WorldWideScience

Sample records for satellites transmitted reconnaisance

  1. Phased Array Transmit Antenna for a Satellite

    Science.gov (United States)

    Huggins, R. W.; Heisen, P. T.; Miller, G. E.; McMeen, D. J.; Perko, K. L.

    1999-01-01

    Active phased array antennas with electronically scanned beams offer advantages over high gain parabolic dish antennas currently used on spacecraft. Benefits include the elimination of deployable structures, no moving parts, and no torque disturbances that moving antennas impart to the spacecraft. The latter results in the conservation of spacecraft power, and the ability to take precision optical data while transmitting data. Such an antenna has been built under a contract from NASA Goddard Space Flight Center for the New Millennium Program EO- 1 satellite where it will act as the primary highspeed scientific data communication link. The antenna operates at X-band, has an integral controller and power conditioner, communicates with the spacecraft over a 1773 optical data bus, and is space qualified for low earth orbit (705 Km altitude). The nominal mission length is one year, and the operational requirement is for one 10 minute transmission a day over Spitsbergen, Norway. Details of the antenna and its performance will be described in the following paper.

  2. On intermodulation beams of satellite DBF transmitting multibeam array antenna

    Science.gov (United States)

    Zhao, Hongmei; Wang, Huali; Mu, Shanxiang

    2007-11-01

    Digital beamforming (DBF) transmitting multibeam planar array antenna with nonlinear behaviors of solid-state power amplifiers (SSPA) is discussed. This paper investigates the intermodulation beams produced by the nonlinearity characteristics of the SSPA with multiple carrier components. The Shimbo model is simplified to describe the nonlinear behaviors of SSPA. The optimal SSPA input back-off (IBO) point which is given the desired the carrier and the intermodulatin ratio (C/IM) is simulated. And the tradeoffs between linearity and efficiency of the power amplifier which influence this IBO is also discussed, helping to selecting suitable SSPA device and reducing the dc power consumption in satellite array antenna system.

  3. 6 × 20 Gbps Hybrid WDM-PI Inter-satellite System under the Influence of Transmitting Pointing Errors

    Science.gov (United States)

    Chaudhary, Sushank; Sharma, Abhishek; Chaudhary, Neha

    2016-12-01

    Inter-satellite communication is a revolutionary technique used to establish communication between satellites in space. One of the major challenges in inter-satellite link is transmitting pointing errors, which causes turbulences in the link. This work is focussed on successful transmission of 120 Gbps high-speed data over 1,000 km by adopting hybrid wavelength division multiplexing scheme and polarization interleaving scheme under the influence of transmitting pointing error.

  4. Backup Communication Routing Through Internet Satellite, WINDS for Transmitting of Disaster Relief Data

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2011-09-01

    Full Text Available A countermeasure for round trip delay which occurs in between satellite and ground with network accelerator is investigated together with operating system dependency on effectiveness of accelerator. Also disaster relief data transmission experiments are conducted for mitigation of disaster together with acceleration of disaster related data transmission between local government and disaster prevention center. Disaster relief information including remote sensing satellite images and information from the disaster occurred areas to local government for creation of evacuation information is accelerated so that it becomes possible to send them to the residents in the suffered areas due to disaster through data broadcasting in the digital TV channel.

  5. Experimental Results for the Multipath Performance of Galileo Signals Transmitted by GIOVE-A Satellite

    Directory of Open Access Journals (Sweden)

    Andrew Simsky

    2008-01-01

    Full Text Available Analysis of GIOVE-A signals is an important part of the in-orbit validation phase of the Galileo program. GIOVE-A transmits the ranging signals using all the code modulations currently foreseen for the future Galileo and provides a foretaste of their performance in real-life applications. Due to the use of advanced code modulations, the ranging signals of Galileo provide significant improvement of the multipath performance as compared to current GPS. In this paper, we summarize the results of about 1.5 years of observations using the data from four antenna sites. The analysis of the elevation dependence of averaged multipath errors and the multipath time series for static data indicate significant suppression of long-range multipath by the best Galileo codes. The E5AltBOC signal is confirmed to be a multipath suppression champion for all the data sets. According to the results of the observations, the Galileo signals can be classified into 3 groups: high-performance (E5AltBOC, L1A, E6A, medium-performance (E6BC, E5a, E5b and an L1BC signal, which has the lowest performance among Galileo signals, but is still better than GPS-CA. The car tests have demonstrated that for kinematic multipath the intersignal differences are a lot less pronounced. The phase multipath performance is also discussed.

  6. Sexually transmitted diphtheria.

    Science.gov (United States)

    Berger, Anja; Lensing, Carmen; Konrad, Regina; Huber, Ingrid; Hogardt, Michael; Sing, Andreas

    2013-03-01

    Diphtheria is caused by diphtheria toxin-producing Corynebacterium species. While classical respiratory diphtheria is transmitted by droplets, cutaneous diphtheria often results from minor trauma. This report concerns the first case of sexually transmitted diphtheria in a patient with non-gonococcal urethritis after orogenital contact.

  7. Sexually transmitted infections

    African Journals Online (AJOL)

    AJRH Managing Editor

    treatment practices of sexually transmitted infections among brothel based female sex workers Three hundred and twenty three consenting ... five top diseases for which Nigerians seek medical ... in other countries have also revealed a high.

  8. Sexually Transmitted Diseases

    Science.gov (United States)

    Sexually transmitted diseases (STDs) are infections that are passed from one person to another through sexual contact. The causes of STDs ... often help with the symptoms and keep the disease under control. Correct usage of latex condoms greatly ...

  9. Sexually transmitted infections.

    Science.gov (United States)

    Fuchs, Wolfgang; Brockmeyer, Norbert H

    2014-06-01

    In no other medical field former rare infections of the 1980(th) and 1990(th) occur again as this is seen in the field of venerology which is as well based on the mobility of the population. Increasing rates of infections in Europe, and increasing bacteriological resistances face health professionals with new challenges. The WHO estimates more than 340 million cases of illnesses worldwide every year. Diseases caused by sexually transmitted infections (STI) in a strict sense are syphilis, gonorrhea, lymphogranuloma venereum, granuloma inguinale, and chancroid. In a wider sense, all illnesses are included which can mainly be transmitted through sexual contact. The term "sexual contact" has to be seen widely, from close physical contact to all variants of sexual behavior. This CME article is an overview of the most common occurring sexually transmitted infections in clinical practice. Both, basic knowledge as well as recent developments are discussed below.

  10. 卫星教学资源通过城域网传输的方案与实现%Project of Transmitting Satellite Video Teaching Resources through Metropolitan Area Network

    Institute of Scientific and Technical Information of China (English)

    薛曼芳

    2012-01-01

      The paper discusses how to use streaming media technology, satellite reception technology and existing computer, network, software and hardware resources to achieve efficient transmission, sharing and centralized management of satellite video teaching resource via Metropolitan Area Network (MAN). This project addresses the issues including uneven allocation of educational resources, difficulties in equipment management and shortage of IT supporting professionals during the implementation process of modern remote educational project of elementary and middle school in countryside. It also improves the level of information technology of education.%  探讨了如何利用流媒体技术、卫星接收技术及现有电脑网络软硬件资源,实现卫星视频教学资源在城域网内的有效传输、分享和集中管理,解决在“农村中小学现代远程教育工程”实施过程中,教育资源分配不均衡、资源和设备管理难、专业信息人员缺乏等问题,提高了教育信息化水平。

  11. [Sexually transmitted infections].

    Science.gov (United States)

    De Toni, T; Fontana, I

    2002-12-01

    Sexually transmitted diseases (STD) are quite common and observed more frequently in teens. The adolescents represent a group at particular risk for STD due to biological, sociocultural and psychological factors. Undectected infections may lead to unwanted sequelae, including pelvic inflammatory disease, chronic abdominal pain, tubal scarring and increased risk of ectopic pregnancy. This paper deals with infections by Candida albicans, Chlamidia tracomatis, Neisseria gonorrheae, Gardnerella vaginalis, Treponema pallidum, Tricomonas vaginalis, Herpes simplex, Papilloma virus. In regard to gonorrhea, chlamydia, syphilis and papilloma virus, the expectation is that improved detection will decrease sequelae by early diagnosis and treatment. Prevention programs (information, use of hormonal contraception associated with condom use) and improved access to STD diagnosis and treatment services are useful to reduce the incidence of STD among young people.

  12. Normal transmitting boundary conditions

    Institute of Scientific and Technical Information of China (English)

    廖振鹏

    1996-01-01

    The multi-transmitting formula (MTF) governed by a single artificial speed is analytically developed into a generalized MTF governed by a few artificial speeds to improve its capacity in simultaneous simulation of several one-way waves propagating at different speeds.The generalized MTF is then discretized and further generalized using the space extrapolation to improve its accuracies in numerical simulation of transient waves at large angles of incidence.The above two successive generalizitions of MTF based on the notion of normal transmission lead to a compact formula of local non-reflecting boundary condition.The formula not only provides a general representation of the major schemes of existing local boundary conditions but can be used to generate new schemes,which combine advantages of different schemes.

  13. Sexually transmitted proctitis

    Directory of Open Access Journals (Sweden)

    Sidney Roberto Nadal

    2012-03-01

    Full Text Available Proctitis caused by sexually transmitted agents is usually taken for inflammatory bowel diseases, because of similar complaints, such as pain, bleeding and mucopurulent discharge, as well as the histopathology. Thus, its treatment is postponed and, sometimes, complications appear. The most common etiologic agents are Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum and Herpes simplex. In order to avoid dissemination and complications, laboratory tests are essential for diagnosis and proper therapy. The objective of this article was to raise awareness to sexually transmitted diseases in proctitis etiology, as well as their diagnosis and treatment.As retites provocadas por agentes sexualmente transmissíveis são frequentemente confundidas com doenças inflamatórias intestinais, uma vez que as queixas mais comuns, que incluem dor, sangramento e secreção mucopurulenta, e o padrão histopatológico são semelhantes. Dessa maneira, o tratamento é postergado e, algumas vezes, as complicações aparecem. Os agentes mais comuns incluem a Neisseria gonorrhoeae, a Chlamydia trachomatis, o Treponema pallidum e o Herpes simplex. Exames laboratoriais sensíveis e específicos para confirmação diagnóstica são essenciais para o tratamento correto, evitando a disseminação e as sequelas. O objetivo deste artigo foi chamar a atenção para as doenças sexualmente transmissíveis na etiologia das retites, bem como seu diagnóstico e tratamento.

  14. A low cost data logging system with satellite transmission capabilities

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; DeSa, E.J.; Desai, R.G.P.

    satellite navigator, deep sea echosounder, and a magnetometer on board a chartered research vessel. A novel data logger design was implemented with the extra option of transmitting logged data through the ships INMARSAT approved satellite terminal...

  15. Sexually Transmitted Infections

    Directory of Open Access Journals (Sweden)

    LE Nicolle

    2005-01-01

    Full Text Available Sexually transmitted infections (STIs other than HIV have reappeared as an important public health problem in developed countries (1. In the late 1970s and early 1980s, research and treatment of the 'classic' STIs - gonorrhea, syphilis and chlamydia - were a major focus of infectious diseases practice and research. There were large outbreaks of syphilis in parts of Canada (2, penicillin-resistant Neisseria gonorrhoeae was a concern (3, and high rates of Chlamydia trachomatis infection with complications of pelvic inflammatory disease and ectopic pregnancy were being reported (4,5. Then, HIV infection emerged, with its spectre of a wasting, early death. There was no effective treatment, and safe sexual practices were embraced and adhered to by high-risk populations as the only effective way to avoid infection. These practices effectively prevented other STIs; rates of syphilis, gonorrhea and chlamydia infection plummeted in developed countries (5. For at least a decade, it appeared that HIV might be an end to all STIs, at least for some parts of the world. STIs continued unabated in developing countries, as many epidemiological and therapeutic studies explored the association of STIs with HIV infection.

  16. Medications for Sexually Transmitted Infections

    Science.gov (United States)

    ... Genitals and Urinary Tract Glands & Growth Head Neck & Nervous System Heart Infections Learning Disabilities Obesity Orthopedic Prevention Sexually Transmitted Skin Tobacco Treatments Injuries & ...

  17. 47 CFR 25.220 - Non-conforming transmit/receive earth station operations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Non-conforming transmit/receive earth station... CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.220 Non-conforming transmit/receive... operator acknowledging that the proposed operation of the subject non-conforming earth station with...

  18. Microwave power transmitting phased array antenna research project

    Science.gov (United States)

    Dickinson, R. M.

    1978-01-01

    An initial design study and the development results of an S band RF power transmitting phased array antenna experiment system are presented. The array was to be designed, constructed and instrumented to permit wireless power transmission technology evaluation measurements. The planned measurements were to provide data relative to the achievable performance in the state of the art of flexible surface, retrodirective arrays, as a step in technically evaluating the satellite power system concept for importing to earth, via microwave beams, the nearly continuous solar power available in geosynchronous orbit. Details of the microwave power transmitting phased array design, instrumentation approaches, system block diagrams, and measured component and breadboard characteristics achieved are presented.

  19. Transfusion-transmitted Chagas' disease.

    Science.gov (United States)

    Wendel, S

    1998-11-01

    Transfusion-transmitted Chagas' disease has been recognized since 1952. Until recently, no cases were reported outside of Latin America. However, emigration during the past 20 years expanded its transfusional geographic borders to North America. Trypanosoma cruzi-infected donors usually are asymptomatic, often for a lifetime. This situation complicates donor screening, particularly in regions where blood bank personnel are not familiar with the risk factors and natural history of this transfusion-transmitted infection. This review addresses the main aspects of epidemiology, risks of infection, clinical symptoms in donors and recipients, preventive measures, and blood donor screening to prevent transfusion-transmitted Chagas' disease.

  20. Statistics, Uncertainty, and Transmitted Variation

    Energy Technology Data Exchange (ETDEWEB)

    Wendelberger, Joanne Roth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-05

    The field of Statistics provides methods for modeling and understanding data and making decisions in the presence of uncertainty. When examining response functions, variation present in the input variables will be transmitted via the response function to the output variables. This phenomenon can potentially have significant impacts on the uncertainty associated with results from subsequent analysis. This presentation will examine the concept of transmitted variation, its impact on designed experiments, and a method for identifying and estimating sources of transmitted variation in certain settings.

  1. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  2. Satellite virtual atomic clock with pseudorange difference function

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Satellite atomic clocks are the basis of GPS for the control of time and frequency of navigation signals. In the Chinese Area Positioning System (CAPS), a satellite navigation system without the satellite atomic clocks onboard is successfully developed. Thus, the method of time synchronization based on satellite atomic clocks in GPS is not suitable. Satellite virtual atomic clocks are used to implement satellite navigation. With the satellite virtual atomic clocks, the time at which the signals are transmitted from the ground can be delayed into the time that the signals are transmitted from the satellites and the pseudorange measuring can be fulfilled as in GPS. Satellite virtual atomic clocks can implement the navigation, make a pseudorange difference, remove the ephemeris error, and improve the accuracy of navigation positioning. They not only provide a navigation system without satellite clocks, but also a navigation system with pseudorange difference.

  3. Transfusional transmitted viruses in pregnancy.

    Science.gov (United States)

    Eleftheriou, A; Kalakoutis, G; Pavlides, N

    1998-01-01

    Blood has long been recognized as a vehicle for transmission of infectious organisms and as molecular laboratory technology has advanced, a seemingly endless array of infectious agents has occasionally been documented to be blood transmitted. Transfusion associated hepatitis (TAH) has been the most common serious consequence of blood transfusion although in recent years this has been significantly reduced (blood donor screening, blood processing, etc.). Thalassaemia major is classically associated with increased susceptibility to infections caused by those agents that are blood transmitted such as HBV, HCV, HIV, CMV, HPV B-19 (frequency rates vary from country to country). Monitoring the prevalence of transfusion transmitted infections in thalassaemics has been in recent years an indispensable part of their clinical management protocol. As a number of these viruses have been documented to be efficiently transmitted through the vertical route, the issue of blood transmitted viral infection monitoring becomes particularly important in order to provide protection or treatment both to the pregnant thalassaemic patient herself and to her foetus/newborn. Hepatitis (mainly B and C) and HIV in the obstetric thalassaemic is what the clinician is faced with most frequently. Although preventative measures have been very successful in the case of HBV infection and recently to an encouraging extent in the case of HIV (recommendations have been constructed), the mechanisms and frequency of HCV vertical transmission as well as the clinical outcome of children born to HCV carriers are not yet completely clarified. No vaccines are available and HIGB or antivirals do not appear to offer protection to the foetus against infection with HCV. Thalassaemics are frequently seropositive to markers of other transfusion transmitted viruses, such as CMV and HPV B-19, particularly by the age of pregnancy. Infection with a second or multiple strains as well as reactivation of existing CMV

  4. Inexpensive land-use maps extracted from satellite data

    Science.gov (United States)

    Barney, T. W.; Barr, D. J.; Elifrits, C. D.; Johannsen, C. J.

    1979-01-01

    Satellite images are interpretable with minimal skill and equipment by employing method which uses false color composite print of image of area transmitted from Landsat satellite. Method is effective for those who have little experience with satellite imagery, little time, and little money available.

  5. Sexually transmitted diseases and anorectum.

    OpenAIRE

    VAN KEMSEKE, Catherine

    2009-01-01

    Sexually transmitted diseases (STD) are a major public health problem because their incidence is increasing worldwide despite prevention campaigns and because they raise the risk of HIV infection. Anorectal localisations of STD are common among men who have sex with men (MSM) but can also be seen among heterosexuals (men or women). Transmission of such infections is due to anal sex or to other sexual behaviours like "fisting". Although some pathogens (like Human Papillomavirus-HPV) are common...

  6. Zika Mosquito Can Transmit Other Viruses, Too

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_165752.html Zika Mosquito Can Transmit Other Viruses, Too 3-in- ... mosquito species that's the main carrier of the Zika virus might also transmit two other viruses -- chikungunya ...

  7. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  8. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  9. Group delay variations of GPS transmitting and receiving antennas

    Science.gov (United States)

    Wanninger, Lambert; Sumaya, Hael; Beer, Susanne

    2017-09-01

    GPS code pseudorange measurements exhibit group delay variations at the transmitting and the receiving antenna. We calibrated C1 and P2 delay variations with respect to dual-frequency carrier phase observations and obtained nadir-dependent corrections for 32 satellites of the GPS constellation in early 2015 as well as elevation-dependent corrections for 13 receiving antenna models. The combined delay variations reach up to 1.0 m (3.3 ns) in the ionosphere-free linear combination for specific pairs of satellite and receiving antennas. Applying these corrections to the code measurements improves code/carrier single-frequency precise point positioning, ambiguity fixing based on the Melbourne-Wübbena linear combination, and determination of ionospheric total electron content. It also affects fractional cycle biases and differential code biases.

  10. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  11. Update on the Solar Power Satellite transmitter design

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.C.

    1986-01-01

    A number of remaining problems in the conceptual design of the transmitting antenna for the Solar Power Satellite have been solved as a result of additional technology development. Much of the technology was derived from the conceptual design of a ground-based transmitting antenna for beaming power to a high altitude airship or airplane.

  12. Notification of transfusion transmitted infection.

    Science.gov (United States)

    Choudhury, Lincoln P; Tetali, Shailaja

    2008-01-01

    The National Blood Policy of India, 2002, advocates the disclosure of results of transfusion transmitted infections (TTI) to blood donors. However, in the absence of well-defined notification processes, and in order to avoid serious consequences resulting from unguided disclosure, blood bank personnel discard blood that is TTI-positive. We report on a survey of 105 voluntary blood donors in Kerala. Only two out of three participants had filled the donor form in the last year. Only half were aware that the blood bank was supposed to inform them if they tested positive for TTI. Fifty-seven per cent of donors wanted to be informed every time they donated blood, irrespective of a positive or negative result.

  13. Transfusion-transmitted parasitic infections

    Directory of Open Access Journals (Sweden)

    Singh Gagandeep

    2010-01-01

    Full Text Available The transmission of parasitic organisms through transfusion is relatively rare. Of the major transfusion-transmitted diseases, malaria is a major cause of TTIP in tropical countries whereas babesiosis and Chagas′ disease pose the greatest threat to donors in the USA In both cases, this is due to the increased number of potentially infected donors. There are no reliable serologic tests available to screen donors for any of these organisms and the focus for prevention remains on adherence to donor screening guidelines that address travel history and previous infection with the etiologic agent. One goal is the development of tests that are able to screen for and identify donors potentially infectious for parasitic infections without causing the deferral of a large number of non-infectious donors or significantly increasing costs. Ideally, methods to inactivate the infectious organism will provide an element of added safety to the blood supply.

  14. Communications via the radio artificial earth satellite: Design of the tracking diagram and features for conducting QSO

    Science.gov (United States)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

    A detailed examination is made of the operation of a transmitting artifical Earth satellite. A tracking diagram for the satellite is constructed. The zone of radio visibility can be determined based on the techniques proposed.

  15. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  16. Sexually Transmitted Infections in Tehran

    Directory of Open Access Journals (Sweden)

    Maryam Afrakhteh

    2008-09-01

    Full Text Available Objective: Sexually transmitted infections (STIs remain a public health problem of major significance in most parts of the world. This study aimed to detect the most prevalent pathogens in patients with signs and symptoms of STI referring to a group of university clinics in Tehran.Materials and methods: In this cross-sectional study using randomized cluster sampling, 507 consecutive male and female patients presenting with signs and symptoms of STI referring to selected health care centers of Shahid Beheshti University were evaluated between May 2005 and May 2007. Diagnosis was made according to WHO criteria for signs and symptoms of STI in addition to microscopic study of genital discharges. Results: The most prevalent STI pathogens were Candida, Trichomona, Neisseria gonorrhoeae and Chlamydia with respective frequencies of 53.96%, 18.87%, 4.91% and 22.26% in women and 47.10%, 8.67%, 9.50% and 34.71% in men.Conclusion: Candida was detected in majority of cases. Chlamydia was the most prevalent STI in both sexes. Simple preventive care has crucial role in decreasing the frequency of STIs in society.

  17. Recessively transmitted predominantly motor neuropathies.

    Science.gov (United States)

    Parman, Yeşim; Battaloğlu, Esra

    2013-01-01

    Recessively transmitted predominantly motor neuropathies are rare and show a severe phenotype. They are frequently observed in populations with a high rate of consanguineous marriages. At least 15 genes and six loci have been found to be associated with autosomal recessive CMT (AR-CMT) and X-linked CMT (AR-CMTX) and also distal hereditary motor neuronopathy (AR-dHMN). These disorders are genetically heterogeneous but the clinical phenotype is relatively homogeneous. Distal muscle weakness and atrophy predominating in the lower extremities, diminished or absent deep tendon reflexes, distal sensory loss, and pes cavus are the main clinical features of this disorder with occasional cranial nerve involvement. Although genetic diagnosis of some of subtypes of AR-CMT are now available, rapid advances in the molecular genetics and cell biology show a great complexity. Animal models for the most common subtypes of human AR-CMT disease provide clues for understanding the pathogenesis of CMT and also help to reveal possible treatment strategies of inherited neuropathies. This chapter highlights the clinical features and the recent genetic and biological findings in these disorders based on the current classification.

  18. Zoonosis that is Transmitted Through Food

    OpenAIRE

    Tri Budhi Murdiati; Indrawati Sendow

    2006-01-01

    Zoonosis can be transmitted through a number of routes including food of animal products . Foodborne disease is a disease transmitted through food, while zoonosis is defined as a disease that can be transmitted from animal to man or vice versa . Then, if agent in foodborne disease is a zoonotic, it could be defined as foodborne zoonosis . The outbreaks of Bovine Spongioform Encephalopathy (BSE) followed by Avian influenza (AI) have caused increasing concern in the food safety of animal produc...

  19. USACE AIS Transmit Technical Support Summary Report

    Science.gov (United States)

    2014-09-01

    USACE AIS Transmit Technical Support Summary Report Distribution Statement A: Approved for public release; distribution is unlimited...September 2014 Report No. CD-D-09-15 USACE AIS Transmit Technical Support Summary Report ii UNCLAS//Public | CG-926 RDC | I. Gonin et al. Public...States Coast Guard Research & Development Center 1 Chelsea Street New London, CT 06320 USACE AIS Transmit Technical Support Summary Report

  20. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  1. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  2. Videoconferencing via satellite. Opening Congress to the people: Technical report

    Science.gov (United States)

    Wood, F. B.; Coates, V. T.; Chartrand, R. L.; Ericson, R. F.

    1978-01-01

    The feasibility of using satellite videoconferencing as a mechanism for informed dialogue between Congressmen and constituents to strengthen the legislative process was evaluated. Satellite videoconferencing was defined as a two-way interactive television with the TV signals transmitted by satellite. With videoconferencing, one or more Congressmen in Washington, D. C. can see, hear and talk with groups of citizens at distant locations around the country. Simultaneously, the citizens can see, hear and talk with the Congressmen.

  3. Research Supporting Satellite Communications Technology

    Science.gov (United States)

    Horan Stephen; Lyman, Raphael

    2005-01-01

    This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

  4. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  5. The power relay satellite

    Science.gov (United States)

    Glaser, Peter E.

    The availability and use of renewable energy sources compatible with reducing risks to the global environment are key to sustainable development. Large-scale, renewable energy resources at undeveloped or underutilized sites are potentially available on several continents. The Power Relay Satellite (PRS) concept has the potential to access these remote energy resources by coupling primary electricity generation from terrestrial transmission lines. A global PRS network can be envisioned to provide a high degree of flexibility for supplying energy demands worldwide with wireless power transmitted from sites on Earth to geosynchronous orbit and then reflected to receivers interfacing with terrestrial power transmision networks. Past developments in wireless power transmission (WPT) are reviewed and recent successful results are noted. The origins of the PRS concept, and a possible configuration are discussed, principles of WPT at microwave frequencies, functional requirements, and system design contraints are outlined, and space transportation concepts presented. PRS assessments including applicable technologies, economic projections, and societal issues are highlighted. It is concluded that the PRS provides a promising option to access renewable resources at great distances from major markets, and represents an important stage in the future development in the future of solar power satellites.

  6. GNSS信号接收机的构件初识──GNSS导航信号的收发问题之十%The Current Status and Development on Reifning GNSS Ephemeris by Means of Satellite Laser Ranging--Transmitting/receiving Issue(10) of GNSS Navigation Signals

    Institute of Scientific and Technical Information of China (English)

    刘基余

    2015-01-01

    The GNSS signal receiver is GNSS user equipment for satellite navigation and the terminal equipment for realizing GNSS satellite navigation/positioning. It is the radio receiving equipment that is able to receive, process, track and measure the GNSS navigation signals. It has not only the common performance of the radio receiving equipments, but also the characteristic performance for acquiring, tracking and surveying the weak satellite signals of 3.5E-16W~2.5E-17W. For this reason the structural components of GNSS signal receivers must meet the needs to capture, track, and measure the GNSS signals.%GNSS信号接收机是GNSS导航卫星的用户设备,是实现GNSS卫星导航定位的终端仪器。它是一种能够接收、跟踪、变换和测量GNSS卫星导航定位信号的无线电接收设备,既具有常用无线电接收设备的共性,又具有捕获、跟踪和处理弱达3.5E-16W~2.5E-17W卫星微弱信号的特性。为此,GNSS信号接收机的构件必须满足这种捕获、跟踪和测量GNSS信号的需求。

  7. Parasitic diseases in humans transmitted by vectors.

    Science.gov (United States)

    Cholewiński, Marcin; Derda, Monika; Hadaś, Edward

    2015-01-01

    Despite the considerable progress of medicine, parasitic diseases still pose a great threat to human health and life. Among parasitic diseases, those transmitted by vectors, mainly arthropods, play a particular role. These diseases occur most frequently in the poorest countries and affect a vast part of the human population. They include malaria, babesiosis, trypanosomiasis, leishmaniasis and filariasis. This study presents those vector-transmitted diseases that are responsible for the greatest incidence and mortality of people on a global scale. Attention is focused primarily on diseases transmitted by mosquitoes, flies, Hemiptera and ticks.

  8. Selection of satellite constellation framework of CAPS

    Institute of Scientific and Technical Information of China (English)

    HAN YanBen; MA LiHua; QIAO QiYuan; YIN ZhiQiang; AI GuoXiang

    2009-01-01

    Based on the idea of transmitting the satellite navigation and positioning system,taking the distribution and variation of the Position Dilution of Precision factor (PDOP),which is closely related with the precision of navigation and positioning,within the China area as the primary criterion,we analyze and discuss the tentative plan of constellation configuration consisting of geosynchronous orbit (GEO) communication satellites and inclined geosynchronous orbit (IGSO) satellites for the transmitting Chinese Area Positioning System (CAPS).We emphatically consider the effect on the PDOP by the three major orbit parameters including the inclination,eccentricity and right ascension of the ascending node (RAAN) of IGSO satellites,to research the strategies of the constellation configuration of CAPS through software emulation.Various constellation configurations are analyzed and compared and the results show that the constellation configuration,consisting of three IGSO communication satellites in three orbits with the same inclination as 50°,the difference in RAAN as 120°and the same "8" shaped ground track centered near 115°E and four or five GEO communication satellites within 60°E to 150°E,can satisfy the requirement that Chinese domain is availably covered end the navigation and positioning with high precision could be obtained.Three relatively excellent constellation configurations are initially suggested and some concerned issues are discussed in this work.

  9. Selection of satellite constellation framework of CAPS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the idea of transmitting the satellite navigation and positioning system, taking the distribution and variation of the Position Dilution of Precision factor (PDOP), which is closely related with the precision of navigation and positioning, within the China area as the primary criterion, we analyze and discuss the tentative plan of constellation configuration consisting of geosynchronous orbit (GEO) communication satellites and inclined geosynchronous orbit (IGSO) satellites for the transmitting Chinese Area Positioning System (CAPS). We emphatically consider the effect on the PDOP by the three major orbit parameters including the inclination, eccentricity and right ascension of the ascend- ing node (RAAN) of IGSO satellites, to research the strategies of the constellation configuration of CAPS through software emulation. Various constellation configurations are analyzed and compared and the results show that the constellation configuration, consisting of three IGSO communication satellites in three orbits with the same inclination as 50°, the difference in RAAN as 120° and the same "8" shaped ground track centered near 115°E and four or five GEO communication satellites within 60°E to 150°E, can satisfy the requirement that Chinese domain is availably covered and the navigation and positioning with high precision could be obtained. Three relatively excellent constellation configurations are initially suggested and some concerned issues are discussed in this work.

  10. CDC WONDER: Sexually Transmitted Disease (STD) Morbidity

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Sexually Transmitted Disease (STD) Morbidity online databases on CDC WONDER contain case reports reported from the 50 United States and D.C., Puerto Rico, Virgin...

  11. CDC WONDER: Sexually Transmitted Disease (STD) morbidity

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Sexually Transmitted Disease (STD) Morbidity online databases on CDC WONDER contain case reports reported from the 50 United States and D.C., Puerto Rico, Virgin...

  12. syndromic management of sexually transmitted infections

    African Journals Online (AJOL)

    Kurt

    infectious disease service delivery. He has led ... referred to as classic sexually transmitted infections (STIs). ... chomoniasis) occur every year in developing countries.2 In South ... motion of STI prevention is often absent (most patients did not.

  13. Clinical update in sexually transmitted diseases-2014.

    Science.gov (United States)

    Fanfair, Robyn Neblett; Workowski, Kimberly A

    2014-02-01

    Sexually transmitted diseases (STDs) and their associated syndromes are extremely common in clinical practice. Early diagnosis, appropriate treatment, and partner management are important to ensure sexual, physical, and reproductive health in our patients.

  14. Sexually Transmitted Diseases: Teens at Risk.

    Science.gov (United States)

    Mascola, Laurene

    1987-01-01

    Parents of preteens need to be aware of the rapidly increasing incidence of sexually transmitted diseases among teenagers and to begin talking to their preteens to help prevent or modify risky sexual experimentation during middle adolescence. (MT)

  15. Transmitting boundary and radiation conditions at infinity

    Institute of Scientific and Technical Information of China (English)

    廖振鹏

    2001-01-01

    Relationship between the radiation conditions at infinity and the transmitting boundary for numerical simulation of the near-field wave motion has been studied in this paper. The conclusion is that the transmitting boundary is approximately equivalent to the radiation conditions at infinity for a large class of infinite media. And the errors of the approximation are of the same order of magnitude as those of the finite elements or finite differences in numerical simulation of wave motion. This result provides a sound theoretical basis for the transmitting boundary used in the numerical simulation of the near-field wave motion and gives a complete explanation for the major experiences accumulated in applications of the transmitting boundary to the numerical simulation.

  16. Vulnerability and Knowledge of Sexually Transmitted Infections ...

    African Journals Online (AJOL)

    hanumantp

    common causes of illness world-wide with far reaching health, ... Keywords: Enugu, Female traders, Knowledge, Prevention, Sexually transmitted infections, Vulnerability. Original ... constituted the work force, especially in developing countries.

  17. Knowledge of Sexually Transmitted Diseases among Secondary ...

    African Journals Online (AJOL)

    KeyWords: Sexually transmitted diseases, Adolescent, Knowledge, Information, ... AIDS is relatively low when compared to other locations in the country. ... be as a result of inadequate diagnostic and treatment facilities in the rural areas fear of.

  18. Tackling sexually transmitted infection burden in Ugandan ...

    African Journals Online (AJOL)

    Background: Despite being in a different country and social environment, Ugandans living in ... Keywords:sexually transmitted infection, Ugandan communities, .... their prevention to enable control programs take root. Methods. This study used ...

  19. Knowledge of sexually transmitted diseases among secondary ...

    African Journals Online (AJOL)

    Knowledge of sexually transmitted diseases among secondary school students in ... prevent the diseases among adolescent populations in developing countries. ... simple random sampling and stratified sampling methods was used to select ...

  20. Concept design of HAYATE : Small satellite for supporting Antarctic geophysical observation

    OpenAIRE

    Yoshihara, Keisuke; Sugiura, Yoshiki; Sekiguchi,Masato; Ui, Kyoichi; Tsurumi,Singo; Nakaya, Koji; Mori, Makoto; Matsunaga, Saburo; Ohkami, Yoshiaki

    1999-01-01

    This paper presents the results of conceptual design of a small communication satellite (HAYATE) for supporting research in Antarctica and remote islands. The HAY ATE satellite collects environmental data from unmanned probes located on the Antarctic ice plate and also transmits data from Syowa Station in Antarctica to Japan and the United States. Through the satellite mission analyses, we confirmed that the HAYATE satellite would be able to gather data for GPS baseline analysis and to observ...

  1. Perceptions of sexually transmitted diseases among teenagers

    Directory of Open Access Journals (Sweden)

    DM Diale

    2000-09-01

    Full Text Available An ex p lo ra to ry d e sc rip tiv e study was u n d e rtak en , focussing on sexually transmitted diseases (STD among teenagers. The aim of the study was to explore and describe the possible reasons for the high rate of sexually transmitted diseases in teenagers. The perceptions of teenagers and community nurses regarding sexually transmitted disease among teenagers involved in the teenage clinic in a specific predominantly black area were assessed. Twenty teenagers and five community nurses were participants in the study. Two focus group interviews were conducted with teenagers and community nurses. It can be concluded that the attitudes of community nurses may have an influence on the high rate of sexually transmitted diseases among teenagers. The knowledge o f the teenagers about sexually transmitted diseases is often based on myths and misconceptions which could be intensified by the community nurse. The recommendations made are that the education standards of all community nurses should be reviewed and adapted to meet the needs of teenagers attending the teenage health services. The policy on in-service training must be reviewed and monitored. Community nurses’ intensive training on teenage health service delivery and sexually transmitted diseases services should be in accordance with the principles of Primary Health Care. Community nurses need to attend intensive courses on interpersonal skills specifically related to teenagers. Selection procedures for recruiting community nurses to attend to teenagers specifically should be researched. Teenagers should be involved in planning programs and the teenage clinic should be evaluated frequently to improve the standards. The availability of adequate teenage health services can result in a decrease in sexually transmitted diseases among teenagers.

  2. The Omninet mobile satellite system

    Science.gov (United States)

    Salmasi, A.; Curry, W.

    Mobile Satellite System (MSS) design offering relatively low cost voice, data, and position location services to nonmetropolitan areas of North America is proposed. The system provides spectrally efficient multiple access and modulation techniques, and flexible user interconnection to public and private switched networks. Separate UHF and L-band satellites employing two 9.1 m unfurlable antennas each, achieve a 6048 channel capacity and utilize spot beams. Mobile terminals have modular design and employ 5 dBi omnidirectional antennas. Gateway stations (with two 5 m Ku-band antennas) and base stations (with a single 1.8 m Ku-band antenna) transmit terrestrial traffic to the satellite, where traffic is then transponded via an L-band or UHF downlink to mobile users. The Network Management Center uses two 5-m antennas and incorporates the Integrated-Adaptive Mobile Access Protocol to assure demand assignment of satellite capacity. Preliminary implementation of this low-risk system involves a mobile alphanumeric data service employing receive-only terminals at Ku-band projected for 1987, and plans for the launching of L-band receive-only packages as early as 1988.

  3. Adaptive transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-01-01

    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  4. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  5. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  6. Space Solar Power Satellite Systems, Modern Small Satellites, and Space Rectenna

    Science.gov (United States)

    Bergsrud, Corey Alexis Marvin

    Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving "daughter" satellite sits inside a larger power transmitting "mother" satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware's for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first

  7. Syndromes Associated with Sexually Transmitted Infections

    Directory of Open Access Journals (Sweden)

    Max Chernesky

    2005-01-01

    Full Text Available Excellent technologies have been developed to identify the specific microbial agents of chlamydia, gonorrhea, syphilis, herpes, chancroid, trichomoniasis, human papillomavirus and HIV infection. However, it is also crucial to recognize syndromes that may be caused by one or more sexually transmitted pathogens. When laboratory services are lacking or are inadequate to provide timely results to enable appropriate treatment, some patients must be managed and treated syndromically. Most Canadian laboratories should be able to provide diagnostic services to determine the etiology of syndromes such as cervicitis, urethritis, pelvic inflammatory disease, prostatitis, genital ulcers, sexually transmitted infection (STI-related enteric infections, epididymitis, hepatitis, ophthalmia neonatorum, vulvovaginitis and vaginosis.

  8. Theory of experimental location of ionospheric inhomogeneities at medium latitudes by satellite radioholography

    Energy Technology Data Exchange (ETDEWEB)

    Dubovoi, A.P.; Sinelnikov, V.M.

    1980-08-01

    A theory is developed for a quasiholographic experiment which uses a differential-phase signal derived from radio signals transmitted at two coherent frequencies to obtain information on ionospheric inhomogeneities in a plane connecting the ground station and a part of the satellite orbit. The method makes it possible to determine the size and location of small-scale inhomogeneities with a radius of 100-500 m from ground-based measurements of spaced satellite signals transmitted at sufficiently high coherent frequencies.

  9. Advanced satellite communication system

    Science.gov (United States)

    Staples, Edward J.; Lie, Sen

    1992-01-01

    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  10. Temperature, pressure and light data collected by attached Archival Transmitting Tags to Salvelinus malma (Dolly Varden trout) in the Wulik River, Alaska, during 2012-06 to 2013-10 (NODC Accession 0119954)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains data collected by electronic tags (Pop-up Satellite Archival Transmitting) attached to Salvelinus malma (Dolly Varden trout) in the Wulik...

  11. Digital media and sexually transmitted infections.

    Science.gov (United States)

    Gilliam, Melissa; Chor, Julie; Hill, Brandon

    2014-10-01

    Digital media, including the Internet, social networking sites, text messaging, and mobile applications, are ubiquitous among adolescents and young adults. These platforms enable users to obtain important information on a multitude of health topics, they may facilitate risk-taking behaviors, and they can be key components of health interventions. The purpose of this article is to review the recent literature on digital media and sexually transmitted infections, discussing their role in potentiating and reducing risk. This review demonstrates adolescents' use of digital media to gather information on health topics and discusses significant privacy concerns regarding using media to explore sexual health information. Although several studies demonstrate an association between social media and increased sexual risk-taking behaviors, this relationship is not fully understood. Digital media-based interventions are increasingly being developed to either reduce risk or improve management of sexually transmitted infections. As greater numbers of adolescents use digital media, the potential for these platforms to influence sexual risk-taking behaviors is significant. Additional research is needed to better understand the impact of digital media on sexually transmitted infection risk and to develop social media-based interventions to improve sexually transmitted infection outcomes.

  12. Zoonosis that is Transmitted Through Food

    Directory of Open Access Journals (Sweden)

    Tri Budhi Murdiati

    2006-03-01

    Full Text Available Zoonosis can be transmitted through a number of routes including food of animal products . Foodborne disease is a disease transmitted through food, while zoonosis is defined as a disease that can be transmitted from animal to man or vice versa . Then, if agent in foodborne disease is a zoonotic, it could be defined as foodborne zoonosis . The outbreaks of Bovine Spongioform Encephalopathy (BSE followed by Avian influenza (AI have caused increasing concern in the food safety of animal products, especially after men were confirmed die from Al infection . Consumers are wondering whether the disease could be transmitted through the animal products from the infected animals . The safety of animal originated food is affected by the practices along the food chain, from farm to consumer plate . Human health hazard could enter the food at any points of the food chain . At the food preparation, some of the foodborne zoonosis can be prevented by the program of five keys for safer food, i .e. keep food clean, separate raw from cooked food, cook food thoroughly, store food at safe temperatures and use water and raw materials that are safe .

  13. Inductive Reasoning about Causally Transmitted Properties

    Science.gov (United States)

    Shafto, Patrick; Kemp, Charles; Bonawitz, Elizabeth Baraff; Coley, John D.; Tenenbaum, Joshua B.

    2008-01-01

    Different intuitive theories constrain and guide inferences in different contexts. Formalizing simple intuitive theories as probabilistic processes operating over structured representations, we present a new computational model of category-based induction about causally transmitted properties. A first experiment demonstrates undergraduates'…

  14. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  15. Design and analysis of the satellite laser communications network

    Science.gov (United States)

    Ren, Pei-an; Qian, Fengchen; Liu, Qiang; Jin, Linlin

    2015-02-01

    A satellite laser communications network structure with two layers and multiple domains has been proposed, which performance has been simulated by OPENT. To simulation, we design several OPNET models of the network's components based on a satellite constellation with two layers and multiple domains, as network model, node model, MAC layer protocol and optical antenna model. The network model consists of core layer and access layer. The core network consists of four geostationary orbit (GEO) satellites which are uniformly distributed in the geostationary orbit. The access network consists of 6 low Earth orbit (LEO) satellites which is the walker delta (walk-δ) constellation with three orbit planes. In access layer, each plane has two satellites, and the constellation is stably. The satellite constellation presented for space laser network can meet the demand of coverage in the middle and low latitude by a few satellites. Also several terminal device models such as the space laser transmitter, receiver, protocol layer module and optical antenna have been designed according to the inter-satellite links in different orbits t from GEO to LEO or GEO to ground. The influence to network of different transmitting throughput, receiving throughput, network protocol and average time delay are simulated. Simulation results of network coverage, connectivity and traffic load performance in different scenes show that the satellite laser network presented by the paper can be fit for high-speed satellite communications. Such analysis can provide effective reference for the research of satellite laser networking and communication protocol.

  16. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  17. Advances in understanding paternally transmitted Chromosomal Abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

  18. SEXUALLY TRANSMITTED DISEASES: INCIDENCE AND DISTRIBUTION

    Institute of Scientific and Technical Information of China (English)

    王千秋

    1996-01-01

    The incidence of sexually transmitted diseases(STDs) increased from 26. 04 per 10000O in 1987 to 104. 81 per 100 000 in 1993 in selected areas of the country. Gonorrhea is by far the most common STD but its constituent ratio declined because of a rapid increase of nongonococcal uretheritis and genital warts during most recent years. The incidence of syphilis is relatively low and cases of congenital infection are noted. The wide spread of resistant Neisseria gonorrhaeae infection gives a challenge to the therapeutical and control strategies of STDs. Sexually transmitted Chlamydia trachomatis infections, an important cause of urethritis, cervicitis and pelvic inflammatory disease, is becoming common in uur country. Attention has been drawn on viral hepatitis in their means of transmission by sexually behaviors, and also, on the homosexuals, assumed to be the high risk group to catch STDs. Coordinated national efforts to control STDs in China have been taken.

  19. Syndromes Associated with Sexually Transmitted Infections

    OpenAIRE

    Max Chernesky; David Patrick; Rosanna Peeling

    2005-01-01

    Excellent technologies have been developed to identify the specific microbial agents of chlamydia, gonorrhea, syphilis, herpes, chancroid, trichomoniasis, human papillomavirus and HIV infection. However, it is also crucial to recognize syndromes that may be caused by one or more sexually transmitted pathogens. When laboratory services are lacking or are inadequate to provide timely results to enable appropriate treatment, some patients must be managed and treated syndromically. Most Canadian ...

  20. Molecular Diagnostics for Soil-Transmitted Helminths

    OpenAIRE

    O'Connell, Elise M.; Nutman, Thomas B.

    2016-01-01

    Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and Ascaris lumbricoides) has relied on often-insensitive microscopy techniques. Over the past several years, there has been an effort to use molecular diagnostics, particularly quantitative polymerase chain reaction (qPCR), to detect intestinal pathogens. While some platforms have been approved by regulatory bodies (e.g., Food and ...

  1. Black currant reversion virus, a mite-transmitted nepovirus.

    Science.gov (United States)

    Susi, Petri

    2004-05-01

    SUMMARY Taxonomy: Black currant reversion virus (BRV) is the first identified mite-transmitted member of the genus Nepovirus (family Comoviridae). A few systematic studies have been performed to compare virus isolates from different geographical locations. Physical properties: Purified preparations contain two closely sedimenting centrifugal components (B and M for RNA1 and RNA2, respectively) at varying ratios, and occasionally a T component (for satellite RNA). The BRV capsids have a diameter of 27 nm and they are putatively composed of 60 copies of a single species of capsid (coat) protein assembled in an icosahedral lattice. Diluted plant sap loses its infectivity within 1 day at 20 degrees C and in 4-8 days at 4 degrees C. Hosts: The natural host range of BRV is limited; it infects black currant (Ribes nigrum L.) and some related Ribes species. The transmission of the virus is by the eriophyid gall mite of black currant (Cecidophyopsis ribis). A number of herbaceous plants can be infected experimentally. BRV is the agent of black currant reversion disease (BRD), which is economically the most significant virus disease in Ribes species. BRV and BRD occur widely in locations where black currant is cultivated commercially.

  2. ERROR-CONTROL CODING OF ADS-B MESSAGES FOR IRIDIUM SATELLITES

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2013-12-01

    Full Text Available For modelling of ADS-B messages transmitting on the base of low-orbit satellite constellation Іrіdіum the model of a communication channel “Aircraft - Satellite - Ground Station” was built using MATLAB Sіmulіnk. This model allowed to investigate dependences of the Bit Error Rate on a type of  signal coding/decoding, ratio Eb/N0 and satellite repeater gain

  3. Satellite data compression

    CERN Document Server

    Huang, Bormin

    2011-01-01

    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  4. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  5. Laser Communication Experiments with Artemis Satellite

    Science.gov (United States)

    Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

    2013-10-01

    In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and

  6. Stochastic dynamics for reinfection by transmitted diseases

    Science.gov (United States)

    Barros, Alessandro S.; Pinho, Suani T. R.

    2017-06-01

    The use of stochastic models to study the dynamics of infectious diseases is an important tool to understand the epidemiological process. For several directly transmitted diseases, reinfection is a relevant process, which can be expressed by endogenous reactivation of the pathogen or by exogenous reinfection due to direct contact with an infected individual (with smaller reinfection rate σ β than infection rate β ). In this paper, we examine the stochastic susceptible, infected, recovered, infected (SIRI) model simulating the endogenous reactivation by a spontaneous reaction, while exogenous reinfection by a catalytic reaction. Analyzing the mean-field approximations of a site and pairs of sites, and Monte Carlo (MC) simulations for the particular case of exogenous reinfection, we obtained continuous phase transitions involving endemic, epidemic, and no transmission phases for the simple approach; the approach of pairs is better to describe the phase transition from endemic phase (susceptible, infected, susceptible (SIS)-like model) to epidemic phase (susceptible, infected, and removed or recovered (SIR)-like model) considering the comparison with MC results; the reinfection increases the peaks of outbreaks until the system reaches endemic phase. For the particular case of endogenous reactivation, the approach of pairs leads to a continuous phase transition from endemic phase (SIS-like model) to no transmission phase. Finally, there is no phase transition when both effects are taken into account. We hope the results of this study can be generalized for the susceptible, exposed, infected, and removed or recovered (SEIRIE) model, for which the state exposed (infected but not infectious), describing more realistically transmitted diseases such as tuberculosis. In future work, we also intend to investigate the effect of network topology on phase transitions when the SIRI model describes both transmitted diseases (σ 1 ).

  7. CMA Performance in CDMA Transmit Diversity System

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing-hua; FENG Guang-zeng

    2005-01-01

    Plenty of work have been done on Space-Time processing in which multiple transmit/receive antennas are used in conjunction with coding to exploit both spatial diversity and time diversity. Constant Mode Algorithm (CMA) is an efficient blind adaptive Multi-User Detection (MUD) algorithm for CDMA systems. In this paper, we put forward a novel receiver, which combines CMA blind adaptive Multi-user Detection with STBC technique, and compare the performances of the system using different CM algorithms including SDCMA (Steepest-Descent CMA), Standard Linearity Confine CMA(SLCCMA) and Least Squares CMA(LSCMA). Simulations have been done with multi-path Rayleigh channel.

  8. Hydrostatic limits of 11 pressure transmitting media

    Science.gov (United States)

    Klotz, S.; Chervin, J.-C.; Munsch, P.; LeMarchand, G.

    2009-04-01

    We present a systematic and comparative study of the pressure-induced solidification of 11 frequently used pressure transmitting fluids using the ruby fluorescence technique in a diamond anvil cell. These fluids are 1 : 1 and 5 : 1 iso-n pentane, 4 : 1 deuterated methanol-ethanol, 16 : 3 : 1 deuterated methanol-ethanol-water, 1 : 1 FC84-FC87 Fluorinert, Daphne 7474, silicone oil, as well as nitrogen, neon, argon and helium. The data provide practical guidelines for the use of these fluids in high pressure experiments up to 50 GPa.

  9. Reducing Transmitted Vibration Using Delayed Hysteretic Suspension

    Directory of Open Access Journals (Sweden)

    Lahcen Mokni

    2011-01-01

    Full Text Available Previous numerical and experimental works show that time delay technique is efficient to reduce transmissibility of vibration in a single pneumatic chamber by controlling the pressure in the chamber. The present work develops an analytical study to demonstrate the effectiveness of such a technique in reducing transmitted vibrations. A quarter-car model is considered and delayed hysteretic suspension is introduced in the system. Analytical predictions based on perturbation analysis show that a delayed hysteretic suspension enhances vibration isolation comparing to the case where the nonlinear damping is delay-independent.

  10. Discourse on the values transmitted in universities Uganda ...

    African Journals Online (AJOL)

    Discourse on the values transmitted in universities Uganda. ... suitability of the knowledge and values offered in African universities has been a matter ... It was found that material, social/ public, personal and religious values are transmitted to ...

  11. Common Culex Mosquitoes Don't Transmit Zika Virus

    Science.gov (United States)

    ... 161186.html Common Culex Mosquitoes Don't Transmit Zika Virus: Study These widespread insects do spread West Nile ... t appear to be able to transmit the Zika virus to people, researchers report. The researchers at Kansas ...

  12. Tracking target objects orbiting earth using satellite-based telescopes

    Energy Technology Data Exchange (ETDEWEB)

    De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J

    2014-10-14

    A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.

  13. Sexually transmitted diseases treatment guidelines, 2015.

    Science.gov (United States)

    Workowski, Kimberly A; Bolan, Gail A

    2015-06-05

    These guidelines for the treatment of persons who have or are at risk for sexually transmitted diseases (STDs) were updated by CDC after consultation with a group of professionals knowledgeable in the field of STDs who met in Atlanta on April 30-May 2, 2013. The information in this report updates the Sexually Transmitted Diseases Treatment Guidelines, 2010 (MMWR Recomm Rep 2010;59 [No. RR-12]). These updated guidelines discuss 1) alternative treatment regimens for Neisseria gonorrhoeae; 2) the use of nucleic acid amplification tests for the diagnosis of trichomoniasis; 3) alternative treatment options for genital warts; 4) the role of Mycoplasma genitalium in urethritis/cervicitis and treatment-related implications; 5) updated HPV vaccine recommendations and counseling messages; 6) the management of persons who are transgender; 7) annual testing for hepatitis C in persons with HIV infection; 8) updated recommendations for diagnostic evaluation of urethritis; and 9) retesting to detect repeat infection. Physicians and other health-care providers can use these guidelines to assist in the prevention and treatment of STDs.

  14. Sexually transmitted diseases treatment guidelines, 2010.

    Science.gov (United States)

    Workowski, Kimberly A; Berman, Stuart

    2010-12-17

    These guidelines for the treatment of persons who have or are at risk for sexually transmitted diseases (STDs) were updated by CDC after consultation with a group of professionals knowledgeable in the field of STDs who met in Atlanta on April 18-30, 2009. The information in this report updates the 2006 Guidelines for Treatment of Sexually Transmitted Diseases (MMWR 2006;55[No. RR-11]). Included in these updated guidelines is new information regarding 1) the expanded diagnostic evaluation for cervicitis and trichomoniasis; 2) new treatment recommendations for bacterial vaginosis and genital warts; 3) the clinical efficacy of azithromycin for chlamydial infections in pregnancy; 4) the role of Mycoplasma genitalium and trichomoniasis in urethritis/cervicitis and treatment-related implications; 5) lymphogranuloma venereum proctocolitis among men who have sex with men; 6) the criteria for spinal fluid examination to evaluate for neurosyphilis; 7) the emergence of azithromycin-resistant Treponema pallidum; 8) the increasing prevalence of antimicrobial-resistant Neisseria gonorrhoeae; 9) the sexual transmission of hepatitis C; 10) diagnostic evaluation after sexual assault; and 11) STD prevention approaches.

  15. The psychological aspects in sexually transmitted infections.

    Science.gov (United States)

    Campolmi, Eleonora; Santosuosso, Ugo; Silvestri, Caterina; Giomi, Barbara; Zuccati, Giuliano

    2016-04-01

    Over the last years the number of sexually transmitted diseases has greatly increased. This can be attributed mainly to less rigidity in the gender role and to the ever growing sexual liberalization. Sexuality today as in the past, represents an important and complex dimension of the human being. With respect to the psychological area many authors think that there are specific personality traits that to a higher extent compared to others might push individuals to carry out inconsiderate behavior among which there has been found a higher risk of sexually transmitted diseases (STD). In the present paper preliminary data of a research carried out provides information about sexual habits among patients of the IST of Florence. A sample of 344 individuals, from 15 to over 70-year-old, Italians and strangers, has been asked to fill up a self-administered questionnaire. Through these data the psychological aspects at the base of sexual habits in our reference sample are highlighted even more clearly. Through the analysis of these data it will be possible to get a larger number of information that can be used for the building of psychological support experiences that take into account the individual differences among patients one finds through consultations and support. The psychological support is very important for a lot of patients who belong to the center and show inappropriate sexual behavior and exposed to risky sexual behavior.

  16. [Risk of transfusional-transmitted infections].

    Science.gov (United States)

    Blejer, Jorgelina L; Carreras Vescio, Luis A; Salamone, Horacio J

    2002-01-01

    Although each donated unit of blood is tested for evidence of infection by specific agents, there are at least four potential reasons why transmission of these agents may still occur: a) the donor has negative laboratory test results during the early stages of infection, known as the window period, b) the existence of a chronic carrier state in which a clinically asymptomatic donor will persistently test negative on a screening assay, c) donors harbouring a mutant or atypical variant and d) laboratory errors when performing the screening tests. Measures to assure the safety of blood and blood components include use of voluntary donors, donor selection and questioning, laboratory testing for serological markers of infections, maintenance of registries of disqualified donors and, more recently, the introduction of direct testing for viral nucleic acids. All these measures must be accompanied by rigorous quality control systems. The potential risk of transfusion-transmitted infectious diseases can be estimated by reviewing the records of blood donations, the screening procedures and determining the prevalence of the serologic markers of infectious diseases. Accurate estimates of the risk of transfusion-transmitted infections are needed in order to monitor the safety of the blood supply and evaluate the yield and cost effectiveness of alternatives to allogeneic transfusion. Genomic screening for infectious agents, especially viruses, became possible with the development of various nucleic acid amplification techniques. They combine the advantages of direct detection of the organism with a sensitivity several orders of magnitude higher than that of traditional methods.

  17. Phase-only nulling for transmit antenna

    Science.gov (United States)

    Hussain, Moayyed A.; Yu, Kai-Bor

    1999-11-01

    This paper describes a technique for transmit antenna nulling for low-cost large sparse phased array radar system. Radar system described includes an array of elemental antennas, each with a transmit/receive (T/R) module. The T/R modules are operated at or near maximum output to achieve maximum CD-to-RF efficiency. A phase controller controls the phase shift, which are imparted by each module to its signal, to form a mainbeam and its associated sidelobes. A perturbation phase generator adds phase shifts computed, to form wide nulls in the sidelobe structure. The nulls are achieved at very minimal loss of gain, in the order of fraction of a dB. The speed of obtaining these nulls in real time allows a rapid steering of these nulls in a hostile environment. The thinned aperture allow designing a light weigh mobile system. In radar context, these nulls may be placed on a source of ground clutter, a set of jammers or a set of undesirable radio sources.

  18. Interference Alignment with Partially Coordinated Transmit Precoding

    CERN Document Server

    Yousafzai, Aimal Khan

    2011-01-01

    In this paper, we introduce an efficient interference alignment (IA) algorithm exploiting partially coordinated transmit precoding to improve the number of concurrent interference-free transmissions, i.e., the multiplexing gain, in multicell downlink. The proposed coordination model is such that each base-station simultaneously transmits to two users and each user is served by two base-stations. First, we show in a K-user system operating at the information theoretic upper bound of degrees of freedom (DOF), the generic IA is proper when $K \\leq 3$, whereas the proposed partially coordinated IA is proper when $K \\leq 5$. Then, we derive a non-iterative, i.e., one shot, IA algorithm for the proposed scheme when $K \\leq 5$. We show that for a given latency, the backhaul data rate requirement of the proposed method grows linearly with K. Monte-Carlo simulation results show that the proposed one-shot algorithm offers higher system throughput than the iterative IA at practical SNR levels.

  19. Multiple routes transmitted epidemics on multiplex networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dawei [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Shandong Provincial Key Laboratory of Computer Network, Shandong Computer Science Center, Jinan 250014 (China); Li, Lixiang [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Peng, Haipeng, E-mail: penghaipeng@bupt.edu.cn [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Luo, Qun; Yang, Yixian [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-02-01

    This letter investigates the multiple routes transmitted epidemic process on multiplex networks. We propose detailed theoretical analysis that allows us to accurately calculate the epidemic threshold and outbreak size. It is found that the epidemic can spread across the multiplex network even if all the network layers are well below their respective epidemic thresholds. Strong positive degree–degree correlation of nodes in multiplex network could lead to a much lower epidemic threshold and a relatively smaller outbreak size. However, the average similarity of neighbors from different layers of nodes has no obvious effect on the epidemic threshold and outbreak size. -- Highlights: •We studies multiple routes transmitted epidemic process on multiplex networks. •SIR model and bond percolation theory are used to analyze the epidemic processes. •We derive equations to accurately calculate the epidemic threshold and outbreak size. •ASN has no effect on the epidemic threshold and outbreak size. •Strong positive DDC leads to a lower epidemic threshold and a smaller outbreak size.

  20. Prevention of soil-transmitted helminth infection

    Directory of Open Access Journals (Sweden)

    Luciene Mascarini-Serra

    2011-01-01

    Full Text Available Soil-transmitted helminths (STHs form one of the most important groups of infectious agents and are the cause of serious global health problems. The most important STHs are roundworms (Ascaris lumbricoides, whipworms (Trichuris trichiura and hookworms (Necator americanus or Ancylostoma duodenale; on a global level, more than a billion people have been infected by at least one species of this group of pathogens. This review explores the general concepts of transmission dynamics and the environment and intensity of infection and morbidity of STHs. The global strategy for the control of soil-transmitted helminthiasis is based on (i regular anthelminthic treatment, (ii health education, (iii sanitation and personal hygiene and (iv other means of prevention with vaccines and remote sensoring. The reasons for the development of a control strategy based on population intervention rather than on individual treatment are discussed, as well as the costs of the prevention of STHs, although these cannot always be calculated because interventions in health education are difficult to measure. An efficient sanitation infrastructure can reduce the morbidity of STHs and eliminates the underlying cause of most poverty-related diseases and thus supports the economic development of a country.

  1. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  2. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  3. Adolescents' Sexually Transmitted Disease Protective Attitudes Predict Sexually Transmitted Disease Acquisition in Early Adulthood

    Science.gov (United States)

    Crosby, Richard A.; Danner, Fred

    2008-01-01

    Background: Estimates suggest that about 48% of nearly 19 million cases of sexually transmitted diseases (STDs) occurring annually in the United States are acquired by persons aged 15-24 years. The purpose of this study was to test the hypothesis that adolescents' attitudes about protecting themselves from STDs predict their laboratory-confirmed…

  4. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  5. Seamless Handovers in Cobra Teardrop Satellite Arrays

    Science.gov (United States)

    Draim, John E.; Cefola, Paul J.; Ernandes, Kenneth J.

    2007-06-01

    Satellite systems provide the most efficient and possibly the only means of achieving two-way global communications with mobile systems (ships, aircraft, and vehicular traffic). To date, such systems have used only circular orbits, either GEO or LEO. Medium altitude elliptical constellations, on the other hand, can provide an efficient and affordable alternative to these architectures. Users also benefit from their very high average and minimum elevation angles, resulting in minimum signal attenuation. Cobra Teardrop is unique in that it employs time synchronized 8-h left- and right-leaning elliptical orbits giving mid-latitude observers the illusion of viewing a single satellite continuously orbiting almost directly overhead! In reality, observers see six different satellites per day, for 4 h each (while in their active duty cycles). By design, Teardrop satellites are physically in very close proximity at the handover points. This favorable geometry can be utilized to achieve a seamless handover from one satellite to the other (not requiring any electronic buffering). Handover is accomplished at the precise instant that the total path lengths from the transmitting station through both satellites to the receiving station are exactly equal. In these improved Cobra Teardrop arrays, an order of magnitude increase in global communications capacity (equivalent GEO slots) can be realized over earlier Basic Cobra systems. For decades into the future, these new orbital systems could satisfy a widely expanding range of commercial, government, and military high data rate communication requirements. These would include, but not be limited to, satellite cellular, air traffic control, meteorological, and combat net radio systems. With these arrays, a much larger number of system operators could be supported, without mutual electronic interference, than would ever be possible with circular orbits.

  6. Optical antenna gain. I - Transmitting antennas

    Science.gov (United States)

    Klein, B. J.; Degnan, J. J.

    1974-01-01

    The gain of centrally obscured optical transmitting antennas is analyzed in detail. The calculations, resulting in near- and far-field antenna gain patterns, assume a circular antenna illuminated by a laser operating in the TEM-00 mode. A simple polynomial equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn that display the losses in antenna gain due to pointing errors and the cone angle of the beam in the far field as a function of antenna aperture size and its central obscuration. The results are presented in a series of graphs that allow the rapid and accurate evaluation of the antenna gain which may then be substituted into the conventional range equation.

  7. Optical antenna gain. 1: transmitting antennas.

    Science.gov (United States)

    Klein, B J; Degnan, J J

    1974-09-01

    The gain of centrally obscured optical transmitting antennas is analyzed in detail. The calculations, resulting in near- and far-field antenna gain patterns, assume a circular antenna illuminated by a laser operating in the TEM(00) mode. A simple polynomial equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn that display the losses in antenna gain due to pointing errors and the cone angle of the beam in the far field as a function of antenna aperture size and its central obscuration. The results are presented in a series of graphs that allow the rapid and accurate evaluation of the antenna gain which may then be substituted into the conventional range equation.

  8. Sexually Transmitted Disease and Male Infertility

    DEFF Research Database (Denmark)

    Fode, Mikkel; Fusco, Ferdinando; Lipshultz, Larry

    2016-01-01

    CONTEXT: Theoretically, sexually transmitted diseases (STDs) have the potential to disrupt male fertility; however, the topic remains controversial. OBJECTIVE: To describe the possible association between STDs and male infertility and to explore possible pathophysiologic mechanisms. EVIDENCE...... ACQUISITION: We performed a systematic literature review in accordance with the PRISMA guidelines. PubMed, Embase, and the Cochrane Library were searched for articles published before January 1, 2016, using the MeSH terms for a variety of STDs and infertility. The search was restricted to human studies...... performed in men and published in English. Studies were included if they contained original data on a possible association or a cause-and-effect relationship between STD and male infertility. Studies were considered only if they included an appropriate control group and/or comprehensive laboratory data. Due...

  9. Sexually Transmitted Diseases on Bipartite Graph

    Science.gov (United States)

    Wen, Luo-Sheng; Zhong, Jiang; Yang, Xiao-Fan

    2009-01-01

    We study the susceptible-infected-susceptible (SIS) epidemic model on bipartite graph. According to the difference of sex conception in western and oriental nations, we construct the Barabási Albert-Barabási Albert (BA-BA) model and Barabási-Albert Homogeneity (BA-HO) model for sexually transmitted diseases (STDs). Applying the rate equation approach, the positive equilibria of both models are given analytically. We find that the ratio between infected females and infected males is distinctly different in both models and the infected density in the BA-HO model is much less than that in the BA-BA model. These results explain that the countries with small ratio have less infected density than those with large ratio. Our numerical simulations verify these theoretical results.

  10. Sexually Transmitted Diseases on Bipartite Graph

    Institute of Scientific and Technical Information of China (English)

    WEN Luo-Sheng; ZHONG Jiang; YANG Xiao-Fan

    2009-01-01

    We study the susceptible-infected-susceptible (SIS) epidemic model on bipartite graph. According to the dif-ference of sex conception in western and oriental nations, we construct the Barabasi Albert-Barabasi Albert (BA-BA) model and Barabasi-Albert Homogeneity (BA-HO) model for sexually transmitted diseases (STDs). Applying the rate equation approach, the positive equilibria of both models are given analytically. We lind that the ratio between infected females and infected males is distinctly different in both models and the infected den-sity in the BA-HO model is much less than that in the BA-BA model. These results explain that the countries with small ratio have less infected density than those with large ratio. Our numerical simulations verify these theoretical results.

  11. Interviews with candidates for president transmitted

    Directory of Open Access Journals (Sweden)

    Wilson Gomes

    2012-07-01

    Full Text Available In election years, television interviews with presidential candidates, broadcast live, i.e. without the use of editing, have become an important genre of journalistic representation in Brazilian political campaigns. These interviews are conducted in network studios by well-known Brazilian news anchors. The fact that these interviews are transmitted directly to the electorate in an unedited form is generally offered as a guarantee of a genuine, authentic portrayal of the candidates themselves. The present work proposes that live network candidate interviews, rather than a means of political presentation on television, are actually an arena in which the institution of journalism attempts to use rhetorical and argumentative means to control the candidates’ discourse without relying on the traditional advantages conferred in daily news coverage.

  12. Guidelines to amateur divers working on archaeological sites reconnaisance and excavation in water

    Digital Repository Service at National Institute of Oceanography (India)

    Thakkar, M.

    stream_size 8 stream_content_type text/plain stream_name 2_Indian_Conf_Mar_Archaeol_I.O._Countries_1990_149.pdf.txt stream_source_info 2_Indian_Conf_Mar_Archaeol_I.O._Countries_1990_149.pdf.txt Content-Encoding ISO-8859-1 Content...

  13. Satellite-Delivered Learning.

    Science.gov (United States)

    Arnall, Gail C.

    1987-01-01

    Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

  14. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  15. China's Recoverable Satellites

    Institute of Scientific and Technical Information of China (English)

    Tang Boehang

    2008-01-01

    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  16. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  17. Energy-Efficient Optimal Power Allocation in Integrated Wireless Sensor and Cognitive Satellite Terrestrial Networks.

    Science.gov (United States)

    Shi, Shengchao; Li, Guangxia; An, Kang; Gao, Bin; Zheng, Gan

    2017-09-04

    This paper proposes novel satellite-based wireless sensor networks (WSNs), which integrate the WSN with the cognitive satellite terrestrial network. Having the ability to provide seamless network access and alleviate the spectrum scarcity, cognitive satellite terrestrial networks are considered as a promising candidate for future wireless networks with emerging requirements of ubiquitous broadband applications and increasing demand for spectral resources. With the emerging environmental and energy cost concerns in communication systems, explicit concerns on energy efficient resource allocation in satellite networks have also recently received considerable attention. In this regard, this paper proposes energy-efficient optimal power allocation schemes in the cognitive satellite terrestrial networks for non-real-time and real-time applications, respectively, which maximize the energy efficiency (EE) of the cognitive satellite user while guaranteeing the interference at the primary terrestrial user below an acceptable level. Specifically, average interference power (AIP) constraint is employed to protect the communication quality of the primary terrestrial user while average transmit power (ATP) or peak transmit power (PTP) constraint is adopted to regulate the transmit power of the satellite user. Since the energy-efficient power allocation optimization problem belongs to the nonlinear concave fractional programming problem, we solve it by combining Dinkelbach's method with Lagrange duality method. Simulation results demonstrate that the fading severity of the terrestrial interference link is favorable to the satellite user who can achieve EE gain under the ATP constraint comparing to the PTP constraint.

  18. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  19. DVB-S数字卫星传输%DVB-S Digital satellite Transmitting

    Institute of Scientific and Technical Information of China (English)

    张彤

    2005-01-01

    1995年DVB组织确立了数字卫星电视的标准DVB-S,1997年以DVB标准为基础的数字电视已经在全世界普及,服务上百万的观众。我国在1996年颁布广播电视数字传输技术体制,决定采用符合DVB-S标准的数字电视卫星广播系统。这为今后的数字高清晰度电视地面广播开辟了广阔的前景。

  20. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  1. Geodetic Secor Satellite

    Science.gov (United States)

    1974-06-01

    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  2. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  3. MULTIPLE TRELLIS CODED ORTHOGONAL TRANSMIT SCHEME FOR MULTIPLE ANTENNA SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, a novel multiple trellis coded orthogonal transmit scheme is proposed to exploit transmit diversity in fading channels. In this scheme, a unique vector from a set of orthogonal vectors is assigned to each transmit antenna. Each of the output symbols from the multiple trellis encoder is multiplied with one of these orthogonal vectors and transmitted from corresponding transmit antennas. By correlating with corresponding orthogonal vectors, the receiver separates symbols transmitted from different transmit antennas.This scheme can be adopted in coherent/differential systems with any number of transmit antennas. It is shown that the proposed scheme encompasses the conventional trellis coded unitary space-time modulation based on the optimal cyclic group codes as a special case. We also propose two better designs over the conventional trellis coded unitary space-time modulation. The first design uses 8 Phase Shift Keying (8-PSK) constellations instead of 16 Phase Shift Keying (16-PSK) constellations in the conventional trellis coded unitary space-time modulation. As a result, the product distance of this new design is much larger than that of the conventional trellis coded unitary space-time modulation. The second design introduces constellations with multiple levels of amplitudes into the design of the multiple trellis coded orthogonal transmit scheme. For both designs, simulations show that multiple trellis coded orthogonal transmit schemes can achieve better performance than the conventional trellis coded unitary space-time schemes.

  4. A Space Based Solar Power Satellite System

    Science.gov (United States)

    Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.

    2002-01-01

    (SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

  5. Transmit Power Optimisation in Wireless Network

    Directory of Open Access Journals (Sweden)

    Besnik Terziu

    2011-09-01

    Full Text Available Transmit power optimisation in wireless networks based on beamforming have emerged as a promising technique to enhance the spectrum efficiency of present and future wireless communication systems. The aim of this study is to minimise the access point power consumption in cellular networks while maintaining a targeted quality of service (QoS for the mobile terminals. In this study, the targeted quality of service is delivered to a mobile station by providing a desired level of Signal to Interference and Noise Ratio (SINR. Base-stations are coordinated across multiple cells in a multi-antenna beamforming system. This study focuses on a multi-cell multi-antenna downlink scenario where each mobile user is equipped with a single antenna, but where multiple mobile users may be active simultaneously in each cell and are separated via spatial multiplexing using beamforming. The design criteria is to minimize the total weighted transmitted power across the base-stations subject to SINR constraints at the mobile users. The main contribution of this study is to define an iterative algorithm that is capable of finding the joint optimal beamformers for all basestations, based on a correlation-based channel model, the full-correlation model. Among all correlated channel models, the correlated channel model used in this study is the most accurate, giving the best performance in terms of power consumption. The environment here in this study is chosen to be Non-Light of- Sight (NLOS condition, where a signal from a wireless transmitter passes several obstructions before arriving at a wireless receiver. Moreover there are many scatterers local to the mobile, and multiple reflections can occur among them before energy arrives at the mobile. The proposed algorithm is based on uplink-downlink duality using the Lagrangian duality theory. Time-Division Duplex (TDD is chosen as the platform for this study since it has been adopted to the latest technologies in Fourth

  6. HJ-1A And HJ-1B Small Satellite Constellation For Environment And Disaster Monitoring

    Institute of Scientific and Technical Information of China (English)

    Bai Zhaoguang

    2009-01-01

    @@ HJ-1A and HJ-1B small satellites were launched atop a LM-2C/SMA on September 6, 2008 from Taiyuan Satellite Launch Center. The satellites began to transmit back images from September 8 and the constellation formed on October 13. After 5 months of orbit testing and operationevaluation, China's first optical satelliteconstellation passed its performancereview and was delivered to the Ministryof Civil Affairs and the Ministry ofEnvironmental Protection by ChinaAerospace Science and Technology Corporation and China Satellite Launch6 Tracking Control General.

  7. Telemetry beacon for Polish payload on BRITE-PL-2 satellite

    Science.gov (United States)

    Woźniak, Grzegorz; Stolarski, Marcin

    2013-10-01

    Small satellite missions are becoming more popular. To reduce costs of such projects COTS are used to build the spacecraft and amateur bands are utilized to communicate with it. Although using the hamradio frequencies is free of charge and requires only coordination procedures [1], it is good habit to include on satellite some service for radioamateur society in return. The BRITE-PL-2 Heweliusz [2] satellite - the second Polish satellite from BRITE constellation - will have an S-Band beacon transmitting Morse code signals.

  8. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  9. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  10. Sexually transmitted diseases in children in India

    Directory of Open Access Journals (Sweden)

    Dhawan Jyoti

    2010-01-01

    Full Text Available Sexually transmitted diseases (STDs in children are not uncommon in India, though systematic epidemiological studies to determine the exact prevalence are not available. STDs in children can be acquired via sexual route or, uncommonly, via non-sexual route such as accidental inoculation by a diseased individual. Neonatal infections are almost always acquired intrauterine or during delivery. Voluntary indulgence in sexual activity is also an important factor in acquisition of STDs in childhood. Sexual abuse and sex trafficking remain the important problems in India. Surveys indicate that nearly half of the children are sexually abused. Most at risk children are street-based, homeless or those living in or near brothels. Last two decades have shown an increase in the prevalence of STDs in children, though most of the data is from northern part of the country and from major hospitals. However, due to better availability of antenatal care to majority of women, cases of congenital syphilis have declined consistently over the past two-three decades. Other bacterial STDs are also on decline. On the other hand, viral STDs such as genital herpes and anogenital warts are increasing. This reflects trends of STDs in the adult population. Concomitant HIV infection is uncommon in children. Comprehensive sex education, stringent laws to prevent sex trafficking and child sexual abuse, and antenatal screening of all the women can reduce the prevalence of STDs in children.

  11. Molecular Diagnostics for Soil-Transmitted Helminths

    Science.gov (United States)

    O'Connell, Elise M.; Nutman, Thomas B.

    2016-01-01

    Historically, the diagnosis of soil-transmitted helminths (STHs) (e.g., Strongyloides stercoralis, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, and Ascaris lumbricoides) has relied on often-insensitive microscopy techniques. Over the past several years, there has been an effort to use molecular diagnostics, particularly quantitative polymerase chain reaction (qPCR), to detect intestinal pathogens. While some platforms have been approved by regulatory bodies (e.g., Food and Drug Administration) to detect intestinal bacteria, viruses, and protozoa, there are no approved tests currently available for STH. Although studies comparing qPCR to microscopy methods for STH are imperfect, due in large part to a lack of a sufficient gold standard, they do show a significant increase in sensitivity and specificity of qPCR compared with microscopic techniques. These studies, as well as the advantages and disadvantages of using qPCR for STH diagnosis, are discussed. Guidelines for those designing future studies utilizing qPCR are proposed for optimizing results, as is the proposition for using standardized molecular diagnostics routinely for STH in clinical laboratories and for field-based studies when possible. PMID:27481053

  12. Sexually transmitted infections and older adults.

    Science.gov (United States)

    Johnson, Beverly K

    2013-11-01

    Older adults continue to be sexually active in their later years. A range of sexually transmitted infections (STIs) such as chlamydia, gonorrhea, syphilis, and HIV have been reported among older adults. Risk factors for STIs in older populations include (a) normal sexual changes associated with aging (e.g., increased time to attain an erection, decreased vaginal lubrication, decreases in sexual hormones); (b) psychosocial changes (e.g., loss of partner or spouse and re-entering the dating scene); and (c) risky sexual behaviors, including no or infrequent use of condoms. Screening of adults for STIs should occur regardless of age based on guidelines such as those from the Centers for Disease Control and Prevention and the U.S. Preventive Services Task Force. As discussed in this article, nurses can use assessment guides and engage in interventions such as counseling and education with older adults to reduce STI risk or refer for treatment. Numerous online resources exist for both nurses and older adults to increase knowledge of STIs.

  13. Depression Among Sexually Transmitted Disease Patients

    Institute of Scientific and Technical Information of China (English)

    黄长征; 李碧芳; 涂亚庭; 刘志香; 林能兴

    2001-01-01

    Objective: To investigate the depression status of patients with sexually transmitted diseases (STDs).Methods: The depression status of fifty-one hospitalized STD patients was evaluated in a randomized control study using Zung's Quantitative Table. 18 healthy control patients with similar demographic backgrounds were randomly chosen as controls. Patients with scores above or equal to 40 were considered to be suffering from depression.Results: The prevalence rate of depression in the patient group was obviously higher than that of in the control (X2=16.456,P<0.01). Prevalence of depression was found to be significantly related to occupation (P<0.05). Though the prevalence was not found to differ significantly between those with a treatment course less than 2 months and those with one longer or equal to 2 months (X2=0.041, P>0.05), the mean depression scores of the former group were significantly higher than those of the latter (P<0.01). No significant differences were found between new versus relapsing disease, married versus non-married, male versus female, or differing educational backgrounds.Conclusion: STD patients showed significant prevalence of depression.

  14. Modular approach for satellite communication ground terminals

    Science.gov (United States)

    Gould, G. R.

    1984-01-01

    The trend in satellite communications is toward completely digital, time division multiple access (TDMA) systems with uplink and downlink data rates dictated by the type of service offered. Trunking terminals will operate in the 550 MBPS (megabit per second) region uplink and downlink, whereas customer premise service (CPS) terminals will operate in the 25 to 10 MBPS region uplink and in the 200 MBPS region downlink. Additional criteria for the ground terminals will be to maintain clock sychronization with the system and burst time integrity to within a matter of nanoseconds, to process required order-fire information, to provide adaptive data scrambing, and to compensate for variations in the user input output data rates, and for changes in range in the satellite communications links resulting from satellite perturbations in orbit. To achieve the required adaptability of a ground terminal to the above mentioned variables, programmable building blocks can be developed that will meet all of these requirements. To maintain system synchronization, i.e., all bursted data arriving at the satellite within assigned TDMA windows, ground terminal transmit data rates and burst timing must be maintained within tight tolerances. With a programmable synchronizer as the heart of the terminal timing generation, variable data rates and burst timing tolerances are achievable. In essence, the unit inputs microprocessor generated timing words and outputs discrete timing pulses.

  15. LTE Adaptation for Mobile Broadband Satellite Networks

    Directory of Open Access Journals (Sweden)

    Bastia Francesco

    2009-01-01

    Full Text Available One of the key factors for the successful deployment of mobile satellite systems in 4G networks is the maximization of the technology commonalities with the terrestrial systems. An effective way of achieving this objective consists in considering the terrestrial radio interface as the baseline for the satellite radio interface. Since the 3GPP Long Term Evolution (LTE standard will be one of the main players in the 4G scenario, along with other emerging technologies, such as mobile WiMAX; this paper analyzes the possible applicability of the 3GPP LTE interface to satellite transmission, presenting several enabling techniques for this adaptation. In particular, we propose the introduction of an inter-TTI interleaving technique that exploits the existing H-ARQ facilities provided by the LTE physical layer, the use of PAPR reduction techniques to increase the resilience of the OFDM waveform to non linear distortion, and the design of the sequences for Random Access, taking into account the requirements deriving from the large round trip times. The outcomes of this analysis show that, with the required proposed enablers, it is possible to reuse the existing terrestrial air interface to transmit over the satellite link.

  16. A variable bandwidth assignment scheme for the Land Mobile Satellite experiment

    Science.gov (United States)

    Yan, T.-Y.; Li, V. O. K.

    The Mobile Satellite Experiment is a proposed experimental satellite-based communications network which provides data and voice communications to mobile terminals dispersed in geographically dispersed areas. In this paper, an analytical model is developed to calculate the performance of a Variable Bandwidth Assignment (VBA) Scheme. Under this scheme, the satellite channel bandwidth is dynamically reassigned so that a message may be transmitted in the shortest possible time. To transmit a long message, message channels will be reconfigured to have more bandwidth such that the transmission time is reduced, while to transmit a short message, the channel bandwidth will be shrunk such that the released bandwidth can be used to serve other messages. The model is illustrated with numerical examples. It is shown that a VBA scheme can achieve considerable improvement in transmission delays over a Fixed Bandwidth Assignment Scheme.

  17. Dependent surveillance through an experimental satellite data link system

    Science.gov (United States)

    Cobley, G. A.

    The development and testing of an experimental dependent aircraft-surveillance system using a satellite data link is reported. In this system, the aircraft position is determined onboard using GPS or inertial navigation, enclosed in a message block using a data-link system, and transmitted to an Inmarsat GEO communication satellites; the ground station receives and analyzes the data to keep constant track of the aircraft position. The hardware implementation and the results of demonstrations performed on flights from Iowa to Wisconsin and the North Atlantic are discussed, and diagrams and maps are provided.

  18. Sexually transmitted diseases and sexual function.

    Science.gov (United States)

    Sadeghi-Nejad, Hossein; Wasserman, Marlene; Weidner, Wolfgang; Richardson, Daniel; Goldmeier, David

    2010-01-01

    There is a need for state-of-the-art information in the area of sexually transmitted infections (STIs) in relation to sexual function. There are an estimated 60 million people living with and 340 million with treatable STIs. Surveys show sexual problems to be as high as 35% for men and 55% for women; however, there is little research directly assessing relationships between infection and sexual function. To show that STIs are associated with (and may cause) sexual dysfunction. Conversely, sexual dysfunction can increase patients' risk of STI acquisition. In men, erectile dysfunction (ED) associated with condom use may lead to unsafe sexual practices and, hence, STI acquisition. The role of various therapies including phosphodiesterase type 5 inhibitors in the treatment of ED in positive men taking social drugs will be explored. To provide state-of-the-art knowledge concerning sexual function and STIs, representing the opinions of five experts from four countries developed in a consensus process and encompassing a detailed literature review over a 2-year period. Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. This article highlights major factors causing the spread of STIs and suggests management interventions to prevent further spread of HIV/STIs, focusing on the juxtaposition between STIs and sexual functioning. Women's unique vulnerabilities to HIV/STIs (biological and physiological issues, gender-based violence, gender inequity) and their impact on women's sexual function are reviewed. Similarly, men's unique vulnerabilities to HIV/STIs including condom use, disclosure, voluntary counseling and testing, multiple concurrent sexual partners, and recreational drug use--particularly in homosexual men--are explored, as is the association of prostatitis and sexual function. Lastly, the article reviews the relationship between circumcision and sexual dysfunction. A

  19. Global epidemiology of sexually transmitted diseases

    Institute of Scientific and Technical Information of China (English)

    Carlos T. Da Ros; Caio da Silva Schmitt

    2008-01-01

    Sexually transmitted diseases (STDs) are among the first ten causes of unpleasant diseases in young adult males in developing countries and the second major cause of unpleasant diseases in young adult women. Adolescents and new acquired STDs. In general, STDs are epidemics and present an enormous health and economic consequences.An adequate screening for STDs should be done on a routine basis in every part of the world. Many STDs are asymptomatic and therefore can difficult to control. The purpose of reporting of STDs is to ensure that persons who are infected will be quickly diagnosed and appropriately treated to control the spread of infection and also so that partners are notified, tested and appropriately treated. It is estimated that reported cases of STDs represent only High-risk sexual behavior is a highly contributive factor of this process as it often leads to teenage pregnancies and HIV/AIDS. One possible explanation for this behavior is that people do not have enough information about the transmission of STDs or ignore the precautions required for safe sex. Approximately 60% of new HIV infections worldwide occur in young people. The frequency of high-risk behaviors among youths may also be influenced by opportunity to engage in them, particularly the amount of time that they are unsupervised by adults. However, in diagnosing and treating these patients, we can effectively prevent the spread of HIV/AIDS. Individuals infected with STDs are of the genital tract lining or skin creates a portal of entry for HIV and, hence, HIV-infected individuals with other STDs are more likely to shed HIV in their genital secretions. To date, the condom is the most effective method available for males for protection against STDs. It is important to control STDs, and prevention can be the key of this process. Prevention can be achieved through education of the population, identification of symptomatic and asymptomatic people, and effective diagnosis and treatment of these

  20. Functions of retired GEO communication satellites in improving the PDOP value of CAPS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper briefly introduces the maneuverable feature of the slightly inclined geosynchronous orbit (SIGSO) satellites under a new control model degraded from the geosynchronous orbit (GEO) communication satellites which will retire as most of the fuel in these satellites has been consumed. Basing on the transmitting Chinese Area Positioning System (CAPS), the authors, by analyses, indicate that such satellites can make an improvement to CAPS constellation configuration, especially to the PDOP value from simulation. The results show that the use of SIGSO satellites can (1) actualize three-dimensional (3D) navigation and positioning compared with the situation, which, only using GEO satellites, cannot be carried out, and improve navigation and positioning accuracy to some extent; (2) reuse the communication services of these satellites for more years, and GEO communication satellites will be retired at a later time and delay their time to become space debris and reduce their pollution of the space environment, so that valuable space resources are maximally used. As for the use of these satellites in the transmitting positioning system, the authors present some views and suggestions in this work.

  1. Functions of retired GEO communication satellites in improving the PDOP value of CAPS

    Institute of Scientific and Technical Information of China (English)

    HAN YanBen; MA LiHua; QIAO QiYuan; YIN ZhiQiang; SHI HuLi; AI GuoXiang

    2009-01-01

    This paper briefly Introduces the maneuverable feature of the slightly Inclined geosynchronous orbit (SlGSO) satellites under e new control model degraded from the geosynchronous orbit (GEO) communication satellites which will retire as most of the fuel in these satellites has been consumed.Basing on the transmitting Chinese Area Positioning System (CAPS),the authors,by analyses,indicate that such satellites can make an improvement to CAPS constellation configuration,especially to the PDOP value from simulation.The results show that the use of SIGSO satellites can (1) actualize three-dimensional (3D) navigation and positioning compared with the situation,which,only using GEO satellites,cannot be carried out,and improve navigation and positioning accuracy to some extent; (2) reuse the communication services of these satellites for more years,and GEO communication satellites will be retired at a later time and delay their time to become space debris and reduce their pollution of the apace environment,so that valuable space resources are maximally used.As for the use of these satellites in the transmitting positioning system,the authors present some views and suggestions in this work.

  2. An adaptive linearizer for 16-QAM transmission over non-linear satellite channels

    Science.gov (United States)

    Shanmugan, K. Sam; Ruggles, M. J.

    An adaptive nonlinear equalization scheme that consists of a predistorter located at the transmitting earth station and a linear equalizer at the receiving earth station is described. Algorithms for automatically adjusting the predistorter and the linear equalizer are presented. The effectiveness of the scheme is evaluated using simulations. It is shown that the scheme improves the performance of a 16-queued access memory system operating over a typical satellite channel by minimizing degradations in the signal as it is transmitted over a band-limited satellite channel.

  3. Integrated Reconfigurable High-Voltage Transmitting Circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger

    2014-01-01

    -out and measurements are performed on the integrated circuit. The transmitting circuit is reconfigurable externally making it able to drive a wide variety of CMUTs. The transmitting circuit can generate several pulse shapes, pulse voltages up to 100 V, maximum pulse range of 50 V and frequencies up to 5 MHz. The area...

  4. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  5. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  6. Methods of satellite oceanography

    Science.gov (United States)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  7. Communication Systems through Artificial Earth Satellites (Selected Pages)

    Science.gov (United States)

    1987-02-05

    POX Fs (8.2.11) is 0(F) dF If on input of weighing circuit fluctuation noise with uniform spectrum acts, spectral power density in numerator and...Possibly also realization MV with asynchronous operation of terrestrial stations, that we will designate through MVA . In the case MVA each terrestrial...according to the frequcrncy. With MVA through receiving-transmitting equipment of satellite into some tiMe intervals simultaneous possible passage of signals

  8. Transfusion-transmitted infections: Existing and emerging pathogens

    Directory of Open Access Journals (Sweden)

    Kaur Paramjit

    2005-01-01

    Full Text Available In general, the risk of transfusion-transmitted infections has been greatly reduced today. However, blood-borne bacterial and parasitic infections and emerging infections transmitted through transfusion are an area of increasing concern. Implementation of stringent donor eligibility criteria, improved donor screening and more sophisticated as well as sensitive methods of antibody, antigen and viral genome detection, have virtually eliminated transfusion transmitted infection in developed countries. In developing countries like India, the risk of transfusion-transmitted infections is still considerable. A comprehensive MEDLINE search and review of relevant transfusion medicine literature were carried out and the data extracted and studied with particular reference to emerging pathogens transmitted through blood transfusion and posing a huge threat.

  9. [Sexually transmitted diseases (STD) and contraception].

    Science.gov (United States)

    Erny, R; Porte, H

    1989-06-01

    Sexually transmitted diseases (STDs) have shown a considerable resurgence in recent years both in number of cases and in spread of new infectious agents. The spread of STDs is favored by numerous factors including the liberalization of sexual behavior made possible by reliable contraception. Information on STDs has not been widely diffused. Changes in the status of women and the development of means of communication and transportation have encouraged less rigid control of sexual behavior. STDs themselves have often escaped diagnosis or not been cured despite treatment, increasing the risk of spread. Numerous organisms cause STDs, from external parasites to life-threatening viruses. 60% of upper genital tract infections that can lead to sterility, tubal alterations, ectopic pregnancy and pain result from STDs. Chlamydia infections are insidious and chronic, and cause greater damage with each recurrence. The risk of STDs should be considered in contraceptive choice along with other indications and contraindications. Combined oral contraceptives provide protection against acute upper genital tract infections. The protective role has been explained by scanty and highly viscous cervical mucus forming a barrier against germs and by reductions of menstrual flow, myometrial activity, and inflammation. It is actually uncertain whether combined oral contraceptives protect against latent chlamydia infections, since higher rates of cervicitis caused by chlamydia have been found in pill users. In situations carrying risk of STDs, pill users should be protected by a supplementary barrier method. IUDs have been implicated in numerous studies in acute pelvic infections. Possible explanations are the local trauma and inflammations due to the physical presence of the IUD, more abundant bleeding, absence of a cervical barrier to motile sperm that could be a vector for germs, and possible ascent of the infectious agent on the string. Other risk factors are involved. Epidemiologic

  10. A preliminary design for a satellite power system

    Science.gov (United States)

    Enriquez, Clara V.; Kokaly, Ray; Nandi, Saumya; Timmons, Mike; Garrard, Mark; Mercado, Rommel; Rogers, Brian; Ugaz, Victor

    1991-01-01

    Outlined here is a preliminary design for a Solar Power Satellite (SPS) system. The SPS will provide a clean, reliable source of energy for mass consumption. The system will use satellites in geostationary orbits around the Earth to capture the sun's energy. The intercepted sunlight will be converted to laser beam energy which can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting to one ground station. The SPs technology uses multi-layer solar cell technology arranged on a 20 sq km planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Construction will take place in low Earth orbit and array sections, 20 in total, will be sailed on the solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing panels (SSAPs). The primary truss elements used to support the arrays are composed on composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

  11. Cable Modems' Transmitted RF: A Study of SNR, Error Rates, Transmit Levels, and Trouble Call Metrics

    Science.gov (United States)

    Tebbetts, Jo A.

    2013-01-01

    Hypotheses were developed and tested to measure the cable modems operational metrics response to a reconfiguration of the cable modems' transmitted RF applied to the CMTS. The purpose of this experiment was to compare two groups on the use of non-federal RF spectrum to determine if configuring the cable modems' transmitted RF from 25.2…

  12. Preliminary environmental assessment for the satellite power system (SPS). Revision 1. Volume 1. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    A preliminary assessment of the environmental impacts of the proposed satellite power system (SPS) is summarized here. In this system, satellites would collect solar energy in space, convert it to microwaves, and transmit the microwaves to receiving antennas (rectennas) on earth. At the rectennas, the microwaves would be converted to electricity. The assessment considers microwave and nonmicrowave effects on the terrestrial environment and human health, atmospheric effects, and disruption of communications and other electromagnetic systems.

  13. Satellites of spiral galaxies

    Science.gov (United States)

    Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

    1993-01-01

    We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

  14. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  15. Sexually transmitted diseases among psychiatric patients in Brazil.

    Science.gov (United States)

    Dutra, Maria Rita Teixeira; Campos, Lorenza Nogueira; Guimarães, Mark Drew Crosland

    2014-01-01

    Sexually transmitted diseases are still highly prevalent worldwide and represent an important public health problem. Psychiatric patients are at increased risk of sexually transmitted diseases but there are scarce published studies with representative data of this population. We sought to estimate the prevalence and correlates of self-reported sexually transmitted diseases among patients with mental illnesses under care in a national representative sample in Brazil (n=2145). More than one quarter of the sample (25.8%) reported a lifetime history of sexually transmitted disease. Multivariate analyses showed that patients with a lifetime sexually transmitted disease history were older, had history of homelessness, used more alcohol and illicit drugs, suffered violence, perceived themselves to be at greater risk for HIV and had high risk sexual behavioral: practised unprotected sex, started sexual life earlier, had more than ten sexual partners, exchanged money and/or drugs for sex and had a partner that refused to use condom. Our findings indicate a high prevalence of self-reported sexually transmitted diseases among psychiatric patients in Brazil, and emphasize the need for implementing sexually transmitted diseases prevention programs in psychiatric settings, including screening, treatment, and behavioral modification interventions.

  16. Sexually transmitted diseases among psychiatric patients in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Rita Teixeira Dutra

    2014-01-01

    Full Text Available Sexually transmitted diseases are still highly prevalent worldwide and represent an important public health problem. Psychiatric patients are at increased risk of sexually transmitted diseases but there are scarce published studies with representative data of this population. We sought to estimate the prevalence and correlates of self-reported sexually transmitted diseases among patients with mental illnesses under care in a national representative sample in Brazil (n = 2145. More than one quarter of the sample (25.8% reported a lifetime history of sexually transmitted disease. Multivariate analyses showed that patients with a lifetime sexually transmitted disease history were older, had history of homelessness, used more alcohol and illicit drugs, suffered violence, perceived themselves to be at greater risk for HIV and had high risk sexual behavioral: practised unprotected sex, started sexual life earlier, had more than ten sexual partners, exchanged money and/or drugs for sex and had a partner that refused to use condom. Our findings indicate a high prevalence of self-reported sexually transmitted diseases among psychiatric patients in Brazil, and emphasize the need for implementing sexually transmitted diseases prevention programs in psychiatric settings, including screening, treatment, and behavioral modification interventions.

  17. Integrated reconfigurable high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger

    2015-01-01

    In this paper a high-voltage transmitting circuit aimed for capacitive micromachined ultrasonic transducers (CMUTs) used in scanners for medical applications is designed and implemented in a 0.35 μm high-voltage CMOS process. The transmitting circuit is reconfigurable externally making it able...... performance. The design occupies an on-chip area of 0.938 mm2 and the power consumption of a 128-element transmitting circuit array that would be used in an portable ultrasound scanner is found to be a maximum of 181 mW....

  18. Integrated reconfigurable high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger;

    2015-01-01

    In this paper a high-voltage transmitting circuit aimed for capacitive micromachined ultrasonic transducers (CMUTs) used in scanners for medical applications is designed and implemented in a 0.35 μm high-voltage CMOS process. The transmitting circuit is reconfigurable externally making it able...... performance. The design occupies an on-chip area of 0.938 mm2 and the power consumption of a 128-element transmitting circuit array that would be used in an portable ultrasound scanner is found to be a maximum of 181 mW....

  19. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  20. Measures of Disassortativeness and their Application to Directly Transmitted Infections

    NARCIS (Netherlands)

    Farrington, C. P.; Whitaker, H. J.; Wallinga, J.; Manfredi, P.

    2009-01-01

    We propose a measure of disassortativeness to summarize contact patterns relevant to the transmission of directly transmitted infections. We discuss the properties of this measure, describe standardization relative to homogeneous mixing, and generalize it to multivariate contact structures. We explo

  1. Soil transmitted helminth infection among farmers in Ukwa West ...

    African Journals Online (AJOL)

    Soil transmitted helminth infection among farmers in Ukwa West Local Government Area, Abia State, south-east, Nigeria. ... Open Access DOWNLOAD FULL TEXT ... Collected data were analysed using descriptive and analytical tools. Results: ...

  2. Transmit TACAN Bearing Information with a Circular Array

    Directory of Open Access Journals (Sweden)

    W. Mark Dorsey

    2015-01-01

    Full Text Available Using TACAN and array fundamentals, we derive an architecture for transmitting TACAN bearing information from a circular array with time-varying weights. We evaluate performance for a simulated example array of Vivaldi elements.

  3. Transmittance spectroscopy and transmitted multispectral imaging to map covered paints

    Directory of Open Access Journals (Sweden)

    Antonino Cosentino

    2016-01-01

    Full Text Available Transmitted spectroscopy and transmitted multispectral imaging in the 400-900 nm range have been applied for the mapping and tentative identification of paints covered by a white preparation as in the case of a ground laid for reusing a canvas for another painting. These methods can be applied to polychrome works of art, as long as their support and new preparation are sufficiently translucent. This work presents the transmittance spectra acquired from a test board consisting of a prepared canvas with swatches of 54 pigments covered with titanium white and the multispectral images realized with transmitted light to map covered paints on a mock-up painting. It was observed that 18 out of 54 historical pigments provide characteristic transmittance spectra even underneath a titanium white preparation layer and that transmitted light multispectral imaging can map hidden paint layers.

  4. Draft genome sequence of the sexually transmitted pathogen Trichomonas vaginalis

    DEFF Research Database (Denmark)

    Carlton, Jane M.; Hirt, Robert P.; Silva, Joana C.

    2007-01-01

    We describe the genome sequence of the protist Trichomonas vaginalis, a sexually transmitted human pathogen. Repeats and transposable elements comprise about two-thirds of the approximately 160-megabase genome, reflecting a recent massive expansion of genetic material. This expansion...

  5. Measures of Disassortativeness and their Application to Directly Transmitted Infections

    NARCIS (Netherlands)

    Farrington, C. P.; Whitaker, H. J.; Wallinga, J.; Manfredi, P.

    2009-01-01

    We propose a measure of disassortativeness to summarize contact patterns relevant to the transmission of directly transmitted infections. We discuss the properties of this measure, describe standardization relative to homogeneous mixing, and generalize it to multivariate contact structures. We explo

  6. How is Macro News Transmitted to Exchange Rates? (December 2003)

    OpenAIRE

    Martin D.D. Evans

    2005-01-01

    This paper tests whether macroeconomic news is transmitted to exchange rates via the transactions process and if so, what share occurs via transactions versus the traditional direct channel. We identify the link between order flow and macro news using a heteroskedasticity-based approach, a la Rigobon and Sack (2002). In both daily and intra-daily data, order flow varies considerably with macro news flow. At least half of the effect of macro news on exchange rates is transmitted via order flow.

  7. How is Macro News Transmitted to Exchange Rates?

    OpenAIRE

    Martin D.D. Evans; Lyons, Richard K.

    2003-01-01

    This paper tests whether macroeconomic news is transmitted to exchange rates via the transactions process and if so, what share occurs via transactions versus the traditional direct channel. We identify the link between order flow and macro news using a heteroskedasticity-based approach, a la Rigobon and Sack (2002). In both daily and intra-daily data, order flow varies considerably with macro news flow. At least half of the effect of macro news on exchange rates is transmitted via order flow.

  8. Risks of occupational expsoures to hand-transmitted vibration: VIBRISKS

    OpenAIRE

    Griffin, Michael J.; Lewis, Christopher H.; Bovenzi, Massimo; Lemerle, Pierre; Lundström, Ronnie

    2004-01-01

    VIBRISKS seeks to improve understanding of the risk of injury from hand-transmitted vibration and whole-body vibration by means of epidemiological studies supported by fundamental laboratory research. VIBRISKS is a consortium of six partners from six European countries (France, Germany, Italy, Sweden, The Netherlands, UK). The four-year research project, which commenced in 2003, involves three work packages devoted to hand-transmitted vibration and three work packages devoted to whole-body vi...

  9. Serological Strains of Tobacco Ringspot Virus Transmitted by Xiphinema americanum.

    Science.gov (United States)

    Rush, M C

    1970-07-01

    Five serological strains of tobacco ringspot virus isolated from naturally infected tobacco in North Carolina, and a strain isolated from watermelon in the Rio Grande Valley of Texas were transmitted from cucumber to cucumber by mass-screened and handpicked Xiphinerna americanum from North Carolina. The Eucharis mottle strain from Peru was not transmitted, indicating that a specific strain-vector relationship may exist between the geographically isolated strains from North and South America.

  10. Some Models for Epidemics of Vector-Transmitted Diseases

    OpenAIRE

    Brauer, Fred; Castillo-Chavez, Carlos; Mubayi, Anuj; Towers, Sherry

    2016-01-01

    Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito) vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birt...

  11. The adaptive optics and transmit system for NASA's Laser Communications Relay Demonstration project

    Science.gov (United States)

    Roberts, Lewis C.; Burruss, Rick; Fregoso, Santos; Herzog, Harrison; Piazzola, Sabino; Roberts, Jennifer E.; Spiers, Gary D.; Truong, Tuan N.

    2016-09-01

    The Laser Communication Relay Demonstration is NASA's multi-year demonstration of laser communication to a geosynchronous satellite. We are currently assembling the optical system for the first of the two baseline ground stations. The optical system consists of an adaptive optics system, the transmit system and a camera for target acquisition. The adaptive optics system is responsible for compensating the downlink beam for atmospheric turbulence and coupling it into the modem's single mode fiber. The adaptive optics system is a woofer/tweeter design, with one deformable mirror correcting for low spatial frequencies with large amplitude and a second deformable mirror correcting for high spatial frequencies with small amplitude. The system uses a Shack- Hartmann wavefront sensor. The transmit system relays four beacon beams and one communication laser to the telescope for propagation to the space terminal. Both the uplink and downlink beams are centered at 1.55 microns. We present an overview of the design of the system as well as performance predictions including time series of coupling efficiency and expected uplink beam quality.

  12. A Flexible Phased-MIMO Array Antenna with Transmit Beamforming

    Directory of Open Access Journals (Sweden)

    Wen-Qin Wang

    2012-01-01

    Full Text Available Although phased-array antennas have been widely employed in modern radars, the requirements of many emerging applications call for new more advanced array antennas. This paper proposes a flexible phased-array multiple-input multiple-output (MIMO array antenna with transmit beamforming. This approach divides the transmit antenna array into multiple subarrays that are allowed to overlap each subarray coherently transmits a distinct waveform, which is orthogonal to the waveforms transmitted by other subarrays, at a distinct transmit frequency. That is, a small frequency increment is employed in each subarray. Each subarray forms a directional beam and all beams may be steered to different directions. The subarrays jointly offer flexible operating modes such as MIMO array which offers spatial diversity gain, phased-array which offers coherent directional gain and frequency diverse array which provides range-dependent beampattern. The system performance is examined by analyzing the transmit-receive beampatterns. The proposed approach is validated by extensive numerical simulation results.

  13. Mobile satellite news gathering (SNG) system; Soko SNG (Satellite News Gathering) shasaikyoku

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Commercialization was made for broadcasting stations on a mobile station system capable of capturing a satellite automatically while the system is moving. Its feature is the enhanced tracking accuracy as a result of using the Company's original null-sensor (see Note), and detecting and controlling intersecting polarized waves of reference signals from the satellite. The material for transmission is digitally transmitted by MPEG2, making it possible to transmit more data than by conventional systems. The system is being used for live broadcasting of marathon races and emergency news broadcasting. It is expected that the system may be applied to applications other than broadcasting stations, such as automobiles and ships. (Note: A null-sensor is a unit used for adjusting antenna directions for an SNG transmitter. It uses IF receiving signals of H/V polarized waves of parabolic antenna as an input, and outputs the main polarized wave level and the intersecting polarized wave level.) (translated by NEDO)

  14. System for electronic transformation and geographic correlation of satellite television information. [cloud cover photography

    Science.gov (United States)

    Dubenskiy, V. P.; Nemkovskiy, B. L.; Rodionov, B. N.

    1974-01-01

    An electronic transformation and correlation system has been developed for the Meteor space weather system which provides transformation and scaling of the original picture, accounts for satellite flight altitude and inclinations of the optical axes of the transmitting devices, and simultaneously superposes the geographical coordinate grid on the transformed picture.

  15. Compensation for the distortion in satellite laser range predictions due to varying pulse travel times

    Science.gov (United States)

    Paunonen, Matti

    1993-01-01

    A method for compensating for the effect of the varying travel time of a transmitted laser pulse to a satellite is described. The 'observed minus predicted' range differences then appear to be linear, which makes data screening or use in range gating more effective.

  16. Trends In Satellite Communication

    Science.gov (United States)

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.

    1988-01-01

    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  17. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  18. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  19. Biological satellite Kosmos-936

    Science.gov (United States)

    Vedeshin, L. A.

    1978-01-01

    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  20. Small Satellite Transporter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective is to determine whether this small satellite transporter is capable of transporting at least four 6U CubeSats is possible for a given set of...

  1. The Next Landsat Satellite: The Landsat Data Continuity Mission

    Science.gov (United States)

    Rons, James R.; Dwyer, John L.; Barsi, Julia A.

    2012-01-01

    range of human vision. The DOI/USGS is developing the ground system that will command and control the LDCM satellite in orbit and manage the OLI and TIRS data transmitted by the satellite. DOI/USGS will thus operate the satellite and collect, archive, and distribute the image data as part of the EROS archive. DOI/USGS has committed to renaming LDCM as Landsat 8 following launch. By either name the satellite and its sensors will extend the 40-year archive with images sufficiently consistent with data from earlier Landsat satellites to allow multi-decadal, broad-area studies of our dynamic landscapes. The next Landsat satellite and ground system are on schedule for a January, 2013 launch.

  2. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  3. The Archimedes satellite system

    Science.gov (United States)

    Taylor, Stuart C.; Shurvinton, William D.

    1992-03-01

    Archimedes is a satellite system conceived by the European Space Agency (ESA) to effectively serve the European market for Mobile Radio Services (MRS). This paper describes the requirements and technical design of the Archimedes satellite system. The underlying assumptions and trade-offs behind the design are detailed and the design is compared and contrasted against alternative design solutions, both technically and economically. A path forward for the development of the system is indicated.

  4. ASTRID II satellit projekt

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Primdahl, Fritz

    1997-01-01

    The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan.......The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan....

  5. Satellite formation. II

    Science.gov (United States)

    Harris, A. W.

    1978-01-01

    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  6. CHINA LAUNCHES NEW SCIENTIFIC SATELLITE

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China on Sept. 27, 2004 launched a scientific satellite atop a Long March 2D carrier rocket from Jiuquan Satellite Launch Center in Gansu province. 10 minutes after the launch, the satellite entered a preset orbit and is running sound at the orbit. It is the 20th recoverable satellite for scientific and technological

  7. Current Status of Soil-transmitted Nematode Infection in China

    Institute of Scientific and Technical Information of China (English)

    YING-DAN CHEN; LIN-HUA TANG; LONG-QI XU

    2008-01-01

    Objective To Carry out national surveys for ascertaining the current status and trends of soil-transmitted nematode infections in China,providing scientific basis for forther developing control strategies.Methods In 1988-1992(hereinafter abbreriated as "survey in 1990"),a stratified cluster random sampling method was used in the survey.In 2001-2004(hereinafter abbreriated as "survey in 2003"),in order to compare with the survey in 1990,two-characteristic stratified cluster random sampling method was used and 687 investigation spots were sampled from the 2848 spots selected in the survey in 1990.Kato-Katz thick smear method was used to examine the eggs of soil-transmitted nematodes in fecal samples. Results The prevalence rates were 53.6% and 19.6% for soil-transmitted nematodes,14.6%and 6.120% for hookworms,44.6% and 12.7% for Ascaris lumbricoides,17.4% and 4.630% for Trichuris trichiura in survey 1990 and survey 2003,respectively.The prevalence rates of soil-transmitted nematodes were higher in 13 provinces than the average level in China in the survey in 1990.and higher in 8 provinces than the average level in the survey in 2003.The prevalence of hookworms,Ascaris lumbricoides,Trichurls trichiura and the overall prevalence of soft-transmitted nematodes were higher in females than in males.It is estimated from the results of survey in 2003 that the number of persons with soil-transmitted nematode infections in the country is about 129 million,less than that in the survey in 1990. Conclusion The prevalence of soil-transmitted nematodes has declined considerably but is still relatively high in some provinces and autonomous regions.Control activities and socioeconomic development may have contributed to the decreased prevalence.

  8. Satellite Communications for ATM

    Science.gov (United States)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  9. Laser power beaming for satellite applications

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, H.W.

    1993-09-22

    A serious consideration of laser power beaming for satellite applications appears to have grown out of a NASA mission analysis for transmitting power to lunar bases during the two week dark period. System analyses showed that laser power beaming to the moon in conjunction with efficient, large area solar cell collection panels, were an attractive alternative to other schemes such as battery storage and nuclear generators, largely because of the high space transportation costs. The primary difficulty with this scheme is the need for very high average power visible lasers. One system study indicated that lasers in excess of 10 MW at a wavelength of approximately 850 nm were required. Although such lasers systems have received much attention for military applications, their realization is still a long term goal.

  10. Experimental Satellite 2 Successfully Launched

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Small satellite Experimental Satellite 2 (SY-2) was launched by LM-2C launch vehicle from Xichang Satellite Launch Center on Nov. 18, 2004. Later the satellite entered the preset sun-synchronous orbit, which is 700 kilometers above the earth. The launch was the eighthmission this year by China Aerospace Science and Technology Corporation(CASC), which aims to test the technology of the satellite, conduct survey and monitoring of the land and resources and geographical environment on a trial basis.

  11. China's Meteorological Satellite Application System

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiashen

    2008-01-01

    @@ China's meteorological satellite program consists of five systems,namely the satellite system,the launch vehicle system,the launch center system,TT&C and the ground application system.The satellite system consists of FengYun (FY) polar orbiting series and FY geostationary series,which are launched by LM launch vehicles from Taiyan Satellite Launch Center (TSLC) and Xichang Satellite Launch Center (XSLC) respectively.

  12. Influence of sexually transmitted infections in a horse breeding

    Directory of Open Access Journals (Sweden)

    Kosec Marjan

    2015-01-01

    Full Text Available The most frequent problems in horses reproduction are generally divided into those of infectious and non infectious etiology. Common causes of infectious diseases are usual­ly viruses and bacteria, and less frequently protozoa, mykoplasma and fungi. In this work there are presented the most important fact about sexually transmitted diseases, their clinical picture, risk factors, preventive measures as well as measures to prevent and eradicate the diseases. The biggest risk factor for sexually transmitted diseases in horses are breeding stallions, both in natural mating and in artificial insemination. Therefore, in order to prevent genital infections in horses, it is essential that the stallions used for breeding are healthy (non-infected. That can be determined with certainty only if the stallions are examined (tested just before the breeding season on most frequent sexually transmitted diseases (CEM,EAV. It is well known that in most cases the clinical picture of sexually transmitted diseses is not manifested on genitals. As well, variations in clinical picture can be expected also in mares, depending on the stage of the disease and its etiology. Harms arising from sexually transmitted diseases can be divided into direct and indirect. Direct damage occurs in the form of endometritis, miscarriage, stillbirths and births of weak foals, and indirect in restricting the traffic of infected and suspicios animals, isolation of the infected ones as well as medical treatment and interrupting mating.

  13. Decreasing Prevalence of Transfusion Transmitted Infection in Indian Scenario

    Directory of Open Access Journals (Sweden)

    Tulika Chandra

    2014-01-01

    Full Text Available Transfusion transmitted infections are major problem associated with blood transfusion. Accurate estimates of risk of TTIs are essential for monitoring the safety of blood supply and evaluating the efficacy of currently employed screening procedures. The present study was carried out to assess the percentage of voluntary donors and replacement donors and to find out prevalence and changing trends of various TTIs blood donors in recent years. A study was carried out on blood units of voluntary and replacement donors which were collected from January 2008 to December 2012. On screening of 180,371 replacement units, seropositivity of transfusion transmitted disease in replacement donors was 0.15% in HIV, 1.67% in hepatitis B surface antigen, 0.49% in hepatitis C virus, 0.01% in VDRL, and 0.009% in malaria. Of 11,977 voluntary units, seropositivity of transfusion transmitted disease in voluntary donors was 0.08% in HIV, 0.24% in hepatitis B surface antigen, 0.001% in hepatitis C virus, 0.008% in VDRL (sexually transmitted disease, and 0.01% in malaria. From results it has been concluded that prevalence of transfusion transmitted infection (HIV, HBV, HCV, VDRL, and malaria was more in replacement donors in comparison to voluntary donors. Extensive donor selection and screening procedures will help in improving the blood safety.

  14. Decreasing prevalence of transfusion transmitted infection in Indian scenario.

    Science.gov (United States)

    Chandra, Tulika; Rizvi, S Nishat Fatima; Agarwal, Devisha

    2014-01-01

    Transfusion transmitted infections are major problem associated with blood transfusion. Accurate estimates of risk of TTIs are essential for monitoring the safety of blood supply and evaluating the efficacy of currently employed screening procedures. The present study was carried out to assess the percentage of voluntary donors and replacement donors and to find out prevalence and changing trends of various TTIs blood donors in recent years. A study was carried out on blood units of voluntary and replacement donors which were collected from January 2008 to December 2012. On screening of 180,371 replacement units, seropositivity of transfusion transmitted disease in replacement donors was 0.15% in HIV, 1.67% in hepatitis B surface antigen, 0.49% in hepatitis C virus, 0.01% in VDRL, and 0.009% in malaria. Of 11,977 voluntary units, seropositivity of transfusion transmitted disease in voluntary donors was 0.08% in HIV, 0.24% in hepatitis B surface antigen, 0.001% in hepatitis C virus, 0.008% in VDRL (sexually transmitted disease), and 0.01% in malaria. From results it has been concluded that prevalence of transfusion transmitted infection (HIV, HBV, HCV, VDRL, and malaria) was more in replacement donors in comparison to voluntary donors. Extensive donor selection and screening procedures will help in improving the blood safety.

  15. TETRA Backhauling via Satellite: Improving Call Setup Times and Saving Bandwidth

    Directory of Open Access Journals (Sweden)

    Anton Donner

    2014-01-01

    Full Text Available In disaster management scenarios with seriously damaged, not existing, or saturated communication infrastructures satellite communications can be an ideal means to provide connectivity with unaffected remote terrestrial trunked radio (TETRA core networks. However, the propagation delay imposed by the satellite link affects the signalling protocols. This paper discusses the suitability of using a satellite link for TETRA backhauling, introducing two different architectures. In order to cope with the signal delay of the satellite link, the paper proposes and analyzes a suitable solution based on the use of a performance enhancing proxy (PEP. Additionally, robust header compression (ROHC is discussed as suitable technology to transmit TETRA voice via IP-based satellite networks.

  16. Performance Analysis of Integrated Wireless Sensor and Multibeam Satellite Networks Under Terrestrial Interference

    Directory of Open Access Journals (Sweden)

    Hongjun Li

    2016-10-01

    Full Text Available This paper investigates the performance of integrated wireless sensor and multibeam satellite networks (IWSMSNs under terrestrial interference. The IWSMSNs constitute sensor nodes (SNs, satellite sinks (SSs, multibeam satellite and remote monitoring hosts (RMHs. The multibeam satellite covers multiple beams and multiple SSs in each beam. The SSs can be directly used as SNs to transmit sensing data to RMHs via the satellite, and they can also be used to collect the sensing data from other SNs to transmit to the RMHs. We propose the hybrid one-dimensional (1D and 2D beam models including the equivalent intra-beam interference factor β from terrestrial communication networks (TCNs and the equivalent inter-beam interference factor α from adjacent beams. The terrestrial interference is possibly due to the signals from the TCNs or the signals of sinks being transmitted to other satellite networks. The closed-form approximations of capacity per beam are derived for the return link of IWSMSNs under terrestrial interference by using the Haar approximations where the IWSMSNs experience the Rician fading channel. The optimal joint decoding capacity can be considered as the upper bound where all of the SSs’ signals can be jointly decoded by a super-receiver on board the multibeam satellite or a gateway station that knows all of the code books. While the linear minimum mean square error (MMSE capacity is where all of the signals of SSs are decoded singularly by a multibeam satellite or a gateway station. The simulations show that the optimal capacities are obviously higher than the MMSE capacities under the same conditions, while the capacities are lowered by Rician fading and converge as the Rician factor increases. α and β jointly affect the performance of hybrid 1D and 2D beam models, and the number of SSs also contributes different effects on the optimal capacity and MMSE capacity of the IWSMSNs.

  17. Performance Analysis of Integrated Wireless Sensor and Multibeam Satellite Networks Under Terrestrial Interference.

    Science.gov (United States)

    Li, Hongjun; Yin, Hao; Gong, Xiangwu; Dong, Feihong; Ren, Baoquan; He, Yuanzhi; Wang, Jingchao

    2016-10-14

    This paper investigates the performance of integrated wireless sensor and multibeam satellite networks (IWSMSNs) under terrestrial interference. The IWSMSNs constitute sensor nodes (SNs), satellite sinks (SSs), multibeam satellite and remote monitoring hosts (RMHs). The multibeam satellite covers multiple beams and multiple SSs in each beam. The SSs can be directly used as SNs to transmit sensing data to RMHs via the satellite, and they can also be used to collect the sensing data from other SNs to transmit to the RMHs. We propose the hybrid one-dimensional (1D) and 2D beam models including the equivalent intra-beam interference factor β from terrestrial communication networks (TCNs) and the equivalent inter-beam interference factor α from adjacent beams. The terrestrial interference is possibly due to the signals from the TCNs or the signals of sinks being transmitted to other satellite networks. The closed-form approximations of capacity per beam are derived for the return link of IWSMSNs under terrestrial interference by using the Haar approximations where the IWSMSNs experience the Rician fading channel. The optimal joint decoding capacity can be considered as the upper bound where all of the SSs' signals can be jointly decoded by a super-receiver on board the multibeam satellite or a gateway station that knows all of the code books. While the linear minimum mean square error (MMSE) capacity is where all of the signals of SSs are decoded singularly by a multibeam satellite or a gateway station. The simulations show that the optimal capacities are obviously higher than the MMSE capacities under the same conditions, while the capacities are lowered by Rician fading and converge as the Rician factor increases. α and β jointly affect the performance of hybrid 1D and 2D beam models, and the number of SSs also contributes different effects on the optimal capacity and MMSE capacity of the IWSMSNs.

  18. Satellite laser ranging experiment with sub-centimeter single-shot ranging precision at Shanghai Observatory

    Institute of Scientific and Technical Information of China (English)

    YANG; Fumin(杨福民); CHEN; Wanzhen(陈婉珍); ZHANG; Zhongping(张忠萍); CHEN; Juping(陈菊平); HU; Jingfu(扈荆夫); LI; Xin(李鑫); I.; Prochazka; K.; Hamal

    2003-01-01

    The Shanghai Astronomical Observatory, Chinese Academy of Sciences, incollaboration with the Czech Technical University, carried out the experiment of satellite laser ranging with sub-centimeter precision in Shanghai in August 2001. A pico-second event timer was used for the measurement of the time interval between the transmitted and returned laser pulses for Lageos 1, 2, Starlette, Stella, Topex/Poseiden and ERS-2 in coordination with the existing laser transmitting and receiving system at the Shanghai Observatory. The analysis of the measurement showed that the single-shot ranging precision with these satellites is 7-8 mm. In order to compare ranging precision, the existing ranging system has tracked simultaneously these satellites and obtained the ranging precision of 12-15 mm. It means that the ranging precision with the new system is 80% better thanthe existing system. The systematic biases with the existing system have also been checked in the experiment.

  19. The Control of Transmitted Power in an Active Isolation System

    DEFF Research Database (Denmark)

    Elliott, S.J.; Gardonio, P.; Pinnington, R.J.

    1997-01-01

    The isolation of vibration through a system with multiple active mounts is discussed, in which each of the mounts can transmit vibration in several degrees of freedom. Theoretical models of the various parts of this system have been developed which include a flexible receiving structure and distr...... of such an active vibration control system are also discussed.......The isolation of vibration through a system with multiple active mounts is discussed, in which each of the mounts can transmit vibration in several degrees of freedom. Theoretical models of the various parts of this system have been developed which include a flexible receiving structure...... and distributed active mounts, and these models can be connected together to produce an overall theoretical description of a realistic active isolation system. Total transmitted power has been found to be an excellent criterion to quantify the effect of various control strategies in this model in which...

  20. Potential for New York mosquitoes to transmit West Nile virus.

    Science.gov (United States)

    Turell, M J; O'Guinn, M; Oliver, J

    2000-03-01

    We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City Metropolitan Area during the recent (1999) WN outbreak were allowed to feed on chickens infected with WN virus isolated from a crow that had died during this outbreak. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex pipiens mosquitoes were highly susceptible to infection, and nearly all individuals with a disseminated infection did transmit WN virus by bite. In contrast, Aedes vexans were only moderately susceptible to oral infection; however, those individuals inoculated with WN virus did transmit virus by bite.

  1. Infections Transmitted By the Transfusion of Blood and Blood Products

    Directory of Open Access Journals (Sweden)

    Tekin A.

    2011-05-01

    Full Text Available Especially viral hepatitis viruses and human immunodeficiency virus(HIV which were transmitted by the transfusion of blood and blood products have been an important public health problem for a long time on the world. Transfusion of blood and blood products is an ideal and an easiest and a simplest route for transmission of infectious diseases. It is known that many infectious agents, either bacterial, viral, parasitic and fungal agents may be transmitted by the transfusion of blood and blood products. In present study, we reviewed infection diseases that transmitted by the transfusion of blood and blood products.Additionally, we were aimed to emphasize a rare but a very important complication of transfusion of blood and blood products.

  2. System for transmitting and receiving multi-polarized signals

    DEFF Research Database (Denmark)

    2016-01-01

    The present disclosure relates to: an optical receiver, configured to receive at least three multiplexed, differently polarized, optically transmitted signals, each signal associated with a predefined state of polarization, said receiver comprising a multi- polarization analyzer for obtaining...... an analyzed signal for each of said polarized signals, wherein at least one of said analyzed signals comprises data in the full Stokes space; an optical transmitter, configured to transmit at least three multiplexed, differently polarized, optically transmitted signals, wherein at least one of said polarized...... signals comprises data in the full Stokes space; a system configured to communicate optically over a communication link, comprising: an optical transmitter, configured to generate and multiplex at least three independent data signals having different states of polarization into a multiplexed signal...

  3. Transmit antenna selection based on shadowing side information

    KAUST Repository

    Yilmaz, Ferkan

    2011-05-01

    In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

  4. Integrated differential high-voltage transmitting circuit for CMUTs

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Larsen, Dennis Øland; Farch, Kjartan

    2015-01-01

    In this paper an integrated differential high-voltage transmitting circuit for capacitive micromachined ultrasonic transducers (CMUTs) used in portable ultrasound scanners is designed and implemented in a 0.35 μm high-voltage process. Measurements are performed on the integrated circuit in order...... to assess its performance. The circuit generates pulses at differential voltage levels of 60V, 80V and 100 V, a frequency up to 5MHz and a measured driving strength of 1.75 V/ns with the CMUT connected. The total on-chip area occupied by the transmitting circuit is 0.18 mm2 and the power consumption...

  5. Reflecting and transmitting effect of a planar unidirectionally conducting screen

    Institute of Scientific and Technical Information of China (English)

    E Peng; JIANG Bin-hao

    2009-01-01

    The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole. For a dipole oriented along the wire elements of the screen, the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements, the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source, while the transmitted field is arisen from image transmission-line source. The expressions of related surface waves are derived and can be compared with previous results.

  6. Cutaneous diphtheria masquerading as a sexually transmitted disease

    Directory of Open Access Journals (Sweden)

    Vetrichevvel T

    2008-01-01

    Full Text Available A 41 year-old, sexually promiscuous, married male, an agricultural laborer by occupation, presented to our sexually transmitted diseases (STD clinic with multiple ulcers over the scrotum and genitalia of 20 days′ duration. Bacterial culture from swabs taken from the genital ulcer, grew organisms morphologically and biochemically characteristic of Corynaebacterium diphtheriae. He made a complete and uneventful recovery after two weeks of therapy with antidiphtheria serum and crystalline penicillin. This case brings into light this hitherto unreported presentation of wound diphtheria mimicking a sexually transmitted genital ulcer disease and thus, underlines the importance of considering diphtheria as differential in atypical, long-standing genital ulcers.

  7. Solar Power Satellites

    CERN Document Server

    Flournoy, Don M

    2012-01-01

    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  8. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  9. ESA's satellite communications programme

    Science.gov (United States)

    Bartholome, P.

    1985-02-01

    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  10. AVS on satellite

    Science.gov (United States)

    Zhao, Haiwu; Wang, Guozhong; Hou, Gang

    2005-07-01

    AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

  11. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  12. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  13. Declassified intelligence satellite photographs

    Science.gov (United States)

    ,

    1998-01-01

    Recently declassified photographs from spy satellites are an important addition to the record of the Earth?s land surface held by the U.S. Geological Survey (USGS). More than 800,000 high-resolution photos taken between 1959 through 1972 were made available by Executive Order of the President. The collection is held at the USGS EROS Data Center, near Sioux Falls, S. Dak., and are offered for public sale. For some purposes in earth science studies, these photos extend the record of changes in the land surface another decade back in time from the advent of the Landsat earth-observing satellite program.

  14. Oceanography from satellites

    Science.gov (United States)

    Wilson, W. S.

    1981-01-01

    It is pointed out that oceanographers have benefited from the space program mainly through the increased efficiency it has brought to ship operations. For example, the Transit navigation system has enabled oceanographers to compile detailed maps of sea-floor properties and to more accurately locate moored subsurface instrumentation. General descriptions are given of instruments used in satellite observations (altimeter, color scanner, infrared radiometer, microwave radiometer, scatterometer, synthetic aperture radar). It is pointed out that because of the large volume of data that satellite instruments generate, the development of algorithms for converting the data into a form expressed in geophysical units has become especially important.

  15. Satellite oceanography - The instruments

    Science.gov (United States)

    Stewart, R. H.

    1981-01-01

    It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

  16. Integrated Satellite-HAP Systems

    DEFF Research Database (Denmark)

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo

    2005-01-01

    for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite- based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used......Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element...

  17. Conceptual design for a Mercury relativity satellite

    Science.gov (United States)

    Bender, P. L.; Ashby, N.; Wahr, J. M.; Vincent, M. A.

    1989-01-01

    It was shown earlier that 1 x 10 to the -14th Doppler data and 3 cm accuracy range measurements to a small Mercury Relativity Satellite in a polar orbit with four-hour period can give high-accuracy tests of gravitational theory. A particular conceptual design has been developed for such a satellite, which would take less than 10 percent of the approach mass for a possible future Mercury Orbiter Mission. The spacecraft is similar to the Pioneer Venus Orbiter, but scaled down by about a factor four in linear dimensions. A despun antenna 30 cm in diameter is used for tracking. The transmitted power is roughly 0.2 watts at K-band and 0.5 watts at X-band. The orbit parameters for individual eight-hour arcs and the gravity field of Mercury through degree and order 10 are determined mainly from the Doppler data. A 50 MHz K-band sidetone system provides the basic ranging accuracy. The spacecraft mass is 50 kg or less.

  18. Position surveillance using one active ranging satellite and time-of-arrival of a signal from an independent satellite

    Science.gov (United States)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.

    1980-01-01

    Position surveillance using one active ranging/communication satellite and the time-of-arrival of signals from an independent satellite was shown to be feasible and practical. A towboat on the Mississippi River was equipped with a tone-code ranging transponder and a receiver tuned to the timing signals of the GOES satellite. A similar transponder was located at the office of the towing company. Tone-code ranging interrogations were transmitted from the General Electric Earth Station Laboratory through ATS-6 to the towboat and to the ground truth transponder office. Their automatic responses included digital transmissions of time-of-arrival measurements derived from the GOES signals. The Earth Station Laboratory determined ranges from the satellites to the towboat and computed position fixes. The ATS-6 lines-of-position were more precise than 0.1 NMi, 1 sigma, and the GOES lines-of-position were more precise than 1.6 NMi, 1 sigma. High quality voice communications were accomplished with the transponders using a nondirectional antenna on the towboat. The simple and effective surveillance technique merits further evaluation using operational maritime satellites.

  19. Evolution of the NOAA National Weather Service Satellite Broadcast Network (SBN) to Europe's DVB-S satellite communications technology standard

    Science.gov (United States)

    Cragg, Phil; Brockman, William E.

    2006-08-01

    The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) uses a commercial Satellite Broadcast Network (SBN) to distribute weather data to the NWS AWIPS workstations and National Centers and to NWS Family of Service Users. Advances in science and technology from NOAA's observing systems, such as remote sensing satellites and NEXRAD radars, and advances in Numeric Weather Prediction have greatly increased the volume of data to be transmitted via the SBN. The NOAA-NWS SBN Evolution Program did a trade study resulting in the selection of Europe's DVB-S communication protocol as the basis for enabling a significant increase in the SBN capacity. The Digital Video Broadcast (DVB) group, started to develop digital TV for Europe through satellite broadcasting, has become the current standard for defining technology for satellite broadcasting of digital data for much of the world. NOAA-NWS implemented the DVB-S with inexpensive, Commercial Off The Shelf receiving equipment. The modernized NOAA-NWS SBN meets current performance goals and provides the basis for continued future expansion with no increase in current communication costs. This paper discusses aspects of the NOAA-NWS decision and the migration to the DVB-S standard for its commercial satellite broadcasts of observations and Numerical Weather Prediction data.

  20. Satellite orbit determination and gravity field recovery from satellite-to-satellite tracking

    Science.gov (United States)

    Wakker, K. F.; Ambrosius, B. A. C.; Leenman, H.

    1989-07-01

    Studies on satellite-to-satellite tracking (SST) with POPSAT (a geodetic satellite concept) and a ERS-class (Earth observation) satellite, a Satellite-to-Satellite Tracking (SST) gravity mission, and precise gravity field determination methods and mission requirements are reported. The first two studies primarily address the application of SST between the high altitude POPSAT and an ERS-class or GRM (Geopotential Research Mission) satellite to the orbit determination of the latter two satellites. Activities focussed on the determination of the tracking coverage of the lower altitude satellite by ground based tracking systems and by POPSAT, orbit determination error analysis and the determination of the surface forces acting on GRM. The third study surveys principles of SST, uncertainties of existing drag models, effects of direct luni-solar attraction and tides on orbit and the gravity gradient observable. Detailed ARISTOTELES (which replaced POPSAT) orbit determination error analyses were performed for various ground based tracking networks.

  1. The Transmissibility of Sexually Transmitted Diseases in Sexually Abused Children.

    Science.gov (United States)

    Hammerschlag, Margaret R.

    1998-01-01

    This paper summarizes what is known about, and research needs on, the transmissibility to sexually abused children of the following sexually transmitted diseases: gonorrhea, chlamydia trachomatis, human papillomavirus genital warts, condylomata acuminata, syphilis, bacterial vaginosis, trichomonas vaginalis, herpes simplex, and human…

  2. Genetic Analyses of Sorting of Paternally Transmitted Mitochondrial DNA

    Science.gov (United States)

    The organelles are maternally transmitted in the vast majority of eukaryotes. However paternal transmission of plastids and mitochondria occurs rarely in plants. Cucumber is a unique model plant for organellar genetics because its three genomes show differential transmission: maternal for chlorop...

  3. Risk behaviors for sexually transmitted diseases among crack users

    Directory of Open Access Journals (Sweden)

    Rafael Alves Guimarães

    2015-08-01

    Full Text Available AbstractObjectives: to investigate the prevalence and risk behaviors by means of reporting of sexually transmitted diseases among crack users.Method: cross-sectional study carried out with 588 crack users in a referral care unit for the treatment of chemical dependency. Data were collected by means of face-to-face interview and analyzed using Stata statistical software, version 8.0.Results: of the total participants, 154 (26.2%; 95% CI: 22.8-29.9 reported antecedents of sexually transmitted diseases. Ages between 25 and 30 years (RP: 2.1; 95% CI: 1.0-4.0 and over 30 years (RP: 3.8; 95% CI: 2.1-6.8, alcohol consumption (RP: 1.9; 95% CI: 1.1-3.3, antecedents of prostitution (RP: 1.9; 95% CI: 1.3-2.9 and sexual intercourse with person living with human immunodeficiency virus/AIDS (RP: 2.7; 95% CI: 1.8-4.2 were independently associated with reporting of sexually transmitted diseases.Conclusion: the results of this study suggest high risk and vulnerability of crack users for sexually transmitted diseases.

  4. Adolescent Sexuality: Pregnancy, Sexually Transmitted Diseases, and Prevention.

    Science.gov (United States)

    Santelli, John S.; And Others

    1992-01-01

    Special edition discusses adolescent sexuality, focusing on pregnancy, sexually transmitted diseases, and prevention. The articles focus on demographics, risk factors, school-based risk reduction programs, contraception, early intervention, options, school-based prenatal and postpartum care programs, teenage parenting, abortion, HIV and AIDS,…

  5. Sexually transmitted infection incidence among adolescents in Ireland.

    LENUS (Irish Health Repository)

    Davoren, Martin P

    2014-10-01

    The burden of sexually transmitted infections (STIs) rests with young people, yet in Ireland there has been very little research into this population. The purpose of this study was to determine the incidence rate and establish risk factors that predict STI occurrence among adolescents in Ireland.

  6. CONSTRUCTIONS OF THREE-TRANSMIT-ANTENNA SPACE-TIME CODES

    Institute of Scientific and Technical Information of China (English)

    Hongxi TONG; Fei YU

    2007-01-01

    In this paper, we give design methods for three-transmit-antenna space-time codes which have reasonable parameters. A few examples are given to show that some unitary space-time codes constructed with our methods are better than the previously best-known ones.

  7. The Silent Epidemic. Teens and Sexually Transmitted Diseases.

    Science.gov (United States)

    Francis, Susan

    1998-01-01

    One-quarter of the 3 million new cases of sexually transmitted diseases (STDs) each year occur in teenagers. Teens are at high risk because of biological, age, and behavioral factors. Education is the best weapon against STDs. As their children's first sex educators, parents must make every effort to promote STD education at home and school. (SM)

  8. Adaptive single-antenna transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2011-10-01

    This paper studies the performance of adaptive transmit selection with co-channel interference suppression in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to-interference-plus-noise ratios (SINRs). Two interference cancelation algorithms are considered. The first algorithm assumes that the receiver eliminates the impact of the strongest subset of interferers, whereas the second algorithm suggests random cancelation of interferers to further reduce processing complexity. The impact of outdated ordering of interferers powers on the efficiency of interference cancelation, and the effect of imperfect prediction of transmit channels for desired user adaptation are investigated. Analytical formulations for various performance measures and comparisons between the performance and processing complexity of different adaptation schemes are presented. © 2011 IEEE.

  9. HIV and Sexually Transmitted Infections in the Netherlands in 2003

    NARCIS (Netherlands)

    Laar MJW van de; Op de Coul ELM; CIE

    2004-01-01

    The increasing trend of Sexually Transmitted Infections (STIs), as observed in the last few years, seemed to have stabilised in 2003. The continuous increase of syphilis diagnoses and the outbreak of Lymphogranuloma venereum (LGV) among men who have sex with men (MSM), indicate an increase of sexual

  10. Sex Partner with No Zika Symptoms Transmits Virus: CDC

    Science.gov (United States)

    ... news/fullstory_160643.html Sex Partner With No Zika Symptoms Transmits Virus: CDC New report also highlights ties between Zika ... HealthDay News) -- U.S. health officials report that the Zika virus can be spread sexually even when a partner ...

  11. Young Male Prostitutes: Their Knowledge of Selected Sexually Transmitted Diseases.

    Science.gov (United States)

    Calhoun, Thomas; Pickerill, Brian

    1988-01-01

    Conducted unstructured interviews with 18 male street prostitutes between the ages of 13 and 22 to determine the extent of accurate knowledge they possessed concerning four common sexually transmitted diseases. Found that subjects possessed more factual information on gonorrhea and syphilis than on herpes and Acquired Immune Deficiency Syndrome.…

  12. Knowledge of Sexually Transmitted infections among High School Students

    Science.gov (United States)

    Nsuami, M. Jacques; Sanders, Ladatra S.; Taylor, Stephanie N.

    2010-01-01

    Background: It has not been determined conclusively whether greater knowledge of sexually transmitted infections (STIs) is associated with lower rates of STIs. Purpose: This study sought to determine STI knowledge among high school students and factors associated with such knowledge, and to determine whether poor STI knowledge is associated with…

  13. Fourier-Based Transmit Beampattern Design Using MIMO Radar

    KAUST Repository

    Lipor, John

    2014-05-01

    In multiple-input multiple-output (MIMO) radar settings, it is often desirable to transmit power only to a given location or set of locations defined by a beampattern. Transmit waveform design is a topic that has received much attention recently, involving synthesis of both the signal covariance matrix,, as well as the actual waveforms. Current methods involve a two-step process of designing via iterative solutions and then using to generate waveforms that fulfill practical constraints such as having a constant-envelope or drawing from a finite alphabet. In this paper, a closed-form method to design for a uniform linear array is proposed that utilizes the discrete Fourier transform (DFT) coefficients and Toeplitz matrices. The resulting covariance matrix fulfills the practical constraints such as positive semidefiniteness and the uniformelemental power constraint and provides performance similar to that of iterative methods, which require a much greater computation time. Next, a transmit architecture is presented that exploits the orthogonality of frequencies at discrete DFT values to transmit a sum of orthogonal signals from each antenna. The resulting waveforms provide a lower mean-square error than current methods at a much lower computational cost, and a simulated detection scenario demonstrates the performance advantages achieved.

  14. Sexually Transmitted Disease Prevention: Adolescents' Perceptions of Possible Side Effects.

    Science.gov (United States)

    Furby, Lita; Ochs, Linda M.; Thomas, Catherine W.

    1997-01-01

    Reports on interviews of 48 sexually active adolescents concerning the possible secondary consequences of taking measures to reduce the risk of contracting a sexually transmitted disease (STD). Adolescents generated 134 consequences, suggesting that considering all the relevant consequences for a rational decision about STD prevention is not…

  15. The prevalence of transfusion transmitted virus infection in blood donors

    Institute of Scientific and Technical Information of China (English)

    Cheng Hui Huang; Ru Guang Chen; Yu Sen Zhou; Hai Tao Wang; Chun Ying Xie

    2000-01-01

    @@INTRODUCTION A newly discovered DNA virus,transfusion transmitted virus (TTV), was reported as a cause of post-transfusion hepatitis of unknown etiology in Japan[1]. In order to investigate TTV prevalence in southern China, a study was carried out among blood donors, patients with liver diseases and hemodialysis to determine the epidemiological charateristics.

  16. HIV and Sexually Transmitted Infections in the Netherlands in 2005

    NARCIS (Netherlands)

    Boer IM de; Op de Coul ELM; Koedijk FDH; Veen MG van; Sighem AI van; Laar MJW van de; CIE

    2006-01-01

    The trend of increasing Sexually Transmitted Infections (STI) has partly stabilised in 2005 in the STI sentinel surveillance network. Among men having sex with men (MSM), the number of STI diagnoses remained high and the HIV positivity rate has increased. Moreover, in the national HIV registry (HIV

  17. Draft genome sequence of the sexually transmitted pathogen Trichomonas vaginalis

    NARCIS (Netherlands)

    Carlton, Jane M.; Hirt, Robert P.; Silva, Joana C.; Delcher, Arthur L.; Schatz, Michael; Zhao, Qi; Wortman, Jennifer R.; Bidwell, Shelby L.; Alsmark, U. Cecilia M.; Besteiro, Sebastien; Sicheritz-Ponten, Thomas; Noel, Christophe J.; Dacks, Joel B.; Foster, Peter G.; Simillion, Cedric; Van de Peer, Yves; Miranda-Saavedra, Diego; Barton, Geoffrey J.; Westrop, Gareth D.; Mueller, Sylke; Dessi, Daniele; Fiori, Pier Luigi; Ren, Qinghu; Paulsen, Ian; Zhang, Hanbang; Bastida-Corcuera, Felix D.; Simoes-Barbosa, Augusto; Brown, Mark T.; Hayes, Richard D.; Mukherjee, Mandira; Okumura, Cheryl Y.; Schneider, Rachel; Smith, Alias J.; Vanacova, Stepanka; Villalvazo, Maria; Haas, Brian J.; Pertea, Mihaela; Feldblyum, Tamara V.; Utterback, Terry R.; Shu, Chung-Li; Osoegawa, Kazutoyo; de Jong, Pieter J.; Hrdy, Ivan; Horvathova, Lenka; Zubacova, Zuzana; Dolezal, Pavel; Malik, Shehre-Banoo; Logsdon, John M.; Henze, Katrin; Gupta, Arti; Wang, Ching C.; Dunne, Rebecca L.; Upcroft, Jacqueline A.; Upcroft, Peter; White, Owen; Salzberg, Steven L.; Tang, Petrus; Chiu, Cheng-Hsun; Lee, Ying-Shiung; Embley, T. Martin; Coombs, Graham H.; Mottram, Jeremy C.; Tachezy, Jan; Fraser-Liggett, Claire M.; Johnson, Patricia J.

    2007-01-01

    We describe the genome sequence of the protist Trichomonas vaginalis, a sexually transmitted human pathogen. Repeats and transposable elements comprise about two-thirds of the similar to 160-megabase genome, reflecting a recent massive expansion of genetic material. This expansion, in conjunction wi

  18. Sexually transmitted infections, including HIV, in the Netherlands in 2014.

    NARCIS (Netherlands)

    Oeffelen, A.A.M. van; Aar, F. van; Broek, I.V.F. van den; Coul, E.L.M. Op de; Woestenberg, P.J.; Heijne, J.C.M.; Daas, C. den; Hofstraat, S.H.I.; Sighem, A.I. van; Nielen, M.M.J.; Benthem, B.H.B. van

    2015-01-01

    In 2013, more people were tested for sexually transmitted infections (STI) at Dutch STI clinics than in previous years. Although the percentage of people with an STI showed a slight decrease (0.4 per cent) for the first time since 2007, it remained high at 14.7 per cent. Effective STI monitoring

  19. Sexually transmitted infections, including HIV, in the Netherlands in 2013.

    NARCIS (Netherlands)

    Aar, F. van; Koedijk, F.D.H.; Broek, I.V.F. van den; Coul, E.L.M. Op de; Soetens, L.C.; Woestenberg, P.J.; Heijne, J.C.M.; Sighem, A.I. van; Nielen, M.M.J.; Benthem, B.H.B. van

    2014-01-01

    In 2013, more people were tested for sexually transmitted infections (STI) at Dutch STI clinics than in previous years. Although the percentage of people with an STI showed a slight decrease (0.4 per cent) for the first time since 2007, it remained high at 14.7 per cent. Effective STI monitoring

  20. Considerations of digital phase modulation for narrowband satellite mobile communication

    Science.gov (United States)

    Grythe, Knut

    1990-01-01

    The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

  1. An advanced generation land mobile satellite system and its critical technologies

    Science.gov (United States)

    Naderi, F.

    1982-01-01

    A conceptual design for a Land Mobile Satellite System (LMSS) for the 1990s is presented. LMSS involves small tranceivers accessing satellites directly, with ground reception through small car-top antennas. The satellite would have a large antenna and blanket coverage areas in the UHF. The call may originate from a home, be carried by wire to a gateway, transmitted to satellite on the S-band, converted to UHF on the satellite, and transmitted to the vehicle. The system design is constrained by the number of users in an area during the busiest hours, Shuttle storage, controllability factors, and the total area served. A 55-m antenna has been selected, with 87 spot beams and two 10 MHz UHF bands in the 806-890 MHz band. A 17 dB interbeam isolation level is required, implying that sufficient sub-bands can be generated to assure 8265 total channels. The mobile satellite (MSAT) would have an 83 m mast lower segment, a 34 m upper segment, and a second, 10 m antenna made of a deployable mesh. Various antenna function modes are considered.

  2. Man-made Satellites

    Institute of Scientific and Technical Information of China (English)

    郝昌明

    2005-01-01

    If you watch the sky about an hour after the sun goes down, you may see some “moving stars”. But they're not real stars. They're manmade satellites (卫星). And the biggest of all is the International Space Station (ISS国际空间站).

  3. Observations of artificial satellites

    Directory of Open Access Journals (Sweden)

    A. MAMMANO

    1964-06-01

    Full Text Available The following publication gives the results of photographic
    observations of artificial satellites made at Asiago during the second
    and third year of this programme. The fixed camera technique and that
    with moving film (the latter still in its experimental stage have been used.

  4. Experimental Satellite Quantum Communications.

    Science.gov (United States)

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  5. Perception via satellite

    Science.gov (United States)

    Robinove, Charles J.

    1970-01-01

    The earth resources observation satellite (EROS) program in the Department of the Interior is intended to gather and use data from satellites and aircraft on natural and man-made features of the earth's surface. Earth resources technology satellite will provide the EROS program with data for use in dealing with natural resource problems and understanding the interaction between man and the environment. Applications will include studies of tectonic features, hydrologic problems, location of fish schools, determination of the conditions of range land, mapping land use for urban planning, studies of erosion and change along coastlines and major streams, and inventories of land use and land forms. In addition, the ERTS data may be used for detecting forest and crop diseases and inventorying crops. The ERTS satellite will be in a polar, sun-synchronous orbit so that each point on the earth's surface will be sensed every 17 to 20 days, at the same time of day. Multispectral photography is being investigated for its usefulness in hydrology. Side-looking airborne radar has not yet been widely used in hydrologic studies, although it is an excellent tool for all-weather, day or night, coverage of large areas. Other techniques being investigated include passive microwave radiometry, ultraviolet and visible stimulated luminescence, and absorption spectroscopy.

  6. Satellite Photometric Error Determination

    Science.gov (United States)

    2015-10-18

    of nearly specular reflections from most solar panels. Our primary purpose in presenting these two plots is to demonstrate the usefulness of...than a transformation for stars because the spectral energy distribution of satellites can change with phase angle and is subject to specular

  7. Creating Better Satellite Conferences.

    Science.gov (United States)

    Horner, Tommy

    1998-01-01

    Presents four ways to improve broadcasts of company satellite conferences, including creative site selection (using facilities at educational institutions rather than hotel rooms); creative programming (using graphics and other interruptions to break up lectures or speeches); creative crew selection; and creative downlink site activities (to…

  8. Ocean surveillance satellites

    Science.gov (United States)

    Laurent, D.

    Soviet and U.S. programs involving satellites for surveillance of ships and submarines are discussed, considering differences in approaches. The Soviet program began with the Cosmos 198 in 1967 and the latest, the Cosmos 1400 series, 15 m long and weighing 5 tons, carry radar for monitoring ships and a nuclear reactor for a power supply. Other Soviet spacecraft carrying passive microwave sensors and ion drives powered by solar panels have recently been detonated in orbit for unknown reasons. It has also been observed that the Soviet satellites are controlled in pairs, with sequential orbital changes for one following the other, and both satellites then overflying the same points. In contrast, U.S. surveillance satellites have been placed in higher orbits, thus placing greater demands on the capabilities of the on-board radar and camera systems. Project White Cloud and the Clipper Bow program are described, noting the continued operation of the White Cloud spacecraft, which are equipped to intercept radio signals from surface ships. Currently, the integrated tactical surveillance system program has completed its study and a decision is expected soon.

  9. OMV With Satellite

    Science.gov (United States)

    1986-01-01

    This 1986 artist's concept shows the Orbital Maneuvering Vehicle (OMV) towing a satellite. As envisioned by Marshall Space Flight Center plarners, the OMV would be a remotely-controlled free-flying space tug which would place, rendezvous, dock, and retrieve orbital payloads.

  10. Advances in satellite oceanography

    Science.gov (United States)

    Brown, O. B.; Cheney, R. E.

    1983-01-01

    Technical advances and recent applications of active and passive satellite remote sensing techniques to the study of oceanic processes are summarized. The general themes include infrared and visible radiometry, active and passive microwave sensors, and buoy location systems. The surface parameters of sea surface temperature, windstream, sea state, altimetry, color, and ice are treated as applicable under each of the general methods.

  11. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  12. Intimate partner violence after the diagnosis of sexually transmitted diseases.

    Science.gov (United States)

    Andrade, Roumayne Fernandes Vieira; Araújo, Maria Alix Leite; Vieira, Luiza Jane Eyre de Souza; Reis, Cláudia Bastos Silveira; Miranda, Angélica Espinosa

    2015-01-01

    OBJECTIVE To assess the prevalence and factors associated with intimate partner violence after the diagnosis of sexually transmitted diseases. METHODS This cross-sectional study was conducted in Fortaleza, CE, Northeastern Brazil, in 2012 and involved 221 individuals (40.3% male and 59.7% female) attended to at reference health care units for the treatment of sexually transmitted diseases. Data were collected using a questionnaire applied during interviews with each participant. A multivariate analysis with a logistic regression model was conducted using the stepwise technique. Only the variables with a p value sexually transmitted diseases, the following variables remained statistically significant: extramarital relations (OR = 3.72; 95%CI 1.91;7.26; p = 0.000), alcohol consumption by the partner (OR = 2.16; 95%CI 1.08;4.33; p = 0.026), history of violence prior to diagnosis (OR = 2.87; 95%CI 1.44;5.69; p = 0.003), and fear of disclosing the diagnosis to the partner (OR = 2.66; 95%CI 1.32;5.32; p = 0.006). CONCLUSIONS Individuals who had extramarital relations, experienced violence prior to the diagnosis of sexually transmitted disease, feared disclosing the diagnosis to the partner, and those whose partner consumed alcohol had an increased likelihood of suffering violence. The high prevalence of intimate partner violence suggests that this population is vulnerable and therefore intervention efforts should be directed to them. Referral health care services for the treatment of sexually transmitted diseases can be strategic places to identify and prevent intimate partner violence.

  13. Defense Meteorological Satellite Program (DMSP)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Defense Meteorological Satellite Program (DMSP) satellites collect visible and infrared cloud imagery as well as monitoring the atmospheric, oceanographic,...

  14. DFH Satellite Co.,Ltd.

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    DFH Satellite Co.,Ltd. is a hi-tech enterprise founded and sponsored by China Aerospace Science and Technology Corporation(CASC) and one of CASC subsidiaries,China Academy of Space Technology (CAST). The company is mainly engaged in the research and development of small satellites and micro-satellites, Osystem designs and product development for satellite application projects as well as the international exchanges and cooperation.

  15. Trends in sexually transmitted infections in the Netherlands, combining surveillance data from general practices and sexually transmitted infection centers.

    NARCIS (Netherlands)

    Broek, I.V.F. van den; Verheij, R.A.; Dijk, C. van; Koedijk, F.D.H.; Sande, M.A.B. van der; Bergen, J.E.A.M. van

    2010-01-01

    Background: Sexually transmitted infections (STI) care in the Netherlands is primarily provided by general practitioners (GPs) and specialized STI centers. STI surveillance is based on data from STI centers, which show increasing numbers of clients. Data from a GP morbidity surveillance network were

  16. Telelibrary: Library Services via Satellite.

    Science.gov (United States)

    Liu, Rosa

    1979-01-01

    Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

  17. Mobile satellite service for Canada

    Science.gov (United States)

    Sward, David

    1988-05-01

    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  18. Efficient medium access control protocol for geostationary satellite systems

    Institute of Scientific and Technical Information of China (English)

    王丽娜; 顾学迈

    2004-01-01

    This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

  19. Satellite Aerodynamics and Density Determination from Satellite Dynamic Response

    Science.gov (United States)

    Karr, G. R.

    1972-01-01

    The aerodynamic drag and lift properties of a satellite are first expressed as a function of two parameters associated with gas-surface interaction at the satellite surface. The dynamic response of the satellite as it passes through the atmosphere is then expressed as a function of the two gas-surface interaction parameters, the atmospheric density, the satellite velocity, and the satellite orientation to the high speed flow. By proper correlation of the observed dynamic response with the changing angle of attack of the satellite, it is found that the two unknown gas-surface interaction parameters can be determined. Once the gas-surface interaction parameters are known, the aerodynamic properties of the satellite at all angles of attack are also determined.

  20. Intimate partner violence after the diagnosis of sexually transmitted diseases

    Directory of Open Access Journals (Sweden)

    Roumayne Fernandes Vieira Andrade

    2015-01-01

    Full Text Available OBJECTIVE To assess the prevalence and factors associated with intimate partner violence after the diagnosis of sexually transmitted diseases. METHODS This cross-sectional study was conducted in Fortaleza, CE, Northeastern Brazil, in 2012 and involved 221 individuals (40.3% male and 59.7% female attended to at reference health care units for the treatment of sexually transmitted diseases. Data were collected using a questionnaire applied during interviews with each participant. A multivariate analysis with a logistic regression model was conducted using the stepwise technique. Only the variables with a p value < 0.05 were included in the adjusted analysis. The odds ratio (OR with 95% confidence interval (CI was used as the measure of effect. RESULTS A total of 30.3% of the participants reported experiencing some type of violence (27.6%, psychological; 5.9%, physical; and 7.2%, sexual after the diagnosis of sexually transmitted disease. In the multivariate analysis adjusted to assess intimate partner violence after the revelation of the diagnosis of sexually transmitted diseases, the following variables remained statistically significant: extramarital relations (OR = 3.72; 95%CI 1.91;7.26; p = 0.000, alcohol consumption by the partner (OR = 2.16; 95%CI 1.08;4.33; p = 0.026, history of violence prior to diagnosis (OR = 2.87; 95%CI 1.44;5.69; p = 0.003, and fear of disclosing the diagnosis to the partner (OR = 2.66; 95%CI 1.32;5.32; p = 0.006. CONCLUSIONS Individuals who had extramarital relations, experienced violence prior to the diagnosis of sexually transmitted disease, feared disclosing the diagnosis to the partner, and those whose partner consumed alcohol had an increased likelihood of suffering violence. The high prevalence of intimate partner violence suggests that this population is vulnerable and therefore intervention efforts should be directed to them. Referral health care services for the treatment of sexually transmitted diseases can

  1. Intimate partner violence after the diagnosis of sexually transmitted diseases

    Science.gov (United States)

    Andrade, Roumayne Fernandes Vieira; Araújo, Maria Alix Leite; Vieira, Luiza Jane Eyre de Souza; Reis, Cláudia Bastos Silveira; Miranda, Angélica Espinosa

    2015-01-01

    OBJECTIVE To assess the prevalence and factors associated with intimate partner violence after the diagnosis of sexually transmitted diseases. METHODS This cross-sectional study was conducted in Fortaleza, CE, Northeastern Brazil, in 2012 and involved 221 individuals (40.3% male and 59.7% female) attended to at reference health care units for the treatment of sexually transmitted diseases. Data were collected using a questionnaire applied during interviews with each participant. A multivariate analysis with a logistic regression model was conducted using the stepwise technique. Only the variables with a p value < 0.05 were included in the adjusted analysis. The odds ratio (OR) with 95% confidence interval (CI) was used as the measure of effect. RESULTS A total of 30.3% of the participants reported experiencing some type of violence (27.6%, psychological; 5.9%, physical; and 7.2%, sexual) after the diagnosis of sexually transmitted disease. In the multivariate analysis adjusted to assess intimate partner violence after the revelation of the diagnosis of sexually transmitted diseases, the following variables remained statistically significant: extramarital relations (OR = 3.72; 95%CI 1.91;7.26; p = 0.000), alcohol consumption by the partner (OR = 2.16; 95%CI 1.08;4.33; p = 0.026), history of violence prior to diagnosis (OR = 2.87; 95%CI 1.44;5.69; p = 0.003), and fear of disclosing the diagnosis to the partner (OR = 2.66; 95%CI 1.32;5.32; p = 0.006). CONCLUSIONS Individuals who had extramarital relations, experienced violence prior to the diagnosis of sexually transmitted disease, feared disclosing the diagnosis to the partner, and those whose partner consumed alcohol had an increased likelihood of suffering violence. The high prevalence of intimate partner violence suggests that this population is vulnerable and therefore intervention efforts should be directed to them. Referral health care services for the treatment of sexually transmitted diseases can be strategic

  2. Solar power satellites: our next generation of satellites will deliver the sun's energy to Earth

    Science.gov (United States)

    Flournoy, Don M.

    2009-12-01

    The paper addresses the means for gathering energy from sunlight in space and transmitting it to Earth via Solar Power Satellites. The motivating factor is that the output of our sun is the largest potential energy source available, with the capability of providing inexhaustible quantities of clean electrical energy to every location on Earth. The challenge is that considerable financial, intellectual and diplomatic resources must be focused on designing and implementing new types of energy infrastructures in space and on the ground. These include: 1) next-generation space platforms, arrays, and power transmission systems; 2) more flexible and powerful launch vehicles for delivering materials to space; 3) specialized receivers, converters and storage systems on earth, and the in-orbit position allocations, spectrum and software that make these systems work together efficiently and safely.

  3. Address on the Occasion of the Meeting of the Second Committee of Governmental Experts on Problems in the Field of Copyright and of the Protection of Performers, Producers of Phonograms and Broadcasting Organizations Raised by Transmission via Space Satellites.

    Science.gov (United States)

    Maheu, Rene

    These opening remarks by the Director General of Unesco briefly discuss that organization's activities in the area of copyright within the field of satellite communication. They were addressed to members of a committee whose purpose is to determine whether the protection of signals transmitted by communications satellites does or does not require…

  4. Thematic mapping from satellite imagery

    CERN Document Server

    Denègre, J

    2013-01-01

    Thematic Mapping from Satellite Imagery: A Guidebook discusses methods in producing maps using satellite images. The book is comprised of five chapters; each chapter covers one stage of the process. Chapter 1 tackles the satellite remote sensing imaging and its cartographic significance. Chapter 2 discusses the production processes for extracting information from satellite data. The next chapter covers the methods for combining satellite-derived information with that obtained from conventional sources. Chapter 4 deals with design and semiology for cartographic representation, and Chapter 5 pre

  5. Cooperative and cognitive satellite systems

    CERN Document Server

    Chatzinotas, Symeon; De Gaudenzi, Riccardo

    2015-01-01

    Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

  6. BeiDou Satellites Assistant Determination by Receiving Other GNSS Downlink Signals

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2016-01-01

    Full Text Available GNSS’s orbit determinations always rely on ground station or intersatellite links (ISL. In the emergency of satellite-to-ground links and ISL break-off, BeiDou navigation satellite system (BDS satellites cannot determine their orbits. In this paper, we propose to add a spaceborne annular beam antenna for receiving the global positioning system (GPS and global navigation satellite system (GLONASS signals; therefore, the BDS satellites may be capable of determining their orbits by GPS/GLONASS signals. Firstly, the spectrum selection, the power isolation, the range of Doppler frequency shift, and changing rate are taken into account for the feasibility. Specifically, the L2 band signals are chosen for receiving and processing in order to prevent the overlapping of the receiving and transmitting signals. Secondly, the minimum number of visible satellites (MNVS, carrier-to-noise ratio (C/N0, dilution of precision (GDOP, and geometric distance root-mean-square (gdrms are evaluated for acquiring the effective receiving antennas’ coverage ranges. Finally, the scheme of deploying 3 receiving antennas is proved to be optimal by analysis and simulations over the middle earth orbit (MEO, geostationary earth orbit (GEO, and the inclined geosynchronous satellite orbit (IGSO. The antennas’ structures and patterns are designed to draw a conclusion that installing GPS and GLONASS receivers on BDS satellites for emergent orbits determination is cost-effective.

  7. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...

  8. Declassified Intelligence Satellite Photographs

    Science.gov (United States)

    ,

    2008-01-01

    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth's land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive. The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  9. Satellites in Canadian broadcasting

    Science.gov (United States)

    Siocos, C. A.

    The involvement of Canadian broadcasting and related enterprises in satellite telecommunications is surveyed. This includes point-to-point transmissions and direct ones to the general public. The mode of such utilizations is indicated in both these cases. For the forthcoming DBS systems the many types of service offerings and utilization concepts under discussion elasewhere are presented as well as the business prospects and regulatory climate offering them.

  10. Neptune: Minor Satellites

    Science.gov (United States)

    Murdin, P.

    2003-04-01

    All but one of Neptune's minor satellites orbit within or just outside its ringsystem; the exception is the distant object Nereid. Some of them are betterdescribed as `mid-sized' rather than `minor', but are included under thisheading as little is known of them. The inner four, with approximatediameters, are Naiad (60 km), Thalassa (80 km), Despina (150 km) and Galatea(160 km). The first three lie...

  11. Satellite Surveillance: Domestic Issues

    Science.gov (United States)

    2010-02-01

    earthquake and tsunami in the Indian Ocean and Hurricane Katrina in 2005, when the NGA provided graphics for “relief efforts that depicted the locations of...that show the damage resulting from an earthquake , fire, flood, hurricane, oil spill, or volcanic eruption.8 Bush Administration Policies...Satellite information has continued to have important civil applications in such disparate areas as the movement of glaciers in Yakutat Bay in Alaska

  12. Antimicrobial activity of plant extracts against sexually transmitted pathogens.

    Science.gov (United States)

    Jadhav, Nutan; Kulkarni, Sangeeta; Mane, Arati; Kulkarni, Roshan; Palshetker, Aparna; Singh, Kamalinder; Joshi, Swati; Risbud, Arun; Kulkarni, Smita

    2015-01-01

    Comprehensive management of sexually transmitted infections (STIs) using vaginal or rectal microbicide-based intervention is one of the strategies for prevention of HIV infection. Herbal products have been used for treating STIs traditionally. Herein, we present in vitro activity of 10 plant extracts and their 34 fractions against three sexually transmitted/reproductive tract pathogens - Neisseria gonorrhoeae, Haemophilus ducreyi and Candida albicans. The plant parts were selected; the extracts/fractions were prepared and screened by disc diffusion method. The minimum inhibitory and minimum cidal concentrations were determined. The qualitative phytochemical analysis of selected extracts/fractions showing activity was performed. Of the extracts/fractions tested, three inhibited C. albicans, ten inhibited N. gonorrhoeae and five inhibited H. ducreyi growth. Our study demonstrated that Terminalia paniculata Roth. extracts/fractions inhibited growth of all three organisms. The ethyl acetate fraction of Syzygium cumini Linn. and Bridelia retusa (L.) Spreng. extracts was found to inhibit N. gonorrhoeae at lowest concentrations.

  13. Sexually transmitted diseases: epidemiological and clinical aspects in adults.

    Science.gov (United States)

    Siracusano, Salvatore; Silvestri, Tommaso; Casotto, Daniela

    2014-01-01

    Sexually transmitted diseases (STDs) are the first 10 causes of unpleased diseases in young adult women in the world. The concept of STDs includes a series of syndromes caused by pathogens that can be acquired by sexual intercourse or sexual activity.Adolescents and young adults are responsible for only 25% of the sexually active population and they represent almost 50% of all newly acquired STDs.In this way, we evaluated the epidemiological and clinical aspects of most relevant pathogens as Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Haemophilus Ducreyi, Trichomonas vaginalis, herpes simplex virus, human papilloma virus (HPV) with the exception of hepatitis, and HIV infections for which we suggest specific guidelines.To attain this objective, we analyzed the results of epidemiological and clinical aspects of STDs through a review of the literature using MEDLINE and PubMed database for original articles published using the terms "sexual transmitted disease, epidemiology, diagnosis and therapy" from 2005 to 2014.

  14. Three Dimensional Energy Transmitting Boundary in the Time Domain

    Directory of Open Access Journals (Sweden)

    Naohiro eNakamura

    2015-11-01

    Full Text Available Although the energy transmitting boundary is accurate and efficient for the FEM earthquake response analysis, it could be applied in the frequency domain only. In the previous papers, the author proposed an earthquake response analysis method using the time domain energy transmitting boundary for two dimensional problems. In this paper, this technique is expanded for three dimensional problems. The inner field is supposed to be a hexahedron shape and the approximate time domain boundary is explained, first. Next, two dimensional anti-plane time domain boundary is studied for a part of the approximate three dimensional boundary method. Then, accuracy and efficiency of the proposed method are confirmed by example problems.

  15. Transmitting electric power system dynamics in SCADA using polynomial fitting

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The paper proposes an approach to transmit electric power system dynamics in the SCADA. With the prevalent application of digital substation automation system, it is feasible for the remote terminal units (RTUs) to collect phasors within a substation. However, limited communication capacity remains the bottleneck that prevents SCADA from transmitting system dynamics. This paper proposes to compress dynamics data with curve fitting in the RTUs and reconstruct the dynamics in the SCADA server for reducing communication demand. Dispatchers in the control center can thus get system dynamics with a delay of several seconds. Simulation result shows that for a power system under disturbance with short-circuit that once occurred and was cleared, the SCADA can approximate the original dynamics with satisfying precision using limited degree polynomial fitting. The approach is highly scalable and adaptable, and can be implemented on existing communication infrastructure with a few software modifications. The approach has extensive application potential.

  16. Spectrally efficient switched transmit diversity for spectrum sharing systems

    KAUST Repository

    Bouida, Zied

    2011-09-01

    Under the scenario of an underlay cognitive radio network, we propose in this paper an adaptive scheme using switched transmit diversity and adaptive modulation in order to increase the spectral efficiency of the secondary link. The proposed bandwidth efficient scheme (BES) uses the scan and wait (SWC) combining technique where a transmission occurs only when a branch with an acceptable performance is found, otherwise data is buffered. In our scheme, the modulation constellation size and the used transmit branch are determined to achieve the highest spectral efficiency given the fading channel conditions, the required error rate performance, and a peak interference constraint to the primary receiver. Selected numerical examples show that the BES scheme increases the capacity of the secondary link when compared to an existing switching efficient scheme (SES). This spectral efficiency comes at the expense of an increased average number of switched branches and thus an increased average delay. © 2011 IEEE.

  17. Joint Transmit Beamforming and Power Control for CDMA System

    Institute of Scientific and Technical Information of China (English)

    LI Ji-long; CHEN Yu; LI Chun-yuan; ZHANG Ping

    2005-01-01

    Downlink transmit beamforming is a promising technique to reduce interference,and power control is a technique to adjust transmission power to satisfy the link quality.Joint transmission power control and beamforming are proposed to minimize total transmission power.The joint optimization problem is solved by receiver beamforming and power control in virtual uplink.SIR based power control is performed to adjust the power allocation,and transmit beamforming weight vectors are determined by Minimum Variance Distortionless Response(MVDR)criterion.The multipath combining weight vectors are determined by maximum ratio combining criterion.Simulation results show the joint optimization scheme decreases the transmission power,and system performance is enhanced.

  18. Canadian Laboratory Standards for Sexually Transmitted Infections: Best Practice Guidelines

    Directory of Open Access Journals (Sweden)

    Max A Chernesky

    2005-01-01

    Full Text Available Sexually transmitted infections (STI continue to spread, and show no international boundaries. Diseases such as gonorrhea and syphilis, which we thought were under control in Canadian populations, have increased in incidence. Sexually transmitted or associated syndromes such as cervicitis, enteric infections, epididymitis, genital ulcers, sexually related hepatitis, ophthalmia neonatorum, pelvic inflammatory disease, prostatitis and vulvovaginitis present a challenge for the physician to identify the microbial cause, treat the patient and manage contacts. During the past 10 years, new technologies developed for the diagnosis of STIs have provided a clearer understanding of the real accuracy of traditional tests for the diagnosis of infections caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, herpes simplex viruses, hepatitis B virus, human papillomaviruses, HIV, Haemophilus ducreyi, Trichomonas vaginalis and mycoplasmas. This has presented a major challenge to the diagnostic laboratory, namely, selecting the most sensitive and specific test matched with the most appropriate specimens to provide meaningful and timely results to facilitate optimal patient care.

  19. PAPR Reduction in OFDM Using Partial Transmit Sequence (PTS

    Directory of Open Access Journals (Sweden)

    R.Gayathri

    2013-04-01

    Full Text Available In recent years, OFDM has gained a lot of interest in diverse-digital communication applications. This has been due to its favorable properties like high spectral efficiency and robustness to channel fading. Some of the major drawbacks in OFDM are its high peak-to-average-power ratio(PAPR of the transmitted signals and the synchronization of signals. OFDM consist of large number of independent subcarriers, as a result of which the amplitude of such a signal can have high peak values. Coding, phase rotation and clipping are among many PAPR reduction schemes that have been proposed to overcome this problem. Significant reduction in PAPR has been achieved using Partial Transmit Sequence(PTS which comes under Signal scrambling techniques.

  20. Environmental pollution with soil-transmitted helminths in Sanliurfa, Turkey

    Directory of Open Access Journals (Sweden)

    Ulukanligil Mustafa

    2001-01-01

    Full Text Available Soil transmitted helminth (STH infection are endemic in developing countries. A study was carried out of sewage farms, streams and vegetables to determine the sources and routes of STH infection in Sanliurfa, Turkey. Stool samples from farmhouse inhabitants as well as soil and vegetable samples from the gardens were collected and examined. In addition, water samples from streams and vegetable samples from the city market were collected and examined. One hundred and eighty-seven (59.5% of a total of 314 samples, including 88.4% of the stool samples, 60.8% of the water samples, 84.4% of the soil samples and 14% of the vegetable samples, were found to be positive for STH eggs. These results indicate that the water, soil and vegetables are heavily contaminated, and suggest a vicious circle between humans and the environment. Improving environmental sanitation is imperative for the control of soil-transmitted helminthiasis in Sanliurfa.

  1. Update on strategies of controlling sexually transmitted infections: Taiwan experience

    Directory of Open Access Journals (Sweden)

    Chia-Chun Tsai

    2016-09-01

    Full Text Available Sexually transmitted infections (STIs are a variety of clinical infectious conditions caused by pathogens that are transmitted through sexual activity. In recent years, the incidence of STIs has been gradually rising, according to the statistics of the World Health Organization. Although the recommended management of people who have, or are at risk, for STIs were provided by the association of Europe and the United States, the pathogens of STIs still have a great diversity of epidemiology in different ethnic communities and countries. However, to our knowledge, there have been very few studies updating the status of STIs in the Taiwan population. In this article, we focus on evaluations and announcements for common pathogens of STIs in Taiwan. The strategies for prevention and control of STIs are also discussed in this article. We hope that our experience can be shared to the neighboring countries and lead to an Asian consensus of STI.

  2. Bistatic MIMO Radar Clutter Suppression by Exploiting the Transmit Angle

    Directory of Open Access Journals (Sweden)

    Li Jun

    2014-04-01

    Full Text Available The transmit angle of bistatic radars can be obtained by introducing Multiple-Input Multiple-Output (MIMO radar techniques. The Three-Dimensional (3D clutter spectra, that is, the transmit angle, receive angle, and Doppler frequency, are introduced using the additional angle information to Space-Time Adaptive Processing (STAP. This study reviews the researches on bistatic MIMO-STAP. 3D space-time adaptive processing methods for airborne bistatic side-looking MIMO radars, such as 3D-LCMV, 3D-ACR, 3D-JDL, and 3D projection-based reduced dimensional STAP methods, are discussed. Simulation results show that the proposed methods can improve the small-sample support performance of range-dependent clutter suppression in bistatic side-looking MIMO radar. Finally, the results are summarized and the prospects of bistatic MIMO-STAP are discussed.

  3. Current status of soil-transmitted helminths in Vietnam

    DEFF Research Database (Denmark)

    van der Hoek, Wim; De, Nguyen Van; Konradsen, Flemming

    2003-01-01

    This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris (prevale......This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris...... is more evenly distributed throughout the country, but is concentrated in peri-urban and rural agricultural areas. Vegetable cultivation in which nightsoil is used as fertilizer is a risk factor for hookworm infection, especially among adult women. Helminth control programs should be targeted at school...

  4. Exploiting Intimate Relationships: Controlling Mosquito-Transmitted Disease with Wolbachia.

    Science.gov (United States)

    Caragata, Eric P; Dutra, Heverton L C; Moreira, Luciano A

    2016-03-01

    Mosquito-transmitted diseases impose a growing burden on human health, and current control strategies have proven insufficient to stem the tide. The bacterium Wolbachia is a novel and promising form of control for mosquito-transmitted disease. It manipulates host biology, restricts infection with dengue and other pathogens, and alters host reproduction to promote rapid spread in the field. In this review, we examine how the intimate and diverse relationships formed between Wolbachia and their mosquito hosts can be exploited for disease control purposes. We consider these relationships in the context of recent developments, including successful field trials with Wolbachia-infected mosquitoes to combat dengue, and new Wolbachia infections in key malaria vectors, which have enhanced the disease control prospects of this unique bacterium. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Design of HTS transmit filter using step impedance resonators

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, N., E-mail: nsekiya@yamanashi.ac.j [University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Nakagawa, Y. [University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Ohshima, S. [Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)

    2010-11-01

    We have designed a high-temperature superconducting (HTS) transmit filter with step impedance resonators (SIRs). A transmit filter using half-wavelength straight-line resonators requires substantial spacing between adjacent resonators. This means that the filter needs a large substrate and that the number of poles is limited. Using SIRs overcomes this problem because SIRs are compact and have weak coupling. An electromagnetic simulator based on the moment method was used to design the SIR filter, which has a center frequency of 5 GHz and a bandwidth of 120 MHz. Simulation showed that it is approximately 19% smaller than a conventional half-wavelength straight-line resonator filter. Additionally, the maximum surface current is approximately 17% less than that of the conventional filter.

  6. A longitudinal examination of sexually transmitted infection/HIV prevention knowledge and sexually transmitted infections among African-American adolescent females.

    Science.gov (United States)

    Voisin, Dexter R; Tan, Kevin; DiClemente, Ralph J

    2013-12-01

    This study examines whether sexually transmitted infection prevention knowledge predicts the acquisition of biologically confirmed sexually transmitted infections among African-American adolescent females. A total of 715 females were recruited from public health clinics in Atlanta, Georgia, and using audio computer-assisted self-interview technology, we assessed for demographics, sexually transmitted infection prevention knowledge, risky sexual behaviors, and sexually transmitted infections. After controlling for demographics and prior risky sexual behaviors, participants with high prevention knowledge were 0.09 times less likely to report sexually transmitted infections, and those with multiple sexual partners were 1.3 times more likely to report sexually transmitted infections. Our findings suggest that the promotion of accurate sexually transmitted prevention knowledge is critical especially among females with multiple sex partners.

  7. Communications satellites - The experimental years

    Science.gov (United States)

    Edelson, B. I.

    1983-10-01

    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  8. Tethered satellite design

    Science.gov (United States)

    Manarini, G.

    1986-01-01

    The capability of the satellite to perform a variety of space operations to be accomplished from the shuttle is reviewed considering use of the satellite with man-in-loop and closed loop modes and deployment (toward or away from Earth, up to 100 km), stationkeeping, retrieval and control of the satellite. Scientific payloads are to be used to perform experiments and scientific investigation for applications such as magnetometry, electrodynamics, atmospheric science, chemical release, communications, plasmaphysics, dynamic environment, and power and thrust generation. The TSS-S will be reused for at least 3 missions after reconfiguration and refurbishment by changing the peculiar mission items such as thermal control, fixed boom for experiments, aerodynamic tail for yaw attitude control, external skin, experiments, and any other feature. The TSS-S is to be composed of three modules in order to allow independent integration of a single module and to facilitate the refurbishment and reconfiguration between flights. The three modules are service, auxiliary propulsion, and payload modules.

  9. Heart Monitoring By Satellite

    Science.gov (United States)

    1978-01-01

    The ambulance antenna shown is a specially designed system that allows satellite-relayed two-way communications between a moving emergency vehicle and a hospital emergency room. It is a key component of a demonstration program aimed at showing how emergency medical service can be provided to people in remote rural areas. Satellite communication permits immediate, hospital- guided treatment of heart attacks or other emergencies by ambulance personnel, saving vital time when the scene of the emergency is remote from the hospital. If widely adopted, the system could save tens of thousands of lives annually in the U.S. alone, medical experts say. The problem in conventional communication with rural areas is the fact that radio signals travel in line of sight. They may be blocked by tall buildings, hills and mountains, or even by the curvature of the Earth, so signal range is sharply limited. Microwave relay towers could solve the problem, but a complete network of repeater towers would be extremely expensive. The satellite provides an obstruction-free relay station in space.

  10. Tactical Satellite 3

    Science.gov (United States)

    Davis, T. M.; Straight, S. D.; Lockwook, R. B.

    2008-08-01

    Tactical Satellite 3 is an Air Force Research Laboratory Science and Technology (S&T) initiative that explores the capability and technological maturity of small, low-cost satellites. It features a low cost "plug and play" modular bus and low cost militarily significant payloads - a Raytheon developed Hyperspectral imager and secondary payload data exfiltration provided by the Office of Naval Research. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a potential concept of operations for future acquisitions. The key objectives are rapid launch and on-orbit checkout, theater commanding, and near-real time theater data integration. It will also feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the satellite modular bus initiative. Planned for a late summer 2008 launch, the TacSat-3 spacecraft will collect and process images and then downlink processed data using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. An international program, the United Kingdom Defence Science and Technology Laboratory (DSTL) and Australian Defence Science and Technology Organisation (DSTO) plan to participate in TacSat-3 experiments.

  11. A satellite anemometer

    Science.gov (United States)

    Hanson, W. B.; Heelis, R. A.

    1995-01-01

    This report describes the design, development, and testing of components of a satellite anemometer, an instrument for measuring neutral winds in the upper atmosphere from a satellite platform. The device, which uses four nearly identical pressure sensors, measures the angle of arrival of the bulk neutral flow in the satellite frame of reference. It could also be used in a feedback loop to control spacecraft attitude with respect to the ram velocity direction. We have now developed miniaturized ionization pressure gauges that will work well from the slip flow region near 115 km up to the base of the exosphere, which covers the entire altitude range currently being considered for Tether. Laboratory tests have demonstrated a very linear response to changes in ram angle out to +/- 20 deg. (transverse wind component of 2.7 km s(exp -1)) from the ram, and a monotonic response to out beyond 45 deg. Pitch (vertical wind) and yaw (horizontal wind) can be sampled simultaneously and meaningfully up to 10 Hz. Angular sensitivity of 30 arc seconds (approximately 1 ms(exp -1) is readily attainable, but absolute accuracy for winds will be approximately 1 deg (130 m/s) unless independent attitude knowledge is available. The critical elements of the design have all been tested in the laboratory.

  12. Binary Satellite Galaxies

    CERN Document Server

    Evslin, Jarah

    2013-01-01

    Suggestions have appeared in the literature that the following five pairs of Milky Way and Andromeda satellite galaxies are gravitationally bound: Draco and Ursa Minor, Leo IV and V, Andromeda I and III, NGC 147 and 185, and the Magellanic clouds. Under the assumption that a given pair is gravitationally bound, the Virial theorem provides an estimate of its total mass and so its instantaneous tidal radius. For all of these pairs except for the Magellanic clouds the resulting total mass is 2 to 4 orders of magnitude higher than that within the half light radius. Furthermore in the case of each pair except for Leo IV and Leo V, the estimated tidal radius is inferior to the separation between the two satellites. Therefore all or almost all of these systems are not gravitationally bound. We note several possible explanations for the proximities and similar radial velocities of the satellites in each pair, for example they may have condensed from the same infalling structure or they may be bound by a nongravitatio...

  13. Annual US Air Force Sexually Transmitted Disease (STD) Report, 1995.

    Science.gov (United States)

    1996-05-01

    This report evaluates the 1995 US Air Force (USAF) Sexually Transmitted Diseases ( STD ) Prevention and Control Program. The report analyzes data from...88 medical treatment facilities worldwide and compares 1995 data with that from 1992-94. The 1995 USAF active duty total STD incidence rate was 7.64...cases per 1,000 personnel. This rate represents a 18.9% decline from the 1994 reported STD incidence rate of 9.41 per 1,000 personnel. Among active

  14. Using Piezoelectric Devices to Transmit Power through Walls

    Science.gov (United States)

    Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi

    2008-01-01

    A method denoted wireless acoustic-electric feed-through (WAEF) has been conceived for transmitting power and/or data signals through walls or other solid objects made of a variety of elastic materials that could be electrically conductive or nonconductive. WAEF would make it unnecessary to use wires, optical fibers, tubes, or other discrete wall-penetrating signal-transmitting components, thereby eliminating the potential for structural weakening or leakage at such penetrations. Avoidance of such penetrations could be essential in some applications in which maintenance of pressure, vacuum, or chemical or biological isolation is required. In a basic WAEF setup, a transmitting piezoelectric transducer on one side of a wall would be driven at resonance to excite ultrasonic vibrations in the wall. A receiving piezoelectric transducer on the opposite side of the wall would convert the vibrations back to an ultrasonic AC electric signal, which would then be detected and otherwise processed in a manner that would depend on the modulation (if any) applied to the signal and whether the signal was used to transmit power, data, or both. An electromechanical-network model has been derived as a computationally efficient means of analyzing and designing a WAEF system. This model is a variant of a prior model, known in the piezoelectric-transducer art as Mason's equivalent-circuit model, in which the electrical and mechanical dynamics, including electromechanical couplings, are expressed as electrical circuit elements that can include inductors, capacitors, and lumped-parameter complex impedances. The real parts of the complex impedances are used to account for dielectric, mechanical, and coupling losses in all components (including all piezoelectric-transducer, wall, and intermediate material layers). In an application to a three-layer piezoelectric structure, this model was shown to yield the same results as do solutions of the wave equations of piezoelectricity and acoustic

  15. Extension of migration velocity analysis to transmitted wavefields

    Science.gov (United States)

    Lameloise, Charles-Antoine; Chauris, Hervé

    2016-10-01

    Migration velocity analysis aims at automatically updating the large-scale components of the velocity model, called macromodel. Extended Common Image Gathers are panels used to evaluate focusing after imaging and are constructed as a function of a spatial shift introduced in the imaging condition. We investigate how transmitted waves can also be used in migration velocity analysis: instead of back-propagating the residuals associated with reflected waves, we propose to back-propagate the full wavefield. The image function, equivalent to the migrated section for reflected data, does not exhibit localized events in space along horizons but is still sensitive to the choice of the background velocity model and can thus be coupled to the same objective function defined in the image domain. In order to enhance the benefits of direct waves, we consider a cross-well configuration. Direct waves provide a large illumination between two vertical wells. Associated Common Image Gathers present different characteristics than the ones associated with reflected waves in surface acquisition. In particular, energy is spread over up to the maximum penetration depth. We invert cross-well seismic data along two lines. In the first case, the input data contain the full wavefield dominated by transmitted waves. It demonstrates the possibility to handle transmitted waves to determine the velocity model. It appears that the misfit in the data domain is largely reduced after inversion. In the second case, we use the same algorithm, but with reflected observed data only, as in a classical approach. Most of velocity updates are localized around the reflectivity, leading to an incorrect final model. This demonstrates the benefit of transmitted waves for migration velocity analysis in a cross-well configuration.

  16. Culex mosquitoes are experimentally unable to transmit Zika virus

    Science.gov (United States)

    Amraoui, Fadila; Atyame-Nten, Célestine; Vega-Rúa, Anubis; Lourenço-de-Oliveira, Ricardo; Vazeille, Marie; Failloux, Anna Bella

    2016-01-01

    We report that two laboratory colonies of Culex quinquefasciatus and Culex pipiens mosquitoes were experimentally unable to transmit ZIKV either up to 21 days post an infectious blood meal or up to 14 days post intrathoracic inoculation. Infectious viral particles were detected in bodies, heads or saliva by a plaque forming unit assay on Vero cells. We therefore consider it unlikely that Culex mosquitoes are involved in the rapid spread of ZIKV. PMID:27605159

  17. Are adolescents being screened for sexually transmitted diseases?

    OpenAIRE

    Ellen, Jonathan M.; Lane, Margo A; McCright, Jacque

    2000-01-01

    Objectives To determine the proportion of sexually experiencedAfrican American adolescents who report having been screened for sexually transmitted diseases and to determine the proportion who report having been screened for these diseases among adolescents who have had a preventive primary health care visit in the past 2 years. Methods A telephone survey of a population-based sample of African American adolescents aged 12 to17 years residing in a low-income neighborhood in San Francisco with...

  18. An Overview of Algorithms for Downlink Transmit Beamforming

    Science.gov (United States)

    2007-11-02

    Swindlehurst Electrical & Computer Engineering Brigham Young University Vector Modulo Pre-coding Use a perturbation of the form SP =,Cc =t(a+ jb) where -c...constellation "spacing" A. Lee Swindlehurst Electrical & Computer Engineering Brigham Young University Vector Modulo Pre-coding (cont.) * Choose c to solve...An Overview of Algorithms for Downlink Transmit Beamforming A. Lee Swindlehurst and Chris Peel Brigham Young University phone: 801-422-4343 email

  19. Transfusion-Transmitted Babesiosis During Total Hip Arthroplasty.

    Science.gov (United States)

    Carnevale, Joseph; Feller, Ross; Shalvoy, Robert M

    2015-09-01

    Babesiosis is a potentially life-threatening zoonotic disease that is endemic to the northeastern United States and increasing in prevalence worldwide. Transmitted by the same Ixodes tick responsible for Lyme disease, the intraerythrocytic parasite Babesia causes a wide range of clinical presentations--from asymptomatic carriage to a fulminant course with rapid deterioration. Symptoms typically present 1 to 6 weeks after inoculation, with the gradual onset of fatigue, malaise, weakness, and intermittent or sustained fever as high as 40.9°C. Severe cases are associated with parasitemia greater than 4%, alkaline phosphatase greater than 125 U/L, and white blood cell counts greater than 5×10(9)/L. Definitive diagnosis is made by microscopic examination of thin blood smears, polymerase chain reaction, and indirect immunofluorescent antibody testing. The increasing frequency of babesiosis paired with a lack of blood-donor screening assays poses a serious threat to the safety of the US blood supply. Although babesiosis is responsible for 3.6% of transfusion-related deaths, the Food and Drug Administration has yet to approve mandatory screening for the parasite in donated blood. Historically, transfusion-transmitted babesiosis has been thought to be isolated to the immunocompromised patient population. However, a recent case of transfusion-transmitted babesiosis in an immunocompetent patient following total hip arthroplasty is the first reported in the literature and may represent a growing risk to a far greater segment of the population than previously thought. This article summarizes the current state of transfusion-transmitted babesiosis and the detrimental impact of this infection on blood transfusion safety. Copyright 2015, SLACK Incorporated.

  20. General aspects concerning strictly meat and fish transmitted parasitic infections

    OpenAIRE

    Daniele Crotti; Silvia Crotti; Andrea Gustinelli

    2012-01-01

    All helminths parasitosis transmitted to humans trough ingestion of infested fleshes, where man is definitive host too, are represented by four groups of helminths: the cestodes Dyphyllobothrium spp and Spirometra spp. (Sparganum proliferum is the name of the immature plerocercoid larva), the trematodes Opisthorchis Clonorchis “group” (many could be the genera and species involved), and the nematode Capillaria philippinensis. So, for fishes humans foods (fresh or salted water) the control and...

  1. Interferometric SAR imaging by transmitting stepped frequency chaotic noise signals

    Science.gov (United States)

    Zhang, Yunhua; Gu, Xiang; Zhai, Wenshuai; Dong, Xiao; Shi, Xiaojin; Kang, Xueyan

    2015-10-01

    Noise radar has been applied in many fields since it was proposed more than 50 years ago. However, it has not been applied to interferometric SAR imaging yet as far as we know. This paper introduces our recent work on interferometric noise radar. An interferometric SAR system was developed which can transmit both chirp signal and chaotic noise signal (CNS) at multiple carrier frequencies. An airborne experiment with this system by transmitting both signals was carried out, and the data were processed to show the capability of interferometric SAR imaging with CNS. The results shows that although the interferometric phase quality of CNS is degraded due to the signal to noise ratio (SNR) is lower compared with that of chirp signal, we still can get satisfied DEM after multi-looking processing. Another work of this paper is to apply compressed sensing (CS) theory to the interferometric SAR imaging with CNS. The CS theory states that if a signal is sparse, then it can be accurately reconstructed with much less sampled data than that regularly required according to Nyquist Sampling Theory. To form a structured random matrix, if the transmitted signal is of fixed waveform, then random subsampling is needed. However, if the transmitted signal is of random waveform, then only uniform subsampling is needed. This is another advantage of noise signal. Both the interferometric phase images and the DEMs by regular method and by CS method are processed with results compared. It is shown that the degradation of interferometric phases due to subsampling is larger than that of amplitude image.

  2. Human bubonic plague transmitted by a domestic cat scratch.

    Science.gov (United States)

    Weniger, B G; Warren, A J; Forseth, V; Shipps, G W; Creelman, T; Gorton, J; Barnes, A M

    1984-02-17

    Bubonic plague was transmitted to a 10-year-old girl in Oregon by a scratch wound inflicted by a domestic cat. The cat probably was infected by contact with infected wild rodents or their fleas. Yersinia pestis was identified in Diamanus montanus fleas collected from an abandoned burrow near the patient's home. Domestic cats may infect humans with Y pestis by inoculation from a scratch.

  3. Adaptive Distributed Load Balancing Routing Mechanism for LEO Satellite IP Networks

    Directory of Open Access Journals (Sweden)

    Xiao Ma

    2014-04-01

    Full Text Available LEO (Low Earth Orbit satellite constellation is an ideal scheme for the next generation wideband internet. The constellation is formed as a mesh-like network with inter satellite links (ISLs which are equipped between the neighbor satellites for transmitting directly. As to the future wideband IP services, an efficient routing mechanism will play an important role in improving the performance and balancing the network traffic. An Adaptive Distributed Load Balancing Routing Mechanism (ADLB is proposed in this paper to address the above-mentioned issues. This mechanism makes well-performed routing decision based on the current and historical status of each ISLs in each satellite node. With collecting historical information from network initiated, a proper mechanism is contained in ADLB for making required computing power and storage space in a reasonable range. The performance of ADLB is verified via a series of simulations which demonstrate that the scheme can provide better throughput and lower packet drop rate.

  4. Cochannel and Adjacent-Channel Interference in Nonlinear Minimum-Shift-Keyed Satellite System

    Science.gov (United States)

    Yu, John

    1995-01-01

    The interference susceptibility of a serial-minimum-shift-keyed (SMSK) modulation system to an interfering signal transmitted through a satellite link with cascaded nonlinear elements was investigated through computer simulation. The satellite link evaluated in this study represented NASA's Advanced Communications Technology Satellite (ACTS) system. Specifically, nonlinear characteristics were used that had specified amplitude-modulation to amplitude-modulation and amplitude-modulation to phase-modulation transfer characteristics obtained from the actual ACTS hardware. Two measurement scenarios were analyzed: degradation of an MSK satellite link from cochannel interference and from adjacent-channel interference. Interference was evaluated in terms of the probability of bit error rate (BER) versus energy per bit over noise power density Eb/No.

  5. Interaction of the tick immune system with transmitted pathogens

    Science.gov (United States)

    Hajdušek, Ondřej; Šíma, Radek; Ayllón, Nieves; Jalovecká, Marie; Perner, Jan; de la Fuente, José; Kopáček, Petr

    2013-01-01

    Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes is likely mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia), rickettsiae (Anaplasma), and protozoans (Babesia). Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens. PMID:23875177

  6. Interaction of the tick immune system with transmitted pathogens

    Directory of Open Access Journals (Sweden)

    Ondrej eHajdusek

    2013-07-01

    Full Text Available Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes seems to be mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia, rickettsiae (Anaplasma, and protozoans (Babesia. Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens.

  7. Imperfect generalized transmit beamforming with co-channel interference cancelation

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-10-01

    The performance of a generalized single-stream transmit beamforming scheme employing receive co-channel interference -steering algorithms in slowly varying and flat fading channels is analyzed. The impact of imperfect prediction of channel state information (CSI) for the desired user spatially uncorrelated transmit channels is considered. Both dominant interference cancelation and adaptive arbitrary interference cancelation algorithms for closely spaced receive antennas are used. The impact of outdated statistical ordering of the interferers instantaneous powers on the effectiveness of dominant interference cancelation is investigated against the less complex adaptive arbitrary cancelation scheme. For the system models described above, new exact formulas for the statistics of combined signal-to-interference-plus-noise ratio (SINR) are derived, from which results for conventional maximum ratio transmission (MRT) and best transmit channel selection schemes can be deduced as limiting cases. The results presented herein can be used to obtain quantitative measure for various performance metrics, and in addition to investigate the performance-complexity tradeoff for different multiple-antenna system models. © 2010 IEEE.

  8. Culex pipiens quinquefasciatus: a potential vector to transmit Zika virus.

    Science.gov (United States)

    Guo, Xiao-Xia; Li, Chun-Xiao; Deng, Yong-Qiang; Xing, Dan; Liu, Qin-Mei; Wu, Qun; Sun, Ai-Juan; Dong, Yan-de; Cao, Wu-Chun; Qin, Cheng-Feng; Zhao, Tong-Yan

    2016-09-07

    Zika virus (ZIKV) has become a threat to global health since the outbreak in Brazil in 2015. Although ZIKV is generally considered an Aedes-transmitted pathogen, new evidence has shown that parts of the virus closely resemble Culex-transmitted viruses. Therefore, it is important to evaluate the competence of Culex species for ZIKV to understand their potential as vectors. In this study, female Culex pipiens quinquefasciatus were orally exposed to ZIKV. Mosquito midguts, salivary glands and ovaries were tested for ZIKV to measure infection and dissemination at 2, 4, 6, 8, 12, 16 and 18 days post exposure (pe). In addition, saliva was collected from mosquitoes after infection and infant mice were bitten by infected mosquitoes to measure the transmission ability of Cx. p. quinquefasciatus. The results showed that the peak time of virus appearance in the salivary glands was day 8 pe, with 90% infection rate and an estimated virus titer of 3.92±0.49 lg RNA copies/mL. Eight of the nine infant mice had positive brains after being bitten by infected mosquitoes, which meant that Cx. p. quinquefasciatus could be infected with and transmit ZIKV following oral infection. These laboratory results clearly demonstrate the potential role of Cx. p. quinquefasciatus as a vector of ZIKV in China. Because there are quite different vector management strategies required to control Aedes (Stegomyia) species and Cx. p. quinquefasciatus, an integrated approach may be required should a Zika epidemic occur.

  9. MIMO Radar Transmit Beampattern Design Without Synthesising the Covariance Matrix

    KAUST Repository

    Ahmed, Sajid

    2013-10-28

    Compared to phased-array, multiple-input multiple-output (MIMO) radars provide more degrees-offreedom (DOF) that can be exploited for improved spatial resolution, better parametric identifiability, lower side-lobe levels at the transmitter/receiver, and design variety of transmit beampatterns. The design of the transmit beampattern generally requires the waveforms to have arbitrary auto- and crosscorrelation properties. The generation of such waveforms is a two step complicated process. In the first step a waveform covariance matrix is synthesised, which is a constrained optimisation problem. In the second step, to realise this covariance matrix actual waveforms are designed, which is also a constrained optimisation problem. Our proposed scheme converts this two step constrained optimisation problem into a one step unconstrained optimisation problem. In the proposed scheme, in contrast to synthesising the covariance matrix for the desired beampattern, nT independent finite-alphabet constantenvelope waveforms are generated and pre-processed, with weight matrix W, before transmitting from the antennas. In this work, two weight matrices are proposed that can be easily optimised for the desired symmetric and non-symmetric beampatterns and guarantee equal average power transmission from each antenna. Simulation results validate our claims.

  10. Switch and examine transmit diversity for spectrum sharing systems

    KAUST Repository

    Abdallah, Mohamed M.

    2011-06-01

    In this paper, we develop a switch and examine transmit diversity algorithm for spectrum sharing cognitive networks. We consider a cognitive network composed of a primary link that employs constant rate and constant power transmission scheme with automatic-and-repeat request (ARQ) protocol, while the secondary link is composed of a fixed power multiple-antenna secondary transmitter and a single antenna receiver. Our objective is to develop a low complex transmit diversity algorithm at the secondary transmitter that maximizes the performance of the secondary link in terms of the effective throughput while maintaining a predetermined maximum loss in the packet rate of the primary link. In achieving this objective, we develop an algorithm that selects the best antenna, which maintains the quality of the secondary link in terms of signal-to-noise ratio above a specific threshold, based on overhearing the acknowledgment (ACK) and negative acknowledgment (NACK) feedback messages transmitted over the primary link. We also develop closed form expressions for the bit error rates and the effective throughput of the secondary link. © 2011 IEEE.

  11. An Ontology Based Methodology for Satellite Data Semantic Interoperability

    Directory of Open Access Journals (Sweden)

    ABBURU, S.

    2015-08-01

    Full Text Available Satellites and ocean based observing system consists of various sensors and configurations. These observing systems transmit data in heterogeneous file formats and heterogeneous vocabulary from various data centers. These data centers maintain a centralized data management system that disseminates the observations to various research communities. Currently, different data naming conventions are being used by existing observing systems, thus leading to semantic heterogeneity. In this work, sensor data interoperability and semantics of the data are being addressed through ontologies. The present work provides an effective technical solution to address semantic heterogeneity through semantic technologies. These technologies provide interoperability, capability to build knowledge base, and framework for semantic information retrieval by developing an effective concept vocabulary through domain ontologies. The paper aims at a new methodology to interlink the multidisciplinary and heterogeneous sensor data products. A four phase methodology has been implemented to address satellite data semantic interoperability. The paper concludes with the evaluation of the methodology by linking and interfacing multiple ontologies to arrive at ontology vocabulary for sensor observations. Data from Indian Meteorological satellite INSAT-3D satellite have been used as a typical example to illustrate the concepts. This work on similar lines can also be extended to other sensor observations.

  12. Estimating Transmitted-Signal Phase Variations for Uplink Array Antennas

    Science.gov (United States)

    Paal, Leslie; Mukai, Ryan; Vilntrotter, Victor; Cornish, Timothy; Lee, Dennis

    2009-01-01

    A method of estimating phase drifts of microwave signals distributed to, and transmitted by, antennas in an array involves the use of the signals themselves as phase references. The method was conceived as part of the solution of the problem of maintaining precise phase calibration required for proper operation of an array of Deep Space Network (DSN) antennas on Earth used for communicating with distant spacecraft at frequencies between 7 and 8 GHz. The method could also be applied to purely terrestrial phased-array radar and other radio antenna array systems. In the DSN application, the electrical lengths (effective signal-propagation path lengths) of the various branches of the system for distributing the transmitted signals to the antennas are not precisely known, and they vary with time. The variations are attributable mostly to thermal expansion and contraction of fiber-optic and electrical signal cables and to a variety of causes associated with aging of signal-handling components. The variations are large enough to introduce large phase drifts at the signal frequency. It is necessary to measure and correct for these phase drifts in order to maintain phase calibration of the antennas. A prior method of measuring phase drifts involves the use of reference-frequency signals separate from the transmitted signals. A major impediment to accurate measurement of phase drifts over time by the prior method is the fact that although DSN reference-frequency sources separate from the transmitting signal sources are stable and accurate enough for most DSN purposes, they are not stable enough for use in maintaining phase calibrations, as required, to within a few degrees over times as long as days or possibly even weeks. By eliminating reliance on the reference-frequency subsystem, the present method overcomes this impediment. In a DSN array to which the present method applies (see figure), the microwave signals to be transmitted are generated by exciters in a signal

  13. Evaluation of compressed digital high-definition video transmitted through the NASA communications system

    Science.gov (United States)

    Beakley, Guy W.; Kohn, Elliott S.

    1993-01-01

    A series of experiments was conducted over the past three years to prepare NASA for the use of high-definition television. In 1989 and in 1990, HDTV technology was evaluated for potential use in launch operations, real-time image analysis, and media dissemination at the Kennedy Space Center (KSC). Evaluation of camera and lens performance is reported here. In November 1991, an experiment was done at the Johnson Space Center (JSC) to evaluate the quality of HDTV that was digitized, compressed to a 45 Mbps data stream, and transmitted through the NASA communications network. The JSC experiment consisted of back-to-back bench tests of the Alcatel/Telettra high-definition coder/decoder (codec), followed by data transmission through the NASA Shuttle communications simulator, and most importantly, actual transmission through the NASA Tracking and Data Relay Satellite System (TDRSS), with a second satellite hop through a domestic satellite and a fiber-optic link at JSC. Static and dynamic test signals were used to test codec performance as were various types of subjective- test scenes with detail and motion. Included in the subjective material was IMAX film shot in space and transferred directly to high-definition video at 30 frames/second. Static tests highlighted the effects of the 54 MHz sampling rate in the codec. Color reproduction tests showed very little color error, even when transcoding externally from GBR signals. Dynamic test signals characterized the DCT and motion-compensation algorithm. Frame-by-frame analysis showed a small reduction in horizontal resolution, small color errors in fine detail, and reduced horizontal and vertical resolution immediately following transitions, where the effect was almost entirely masked by the transitions. Subjective codec performance on moving images at nominal TDRSS bit-error-rates (BER) was extremely good. The codec designers have done a very good job of leaving out information that is not perceived while including almost

  14. Satellite Upper Air Network (SUAN)

    Science.gov (United States)

    Reale, Tony L.; Thorne, Peter

    2004-10-01

    During the past 20 years of NOAA operational polar satellites, it has become evident that a growing problem concerning their utilization in Climate and also Numerical Weather Prediction (NWP) applications are the systematic errors and uncertainties inherent in the satellite measurements. Similar arguments can be made for global radiosonde observations. These uncertainties are often larger than the sensitive signals and processes, that satellite and radiosonde measurements are designed to reveal, particularly in the realm of climate. Possible strategies to quantify and compensate for these problems include the analysis of satellite overlap data and/or available collocations of satellite and ground truth (radiosonde) observations. However, overlap observations are typically not available except in extreme polar regions and current sampling strategies for compiling collocated radiosonde and satellite observations are insufficient, further compounding the inherent uncertainties in the ground-truth radiosonde data. A Satellite Upper Air Network is proposed to provide reference radiosonde launches coincident with operational polar satellite(s) overpass. The SUAN consist of 36 global radiosonde stations sub-sampled from the Global Upper Air Network (GUAN), and is designed to provide a robust, global sample of collocated radiosonde and satellite observations conducive to the monitoring and validation of satellite and radiosonde observations. The routine operation of such a network in conjunction with operational polar satellites would provide a long-term of performance for critical observations of particular importance for climate. The following report presents a candidate network of 36 upper-air sites that could comprise a SUAN. Their selection along with the mutual benefit across the satellite, radiosonde, climate, numerical weather prediction (NWP) and radiative transfer (RT) model areas are discussed.

  15. Diversity reception for advanced multi-satellite networks: A CDMA approach

    Science.gov (United States)

    Colzi, E.; Degaudenzi, R.; Elia, C.; Giannetti, F.; Viola, R.

    1993-01-01

    Diversity reception for Synchronous CDMA (S-CDMA) is introduced and analyzed. A Gaussian co-channel synchronous and asynchronous interference approximation is derived to evaluate the effects on the system bit error rate. Numerical results are provided for a simple mobile communication system where the signals transmitted by two distinct satellites in visibility are coherently combined by a three fingers Rake receiver. A second example showing performance of an integrated ground/satellite single frequency network for digital audio broadcasting is presented. Results show the capacity advantage of utilizing S-CDMA in combination with diversity reception.

  16. Leo Satellite Communication through a LEO Constellation using TCP/IP Over ATM

    Science.gov (United States)

    Foore, Lawrence R.; Konangi, Vijay K.; Wallett, Thomas M.

    1999-01-01

    The simulated performance characteristics for communication between a terrestrial client and a Low Earth Orbit (LEO) satellite server are presented. The client and server nodes consist of a Transmission Control Protocol /Internet Protocol (TCP/IP) over ATM configuration. The ATM cells from the client or the server are transmitted to a gateway, packaged with some header information and transferred to a commercial LEO satellite constellation. These cells are then routed through the constellation to a gateway on the globe that allows the client/server communication to take place. Unspecified Bit Rate (UBR) is specified as the quality of service (QoS). Various data rates are considered.

  17. Analysis of coherent satellite communication systems in the presence of interference and noise

    Science.gov (United States)

    Huang, T.-C.; Omura, J. K.; Lindsey, W. C.

    1981-01-01

    The general analysis presented can be used to evaluate the performance of M-ary phase shift keying (MPSK) used over a nonlinear satellite channel in the presence of interference (CW tone and ISI) and channel noise. The numerical evaluation is based on the classical moment technique for approximating the probability distribution from moments of a random variable. The mathematical formulation of error probabilities of MPSK signals transmitted over nonlinear satellite repeaters is presented to include the effect of CW tone interference as well as the intersymbol interference. The approach is general and can be extended to include the effect of the synchronization.

  18. Diversity reception for advanced multi-satellite networks: A CDMA approach

    Science.gov (United States)

    Colzi, E.; Degaudenzi, R.; Elia, C.; Giannetti, F.; Viola, R.

    Diversity reception for Synchronous CDMA (S-CDMA) is introduced and analyzed. A Gaussian co-channel synchronous and asynchronous interference approximation is derived to evaluate the effects on the system bit error rate. Numerical results are provided for a simple mobile communication system where the signals transmitted by two distinct satellites in visibility are coherently combined by a three fingers Rake receiver. A second example showing performance of an integrated ground/satellite single frequency network for digital audio broadcasting is presented. Results show the capacity advantage of utilizing S-CDMA in combination with diversity reception.

  19. Radio broadcasting via satellite

    Science.gov (United States)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  20. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  1. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  2. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  3. The Galilean Satellites

    Science.gov (United States)

    1998-01-01

    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft acquired the Io and Ganymede images in June 1996, the Europa images in September 1996, and the Callisto images in November 1997.Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission

  4. Future communications satellite applications

    Science.gov (United States)

    Bagwell, James W.

    1992-01-01

    The point of view of the research is made through the use of viewgraphs. It is suggested that future communications satellite applications will be made through switched point to point narrowband communications. Some characteristics of which are as follows: small/low cost terminals; single hop communications; voice compatible; full mesh networking; ISDN compatible; and possible limited use of full motion video. Some target applications are as follows: voice/data networks between plants and offices in a corporation; data base networking for commercial and science users; and cellular radio internodal voice/data networking.

  5. HETE Satellite Power Subsystem

    OpenAIRE

    1993-01-01

    The HETE (High-Energy Transient Experiment) satellite a joint project between MIT's Center for Space Research and AeroAstro. is a high-energy gamma-ray burst/X-Ray/UV observatory platform. HETE will be launched into a 550 km circular orbit with an inclination of 37.7°, and has a design lifetime of 18 months. This paper presents a description of the spacecraft's power subsystem, which collects, regulates, and distributes power to the experiment payload modules and to the various spacecraft sub...

  6. Choice of antenna geometry for microwave power transmission from solar power satellites

    Science.gov (United States)

    Potter, Seth D.

    1992-01-01

    A comparison is made between square and circular transmitting antennas for solar power satellite microwave power transmission. It is seen that the exclusion zone around the rectenna needed to protect populations from microwaves is smaller for a circular antenna operating at 2.45 GHz than it is for a square antenna at that frequency. If the frequency is increased, the exclusion zone size remains the same for a square antenna, but becomes even smaller for a circular antenna. Peak beam intensity is the same for both antennas if the frequency and antenna area are equal. The circular antenna puts a somewhat greater amount of power in the main lobe and somewhat less in the side lobes. Since rain attenuation and atmospheric heating remain problems above 10 GHz, it is recommended that future solar power satellite work concentrate on circular transmitting antennas at frequencies of roughly 10 GHz.

  7. Design of a 10-Gb/s satellite downlink at millimeter-wave frequencies

    Science.gov (United States)

    Ridgway, Richard W.; Nippa, David W.; Yen, Stephen; Barnum, Thomas J.

    2011-03-01

    System requirements, including carrier frequency, transmitted power and antenna gain are presented for a 10 Gb/s satellite downlink operating at millimeter-wave frequencies. Telecommunications-grade optical components and a high-speed photodiode are used to generate and modulate millimeter-wave carrier frequencies between 90 GHz and 100 GHz at data rates in excess of 10 Gb/s. Experimental results are presented that determine the minimum received power level needed for error-free wireless data transmission. Commercially available W-band power amplifiers are shown to increase the transmitted power level and extend the error-free propagation distance to distances of 10 km. Experimental results and documented atmospheric attenuation values for clouds, fog and rain are used to estimate link budgets for a wireless downlink located on a low-earth-orbiting satellite operating at an altitude of 350 km.

  8. Massive information sharing among global data centers based on satellite laser communication

    Science.gov (United States)

    Yi, Longteng; Li, Cong; Liu, Naijin

    2015-10-01

    With the development of big data and information globalization, the requirements of massive information transmitting and sharing among data centers are expanding, especially among those data centers which are extremely far away from each other. In the above field, conventional optical fiber transmission faces many problems such as complex networking, poor security, long node switching delay, high lease and maintain cost and low migration flexibility. Besides, in the near future, data centers may tend to be built in the remote Polar Regions or on the sea for natural cooling. For the above situation, sharing the massive information among global data centers based on satellite laser communication is proposed in this paper. This proposal includes advantage analysis, research of restraining atmosphere interference, etc. At last, by comparison with conventional technology, the research result shows that massive information transmitting and sharing among global data centers based on satellite laser communication has far reaching application potential.

  9. The TAOS/STEP Satellite

    OpenAIRE

    Edwards, David; Hosken, Robert

    1995-01-01

    The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous N...

  10. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  11. Trends in mobile satellite communication

    Science.gov (United States)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  12. Magnetic Satellite Missions and Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Kotsiaros, Stavros

    2011-01-01

    Although the first satellite observations of the Earth’s magnetic field were already taken more than 50 years ago, continuous geomagnetic measurements from space are only available since 1999. The unprecedented time-space coverage of this recent data set opened revolutionary new possibilities...... for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...... exploration of Earth’s magnetic field with satellites....

  13. Satellite Communications: The Indian Scenario

    Directory of Open Access Journals (Sweden)

    Dr. Ranjit Singh

    2014-05-01

    Full Text Available India has launched as many as 73 Indian satellites as of today since its first attempt in 1975. Besides serving traditional markets of telephony and broadcasting, satellites are on the frontiers of advanced applications as telemedicine, distance learning, environment monitoring, remote sensing, and so on. Satellite systems are optimized for services such as Internet access, virtual private networks and personal access. Costs have been coming down in recent years to the point where satellite broadband is becoming competitive. This article is an attempt to view this important topic from Indian perspective. India’s Project GAGAN, GPS Aided Geo Augmented Navigation is discussed.

  14. Business Use of Satellite Communications.

    Science.gov (United States)

    Edelson, Burton I.; Cooper, Robert S.

    1982-01-01

    Reviews business communications development and discusses business applications of satellite communications, system technology, and prospects for future developments in digital transmission systems. (JN)

  15. Height, zinc and soil-transmitted helminth infections in schoolchildren

    DEFF Research Database (Denmark)

    de Gier, Brechje; Mpabanzi, Liliane; Vereecken, Kim;

    2015-01-01

    Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data...... on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris...

  16. Removing correlations in signals transmitted over a quantum memory channel

    Science.gov (United States)

    Lupo, Cosmo; Memarzadeh, Laleh; Mancini, Stefano

    2012-01-01

    We consider a model of a bosonic memory channel, which induces correlations among the transmitted signals. The application of suitable unitary transformations at the encoding and decoding stages allows the complete removal of correlations, thereby mapping the memory channel into a memoryless one. However, such transformations, being global over an arbitrarily large number of bosonic modes, are not realistically implementable. We then introduce a family of efficiently realizable transformations, which can be used to partially remove correlations among errors, and we quantify the reduction of the gap with memoryless channels.

  17. Removing correlations in signals transmitted over a quantum memory channel

    CERN Document Server

    Lupo, Cosmo; Mancini, Stefano

    2011-01-01

    We consider a model of bosonic memory channel, which induces correlations among the transmitted signals. The application of suitable unitary transformations at encoding and decoding stages allows the complete removal of correlations, mapping the memory channel into a memoryless one. However, such transformations, being global over an arbitrary large number of bosonic modes, are not realistically implementable. We then introduce a family of efficiently realizable transformations which can be used to partially remove correlations among errors, and we quantify the reduction of the gap with memoryless channels.

  18. Sexually transmitted diseases and HIV. A female perspective.

    LENUS (Irish Health Repository)

    Horgan, M

    2012-02-03

    Sexually transmitted diseases have the greatest impact on the health of women. They are frequently asymptomatic, so screening for infection is important in preventing the long-term sequelae which include infertility, ectopic pregnancy, and chronic pelvic pain. HIV continues to increase in the female population and the gynecologic complications associated with it are unique to this population. Use of zidovudine in pregnant HIV-infected women has substantially decreased the rate of vertical transmission of HIV infection. The epidemiologic synergy between HIV and STDs is well recognized and prevention of one is dependent on prevention of the other.

  19. Cardiac In-vivo Measurements Using Synthetic Transmit Aperture Ultrasound

    DEFF Research Database (Denmark)

    Andresen, Henrik; Nikolov, Svetoslav; Hassager, Christian

    2006-01-01

    This paper investigates the feasibility of acquiring cardiac images using synthetic transmit aperture (STA) ultrasound. Focusing in STA is done by beamforming all points in the image for every emission, creating a low-resolution image. The low-resolution images for each emission are summed......, together with the RASMUS experimental ultrasound scanner. Both transducers have a pitch of half a wavelength. To ensure an adequate signal-to-noise ratio, a 20 mus non-linear frequency modulated chirp and a 7-element de-focused virtual source were used for transmission. The number of virtual sources used...

  20. Adaptive Receive and Transmit Apodization for Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Holfort, Iben Kraglund; Austeng, Andreas; Synnevåg, Johan-Fredrik

    2009-01-01

    This paper suggests a framework for utilizing adaptive, data-dependent apodization weights on both the receiving and transmitting aperture for Synthetic Aperture (SA) ultrasound imaging. The suggested approach is based on the Minimum Variance (MV) beamformer and consists of two steps. A set...... emission images before summation. The method is investigated using simulated SA ultrasound data obtained using Field II. Data of 13 point targets distributed at depths from 40 mm to 70 mm, and a 5.5 MHz, 64-element linear array transducer have been used. The investigation has shown that the introduction...

  1. Sexually transmitted diseases: reflections on metaphors and ethics.

    Science.gov (United States)

    Badura-Lotter, Gisela

    2012-01-01

    Sexually transmitted diseases (STDs) are probably the most tabooed diseases we know. The taboos and the related stigmata shape patients reality and influence significantly health care policies, medical research, and actual problems in medical ethics. To better understand these complex influences of ancient but still powerful taboos, related metaphors associated with illness and disease are analyzed according to their historical development and actual impact on society. It becomes obvious that research and health care policies cannot be satisfyingly successful in helping people affected by STDs as long as they do not take the mechanisms of taboos and associated metaphors into account.

  2. Quantitative Estimation of Transmitted and Reflected Lamb Waves at Discontinuity

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyung Jin; Sohn, Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2010-08-15

    For the application of Lamb wave to structural health monitoring(SHM), understanding its physical characteristic and interaction between Lamb wave and defect of the host structure is an important issue. In this study, reflected, transmitted and mode converted Lamb waves at discontinuity of a plate structure were simulated and the amplitude ratios are calculated theoretically using Modal decomposition method. The predicted results were verified comparing with finite element method(FEM) and experimental results simulating attached PZTs. The result shows that the theoretical prediction is close to the FEM and the experimental verification. Moreover, quantitative estimation method was suggested using amplitude ratio of Lamb wave at discontinuity

  3. Application of transmit diversity for improved robust watermarking

    Institute of Scientific and Technical Information of China (English)

    孙锐; 孙洪; 姚天任

    2004-01-01

    Many common multimedia signal processing, including cropping, filtering, and perceptual coding, make watermark signal fading-like modification. A scheme that applies transmit diversity technique to improve robustness of digital watermarking is presented. First, the scheme decomposes the original image using wavelet pyramid algorithm and chooses the middle-frequency band for transmission channel that the watermark will be embedded into. Then the watermark is pseudo-randomly permuted. The scheme makes use of space-time coding and differential detection technique to embed and extract watermark. The extracting process has access to neither the original image nor channel state information. Experimental results demonstrate that the scheme improves the performance of robust watermarking.

  4. Height, zinc and soil-transmitted helminth infections in schoolchildren

    DEFF Research Database (Denmark)

    de Gier, Brechje; Mpabanzi, Liliane; Vereecken, Kim

    2015-01-01

    Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data...... on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris...

  5. Ray-map migration of transmitted surface waves

    KAUST Repository

    Li, Jing

    2016-08-25

    Near-surface normal faults can sometimes separate two distinct zones of velocity heterogeneity, where the medium on one side of the fault has a faster velocity than on the other side. Therefore, the slope of surface-wave arrivals in a common-shot gather should abruptly change near the surface projection of the fault. We present ray-map imaging method that migrates transmitted surface waves to the fault plane, and therefore it roughly estimates the orientation, depth, and location of the near-surface fault. The main benefits of this method are that it is computationally inexpensive and robust in the presence of noise.

  6. Unconditionally secure bit commitment by transmitting measurement outcomes.

    Science.gov (United States)

    Kent, Adrian

    2012-09-28

    We propose a new unconditionally secure bit commitment scheme based on Minkowski causality and the properties of quantum information. The receiving party sends a number of randomly chosen Bennett-Brassard 1984 (BB84) qubits to the committer at a given point in space-time. The committer carries out measurements in one of the two BB84 bases, depending on the committed bit value, and transmits the outcomes securely at (or near) light speed in opposite directions to remote agents. These agents unveil the bit by returning the outcomes to adjacent agents of the receiver. The protocol's security relies only on simple properties of quantum information and the impossibility of superluminal signalling.

  7. Mitochondrial filaments and clusters as intracellular power-transmitting cables.

    Science.gov (United States)

    Skulachev, V P

    2001-01-01

    Mitochondria exist in two interconverting forms; as small isolated particles, and as extended filaments, networks or clusters connected with intermitochondrial junctions. Extended mitochondria can represent electrically united systems, which can facilitate energy delivery from the cell periphery to the cell core and organize antioxidant defence of the cell interior when O2 is consumed by mitochondrial clusters near the the outer cell membrane, and protonic potential is transmitted to the cell core mitochondria to form ATP. As to small mitochondria, they might represent a transportable form of these organelles.

  8. Unconditionally Secure Bit Commitment by Transmitting Measurement Outcomes

    CERN Document Server

    ,

    2011-01-01

    We propose a new unconditionally secure bit commitment scheme based on Minkowski causality and the properties of quantum information. The receiving party sends a number of randomly chosen BB84 qubits to the committer at a given point in space-time. The committer carries out measurements in one of the two BB84 bases, depending on the committed bit value, and transmits the outcomes securely at light speed in opposite directions to remote agents. These agents unveil the bit by returning the outcomes to adjacent agents of the receiver. The security proofs rely only on simple properties of quantum information and the impossibility of superluminal signalling.

  9. [Current protocols for diagnosis and treatment of sexually transmitted diseases].

    Science.gov (United States)

    Di Carlo, A

    2000-01-01

    This report presents the guidelines for the treatment of individuals with sexually transmitted diseases (STD) that were developed by the STD Study Group "GIRVE" of the Società Italiana di Dermatologia e Venereologia (Italian Society of Dermatology and Venerology) in accordance with those developed by the US Centers for Disease Control and Prevention in 1998. The guidelines represent a useful tool for physicians and other health-care providers in preventing and controlling STDs. The guidelines include new recommendations for treating genital herpes and genital warts.

  10. Multielement Synthetic Transmit Aperture Imaging Using Temporal Encoding

    DEFF Research Database (Denmark)

    Gammelmark, Kim; Jensen, Jørgen Arendt

    2003-01-01

    are performed using our experimental multichannel ultrasound scanning system, RASMUS. The designed linear FM signal obtains temporal sidelobes below -55 dB, and SNR investigations show improvements of 4-12 dB. A 30 turn (approximate to45%) increase in penetration depth is obtained on a multitarget phantom......A new method to increase the signal-to-noise ratio (SNR) of synthetic transmit aperture imaging is investigated. The approach utilizes multiple elements to emulate a spherical wave, and the conventional short excitation pulse is replaced by a linear frequency-modulated (FM) signal. The approach...

  11. Declassified Intelligence Satellite Photographs

    Science.gov (United States)

    ,

    2008-01-01

    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth’s land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive.The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  12. Performances of regenerative and non-regenerative satellite repeaters with MPSK signalling

    Science.gov (United States)

    Woo, K. T.

    1978-01-01

    Linear (translation), hard-limited, and demod/remod types of satellite repeaters are considered in this paper. Both uncoded and coded multiple phase shift keyed (MPSK) signals are assumed to be transmitted through these repeaters. Relative performances of these repeaters in the presence of uplink and downlink noises are then compared quantitatively. Probabilities of bit errors and the computational cutoff rates are computed for 2, 4, and 8 phases PSK signals, with uplink and downlink SNRs as parameters.

  13. Characterization of non-coding DNA satellites associated with sweepoviruses (genus Begomovirus, Geminiviridae - definition of a distinct class of begomovirus-associated satellites

    Directory of Open Access Journals (Sweden)

    Gloria eLozano

    2016-02-01

    Full Text Available Begomoviruses (family Geminiviridae are whitefly-transmitted, plant-infecting single-stranded DNA viruses that cause crop losses throughout the warmer parts of the World. Sweepoviruses are a phylogenetically distinct group of begomoviruses that infect plants of the family Convolvulaceae, including sweet potato (Ipomoea batatas. Two classes of subviral molecules are often associated with begomoviruses, particularly in the Old World; the betasatellites and the alphasatellites. An analysis of sweet potato and Ipomoea indica samples from Spain and Merremia dissecta samples from Venezuela identified small non-coding subviral molecules in association with several distinct sweepoviruses. The sequences of 18 clones were obtained and found to be structurally similar to tomato leaf curl virus–satellite (ToLCV-sat, the first DNA satellite identified in association with a begomovirus, with a region with significant sequence identity to the conserved region of betasatellites, an A-rich sequence, a predicted stem-loop structure containing the nonanucleotide TAATATTAC, and a second predicted stem-loop. These sweepovirus-associated satellites join an increasing number of ToLCV-sat-like non-coding satellites identified recently. Although sharing some features with betasatellites, evidence is provided to suggest that the ToLCV-sat-like satellites are distinct from betasatellites and should be considered a separate class of satellites, for which the collective name deltasatellites is proposed.

  14. Inter-satellite links for satellite autonomous integrity monitoring

    Science.gov (United States)

    Rodríguez-Pérez, Irma; García-Serrano, Cristina; Catalán Catalán, Carlos; García, Alvaro Mozo; Tavella, Patrizia; Galleani, Lorenzo; Amarillo, Francisco

    2011-01-01

    A new integrity monitoring mechanisms to be implemented on-board on a GNSS taking advantage of inter-satellite links has been introduced. This is based on accurate range and Doppler measurements not affected neither by atmospheric delays nor ground local degradation (multipath and interference). By a linear combination of the Inter-Satellite Links Observables, appropriate observables for both satellite orbits and clock monitoring are obtained and by the proposed algorithms it is possible to reduce the time-to-alarm and the probability of undetected satellite anomalies.Several test cases have been run to assess the performances of the new orbit and clock monitoring algorithms in front of a complete scenario (satellite-to-satellite and satellite-to-ground links) and in a satellite-only scenario. The results of this experimentation campaign demonstrate that the Orbit Monitoring Algorithm is able to detect orbital feared events when the position error at the worst user location is still under acceptable limits. For instance, an unplanned manoeuvre in the along-track direction is detected (with a probability of false alarm equals to 5 × 10-9) when the position error at the worst user location is 18 cm. The experimentation also reveals that the clock monitoring algorithm is able to detect phase jumps, frequency jumps and instability degradation on the clocks but the latency of detection as well as the detection performances strongly depends on the noise added by the clock measurement system.

  15. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    Science.gov (United States)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  16. Simultaneous Transmit and Receive Performance of an 8-Channel Digital Phased Array

    Science.gov (United States)

    2017-01-16

    Receive (STAR) could provide significant benefits for many applications including communications, radar, spectral sens- ing, and multifunctional...shown in Fig . 1. Transmit digital beamforming is used to reduce the total coupled power at each receive element, allowing the receive array to maintain...Canceller Receive Digital Beamfomer Isolated Receive SignalTransmit Signal ALSTAR Transmit Elements ALSTAR Receive Elements ... ... Fig . 1

  17. Begomovirus-Associated Satellite DNA Diversity Captured Through Vector-Enabled Metagenomic (VEM Surveys Using Whiteflies (Aleyrodidae

    Directory of Open Access Journals (Sweden)

    Karyna Rosario

    2016-02-01

    Full Text Available Monopartite begomoviruses (Geminiviridae, which are whitefly-transmitted single-stranded DNA viruses known for causing devastating crop diseases, are often associated with satellite DNAs. Since begomovirus acquisition or exchange of satellite DNAs may lead to adaptation to new plant hosts and emergence of new disease complexes, it is important to investigate the diversity and distribution of these molecules. This study reports begomovirus-associated satellite DNAs identified during a vector-enabled metagenomic (VEM survey of begomoviruses using whiteflies collected in various locations (California (USA, Guatemala, Israel, Puerto Rico, and Spain. Protein-encoding satellite DNAs, including alphasatellites and betasatellites, were identified in Israel, Puerto Rico, and Guatemala. Novel alphasatellites were detected in samples from Guatemala and Puerto Rico, resulting in the description of a phylogenetic clade (DNA-3-type alphasatellites dominated by New World sequences. In addition, a diversity of small (~640–750 nucleotides satellite DNAs similar to satellites associated with begomoviruses infecting Ipomoea spp. were detected in Puerto Rico and Spain. A third class of satellite molecules, named gammasatellites, is proposed to encompass the increasing number of reported small (<1 kilobase, non-coding begomovirus-associated satellite DNAs. This VEM-based survey indicates that, although recently recovered begomovirus genomes are variations of known genetic themes, satellite DNAs hold unexplored genetic diversity.

  18. General aspects concerning strictly meat and fish transmitted parasitic infections

    Directory of Open Access Journals (Sweden)

    Daniele Crotti

    2012-03-01

    Full Text Available All helminths parasitosis transmitted to humans trough ingestion of infested fleshes, where man is definitive host too, are represented by four groups of helminths: the cestodes Dyphyllobothrium spp and Spirometra spp. (Sparganum proliferum is the name of the immature plerocercoid larva, the trematodes Opisthorchis Clonorchis “group” (many could be the genera and species involved, and the nematode Capillaria philippinensis. So, for fishes humans foods (fresh or salted water the control and prevention in veterinary health must be directed to investigation regarding intermediate stages of these parasites in fishes for human alimentation; if present, they must be eliminated. The helminths parasitosis transmitted to humans trough ingestion of infected mammals meats, are represented by taeniasis (Taenia saginata, T. solium and T. saginata asiatica, where man id definitive host and the infection is caused by ingestion of bovine or swine meat, containing larvae of these cestodes, and by trichinellosis, where humans represent a intermediate stage, and the eventual pathology is caused as by adult (acute infection as by larvae (chronic infection of this nematode: usually the meats responsible are infected pork, wild pork or horse (Trichinella spp. Is inside the meats of these animals. So the veterinary control and prophylaxis are necessary to avoid this disease and preventing the infection that could be severe.

  19. Indigenous Healers’ beliefs and practices concerning sexually transmitted diseases

    Directory of Open Access Journals (Sweden)

    FM Mulaudzi

    2006-09-01

    Full Text Available A Grounded Theory study has been used, based on its Theory of Symbolic Interactionism, to explore indigenous healers’ beliefs and practices concerning sexually transmitted diseases amongst the Vhavenda. Initial data collection has been done, using purposive sampling and when categories started emerging, theoretical sampling was then used. Data were analysed by using three basic types of coding namely, open coding, axial coding and selective coding. The findings of the study revealed a variety of terms used to identify STDs. It then also became evident that there are similarities between gonorrhoea, syphilis and condylomata as shown in the orthodox Sexually transmitted diseases posters used in orthodox medicine with some of the STDs that the indigenous healers are familiar with. In accordance with the Grounded Theory, the description of types of diseases, disease patterns as well as signs and symptoms culminated in the emergence of the Dirt Theory. Based on the above findings, it was recommended that guidelines for designing a module for teaching health professionals be formulated to assist nurses in understanding the beliefs and practices of the people they serve.

  20. Home Screening for Bacterial Vaginosis to Prevent Sexually Transmitted Diseases.

    Science.gov (United States)

    Schwebke, Jane R; Lee, Jeannette Y; Lensing, Shelly; Philip, Susan S; Wiesenfeld, Harold C; Seña, Arlene C; Trainor, Nikole; Acevado, Nincoshka; Saylor, Lisa; Rompalo, Ann M; Cook, Robert L

    2016-03-01

    Longitudinal studies have consistently found a significant association between bacterial vaginosis (BV) and acquisition of sexually transmitted diseases. However, there are limited prospective data to confirm these findings. We conducted a prospective, randomized, open-label trial of home screening and treatment of young women with asymptomatic BV who were also at high risk for sexually transmitted diseases. These women were screened every 2 months for 12 months and randomized to treatment with oral metronidazole 500 mg twice daily for 7 days or observation alone. The primary outcome was the incidence of gonorrhea and/or chlamydia. A total of 1365 subjects were enrolled in the study across 10 sites. Adherence with mailing specimens obtained at home was excellent in both groups (84%-88%). The incidence of gonorrhea and/or chlamydia was 19.1 per 100 person-years (95% confidence interval, 15.1-22.1) for the treatment group and 18.5 per 100 person-years (15.1-22.8) for the observation arm, a difference that was not statistically significant. Young women were very amenable to home screening for BV, gonorrhea, and chlamydia. Treatment of asymptomatic BV with 1 week of oral metronidazole did not decrease the incidence of gonorrhea and/or chlamydia. NCT00667368. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  1. Link Scheduling in Multi-Transmit-Receive Wireless Networks

    CERN Document Server

    Dai, Hong-Ning; Fu, Liqun

    2011-01-01

    This paper investigates the problem of link scheduling to meet traffic demands with minimum airtime in a multi-transmit-receive (MTR) wireless network. MTR networks are a new class of networks, in which each node can simultaneously transmit to a number of other nodes, or simultaneously receive from a number of other nodes. The MTR capability can be enabled by the use of multiple directional antennas or multiple channels. Potentially, MTR can boost the network capacity significantly. However, link scheduling that makes full use of the MTR capability must be in place before this can happen. We show that optimal link scheduling can be formulated as a linear program (LP). However, the problem is NP-hard because we need to find all the maximal independent sets in a graph first. We propose two computationally efficient algorithms, called Heavy-Weight-First (HWF) and Max-Degree-First (MDF) to solve this problem. Simulation results show that both HWF and MDF can achieve superior performance in terms of runtime and op...

  2. Current status of soil-transmitted helminths in Vietnam

    DEFF Research Database (Denmark)

    van der Hoek, Wim; De, Nguyen Van; Konradsen, Flemming

    2003-01-01

    This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris (prevale......This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris...... is more evenly distributed throughout the country, but is concentrated in peri-urban and rural agricultural areas. Vegetable cultivation in which nightsoil is used as fertilizer is a risk factor for hookworm infection, especially among adult women. Helminth control programs should be targeted at school......-age children in the northern provinces. Specific interventions are needed throughout the country for women of agricultural communities that are at risk for hookworm infection. There is clearly a need for more detailed analysis of risk factors to quantify the relative contribution of climatic, environmental...

  3. [Analysis of spreading the sexually transmitted disorders in Georgia].

    Science.gov (United States)

    Chiokadze, Sh; Galdava, G; Kvlividze, O; Durglishvili, G

    2014-03-01

    According statistical data in Georgia sexually transmitted disorders represent one of the most important medical and social problems. Main causes of this are hard social and economic condition of the country, changing sexual-behavioral stereotypes, drugs and alcohol abuse, political perturbation, as well as unprecedented decrease in financing prevention programs of STD by government. The purpose of given research is statistical analysis of spread of sexually transmitted disorders in Georgia, in particular, among the people included in risk group; finding trends and in accordance with this, working out recommendations for improvement of situation in given field of medicine. Essays showed that through 2000-2012 years among STD revealed in the group of increased risk chlamidiosis was the most common. There is an objective trend of increasing the level of morbidity with chlamidiosis and trichomoniasis, however the speed of increasing morbidity with trichomoniasis probably does not correspond the reality. In the same time morbidity with gonorrhea and syphilis is decreasing, however in the result of significant decrease in STD prevention program scale data validity concerning syphilis might be doubtful. Coming out of this in the field of health care related to STD optimization of laboratory diagnostics management is essential; perfection of methods of epidemiologic control; increasing the scales of prevention programs as well as initiation of researches related to antimicrobial resistance of gonococci. Authors consider essential taking steps for optimization of management of laboratory diagnostics and perfection of methods of epidemiologic control and increasing scales of preventive programs.

  4. On Dynamic Transmitting Property of Circular Plate MR Clutch

    Science.gov (United States)

    Guo, Chongzhi; Guo, Jiangchuan; Guo, Yu; Ma, Ziyang

    This study focuses on the analysis of relationship between the current density and the torque of a circular plate Magneto-Rheological (MR) clutch. In order to get the expression of magnetic induction intensity, the Finite Element Method(FEM) is used for the magnetic analysis on the given geometry of circular plate MR clutch under different current density. With some reasonable assumptions, the discrete values of the magnetic induction intensity along some defined paths are obtained. The fitted expression of magnetic induction intensity is derived from discrete points and the analysis of these discrete data. Based on the expression and the Bingham model which is used to describe the constitutive characteristics of the MR fluids flow between two circular plates subject to an applied magnetic field induced by current density, the mathematical model to transmit the torque is established. From the model and the fit expression, the relationship of the torque and the current density is deduced. The numerical results show that the torque transferred under magnetic induction density by control current density is increased smoothly as the current density is increased except a very short time after initial start. Results also indicate that the torque can be controlled continuously by changing the current density. The analysis provides the theoretical foundation for the design of the MR clutch, and the equation of the torque provides the information by which the torque transmitted by the clutch can be manipulated accurately through adjusting the current density.

  5. Saturation of the Electric Field Transmitted to the Magnetosphere

    Science.gov (United States)

    Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James A.

    2010-01-01

    We reexamined the processes leading to saturation of the electric field, transmitted into the Earth's ionosphere from the solar wind, incorporating features of the coupled system previously ignored. We took into account that the electric field is transmitted into the ionosphere through a region of open field lines, and that the ionospheric conductivity in the polar cap and auroral zone may be different. Penetration of the electric field into the magnetosphere is linked with the generation of the Alfven wave, going out from the ionosphere into the solar wind and being coupled with the field-aligned currents at the boundary of the open field limes. The electric field of the outgoing Alfven wave reduces the original electric field and provides the saturation effect in the electric field and currents during strong geomagnetic disturbances, associated with increasing ionospheric conductivity. The electric field and field-aligned currents of this Alfven wave are dependent on the ionospheric and solar wind parameters and may significantly affect the electric field and field-aligned currents, generated in the polar ionosphere. Estimating the magnitude of the saturation effect in the electric field and field-aligned currents allows us to improve the correlation between solar wind parameters and resulting disturbances in the Earth's magnetosphere.

  6. [Changes in vertically transmitted human immunodeficiency virus infection Chile].

    Science.gov (United States)

    Chávez P, Ana; Alvarez P, Ana M; Wu H, Elba; Peña D, Anamaría; Vizueta R, Eloísa

    2007-10-01

    The identification of various risk factors of vertical human immunodeficiency virus (HIV) transmission resulted in the development of strategies whose aim was to decrease the mother's viral load, to reduce her child's exposure to it during delivery, and to avoid the subsequent viral exposure due to breastfeeding. The administration of antiretroviral treatment during pregnancy, delivery and to the neonate (PACTG 076) proved to be useful. At a first stage, zidovudine was used. A triple combination therapy was then administered. Initially, the viral transmission in mothers who were enrolled in protocols for vertically transmitted HIV prophylaxis was reduced to 9.5%, whereas the last measurement carried out between 1998 and 2005, the initial figure was brought down to 2%. Nevertheless, the delivery of infected children whose mother's HIV status was unknown is still considered likely to happen. The main step to be taken to reduce HIV infection among children is to perform universal HIV tests during pregnancy, so that HIV positive pregnant patients conveniently receive proper prophylaxis. We look forward to achieving this by following the new prevention guidelines of vertically-transmitted HIV infection, developed by the Comisión Nacional del SIDA of the Chilean Health Ministry.

  7. Modeling Endovascular MRI Coil Coupling with Transmit RF Excitation

    Science.gov (United States)

    Venkateswaran, Madhav; Unal, Orhan; Hurley, Samuel; Samsonov, Alexey; Wang, Peng; Fain, Sean; Kurpad, Krishna

    2016-01-01

    Objective To model inductive coupling of endovascular coils with transmit RF excitation for selecting coils for MRI-guided interventions. Methods Independent and computationally efficient FEM models are developed for the endovascular coil, cable, transmit excitation and imaging domain. Electromagnetic and circuit solvers are coupled to simulate net B1+ fields and induced currents and voltages. Our models are validated using the Bloch Siegert B1+ mapping sequence for a series-tuned multimode coil, capable of tracking, wireless visualization and high resolution endovascular imaging. Results Validation shows good agreement at 24, 28 and 34 μT background RF excitation within experimental limitations. Quantitative coil performance metrics agree with simulation. A parametric study demonstrates trade off in coil performance metrics when varying number of coil turns. Tracking, imaging and wireless marker multimode coil features and their integration is demonstrated in a pig study. Conclusion Developed models for the multimode coil were successfully validated. Modeling for geometric optimization and coil selection serves as a precursor to time-consuming and expensive experiments. Specific applications demonstrated include parametric optimization, coil selection for a cardiac intervention and an animal imaging experiment. Significance Our modular, adaptable and computationally efficient modeling approach enables rapid comparison, selection and optimization of inductively-coupled coils for MRI-guided interventions. PMID:26960218

  8. Use of Earth Observing Satellites for Operational Hazard Support

    Science.gov (United States)

    Wood, H. M.; Lauritson, L.

    continental U.S., Carribean, and adjacent oceans, it also tracks volcanic eruptions throughout the world. Text messages are produced along with graphic interpretations. This information, along with volcanic ash forecasts produced by NOAA's National Weather Service, is made available to U.S. Government and international agencies concerned with aviation, seismology, and climate analysis. Earth observing satellites help NESDIS to ensure safe navigation of ships through sea ice by measuring the extent, thickness, and age of ice as well as sea surface winds over the polar regions of the globe, coastal areas, and inland waterways. These satellites also help NESDIS to monitor U.S. coastal areas for dangerous algal blooms or other toxic effects to fish and sea mammals as well as monitoring floods and fires. Experimental fire products can help in the monitoring of fires and fire weather, as well as determining fire risk. Experimental soil moisture products support flood and drought monitoring. Flood extent and damage assessment for a variety of hazards can be determined from several satellites at varying spatial resolutions. The Search and Rescue Satellite Aided Tracking (SARSAT) system detects and locates persons in distress on land or water. NOAA satellites relay distress signals from emergency beacons through a network of ground stations to the U.S. Mission Control Center (USMCC). The USMCC processes the data and alerts the appropriate search and rescue authorities. SARSAT is part of the international Cospas-Sarsat Program. NOAA's GOES Data Collection (DCS) and Argos (jointly with the French space agency) POES Data Collection and Locations Systems transmit data collected from remote land and water based platforms and distributes the data to researchers, governmental and environmental organizations worldwide. The GOES DCS system allows near real time and frequent transmissions, e.g. hourly, over the Americas and much of the Atlantic and Eastern Pacific Oceans. ARGOS transmissions

  9. Multicast Routing in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    郭惠玲; 宋姝; 李磊; 刘志涛; 郭鹏程

    2004-01-01

    There are some problems in the dual-layer satellite MPLs metworks to be composed of LEO and MEO. In order to solve the problems, this paper presents a plan by means of unicast LSP to implement multicast in the dual-layer satellite MPLs networks. It has advantages of saving space and reducing extra charge.

  10. Magnetic Satellite Missions and Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Kotsiaros, Stavros

    2011-01-01

    for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...

  11. The SPOT satellite

    Science.gov (United States)

    Fouquet, J.-P.

    1981-03-01

    The background, objectives and data products of the French SPOT remote sensing satellite system are presented. The system, which was developed starting in 1978 with the subsequent participation of Sweden and Belgium, is based on a standard multimission platform with associated ground control station and a mission-specific payload, which includes two High-Resolution Visible range instruments allowing the acquisition of stereoscopic views from different orbits. Mission objectives include the definition of future remote sensing systems, the compilation of a cartographic and resources data base, the study of species discrimination and production forecasting based on frequent access and off-nadir viewing, the compilation of a stereoscopic data base, and platform and instrument qualification, for possible applications in cartography, geology and agriculture. Standard data products will be available at three levels of preprocessing: radiometric correction only, precision processing for vertical viewing, and cartographic quality processing.

  12. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements...

  13. Astronomy from satellite clusters

    Science.gov (United States)

    Stachnik, R.; Labeyrie, A.

    1984-03-01

    Attention is called to the accumulating evidence that giant space telescopes, comprising a number of separate mirrors on independent satellites, are a realistic prospect for providing research tools of extraordinary power. The ESA-sponsored group and its counterpart in the US have reached remarkably similar conclusions regarding the basic configuration of extremely large synthetic-aperture devices. Both share the basic view that a cluster of spacecraft is preferable to a single monolithic structure. The emphasis of the US group has been on a mission that sweeps across as many sources as possible in the minimum time; it is referred to as SAMSI (Spacecraft Array for Michelson Spatial Interferometry). The European group has placed more emphasis on obtaining two-dimensional images. Their system is referred to as TRIO because, at least initially, it involves three independent systems. Detailed descriptions are given of the two systems.

  14. Direct Broadcast Satellite: Radio Program

    Science.gov (United States)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  15. Sky alert! when satellites fail

    CERN Document Server

    Johnson, Les

    2013-01-01

    How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at areas where the loss could have catastrophic effects. The book - demonstrates our dependence on space technology and satellites; - outlines the effect on our economy, defense, and daily lives if satellites and orbiting spacecraft were destroyed; - illustrates the danger of dead satellites, spent rocket stages, and space debris colliding with a functioning satellites; - demonstrates the threat of dramatically increased radiation levels associated with geomagnetic storms; - introduces space as a potential area of conflict between nations.

  16. Induction studies with satellite data

    DEFF Research Database (Denmark)

    Olsen, Nils

    1999-01-01

    analysis of the geomagnetic field is performed, and the Q-response, which is the transfer function between the internal (induced) and the external (inducing) expansion coefficients is determined for a specific frequency. In the second approach, known as the geomagnetic depth sounding method, the C....... This paper reviews and discusses the possibilities for induction studies using high-precision magnetic measurements from low-altitude satellites. The different methods and various transfer functions are presented, with special emphasis on the differences in analysing data from ground stations and from...... satellites. The results of several induction studies with scalar satellite data (from the POGO satellites) and with vector data (from the Magsat mission) demonstrate the ability to probe the Earth's conductivity from space. However, compared to the results obtained with ground data the satellite results...

  17. The Communications Satellite as Educational Tool.

    Science.gov (United States)

    Long, Peter

    1982-01-01

    Drawing on the experiences of several countries, the author describes satellite technology, discusses the feasibility of satellite use in traditional educational institutions, and analyzes the role of satellites in social development. (SK)

  18. Polar-Orbiting Satellite (POES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from camera systems or radiometer instruments on satellites in orbit around the poles. Satellite campaigns include...

  19. Efficient Transmit Beamspace Design for Search-Free Based DOA Estimation in MIMO Radar

    Science.gov (United States)

    Khabbazibasmenj, Arash; Hassanien, Aboulnasr; Vorobyov, Sergiy A.; Morency, Matthew W.

    2014-03-01

    In this paper, we address the problem of transmit beamspace design for multiple-input multiple-output (MIMO) radar with colocated antennas in application to direction-of-arrival (DOA) estimation. A new method for designing the transmit beamspace matrix that enables the use of search-free DOA estimation techniques at the receiver is introduced. The essence of the proposed method is to design the transmit beamspace matrix based on minimizing the difference between a desired transmit beampattern and the actual one under the constraint of uniform power distribution across the transmit array elements. The desired transmit beampattern can be of arbitrary shape and is allowed to consist of one or more spatial sectors. The number of transmit waveforms is even but otherwise arbitrary. To allow for simple search-free DOA estimation algorithms at the receive array, the rotational invariance property is established at the transmit array by imposing a specific structure on the beamspace matrix. Semi-definite relaxation is used to transform the proposed formulation into a convex problem that can be solved efficiently. We also propose a spatial-division based design (SDD) by dividing the spatial domain into several subsectors and assigning a subset of the transmit beams to each subsector. The transmit beams associated with each subsector are designed separately. Simulation results demonstrate the improvement in the DOA estimation performance offered by using the proposed joint and SDD transmit beamspace design methods as compared to the traditional MIMO radar technique.

  20. Stereoscopic observations from meteorological satellites

    Science.gov (United States)

    Hasler, A. F.; Mack, R.; Negri, A.

    The capability of making stereoscopic observations of clouds from meteorological satellites is a new basic analysis tool with a broad spectrum of applications. Stereoscopic observations from satellites were first made using the early vidicon tube weather satellites (e.g., Ondrejka and Conover [1]). However, the only high quality meteorological stereoscopy from low orbit has been done from Apollo and Skylab, (e.g., Shenk et al. [2] and Black [3], [4]). Stereoscopy from geosynchronous satellites was proposed by Shenk [5] and Bristor and Pichel [6] in 1974 which allowed Minzner et al. [7] to demonstrate the first quantitative cloud height analysis. In 1978 Bryson [8] and desJardins [9] independently developed digital processing techniques to remap stereo images which made possible precision height measurement and spectacular display of stereograms (Hasler et al. [10], and Hasler [11]). In 1980 the Japanese Geosynchronous Satellite (GMS) and the U.S. GOES-West satellite were synchronized to obtain stereo over the central Pacific as described by Fujita and Dodge [12] and in this paper. Recently the authors have remapped images from a Low Earth Orbiter (LEO) to the coordinate system of a Geosynchronous Earth Orbiter (GEO) and obtained stereoscopic cloud height measurements which promise to have quality comparable to previous all GEO stereo. It has also been determined that the north-south imaging scan rate of some GEOs can be slowed or reversed. Therefore the feasibility of obtaining stereoscopic observations world wide from combinations of operational GEO and LEO satellites has been demonstrated. Stereoscopy from satellites has many advantages over infrared techniques for the observation of cloud structure because it depends only on basic geometric relationships. Digital remapping of GEO and LEO satellite images is imperative for precision stereo height measurement and high quality displays because of the curvature of the earth and the large angular separation of the

  1. MIMO Radar Transmit Beampattern Design for DOA Estimation with Sidelobe Suppression

    Directory of Open Access Journals (Sweden)

    Yuxiang Li

    2016-01-01

    Full Text Available We address the problem of transmit beamspace design for multiple-input multiple-output (MIMO radar with colocated antennas in direction-of-arrival (DOA estimation application. Three transmit beampattern sidelobe suppression strategies for designing the transmit beamspace matrix are introduced. The design of transmit beamspace matrix is based on minimizing the difference between a desired transmit beampattern and the actual one while keeping the sidelobe levels under control. Uniform elemental power distribution across the transmit antenna is guaranteed; at the same time, signal rotational invariance property is considered, which enables search-free based DOA estimation algorithms to be utilized at the receiver. The proposed optimization problems are nonconvex and are solved by using semidefinite programming relaxation technique. Moreover, the DOA estimation Cramer-Rao bound with transmit beamspace matrix is discussed. Simulation results show the superiority of the proposed techniques over the existing methods.

  2. Laser Experiments with ARTEMIS Satellite in Cloudy Conditions

    Science.gov (United States)

    Kuzkov, Volodymyr; Sodnik, Zoran; Kuzkov, Sergii; Caramia, Vincenzo

    2014-05-01

    In July 2001, the ARTEMIS satellite with laser communication terminal OPALE on board was launched. 1789 laser communications sessions were performed between ARTEMIS and SPOT-4 (PASTEL) from 01 April 2003 to 09 January 2008 with total duration of 378 hours. In addition ESA's Optical Ground Station (OGS) performed laser communication experiments with OPALE in various atmospheric conditions. Since the launch of ARTEMIS, the amount of information handled by geostationary telecommunication satellites has increased dramatically and so has the demand for data rate that needs to be transmitted from ground. With limited bandwidth allocations in the radio frequency bands interest has grown for laser communication feeder link technology. In this respect there is interest to compare the influence of atmosphere conditions in different atmospheric regions with respect to laser transmission. Two locations are being compared, namely ESA's OGS (located in an altitude of 2400 m above sea level) and the Main Astronomical Observatory of Ukraine (MAO) (located at an altitude of 190 m above sea level). In 2002 MAO started the development of a ground laser communication system for the AZT-2 telescope. The MAO developed compact laser communication system is called LACES (Laser Atmosphere and Communication Experiments with Satellites) [1] and the work was supported by the National Space Agency of Ukraine and by ESA. The beacon laser from OPALE was occasionally detected even in cloudy conditions and an anomalous atmospheric refraction at low elevation angles was observed. The main results of laser experiments with ARTEMIS through clouds are presented in the paper.

  3. Video Streaming Transfer in a Smart Satellite Mobile Environment

    Directory of Open Access Journals (Sweden)

    Nedo Celandroni

    2009-01-01

    satellite link for transmitting video streams to a bus, where they are relayed to passengers' devices. We say that a bus works in smart mode if it takes advantage of the knowledge of the exact points where fixed obstacles will prevent receiving the satellite signal for a certain time period. This information is sent to the hub via a return channel. The hub, in its turn, suspends the transmissions to that specific bus for the given time interval, thus avoiding information losses and unnecessary bandwidth occupation. Buffering video packets, without any quality of service (QoS degradation, seamlessly compensates channel blockages up to a given duration. We determine the most appropriate transmission parameters for video streaming with good video QoS in a mobile satellite environment; moreover, we evaluate how “smart” the system can be in terms of bandwidth saving, by comparing it with the situation where the bus does not exploit the description of its route, still maintaining the same QoS requirements.

  4. Theory of satellite geodesy applications of satellites to geodesy

    CERN Document Server

    Kaula, William M

    2000-01-01

    The main purpose of this classic text is to demonstrate how Newtonian gravitational theory and Euclidean geometry can be used and developed in the earth's environment. The second is to collect and explain some of the mathematical techniques developed for measuring the earth by satellite.Book chapters include discussions of the earth's gravitational field, with special emphasis on spherical harmonies and the potential of the ellipsoid; matrices and orbital geometry; elliptic motion, linear perturbations, resonance, and other aspects of satellite orbit dynamics; the geometry of satellite obser

  5. Olympic outreach: testing for sexually transmitted infections in construction workers.

    Science.gov (United States)

    Shanmugaratnam, S; Horne, P; Coyne, K M

    2012-09-01

    Concerns have been voiced in the national press that the surge in migrant construction workers leading up to the 2012 Olympics Games would increase the levels of sexual ill health in East London. Between 2009 and 2011, we sent a sexual health outreach team to the Olympic Park and Village. A total of 614 clients were tested, of whom 91% were men and 46% reported English/Scottish/Welsh ethnicity. The age range was 17-73 years and median age 30 years. Reported sexual risk factors were low, including use of commercial sex workers. Prevalence of sexually transmitted infections was low, with Chlamydia trachomatis found in 20 clients (3%), and hepatitis B diagnosed in one client. This study, although small, did not support the image of construction workers presenting a higher than average sexual health risk.

  6. Trichomonas vaginalis - an indicator for other sexually transmitted infecting agents

    Directory of Open Access Journals (Sweden)

    Agrawal B

    1998-01-01

    Full Text Available The present study is based on 350 women having sexually transmitted diseases and 68 men counterparts. Trichomonas vaginalis was a significant contributor in 216 (61.7% out of 350 female SID cases′ and in 56 (82.3% out of 68 male counterparts. Further, out of 216 cases of T.vaginalis, 41 cases (32.5% were associated with infection with Candida species; 29 (23% with Neisseria gonorrhoea. 18 cases (14.3% with Haemophilus ducreyi and 11 cases (8.7%, Chlamydia trachomatis. Treponema pallidum was observed in 8 cases (6.3% which constituted a low percentage. Present study highlighted the importance of T. vaginalis by showing positivity in two-third cases which suggested that it can be an important indicator for other etiological STD agents in women.

  7. Downlink scheduling of multiuser MIMO systems with transmit beamforming

    Institute of Scientific and Technical Information of China (English)

    SONG Xing-hua; WU Wei-ling

    2008-01-01

    This article deals with downlink scheduling for multiuser multiple-input multiple-output (MIMO) systems, where the base station communicates with multiple users simultaneously through transmit beamforming. Most of the existing transmission schemes for multiuser MIMO systems focus on optimizing sum rate performance of the system. The individual quality of service (QoS) requirements (such as packet delay and minimum transmission rate for the data traffic) are rarely considered. In this article, a novel scheduling strategy is proposed, where we try to optimize the global system performance under individual QoS constraints. By performing scheduling into two steps, namely successive user selection and power allocation, the scheduler can achieve efficient resource utilization while maintaining the QoS requirements of all users. Extensive simulations and analysis are given to show the effectiveness of the proposed scheduler.

  8. Stochastic spatial structured model for vertically and horizontally transmitted infection

    Science.gov (United States)

    Silva, Ana T. C.; Assis, Vladimir R. V.; Pinho, Suani T. R.; Tomé, Tânia; de Oliveira, Mário J.

    2017-02-01

    We study a space structured stochastic model for vertical and horizontal transmitted infection. By means of simple and pair mean-field approximation as well as Monte Carlo simulations, we construct the phase diagram, which displays four states: healthy (H), infected (I), extinct (E), and coexistent (C). In state H only healthy hosts are present, whereas in state I only infected hosts are present. The state E is characterized by the extinction of the hosts whereas in state C there is a coexistence of infected and healthy hosts. In addition to the usual scenario with continuous transition between the I, C and H phases, we found a different scenario with the suppression of the C phase and a discontinuous phase transition between I and H phases.

  9. MIMO Transmission with Residual Transmit-RF Impairments

    CERN Document Server

    Studer, Christoph; Burg, Andreas

    2010-01-01

    Physical transceiver implementations for multiple-input multiple-output (MIMO) wireless communication systems suffer from transmit-RF (Tx-RF) impairments. In this paper, we study the effect on channel capacity and error-rate performance of residual Tx-RF impairments that defy proper compensation. In particular, we demonstrate that such residual distortions severely degrade the performance of (near-)optimum MIMO detection algorithms. To mitigate this performance loss, we propose an efficient algorithm, which is based on an i.i.d. Gaussian model for the distortion caused by these impairments. In order to validate this model, we provide measurement results based on a 4-stream Tx-RF chain implementation for MIMO orthogonal frequency-division multiplexing (OFDM).

  10. A social model for the evolution of sexually transmitted diseases

    Science.gov (United States)

    Gonçalves, Sebastián; Kuperman, Marcelo; Ferreira da Costa Gomes, Marcelo

    2004-10-01

    We have introduced recently a model for the spread of sexually transmitted diseases, in which the social behavior is incorporated as a key factor for the further propagation of the infection. The system may be regarded as a society of agents where in principle anyone can sexually interact with any other one in the population. The social behavior is taking into account by means of two parameters: the fraction of singles ρs and the promiscuity p. The promiscuity parameter defines the per individual daily probability of going out to look for a sexual partner, abandoning its eventual mate. In this contribution we show that the interaction between this two parameters give rise to a non-trivial epidemic threshold condition, when going from the homogeneous case ( ρs=1) to heterogeneous cases ( ρs<1). These results can have profound implication in the interpretation of real epidemic data.

  11. Sexually transmitted diseases in men who have sex with men.

    Science.gov (United States)

    Mayer, Kenneth H

    2011-12-01

    Men who have sex with men (MSM) have increased rates of human immunodeficiency virus (HIV) infection and sexually transmitted diseases (STDs) compared with demographically matched controls. The reasons for the disproportionate infection burden are complex, including biological, behavioral, and sociocultural factors. HIV and syphilis may often be coprevalent among MSM. The use of nucleic acid amplification testing has enhanced the ability to detect frequently asymptomatic gonococcal and chlamydial infections of the rectum and other sites. Lymphogranuloma proctitis outbreaks among MSM were noted in the developed world several years ago but have not been common recently. MSM are at increased risk for viral hepatitis and anal human papillomavirus disease. Preventive interventions include vaccination for the former and anal cytologic screening for the latter. Because of the diverse ways in which MSM may be exposed to STDs, it is essential for clinicians to obtain a thorough sexual history in a culturally competent manner.

  12. Vulvovaginitis: promotion of condom use to prevent sexually transmitted disease.

    Science.gov (United States)

    LeVasseur, J J

    1992-09-01

    Many studies have suggested that merely warning people about the dangers of sexually transmitted diseases (STDs) and urging the use of condoms as protection will not result in widespread use of condoms. Regular condom use appears to be grounded in knowledge of its effectiveness, perception of STD risk, and belief in a partner's acceptance. But these are not the only barriers to condom use. Negotiating condom use often comes at a sensitive stage in intimate relationships, when individuals prefer to avoid such discussions and simply to trust the powerful and compelling feelings of mutual attraction. This review will consider (1) the effectiveness of condoms in preventing STD transmission, (2) barriers to the use of condoms, and (3) recommended strategies to promote acceptance and use of condoms by heterosexual women.

  13. Ferrisia gilli (Hemiptera: Pseudococcidae) Transmits Grapevine Leafroll-Associated Viruses.

    Science.gov (United States)

    Wistrom, C M; Blaisdell, G K; Wunderlich, L R; Almeida, R P P; Daane, K M

    2016-08-01

    Several mealybug species are vectors of grapevine leafroll-associated viruses (GLRaV), which cause the economically important grapevine leafroll disease in grape-producing regions worldwide. The mealybug Ferrisia gilli Gullan is a new pest of grapevines in El Dorado County, located in the Sierra Foothill wine-growing region of California. GLRaV species 1, 2, 3, and 4LV have been detected in vineyards with symptomatic vines in the Sierra Foothills. We conducted controlled virus acquisition and transmission experiments using source vine accessions infected with different combinations of GLRaV. We determined that F. gilli acquired GLRaV 1, 2, 3, and 4LV, and transmitted GLRaV-3 and GLRaV-4LV to uninfected recipient vines. Like numerous other mealybug species, in addition to causing direct damage to vines, F. gilli poses a threat to the grape industry as a vector of economically damaging viruses.

  14. Cannibalism amplifies the spread of vertically transmitted pathogens.

    Science.gov (United States)

    Sadeh, Asaf; Rosenheim, Jay A

    2016-08-01

    Cannibalism is a widespread behavior. Abundant empirical evidence demonstrates that cannibals incur a risk of contracting pathogenic infections when they consume infected conspecifics. However, current theory suggests that cannibalism generally impedes disease spread, because each victim is usually consumed by a single cannibal, such that cannibalism does not function as a spreading process. Consequently, cannibalism cannot be the only mode of transmission of most parasites. We develop simple, but general epidemiological models to analyze the interaction of cannibalism and vertical transmission. We show that cannibalism increases the prevalence of vertically transmitted pathogens whenever the host population density is not solely regulated by cannibalism. This mechanism, combined with additional, recently published, theoretical mechanisms, presents a strong case for the role of cannibalism in the spread of infectious diseases across a wide range of parasite-host systems. © 2016 by the Ecological Society of America.

  15. Identification of spinal circuits transmitting and gating mechanical pain

    Science.gov (United States)

    Bourane, Steeve; Britz, Olivier; Padilla, Christopher; Garcia-Campmany, Lidia; Krashes, Michael; Knowlton, Wendy; Velasquez, Tomoko; Ren, Xiangyu; Ross, Sarah; Lowell, Bradford B.; Wang, Yun; Goulding, Martyn; Ma, Qiufu

    2014-01-01

    SUMMARY Pain processing in the spinal cord has been postulated to rely on nociceptive transmission (T) neurons receiving inputs from nociceptors and Aβ mechanoreceptors, with Aβ inputs gated through feed-forward activation of spinal inhibitory neurons (IN). Here we used intersectional genetic manipulations to identify these critical components of pain transduction. Marking and ablating six populations of spinal excitatory and inhibitory neurons, coupled with behavioral and electrophysiological analysis, showed that excitatory neurons expressing somatostatin (SOM) represent T-type cells, whose ablation causes loss of mechanical pain. Inhibitory neurons marked by the expression of dynorphin (Dyn) represent IN-type neurons, which are necessary to gate Aβ fibers from activating SOM+ neurons to evoke pain. Therefore, peripheral mechanical nociceptors and Aβ mechanoreceptors, together with spinal SOM+ excitatory and Dyn+ inhibitory neurons form a microcircuit that transmits and gates mechanical pain. PMID:25467445

  16. A new filaria of a lizard transmitted by sandflies

    Directory of Open Access Journals (Sweden)

    Odile Bain

    1992-01-01

    Full Text Available A description is given of Madathamugadia wanjii n. sp., a Splendidofilariinae parasite of the gecko Ptyodactylus hasselquistii, on the west bank of the River Jordan and of its life cycle in Phlebotomus duboscqi. The new species is close to M. ivaschkini (Annaev, 1976 n. comb., of Turkmenistan, wich is also transmitted by sandflies (Reznik, 1982. The genus Madathamugadia is now comprised of four species, two from Madagascar and two from the Mediterranean sub-region; it differs from the genus Thamugadia by the presence of a double row of papillae anterior to the cloaca of the male. The larval characters of Splendidofilarinae of lizards confirm the affinity of these parasites to the Splendidofilarinae of birds (Chandlerella and Splendidofilaria; the first group could have arisen from the second by "captures" wich could have occurred in several places.

  17. Community understanding and prevention of sexually transmitted diseases.

    Science.gov (United States)

    Oumeish, Oumeish Youssef; Oumeish, Isam F

    2004-01-01

    In spite of the various attempts by health care workers to reduce the morbidity and mortality of sexually transmitted diseases (STDs), more than 15 million persons acquire STDs each year in the United States. The situation is more serious in developing countries and, in particular, Africa and Southeast Asia. The causes of the increase in STDs are many, but we believe that alterations in family structures, drug and alcohol addiction, wars and mobilization of armies and movement of populations, in addition to change in sexual behaviors and lax morality are the main ones. Education, counseling, and community understanding of the risks of STDs are very essential factors in prevention and control. Physicians need to recognize the manifestations of STDSs and start the treatment as early as possible, but at the same time, more efforts are needed for prevention.

  18. The Sexually Transmitted Insect Virus, Hz-2V

    Institute of Scientific and Technical Information of China (English)

    John P. Burand

    2009-01-01

    Hz-2V is one of only a very few sexually transmitted viruses currently known in insects. Replication of this insect pathogenic virus results in sterility of infected moths rather than mortality. The sterility of the infected host is a consequence of virus directed malformation of adult reproductive tissues, which in females results in cellular proliferation and hypertrophy of these tissues. Virus replication has additional ramifications in infected females. Infected females produce more mating pheromones and attract more mates than healthy females, ultimately facilitating virus transmission and enhancing viral fitness. The molecular mechanisms used by the virus to manipulate the host to enhance its fitness are yet to be determined. Unraveling the underlying principles of these mechanisms promises to enhance our understanding of insect reproductive physiology, as well as provide molecular tools for use in novel approaches in sterile insect control programs.

  19. Antenna and transceiver for transmitting a secure signal

    Science.gov (United States)

    Singleton, John; Schmidt, Andrea

    2017-08-01

    An accelerated superluminal polarization currents (ASPC) transceiver includes an ASPC transmitter including a plurality of ASPC radiator elements, the ASPC transmitter transmitting a radio signal that is focused in a target direction and scrambled in other directions; and a radio receiver, wherein the center of a pulse of the radio signal has a transit time t.sub.c from an end of the ASPC transmitter, at a first position -x.sub.0, to a second position x along the ASPC transmitter given by the following equation: t.sub.c=[R.sup.2+x.sub.0.sup.2+2Rx.sub.0 cos .psi..sub.0].sup.1/2-[R.sup.2+x.sup.2+2Rx cos .psi..sub.0].sup.1/2, where R is a target distance from the ASPC transmitter and .psi..sub.0 is a target angle and > ##EQU00001##

  20. Closed form fourier-based transmit beamforming for MIMO radar

    KAUST Repository

    Lipor, John J.

    2014-05-01

    In multiple-input multiple-output (MIMO) radar setting, it is often desirable to design correlated waveforms such that power is transmitted only to a given set of locations, a process known as beampattern design. To design desired beam-pattern, current research uses iterative algorithms, first to synthesize the waveform covariance matrix, R, then to design the actual waveforms to realize R. In contrast to this, we present a closed form method to design R that exploits discrete Fourier transform and Toeplitz matrix. The resulting covariance matrix fulfills the practical constraints and performance is similar to that of iterative methods. Next, we present a radar architecture for the desired beampattern that does not require the synthesis of covariance matrix nor the design of correlated waveforms. © 2014 IEEE.

  1. Transformer coupling for transmitting direct current through a barrier

    Science.gov (United States)

    Brown, Ralph L.; Guilford, Richard P.; Stichman, John H.

    1988-01-01

    The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level.

  2. Drug resistance in the sexually transmitted protozoan Trichomonas vaginalis

    Institute of Scientific and Technical Information of China (English)

    REBECCA L DUNNE; LINDA A DUNN; PETER UPCROFT; PETER J O'DONOGHUE; JACQUELINE A UPCROFT

    2003-01-01

    Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm delivery, low birth weight and increased infant mortality, as well as predisposing to HIV/AIDS and cervical cancer. Trichomoniasis has the highest prevalence and incidence of any sexually transmitted infection. The 5-nitroimidazole drugs, of which metronidazole is the most prescribed, are the only approved,effective drugs to treat trichomoniasis. Resistance against metronidazole is frequently reported and crossresistance among the family of 5-nitroimidazole drugs is common, leaving no alternative for treatment, with some cases remaining unresolved. The mechanism of metronidazole resistance in T. vaginalis from treatment failures is not well understood, unlike resistance which is developed in the laboratory under increasing metronidazole pressure. In the latter situation, hydrogenosomal function which is involved in activation of the prodrug, metronidazole, is down-regulated. Reversion to sensitivity is incomplete after removal of drug pressure in the highly resistant parasites while clinically resistant strains, so far analysed, maintain their resistance levels in the absence of drug pressure. Although anaerobic resistance has been regarded as a laboratory induced phenomenon, it clearly has been demonstrated in clinical isolates. Pursuit of both approaches will allow dissection of the underlying mechanisms. Many alternative drugs and treatments have been tested in vivo in cases of refractory trichomoniasis, as well as in vitro with some successes including the broad spectrum anti-parasitic drug nitazoxanide. Drug resistance incidence in T. vaginalis appears to be on the increase and improved surveillance of treatment failures is urged.

  3. Imaging parameters on third harmonic transmit phasing for tissue harmonic generation.

    Science.gov (United States)

    Shen, Che-Chou; Wang, Yu-Chun; Yeh, Chih-Kuang

    2008-06-01

    In third harmonic (3f0) transmit phasing, transmit waveforms comprising fundamental (f0) signal and 3f0 signal are used to generate both frequency-sum and frequency-difference components for manipulation of tissue harmonic amplitude. Nevertheless, the acoustic propagation of 3f0 transmit signal suffers from more severe attenuation and phase aberration than the f0 signal and hence degrades the performance of 3f0 transmit phasing. Besides, 3f0 transmit parameters such as aperture size and signal bandwidth are also influential in 3f0 transmit phasing. In this study, extensive simulations were performed to investigate the effects of these imaging parameters. Results indicate that the harmonic enhancement and suppression in 3f0 transmit phasing are compromised when the magnitude of frequency-difference component decreases in the presence of tissue attenuation and phase aberration. To compensate for the reduced frequency-difference component, a higher 3f0 transmit amplitude can be used. When the transmit parameters are concerned, a smaller 3f0 transmit aperture can provide more axially uniform harmonic enhancement and more effective suppression of harmonic amplitude. In addition, the spectral leakage signal also interferes with tissue harmonics and degrades the efficacy of 3f0 transmit phasing. Our results suggest that, in the method of 3f0 transmit phasing, the transmit amplitude, phase and aperture size of 3f0 signal should remain adjustable for optimization of clinical performance. Besides, multipulse sequences such as pulse inversion are also favorable for leakage removal in 3f0 transmit phasing.

  4. Research on handover algorithm to reduce the blocking probability in LEO satellite network

    Institute of Scientific and Technical Information of China (English)

    Chen Bingcai; Zhang Naitong; Nie Boxun; Zhou Tingxian

    2006-01-01

    Based on the characteristics of guaranteed handover (GH) algorithm, the finite capacity in one system makes the blocking probability (PB) of GH algorithm increase rapidly in the case of high traffic load. So, when large amounts of multimedia services are transmitted via a single low earth orbit (LEO) satellite system, the PB of it is much higher. In order to solve the problem, a novel handover scheme defined by multi-tier optiral layer selection is proposed. The scheme sufficienfly takes into ac count the characteristics of double-tier satellite network, which is constituted by LEO satellites combined with medium earth orbit (MEO) satellites, and the multimedia transmitted by such network, so it can augment this systematic capacity and effectively reduces the traffic load in the LEO which performs GH algorithm. The detailed processes are also presented. The simulation and numerical results show that the approach integrated with GH algorithm achieves a significant improvement in the PB and practicability, as compared to the single LEO layer network.

  5. High-Temperature Superconductive Cabling Investigated for Space Solar Power Satellites

    Science.gov (United States)

    Tew, Roy C.; Juhasz, Albert J.

    2000-01-01

    NASA has been directed by Congress to take a fresh look at the Space Solar Power (SSP) concept that was studied by the Department of Energy and NASA about 20 years ago. To summarize, the concept involves (1) collecting solar energy and converting it to electrical energy via photovoltaic arrays on satellites in Earth orbit, (2) conducting the electricity to the microwave transmitting portion of the satellite, and (3) transmitting the power via microwave transmitters (or possibly via lasers) to ground power station antennas located on the surface of the Earth. One Sun Tower SSP satellite concept is illustrated here. This figure shows many photovoltaic arrays attached to a "backbone" that conducts electricity down to a wireless transmitter, which is pointed toward the Earth. Other variations on this concept use multiple backbones to reduce the overall length of the satellite structure. In addition, non-Sun-Tower concepts are being considered. The objective of the work reported here was to determine the benefits to the SSP concept of using high-temperature superconductors (HTS) to conduct the electricity from the photovoltaic arrays to the wireless power transmitters. Possible benefits are, for example, reduced mass, improved efficiency, and improved reliability. Dr. James Powell of Plus Ultra Technologies, Inc., of Stony Brook, New York, is conducting the study, and it is being managed by the NASA Glenn Research Center at Lewis Field via a task-order contract through Scientific Applications International Corp. (SAIC).

  6. Optimization of a laser satellite communication system with an optical preamplifier.

    Science.gov (United States)

    Polishuk, Anna; Arnon, Shlomi

    2004-07-01

    We derive a model that optimizes the performance of a laser satellite communication link with an optical preamplifier in the presence of random jitter in the transmitter-receiver line of sight. The system utilizes a transceiver containing a single telescope with a circulator. The telescope is used for both transmitting and receiving and thus reduces communication terminal dimensions and weight. The optimization model was derived under the assumption that the dominant noise source was amplifier spontaneous-emission noise. It is shown that, given the required bit-error rate (BER) and the rms random pointing jitter, an optimal transceiver gain exists that minimizes transmitted power. We investigate the effect of the amplifier spontaneous-emission noise on the optimal transmitted power and gain by performing an optimization procedure for various combinations of amplifier gain and noise figure. We demonstrate that the amplifier noise figure determines the optimal transmitted power needed to achieve the desired BER but does not affect the optimal transceiver telescope gain. Our numerical example shows that for a BER of 10(-9), doubling the amplifier noise figure results in an 80% increase in minimal transmitted power for a rms pointing jitter of 0.44 microrad.

  7. Global maritime mobile service via satellite - The INMARSAT system now and in the future

    Science.gov (United States)

    Snowball, A. E.

    1986-06-01

    The business and technical aspects of the INMARSAT (International Maritime Satellite Organization) system are reviewed along with its present capabilities and services and future developments now being considered. The initial phase of maritime mobile satellite communications began with the introduction by the U.S. of the Marisat system in 1976, satisfying a commitment made by COMSAT (Communications Satellite Corp.) in 1973 to provide a maritime satellite service. The Marisat Consortium, spun off by COMSAT, launched three satellites in 1973 - one to serve shipping in the Atlantic, one for the Pacific, and the third as a spare; the spare was subsequently positioned over the Indian Ocean so that the three provided almost global coverage. Each satellite was served by a coast earth station with a 13-m antenna; satellite-earth station links operated in the 6 and 4-GHz bands and the ship-satellite links were at 1.5 and 1.6 GHz. Superceding the limited Marisat system, the INMARSAT Organization, established in July 1979 and first in service on Feb. 1, 1982, now provides communications through a system of Marecs, Intelsat-V, and Marisat satellites. With 41 Signatories by mid-1985, the organization consists of an Assembly, a Council, and a Directorate. Services provided include: telephone; facsimile; low-speed data; high-speed data; telex; telegram; distress, urgency and safety communications; shore-to-ship group calls; various information and assistance services. Coast earth stations, ship earth stations, network coordination stations, and the London headquarters and operations control center are described. Future developments will include an expanded capacity network, digital services, and a role in the Future Global Maritime Distress and Safety System that will use radio beacons that will automatically transmit distress messages to land-based emergency centers in the event of a disaster at sea.

  8. Multi-mission Satellite Management

    Science.gov (United States)

    Jamilkowski, M. L.; Teter, M. A.; Grant, K. D.; Dougherty, B.; Cochran, S.

    2015-12-01

    NOAA's next-generation environmental satellite, the Joint Polar Satellite System (JPSS) replaces the current Polar-orbiting Operational Environmental Satellites (POES). JPSS satellites carry sensors which collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The first JPSS satellite was launched in 2011 and is currently NOAA's primary operational polar satellite. The JPSS ground system is the Common Ground System (CGS), and provides command, control, and communications (C3) and data processing (DP). A multi-mission system, CGS provides combinations of C3/DP for numerous NASA, NOAA, DoD, and international missions. In preparation for the next JPSS satellite, CGS improved its multi-mission capabilities to enhance mission operations for larger constellations of earth observing satellites with the added benefit of streamlining mission operations for other NOAA missions. CGS's multi-mission capabilities allows management all of assets as a single enterprise, more efficiently using ground resources and personnel and consolidating multiple ground systems into one. Sophisticated scheduling algorithms compare mission priorities and constraints across all ground stations, creating an enterprise schedule optimized to mission needs, which CGS executes to acquire the satellite link, uplink commands, downlink and route data to the operations and data processing facilities, and generate the final products for delivery to downstream users. This paper will illustrate the CGS's ability to manage multiple, enterprise-wide polar orbiting missions by demonstrating resource modeling and tasking, production of enterprise contact schedules for NOAA's Fairbanks ground station (using both standing and ad hoc requests), deconflicting resources due to ground outages, and updating resource allocations through dynamic priority definitions.

  9. Research on the new type of multi-functional satellite system for space debris detection

    Science.gov (United States)

    Guo, Linghua; Fu, Qiang; Jiang, Huilin; Xu, Xihe

    2017-05-01

    With the rapid development of space exploration and utilization, orbital debris increases dramatically, leading to great threat to human space activities and spacecraft security. In this paper, a new type of multi-functional space debris satellite system (MSDS) was put forward, which shared main optical system, and possessed functions of multidimensional information detection, polarized remote sensing and high rate transmission. The MSDS system can meet the requirements of detection and identification for the small orbital debris which is 1000km faraway, as well as the requirements of the data transmission by 50 Mbps to 2.5 Gbps@200-1000 km. At the same time, by the method of satellite orbital maneuver and attitude adjusting, the orbital debris information that is real-time, complex and refined, allweather can be acquired and transmitted by the new system. Such new type of multifunctional satellite system can provide important and effective technology for international orbital debris detection.

  10. Handover aspects for a Low Earth Orbit (LEO) CDMA Land Mobile Satellite (LMS) system

    Science.gov (United States)

    Carter, P.; Beach, M. A.

    1993-01-01

    This paper addresses the problem of handoff in a land mobile satellite (LMS) system between adjacent satellites in a low earth orbit (LEO) constellation. In particular, emphasis is placed on the application of soft handoff in a direct sequence code division multiple access (DS-CDMA) LMS system. Soft handoff is explained in terms of terrestrial macroscopic diversity, in which signals transmitted via several independent fading paths are combined to enhance the link quality. This concept is then reconsidered in the context of a LEO LMS system. A two-state Markov channel model is used to simulate the effects of shadowing on the communications path from the mobile to each satellite during handoff. The results of the channel simulation form a platform for discussion regarding soft handoff, highlighting the potential merits of the scheme when applied in a LEO LMS environment.

  11. Aladin transmit-receive optics (TRO): the optical interface between laser, telescope and spectrometers

    Science.gov (United States)

    Mosebach, Herbert; Erhard, Markus; Camus, Fabrice

    2005-09-01

    This paper presents the design and key technologies of the Transmit-Receive Optics (TRO) for the Aladin lidar instrument. The TRO as the central optical interface on the Aladin instrument leading the optical signals from the laser source to the emitting/receiving telescope, and vice versa, the received back scattered signals from the telescope to the spectrometers for Doppler shift evaluation. Additionally, the TRO contains a calibration branch bypassing the telescope and aims at levelling out the received signals in terms of wavelength and signal height changes due to wavelength and intensity variations of the laser. The opto-mechanical concept of the TRO consists of afocal optical groups, which are connected by parallel beams. Extreme requirements have been defined for the TRO on the end-to-end transmission (>=73 %) with an associated effective bandwidth of less than 1 nm over the 200 - 1100 nm spectral range. The achieved solution is presented in this paper. A further feature of the TRO is the use of two so-called aberration generators on the emitting and calibration branch, with which an artificial astigmatism can be realised for eye safety reasons. Its effect on astigmatism is presented. This article also addresses the effort on stray light suppression, which is of extreme importance for the TRO. Special ion plated (IP) optical coatings have been used with superior performance for the TRO, particulary on laser energy resistance and air/vacuum stability. The development of special mounting technologies of optical elements to meet the stringent WFE, stability, and stray light requirements for the TRO are described. Key words : Aeolus Satellite, ALADIN instrument, Lidar, optical design, UV optics manufacturing technologies

  12. Satellite communications principles and applications

    CERN Document Server

    Calcutt, David

    1994-01-01

    Satellites are increasingly used for global communications, as well as for radio and television transmissions. With the growth of mobile communications, and of digital technology, the use of satellite systems is set to expand substantially and already all students of electronics or communications engineering must study the subject.This book steers a middle path between offering a basic understanding of the process of communication by satellite and the methodology used; and the extensive mathematical analysis normally adopted in similar texts. It presents the basic concepts, using as mu

  13. Advanced Communications Technology Satellite (ACTS)

    Science.gov (United States)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  14. The french educational satellite arsene

    Science.gov (United States)

    Danvel, M.; Escudier, B.

    ARSENE (Ariane, Radio-amateur, Satellite pour l'ENseignement de l'Espace) is a telecommunications satellite for Amateur Space Service. Its main feature is that more than 100 students from French engineering schools and universities have been working since 1979 for definition phase and satellite development. The highest IAF awards has been obtained by "ARSENE students" in Tokyo (1980) and Rome (1981). The French space agency, CNES and French aerospace industries are supporting the program. The European Space Agency offered to place ARSENE in orbit on the first Ariane mark IV launch late 1985.

  15. ISDN - The case for satellites

    Science.gov (United States)

    Pelton, Joseph N.; McDougal, Patrick J.

    1987-05-01

    The Integrated Services Digital Network (ISDN) holds much promise for both suppliers and users of telecommunications in the near future. This article examines the role of satellites in this new ISDN environment and emphasizes several advantages of satellites in the ongoing evolution to an all-digital world. In specific, the role of Intelsat, the global satellite system, is discussed with emphasis on Intelsat's digital services which today can offer all the characteristics and standards of ISDN in a flexible, cost-efficient manner.

  16. Leucocytes, cytokines and satellite cells

    DEFF Research Database (Denmark)

    Paulsen, Gøran; Mikkelsen, Ulla Ramer; Raastad, Truls

    2012-01-01

    -damaging exercise', primarily eccentric exercise. We review the evidence for the notion that the degree of muscle damage is related to the magnitude of the cytokine response. In the third and final section, we look at the satellite cell response to a single bout of eccentric exercise, as well as the role...... damage. With the exception of IL-6, the sources of systemic cytokines following exercise remain unclear The satellite cell response to severe muscle damage is related to regeneration, whereas the biological significance of satellite cell proliferation after mild damage or non-damaging exercise remains...

  17. Delay analysis of an integrated voice and data access protocol with collision detection for multimedia satellite networks

    Science.gov (United States)

    Poon, Charles C. K.; Suda, Tatsuya

    1992-03-01

    The novel multiple-access scheme for multimedia satellite networks presented is based on a combination of FDMA and TDMA, integrating both circuit and packet-switching techniques. While the circuit-switching method is used to transmit such stream-type traffic as real-time voice communications, packet-switching is used to transmit such 'bursty' traffic as interactive data. A ground radio network is assumed for control signaling; the tone sense multiple access/partial collision detection scheme is implemented on this network to enhance the integrated access scheme's performance.

  18. Planetary satellites - an update

    Science.gov (United States)

    Beatty, J. K.

    1983-11-01

    General features of all known planetary satellites in the system are provided, and attention is focused on prominent features of several of the bodies. Titan has an atmosphere 1.5 times earth's at sea level, a well a a large body of liquid which may be ethane, CH4, and disolved N2. Uranus has at least five moons, whose masses have recently been recalculated and determined to be consistent with predictions of outer solar system composition. Io's violent volcanic activity is a demonstration of the conversion of total energy (from Jupiter) to heat, i.e., interior melting and consequent volcanoes. Plumes of SO2 have been seen and feature temperatures of up to 650 K. Enceladus has a craterless, cracked surface, indicating the presence of interior ice and occasional breakthroughs from tidal heating. Hyperion has a chaotic rotation, and Iapetus has one light and one dark side, possibly from periodic collisions with debris clouds blasted off the surface of the outer moon Phoebe.

  19. Hubble Space Telescope satellite

    Science.gov (United States)

    Mitchell, R. E.

    1985-01-01

    The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.

  20. Prevalence of Sexually Transmitted Diseases and Blood-Borne Transmitted Infections among Male Patients with Antisocial Personality Disorder

    Directory of Open Access Journals (Sweden)

    Hamza Yıldız

    2015-03-01

    Full Text Available Objective: The aim of this study was to compare the patients who have antisocial personality disorder (ASPD and the healthy individuals in terms of sexually transmitted diseases (STDs and Blood-Borne Transmitted Infections (BTIs prevalences. Methods: This study is a prospective, single-center, open-label, non-randomized controlled clinical study. There were two groups in the study. The patient group consistsed of 100 males who were diagnosed as ASPD with a clinical interview form. The control group consisted of 98 healthy males who did not have any psychiatric disorder. Dermatologic examination was performed, and clinical findings were recorded. Results: The mean age of the patient group was 21.96±2.40 (range 20-37 years. The mean age of the control group was 24.20±2.88 (21-36 years. The most common disease was gonorrhea (25% followed by genital wart (11%, molluskum contagiosum (5%, HBsAg (4%, and HSV-2 seropositivity (4% in the patients group. In the control group, HSV-2 seropositivity (4.08%, genital wart (3.06%, molluskum contagiosum (3.06%, and gonorrhe (1.02% were commonly seen in the control group. STDs and/or BVTIs were found more common in the patients group (82% than that in the control group (45.91% (X2=30.62, p=0.000. Conclusions: The patients with ASPD are at greater risk than normal population to catch a STDs or BTIs because of their lower educational levels and riskier behaviors. This condition entertains a risk in the general population and the patients themselves.

  1. Formulation of geopotential difference determination using optical-atomic clocks onboard satellites and on ground based on Doppler cancellation system

    Science.gov (United States)

    Shen, Ziyu; Shen, Wen-Bin; Zhang, Shuangxi

    2016-08-01

    In this study, we propose an approach for determining the geopotential difference using high-frequency-stability microwave links between satellite and ground station based on Doppler cancellation system. Suppose a satellite and a ground station are equipped with precise optical-atomic clocks (OACs) and oscillators. The ground oscillator emits a signal with frequency fa towards the satellite and the satellite receiver (connected with the satellite oscillator) receives this signal with frequency fb which contains the gravitational frequency shift effect and other signals and noises. After receiving this signal, the satellite oscillator transmits and emits, respectively, two signals with frequencies fb and fc towards the ground station. Via Doppler cancellation technique, the geopotential difference between the satellite and the ground station can be determined based on gravitational frequency shift equation by a combination of these three frequencies. For arbitrary two stations on ground, based on similar procedures as described above, we may determine the geopotential difference between these two stations via a satellite. Our analysis shows that the accuracy can reach 1 m2 s- 2 based on the clocks' inaccuracy of about 10-17 (s s-1) level. Since OACs with instability around 10-18 in several hours and inaccuracy around 10-18 level have been generated in laboratory, the proposed approach may have prospective applications in geoscience, and especially, based on this approach a unified world height system could be realized with one-centimetre level accuracy in the near future.

  2. Commercial satellite broadcasting for Europe

    Science.gov (United States)

    Forrest, J. R.

    1988-12-01

    A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future.

  3. Biogeography based Satellite Image Classification

    CERN Document Server

    Panchal, V K; Kaur, Navdeep; Kundra, Harish

    2009-01-01

    Biogeography is the study of the geographical distribution of biological organisms. The mindset of the engineer is that we can learn from nature. Biogeography Based Optimization is a burgeoning nature inspired technique to find the optimal solution of the problem. Satellite image classification is an important task because it is the only way we can know about the land cover map of inaccessible areas. Though satellite images have been classified in past by using various techniques, the researchers are always finding alternative strategies for satellite image classification so that they may be prepared to select the most appropriate technique for the feature extraction task in hand. This paper is focused on classification of the satellite image of a particular land cover using the theory of Biogeography based Optimization. The original BBO algorithm does not have the inbuilt property of clustering which is required during image classification. Hence modifications have been proposed to the original algorithm and...

  4. Virtual Satellite Integration Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An integrated environment for rapid design studies of small satellite missions will be developed. This environment will be designed to streamline processes at the...

  5. Virtual Satellite Integration Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advatech Pacific proposes to develop a Virtual Satellite Integration Environment (VSIE) for the NASA Ames Mission Design Center. The VSIE introduces into NASA...

  6. Satellite Teleconferencing in the Caribbean.

    Science.gov (United States)

    Sankar, Hollis C.

    1985-01-01

    Discusses the need for, and the development, use, and future trends of, the University of the West Indies Distance Teaching Experiment, which utilizes telephone and communications satellite technology teleconferencing to extend educational opportunities to the peoples of the Caribbean. (MBR)

  7. Geography with the environmental satellites

    Directory of Open Access Journals (Sweden)

    J.P. Gastellu Etchegorry

    2013-07-01

    Full Text Available Coarse spatial resolution, high temporal frequency data from the earth polar orbiting (NOAA. HACMM, Nimbus, etc. satellites and from the geostationary (GOES. Meteosat, and GMS satellites are presented to demonstrate their utility for monitoring terrestrial and atmospheric processes. The main characteristics of these ,satellites and of the instruments on board are reviewed. In order to be useful for environmental assessments. the remotely sensed data must be processed (atmospheric and geometric corrections, etc.. The NOAA Center provides a wide range of already processed data. such as meteorological. oceanic, hydrologic and vegetation products; o rough description of these preprocessed data is given in this article. Finally, some examples of applicotions in Southeast Asia and especially in Indonesia, are described, i.e.: agroecosystem, drought and oceanic monitoring. The paper concludes that coarse resolution, high temporal frequency ,satellite data are very valuable for environmental studies. the emphasis being laid on the improve. ment of the crop and drought assessment programmes.

  8. women Contrlbute to Satellite Technology

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    IN the early morning of August 14, 1992, at the Xichang satellite launching center, China Central Television Station was about to do a live, worldwide broadcast on the launching of an Australian communications satellite made by the United States. With the order of the commander, "Ignition," people could watch the white rocket rise, pierce the blue sky and race toward the space with a long flaming tail trailing behind it.

  9. Existence of undiscovered Uranian satellites

    Energy Technology Data Exchange (ETDEWEB)

    Boice, D.C.

    1986-04-01

    Structure in the Uranian ring system as observed in recent occultations may contain indirect evidence for the existence of undiscovered satellites. Using the Alfven and Arrhenius (1975, 1976) scenario for the formation of planetary systems, the orbital radii of up to nine hypothetical satellites interior to Miranda are computed. These calculations should provide interesting comparisons when the results from the Voyager 2 encounter with Uranus are made public. 15 refs., 1 fig., 1 tab.

  10. Radio interferometry and satellite tracking

    CERN Document Server

    Kawase, Seiichiro

    2012-01-01

    Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describ

  11. Papanicolaou smears induce partial immunity against sexually transmitted viral infections.

    Science.gov (United States)

    Shapiro, Samuel; Hoffman, Margaret; Constant, Deborah; Rosenberg, Lynn; Carrara, Henri; Allan, Bruce Rider; Marais, Dianne Jean; Passmore, Jo-Ann Shelley; Williamson, Anna-Lise

    2007-11-01

    In a case-control study of hormonal contraceptives and invasive cervical cancer, an unexpected finding was a substantial decline in the prevalence of high-risk human papillomavirus (HPV) infection according to the lifetime number of Pap smears received. Here we assess the risk of 3 sexually transmitted viral infections -- herpes simplex virus 2 (HSV2), HPV, and human immunodeficiency virus (HIV) 1 and 2 -- in relation to the lifetime receipt of Pap smears. Stored sera taken from 1540 controls were tested for HSV2 and HIV; cervical scrapings were tested for HPV. Confounder-adjusted odds ratios for the lifetime receipt of Pap smears were estimated, relative to never having had a Papanicolau test. For ever-receipt of a Papanicolau test, the odds ratios for HSV2 and HPV were 0.7 (95% confidence interval = 0.5-0.9) and 0.5 (0.3-0.7), respectively, and there were dose-response trends according to the lifetime number of Pap smears received (test for trend P = 0.02 and 0.04, respectively). For HSV2 the odds ratios according to last receipt declined from 0.8 for 10 or more years previously to 0.4 for <1 year previously (trend P = 0.002). For HPV the ORs were 0.4 (0.3-0.7) for last receipt 5-9 years previously and 0.5 (0.4-0.8) for less than 5 years previously; for HIV the odds ratio for last receipt less than 5 years previously was 0.4 (0.3-0.9). For HSV2 and HIV the crude odds ratio estimates were systematically lower than the adjusted estimates, and residual confounding cannot be ruled out. In particular, the true number of sexual partners may have been under-reported, and there was no information on the sexual activity of the male partners, or on other health behaviors of the women or their partners. We hypothesize that Pap smears may provoke a short-term immune response against sexually transmitted viral infections.

  12. Prevention of AIDS and sexually transmitted infections (Review Paper

    Directory of Open Access Journals (Sweden)

    G.P. Talwar

    2001-10-01

    Full Text Available Abnormal vaginal discharge due to reproductive tract infections (RTIs is widely prevalent in the country. According to WHO, over 300 million new cases of sexually-transmitted infections (excluding HIV occur each year. In addition to these, HIV infection is spreading rapidly in the country with over 3.7 million sero-positive cases (from zero within 15 years.. The predominant mode of transmission of HIV is by heterosexual route. The multidrug regime for treatment is expensive (about $10,000 per year which is beyond the reach of most of the people. No viable vaccine preventing AIDS infection is in sight. Under these circumstances, safe sex is the best recourse, which demands consistent and proper use of condoms. This does not take place to the extent necessary for preventing the transmission of HIV and other sexually-transmitted infections. A polyherbal tablet for intravaginal use by women has been developed and a polyherbal cream, for use by both men and women, which has a wide spectrum antimicrobial action. Amongst others, these inhibit the growth of Neisseria gonorrhea (including strains resistant to penicillin. normal and multidrug-resistant isolates of urinary tract E. coli, Candida albicans. Candida krusei and Candida tropicalis. Applied intravaginally, these prevent the transmission of Herpes simplex 2 and Chlamydia Irachomatis in progestin-sensitised mice. Studies conducted at the Institut Pasteur. Paris and Conrad Norfolk, USA, have demonstrated high virucidal action of these formulations against HIV . Both formulations have undergone phase I clinical trials in five major centres in India and abroad, which have indicated the complete safety of these products without any local or systemic side effects. The Drug Controller of India and the Institutional Ethics Committees have approved phase II clinical trials. The first of these trials was conducted in 88 women with abnormal vaginal discharge due to genital pathogens at the Postgraduate

  13. Spanish Earth Observation Satellite System

    Science.gov (United States)

    Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.

    2010-12-01

    The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

  14. Satellite medical centers project

    Science.gov (United States)

    Aggarwal, Arvind

    2002-08-01

    World class health care for common man at low affordable cost: anywhere, anytime The project envisages to set up a national network of satellite Medical centers. Each SMC would be manned by doctors, nurses and technicians, six doctors, six nurses, six technicians would be required to provide 24 hour cover, each SMC would operate 24 hours x 7 days. It would be equipped with the Digital telemedicine devices for capturing clinical patient information and investigations in the form of voice, images and data and create an audiovisual text file - a virtual Digital patient. Through the broad band connectivity the virtual patient can be sent to the central hub, manned by specialists, specialists from several specialists sitting together can view the virtual patient and provide a specialized opinion, they can see the virtual patient, see the examination on line through video conference or even PCs, talk to the patient and the doctor at the SMC and controlle capturing of information during examination and investigations of the patient at the SMC - thus creating a virtual Digital consultant at the SMC. Central hub shall be connected to the doctors and consultants in remote locations or tertiary care hospitals any where in the world, thus creating a virtual hub the hierarchical system shall provide upgradation of knowledge to thedoctors in central hub and smc and thus continued medical education and benefit the patient thru the world class treatment in the smc located at his door step. SMC shall be set up by franchisee who shall get safe business opportunity with high returns, patients shall get Low cost user friendly worldclass health care anywhere anytime, Doctors can get better meaningful selfemplyment with better earnings, flexibility of working time and place. SMC shall provide a wide variety of services from primary care to world class Global consultation for difficult patients.

  15. Satellite Attitude from a Raven Class Telescope

    Science.gov (United States)

    2010-09-01

    Cache MATLAB was used as an interface to the jSim libraries, including orbit propagation, Earth Track determination, and satellite orientation methods...collection opportunities of the satellite. The combined software tool calculates the satellite orientation required to image the asset location... satellite orientation estimations, with only the photometric signatures with strong features being correctly estimated. The strong features that

  16. CHINA LAUNCHES 2 SCIENTIFIC EXPERIMENT SATELLITES

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China placed 2 scientific experiment satellites into preset orbits atop a LM-4B launch vehicle on Sept. 9, 2004. A LM-4B blasted off at 7:14 am from Taiyuan Satellite Launch Center in Shanxi Province. Sources from the Xi'an Satellite Monitor and Control Center said that one satellite,

  17. China Launches First Ever Nano-satellite

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    China successfully launched two scientific satellites, including a nano-satellite for the first time, heralding a breakthrough in space technology. A LM-2C rocket carrying Nano-Satellite I (NS-1), which weighs just 25kg and an Experiment Satellite I, weighing 204kg blasted off at 11:59 p.m. on April 18,

  18. Fast Development Of China's Small Satellite Industry

    Institute of Scientific and Technical Information of China (English)

    Sun Hongjin

    2009-01-01

    @@ China Spacesat Co., Ltd of China Academy of Space Technology (CAST) recently said, along with the successful launch of HJ-1A/B for the environment and disaster monitoring and forecasting small satellite constellation and after years of efforts, small satellite development technology has achieved fruitful results, and the development status has been greatly improved.China's small satellite technology has realized a great-leap-forward in development from a single satellite model to series model, from the satellite program to space industry. China has explored a development road for China's small satellite industrialization, and a modern small satellite development base has resulted.

  19. Migrant labor and sexually transmitted disease: AIDS in Africa.

    Science.gov (United States)

    Hunt, C W

    1989-12-01

    Acquired immune deficiency syndrome (AIDS) is worldwide, but the clinical and epidemiological pattern of the disease in Africa is different from that in developed areas. "Type 1 AIDS" occurs in industrialized North America and Europe; it has a distinctive sex ratio (16:1) and risk pattern of IV drug use and sexual practices. "Type 2 AIDS" occurs in Third World countries, particularly in eastern, southern, and central Africa. It is characterized by an entirely different sex ratio (1:1) and by distinctively different risk patterns. Both epidemics are caused by the HIV-1 virus. The key concept for understanding the origins of the differences between Type 1 and Type 2 AIDS is the migratory labor system in eastern, central, and southern Africa. This system causes long absences, increased family breakdown, and increased numbers of sexual partners. Historically the organization of this labor market has created a population which suffers from epidemics of sexually transmitted diseases. These historical patterns are presented as evidence for the contemporary transmission of AIDS. When contemporary AIDS and HIV-1 seropositivity prevalence data are examined, a systematic temporal and geographic pattern emerges for the AIDS epidemic in Africa. Despite a paucity of good data, the prevalence data from eastern, central, and southern Africa support the thesis of migrant labor's role in the transmission of AIDS.

  20. The role of fear in predicting sexually transmitted infection screening.

    Science.gov (United States)

    Shepherd, Lee; Smith, Michael A

    2017-07-01

    This study assessed the extent to which social-cognitive factors (attitude, subjective norm and perceived control) and the fear of a positive test result predict sexually transmitted infection (STI) screening intentions and subsequent behaviour. Study 1 (N = 85) used a longitudinal design to assess the factors that predict STI screening intention and future screening behaviour measured one month later at Time 2. Study 2 (N = 102) used an experimental design to determine whether the relationship between fear and screening varied depending on whether STI or HIV screening was being assessed both before and after controlling for social-cognitive factors. Across the studies the outcome measures were sexual health screening. In both studies, the fear of having an STI positively predicted STI screening intention. In Study 1, fear, but not the social-cognitive factors, also predicted subsequent STI screening behaviour. In Study 2, the fear of having HIV did not predict HIV screening intention, but attitude negatively and response efficacy positively predicted screening intention. This study highlights the importance of considering the nature of the health condition when assessing the role of fear on health promotion.

  1. Mechanisms and consequences of paternally transmitted chromosomal abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F; Wyrobek, A J

    2005-04-05

    Paternally transmitted chromosomal damage has been associated with pregnancy loss, developmental and morphological defects, infant mortality, infertility, and genetic diseases in the offspring including cancer. There is epidemiological evidence linking paternal exposure to occupational or environmental agents with an increased risk of abnormal reproductive outcomes. There is also a large body of literature on germ cell mutagenesis in rodents showing that treatment of male germ cells with mutagens has dramatic consequences on reproduction producing effects such as those observed in human epidemiological studies. However, we know very little about the etiology, transmission and early embryonic consequences of paternally-derived chromosomal abnormalities. The available evidence suggests that: (1) there are distinct patterns of germ cell-stage differences in the sensitivity of induction of transmissible genetic damage with male postmeiotic cells being the most sensitive; (2) cytogenetic abnormalities at first metaphase after fertilization are critical intermediates between paternal exposure and abnormal reproductive outcomes; and, (3) there are maternally susceptibility factors that may have profound effects on the amount of sperm DNA damage that is converted into chromosomal aberrations in the zygote and directly affect the risk for abnormal reproductive outcomes.

  2. [Microbiological diagnosis of sexually-transmitted infection (2007)].

    Science.gov (United States)

    Vázquez, Fernando; Lepe, José Antonio; Otero, Luis; Blanco, María Antonia; Aznar, Javier

    2008-01-01

    Sexually transmitted infections (STIs) constitute an important world-wide public health problem. The use of sensitive and specific laboratory methods for diagnosing this condition is crucial to reduce the transmission and sequelae of STI. The present review describes current microbiological methods for the diagnosis of STIs. Neisseria gonorrhoeae and Chlamydia trachomatis are the pathogens most frequently involved in urethral and cervical infection. Culture continues to be the gold standard for diagnosing gonorrhea. Nucleic acid amplification assays are considered the new gold standard for C. trachomatis, although culture is till the most specific technique. Genital ulcers due to Treponema pallidum, Haemophilus ducreyi, or herpes simplex virus have little clinical and bacteriological correlation; therefore, it is essential to establish the microbiological diagnosis. Lesions present in the primary or secondary period of syphilis can be diagnosed by dark field microscopy. Serologic diagnosis for the remaining periods is based on non-treponemal tests associated with confirmatory treponemal tests. Cell culture is considered the gold standard for herpes simplex virus although molecular methods also have a sensitivity and specificity near 100%. Currently, microbiologic diagnosis of H. ducreyi and venereal lymphogranuloma is achieved with the use of molecular methods on samples obtained from the ulceration or lymph adenopathy. The diagnosis of genital warts in immunocompetent patients is based on clinical findings in most cases because the lesions are sufficiently characteristic. Culture is considered the reference method in Trichomonas vaginalis infection.

  3. Mitigating the Risk of Transfusion-Transmitted Dengue in Australia

    Directory of Open Access Journals (Sweden)

    Kelly Rooks

    2016-01-01

    Full Text Available Dengue viruses (DENV 1–4 are a risk to transfusion safety, with several transfusion-transmitted (TT cases reported globally. DENV 1–4 are endemic in over 100 countries, with seasonal outbreaks occurring in northeastern Australia. To mitigate TT-DENV risk in Australia, fresh blood components are not manufactured from donors returning from any area (domestic/overseas with known dengue transmission. Alternatively, TT-DENV risk may be mitigated using an appropriate blood donor screening assay. We aimed to determine the rate of dengue infection in donors during dengue outbreaks in Australia. Plasma samples were collected from blood donors during local dengue outbreaks. All samples were tested for the presence of DENV RNA and selected samples were tested for DENV antigen (nonstructural protein 1, NS1 with two assays. No donors residing in high risk areas had detectable levels of DENV RNA or NS1 and no cases of DENV viremia were detected in blood donors residing in areas of Australia experiencing DENV outbreaks. Definitive conclusions could not be drawn from this study; however, the lack of detection of DENV RNA or antigen in donations suggests that the current risk of TT-DENV is low and maintaining the fresh component restriction for “at-risk” donors is appropriate.

  4. Measuring disparities in the incidence of sexually transmitted diseases.

    Science.gov (United States)

    Hoover, Karen; Bohm, Michele; Keppel, Kenneth

    2008-12-01

    The Centers for Disease Control and Prevention (CDC) defines a health disparity as a "[health] difference that occurs by gender, race or ethnicity, education or income, disability, geographic location, or sexual orientation." Health equity is achieved by eliminating health disparities or inequalities. Measuring health disparities is a critical first step toward reducing differences in health outcomes. To determine the methods to be used in measuring a health disparity, several decisions must be made, which include: (1) selecting a reference group for the comparison of 2 or more groups; (2) determining whether a disparity should be measured in absolute or in relative terms; (3) opting to measure health outcomes or health indicators expressed as adverse or favorable events; (4) selecting a method to monitor a disparity over time; and (5) choosing to measure a disparity as a pair-wise comparison between 2 groups or in terms of a summary measure of disparity among all groups for a particular characteristic. Different choices may lead to different conclusions about the size and direction of health disparities at a point in time and changes in disparities over time.The objective of this article is to review the methods for measuring health disparities, provide examples of their use, and make specific recommendations for measuring disparities in the incidence of sexually transmitted diseases (STDs).

  5. DNA Microarray Characterization of Pathogens Associated with Sexually Transmitted Diseases.

    Science.gov (United States)

    Cao, Boyang; Wang, Suwei; Tian, Zhenyang; Hu, Pinliang; Feng, Lu; Wang, Lei

    2015-01-01

    This study established a multiplex PCR-based microarray to detect simultaneously a diverse panel of 17 sexually transmitted diseases (STDs)-associated pathogens including Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma, Herpes simplex virus (HSV) types 1 and 2, and Human papillomavirus (HPV) types 6, 11, 16, 18, 31, 33, 35, 39, 54 and 58. The target genes are 16S rRNA gene for N. gonorrhoeae, M. genitalium, M. hominism, and Ureaplasma, the major outer membrane protein gene (ompA) for C. trachomatis, the glycoprotein B gene (gB) for HSV; and the L1 gene for HPV. A total of 34 probes were selected for the microarray including 31 specific probes, one as positive control, one as negative control, and one as positional control probe for printing reference. The microarray is specific as the commensal and pathogenic microbes (and closely related organisms) in the genitourinary tract did not cross-react with the microarray probes. The microarray is 10 times more sensitive than that of the multiplex PCR. Among the 158 suspected HPV specimens examined, the microarray showed that 49 samples contained HPV, 21 samples contained Ureaplasma, 15 contained M. hominis, four contained C. trachomatis, and one contained N. gonorrhoeae. This work reports the development of the first high through-put detection system that identifies common pathogens associated with STDs from clinical samples, and paves the way for establishing a time-saving, accurate and high-throughput diagnostic tool for STDs.

  6. The social behavior and the evolution of sexually transmitted diseases

    Science.gov (United States)

    Gonçalves, Sebastián; Kuperman, Marcelo

    2003-10-01

    We introduce a model for the evolution of sexually transmitted diseases, in which the social behavior is incorporated as a determinant factor for the further propagation of the infection. The system may be regarded as a society of agents where in principle, anyone can sexually interact with any other one in the population, indeed, in this contribution only the homosexual case is analyzed. Different social behaviors are reflected in a distribution of sexual attitudes ranging from the more conservative to the more promiscuous. This is measured by what we call the promiscuity parameter. In terms of this parameter, we find a critical behavior for the evolution of the disease. There is a threshold below which the epidemic does not occur. We relate this critical value of promiscuity to what epidemiologists call the basic reproductive number, connecting it with the other parameters of the model, namely the infectivity and the infective period in a quantitative way. We consider the possibility of subjects to be grouped in couples.

  7. Voluntary vaccination strategy and the spread of sexually transmitted diseases.

    Science.gov (United States)

    Xu, Fei; Cressman, Ross

    2016-04-01

    In this work, we investigate the spread and control of sexually transmitted diseases when a game-theory based vaccination strategy is involved. An individual's decision on vaccination uptake may follow a cost-benefit analysis since the individual obtains immunity against the disease from the vaccination and, at the same time, may have some perceived side effects. Evolutionary game theory is integrated into the epidemic model to reveal the relationship between individuals' voluntary decisions on vaccination uptake and the spread and control of such diseases. We show that decreasing the perceived cost of taking vaccine or increasing the payoff from social obligation is beneficial to controlling the disease. It is also shown how the "degree of rationality" of males and females affects the disease spread through the net payoff of the game. In particular, individual awareness of the consequences of the disease on the infectives also contributes to slowing down the disease spread. By analyzing an asymmetric version of our evolutionary game, it is shown that the disease is better controlled when individuals are more sensitive to fitness differences when net payoff is positive than when it is negative.

  8. Dimension-based quality modeling of transmitted speech

    CERN Document Server

    Wältermann, Marcel

    2013-01-01

    In this book, speech transmission quality is modeled on the basis of perceptual dimensions. The author identifies those dimensions that are relevant for today's public-switched and packet-based telecommunication systems, regarding the complete transmission path from the mouth of the speaker to the ear of the listener. Both narrowband (300-3400 Hz) as well as wideband (50-7000 Hz) speech transmission is taken into account. A new analytical assessment method is presented that allows the dimensions to be rated by non-expert listeners in a direct way. Due to the efficiency of the test method, a relatively large number of stimuli can be assessed in auditory tests. The test method is applied in two auditory experiments. The book gives the evidence that this test method provides meaningful and reliable results. The resulting dimension scores together with respective overall quality ratings form the basis for a new parametric model for the quality estimation of transmitted speech based on the perceptual dimensions. I...

  9. ECENT ADVANCES IN KNOWLEDGE OF SOIL-TRANSMITTED HELMINTHS

    Directory of Open Access Journals (Sweden)

    Paul C. Beaver

    1975-07-01

    Full Text Available New observations in recent years have accented differences between the two common hookworms, Ancylostoma duodenale and Necator americanus,"nwith respect to modes of transmision and pathogenicity, and have established Ancylostoma ceylanicum as a species distinct from A. braziliense. Transmammary and paratenic transmission are now considered to be natural modes of infection in Ancylostoma caninum and possibly 111 other Ancylostoma species including A. duodenale, but not in Necator. The question of relative blood losses from laceration hemorrhage and blood-sucking in hookworm anemia is unresolved. The prevalence of Loeffler's syndrome in pulmonary ascariasis appears to be greatest in areas where transmission is sharply seasonal. Recent studies have failed to confirm reports of blood-sucking by Trichuris. Milk-borne transmission from mother to the newborn has been demonstrated for numberous species of Strongyloides not including S. stercoralis. Zoonotic soil-transmitted helminths 0; dogs and cats have become recognized as frequently causing visceral larva migrans and occasionally blindness in most parts of the world. Two major advances were made in diagnostic techniques - the Harada-Mori test-tube hookworm culture for species diagnosis and the Kato cellophane-covered thick fecal film ror ranid and quantitative diagnosis of intestinal helminth infections.

  10. [Awareness and education regarding sexually transmitted diseases among undergraduate students].

    Science.gov (United States)

    Castro, Eneida Lazzarini de; Caldas, Tânia Alencar de; Morcillo, André Moreno; Pereira, Elisabete Monteiro de Aguiar; Velho, Paulo Eduardo Neves Ferreira

    2016-06-01

    Sexually transmitted diseases (STDs) are the main global cause of acute illness and death and represent a high socioeconomic cost. Undergraduate students are highly exposed to STDs. The research developed at UNICAMP sought to quantify and generate self-perception of knowledge(or lack thereof) about STDs, as well as evaluate the interest of the students in a course on the topic. The data collection instrument was a questionnaire sent electronically to students about to graduate at the end of 2011 and to freshmen in 2012. The questionnaire was answered by 1,448 seniors and 371 freshmen. Twenty percent of seniors and 38% of freshmen had no sexual activity. Among sexually active students, 26.9% had no regular partner and 28.2% more than two partners per year. The condom was used by 99% of students, but less than 20% used them appropriately. About 80% were unaware that condoms do not provide protection outside the barrier area; they intended to read more about STDs and learnt something about the subject. Nearly half of the students considered that a course should be offered to all undergraduates. These findings will be of use in defining strategies for prevention and the teaching tool could be used in other learning environments.

  11. Correlates of sexually transmitted infections in young Australian women.

    Science.gov (United States)

    Khan, Asaduzzaman; Hussain, Rafat; Schofield, Margot

    2005-07-01

    The study examined correlates of three common sexually transmitted infections (STIs) among Australian women. The sample comprised 9582 women aged 22--27 years who took part in the second postal survey in 2000, of the young cohort of the Australian Longitudinal Study on Women's Health.Self-reported rates of diagnosis in past four years were: chlamydia 1.47%(n=141), genital herpes 1.75% (n=168), and genital warts 3.45% (n=331). Multivariate analyses revealed that the odds of all three STIs increased with number of male sexual partners and illicit drug use. Younger and rural women had higher odds of being diagnosed with chlamydia. The odds of both genital herpes and genital warts were higher with longer oral contraceptive pill use and higher stress, while women who had experienced violence were found to have higher odds of herpes.The identification of factors associated with common STIs among young Australian women will inform better-targeted health promotion and disease prevention programmes.

  12. On the power amplifier nonlinearity in MIMO transmit beamforming systems

    KAUST Repository

    Qi, Jian

    2012-03-01

    In this paper, single-carrier multiple-input multiple-output (MIMO) transmit beamforming (TB) systems in the presence of high-power amplifier (HPA) nonlinearity are investigated. Specifically, due to the suboptimality of the conventional maximal ratio transmission/maximal ratio combining (MRT/MRC) under HPA nonlinearity, we propose the optimal TB scheme with the optimal beamforming weight vector and combining vector, for MIMO systems with nonlinear HPAs. Moreover, an alternative suboptimal but much simpler TB scheme, namely, quantized equal gain transmission (QEGT), is proposed. The latter profits from the property that the elements of the beamforming weight vector have the same constant modulus. The performance of the proposed optimal TB scheme and QEGT/MRC technique in the presence of the HPA nonlinearity is evaluated in terms of the average symbol error probability and mutual information with the Gaussian input, considering the transmission over uncorrelated quasi-static frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects on the performance of several system parameters, namely, the HPA parameters, numbers of antennas, quadrature amplitude modulation modulation order, number of pilot symbols, and cardinality of the beamforming weight vector codebook for QEGT. © 2012 IEEE.

  13. Light Conduction Capability of Different Light-Transmitting FRC Posts

    Directory of Open Access Journals (Sweden)

    Saied Mostafa Moazzami

    2013-01-01

    Full Text Available Introduction: Application of light transmitting posts to restore greatly damaged endodontically treated teeth has been increased. It is suspected that light intensity decreases as it passes throughout different materials. This can reduce the degree of conversion required for adequate bond strength throughout the length of these posts. The objective of this study was to evaluate the amount of light intensity reduction after passing through different depths of FRC posts. Methods: Four groups of five extracted human central incisors were prepared to cement four types of FRC posts with Panavia F 2 resin cement. The apical end of the posts were exposed by sectioning with a diamond disk and then polished. The light intensity measurement was performed using a micro-voltmeter in 8 points or depths with 2mm intervals beginning from the apical depth of 16mm up to a coronal depth of 6mm. Two different output light intensities [HIP (High Intensity Program and LOP (Low Intensity Program] were evaluated. Results: Statistical analysis showed significant differences in light intensity at various depths between 6 and 16mm in all groups. These reductions were linear in all specimens; however, the rate of reduction was dissimilar among different FRC posts. HIP and LOP light exposure modes had not the same rate of light reduction. Conclusion: Light intensity decreased dramatically after passing through different depths of FRC posts. None of the posts had sufficient enough light transmission for satisfactory polymerization at the apical and middle levels.

  14. Light Conduction Capability of Different Light-Transmitting

    Directory of Open Access Journals (Sweden)

    Saied Mostafa Moazzami

    2012-09-01

    Full Text Available Introduction: Application of light transmitting posts to restore greatly damaged endodontically treated teeth has been increased. It is suspected that light intensity decreases as it passes throughout different materials. This can reduce the degree of conversion required for adequate bond strength throughout the length of these posts. The objective of this study was to evaluate the amount of light intensity reduction after passing through different depths of FRC posts. Methods: Four groups of five extracted human central incisors were prepared to cement four types of FRC posts with Panavia F 2 resin cement. The apical end of the posts were exposed by sectioning with a diamond disk and then polished. The light intensity measurement was performed using a micro-voltmeter in 8 points or depths with 2mm intervals beginning from the apical depth of 16mm up to a coronal depth of 6mm. Two different output light intensities [HIP (High Intensity Program and LOP (Low Intensity Program] were evaluated. Results: Statistical analysis showed significant differences in light intensity at various depths between 6 and 16mm in all groups. These reductions were linear in all specimens; however, the rate of reduction was dissimilar among different FRC posts. HIP and LOP light exposure modes had not the same rate of light reduction. Conclusion: Light intensity decreased dramatically after passing through different depths of FRC posts. None of the posts had sufficient enough light transmission for satisfactory polymerization at the apical and middle levels.

  15. Circular polarization of transmitted light by sapphirinidae copepods.

    Directory of Open Access Journals (Sweden)

    Yuval Baar

    Full Text Available Circularly polarized light, rare in the animal kingdom, has thus far been documented in only a handful of animals. Using a rotating circular polarization (CP analyzer we detected CP in linearly polarized light transmitted through epipelagic free living Sapphirina metallina copepods. Both left and right handedness of CP was detected, generated from specific organs of the animal's body, especially on the dorsal cephalosome and prosome. Such CP transmittance may be generated by phase retardance either in the muscle fibers or in the multilayer membrane structure found underneath the cuticle. Although the role, if any, played by circularly polarized light in Sapphirinidae has yet to be clarified, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication.Planktonic Sapphirinidae copepods were found to circularly polarize the light passing through them. Circular polarization may be created by unique, multilayered features of the membrane structure found under their cuticle or by organized muscle fibers.

  16. Trichomoniasis as sexually transmitted disease in sex partners

    Directory of Open Access Journals (Sweden)

    Parvathi C

    1998-01-01

    Full Text Available Study of 30 male consorts of 30 cases of vaginal trichomoniasis with high levels of parasitic infection was undertaken to evaluate the sexually transmitted role of trichomoniasis in sex partners. There were 20 symptomatic and 10 asymptomatic male partners, who revealed T. vaginalis in 80.0% and 60.0 of the cases respectively and the overall prevalence was 73.3% (22 Of 30. T. vaginalis was detected in 83.3% male with urethritis and 50.0% males with prostatitis. Detection of trichomonas in urethral discharge, morning drop secretion, urine deposit and prostatic fluid was 80.0%, 50.0% 35.7% and 21.4% in that order. It is evident from these results that the sex consorts of all cases of trichomoniasis should be considered as harbouring T. vaginalis in their genito-urinary tract as carriers and be treated to break the chain of transmission. Fontanna smear was superior to culture and wet mount in the detection of T. vaginalis, the success rates being 73.3%, 63.3% and 53.3%. A good correlation was observed between smear and culture at high levels of parasitic infection.

  17. Aerosols transmit prions to immunocompetent and immunodeficient mice.

    Directory of Open Access Journals (Sweden)

    Johannes Haybaeck

    Full Text Available Prions, the agents causing transmissible spongiform encephalopathies, colonize the brain of hosts after oral, parenteral, intralingual, or even transdermal uptake. However, prions are not generally considered to be airborne. Here we report that inbred and crossbred wild-type mice, as well as tga20 transgenic mice overexpressing PrP(C, efficiently develop scrapie upon exposure to aerosolized prions. NSE-PrP transgenic mice, which express PrP(C selectively in neurons, were also susceptible to airborne prions. Aerogenic infection occurred also in mice lacking B- and T-lymphocytes, NK-cells, follicular dendritic cells or complement components. Brains of diseased mice contained PrP(Sc and transmitted scrapie when inoculated into further mice. We conclude that aerogenic exposure to prions is very efficacious and can lead to direct invasion of neural pathways without an obligatory replicative phase in lymphoid organs. This previously unappreciated risk for airborne prion transmission may warrant re-thinking on prion biosafety guidelines in research and diagnostic laboratories.

  18. On Secure NOMA Systems with Transmit Antenna Selection Schemes

    KAUST Repository

    Lei, Hongjiang

    2017-08-09

    This paper investigates the secrecy performance of a two-user downlink non-orthogonal multiple access systems. Both single-input and single-output and multiple-input and singleoutput systems with different transmit antenna selection (TAS) strategies are considered. Depending on whether the base station has the global channel state information of both the main and wiretap channels, the exact closed-form expressions for the secrecy outage probability (SOP) with suboptimal antenna selection and optimal antenna selection schemes are obtained and compared with the traditional space-time transmission scheme. To obtain further insights, the asymptotic analysis of the SOP in high average channel power gains regime is presented and it is found that the secrecy diversity order for all the TAS schemes with fixed power allocation is zero. Furthermore, an effective power allocation scheme is proposed to obtain the nonzero diversity order with all the TAS schemes. Monte-Carlo simulations are performed to verify the proposed analytical results.

  19. Potential drug development candidates for human soil-transmitted helminthiases.

    Directory of Open Access Journals (Sweden)

    Piero Olliaro

    2011-06-01

    Full Text Available Few drugs are available for soil-transmitted helminthiasis (STH; the benzimidazoles albendazole and mebendazole are the only drugs being used for preventive chemotherapy as they can be given in one single dose with no weight adjustment. While generally safe and effective in reducing intensity of infection, they are contra-indicated in first-trimester pregnancy and have suboptimal efficacy against Trichuris trichiura. In addition, drug resistance is a threat. It is therefore important to find alternatives.We searched the literature and the animal health marketed products and pipeline for potential drug development candidates. Recently registered veterinary products offer advantages in that they have undergone extensive and rigorous animal testing, thus reducing the risk, cost and time to approval for human trials. For selected compounds, we retrieved and summarised publicly available information (through US Freedom of Information (FoI statements, European Public Assessment Reports (EPAR and published literature. Concomitantly, we developed a target product profile (TPP against which the products were compared.The paper summarizes the general findings including various classes of compounds, and more specific information on two veterinary anthelmintics (monepantel, emodepside and nitazoxanide, an antiprotozoal drug, compiled from the EMA EPAR and FDA registration files.Few of the compounds already approved for use in human or animal medicine qualify for development track decision. Fast-tracking to approval for human studies may be possible for veterinary compounds like emodepside and monepantel, but additional information remains to be acquired before an informed decision can be made.

  20. Transmitting time-dependent multimedia data in FDDI networks

    Science.gov (United States)

    Lim, Cheng-Chew; Yao, L.; Zhao, Wei

    1993-01-01

    Timely delivery of multimedia data is one of the key requirements in a distributed multimedia system. In a token ring network, this can be achieved by a proper control of channel access. FDDI uses a timed token MAC protocol to control the token rotation time. During network initialization, a protocol parameter called target token rotation time (TTRT) is determined. Its value indicates the expected token rotation time. Each node is assigned a fraction of the TTRT, known as synchronous bandwidth, for transmitting its synchronous messages which may be deadline constrained. In this paper, we study methods used for setting the protocol parameters such as TTRT and synchronous bandwidth. The goal is to satisfy the message deadlines. In particular, we discuss the use of the normalized proportional scheme for allocating the synchronous bandwidth. We derive a condition on the utilization factor for ensuring timely delivery of all synchronous messages, and show that 33% utilization is the tight lower bound, regardless of the number of nodes, message lengths, periods, etc. Based on this scheme, we address proper selection of TTRT and trade-off between buffer size and the capability of meeting message deadlines.

  1. Antibiotic resistance in prevalent bacterial and protozoan sexually transmitted infections

    Directory of Open Access Journals (Sweden)

    Karl Krupp

    2015-01-01

    Full Text Available The emergence of multi-drug resistant sexually transmitted infections (STIs is causing a treatment crisis across the globe. While cephalosporin-resistant gonorrhea is one of the most pressing issues, extensively antibiotic resistant Chlamydia trachomatis and Mycoplasma hominis are also becoming commonplace. Experts have suggested that the failure of current treatment regimens are "largely inevitable" and have called for entirely new classes of antimicrobial agents. With the exception of several new classes of drugs primarily targeting nosocomial infections, progress has been slow. While pharmaceutical companies continue to introduce new drugs, they are based on decade-old discoveries. While there is disagreement about what constitutes new classes of antibiotics, many experts suggest that the last truly new family of antimicrobials was discovered in 1987. This review summarizes the existing literature on antibiotic resistance in common bacterial and protozoal STIs. It also briefly discusses several of the most promising alternatives to current therapies, and further examines how advances in drug delivery, formulation, concentration, and timing are improving the efficacy of existing treatments. Finally, the paper discusses the current state of pharmaceutical development for multidrug-resistant STI.

  2. The capacity of black holes to transmit quantum information

    Energy Technology Data Exchange (ETDEWEB)

    Brádler, Kamil [Department of Astronomy and Physics, Saint Mary’s University,Halifax, Nova Scotia, B3H 3C3 (Canada); Adami, Christoph [Department of Physics and Astronomy, Michigan State University,East Lansing, MI 48824 (United States)

    2014-05-21

    We study the properties of the quantum information transmission channel that emerges from the quantum dynamics of particles interacting with a black hole horizon. We calculate the quantum channel capacity in two limiting cases where a single-letter capacity is known to exist: the limit of perfectly reflecting and perfectly absorbing black holes. We find that the perfectly reflecting black hole channel is closely related to the Unruh channel and that its capacity is non-vanishing, allowing for the perfect reconstruction of quantum information outside of the black hole horizon. We also find that the complementary channel (transmitting entanglement behind the horizon) is entanglement-breaking in this case, with vanishing capacity. We then calculate the quantum capacity of the black hole channel in the limit of a perfectly absorbing black hole and find that this capacity vanishes, while the capacity of the complementary channel is non-vanishing instead. Rather than inviting a new crisis for quantum physics, this finding instead is in accordance with the quantum no-cloning theorem, because it guarantees that there are no space-like surfaces that contain both the sender’s quantum state and the receiver’s reconstructed quantum state.

  3. A Multi-detection Assay for Malaria Transmitting Mosquitoes

    Science.gov (United States)

    Lee, Yoosook; Weakley, Allison M.; Nieman, Catelyn C.; Malvick, Julia; Lanzaro, Gregory C.

    2015-01-01

    The Anopheles gambiae species complex includes the major malaria transmitting mosquitoes in Africa. Because these species are of such medical importance, several traits are typically characterized using molecular assays to aid in epidemiological studies. These traits include species identification, insecticide resistance, parasite infection status, and host preference. Since populations of the Anopheles gambiae complex are morphologically indistinguishable, a polymerase chain reaction (PCR) is traditionally used to identify species. Once the species is known, several downstream assays are routinely performed to elucidate further characteristics. For instance, mutations known as KDR in a para gene confer resistance against DDT and pyrethroid insecticides. Additionally, enzyme-linked immunosorbent assays (ELISAs) or Plasmodium parasite DNA detection PCR assays are used to detect parasites present in mosquito tissues. Lastly, a combination of PCR and restriction enzyme digests can be used to elucidate host preference (e.g., human vs. animal blood) by screening the mosquito bloodmeal for host-specific DNA. We have developed a multi-detection assay (MDA) that combines all of the aforementioned assays into a single multiplex reaction genotyping 33SNPs for 96 or 384 samples at a time. Because the MDA includes multiple markers for species, Plasmodium detection, and host blood identification, the likelihood of generating false positives or negatives is greatly reduced from previous assays that include only one marker per trait. This robust and simple assay can detect these key mosquito traits cost-effectively and in a fraction of the time of existing assays. PMID:25867057

  4. The epidemiology of sexually transmitted infections in adolescents.

    Science.gov (United States)

    Risser, William L; Bortot, Andrea T; Benjamins, Laura J; Feldmann, Jennifer M; Barratt, Michelle S; Eissa, Mona A; Risser, Jan M H

    2005-07-01

    This article addresses the epidemiology of several common sexually transmitted infections (STIs) in adolescents. Chlamydia is a common occurrence in adolescents, more so than is gonorrhea, but both are of particular concern because they may cause pelvic inflammatory disease. Many experts recommend screening for chlamydia in sexually active adolescents, particularly females. Trichomonas vaginalis is significant as a marker for risk of contracting other STIs and because of its association with pregnancy complications and with increased risk of transmission of HIV. Genital herpes simplex virus (HSV) infection, which usually has been caused by HSV-2, is a common finding in adolescents, and it now is caused also by HSV-1 in some populations. Human papillomavirus (HPV), though widespread in adolescents, usually is a self-limited infection, and malignancy resulting from HPV is a rare occurrence in this age group. The least common of the diseases discussed below is syphilis, but a recent sharp increase in incidence has occurred in men who have sex with men.

  5. Sexually Transmitted Diseases and Travel: From Boudoir to Bordello.

    Science.gov (United States)

    Avery, Ann K; Zenilman, Jonathan M

    2015-10-01

    Travel has historically been an important risk factor for acquisition of sexually transmitted infections (STIs). Travel is often associated with a sense of adventure, periods of loneliness, and exploration away from one's home environment-which often form a milieu in which sexual activity can occur with new partners. Survey data clearly demonstrate that out-of-country travel is associated with recruitment of new sex partners and increased STI risk. Pretravel counseling to prevent STI risk is variable, and there is little evidence that it modifies risk behavior. Some travel occurs specifically for sexual purposes, such as the sexual tourism junkets to Southeast Asian destinations which became popular during the 1980s or the more recent rise in the popularity of circuit parties for men who have sex with men. Some travel situations pose particularly high risks. For example, military deployments and assignments to work camps such as those for oil extraction occur in the context of large groups of individuals of reproductive age, often predominantly males, exposed to high levels of stress in unfamiliar environments. Additionally, over the past decade, the Internet has dramatically changed the ability to identify sexual partners while traveling.

  6. Piezolectric transmitting and receiving systems for purposes of echosonography

    Science.gov (United States)

    Lypacewicz, Grazyna

    The purpose of this paper is to analyze piezoelectric transmitting and receiving systems mainly from the standpoint of application in the echosonographic instruments being developed in the Ultrasound Laboratory of the Institute of fundamental Technology Research of the Polish Academy of Sciences. Our own research was preceded by a discussion of equivalent circuits of piezoelectric transducers mentioned in references. The equivalent circuit was expanded to include electric parameters (compensation circuit, cables, feed conductors, resistances -shunting resistances, those of the transmitter and receiver) as well as mechanical and dielectric losses (according to Carlson and Brown). Both acoustic and electric parameters as well as relative values have been introduced to investigate the influence of individual parameters on the circuit performance. A fast Fourier transform and matrix calculation have been used to calculate the driving point function, transfer function, acoustic and electric pulses. It has been demonstrated that head parameters (compensation circuit, the thickness of the acoustic fitting layers) should be optimized for electric resonance frequency, which is a function of the conjugation factor K(sub t). the admittance curve has been shown to become symmetric, while its value is reduced to a minimum for optimal fitting layer thickness (lambda(sub e)/4). This led to the development of a method of layer thickness optimization in the course of polishing via the measurement of electric admittance.

  7. Renal allograft tuberculosis with infected lymphocele transmitted from the donor.

    Science.gov (United States)

    Al-Nesf, Maryam Ali; Al-Ani, Omar Isam; Al-Ani, Ahmed Abdul-Rahman; Rashed, Awad Hamed

    2014-03-01

    Transmission of tuberculosis (TB) from a donor through renal transplantation is a rare incident. We are reporting a 53-year-old Qatari woman diagnosed with renal allograft TB infection. The disease was confirmed by isolation of Mycobacterium tuberculosis from fluid from the lymphocele and demonstration of caseating granuloma in graft biopsy with acid-fast bacilli seen on Ziehl-Neelsen staining. The diagnosis was made quite early post-transplantation. The presence of the granuloma, which is unusual with patients on intensive immunosuppressant medications, suggests that transmission of the infection occurred from the donor rather than from the activation of latent infection. In reviewing the literature, we found ten case reports of TB in transplanted kidney with transmission of TB infection from the donor. The presence of TB in lymphocele in association with the infected transplant by TB, to the best of our knowledge, was reported only once in the literature. Our case had unfavorable outcome and ended by renal allograft nephrectomy and hemodialysis. We are presenting this case of TB infection of renal allograft and lymphocele diagnosed early post-transplantation transmitted from the donor and pertinent review from the literature.

  8. Performance of MC-CDMA Systems with Orthogonal Transmit Diversity over Rayleigh Fading Channel

    Institute of Scientific and Technical Information of China (English)

    樊凌涛; 李高志; 陈健

    2003-01-01

    Transmit diversity has been recently proposed to reduce the effects of fading channels in various wireless applications. Orthogonal transmit diersity (OTD) is one of the standardized techniques in 3G systems. In this paper, we apply orthogonal transmit diversity technique to multicarrier CDMA systems. Andlysis and simulation results show that performance benefits can be achieved compared with conventioal MC-CDMA systems in multipath fading channels.

  9. A cognitive behavioural intervention to reduce sexually transmitted infections among gay men: randomised trial

    OpenAIRE

    Imrie, J.; Stephenson, J R; Cowan, F. M.; Wanigaratne, S; Billington, A. J. P.; Copas, A. J.; French, L.; French, P D; Johnson, A. M.; Behav Intervention Gay Men Project

    2001-01-01

    Objective To determine the effectiveness of a brief cognitive behavioural intervention in reducing the incidence of sexually transmitted infections among gay men.Design Randomised controlled trial with 12 months' follow up.Setting Sexual health clinic in London.Participants 343 gay men with an acute sexually transmitted infection or who reported having had unprotected anal intercourse in the past year.Main outcome measures Number of new sexually transmitted infections diagnosed during follow ...

  10. Shadow imaging of geosynchronous satellites

    Science.gov (United States)

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite

  11. High-speed analog fiber optic links for satellite communication

    Science.gov (United States)

    Daryoush, A. S.; Herczfeld, P. R.; Kunath, R. R.

    1988-01-01

    Large-aperture phased array antennas operating at millimeter wave frequencies are designed for space-based communications and imaging. Array elements are comprised of active transmit/receive (T/R) modules which are linked to the central processing unit through a high-speed fiberoptic network. This paper demonstrates optical control of active modules for satellite communication at 24 GHz. An approach called T/R level data mixing, which utilizes fiberoptic transmission of a data signal to individual T/R modules to be upconverted by an optically synchronized local oscillator, is demonstrated at 24 GHz. A free-running HEMT oscillator, used as local oscillator at 24 GHz, is synchronized using indirect subharmonic optical injection locking over a locking range of 14 MHz. Results of data link performance over 500-1000 MHz is also reported in terms of gain-bandwidth, linearity and third-order intercept, sensitivity, and dynamic range.

  12. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    Science.gov (United States)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  13. CHINA RETRIEVES 19th RECOVERABLE SATELLITE

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China on Sept.25 recovered its 19th recoverable sci-tech experimental satellite 27 days after the satellite orbited in space. The satellite, which was launched on Aug.29 from the Jiuquan Satellite Launch Center in Gansu Province, northwest China, touched the ground at 7:55 a.m.on Sept.25. The satellite, atop a Long March 2C carrier rocket, is mainly for

  14. Lopsided Collections of Satellite Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    You might think that small satellite galaxies would be distributed evenly around their larger galactic hosts but local evidence suggests otherwise. Are satellite distributions lopsided throughout the universe?Satellites in the Local GroupThe distribution of the satellite galaxies orbiting Andromeda, our neighboring galaxy, is puzzling: 21 out of 27 ( 80%) of its satellites are on the side of Andromeda closest to us. In a similar fashion, 4 of the 11 brightest Milky Way satellites are stacked on the side closest to Andromeda.It seems to be the case, then, that satellites around our pair of galaxies preferentially occupy the space between the two galaxies. But is this behavior specific to the Local Group? Or is it commonplace throughout the universe? In a recent study, a team of scientists led by Noam Libeskind (Leibniz Institute for Astrophysics Potsdam, Germany) set out to answer this question.Properties of the galaxies included in the authors sample. Left: redshifts for galaxy pairs. Right: Number of satellite galaxies around hosts. [Adapted from Libeskind et al. 2016]Asymmetry at LargeLibeskind and collaborators tested whether this behavior is common by searching through Sloan Digital Sky Survey observations for galaxy pairs that are similar to the Milky Way/Andromeda pair. The resulting sample consists of 12,210 pairs of galaxies, which have 46,043 potential satellites among them. The team then performed statistical tests on these observations to quantify the anisotropic distribution of the satellites around the host galaxies.Libeskind and collaborators find that roughly 8% more galaxies are seen within a 15 angle facing the other galaxy of a pair than would be expected in a uniform distribution. The odds that this asymmetric behavior is randomly produced, they show, are lower than 1 in 10 million indicating that the lopsidedness of satellites around galaxies in pairs is a real effect and occurs beyond just the Local Group.Caution for ModelingProbability that

  15. Influence of beam wander on bit-error rate in a ground-to-satellite laser uplink communication system.

    Science.gov (United States)

    Ma, Jing; Jiang, Yijun; Tan, Liying; Yu, Siyuan; Du, Wenhe

    2008-11-15

    Based on weak fluctuation theory and the beam-wander model, the bit-error rate of a ground-to-satellite laser uplink communication system is analyzed, in comparison with the condition in which beam wander is not taken into account. Considering the combined effect of scintillation and beam wander, optimum divergence angle and transmitter beam radius for a communication system are researched. Numerical results show that both of them increase with the increment of total link margin and transmitted wavelength. This work can benefit the ground-to-satellite laser uplink communication system design.

  16. Geometric Aspects of Ground Augmentation of Satellite Networks for the Needs of Deformation Monitoring

    Science.gov (United States)

    Protaziuk, Elżbieta

    2016-06-01

    Satellite measurements become competitive in many tasks of engineering surveys, however, in many requiring applications possibilities to apply such solutions are still limited. The possibility to widely apply satellite technologies for displacements measurements is related with new challenges; the most important of them relate to increasing requirements concerning the accuracy, reliability and continuity of results of position determination. One of the solutions is a ground augmentation of satellite network, which intention is to improve precision of positioning, ensure comparable accuracy of coordinates and reduce precision fluctuations over time. The need for augmentation of GNSS is particularly significant in situations: where the visibility of satellites is poor because of terrain obstacles, when the determined position is not precise enough or a satellites constellation does not allow for reliable positioning. Ground based source/sources of satellite signal placed at a ground, called pseudosatellites, or pseudolites were intensively investigated during the last two decades and finally were developed into groundbased, time-synchronized transceivers, that can transmit and receive a proprietary positioning signal. The paper presents geometric aspects of the ground based augmentation of the satellite networks using various quality measures of positioning geometry, which depends on access to the constellation of satellites and the conditions of the observation environment. The issue of minimizing these measures is the key problem that allows to obtain the position with high accuracy. For this purpose, the use of an error ellipsoid is proposed and compared with an error ellipse. The paper also describes the results of preliminary accuracy analysis obtained at test area and a comparison of various measures of the quality of positioning geometry.

  17. Jupiter small satellite montage

    Science.gov (United States)

    2000-01-01

    A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo 'prime mission'--and was about to embark on a successful two-year extension, called the Galileo Europa Mission. The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views; this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter. The next two images show the moon Amalthea; they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that 'leads' as Amalthea moves in its orbit around Jupiter. This image looks 'noisy' because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent 'spots' of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis. In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles); Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles); Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles); Amalthea on November 7, 1997 at a

  18. Weather Satellite Enterprise Information Chain

    Science.gov (United States)

    Jamilkowski, M. L.; Grant, K. D.; Miller, S. W.; Cochran, S.

    2015-12-01

    NOAA & NASA are acquiring the next-generation civilian operational weather satellite: Joint Polar Satellite System (JPSS). Contributing the afternoon orbit & ground system (GS) to replace current NOAA POES Satellites, its sensors will collect meteorological, oceanographic & climatological data. The JPSS Common Ground System (CGS), consisting of C3 and IDP segments, is developed by Raytheon. It now flies the Suomi National Polar-orbiting Partnership (S-NPP) satellite, transferring data between ground facilities, processing them into environmental products for NOAA weather centers, and expanding to support JPSS-1 in 2017. As a multi-mission system, CGS provides combinations of C3, data processing, and product delivery for numerous NASA, NOAA, DoD and international missions.The CGS provides a wide range of support to a number of missions: Command and control and mission management for the S-NPP mission today, expanding this support to the JPSS-1 satellite mission in 2017 Data acquisition for S-NPP, the JAXA's Global Change Observation Mission - Water (GCOM-W1), POES, and the Defense Meteorological Satellite Program (DMSP) and Coriolis/WindSat for the DoD Data routing over a global fiber network for S-NPP, JPSS-1, GCOM-W1, POES, DMSP, Coriolis/WindSat, NASA EOS missions, MetOp for EUMETSAT and the National Science Foundation Environmental data processing and distribution for S-NPP, GCOM-W1 and JPSS-1 The CGS plays a key role in facilitating the movement and value-added enhancement of data all the way from satellite-based sensor data to delivery to the consumers who generate forecasts and produce watches and warnings. This presentation will discuss the information flow from sensors, through data routing and processing, and finally to product delivery. It will highlight how advances in architecture developed through lessons learned from S-NPP and implemented for JPSS-1 will increase data availability and reduce latency for end user applications.

  19. Remote, mobile telemedicine: the satellite transmission of medical data from Mount Logan.

    Science.gov (United States)

    Otto, C; Pipe, A

    1997-01-01

    The purpose of this investigation was to demonstrate the potential of remote, mobile telemedicine during a four-week, high-altitude mountaineering expedition to Mount Logan, Canada's highest summit. Using a mobile satellite terminal and a laptop computer (both powered by a photovoltaic solar panel), ECG tracings and blood pressure measurements, in addition to colour images, short-segment video and audio clips were transmitted during the course of the ascent. The data were transmitted via a mobile communications satellite to a ground station in Ottawa, a distance of over 4000 km. The data were then transferred to the public switched data network and delivered to the University of Ottawa Heart Institute for analysis. Similarly, data were transmitted from the ground station to the expedition team on Mount Logan throughout the ascent. Using this technique, medical diagnosis and emergency care can be facilitated in extreme and isolated locations lacking a telecommunications infrastructure. Such technology has applications in developing countries, disaster response efforts, remote civilian and military operations, and in space operations.

  20. Pop-up archival transmitting (PAT) tags: A method to investigate the migration and behavior of Pacific halibut (Hippoglossus stenolepis) in the Gulf of Alaska

    Science.gov (United States)

    Seitz, Andrew C.; Wilson, Derek; Norcross, Brenda L.; Nielsen, Jennifer L.

    2003-01-01

    Pop-up archival transmitting (PAT) tags provide a fisheries-independent method of collecting environmental preference data (depth and ambient water temperature) and migration distance. In this study, we evaluate the use of pop-up archival transmitting tags as a method to investigate demersal fish. We report the results from eight pop-up archival transmitting tagged Pacific halibut Hippoglossus stenolepis (from 107 to 165 cm FL) that were released in and around Resurrection Bay, Alaska. Commercial fishermen recovered three tags, while five tags transmitted data to Argos satellites. Horizontal migration was not consistent among fish as four Pacific halibut remained in the vicinity of release while the other four traveled up to 358 km from the release site. Vertical movement was not consistent among fish or over time; however, they spent most of their time at depths of 150 to 350 m. The minimum and maximum depths reached by any of the Pacific halibut were 2 m and 502 m, respectively. The fish preferred water temperatures of approximately 6°C, but experienced temperatures between 4.3 and 12.2°C. Light attenuation with depth prevented geolocation software and light sensing hardware from accurately estimating geoposition for the majority of days. The methods, adapted from investigations on large pelagic fish, proved to be effective for studying Pacific halibut in the northern Gulf of Alaska. PAT tags allowed us to obtain high accuracy locations of the fish at the end of the tag deployments as well as preliminary data to identify approximate seasonal locations and to characterize their depth and temperature characteristics. By using PAT tags, we will be able to ensure tag returns during the winter season (which is closed to fishing) and gain valuable biological information even if fish migrate large distances or to unexpected locations.

  1. Stream Gauges and Satellite Measurements

    Science.gov (United States)

    Alsdorf, D. E.

    2010-12-01

    Satellite measurements should not be viewed as a replacement for stream gauges. However, occasionally it is suggested that because satellite-based measurements can provide river discharge, a motivation for satellite approaches is an increasing lack of stream gauges. This is an argument for more stream gauges, but not necessarily for satellite measurements. Rather, in-situ and spaceborne methods of estimating discharge are complementary. Stream gauges provide frequent measurements at one point in the river reach whereas satellites have the potential to measure throughout all reaches but at orbital repeat intervals of days to weeks. The Surface Water and Ocean Topography satellite mission (SWOT) is an opportunity to further develop these complements. The motivation for SWOT, and indeed for any satellite based method of estimating discharge, should not be as a replacement for stream gauges. Scientific and application uses should motivate the measurements. For example, understanding floods with their dynamic water surfaces are best sampled from remote platforms that provide water surface elevations throughout the floodwave. As another example, today’s water and energy balance models are giving outputs at increasing spatial resolution and are making use of water surface elevations throughout the modeled basin. These models require a similar resolution in the calibrating and validating observations. We should also be aware of practical limitations. In addition to providing spatially distributed hydrodynamic measurements on rivers, SWOT will be able to measure storage changes in the estimated 30 million lakes in the world that are larger than a hectare. Knowing the storage changes in these lakes is especially important in certain regions such as the Arctic but gauging even a small fraction of these is impractical. Another motivator for satellite methods is that even in the presence of stream gauges, discharge data is not always well shared throughout all countries

  2. Multiplex PCR testing for nine different sexually transmitted infections.

    Science.gov (United States)

    Kriesel, John D; Bhatia, Amiteshwar S; Barrus, Cammie; Vaughn, Mike; Gardner, Jordan; Crisp, Robert J

    2016-12-01

    Current sexually transmitted infection (STI) testing is not optimal due to delays in reporting or missed diagnoses due to a lack of comprehensive testing. The FilmArray® (BioFire Diagnostics, LLC, Salt Lake City, Utah) is a user-friendly, fully automated, multiplex PCR system that is being developed for rapid point-of-care use. A research-use-only STI panel including multiple PCR primer sets for each organism was designed to detect Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, Trichomonas vaginalis, Mycoplasma genitalium, Ureaplasma urealyticum, Haemophilus ducreyi, and herpes simplex virus (HSV) types 1 and 2. Standard clinical testing included Gram stain, nucleic acid amplification, wet mount examination, herpes simplex virus culture, and syphilis IgG. Standard clinical tests were not available for all the organisms tested by the FilmArray STI panel. Two hundred and ninety-five clinical specimens from 190 subjects were directly compared to standard testing. Urine (n = 146), urethral/cervical swabs (31), oral swabs (60), rectal swabs (43), and ulcer swabs (15) were tested. Among the tested samples, FilmArray detected C. trachomatis in 39 (13%), N. gonorrhoeae in 20 (7%), T. vaginalis in nine (3%), HSV 1 in five (2%), HSV 2 in five (2%), U. urealyticum in 36 (12%), M. genitalium in eight (3%), and T. pallidum in 11 (4%). Concordance between the FilmArray STI panel and standard nucleic acid amplification testing for C. trachomatis was 98% and for N. gonorrhoeae was 97%. Multiplex PCR STI testing has the potential to improve public health by providing rapid, sensitive, and reliable results within the clinic or nearby laboratory.

  3. Screening for sexually transmitted infection pathogens in semen samples.

    Science.gov (United States)

    Peeling, Rw; Embree, J

    2005-03-01

    The transmission of sexually transmitted infection (STI) pathogens from an infected donor to the recipient of a semen donation in assisted conception may result not only in acute infection but also in long-term reproductive complications or adverse outcomes of pregnancy, including infection of the offspring. Screening for bacterial STI pathogens, Chlamydia trachomatis and Neisseria gonorrhoeae is strongly recommended because these pathogens can cause serious reproductive complications in the recipients of semen donations and infection in their offspring. Screening for these pathogens should be performed using the most sensitive methods, such as nucleic acid amplified tests. False-negative results due to inhibitory substances in the semen sample should be monitored using amplification controls. Where specimen transport is not a problem and culture facilities are available, N gonorrhoeae can also be detected by culture. Laboratories performing screening should subscribe to proficiency programs and have strict quality controls. Although Trichomonas vaginalis, group B streptococcus and genital mycoplasmas have been associated with adverse outcomes of pregnancy, the frequent finding of these organisms in healthy individuals brings into question the validity of mandatory inclusion of these organisms in the screening panel. Although viral STI pathogens and Treponema pallidum - the causative agent of syphilis - may be detected in semen, their presence may be more sensitively detected through antibody testing of the donor. Screening donors for HIV, hepatitis B and syphilis by serology is uniformly recommended in all of the guidelines, but the value of screening either donors or semen samples for cytomegalovirus, herpes simplex viruses and human papilloma viruses is less clear.

  4. Sexually Transmitted Infections (STIs among young adult in Italy

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    Maria Cristina Salfa

    2010-12-01

    Full Text Available Sexually transmitted infections (STIs include a large group of widespread infectious diseases, which may cause acute symptoms, chronic infections and severe long term complications.The control and prevention of these infections are public health priorities for several reasons: • the large number of people that acquire an STI per year; • the major proportion of asymptomatic infected individuals; • the high circulation in patients with sexual risk behavior (young adults, pluripartner, men who have sex with men, foreigners, commercial sex workers; • increased biological susceptibility of some subjects, such as young adults (immature genital tissues and more receptive to pathogens, women (genital apparatus more complex and extended in which pathogens are more likely to settle, or individuals carrying states of severe immunodeficiency; • the serious complications in the event of failure or incorrect diagnosis and treatment (chronic disease, infertility, oncogenic transformation, synergy with HIV infection; • the possibility of preventing and treating many of these infections. Therefore, recent guidelines from international agencies have recommended countries from the European Union to improve epidemiological STI surveillance systems in order to standardize data collection to facilitate their comparability between different geographical areas and to improve the information flow for faster tracking of the impact; furthermore, to extend surveillance to widespread, but often asymptomatic, disease (e.g. Chlamydia trachomatis, to conduct behavioural surveillance in patients with STIs, to increase public awareness of the role of STIs in the transmission/acquisition of HIV, and to increase the commitment of institutions in the prevention and control of STIs.

  5. Screening for Sexually Transmitted Infection Pathogens in Semen Samples

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    RW Peeling

    2005-01-01

    Full Text Available The transmission of sexually transmitted infection (STI pathogens from an infected donor to the recipient of a semen donation in assisted conception may result not only in acute infection but also in long-term reproductive complications or adverse outcomes of pregnancy, including infection of the offspring. Screening for bacterial STI pathogens, Chlamydia trachomatis and Neisseria gonorrhoeae is strongly recommended because these pathogens can cause serious reproductive complications in the recipients of semen donations and infection in their offspring. Screening for these pathogens should be performed using the most sensitive methods, such as nucleic acid amplified tests. False-negative results due to inhibitory substances in the semen sample should be monitored using amplification controls. Where specimen transport is not a problem and culture facilities are available, N gonorrhoeae can also be detected by culture. Laboratories performing screening should subscribe to proficiency programs and have strict quality controls. Although Trichomonas vaginalis, group B streptococcus and genital mycoplasmas have been associated with adverse outcomes of pregnancy, the frequent finding of these organisms in healthy individuals brings into question the validity of mandatory inclusion of these organisms in the screening panel. Although viral STI pathogens and Treponema pallidum -- the causative agent of syphilis -- may be detected in semen, their presence may be more sensitively detected through antibody testing of the donor. Screening donors for HIV, hepatitis B and syphilis by serology is uniformly recommended in all of the guidelines, but the value of screening either donors or semen samples for cytomegalovirus, herpes simplex viruses and human papilloma viruses is less clear.

  6. Sexually transmitted infections among HIV-1-discordant couples.

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    Brandon L Guthrie

    Full Text Available INTRODUCTION: More new HIV-1 infections occur within stable HIV-1-discordant couples than in any other group in Africa, and sexually transmitted infections (STIs may increase transmission risk among discordant couples, accounting for a large proportion of new HIV-1 infections. Understanding correlates of STIs among discordant couples will aid in optimizing interventions to prevent HIV-1 transmission in these couples. METHODS: HIV-1-discordant couples in which HIV-1-infected partners were HSV-2-seropositive were tested for syphilis, chlamydia, gonorrhea, and trichomoniasis, and HIV-1-uninfected partners were tested for HSV-2. We assessed sociodemographic, behavioral, and biological correlates of a current STI. RESULTS: Of 416 couples enrolled, 16% were affected by a treatable STI, and among these both partners were infected in 17% of couples. A treatable STI was found in 46 (11% females and 30 (7% males. The most prevalent infections were trichomoniasis (5.9% and syphilis (2.6%. Participants were 5.9-fold more likely to have an STI if their partner had an STI (P<0.01, and STIs were more common among those reporting any unprotected sex (OR = 2.43; P<0.01 and those with low education (OR = 3.00; P<0.01. Among HIV-1-uninfected participants with an HSV-2-seropositive partner, females were significantly more likely to be HSV-2-seropositive than males (78% versus 50%, P<0.01. CONCLUSIONS: Treatable STIs were common among HIV-1-discordant couples and the majority of couples affected by an STI were discordant for the STI, with relatively high HSV-2 discordance. Awareness of STI correlates and treatment of both partners may reduce HIV-1 transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00194519.

  7. An overview on sexually transmitted infections in Iran

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    Roksana Janghorban

    2016-03-01

    Full Text Available Sexually transmitted infections (STIs cause a large proportion of the global burden of ill-health, disability, and death. This paper reviews the status of STIs in Iran in the three groups of infections are caused by bacterial, viral, and parasitic pathogens and then focuses on human immunodeficiency virus (HIV infection. This review was carried out in the period of 1977-2015 by searching in PubMed, Scopus, Embase, Web of sciences, Google scholar, the Iranian databases such as MagIran, IranMedex and SID using relevant English and Persian key words. Articles, reports, fact sheets, and official publications of World Health Organization (WHO, the United Nations Program on HIV and AIDS (UNAIDS, The United Nations Childrens Fund (UNICEF, and the Ministry of Health and Medical Education (MOHME of Iran were reviewed. Data on the prevalence of STIs in Iran is sparse with very limited generalizability to the general population. But studies show that these infections are concentrated in high risk sub-groups of the population. Iran has a low national HIV prevalence, but an increased prevalence among people who inject drugs, shifting the country from low prevalence to a concentrated prevalence. It seems that the more improvement of HIV/AIDS prevention, care and treatment programs in Iran need to more attention toward controlling HIV/AIDS through sexual health, proper linkage among HIV/AIDS, STIs, and SRH programs, reduction of stigma and discrimination toward people living with HIV/AIDS, and increase to access at risk populations. [Int J Reprod Contracept Obstet Gynecol 2016; 5(3.000: 585-595

  8. Rotation Elastogram Estimation Using Synthetic Transmit Aperture Technique.

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    B, Lokesh; Chintada, Bhaskara Rao; Thittai, Arun Kumar

    2017-01-01

    It is well-documented in literature that benign breast lesions, such as fibroadenomas, are loosely bonded to their surrounding tissue and tend to slip under a small quasi-static compression, whereas malignant lesions being firmly bonded to their surrounding tissue do not slip. Recent developments in quasi-static ultrasound elastography have shown that an image of the axial-shear strain distribution can provide information about the bonding condition at the lesion-surrounding tissue boundary. Further studies analyzing the axial-shear strain elastograms revealed that nonzero axial-shear strain values appear inside the lesion, referred to as fill-in, only when a lesion is loosely bonded and asymmetrically oriented to the axis of compression. It was argued that the fill-in observed in axial-shear strain elastogram is a surrogate of the actual rigid-body rotation undergone by such a benign lesion due to slip boundary condition. However, it may be useful and perhaps easy to interpret, if the actual rigid-body rotation of the lesion can itself be visualized directly. To estimate this rotation tensor and its spatial distribution map (called a Rotation Elastogram [RE]), it would be necessary to improve the quality of lateral displacement estimates. Recently, it has been shown in the context of Non-Invasive Vascular Elastography (NIVE) that the Synthetic Transmit Aperture (STA) technique can be adapted for elastography to improve the lateral displacement estimates. Therefore, the focus of this work was to investigate the feasibility of employing the STA technique to improve the lateral displacement estimation and assess the resulting improvement in the RE quality. This investigation was done using both simulation and experimental studies. The image quality metric of contrast-to-noise ratio (CNR) was used to evaluate the quality of rotation elastograms. The results demonstrate that the contrast appeared in RE only in the case of loosely bonded inclusion, and the quality of RE

  9. Identifying outbreaks of sexually transmitted infection: who cares?

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    Evans Meirion R

    2006-10-01

    Full Text Available Abstract Background Current routine surveillance schemes for sexually transmitted infections (STIs in the United Kingdom (UK are not designed for outbreak identification. Recognising STI outbreaks, therefore, depends almost entirely on the alertness of health professionals. The objective of this study was to explore health professionals' knowledge of, and attitudes towards, identification and investigation of STI outbreaks in Wales. Methods We conducted a cross-sectional survey in Wales in June 2005, and sent a questionnaire to consultants of genitourinary medicine (GUM, n = 11, a consultant microbiologist from each laboratory (n = 14, all consultants in communicable disease control (n = 5, and to epidemiologists of the National Public Health Service (n = 4. Results 26 (76% of 34 survey recipients responded. Of these, 17 (65% ranked the investigation of STI outbreaks as important or very important, and 19 (73% perceived participation in the investigation of an STI outbreak as part of their responsibility. Only six (25% respondents had actively searched their computer system or patient records for a possible STI outbreak in the previous twelve months, and 15 (63% had never looked for an outbreak. Of seven GUM physicians who said they had identified at least one STI outbreak, three had never informed public health authorities. Conclusion Prompt identification and coordinated investigation of outbreaks, usually through a multidisciplinary outbreak control team, is central to the control of many infectious diseases. This does not appear to be the case for STIs, which we believe represents a lost opportunity to reduce transmission. Besides improved surveillance methods, a change in culture towards STI outbreaks is needed among health professionals in Wales.

  10. Frequency of sexually transmitted diseases and main methodological implications

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    Zaleida Napoli

    2013-08-01

    Full Text Available Background. High risk Human Papillomavirus (HR-HPV persistence is the most important cervical cancer risk factor, while Chlamydia trachomatis (CT, Neisseria gonorrhoeae (NG, Mycoplasma hominis (MH, Mycoplasma genitalium(MG, Ureaplasma urealyticum (UU and parvum (UP are sexually transmitted diseases (STDs causing infertility, pregnancy complication, lung problems in newborns. Methods. 135 urine, 135 urethral swabs, 553 cervical swabs, 110 seminal fluids and 1440 Thin Prep, were tested with culture methods, Real-Time PCR (RT-PCR and multiplex SYBR Green PCR-endpoint to detect STDs. PCR- endpoint was performed to detect HPV. Results. Culture methods showed the lowest sensitivity: for MH it was only 24% (compared to RT-PCR. UP/UU were the most frequent pathogens (13% with culture, 29% with PCR-endpoint, 41,67% with RT-PCR. Turn Around Time was respectively: 48h, 6h and 2h. RT-PCR cervical frequencies for CT, MH, MG, UU, UP were: 5.42%, 11.03%, 1.81%, 11.21% and 35.08%. HPV positivity in primary and secondary screening was 17.33% and 51.14%. Highes t positivity age group was: 23-32 years for CT (17%, and 18-27 years for HPV (33%. Conclusions. RT-PCR is more sensitive, faster, less expensive than other molecular tests like PCR-endpoint and microarrays. It allows more efficient laboratory organization: pre-analytical phase is more automated and enable the implementation of further diagnostic tests for pathologies that need rapid identification, such as meningitidis and sepsis, with reduced human and instrumental resource. Regarding STDs screening, it should be performed in women: for CT at least up to 27 years; for HPV between 35-50 years, since persisting HR-HPV infection is responsible of high-grade lesions.

  11. Differential Persistence of Transmitted HIV-1 Drug Resistance Mutation Classes

    Science.gov (United States)

    Jain, Vivek; Sucupira, Maria C.; Bacchetti, Peter; Hartogensis, Wendy; Diaz, Ricardo S.; Kallas, Esper G.; Janini, Luiz M.; Liegler, Teri; Pilcher, Christopher D.; Grant, Robert M.; Cortes, Rodrigo; Deeks, Steven G.

    2011-01-01

    Background. Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) mutations can become replaced over time by emerging wild-type viral variants with improved fitness. The impact of class-specific mutations on this rate of mutation replacement is uncertain. Methods. We studied participants with acute and/or early HIV infection and TDR in 2 cohorts (San Francisco, California, and São Paulo, Brazil). We followed baseline mutations longitudinally and compared replacement rates between mutation classes with use of a parametric proportional hazards model. Results. Among 75 individuals with 195 TDR mutations, M184V/I became undetectable markedly faster than did nonnucleoside reverse-transcriptase inhibitor (NNRTI) mutations (hazard ratio, 77.5; 95% confidence interval [CI], 14.7–408.2; P < .0001), while protease inhibitor and NNRTI replacement rates were similar. Higher plasma HIV-1 RNA level predicted faster mutation replacement, but this was not statistically significant (hazard ratio, 1.71 log10 copies/mL; 95% CI, .90–3.25 log10 copies/mL; P = .11). We found substantial person-to-person variability in mutation replacement rates not accounted for by viral load or mutation class (P < .0001). Conclusions. The rapid replacement of M184V/I mutations is consistent with known fitness costs. The long-term persistence of NNRTI and protease inhibitor mutations suggests a risk for person-to-person propagation. Host and/or viral factors not accounted for by viral load or mutation class are likely influencing mutation replacement and warrant further study. PMID:21451005

  12. Using URIs to effectively transmit sensor data and metadata

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    Kokkinaki, Alexandra; Buck, Justin; Darroch, Louise; Gardner, Thomas

    2017-04-01

    Autonomous ocean observation is massively increasing the number of sensors in the ocean. Accordingly, the continuing increase in datasets produced, makes selecting sensors that are fit for purpose a growing challenge. Decision making on selecting quality sensor data, is based on the sensor's metadata, i.e. manufacturer specifications, history of calibrations etc. The Open Geospatial Consortium (OGC) has developed the Sensor Web Enablement (SWE) standards to facilitate integration and interoperability of sensor data and metadata. The World Wide Web Consortium (W3C) Semantic Web technologies enable machine comprehensibility promoting sophisticated linking and processing of data published on the web. Linking the sensor's data and metadata according to the above-mentioned standards can yield practical difficulties, because of internal hardware bandwidth restrictions and a requirement to constrain data transmission costs. Our approach addresses these practical difficulties by uniquely identifying sensor and platform models and instances through URIs, which resolve via content negotiation to either OGC's sensor meta language, sensorML or W3C's Linked Data. Data transmitted by a sensor incorporate the sensor's unique URI to refer to its metadata. Sensor and platform model URIs and descriptions are created and hosted by the British Oceanographic Data Centre (BODC) linked systems service. The sensor owner creates the sensor and platform instance URIs prior and during sensor deployment, through an updatable web form, the Sensor Instance Form (SIF). SIF enables model and instance URI association but also platform and sensor linking. The use of URIs, which are dynamically generated through the SIF, offers both practical and economical benefits to the implementation of SWE and Linked Data standards in near real time systems. Data can be linked to metadata dynamically in-situ while saving on the costs associated to the transmission of long metadata descriptions. The transmission

  13. Evolution of the apomixis transmitting chromosome in Pennisetum

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    Yamada-Akiyama Hitomi

    2011-10-01

    Full Text Available Abstract Background Apomixis is an intriguing trait in plants that results in maternal clones through seed reproduction. Apomixis is an elusive, but potentially revolutionary, trait for plant breeding and hybrid seed production. Recent studies arguing that apomicts are not evolutionary dead ends have generated further interest in the evolution of asexual flowering plants. Results In the present study, we investigate karyotypic variation in a single chromosome responsible for transmitting apomixis, the Apospory-Specific Genomic Region carrier chromosome, in relation to species phylogeny in the genera Pennisetum and Cenchrus. A 1 kb region from the 3' end of the ndhF gene and a 900 bp region from trnL-F were sequenced from 12 apomictic and eight sexual species in the genus Pennisetum and allied genus Cenchrus. An 800 bp region from the Apospory-Specific Genomic Region also was sequenced from the 12 apomicts. Molecular cytological analysis was conducted in sixteen Pennisetum and two Cenchrus species. Our results indicate that the Apospory-Specific Genomic Region is shared by all apomictic species while it is absent from all sexual species or cytotypes. Contrary to our previous observations in Pennisetum squamulatum and Cenchrus ciliaris, retrotransposon sequences of the Opie-2-like family were not closely associated with the Apospory-Specific Genomic Region in all apomictic species, suggesting that they may have been accumulated after the Apospory-Specific Genomic Region originated. Conclusions Given that phylogenetic analysis merged Cenchrus and newly investigated Pennisetum species into a single clade containing a terminal cluster of Cenchrus apomicts, the presumed monophyletic origin of Cenchrus is supported. The Apospory-Specific Genomic Region likely preceded speciation in Cenchrus and its lateral transfer through hybridization and subsequent chromosome repatterning may have contributed to further speciation in the two genera.

  14. A surveillance model for sexually transmitted infections in India

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    Partha Haldar

    2015-01-01

    Full Text Available The strategy for prevention and control of sexually transmitted infections (STIs in India is based on syndromic case management delivered through designated STI/reproductive tract infection (RTI centers (DSRCs situated in medical colleges, district hospitals, and STI-clinics of targeted interventions programs. Laboratory tests for enhanced syndromic management are available at some sites. To ensure country-level planning and effective local implementation of STI services, reliable and consistent epidemiologic information is required on the distribution of STI cases, rate and trends of newly acquired infections, and STI prevalence in specific population groups. The present STI management information system is inadequate to meet these requirements because it is based on syndromic data and limited laboratory investigations on STIs reported passively by DSRCs and laboratories. Geographically representative information on the etiology of STI syndromes and antimicrobial susceptibility of STI pathogens although essential for optimizing available treatment options, is deficient. Surveillance must provide high quality information on: (a prevalence of STIs such as syphilis, trichomoniasis, gonorrhea, and chlamydia among high-risk groups; syphilis in the general population and pregnant antenatal women; (b demographic characteristics such as age, sex, new/recurrent episode, and type of syndromically diagnosed STI cases; (c proportion of acute infections such as urethral discharge (UD in men and nonherpetic genital ulcer disease (GUD in men and women; (d etiology of STI syndromes; and (e gonococcal antimicrobial susceptibility. We describe here a framework for an STI sentinel surveillance system in India, building on the existing STI reporting systems and infrastructure, an overview of the components of the proposed surveillance system, and operational challenges in its implementation.

  15. [Sexually transmitted infections among transgender individuals and other sexual identities].

    Science.gov (United States)

    Toibaro, Javier J; Ebensrtejin, Juan E; Parlante, Angel; Burgoa, Patricia; Freyre, Alejandro; Romero, Marcela; Losso, Marcelo H

    2009-01-01

    Few data are available regarding the prevalence of sexually transmitted infections (STI), including HIV-1 infection, and risk behaviors of transgender individuals. Previous reports indicate that this community has a high prevalence of HIV and STIs. Our objective was to compare the prevalence of HIV-1 infection, STI and risk behaviors of transgender people versus non transgender people. We used a cross sectional design study. Patients who received services at our testing site between November 2002 and April 2006, and provided written informed consent, were included in the analysis. Socio-demographic data, sexual behaviour, recreational drug use, condom use, concurrent or previous STI and HIV-1 infection diagnosis and partner serologic status, were collected. We used descriptive statistics and chi 2 for comparisons of proportions. In the period of the study, 105 transgender individuals were identified in a population of 4118 patients tested. The prevalence of HIV infection in the transgender group was 27.6% (29/105), while in the non transgender group was 6.2% (247/4013) p:0.0000. Low level of formal instruction, alcohol consumption, drug abuse, previous history of STI and sex work (100% transgenders and 2.3% of non-transgenders) were significantly more frequent in the transgender. The referred correct use of condom was similar in both groups. The prevalence of syphilis was 42.3% in transgender group and 18.1% in non-transgender individuals. These data show that this population has a very high prevalence of HIV-1 and STI. This information could be instrumental to design targets for intensive HIV prevention strategies in this particular high risk population.

  16. Chartering Launchers for Small Satellites

    Science.gov (United States)

    Hernandez, Daniel

    The question of how to launch small satellites has been solved over the years by the larger launchers offering small satellites the possibility of piggy-backing. Specific fixtures have been developed and commercialized: Arianespace developed the ASAP interface, the USAF studied ESPA, NASA has promoted Shuttle launch possibilities, Russian authorities and companies have been able to find solutions with many different launchers... It is fair to say that most launcher suppliers have worked hard and finally often been able to find solutions to launch most small satellites into orbit. It is also true, however, that most of these small satellites were technology demonstration missions capable of accepting a wide range of orbit and launch characteristics: orbit altitude and inclination, launch date, etc. In some cases the small satellite missions required a well-defined type of orbit and have therefore been obliged to hire a small launcher on which they were the prime passenger. In our paper we would like to propose an additional solution to all these possibilities: launchers could plan well in advance (for example about 3 years), trips to precisely defined orbits to allow potential passengers to organize themselves and be ready on the D-Day. On the scheduled date the chartered launcher goes to the stated orbit while on another date, another chartered launcher goes to another orbit. The idea is to organize departures for space like trains or airplanes leaving on known schedules for known destinations.

  17. Low Earth orbit communications satellite

    Science.gov (United States)

    Moroney, D.; Lashbrook, D.; Mckibben, B.; Gardener, N.; Rivers, T.; Nottingham, G.; Golden, B.; Barfield, B.; Bruening, J.; Wood, D.

    1992-01-01

    A current thrust in satellite communication systems considers a low-Earth orbiting constellations of satellites for continuous global coverage. Conceptual design studies have been done at the time of this design project by LORAL Aerospace Corporation under the program name GLOBALSTAR and by Motorola under their IRIDIUM program. This design project concentrates on the spacecraft design of the GLOBALSTAR low-Earth orbiting communication system. Overview information on the program was gained through the Federal Communications Commission licensing request. The GLOBALSTAR system consists of 48 operational satellites positioned in a Walker Delta pattern providing global coverage and redundancy. The operational orbit is 1389 km (750 nmi) altitude with eight planes of six satellites each. The orbital planes are spaced 45 deg., and the spacecraft are separated by 60 deg. within the plane. A Delta 2 launch vehicle is used to carry six spacecraft for orbit establishment. Once in orbit, the spacecraft will utilize code-division multiple access (spread spectrum modulation) for digital relay, voice, and radio determination satellite services (RDSS) yielding position determination with accuracy up to 200 meters.

  18. Satellite Tracking Astrometric Network (STAN)

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    Vecchiato, Alberto; Gai, Mario

    2015-08-01

    The possibility of precise orbit tracking and determination of different types of satellites has been explored for at least some 25 years (Arimoto et al., 1990). Proposals in this sense made use mainly of astrometric observations, but multiple tracking techniques combining transfer and laser ranging was also suggested (Guo et al., 2009; Montojo et al., 2011), with different requirements and performances ranging from $\\sim100$~m to tenths of meters.In this work we explore the possible improvements and a novel implementation of a technique relying on large angle, high precision astrometry from ground for the determination of satellite orbits. The concept is based on combined observation of geostationary satellites and other near-Earth space objects from two or more telescopes, applying the triangulation principle over widely separated regions of the sky. An accuracy of a few $10^{-2}$~m can be attained with 1-meter-class telescopes and a field of vied of some arcminutes.We discuss the feasibility of the technique, some of the implementation aspects, and the limitations imposed by atmospheric turbulence. The potential benefits for satellite orbit control and navigation systems are presented, depending on the number and position of the contributing telescopes.We also discuss the possibility that, by reversing the roles of stars and satellites, the same kind of observations can be used for verification and maintenance of astrometric catalogs.

  19. Orbit Determination Using Satellite-to-Satellite Tracking Data

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Satellite-to-Satellite Tracking (SST) data can be used to determine the orbits of spacecraft in two ways. One is combined orbit determination, which combines SST data with ground-based tracking data and exploits the enhanced tracking geometry. The other is the autonomous orbit determination, which uses only SST. The latter only fits some particular circumstances since it suffers the rank defect problem in other circumstances. The proof of this statement is presented. The na ture of the problem is also investigated in order to find an effective solution. Several methods of solution are discussed. The feasibility of the methods is demonstrated by their apphcation to a simulation.

  20. Performance of a 16-ary DEQAM modem employing a baseband or RF predistorter over a regenerative satellite link

    Science.gov (United States)

    Cheung, S. W.; Aghvami, A. H.

    1988-12-01

    The application of 16-ary differentially encoded quadrature amplitude modulation (16-ary-DEQAM) signals to a regenerative satellite system is discussed. Four different bandwidths of the transmitted signal were tested together with different levels of output back-off in the high-power amplifier (HPA) at the transmitter. It is shown that the performance is improved when the predistortion of the 16-ary DEQAM signal is used to reduce the nonlinear distortion of the HPA.