temperature physics concepts were being tested. The demonstrations were: (1) large-scale plasmas (typical dimensions of up to 1000 laser wavelengths) were produced in which potentially deleterious laser-plasma instabilities were collisionally damped. (2) Deuterium-tritium fuel was imploded to a density of 20 g/cm/sup 3/ and a pressure of 10/sup 10/ atm. (3) A 700-fold amplification of soft x rays by stimulated emission at 206 and 209 A (62 eV) from Se/sup +24/ ions was observed in a laser-generated plasma. Isoelectronic scaling to 155 A (87 eV) in Y/sup +29/ was also demonstrated.

  6. High Bandwidth Communications: 2000-2004

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This custom bibliography from the NASA Scientific and Technical Information Program lists a sampling of records found in the NASA Aeronautics and Space Database. The scope of this topic includes optical and high-frequency microwave systems to enhance data transmission rates. This area of focus is one of the enabling technologies as defined by NASA s Report of the President s Commission on Implementation of United States Space Exploration Policy, published in June 2004.

  7. Patterns of communication in high-fidelity simulation.

    PubMed

    Anderson, Judy K; Nelson, Kimberly

    2015-01-01

    High-fidelity simulation is commonplace in nursing education. However, critical thinking, decision making, and psychomotor skills scenarios are emphasized. Scenarios involving communication occur in interprofessional or intraprofessional settings. The importance of effective nurse-patient communication is reflected in statements from the American Nurses Association and Quality and Safety Education for Nurses, and in the graduate outcomes of most nursing programs. This qualitative study examined the patterns of communication observed in video recordings of a medical-surgical scenario with 71 senior students in a baccalaureate program. Thematic analysis revealed patterns of (a) focusing on tasks, (b) communicating-in-action, and (c) being therapeutic. Additional categories under the patterns included missing opportunities, viewing the "small picture," relying on informing, speaking in "medical tongues," offering choices…okay?, feeling uncomfortable, and using therapeutic techniques. The findings suggest the importance of using high-fidelity simulation to develop expertise in communication. In addition, the findings reinforce the recommendation to prioritize communication aspects of scenarios and debriefing for all simulations. PMID:25545143

  8. Promoting High-Performance Computing and Communications. A CBO Study.

    ERIC Educational Resources Information Center

    Webre, Philip

    In 1991 the Federal Government initiated the multiagency High Performance Computing and Communications program (HPCC) to further the development of U.S. supercomputer technology and high-speed computer network technology. This overview by the Congressional Budget Office (CBO) concentrates on obstacles that might prevent the growth of the…

  9. The Communicative Participation Item Bank (CPIB): Item bank calibration and development of a disorder-generic short form

    PubMed Central

    Baylor, Carolyn; Yorkston, Kathryn; Eadie, Tanya; Kim, Jiseon; Chung, Hyewon; Amtmann, Dagmar

    2015-01-01

    Purpose The purpose of this study was to calibrate the items for the Communicative Participation Item Bank (CPIB) using Item Response Theory (IRT). One overriding objective was to examine if the IRT item parameters would be consistent across different diagnostic groups, thereby allowing creation of a disorder-generic instrument. The intended outcomes were the final item bank and a short form ready for clinical and research applications. Methods Self-report data were collected from 701 individuals representing four diagnoses: multiple sclerosis, Parkinson’s disease, amyotrophic lateral sclerosis and head and neck cancer. Participants completed the CPIB and additional self-report questionnaires. CPIB data were analyzed using the IRT Graded Response Model (GRM). Results The initial set of 94 candidate CPIB items were reduced to an item bank of 46 items demonstrating unidimensionality, local independence, good item fit, and good measurement precision. Differential item function (DIF) analyses detected no meaningful differences across diagnostic groups. A 10-item, disorder-generic short form was generated. Conclusions The CPIB provides speech-language pathologists with a unidimensional, self-report outcomes measurement instrument dedicated to the construct of communicative participation. This instrument may be useful to clinicians and researchers wanting to implement measures of communicative participation in their work. PMID:23816661

  10. Short-pulse high intensity laser thin foil interaction

    NASA Astrophysics Data System (ADS)

    Audebert, Patrick

    2003-10-01

    The technology of ultrashort pulse laser generation has progressed to the point that optical pulses larger than 10 J, 300 fs duration or shorter are routinely produced. Such pulses can be focused to intensities exceeding 10^18 W/cm^2. With high contrast pulses, these focused intensities can be used to heat solid matter to high temperatures with minimal hydrodynamic expansion, producing an extremely high energy-density state of matter for a short period of time. This high density, high temperature plasma can be studied by x-ray spectroscopy. We have performed experiments on thin foils of different elements under well controlled conditions at the 100 Terawatt laser at LULI to study the characteristics X-ray emission of laser heated solids. To suppress the ASE effect, the laser was frequency doubled. S-polarized light with a peak intensity of 10^19W/cm^2 was used to minimize resonance absorption. To decrease the effect of longitudinal temperature gradients very thin (800 μ) aluminum foil targets were used. We have also studied the effect of radial gradient by limiting the measured x-ray emission zone using 50μ or 100μ pinhole on target. The spectra, in the range 7-8Å, were recorded using a conical crystal spectrometer coupled to a 800 fs resolution streak camera. A Fourier Domain Interferometry (FDI) of the back of the foil was also performed providing a measurement of the hydrodynamic expansion as function of time for each shot. To simulate the experiment, we used the 1D hydrodynamic code FILM with a given set of plasma parameter (ρ, Te) as initial conditions. The X-ray emission was calculated by post processing hydrodynamic results with a collisional-radiative model which uses super-configuration average atomic data. The simulation reproduces the main features of the experimental time resolved spectrum.

  11. Photodetachment of H- from intense, short, high-frequency pulses

    NASA Astrophysics Data System (ADS)

    Shao, Hua-Chieh; Robicheaux, F.

    2016-05-01

    We study the photodetachment of an electron from the hydrogen anion due to short, high-frequency laser pulses by numerically solving the time-dependent Schrödinger equation. Simulations are performed to investigate the dependence of the photoelectron spectra on the duration, chirp, and intensity of the pulses. Specifically, we concentrate on the low-energy distributions in the spectra that result from the Raman transitions of the broadband pulses. Contrary to the one-photon ionization, the low-energy distribution maintains a similar width as the laser bandwidth is expanded by chirping the pulses. In addition, we study the transitions of the ionization dynamics from the perturbative to strong-field regime. At high intensities, the positions of the net one- and two-photon absorption peaks in the spectrum shifts and the peaks split to multiple subpeaks because of the multiphoton effects. Moreover, although the one- and two-photon peaks and low-energy distribution exhibit saturation of the ionization yields, the latter shows relatively mild saturation. This work has been supported by DOE under Award No. DE-SC0012193.

  12. Photodetachment of H- from intense, short, high-frequency pulses

    NASA Astrophysics Data System (ADS)

    Shao, Hua-Chieh; Robicheaux, F.

    2016-05-01

    We study the photodetachment of an electron from the hydrogen anion due to short, high-frequency laser pulses by numerically solving the time-dependent Schrödinger equation. Simulations are performed to investigate the dependence of the photoelectron spectra on the duration, chirp, and intensity of the pulses. Specifically, we concentrate on the low-energy distributions in the spectra that result from the Raman transitions of the broadband pulses. Contrary to one-photon ionization, the low-energy distribution maintains an almost constant width as the laser bandwidth is expanded by chirping the pulses. In addition, we study the transitions of the ionization dynamics from the perturbative to the strong-field regime. At high intensities, the positions of the net one- and two-photon absorption peaks in the spectrum shift and the peaks split to multiple subpeaks due to multiphoton effects. Moreover, although the one- and two-photon peaks and low-energy distribution exhibit saturation of the ionization yields, the low-energy distribution shows relatively mild saturation.

  13. A high current, short pulse electron source for wakefield accelerators

    SciTech Connect

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  14. A high current, short pulse electron source for wakefield accelerators

    SciTech Connect

    Ho, Ching-Hung

    1992-12-31

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  15. Performance analysis of short-range NLOS UV communication system using Monte Carlo simulation based on measured channel parameters.

    PubMed

    Luo, Pengfei; Zhang, Min; Han, Dahai; Li, Qing

    2012-10-01

    The research presented in this paper is a performance study of short-range NLOS ultraviolet (UV) communication system, using a Monte-Carlo-based system-level model, in which the channel parameters, such as the path loss and the background noise are experimentally measured using an outdoor UV communication test-bed. Various transceiver geometry and background noise condition are considered. Furthermore, 4 modulation schemes are compared, which provides an insight into the performance prediction and the system trade-offs among the path loss, the optical power, the distance, the link geometry, the bit rate and the bit error rate. Finally, advices are given on UV system design and performance improvement. PMID:23188312

  16. A Short Course in Communication for Prison Personnel & Offenders. Final Report.

    ERIC Educational Resources Information Center

    Brandes, Paul D.; Frazier, Michael

    The communication course presented in this document was developed as it was being offered at correctional centers throughout North Carolina from the fall of 1971 through the spring of 1976. The document contains 12 "encounters," or lessons, each of which discusses behavioral objectives, physical facilities, general advice, the time sequence, a…

  17. An International Short Course for Training Professionals as Effective Science Communicators

    ERIC Educational Resources Information Center

    Sarathchandra, Dilshani; Maredia, Karim M.

    2014-01-01

    Scholars have recognized a need for educational programs that prepare scientists, Extension practitioners, and other stakeholders to communicate science effectively. Such programs have the potential to increase public awareness and aid policy development. Having recognized this need, faculty at Michigan State University (MSU) developed an…

  18. The research of high efficient optical fiber coupling technology in space laser communication

    NASA Astrophysics Data System (ADS)

    Wang, Hao-zeng; Tong, Shou-feng; Zhang, Lei; Yang, Hong-kun

    2013-08-01

    With the development of optical fiber communications, especially the maturity of the optical amplifiers and the WDM technology, space optical communication at 1550 nm becomes a promising solution for future high speed satellite communication. Receiving technology with optical amplifiers and coupling space light into single mode fiber are key technologies in space optical communication at 1550 nm. Free-space-to-fiber coupling technique investigated in this paper is the first challenge of applying fiber communication techniques to free space optical communications. We analyzed the factors that affect the efficiency of free-space-to single-mode-fiber coupling based on mode-matching theory of electromagnetic fields. On this objective, in this paper, the theoretical analysis of the effect of atmospheric turbulence on the space light-single mode fiber coupling efficiency is discussed. On this basis, the short-distance experiment coupling space light into single mode fiber is carried out. 1. The main factors affecting the process coupling space light into single mode fiber are analyzed. This paper introduced the statistical theory of atmospheric turbulence and gave out the main turbulence parameters and meteyard based on the theory of the space light-single mode fiber coupling efficiency under ideal conditions. 2. The influence of atmospheric turbulence on the space light-single mode fiber coupling efficiency is analyzed and simulated. In the weak turbulence condition, mathematical model of the mean coupling efficiency and its fluctuation variance was given. And the fluctuation variance of coupling efficiency was simulated studied under the atmospheric conditions. The influences on the average coupling efficiency was theoretically studied, which were induced by the structure constant of atmospheric refractive index, the diameter of coupling lens and the single-mode fiber mode field radius. 3. Validating the theoretical model by a experiment under a short link coupling

  19. SLIM, Short-pulse Technology for High Gradient Induction Accelerators

    SciTech Connect

    Arntz, Floyd; Kardo-Sysoev, A.; Krasnykh, A.; /SLAC

    2008-12-16

    A novel short-pulse concept (SLIM) suited to a new generation of a high gradient induction particle accelerators is described herein. It applies advanced solid state semiconductor technology and modern microfabrication techniques to a coreless induction method of charged particle acceleration first proven on a macro scale in the 1960's. Because this approach avoids use of magnetic materials there is the prospect of such an accelerator working efficiently with accelerating pulses in the nanosecond range and, potentially, at megahertz pulse rates. The principal accelerator section is envisioned as a stack of coreless induction cells, the only active element within each being a single, extremely fast (subnanosecond) solid state opening switch: a Drift Step Recovery Diode (DSRD). Each coreless induction cell incorporates an electromagnetic pulse compressor in which inductive energy developed within a transmission-line feed structure over a period of tens of nanoseconds is diverted to the acceleration of the passing charge packet for a few nanoseconds by the abrupt opening of the DSRD switch. The duration of this accelerating output pulse--typically two-to-four nanoseconds--is precisely determined by a microfabricated pulse forming line connected to the cell. Because the accelerating pulse is only nanoseconds in duration, longitudinal accelerating gradients approaching 100 MeV per meter are believed to be achievable without inciting breakdown. Further benefits of this approach are that, (1) only a low voltage power supply is required to produce the high accelerating gradient, and, (2) since the DSRD switch is normally closed, voltage stress is limited to a few nanoseconds per period, hence the susceptibility to hostile environment conditions such as ionizing radiation, mismatch (e.g. in medical applications the peak beam current may be low), strong electromagnetic noise levels, etc is expected to be minimal. Finally, we observe the SLIM concept is not limited to linac

  20. High Performance Computing and Communications: Toward a National Information Infrastructure.

    ERIC Educational Resources Information Center

    Federal Coordinating Council for Science, Engineering and Technology, Washington, DC.

    This report describes the High Performance Computing and Communications (HPCC) initiative of the Federal Coordinating Council for Science, Engineering, and Technology. This program is supportive of and coordinated with the National Information Infrastructure Initiative. Now halfway through its 5-year effort, the HPCC program counts among its…

  1. High School Agricultural Communications Competencies: A National Delphi Study.

    ERIC Educational Resources Information Center

    Akers, Cindy L.; Vaughn, Paul R.; Haygood, Jacqui D.

    2003-01-01

    In a three-round Delphi study, agriscience faculty (n=75, 43, 41) refined and categorized competencies in 11 topic areas for a high school agricultural communications course. Appropriate topics and competencies for beginning and intermediate levels were identified. (Contains 12 references.) (SK)

  2. Non-chemical and non-contact cell-to-cell communication: a short review

    PubMed Central

    Scholkmann, Felix; Fels, Daniel; Cifra, Michal

    2013-01-01

    Cell-to-cell communication is the basis of coordinated cellular activity and thus fundamental for the functioning of biological systems. In a recently published research article by Chaban et al. (Am. J. Transl. Res., 5(1), 69-79), the authors report on interesting new experimental findings supporting a neuro-hormonal independent, non-diffusible cell-to-cell signaling. Our paper aims to (i) discuss some critical notions used by the authors to describe their findings, and (ii) briefly review related experimental work performed so far but not discussed in the original work of Chaban et al. In our opinion, the research on principles of non-chemical and non-contact cell-to-cell communication has the potential to offer new fundamental insights into biological processes. With this paper, we want to encourage future research on this topic by discussing critical issues and giving an overview of the current state of research. PMID:24093056

  3. Non-chemical and non-contact cell-to-cell communication: a short review.

    PubMed

    Scholkmann, Felix; Fels, Daniel; Cifra, Michal

    2013-01-01

    Cell-to-cell communication is the basis of coordinated cellular activity and thus fundamental for the functioning of biological systems. In a recently published research article by Chaban et al. (Am. J. Transl. Res., 5(1), 69-79), the authors report on interesting new experimental findings supporting a neuro-hormonal independent, non-diffusible cell-to-cell signaling. Our paper aims to (i) discuss some critical notions used by the authors to describe their findings, and (ii) briefly review related experimental work performed so far but not discussed in the original work of Chaban et al. In our opinion, the research on principles of non-chemical and non-contact cell-to-cell communication has the potential to offer new fundamental insights into biological processes. With this paper, we want to encourage future research on this topic by discussing critical issues and giving an overview of the current state of research. PMID:24093056

  4. A secure communications infrastructure for high-performance distributed computing

    SciTech Connect

    Foster, I.; Koenig, G.; Tuecke, S.

    1997-08-01

    Applications that use high-speed networks to connect geographically distributed supercomputers, databases, and scientific instruments may operate over open networks and access valuable resources. Hence, they can require mechanisms for ensuring integrity and confidentially of communications and for authenticating both users and resources. Security solutions developed for traditional client-server applications do not provide direct support for the program structures, programming tools, and performance requirements encountered in these applications. The authors address these requirements via a security-enhanced version of the Nexus communication library; which they use to provide secure versions of parallel libraries and languages, including the Message Passing Interface. These tools permit a fine degree of control over what, where, and when security mechanisms are applied. In particular, a single application can mix secure and nonsecure communication, allowing the programmer to make fine-grained security/performance tradeoffs. The authors present performance results that quantify the performance of their infrastructure.

  5. Ka-band MMIC microstrip array for high rate communications

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Raquet, C. A.; Tolleson, J. B.; Sanzgiri, S. M.

    1991-01-01

    In a recent technology assessment of alternative communication systems for the space exploration initiative (SEI), Ka-band (18 to 40 GHz) communication technology was identified to meet the mission requirements of telecommunication, navigation, and information management. Compared to the lower frequency bands, Ka-band antennas offer higher gain and broader bandwidths; thus, they are more suitable for high data rate communications. Over the years, NASA has played an important role in monolithic microwave integrated circuit (MMIC) phased array technology development, and currently, has an ongoing contract with Texas Instrument (TI) to develop a modular Ka-band MMIC microstrip subarray (NAS3-25718). The TI contract emphasizes MMIC integration technology development and stipulates using existing MMIC devices to minimize the array development cost. The objective of this paper is to present array component technologies and integration techniques used to construct the subarray modules.

  6. System and method that suppresses intensity fluctuations for free space high-speed optical communication

    DOEpatents

    Berman, Gennady P.; Bishop, Alan R.; Nguyen, Dinh C.; Chernobrod, Boris M.; Gorshkov, Vacheslav N.

    2009-10-13

    A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

  7. Plasmas and Short-Pulse, High-Intensity Lasers

    NASA Astrophysics Data System (ADS)

    Clark, Thomas

    1999-11-01

    Many of the applications of short-pulse, high-intensity laser systems, including coherent UV and X-ray generation, compact particle accelerators, and non-perturbative nonlinear optics as well as the study of laser-matter interaction physics, require large intensity-interaction length products. In recent years, plasma structures resulting from the hydrodynamic evolution of laser-produced plasma filaments have proven to be attractive media for guiding pulses with peak powers approaching the terawatt level over lengths many times the vacuum Rayleigh range. The hydrodynamics of plasma waveguides have been characterized using time- and space-resolved interferometry measurements of electron density profiles. The laser-driven ionization and heating phase of the plasma filament creation is followed by hot electron driven plasma expansion. Density profiles suitable for optical guiding develop within the first few hundred picoseconds after plasma creation, during which rapid cooling occurs. At longer times the plasma expansion closely follows that of a cylindrical blast wave, with further cooling due to expansion work. The observed guided intensity profiles of end-coupled and tunnel-coupled pulses compare favorably with calculations of the quasi-bound waveguide modes based on the measured electron density profiles. Time- and space-resolved electron density measurements of a laser-driven concentric implosion were also performed. The implosion is the result of the interaction of a second laser pulse with an existing plasma waveguide. The two-pulse absorption and ionization significantly exceed that due to a single pulse of the same total energy. The author would like to acknowledge the significant contributions of Prof. Howard M. Milchberg to the work being presented.

  8. Iridium Short Burst Data: Two-Way, Robust, Reliable, Low Power Communications for Oceanographic Data Transmission Applications

    NASA Astrophysics Data System (ADS)

    Roggenstein, E. B.; Hensley, W.

    2011-12-01

    Over the past two hundred years, water level observations in coastal areas have been used to help mariners navigate oceans and estuaries, cartographers develop nautical charts, government agencies regulate boundaries, and scientists gain a better understanding of various physical processes in the ocean. As technology has progressed the latency in providing these data to the user has been reduced. The National Oceanic and Atmospheric Administration's (NOAA) Center for Operational Oceanographic Products and Services (CO-OPS) provides near real-time oceanographic and meteorological data to support navigation, coastal managers, and storm surge and tsunami warning programs. CO-OPS maintains the National Water Level Observation Network (NWLON), a system of over 200 stations for the coastal United States, Great Lakes, Caribbean islands, and Pacific island territories. CO-OPS also supports the NOAA Physical Oceanographic Real Time Systems° (PORTS), which are currently operating in 21 US ports. With an expanding role in Arctic and Alaska support, CO-OPS has identified a need for a robust and reliable data communications pathway to supplement the existing Geostationary Operational Environmental Systems (GOES) network, which has limitations at high latitudes. Iridium satellite Short Burst Data (SBD) services offer a global coverage, including remote Arctic regions outside of GOES coverage. Previous testing conducted by CO-OPS has shown a great potential for the SBD service including continuous near-real-time 6 minute data transmissions from two CO-OPS test water level stations located in Guam, with >99.9% data return. Also, successful transmissions of hourly wave statistics were demonstrated with a with a test system that employed a Nortek Acoustic Wave and Current (AWAC) instrument in Chesapeake Bay were accomplished. Data transmissions involved a buoy-mounted SIM-less SBD modem. Independent of location, data can be transmitted from a remote instrument platform to Iridium

  9. Photonics and other approaches to high speed communications

    NASA Technical Reports Server (NTRS)

    Maly, Kurt

    1992-01-01

    Our research group of 4 faculty and about 10-15 graduate students was actively involved (as a group) in the development of computer communication networks for the last five years. Many of its individuals have been involved in related research for a much longer period. The overall research goal is to extend network performance to higher data rates, to improve protocol performance at most ISO layers and to improve network operational performance. We briefly state our research goals, then discuss the research accomplishments and direct your attention to attached and/or published papers which cover the following topics: scalable parallel communications; high performance interconnection between high data rate networks; and a simple, effective media access protocol system for integrated, high data rate networks.

  10. Short Communication: Dynamic Constraints on the Second Phase Compartment of HIV-Infected Cells

    PubMed Central

    Spivak, Adam M.; Rabi, S. Alireza; McMahon, Moira A.; Shan, Liang; Sedaghat, Ahmad R.; Wilke, Claus O.

    2011-01-01

    Abstract The cells responsible for the second phase decay of HIV-1 viremia following the initiation of antiretroviral therapy have yet to be identified. A dynamic model that considers where drugs act in the virus life cycle places constraints on candidate cell types. In this regard, the rapid drop in viremia in patients starting regimens containing the integrase inhibitor raltegravir is of particular interest. We show here that the time delay between reverse transcription and integration is short in differentiated macrophages, making these cells poor candidates for the second phase compartment under the assumptions of standard models of viral dynamics. PMID:21105850

  11. Solid state laser communications in space (SOLACOS) high data rate satellite communication system verification program

    NASA Astrophysics Data System (ADS)

    Pribil, Klaus; Flemmig, Joerg

    1994-09-01

    This paper gives an overview on the current development status of the SOLACOS program and presents the highlights of the program. SOLACOS (Solid State Laser Communications in Space) is the national German program to develop a high performance laser communication system for high data rate transmission between LEO and GEO satellites (Inter Orbit Link, IOL). Two experimental demonstrator terminals are designed and developed in the SOLACOS program. The main development objectives are the Pointing Acquisition and Tracking subsystem (PAT) and the high data rate communication system. All key subsystems and components are straightway developed to be upgraded in follow- on projects to full space qualification. The main design objective for the system is a high degree of modularity which allows to easily upgrade the system with new upcoming technologies. Therefore, all main subsystems are interconnected via fibers to ease replacement of subsystems. The system implements an asymmetric data link with a 650 MBit/s return channel and a 10 MBit/s forward channel. The 650 MBit/s channel is based on a diode pumped Nd:YAG, Integrated Optics Modulator and uses the syncbit transmission scheme. In the syncbit system synchronization information which is necessary to maintain phase lock of the local oscillator of the coherent receiver is transmitted time multiplexed into the data stream. The PAT system comprises two beam detection sensors and three beam steering elements. For initial acquisition and tracking of the remote satellite a high speed CCD camera with an integrated image processing unit, the Acquisition and Tracking Sensor (ATS) is used. In the tacking mode the beam position is sensed via the Fibernutator sensor which is also used to couple the incoming signal into the receiver fiber. Incoming and outgoing beams are routed through the telescopes which are positioned with a 2 axis gimbal mechanism and a high speed beam steering mirror. The PAT system is controlled by a digital

  12. Analysis of SCTP and TCP based communication in high-speed clusters

    NASA Astrophysics Data System (ADS)

    Kozlovszky, M.; Berceli, T.; Kutor, L.

    2006-04-01

    Performance and financial constraints are pushing modern DAQs (Data Acquisition Systems) to use distributed cluster environments instead of monolith one-box systems. Inside clusters application communication layers should support outstanding high performance requirements. We are currently investigating different network protocols that could meet the requirements of high speed/low latency peer-to-peer communication within DAQ clusters. We have carried out various performance measurements with TCP and SCTP over Fast and Gigabit Ethernet. We are focusing on Ethernet Technologies, because this transport medium is broad deployed, cost efficient and it has much better cost/throughput ratio than other available communication alternatives (e.g.: Myrinet, Infiniband). During this study, a protocol performance measurement application with different peer transport components has been developed. In the first part of the paper, we give a short comparison of the two protocols (SCTP and TCP), and an introduction of the transport layer structure developed. Later on we discuss the performance results of single/multi-stream peer-to-peer communication, give overview about application code transition possibilities from application developer point of view between the two protocols, and draw conclusions about usability.

  13. Stagings: Short Scripts for Middle and High School Students.

    ERIC Educational Resources Information Center

    Garner, Joan

    Introducing students to the magic of theater and helping them develop dramatic skills, this book presents nine reproducible scripts for short plays (15 to 25 minutes) with characters and story lines that will appeal to young people. The scripts in the book encompass a variety of story types, from adaptations of well-known fairy tales to original…

  14. High Data Rate Satellite Communications for Environmental Remote Sensing

    NASA Astrophysics Data System (ADS)

    Jackson, J. M.; Munger, J.; Emch, P. G.; Sen, B.; Gu, D.

    2014-12-01

    Satellite to ground communication bandwidth limitations place constraints on current earth remote sensing instruments which limit the spatial and spectral resolution of data transmitted to the ground for processing. Instruments such as VIIRS, CrIS and OMPS on the Soumi-NPP spacecraft must aggregate data both spatially and spectrally in order to fit inside current data rate constraints limiting the optimal use of the as-built sensors. Future planned missions such as HyspIRI, SLI, PACE, and NISAR will have to trade spatial and spectral resolution if increased communication band width is not made available. A number of high-impact, environmental remote sensing disciplines such as hurricane observation, mega-city air quality, wild fire detection and monitoring, and monitoring of coastal oceans would benefit dramatically from enabling the downlinking of sensor data at higher spatial and spectral resolutions. The enabling technologies of multi-Gbps Ka-Band communication, flexible high speed on-board processing, and multi-Terabit SSRs are currently available with high technological maturity enabling high data volume mission requirements to be met with minimal mission constraints while utilizing a limited set of ground sites from NASA's Near Earth Network (NEN) or TDRSS. These enabling technologies will be described in detail with emphasis on benefits to future remote sensing missions currently under consideration by government agencies.

  15. Preliminary investigation of acoustic bar codes for short-range underwater communications

    NASA Astrophysics Data System (ADS)

    Jones, Dennis F.

    2005-09-01

    In March 2005, underwater acoustic communications experiments were carried out from the DRDC Atlantic research vessel CFAV QUEST. A battery-operated BATS20 transmitter and a broadband barrel-stave flextensional transducer were used to broadcast noise containing acoustic bar code (ABC) information. The ABCs are silent frequency bands of fixed duration that resemble retail bar codes when viewed in a spectrogram. Two sites were selected for the experiments. The first was a shallow-water area west of the Berry Islands in the Bahamas, and the second was a deep-water site south of the Western Bank on the Scotian Shelf. Two receiver systems were deployed; autonomous, variable-buoyancy Stealth Buoys resting on the bottom at the shallow site, and drifting AN/SSQ-53F sonobuoys fitted with GPS at the deep site. Results from these experiments will be presented and future work will be discussed.

  16. High Temperature Wireless Communication And Electronics For Harsh Environment Applications

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; Neudeck, P. G.; Beheim, G. M.; Ponchak, G. E.; Chen, L.-Y

    2007-01-01

    In order for future aerospace propulsion systems to meet the increasing requirements for decreased maintenance, improved capability, and increased safety, the inclusion of intelligence into the propulsion system design and operation becomes necessary. These propulsion systems will have to incorporate technology that will monitor propulsion component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This implies the development of sensors, actuators, and electronics, with associated packaging, that will be able to operate under the harsh environments present in an engine. However, given the harsh environments inherent in propulsion systems, the development of engine-compatible electronics and sensors is not straightforward. The ability of a sensor system to operate in a given environment often depends as much on the technologies supporting the sensor element as the element itself. If the supporting technology cannot handle the application, then no matter how good the sensor is itself, the sensor system will fail. An example is high temperature environments where supporting technologies are often not capable of operation in engine conditions. Further, for every sensor going into an engine environment, i.e., for every new piece of hardware that improves the in-situ intelligence of the components, communication wires almost always must follow. The communication wires may be within or between parts, or from the engine to the controller. As more hardware is added, more wires, weight, complexity, and potential for unreliability is also introduced. Thus, wireless communication combined with in-situ processing of data would significantly improve the ability to include sensors into high temperature systems and thus lead toward more intelligent engine systems. NASA Glenn Research Center (GRC) is presently leading the development of electronics, communication systems, and sensors capable of prolonged stable

  17. High performance computing and communications: FY 1996 implementation plan

    SciTech Connect

    1995-05-16

    The High Performance Computing and Communications (HPCC) Program was formally authorized by passage of the High Performance Computing Act of 1991, signed on December 9, 1991. Twelve federal agencies, in collaboration with scientists and managers from US industry, universities, and research laboratories, have developed the Program to meet the challenges of advancing computing and associated communications technologies and practices. This plan provides a detailed description of the agencies` HPCC implementation plans for FY 1995 and FY 1996. This Implementation Plan contains three additional sections. Section 3 provides an overview of the HPCC Program definition and organization. Section 4 contains a breakdown of the five major components of the HPCC Program, with an emphasis on the overall directions and milestones planned for each one. Section 5 provides a detailed look at HPCC Program activities within each agency.

  18. Communications

    NASA Technical Reports Server (NTRS)

    Stouffer, Donald D.

    1990-01-01

    Communication in its many forms is a critical component for an effective Space Grant Program. Good communication is needed within individual Space Grant College/Consortia, for example between consortium affiliates and the consortium program office. Effective communication between the several programs, NASA Headquarters, and NASA field centers also is required. Further, communication among the above program elements, industry, local and state government, and the public also are necessary for meeting program objectives.

  19. Low Cost Cryocoolers for High Temperature Superconductor Communication Filters

    NASA Technical Reports Server (NTRS)

    Brown, Davina

    1998-01-01

    This final report describes the work performed by a consortium of Industry and Government to develop low cost cryocoolers. The specific application was for low cost commercial based high temperature superconductor communication filters. This program was initiated in January 1995 and resulted in the successful demonstration of an HTS filter dewar cooled by a low cost pulse tube cryocooler. Further development of this cryocooler technology is proceeding through various contracts underway and proposed at this time.

  20. Short communication: Effect of diet changes on sorting behavior of weaned dairy calves.

    PubMed

    Costa, J H C; Adderley, N A; Weary, D M; von Keyserlingk, M A G

    2016-07-01

    Dairy cows sort mixed rations; in some cases sorting can lead to digestive disorders. How sorting behavior develops in calves is poorly understood. The objective of this observational study was to determine if sorting behavior of total mixed ration (TMR)-fed dairy calves was affected by the removal of supplementary concentrate. Dairy bull calves (n=18) were provided access to both a TMR (49.1% dry matter) and calf starter fed separately during the preweaning period starting at 3 d of age. Sorting of the TMR was assessed after weaning when calves were provided both feeds at 65 d of age, and again at 70 d immediately following the removal of calf starter from the calf pen. Sorting was measured by comparing the particle size composition of the TMR offered with that of the orts following 24h of feed access. Feed particle fractions were measured using the Penn State Particle Separator with 3 screens (19, 8, and 1.18mm) and a bottom pan to separate the TMR into long, medium, short, and fine fractions, respectively. At d 65, calves sorted for long particles (133±9%) and against small particles (92±3%), with no differences for the remaining fractions (99±5% for medium; 107±5% for fine); these preferences were reversed at d 70 when calf starter was no longer available with calves preferentially selecting fine particles (113±4%), but showing no preference for other fractions (101±11% for long; 99±6% for medium; 97±4% for short). These results indicate that young dairy calves are capable of sorting a TMR and they adjust this behavior in response to the availability of grain. PMID:27108168

  1. Taipei's Use of a Multi-Channel Mass Risk Communication Program to Rapidly Reverse an Epidemic of Highly Communicable Disease

    PubMed Central

    Yen, Muh-Yong; Wu, Tsung-Shu Joseph; Chiu, Allen Wen-Hsiang; Wong, Wing-Wai; Wang, Po-En; Chan, Ta-Chien; King, Chwan-Chuen

    2009-01-01

    Background In September 2007, an outbreak of acute hemorrhagic conjunctivitis (AHC) occurred in Keelung City and spread to Taipei City. In response to the epidemic, a new crisis management program was implemented and tested in Taipei. Methodology and Principal Findings Having noticed that transmission surged on weekends during the Keelung epidemic, Taipei City launched a multi-channel mass risk communications program that included short message service (SMS) messages sent directly to approximately 2.2 million Taipei residents on Friday, October 12th, 2007. The public was told to keep symptomatic students from schools and was provided guidelines for preventing the spread of the disease at home. Epidemiological characteristics of Taipei's outbreak were analyzed from 461 sampled AHC cases. Median time from exposure to onset of the disease was 1 day. This was significantly shorter for cases occurring in family clusters than in class clusters (mean±SD: 2.6±3.2 vs. 4.39±4.82 days, p = 0.03), as well as for cases occurring in larger family clusters as opposed to smaller ones (1.2±1.7 days vs. 3.9±4.0 days, p<0.01). Taipei's program had a significant impact on patient compliance. Home confinement of symptomatic children increased from 10% to 60% (p<0.05) and helped curb the spread of AHC. Taipei experienced a rapid decrease in AHC cases between the Friday of the SMS announcement and the following Monday, October 15, (0.70% vs. 0.36%). By October 26, AHC cases reduced to 0.01%. The success of this risk communication program in Taipei (as compared to Keelung) is further reflected through rapid improvements in three epidemic indicators: (1) significantly lower crude attack rates (1.95% vs. 14.92%, p<0.001), (2) a short epidemic period of AHC (13 vs. 34 days), and (3) a quick drop in risk level (1∼2 weeks) in Taipei districts that border Keelung (the original domestic epicenter). Conclusions and Significance The timely launch of this systematic, communication

  2. Earth Science Mission Benefits of High Data Rate Satellite Communications

    NASA Astrophysics Data System (ADS)

    Jackson, J. M.; Munger, J.; Emch, P. G.; Sen, B.; Gu, D.

    2013-12-01

    Satellite to ground communication bandwidth limitations place constraints on current earth remote sensing instruments which limit the spatial and spectral resolution of data transmitted to the ground for processing. Instruments such as VIIRS, CrIS and OMPS on the Soumi-NPP spacecraft must aggregate data both spatially and spectrally in order to fit inside current data rate constraints limiting the optimal use of the as-built sensors. Future planned missions such as PACE, TEMPO and DESDynI Radar will have to trade spatial and spectral resolution if increased communication band width is not made available. A number of high-impact, environmental remote sensing disciplines such as hurricane observation, mega-city air quality, wild fire detection and monitoring, and monitoring of coastal oceans would benefit dramatically from enabling the downlinking of sensor data at higher spatial and spectral resolutions. The enabling technologies of multi-Gbps Ka-Band communication and multi-Terabit SSRs are currently available with high technological maturity enabling high data volume mission requirements to be met with minimal mission constraints while utilizing only a very few ground sites from NASA's Near Earth Network (NEN). These enabling technologies will be described in detail with emphasis on benefits to future remote sensing missions currently under consideration by government agencies.

  3. Highly survivable communications: Complementary media packet switched networks

    NASA Astrophysics Data System (ADS)

    Yavuz, D.; Eken, F.; Karavassilis, N.

    1994-07-01

    The requirement for highly survivable communications (HSC) for essential command functions in military operations does not need any justification. The ability to communicate under extreme jamming levels and adverse propagation conditions, including high altitude nuclear events, is a very important requirement. There are also many natural disaster related requirements that also need such highly survivable communications. The prevalent and in a sense classical, approach to provide highly assured connectivity can be summarized as follows: Take a particular propagation medium and try to obtain the ultimate performance from it. There are many examples of this philosophy some successful, most not. Our approach, on the other hand, is to use complementary multi-media or mixed-media where communication links utilizing essentially commercial-off-the-shelf (COTS) equipment are integrated using packet radio (PR) techniques. There is also, in our view, an even more fundamental, recently discovered consideration why the expectation of continuous incremental refinement of a system using a given single media may be be achievable. This is derived from the theory of 'deterministic uncertainty' or more popularly known as 'theory of CHAOS', systems whose state space behavior has fractal characteristics. We will elaborate on this novel argument. Complementary multi-media approach has been the focus for all HSC communications activities at STC since 1982. The original STC studies and prototypes were in response to requirements of broadcasting (i.e., one-way transmission) information. A high frequency (HF)/meteorburst (MB) system was developed/prototyped/tested demonstrating the cost effectiveness of the approach. These results are reviewed. More recently, in 1992 STC has completed the development/test of an Open Systems Interconnection (OSI) HF packet radio protocol as no such open or non-proprietary protocol exists. This protocol has been fully tested, documented and made available to

  4. Short-term Music Training Enhances Complex, Distributed Neural Communication during Music and Linguistic Tasks.

    PubMed

    Carpentier, Sarah M; Moreno, Sylvain; McIntosh, Anthony R

    2016-10-01

    Musical training is frequently associated with benefits to linguistic abilities, and recent focus has been placed on possible benefits of bilingualism to lifelong executive functions; however, the neural mechanisms for such effects are unclear. The aim of this study was to gain better understanding of the whole-brain functional effects of music and second-language training that could support such previously observed cognitive transfer effects. We conducted a 28-day longitudinal study of monolingual English-speaking 4- to 6-year-old children randomly selected to receive daily music or French language training, excluding weekends. Children completed passive EEG music note and French vowel auditory oddball detection tasks before and after training. Brain signal complexity was measured on source waveforms at multiple temporal scales as an index of neural information processing and network communication load. Comparing pretraining with posttraining, musical training was associated with increased EEG complexity at coarse temporal scales during the music and French vowel tasks in widely distributed cortical regions. Conversely, very minimal decreases in complexity at fine scales and trends toward coarse-scale increases were displayed after French training during the tasks. Spectral analysis failed to distinguish between training types and found overall theta (3.5-7.5 Hz) power increases after all training forms, with spatially fewer decreases in power at higher frequencies (>10 Hz). These findings demonstrate that musical training increased diversity of brain network states to support domain-specific music skill acquisition and music-to-language transfer effects. PMID:27243611

  5. Development of short message service application for patient-provider communication in clinical psychiatry.

    PubMed

    Mäkelä, Kari; Paavola, Teemu; Stenman, Markku

    2010-09-01

    This prospective study is the first one of its kind carried out in Finland, in which a simple technological platform was developed to merge traditional text messaging with an electronic patient information database. The technology has been tested for relaying two-way treatment messages in psychiatry provided by a central hospital offering secondary healthcare. Text messaging was found to be particularly well suited for young people who have to travel to the outpatient clinic over long distances or who face the risk of social exclusion. According to clinicians, the text message reminders sent between the visits, which take place every 1-2 months, can encourage the young people in question to stay in touch more frequently, which will help to improve their relationship with the hospital staff. The project is still in the pilot stage, and so far the most important results concern the development of the operating culture and, surprisingly enough, legal aspects. From the legal point of view, the hospital had to equate text messages with phone communications. For this reason, it was not possible to put the text messages into a separate register and they have not been archived either. The success or failure of the new innovative healthcare solution may, therefore, depend on both technological aspects and legal factors. PMID:20815750

  6. SHORT COMMUNICATION: Comments on recent proposals for redefining the mole and kilogram

    NASA Astrophysics Data System (ADS)

    Leonard, B. P.

    2010-06-01

    The fundamental concept of the mole requires the number of entities comprising one mole, i.e. Avogadro's number, to be exactly equal to the gram-to-dalton mass ratio. If this compatibility condition is to be satisfied, the mole, the kilogram and the dalton cannot all be defined independently. This note concerns recent Metrologia publications that do, however, propose independent definitions of all three quantities: the mole by fixing the value of Avogadro's number and the kilogram by fixing the value of the Planck constant, while retaining the current carbon-12-based dalton. Adoption of these incompatible definitions would likely cause serious widespread confusion and might even result in a split in scholarly and technical communication between the quantum physics and chemistry communities. Other entirely compatible alternatives are possible: either retaining the current (inexact) carbon-12-based mole and dalton with an independently redefined kilogram or redefining the mole by fixing the value of Avogadro's number, with a compatible dalton that is exact in terms of the redefined kilogram.

  7. All-reflective, highly accurate polarization rotator for high-power short-pulse laser systems.

    PubMed

    Keppler, S; Hornung, M; Bödefeld, R; Kahle, M; Hein, J; Kaluza, M C

    2012-08-27

    We present the setup of a polarization rotating device and its adaption for high-power short-pulse laser systems. Compared to conventional halfwave plates, the all-reflective principle using three zero-phase shift mirrors provides a higher accuracy and a higher damage threshold. Since plan-parallel plates, e.g. these halfwave plates, generate postpulses, which could lead to the generation of prepulses during the subsequent laser chain, the presented device avoids parasitic pulses and is therefore the preferable alternative for high-contrast applications. Moreover the device is easily scalable for large beam diameters and its spectral reflectivity can be adjusted by an appropriate mirror coating to be well suited for ultra-short laser pulses. PMID:23037123

  8. A UHF RFID system with on-chip-antenna tag for short range communication

    NASA Astrophysics Data System (ADS)

    Qi, Peng; Chun, Zhang; Xijin, Zhao; Zhihua, Wang

    2015-05-01

    A UHF RF identification system based on the 0.18 μm CMOS process has been developed for short range and harsh size requirement applications, which is composed of a fully integrated tag and a special reader. The whole tag chip with the antenna takes up an area of 0.36 mm2, which is smaller than other reported tags with an on-chip antenna (OCA) using the standard CMOS process. A self-defined protocol is proposed to reduce the power consumption, and minimize the size of the tag. The specialized SOC reader system consists of the RF transceiver, digital baseband, MCU and host interface. Its power consumption is about 500 mW. Measurement results show that the system's reading range is 2 mm with 20 dBm reader output power. With an inductive antenna printed on a paper substrate around the OCA tag, the reading range can be extended from several centimeters to meters, depending on the shape and size of the inductive antenna.

  9. When are high-tech communicators effective in Parkinson's disease?

    PubMed

    Ferriero, Giorgio; Caligari, Marco; Ronconi, Gianpaolo; Franchignoni, Franco

    2012-03-01

    This report describes a 63-year-old woman with Parkinson's disease showing loss of intelligibility of speech and severely impaired handwriting, despite undergoing physical and speech therapies. As the patient had sufficient residual motor abilities and adequate cognitive function and motivation, a computer-based communication aid with a software program for word prediction and voice output was tested, and was prescribed after a training period. One year later, the patient was still using the customized device to communicate and for leisure time, showing a high degree of satisfaction with the aid (assessed by QUEST 2.0), which had a positive impact on her well-being and quality of life (assessed by Psychosocial Impact of Assistive Devices Scales). In conclusion, in selected patients with Parkinson's disease, high-tech augmentative and alternative communication devices may be considered, tested, and prescribed after a positive training period. Follow-ups are necessary to monitor the effectiveness of the assistive device and respond to specific patient needs that may arise with using the device. PMID:22186614

  10. High-power diode lasers for optical communications applications

    NASA Technical Reports Server (NTRS)

    Carlin, D. B.; Goldstein, B.; Channin, D. J.

    1985-01-01

    High-power, single-mode, double-heterojunction AlGaAs diode lasers are being developed to meet source requirements for both fiber optic local area network and free space communications systems. An individual device, based on the channeled-substrate-planar (CSP) structure, has yielded single spatial and longitudinal mode outputs of up to 90 mW CW, and has maintained a single spatial mode to 150 mW CW. Phase-locked arrays of closely spaced index-guided lasers have been designed and fabricated with the aim of multiplying the outputs of the individual devices to even higher power levels in a stable, single-lobe, anastigmatic beam. The optical modes of the lasers in such arrays can couple together in such a way that they appear to be emanating from a single source, and can therefore be efficiently coupled into optical communications systems. This paper will review the state of high-power laser technology and discuss the communication system implications of these devices.

  11. Measurement of endogenous allergens in genetically modified soybeans--short communication.

    PubMed

    Ladics, Gregory S; Budziszewski, Gregory J; Herman, Rod A; Herouet-Guicheney, Corinne; Joshi, Saurabh; Lipscomb, Elizabeth A; McClain, Scott; Ward, Jason M

    2014-10-01

    The measurement of endogenous allergens is required by the European Commission (EC) as part of the compositional analysis for GM products from host plants that are common causes of food allergy, such as soybean (EC Implementing Regulation No. 503/2013). In each case, the EC Implementing Regulation indicates that analysis be conducted on identified allergens as specified in the Organization of Economic Cooperation and Development (OECD) consensus documents on compositional considerations for new plant varieties. This communication discusses the methods available to measure endogenous allergens as well as the endogenous soybean allergens that should be analyzed. It is suggested herein that in conjunction with the 2012 OECD consensus document on soybean, any list of soybean allergens should be based on clinically relevant data among publicly available allergen databases and peer-reviewed scientific publications, and the ability to measure the identified allergen. Based on a detailed analysis of the scientific literature, the following key points are recommended: (1) the acceptance of serum-free, quantitative analytical method data as an alternative to traditional IgE reactivity qualitative or semi-quantitative data for evaluation of endogenous soybean allergen content; (2) eight of the 15 potential allergens listed in the OECD soybean consensus document (Gly m 3, Gly m 4, Gly m Bd28K, Gly m Bd30K, Gly m 5, Gly m 6, Gly m 8, and Kunitz trypsin inhibitor) have both appropriate supporting clinical data and sufficient sequence information to be evaluated in comparative endogenous soybean allergen studies; and (3) the remaining seven proteins (Gly m 1, Gly m 2, unknown 50kDa protein, unknown 39kDa protein, P-22-25, lipoxygenase and lectin) lack sufficient data for clear classification as confirmed allergens and/or available sequence information and should not be currently included in the measurement of endogenous soybean allergens in the compositional analysis for the EU

  12. High performance computing and communications: FY 1997 implementation plan

    SciTech Connect

    1996-12-01

    The High Performance Computing and Communications (HPCC) Program was formally authorized by passage, with bipartisan support, of the High-Performance Computing Act of 1991, signed on December 9, 1991. The original Program, in which eight Federal agencies participated, has now grown to twelve agencies. This Plan provides a detailed description of the agencies` FY 1996 HPCC accomplishments and FY 1997 HPCC plans. Section 3 of this Plan provides an overview of the HPCC Program. Section 4 contains more detailed definitions of the Program Component Areas, with an emphasis on the overall directions and milestones planned for each PCA. Appendix A provides a detailed look at HPCC Program activities within each agency.

  13. Multiply-agile encryption in high speed communication networks

    SciTech Connect

    Pierson, L.G.; Witzke, E.L.

    1997-05-01

    Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.

  14. High temperature superconductor analog electronics for millimeter-wavelength communications

    NASA Technical Reports Server (NTRS)

    Romanofsky, R. R.; Bhasin, K. B.

    1991-01-01

    The performance of high temperature superconductor (HTS) passive microwave circuits up to X-band was encouraging when compared to their metallic counterparts. The extremely low surface resistance of HTS films up to about 10 GHz enables a reduction in loss by as much as 100 times compared to copper when both materials are kept at about 77 K. However, a superconductor's surface resistance varies in proportion to the frequency squared. Consequently, the potential benefit of HTS materials to millimeter-wave communications requires careful analysis. A simple ring resonator was used to evaluate microstrip losses at Ka-band. Additional promising components were investigated such as antennas and phase shifters. Prospects for HTS to favorable impact millimeter-wave communications systems are discussed.

  15. Java-based communication in a High Performance Computing environment

    NASA Astrophysics Data System (ADS)

    Fries, A.; de Mora, J. Portell I.; Sirvent, R.

    2011-02-01

    Java is one of the most widely used computer programming languages, however its use in High Performance Computing (HPC) is relatively low. A typical HPC environment consists of a number of multi-core computing nodes, while a typical application running in such an environment will normally contain CPU intensive code that can be executed in parallel. Such an application may require inter-node as well as intra-node communication. Message Passing Interface (MPI) is a language independent specification of an API to allow such communication. MPJExpress (Baker et al. 2006) and F-MPJ (Taboada et al. 2009) are Java-based implementations of MPI, designed with the efficient performance of data transfers as a main objective. In this paper we discuss the scalability of one approach of distributing data to compute nodes in HPC and we propose the design of an alternative data transfer system, building upon MPI.

  16. A wideband propagation simulator for high speed mobile radio communications

    NASA Astrophysics Data System (ADS)

    Busson, P.; Lejannic, J. C.; Elzein, G.; Citerne, J.

    1994-07-01

    Multipath, jamming, listening and detection are the main limitations for mobile radio communications. Spread spectrum techniques, especially frequency hopping, can be used to avoid these problems. Therefore, a wideband simulation for multipath mobile channels appeared the most appropriate evaluation technique. It also gives useful indications for system characteristic improvements. This paper presents the design and realization of a new UHF-VHF propagation simulator, which can be considered as an extended version of Bussgang's one. This frequency hopping simulator (up to 100,000 hops per second) is wideband thus capable to deal with spread spectrum signals. As it generates up to 16 paths, it can be used in almost all mobile radio propagation situations. Moreover, it is also able to simulate high mobile relative speeds up to 2000km/h such as air-air communication systems. This simulator can reproduce, in laboratory, 16 rays Rician or Rayleigh fading channels with a maximum time delay of about 15 ms. At the highest frequency of 1200 MHz, Doppler rates up to 2 kHz can be generated corresponding to vehicle speeds up to 2000 km/h. Let note that the Bussgang simulator was defined for narrowband and fixed radio communications. In both equipments, in-phase and quadrature signals are obtained using two numerical transversal filters. Simulation results were derived in various situations especially in terrestrial urban and suburban environments, where they could be compared with measurements. The main advantage of the simulator lies in its capacity to simulate the high speed and wideband mobile radio communication channels.

  17. Ultra-high speed communications based on solitons in fibers

    NASA Astrophysics Data System (ADS)

    Hasegawa, Akira

    2000-10-01

    The citation of the Maxwell prize reads: ``For innovative discoveries and seminal contributions to the theories of nonlinear drift wave turbulence, Alfvén wave propagation in laboratory and space plasmas, and optical solitons and their application to high speed communication". The prize is given to three somewhat unrelated contributions made during the course of my career as a plasma physicist. Traditionally an award talk summarizes works related to the citation. However, because of the diversified contents of the citations, I prepared my talk with the focus only on the last topic because some of the audience may be of more expertise on the other subjects. I apologize for the fact that the talk may be worth only one third of the prize. Multi-Terabits’s, ultra-high speed optical transmissions over several thousand kilometers on fibers are becoming reality and are expected to serve as the trunk line for highly demanded Internet traffics. Most of them use soliton or soliton-like RZ (Return to Zero) format in fibers with properly managed (group velocity) dispersion. These formats are the only stable envelope waveforms of light waves in fibers in the presence of Kerr (cubic) nonlineariy and dispersion with loss compensated by periodic optical amplifications. In practice, the transmission systems utilize the all-optical transmission concept and the nonlinear Schrodinger equation assisted by the split step numerical solutions as the master equation to describe the information transfer in fibers. All these facts are the outcome of research on optical solitons in fibers. The talk presents a brief historical development of the soliton based high-speed communications followed by current status of ultra-high speed communications by means of solitons as well as by other formats. Although the talk may not be of a core interest of plasma physics community, it presents an interesting example of a useful by-product of plasma physics research.

  18. Emerging applications of high temperature superconductors for space communications

    NASA Technical Reports Server (NTRS)

    Heinen, Vernon O.; Bhasin, Kul B.; Long, Kenwyn J.

    1990-01-01

    Proposed space missions require longevity of communications system components, high input power levels, and high speed digital logic devices. The complexity of these missions calls for a high data bandwidth capacity. Incorporation of high temperature superconducting (HTS) thin films into some of these communications system components may provide a means of meeting these requirements. Space applications of superconducting technology has previously been limited by the requirement of cooling to near liquid helium temperatures. Development of HTS materials with transition temperatures above 77 K along with the natural cooling ability of space suggest that space applications may lead the way in the applications of high temperature superconductivity. In order for HTS materials to be incorporated into microwave and millimeter wave devices, the material properties such as electrical conductivity, current density, surface resistivity and others as a function of temperature and frequency must be well characterized and understood. The millimeter wave conductivity and surface resistivity were well characterized, and at 77 K are better than copper. Basic microwave circuits such as ring resonators were used to determine transmission line losses. Higher Q values than those of gold resonator circuits were observed below the transition temperature. Several key HTS circuits including filters, oscillators, phase shifters and phased array antenna feeds are feasible in the near future. For technology to improve further, good quality, large area films must be reproducibly grown on low dielectric constant, low loss microwave substrates.

  19. Terahertz oscillators and receivers using electron devices for high-capacity wireless communication

    NASA Astrophysics Data System (ADS)

    Suzuki, Safumi; Asada, Masahiro

    2015-05-01

    Recent progress in room-temperature resonant-tunneling-diode (RTD) terahertz (THz) oscillators and high-electron-mobility- transistor (HEMT) THz receivers is reported in this paper. In this study, oscillations up to 1.86 THz were obtained using an optimized antenna and RTD. Using a two-element oscillator array, high output power of 0.6 mW at 620 GHz was obtained. THz communication up to 3 Gbps was demonstrated. A structure for high-speed direct modulation was fabricated, and the intensity modulation up to 30 GHz was achieved. A novel oscillator structure was proposed and fabricated for extraction of output power without using a Si lens. A short-gate InGaAs HEMT detector integrated with a broadband bow-tie antenna was fabricated, and a high current sensitivity of ~5 A/W was obtained at 280 GHz.

  20. Short communication: Association of disease incidence and adaptive immune response in Holstein dairy cows.

    PubMed

    Thompson-Crispi, K A; Hine, B; Quinton, M; Miglior, F; Mallard, B A

    2012-07-01

    The objective of this study was to use previously calculated estimated breeding values for cell- (CMIR) and antibody-mediated immune responses (AMIR) to determine associations between immune response (IR) and economically important diseases of dairy cattle. In total, 699 Holsteins were classified as high, average, or low for CMIR, AMIR, and overall IR (combined CMIR and AMIR), and associations with mastitis, metritis, ketosis, displaced abomasums, and retained fetal membranes were determined. The incidence of mastitis was higher among average cows as compared with cows classified as high AMIR [odds ratio (OR)=2.5], high CMIR (OR=1.8), or high IR (OR=1.8). Low-CMIR cows had a higher incidence of metritis (OR=11.3) and low-IR cows had a higher incidence of displaced abomasum (OR=4.1) and retained fetal membrane (OR=2.8) than did average responders. Results of this study show that cows classified as high immune responders have lower occurrence of disease, suggesting that breeding cattle for enhanced IR may be a feasible approach to decrease the incidence of infectious and metabolic diseases in the dairy industry. PMID:22720943

  1. High frequency sound attenuation in short flow ducts

    NASA Technical Reports Server (NTRS)

    Posey, J. W.

    1978-01-01

    A geometrical acoustics approach is proposed as a practical design tool for absorbent liners in such short flow ducts as may be found in turbofan engine nacelles. As an example, a detailed methodology is presented for three different types of sources in a parallel plate duct containing uniform ambient flow. A plane wave whose wavefronts are not normal to the duct walls, an arbitrarily located point source, and a spatially harmonic line source are each considered. Optimal wall admittance distributions are found, and it is shown how to estimate the insertion loss for any admittance distribution. The extension of the methodology to realistic source distributions in variable area cylindrical or annular ducts containing arbitrary flow is shown to be conceptually straightforward and computationally practical on a vector-hardware digital computer.

  2. Short Communication: Variance estimates among herds stratified by individual herd heritability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to compare genetic parameter estimates among herds stratified by high, medium and low individual herd heritability estimates. A regression model was applied to milk yield, fat yield, protein yield and somatic cell score (SCS) records from 20,902 herds to generate indi...

  3. Short Communication: Evidence for non-Gaussian distribution of rock weathering rates

    NASA Astrophysics Data System (ADS)

    Emmanuel, S.

    2015-09-01

    The weathering of rocks influences the geochemistry of the oceans, the erosion of landscapes and man-made structures, and even the global climate. Although a high degree of variance is often observed in rate measurements, little is understood about the statistical characteristics of weathering rate distributions. This preliminary study demonstrates that the weathering rates of limestone, determined from measurements of an ancient eroded limestone edifice, can exhibit highly non-Gaussian behavior. While a Gaussian model produced a poor fit with the data, an alternative model - the generalized extreme value (GEV) framework - was capable of capturing the asymmetric long-tailed distribution, in good agreement with the measured curve. Furthermore, the non-Gaussian distribution of these field rates was found to have similar characteristics to the distribution of rates measured over much smaller microscopic regions of limestone surfaces in laboratory experiments. Such similar behavior could be indicative of analogous chemical and mechanical weathering processes acting over a range of spatial and temporal scales. Moreover, highly asymmetric rate distributions with high variance could be characteristic of rates not only in carbonate rocks, but also in other rock types, suggesting that the use of a small number of measurements to determine field weathering rates may be insufficient to fully characterize the range of rates in natural systems.

  4. Short communication: genetic evaluation of stillbirth in US Brown Swiss and Jersey cattle.

    PubMed

    Yao, C; Weigel, K A; Cole, J B

    2014-01-01

    Stillbirth (SB) often results in reduced milk yield, compromised reproductive performance, and decreased dam longevity. Corrective mating can be used as a short-term solution to the problem, but long-term improvement of the population requires the routine calculation of genetic evaluations. Breeding values for SB have been available for Holstein (HO) bulls since 2006, but not for Brown Swiss (BS) or Jersey (JE) bulls. In this study, a multi-breed sire-maternal grandsire threshold model was used to perform genetic evaluations for SB of BS, JE, and HO bulls using more than 14 million purebred and crossbred calving records. Phenotypically, the percentage of SB (%SB) across all lactations were 3.7% in JE, 5.1% in BS, and 6.3% in HO. Direct heritabilities for BS, JE, and HO were 0.008, 0.007, and 0.008, and maternal heritabilities were 0.002, 0.016, and 0.021, respectively. Compared with HO, crossbred calvings from BS and JE bulls bred to HO cows lowered %SB by 1.5 and 1.2%, respectively. In general, %SB increased considerably as calving difficulty increased in all 3 breeds; however, in JE, %SB was constant for dystocia scores of 3 (needed assistance), 4 (considerable force), and 5 (extreme difficulty). Compared with purebred HO calvings, purebred BS and JE calvings had lower phenotypic %SB by up to 5.5 and 7.8%, respectively, and BS × HO and JE × HO crossbred calvings decreased %SB by up to 3.8 and 4.1%, respectively. As expected, SB rates in primiparous cows were higher than those in multiparous cows. Female calves had greater %SB than male calves in all parities for JE and in second-and-later parities for BS. Favorable (decreasing) phenotypic and genetic trends from 1999 to 2009 were observed in all 3 breeds. Heterosis of SB for BS and JE was -0.026 and -0.149, respectively, on the underlying scale, which corresponds to effects on service-sire SB (SSB) and daughter SB (DSB) predicted transmitting ability (PTA) of -0.3 and -0.5% in BS, and -1.5 and -2.7% in JE

  5. Short Communication: Cheminformatics Analysis to Identify Predictors of Antiviral Drug Penetration into the Female Genital Tract

    PubMed Central

    Thompson, Corbin G.; Sedykh, Alexander; Nicol, Melanie R.; Muratov, Eugene; Fourches, Denis; Tropsha, Alexander

    2014-01-01

    Abstract The exposure of oral antiretroviral (ARV) drugs in the female genital tract (FGT) is variable and almost unpredictable. Identifying an efficient method to find compounds with high tissue penetration would streamline the development of regimens for both HIV preexposure prophylaxis and viral reservoir targeting. Here we describe the cheminformatics investigation of diverse drugs with known FGT penetration using cluster analysis and quantitative structure–activity relationships (QSAR) modeling. A literature search over the 1950–2012 period identified 58 compounds (including 21 ARVs and representing 13 drug classes) associated with their actual concentration data for cervical or vaginal tissue, or cervicovaginal fluid. Cluster analysis revealed significant trends in the penetrative ability for certain chemotypes. QSAR models to predict genital tract concentrations normalized to blood plasma concentrations were developed with two machine learning techniques utilizing drugs' molecular descriptors and pharmacokinetic parameters as inputs. The QSAR model with the highest predictive accuracy had R2test=0.47. High volume of distribution, high MRP1 substrate probability, and low MRP4 substrate probability were associated with FGT concentrations ≥1.5-fold plasma concentrations. However, due to the limited FGT data available, prediction performances of all models were low. Despite this limitation, we were able to support our findings by correctly predicting the penetration class of rilpivirine and dolutegravir. With more data to enrich the models, we believe these methods could potentially enhance the current approach of clinical testing. PMID:24512359

  6. A high gain antenna system for airborne satellite communication applications

    NASA Technical Reports Server (NTRS)

    Maritan, M.; Borgford, M.

    1990-01-01

    A high gain antenna for commercial aviation satellites communication is discussed. Electromagnetic and practical design considerations as well as candidate systems implementation are presented. An evaluation of these implementation schemes is given, resulting in the selection of a simple top mounted aerodynamic phased array antenna with a remotely located beam steering unit. This concept has been developed into a popular product known as the Canadian Marconi Company CMA-2100. A description of the technical details is followed by a summary of results from the first production antennas.

  7. High integration microcontroller yields total vehicle communication solution

    SciTech Connect

    Arnett, D.J.; Tucker, M.J.

    1985-01-01

    Vehicle control needs are consistently increasing to meet customer performance and cost requirements. As a result, single processor systems have expanded to multiple controller solutions. With the advent of distributed processing, high speed efficient data communication methods are required. Intel's single device solution provides an innovative answer for these needs. This paper describes the architectural features of the Intel 8044 microcontroller and shows its strengths in a total networked vehicle powertrain control application, including: spark, fuel, transmission and road-to-surface traction control.

  8. Communication.

    ERIC Educational Resources Information Center

    Online-Offline, 1998

    1998-01-01

    This theme issue on communication includes annotated listings of Web sites, CD-ROM and computer software, videos, books, and professional resources that deal with various methods of communication. Sidebars discuss mythology, photojournalism, sharing ideas on the Web, and songs of protest. Suggestions for class activities are also included. (LRW)

  9. Short communication: in vitro assessment of antioxidant, antibacterial and phytochemical analysis of peel of Citrus sinensis.

    PubMed

    Mehmood, Basharat; Dar, Kamran Khurshid; Ali, Shaukat; Awan, Uzma Azeem; Nayyer, Abdul Qayyum; Ghous, Tahseen; Andleeb, Saiqa

    2015-01-01

    Antibacterial effect of Citrus sinensis peel extracts was evaluated against several pathogenic bacteria associated with human and fish infections viz., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Streptococcus pyogenes, Staphylococcus epidermidis, Serratia marcesnces, Shigella flexneri, Enterobacter amnigenus, Salmonella Typhimurium and Serratia odorifera. Methanol, ethanol, chloroform and diethyl ether solvents were used for extraction. In vitro antibacterial activity was analyzed by agar well and agar disc diffusion methods. It was found that ethanol extract showed highly significant inhibition of E. coli and K. pneumonia (12.6±0.94 mm and 11.6±1.2 mm) whereas methanol extract of C. sinensis also showed high zone of inhibition of S. odorifera (10.0±2.16 mm). The potential activity of active extracts was assessed and also compared with standard antibiotics through activity index formulation. The order of antioxidant activity through ABTS·+ and DPPH free radical scavenging activity was ethanol>methanol>chloroform>diethyl ether. Phytochemical screening of all solvents had determined the presence of terpenoids, alkaloids, steroids, glycosides and flavonoids. It was also found that Chloroform/Methanol (5:5) and Butanol/Ethanol/Water (4:1:2.2) solvent systems showed significant separation of active phytochemical constituents. These findings reveal the potential use of C. sinensis peel to treat infectious diseases, which are being caused by microorganisms. PMID:25553700

  10. Communication

    NASA Technical Reports Server (NTRS)

    Griner, James

    2010-01-01

    NASA s communication work for the UAS Command and Control area will build upon work currently being conducted under NASA Recovery Act funds. Communication portions of UAS NextGen ConOps, Stateof- the-Art assessment, and Gap Analysis. Preliminary simulations for UAS CNPC link scalability assessment. Surrogate UAS aircraft upgrades. This work will also leverage FY10 in-guide funding for communication link model development. UAS are currently managed through exceptions and are operating using DoD frequencies for line-of-sight (LOS) and satellite-based communications links, low-power LOS links in amateur bands, or unlicensed Instrument/Scientific/Medical (ISM) frequencies. None of these frequency bands are designated for Safety and Regularity of Flight. No radio-frequency (RF) spectrum has been allocated by the International Telecommunications Union (ITU) specifically for UAS command and control links, for either LOS or Beyond LOS (BLOS) communication.

  11. High power microwave components for space communications satellite

    NASA Technical Reports Server (NTRS)

    Jankowski, H.; Geia, A.

    1972-01-01

    Analyzed, developed, and tested were high power microwave components for communications satellites systems. Included were waveguide and flange configurations with venting, a harmonic filter, forward and reverse power monitors, electrical fault sensors, and a diplexer for two channel simultaneous transmission. The assembly of 8.36 GHz components was bench tested, and then operated for 60 hours at 3.5 kW CW in a high vacuum. The diplexer was omitted from this test pending a modification of its end irises. An RF leakage test showed only that care is required at flange junctions; all other components were RF tight. Designs were extrapolated for 12 GHz and 2.64 GHz high power satellite systems.

  12. Short communication: Telomere lengths in different tissues of dairy cows during early and late lactation.

    PubMed

    Laubenthal, L; Hoelker, M; Frahm, J; Dänicke, S; Gerlach, K; Südekum, K-H; Sauerwein, H; Häussler, S

    2016-06-01

    Telomeres create a protective cap on the ends of chromosomes that shorten with cell division and are influenced by stressful conditions. With the onset of lactation, high-yielding dairy cows are exposed to metabolic stress. In the present study, we aimed to analyze telomere length (TL) in key metabolic organs, such as liver, subcutaneous (sc) adipose tissue (AT), and mammary gland, as well as in peripheral blood cells during early and late lactation in German Holstein cows (n=21). Animals were fed according to their requirement, and biopsies from scAT, liver, and mammary gland as well as blood cells were collected in early and late lactation. The relative quantity of telomere products (qT), which is proportional to the average TL, was determined in genomic DNA by multiplex quantitative PCR. In this study, relative qT varied widely in the investigated tissues and blood. In late lactation, slowly proliferating tissues, such as liver and scAT, had the highest qT, whereas peripheral blood cells and in the mammary gland had the lowest qT. Comparing early with late lactation, relative qT attrition was limited to blood and mammary gland. Relationships between relative qT in blood, mammary gland, scAT, and liver suggest that blood qT might serve as a surrogate marker for tissue-specific qT. Cows with high initial qT in tissues and blood in early lactation had greater qT attrition during the course of lactation than cows with lower qT. The determination of qT could be included when phenotyping dairy cattle to test for associations with performance and fitness traits. PMID:26995138

  13. Short communication-Evaluation of antianxiety and antidepressant properties of Carthamus tinctorius L. (Safflower) petal extract.

    PubMed

    Qazi, Nasreen; Khan, Rafeeq Alam; Rizwani, Ghazala H

    2015-05-01

    Nowadays anxiety and depression are most commonly encountered diseases. They are not only difficult to diagnose but even difficult to treat since both are sometimes seen together or one predisposes the other. Apart from this side effect profile of these drugs is also high; hence there is immense scope for the herbal drugs to treat these disorders. Present study was therefore performed to evaluate the antianxiety and antidepressant effect of Carthamus tinctorius petal extract. 28 white albino rats bred in the animal house of Department of Pharmacology, University of Karachi weighing 180-220gm were randomly divided into four groups (n=7/group) to assess behavioral effects. The anxiolytic and antidepressant effects of Carthamus tinctorius petal extract were evaluated using elevated plus maize and forced swim test respectively at100 and 200mg/kg. These effects were compared with standard drugs Diazepam (anxiolytic) 2mg/kg and Nortriptyline (antidepressant) 12.5mg/kg. Results show that CT produced highly significant anxiolytic and anti-depressant effects at both doses as compared to control, similar to standard anxiolytic and antidepressant drugs diazepam and nortriptyline. It increased the latency of first entry to closed arms and the time spent in open arms very significantly at both doses while entries to open arm were increased significantly at 100mg/kg and very significantly at 200mg/kg in EPM test and increased the immobility time very significantly in FST. Hence it can be concluded that CT may be used as an alternative therapeutic agent while treating patients with anxiety and depressive disorders. PMID:26004733

  14. Radio Synthesis Imaging - A High Performance Computing and Communications Project

    NASA Astrophysics Data System (ADS)

    Crutcher, Richard M.

    The National Science Foundation has funded a five-year High Performance Computing and Communications project at the National Center for Supercomputing Applications (NCSA) for the direct implementation of several of the computing recommendations of the Astronomy and Astrophysics Survey Committee (the "Bahcall report"). This paper is a summary of the project goals and a progress report. The project will implement a prototype of the next generation of astronomical telescope systems - remotely located telescopes connected by high-speed networks to very high performance, scalable architecture computers and on-line data archives, which are accessed by astronomers over Gbit/sec networks. Specifically, a data link has been installed between the BIMA millimeter-wave synthesis array at Hat Creek, California and NCSA at Urbana, Illinois for real-time transmission of data to NCSA. Data are automatically archived, and may be browsed and retrieved by astronomers using the NCSA Mosaic software. In addition, an on-line digital library of processed images will be established. BIMA data will be processed on a very high performance distributed computing system, with I/O, user interface, and most of the software system running on the NCSA Convex C3880 supercomputer or Silicon Graphics Onyx workstations connected by HiPPI to the high performance, massively parallel Thinking Machines Corporation CM-5. The very computationally intensive algorithms for calibration and imaging of radio synthesis array observations will be optimized for the CM-5 and new algorithms which utilize the massively parallel architecture will be developed. Code running simultaneously on the distributed computers will communicate using the Data Transport Mechanism developed by NCSA. The project will also use the BLANCA Gbit/s testbed network between Urbana and Madison, Wisconsin to connect an Onyx workstation in the University of Wisconsin Astronomy Department to the NCSA CM-5, for development of long

  15. High-rate-long-distance fiber-optic communication based on advanced modulation techniques.

    PubMed

    Ivankovski, Y; Mendlovic, D

    1999-09-10

    The presence of fiber attenuation and chromatic dispersion is one of the major design aspects of fiber-optic communication systems when one addresses high-rate and long-distance digital data transmission. Conventional digital communication systems implement a modulation technique that generates light pulses at the fiber input end and tries to detect them at the fiber output end. Here an advanced modulation transmission system is developed based on knowledge of the exact dispersion parameters of the fiber and the principles of space-time mathematical analogy. The information encodes the phase of the input light beam (a continuous laser beam). This phase is designed such that, when the signal is transmitted through a fiber with a given chromatic dispersion, high peak pulses emerge at the output, which follows a desired bit pattern. Thus the continuous input energy is concentrated into short time intervals in which the information needs to be represented at the output. The proposed method provides a high rate-distance product even for fibers with high dispersion parameters, high power at the output, and also unique protection properties. Theoretical analysis of the proposed method, computer simulations, and some design aspects are given. PMID:18324062

  16. Demonstration of high-rate laser communications from fast airborne platform: flight campaign and results

    NASA Astrophysics Data System (ADS)

    Moll, Florian; Mitzkus, Wolfgang; Horwath, Joachim; Shrestha, Amita; Brechtelsbauer, Martin; Martin, Luis; Lozano, Alberto; Diaz Gonzalez, Dionisio

    2014-10-01

    Some current and future airborne payloads like high resolution cameras and radar systems need high channel capacity to transmit their data from air to ground in near real-time. Especially in reconnaissance and surveillance missions, it is important to downlink huge amount of data in very short contact times to a ground station during a flyby. Aeronautical laser communications can supply the necessary high data-rates for this purpose. Within the project DODfast (Demonstration of Optical Data link fast) a laser link from a fast flying platform was demonstrated. The flight platform was a Panavia Tornado with the laser communication terminal installed in an attached avionic demonstrator pod. The air interface was a small glass dome protecting the beam steering assembly. All other elements were integrated in a small box inside the Pod's fuselage. The receiver station was DLR's Transportable Optical Ground Station equipped with a free-space receiver front-end. Downlink wavelength for communication and uplink wavelength for beacon laser were chosen from the optical C-band DWDM grid. The test flights were carried out at the end of November 2013 near the Airbus Defence and Space location in Manching, Germany. The campaign successfully demonstrated the maturity and readiness of laser communication with a data-rate of 1.25 Gbit/s for aircraft downlinks. Pointing, acquisition and tracking performance of the airborne terminal and the ground station could be measured at aircraft speed up to 0.7 Mach and video data from an onboard camera has been transmitted. Link distances with stable tracking were up to 79 km and distance with data transmission over 50 km. In this paper, we describe the system architecture, the flight campaign and the results.

  17. Feasibility study to objectively assess activity and location of Hispanic preschoolers: a short communication

    PubMed Central

    O'Connor, Teresia M.; Cerin, Ester; Robles, Jessica; Lee, Rebecca E.; Kerr, Jacqueline; Butte, Nancy; Mendoza, Jason A.; Thompson, Deborah; Baranowski, Tom

    2015-01-01

    Both physical and social environmental factors influence young children's physical activity, yet little is known about where Hispanic children are more likely to be active. We assessed the feasibility of simultaneously measuring, then processing objective measures of location and physical activity among Hispanic preschool children. Preschool-aged Hispanic children (n = 15) simultaneously wore QStarz BT100X global positioning system (GPS) data loggers and Actigraph GT3X accelerometers for a 24- to 36-hour period, during which time their parents completed a location and travel diary. Data were aggregated to the minute and processed using the personal activity location measurement system (PALMS). Children successfully wore the GPS data loggers and accelerometers simultaneously, 12 of which yielded data that met quality standards. The average percent correspondence between GPS- and diary-based estimates of types of location was high and Kappa statistics were moderate to excellent, ranging from 0.49-0.99. The between-method (GPS monitor, parent-reported diary) correlations of estimated participant-aggregated minutes spent on vehicle-based trips were strong. The simultaneous use of GPS and accelerometers to assess Hispanic preschool children's location and physical activity is feasible. This methodology has the potential to provide more precise findings to inform environmental interventions and policy changes to promote physical activity among Hispanic preschool children. PMID:23733298

  18. Short communication: rapid detection of milk fat adulteration with vegetable oil by fluorescence spectroscopy.

    PubMed

    Ntakatsane, M P; Liu, X M; Zhou, P

    2013-04-01

    This study assessed the potential application of fluorescence spectroscopy in detecting adulteration of milk fat with vegetable oil and characterizing the samples according to the source of the fat. Pure butterfat was adulterated with different vegetable oils at various concentrations (0, 5, 10, 15, 20, 30, and 40%). Nonfat and reduced-fat milk were also adulterated with vegetable oils to simulate full-fat milk (3.2%). The 2- and 3-dimensional front-face fluorescence spectroscopy and gas chromatography were used to obtain the fluorescence spectra and fatty acid profile, respectively. Principal component analysis and 3-way partial least squares regression analysis were applied to analyze the data. The pure and adulterated samples were discriminated based on the total concentration of saturated fatty acids and unsaturated fatty acids, and also on the 3 major fluorophores: tryptophan, tocopherols, and riboflavin. Fluorescence spectroscopy was able to detect up to 5% of adulteration of vegetable oil into the butterfat. The saturated fatty acids showed higher predictability than the unsaturated fatty acids (R(2) = 0.73-0.92 vs. 0.20-0.65, respectively). The study demonstrated the high potential of fluorescence spectroscopy to rapidly detect adulteration of milk fat with vegetable oil, and discriminate commercial butter and milk according to the source of the fat. PMID:23415535

  19. Short communication: Occurrence of aflatoxin M1 in the Manchego cheese supply chain.

    PubMed

    Rubio, R; Licón, C C; Berruga, M I; Molina, M P; Molina, A

    2011-06-01

    The importance of ewe milk lies in the production of high quality cheeses, such as Manchego cheese with a Protected Designation of Origin, whose safety must be guaranteed. In a 2-yr study, 407 bulk tank milk samples from farms and 82 silo milk and curd samples from cheese factories were collected from southeast Spain and tested for aflatoxin M1 (AFM1) using 2 commercial ELISA tests. Of these, 99.3% of the bulk tank samples had AFM1 levels below the European Union (EU) legal limit for milk (50 ng/kg), and well below the limit adopted by the Codex Alimentarius (500 ng/kg). Moreover, 98.8% of the silo milk and curd samples from cheese factories had AFM1 levels below the EU limit for milk. When considering median AFM1 concentrations, an average 4-fold increase was found in the final curd in relation to the corresponding silo milk. Control of AFM1 in Manchega ewe milk would enhance dairy product safety by the possible detection of faults in the manufacture of Manchego cheese. PMID:21605747

  20. Short communication: prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis.

    PubMed

    Jamali, Hossein; Radmehr, Behrad; Ismail, Salmah

    2014-01-01

    The aims of this study were to determine the prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis in Varamin, Tehran Province, Iran. All of the isolated Staph. aureus were identified by morphology and culture and confirmed using the API Staph identification system (bioMérieux, Marcy-l'Étoile, France). Antibiotic resistance genes were detected by PCR with oligonucleotide primers specific for each gene. Staphylococcus aureus was recovered from 43 of 207 (20.1%) bovine clinical milk samples. Using disk diffusion, methicillin-resistant Staph. aureus was detected in 5 of 43 (11.6%) samples. The pathogen showed high resistance against penicillin G (86%) and tetracycline (76.7%). The blaZ (penicillin) (86%), tetM (tetracycline), and ermC (erythromycin) genes (39.5% each) were the most prevalent antibiotic resistance genes. The findings of this study are useful for designing specific control programs for bovine clinical mastitis caused by Staph. aureus in this region of Iran. PMID:24534509

  1. Short communication: Aflatoxin M₁ in dairy products sold in Şanlıurfa, Turkey.

    PubMed

    Temamogullari, F; Kanici, A

    2014-01-01

    The aim of this study was to detect the presence of aflatoxin M₁ (AFM1) in samples of raw milk (n=38), UHT milk (n=12), white pickled cheese (n=50), and yogurt (n=50) collected from the Şanlıurfa city markets and locally produced dairy products by ELISA. The mean contamination rates were 56.74 ± 40.32, 43.1 ± 23.19, 103.2 ± 29.13, and 55.28 ± 12.68 ng/kg, respectively, for raw milk, UHT milk, white pickled cheese, and yogurt. According to the data, 21 (55%) raw milk, 3 (25%) UHT milk, 10 (20%) white pickled cheese, and 10 (20%) yogurt samples were contaminated with AFM1 over the acceptable levels (≥50 ng/kg), ranging from 0.82 to 130.89 ng/kg. None of the white pickled cheese samples contained AFM1 levels above the Turkish legal limit (250 ng/kg). Consequently, the AFM1 contamination levels determined in this study in white pickled cheese were not considered to pose a serious public health hazard. However, the AFM1 levels in raw and UHT milk and yogurt samples indicate an increased human health risk in Turkey related to high aflatoxin levels. Therefore, milk and dairy products have to be monitored by the Turkish public health authorities continuously to detect AFM1 contamination. PMID:24239070

  2. Short communication: effect of milk and milk containing Lactobacillus casei on the intestinal microbiota of mice.

    PubMed

    Yin, Xiaochen; Yan, Yinzhuo; Kim, Eun Bae; Lee, Bokyung; Marco, Maria L

    2014-01-01

    BALB/c mice were fed milk or Lactobacillus casei BL23 in milk for 14d and fecal samples were collected at d 0, 4, and 7 as well as 1 and 8d after the last administration. According to high-throughput DNA sequencing of the 16S rRNA genes extracted from the fecal microbiota, the bacterial diversity in the fecal samples of all mice increased over time. After 14d of administration, the consumption of milk and milk containing L. casei BL23 resulted in distinct effects on the microbial composition in the intestine. Specifically, the proportions of bacteria in the Lactobacillaceae, Porphyromonadaceae, and Comamonadaceae were significantly higher in mice fed the L. casei BL23-milk culture compared with one or more of the other groups of mice. The relative amounts of Lachnospiraceae were higher and Streptococcaceae were lower in mice fed milk alone. The changes were not found at d 4 and 7 during milk and L. casei feeding and were no longer detected 8d after administration was stopped. This study shows that consumption of milk or probiotic L. casei-containing milk results in non-overlapping, taxa-specific effects on the bacteria in the distal murine intestine. PMID:24508432

  3. Short communication: genetic parameters for fertility-related disorders in Norwegian Red.

    PubMed

    Haugaard, Katrine; Heringstad, Bjørg

    2015-02-01

    Heritabilities and genetic correlations were estimated for the 4 most common fertility-related disorders in Norwegian Red: retained placenta, cystic ovaries, silent heat, and metritis. Data on 1,747,500 lactations from 780,114 cows calving from January 2001 through December 2011 were analyzed using multivariate threshold sire models to estimate variance components for the 4 disorders in the first 5 lactations. The traits were defined as binary within lactation (0=unaffected, 1=affected), and each fertility-related disorder was analyzed separately with the 5 lactations as correlated traits. The mean frequency of affected cows ranged from 0.5 to 1.7% for cystic ovaries, 0.7 to 1.1% for metritis, 1.3 to 3.4% for retained placenta, and 1.7 to 2.7% for silent heat. Posterior means (standard deviations) of heritability of liability ranged from 0.02 (0.01) to 0.12 (0.01), and were lowest for silent heat and highest for cystic ovaries. Genetic correlations across lactation within disorder were positive and moderate to high, ranging from 0.79 to 0.95 for cystic ovaries, 0.40 to 0.75 for metritis, 0.53 to 0.94 for retained placenta, and 0.39 to 0.83 for silent heat. PMID:25497813

  4. Short communication: Suitability of fluorescence spectroscopy for characterization of commercial milk of different composition and origin.

    PubMed

    Ntakatsane, M P; Yang, X Q; Lin, M; Liu, X M; Zhou, P

    2011-11-01

    Thirteen milk brands comprising 76 pasteurized and UHT milk samples of various compositions (whole, reduced fat, skimmed, low lactose, and high protein) were obtained from local supermarkets, and milk samples manufactured in various countries were discriminated using front-face fluorescence spectroscopy (FFFS) coupled with chemometric tools. The emission spectra of Maillard reaction products and riboflavin (MRP/RF; 400 to 600 nm) and tryptophan (300 to 400 nm) were recorded using FFFS, and the excitation wavelengths were set at 360 nm for MRP/RF and 290 nm for tryptophan. Principal component analysis (PCA) was applied to analyze the normalized spectra. The PCA of spectral information from MRP/RF discriminated the milk samples originating in different countries, and PCA of spectral information from tryptophan discriminated the samples according to composition. The fluorescence spectral data were compared with liquid chromatography-mass spectrometry results for the glycation extent of the milk samples, and a positive association (R(2)=0.84) was found between the degree of glycation of α-lactalbumin and the MRP/RF spectral data. This study demonstrates the ability and sensitivity of FFFS to rapidly discriminate and classify commercial milk with various compositions and processing conditions. PMID:22032360

  5. Age-dependent competition of porcine enterotoxigenic E. coli (ETEC) with different fimbria genes - short communication.

    PubMed

    Hur, Jin; Lee, Kyeong Min; Lee, John Hwa

    2011-12-01

    To investigate the association of pathogenic Escherichia coli fimbrial adhesins with the development of diarrhoea in piglets of different age groups and to test their relative competitiveness, piglets were orally inoculated with a mixture of E. coli strains harbouring F4, F5, F6, F18 and F41 fimbrial genes. A total of 537 E. coli strains with haemolytic activity were isolated from 36 diarrhoeic piglets. The F4 fimbrial gene was observed in 98.5%, 97.6% and 80.6% strains carrying fimbrial genes isolated from diarrhoeic piglets that were infected at 1, 3 and 5 weeks of age, respectively. These data demonstrate that F4 fimbriae are highly associated with diarrhoea in piglets of all age groups. Interestingly, the F18 fimbrial gene was observed in 2.4% and 25.4% strains carrying fimbrial genes isolated from the 3- and 5-week-old groups, respectively, which confirms that F18 fimbriae are associated with diarrhoea in piglets from late stages of suckling to post-weaning, and are more related to diarrhoea in weaned than in unweaned piglets. PMID:22079701

  6. Short communication: oral lesions in HIV/AIDS patients undergoing HAART including efavirenz.

    PubMed

    Aquino-García, S I; Rivas, M A; Ceballos-Salobreña, A; Acosta-Gio, A E; Gaitán-Cepeda, L A

    2008-06-01

    Oral lesions (OL) have an important prognostic value for HIV/AIDS patients. However, the behavior of OL in HIV/AIDS patients undergoing highly active antiretroviral therapy including efavirenz (HAART/EFV) has not been documented. Our objective was to establish the prevalence of OL in HIV/AIDS patients undergoing HAART/EFV and to compare it with the prevalence of OL in patients undergoing antiretroviral therapy including a protease inhibitor (HAART/PI). Seventy-three HIV/AIDS patients undergoing antiretroviral treatment for at least for 6 months at "La Raza" Medical Center's Internal Medicine Unit (IMSS, Mexico City) were included. To detect OL, a detailed examination of oral soft tissues was performed in each patient. Patient records recorded gender, seropositivity time, route of contagion, antiretroviral therapy type and duration, CD4 lymphocyte count/ml, and viral load. Two groups were formed: 38 patients receiving HAART/EFV [two nucleoside analogue reverse transcriptase inhibitors (NARTI) plus efavirenz] and 35 patients receiving HAART/PI (two NARTIs plus one PI). OL prevalence was established in each study group. The Chi-square test was applied (p < 0.05(IC95%)). OL prevalence in the HAART/EFV group (32%) was lower (p < 0.007) than in the HAART/PI group (63%). Candidosis was the most prevalent OL in both groups. Herpes labialis, HIV-associated necrotizing periodontitis, xerostomia, hairy leukoplakia, and nonspecific oral sores were identified. The highest prevalence for all OL was found in the HAART/PI group. These findings suggest that HIV/AIDS patients undergoing HAART/EFV show a lower prevalence of oral lesions than patients undergoing HAART/PI. PMID:18507528

  7. Short communication: Ability of dogs to detect cows in estrus from sniffing saliva samples.

    PubMed

    Fischer-Tenhagen, C; Tenhagen, B-A; Heuwieser, W

    2013-02-01

    Efficient estrus detection in high-producing dairy cows is a permanent challenge for successful reproductive performance. In former studies, dogs have been trained to identify estrus-specific odor in vaginal fluid, milk, urine, and blood samples under laboratory conditions with an accuracy of more than 80%. For on-farm utilization of estrus-detection dogs it would be beneficial in terms of hygiene and safety if dogs could identify cows from the feed alley. The objective of this proof of concept study was to test if dogs can be trained to detect estrus-specific scent in saliva of cows. Saliva samples were collected from cows in estrus and diestrus. Thirteen dogs of various breeds and both sexes were trained in this study. Five dogs had no experience in scent detection, whereas 8 dogs had been formerly trained for detection of narcotics or cancer. In the training and test situation, dogs had to detect 1 positive out of 4 samples. Dog training was based on positive reinforcement and dogs were rewarded with a clicker and food for indicating saliva samples of cows in estrus. A false indication was ignored and documented in the test situation. Dogs with and without prior training were trained for 1 and 5 d, respectively. For determining the accuracy of detection, the position of the positive sample was unknown to the dog handler, to avoid hidden cues to the dog. The overall percentage of correct positive indications was 57.6% (175/304), with a range from 40 (1 dog) to 75% (3 dogs). To our knowledge, this is the first indication that dogs are able to detect estrus-specific scent in saliva of cows. PMID:23261382

  8. High performance computing and communications: FY 1995 implementation plan

    SciTech Connect

    1994-04-01

    The High Performance Computing and Communications (HPCC) Program was formally established following passage of the High Performance Computing Act of 1991 signed on December 9, 1991. Ten federal agencies in collaboration with scientists and managers from US industry, universities, and laboratories have developed the HPCC Program to meet the challenges of advancing computing and associated communications technologies and practices. This plan provides a detailed description of the agencies` HPCC implementation plans for FY 1994 and FY 1995. This Implementation Plan contains three additional sections. Section 3 provides an overview of the HPCC Program definition and organization. Section 4 contains a breakdown of the five major components of the HPCC Program, with an emphasis on the overall directions and milestones planned for each one. Section 5 provides a detailed look at HPCC Program activities within each agency. Although the Department of Education is an official HPCC agency, its current funding and reporting of crosscut activities goes through the Committee on Education and Health Resources, not the HPCC Program. For this reason the Implementation Plan covers nine HPCC agencies.

  9. Optical waveguides and structures for short haul optical communication channels within printed circuit boards

    NASA Astrophysics Data System (ADS)

    Riegel, Nicholas J.

    Optical waveguides have shown promising results for use within printed circuit boards. These optical waveguides have higher bandwidth than traditional copper transmission systems and are immune to electromagnetic interference. Design parameters for these optical waveguides are needed to ensure an optimal link budget. Modeling and simulation methods are used to determine the optimal design parameters needed in designing the waveguides. As a result, optical structures necessary for incorporating optical waveguides into printed circuit boards are designed and optimized. Embedded siloxane polymer waveguides are investigated for their use in optical printed circuit boards. This material was chosen because it has low absorption, high temperature stability, and can be deposited using common processing techniques. Two sizes of waveguides are investigated, 50 mum multimode and 4 - 9 mum single mode waveguides. A beam propagation method is developed for simulating the multimode and single mode waveguide parameters. The attenuation of simulated multimode waveguides are able to match the attenuation of fabricated waveguides with a root mean square error of 0.192 dB. Using the same process as the multimode waveguides, parameters needed to ensure a low link loss are found for single mode waveguides including maximum size, minimum cladding thickness, minimum waveguide separation, and minimum bend radius. To couple light out-of-plane to a transmitter or receiver, a structure such as a vertical interconnect assembly (VIA) is required. For multimode waveguides the optimal placement of a total internal reflection mirror can be found without prior knowledge of the waveguide length. The optimal placement is found to be either 60 microm or 150 microm away from the end of the waveguide depending on which metric a designer wants to optimize the average output power, the output power variance, or the maximum possible power loss. For single mode waveguides a volume grating coupler is

  10. Short communication: Characteristics of student success in an undergraduate physiology and anatomy course.

    PubMed

    Gwazdauskas, F C; McGilliard, M L; Corl, B A

    2014-10-01

    curvilinear and suggests that highest exam scores were at about 90-min completion time. It may be that some male students need better preparation for anatomy and physiology and their educational preparation should mimic that of female students more in terms of advance-placement biology in high school. These results suggest that biology majors might be better prepared for animal anatomy and physiology than other students. PMID:25087028

  11. Short communication: limit feeding affects behavior patterns and feeding motivation of dairy heifers.

    PubMed

    Greter, A M; Miller-Cushon, E K; McBride, B W; Widowski, T M; Duffield, T F; DeVries, T J

    2015-02-01

    The study objective was to assess the effects of limit feeding dairy heifers on behavior patterns and feeding motivation. Ten Holstein heifers (291.6±39.2d of age, weighing 324.2±61.2kg; mean ± SD) were exposed to each of 2 dietary treatments, in a random order, over 2 successive 26-d treatment periods (14-d adaptation period and a 12-d data collection period) using a crossover design: (1) a high-forage total mixed ration (TMR), provided ad libitum (CON) and (2) a low-forage TMR, limit-fed at 2.05% body weight (LF). Heifers were fed daily at 1100h and motivation to access a low-nutritive feedstuff (straw) was assessed using a push-door apparatus at 2 time points: 3h after feed delivery (1400h) and 21h after feed delivery (0800h). The amount of weight pushed, weight pushed as percentage of body weight, and latency to access the push door were recorded on 3 different days for each heifer at each time point on each treatment. When fed CON, heifers had greater dry matter intake (12.9 vs. 7.2kg/d), greater feeding time (209.3 vs. 82.4min/d), greater ruminating time (452.2 vs. 318.3min/d), and slower rates of intake (0.06 vs. 0.09kg of dry matter/min) than when fed LF. Heifers fed LF pushed more weight as a percentage of body weight at 3h (4.5 vs. 1.9%) and 21h (9.3 vs. 2.8%) after feed delivery. At both 3 and 21h after feed delivery, latency to access the door was shorter for the LF heifers compared with the CON heifers (65 vs. 145 s). These results indicate that, in addition to decreasing feeding time, limit feeding increases motivation of heifers to access a low-nutritive feedstuff, possibly due to lack of satiety resulting from lack of physical fill or insufficient time spent foraging. PMID:25497811

  12. Short communication: Comparison of estrus characteristics in Holstein heifers by 2 activity monitoring systems.

    PubMed

    Silper, B F; Madureira, A M L; Kaur, M; Burnett, T A; Cerri, R L A

    2015-05-01

    Two activity monitoring systems-Heatime (SCR Engineers Ltd., Netanya, Israel) and IceTag (IceRobotics Ltd., Edinburgh, UK)-were compared on their ability to detect and quantify estrus expression. Holstein heifers (n=57) were fitted with Heatime (HT) and IceTag (IT) sensors from 12 mo of age until confirmation of pregnancy. Upon detection of high activity by HT, ovaries were scanned by ultrasound, a blood sample was collected for analysis of plasma estradiol, and signs of estrus (clear vaginal mucus, uterine muscle tone, visual mounting activity, standing to be mounted, or rump showing signs of repeated acceptance of mounts) were recorded. Because only estrus episodes detected by HT (n=111) were further evaluated, only the positive predictive value was measured. Heifers were housed in groups of 24 in a freestall pen. Data were analyzed using Proc CORR and GLM of SAS (SAS Institute Inc., Cary, NC). The positive predictive value was 84.7% (94/111) for HT and 98.7% (74/75) for IT. Estrus duration was recorded by HT as 14.3±4.1h [mean ± standard deviation (SD)] and by IT as 15.0±4.0h; duration measurements were correlated (r=0.60). The mean duration difference was 0.74±3.52h. Recordings of onset and end of estrus by IT were 3.5±4.3h and 2.9±4.9h earlier than those by HT. The overlap in duration was 9h. Measurements of estrus intensity were correlated (r=0.63). Peak activity was 77.3±19.5 index value (approximately 7.7 SD from basal activity) on HT. The relative increase in activity measured by IT was 360±170% baseline value. Measurements of intensity and duration from HT were correlated (r=0.64) but those from IT were not (r=0.13). Plasma estradiol concentration (11.2±4.6pg/mL) was not correlated with preovulatory follicle diameter or with duration or intensity of estrus. Diameter of preovulatory follicle (15.7±2.6mm) had no correlation with duration of estrus and was only weakly correlated with intensity measured by either system. Baseline steps/hour was

  13. Short communication: Prediction of intake in dairy cows under tropical conditions.

    PubMed

    Souza, M C; Oliveira, A S; Araújo, C V; Brito, A F; Teixeira, R M A; Moares, E H B K; Moura, D C

    2014-01-01

    had the second lowest mean bias (0.42 kg/d) and RMSPE (5.8% of the observed DMI), as well as the second highest precision (ρ = 0.94) and accuracy (Cb = 0.98). The CNCPS and AFRC DMI prediction models explained 93.0 and 85.0% of the variation in DMI but underpredicted DMI by 1.8 and 1.4 kg/d, respectively. These 2 models (CNCPS and AFRC) resulted, respectively, in RMSPE of 11.3 and 10.7% of the observed DMI, with moderate to high precision (ρ = 0.81 and 0.82) and accuracy (Cb = 0.84 and 0.89). The remaining 2 models resulted in the poorest results, underpredicting DMI by 2.3 and 1.9 kg/d, with RMSPE of 22.8 and 14.9% of the observed DMI and moderate to low precision (ρ = 0.49 and 0.76) and accuracy (Cb = 0.81 and 0.86). The new model derived from the current meta-analytical approach provided the best accuracy and precision for predicting DMI in lactating dairy cows under Brazilian conditions. PMID:24731647

  14. A SHORT DESCRIPTION OF THE PLAN OF NOVA HIGH SCHOOL.

    ERIC Educational Resources Information Center

    HIERS, NAN

    THE NOVA HIGH SCHOOL IS AN EDUCATIONAL EXPERIMENT TO MAKE LEARNING AND ACHIEVEMENT INTERESTING, CHALLENGING, AND EXCITING TO THE STUDENT. THE PROGRAM IS BASED ON THE CONCEPT OF INDIVIDUAL PROGRESS WITH EMPHASIS ON QUALITY EDUCATION. FEATURES OF THE SCHOOL ENVIRONMENT INCLUDE AIR-CONDITIONING, CARPETING, MULTIPURPOSE CLASSROOMS, INDIVIDUAL STUDY…

  15. Short-term stability of high-silica glasses

    NASA Technical Reports Server (NTRS)

    Leiser, D. B.

    1981-01-01

    The devitrification characteristics of high-silica (70-90%) glasses for use in potential higher temperature coatings on advanced insulation systems for space vehicles were determined at 1260 C after 24 h. These data indicate that additives can be used to maintain the stability of these coatings relative to cristobalite formation.

  16. High voltage electrical amplifier having a short rise time

    DOEpatents

    Christie, David J.; Dallum, Gregory E.

    1991-01-01

    A circuit, comprising an amplifier and a transformer is disclosed that produces a high power pulse having a fast response time, and that responds to a digital control signal applied through a digital-to-analog converter. The present invention is suitable for driving a component such as an electro-optic modulator with a voltage in the kilovolt range. The circuit is stable at high frequencies and during pulse transients, and its impedance matching circuit matches the load impedance with the output impedance. The preferred embodiment comprises an input stage compatible with high-speed semiconductor components for amplifying the voltage of the input control signal, a buffer for isolating the input stage from the output stage; and a plurality of current amplifiers connected to the buffer. Each current amplifier is connected to a field effect transistor (FET), which switches a high voltage power supply to a transformer which then provides an output terminal for driving a load. The transformer comprises a plurality of transmission lines connected to the FETs and the load. The transformer changes the impedance and voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage.

  17. Short-pulse, high-intensity lasers at Los Alamos

    SciTech Connect

    Taylor, A.J.; Roberts, J.P.; Rodriguez, G.; Fulton, R.D.; Kyrala, G.A.; Schappert, G.T.

    1994-03-01

    Advances in ultrafast lasers and optical amplifiers have spurred the development of terawatt-class laser systems capable of delivering focal spot intensities approaching 10{sup 20} W/cm{sup 2}. At these extremely high intensities, the optical field strength is more than twenty times larger than the Bohr electric field, permitting investigations of the optical properties of matter in a previously unexplored regime. The authors describe two laser systems for high intensity laser interaction experiments: The first is a terawatt system based on amplification of femtosecond pulses in XeCl which yields 250 mJ in 275 fs and routinely produces intensifies on target in excess of 10{sup 18} W/cm{sup 2}. The second system is based on chirped pulse amplification of 100-fs pulses in Ti:sapphire.

  18. Mexican and Mexican-American Literature for the Senior High School. Short Story, Novel, Biography.

    ERIC Educational Resources Information Center

    San Jose Unified School District, CA.

    Lesson plans for Mexican and Mexican American short stories, novels, and biographies are contained in this curriculum guides designed to supplement traditional literature programs at the senior high school level. Four short stories are reproduced in full, with related lesson plans providing background information, vocabulary terms, reference…

  19. Advanced communications technology satellite high burst rate link evaluation terminal communication protocol software user's guide, version 1.0

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    1993-01-01

    The Communication Protocol Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Communication Protocol Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Communication Protocol Software allows users to control and configure the Intermediate Frequency Switch Matrix (IFSM) on board the ACTS to yield a desired path through the spacecraft payload. Besides IFSM control, the C&PM Software System is also responsible for instrument control during HBR-LET experiments, uplink power control of the HBR-LET to demonstrate power augmentation during signal fade events, and data display. The Communication Protocol Software User's Guide, Version 1.0 (NASA CR-189162) outlines the commands and procedures to install and operate the Communication Protocol Software. Configuration files used to control the IFSM, operator commands, and error recovery procedures are discussed. The Communication Protocol Software Maintenance Manual, Version 1.0 (NASA CR-189163, to be published) is a programmer's guide to the Communication Protocol Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Communication Protocol Software, computer algorithms, format representations, and computer hardware configuration. The Communication Protocol Software Test Plan (NASA CR-189164, to be published) provides a step-by-step procedure to verify the operation of the software. Included in the Test Plan is command transmission, telemetry reception, error detection, and error recovery procedures.

  20. High-altitude medicines: a short-term genotoxicity study.

    PubMed

    Ghosh, Manosij; Biswas, Dhrubojyoti; Mukherjee, Anita

    2010-08-01

    People live in the mountains distributed across the world and are exposed to reduced inspired oxygen and lower barometric pressure along with other factors that lead to high-altitude diseases. The present study was conducted to examine what extent of marketed medicines used in the management of high-altitude sickness has been tested for their genotoxic activity. Comet assay or the single-cell gel electrophoresis was utilized to evaluate genotoxicity of the six medicines on human peripheral whole blood cells and isolated lymphocytes at the concentrations 250 microg/mL, 500 microg/mL and 1 mg/mL. The comet assay endpoints included percentage Tail DNA (% Tail DNA) and olive tail moment (OTM) as they were considered to be sensitive and reliable scores across different laboratories. The results show that dexamethasone, deriphylline and furosemide can induce significant DNA damage in human whole blood and lymphocytes alike. Acetazolamide, ibuprofen and nifedipine show no genotoxic effect, neither on human whole blood nor on human lymphocytes. Taking into account the results of genotoxicity, it will be a prudent choice to restrict the use of these compounds for longer periods, until more information on the in vitro mutagenicity and in vivo genotoxicity studies are available. PMID:20504830

  1. SLIM, Short-pulse Technology for High Gradient Induction Accelerators

    SciTech Connect

    Krasnykh, A.; Kardo-Sysoev, A.; Arntz, F.; /Diversified Tech., Bedford

    2009-12-09

    The conclusions of this paper are: (1) The gradient of the SLIM-based technology is believed to be achievable in the same range as it is for the gradient of a modern rf-linac technology ({approx}100 MeV per meter). (2) The SLIM concept is based on the nsec TEM pulse mode operation with no laser or rf systems. (3) Main components of SLIM are not stressed while the energy is pumped into the induction system. Components can accept the hard environment conditions such as a radiation dose, mismatch, hard electromagnetic nose level, etc. Only for several nanoseconds the switch is OFF and produces a stress in the induction system. At that time, the delivery of energy to the beam takes place. (4) The energy in the induction system initially is storied in the magnetic field when the switch is ON. That fact makes another benefit: a low voltage power supplies can be used. The reliability of a lower voltage power supply is higher and they are cheaper. (5) The coreless SLIM concept offers to work in the MHz range of repetition rate. The induction system has the high electric efficiency (much higher than the DWA). (6) The array of lined up and activated SLIM cells is believed to be a solid state structure of novel accelerating technology. The electron-hole plasma in the high power solid state structure is precisely controlled by the electromagnetic process of a pulsed power supply.

  2. High Bandwidth Short Stroke Rotary Fast Tool Servo

    SciTech Connect

    Montesanti, R C; Trumper, D L

    2003-08-22

    This paper presents the design and performance of a new rotary fast tool servo (FTS) capable of developing the 40 g's tool tip acceleration required to follow a 5 micron PV sinusoidal surface at 2 kHz with a planned accuracy of 50 nm, and having a full stroke of 50 micron PV at lower frequencies. Tests with de-rated power supplies have demonstrated a closed-loop unity-gain bandwidth of 2 kHz with 20 g's tool acceleration, and we expect to achieve 40 g's with supplies providing {+-} 16 Amp to the Lorentz force actuator. The use of a fast tool servo with a diamond turning machine for producing non-axisymmetric or textured surfaces on a workpiece is well known. Our new rotary FTS was designed to specifically accommodate fabricating prescription textured surfaces on 5 mm diameter spherical target components for High Energy Density Physics experiments on the National Ignition Facility Laser (NIF).

  3. Short, Enantioselective Total Synthesis of Highly Oxidized Taxanes.

    PubMed

    Yuan, Changxia; Jin, Yehua; Wilde, Nathan C; Baran, Phil S

    2016-07-11

    In the realm of natural product chemistry, few isolates have risen to the level of fame justifiably accorded to Taxol (1) and its chemical siblings. This report describes the most concise route to date for accessing the highly oxidized members of this family. As representative members of taxanes containing five oxygen atoms, decinnamoyltaxinine E (2) and taxabaccatin III (3), have succumbed to enantioselective total synthesis for the first time in only 18 steps from a simple olefin starting material. The strategy holistically mimics nature's approach (two-phase synthesis) and features a carefully choreographed sequence of stereoselective oxidations and a remarkable redox-isomerization to set the key trans-diol present in 2 and 3. This work lays the critical groundwork necessary to access even higher oxidized taxanes such as 1 in a more practical fashion, thus empowering a medicinal chemistry campaign that is not wedded to semi-synthesis. PMID:27240325

  4. Functional connectivity classification of autism identifies highly predictive brain features but falls short of biomarker standards

    PubMed Central

    Plitt, Mark; Barnes, Kelly Anne; Martin, Alex

    2014-01-01

    Objectives Autism spectrum disorders (ASD) are diagnosed based on early-manifesting clinical symptoms, including markedly impaired social communication. We assessed the viability of resting-state functional MRI (rs-fMRI) connectivity measures as diagnostic biomarkers for ASD and investigated which connectivity features are predictive of a diagnosis. Methods Rs-fMRI scans from 59 high functioning males with ASD and 59 age- and IQ-matched typically developing (TD) males were used to build a series of machine learning classifiers. Classification features were obtained using 3 sets of brain regions. Another set of classifiers was built from participants' scores on behavioral metrics. An additional age and IQ-matched cohort of 178 individuals (89 ASD; 89 TD) from the Autism Brain Imaging Data Exchange (ABIDE) open-access dataset (http://fcon_1000.projects.nitrc.org/indi/abide/) were included for replication. Results High classification accuracy was achieved through several rs-fMRI methods (peak accuracy 76.67%). However, classification via behavioral measures consistently surpassed rs-fMRI classifiers (peak accuracy 95.19%). The class probability estimates, P(ASD|fMRI data), from brain-based classifiers significantly correlated with scores on a measure of social functioning, the Social Responsiveness Scale (SRS), as did the most informative features from 2 of the 3 sets of brain-based features. The most informative connections predominantly originated from regions strongly associated with social functioning. Conclusions While individuals can be classified as having ASD with statistically significant accuracy from their rs-fMRI scans alone, this method falls short of biomarker standards. Classification methods provided further evidence that ASD functional connectivity is characterized by dysfunction of large-scale functional networks, particularly those involved in social information processing. PMID:25685703

  5. Short term high density systemic therapy for metastatic breast cancer.

    PubMed

    Tormey, D C; Kline, J C; Palta, M; Davis, T E; Love, R R; Carbone, P P

    1985-01-01

    Twenty-three patients with metastatic breast carcinoma were induced with a complex systemic therapy regimen in an attempt to ascertain if a complete remission rate greater than 50% could be obtained with intensive drug exposure. The durability of the remissions was observed by discontinuing therapy after 3 cycles in complete remission or after 6 cycles of treatment, whichever was longer. In 13 patients consolidation radiation therapy to the pre-treatment sites of disease was administered after discontinuing systemic therapy. Each 28 day cycle of the drug regimen consisted of pulses of adriamycin, vincristine, dibromodulcitol, prednisone, methotrexate with leukovorin rescue, hexamethylmelamine, bleomycin (discontinued after entry #17), fluoxymesterone, and tamoxifen. Eighteen of the 23 patients achieved complete remissions (78%) and 3 had partial remissions. The median times to treatment failure and survival were, respectively, 12.3 and 19.4 mos. The times for complete remission patients were, respectively, 13.5 and 23.9 mos. Consolidation radiotherapy at greater than or equal to 40 Gy to drug induced pre-study sites of complete remission was associated with first relapses at pre-study sites in 5/30 (17%) instances, compared to 21/35 (60%) in sites not receiving radiotherapy. Side-effects were commensurate with the intensity of the treatment program and are detailed in the text. Although the achievement of a high complete remission rate is promising, the failure to extend their duration beyond that of historical data suggests that additional conceptual and therapeutic approaches need to be explored. PMID:2410072

  6. Evaluation of components, subsystems, and networks for high rate, high frequency space communications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Ivancic, William D.; Zuzek, John E.

    1991-01-01

    The development of new space communications technologies by NASA has included both commercial applications and space science requirements. NASA's Systems Integration, Test and Evaluation (SITE) Space Communication System Simulator is a hardware based laboratory simulator for evaluating space communications technologies at the component, subsystem, system, and network level, geared toward high frequency, high data rate systems. The SITE facility is well-suited for evaluation of the new technologies required for the Space Exploration Initiative (SEI) and advanced commercial systems. Described here are the technology developments and evaluation requirements for current and planned commercial and space science programs. Also examined are the capabilities of SITE, the past, present and planned future configurations of the SITE facility, and applications of SITE to evaluation of SEI technology.

  7. Evaluation of components, subsystems, and networks for high rate, high frequency space communications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Ivancic, William D.; Zuzek, John E.

    1991-01-01

    The development of new space communications technologies by NASA has included both commercial applications and space science requirements. At NASA's Lewis Research Center, methods and facilities have been developed for evaluating these new technologies in the laboratory. NASA's Systems Integration, Test and Evaluation (SITE) Space Communication System Simulator is a hardware-based laboratory simulator for evaluating space communications technologies at the component, subsystem, system, and network level, geared toward high frequency, high data rate systems. The SITE facility is well-suited for evaluation of the new technologies required for the Space Exploration Initiative (SEI) and advanced commercial systems. This paper describes the technology developments and evaluation requirements for current and planned commercial and space science programs. Also examined are the capabilities of SITE, the past, present, and planned future configurations of the SITE facility, and applications of SITE to evaluation of SEI technology.

  8. Communications

    ERIC Educational Resources Information Center

    Bailenson, Jeremy; Buzzanell, Patrice; Deetz, Stanley; Tewksbury, David; Thompson, Robert J.; Turow, Joseph; Bichelmeyer, Barbara; Bishop, M. J.; Gayeski, Diane

    2013-01-01

    Scholars representing the field of communications were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Jeremy Bailenson, Patrice Buzzanell, Stanley Deetz, David Tewksbury, Robert J. Thompson, and…

  9. Communications

    NASA Technical Reports Server (NTRS)

    Hathorn, S.

    1985-01-01

    An overview of NASA's Thin Route satellite telecommunication project is presented. Thin Route employs applications technology satellites (ATS) in place of more costly commercial multi- transponder telecommunications satellites. This system allows remote and underdeveloped areas to communicate with the outside world for purposes of obtaining medical assistance among other things. The system represents a substantial cost saving over commercial systems.

  10. The design of space optical communications terminal with high efficient

    NASA Astrophysics Data System (ADS)

    Deng, Xiaoguo; Li, Gang; Jiang, Bo; Yang, Xiaoxu; Yan, Peipei

    2015-02-01

    In order to improve high-speed laser space optical communications terminal receive energy and emission energy, meet the demand of mini-type and light-type for space-based bear platform, based on multiple-reflect coaxial optical receiving antenna structure, while considering the installation difficulty, a high-efficient optical system had been designed, which aperture is off-axial, both signal-receiving sub-optical system and emission sub-optical system share a same primary optical path. By the separating light lens behind the primary optical path, the received light with little energy will be filtered and shaped and then transmitted to each detector, at the same time, by the coupling element, the high-power laser will be coupling into optical antenna, and then emitted to outside. Applied the power-detected optical system evaluate principle, the optimized off-axial optical system's efficiency had been compared with the coaxial optical system. While, analyzed the Gauss beam energy distribution by numerical theory, discussed that whether off-axis optical system can be an emission terminal, verify the feasibility of the theory of the design of the system.

  11. An Overview of High Energy Short Pulse Technology for Advanced Radiography of Laser Fusion Experiments

    SciTech Connect

    Barty, C J; Key, M; Britten, J; Beach, R; Beer, G; Brown, C; Bryan, S; Caird, J; Carlson, T; Crane, J; Dawson, J; Erlandson, A C; Fittinghoff, D; Hermann, M; Hoaglan, C; Iyer, A; Jones, L; Jovanovic, I; Komashko, A; Landen, O; Liao, Z; Molander, W; Mitchell, A; Moses, E; Nielsen, N; Nguyen, H; Nissen, J; Payne, S; Pennington, D; Risinger, L; Rushford, M; Skulina, K; Spaeth, M; Stuart, B; Tietbohl, G; Wattellier, B

    2004-06-18

    The technical challenges and motivations for high-energy, short-pulse generation with NIF-class, Nd:glass laser systems are reviewed. High energy short pulse generation (multi-kilojoule, picosecond pulses) will be possible via the adaptation of chirped pulse amplification laser techniques on the NIF. Development of meter-scale, high efficiency, high-damage-threshold final optics is a key technical challenge. In addition, deployment of HEPW pulses on NIF is constrained by existing laser infrastructure and requires new, compact compressor designs and short-pulse, fiber-based, seed-laser systems. The key motivations for high energy petawatt pulses on NIF is briefly outlined and includes high-energy, x-ray radiography, proton beam radiography, proton isochoric heating and tests of the fast ignitor concept for inertial confinement fusion.

  12. Enhanced performance of 400 Gb/s DML-based CAP systems using optical filtering technique for short reach communication.

    PubMed

    Tao, Li; Wang, Yiguang; Xiao, Jiangnan; Chi, Nan

    2014-12-01

    A parallel transmission approach is more likely to realize 400 Gb/s and above short reach transmission as it helps to reduce the cost of both electrical and optical device largely. Directly modulated lasers (DML) are more attractive in 400 Gb/s approach, because it requires relatively small amount of driving power and has low insertion loss, thus lowering its cost. However, the intrinsic chirp will degrade the transmission performance. In this paper, an optical filtering technique is introduced for 400 Gb/s high-speed DML-based carrierless amplitude and phase (CAP) modulation short reach systems for the first time. Owing to the additional optical filter, 1 dB and 3.6 dB sensitivity improvement at BER of 3.8 x 10(-3) is obtained for the back-to-back and 15 km fiber link transmission for single lane at the bitrate of 28 Gb/s. Then a 16-lane CAP16 system with a total bit rate of 413 Gb/s is demonstrated experimentally using low-cost 10 GHz-class DML using optical filtering technique. PMID:25606867

  13. Toward High-Performance Communications Interfaces for Science Problem Solving

    NASA Astrophysics Data System (ADS)

    Oviatt, Sharon L.; Cohen, Adrienne O.

    2010-12-01

    From a theoretical viewpoint, educational interfaces that facilitate communicative actions involving representations central to a domain can maximize students' effort associated with constructing new schemas. In addition, interfaces that minimize working memory demands due to the interface per se, for example by mimicking existing non-digital work practice, can preserve students' attentional focus on their learning task. In this research, we asked the question: What type of interface input capabilities provide best support for science problem solving in both low- and high- performing students? High school students' ability to solve a diverse range of biology problems was compared over longitudinal sessions while they used: (1) hardcopy paper and pencil (2) a digital paper and pen interface (3) pen tablet interface, and (4) graphical tablet interface. Post-test evaluations revealed that time to solve problems, meta-cognitive control, solution correctness, and memory all were significantly enhanced when using the digital pen and paper interface, compared with tablet interfaces. The tangible pen and paper interface also was the only alternative that significantly facilitated skill acquisition in low-performing students. Paradoxically, all students nonetheless believed that the tablet interfaces provided best support for their performance, revealing a lack of self-awareness about how to use computational tools to best advantage. Implications are discussed for how pen interfaces can be optimized for future educational purposes, and for establishing technology fluency curricula to improve students' awareness of the impact of digital tools on their performance.

  14. 77 FR 55880 - Prudential Short Duration High Yield Fund, Inc. and Prudential Investments LLC; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... COMMISSION Prudential Short Duration High Yield Fund, Inc. and Prudential Investments LLC; Notice of... High Yield Fund, Inc. (``Initial Fund'') and Prudential Investments LLC (``PI'' or the ``Adviser... investing primarily in a diversified portfolio of high yield fixed income instruments that are rated...

  15. The Investigation of Teacher Communication Practices in Virtual High School

    ERIC Educational Resources Information Center

    Belair, Marley

    2011-01-01

    Virtual schooling is an increasing trend for secondary education. Research of the communication practices in virtual schools has provided a myriad of suggestions for virtual school policies. Although transactional distance has been investigated in relation to certain aspects of the communication process, a small-scale qualitative study has not…

  16. A short educational intervention on communication skills improves the quality of screening for Chlamydia in GPs in Belgium: a cluster randomised controlled trial.

    PubMed

    Verhoeven, Veronique; Avonts, Dirk; Vermeire, Etienne; Debaene, Luc; Van Royen, Paul

    2005-04-01

    An accurate algorithm for screening for chlamydial infections is available in general practice, but GPs experience numerous barriers to sexually transmitted infections (STI) counselling. In this study we assessed if a short educational package, under the form of a commented video footage on communication skills, was helpful in implementing the screening strategy. A cluster randomised controlled trial was carried out in 36 general practitioners in Antwerp, Belgium. Main outcome measures were: number of patients included in the risk assessment, number of patients tested, and proportion of appropriately tested patients. The results show that GPs in the intervention group did not include more patients overall, but that the quality of the screening process was significantly better (81.6% versus 56.2% appropriate tests, P = 0.02). Conclusively, GPs who participated in a short educational package on communication skills, selected eligible candidates for screening more accurately and decreased the risk of overscreening. PMID:15797158

  17. Invited Article: Polarization diversity and modulation for high-speed optical communications: architectures and capacity

    NASA Astrophysics Data System (ADS)

    Shieh, William; Khodakarami, Hamid; Che, Di

    2016-07-01

    Polarization is one of the fundamental properties of optical waves. To cope with the exponential growth of the Internet traffic, optical communications has advanced by leaps and bounds within the last decade. For the first time, the polarization domain has been extensively explored for high-speed optical communications. In this paper, we discuss the general principle of polarization modulation in both Jones and Stokes spaces. We show that there is no linear optical device capable of transforming an arbitrary input polarization into one that is orthogonal to itself. This excludes the receiver self-polarization diversity architecture by splitting the signal into two branches, and then transferring one of the branches into orthogonal polarization. We next propose a novel Stokes vector (SV) detection architecture using four single-ended photodiodes (PD) that can recover a full set of SV. We then derive a closed-form expression for the information capacity of different SV detection architectures and compare the capacity of our proposed architectures with that of intensity-modulated directly-detected (IM/DD) method. We next study the 3-PD SV detection architecture where a subset of SV is detected, and devise a novel modulation algorithm that can achieve 2-dimensional modulation with the 3-PD detection. By using cost-effective SV receivers, polarization modulation and multiplexing offers a powerful solution for short-reach optical networks where the wavelength domain is quickly exhausted.

  18. Modelling high data rate communication network access protocol

    NASA Technical Reports Server (NTRS)

    Khanna, S.; Foudriat, E. C.; Paterra, Frank; Maly, Kurt J.; Overstreet, C. Michael

    1990-01-01

    Modeling of high data rate communication systems is different from the low data rate systems. Three simulations were built during the development phase of Carrier Sensed Multiple Access/Ring Network (CSMA/RN) modeling. The first was a model using SIMCRIPT based upon the determination and processing of each event at each node. The second simulation was developed in C based upon isolating the distinct object that can be identified as the ring, the message, the node, and the set of critical events. The third model further identified the basic network functionality by creating a single object, the node which includes the set of critical events which occur at the node. The ring structure is implicit in the node structure. This model was also built in C. Each model is discussed and their features compared. It should be stated that the language used was mainly selected by the model developer because of his past familiarity. Further the models were not built with the intent to compare either structure or language but because the complexity of the problem and initial results contained obvious errors, so alternative models were built to isolate, determine, and correct programming and modeling errors. The CSMA/RN protocol is discussed in sufficient detail to understand modeling complexities. Each model is described along with its features and problems. The models are compared and concluding observations and remarks are presented.

  19. A DSP Based POD Implementation for High Speed Multimedia Communications

    NASA Astrophysics Data System (ADS)

    Zhang, Chang Nian; Li, Hua; Zhang, Nuannuan; Xie, Jiesheng

    2002-12-01

    In the cable network services, the audio/video entertainment contents should be protected from unauthorized copying, intercepting, and tampering. Point-of-deployment (POD) security module, proposed by[InlineEquation not available: see fulltext.], allows viewers to receive secure cable services such as premium subscription channels, impulse pay-per-view, video-on-demand as well as other interactive services. In this paper, we present a digital signal processor (DSP) (TMS320C6211) based POD implementation for the real-time applications which include elliptic curve digital signature algorithm (ECDSA), elliptic curve Diffie Hellman (ECDH) key exchange, elliptic curve key derivation function (ECKDF), cellular automata (CA) cryptography, communication processes between POD and Host, and Host authentication. In order to get different security levels and different rates of encryption/decryption, a CA based symmetric key cryptography algorithm is used whose encryption/decryption rate can be up to[InlineEquation not available: see fulltext.]. The experiment results indicate that the DSP based POD implementation provides high speed and flexibility, and satisfies the requirements of real-time video data transmission.

  20. Short and Long-Term Impacts of Biotechnology Education on Professionals Who Communicate Science to the Public

    ERIC Educational Resources Information Center

    Fritz, Susan M.; Ward, Sarah M.; Byrne, Pat F.; Namuth, Deana M.; Egger, Valerie A.

    2004-01-01

    Consumer acceptance or rejection of biotechnology is often shaped by information prepared by communicators with varying levels of scientific knowledge, awareness, and acceptance. This study compared the prior, post-workshop, and sustained (1 year) biotechnology awareness, acceptance, and attitudes of professionals who communicate biotechnology to…

  1. Persuading Girls to Take Elective Physical Science Courses in High School: Who Are the Credible Communicators?

    ERIC Educational Resources Information Center

    Koballa, Thomas R., Jr.

    1988-01-01

    Identifies communicators whom eighth-grade girls perceive as credible regarding reasons for taking elective physical science courses in high school. Finds that father, woman science teacher, mother, and boy high school student are ranked highly. Attributes associated with the communicators were classified as prestige, trustworthiness, similarity,…

  2. Multiplexed communication over a high-speed quantum channel

    NASA Astrophysics Data System (ADS)

    Heurs, M.; Webb, J. G.; Dunlop, A. E.; Harb, C. C.; Ralph, T. C.; Huntington, E. H.

    2010-03-01

    In quantum information systems it is of particular interest to consider the best way in which to use the nonclassical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are among the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by a comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analog band width. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4-GHz comb of vacuum squeezing produced by a subthreshold optical parametric oscillator, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel.

  3. Multiplexed communication over a high-speed quantum channel

    SciTech Connect

    Heurs, M.; Webb, J. G.; Dunlop, A. E.; Harb, C. C.; Huntington, E. H.; Ralph, T. C.

    2010-03-15

    In quantum information systems it is of particular interest to consider the best way in which to use the nonclassical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are among the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by a comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analog band width. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4-GHz comb of vacuum squeezing produced by a subthreshold optical parametric oscillator, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel.

  4. Generation of high-energy (>15 MeV) neutrons using short pulse high intensity lasers

    SciTech Connect

    Petrov, G. M.; Davis, J.; Petrova, Tz. B.; Higginson, D. P.; McNaney, J. M.; McGuffey, C.; Qiao, B.; Beg, F. N.

    2012-09-15

    A roadmap is suggested and demonstrated experimentally for the production of high-energy (>15 MeV) neutrons using short pulse lasers. Investigation with a 3D Monte Carlo model has been employed to quantify the production of energetic neutrons. Numerical simulations have been performed for three nuclear reactions, d(d,n){sup 3}He, {sup 7}Li(d,n){sup 8}Be, and {sup 7}Li(p,n){sup 7}Be, driven by monoenergetic ion beams. Quantitative estimates for the driver ion beam energy and number have been made and the neutron spectra and yield in the ion propagation direction have been evaluated for various incident ion energies. In order to generate neutron fluence above a detection limit of 10{sup 6} neutrons/sr, either {approx}10{sup 10} protons with energy 20-30 MeV or comparable amount of deuterons with energy 5-10 MeV are required. Experimental verification of the concept with deuterons driven by the Titan laser (peak intensity 2 Multiplication-Sign 10{sup 19} W/cm{sup 2}, pulse duration of 9 ps, wavelength 1.05 {mu}m, and energy of 360 J) is provided with the generation of neutrons with energy of up to 18 MeV from {sup 7}Li(d,n){sup 8}Be reactions. Future research will focus on optimized schemes for ion acceleration for production of high-energy neutrons, which will involve efficient target design, laser parameter optimization, and converter material.

  5. Very high speed optoelectronic functions for extremely high data rate communications between satellites

    NASA Astrophysics Data System (ADS)

    Folcke, Georges; Defrancq, Jean-Marc; Geffroy, Dominique; Roy, Bernard

    1998-05-01

    High data rate communications between satellites request to develop very specific electronic circuits. Very high speed, high current (more than 500 mA peak to peak) and low power consumption laser driver was realized and integrated into a specific low volume and low mass hybrid design. This paper reports also the realization of a complete receiver based on the integration of an Avalanche Photodiode (APD) into a very low noise preamplifier followed by an other hybrid module including a limiter amplifier, a clock recovery and decision circuit. The high voltage DC/DC convertor for the APD is also presented as a third hybrid circuit. Full bit rate is in the range of 622 Mbps. For the receiver, the sensitivity obtained is very closed to the theoretical possibilities. The opto- electronic modules under realization (or realized) are fiber pigtailed, with a single mode fiber on the transmitter side and a multimode fiber on the receiver side which allow their integration into the communication boxes. The present paper gives an overview of the modules development, including the main results, and situates these activities in a more complete realization of optical communication boxes.

  6. Future directions for probing two and three nucleon short-range correlations at high energies

    SciTech Connect

    Frankfurt, Leonid; Sargsian, Misak; Strikman, Mark

    2008-10-13

    We summarize recent progress in the studies of the short-rang correlations (SRC) in nuclei in high energy electron and hadron nucleus scattering and suggest directions for the future high energy studies aimed at establishing detailed structure of two-nucleon SRCs, revealing structure of three nucleon SRC correlations and discovering non-nucleonic degrees of freedom in nuclei.

  7. NASA satellite communications application research, phase 2 addendum. Efficient high power, solid state amplifier for EHF communications

    NASA Technical Reports Server (NTRS)

    Benet, James

    1994-01-01

    This document is an addendum to the NASA Satellite Communications Application Research (SCAR) Phase 2 Final Report, 'Efficient High Power, Solid State Amplifier for EHF Communications.' This report describes the work performed from 1 August 1993 to 11 March 1994, under contract number NASW-4513. During this reporting period an array of transistor amplifiers was repaired by replacing all MMIC amplifier chips. The amplifier array was then tested using three different feedhorn configurations. Descriptions, procedures, and results of this testing are presented in this report, and conclusions are drawn based on the test results obtained.

  8. Short- and long-term changes in right whale calling behavior: the potential effects of noise on acoustic communication.

    PubMed

    Parks, Susan E; Clark, C W; Tyack, P L

    2007-12-01

    The impact of anthropogenic noise on marine mammals has been an area of increasing concern over the past two decades. Most low-frequency anthropogenic noise in the ocean comes from commercial shipping which has contributed to an increase in ocean background noise over the past 150 years. The long-term impacts of these changes on marine mammals are not well understood. This paper describes both short- and long-term behavioral changes in calls produced by the endangered North Atlantic right whale (Eubalaena glacialis) and South Atlantic right whale (Eubalaena australis) in the presence of increased low-frequency noise. Right whales produce calls with a higher average fundamental frequency and they call at a lower rate in high noise conditions, possibly in response to masking from low-frequency noise. The long-term changes have occurred within the known lifespan of individual whales, indicating that a behavioral change, rather than selective pressure, has resulted in the observed differences. This study provides evidence of a behavioral change in sound production of right whales that is correlated with increased noise levels and indicates that right whales may shift call frequency to compensate for increased band-limited background noise. PMID:18247780

  9. Model of Atmospheric Links on Optical Communications from High Altitude

    NASA Technical Reports Server (NTRS)

    Subich, Christopher

    2004-01-01

    Optical communication links have the potential to solve many of the problems of current radio and microwave links to satellites and high-altitude aircraft. The higher frequency involved in optical systems allows for significantly greater signal bandwidth, and thus information transfer rate, in excess of 10 Gbps, and the highly directional nature of laser-based signals eliminates the need for frequency-division multiplexing seen in radio and microwave links today. The atmosphere, however, distorts an optical signal differently than a microwave signal. While the ionosphere is one of the most significant sources of noise and distortion in a microwave or radio signal, the lower atmosphere affects an optical signal more significantly. Refractive index fluctuations, primarily caused by changes in atmospheric temperature and density, distort the incoming signal in both deterministic and nondeterministic ways. Additionally, suspended particles, such as those in haze or rain, further corrupt the transmitted signal. To model many of the atmospheric effects on the propagating beam, we use simulations based on the beam-propagation method. This method, developed both for simulation of signals in waveguides and propagation in atmospheric turbulence, separates the propagation into a diffraction and refraction problem. The diffraction step is an exact solution, within the limits of numerical precision, to the problem of propagation in free space, and the refraction step models the refractive index variances over a segment of the propagation path. By applying refraction for a segment of the propagation path, then diffracting over that same segment, this method forms a good approximation to true propagation through the atmospheric medium. Iterating over small segments of the total propagation path gives a good approximation to the problem of propagation over the entire path. Parameters in this model, such as initial beam profile and atmospheric constants, are easily modified in a

  10. Investigation of the Effect of Sport on Submissive Behavior and Communication Skills of High School Students

    ERIC Educational Resources Information Center

    Abakay, Ugur

    2013-01-01

    This study was carried out to detect the differences in submissive behaviors and communication skills of high school students in terms of sports activities and relationship between communication skills and properties of submissive behavior of high school students who are actively involved in sports activities. In this respect at the study, 728…

  11. Ultra high frequency follow-on communications satellite system

    NASA Astrophysics Data System (ADS)

    Hassien, Michael J.

    1992-03-01

    The existing constellation of UHF communications satellites (LEASAT and FLTSAT) provide key command and control links for mobile forces of the DoD and other government agencies. The UHF Follow-On satellite program will provide for a new generation of communications satellites to replace the existing ones as they reach the end of their life cycle beginning in 1992. Continued coverage is required for both peacetime and crisis environments, and must be maintained indefinitely. An eight-satellite UFO constellation (two per coverage area) will replenish the existing FLTSATCOM constellation.

  12. Highly Efficient Amplifier for Ka-Band Communications

    NASA Technical Reports Server (NTRS)

    1996-01-01

    An amplifier developed under a Small Business Innovation Research (SBIR) contract will have applications for both satellite and terrestrial communications. This power amplifier uses an innovative series bias arrangement of active devices to achieve over 40-percent efficiency at Ka-band frequencies with an output power of 0.66 W. The amplifier is fabricated on a 2.0- by 3.8-square millimeter chip through the use of Monolithic Microwave Integrated Circuit (MMIC) technology, and it uses state-of-the-art, Pseudomorphic High-Electron-Mobility Transistor (PHEMT) devices. Although the performance of the MMIC chip depends on these high-performance devices, the real innovations here are a unique series bias scheme, which results in a high-voltage chip supply, and careful design of the on-chip planar output stage combiner. This design concept has ramifications beyond the chip itself because it opens up the possibility of operation directly from a satellite power bus (usually 28 V) without a dc-dc converter. This will dramatically increase the overall system efficiency. Conventional microwave power amplifier designs utilize many devices all connected in parallel from the bias supply. This results in a low-bias voltage, typically 5 V, and a high bias current. With this configuration, substantial I(sup 2) R losses (current squared times resistance) may arise in the system bias-distribution network. By placing the devices in a series bias configuration, the total current is reduced, leading to reduced distribution losses. Careful design of the on-chip planar output stage power combiner is also important in minimizing losses. Using these concepts, a two-stage amplifier was designed for operation at 33 GHz and fabricated in a standard MMIC foundry process with 0.20-m PHEMT devices. Using a 20-V bias supply, the amplifier achieved efficiencies of over 40 percent with an output power of 0.66 W and a 16-dB gain over a 2-GHz bandwidth centered at 33 GHz. With a 28-V bias, a power

  13. Forecasting the Short-Term Passenger Flow on High-Speed Railway with Neural Networks

    PubMed Central

    Xie, Mei-Quan; Li, Xia-Miao; Zhou, Wen-Liang; Fu, Yan-Bing

    2014-01-01

    Short-term passenger flow forecasting is an important component of transportation systems. The forecasting result can be applied to support transportation system operation and management such as operation planning and revenue management. In this paper, a divide-and-conquer method based on neural network and origin-destination (OD) matrix estimation is developed to forecast the short-term passenger flow in high-speed railway system. There are three steps in the forecasting method. Firstly, the numbers of passengers who arrive at each station or depart from each station are obtained from historical passenger flow data, which are OD matrices in this paper. Secondly, short-term passenger flow forecasting of the numbers of passengers who arrive at each station or depart from each station based on neural network is realized. At last, the OD matrices in short-term time are obtained with an OD matrix estimation method. The experimental results indicate that the proposed divide-and-conquer method performs well in forecasting the short-term passenger flow on high-speed railway. PMID:25544838

  14. An Investigation of Communication in Virtual High Schools

    ERIC Educational Resources Information Center

    Belair, Marley

    2012-01-01

    Virtual schooling is an increasing trend for secondary education. Research of the communication practices in virtual schools has provided a myriad of suggestions for virtual school policies. The purpose of this qualitative study was to investigate the activities and processes involved in the daily rituals of virtual school teachers and learners…

  15. Toward High-Performance Communications Interfaces for Science Problem Solving

    ERIC Educational Resources Information Center

    Oviatt, Sharon L.; Cohen, Adrienne O.

    2010-01-01

    From a theoretical viewpoint, educational interfaces that facilitate communicative actions involving representations central to a domain can maximize students' effort associated with constructing new schemas. In addition, interfaces that minimize working memory demands due to the interface per se, for example by mimicking existing non-digital work…

  16. High-Tech PR: Five Case Studies in Computerized Communication.

    ERIC Educational Resources Information Center

    Malaspina, Rick; And Others

    1993-01-01

    Use of computer technology for specialized communication networks at University of California (Oakland), Lafayette College (Pennsylvania), Carnegie Mellon University (Pennsylvania), the University of Wisconsin at Eau Claire, and the State University of New York at Stony Brook is described. The systems feature different forms of internal and…

  17. When Are High-Tech Communicators Effective in Parkinson's Disease?

    ERIC Educational Resources Information Center

    Ferriero, Giorgio; Caligari, Marco; Ronconi, Gianpaolo; Franchignoni, Franco

    2012-01-01

    This report describes a 63-year-old woman with Parkinson's disease showing loss of intelligibility of speech and severely impaired handwriting, despite undergoing physical and speech therapies. As the patient had sufficient residual motor abilities and adequate cognitive function and motivation, a computer-based communication aid with a software…

  18. Short communication: Strengthening sub-national communicable disease surveillance in a remote Pacific Island country by adapting a successful African outbreak surveillance model.

    PubMed

    Nelesone, Tekaai; Durrheim, David N; Speare, Richard; Kiedrzynski, Tom; Melrose, Wayne D

    2006-01-01

    Successful communicable disease surveillance depends on effective bidirectional information flow between clinicians at the periphery and communicable disease control units at regional, national and global levels. Resource-poor countries often struggle to establish and maintain the crucial link with the periphery. A simple syndrome-based outbreak surveillance system initially developed and evaluated in Mpumalanga Province, South Africa was adapted for the Pacific island nation of Tuvalu. Eight syndromes were identified for surveillance: acute flaccid paralysis (poliomyelitis), profuse watery diarrhoea (cholera), diarrhoea outbreak, dysentery outbreak, febrile disease with abdominal symptoms and headache (typhoid), febrile disease with generalized non-blistering rash (measles), febrile disease with intense headache and/or neck stiffness with or without haemorrhagic rash (meningococcal meningitis), and outbreaks of other febrile diseases of unknown origin. A user-oriented manual, the Tuvalu Outbreak Manual (http://www.wepi.org/books/tom/), was developed to support introduction of the surveillance system. Nurses working in seven outer island clinics and the hospital outpatient department on the main island rapidly report suspected outbreaks and submit weekly zero-reports to the central communicable disease control unit. An evaluation of the system after 12 months indicated that the Outbreak Manual was regarded as very useful by clinic nurses, and there was early evidence of improved surveillance and response to the disease syndromes under surveillance. PMID:16398751

  19. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    SciTech Connect

    Anderson, S G; Barty, C P J; Betts, S M; Brown, W J; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Hartemann, F V; Kuba, J; LaSage, G P; Rosenzweig, J B; Slaughter, D R; Springer, P T; Tremaine, A M

    2003-07-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

  20. Intercellular Communication Amplifies Stressful Effects in High-Charge, High-Energy (HZE) Particle-Irradiated Human Cells

    PubMed Central

    AUTSAVAPROMPORN, Narongchai; DE TOLEDO, Sonia M.; BUONANNO, Manuela; JAY-GERIN, Jean-Paul; HARRIS, Andrew L.; AZZAM, Edouard I.

    2014-01-01

    Understanding the mechanisms that underlay the biological effects of particulate radiations is essential for space exploration and for radiotherapy. Here, we investigated the role of gap junction intercellular communication (GJIC) in modulating harmful effects induced in confluent cultures wherein most cells are traversed by one or more radiation tracks. We focused on the effect of radiation quality (linear energy transfer; LET) on junctional propagation of DNA damage and cell death among the irradiated cells. Confluent normal human fibroblasts were exposed to graded doses of 1 GeV protons (LET ~0.2 keV/μm) or 1 GeV/u iron ions (LET ~151 keV/μm) and were assayed for clonogenic survival and for micronucleus formation, a reflection of DNA damage, shortly after irradiation and following longer incubation periods. Iron ions were ~2.7 fold more effective than protons at killing 90% of the cells in the exposed cultures when assayed within 5–10 minutes after irradiation. When cells were held in the confluent state for several hours after irradiation, substantial repair of potentially lethal damage (PLDR), coupled with a reduction in micronucleus formation, occurred in cells exposed to protons, but not in those exposed to iron ions. In fact, such confluent holding after exposure to a similarly toxic dose of iron ions enhanced the induced toxic effect. However, following iron ion irradiation, inhibition of GJIC by 18-α-glycyrrhetinic acid eliminated the enhanced toxicity and reduced micronucleus formation to levels below those detected in cells assayed shortly after irradiation. The data show that low LET radiation induces strong PLDR within hours, but that high LET radiation with similar immediate toxicity does not induce PLDR and its toxicity increases with time following irradiation. The results also show that GJIC among irradiated cells amplifies stressful effects following exposure to high, but not LET radiation, and that GJIC has only minimal effect on cellular

  1. Laser-induced resonance states as dynamic suppressors of ionization in high-frequency short pulses

    SciTech Connect

    Barash, Danny; Orel, Ann E.; Baer, Roi

    2000-01-01

    An adiabatic-Floquet formalism is used to study the suppression of ionization in short laser pulses. In the high-frequency limit the adiabatic equations involve only the pulse envelope where transitions are purely ramp effects. For a short-ranged potential having a single-bound state we show that ionization suppression is caused by the appearance of a laser-induced resonance state, which is coupled by the pulse ramp to the ground state and acts to trap ionizing flux. (c) 1999 The American Physical Society.

  2. Short communication: evaluation of bovine milk residues from routine milk testing programs as DNA source for genotyping.

    PubMed

    Krappmann, K; Wurmser, C; Repsilber, D; Fries, R; Weikard, R; Kesting, U; Kühn, C

    2012-09-01

    Genome-wide association studies and genomic evaluation using a dense set of genetic markers both require a large number of genotyped individuals. Collection of the respective samples contributes substantially to the cost of the approach. In dairy cattle research, the use of residues from routine milk recording would be a cost-saving alternative to obtain samples for an appropriate number of individuals with specific phenotypes in a very short time. To assess the suitability of milk recording residues, we concurrently investigated milk residues obtained after standardized milk recording procedures and blood samples from 115 cows originating from 3 farms with different milking systems by genotyping 15 microsatellite markers. We found that 4% of the milk samples were possibly assigned to the wrong animal (i.e., conflicts) and that at least 27% of the milk residues were contaminated, as indicated by an extra allele not present in the blood sample. These additional alleles primarily originated from a sample with a higher somatic cell score that went through the milk sample analyzer in the milk laboratory before the target sample. Furthermore, additional allele carryover was observed across more than one sample, when the difference in somatic cell count between samples exceeded 100,000 cells/mL. Finally, in several samples, the extra allele could not be traced back to previous samples passing through the milk sample analyzer. One source of those contaminations might be sample collection on-farm due to milk traces from the previously milked cow in the hose. No correlation was found between the farm management and conflicts or contaminations. We conclude that residues from routine milk recording are not suitable for genomic evaluation or genome-wide association studies because of the high prevalence of contamination generated at several steps during the collection and processing of milk residual samples. PMID:22916950

  3. Anomalous high photoconductivity in short channel indium-zinc-oxide photo-transistors

    SciTech Connect

    Choi, Hyun-Sik; Jeon, Sanghun

    2015-01-05

    Upon light exposure, an indium-zinc-oxide (IZO) thin-film transistor (TFT) presents higher photoconductivity by several orders of magnitude at the negative gate bias region. Among various device geometrical factors, scaling down the channel length of the photo-transistor results in an anomalous increase in photoconductivity. To probe the origin of this high photoconductivity in short-channel device, we measured transient current, current–voltage, and capacitance–voltage characteristics of IZO–TFTs with various channel lengths and widths before and after illumination. Under the illumination, the equilibrium potential region which lies far from front interface exists only in short-channel devices, forming the un-depleted conducting back channel. This region plays an important role in carrier transport under the illumination, leading to high photoconductivity in short-channel devices. Photon exposure coupled with gate-modulated band bending for short-channel devices leads to the accumulation of V{sub o}{sup ++} at the front channel and screening negative gate bias, thereby generating high current flow in the un-depleted back-channel region.

  4. Anomalous high photoconductivity in short channel indium-zinc-oxide photo-transistors

    NASA Astrophysics Data System (ADS)

    Choi, Hyun-Sik; Jeon, Sanghun

    2015-01-01

    Upon light exposure, an indium-zinc-oxide (IZO) thin-film transistor (TFT) presents higher photoconductivity by several orders of magnitude at the negative gate bias region. Among various device geometrical factors, scaling down the channel length of the photo-transistor results in an anomalous increase in photoconductivity. To probe the origin of this high photoconductivity in short-channel device, we measured transient current, current-voltage, and capacitance-voltage characteristics of IZO-TFTs with various channel lengths and widths before and after illumination. Under the illumination, the equilibrium potential region which lies far from front interface exists only in short-channel devices, forming the un-depleted conducting back channel. This region plays an important role in carrier transport under the illumination, leading to high photoconductivity in short-channel devices. Photon exposure coupled with gate-modulated band bending for short-channel devices leads to the accumulation of Vo++ at the front channel and screening negative gate bias, thereby generating high current flow in the un-depleted back-channel region.

  5. Short communication: Modulation of the small intestinal microbial community composition over short-term or long-term administration with Lactobacillus plantarum ZDY2013.

    PubMed

    Xie, Qiong; Pan, Mingfang; Huang, Renhui; Tian, Ximei; Tao, Xueying; Shah, Nagendra P; Wei, Hua; Wan, Cuixiang

    2016-09-01

    The small intestinal (SI) microbiota has an essential role in the maintenance of human health. However, data about the indigenous bacteria in SI as affected by probiotics are limited. In our study, the short-term and long-term effects of a probiotic candidate, Lactobacillus plantarum ZDY2013, on the SI microbiota of C57BL/6J mice were investigated by the Illumina HiSeq (Novogene Bioinformatics Technology Co., Ltd., Tianjin, China) platform targeting the V4 region of the 16S rDNA. A total of 858,011 sequences in 15 samples were read. The α diversity analysis revealed that oral administration with L. plantarum ZDY2013 for 3 wk led to a significant increase in the richness and diversity of the SI bacterial community. Principal coordinate analysis and unweighted pair-group method with arithmetic means analysis showed a clear alteration in the SI microbiota composition after 3 wk of L. plantarum ZDY2013 treatment, although these changes were not found 6 wk after ceasing L. plantarum ZDY2013 administration. Species annotation showed that the dominant phyla in SI microbiota were Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia. Interestingly, operational taxonomic unit cluster analysis showed that administration with L. plantarum ZDY2013 for 3 wk significantly increased the abundance of Proteobacteria, but decreased that of Bacteroidetes. Linear discriminant analysis coupled with effect size identified 18 bacterial taxa (e.g., Ruminococcus spp. and Clostridium spp.) that overgrew in the SI microbiota of the mice administered with L. plantarum ZDY2013 for 3 wk, and most of them belonged to the phyla Bacteroidetes and Proteobacteria. However, only one bacterial taxon (e.g., Nocardioides spp.) was over-represented in the SI microbiota of mice 6 wk after L. plantarum ZDY2013 administration. Overall, this study shows that oral administration with probiotic results in an important but transient alteration in the microbiota of SI. PMID:27320669

  6. Application of advanced high speed turboprop technology to future civil short-haul transport aircraft design

    NASA Technical Reports Server (NTRS)

    Conlon, J. A.; Bowles, J. V.

    1978-01-01

    With an overall goal of defining the needs and requirements for short-haul transport aircraft research and development, the objective of this paper is to determine the performance and noise impact of short-haul transport aircraft designed with an advanced turboprop propulsion system. This propulsion system features high-speed propellers that have more blades and reduced diameters. Aircraft are designed for short and medium field lengths; mission block fuel and direct operating costs (DOC) are used as performance measures. The propeller diameter was optimized to minimize DOC. Two methods are employed to estimate the weight of the acoustic treatment needed to reduce interior noise to an acceptable level. Results show decreasing gross weight, block fuel, DOC, engine size, and optimum propfan diameter with increasing field length. The choice of acoustic treatment method has a significant effect on the aircraft design.

  7. An International Information Order? A Short Survey on the History and the Present State of a Challenging Concept. Communication Manual.

    ERIC Educational Resources Information Center

    Keune, Reinhard

    The issue of a world-wide information order is the focus of this paper, which outlines the history, status, perspective, and consequences of the NIICO (International Information and Communication Order) debate. The first section explains the concerns and events that led to a unanimously passed resolution by UNESCO calling for a new order for the…

  8. A Short Review of Information and Communication Technologies and Basic Education in LDCs--What Is Useful, What Is Sustainable?

    ERIC Educational Resources Information Center

    Grace, Jeremy; Kenny, Charles

    2003-01-01

    Information and communication technologies such as radio and television have long been used in education. The advent of the technology of the Internet has created pressure for Internet access in primary and secondary schools across the world. This paper reviews some of the available evidence on the impact and cost of such technologies in…

  9. A low-complexity and high performance concatenated coding scheme for high-speed satellite communications

    NASA Technical Reports Server (NTRS)

    Lin, Shu; Rhee, Dojun; Rajpal, Sandeep

    1993-01-01

    This report presents a low-complexity and high performance concatenated coding scheme for high-speed satellite communications. In this proposed scheme, the NASA Standard Reed-Solomon (RS) code over GF(2(exp 8) is used as the outer code and the second-order Reed-Muller (RM) code of Hamming distance 8 is used as the inner code. The RM inner code has a very simple trellis structure and is decoded with the soft-decision Viterbi decoding algorithm. It is shown that the proposed concatenated coding scheme achieves an error performance which is comparable to that of the NASA TDRS concatenated coding scheme in which the NASA Standard rate-1/2 convolutional code of constraint length 7 and d sub free = 10 is used as the inner code. However, the proposed RM inner code has much smaller decoding complexity, less decoding delay, and much higher decoding speed. Consequently, the proposed concatenated coding scheme is suitable for reliable high-speed satellite communications, and it may be considered as an alternate coding scheme for the NASA TDRS system.

  10. A low-complexity and high performance concatenated coding scheme for high-speed satellite communications

    NASA Astrophysics Data System (ADS)

    Lin, Shu; Rhee, Dojun; Rajpal, Sandeep

    1993-02-01

    This report presents a low-complexity and high performance concatenated coding scheme for high-speed satellite communications. In this proposed scheme, the NASA Standard Reed-Solomon (RS) code over GF(2(exp 8) is used as the outer code and the second-order Reed-Muller (RM) code of Hamming distance 8 is used as the inner code. The RM inner code has a very simple trellis structure and is decoded with the soft-decision Viterbi decoding algorithm. It is shown that the proposed concatenated coding scheme achieves an error performance which is comparable to that of the NASA TDRS concatenated coding scheme in which the NASA Standard rate-1/2 convolutional code of constraint length 7 and d sub free = 10 is used as the inner code. However, the proposed RM inner code has much smaller decoding complexity, less decoding delay, and much higher decoding speed. Consequently, the proposed concatenated coding scheme is suitable for reliable high-speed satellite communications, and it may be considered as an alternate coding scheme for the NASA TDRS system.

  11. Space Link Extension (SLE) Emulation for High-Throughput Network Communication

    NASA Technical Reports Server (NTRS)

    Murawski, Robert W.; Tchorowski, Nicole; Golden, Bert

    2014-01-01

    As the data rate requirements for space communications increases, significant stress is placed not only on the wireless satellite communication links, but also on the ground networks which forward data from end-users to remote ground stations. These wide area network (WAN) connections add delay and jitter to the end-to-end satellite communication link, effects which can have significant impacts on the wireless communication link. It is imperative that any ground communication protocol can react to these effects such that the ground network does not become a bottleneck in the communication path to the satellite. In this paper, we present our SCENIC Emulation Lab testbed which was developed to test the CCSDS SLE protocol implementations proposed for use on future NASA communication networks. Our results show that in the presence of realistic levels of network delay, high-throughput SLE communication links can experience significant data rate throttling. Based on our observations, we present some insight into why this data throttling happens, and trace the probable issue back to non-optimal blocking communication which is sup-ported by the CCSDS SLE API recommended practices. These issues were presented as well to the SLE implementation developers which, based on our reports, developed a new release for SLE which we show fixes the SLE blocking issue and greatly improves the protocol throughput. In this paper, we also discuss future developments for our end-to-end emulation lab and how these improvements can be used to develop and test future space communication technologies.

  12. Transformation of short-periodic high-inclination orbits of circumsolar submillimeter dust

    SciTech Connect

    Bazei, A.A.; Kramer, E.N.

    1995-11-01

    Disintegration of short-periodic comets is one of the sources of cosmic dust in the Solar System. Initially dust particles move approximately in the orbits of parent comets, in particular, in high-inclination orbits. In a few million years, some of these particles (the smallest ones) go over to the short-periodic, high-inclination orbits due to the Poynting-Robertson effect. The numerical integration of the equations of motion at this stage of evolution gives rise to somewhat surprising results. For example, when integrating the equations of motion as far back as 6000 years from the time of meteor observation, the real meteor particle gains the perihelion distance smaller than the solar radius (!). Our calculations show that the time of falling onto the Sun is shorter for a article moving in a high-inclination orbit. This is due to the superposition of gravitational perturbation and radiation effects.

  13. Using Mobile Communication Technology in High School Education: Motivation, Pressure, and Learning Performance

    ERIC Educational Resources Information Center

    Rau, Pei-Luen Patrick; Gao, Qin; Wu, Li-Mei

    2008-01-01

    Motivation and pressure are considered two factors impacting vocational senior high school student learning. New communication technology, especially mobile communication technology, is supposed to be effective in encouraging interaction between the student and the instructor and improving learning efficiency. Social presence and information…

  14. Measuring University Students' Perceived Self-Efficacy in Science Communication in Middle and High Schools

    ERIC Educational Resources Information Center

    Chi, Shaohui; Liu, Xiufeng; Gardella, Joseph A.

    2016-01-01

    Service learning typically involves university students in teaching and learning activities for middle and high school students, however, measurement of university students' self-efficacy in science communication is still lacking. In this study, an instrument to measure university students' perceived self-efficacy in communicating science to…

  15. Whole-genome sequencing and assembly with high-throughput, short-read technologies.

    PubMed

    Sundquist, Andreas; Ronaghi, Mostafa; Tang, Haixu; Pevzner, Pavel; Batzoglou, Serafim

    2007-01-01

    While recently developed short-read sequencing technologies may dramatically reduce the sequencing cost and eventually achieve the $1000 goal for re-sequencing, their limitations prevent the de novo sequencing of eukaryotic genomes with the standard shotgun sequencing protocol. We present SHRAP (SHort Read Assembly Protocol), a sequencing protocol and assembly methodology that utilizes high-throughput short-read technologies. We describe a variation on hierarchical sequencing with two crucial differences: (1) we select a clone library from the genome randomly rather than as a tiling path and (2) we sample clones from the genome at high coverage and reads from the clones at low coverage. We assume that 200 bp read lengths with a 1% error rate and inexpensive random fragment cloning on whole mammalian genomes is feasible. Our assembly methodology is based on first ordering the clones and subsequently performing read assembly in three stages: (1) local assemblies of regions significantly smaller than a clone size, (2) clone-sized assemblies of the results of stage 1, and (3) chromosome-sized assemblies. By aggressively localizing the assembly problem during the first stage, our method succeeds in assembling short, unpaired reads sampled from repetitive genomes. We tested our assembler using simulated reads from D. melanogaster and human chromosomes 1, 11, and 21, and produced assemblies with large sets of contiguous sequence and a misassembly rate comparable to other draft assemblies. Tested on D. melanogaster and the entire human genome, our clone-ordering method produces accurate maps, thereby localizing fragment assembly and enabling the parallelization of the subsequent steps of our pipeline. Thus, we have demonstrated that truly inexpensive de novo sequencing of mammalian genomes will soon be possible with high-throughput, short-read technologies using our methodology. PMID:17534434

  16. Photosynthetic and Biochemical Changes in Response to Short Interval High ``g'' Exposure in Wheat

    NASA Astrophysics Data System (ADS)

    Dixit, Jyotsana; Vidyasagar, Pandit; Jagtap, Sagar; Kamble, Shailendra

    We have investigated the effect of short interval post imbibition high “g” exposure on wheat seeds (Triticum aestivum var.Lok-1) by evaluating the photosynthetic performance, chlorophyll “a” fluorescence biochemical indices and antioxidant response. Imbibed wheat seeds were exposed to high “g” ranging from 500 g to 2500 g for 10 min, allowed to germinate and grown for 5 days under normal gravity i.e. 1 g. Chlorophyll “a” fluorescence transient was examined in wheat seedling raised from hyper gravity treated seeds. Fv/Fm, PI, Fv/Fo decreased in high “g” treated seeds compared to control. Photosynthetic performance indices such as Transpiration rate, Stomatal conductance, Net photosynthetic rate, Intracellular CO2 concentration, Intrinsic water use efficiency also declined in wheat seedlings raised from High “g” treated seeds suggesting that high g reduces efficiency of photosynthesis in wheat seedlings. Results of Biochemical analysis showed reduced alpha- amylase activity in wheat seeds subjected to high “g” ranging from 500 g to 2500 g in a magnitude dependent manner. Decline in enzyme activity was positively correlated with higher starch content and lower reducing sugars in high “g” exposed wheat seeds. This possibly explains the reduced percent germination and growth in response to high “g”. Antioxidant enzyme activity (CAT and POX) significantly increased as a result of hypergravity exposure In conclusion, short interval high “g” exposure results in reduced growth and photosynthetic activity in wheat seedlings.

  17. Path loss modeling and performance trade-off study for short-range non-line-of-sight ultraviolet communications.

    PubMed

    Chen, Gang; Xu, Zhengyuan; Ding, Haipeng; Sadler, Brian

    2009-03-01

    We consider outdoor non-line-of-sight deep ultraviolet (UV) solar blind communications at ranges up to 100 m, with different transmitter and receiver geometries. We propose an empirical channel path loss model, and fit the model based on extensive measurements. We observe range-dependent power decay with a power exponent that varies from 0.4 to 2.4 with varying geometry. We compare with the single scattering model, and show that the single scattering assumption leads to a model that is not accurate for small apex angles. Our model is then used to study fundamental communication system performance trade-offs among transmitted optical power, range, link geometry, data rate, and bit error rate. Both weak and strong solar background radiation scenarios are considered to bound detection performance. These results provide guidelines to system design. PMID:19259234

  18. Prescriptions of dialysate potassium concentration during short daily or long nocturnal (high dose) hemodialysis.

    PubMed

    Leypoldt, John K; Agar, Baris U; Bernardo, Angelito A; Culleton, Bruce F

    2016-04-01

    The prescription of dialysate potassium concentration during short daily and long nocturnal (high dose) hemodialysis (HD) is challenging due to limited clinical experience with such modalities. The aim here is to propose a quantitative approach for prescribing dialysate potassium concentrations during high-dose HD. Potassium kinetic parameters based on a pseudo one-compartment model from 547 patients participating in the HEMO Study were used for prediction purposes in this study. Patients were categorized based on the prescribed dialysate potassium concentration during thrice weekly HD as 1K (mean of 1.02 mEq/L, N = 60), 2K (2.01 mEq/L, N = 437), or 3K (3.01 mEq/L, N = 50). Dialysate potassium concentrations were then predicted for each patient during short daily and long nocturnal HD based on a pseudo one-compartment model to maintain the identical weekly dialytic potassium removal and predialysis serum potassium concentration as during thrice weekly HD. Predicted prescribed dialysate potassium concentrations for short daily HD were 0.18-0.45 mEq/L higher than during thrice weekly HD but were approximately 4 (3.72-4.26) mEq/L for all patients during long nocturnal HD. The intradialytic decrease in serum potassium concentration was predicted to be reduced by more than one-half during short daily HD and by approximately three-quarters during long nocturnal HD of that during thrice weekly HD. Prescribed dialysate potassium concentration during high-dose HD modalities can be quantitatively predicted using a pseudo one-compartment kinetic model. High-dose HD modalities may improve clinical outcomes by reducing intradialytic decreases in serum potassium. PMID:26179136

  19. Measurement of high-birefringent spun fiber parameters using short-length fiber Bragg gratings.

    PubMed

    Vasiliev, S A; Przhiyalkovsky, Ya V; Gnusin, P I; Medvedkov, O I; Dianov, E M

    2016-05-30

    Spectral polarization characteristics of short-length fiber Bragg gratings UV-written in a highly-birefringent spun-fiber have been investigated. Based on the analysis of the characteristics the technique for measuring the built-in linear phase birefringence as well as the spin period in this fiber type has been suggested. In this method the birefringence dispersion is excluded and therefore the built-in linear phase birefringence can be measured with an improved accuracy. PMID:27410060

  20. Short-term optical variability of high-redshift quasi-stellar objects

    NASA Astrophysics Data System (ADS)

    Bachev, R.; Strigachev, A.; Semkov, E.

    2005-04-01

    In this paper we present the results of a search for short-term variability in the optical band of selected high-luminosity, high-redshift radio-quiet quasars. Each quasar has been monitored typically for 2-4 h with a time resolution of 2-5 min and a photometric accuracy of about 0.01-0.02 mag. As a result of the significant redshift (z > 2), the covered wavelength range falls into the ultraviolet region (typically 1500-2500 Å). We have found no statistical evidence for any continuum variations larger than 0.01-0.02 mag for any of the monitored objects. Our results suggest that the presence of a short-term variability in radio-quiet quasars is unlikely even in the ultraviolet region, contrary to reports by other authors. This conclusion holds true at least for high-luminosity (large black hole mass and accretion rate?) objects. The results are consistent with the idea that significant short-term (less than 1 h) variations in active galactic nuclei, where observed, should be attributed primarily to processes in a relativistic jet.

  1. Characteristics of High Energy Ka and Bremsstrahlung Sources Generated by Short Pulse Petawatt Lasers

    SciTech Connect

    Park, H; Izumi, N; Key, M H; Koch, J A; Landen, O L; Patel, P K; Phillips, T W; Zhang, B B

    2004-04-13

    We have measured the characteristics of high energy K{alpha} sources created with the Vulcan Petawatt laser at RAL and the JanUSP laser at LLNL. High energy x-ray backlighters will be essential for radiographing High-Energy-Density Experimental Science (HEDES) targets for NIF projects especially to probe implosions and high areal density planar samples. Hard K{alpha} x-ray photons are created through relativistic electron plasma interactions in the target material after irradiation by short pulse high intensity lasers. For our Vulcan experiment, we employed a CsI scintillator/CCD camera for imaging and a CCD camera for single photon counting. We measured the Ag K{alpha} source (22 keV) size using a pinhole array and the K{alpha} flux using a single photon counting method. We also radiographed a high Z target using the high energy broadband x-rays generated from these short pulse lasers. This paper will present results from these experiments.

  2. Short communication. The role of animal-sourced insulin in the treatment of type 1 diabetes and its availability.

    PubMed

    Klein, A V; Taylor, E; Legaré, C; Vu, D; Griffiths, E

    2014-07-01

    As a result of a number of factors, the treatment of insulin-dependent diabetes has moved away from using insulin of beef or pork origin to using recombinant (biosynthetic) insulin preparations. However, some people with type 1 diabetes can manage their diabetes better using animal-sourced insulin. Despite dwindling options and decreased production, animal-sourced insulin (and pork insulin in particular) is still available on the Canadian market. This communication describes the actions taken by Health Canada with respect to the availability of animal insulin. PMID:24991780

  3. Parallel PIC Simulations of Short-Pulse High Intensity Laser Plasma Interactions.

    NASA Astrophysics Data System (ADS)

    Lasinski, B. F.; Still, C. H.; Langdon, A. B.

    2001-10-01

    We extend our previous simulations of high intensity short pulse laser plasma interactions footnote B. F. Lasinski, A. B. Langdon, S. P. Hatchett, M. H. Key, and M. Tabak, Phys. Plasmas 6, 2041 (1999); S. C. Wilks and W. L. Kruer, IEEE Journal of Quantum Electronics 11, 1954 (1997). to 3D and to much larger systems in 2D using our new, modern, 3D, electromagnetic, fully relativistic, massively parallel PIC code. We study the generation of hot electrons and energetic ions and the associated complex phenomena. Laser light filamentation and the formation of high static magnetic fields are described.

  4. Acute ischaemic stroke during short-term travel to high altitude.

    PubMed

    Chan, T; Wong, Winnie W Y; Chan, Jonathan K C; Ma, Johnny K F; Mak, Henry K F

    2012-02-01

    This is a case report of a young healthy adult who had acute cerebral infarcts after a short-term visit to high-altitude area. He developed acute onset of right-sided limb weakness and right hemianopia a few hours after arrival at an altitude of 3600 m by train. He was initially treated for high-altitude cerebral oedema but later computed tomography and magnetic resonance imaging confirmed ischaemic infarcts in the medial left occipital lobe and left thalamus. Subsequent investigations, including laboratory tests and imaging including an echocardiogram, revealed no culpable predisposing factors. PMID:22302915

  5. Generating high-power short terahertz electromagnetic pulses with a multifoil radiator.

    PubMed

    Vinokurov, Nikolay A; Jeong, Young Uk

    2013-02-01

    We describe a multifoil cone radiator capable of generating high-field short terahertz pulses using short electron bunches. Round flat conducting foil plates with successively decreasing radii are stacked, forming a truncated cone with the z axis. The gaps between the foil plates are equal and filled with some dielectric (or vacuum). A short relativistic electron bunch propagates along the z axis. At sufficiently high particle energy, the energy losses and multiple scattering do not change the bunch shape significantly. When passing by each gap between the foil plates, the electron bunch emits some energy into the gap. Then, the radiation pulses propagate radially outward. For transverse electromagnetic waves with a longitudinal (along the z axis) electric field and an azimuthal magnetic field, there is no dispersion in these radial lines; therefore, the radiation pulses conserve their shapes (time dependence). At the outer surface of the cone, we have synchronous circular radiators. Their radiation field forms a conical wave. Ultrashort terahertz pulses with gigawatt-level peak power can be generated with this device. PMID:23432259

  6. High-speed highly temperature stable 980 nm VCSELs operating at 25 Gb/s at up to 85 °C for short reach optical interconnects

    NASA Astrophysics Data System (ADS)

    Mutig, Alex; Lott, James A.; Blokhin, Sergey A.; Moser, Philip; Wolf, Philip; Hofmann, Werner; Nadtochiy, Alexey M.; Bimberg, Dieter

    2011-03-01

    The progressive penetration of optical communication links into traditional copper interconnect markets greatly expands the applications of vertical cavity surface emitting lasers (VCSELs) for the next-generation of board-to-board, moduleto- module, chip-to-chip, and on-chip optical interconnects. Stability of the VCSEL parameters at high temperatures is indispensable for such applications, since these lasers typically reside directly on or near integrated circuit chips. Here we present 980 nm oxide-confined VCSELs operating error-free at bit rates up to 25 Gbit/s at temperatures as high as 85 °C without adjustment of the drive current and peak-to-peak modulation voltage. The driver design is therefore simplified and the power consumption of the driver electronics is lowered, reducing the production and operational costs. Small and large signal modulation experiments at various temperatures from 20 up to 85 °C for lasers with different oxide aperture diameters are presented in order to analyze the physical processes controlling the performance of the VCSELs. Temperature insensitive maximum -3 dB bandwidths of around 13-15 GHz for VCSELs with aperture diameters of 10 μm and corresponding parasitic cut-off frequencies exceeding 22 GHz are observed. Presented results demonstrate the suitability of our VCSELs for practical high speed and high temperature stable short-reach optical links.

  7. VERY HIGH-SPEED DRILL STRING COMMUNICATIONS NETWORK

    SciTech Connect

    David S. Pixton

    2002-11-01

    Testing of a high-speed digital data transmission system for drill pipe is described. Passive transmission of digital data through 1000 ft of telemetry drill pipe has been successfully achieved. Data rates of up to 2 Mbit/sec have been tested through the 1000 ft system with very low occurrence of data errors: required error correction effort is very low or nonexistent. Further design modifications have been made to improve manufacturability and high pressure robustness of the transmission line components. Failure mechanisms of previous designs at high pressure and high temperature are described. Present design limitations include high temperature application.

  8. Neonatal overfeeding attenuates acute central pro-inflammatory effects of short-term high fat diet

    PubMed Central

    Cai, Guohui; Dinan, Tara; Barwood, Joanne M.; De Luca, Simone N.; Soch, Alita; Ziko, Ilvana; Chan, Stanley M. H.; Zeng, Xiao-Yi; Li, Songpei; Molero, Juan; Spencer, Sarah J.

    2015-01-01

    Neonatal obesity predisposes individuals to obesity throughout life. In rats, neonatal overfeeding also leads to early accelerated weight gain that persists into adulthood. The phenotype is associated with dysfunction in a number of systems including paraventricular nucleus of the hypothalamus (PVN) responses to psychological and immune stressors. However, in many cases weight gain in neonatally overfed rats stabilizes in early adulthood so the animal does not become more obese as it ages. Here we examined if neonatal overfeeding by suckling rats in small litters predisposes them to exacerbated metabolic and central inflammatory disturbances if they are also given a high fat diet in later life. In adulthood we gave the rats normal chow, 3 days, or 3 weeks high fat diet (45% kcal from fat) and measured peripheral indices of metabolic disturbance. We also investigated hypothalamic microglial changes, as an index of central inflammation, as well as PVN responses to lipopolysaccharide (LPS). Surprisingly, neonatal overfeeding did not predispose rats to the metabolic effects of a high fat diet. Weight changes and glucose metabolism were unaffected by the early life experience. However, short term (3 day) high fat diet was associated with more microglia in the hypothalamus and a markedly exacerbated PVN response to LPS in control rats; effects not seen in the neonatally overfed. Our findings indicate neonatally overfed animals are not more susceptible to the adverse metabolic effects of a short-term high fat diet but may be less able to respond to the central effects. PMID:25628527

  9. High Capacity Communications From Martian Distances. Part 1; Spacecraft Link Design Analysis

    NASA Technical Reports Server (NTRS)

    Vyas, Hemali N.; Schuchman, Leonard; Orr, Richard; Williams, Wallace Dan; Collins, Michael; Noreen, Gary

    2006-01-01

    High capacity space communications has been a desire for Human Exploration and Science missions. Current Mars missions operate at data rates of 120 kbps for telemetry downlink and it is desirable to study high rate communication links in the range of 100 Mbps to 1 Gbps data rates from Martian distances. This paper will present some assumed scenarios along with link design assumptions and link analysis for high capacity communications from Mars. The paper will focus on RF subsystems namely antenna and power for the downlink communication from a relay orbiter at Mars. The relay orbiter will communicate with the low orbit spacecrafts at Mars or any Martian surface elements such as robots, and relay the data back to the ground networks on Earth. The study will dive into the spacecraft downlink system design and communication link analysis between the relay orbiter and ground network on Earth for data rates ranging from 100 Mbps to 1 Gbps based on the assumed scenarios and link assumptions. With high rate links at larger distances, there will be a significant impact on the antenna and power requirements and the link design will make an attempt to minimize the mass of the RF subsystem on the spacecraft. The results of this study will be presented for three data rates 1 Gbps, 500 Mbps and 100 Mbps at maximum Mars to Earth distance of 2.67AU. The design will use a Ka-band downlink with 90% link availability, along with various ground network G/T assumptions and possible bandwidth efficient modulations. The paper will conclude with what types of high rate communication links are feasible from Martian distances and also identify a range of requirements for antenna and power technologies for these high capacity communications from Mars.

  10. Space Link Extension (SLE) Emulation for High-Throughput Network Communication

    NASA Technical Reports Server (NTRS)

    Murawski, Robert; Tchorowski, Nicole; Golden, Bert

    2014-01-01

    As the data rate requirements for space communications increases, signicant stressis placed not only on the wireless satellite communication links, but also on the groundnetworks which forward data from end-users to remote ground stations. These wide areanetwork (WAN) connections add delay and jitter to the end-to-end satellite communicationlink, eects which can have signicant impacts on the wireless communication link. It isimperative that any ground communication protocol can react to these eects such that theground network does not become a bottleneck in the communication path to the satellite.In this paper, we present our SCENIC Emulation Lab testbed which was developed to testthe CCSDS SLE protocol implementations proposed for use on future NASA communica-tion networks. Our results show that in the presence of realistic levels of network delay,high-throughput SLE communication links can experience signicant data rate throttling.Based on our observations, we present some insight into why this data throttling happens,and trace the probable issue back to non-optimal blocking communication which is sup-ported by the CCSDS SLE API recommended practices. These issues were presented aswell to the SLE implementation developers which, based on our reports, developed a newrelease for SLE which we show xes the SLE blocking issue and greatly improves the pro-tocol throughput. In this paper, we also discuss future developments for our end-to-endemulation lab and how these improvements can be used to develop and test future spacecommunication technologies.

  11. Physical characteristics of geosynchronous high power communications satellites

    SciTech Connect

    Drackett, T.M.

    1995-12-31

    With the advent of the Information Superhighway, many organizations have been spurred into re-examining current spacecraft architectures to determine how the significantly higher communications capacities of the future will be accommodated. Opinion is divided on many issues in this arena, and none more so than the discussion that revolves around whether several large satellites in Geosynchronous Orbit (GEO) offer a better all-round service to the user community than a fleet of small satellites in Low Earth Orbit (LEO). Although this paper does not attempt to debate this particular issue, a clear finding of the work carried out by the author and others, was that considerable growth potential exists by simply increasing the physical size and capacity of conventional geosynchronous satellites while causing a minimal impact on existing ground systems and infrastructures. The work described here forms part of a power systems study carried out by Lockheed Martin Astro Space (Astro), and funded by the Department of Energy (DOE), to investigate how photovoltaic and reactor based power technology can be applied to spacecraft with payloads in the 20 kW to 100 kW range. The scope of this paper is to address how the payload type, power source technology and launch vehicle selection influence the physical characteristics of satellites with payloads of this magnitude.

  12. RAPID COMMUNICATION: High performance superconducting wire in high applied magnetic fields via nanoscale defect engineering

    NASA Astrophysics Data System (ADS)

    Wee, Sung Hun; Goyal, Amit; Zuev, Yuri L.; Cantoni, Claudia

    2008-09-01

    High temperature superconducting (HTS) wires capable of carrying large critical currents with low dissipation levels in high applied magnetic fields are needed for a wide range of applications. In particular, for electric power applications involving rotating machinery, such as large-scale motors and generators, a high critical current, Ic, and a high engineering critical current density, JE, in applied magnetic fields in the range of 3-5 Tesla (T) at 65 K are required. In addition, exceeding the minimum performance requirements needed for these applications results in a lower fabrication cost, which is regarded as crucial to realize or enable many large-scale bulk applications of HTS materials. Here we report the fabrication of short segments of a potential superconducting wire comprised of a 4 µm thick YBa2Cu3O7-δ (YBCO) layer on a biaxially textured substrate with a 50% higher Ic and JE than the highest values reported previously. The YBCO film contained columns of self-assembled nanodots of BaZrO3 (BZO) roughly oriented along the c-axis of YBCO. Although the YBCO film was grown at a high deposition rate, three-dimensional self-assembly of the insulating BZO nanodots still occurred. For all magnetic field orientations, minimum Ic and JE at 65 K, 3 T for the wire were 353 A cm-1 and 65.4 kA cm-2, respectively.

  13. Analytical performance study of solar blind non-line-of-sight ultraviolet short-range communication links.

    PubMed

    Xu, Zhengyuan; Ding, Haipeng; Sadler, Brian M; Chen, Gang

    2008-08-15

    Motivated by recent advances in solid-state incoherent ultraviolet sources and solar blind detectors, we study communication link performance over a range of less than 1 km with a bit error rate (BER) below 10(-3) in solar blind non-line-of-sight situation. The widely adopted yet complex single scattering channel model is significantly simplified by means of a closed-form expression for tractable analysis. Path loss is given as a function of transceiver geometry as well as atmospheric scattering and attenuation and is compared with experimental data for model validation. The BER performance of a shot-noise-limited receiver under this channel model is demonstrated. PMID:18709113

  14. High reliability K-band electron tubes for satellite communication

    NASA Astrophysics Data System (ADS)

    Hirata, H.; Kawashima, F.

    1980-09-01

    Design methods and performance results for long life and high reliability satellite TWT and high power klystron with wide band tunability are presented. Emphasis is placed on problems observed during early operation. Tuning instability is solved by analyzing possible spurious modes at the tuner and by designing a structure to suppress spurious modes. A feedback mechanism is also discussed to handle instability in preset-tuning. Cathode design, electron beam focusing, and electron gun structure at a high frequency band are examined.

  15. Lifetime measurements of high-lying short lived states in {sup 69}As

    SciTech Connect

    Matejska-Minda, M.; Bednarczyk, P.; Fornal, B.; Ciemala, M.; Kmiecik, M.; Krzysiek, M.; Maj, A.; Meczynski, W.; Myalski, S.; Styczen, J.; Zieblinski, M.; Angelis, G. de; Huyuk, T.; Michelagnoli, C.; Sahin, E.; Aydin, S.; Farnea, E.; Menegazzo, R.; Recchia, F.; Ur, C. A.; and others

    2012-10-20

    Lifetimes of high-spin states in {sup 69}As have been measured using Doppler shift attenuation technique with the GASP and RFD setup. The determined transition probabilities indicate large deformation associated with some rotational bands in this nucleus.

  16. Lifetime measurements of high-lying short lived states in 69As

    NASA Astrophysics Data System (ADS)

    Matejska-Minda, M.; Bednarczyk, P.; Fornal, B.; Ciemała, M.; Kmiecik, M.; Krzysiek, M.; Maj, A.; Meczyński, W.; Myalski, S.; Styczén, J.; Ziebliński, M.; de Angelis, G.; Huyuk, T.; Michelagnoli, C.; Sahin, E.; Aydin, S.; Farnea, E.; Menegazzo, R.; Recchia, F.; Ur, C. A.; Brambilla, S.; Leoni, S.; Montanari, D.; Jaworski, G.; Palacz, M.; Wadsworth, R.

    2012-10-01

    Lifetimes of high-spin states in 69As have been measured using Doppler shift attenuation technique with the GASP and RFD setup. The determined transition probabilities indicate large deformation associated with some rotational bands in this nucleus.

  17. Probing the Virus Host Interaction in High Containment: An Approach Using Pooled Short Hairpin RNA

    PubMed Central

    Filone, Claire Marie; Dower, Ken; Cowley, Glenn S.; Hensley, Lisa E.

    2015-01-01

    Abstract The study of viruses in high containment offers unique challenges for technology-intense approaches. These approaches include high-throughput screening for small-molecule antivirals and genetic perturbation-based screens for host factors required for viral replication. Here, we describe the use of whole-genome scale pooled short hairpin RNA (shRNA) libraries to screen for host factors necessary for viral infection at BSL2, and the transition of this technique into the BSL4 environment. Pooled screening provides a unique way to circumvent many of the technological challenges associated with other high-throughput screening approaches in high containment. Our pooled screening approach identified host factors involved in the replication of orthopoxviruses (Vaccinia and Monkeypox) and filoviruses (Ebola and Marburg) under conditions that enable straightforward screen-to-follow-up approaches. PMID:25646658

  18. Short communication: Test for nonpregnancy in dairy cows based on plasma progesterone concentrations before and after timed artificial insemination.

    PubMed

    Wilsdorf, L J; Keisler, D H; Poock, S E; Lamberson, W R; Escalante, R C; Lucy, M C

    2016-07-01

    Timed artificial insemination (AI) programs have increased reproductive efficiency in dairy herds. A low timed AI pregnancy per AI is partially explained by cows that fail to respond optimally to the series of treatments that are designed to synchronize ovulation for AI. We hypothesized that testing cows for plasma progesterone concentrations during a timed AI protocol could be used as an early diagnostic test for nonpregnancy. Lactating Holstein cows (n=160) in 2 confinement-style dairies were used. Cows were treated with Presynch Ovsynch 56 for timed AI. Concentrations of progesterone in plasma were measured at -3, 0, 7, and 25 d relative to timed AI. Progesterone data were analyzed and receiver operating characteristic curves were generated by using logistic regression. The area under the receiver operating curves for a progesterone test for nonpregnancy on d -3 (PGF2α), 0 (AI), 7, and 25 d relative to timed AI were 0.68, 0.52, 0.55, and 0.89, respectively. The cutpoints and sensitivity (respectively) for the progesterone test were 0.51ng/mL (lower=nonpregnant) and 28.2% for the day of PGF2α, 0.43ng/mL (greater=nonpregnant) and 17.9% for the day of AI, 1.82ng/mL (lower=nonpregnant) and 23.1% for 7 d after AI, and 2.67ng/mL (lower=nonpregnant) and 76.0% for 25 d after AI. The false positive rate was less than 5% for all tests. Analysis of a second data set from a published study gave approximately the same cutpoints and sensitivity. When both studies were combined, approximately 20% of nonpregnant cows could be identified with a single test that was done before or shortly after AI with a false positive rate of less than 5%. When 2 and 3 tests were applied sequentially, the sensitivity for identifying nonpregnant cows increased from 38.4 to 50.5%. The pregnancy per AI for those cows that met the established progesterone criteria was approximately 3 to 4 times greater than those that failed to meet the criteria. The conclusions were that cows destined to be

  19. Short-course Astronomical Research Seminars for High School and College Students

    NASA Astrophysics Data System (ADS)

    Johnson, Jolyon

    2011-05-01

    Since 2008, I have helped lead several short-course astronomical research seminars with Russell M. Genet. These seminars have ranged from semester-long courses at Cuesta College in San Luis Obispo, California to long weekends at the University of Oregon's Pine Mountain Observatory. Each seminar is led by an experienced observer or group of observers who guide high school and college students through the scientific process from observations to publication. The students (anywhere from half a dozen to twenty in number) participate in and contribute to every step. Being a coauthor on one or more research papers offers students an advantage on college and scholarship applications. Similarly, graduate schools often prefer students with research experience. Many topics of research are appropriate for these short-courses including variable star, exoplanet, and asteroid photometry. However, the most successful topic has been visual double stars because the observations required are straitforward and the equipment is relatively inexpensive. The Journal of Double Star Observations is also welcoming of student research and provides swift publication. A detailed description of the short-course seminars can be found in the recent Collins Foundation Press volume titled Small Telescopes and Astronomical Research.

  20. High Energy K(alpha) Radiography Using High-intensity, Short-pulse Lasers

    SciTech Connect

    Park, H; Izumi, N; Key, M H; King, J A; Koch, J A; Landen, O L; Patel, P K; Price, D F; Remington, B A; Robey, H F; Snavely, R A; Tabak, M; Town, R J; Wickersham, J E; Stoeckl, C; Storm, M; Theobald, W; Chambers, D M; Eagelton, R; Goldsack, T; Clarke, R J; Heathcote, R; Giraldez, E; Nikroo, A; Steinman, D A; Stephens, R B; Zhang, B B

    2005-11-16

    We have performed experiments using Callisto, the Vulcan 100 TW and the Vulcan Petawatt high intensity lasers to understand the characteristics of high energy, K{alpha} x-ray sources and to implement workable radiography solutions at 20-100 keV. Our measurements show that the K{alpha} size from a simple foil target is larger than 60 {micro}m, far larger than the experiment resolution requirement. The total K{alpha} yield is independent of target thicknesses verifying that refluxing plays a major role in photon generation. Smaller radiating volumes emit brighter K{alpha} radiation. 1-D radiography experiments using small-edge-on foils resolved 10 {micro}m features with high contrast. We tested a variety of small volume 2-D point sources such as cones, wires, and embedded wires, measuring photon yields and comparing our measurements with predictions from hybrid-PIC LSP simulations. In addition to high-energy, high-resolution backlighters, future experiments will also need imaging detectors and diagnostic tools that are workable in the 20-100 keV energy range. An initial look at some of these detector issues is also presented.

  1. Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications.

    PubMed

    Huang, Xianjun; Leng, Ting; Zhu, Mengjian; Zhang, Xiao; Chen, JiaCing; Chang, KuoHsin; Aqeeli, Mohammed; Geim, Andre K; Novoselov, Kostya S; Hu, Zhirun

    2015-01-01

    In this paper, we report highly conductive, highly flexible, light weight and low cost printed graphene for wireless wearable communications applications. As a proof of concept, printed graphene enabled transmission lines and antennas on paper substrates were designed, fabricated and characterized. To explore its potentials in wearable communications applications, mechanically flexible transmission lines and antennas under various bended cases were experimentally studied. The measurement results demonstrate that the printed graphene can be used for RF signal transmitting, radiating and receiving, which represents some of the essential functionalities of RF signal processing in wireless wearable communications systems. Furthermore, the printed graphene can be processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers and textiles. This work brings a step closer to the prospect to implement graphene enabled low cost and environmentally friendly wireless wearable communications systems in the near future. PMID:26673395

  2. Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications

    NASA Astrophysics Data System (ADS)

    Huang, Xianjun; Leng, Ting; Zhu, Mengjian; Zhang, Xiao; Chen, Jiacing; Chang, Kuohsin; Aqeeli, Mohammed; Geim, Andre K.; Novoselov, Kostya S.; Hu, Zhirun

    2015-12-01

    In this paper, we report highly conductive, highly flexible, light weight and low cost printed graphene for wireless wearable communications applications. As a proof of concept, printed graphene enabled transmission lines and antennas on paper substrates were designed, fabricated and characterized. To explore its potentials in wearable communications applications, mechanically flexible transmission lines and antennas under various bended cases were experimentally studied. The measurement results demonstrate that the printed graphene can be used for RF signal transmitting, radiating and receiving, which represents some of the essential functionalities of RF signal processing in wireless wearable communications systems. Furthermore, the printed graphene can be processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers and textiles. This work brings a step closer to the prospect to implement graphene enabled low cost and environmentally friendly wireless wearable communications systems in the near future.

  3. Highly Flexible and Conductive Printed Graphene for Wireless Wearable Communications Applications

    PubMed Central

    Huang, Xianjun; Leng, Ting; Zhu, Mengjian; Zhang, Xiao; Chen, JiaCing; Chang, KuoHsin; Aqeeli, Mohammed; Geim, Andre K.; Novoselov, Kostya S.; Hu, Zhirun

    2015-01-01

    In this paper, we report highly conductive, highly flexible, light weight and low cost printed graphene for wireless wearable communications applications. As a proof of concept, printed graphene enabled transmission lines and antennas on paper substrates were designed, fabricated and characterized. To explore its potentials in wearable communications applications, mechanically flexible transmission lines and antennas under various bended cases were experimentally studied. The measurement results demonstrate that the printed graphene can be used for RF signal transmitting, radiating and receiving, which represents some of the essential functionalities of RF signal processing in wireless wearable communications systems. Furthermore, the printed graphene can be processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers and textiles. This work brings a step closer to the prospect to implement graphene enabled low cost and environmentally friendly wireless wearable communications systems in the near future. PMID:26673395

  4. A new high intensity and short-pulse molecular beam valve.

    PubMed

    Yan, B; Claus, P F H; van Oorschot, B G M; Gerritsen, L; Eppink, A T J B; van de Meerakker, S Y T; Parker, D H

    2013-02-01

    In this paper, we report on the design and performance of a new home-built pulsed gas valve, which we refer to as the Nijmegen Pulsed Valve (NPV). The main output characteristics include a short pulse width (as short as 20 μs) combined with operating rates up to 30 Hz. The operation principle of the NPV is based on the Lorentz force created by a pulsed current passing through an aluminum strip located within a magnetic field, which opens the nozzle periodically. The amplitude of displacement of the opening mechanism is sufficient to allow the use of nozzles with up to 1.0 mm diameter. To investigate the performance of the valve, several characterizations were performed with different experimental methods. First, a fast ionization gauge was used to measure the beam intensity of the free jet emanating from the NPV. We compare free jets from the NPV with those from several other pulsed valves in current use in our laboratory. Results showed that a high intensity and short pulse-length beam could be generated by the new valve. Second, the NPV was tested in combination with a skimmer, where resonance enhanced multiphoton ionization combined with velocity map imaging was used to show that the NPV was able to produce a pulsed molecular beam with short pulse duration (~20 μs using 0.1% NO/He at 6 bars) and low rotational temperature (~1 K using 0.5% NO/Ar at 6 bars). Third, a novel two-point pump-probe method was employed which we label double delay scan. This method allows a full kinematic characterization of the molecular beam, including accurate speed ratios at different temporal positions. It was found that the speed ratio was maximum (S = 50 using 0.1% NO/He at 3 bars) at the peak position of the molecular beam and decreased when it was on the leading or falling edge. PMID:23464190

  5. A high power TWT power processing system. [for communication satellites

    NASA Technical Reports Server (NTRS)

    Farber, B. F.; Goldin, D. S.; Siegert, C.; Gourash, F.

    1974-01-01

    A power processing system (PPS) is designed for a space-type high power (200W RF) multi-collector traveling-wave tube (TWT). The basic power circuit is presented along with the simplified block diagram and the input, output, and general requirements for the PPS design are tabulated. The paper covers the PPS design as to critical TWT/PPS interface requirements, high voltage cathode/collector supply, high voltage components material, packaging, grounding and isolation, and electrical performance. The use of a single two loop control system for the regulation of cathode and collector voltages is shown to give high efficiency, excellent steady-state and transient performance characteristics, and complete protection for TWT and PPS components under transient conditions.

  6. Remotely-interrogated high data rate free space laser communications link

    DOEpatents

    Ruggiero, Anthony J.

    2007-05-29

    A system and method of remotely extracting information from a communications station by interrogation with a low power beam. Nonlinear phase conjugation of the low power beam results in a high power encoded return beam that automatically tracks the input beam and is corrected for atmospheric distortion. Intracavity nondegenerate four wave mixing is used in a broad area semiconductor laser in the communications station to produce the return beam.

  7. Type IIa Bragg grating based ultra-short DBR fiber laser with high temperature resistance.

    PubMed

    Ran, Yang; Feng, Fu-Rong; Liang, Yi-Zhi; Jin, Long; Guan, Bai-Ou

    2015-12-15

    We report on the fabrication of a thermally resistant ultra-short distributed Bragg reflector (DBR) fiber laser based on the photo inscription of two wavelength-matched type IIa gratings in a thin-core Er-doped fiber. With continuous UV exposure, each Bragg reflector initially grows as a type I grating, followed by decay in strength, and then re-grows as a type IIa grating with enhanced thermal resistance. The DBR laser, with an entire length of 13 mm, can stably operate at 600°C with single longitude mode, which provides potential applications in high temperature environments. PMID:26670491

  8. Very high-capacity short-reach VCSEL systems exploiting multicarrier intensity modulation and direct detection.

    PubMed

    Gatto, Alberto; Argenio, Debora; Boffi, Pierpaolo

    2016-06-13

    Multicarrier intensity modulation of a bandwidth-limited long-wavelength VCSEL is exploited combined to direct detection to achieve very high capacity simple systems for short-reach applications. Tailored FDM subcarriers modulation and allocation allow to match the non-uniform frequency response of the system induced by the direct modulation and detection of the FDM signal and by the uncompensated SSMF propagation, overcoming the VCSEL bandwidth limitations. A whole transported throughput ranging from 34 Gb/s to 25 Gb/s from few hundreds meters to 20 km of SSMF propagation is experimentally demonstrated even by employing a 5-GHz band VCSEL source. PMID:27410296

  9. Interplay of mulitphoton and tunneling ionization in short-wavelength-driven high-order harmonic generation

    SciTech Connect

    Gkortsas, Vasileios-Marios; Bhardwaj, Siddharth; Lai, Chien-Jen; Hong, Kyung-Han; Falcao-Filho, Edilson L.; Kaertner, Franz X.

    2011-07-15

    High-order harmonic generation efficiency is theoretically modeled and compared with experiments using 400 and 800 nm driver pulses. It is shown that, for a short drive wavelength and a Keldysh parameter larger than 1, the Ammosov-Delone-Krainov (ADK) ionization model does not give a good agreement between theory and experiment. Since the ADK ionization model only accounts for tunnel ionization, it underestimates the yield of low-order harmonics from the wings of the driver pulse. In contrast, the Yudin-Ivanov ionization model [Phys. Rev. A 64, 013409 (2001)], which accounts for both tunnel and multiphoton ionization, gives much better agreement with the experimental results.

  10. Implementing Molecular Dynamics for Hybrid High Performance Computers - 1. Short Range Forces

    SciTech Connect

    Brown, W Michael; Wang, Peng; Plimpton, Steven J; Tharrington, Arnold N

    2011-01-01

    The use of accelerators such as general-purpose graphics processing units (GPGPUs) have become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high performance computers, machines with more than one type of floating-point processor, are now becoming more prevalent due to these advantages. In this work, we discuss several important issues in porting a large molecular dynamics code for use on parallel hybrid machines - 1) choosing a hybrid parallel decomposition that works on central processing units (CPUs) with distributed memory and accelerator cores with shared memory, 2) minimizing the amount of code that must be ported for efficient acceleration, 3) utilizing the available processing power from both many-core CPUs and accelerators, and 4) choosing a programming model for acceleration. We present our solution to each of these issues for short-range force calculation in the molecular dynamics package LAMMPS. We describe algorithms for efficient short range force calculation on hybrid high performance machines. We describe a new approach for dynamic load balancing of work between CPU and accelerator cores. We describe the Geryon library that allows a single code to compile with both CUDA and OpenCL for use on a variety of accelerators. Finally, we present results on a parallel test cluster containing 32 Fermi GPGPUs and 180 CPU cores.

  11. High Resolution Imaging by Atomic Force Microscopy: Contribution of short-range force to the imaging

    NASA Astrophysics Data System (ADS)

    Eguchi, Toyoaki; Kotone, Akiyama; Masanori, Ono; Toshio, Sakurai; Yukio, Hasegawa

    2003-03-01

    Recent developments in force detection technique have made us possible to obtain atomically resolved images of the Si(111)-(7x7) surface by AFM. Compared with STM, however, its spatial resolution remains limited. In this presentation, we demonstrate that with careful pretreatment and appropriate experimental parameters, the structure of the rest-atom layer can be imaged using AFM by detecting the short-range force due to the single chemical bonding. The detection of the short-range force is verified by analysis of the frequency-shift versus distance curve (force curve). This unprecedented high resolution is achieved by reducing background forces due to the long-range interactions with small oscillation amplitude of the cantilever and an atomically sharp tip. The high temperature annealing of the cantilever assists in obtaining a bare silicon tip on the cantilever without unwanted tip-blunting, and improving the Q-factor of the cantilever. This study implies that characterization of the AFM tip in nanometer scale, not only on the apex atoms but also its shape near the apex, is important and critical for AFM high resolution imaging.

  12. Short-range variability of soil pH in a regional geochemical survey, communicating uncertainty to the data user

    NASA Astrophysics Data System (ADS)

    Ander, Louise; Knights, Kate; Lark, Murray

    2015-04-01

    The north of Ireland is well-furnished with geochemical data after completion of the Tellus survey of Northern Ireland and the Tellus Border survey of six northern counties of the Republic of Ireland. These data are of considerable interest to the agricultural sector, in particular the data on soil pH. However, a geochemical survey at regional scale cannot resolve significant variation of soil pH, in particular effects of soil management and fine-scale variation of superficial material. This leads to uncertainties in the mapped soil pH which must be accounted for when making decisions about management interventions, including more detailed local sampling. In this poster we show how uncertainty of predicted soil pH, relative to established threshold values, can be quantified by disjunctive kriging. The uncertainty is expressed in terms of probabilities. We show how this can be communicated to the data user by means of the calibrated phrases of the IPCC, using results from recent research on its efficacy to modify its presentation.

  13. Steady State Analysis of Short-wavelength, High-gainFELs in a Large Storage Ring

    SciTech Connect

    Huang, Z.; Bane, K.; Cai, Y.; Chao, A.; Hettel, R.; Pellegrini, C.; /UCLA

    2007-10-15

    Storage ring FELs have operated successfully in the low-gain regime using optical cavities. Discussions of a high-gain FEL in a storage ring typically involve a special bypass to decouple the FEL interaction from the storage ring dynamics. In this paper, we investigate the coupled dynamics of a high-gain FEL in a large storage ring such as PEP and analyze the equilibrium solution. We show that an FEL in the EUV and soft x-ray regimes can be integrated into a very bright storage ring and potentially provides three orders of magnitude improvement in the average brightness at these radiation wavelengths. We also discuss possibilities of seeding with HHG sources to obtain ultra-short, high-peak power EUV and soft x-ray pulses.

  14. Radiation Hardened, Modulator ASIC for High Data Rate Communications

    NASA Technical Reports Server (NTRS)

    McCallister, Ron; Putnam, Robert; Andro, Monty; Fujikawa, Gene

    2000-01-01

    Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values. High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency, but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with high power-efficiency (negligible HPA backoff).

  15. Short communication: Altered expression of specificity protein 1 impairs milk fat synthesis in goat mammary epithelial cells.

    PubMed

    Zhu, J J; Luo, J; Xu, H F; Wang, H; Loor, J J

    2016-06-01

    Specificity protein 1 (encoded by SP1) is a novel transcription factor important for the regulation of lipid metabolism and the normal function of various hormones in model organisms. Its potential role, if any, on ruminant milk fat is unknown. Despite the lower expression of the lipolysis-related gene ATGL (by 44 and 37% respectively), both the adenoviral overexpression and the silencing of SP1 [via short interfering (si)RNA] markedly reduced cellular triacylglycerol (TAG) content (by 28 and 25%, respectively), at least in part by decreasing the expression of DGAT1 (-36% in adenovirus treatment) and DGAT2 (-81 and -87%, respectively) that are involved in TAG synthesis. Consistent with the markedly lower expression of genes related to lipid droplet formation and secretion (TIP47 by 19 and 32%, and ADFP by 25 and 25%, respectively), cellular lipid droplet content was also decreased sharply, by 9 and 8.5%, respectively, after adenoviral overexpression of SP1 or its silencing via siRNA. Overall, the results underscored a potentially important role of SP1 in maintaining milk-fat droplet synthesis in goat mammary epithelial cells. PMID:26995134

  16. Parent Involvement in Junior High Schools: A Failure to Communicate

    ERIC Educational Resources Information Center

    Halsey, Pamela A.

    2005-01-01

    Although the nature of parent involvement changes as children get older and varies from family to family, junior high school teachers and the families they serve recognize the value of parent involvement in young adolescents' education. Teachers, parents, and students, however, are often uncertain about how to initiate parent involvement in their…

  17. The Communicative Process of Drug Resistance among High School Students.

    ERIC Educational Resources Information Center

    Alberts, J. K.; And Others

    1992-01-01

    Analyzed 69 narrative accounts of successful and unsuccessful attempts by high school students to say no to drug offers. Found peer pressure applied in approximately 70 percent of offers. Much of pressure was applied after refusal of initial offer. Simple offers were more likely with alcohol; drug offers were more likely to be persuasive and to…

  18. Development of microlens arrays for high-speed optical communication

    NASA Astrophysics Data System (ADS)

    Ko, Chih-Hsiang; Lin, Chun-Hsu; Tsai, Bor-Chen; Shih, His-Hsin; Wu, Chien-Tsung; Chao, Yu-Lin; Chou, Yu-Kon; Chu, Chun-Hsun; Chiou, Yii-Tay; Chen, Rax

    2004-09-01

    In this study, polymeric microlens arrays, well suited for high-volume and low-cost production, were developed for efficiently coupling the light from vertical-cavity surface emitting lasers (VCSELs) to multi-mode fiber ribbon. They were fabricated by microinjection molding with Ni-electroplated mold insert. Modified LIGA processes and the Ni-electroplating are used to make the master and the metallic mold insert, respectively. In this study, microinjection molding with metallocene based cyclic olefin copolymer (mCOC) was chosen to replicate microlenses. Good surface profile and high dimensional accuracy are achieved. Coupling efficiency of 55 +/- 3 % with a working distance of 400 +/- 60 micrometer is obtained. To verify its applications on high-speed interconnections, we also designed the evaluated board and set up an opto-electronic measurement platform. The high-speed measurement shows that the electrical-to-optical conversion 3dB-bandwidth is above 1.8 GHz, and the eye diagram at 2.488 Gbps is acceptable for the SONET OC-48 eye mask.

  19. Short-Range Structure of Clouds Studied by High Resolution Photography From the Surface

    NASA Astrophysics Data System (ADS)

    Schwartz, S. E.; Huang, D.; Vladutescu, D. V.

    2015-12-01

    Clouds exhibit structures at a wide range of length scales. Passive radiometry from satellite shows structure on scales of tens to thousands of kilometers, but there is much structure at short spatial scales not resolved by satellite imagery. Here we use a commercial camera having high spatial resolution (~20 μrad) and high dynamic range (16 bits in each of three color channels) in narrow field-of-view (20 mrad, 110 mrad), zenith-looking mode from the surface, to examine clouds at the scale of centimeters to a few hundred meters, focusing on non-precipitating single-layer clouds during daytime. Up-looking photography of clouds from the surface affords the further advantage, relative to satellite imagery, of black background (space) with contributions to radiance only from blue sky (Rayleigh scattering), aerosols, and clouds, permitting reconstruction of observed radiance by radiation transfer modeling. Contrast between cloudy and cloud-free sky is enhanced in Red/(Red + Blue), RRB, image Figure 1, but no unique value of RRB distinguishes a pixel as cloud vs. cloud-free. Short-range variability is characterized by the autocorrelation length scale, which is not uncommonly as short as a few meters; longer range variability, such as cloud characteristic size, separation distance, and cloud spatial organization, is also characterized. Scene reconstruction yields the 2D distribution of cloud optical depth; spatial inhomogeneity is attributed mainly to horizontal variation in vertical motion of the air and resultant condensation or evaporation associated with upward or downward motion, respectively. Alternative approaches to calculation of the radiative influence of such clouds from the autocorrelation structure of the cloud field are examined. Figure 1. RGB image of zenith sky at New York City, May 22, 2015, (field of view 21 mrad corresponding to 56 m at cloud altitude 2.6 km) showing broken single-layer cloud; corresponding RRB image; and autocorrelation of RRB image.

  20. The Effects of Music on High-intensity Short-term Exercise in Well Trained Athletes

    PubMed Central

    Jarraya, Mohamed; Chtourou, Hamdi; Aloui, Asma; Hammouda, Omar; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2012-01-01

    Purpose The purpose of this investigation was to assess the effects of listening to music during warm-up on short-term supramaximal performances during the 30-s Wingate test in highly trained athletes. Methods Twelve young male athletes (20.6±1.8 yrs, 177±4.4 cm and 72.3±5.3 kg) underwent two Wingate tests in separate sessions with a recovery period of 48 h in-between, either after a 10 min of warm-up with (MWU) or without (NMWU) music. High tempo music (>120 to 140bpm) was selected for the study. Heart rate (HR) and rate of perceived exertion (RPE) were recorded after the warm-up (for HR = average of warm-up) and immediately after the Wingate test. Results HR, RPE and the fatigue index during the Wingate test are not affected by the incorporation of music during warm-up. However, power output (Ppeak and Pmean) was significantly higher after MWU than NMWU (P<0.05). The relative increases were 4.1 ± 3.6 and 4.0 ± 3.7 W·kg−1 for Ppeak and Pmean respectively. These findings demonstrated the beneficial effect of music during warm-up on short-term supramaximal performances. Conclusions As it's a legal method and an additional aid, music may be used during warm-up before performing activities requiring powerful lower limbs’ muscles contractions during short-term supramaximal exercises. PMID:23342221

  1. Role of effective teamwork and communication in delivering safe, high-quality care.

    PubMed

    Leonard, Michael W; Frankel, Allan S

    2011-01-01

    Healthcare is delivered in an extraordinary complex environment. Despite highly skilled, dedicated clinicians, there are currently unacceptably high levels of communication failures and adverse events. Effective teamwork, in conjunction with reliable processes of care, is essential for the consistent delivery of high-quality care. Practical concepts and tools are provided that address the team behaviors of structured communication, effective assertion/critical language, psychological safety, situational awareness, and effective leadership. Examples of the mounting clinical evidence of improved patient outcomes and reduced harm resulting from effective teamwork training are cited. PMID:22069205

  2. VERY HIGH-SPEED DRILL STRING COMMUNICATIONS NETWORK

    SciTech Connect

    David S. Pixton

    2002-08-01

    Testing of recent upgrades to the drill pipe telemetry system in a 1000-ft vertical well has shown that the new system can achieve at least 1,000 ft passive transmission distance with sufficient bandwidth to accommodate a digital transmission rate of 2 Mbit/sec. Digitized data from a module at the bottom of the well has been successfully transmitted through the transmission line to the top of the well for a period of approximately one month. Manufacture of 30 prototype range 2 drill pipes has demonstrated greater simplicity of manufacturing and greater consistency of electrical characteristics from part to part, as compared to the first production run previously reported. Further work is needed to improve the high pressure capability of the system and to improve the robustness of the system in a high-vibration environment.

  3. FAST TRACK COMMUNICATION High rate straining of tantalum and copper

    NASA Astrophysics Data System (ADS)

    Armstrong, R. W.; Zerilli, F. J.

    2010-12-01

    High strain rate measurements reported recently for several tantalum and copper crystal/polycrystal materials are shown to follow dislocation mechanics-based constitutive relations, first at lower strain rates, for dislocation velocity control of the imposed plastic deformations and, then at higher rates, transitioning to nano-scale dislocation generation control by twinning or slip. For copper, there is the possibility of added-on slip dislocation displacements to be accounted for from the newly generated dislocations.

  4. Automated control and monitoring of thermal processing using high temperature, short time pasteurization.

    PubMed

    Schlesser, J E; Armstrong, D J; Cinar, A; Ramanauskas, P; Negiz, A

    1997-10-01

    High temperature, short time pasteurization was used to evaluate a computer-based system for controlling the pasteurization process, acquiring data, and monitoring records. Software was used for the control of hot water temperature, flow rate through the centrifugal timing pump, and diversion of under-processed product. Three types of control strategies were conducted: single loop, cascade, and multivariable. The single loop control strategy showed the most rapid responses to temperature changes, but the temperature response curve was slowest to return to its set point. The cascade control strategy showed slower recoveries to temperature changes, but the temperature response curve was smoother. The multivariable control strategy responded slightly faster than the cascade control strategy, and the temperature response curve was slightly smoother than the cascade control strategy. The multivariable control strategy was able to control the flow diversion valve by the use of a lethality controller. The data acquisition system, used to monitor the data obtained from the high temperature, short-time pasteurization system, was within +/- 0.1 degree C of the temperature recorded by the safety thermal limit recorder. Reliability was determined by examining the changes in the position of the flow diversion valve to identify process deviations and by comparing the changes to the event marker on circular charts. The data acquisition system was an effective alternative for monitoring the completeness of data. PMID:9361200

  5. Advanced concepts for high-power, short-pulse CO2 laser development

    NASA Astrophysics Data System (ADS)

    Gordon, Daniel F.; Hasson, Victor; von Bergmann, Hubertus; Chen, Yu-hsin; Schmitt-Sody, A.; Penano, Joseph R.

    2016-06-01

    Ultra-short pulse lasers are dominated by solid-state technology, which typically operates in the near-infrared. Efforts to extend this technology to longer wavelengths are meeting with some success, but the trend remains that longer wavelengths correlate with greatly reduced power. The carbon dioxide (CO2) laser is capable of delivering high energy, 10 micron wavelength pulses, but the gain structure makes operating in the ultra-short pulse regime difficult. The Naval Research Laboratory and Air Force Research Laboratory are developing a novel CO2 laser designed to deliver ~1 Joule, ~1 picosecond pulses, from a compact gain volume (~2x2x80 cm). The design is based on injection seeding an unstable resonator, in order to achieve high energy extraction efficiency, and to take advantage of power broadening. The unstable resonator is seeded by a solid state front end, pumped by a custom built titanium sapphire laser matched to the CO2 laser bandwidth. In order to access a broader range of mid infrared wavelengths using CO2 lasers, one must consider nonlinear frequency multiplication, which is non-trivial due to the bandwidth of the 10 micron radiation.

  6. Short-read, high-throughput sequencing technology for STR genotyping

    PubMed Central

    Bornman, Daniel M.; Hester, Mark E.; Schuetter, Jared M.; Kasoji, Manjula D.; Minard-Smith, Angela; Barden, Curt A.; Nelson, Scott C.; Godbold, Gene D.; Baker, Christine H.; Yang, Boyu; Walther, Jacquelyn E.; Tornes, Ivan E.; Yan, Pearlly S.; Rodriguez, Benjamin; Bundschuh, Ralf; Dickens, Michael L.; Young, Brian A.; Faith, Seth A.

    2013-01-01

    DNA-based methods for human identification principally rely upon genotyping of short tandem repeat (STR) loci. Electrophoretic-based techniques for variable-length classification of STRs are universally utilized, but are limited in that they have relatively low throughput and do not yield nucleotide sequence information. High-throughput sequencing technology may provide a more powerful instrument for human identification, but is not currently validated for forensic casework. Here, we present a systematic method to perform high-throughput genotyping analysis of the Combined DNA Index System (CODIS) STR loci using short-read (150 bp) massively parallel sequencing technology. Open source reference alignment tools were optimized to evaluate PCR-amplified STR loci using a custom designed STR genome reference. Evaluation of this approach demonstrated that the 13 CODIS STR loci and amelogenin (AMEL) locus could be accurately called from individual and mixture samples. Sensitivity analysis showed that as few as 18,500 reads, aligned to an in silico referenced genome, were required to genotype an individual (>99% confidence) for the CODIS loci. The power of this technology was further demonstrated by identification of variant alleles containing single nucleotide polymorphisms (SNPs) and the development of quantitative measurements (reads) for resolving mixed samples. PMID:25621315

  7. Ultrafast terawatt laser sources for high-field particle acceleration and short wavelength generation

    SciTech Connect

    Downer, M.C.; Siders, C.W.

    1996-12-31

    The Laser Sources working group concerned itself with recent advances in and future requirements for the development of laser sources relevant to high-energy physics (HEP) colliders, small scale accelerators, and the generation of short wave-length radiation. We heavily emphasized pulsed terawatt peak power laser sources for several reasons. First, their development over the past five years has been rapid and multi-faceted, and has made relativistic light intensity available to the advanced accelerator community, as well as the wider physics community, for the first time. Secondly, they have strongly impacted plasma-based accelerator research over the past two years, producing the first experimental demonstrations of the laser wakefield accelerator (LWFA) in both its resonantly-driven and self-modulated forms. Thirdly, their average power and wall-plug efficiency currently fall well short of projected requirements for future accelerators and other high average power applications, but show considerable promise for improving substantially over the next few years. A review of this rapidly emerging laser technology in the context of advanced accelerator research is therefore timely.

  8. High Efficiency Power Combining of Ka-Band TWTs for High Data Rate Communications

    NASA Technical Reports Server (NTRS)

    Wintucky, E. G.; Simons, R. N.; Vaden, K. R.; Lesny, G. G.; Glass, J. L.

    2006-01-01

    Future NASA deep space exploration missions are expected in some cases to require telecommunication systems capable of operating at very high data rates (potentially 1 Gbps or more) for the transmission back to Earth of large volumes of scientific data, which means high frequency transmitters with large bandwidth. Among the Ka band frequencies of interest are the present 500 MHz Deep Space Network (DSN) band of 31.8 to 32.3 GHz and a broader band at 37-38 GHz allocated for space science [1]. The large distances and use of practical antenna sizes dictate the need for high transmitter power of up to 1 kW or more. High electrical efficiency is also a requirement. The approach investigated by NASA GRC is a novel wave guide power combiner architecture based on a hybrid magic-T junction for combining the power output from multiple TWTs [1,2]. This architecture was successfully demonstrated and is capable of both high efficiency (90-95%, depending on frequency) and high data rate transmission (up to 622 Mbps) in a two-way power combiner circuit for two different pairs of Ka band TWTs at two different frequency bands. One pair of TWTs, tested over a frequency range of 29.1 to 29.6 GHz, consisted of two 110-115W TWTs previously used in uplink data transmission evaluation terminals in the NASA Advanced Communications Technology Satellite (ACTS) program [1,2]. The second pair was two 100W TWTs (Boeing 999H) designed for high efficiency operation (greater than 55%) over the DSN frequency band of 31.8 to 32.3 GHz [3]. The presentation will provide a qualitative description of the wave guide circuit, results for power combining and data transmission measurements, and results of computer modeling of the magic-T and alternative hybrid junctions for improvements in efficiency and power handling capability. The power combiner results presented here are relevant not only to NASA deep space exploration missions, but also to other U.S. Government agency programs.

  9. An exploratory analysis of communication sources: targeting high risk behavior among injection drug users.

    PubMed

    Bodkin, C D; La Salvia, T A

    1996-01-01

    Currently, most AIDS education and prevention programs attempt to change the high risk behavior of injection drug users (IDU's) (e.g., sharing needles and engaging in unsafe sex) through the implementation of two distinct strategies. First, empirical-rational strategies suggest that people maximize their rational self-interest. Second, normative re-education strategies suggest that people change their individual behavior when they believe that there has been change in the sociocultural norms, values, and habits around them. Both of these strategies make assumptions about how communication changes IDU's beliefs and behavior. An empirical-rational strategy emphasizes non-personal mass communications (e.g., television, radio, newspaper); while normative re-education strategies make use of personal communications (e.g. friends, family, educational outreach workers, and group discussion). The purpose of this paper is to compare these strategies by examining the impact of AIDS communication sources on the beliefs and behaviors of IDU's. PMID:10172894

  10. A high-power communications technology satellite for the 12 and 14 GHz bands.

    NASA Technical Reports Server (NTRS)

    Franklin, C. A.; Davison, E. H.

    1972-01-01

    Description of the mission, subsystems and communication capabilities of a joint Communications Technology Satellite (CTS) scheduled for launch in 1975 by the Canadian Department of Communications in cooperation with NASA. The principal objectives of the mission are TV transmission at 12 GHz to low-cost ground terminals, up-link TV transmission at 14 GHz transportable terminals, and flight tests of spacecraft subsystems and components for future communications satellites. The major advanced spacecraft subsystems are a novel superefficiency TWT design, a 0.4 mlb Mercury Bombardment ion engine for north-south station keeping, a 3-axis stabilization system to maintain a high antenna boresight pointing accuracy, a liquid metal slip ring experiment, and a lightweight extendible solar array with an initial power output greater than 1 kW.

  11. Improving Mathematical Communication Ability and Self Regulation Learning of Junior High Students by Using Reciprocal Teaching

    ERIC Educational Resources Information Center

    Qohar, Abdul; Sumarmo, Utari

    2013-01-01

    This paper presents the findings from a posttest experiment control group design by using reciprocal teaching, conducted in Indonesia University of Education to investigate students' ability in mathematical communication and self regulated learning. Subject of the study were 254 of 9th grade students from three junior high schools of high, medium,…

  12. Communications Strategies on Alcohol and Highway Safety. Volume II. High School Youth. Final Report.

    ERIC Educational Resources Information Center

    Grey Advertising, Inc., New York, NY.

    The second part of a two-part, two volume study deals with high school youth and identifies target populations and communications strategies for encouraging personal action steps to prevent drunk driving. Data, collected from interviews and questionnaires, are summarized and presented in tabular form. One fourth of high schoolers in a…

  13. Developing Students' Literacy Skills Using High-Tech Speech-Generating Augmentative and Alternative Communication Devices

    ERIC Educational Resources Information Center

    Wilkins, Julia; Ratajczak, Amy

    2009-01-01

    This article outlines practical techniques for developing literacy skills in users of high-tech speech-generating augmentative and alternative communication (AAC) devices. The recommended strategies are intended for general classroom teachers who teach literacy skills to students with typical speech. Many students who use high-tech AAC devices…

  14. RAPID COMMUNICATION: Percolation modelling for highly aligned polycrystalline superconducting tapes

    NASA Astrophysics Data System (ADS)

    Rutter, N. A.; Glowacki, B. A.; Evetts, J. E.

    2000-11-01

    Surface and bulk texture measurements have been carried out on highly aligned NiFe tapes, suitable for use as coated conductor substrates. Data from small-area electron backscatter diffraction measurements are compared with those from bulk x-ray analysis in the development of a two-dimensional percolation model, and the two are shown to give very similar results. No evidence of grain-to-grain correlation is found. The model is then developed to assess how the properties of a superconducting layer grown epitaxially on buffered tapes will depend on parameters such as sample size, grain size and the extent of grain alignment.

  15. Ion Beams in Short-Pulse, High Intensity Laser Matter Interactions.

    NASA Astrophysics Data System (ADS)

    Lasinski, B. F.; Langdon, A. B.; Still, C. H.; Tabak, M.; Town, R. P. J.; Kruer, W. L.; Wilks, S. C.; Welch, D. R.

    2002-11-01

    Experiments on the interaction of short pulse high intensity lasers with thin foils have produced intense ion beams with surprisingly good emittance. We report on explicit PIC and hybrid particle-fluid simulations motivated by these experiments. In addition, we study the focusing of these beams and their possible collective effects. The LSP code footnote D. R. Welch, et al, Nucl. Inst. Meth. Phys. Res. A 242, 134 (2001). uses a direct implicit particle-in-cell algorithm in 2 or 3 dimensions to solve for the beam particles and the background particles are treated as a fluid. Implications for the fast ignitor concept footnote M. Tabak, et al, Phys. Plasmas 1, 1626 (1994). in which energetic fast particles transport energy to the high-density compressed fuel will be discussed.

  16. Atomic short-range order and incipient long-range order in high-entropy alloys

    NASA Astrophysics Data System (ADS)

    Singh, Prashant; Smirnov, A. V.; Johnson, D. D.

    2015-06-01

    Within density-functional theory, we apply an electronic-structure-based thermodynamic theory to calculate short-ranged order (SRO) in homogeneously disordered substitutional N -component alloys, and its electronic origin. Using the geometric properties of an (N -1 ) simplex that describes the Gibbs (compositional) space, we derive the analytic transform of the SRO eigenvectors that provides a unique description of high-temperature SRO in N -component alloys and the incipient low-temperature long-range order. We apply the electronic-based thermodynamic theory and the new general analysis to ternaries (A 1 Cu-Ni-Zn and A 2 Nb-Al-Ti) for validation, and then to quinary Al-Co-Cr-Fe-Ni high-entropy alloys for predictive assessment.

  17. Establishing an Infrastructure for High-Throughput Short-Interfering RNA Screening.

    PubMed

    Yin, Hongwei; Sereduk, Chris; Tang, Nanyun

    2016-01-01

    RNA interference (RNAi) is a readily available research tool that can be used to accelerate the identification and functional validation of a multitude of new candidate drug targets by experimentally perturbing gene expression and function. High-throughput RNAi technology using libraries of short-interfering RNA (siRNA) makes it possible to rapidly identify genes and biomarkers associated with biological processes such as diseases or a cellular response to therapy. Thus, RNAi-based screening is an extremely powerful technology that can provide tremendous insights into the mechanisms of action and contexts of vulnerability of a particular drug treatment. This chapter describes the infrastructure requirements needed to successfully perform HT-RNAi screening. Information on the methodology, instrumentation, experimental design, and workflow aspects is provided, as well as insights on how to successfully implement a high-throughput RNAi screen. PMID:27581280

  18. Fiber Laser Front Ends for High-Energy Short Pulse Lasers

    SciTech Connect

    Dawson, J W; Liao, Z M; Mitchell, S; Messerly, M; Beach, R; Jovanovic, I; Brown, C; Payne, S A; Barty, C J

    2005-01-18

    We are developing an all fiber laser system optimized for providing input pulses for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal solutions for these systems as they are highly reliable and once constructed they can be operated with ease. Furthermore, they offer an additional benefit of significantly reduced footprint. In most labs containing equivalent bulk laser systems, the system occupies two 4'x8' tables and would consist of 10's if not a 100 of optics which would need to be individually aligned and maintained. The design requirements for this application are very different those commonly seen in fiber lasers. High energy lasers often have low repetition rates (as low as one pulse every few hours) and thus high average power and efficiency are of little practical value. What is of high value is pulse energy, high signal to noise ratio (expressed as pre-pulse contrast), good beam quality, consistent output parameters and timing. Our system focuses on maximizing these parameters sometimes at the expense of efficient operation or average power. Our prototype system consists of a mode-locked fiber laser, a compressed pulse fiber amplifier, a ''pulse cleaner'', a chirped fiber Bragg grating, pulse selectors, a transport fiber system and a large flattened mode fiber amplifier. In our talk we will review the system in detail and present theoretical and experimental studies of critical components. We will also present experimental results from the integrated system.

  19. proovread: large-scale high-accuracy PacBio correction through iterative short read consensus

    PubMed Central

    Hackl, Thomas; Hedrich, Rainer; Schultz, Jörg; Förster, Frank

    2014-01-01

    Motivation: Today, the base code of DNA is mostly determined through sequencing by synthesis as provided by the Illumina sequencers. Although highly accurate, resulting reads are short, making their analyses challenging. Recently, a new technology, single molecule real-time (SMRT) sequencing, was developed that could address these challenges, as it generates reads of several thousand bases. But, their broad application has been hampered by a high error rate. Therefore, hybrid approaches that use high-quality short reads to correct erroneous SMRT long reads have been developed. Still, current implementations have great demands on hardware, work only in well-defined computing infrastructures and reject a substantial amount of reads. This limits their usability considerably, especially in the case of large sequencing projects. Results: Here we present proovread, a hybrid correction pipeline for SMRT reads, which can be flexibly adapted on existing hardware and infrastructure from a laptop to a high-performance computing cluster. On genomic and transcriptomic test cases covering Escherichia coli, Arabidopsis thaliana and human, proovread achieved accuracies up to 99.9% and outperformed the existing hybrid correction programs. Furthermore, proovread-corrected sequences were longer and the throughput was higher. Thus, proovread combines the most accurate correction results with an excellent adaptability to the available hardware. It will therefore increase the applicability and value of SMRT sequencing. Availability and implementation: proovread is available at the following URL: http://proovread.bioapps.biozentrum.uni-wuerzburg.de Contact: frank.foerster@biozentrum.uni-wuerzburg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25015988

  20. Short-term high-altitude pre-exposure improves neurobehavioral ability

    PubMed Central

    Guo, Wenyun; Chen, Guozhu; Qin, Jun; Zhang, Jihang; Guo, Xubin; Yu, Jie; Song, Pan; Lu, Wei; Xu, Baida; Li, Jiabei; Ding, Xiaohan

    2016-01-01

    This study aims to evaluate the effect of the duration of high-altitude (HA) pre-exposure on human neurobehavioral parameters including mood states and cognitive performance at HA. One hundred and eleven healthy individuals (ranging in age from 18 to 35 years) were recruited to participate in this study. They were divided into two groups: a 4-day short-term HA pre-exposure group (n=57) and a 3-month long-term HA pre-exposure group (n=54). All participants lived in the area at 400 m altitude above sea level before pre-exposure to HA. They were then transported to 3700 m plateau for either a 4-day or a 3-month HA pre-exposure, and finally delivered to 4400 m plateau. On the last day of pre-exposure at 3700 m and on the 10th day at 4400 m, neurobehavioral parameters of the participants in the two groups were evaluated. At the end of pre-exposure and on the 10th day of HA exposure, participants in the short-term group had significantly lower negative mood states, better cognitive performance with higher sensorimotor, attention, and psychomotor abilities, and less acute mountain sickness in comparison with the participants in the long-term pre-exposure group. Our field study with large samples showed that in comparison with 3-month long-term pre-exposure, 4-day short-term HA pre-exposure at 3700 m has a better effect in improving human neurobehavioral parameters including mood states and cognitive performance and reducing acute mountain sickness when exposed to a HA at 4400 m. PMID:26966781

  1. Communications: Nanomagnetic shielding: High-resolution NMR in carbon allotropes.

    PubMed

    Kim, Y; Abou-Hamad, E; Rubio, A; Wågberg, T; Talyzin, A V; Boesch, D; Aloni, S; Zettl, A; Luzzi, D E; Goze-Bac, C

    2010-01-14

    The understanding and control of the magnetic properties of carbon-based materials is of fundamental relevance in applications in nano- and biosciences. Ring currents do play a basic role in those systems. In particular the inner cavities of nanotubes offer an ideal environment to investigate the magnetism of synthetic materials at the nanoscale. Here, by means of (13)C high resolution NMR of encapsulated molecules in peapod hybrid materials, we report the largest diamagnetic shifts (down to -68.3 ppm) ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon doping. This diamagnetic shift can be externally controlled by in situ modifications such as doping or electrostatic charging. Moreover, defects such as C-vacancies, pentagons, and chemical functionalization of the outer nanotube quench this diamagnetic effect and restore NMR signatures to slightly paramagnetic shifts compared to nonencapsulated molecules. The magnetic interactions reported here are robust phenomena independent of temperature and proportional to the applied magnetic field. The magnitude, tunability, and stability of the magnetic effects make the peapod nanomaterials potentially valuable for nanomagnetic shielding in nanoelectronics and nanobiomedical engineering. PMID:20095656

  2. K-band high power latching switch. [communication satellite system

    NASA Technical Reports Server (NTRS)

    Mlinar, M. J.; Piotrowski, W. S.; Raue, J. E.

    1980-01-01

    A 19 GHz waveguide latching switch with a bandwidth of 1400 MHz and an exceptionally low insertion loss of 0.25 dB was demonstrated. The RF and driver ferrites are separate structures and can be optimized individually. This analysis for each structure is separately detailed. Basically, the RF section features a dual turnstile junction. The circulator consists of a dielectric tube which contains two ferrite rods, and a dielectric spacer separating the ferrite parts along the center of symmetry of the waveguide to form two turnstiles. This subassembly is indexed and locked in the center of symmetry of a uniform junction of three waveguides by the metallic transformers installed in the top and bottom walls of the housing. The switching junction and its actuating circuitry met all RF performance objectives and all shock and vibration requirements with no physical damage or performance degradation. It exceeds thermal requirements by operating over a 100 C temperature range (-44 C to +56 C) and has a high power handling capability allowing up to 100 W of CW input power.

  3. Highly-charged heavy-ion production with short pulse lasers

    SciTech Connect

    Logan, G.; Bitmire, T.; Perry, M.; Anderson, O.; Kuehl, T.

    1998-01-27

    This MathCAD document describes a possible approach using a PW -class short pulse laser to form a useful number (10{sup 12}) of high and uniform charge state ions with low ion temperature (<< 100 eV) and low momentum spread ({delta}p{sub z}/p, < 10{sup -4} ) for injection into heavy-ion fusion accelerators. As a specific example, we consider here Xenon{sup +26}, which has an ionization energy E{sub i} {approximately} 860 eV for the 26th electron, and a significantly higher ionization potential of 1500 eV for the 27th electron because of the M-shell jump. The approach considered here may be used for other ion species as well. The challenge is not simply to produce high charge states with a laser (the ITEP group [Sharkov] have used long pulse CO{sub 2} lasers to create many charge states of chromium up to helium-like Cr{sup +25} by collisional ionization at high Te), nor just to create such high charge states more selectively by field (tunneling) ionization at higher intensities and shorter pulses. Rather, the challenge is to create a selected uniform high charge state, in useful numbers, while keeping the ion temperature and momentum spread small, and avoiding subsequent loss of ion charge state due to recombination and charge-exchange with background gas atoms during extraction into a useful low emittance beam.

  4. Short communication: Genetic variants of Sarcocystis cruzi in infected Malaysian cattle based on 18S rDNA.

    PubMed

    Ng, Yit Han; Fong, Mun Yik; Subramaniam, Vellayan; Shahari, Shahhaziq; Lau, Yee Ling

    2015-12-01

    Sarcocystis species are pathogenic parasites that infect a wide range of animals, including cattle. A high prevalence of cattle sarcocystosis has been reported worldwide, but its status is unknown in Malaysia. This study focused on utilizing 18S rDNA to identify Sarcocystis species in Malaysian cattle and to determine their genetic variants. In this study, only Sarcocystis cruzi was detected in Malaysian cattle. The intra-species S. cruzi phylogenetic tree analysis and principal coordinate analysis (PCoA), respectively displayed two minor groups among the parasite isolates. This finding was supported by high Wright FST value (FST=0.647). The definitive hosts (dogs) may play a fundamental role in the development of S. cruzi genetic variants. Additionally, the existence of microheterogeneity within the S. cruzi merozoites and/or distinct genetic variants arisen from independent merozoites in mature sarcocysts, possibly contributed to the existence of intra-species variations within the population. PMID:26679818

  5. Reflectivity of plasmas created by high-intensity, ultra-short laser pulses

    SciTech Connect

    Gold, D.M.

    1994-06-01

    Experiments were performed to characterize the creation and evolution of high-temperature (T{sub e}{approximately}100eV), high-density (n{sub e}>10{sup 22}cm{sup {minus}3}) plasmas created with intense ({approximately}10{sup 12}-10{sup 16}W/cm{sup 2}), ultra-short (130fs) laser pulses. The principle diagnostic was plasma reflectivity at optical wavelengths (614nm). An array of target materials (Al, Au, Si, SiO{sub 2}) with widely differing electronic properties tested plasma behavior over a large set of initial states. Time-integrated plasma reflectivity was measured as a function of laser intensity. Space- and time-resolved reflectivity, transmission and scatter were measured with a spatial resolution of {approximately}3{mu}m and a temporal resolution of 130fs. An amplified, mode-locked dye laser system was designed to produce {approximately}3.5mJ, {approximately}130fs laser pulses to create and nonintrusively probe the plasmas. Laser prepulse was carefully controlled to suppress preionization and give unambiguous, high-density plasma results. In metals (Al and Au), it is shown analytically that linear and nonlinear inverse Bremsstrahlung absorption, resonance absorption, and vacuum heating explain time-integrated reflectivity at intensities near 10{sup 16}W/cm{sup 2}. In the insulator, SiO{sub 2}, a non-equilibrium plasma reflectivity model using tunneling ionization, Helmholtz equations, and Drude conductivity agrees with time-integrated reflectivity measurements. Moreover, a comparison of ionization and Saha equilibration rates shows that plasma formed by intense, ultra-short pulses can exist with a transient, non-equilibrium distribution of ionization states. All targets are shown to approach a common reflectivity at intensities {approximately}10{sup 16}W/cm{sup 2}, indicating a material-independent state insensitive to atomic or solid-state details.

  6. Evaluating the relationship between breakfast pattern and short-term memory in junior high school girls.

    PubMed

    Ahmadi, A; Sohrabi, Z; Eftekhari, M H

    2009-05-01

    The aim of this study was to evaluate the relationship between breakfast pattern and short-term memory in guidance-school students. Memory improves for subjects who have eaten breakfast. It appears that breakfast consumption influences cognition via several mechanisms. What children eat for breakfast before going to school is very important. A total of 150 junior high school girls were taken from a subject pool in four schools in Shiraz (capital of the Fars Province in Iran). They filled out the socio-economic questionnaires as well as food frequency questionnaires for breakfast and provided two-three day breakfast records in two different seasons and their short-term memories were evaluated by Weksler test socio-economic conditions and dietary intakes were analyzed. The results of the study showed that there was no correlation between parents job, students mean age and their school grades with their memory scores. Dietary analysis demonstrated a negative correlation between local soup consumption in breakfast and memory scores. Food record analysis showed no correlation between fat, cholesterol, protein, vitamin B6, B12, calorie and iodine intake in breakfast and memory scores, but there was a positive correlation between carbohydrate, iron and vitamin B3 intake in breakfast and memory scores, similarly there was a positive correlation between B12 intake in the breakfast and students' average school grades during the year. PMID:19634483

  7. Quercetin alleviates inflammation after short-term treatment in high-fat-fed mice.

    PubMed

    Das, Nilanjan; Sikder, Kunal; Bhattacharjee, Surajit; Majumdar, Suchandra Bhattacharya; Ghosh, Santinath; Majumdar, Subrata; Dey, Sanjit

    2013-06-01

    Consumption of a high-fat diet (HFD) promotes reactive oxygen species (ROS) which ultimately trigger inflammation. The aim of this study was to investigate the role of Moringa oleifera leaf extract (MoLE) and its active component quercetin in preventing NF-κB-mediated inflammation raised by short-term HFD. Quercetin was found to be one of the major flavonoid components from HPLC of MoLE. Swiss mice were fed for 15 days on HFD, both with or without MoLE/quercetin. The antioxidant profile was estimated from liver homogenate. NF-κB and some relevant inflammatory markers were evaluated by immunoblotting, RT-PCR and ELISA. Significantly (P < 0.05) lower antioxidant profile and higher lipid peroxidation was found in HFD group compared to control (P < 0.05). Increased nuclear import of NF-κB and elevated expressions of pro-inflammatory markers were further manifestations in the HFD group. All these changes were reversed in the MoLE/quercetin-treated groups with significant improvement of antioxidant activity compared to the HFD group. MoLE was found to be rich in polyphenols and both MoLE and quercetin showed potent free radical and hydroxyl radical quenching activity. Thus, the present study concluded that short-term treatment with MoLE and its constituent quercetin prevent HFD-mediated inflammation in mice. PMID:23644882

  8. Inequivalence of Phase and Time Delay in High Harmonic Generation with Short Pulses

    NASA Astrophysics Data System (ADS)

    Peng, Dian; Pi, Liangwen; Starace, Anthony

    2016-05-01

    When mixing two (or more) laser pulses, the phase difference and the time delay are two crucial parameters. For long pulses, the relative phase and the time delay are equivalent: for example, cos(ω1 t) + cos(ω2 t + ϕ) = cos(ω1 t) + cos [ω2(t + ϕ /ω2) ] , i.e. in the extreme case of infinitely long pulses, the phase ϕ can be viewed as a time delay ϕ /ω2 between the two pulses. However, for ultra short pulses, this equivalence breaks down: the carrier-envelope phase can't be viewed as equivalent to a time delay between two pulse envelopes. Our quantum simulations show that the inequivalence of the phase and the time delay in short pulses can result in significantly different high-order harmonic generation spectra, with up to an order of magnitude difference in intensity and up to about 10 harmonic orders of difference in cutoff energy. Further analysis shows the underlying physics of such difference. Exposing this inequivalence directly for the first time, our work provides new insights into pulse shaping and related issues for both experimentalists and theorists. This work was supported in part by NSF Grant No. PHYS-1505492.

  9. Effects of High Intensity White Noise on Short-Term Memory for Position in a List and Sequence

    ERIC Educational Resources Information Center

    Daee, Safar; Wilding, J. M.

    1977-01-01

    Seven experiments are described investigating the effecy of high intensity white noise during the visual presentation of words on a number of short-term memory tasks. Examines results relative to position learning and sequence learning. (Editor/RK)

  10. Short Communication: Expression of Transporters and Metabolizing Enzymes in the Female Lower Genital Tract: Implications for Microbicide Research

    PubMed Central

    Zhou, Tian; Hu, Minlu; Cost, Marilyn; Poloyac, Samuel

    2013-01-01

    Abstract Topical vaginal microbicides have been considered a promising option for preventing the male-to-female sexual transmission of HIV; however, clinical trials to date have not clearly demonstrated robust and reproducible effectiveness results. While multiple approaches may help enhance product effectiveness observed in clinical trials, increasing the drug exposure in lower genital tract tissues is a compelling option, given the difficulty in achieving sufficient drug exposure and positive correlation between tissue exposure and microbicide efficacy. Since many microbicide drug candidates are substrates of transporters and/or metabolizing enzymes, there is emerging interest in improving microbicide exposure and efficacy through local modulation of transporters and enzymes in the female lower genital tract. However, no systematic information on transporter/enzyme expression is available for ectocervical and vaginal tissues of premenopausal women, the genital sites most relevant to microbicide drug delivery. The current study utilized reverse transcriptase polymerase chain reaction (RT-PCR) to examine the mRNA expression profile of 22 transporters and 19 metabolizing enzymes in premenopausal normal human ectocervix and vagina. Efflux and uptake transporters important for antiretroviral drugs, such as P-gp, BCRP, OCT2, and ENT1, were found to be moderately or highly expressed in the lower genital tract as compared to liver. Among the metabolizing enzymes examined, most CYP isoforms were not detected while a number of UGTs such as UGT1A1 were highly expressed. Moderate to high expression of select transporters and enzymes was also observed in mouse cervix and vagina. The implications of this information on microbicide research is also discussed, including microbicide pharmacokinetics, the utilization of the mouse model in microbicide screening, as well as the in vivo functional studies of cervicovaginal transporters and enzymes. PMID:23607746

  11. Short communication: Amino trap column improves the separation of methylimidazoles, 5-hydroxymethyl-2-furaldehyde, and sugars in Maillard reaction.

    PubMed

    Xu, Xian-Bing; Liu, Ding-Bo; Yu, Shu-Juan; Zhao, Zhen-Gang; Yu, Pei

    2014-11-01

    A simultaneous analysis of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde in the Maillard reaction was improved by use of an amino trap column. Analysis was carried out by using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) coupled with an amino trap column. The amino trap column was a useful tool to improve the separation of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde. This technique is useful for simultaneous analysis of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde in risk assessment for dairy products. PMID:25200783

  12. Short communication: the preruminant calf as a model for characterizing the effects of vitamin D status in the neonate.

    PubMed

    Nonnecke, B J; Reinhardt, T A; Waters, W R

    2009-11-01

    The objective of this study was to evaluate the feasibility of using the preruminant dairy calf as a model for evaluating effects of vitamin D status in the neonate. Because the newborn calf can be sustained during the first weeks of life solely on a fluid diet having a defined composition, has documented nutritional requirements, and is minimally affected by repeated samplings of peripheral blood, it has the potential to serve as a model for characterizing nutrient-specific effects on the growth and health of the neonate. Colostrum-fed Holstein bull calves (n = 13) entered the trial at approximately 4 d of age. All calves were fed a custom-formulated milk replacer devoid of vitamin D. Plasma 25-hydroxyvitamin D(3) concentrations in all calves were determined on a regular basis beginning at d 0. Using this information, low- and high-status groups of calves were established by subcutaneous administration of 25-hydroxyvitamin D(3). To maintain targeted plasma 25-hydroxyvitamin D(3) concentrations in low (<30 ng/mL) and high (>60 ng/mL) vitamin D-status calves, low-status calves (n = 6) received a total of 8,600 IU (2,225 IU/wk) of vitamin D during the experimental period and high-status calves (n = 7) received 54,000 IU (13,500 IU/wk). Concentrations of 25-hydroxyvitamin D(3) in low-status calves averaged 27 ng/mL, compared with 78 ng/mL in high-status calves, and were less at all sampling times from d 7 to d 28. Concentrations of 1,25-dihydroxyvitamin D(3) and 25-hydroxyvitamin D(3) were not correlated. Calcium, magnesium, and phosphorous concentrations were unaffected by 25-hydroxyvitamin D(3) administration; however, plasma calcium and 1,25-dihydroxyvitamin D(3) concentrations were correlated. Calcium and magnesium concentrations decreased with age but remained within normal ranges for dairy cattle. These results indicate that it is possible to predictably control vitamin D status over a 28-d period and suggest that the preruminant calf might be useful as a model

  13. Short communication: Multi-trait estimation of genetic parameters for milk protein composition in the Danish Holstein.

    PubMed

    Gebreyesus, G; Lund, M S; Janss, L; Poulsen, N A; Larsen, L B; Bovenhuis, H; Buitenhuis, A J

    2016-04-01

    Genetic parameters were estimated for the major milk proteins using bivariate and multi-trait models based on genomic relationships between animals. The analyses included, apart from total protein percentage, αS1-casein (CN), αS2-CN, β-CN, κ-CN, α-lactalbumin, and β-lactoglobulin, as well as the posttranslational sub-forms of glycosylated κ-CN and αS1-CN-8P (phosphorylated). Standard errors of the estimates were used to compare the models. In total, 650 Danish Holstein cows across 4 parities and days in milk ranging from 9 to 481d were selected from 21 herds. The multi-trait model generally resulted in lower standard errors of heritability estimates, suggesting that genetic parameters can be estimated with high accuracy using multi-trait analyses with genomic relationships for scarcely recorded traits. The heritability estimates from the multi-trait model ranged from low (0.05 for β-CN) to high (0.78 for κ-CN). Genetic correlations between the milk proteins and the total milk protein percentage were generally low, suggesting the possibility to alter protein composition through selective breeding with little effect on total milk protein percentage. PMID:26805988

  14. Isolation and analysis of tetracycline-resistant Mycoplasma agalactiae strains from an infected goat herd in Cyprus - short communication.

    PubMed

    Filioussis, George; Ioannou, Ioannis; Petridou, Evanthia; Avraam, Maria; Giadinis, Nektarios D; Kritas, Spyridon K

    2013-09-01

    A major concern with the use of tetracycline against mycoplasmas is the development of resistance. Infections in small ruminants due to tetracyclineresistant Mycoplasma agalactiae strains are becoming a frequent problem worldwide. In the present paper the detection and analysis of three tetracycline-resistant M. agalactiae strains, isolated from infected goats in Cyprus, are reported. The three field isolates were identified as M. agalactiae by polymerase chain reaction (PCR) showing 98% identity to the M. agalactiae PG2 reference strain. Furthermore, they were found sensitive to tylosin, enrofloxacin, spiramycin and lincomycin. In contrast, they were resistant to tetracycline. None of the putative genes [tet(M), tet(O) and tet(S)] that commonly contribute to high-level resistance to tetracycline could be amplified from their genome. Contrarily, the field isolates were found to carry ISMag1, an insertion sequence related to the IS30 family of mobile elements. Although ISMag1 is widely believed to induce high-frequency chromosomal rearrangements resulting in phenotypic changes of microorganisms, its potential role in tetracycline resistance of mycoplasmas requires further studies. PMID:23921341

  15. High-dose short-term administration of naringin did not alter talinolol pharmacokinetics in humans.

    PubMed

    Nguyen, M A; Staubach, P; Tamai, I; Langguth, P

    2015-02-20

    Naringin is considered the major causative ingredient of the inhibition of intestinal drug uptake by grapefruit juice. Moreover, it is contained in highly dosed nutraceuticals available on the market. A controlled, open, randomized, crossover study was performed in 10 healthy volunteers to investigate the effect of high-dose naringin on the bioavailability of talinolol, a substrate of intestinal organic anion-transporting polypeptide (OATP)-mediated uptake. Following 6-day supplementation with 3 capsules of 350 mg naringin daily, 100mg talinolol were administered orally with 3 capsules of the same dietary supplement (1050 mg naringin) on the seventh day. This test treatment was compared to 100mg talinolol only (control). The results showed that short-term high-dose naringin supplementation did not significantly affect talinolol pharmacokinetics. Geometric mean ratios of test versus control ranged between 0.90 and 0.98 for talinolol c(max), AUC(0-48 h), AUC(0-∞), t(1/2) and A(e(0-48 h)). The high dose may provoke inhibition of the efflux transporter P-glycoprotein (P-gp) which counteracts the uptake inhibition. As disintegration and dissolution processes are required for the solid dosage form, dissolved naringin may arrive at the site of interaction after talinolol is already absorbed. In conclusion, the effect of nutraceuticals on drug pharmacokinetics can deviate from that observed when administered as food component due to the different dose and dosage form. PMID:25486333

  16. Forward voltage short-pulse technique for measuring high power laser array junction temperature

    NASA Technical Reports Server (NTRS)

    Meadows, Byron L. (Inventor); Amzajerdian, Frazin (Inventor); Barnes, Bruce W. (Inventor); Baker, Nathaniel R. (Inventor)

    2012-01-01

    The present invention relates to a method of measuring the temperature of the P-N junction within the light-emitting region of a quasi-continuous-wave or pulsed semiconductor laser diode device. A series of relatively short and low current monitor pulses are applied to the laser diode in the period between the main drive current pulses necessary to cause the semiconductor to lase. At the sufficiently low current level of the monitor pulses, the laser diode device does not lase and behaves similar to an electronic diode. The voltage across the laser diode resulting from each of these low current monitor pulses is measured with a high degree of precision. The junction temperature is then determined from the measured junction voltage using their known linear relationship.

  17. A high-charge and short-pulse RF photocathode gun for wake-field acceleration

    NASA Astrophysics Data System (ADS)

    Gai, W.; Li, X.; Conde, M.; Power, J.; Schoessow, P.

    1998-02-01

    In this paper we present a design report on 1-1/2 cell, L-Band RF photocathode gun which is capable of generating and accelerating electron beams with peak currents >10 kA. We address several critical issues of high-current RF photoinjectors such as longitudinal space charge effect, and transverse emittance growth. Unlike conventional short electron pulse generation, this design does not require magnetic pulse compression. Based on numerical simulations using SUPERFISH and PARMELA, this design will produce 100 nC beam at 18 MeV with r.m.s. bunch length 1.25 mm and normalized transverse emittance 108 mm mrad. Applications of this source beam for wake-field acceleration are also discussed.

  18. Study of short haul high-density V/STOL transportation systems, volume 1

    NASA Technical Reports Server (NTRS)

    Solomon, H. L.

    1972-01-01

    The relative advantages of STOL aircraft concepts were examined by simulating the operations of a short haul high-density intercity STOL system set in two arenas, the California corridor and the Chicago-Detroit-Cleveland triangle, during the 1980 time period. The study was constrained to the use of three aircraft concepts designated as the deflected slipstream turboprop, externally blown flap, and augmentor wing turbofan configurations. The projected demographic, economic, travel demand, and travel characteristics of the representative arenas were identified. The STOL airline operating scenarios were then formulated and through the use of the aerospace modal split simulation program, the traveler modal choices involving alternative STOL concepts were estimated in the context of the total transportation environment for 1980. System combinations that presented the best potential for economic return and traveler acceptance were then identified for each STOL concept.

  19. Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

    SciTech Connect

    Higginson, D P; McNaney, J M; Swift, D C; Bartal, T; Hey, D S; Pape, S L; Mackinnon, A; Mariscal, D; Nakamura, H; Nakanii, N; Beg, F N

    2010-04-22

    A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.

  20. High power, short pulses ultraviolet laser for the development of a new x-ray laser

    SciTech Connect

    Meixler, L.; Nam, C.H.; Robinson, J.; Tighe, W.; Krushelnick, K.; Suckewer, S.; Goldhar, J.; Seely, J.; Feldman, U.

    1989-04-01

    A high power, short pulse ultraviolet laser system (Powerful Picosecond-Laser) has been developed at the Princeton Plasma Physics Laboratory (PPPL) as part of experiments designed to generate shorter wavelength x-ray lasers. With the addition of pulse compression and a final KrF amplifier the laser output is expected to have reached 1/3-1/2 TW (10/sup 12/ watts) levels. The laser system, particularly the final amplifier, is described along with some initial soft x-ray spectra from laser-target experiments. The front end of the PP-Laser provides an output of 20--30 GW (10/sup 9/ watts) and can be focussed to intensities of /approximately/10/sup 16/ W/cm/sup 2/. Experiments using this output to examine the effects of a prepulse on laser-target interaction are described. 19 refs., 14 figs.

  1. Tunable, high peak power terahertz radiation from optical rectification of a short modulated laser pulse.

    PubMed

    Gordon, Daniel F; Ting, Antonio; Alexeev, Ilya; Fischer, Richard; Sprangle, Phillip; Kapetenakos, Christos A; Zigler, Arie

    2006-07-24

    A new way of generating high peak power terahertz radiation using ultra-short pulse lasers is demonstrated. The optical pulse from a titanium:sapphire laser system is stretched and modulated using a spatial filtering technique to produce a several picosecond long pulse modulated at the terahertz frequency. A collinear type II phase matched interaction is realized via angle tuning in a gallium selenide crystal. Peak powers of at least 1.5 kW are produced in a 5 mm thick crystal, and tunability is demonstrated between 0.7 and 2.0 THz. Simulations predict that 150 kW of peak power can be produced in a 5 mm thick crystal. The technique also allows for control of the terahertz bandwidth. PMID:19516863

  2. Enhancement and quenching of high-intensity focused ultrasound cavitation activity via short frequency sweep gaps.

    PubMed

    Hallez, Loïc; Lee, Judy; Touyeras, Francis; Nevers, Aymeric; Ashokkumar, Muthupandian; Hihn, Jean-Yves

    2016-03-01

    This letter reports on the use of frequency sweeps to probe acoustic cavitation activity generated by high-intensity focused ultrasound (HIFU). Unprecedented enhancement and quenching of HIFU cavitation activity were observed when short frequency sweep gaps were applied in negative and positive directions, respectively. It was revealed that irrespective of the frequency gap, it is the direction and frequency sweep rate that govern the cavitation activity. These effects are related to the response of bubbles generated by the starting frequency to the direction of the frequency sweep, and the influence of the sweep rate on growth and coalescence of bubbles, which in turn affects the active bubble population. These findings are relevant for the use of HIFU in chemical and therapeutic applications, where greater control of cavitation bubble population is critical. PMID:26584998

  3. Detector response to high repetition rate ultra-short laser pulses. I

    NASA Astrophysics Data System (ADS)

    Zakharova, I. K.; Rafailov, Michael K.

    2015-05-01

    Optical nonlinearities in semiconductors and semiconductor detectors have been widely investigated and exploited for many scientific and industrial applications. The correlation of optical and electronic characteristics in these detector materials under exposure of ultra-short laser pulses at high pulse repetition rates is still not very well known. These effects may be quite beneficial for many applications ranging from chemical and biological sensing to light-induced superconductivity. In this paper, we discuss the effect of extended bleaching in order to demonstrate sensing applications of such phenomenon as an example. Pump-probe measurements in bulk semiconductors will be presented to quantify the transient absorption dynamics and relate this to the electronic response of the detector devices. This effect is not limited semiconductors and may affect other matter states and electronic structures, like dielectrics.

  4. Short communication: feasibility and acceptability of developing a multisite clinical cohort of transgender people with HIV infection.

    PubMed

    Poteat, Tonia C; Hanna, David B; Althoff, Keri N

    2015-09-01

    Transgender women bear a disproportionate burden of HIV, yet data among this population are not routinely collected in HIV clinical cohorts. Brief surveys and follow-up qualitative interviews were conducted with principal investigators or designated representatives of 17 HIV clinical cohorts to determine the acceptability and feasibility of pooling transgender-specific data from existing HIV clinical cohort studies. Twelve of 17 sites reported that they already collect gender identity data but not consistently. Others were receptive to collecting this information. Many also expressed interest in a study of clinical outcomes among HIV-infected transgender women using pooled data across cohorts. The collection of longitudinal data on transgender people living with HIV is acceptable and feasible for most North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) cohorts. HIV clinical cohort studies should make efforts to include transgender individuals and develop the tools to collect quality data on this high-need population. PMID:26126154

  5. Short communication: Effects of prepartum diets supplemented with rolled oilseeds on Brix values and fatty acid profile of colostrum.

    PubMed

    Salehi, R; Ambrose, D J; Oba, M

    2016-05-01

    The objective of this study was to evaluate effects of oilseeds supplemented in prepartum diets on colostrum quality. Thirty-nine dry pregnant Holstein cows (14 primiparous and 25 multiparous cows) were blocked by body condition score and parity and assigned to 1 of 3 experimental diets containing rolled oilseeds at 8% of dietary dry matter (canola seed or sunflower seed) or no oilseed (control) at 35 d before the expected calving date. Canola seed is high in oleic acid and sunflower seed is high in linoleic acid content. Colostrum samples were collected at the first milking after calving, and concentrations of nutrient composition, fatty acid profile, and Brix value (an indicator IgG concentration) were determined. Cows fed sunflower seeds before calving produced colostrum with greater crude protein content (15.0 vs. 12.9%), colostral Brix values (24.3 vs. 20.3%), and conjugated linoleic acid concentration (18:2 cis-9,trans-11; 0.64 vs. 0.48%) compared with those fed canola seed. Positive effects of feeding sunflower seed might be mediated by ruminal metabolism of linoleic acid and subsequent enhanced production of conjugated linoleic acid. Oilseed supplementation in prepartum diets of dairy cows also altered fatty acid profile of colostrum in a way to reflect fatty acid profile of the supplemented oilseeds except for oleic acid. In conclusion, prepartum feeding of sunflower seed increased colostral Brix value, an indicator of colostral IgG concentration, compared with that of canola seed, but its mode of action and effects on health and productivity of calves need to be investigated. PMID:26971161

  6. Short communication: Genetic analysis for fertility traits of heifers and cows from smallholder dairy farms in a tropical environment.

    PubMed

    Buaban, S; Duangjinda, M; Suzuki, M; Masuda, Y; Sanpote, J; Kuchida, K

    2015-07-01

    The objective of this study was to estimate genetic parameters for various fertility traits on Holstein upgraded dairy heifers and cows in a smallholder system under tropical conditions using data sets from the Thailand national recording scheme. The investigated traits were age at first service (AFS), age at first calving (AFC), days from calving to first service (DTFS), days between first and last service (DFLS), days open (DO), calving interval (CI), number of services per conception (NSPC), and conception at first service (FSC). The data consisted of 68,555, 34,401, and 54,004 records on heifers, primiparous, and multiparous cows, respectively, calving between 1996 and 2011. Gibbs sampling was employed to obtain (co)variance components using both univariate and bivariate analyses with linear and threshold animal models. Virgin heifers had better fertility performance than primiparous and multiparous cows. The reproductive performance in primiparous cows was inferior compared with multiparous cows. Cows with higher Holstein-Friesian blood showed lower reproductive efficiency. Estimated heritabilities for most of the fertility traits were 0.04 or less except for AFS (0.26) and AFC (0.25). The estimated genetic correlations among fertility traits within parity indicated that selection for cows with high conception rate could lead to shortened DO and CI, as well as DTFS. The FSC and NSPC could be used as the best indicators for heifer and cow fertility and could be complemented by other traits, which were genetically considered as different traits such as DTFS and DFLS in terms of a fertility index. This would enable efficient selection for better fertility. Genetic correlations for fertility traits in primiparous and multiparous cows were very high (>0.90), but those between heifers and cows were lower (0.03 to 0.83). The latter results indicated that fertility traits of heifers and cows should be considered as different traits. PMID:25981071

  7. Space Weather effects on airline communications in the high latitude regions

    NASA Astrophysics Data System (ADS)

    Honary, Farideh

    2014-05-01

    Efficient air traffic management depends on reliable communications between aircraft and the air traffic control centres at all times. At high latitudes, and especially on polar routing, VHF ground infrastructure does not exist and the aircraft have to rely on HF radio for communications. HF relies on reflections from the ionosphere to achieve long distance communications. Unfortunately the high latitude ionosphere is affected by space weather events. During such events HF radio communication can be severely disrupted and aircraft are forced to use longer low latitude routes with consequent increased flight time, fuel consumption and cost. This presentation describes a new research programme at the University of Lancaster in collaboration with the University of Leicester, Solar Metrics Ltd and Natural Resources Canada for the development of a nowcasting and forecasting HF communications tool designed for the particular needs of civilian airlines. This project funded by EPSRC will access a wide variety of solar and interplanetary measurements to derive a complete picture of space weather disturbances affecting radio absorption and reflection

  8. Short communication: in vitro ruminal fermentability of a modified corn cultivar expressing a thermotolerant α-amylase.

    PubMed

    Hu, W; Persia, M E; Kung, L

    2010-10-01

    The fermentability of a corn cultivar that expresses a thermostable α-amylase (CA3272) was evaluated under various in vitro conditions. The CA3272 corn was developed as a replacement to microbial enzyme additions during the high-temperature processing of corn to produce ethanol. The α-amylase activity in the corn might have the potential for positive effects on ruminant performance if incorporated into the ration. Four corn cultivars were evaluated in an in vitro ruminal fermentation where the digestion of starch was measured after 6 h. The cultivars included a flint corn, an opaque corn, CA3272, and its near-isogenic counterpart (IC). The flint corn produced less total volatile fatty acids (18.4 mM) than the other 3 corns (average of 25.3 mM), supporting the fact that it had the highest concentration of prolamins, which are negatively associated with starch availability. A second 6-h in vitro ruminal fermentation evaluated mixtures of the CA3272 and IC corns (0, 25, 50, 75, and 100% concentrations of CA3272). Total volatile fatty acid production was not different among treatments for any proportions of CA3272. In a third in vitro experiment, there was a small but significant difference in starch degradation of CA3272 compared with IC (90.6 vs. 89.7%) but this difference is most likely not biologically relevant. In a fourth in vitro experiment, CA3272 and IC were incubated in water at 40 and 65°C for 24 h. Degradation of starch from native amylase activity at 40°C was 1.99 and 1.60% for CA3272 and IC, respectively, but when they were incubated at 65°C, starch degradation was 10.56 and 0.85% for CA3272 and IC, respectively. These data demonstrate that amylase activity in CA3272 is expressed at a high temperature (65°C) but at the physiological temperature expected in a rumen of a cow (39-40°C), expression of amylase activity does not appear to be sufficient to have any positive (or negative) effects on ruminal metabolism. PMID:20855018

  9. Short Communication: Anti-HIV-1 Envelope Immunoglobulin Gs in Blood and Cervicovaginal Samples of Beninese Commercial Sex Workers

    PubMed Central

    Batraville, Laurie-Anne; Richard, Jonathan; Veillette, Maxime; Labbé, Annie-Claude; Alary, Michel; Guédou, Fernand; Kaufmann, Daniel E.; Poudrier, Johanne

    2014-01-01

    Abstract Characterization of the immune correlates of protection against HIV infection is crucial for the development of preventive strategies. This study examined HIV-1 envelope (Env) glycoproteins, specifically immunoglobulin G (IgG), in systemic and mucosal compartments of female Beninese commercial sex workers (CSWs). Samples of 23 HIV-1-positive and 20 highly exposed HIV-1-seronegative (HESN) CSWs were studied. HIV-1 Env-specific IgG detection in sera and cervicovaginal lavages (CVLs) from the study population was done by cell-based ELISA. The HIV neutralizing activity was evaluated with a neutralization assay. The HIV-1-specific antibody-dependent cellular cytotoxicity (ADCC) response of the cohort was measured with a FACS-based assay evaluating the ADCC-mediated elimination of gp120-coated target cells. No anti-HIV-1 Env-specific IgG neutralizing or ADCC activities were detected in samples from HESN CSWs. Samples from HIV-1-infected CSWs presented ADCC activity in both sera and CVLs. Anti-Env IgG from sera and CVLs from HIV-1-infected CSWs preferentially recognized Env in its CD4-bound conformation. HIV-1-infected CSWs have ADCC-mediating IgG that preferentially recognizes Env in its CD4-bound conformation at the mucosal site. PMID:25354025

  10. Short Communication Validation of EST-derived microsatellite markers for two Cerrado-endemic Campomanesia (Myrtaceae) species.

    PubMed

    Miranda, E A G C; Boaventura-Novaes, C R D; Braga, R S; Reis, E F; Pinto, J F N; Telles, M P C

    2016-01-01

    We assessed the transferability of 120 EST-derived Eucalyptus microsatellite primers to Campomanesia adamantium and C. pubescens. Both species are berry trees native to the Brazilian Cerrado, and population genetic information is poor. Twelve markers were used to analyze the genetic variability of four sampled populations. Regarding DNA extraction, we sampled leaf tissues from two populations of each species (80 individuals). Of the 120 primers evaluated, 87 did not amplify any PCR products, and 21 rendered nonspecific amplification. Twelve primers were successfully transferred, providing a low combined probability of genetic identity for both species (5.718 x 10(-10) for C. adamantium; 1.182 x 10(-11) for C. pubescens) and a high probability of paternity exclusion (0.99939 for C. adamantium; 0.99982 for C. pubescens). The average number of alleles in the polymorphic loci was 6.8 for C. adamantium and 7.8 for C. pubescens, ranging from 2 to 16 alleles per locus. The observed heterozygosity values for C. adamantium and C. pubescens were 0.504 and 0.503, respectively, and the expected heterozygosity values for C. adamantium and C. pubescens were 0.517 and 0.579, respectively. The populations exhibited structured genetic variability with qP values of 0.105 for C. adamantium and 0.249 for C. pubescens. Thus, we concluded that these 12 microsatellite markers, transferred from Eucalyptus, were efficient for population genetic studies of C. adamantium and C. pubescens. PMID:26985928

  11. Photography (Graphic Communications). Industrial Arts, Senior High--Level II. North Dakota Senior High Industrial Arts Curriculum Guides.

    ERIC Educational Resources Information Center

    Poehls, Eddie; And Others

    This course guide for a photography course is one of four developed for the graphic communications area in the North Dakota senior high industrial arts education program. (Eight other guides are available for two other areas of Industrial Arts--energy/power and production.) Part 1 provides such introductory information as a definition and…

  12. Graphic Arts (Graphic Communications). Industrial Arts, Senior High--Level II. North Dakota Senior High Industrial Arts Curriculum Guides.

    ERIC Educational Resources Information Center

    Poehls, Eddie; And Others

    This course guide for a graphic arts course is one of four developed for the graphic communications area in the North Dakota senior high industrial arts education program. (Eight other guides are available for two other areas of Industrial Arts--energy/power and production.) Part 1 provides such introductory information as a definition and…

  13. Short communication: Methicillin-resistant Staphylococcus aureus in bulk tank milk of dairy cows and effect of swine population density.

    PubMed

    Locatelli, C; Cremonesi, P; Bertocchi, L; Zanoni, M G; Barberio, A; Drigo, I; Varisco, G; Castiglioni, B; Bronzo, V; Moroni, P

    2016-03-01

    The methicillin-resistant Staphylococcus aureus (MRSA) has recently frequently been reported in dairy cattle, usually with low prevalence. The livestock-associated MRSA (LA-MRSA) ST398 is especially involved in cases of subclinical and clinical mastitis. Swine carry LA-MRSA without clinical symptoms and are considered its reservoir and shedder. People exposed to swine are particularly at risk of LA-MRSA colonization. Environments with relevant livestock density are a demonstrated risk factor for humans to be carriers of a LA-MRSA. This work investigated dairy farms located in an area with a high livestock density, mainly represented by swine. Bulk tank milk samples from 224 dairy farms were collected, and their status was defined as MRSA-positive or MRSA-negative based on culture on chromogenic medium. The number of fattening swine and of fattening swine herds was calculated in an area of 3 km around each dairy farm through georeferencing. The probability of a Staphylococcus aureus-positive dairy farm to be MRSA positive based on the extent of potential infective pressure due to swine density was calculated. Both the number of swine herds and the number of swine were associated with the MRSA status of dairy herds. The 9 MRSA isolated were typed by multi-locus sequence typing and spa-typing, and characterized for their virulence factors and antimicrobial resistance profiles. The ST and spa-types detected are consistent with those present in the Italian swine population. Virulence and resistance profiles are mostly consistent with the types detected. This work provides the first evidence of the epidemiological challenge exerted by the density of the swine population on MRSA in dairy cows. PMID:26805972

  14. Short communication: Factors affecting vitamin B12 concentration in milk of commercial dairy herds: An exploratory study.

    PubMed

    Duplessis, M; Pellerin, D; Cue, R I; Girard, C L

    2016-06-01

    Only bacteria can synthesize vitamin B12, and this requires adequate Co supply. The natural source of vitamin B12 in human diets comes from animal products, especially those from ruminants. This study aimed to describe variability regarding vitamin B12 concentration in milk among and within commercial dairy herds in early lactation. A secondary objective was to explore potential causes for this variability such as genetic variation and diet characteristics. In total, 399 dairy cows (135 primiparous and 264 multiparous; 386 Holstein and 13 Jersey cows) in 15 commercial herds were involved. Milk samples were taken at 27.4±4.1 and 55.4±4.1d in milk. Neither parity (primiparous vs. multiparous) nor sampling time affected milk concentrations of vitamin B12. Nevertheless, vitamin B12 concentration in milk was highly variable among and within dairy herds. The lowest vitamin B12 concentration in milk of cows was observed in the Jersey herd. Among herds, vitamin B12 concentration in milk ranged from 2,309 to 3,878 pg/mL; one glass (250mL) of milk from those herds would provide between 23 and 40% of the vitamin B12 recommended daily allowance. Among individual cows, however, this provision varied between 16 and 57% of the recommendation. In spite of the limited size of the studied population, the heritability value was 0.23, suggesting that genetic selection could modify milk vitamin B12 concentration. We observed a positive relationship between milk vitamin B12 concentration and dietary acid detergent fiber content and a negative relationship between milk concentration of vitamin B12 and dietary crude protein content. PMID:27040783

  15. Short communication: The effects of dry matter and length of storage on the composition and nutritive value of alfalfa silage.

    PubMed

    Santos, M C; Kung, L

    2016-07-01

    During the ensiling of feeds, various processes result in chemical changes that can affect their ultimate nutritive value at feed out. The primary objective of this study was to evaluate the effect of prolonged ensiling times on potential changes in in vitro digestibility of neutral detergent fiber (NDF-D) of alfalfa ensiled at about 33% [low dry matter (DM), LDM] or 45% (high DM, HDM) whole-plant DM. Alfalfa from the same field (direct chopped or wilted) was chopped with a conventional forage harvester set for a theoretical length of cut of 0.95 cm and ensiled in mini silos for 45, 180, 270, and 360 d. Fresh forages and silages were analyzed for nutrient content, fermentation end-products, and 30-h NDF-D. The pH of the fresh forages ranged from 6.1 to 6.2 and decreased to approximately 4.7 and 4.3 in HDM and LDM silages, respectively. Production of acids and alcohols were less in HDM compared with LDM as expected. Concentrations of soluble protein and NH3-N also increased with time of storage as expected but soluble protein was greater, whereas NH3-N was lower in HDM compared with LDM silage. The effect of length of storage and DM on hemicellulose and NDF concentrations were very small, whereas DM content at harvest tended to slightly increase the concentration of acid detergent fiber in HDM compared with LDM up to 270 d of storage. The NDF-D was greater in fresh forage compared with corresponding silages. However, time of storage between 45 and 360 d had no effect on the NDF-D of alfalfa silage, regardless of DM concentration at ensiling. PMID:27179862

  16. Short Communication: Diagnosis of Pneumocystis jirovecii Pneumonia by Detection of DNA in Blood and Oropharyngeal Wash, Compared with Sputum.

    PubMed

    van Halsema, Clare; Johnson, Leann; Baxter, Joanne; Douthwaite, Sam; Clowes, Yvonne; Guiver, Malcolm; Ustianowski, Andrew

    2016-05-01

    Molecular diagnostic methods on lower respiratory specimens for Pneumocystis pneumonia (PCP) are recommended, but specimens can be difficult to obtain. This study examined the diagnostic use of PCP polymerase chain reaction (PCR) on oropharyngeal wash (OPW) and blood versus sputum (spontaneous and induced) to find faster, simpler, and less invasive diagnostic methods. We prospectively recruited consenting adults with symptoms consistent with PCP. Real-time PCR targeted the Pneumocystis mitochondrial large subunit ribosomal RNA gene, using the aforementioned specimens. Clinical data were collected from routine records. Forty-five participants provided 45 sputa, 31 OPW, and 41 blood samples. Median age was 39 years and 41 (91%) were male, with median CD4 count being 64 cells/μL. Sputum PCR was positive in 27/45 (60%) participants. Comparative sensitivity of OPW was 9/19 (47%, 95% confidence interval [CI] 23-71) and blood 12/24 (50%, 95% CI 29-71) participants, both with specificity 100%. Including only samples obtained ≤2 days after start of treatment, sensitivity of OPW was 80% (8/10, 95% CI 51-100), that of blood was 57% (8/14, 95% CI 29-86), and that of combined tests was 88% (14/16, 95% CI 70-100). In 14/16 individuals with PCP and specimens obtained ≤2 days after start of treatment, diagnosis was possible using nonrespiratory samples. Despite moderate sensitivity of individual tests, combined PCP PCR on early blood and OPW specimens had high sensitivity and could reduce the need for invasive procedures. There were no false-positive results on nonrespiratory samples. Sampling and laboratory methods use routine technology and so require few additional resources. PMID:26739439

  17. Short Communication: Do Cytomegalovirus Antibody Levels Associate with Age-Related Syndromes in HIV Patients Stable on Antiretroviral Therapy?

    PubMed

    Brunt, Samantha J; Cysique, Lucette A; Lee, Silvia; Burrows, Sally; Brew, Bruce J; Price, Patricia

    2016-06-01

    HIV(+) persons stable on antiretroviral therapy (ART) face early onset of age-related diseases. This may arise from a high burden of cytomegalovirus (CMV). To address the role of CMV, we investigated univariate and multivariate associations between markers of systemic and endothelial inflammation, vascular damage, insulin resistance (IR), neurocognitive decline, and antibodies reactive with CMV. In this study, HIV(+) participants (n = 91) aged >45 years with <50 copies HIV RNA/ml plasma after >2 years on ART were assessed for cardiovascular risk (the D:A:D algorithm), type II diabetes (the HOMA-IR index), and neurocognitive performance. Blood samples were assayed for lipids, T cells, insulin, glucose, C-reactive protein, CX3CL1, sTNF-R1, total immunoglobulin G (IgG), and antibodies reactive with CMV lysate, glycoprotein B, or immediate-early-1. Levels of antibodies detected with the three antigens were tightly correlated. Levels of CMV lysate antibody were higher in patients than in age-matched healthy controls and reflected their nadir CD4 T-cell count (p = .001), total IgG (p = .02), and age (p = .08). Levels of CMV lysate antibody correlated with D:A:D score (p = .04), neurocognitive performance (p = .045), and fasting insulin (p = .02). In multivariable analyses, some associations reflected the effect of age, but CMV lysate antibody and CD8 T-cell counts were significant predictors of the HOMA-IR index (R(2) = 0.09, p = .01) independent of age. We conclude that associations between levels of CMV antibodies, cardiovascular risk, and neurocognitive health in HIV(+) patients stable on ART are moderated by age-associated increases in response to CMV, while CMV antibodies may be independently linked with IR. PMID:26876416

  18. An overview of LLNL high-energy short-pulse technology for advanced radiography of laser fusion experiments

    NASA Astrophysics Data System (ADS)

    Barty, C. P. J.; Key, M.; Britten, J.; Beach, R.; Beer, G.; Brown, C.; Bryan, S.; Caird, J.; Carlson, T.; Crane, J.; Dawson, J.; Erlandson, A. C.; Fittinghoff, D.; Hermann, M.; Hoaglan, C.; Iyer, A.; Jones, L., II; Jovanovic, I.; Komashko, A.; Landen, O.; Liao, Z.; Molander, W.; Mitchell, S.; Moses, E.; Nielsen, N.; Nguyen, H.-H.; Nissen, J.; Payne, S.; Pennington, D.; Risinger, L.; Rushford, M.; Skulina, K.; Spaeth, M.; Stuart, B.; Tietbohl, G.; Wattellier, B.

    2004-12-01

    The technical challenges and motivations for high-energy, short-pulse generation with NIF and possibly other large-scale Nd : glass lasers are reviewed. High-energy short-pulse generation (multi-kilojoule, picosecond pulses) will be possible via the adaptation of chirped pulse amplification laser techniques on NIF. Development of metre-scale, high-efficiency, high-damage-threshold final optics is a key technical challenge. In addition, deployment of high energy petawatt (HEPW) pulses on NIF is constrained by existing laser infrastructure and requires new, compact compressor designs and short-pulse, fibre-based, seed-laser systems. The key motivations for HEPW pulses on NIF is briefly outlined and includes high-energy, x-ray radiography, proton beam radiography, proton isochoric heating and tests of the fast ignitor concept for inertial confinement fusion.

  19. Improvement of short tandem repeat analysis of samples highly contaminated by humic acid.

    PubMed

    Seo, Seung Bum; Jin, Hong Xuan; Lee, Hye Young; Ge, Jianye; King, Jonathan L; Lyoo, Sung Hee; Shin, Dong Hoon; Lee, Soong Deok

    2013-10-01

    We investigated several methods for obtaining successful short tandem repeat (STR) results from high-humic acid (HA)-content samples. DNA purification efficiency was tested for QIAquick(®) PCR Purification, QIAamp(®) DNA Investigator and Prepfiler™ Forensic DNA Extraction kits. HA-removal capacity of Inhibitor Remover and InhibitEX(®) Tablet was tested. Experiments on overcoming HA effects on STR amplification were conducted using an AmpliTaq Gold(®) DNA Polymerase and a TaKaRa Ex Taq™ Hot Start Version (Ex Taq HS) with BSA addition. QIAquick kit was most efficient in HA removal and Ex Taq HS showed high resistance to HA. Increasing the amounts of Taq polymerases and BSA addition were shown to be efficient in overcoming PCR inhibition, but BSA addition was superior to the former method. Inhibitor Remover and InhibitEX(®) Tablet did not positively affect the STR results. This study will help achieve better STR results with high-HA-content samples. PMID:24112347

  20. Digital fragment analysis of short tandem repeats by high-throughput amplicon sequencing.

    PubMed

    Darby, Brian J; Erickson, Shay F; Hervey, Samuel D; Ellis-Felege, Susan N

    2016-07-01

    High-throughput sequencing has been proposed as a method to genotype microsatellites and overcome the four main technical drawbacks of capillary electrophoresis: amplification artifacts, imprecise sizing, length homoplasy, and limited multiplex capability. The objective of this project was to test a high-throughput amplicon sequencing approach to fragment analysis of short tandem repeats and characterize its advantages and disadvantages against traditional capillary electrophoresis. We amplified and sequenced 12 muskrat microsatellite loci from 180 muskrat specimens and analyzed the sequencing data for precision of allele calling, propensity for amplification or sequencing artifacts, and for evidence of length homoplasy. Of the 294 total alleles, we detected by sequencing, only 164 alleles would have been detected by capillary electrophoresis as the remaining 130 alleles (44%) would have been hidden by length homoplasy. The ability to detect a greater number of unique alleles resulted in the ability to resolve greater population genetic structure. The primary advantages of fragment analysis by sequencing are the ability to precisely size fragments, resolve length homoplasy, multiplex many individuals and many loci into a single high-throughput run, and compare data across projects and across laboratories (present and future) with minimal technical calibration. A significant disadvantage of fragment analysis by sequencing is that the method is only practical and cost-effective when performed on batches of several hundred samples with multiple loci. Future work is needed to optimize throughput while minimizing costs and to update existing microsatellite allele calling and analysis programs to accommodate sequence-aware microsatellite data. PMID:27386092

  1. Solar Cell Short Circuit Current Errors and Uncertainties During High Altitude Calibrations

    NASA Technical Reports Server (NTRS)

    Snyder, David D.

    2012-01-01

    High altitude balloon based facilities can make solar cell calibration measurements above 99.5% of the atmosphere to use for adjusting laboratory solar simulators. While close to on-orbit illumination, the small attenuation to the spectra may result in under measurements of solar cell parameters. Variations of stratospheric weather, may produce flight-to-flight measurement variations. To support the NSCAP effort, this work quantifies some of the effects on solar cell short circuit current (Isc) measurements on triple junction sub-cells. This work looks at several types of high altitude methods, direct high altitude meas urements near 120 kft, and lower stratospheric Langley plots from aircraft. It also looks at Langley extrapolation from altitudes above most of the ozone, for potential small balloon payloads. A convolution of the sub-cell spectral response with the standard solar spectrum modified by several absorption processes is used to determine the relative change from AMO, lscllsc(AMO). Rayleigh scattering, molecular scatterin g from uniformly mixed gases, Ozone, and water vapor, are included in this analysis. A range of atmosph eric pressures are examined, from 0. 05 to 0.25 Atm to cover the range of atmospheric altitudes where solar cell calibrations a reperformed. Generally these errors and uncertainties are less than 0.2%

  2. Glucose Homeostasis During Short-term and Prolonged Exposure to High Altitudes

    PubMed Central

    Ader, Marilyn; Bergman, Richard N.

    2015-01-01

    Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis. PMID:25675133

  3. Communication Satisfaction, Organizational Citizenship Behavior and the Relationship to Student Achievement in High Schools

    ERIC Educational Resources Information Center

    Blanchard, Gayle A.

    2012-01-01

    This study used a correlational design that allowed the researcher to examine the relationship among communication satisfaction, organizational citizenship behaviors (OCB) and student achievement. High school teachers were surveyed from a convenience sample of 12 school districts in Arizona. Established instruments were used to survey…

  4. Communication Strategies Used by High School English Language Learners in Multilingual Classrooms

    ERIC Educational Resources Information Center

    Spromberg, Sarah

    2011-01-01

    In this study, twenty-five high school English language learners were observed in their classrooms in a New York City public school while they worked in small groups. All observations were video recorded or done by the researcher while in the classrooms. The videos were then transcribed. Communication strategies that the participants used were…

  5. Challenge Study: A Project-Based Learning on a Wireless Communication System at Technical High School

    ERIC Educational Resources Information Center

    Terasawa, Ikuo

    2016-01-01

    The challenge study is a project based learning curriculum at Technical High School aimed at the construction of a wireless communication system. The first period was engineering issues in the construction of an artificial satellite and the second period was a positional locating system based on the general purpose wire-less device--ZigBee device.…

  6. InfoMall: An Innovative Strategy for High-Performance Computing and Communications Applications Development.

    ERIC Educational Resources Information Center

    Mills, Kim; Fox, Geoffrey

    1994-01-01

    Describes the InfoMall, a program led by the Northeast Parallel Architectures Center (NPAC) at Syracuse University (New York). The InfoMall features a partnership of approximately 24 organizations offering linked programs in High Performance Computing and Communications (HPCC) technology integration, software development, marketing, education and…

  7. Communication about Contraception and Knowledge of Oral Contraceptives amongst Norwegian High School Students.

    ERIC Educational Resources Information Center

    Hansen, Thomas; Skjeldestad, Finn Egil

    2003-01-01

    Examines communication about contraception and specific knowledge of oral contraceptives (OCs) in a sample of Norwegian high school students. More females than males discussed contraception at least monthly. Discussions were predominantly held with peers and not adults. Females were far more knowledgeable about OCs than males. The most significant…

  8. Think, Speak, Succeed!...Applied Oral Communications Activities for High School Students.

    ERIC Educational Resources Information Center

    Turlington, Anita; Timms, Keith

    This module contains speaking assignments for high school students that are taken from six different career areas. Each career section begins with a brief introduction to the career and a communications profile of the person interviewed. These pages can be copied and given to students as handouts. Each section also contains some assignments…

  9. EMERGING AIR QUALITY MODELING TECHNOLOGY FOR HIGH PERFORMANCE COMPUTING AND COMMUNICATION ENVIRONMENTS

    EPA Science Inventory

    To demonstrate applications of the HPCC technologies in air quality models, we organized the Specialty Evening Session 1, "Emerging Air Quality Modeling Technologies for High Performance Computing and Communication Environment" as a part of the Twenty First NATO/CCMS Internationa...

  10. Federal High Performance Computing and Communications Program. The Department of Energy Component.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Office of Energy Research.

    This report, profusely illustrated with color photographs and other graphics, elaborates on the Department of Energy (DOE) research program in High Performance Computing and Communications (HPCC). The DOE is one of seven agency programs within the Federal Research and Development Program working on HPCC. The DOE HPCC program emphasizes research in…

  11. Buried Treasure: The Theory and Practice of Communicative Action in an Urban High School Newspaper.

    ERIC Educational Resources Information Center

    Novek, Eleanor M.

    An urban high school English/journalism class used the production of a community-focused newspaper as a strategy for the self-determination of young African Americans. The intervention emphasized social relations--focusing on specific verbal and social skills which young people can use in determining and reaching a variety of communication goals…

  12. Electronic Communication and Its Influence on Parental Involvement in High School

    ERIC Educational Resources Information Center

    Watkins, Aaron

    2013-01-01

    This study investigated the effect of electronic communication has on parent's involvement with their high school child's education. The No Child Left Behind Act of 2001 (NCLB) specifically requires that schools find ways to increase parental involvement; this requirement stemmed from evidence that involvement tends to decline as the students…

  13. The design of a linear L-band high power amplifier for mobile communication satellites

    NASA Technical Reports Server (NTRS)

    Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

    1990-01-01

    A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

  14. The DOE Program in HPCC: High-Performance Computing and Communications.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Office of Energy Research.

    This document reports to Congress on the progress that the Department of Energy has made in 1992 toward achieving the goals of the High Performance Computing and Communications (HPCC) program. Its second purpose is to provide a picture of the many programs administered by the Office of Scientific Computing under the auspices of the HPCC program.…

  15. Conflicts and Communication between High-Achieving Chinese American Adolescents and Their Parents

    ERIC Educational Resources Information Center

    Qin, Desiree Baolian; Chang, Tzu-Fen; Han, Eun-Jin; Chee, Grace

    2012-01-01

    Drawing on in-depth interview data collected on 18 high-achieving Chinese American students, the authors examine domains of acculturation-based conflicts, parent and child internal conflicts, and conflict resolution in their families. Their analyses show that well-established negative communication patterns in educational expectations, divergent…

  16. Short communication: Cytokine profiles from blood mononuclear cells of dairy cows classified with divergent immune response phenotypes.

    PubMed

    Martin, C E; Paibomesai, M A; Emam, S M; Gallienne, J; Hine, B C; Thompson-Crispi, K A; Mallard, B A

    2016-03-01

    Genetic selection for enhanced immune response has been shown to decrease disease occurrence in dairy cattle. Cows can be classified as high (H), average, or low responders based on antibody-mediated immune response (AMIR), predominated by type-2 cytokine production, and cell-mediated immune response (CMIR) through estimated breeding values for these traits. The purpose of this study was to identify in vitro tests that correlate with in vivo immune response phenotyping in dairy cattle. Blood mononuclear cells (BMC) isolated from cows classified as H-AMIR and H-CMIR through estimated breeding values for immune response traits were stimulated with concanavalin A (ConA; Sigma Aldrich, St. Louis, MO) and gene expression, cytokine production, and cell proliferation was determined at multiple time points. A repeated measures model, which included the effects of immune response group, parity, and stage of lactation, was used to compare differences between immune response phenotype groups. The H-AMIR cows produced more IL-4 protein than H-CMIR cows at 48 h; however, no difference in gene expression of type-2 transcription factor GATA3 or IL4 was noted. The BMC from H-CMIR cows had increased production of IFN-γ protein at 48, 72, and 96 h compared with H-AMIR animals. Further, H-CMIR cows had increased expression of the IFNG gene at 16, 24, and 48 h post-treatment with ConA, although expression of the type-1 transcription factor gene TBX21 did not differ between immune response groups. Although proliferation of BMC increased from 24 to 72 h after ConA stimulation, no differences were found between the immune response groups. Overall, stimulation of H-AMIR and H-CMIR bovine BMC with ConA resulted in distinct cytokine production profiles according to genetically defined groups. These distinct cytokine profiles could be used to define disease resistance phenotypes in dairy cows according to stimulation in vitro; however, other immune response phenotypes should be assessed

  17. Short communication: grazing pattern of dairy cows that were selected for divergent residual feed intake as calves.

    PubMed

    Gregorini, P; Waghorn, G C; Kuhn-Sherlock, B; Romera, A J; Macdonald, K A

    2015-09-01

    The aim of this study was to investigate and assess differences in the grazing pattern of 2 groups of mature dairy cows selected as calves for divergent residual feed intake (RFI). Sixteen Holstein-Friesian cows (471±31kg of body weight, 100 d in milk), comprising 8 cows selected as calves (6-8 mo old) for low (most efficient: CSCLowRFI) and 8 cows selected as calves for high (least efficient: CSCHighRFI) RFI, were used for the purpose of this study. Cows (n=16) were managed as a single group, and strip-grazed (24-h pasture allocation at 0800h) a perennial ryegrass sward for 31 d, with measurements taken during the last 21 d. All cows were equipped with motion sensors for the duration of the study, and jaw movements were measured for three 24-h periods during 3 random nonconsecutive days. Measurements included number of steps and jaw movements during grazing and rumination, plus fecal particle size distribution. Jaw movements were analyzed to identify bites, mastication (oral processing of ingesta) during grazing bouts, chewing during rumination, and to calculate grazing and rumination times for 24-h periods. Grazing and walking behavior were also analyzed in relation to the first meal of the day after the new pasture was allocated. Measured variables were subjected to multivariate analysis. Cows selected for low RFI as calves appeared to (a) prioritize grazing and rumination over idling; (b) take fewer steps, but with a higher proportion of grazing steps at the expense of nongrazing steps; and (c) increase the duration of the first meal and commenced their second meal earlier than CSCHighRFI. The CSCLowRFI had fewer jaw movements during eating (39,820 vs. 45,118 for CSCLowRFI and CSCHighRFI, respectively), more intense rumination (i.e., 5 more chews per bolus), and their feces had 30% less large particles than CSCHighRFI. These results suggest that CSCLowRFI concentrate their grazing activity to the time when fresh pasture is allocated, and graze more efficiently

  18. Persuading girls to take elective physical science courses in high school: Who are the credible communicators?

    NASA Astrophysics Data System (ADS)

    Koballa, Thomas R., Jr.

    Eighth-grade girls (N=257) randomly selected from nine different public junior high schools in central Texas were questioned in order to identify the communicators whom they perceive as highly credible regarding reasons for taking elective physical science courses in high school and the attributes associated with these communicators. Four persons were each identified by better than 10 percent of the sample as the best person to try to convince junior high school girls to take elective physical science courses in high school. In order of perceived credibility, these persons are father, woman science teacher, mother, and boy high school student. Slight variations in the order of perceived credibility were found when the responses from girls of the different ethnic groups represented in the sample (Caucasian, Hispanic, Black, and Asian) were examined separately. Attributes listed by the respondents for father, woman science teacher, mother, and boy high school student were examined and classified into the categories of prestige, trustworthiness, similarity, attractiveness, and power. Prestige and trustworthiness are the attributes associates most frequently with communicators identified as highly credible. Implications of the present study and suggestions for further research are discussed.

  19. Short communication: Association of milk fatty acids with early lactation hyperketonemia and elevated concentration of nonesterified fatty acids.

    PubMed

    Mann, S; Nydam, D V; Lock, A L; Overton, T R; McArt, J A A

    2016-07-01

    The objective of our study was to extend the limited research available on the association between concentrations of milk fatty acids and elevated nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) concentrations in early lactation dairy cattle. Measurement of milk fatty acids for detection of cows in excessive negative energy balance has the potential to be incorporated in routine in-line monitoring systems. Blood samples were taken from 84 cows in second or greater lactation 3 times per week between 3 to 14 d in milk. Cows were characterized as hyperketonemic (HYK) if blood BHB concentration was ≥1.2mmol/L at least once and characterized as having elevated concentrations of NEFA (NEFAH) if serum NEFA concentration was ≥1mmol/L at least once. Composition of colostrum and milk fatty acids at wk 2 postpartum was used to investigate the potential diagnostic value of individual fatty acids and fatty acid ratios for the correct classification of cows with NEFA and BHB concentrations above these thresholds, respectively. Receiver operating characteristic (ROC) curves were used to identify thresholds of fatty acid concentration and fatty acid ratios when ROC area under the curve was ≥0.70. Correct classification rate (CCR, %) was calculated as {[(number of true positives + number of true negatives)/total number tested] × 100}. None of the colostrum fatty acids yielded a sufficiently high area under the curve in ROC analysis for the association with HYK and NEFAH. The following fatty acids and fatty acid ratios were identified for an association with NEFAH (threshold, CCR): C15:0 (≤0.65g/100g, 68.3%); cis-9 C16:1 (≥1.85g/100g, 70.7%); cis-9 C18:1 (≥26g/100g, 69.5%), cis-9 C18:1 to C15:0 ratio (≥45, 69.5%); cis-9 C16:1 to C15:0 (≥2.50, 73.2%). Several fatty acids were associated with HYK (threshold, CCR): C6:0 (≤1.68g/100g, 80.5%), C8:0 (≤0.80g/100g, 80.5%), C10:0 (≤1.6g/100g, 79.3%); C12:0 (≤1.42g/100g, 82.9%); C14:0 (≤6.10g/100g, 84

  20. High bandwidth based on a tapped delay line equalization in visible light communications

    NASA Astrophysics Data System (ADS)

    Zhang, Minglun; Guo, Xujing; Zhu, Hetian; Wang, Chao; Bai, Xiaonan; Zhai, Xiangwen

    2015-08-01

    In the visible light communication, the white LED bandwidth severely limits the transmission rate of information. This paper presents an analog pre-equalization technology to compensate for the bandwidth of white LED. The technology not only can debug according to the actual channel changing, but also avoid the high costs of using FPGA technology. The pre-equalization technology is implemented by an analog circuit of tapped-delay-line, in the circuit we select an appropriate delay line and a digital to analog converter. In our LED visible light communication system, we can achieve a bandwidth of 150MHz which was proved theoretically in the paper.

  1. Public key suppression and recovery using a PANDA ring resonator for high security communication

    NASA Astrophysics Data System (ADS)

    Juleang, Pakorn; Phongsanam, Prapas; Mitatha, Somsak; Yupapin, Preecha P.

    2011-03-01

    An interesting security technique that uses the dark-bright soliton conversion control within the microring resonator is proposed. The obtained outputs for a dark-bright soliton dynamic state can be controlled and used to form the public key suppression for communication security application. However, a good design should be possible to be fabricated; therefore, by using the parameters based on the practical device parameters, the simulation results obtained have shown that the proposed system can indeed be achieved. The public key suppression and public key recovery can be used in a highly secure communication system and has potential applications in optical cryptography.

  2. Overview of the Preliminary Design of the Optical Communication Demonstration and High-Rate Link Facility

    NASA Technical Reports Server (NTRS)

    Sandusky, John V.; Jeganathan, M.; Ortiz, G.; Biswas, A.; Lee, S.; Parker, G.; Liu, B.; Johnson, D.; DePew, J.; Lesh, J. R.

    2000-01-01

    Tlis paper presents an overview of the preliminary design of both the flight and ground systems of the Optical Communication Demonstration and High-Rate Link Facility which will demonstrate optical communication from the International Space Station to ground after its deployment in October 2002. The overview of the preliminary design of the Flight System proceeds by contrasting it with the design of the laboratory-model unit, emphasizing key changes and the rationale behind the design choices. After presenting the preliminary design of the Ground System, the timetable for the construction and deployment of the flight and ground systems is outlined.

  3. Early Communication Development in Infants at High and Low Genetic Risk for Autism Spectrum Disorders: An Examination of Communication Spontaneity

    ERIC Educational Resources Information Center

    Alvarez, Shanna L.

    2013-01-01

    Social communication impairment is one of the key diagnostic features of ASD, with communication deficits being the earliest symptom reported by most parents of children with ASD (Filipek et al., 1999; Landa & Garrett-Meyer, 2006). From differences in babble (Trevarthen & Daniel, 2005; Yirmiya, et al., 2006) and gesture inventories (Landa…

  4. High call volume at poison control centers: identification and implications for communication

    PubMed Central

    CARAVATI, E. M.; LATIMER, S.; REBLIN, M.; BENNETT, H. K. W.; CUMMINS, M. R.; CROUCH, B. I.; ELLINGTON, L.

    2016-01-01

    Context High volume surges in health care are uncommon and unpredictable events. Their impact on health system performance and capacity is difficult to study. Objectives To identify time periods that exhibited very busy conditions at a poison control center and to determine whether cases and communication during high volume call periods are different from cases during low volume periods. Methods Call data from a US poison control center over twelve consecutive months was collected via a call logger and an electronic case database (Toxicall®). Variables evaluated for high call volume conditions were: (1) call duration; (2) number of cases; and (3) number of calls per staff member per 30 minute period. Statistical analyses identified peak periods as busier than 99% of all other 30 minute time periods and low volume periods as slower than 70% of all other 30 minute periods. Case and communication characteristics of high volume and low volume calls were compared using logistic regression. Results A total of 65,364 incoming calls occurred over 12 months. One hundred high call volume and 4885 low call volume 30 minute periods were identified. High volume periods were more common between 1500 and 2300 hours and during the winter months. Coded verbal communication data were evaluated for 42 high volume and 296 low volume calls. The mean (standard deviation) call length of these calls during high volume and low volume periods was 3 minutes 27 seconds (1 minute 46 seconds) and 3 minutes 57 seconds (2 minutes 11 seconds), respectively. Regression analyses revealed a trend for fewer overall verbal statements and fewer staff questions during peak periods, but no other significant differences for staff-caller communication behaviors were found. Conclusion Peak activity for poison center call volume can be identified by statistical modeling. Calls during high volume periods were similar to low volume calls. Communication was more concise yet staff was able to maintain a good

  5. Trigeminal high-frequency stimulation produces short- and long-term modification of reflex blink gain

    PubMed Central

    Ryan, Michael; Kaminer, Jaime; Enmore, Patricia

    2013-01-01

    Reflex blinks provide a model system for investigating motor learning in normal and pathological states. We investigated whether high-frequency stimulation (HFS) of the supraorbital branch of the trigeminal nerve before the R2 blink component (HFS-B) decreases reflex blink gain in alert rats. As with humans (Mao JB, Evinger C. J Neurosci 21: RC151, 2001), HFS-B significantly reduced blink size in the first hour after treatment for rats. Repeated days of HFS-B treatment produced long-term depression of blink circuits. Blink gain decreased exponentially across days, indicating a long-term depression of blink circuits. Additionally, the HFS-B protocol became more effective at depressing blink amplitude across days of treatment. This depression was not habituation, because neither long- nor short-term blink changes occurred when HFS was presented after the R2. To investigate whether gain modifications produced by HFS-B involved cerebellar networks, we trained rats in a delay eyelid conditioning paradigm using HFS-B as the unconditioned stimulus and a tone as the conditioned stimulus. As HFS-B depresses blink circuits and delay conditioning enhances blink circuit activity, occlusion should occur if they share neural networks. Rats acquiring robust eyelid conditioning did not exhibit decreases in blink gain, whereas rats developing low levels of eyelid conditioning exhibited weak, short-term reductions in blink gain. These results suggested that delay eyelid conditioning and long-term HFS-B utilize some of the same cerebellar circuits. The ability of repeated HFS-B treatment to depress trigeminal blink circuit activity long term implied that it may be a useful protocol to reduce hyperexcitable blink circuits that underlie diseases like benign essential blepharospasm. PMID:24285868

  6. Ain't no mountain high enough? Setting high weight loss goals predict effort and short-term weight loss.

    PubMed

    De Vet, Emely; Nelissen, Rob M A; Zeelenberg, Marcel; De Ridder, Denise T D

    2013-05-01

    Although psychological theories outline that it might be beneficial to set more challenging goals, people attempting to lose weight are generally recommended to set modest weight loss goals. The present study explores whether the amount of weight loss individuals strive for is associated with more positive psychological and behavioral outcomes. Hereto, 447 overweight and obese participants trying to lose weight completed two questionnaires with a 2-month interval. Many participants set goals that could be considered unrealistically high. However, higher weight loss goals did not predict dissatisfaction but predicted more effort in the weight loss attempt, as well as more self-reported short-term weight loss when baseline commitment and motivation were controlled for. PMID:22933574

  7. Short-Term Hypocaloric High-Fiber and High-Protein Diet Improves Hepatic Steatosis Assessed by Controlled Attenuation Parameter

    PubMed Central

    Arslanow, Anita; Teutsch, Melanie; Walle, Hardy; Grünhage, Frank; Lammert, Frank; Stokes, Caroline S

    2016-01-01

    OBJECTIVES: Non-alcoholic fatty liver disease is one of the most prevalent liver diseases and increases the risk of fibrosis and cirrhosis. Current standard treatment focuses on lifestyle interventions. The primary aim of this study was to assess the effects of a short-term low-calorie diet on hepatic steatosis, using the controlled attenuation parameter (CAP) as quantitative tool. METHODS: In this prospective observational study, 60 patients with hepatic steatosis were monitored during a hypocaloric high-fiber, high-protein diet containing 1,000 kcal/day. At baseline and after 14 days, we measured hepatic fat contents using CAP during transient elastography, body composition with bioelectrical impedance analysis, and serum liver function tests and lipid profiles using standard clinical–chemical assays. RESULTS: The median age was 56 years (25–78 years); 51.7% were women and median body mass index was 31.9 kg/m2 (22.4–44.8 kg/m2). After 14 days, a significant CAP reduction (14.0% P<0.001) was observed from 295 dB/m (216–400 dB/m) to 266 dB/m (100–353 dB/m). In parallel, body weight decreased by 4.6% (P<0.001), of which 61.9% was body fat. In addition, liver stiffness (P=0.002), γ-GT activities, and serum lipid concentrations decreased (all P<0.001). CONCLUSIONS: This study shows for the first time that non-invasive elastography can be used to monitor rapid effects of dietary treatment for hepatic steatosis. CAP improvements occur after only 14 days on short-term low-calorie diet, together with reductions of body composition parameters, serum lipids, and liver enzymes, pointing to the dynamics of hepatic lipid turnover. PMID:27311064

  8. Joint Access Control Based on Access Ratio and Resource Utilization for High-Speed Railway Communications

    NASA Astrophysics Data System (ADS)

    Zhou, Yuzhe; Ai, Bo

    2015-05-01

    The fast development of high-speed rails makes people's life more and more convenient. However, provisioning of quality of service of multimedia applications for users on the high-speed train is a critical task for wireless communications. Therefore, new solutions are desirable to be found to address this kind of problem. Current researches mainly focus on providing seamless broadband wireless access for high-speed mobile terminals. In this paper, an algorithm to calculate the optimal resource reservation fraction of handovers is proposed. A joint access control scheme for high-speed railway communication handover scenario is proposed. Metrics of access ratio and resource utilization ratio are considered jointly in the analysis and the performance evaluation. Simulation results show that the proposed algorithm and the scheme improve quality of service compared with other conventional schemes.

  9. Improved High-Force Magnetic Tweezers for Stretching and Refolding of Proteins and Short DNA

    PubMed Central

    Chen, Hu; Fu, Hongxia; Zhu, Xiaoying; Cong, Peiwen; Nakamura, Fumihiko; Yan, Jie

    2011-01-01

    Although magnetic tweezers have many unique advantages in terms of specificity, throughput, and force stability, this tool has had limited application on short tethers because accurate measurement of force has been difficult for short tethers under large tension. Here, we report a method that allows us to apply magnetic tweezers to stretch short biomolecules with accurate force calibration over a wide range of up to 100 pN. We demonstrate the use of the method by overstretching of a short DNA and unfolding/refolding a protein of filamin A immunoglobulin domains 1–8. Other potential applications of this method are also discussed. PMID:21244848

  10. Short-term cardiorespiratory adaptation to high altitude in children compared with adults.

    PubMed

    Kriemler, S; Radtke, T; Bürgi, F; Lambrecht, J; Zehnder, M; Brunner-La Rocca, H P

    2016-02-01

    As short-term cardiorespiratory adaptation to high altitude (HA) exposure has not yet been studied in children, we assessed acute mountain sickness (AMS), hypoxic ventilatory response (HVR) at rest and maximal exercise capacity (CPET) at low altitude (LA) and HA in pre-pubertal children and their fathers. Twenty father-child pairs (11 ± 1 years and 44 ± 4 years) were tested at LA (450 m) and HA (3450 m) at days 1, 2, and 3 after fast ascent (HA1/2/3). HVR was measured at rest and CPET was performed on a cycle ergometer. AMS severity was mild to moderate with no differences between generations. HVR was higher in children than adults at LA and increased at HA similarly in both groups. Peak oxygen uptake (VO2 peak) relative to body weight was similar in children and adults at LA and decreased significantly by 20% in both groups at HA; maximal heart rate did not change at HA in children while it decreased by 16% in adults (P < 0.001). Changes in HVR and VO2 peak from LA to HA were correlated among the biological child-father pairs. In conclusion, cardiorespiratory adaptation to altitude seems to be at least partly hereditary. Even though children and their fathers lose similar fractions of aerobic capacity going to high altitude, the mechanisms might be different. PMID:25648726

  11. Facial resurfacing using a high-energy, short-pulse carbon dioxide laser.

    PubMed

    Goodman, G J

    1996-08-01

    Facial skin resurfacing is now possible using short-pulse, high-energy carbon dioxide (CO2) lasers. The laser utilized in this particular paper is the Ultra-pulse CO2 laser. The Ultra-pulse laser represents the first CO2 laser able to vaporize tissue in a single pulse with the use of a large spot size. This laser utilizes the principles of selective photothermolysis. The high-power pulses are completed in less than the thermal relaxation time of skin, estimated to be less than 1 millisecond. This translates into rapid vaporization of tissue with little heat conduction to surrounding tissues. It also should allow a reproducibility of results between practitioners with set parameters not possible with previous CO2 lasers. Clinically, this laser is useful for the removal of skin lesions, and the resurfacing of areas of sun damage, wrinkles and scars. The immediate haemostasis and excellent visibility allows for precise vaporization of abnormal tissue. Rapid and pain-free wound healing is usual. The complication rate would appear to compare very favourably with dermabrasion and chemical peeling techniques. PMID:8771864

  12. High Density Lipoproteins for the Systemic Delivery of short interfering RNA

    PubMed Central

    McMahon, Kaylin M.; Thaxton, C. Shad

    2014-01-01

    Introduction RNA interference (RNAi) is a powerful mechanism for gene silencing with the potential to greatly impact the development of new therapies for many human diseases. Short interfering RNAs (siRNAs) may be the ideal molecules for therapeutic RNAi. However, therapeutic siRNAs face significant challenges that must be overcome prior to widespread clinical use. Many efforts have been made to overcome the hurdles associated with systemic administration of siRNA; however, current approaches are still limited. As such, there is an urgent need to develop new strategies for siRNA delivery that have the potential to impact a broad spectrum of systemic diseases. Areas covered This review focuses on the promise of siRNA therapies and highlights current siRNA delivery methods. With an eye toward new strategies, this review first introduces high density lipoproteins (HDL) and their natural functions, and then transitions into how HDLs may provide significant opportunities as next generation siRNA delivery vehicles. Importantly, this review describes how synthetic HDLs leverage the natural ability of HDL to stabilize and deliver siRNAs. Expert Opinion HDLs are natural nanoparticles that are critical to understanding the systemic delivery of therapeutic nucleic acids, like siRNA. Methods to synthesize biomimetic HDLs are being explored and data demonstrate that this type of delivery vehicle may be highly beneficial for targeted and efficacious systemic delivery of siRNAs. PMID:24313310

  13. Can High-resolution WRF Simulations Be Used for Short-term Forecasting of Lightning?

    NASA Technical Reports Server (NTRS)

    Goodman, S. J.; Lapenta, W.; McCaul, E. W., Jr.; LaCasse, K.; Petersen, W.

    2006-01-01

    A number of research teams have begun to make quasi-operational forecast simulations at high resolution with models such as the Weather Research and Forecast (WRF) model. These model runs have used horizontal meshes of 2-4 km grid spacing, and thus resolved convective storms explicitly. In the light of recent global satellite-based observational studies that reveal robust relationships between total lightning flash rates and integrated amounts of precipitation-size ice hydrometeors in storms, it is natural to inquire about the capabilities of these convection-resolving models in representing the ice hydrometeor fields faithfully. If they do, this might make operational short-term forecasts of lightning activity feasible. We examine high-resolution WRF simulations from several Southeastern cases for which either NLDN or LMA lightning data were available. All the WRF runs use a standard microphysics package that depicts only three ice species, cloud ice, snow and graupel. The realism of the WRF simulations is examined by comparisons with both lightning and radar observations and with additional even higher-resolution cloud-resolving model runs. Preliminary findings are encouraging in that they suggest that WRF often makes convective storms of the proper size in approximately the right location, but they also indicate that higher resolution and better hydrometeor microphysics would be helpful in improving the realism of the updraft strengths, reflectivity and ice hydrometeor fields.

  14. Thermal sterilization of heat-sensitive products using high-temperature short-time sterilization.

    PubMed

    Mann, A; Kiefer, M; Leuenberger, H

    2001-03-01

    High-temperature short-time (HTST) sterilization with a continuous-flow sterilizer, developed for this study, was evaluated. The evaluation was performed with respect to (a) the chemical degradation of two heat-sensitive drugs in HTST range (140-160 degrees C) and (b) the microbiological effect of HTST sterilization. Degradation kinetics of two heat-sensitive drugs showed that a high peak temperature sterilization process resulted in less chemical degradation for the same microbiological effect than a low peak temperature process. Both drugs investigated could be sterilized with acceptable degradation at HTST conditions. For the evaluation of the microbiological effect, Bacillus stearothermophilus ATCC 7953 spores were used as indicator bacteria. Indicator spore kinetics (D(T), z value, k, and E(a)), were determined in the HTST range. A comparison between the Bigelow model (z value concept) and the Arrhenius model, used to describe the temperature coefficient of the microbial inactivation, demonstrated that the Bigelow model is more accurate in prediction of D(T) values in the HTST range. The temperature coefficient decreased with increasing temperature. The influence of Ca(2+) ions and pH value on the heat resistance of the indicator spores, which is known under typical sterilization conditions, did not change under HTST conditions. PMID:11170021

  15. The impact of short duration, high intensity exercise on cardiac troponin release.

    PubMed

    George, Keith P; Grant, Marie Clare; Davies, Bruce; Baker, Julien S

    2016-07-01

    The aim of this study was to assess the appearance of cardiac troponins (cTnI and/or cTnT) after a short bout (30 s) of 'all-out' intense exercise and to determine the stability of any exercise-related cTnI release in response to repeated bouts of high intensity exercise separated by 7 days recovery. Eighteen apparently healthy, physically active, male university students completed two all-out 30 s cycle sprint, separated by 7 days. cTnI, blood lactate and catecholamine concentrations were measured before, immediately after and 24 h after each bout. Cycle performance, heart rate and blood pressure responses to exercise were also recorded. Cycle performance was modestly elevated in the second trial [6·5% increase in peak power output (PPO)]; there was no difference in the cardiovascular, lactate or catecholamine response to the two cycle trials. cTnI was not significantly elevated from baseline through recovery (Trial 1: 0·06 ± 0·04 ng ml(-1) , 0·05 ± 0·04 ng ml(-1) , 0·03 ± 0·02 ng ml(-1) ; Trial 2: 0·02 ± 0·04 ng ml(-1) , 0·04 ± 0·03 ng ml(-1) , 0·05 ± 0·06 ng ml(-1) ) in either trial. Very small within subject changes were not significantly correlated between the two trials (r = 0·06; P>0·05). Subsequently, short duration, high intensity exercise does not elicit a clinically relevant response in cTnI and any small alterations likely reflect the underlying biological variability of cTnI measurement within the participants. PMID:25532821

  16. Crystal accumulation and very high short-circuit currents in rabbit urinary bladder.

    PubMed

    Loo, D D; Diamond, J M

    1985-01-01

    We describe a condition in rabbits characterized by CaCO3 crystal accumulation and very high short-circuit current (Isc) in the urinary bladder. The incidence of the condition was high in rabbits kept for 2 mo or more in the vivarium. The crystal mass in the bladder increased with age or time until it occupied up to one-third of the bladder volume and occasionally aggregated as stones, and the urine attained a sludgy consistency. In animals with sludgy urine, the urine excreted had a crystal content 20 times lower than that of urine contained in the bladder at time of death, implying retention of crystals in the bladder. Kidney stones were not detected in rabbits with bladder crystals, and bladder crystals were absent in rabbits with kidney stones induced experimentally by uremia. In old rabbits with sludgy urine the Isc, a measure of Na+ transport, was up to 46 microA/cm2 and averaged 12 microA/cm2, seven times the Isc of rabbits with nonsludgy urine. The increased Isc was entirely amiloride sensitive. Noise analysis showed it to arise entirely from increased channel density, without change in single-channel current. With one possible exception, we could not find bacterial infection or abnormalities in plasma aldosterone, GFR, or urinary [Na+], [Ca2+], pH, or osmolality that could explain the condition. The exception is that some unidentified component accounting for half the osmolality of nonsludgy urine is absent or at low concentration in sludgy urine. It remains unknown why the condition develops and whether CaCO3 crystals cause high Isc or vice versa or whether both result from a third factor. PMID:3970165

  17. Efficient Service Delivery for High-speed Railway Communications Using MIMO and Access Control Technique

    NASA Astrophysics Data System (ADS)

    Zhou, Yuzhe; Ai, Bo

    2014-07-01

    In order to realize the notion of "anytime, anywhere" communication for high-speed train passengers, the Long Term Evolution for Railway is designed to provide broadband accesses and reliable communications for high-speed train passengers. However, with the increase of train speed, the system is subject to high bit error rate, Doppler frequency shift, and call drops. This paper is trying to solve these problems by employing the Multiple-Input Multiple-Output technique and access control schemes. The goal is to provide higher quality of services such as data rate, reliability, and delay for train passengers. Physical layer performance analysis and access control schemes are proposed in a two-hop model. Handovers and service types are also considered. Simulation results show that proposed models and schemes perform better in improving the quality of services.

  18. Behavior of short silica monolithic columns in high pressure gas chromatography.

    PubMed

    Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antoniali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

    2016-08-19

    In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied. Carrier gas nature was a very significant parameter: on one side, linked to adsorption mechanism for gases like nitrogen and carbon dioxide onto the stationary phase modifying retention and selectivity, on the other side in relation to the minimum theoretical plate height which was as low as 15μm (66 000 platem(-1)) using carbon dioxide as carrier gas. The chromatographic system was then used to separate methane, ethane, ethylene, acetylene, propane, cyclopropane, and butane in less than 30s. PMID:27432790

  19. Extended high-angular-frequency analysis of turbulence effects on short-exposure imaging

    NASA Astrophysics Data System (ADS)

    Tofsted, David H.

    2014-04-01

    An improved analysis of optical turbulence effects on short-exposure passive (SE) imaging is described, resulting in a new analytic expression for the SE modulation transfer function (MTF). This analysis expands on a 2011 study that examined characteristics of a tilt-phase component discovered in the standard theory of SE turbulence effects characterization. The analysis introduces an improved integration technique and a reformulated phase structure function, facilitating computation of a 38,007 element database of MTF results at low- to high-angular frequencies covering a wide range of diffraction and turbulence conditions. Analysis of this database is described, yielding a new analytic SE MTF, accurate to a root-mean-square error of 0.000218 versus the database. Comparisons show that the new expression is well correlated to an alternative computationally intensive method, and it is a factor 29 to 64 improvement over prior analytic expressions. Limits of applicability of the approach for incoherent imaging are also discussed. The low-computational cost of the new method is suitable for systems performance modeling of turbulence impacts, including path-varying turbulence scenarios.

  20. Evidence for short range corelations from high Q{sup 2} (e,e{prime}) reactions

    SciTech Connect

    Strikman, M.I.; Frankfurt, L.L.; Sargayan, M.M.

    1994-04-01

    For many years now short-range correlations (SRC) in nuclei have been considered as an essential feature of the nuclear wave function. At high energy (e,e{prime}) reactions, where Q{sup 2} > 1 (GeV/c){sup 2}, x = Q{sup 2}/2mq{sub o} > 1 and 1 GeV > q{sub o}> 300 {approximately} 400 MeV the scattering from low momentum nucleons is kinematically suppressed and there the evidence of SRC expected to be more prominent. These reactions have been intensively investigated during the last decade or so at SLAC on both light and heavy nuclei. The above kinematics allows one to compute the cross section through the processes local in space. To explain this the authors analyse the representation of the cross section as a Fourier transform of the commutator of electromagnetic currents and see that the major contribution in the cross section is given by the region of integration.

  1. Short telomeres and high telomerase activity in T-cell prolymphocytic leukemia.

    PubMed

    Röth, A; Dürig, J; Himmelreich, H; Bug, S; Siebert, R; Dührsen, U; Lansdorp, P M; Baerlocher, G M

    2007-12-01

    To test the role of telomere biology in T-cell prolymphocytic leukemia (T-PLL), a rare aggressive disease characterized by the expansion of a T-cell clone derived from immuno-competent post-thymic T-lymphocytes, we analyzed telomere length and telomerase activity in subsets of peripheral blood leukocytes from 11 newly diagnosed or relapsed patients with sporadic T-PLL. Telomere length values of the leukemic T cells (mean+/-s.d.: 1.53+/-0.65 kb) were all below the 1st percentile of telomere length values observed in T cells from healthy age-matched controls whereas telomere length of normal T- and B cells fell between the 1st and 99th percentile of the normal distribution. Leukemic T cells exhibited high levels of telomerase and were sensitive to the telomerase inhibitor BIBR1532 at doses that showed no effect on normal, unstimulated T cells. Targeting the short telomeres and telomerase activity in T-PLL seems an attractive strategy for the future treatment of this devastating disease. PMID:17898784

  2. Proton acceleration from high-contrast short pulse lasers interacting with sub-micron thin foils

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; McGuffey, C.; Thomas, A. G. R.; Krushelnick, K.; Beg, F. N.

    2016-02-01

    A theoretical study complemented with published experimental data of proton acceleration from sub-micron (thickness < 1 μm) foils irradiated by ultra-high contrast ( >1010 ) short pulse lasers is presented. The underlying physics issues pertinent to proton acceleration are addressed using two-dimensional particle-in-cell simulations. For laser energy ɛ≤4 J (intensity I ≤5 ×1020 W/cm 2 ), simulation predictions agree with experimental data, both exhibiting scaling superior to Target Normal Sheath Acceleration's model. Anomalous behavior was observed for ɛ>4 J ( I >5 ×1020 W/cm 2 ), for which the measured maximum proton energies were much lower than predicted by scaling and these simulations. This unexpected behavior could not be explained within the frame of the model, and we conjecture that pre-pulses preceding the main pulse by picoseconds may be responsible. If technological issues can be resolved, energetic proton beams could be generated for a wide range of applications such as nuclear physics, radiography, and medical science.

  3. High-fidelity rotor gap measurements in a short-duration turbine rig

    NASA Astrophysics Data System (ADS)

    Lavagnoli, Sergio; Paniagua, Guillermo; Tulkens, Maxime; Steiner, Alexander

    2012-02-01

    The distance between the tip of rotating airfoils and the stationary casing, i.e., the tip clearance, is a vital parameter to characterize turbomachinery performance. The larger the tip clearance, the lower the turbine efficiency due to the increased loss associated with the hot jet flowing through the gap without generating work. Following the increasing demands in efficiency, these small clearances must be surveyed to avoid mechanical rubbing. The appropriate design of control systems to adjust these small clearances requires a constant monitoring during the whole engine envelope. This paper describes the complete implementation of a high-frequency capacitive sensor on the shroud of a large transonic turbine stage. The presented system and data analysis procedure allow the accurate measurement of the tip clearance of each rotating airfoil. The measurement system performances are first assessed in a simplified test bench and uncertainty analysis is provided. The technique is demonstrated in an aero-propulsion turbine, tested in a short duration rig. The turbine facility has running times of less than 0.5 s, characterized by temperature and rotor speed transients, which requires particular in-situ sensor calibrations. Extensive running tip clearance measurements of the large aero-engine turbine stage validate the system concept and design.

  4. Evaluation of high-temperature and short-time sterilization of injection ampules by microwave heating.

    PubMed

    Sasaki, K; Honda, W; Miyake, Y

    1998-01-01

    The high-temperature and short-time sterilization by microwave heating with a continuous microwave sterilizer (MWS) was evaluated. The evaluation were performed with respect to: [1] lethal effect against microorganisms corresponding to F-value, and [2] reliability of MWS sterilization process. Bacillus stearothermophilus ATCC 7953 spores were used as the biological indicator and the heat-resistance of spores was evaluated with conventional heating method (121-129 degrees C). In MWS sterilization (125-135 degrees C), the actual lethal effect against B. stearothermophilus spores was almost in agreement with the F-value and the survival curve against the F-value was quite consistent with that for the autoclave. These results suggest that the actual lethal effect could be estimated by the F-value with heat-resistance parameters of spores from lower than actual temperatures and that there was no nonthermal effect of the microwave on B. stearothermophilus spores. The reliability of sterilization with the MWS was confirmed using more than 25,000 test ampules containing biological indicators. All biological indicators were killed, thus the present study shows that the MWS was completely reliable for all ampules. PMID:9542408

  5. Short Range Photoassociation of Rb2 by a high power fiber laser

    NASA Astrophysics Data System (ADS)

    Passagem, Henry; Rodriguez, Ricardo; Ventura, Paulo; Bouloufa, Nadia; Dulieu, Olivier; Marcassa, Luis

    2016-05-01

    Photoassociation has been studied using cold trapped atomic samples for the last 20 years. Due to poor Franck-Condon overlap, a free-to-bound transition followed by spontaneous decay results in a small production of electronic ground state molecules. If the photoassociation is done at short range, deeply bound ground state molecules can be formed. Optical pumping schemes can be used to populate a single state. In our experiment, we have performed trap loss spectroscopy on trapped 85 Rb atoms in a MOT using a high power fiber laser. Our single mode fiber laser (linewidth < 1 MHz) produces about 50 W, which can be tuned in the 1060-1070 nm range. Two vibrational bound states of the 0u+ potential were observed (ν = 137 and 138). The frequency positions as well as the rotational constants of these states are in good agreement with theoretical predictions. We have also measured the lifetime of a crossed optical dipole trap using such fiber laser. The lifetime on resonance is shorter than off resonance as expected. A simple theoretical model indicates that the molecules decay to deeply bound vibrational levels in the ground state. This work was supported by Fapesp and INCT-IQ.

  6. Effect of high density on the short term Calomys musculinus spacing behaviour: A fencing experiment

    NASA Astrophysics Data System (ADS)

    Sommaro, Lucía V.; Steinmann, Andrea R.; Chiappero, Marina B.; Priotto, José W.

    2010-05-01

    We studied the short term spacing behavioural responses of corn mice ( Calomys musculinus) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2007 breeding season. The goal of this research was to test the hypothesis that spacing behaviour only operates among C. musculinus adult females. We estimated 207 home ranges to study: 1) the home range size and the overlap degree of adult males and females in relation to population density; 2) the settlement distances of juveniles to the centre of activity of their mothers and the home range overlap proportion between them and their mothers in relation to population density. We found that home range size and overlap degree in C. musculinus adults were determined by sex and density. At high population density males had significant smaller and more exclusive home ranges, and this might reflect induced territoriality derived from social restrictions. Female home range sizes remained similar irrespective of population density, and they kept exclusive home ranges in both control and experimental enclosures. Thus, females maintained their territories independent of the population density values. The settlement distances of juveniles from their mothers and the overlap proportion between them and their mothers were independent of population density. We conclude that spacing behaviour only operates among C. musculinus adult females and it could have a role in regulating population abundances limiting the number of females that acquire breeding spaces.

  7. High-speed pulsed mixing in a short distance with high-frequency switching of pumping from three inlets

    NASA Astrophysics Data System (ADS)

    Sugano, K.; Nakata, A.; Tsuchiya, T.; Tabata, O.

    2015-08-01

    In this study, we propose a mixing method using alternate pulsed flows from three inlets with flow direction control. In conventional pulsed mixing, a residual flow near the sidewalls inhibits the rapid mixing of two solutions at high switching frequency. In this study, we addressed this issue in order to perform rapid mixing in a short distance with a low Reynolds number. We fabricated a microfluidic mixing device consisting of a cross-shaped mixing channel with three inlet microchannels and three valveless micropumps. In conventional T-shaped or Y-shaped mixing channels, a residual flow is observed because of the incomplete switching of solutions. The three inlet configuration enabled us to split the residual flow at a switching frequency of pumping of up to 200 Hz, thus resulting in rapid mixing. Furthermore, by controlling the flow direction at the confluent area using the reverse flow of the micropump, the mixing speed was dramatically increased because of the complete switching of the two solutions. As a result, we achieved the mixing time of 3.6 ms and the mixing length of 20.7 µm, which were necessary to achieve a 90% mixing ratio at a high micropump switching frequency of 400 Hz and reverse flow ratio of 1/4.

  8. A High-Speed Optical Modem Communication System for CORK Seafloor Observatories

    NASA Astrophysics Data System (ADS)

    Farr, N.; Tivey, M.; Ware, J.; Pontbriand, C.; Pelletier, L. P.

    2014-12-01

    High-speed communications underwater is an increasing requirement for data intensive seafloor sensors. Acoustic modems provide dependable long-range communications underwater, but data rates are limited to <57Kbps. Free-water optical modems (OMs) offer high data rate, 10Mbps communications over a range of 200 m - a distance for ROVs, AUVs or wire-lowered packages to communicate without the need to directly plug-in or retrieve the instrument. Over the past 4 years, we have demonstrated the functionality and utility of OM technology using a CORK borehole observatory as a test case. A CORK represents all of the basic components required for a seafloor observatory: a stable environment for long-term continuous measurements of earth and ocean phenomena, access to a unique environment below the seafloor and a standard communication interface. The CORK-OM features a high-bandwidth, low-latency optical system based on LED emitters and PMT receivers and an acoustic command and control system. OM tests established a communication link from 20 to 200 meters range at rates of 1, 5 and 10 Mbps with no bit errors. The seafloor OM was plugged into the CORK's existing underwater wet mateable connector and provided additional power to the CORK to boost the data rate to 1 Hz from the normal 1 minute sample period. To communicate with the seafloor CORK-OM, a number of different modalities were used. One method was an OM mounted to a CTD frame on a lowered wire from a ship with an SDSL link over the conducting wire. Other methods utilized OMs mounted to both ROV Jason and submersible Alvin. We deployed OMs at two CORKs in 2012 in the northeast pacific at sites 857D and 1025C. The CORKs were visited in 2013 by a vessel of opportunity to download data and were put into sleep mode. The CORKs were revisited in 2014, woken up and successfully interrogated for data. ALVIN retrieved the CORK-OMs for corrosion, biofouling and battery performance assessment. We also performed tests of a next

  9. Short time interval for condensation of high-temperature silicates in the solar accretion disk.

    PubMed

    Luu, Tu-Han; Young, Edward D; Gounelle, Matthieu; Chaussidon, Marc

    2015-02-01

    Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived (26)Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a (26)Al isochron with (26)Al/(27)Al = 1.2(±0.2) × 10(-5) for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule (26)Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial ((26)Al/(27)Al) ≥ 1.2 × 10(-5). In addition, mineral (26)Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule (26)Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate. PMID:25605942

  10. Autonomic Function Predicts Fitness Response to Short-Term High-Intensity Interval Training.

    PubMed

    Kiviniemi, A M; Tulppo, M P; Eskelinen, J J; Savolainen, A M; Kapanen, J; Heinonen, I H A; Hautala, A J; Hannukainen, J C; Kalliokoski, K K

    2015-11-01

    We tested the hypothesis that baseline cardiac autonomic function and its acute response to all-out interval exercise explains individual fitness responses to high-intensity interval training (HIT). Healthy middle-aged sedentary men performed HIT (n=12, 4-6×30 s of all-out cycling efforts with 4-min recovery) or aerobic training (AET, n=9, 40-60 min at 60% of peak workload in exercise test [Loadpeak]), comprising 6 sessions within 2 weeks. Low (LF) and high frequency (HF) power of R-R interval oscillation were analyzed from data recorded at supine and standing position (5+5 min) every morning during the intervention. A significant training effect (p< 0.001), without a training*group interaction, was observed in Loadpeak and peak oxygen consumption (VO2peak). Pre-training supine LF/HF ratio, an estimate of sympathovagal balance, correlated with training outcome in Loadpeak (Spearman's rho [rs]=-0.74, p=0.006) and VO2peak (rs=- 0.59, p=0.042) in the HIT but not the AET group. Also, the mean change in the standing LF/HF ratio in the morning after an acute HIT exercise during the 1(st) week of intervention correlated with training response in Loadpeak (rs=- 0.68, p=0.014) and VO2peak (rs=-0.60, p=0.039) with HIT but not with AET. In conclusion, pre-training cardiac sympathovagal balance and its initial alterations in response to acute HIT exercise were related to fitness responses to short-term HIT. PMID:26140689

  11. Measurement of short lifetimes in highly-charged ions using a two-foil target

    SciTech Connect

    Berry, H.G.; Dunford, R.W.; Gemmell, D.S.

    1995-08-01

    One of the frontiers in the study of the atomic physics of highly-charged ions is the measurement of lifetimes in the 100 fs to 10 ps regime. The standard technique for measuring lifetimes of states in highly-charged ions is the beam-foil time-of-flight method in which the intensity of an emission line is monitored as a function of the separation between the exciting foil and the portion of the beam being viewed by the detector. This method becomes increasingly difficult as the decay lengths of the states of interest become shorter. At a typical beam velocity of 10% of the speed of light, the beam travels 30 microns in a picosecond. The standard beam-foil time-of-flight method necessitates observation of the decay radiation within one or two decay lengths from the foil while preventing the detectors from observing the beam spot at the foil. For short-lived states this requires tight collimation of the detector with a resulting loss in solid angle. We are developing a method for measuring ultrashort atomic lifetimes utilizing a two-foil target. As a specific case to demonstrate the feasibility of our method, we are studying the decay of the 2 {sup 3}P{sub 2} level in helium-like Kr{sup 34+}. This level has a calculated lifetime of 9.5 ps which corresponds to a decay length of 380 {mu}m. For krypton, theory predicts that 90% of the 2 {sup 3}P{sub 2} states decay via M2 radiation to the ground state. A measurement of the lifetime of this state would contribute to an important current problem which concerns the understanding of atomic structure when both electron correlations and relativistic effects are simultaneously important.

  12. Short time interval for condensation of high-temperature silicates in the solar accretion disk

    PubMed Central

    Luu, Tu-Han; Young, Edward D.; Gounelle, Matthieu; Chaussidon, Marc

    2015-01-01

    Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived 26Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a 26Al isochron with 26Al/27Al = 1.2(±0.2) × 10−5 for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule 26Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial (26Al/27Al) ≥ 1.2 × 10−5. In addition, mineral 26Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule 26Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate. PMID:25605942

  13. Short spatial filters with spherical lenses for high-power pulsed lasers

    SciTech Connect

    Burdonov, K F; Soloviev, A A; Shaikin, A A; Potemkin, A K; Egorov, A S

    2013-11-30

    We report possible employment of short spatial filters based on spherical lenses in a pulsed laser source (neodymium glass, 300 J, 1 ns). The influence of the spherical aberration on the quality of output radiation and coefficient of conversion to the second harmonics is studied. The ultra-short aberration spatial filter of length 1.9 m with an aperture of 122 mm is experimentally tested. A considerable shortening of multi-cascade pump lasers for modern petawatt laser systems is demonstrated by the employment of short spatial filters without expensive aspherical optics. (elements of laser systems)

  14. The High-Performance Computing and Communications program, the national information infrastructure and health care.

    PubMed

    Lindberg, D A; Humphreys, B L

    1995-01-01

    The High-Performance Computing and Communications (HPCC) program is a multiagency federal effort to advance the state of computing and communications and to provide the technologic platform on which the National Information Infrastructure (NII) can be built. The HPCC program supports the development of high-speed computers, high-speed telecommunications, related software and algorithms, education and training, and information infrastructure technology and applications. The vision of the NII is to extend access to high-performance computing and communications to virtually every U.S. citizen so that the technology can be used to improve the civil infrastructure, lifelong learning, energy management, health care, etc. Development of the NII will require resolution of complex economic and social issues, including information privacy. Health-related applications supported under the HPCC program and NII initiatives include connection of health care institutions to the Internet; enhanced access to gene sequence data; the "Visible Human" Project; and test-bed projects in telemedicine, electronic patient records, shared informatics tool development, and image systems. PMID:7614116

  15. Consensus Statement for the Management and Communication of High Risk Laboratory Results

    PubMed Central

    Campbell, Craig; Caldwell, Grahame; Coates, Penelope; Flatman, Robert; Georgiou, Andrew; Horvath, Andrea Rita; Lam, Que; Schneider, Hans

    2015-01-01

    Ineffective test follow-up is a major source of harm for patients around the world. Unreliable communication from medical laboratories (henceforth termed ‘laboratories’) to clinicians of results that represent critical or significant risk to patients (collectively termed ‘high risk results’) is a contributing factor to this problem. Throughout Australasia, management practices for such results vary considerably. The recommendations presented in this document are based on best practice derived from the published literature and follow consultation with a wide range of stakeholders. These recommendations were created to harmonise Australasian practices by guiding laboratories in the design and implementation of safe and effective communication procedures for managing high risk results which require timely notification. PMID:26900189

  16. High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link

    NASA Technical Reports Server (NTRS)

    Yang, Guangning; Lu, Wei; Krainak, Michael; Sun, Xiaoli

    2016-01-01

    We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.

  17. ScalaTrace: Scalable Compression and Replay of Communication Traces for High Performance Computing

    SciTech Connect

    Noeth, M; Ratn, P; Mueller, F; Schulz, M; de Supinski, B R

    2008-05-16

    Characterizing the communication behavior of large-scale applications is a difficult and costly task due to code/system complexity and long execution times. While many tools to study this behavior have been developed, these approaches either aggregate information in a lossy way through high-level statistics or produce huge trace files that are hard to handle. We contribute an approach that provides orders of magnitude smaller, if not near-constant size, communication traces regardless of the number of nodes while preserving structural information. We introduce intra- and inter-node compression techniques of MPI events that are capable of extracting an application's communication structure. We further present a replay mechanism for the traces generated by our approach and discuss results of our implementation for BlueGene/L. Given this novel capability, we discuss its impact on communication tuning and beyond. To the best of our knowledge, such a concise representation of MPI traces in a scalable manner combined with deterministic MPI call replay are without any precedent.

  18. Low noise, free running, high rate photon counting for space communication and ranging

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Krainak, Michael A.; Yang, Guangning; Sun, Xiaoli; Merritt, Scott

    2016-05-01

    communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies (>50%) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their space communication and ranging performances using both the 2 detected photon threshold and coincidence methods.

  19. Highly optimized fourth-order short-time approximation for pathintegrals

    SciTech Connect

    Predescu, Cristian

    2006-10-01

    We derive a fourth-order short-time approximation for use in imaginary-time path-integral simulations. The short-time approximation converges for all continuous and bounded from below potentials, attains quartic order of convergence for sufficiently smooth potentials, and utilizes statistically independent random variables for its construction. These properties recommend the approximation as a natural replacement of the trapezoidal Trotter-Suzuki approximation for physical systems with continuous distributions.

  20. Highly optimized fourth-order short-time approximation for path integrals.

    PubMed

    Predescu, Cristian

    2006-01-19

    We derive a fourth-order short-time approximation for use in imaginary-time path-integral simulations. The short-time approximation converges for all continuous and bounded-from-below potentials, attains quartic order of convergence for sufficiently smooth potentials, and utilizes statistically independent random variables for its construction. These properties recommend the approximation as a natural replacement of the trapezoidal Trotter-Suzuki approximation for physical systems with continuous distributions. PMID:16471584

  1. Innovative, High-Pressure, Cryogenic Control Valve: Short Face-to-Face, Reduced Cost

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A control valve that can throttle high-pressure cryogenic fluid embodies several design features that distinguish it over conventional valves designed for similar applications. Field and design engineers worked together to create a valve that would simplify installation, trim changes, and maintenance, thus reducing overall cost. The seals and plug stem packing were designed to perform optimally in cryogenic temperature ranges. Unlike conventional high-pressure cryogenic valves, the trim size can be changed independent of the body. The design feature that provides flexibility for changing the trim is a split body. The body is divided into an upper and a lower section with the seat ring sandwiched in between. In order to maintain the plug stem packing at an acceptable sealing temperature during cryogenic service, heat-exchanging fins were added to the upper body section. The body is made of stainless steel. The seat ring is made of a nickel-based alloy having a coefficient of thermal expansion less than that of the body material. Consequently, when the interior of the valve is cooled cryogenically, the body surrounding the seat ring contracts more than the seat ring. This feature prevents external leakage at the body-seat joint. The seat ring has been machined to have small, raised-face sealing surfaces on both sides of the seal groove. These sealing surfaces concentrate the body bolt load over a small area, thereby preventing external leakage. The design of the body bolt circle is different from that of conventional highpressure control valves. Half of the bolts clamp the split body together from the top, and half from the bottom side. This bolt-circle design allows a short, clean flow path, which minimizes frictional flow losses. This bolt-circle design also makes it possible to shorten the face-toface length of the valve, which is 25.5 in. (65 cm). In contrast, a conventional, high-pressure control valve face-to-face dimension may be greater than 40 in. (>1 m

  2. Verification & Validation of High-Order Short-Characteristics-Based Deterministic Transport Methodology on Unstructured Grids

    SciTech Connect

    Azmy, Yousry; Wang, Yaqi

    2013-12-20

    The research team has developed a practical, high-order, discrete-ordinates, short characteristics neutron transport code for three-dimensional configurations represented on unstructured tetrahedral grids that can be used for realistic reactor physics applications at both the assembly and core levels. This project will perform a comprehensive verification and validation of this new computational tool against both a continuous-energy Monte Carlo simulation (e.g. MCNP) and experimentally measured data, an essential prerequisite for its deployment in reactor core modeling. Verification is divided into three phases. The team will first conduct spatial mesh and expansion order refinement studies to monitor convergence of the numerical solution to reference solutions. This is quantified by convergence rates that are based on integral error norms computed from the cell-by-cell difference between the code’s numerical solution and its reference counterpart. The latter is either analytic or very fine- mesh numerical solutions from independent computational tools. For the second phase, the team will create a suite of code-independent benchmark configurations to enable testing the theoretical order of accuracy of any particular discretization of the discrete ordinates approximation of the transport equation. For each tested case (i.e. mesh and spatial approximation order), researchers will execute the code and compare the resulting numerical solution to the exact solution on a per cell basis to determine the distribution of the numerical error. The final activity comprises a comparison to continuous-energy Monte Carlo solutions for zero-power critical configuration measurements at Idaho National Laboratory’s Advanced Test Reactor (ATR). Results of this comparison will allow the investigators to distinguish between modeling errors and the above-listed discretization errors introduced by the deterministic method, and to separate the sources of uncertainty.

  3. Short range structure of hadron and nuclear wave functions at high x

    SciTech Connect

    Hoyer, P.; Brodsky, S.J.

    1990-11-01

    We discuss the short-range structure of hadronic and nuclear wave functions expected in QCD. In addition to the extrinsic'' contributions associated with radiation from single partons, there is an intrinsic'' hardness of the high-mass fluctuations of the wave function due to the spatial overlap of two or more partons. We argue that intrinsically-hard partons, having large mass and/or large transverse momentum, will dominate in the region of large Feynman x{sub F}. Their rescattering in nuclear targets is expected to be larger than for extrinsically-hard partons, leading to a suppressed production cross section for hadrons scattering on heavy nuclei. Experimental evidence for this exists for open chars. J/{psi}, and {gamma} production at large x{sub F}. The effects of intrinsic hardness may be particularly striking in nuclear wave functions, where the overlap of partons belonging to different nucleons can give rise to cumulative (x > 1) phenomena. The data on backward cumulative particle production from nuclei supports the existence of an intrinsically-hard component in nuclear wave functions. Partons at large x{sub F} may also be associated with the enhanced subthreshold production of particles observed in hadron-nucleus and nucleus-nucleus collisions. We discuss the evidence for anomalies in the large angle pp {yields} pp cross section near the charm threshold. Arguments are presented that chromium states may bind to nuclei through the QCD Van der Waals force. This would lead to a striking signal in charm production near threshold. 49 refs., 7 figs.

  4. Enhancing Short-Term Recovery After High-Intensity Anaerobic Exercise.

    PubMed

    Al-Nawaiseh, Ali M; Pritchett, Robert C; Bishop, Philip A

    2016-02-01

    This study examined the effects of antioxidant vitamins, ibuprofen, cold water submersion, and whey protein administered simultaneously on short-term recovery. Competitive athletes (n = 22) performed the protocol in 2 occasions (treatment and control) separated by 15 days in counterbalanced crossover design. Each occasion consisted of morning and afternoon sessions (AM and PM). In each session, participants performed 2 bouts of high-intensity anaerobic cycling separated by 30 minutes of rest. Each bout consisted of 3 Wingate tests (3 × 30-second Wingate tests) with 3 minutes of active recovery in between. Power output, rated perceived exertion (RPE), and pain scores were averaged and compared between the 2 sessions (AM vs. PM) and between the treatment vs. control (4 bouts). Creatine kinase (CK) levels were also measured 24 hours after the AM bout. Power output, CK, muscle soreness, and RPE were measured as recovery indices. Creatine kinase increased (p < 0.001) in both treatment and control 24 hours after the AM session. Performance results in the PM session for treatment/control were 832.5 ± 198.7/813.3 ± 187.6 W for peak power (PP), and 497.85 ± 120.7/486.1 ± 115 W for mean power (MP). Treatment was effective in maintaining MP (p = 0.034) in the PM sessions, but there was no significant effect of treatment on PP (p = 0.193), CK (p = 0.08), pain (p = 0.12), or RPE (p = 0.45). Treatment was helpful in protecting performance, but this was apparently not due to reduced muscle soreness or damage. PMID:26815173

  5. High-intensity exercise of short duration alters bovine bone density and shape.

    PubMed

    Hiney, K M; Nielsen, B D; Rosenstein, D; Orth, M W; Marks, B P

    2004-06-01

    The ability of short-duration high-intensity exercise to stimulate bone formation in confinement was investigated using immature Holstein bull calves as a model. Eighteen bull calves, 8 wk of age, were assigned to one of three treatment groups: 1) group-housed (GR, which served as a control), 2) confined with no exercise (CF), or 3) confined with exercise (EX). The exercise protocol consisted of running 50 m on a concrete surface once daily, 5 d/wk. Confined calves remained stalled for the 42-d duration of the trial. Blood samples were taken to analyze concentrations of osteocalcin and deoxypyridinoline, markers of bone formation and resorption. At the completion of the trial, calves were humanely killed, and both forelegs were collected. The fused third and fourth metacarpal bone was scanned using computed tomography for determination of cross-sectional geometry and bone mineral density. Three-point bending tests to failure were performed on metacarpal bones. The exercise protocol resulted in the formation of a rounder bone in EX as well as in increased dorsal cortex thickness compared with those in the GR and CF. The exercised calves had a significantly smaller medullary cavity than CF and GR (P < 0.01) and a larger percentage of cortical bone area than CF (P < 0.01). Dorsal, palmar, and total bone mineral density was greater in EX than in CF (P < 0.05), and palmar and total bone mineral densities were greater (P < 0.05) in EX than in GR. There was a trend for the bones of EX to have a higher fracture force than CF (P < 0.10). Osteocalcin concentrations normalized from d 0 were higher in EX than CF (P < 0.05). Therefore, the exercise protocol altered bone shape and seemed to increase bone formation comparison with the stalled and group-housed calves. PMID:15216986

  6. High-energy neutrinos from the gravitational wave event GW150914 possibly associated with a short gamma-ray burst

    NASA Astrophysics Data System (ADS)

    Moharana, Reetanjali; Razzaque, Soebur; Gupta, Nayantara; Mészáros, Peter

    2016-06-01

    High-energy neutrinos (HEN) and gravitational waves (GW) can probe astrophysical sources in addition to electromagnetic observations. Multimessenger studies can reveal the nature of the sources, which may not be discerned from one type of signal alone. We discuss HEN emission in connection with the Advanced Laser Interferometer Gravitational-Wave Observatory event GW150914, which could be associated with a short gamma-ray burst detected by the Fermi Gamma-Ray Burst Monitor 0.4 s after the GW event and within localization uncertainty of the GW event. We calculate HEN flux from this short gamma-ray burst, GW150914-GBM, and show that nondetection of a high-energy starting event by the IceCube Neutrino Observatory can constrain the total isotropic-equivalent jet energy of this short burst to be less than 3 ×1052 erg .

  7. Development of data communication system with ultra high frequency radio wave for implantable artificial hearts.

    PubMed

    Tsujimura, Shinichi; Yamagishi, Hiroto; Sankai, Yoshiyuki

    2009-01-01

    In order to minimize infection risks of patients with artificial hearts, wireless data transmission methods with electromagnetic induction or light have been developed. However, these methods tend to become difficult to transmit data if the external data transmission unit moves from its proper position. To resolve this serious problem, the purpose of this study is to develop a prototype wireless data communication system with ultra high frequency radio wave and confirm its performance. Due to its high-speed communication rate, low power consumption, high tolerance to electromagnetic disturbances, and secure wireless communication, we adopted Bluetooth radio wave technology for our system. The system consists of an internal data transmission unit and an external data transmission unit (53 by 64 by 16 mm, each), and each has a Bluetooth module (radio field intensity: 4 dBm, receiver sensitivity: -80 dBm). The internal unit also has a micro controller with an 8-channel 10-bit A/D converter, and the external unit also has a RS-232C converter. We experimented with the internal unit implanted into pig meat, and carried out data transmission tests to evaluate the performance of this system in tissue thickness of up to 3 mm. As a result, data transfer speeds of about 20 kbps were achieved within the communication distance of 10 m. In conclusion, we confirmed that the system can wirelessly transmit the data from the inside of the body to the outside, and it promises to resolve unstable data transmission due to accidental movements of an external data transmission unit. PMID:19964616

  8. Short-Wave Diathermy Pretreatment and Inflammatory Myokine Response After High-Intensity Eccentric Exercise

    PubMed Central

    Vardiman, John P.; Moodie, Nicole; Siedlik, Jacob A.; Kudrna, Rebecca A.; Graham, Zachary; Gallagher, Philip

    2015-01-01

    Context Various modalities have been used to pretreat skeletal muscle to attenuate inflammation. Objective To determine the effects of short-wave diathermy (SWD) preheating treatment on inflammation and stress markers after eccentric exercise. Design Controlled laboratory study. Setting University laboratory setting. Patients or Other Participants Fifteen male (age = 22 ± 4.9 years, height = 179.75 ± 9.56 cm, mass = 82.22 ± 12.67 kg) college-aged students. Intervention(s) Seven participants were selected randomly to receive 40 minutes of SWD heat treatment (HT), and 8 participants served as the control (CON) group and rested without SWD. Both groups completed 7 sets of 10 repetitions of a high-intensity eccentric exercise protocol (EEP) at 120% of the 1-repetition maximum (1-RM) leg extension. Main Outcome Measure(s) We biopsied muscles on days 1, 3 (24 hours post-EEP), and 4 (48 hours post-EEP) and collected blood samples on days 1, 2 (4 hours post-EEP), 3, and 4. We determined 1-RM on day 2 (24 hours post-SWD) and measured 1-RM on days 3 and 4. We analyzed the muscle samples for interleukin 6 (IL-6), tumor necrosis factor α, and heat shock protein 70 and the blood for serum creatine kinase. Results We found a group × time interaction for intramuscular IL-6 levels after SWD (F2,26 = 7.13, P = .003). The IL-6 decreased in HT (F1,6 = 17.8, P = .006), whereas CON showed no change (P > .05). We found a group × time interaction for tumor necrosis factor α levels (F2,26 = 3.71, P = .04), which increased in CON (F2,14 = 7.16, P = .007), but saw no changes for HT (P > .05). No group × time interactions were noted for 1-RM, heat shock protein 70, or creatine kinase (P > .05). Conclusions The SWD preheating treatment provided a treatment effect for intramuscular inflammatory myokines induced through high-intensity eccentric exercise but did not affect other factors associated with intense exercise and inflammation. PMID:25844857

  9. NASA high performance computing, communications, image processing, and data visualization-potential applications to medicine.

    PubMed

    Kukkonen, C A

    1995-06-01

    High-speed information processing technologies being developed and applied by the Jet Propulsion Laboratory for NASA and Department of Defense mission needs have potential dual-uses in telemedicine and other medical applications. Fiber optic ground networks connected with microwave satellite links allow NASA to communicate with its astronauts in Earth orbit or on the moon, and with its deep space probes billions of miles away. These networks monitor the health of astronauts and or robotic spacecraft. Similar communications technology will also allow patients to communicate with doctors anywhere on Earth. NASA space missions have science as a major objective. Science sensors have become so sophisticated that they can take more data than our scientists can analyze by hand. High performance computers--workstations, supercomputer and massively parallel computers are being used to transform this data into knowledge. This is done using image processing, data visualization and other techniques to present the data--one's and zero's in forms that a human analyst can readily relate to and understand. Medical sensors have also explored in the in data output--witness CT scans, MRI, and ultrasound. This data must be presented in visual form and computers will allow routine combination of many two dimensional MRI images into three dimensional reconstructions of organs that then can be fully examined by physicians. Emerging technologies such as neural networks that are being "trained" to detect craters on planets or incoming missiles amongst decoys can be used to identify microcalcification in mammograms. PMID:7643022

  10. In-situ short circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Rouillard, Jean; Rouillard, Roger; Shiota, Toshimi; Trice, Jennifer L.

    2000-01-01

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  11. In-situ short-circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Rouillard, Jean; Rouillard, Roger; Shiota, Toshimi; Trice, Jennifer L.

    2003-04-15

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  12. Lottery games and risky technologies: communications about low-probability/high-consequence events

    SciTech Connect

    Mumpower, J.L.

    1988-06-01

    There are strong structural similarities between risks from technological hazards and big-purse state lottery games. Risks from technological hazards are often described as low-probability, high-consequence negative events. State lotteries could be equally well characterized as low-probability, high-consequence positive events. Typical communications about state lotteries provide a virtual strategic textbook for opponents of risky technologies. The same techniques can be used to sell lottery tickets or sell opposition to risky technologies. Eight basic principles are enumerated.

  13. High-speed image transmission via the Advanced Communication Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Bazzill, Todd M.; Huang, H. K.; Thoma, George R.; Long, L. Rodney; Gill, Michael J.

    1996-05-01

    We are developing a wide area test bed network using the Advanced Communication Technology Satellite (ACTS) from NASA for high speed medical image transmission. The two test sites are the University of California, San Francisco, and the National Library of Medicine. The first phase of the test bed runs over a T1 link (1.544 Mbits/sec) using a Very Small Aperture Terminal. The second phase involves the High Data Rate Terminal via an ATM OC 3C (155 Mbits/sec) connection. This paper describes the experimental set up and some preliminary results from phase 1.

  14. Development of reprogrammable high frame-rate detector devices for laser communication pointing, acquisition and tracking

    NASA Astrophysics Data System (ADS)

    Norton, Terita; Conner, Kenneth; Covington, Richard; Ngo, Hung; Rink, Christine

    2008-02-01

    A Two Terminal Laser Communication Test Bed has been developed at The Aerospace Corporation. This paper presents the design and preliminary results of a reprogrammable detector within the Test Bed for use in pointing, acquisition, and tracking between a Satellite-to-Satellite Laser Communication link. The detector may be commanded by an emulated spacecraft Command & Data Handling subsystem to switch between full-array scanning and "small sized" N x M pixel Field of View (FOV) for high-rate laser tracking. The approach follows a parallel path to implement the signal processing algorithm on two different hardware resources: a Field Programmable Gate Array (FPGA) and a Digital Signal Processor (DSP). The focus of this effort is to present a methodology for testing and evaluating various techniques for advanced focal plane array (FPA) hardware, as well as sensor FPA control, image processing and laser beam X & Y position algorithms.

  15. High speed QPPM direct detection optical communication receivers for FSDD intersatellite links

    NASA Technical Reports Server (NTRS)

    Davidson, Frederic M.; Sun, Xiaoli

    1993-01-01

    This final report consists of four separate reports, one for each project involved in this contract. The first report is entitled '325 Mbps QPPM (quaternary pulse position modulation) Direct Detection Free Space Optical Communication Encoder and Receiver,' which was our primary work. The second report is entitled 'Test Results of the 325 Mbps QPPM High Speed Data Transmission GaAs ASICs,' which describes our work in connection with Galaxy Microsystems, Inc. who produced these ASICs for NASA. The third report, 'Receiver Performance Analysis of BPPM Optical Communication Systems Using 1.3 micron Wavelength Transmitter and InGaAs PIN Photodiodes,' was prepared at the request of the NASA/Photonics Branch for their efforts in upgrading the 1773 optical fiber data bus. The fourth report, 'Photomultiplier Tubes for Use at 1.064 micron Wavelength,' was also prepared at the request of the NASA/Photonics Branch as a research project.

  16. Novel optical cryptography using PANDA ring resonator for highly secured communication

    NASA Astrophysics Data System (ADS)

    Putthacharoen, Rattipong; Juleang, Pakorn; Mitatha, Somsak; Yupapin, Preecha P.

    2011-07-01

    We propose a novel method of an optical cryptography using the dark-bright soliton conversion control in a modified add/drop optical filter. By using the control arrangement, the obtained outputs of the dynamic states of dark-bright soliton can be used to form the key suppression for communication security application, in which the key recovery can be obtained by controlling the add/drop filter outputs. The optical cryptography consists of an add/drop filter which is used to generate the encryption and decryption keys from the optical keys (LIP signals). A Mach-Zehnder interferometer is used for multiplexing and de-multiplexing operations. Simulation results obtained shows, that the proposed system can be used to form a high security communication system.

  17. An Examination of the Structure of the Career Decision Self-Efficacy Scale (Short Form) among Italian High School Students

    ERIC Educational Resources Information Center

    Presti, Alessandro Lo; Pace, Francesco; Mondo, Marina; Nota, Laura; Casarubia, Provvidenza; Ferrari, Lea; Betz, Nancy E.

    2013-01-01

    This study aims to evaluate the factor structure of Career Decision Self-Efficacy scale-short form in a sample of Italian high school adolescents. confirmatory factor analysis (CFA) was used to test the degree to which a one-factor structure and a five-factor structure provided the best fit. In view of available research the five-factor structure…

  18. Large-amplitude plasma wave generation with a high-intensity short-pulse beat wave.

    PubMed

    Walton, B; Najmudin, Z; Wei, M S; Marle, C; Kingham, R J; Krushelnick, K; Dangor, A E; Clarke, R J; Poulter, M J; Hernandez-Gomez, C; Hawkes, S; Neely, D; Collier, J L; Danson, C N; Fritzler, S; Malka, V

    2002-12-15

    A short-pulse laser beat wave scheme for advanced particle accelerator applications is examined. A short, intense (3-ps, >10(18)-W cm(-2)) two-frequency laser pulse is produced by use of a modified chirped-pulse amplification scheme and is shown to produce relativistic plasma waves during interactions with low-density plasmas. The generation of plasma waves was observed by measurement of forward Raman scattering. Resonance was found to occur at an electron density many times that expected, owing to ponderomotive displacement of plasma within the focal region. PMID:18033483

  19. Method of high speed flow field influence and restrain on laser communication

    NASA Astrophysics Data System (ADS)

    Meng, Li-xin; Wang, Chun-hui; Qian, Cun-zhu; Wang, Shuo; Zhang, Li-zhong

    2013-08-01

    For laser communication performance which carried by airplane or airship, due to high-speed platform movement, the air has two influences in platform and laser communication terminal window. The first influence is that aerodynamic effect causes the deformation of the optical window; the second one is that a shock wave and boundary layer would be generated. For subsonic within the aircraft, the boundary layer is the main influence. The presence of a boundary layer could change the air density and the temperature of the optical window, which causes the light deflection and received beam spot flicker. Ultimately, the energy hunting of the beam spot which reaches receiving side increases, so that the error rate increases. In this paper, aerodynamic theory is used in analyzing the influence of the optical window deformation due to high speed air. Aero-optics theory is used to analyze the influence of the boundary layer in laser communication link. Based on this, we focused on working on exploring in aerodynamic and aero-optical effect suppression method in the perspective of the optical window design. Based on planning experimental aircraft types and equipment installation location, we optimized the design parameters of the shape and thickness of the optical window, the shape and size of air-management kit. Finally, deformation of the optical window and air flow distribution were simulated by fluid simulation software in the different mach and different altitude fly condition. The simulation results showed that the optical window can inhibit the aerodynamic influence after optimization. In addition, the boundary layer is smoothed; the turbulence influence is reduced, which meets the requirements of the airborne laser communication.

  20. Quality of Communication Life in Adolescents with High-Functioning Autism and Asperger Syndrome: A Feasibility Study

    ERIC Educational Resources Information Center

    Burgess, Sloane; Turkstra, Lyn S.

    2010-01-01

    Purpose: This study was designed to evaluate the feasibility of using the American Speech-Language-Hearing Association's Quality of Communication Life Scale (QCL; Paul et al., 2004) for a group of individuals with developmental communication disorders--adolescents with high-functioning autism/Asperger syndrome (HFA/AS). Perceptions of quality of…

  1. Visuospatial short-term memory explains deficits in tower task planning in high-functioning children with autism spectrum disorder.

    PubMed

    Zinke, Katharina; Fries, Eva; Altgassen, Mareike; Kirschbaum, Clemens; Dettenborn, Lucia; Kliegel, Matthias

    2010-01-01

    Previous findings on planning abilities in individuals with high-functioning autism spectrum disorder (HFA) are inconsistent. Exploring possible reasons for these mixed findings, the current study investigated the involvement of memory in planning performance in 15 children with HFA and 17 typically developing controls. In addition to planning abilities (measured with the Tower of London), short-term memory and delayed recall for verbal as well as visuospatial material were assessed. Findings suggest that particularly reduced efficiency in visuospatial short-term memory is associated with Tower task planning deficits in children with HFA. PMID:20221933

  2. Coaxial-type water load for measuring high voltage, high current and short pulse of a compact Marx system for a high power microwave source

    NASA Astrophysics Data System (ADS)

    Han, Jaeeun; Kim, Jung-ho; Park, Sang-duck; Yoon, Moohyun; Park, Soo Yong; Choi, Do Won; Shin, Jin Woo; So, Joon Ho

    2009-11-01

    A coaxial-type water load was used to measure the voltage output from a Marx generator for a high power microwave source. This output had a rise time of 20 ns, a pulse duration of a few hundred ns, and an amplitude up to 500 kV. The design of the coaxial water load showed that it is an ideal resistive divider and can also accurately measure a short pulse. Experiments were performed to test the performance of the Marx generator with the calibrated coaxial water load.

  3. Study of short haul high-density V/STOL transportation systems. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Solomon, H. L.

    1972-01-01

    Essential supporting data to the short haul transportation study are presented. The specific appendices are arena characteristics, aerospace transportation analysis computer program, economics, model calibration, STOLport siting and services path selection, STOL schedule definition, tabulated California corridor results, and tabulated Midwest arena results.

  4. Sustained Silent Reading and Young Adult Short Stories for High School Classes.

    ERIC Educational Resources Information Center

    Jensen, Terry L.; Jensen, Valarie S.

    2002-01-01

    Describes the implementation of a version of Sustained Silent Reading (SSR), called the DEAR (Drop Everything And Read) program, throughout their school. Presents their experience with the program in the KWL format (what we KNOW, what we WANTED to know, and what we LEARNED). Provides a bibliography of 12 young adult short stories used in the…

  5. Small-bandgap polymer solar cells with unprecedented short-circuit current density and high fill factor.

    PubMed

    Choi, Hyosung; Ko, Seo-Jin; Kim, Taehyo; Morin, Pierre-Olivier; Walker, Bright; Lee, Byoung Hoon; Leclerc, Mario; Kim, Jin Young; Heeger, Alan J

    2015-06-01

    Small-bandgap polymer solar cells (PSCs) with a thick bulk heterojunction film of 340 nm exhibit high power conversion efficiencies of 9.40% resulting from high short-circuit current density (JSC ) of 20.07 mA cm(-2) and fill factor of 0.70. This remarkable efficiency is attributed to maximized light absorption by the thick active layer and minimized recombination by the optimized lateral and vertical morphology through the processing additive. PMID:25899940

  6. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOEpatents

    Veligdan, James T.

    1994-01-01

    An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90.degree. angle of incidence.

  7. High Current Responsivity and Wide Modulation Bandwidth Terahertz Detector Using High-Electron-Mobility Transistor for Wireless Communication

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Nukariya, T.; Ueda, Y.; Otsuka, T.; Asada, M.

    2016-07-01

    A high-current-responsivity terahertz (THz) detector was fabricated using a broadband bow-tie antenna and an InAlAs/InGaAs high-electron-mobility transistor (HEMT) with a short gate length. High-current responsivity can be achieved by using a short gate length; the resulting high transconductance exhibited ballistic transport in the channel. We fabricated the HEMT detector with a 50-nm-long channel; the transconductance was 1.2 S/mm and the subthreshold slope was 120 mV/dec, yielding a high-current responsivity (˜5 A/W) and a cutoff frequency of 460 GHz. We also measured the modulation bandwidth of the THz detector using a heterodyne mixing technique with a uni-traveling carrier photodiode (UTC-PD) for providing the radio frequency (RF) and a frequency multiplier as a local oscillator. The intensity of the intermediate signal (IF) was measured by changing the frequency of the UTC-PD; very high bandwidths of up to 26 GHz were obtained. The experimental results agree well with electromagnetic simulations, which indicate that the bandwidth is determined by the external circuit. The conversion gain from RF to IF was -2 dB in the heterodyne mixing by using the HEMT detector.

  8. High Current Responsivity and Wide Modulation Bandwidth Terahertz Detector Using High-Electron-Mobility Transistor for Wireless Communication

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Nukariya, T.; Ueda, Y.; Otsuka, T.; Asada, M.

    2016-03-01

    A high-current-responsivity terahertz (THz) detector was fabricated using a broadband bow-tie antenna and an InAlAs/InGaAs high-electron-mobility transistor (HEMT) with a short gate length. High-current responsivity can be achieved by using a short gate length; the resulting high transconductance exhibited ballistic transport in the channel. We fabricated the HEMT detector with a 50-nm-long channel; the transconductance was 1.2 S/mm and the subthreshold slope was 120 mV/dec, yielding a high-current responsivity (˜5 A/W) and a cutoff frequency of 460 GHz. We also measured the modulation bandwidth of the THz detector using a heterodyne mixing technique with a uni-traveling carrier photodiode (UTC-PD) for providing the radio frequency (RF) and a frequency multiplier as a local oscillator. The intensity of the intermediate signal (IF) was measured by changing the frequency of the UTC-PD; very high bandwidths of up to 26 GHz were obtained. The experimental results agree well with electromagnetic simulations, which indicate that the bandwidth is determined by the external circuit. The conversion gain from RF to IF was -2 dB in the heterodyne mixing by using the HEMT detector.

  9. Calibration of the effective spring constant of ultra-short cantilevers for a high-speed atomic force microscope

    NASA Astrophysics Data System (ADS)

    Song, Yun-Peng; Wu, Sen; Xu, Lin-Yan; Zhang, Jun-Ming; Dorantes-Gonzalez, Dante J.; Fu, Xing; Hu, Xiao-Dong

    2015-06-01

    Ultra-short cantilevers are a new type of cantilever designed for the next generation of high-speed atomic force microscope (HS-AFM). Ultra-short cantilevers have smaller dimensions and higher resonant frequency than conventional AFM cantilevers. Moreover, their geometry may also be different from the conventional beam-shape or V-shape. These changes increase the difficulty of determining the spring constant for ultra-short cantilevers, and hence limit the accuracy and precision of force measurement based on a HS-AFM. This paper presents an experimental method to calibrate the effective spring constant of ultra-short cantilevers. By using a home-made AFM head, the cantilever is bent against an electromagnetic compensation balance under servo control. Meanwhile the bending force and the cantilever deflection are synchronously measured by the balance and the optical lever in the AFM head, respectively. Then the effective spring constant is simply determined as the ratio of the force to the corresponding deflection. Four ultra-short trapezoid shape cantilevers were calibrated using this method. A quantitative uncertainty analysis showed that the combined relative standard uncertainty of the calibration result is less than 2%, which is better than the uncertainty of any previously reported techniques.

  10. A highly reliable, autonomous data communication subsystem for an advanced information processing system

    NASA Technical Reports Server (NTRS)

    Nagle, Gail; Masotto, Thomas; Alger, Linda

    1990-01-01

    The need to meet the stringent performance and reliability requirements of advanced avionics systems has frequently led to implementations which are tailored to a specific application and are therefore difficult to modify or extend. Furthermore, many integrated flight critical systems are input/output intensive. By using a design methodology which customizes the input/output mechanism for each new application, the cost of implementing new systems becomes prohibitively expensive. One solution to this dilemma is to design computer systems and input/output subsystems which are general purpose, but which can be easily configured to support the needs of a specific application. The Advanced Information Processing System (AIPS), currently under development has these characteristics. The design and implementation of the prototype I/O communication system for AIPS is described. AIPS addresses reliability issues related to data communications by the use of reconfigurable I/O networks. When a fault or damage event occurs, communication is restored to functioning parts of the network and the failed or damage components are isolated. Performance issues are addressed by using a parallelized computer architecture which decouples Input/Output (I/O) redundancy management and I/O processing from the computational stream of an application. The autonomous nature of the system derives from the highly automated and independent manner in which I/O transactions are conducted for the application as well as from the fact that the hardware redundancy management is entirely transparent to the application.

  11. A high-average power tapered FEL amplifier at submillimeter frequencies using sheet electron beams and short-period wigglers

    SciTech Connect

    Bidwell, S.W.; Radack, D.J.; Antonsen, T.M. Jr.; Booske, J.H.; Carmel, Y.; Destler, W.W.; Granatstein, V.L.; Levush, B.; Latham, P.E.; Zhang, Z.X.

    1990-01-01

    A high-average-power FEL amplifier operating at submillimeter frequencies is under development at the University of Maryland. Program goals are to produce a CW, {approximately}1 MW, FEL amplifier source at frequencies between 280 GHz and 560 GHz. To this end, a high-gain, high-efficiency, tapered FEL amplifier using a sheet electron beam and a short-period (superconducting) wiggler has been chosen. Development of this amplifier is progressing in three stages: (1) beam propagation through a long length ({approximately}1 m) of short period ({lambda}{sub {omega}} = 1 cm) wiggler, (2) demonstration of a proof-of-principle amplifier experiment at 98 GHz, and (3) designs of a superconducting tapered FEL amplifier meeting the ultimate design goal specifications. 17 refs., 1 fig., 1 tab.

  12. Developments in Acoustic Navigation and Communication for High-Latitude Ocean Research

    NASA Astrophysics Data System (ADS)

    Gobat, J.; Lee, C.

    2006-12-01

    Developments in autonomous platforms (profiling floats, drifters, long-range gliders and propeller-driven vehicles) offer the possibility of unprecedented access to logistically difficult polar regions that challenge conventional techniques. Currently, however, navigation and telemetry for these platforms rely on satellite positioning and communications poorly suited for high-latitude applications where ice cover restricts access to the sea surface. A similar infrastructure offering basin-wide acoustic geolocation and telemetry would allow the community to employ autonomous platforms to address previously intractable problems in Arctic oceanography. Two recent efforts toward the development of such an infrastructure are reported here. As part of an observational array monitoring fluxes through Davis Strait, development of real-time RAFOS acoustic navigation for gliders has been ongoing since autumn 2004. To date, test deployments have been conducted in a 260 Hz field in the Pacific and 780 Hz fields off Norway and in Davis Strait. Real-time navigation accuracy of ~1~km is achievable. Autonomously navigating gliders will operate under ice cover beginning in autumn 2006. In addition to glider navigation development, the Davis Strait array moorings carry fixed RAFOS recorders to study propagation over a range of distances under seasonally varying ice cover. Results from the under-ice propagation and glider navigation experiments are presented. Motivated by the need to coordinate these types of development efforts, an international group of acousticians, autonomous platform developers, high-latitude oceanographers and marine mammal researchers gathered in Seattle, U.S.A. from 27 February -- 1 March 2006 for an NSF Office of Polar Programs sponsored Acoustic Navigation and Communication for High-latitude Ocean Research (ANCHOR) workshop. Workshop participants focused on summarizing the current state of knowledge concerning Arctic acoustics, navigation and communications

  13. Pairing in high-density neutron matter including short- and long-range correlations

    NASA Astrophysics Data System (ADS)

    Ding, Dong; Rios, Arnau; Dussan, Helber; Dickhoff, Willem; Witte, Sam; Polls, Artur

    2016-03-01

    To address open questions in neutron star phenomenology, pairing gaps of 1S0 and 3P2 -3F2 channels in a wide range of densities has been calculated using three different interactions (AV18 CDbonn N3LO). Traditionally, the Bardeen-Cooper-Schrieffer(BCS) approach has been used to compute gaps from bare nucleon-nucleon interactions. Here, we incorporate the influence of short- and long-range correlations in the pairing gaps. Short-range correlations (SRC) are treated including the appropriate fragmentation of single-particle states, and they suppress the gaps substantially. Long-range correlations(LRC) dress the pairing interaction via density and spin modes, and provide a relatively small correction. Results are relevant and parametrized in a user friendly way for neutron-star cooling scenarios, in particular in view of the recent observational data on Cassiopeia A.

  14. Pairing in high-density neutron matter including short- and long-range correlations

    NASA Astrophysics Data System (ADS)

    Ding, D.; Rios, A.; Dussan, H.; Dickhoff, W. H.; Witte, S. J.; Carbone, A.; Polls, A.

    2016-08-01

    Pairing gaps in neutron matter need to be computed in a wide range of densities to address open questions in neutron-star phenomenology. Traditionally, the Bardeen-Cooper-Schrieffer approach has been used to compute gaps from bare nucleon-nucleon interactions. Here we incorporate the influence of short- and long-range correlations in the pairing gaps. Short-range correlations are treated, including the appropriate fragmentation of single-particle states, and substantially suppress the gaps. Long-range correlations dress the pairing interaction via density and spin modes and provide a relatively small correction. We use different interactions, some with three-body forces, as a starting point to control for any systematic effects. Results are relevant for neutron-star cooling scenarios, in particular in view of the recent observational data on Cassiopeia A.

  15. Measurement of Short-Lived Fission-Product Yields of URANIUM-235 Using High-Resolution Gamma Spectra.

    NASA Astrophysics Data System (ADS)

    Tipnis, Sameer Vijay

    Independent yields of short-lived fission products produced by the thermal neutron induced fission of ^{235}U were determined from the measurements of high resolution gamma spectra. Comparisons were made to the recommended yield values tabulated in the ENDF/B-VI evaluated fission-product data base. Measurements of the gamma spectra were made with a high purity germanium detector (HPGe) using a NaI(Tl) annulus for Compton suppression. Use of beta-gamma coincidence reduced the random background and also allowed a precise definition of the delay time. The experiment was carried out at the 5.5 MV Van de Graaff facility at the University of Massachusetts Lowell. Rapid transfer of the fission fragments to a low background counting environment, a crucial factor in determining the yields of short-lived fission products, was enabled by a helium -jet tape transport system. The recommended yields in the evaluated data file are a combination of experimental and model-predicted values. The latter source is used since data from many short-lived fission products is still missing or poorly known. The results presented here, especially the ones for the very short-lived isotopes may be used to reduce the uncertainties associated with some of the existing values or to replace model-predicted yields. Gaussian distributions of elemental yields, based on the set of experimentally determined independent yields were examined. The feasibility of predicting unmeasured yields on the basis of charge and mass complementarity was also addressed.

  16. CTS United States experiments - A progress report. [Communications Technology Satellite for high power broadcasting

    NASA Technical Reports Server (NTRS)

    Robbins, W. H.; Donoughe, P. L.

    1976-01-01

    The Communications Technology Satellite (CTS) is a high-power broadcast satellite launched by NASA on January 17, 1976. CTS is the first satellite to operate at a frequency of 12 gigahertz and incorporates technology making possible new satellite telecommunications services. CTS is a cooperative program of the United States and Canada. This paper presents the results of the United States experimental activity to date. Wide segments of the population are involved in the Experiments Program, including the scientific community, other government agencies, industry, and the education and health entities. The experiments are associated with both technological objectives and the demonstration of new community and social services via satellite.

  17. Combinatorial FSK modulation for power-efficient high-rate communications

    NASA Technical Reports Server (NTRS)

    Wagner, Paul K.; Budinger, James M.; Vanderaar, Mark J.

    1991-01-01

    Deep-space and satellite communications systems must be capable of conveying high-rate data accurately with low transmitter power, often through dispersive channels. A class of noncoherent Combinatorial Frequency Shift Keying (CFSK) modulation schemes is investigated which address these needs. The bit error rate performance of this class of modulation formats is analyzed and compared to the more traditional modulation types. Candidate modulator, demodulator, and digital signal processing (DSP) hardware structures are examined in detail. System-level issues are also discussed.

  18. A high-efficiency 59- to 64-GHz TWT for intersatellite communications

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Ramins, Peter; Force, Dale A.; Limburg, Helen C.; Tammaru, Ivo

    1991-01-01

    The design of a 75-W, 59- to 64- GHz TWT with a predicted overall efficiency in excess of 40 percent is described. This intersatellite communications TWT, designated Model 961HA, employs a coupled-cavity slow-wave structure with a two-step velocity taper and an isotropic graphite multistage depressed collector (MDC). Because the RF efficiency of this TWT is less than 8 percent, an MDC design providing a very high collector efficiency was necessary to achieve the overall efficiency goal of 40 percent.

  19. High-speed communication detector characterization by bit error rate measurements

    NASA Technical Reports Server (NTRS)

    Green, S. I.

    1978-01-01

    Performance data taken on several candidate high data rate laser communications photodetectors is presented. Measurements of bit error rate versus signal level were made in both a 1064 nm system at 400 Mbps and a 532 nm system at 500 Mbps. RCA silicon avalanche photodiodes are superior at 1064 nm, but the Rockwell hybrid 3-5 avalanche photodiode preamplifiers offer potentially superior performance. Varian dynamic crossed field photomultipliers are superior at 532 nm, however, the RCA silicon avalanche photodiode is a close contender.

  20. Pulse Interval Modulation for Ultra-High Speed IR-UWB Communications Systems

    NASA Astrophysics Data System (ADS)

    Herceg, Marijan; Švedek, Tomislav; Matić, Tomislav

    2010-12-01

    This paper analyzes performances of the Pulse Interval Modulation (PIM) scheme for impulse radio ultra-wideband (IR-UWB) communication systems. Due to the PIM anisochronous nature, a tap delay line (TDL) coded division multiple access (CDMA) scheme based on strict optical orthogonal codes (SOOC) is proposed. This scheme is suitable for multiuser high-speed data asynchronous transmission applications because the average symbol length is shorter than in Pulse Position Modulation (PPM) schemes and it needs only chip synchronization. The error probability over the additive white Gaussian noise (AWGN) channel is derived in the single- and multi-user environment and compared with other modulation schemes.

  1. Circuit for Communication over DC Power Line Using High Temperature Electronics

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2014-01-01

    A high temperature communications circuit includes a power conductor for concurrently conducting electrical energy for powering circuit components and transmitting a modulated data signal, and a demodulator for demodulating the data signal and generating a serial bit stream based on the data signal. The demodulator includes an absolute value amplifier for conditionally inverting or conditionally passing a signal applied to the absolute value amplifier. The absolute value amplifier utilizes no diodes to control the conditional inversion or passing of the signal applied to the absolute value amplifier.

  2. Demonstration of high-speed multi-user multi-carrier CDMA visible light communication

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Wang, Yuanquan; Wang, Yiguang; Huang, Xingxing; Chi, Nan

    2015-02-01

    We experimentally demonstrated a high-speed multi-user multi-carrier code-division multiple access (MC-CDMA) visible light communication (VLC) system. By employing a commercially available red light emitting diode (LED) and an avalanche photo diode (APD), we achieved a 16-user VLC system enabled by MC-CDMA, pre- and post-equalization, with an overall bit rate of 750 Mb/s over 1.5 m free-space transmission. The measured bit error ratio (BER) of each user is below the 7% pre-forward-error-correction (pre-FEC) threshold of 3.8×10-3.

  3. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    ScienceCinema

    Jordan, Scott [Physik Instrumente

    2013-02-11

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  4. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    SciTech Connect

    Jordan, Scott

    2012-06-01

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  5. Wide-area technologies and services in the Trans-Pacific High Data Rate (HDR) satellite communications experiments

    NASA Technical Reports Server (NTRS)

    Hsu, E.; Hung, C.; Kadowaki, N.; Yoshimura, N.; Takahashi, T.; Shopbell, P.; Walker, G.; Wellnitz, D.; Gary, P.; Clark, G.; Yoshikawa, M.; desJardins, R.; Gill, M.; Tatsumi, H.

    2000-01-01

    This paper describes the technologies and services used in the experiments and demonstrations using the Trans-Pacific high data rate satellite communications infrastructure, and how the environment tasked protocol adaptability, scalability, efficiency, interoperability, and robustness.

  6. Integration and test of high-speed transmitter electronics for free-space laser communications

    NASA Technical Reports Server (NTRS)

    Soni, Nitin J.; Lizanich, Paul J.

    1994-01-01

    The NASA Lewis Research Center in Cleveland, Ohio, has developed the electronics for a free-space, direct-detection laser communications system demonstration. Under the High-Speed Laser Integrated Terminal Electronics (Hi-LITE) Project, NASA Lewis has built a prototype full-duplex, dual-channel electronics transmitter and receiver operating at 325 megabit S per second (Mbps) per channel and using quaternary pulse-position modulation (QPPM). This paper describes the integration and testing of the transmitter portion for future application in free-space, direct-detection laser communications. A companion paper reviews the receiver portion of the prototype electronics. Minor modifications to the transmitter were made since the initial report on the entire system, and this paper addresses them. The digital electronics are implemented in gallium arsenide integrated circuits mounted on prototype boards. The fabrication and implementation issues related to these high-speed devices are discussed. The transmitter's test results are documented, and its functionality is verified by exercising all modes of operation. Various testing issues pertaining to high-speed circuits are addressed. A description of the transmitter electronics packaging concludes the paper.

  7. High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

    NASA Astrophysics Data System (ADS)

    Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

    2016-06-01

    Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

  8. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

    PubMed

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M; Oh, Sang Ho; Margalith, Tal; Speck, James S; Nakamura, Shuji; Bowers, John E; DenBaars, Steven P

    2015-06-15

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature. PMID:26193595

  9. An integrated optical/acoustic communication system for seafloor observatories: A field test of high data rate communications at CORK 857D

    NASA Astrophysics Data System (ADS)

    Tivey, M.; Farr, N.; Ware, J.; Pontbriand, C.

    2010-12-01

    We report the successful deployment and testing of an underwater optical communication system that provides high data rate communications over a range of 100 meters from a deep sea borehole observatory located in the northeast Pacific. Optical underwater communications offers many advantages over acoustic or underwater wet mateable connections (UWMC). UMWCs requires periodic visits from a submersible or ROV to plug in and download data. Typically, these vehicles cannot perform any other tasks during these download periods - their time on station is limited, restricting the amount of data that can be downloaded. To eliminate the need for UWMCs requires the use of remote communication techniques such as acoustics or optical communications. Optical communications is capable of high data rates up to 10 mega bits per sec (Mbps) compared to acoustic data rates of 57 Kbps. We have developed an integrated optical/acoustic telemetry system (OTS) that uses an acoustic command system to control a high bandwidth, low latency optical communication system. In July 2010, we used the deep submersible ALVIN to install the Optical Telemetry System (OTS) at CORK 857D. The CORK is instrumented with a thermistor string and pressure sensors that record downhole formation pressures and temperatures within oceanic basement that is pressure sealed from the overlying water column. The seafloor OTS was plugged into the CORK’s existing UWMC to provide an optical and acoustic communication interface and additional data storage and battery power for the CORK to sample at 1 Hz data-rate, an increase over the normal 15 sec data sample rate. Using a CTD-mounted OTS lowered by wire from a surface ship, we established an optical communication link at 100 meters range at rates of 1, 5 and 10 Mbps with no bit errors. Tests were also done to establish the optical range of various data rates and the optical power of the system. After a week, we repeated the CTD-OTS experiment and downloaded 20 Mbytes

  10. Reconfigurable Antennas for High Data Rate Multi-beam Communication Systems

    NASA Technical Reports Server (NTRS)

    Bernhard, Jennifer T.; Michielssen, Eric

    2005-01-01

    High-speed (2-100 Mb/sec) wireless data communication - whether land- or satellite-based - faces a major challenge: high error rates caused by interference and unpredictable environments. A planar antenna system that can be reconfigured to respond to changing conditions has the potential to dramatically improve data throughput and system reliability. Moreover, new planar antenna designs that reduce array size, weight, and cost can have a significant impact on terrestrial and satellite communication system performance. This research developed new individually-reconfigurable planar antenna array elements that can be adjusted to provide multiple beams while providing increased scan angles and higher aperture efficiency than traditional diffraction-limited arrays. These new elements are microstrip spiral antennas with specialized tuning mechanisms that provide adjustable radiation patterns. We anticipate that these new elements can be used in both large and small arrays for inter-satellite communication as well as tracking of multiple mobile surface-based units. Our work has developed both theoretical descriptions as well as experimental prototypes of the antennas in both single element and array embodiments. The technical summary of the results of this work is divided into six sections: A. Cavity model for analysis and design of pattern reconfigurable antennas; B. Performance of antenna in array configurations for broadside and endfire operation; C. Performance of antenna in array configurations for beam scanning operation; D. Simulation of antennas in infinite phased arrays; E. Demonstration of antenna with commercially-available RF MEMS switches; F. Design of antenna MEMS switch combinations for direct simultaneous fabrication.

  11. First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap

    SciTech Connect

    Ettenauer, S.; Gallant, A. T.; Dilling, J.; Simon, M. C.; Chaudhuri, A.; Mane, E.; Delheij, P.; Pearson, M. R.; Brunner, T.; Chowdhury, U.; Simon, V. V.; Brodeur, M.; Andreoiu, C.; Audi, G.; Lopez-Urrutia, J. R. Crespo; Ullrich, J.; Gwinner, G.; Lapierre, A.; Lunney, D.; Ringle, R.

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed {beta} emitter {sup 74}Rb (T{sub 1/2}=65 ms). The determination of its atomic mass and an improved Q{sub EC} value are presented.

  12. First use of high charge states for mass measurements of short-lived nuclides in a Penning trap.

    PubMed

    Ettenauer, S; Simon, M C; Gallant, A T; Brunner, T; Chowdhury, U; Simon, V V; Brodeur, M; Chaudhuri, A; Mané, E; Andreoiu, C; Audi, G; López-Urrutia, J R Crespo; Delheij, P; Gwinner, G; Lapierre, A; Lunney, D; Pearson, M R; Ringle, R; Ullrich, J; Dilling, J

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed β emitter 74Rb (T(1/2)=65  ms). The determination of its atomic mass and an improved Q(EC) value are presented. PMID:22243307

  13. A longitudinal bunch rotation and acceleration scheme for a short bunch and high energy spread muon beam

    NASA Astrophysics Data System (ADS)

    Scrivens, R.

    2000-08-01

    A neutrino factory for νμ would require a high-power proton beam bombarding a target to produce pions that decay to muons which can be accelerated. Such a proton driver could be realized with a high-power linac, which could produce short bunches in the interaction point. If the bunch structure could be maintained to the input of a linear accelerator, the re-bunching of muons would be avoided. A preliminary design of the longitidinal beam dynamics for the acceleration of short muon bunches with a large-energy spread will be presented. Muons bunches are assumed at the linac input to consist of a phase space occupying a region from 200-400 MeV with a bunch length of 24 ps. They are captured and accelerated to 1 GeV with a resulting bunch length of 100 ps. Seventy five percent of the muons are transported within these limits.

  14. Spectral mirror for ultra-short, high peak power, multi-PW Ti:sapphire lasers

    NASA Astrophysics Data System (ADS)

    Giambruno, F.; Freneaux, A.; Chériaux, G.

    2013-05-01

    A multilayer mirror for spectral filtering adapted to ultra-short and multi-PW Ti:Sa laser has been designed, manufactured and characterized. The method used to determine both the reflectivity shape and the coating design leads to global compensation of gain narrowing, saturation and spectral phase. The result is a spectral control on 200 nm range while keeping a flat spectral phase. This kind of filter will enable obtaining 15 fs pulse duration for multi-PW laser systems based on Ti:Sa.

  15. Diagnostics of high-brightness short-pulse lasers and the plasmas they generate

    SciTech Connect

    Kyrala, G.A.; Fulton, R.D.; Cobble, J.A.; Schappert, G.T.; Taylor, A.J.

    1994-02-01

    The properties of a laser influence the interaction of the intense laser light with materials. The authors will describe some of the diagnostics that they have implemented at the Los Alamos Bright Source to correlate the changes in the x-ray spectrum and temporal history of a laser generated silicon plasmas with the changes of the incident XeCl laser light. One property is of special interest, the existence of a short prepulse. They find that the prepulse enhances the generation of the x-rays from a later pulse.

  16. High-performance diamond-based single-photon sources for quantum communication

    NASA Astrophysics Data System (ADS)

    Su, Chun-Hsu; Greentree, Andrew D.; Hollenberg, Lloyd C. L.

    2009-11-01

    Quantum communication places stringent requirements on single-photon sources. Here we report a theoretical study of the cavity Purcell enhancement of two diamond point defects, the nickel-nitrogen (NE8) and silicon-vacancy (SiV) centers, for high-performance, near on-demand single-photon generation. By coupling the centers strongly to high-finesse optical photonic-band-gap cavities with modest quality factor Q=O(104) and small mode volume V=O(λ3) , these system can deliver picosecond single-photon pulses at their zero-phonon lines with probabilities of 0.954 (NE8) and 0.812 (SiV) under a realistic optical excitation scheme. The undesirable blinking effect due to transitions via metastable states can also be suppressed with O(10-4) blinking probability. We analyze the application of these enhanced centers, including the previously studied cavity-enhanced nitrogen-vacancy (NV) center, to long-distance Bennett-Brassard 1984 protocol quantum key distribution (QKD) in fiber-based, open-air terrestrial and satellite-ground setups. In this comparative study, we show that they can deliver performance comparable with decoy state implementation with weak coherent sources, and are most suitable for open-air communication.

  17. GaAs Photonic Integrated Circuit (PIC) development for high performance communications

    SciTech Connect

    Sullivan, C.T.

    1998-03-01

    Sandia has established a foundational technology in photonic integrated circuits (PICs) based on the (Al,Ga,In)As material system for optical communication, radar control and testing, and network switching applications at the important 1.3{mu}m/1.55{mu}m wavelengths. We investigated the optical, electrooptical, and microwave performance characteristics of the fundamental building-block PIC elements designed to be as simple and process-tolerant as possible, with particular emphasis placed on reducing optical insertion loss. Relatively conventional device array and circuit designs were built using these PIC elements: (1) to establish a baseline performance standard; (2) to assess the impact of epitaxial growth accuracy and uniformity, and of fabrication uniformity and yield; (3) to validate our theoretical and numerical models; and (4) to resolve the optical and microwave packaging issues associated with building fully packaged prototypes. Novel and more complex PIC designs and fabrication processes, viewed as higher payoff but higher risk, were explored in a parallel effort with the intention of meshing those advances into our baseline higher-yield capability as they mature. The application focus targeted the design and fabrication of packaged solitary modulators meeting the requirements of future wideband and high-speed analog and digital data links. Successfully prototyped devices are expected to feed into more complex PICs solving specific problems in high-performance communications, such as optical beamforming networks for phased array antennas.

  18. Core Communications

    ERIC Educational Resources Information Center

    Block, Greg; Ross, J. D.; Mulder, David

    2011-01-01

    The website--it is where people go to find out anything and everything about a school, college, or university. In the relatively short life of the Internet, institutional websites have moved from the periphery to center stage and become strategically integral communications and marketing tools. As the flow of information accelerates and new…

  19. Spectral signature of atmospheric reflection in Hercules X-1/HZ Hercules during low and short high states

    NASA Astrophysics Data System (ADS)

    Abdallah, M. H.; Leahy, D. A.

    2015-11-01

    We analyse RXTE/PCA X-ray spectra of the binary X-ray pulsar Her X-1/HZ Her during short high state and one binary orbit in the preceding low state, just before short high turn-on. The spectrum is well described by two continuum components (absorbed and unabsorbed). The resulting spectral parameters are modulated with orbital phase. During low state, a significant component of the flux, and its spectrum, is consistent with X-ray reflection off the face of the companion star HZ Her. This component has a significantly harder X-ray spectrum than the rest of the flux from the Her X-1 system. A second component in low state is consistent with emission from the accretion disc corona. During short high, a third strong component is present with a softer spectrum, which is associated with the neutron star and accretion disc. Due to this direct emission from the neutron star and accretion disc, the reflected emission is less clear; however, parameters and fluxes modulations during short high state indicate its presence. In low state, the hard X-ray flux (hν > 10 keV) peaks at orbital phase φorb ≃ 0.55, which is expected from a simple model of atmospheric reflection from the companion star. The offset indicates an asymmetry in the X-ray illumination of the companion, which could be due to shadowing of the the inner face of HZ Her by the accretion disc and/or stream.

  20. Survival of human epidermal keratinocytes after short-duration high temperature: synthesis of HSP70 and IL-8.

    PubMed

    Bowman, P D; Schuschereba, S T; Lawlor, D F; Gilligan, G R; Mata, J R; DeBaere, D R

    1997-06-01

    Thermal injury by short pulses (1-30 s) of relatively high temperature (50-68 degrees C) was investigated in normal human epidermal keratinocytes (NHEK). NHEK were cultured on plastic cover-slips and dipped in medium held at various temperatures. Survival assessed by methylthiazol tetrazolium reduction assay at 6 days postheating demonstrated an inverse time-temperature relationship that indicated that most cells could survive after a 1-s, 60 degrees C exposure or a 30-s, 55 degrees C exposure. Arrhenius plots of the data indicated major transition points for cell injury at 50 and 60 degrees C. Heat shock protein 70 (HSP70) and interleukin-8 (IL-8) were both induced by elevation of temperature between 50 and 60 degrees C for as short a time as 1 s. HSP70 synthesis stimulated by short, high pulses of heat appeared to induce thermotolerance. These results demonstrate that brief exposure to relatively high temperature can induce HSP70 and IL-8 synthesis in keratinocytes. PMID:9227428

  1. Short rotation willow coppice in Wales: High production under adverse environmental conditions?

    SciTech Connect

    Slater, F.M.; Hodson, R.W.; Randerson, P.F.

    1995-11-01

    The production of short rotation willow coppice in central Wales was once regarded as a vain hope rather than a distinct possibility. Research at the University of Wales, Cardiff, Field Station at Llysdinam in mid-Wales over the last four years has proven that it is possible to produce a commercially viable crop on very poor upland soils and at an altitude of almost 300m provided that lime and inorganic fertilizers are added. Because of the national need to find new routes for the disposal of sewage sludge, its addition to short rotation coppice serves the dual purpose of disposal and nutrient addition. Over the first two years of the sludging experiment, it was found that the addition of 300 m{sup 3}ha{sup -1} of digested sewage sludge significantly increased crop weight, at least in the first year. Unfortunately, the crop yields did not reach those obtained using inorganic fertilizers at the same site but it is suggested that a repeated application regime might improve overall crop yield.

  2. High-Fidelity Down-Conversion Source for Secure Communications Using On-Demand Single Photons

    NASA Technical Reports Server (NTRS)

    Roberts, Tony

    2015-01-01

    AdvR, Inc., has built an efficient, fully integrated, waveguide-based source of spectrally uncorrelated photon pairs that will accelerate research and development (R&D) in the emerging field of quantum information science. Key to the innovation is the use of submicron periodically poled waveguides to produce counter propagating photon pairs, which is enabled by AdvR's patented segmented microelectrode poling technique. This novel device will provide a high brightness source of down-conversion pairs with enhanced spectral properties and low attenuation, and it will operate in the visible to the mid-infrared spectral region. A waveguide-based source of spectrally and spatially pure heralded photons will contribute to a wide range of NASA's advanced technology development efforts, including on-demand single photon sources for high-rate spaced-based secure communications.

  3. High-sensitivity DPSK receiver for high-bandwidth free-space optical communication links.

    PubMed

    Juarez, Juan C; Young, David W; Sluz, Joseph E; Stotts, Larry B

    2011-05-23

    A high-sensitivity modem and high-dynamic range optical automatic gain controller (OAGC) have been developed to provide maximum link margin and to overcome the dynamic nature of free-space optical links. A sensitivity of -48.9 dBm (10 photons per bit) at 10 Gbps was achieved employing a return-to-zero differential phase shift keying based modem and a commercial Reed-Solomon forward error correction system. Low-noise optical gain was provided by an OAGC with a noise figure of 4.1 dB (including system required input loses) and a dynamic range of greater than 60 dB. PMID:21643335

  4. Mission Control Operations: Employing a New High Performance Design for Communications Links Supporting Exploration Programs

    NASA Technical Reports Server (NTRS)

    Jackson, Dan E., Jr.

    2015-01-01

    The planetary exploration programs demand a totally new examination of data multiplexing, digital communications protocols and data transmission principles for both ground and spacecraft operations. Highly adaptive communications devices on-board and on the ground must provide the greatest possible transmitted data density between deployed crew personnel, spacecraft and ground control teams. Regarding these requirements, this proposal borrows from research into quantum mechanical computing by applying the concept of a qubit, a single bit that represents 16 states, to radio frequency (RF) communications link design for exploration programs. This concept of placing multiple character values into a single data bit can easily make the evolutionary steps needed to meet exploration mission demands. To move the qubit from the quantum mechanical research laboratory into long distance RF data transmission, this proposal utilizes polarization modulation of the RF carrier signal to represent numbers from zero to fifteen. It introduces the concept of a binary-to-hexadecimal converter that quickly chops any data stream into 16-bit words and connects variously polarized feedhorns to a single-frequency radio transmitter. Further, the concept relies on development of a receiver that uses low-noise amplifiers and an antenna array to quickly assess carrier polarity and perform hexadecimal to binary conversion. Early testbed experiments using the International Space Station (ISS) as an operations laboratory can be implemented to provide the most cost-effective return for research investment. The improvement in signal-to-noise ratio while supporting greater baseband data rates that could be achieved through this concept justifies its consideration for long-distance exploration programs.

  5. High performance computing and communications: Advancing the frontiers of information technology

    SciTech Connect

    1997-12-31

    This report, which supplements the President`s Fiscal Year 1997 Budget, describes the interagency High Performance Computing and Communications (HPCC) Program. The HPCC Program will celebrate its fifth anniversary in October 1996 with an impressive array of accomplishments to its credit. Over its five-year history, the HPCC Program has focused on developing high performance computing and communications technologies that can be applied to computation-intensive applications. Major highlights for FY 1996: (1) High performance computing systems enable practical solutions to complex problems with accuracies not possible five years ago; (2) HPCC-funded research in very large scale networking techniques has been instrumental in the evolution of the Internet, which continues exponential growth in size, speed, and availability of information; (3) The combination of hardware capability measured in gigaflop/s, networking technology measured in gigabit/s, and new computational science techniques for modeling phenomena has demonstrated that very large scale accurate scientific calculations can be executed across heterogeneous parallel processing systems located thousands of miles apart; (4) Federal investments in HPCC software R and D support researchers who pioneered the development of parallel languages and compilers, high performance mathematical, engineering, and scientific libraries, and software tools--technologies that allow scientists to use powerful parallel systems to focus on Federal agency mission applications; and (5) HPCC support for virtual environments has enabled the development of immersive technologies, where researchers can explore and manipulate multi-dimensional scientific and engineering problems. Educational programs fostered by the HPCC Program have brought into classrooms new science and engineering curricula designed to teach computational science. This document contains a small sample of the significant HPCC Program accomplishments in FY 1996.

  6. Grand Challenges: High Performance Computing and Communications. The FY 1992 U.S. Research and Development Program.

    ERIC Educational Resources Information Center

    Federal Coordinating Council for Science, Engineering and Technology, Washington, DC.

    This report presents a review of the High Performance Computing and Communications (HPCC) Program, which has as its goal the acceleration of the commercial availability and utilization of the next generation of high performance computers and networks in order to: (1) extend U.S. technological leadership in high performance computing and computer…

  7. Novel High-Voltage, High-Power Piezoelectric Transformer Developed and Demonstrated for Space Communications Applications

    NASA Technical Reports Server (NTRS)

    Carazo, Alfredo V.; Wintucky, Edwin G.

    2004-01-01

    Improvements in individual piezoelectric transformer (PT) performance and the combination of these PTs in a unique modular topology under a Phase I contract with the NASA Glenn Research Center have enabled for the first time the simultaneous achievement of both high voltage and high power at much higher levels than previously obtained with any PT. Feasibility was demonstrated by a prototype transformer (called a Tap-Soner), which is shown in the preceding photograph as part of a direct-current to direct-current (dc-dc) converter having two outputs rated at 1.5 kV/5 W and 4.5 kV/20 W. The power density of 3.5 W/cm3 is significantly lower than for magnetic transformers with the same voltage and power output. This development, which is being done under a Small Business Innovation Research (SBIR) contract by Face Electronics, LC (Norfolk, VA), is based on improvements in the materials and design of Face's basic patented Transoner-T3 PT, shown in the left in the following figure. The T3 PT is most simply described as a resonant multilayer transducer where electrical energy at the input section is efficiently mechanically coupled to the output section, which then vibrates in a fundamental longitudinal mode to generate a high gain in voltage. The piezoelectric material used is a modified lead-zirconium-titanate-based ceramic. One of the significant improvements in PT design was the incorporation of a symmetrical double input layer, shown on the right in the following figure, which eliminated the lossy bending vibration modes characteristic of a single input layer. The performance of the improved PT was optimized to 1.5 kV/5 W. The next step was devising a way to combine the individual PTs in a modular circuit topology needed to achieve the desired high voltage and power output. Since the optimum performance of the individual PT occurs at resonance, the most efficient operation of the modular transformer was achieved by using a separate drive circuit for each PT. The

  8. Acute Physiological Responses to Short- and Long-Stage High-Intensity Interval Exercise in Cardiac Rehabilitation: A Pilot Study

    PubMed Central

    Tschakert, Gerhard; Kroepfl, Julia M.; Mueller, Alexander; Harpf, Hanns; Harpf, Leonhard; Traninger, Heimo; Wallner-Liebmann, Sandra; Stojakovic, Tatjana; Scharnagl, Hubert; Meinitzer, Andreas; Pichlhoefer, Patriz; Hofmann, Peter

    2016-01-01

    Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) from IET; 2) long HIIE with a tpeak of 4 min, Ppeak was corresponding to the power output at 85 % of maximal heart rate (HRmax) from IET; 3) CE with a target workload equal to Pmean of both HIIE modes. Acute metabolic and peak cardiorespiratory responses were significantly higher during long HIIE compared to short HIIE and CE (p < 0.05) except HRpeak which tended to be higher in long HIIE than in short HIIE (p = 0.08). Between short HIIE and CE, no significant difference was found for any parameter. Acute responses of cardiovascular and inflammatory biomarkers and catecholamines didn’t show any significant difference between tests (p > 0.05). All health-related variables remained in a normal range in any test except NT-proBNP, which was already elevated at baseline. Despite a high Ppeak particularly in short HIIE, both HIIE modes were as safe and as well tolerated as moderate CE in cardiac patients by using our methodological approach. Key points High-intensity interval exercise (HIIE

  9. High temperature, short term tensile strength of C6000/PMR-15 composites

    NASA Technical Reports Server (NTRS)

    Digiovanni, P. R.; Paterson, D.

    1985-01-01

    Tensile tests were conducted on 0 unidirectionally reinforced Celion 6000 graphite fibers in PMR-15 polyimide matrix. Tensile strengths for coupons subjected to short and long term uniform temperatures were obtained. Thick coupons, heated on one side to produce significant transient through thickness temperature gradients, were tested and compared to the strength of specimens with uniform temperature distributions. All coupons were radiantly heated and reached maximum test temperatures within 15 sec. Tensile loads were applied to the coupons after 15 sec of elevated temperature exposure. Loading rates were selected so that specimen failures occurred within a maximum of 45 sec after reaching the test temperature. Results indicate that significant tensile strength remains beyond the material post cure temperature.

  10. High Energy, Short Pulse Fiber Injection Lasers at Lawrence Livermore National Laboratory

    SciTech Connect

    Dawson, J W; Messerly, M J; Phan, H H; Crane, J K; Beach, R J; Siders, C W; Barty, C J

    2008-09-10

    A short pulse fiber injection laser for the Advanced Radiographic Capability (ARC) on the National Ignition Facility (NIF) has been developed at Lawrence Livermore National Laboratory (LLNL). This system produces 100 {micro}J pulses with 5 nm of bandwidth centered at 1053 nm. The pulses are stretched to 2.5 ns and have been recompressed to sub-ps pulse widths. A key feature of the system is that the pre-pulse power contrast ratio exceeds 80 dB. The system can also precisely adjust the final recompressed pulse width and timing and has been designed for reliable, hands free operation. The key challenges in constructing this system were control of the signal to noise ratio, dispersion management and managing the impact of self phase modulation on the chirped pulse.

  11. High power test of a wideband diplexer with short-slotted metal half mirrors for electron cyclotron current drive system

    SciTech Connect

    Saigusa, M.; Atsumi, K.; Yamaguchi, T.; Nagashima, K.; Oda, Y.; Fukunari, M.; Sakamoto, K.

    2014-02-12

    The wideband high power diplexer has been developed for combining and fast switching of high power millimeter waves generated by a dual frequency gyrotron. The actual diplexer was tested at the frequency band of 170 GHz in low power. After adjusting a resonant frequency of diplexer for the gyrotron frequency, the evacuated wideband diplexer with short-slotted metal half mirrors was tested at an incident power of about 150 kW, a pulse duration of 30 ms and a frequency band of 170.2–170.3 GHz. Any discharge damage was not observed in the diplexer.

  12. The simulation of hard X-ray generation at ultra-short laser pulse interaction with high-Z targets

    SciTech Connect

    Lykov, V. A.; Chernyakov, V. E.; Chikulaev, A. A.; Kandiev, Ya. Z.; Nikolaev, V. G.

    1997-04-15

    The simulations of fast electrons interaction with matter were performed by using of ERA code. The yield and angular distribution of bremsstrahlung and fluorescence K-{alpha} X-ray radiation calculated by PRIZMA code for experiments on interaction of ultra-short laser pulses with high-Z targets at intensities of 10{sup 15}-10{sup 18} W/cm{sup 2} are presented. Spherical targets with conical hollows and conical targets of high-Z matter are proposed for experiments with picosecond lasers to increase the brightness of hard X-ray source.

  13. High power test of a wideband diplexer with short-slotted metal half mirrors for electron cyclotron current drive system

    NASA Astrophysics Data System (ADS)

    Saigusa, M.; Atsumi, K.; Yamaguchi, T.; Nagashima, K.; Oda, Y.; Fukunari, M.; Sakamoto, K.

    2014-02-01

    The wideband high power diplexer has been developed for combining and fast switching of high power millimeter waves generated by a dual frequency gyrotron. The actual diplexer was tested at the frequency band of 170 GHz in low power. After adjusting a resonant frequency of diplexer for the gyrotron frequency, the evacuated wideband diplexer with short-slotted metal half mirrors was tested at an incident power of about 150 kW, a pulse duration of 30 ms and a frequency band of 170.2-170.3 GHz. Any discharge damage was not observed in the diplexer.

  14. Language Arts Practices in the Instruction of Oral Communication in California High Schools.

    ERIC Educational Resources Information Center

    Barnes, Judith A.; Hayes, Andrew F.

    1995-01-01

    Expresses concern with the trend in K-12 education to subsume oral communication programs under the rubric of language arts in English departments. Uses California as a case study to examine whether English teachers are integrating speech communication into the English classroom. Finds that little direct instruction in communication principles and…

  15. Laser Communications and Fiber Optics Lab Manual. High-Technology Training Module.

    ERIC Educational Resources Information Center

    Biddick, Robert

    This laboratory training manual on laser communications and fiber optics may be used in a general technology-communications course for ninth graders. Upon completion of this exercise, students achieve the following goals: match concepts with laser communication system parts; explain advantages of fiber optic cable over conventional copper wire;…

  16. High-dose short-term chlorambucil for intractable sympathetic ophthalmia and Behçet's disease.

    PubMed Central

    Tessler, H H; Jennings, T

    1990-01-01

    We treated five patients with intractable sympathetic ophthalmia and six patients with severe Behçet's disease by high-dose, short-term chlorambucil therapy. We used a total dose ranging from 306 mg to 4.2 g and a duration of therapy no longer than 36 weeks and in most cases less than 24 weeks. After termination of therapy all 11 patients had a sustained remission of their eye disease. Unless subretinal neovascularisation was present, all had a final visual acuity of 20/50 or better. Malignancy has not developed in any of our cases, with a follow-up ranging from 6 months to 12 years (mean, 4.5 years). Although 30- and 40-year follow-ups and larger numbers of patients may be necessary fully to realise the risks of chlorambucil, we believe that our high-dose, short-term regimen (Behçet's disease: average duration, 23 weeks; average total dose 2.2 g; sympathetic ophthalmia: average duration, 11 weeks; total average dose, 0.9 g) may be safer than previously reported chlorambucil regimens of one to two years or longer. In addition we fulfilled our aim of discontinuing all concomitant systemic corticosteroids within a relatively short time (usually six to eight weeks). PMID:2378842

  17. High-speed communications enabling real-time video for battlefield commanders using tracked FSO

    NASA Astrophysics Data System (ADS)

    Al-Akkoumi, Mouhammad K.; Huck, Robert C.; Sluss, James J., Jr.

    2007-04-01

    Free Space Optics (FSO) technology is currently in use to solve the last-mile problem in telecommunication systems by offering higher bandwidth than wired or wireless connections when optical fiber is not available. Incorporating mobility into FSO technology can contribute to growth in its utility. Tracking and alignment are two big challenges for mobile FSO communications. In this paper, we present a theoretical approach for mobile FSO networks between Unmanned Aerial Vehicles (UAVs), manned aerial vehicles, and ground vehicles. We introduce tracking algorithms for achieving Line of Sight (LOS) connectivity and present analytical results. Two scenarios are studied in this paper: 1 - An unmanned aerial surveillance vehicle, the Global Hawk, with a stationary ground vehicle, an M1 Abrams Main Battle Tank, and 2 - a manned aerial surveillance vehicle, the E-3A Airborne Warning and Control System (AWACS), with an unmanned combat aerial vehicle, the Joint Unmanned Combat Air System (J-UCAS). After initial vehicle locations have been coordinated, the tracking algorithm will steer the gimbals to maintain connectivity between the two vehicles and allow high-speed communications to occur. Using this algorithm, data, voice, and video can be sent via the FSO connection from one vehicle to the other vehicle.

  18. A Simple Semaphore Signaling Technique for Ultra-High Frequency Spacecraft Communications

    NASA Technical Reports Server (NTRS)

    Butman, S.; Satorius, E.; Ilott, P.

    2005-01-01

    For planetary lander missions such as the upcoming Phoenix mission to Mars, the most challenging phase of the spacecraft-to-ground communications is during the critical phase termed entry, descent, and landing (EDL). At 8.4 GHz (X-band), the signals received by the largest Deep Space Network (DSN) antennas can be too weak for even 1 bit per second (bps) and therefore not able to communicate critical information to Earth. Fortunately, the lander s ultra-high frequency (UHF) link to an orbiting relay can meet the EDL requirements, but the data rate needs to be low enough to fit the capability of the UHF link during some or all of EDL. On Phoenix, the minimum data rate of the as-built UHF radio is 8 kbps and requires a signal level at the Odyssey orbiter of at least -120 dBm. For lower signaling levels, the effective data rate needs to be reduced, but without incurring the cost of rebuilding and requalifying the equipment. To address this scenario, a simple form of frequency-shift keying (FSK) has been devised by appropriately programming the data stream that is input to the UHF transceiver. This article describes this technique and provides performance estimates. Laboratory testing reveals that input signal levels at -140 dBm and lower can routinely be demodulated with the proposed signaling scheme, thereby providing a 20-dB and greater margin over the 8-kbps threshold.

  19. Short Circuits or Superconductors? Effects of Group Composition on High-Achieving Students' Science Assessment Performance.

    ERIC Educational Resources Information Center

    Webb, Noreen M.; Nemer, Kariane Mari; Zuniga, Stephen

    2002-01-01

    Studied the effects of group ability composition (homogeneous versus heterogeneous) on group processes and outcomes for high-ability students completing science assessments. Results for 83 high ability students show the quality of group functioning serves as the strongest predictor of high-ability students' performance and explained much of the…

  20. Communicating the Benefits of a Full Sequence of High School Science Courses

    NASA Astrophysics Data System (ADS)

    Nicholas, Catherine Marie

    High school students are generally uninformed about the benefits of enrolling in a full sequence of science courses, therefore only about a third of our nation's high school graduates have completed the science sequence of Biology, Chemistry and Physics. The lack of students completing a full sequence of science courses contributes to the deficit in the STEM degree production rate needed to fill the demand of the current job market and remain competitive as a nation. The purpose of the study was to make a difference in the number of students who have access to information about the benefits of completing a full sequence of science courses. This dissertation study employed qualitative research methodology to gain a broad perspective of staff through a questionnaire and document review and then a deeper understanding through semi-structured interview protocol. The data revealed that a universal sequence of science courses in the high school district did not exist. It also showed that not all students had access to all science courses; students were sorted and tracked according to prerequisites that did not necessarily match the skill set needed for the courses. In addition, the study showed a desire for more support and direction from the district office. It was also apparent that there was a disconnect that existed between who staff members believed should enroll in a full sequence of science courses and who actually enrolled. Finally, communication about science was shown to occur mainly through counseling and peers. A common science sequence, detracking of science courses, increased communication about the postsecondary and academic benefits of a science education, increased district direction and realistic mathematics alignment were all discussed as solutions to the problem.