Reduced Dietary Sodium Intake Increases Heart Rate

DEFF Research Database (Denmark)

Graudal, Niels A; Hubeck-Graudal, Thorbjørn; Jürgens, Gesche

2016-01-01

Reduced dietary sodium intake (sodium reduction) increases heart rate in some studies of animals and humans. As heart rate is independently associated with the development of heart failure and increased risk of premature death a potential increase in heart rate could be a harmful side......-effect of sodium reduction. The purpose of the present meta-analysis was to investigate the effect of sodium reduction on heart rate. Relevant studies were retrieved from an updated pool of 176 randomized controlled trials (RCTs) published in the period 1973-2014. Sixty-three of the RCTs including 72 study...... populations reported data on heart rate. In a meta-analysis of these data sodium reduction increased heart rate with 1.65 beats per minute [95% CI: 1.19, 2.11], p heart rate. This effect was independent of baseline blood pressure. In conclusion sodium reduction...

Communication satellite applications

Science.gov (United States)

Pelton, Joseph N.

The status and future of the technologies, numbers and services provided by communications satellites worldwide are explored. The evolution of Intelsat satellites and the associated earth terminals toward high-rate all-digital telephony, data, facsimile, videophone, videoconferencing and DBS capabilities are described. The capabilities, services and usage of the Intersputnik, Eutelsat, Arabsat and Palapa systems are also outlined. Domestic satellite communications by means of the Molniya, ANIK, Olympus, Intelsat and Palapa spacecraft are outlined, noting the fast growth of the market and the growing number of different satellite manufacturers. The technical, economic and service definition issues surrounding DBS systems are discussed, along with presently operating and planned maritime and aeronautical communications and positioning systems. Features of search and rescue and tracking, data, and relay satellite systems are summarized, and services offered or which will be offered by every existing or planned communication satellite worldwide are tabulated.

77 FR 6949 - Tracking and Data Relay Satellite System (TDRSS) Rates for Non-U.S. Government Customers

Science.gov (United States)

2012-02-10

... Tracking and Data Relay Satellite System (TDRSS) Rates for Non- U.S. Government Customers AGENCY: National... customer flexibility, allowing more efficient use of the system. This notion was never implemented in the... commercial customers, as well as Arctic and Antarctic science programs. In this direct final rule, NASA is...

75 FR 32228 - Rate Adjustment for the Satellite Carrier Compulsory License

Science.gov (United States)

2010-06-07

... voluntary negotiation period for the purpose of determining the royalty fees to be paid by satellite... President on May 27, 2010. Satellite carriers pay royalties based on a flat, per-subscriber, per-month fee... initiation of the voluntary negotiation proceedings for the purpose of determining the royalty fee to be paid...

Stress level in wild harbour porpoises (Phocoena phocoena) during satellite tagging measured by respiration, heart rate and cortisol

DEFF Research Database (Denmark)

Eskesen, Ida Grønborg; Teilmann, J.; Geertsen, B. M.

2009-01-01

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were...... between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based oil the factors investigated, on how to reduce stress during handling. However, pouring water over the animal...

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.

Stage-discharge rating curves based on satellite altimetry and modeled discharge in the Amazon basin

OpenAIRE

Paris, Adrien; Dias de Paiva, Rodrigo; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stephane; Garambois, Pierre-André; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frederique

2016-01-01

In this study, rating curves (RCs) were determined by applying satellite altimetry to a poorly gauged basin. This study demonstrates the synergistic application of remote sensing and watershed modeling to capture the dynamics and quantity of flow in the Amazon River Basin, respectively. Three major advancements for estimating basin-scale patterns in river discharge are described. The first advancement is the preservation of the hydrological meanings of the parameters expressed by ...

Coded throughput performance simulations for the time-varying satellite channel. M.S. Thesis

Science.gov (United States)

Han, LI

1995-01-01

The design of a reliable satellite communication link involving the data transfer from a small, low-orbit satellite to a ground station, but through a geostationary satellite, was examined. In such a scenario, the received signal power to noise density ratio increases as the transmitting low-orbit satellite comes into view, and then decreases as it then departs, resulting in a short-duration, time-varying communication link. The optimal values of the small satellite antenna beamwidth, signaling rate, modulation scheme and the theoretical link throughput (in bits per day) have been determined. The goal of this thesis is to choose a practical coding scheme which maximizes the daily link throughput while satisfying a prescribed probability of error requirement. We examine the throughput of both fixed rate and variable rate concatenated forward error correction (FEC) coding schemes for the additive white Gaussian noise (AWGN) channel, and then examine the effect of radio frequency interference (RFI) on the best coding scheme among them. Interleaving is used to mitigate degradation due to RFI. It was found that the variable rate concatenated coding scheme could achieve 74 percent of the theoretical throughput, equivalent to 1.11 Gbits/day based on the cutoff rate R(sub 0). For comparison, 87 percent is achievable for AWGN-only case.

Error resilient H.264/AVC Video over Satellite for low Packet Loss Rates

DEFF Research Database (Denmark)

Aghito, Shankar Manuel; Forchhammer, Søren; Andersen, Jakob Dahl

2007-01-01

The performance of video over satellite is simulated. The error resilience tools of intra macroblock refresh and slicing are optimized for live broadcast video over satellite. The improved performance using feedback, using a cross- layer approach, over the satellite link is also simulated. The ne...

Global determination of rating curves in the Amazon basin from satellite altimetry

Science.gov (United States)

Paris, Adrien; Paiva, Rodrigo C. D.; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stéphane; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frédérique

2014-05-01

The Amazonian basin is the largest hydrological basin all over the world. Over the past few years, it has experienced an unusual succession of extreme droughts and floods, which origin is still a matter of debate. One of the major issues in understanding such events is to get discharge series distributed over the entire basin. Satellite altimetry can be used to improve our knowledge of the hydrological stream flow conditions in the basin, through rating curves. Rating curves are mathematical relationships between stage and discharge at a given place. The common way to determine the parameters of the relationship is to compute the non-linear regression between the discharge and stage series. In this study, the discharge data was obtained by simulation through the entire basin using the MGB-IPH model with TRMM Merge input rainfall data and assimilation of gage data, run from 1998 to 2009. The stage dataset is made of ~900 altimetry series at ENVISAT and Jason-2 virtual stations, sampling the stages over more than a hundred of rivers in the basin. Altimetry series span between 2002 and 2011. In the present work we present the benefits of using stochastic methods instead of probabilistic ones to determine a dataset of rating curve parameters which are hydrologicaly meaningful throughout the entire Amazon basin. The rating curve parameters have been computed using an optimization technique based on Markov Chain Monte Carlo sampler and Bayesian inference scheme. This technique provides an estimate of the best value for the parameters together with their posterior probability distribution, allowing the determination of a credibility interval for calculated discharge. Also the error over discharges estimates from the MGB-IPH model is included in the rating curve determination. These MGB-IPH errors come from either errors in the discharge derived from the gage readings or errors in the satellite rainfall estimates. The present experiment shows that the stochastic approach

Effective fiber hypertrophy in satellite cell-depleted skeletal muscle

Science.gov (United States)

McCarthy, John J.; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B.; Srikuea, Ratchakrit; Lawson, Benjamin A.; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S.; Esser, Karyn A.; Dupont-Versteegden, Esther E.; Peterson, Charlotte A.

2011-01-01

An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca2+ sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells. PMID:21828094

Satellite Fault Diagnosis Using Support Vector Machines Based on a Hybrid Voting Mechanism

Science.gov (United States)

Yang, Shuqiang; Zhu, Xiaoqian; Jin, Songchang; Wang, Xiang

2014-01-01

The satellite fault diagnosis has an important role in enhancing the safety, reliability, and availability of the satellite system. However, the problem of enormous parameters and multiple faults makes a challenge to the satellite fault diagnosis. The interactions between parameters and misclassifications from multiple faults will increase the false alarm rate and the false negative rate. On the other hand, for each satellite fault, there is not enough fault data for training. To most of the classification algorithms, it will degrade the performance of model. In this paper, we proposed an improving SVM based on a hybrid voting mechanism (HVM-SVM) to deal with the problem of enormous parameters, multiple faults, and small samples. Many experimental results show that the accuracy of fault diagnosis using HVM-SVM is improved. PMID:25215324

Satellite Fault Diagnosis Using Support Vector Machines Based on a Hybrid Voting Mechanism

Directory of Open Access Journals (Sweden)

Hong Yin

2014-01-01

Full Text Available The satellite fault diagnosis has an important role in enhancing the safety, reliability, and availability of the satellite system. However, the problem of enormous parameters and multiple faults makes a challenge to the satellite fault diagnosis. The interactions between parameters and misclassifications from multiple faults will increase the false alarm rate and the false negative rate. On the other hand, for each satellite fault, there is not enough fault data for training. To most of the classification algorithms, it will degrade the performance of model. In this paper, we proposed an improving SVM based on a hybrid voting mechanism (HVM-SVM to deal with the problem of enormous parameters, multiple faults, and small samples. Many experimental results show that the accuracy of fault diagnosis using HVM-SVM is improved.

Prediction Method for Rain Rate and Rain Propagation Attenuation for K-Band Satellite Communications Links in Tropical Areas

Directory of Open Access Journals (Sweden)

Baso Maruddani

2015-01-01

Full Text Available This paper deals with the prediction method using hidden Markov model (HMM for rain rate and rain propagation attenuation for K-band satellite communication link at tropical area. As is well known, the K-band frequency is susceptible of being affected by atmospheric condition, especially in rainy condition. The wavelength of K-band frequency which approaches to the size of rain droplet causes the signal strength is easily attenuated and absorbed by the rain droplet. In order to keep the quality of system performance for K-band satellite communication link, therefore a special attention has to be paid for rain rate and rain propagation attenuation. Thus, a prediction method for rain rate and rain propagation attenuation based on HMM is developed to process the measurement data. The measured and predicted data are then compared with the ITU-R recommendation. From the result, it is shown that the measured and predicted data show similarity with the model of ITU-R P.837-5 recommendation for rain rate and the model of ITU-R P.618-10 recommendation for rain propagation attenuation. Meanwhile, statistical data for measured and predicted data such as fade duration and interfade duration have insignificant discrepancy with the model of ITU-R P.1623-1 recommendation.

Security Concepts for Satellite Links

Science.gov (United States)

Tobehn, C.; Penné, B.; Rathje, R.; Weigl, A.; Gorecki, Ch.; Michalik, H.

2008-08-01

The high costs to develop, launch and maintain a satellite network makes protecting the assets imperative. Attacks may be passive such as eavesdropping on the payload data. More serious threat are active attacks that try to gain control of the satellite, which may lead to the total lost of the satellite asset. To counter these threats, new satellite and ground systems are using cryptographic technologies to provide a range of services: confidentiality, entity & message authentication, and data integrity. Additionally, key management cryptographic services are required to support these services. This paper describes the key points of current satellite control and operations, that are authentication of the access to the satellite TMTC link and encryption of security relevant TM/TC data. For payload data management the key points are multi-user ground station access and high data rates both requiring frequent updates and uploads of keys with the corresponding key management methods. For secure satellite management authentication & key negotiation algorithms as HMAC-RIPEMD160, EC- DSA and EC-DH are used. Encryption of data uses algorithms as IDEA, AES, Triple-DES, or other. A channel coding and encryption unit for payload data provides download data rates up to Nx250 Mbps. The presented concepts are based on our experience and heritage of the security systems for all German MOD satellite projects (SATCOMBw2, SAR-Lupe multi- satellite system and German-French SAR-Lupe-Helios- II systems inter-operability) as well as for further international (KOMPSAT-II Payload data link system) and ESA activities (TMTC security and GMES).

Protein Availability and Satellite Cell Dynamics in Skeletal Muscle.

Science.gov (United States)

Shamim, Baubak; Hawley, John A; Camera, Donny M

2018-06-01

Human skeletal muscle satellite cells are activated in response to both resistance and endurance exercise. It was initially proposed that satellite cell proliferation and differentiation were only required to support resistance exercise-induced hypertrophy. However, satellite cells may also play a role in muscle fibre remodelling after endurance-based exercise and extracellular matrix regulation. Given the importance of dietary protein, particularly branched chain amino acids, in supporting myofibrillar and mitochondrial adaptations to both resistance and endurance-based training, a greater understanding of how protein intake impacts satellite cell activity would provide further insight into the mechanisms governing skeletal muscle remodelling with exercise. While many studies have investigated the capacity for protein ingestion to increase post-exercise rates of muscle protein synthesis, few investigations have examined the role for protein ingestion to modulate satellite cell activity. Here we review the molecular mechanisms controlling the activation of satellite cells in response to mechanical stress and protein intake in both in vitro and in vivo models. We provide a mechanistic framework that describes how protein ingestion may enhance satellite activity and promote exercise adaptations in human skeletal muscle.

76 FR 29963 - Rate Increase Disclosure and Review

Science.gov (United States)

2011-05-23

... for the product associated with the rate increase; and (8) employee and executive compensation data... 154 Rate Increase Disclosure and Review; Final Rule #0;#0;Federal Register / Vol. 76 , No. 99 / Monday... CFR Part 154 [CMS-9999-FC] RIN 0938-AQ68 Rate Increase Disclosure and Review AGENCY: Center for...

MASSIVE SATELLITES OF CLOSE-IN GAS GIANT EXOPLANETS

International Nuclear Information System (INIS)

Cassidy, Timothy A.; Johnson, Robert E.; Mendez, Rolando; Arras, Phil; Skrutskie, Michael F.

2009-01-01

We study the orbits, tidal heating and mass loss from satellites around close-in gas giant exoplanets. The focus is on large satellites which are potentially observable by their transit signature. We argue that even Earth-size satellites around hot Jupiters can be immune to destruction by orbital decay; detection of such a massive satellite would strongly constrain theories of tidal dissipation in gas giants, in a manner complementary to orbital circularization. The star's gravity induces significant periodic eccentricity in the satellite's orbit. The resulting tidal heating rates, per unit mass, are far in excess of Io's and dominate radioactive heating out to planet orbital periods of months for reasonable satellite tidal Q. Inside planet orbital periods of about a week, tidal heating can completely melt the satellite. Lastly, we compute an upper limit to the satellite mass loss rate due to thermal evaporation from the surface, valid if the satellite's atmosphere is thin and vapor pressure is negligible. Using this upper limit, we find that although rocky satellites around hot Jupiters with orbital periods less than a few days can be significantly evaporated in their lifetimes, detectable satellites suffer negligible mass loss at longer orbital periods.

New Generation of Broadcasting Satellite Systems: New Markets and Business Developments

Science.gov (United States)

Perrot, Bruno; Michel, Cyril; Villaret, Stéfanie

2002-01-01

Since the deployment of the first Digital Broadcasting Satellite Systems, European satellite operators and service providers have been faced with the continuously increasing demand for Digital Broadcasting Services. Their success is built on the availability of the MPEG and DVB standards. Undoubtedly, conventional digital television broadcasting is today the `Killer' application. Various service providers already offer multimedia applications through DVB-S systems based upon the `Push' technology. Although these services do not currently represent the core business for broadcasting satellite operators, their percentage is increasing. `Push' technology services include Data Carousel, Webcasting, Turbo Internet, File casting and so on. Such technology can support the implementation of different emerging multimedia services scenarios from Newsgroups, Network collaborative learning, and tele-medicine, to others that may be invented in the near future. The penetration rate of multi-channel television reception is still increasing. Broadcasting satellites benefit both from the development of new, more segmented and sophisticated offers and from the development of Internet services. Satellite is likely to enter these new markets at different levels of the value chain: Even if the satellite has demonstrated its capacity to fully serve the television, combinations with other networks may be necessary to address the new markets: at the consumer premises, Internet-related services will require a return path; at the backbone level, satellite becomes a component of a full telecommunications solution. This article focuses on the European market and proposes:

Soviet satellite communications science and technology

Energy Technology Data Exchange (ETDEWEB)

Birch, J.N.; Campanella, S.J.; Gordon, G.D.; McElroy, D.R.; Pritchard, W.L.; Stamminger, R.

1991-08-01

This is a report by six US scientists and engineers concerning the current state of the art and projections of future Soviet satellite communications technologies. The panel members are experts in satellite stabilization, spacecraft environments, space power generation, launch systems, spacecraft communications sciences and technologies, onboard processing, ground stations, and other technologies that impact communications. The panel assessed the Soviet ability to support high-data-rate space missions at 128 Mbps by evaluating current and projected Soviet satellite communications technologies. A variety of space missions were considered, including Earth-to-Earth communications via satellites in geostationary or highly elliptical orbits, those missions that require space-to-Earth communications via a direct path and those missions that require space-to-Earth communications via a relay satellite. Soviet satellite communications capability, in most cases, is 10 years behind that of the United States and other industrialized nations. However, based upon an analysis of communications links needed to support these missions using current Soviet capabilities, it is well within the current Soviet technology to support certain space missions outlined above at rates of 128 Mbps or higher, although published literature clearly shows that the Soviet Union has not exceeded 60 Mbps in its current space system. These analyses are necessary but not sufficient to determine mission data rates, and other technologies such as onboard processing and storage could limit the mission data rate well below that which could actually be supported via the communications links. Presently, the Soviet Union appears to be content with data rates in the low-Earth-orbit relay via geostationary mode of 12 Mbps. This limit is a direct result of power amplifier limits, spacecraft antenna size, and the utilization of K{sub u}-band frequencies. 91 refs., 16 figs., 15 tabs.

Gaussian entanglement distribution via satellite

Science.gov (United States)

Hosseinidehaj, Nedasadat; Malaney, Robert

2015-02-01

In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

Analysis of Patient Visits and Collections After Opening a Satellite Pediatric Emergency Department.

Science.gov (United States)

Nichols, Katherine M; Caperell, Kerry; Cross, Keith; Duncan, Scott; Foster, Ben; Liu, Gil; Pritchard, Hank; Southard, Gary; Shinabery, Ben; Sutton, Brad; Kim, In K

2018-04-01

Satellite pediatric emergency departments (PEDs) have emerged as a strategy to increase patient capacity. We sought to determine the impact on patient visits, physician fee collections, and value of emergency department (ED) time at the primary PED after opening a nearby satellite PED. We also illustrate the spatial distribution of patient demographics and overlapping catchment areas for the primary and satellite PEDs using geographical information system. A structured, financial retrospective review was conducted. Aggregate patient demographic data and billing data were collected regarding physician fee charges, collections, and patient visits for both PEDs. All ED visits from January 2009 to December 2013 were analyzed. Geographical information system mapping using ArcGIS mapped ED patient visits. Patient visits at the primary PED were 53,050 in 2009 before the satellite PED opened. The primary PED visits increased after opening the satellite PED to 55,932 in 2013. The satellite PED visits increased to 21,590 in 2013. Collections per visit at the primary PED decreased from $105.13 per visit in 2011 to $86.91 per visit in 2013. Total collections at the satellite PED decreased per visit from $155.41 per visit in 2011 to $128.53 per visit in 2013. After opening a nearby satellite PED, patient visits at the primary PED did not substantially decrease, suggesting that there was a previously unrecognized demand for PED services. The collections per ED visit were greater at the satellite ED, likely due to a higher collection rate.

Effects of systematic sampling on satellite estimates of deforestation rates

International Nuclear Information System (INIS)

Steininger, M K; Godoy, F; Harper, G

2009-01-01

Options for satellite monitoring of deforestation rates over large areas include the use of sampling. Sampling may reduce the cost of monitoring but is also a source of error in estimates of areas and rates. A common sampling approach is systematic sampling, in which sample units of a constant size are distributed in some regular manner, such as a grid. The proposed approach for the 2010 Forest Resources Assessment (FRA) of the UN Food and Agriculture Organization (FAO) is a systematic sample of 10 km wide squares at every 1 deg. intersection of latitude and longitude. We assessed the outcome of this and other systematic samples for estimating deforestation at national, sub-national and continental levels. The study is based on digital data on deforestation patterns for the five Amazonian countries outside Brazil plus the Brazilian Amazon. We tested these schemes by varying sample-unit size and frequency. We calculated two estimates of sampling error. First we calculated the standard errors, based on the size, variance and covariance of the samples, and from this calculated the 95% confidence intervals (CI). Second, we calculated the actual errors, based on the difference between the sample-based estimates and the estimates from the full-coverage maps. At the continental level, the 1 deg., 10 km scheme had a CI of 21% and an actual error of 8%. At the national level, this scheme had CIs of 126% for Ecuador and up to 67% for other countries. At this level, increasing sampling density to every 0.25 deg. produced a CI of 32% for Ecuador and CIs of up to 25% for other countries, with only Brazil having a CI of less than 10%. Actual errors were within the limits of the CIs in all but two of the 56 cases. Actual errors were half or less of the CIs in all but eight of these cases. These results indicate that the FRA 2010 should have CIs of smaller than or close to 10% at the continental level. However, systematic sampling at the national level yields large CIs unless the

Increasing Running Step Rate Reduces Patellofemoral Joint Forces

Science.gov (United States)

Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

2013-01-01

Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

Real-Time Rain Rate Evaluation via Satellite Downlink Signal Attenuation Measurement.

Science.gov (United States)

Giannetti, Filippo; Reggiannini, Ruggero; Moretti, Marco; Adirosi, Elisa; Baldini, Luca; Facheris, Luca; Antonini, Andrea; Melani, Samantha; Bacci, Giacomo; Petrolino, Antonio; Vaccaro, Attilio

2017-08-12

We present the NEFOCAST project (named by the contraction of "Nefele", which is the Italian spelling for the mythological cloud nymph Nephele, and "forecast"), funded by the Tuscany Region, about the feasibility of a system for the detection and monitoring of precipitation fields over the regional territory based on the use of a widespread network of new-generation Eutelsat "SmartLNB" (smart low-noise block converter) domestic terminals. Though primarily intended for interactive satellite services, these devices can also be used as weather sensors, as they have the capability of measuring the rain-induced attenuation incurred by the downlink signal and relaying it on an auxiliary return channel. We illustrate the NEFOCAST system architecture, consisting of the network of ground sensor terminals, the space segment, and the service center, which has the task of processing the information relayed by the terminals for generating rain field maps. We discuss a few methods that allow the conversion of a rain attenuation measurement into an instantaneous rainfall rate. Specifically, we discuss an exponential model relating the specific rain attenuation to the rainfall rate, whose coefficients were obtained from extensive experimental data. The above model permits the inferring of the rainfall rate from the total signal attenuation provided by the SmartLNB and from the link geometry knowledge. Some preliminary results obtained from a SmartLNB installed in Pisa are presented and compared with the output of a conventional tipping bucket rain gauge. It is shown that the NEFOCAST sensor is able to track the fast-varying rainfall rate accurately with no delay, as opposed to a conventional gauge.

Survey and analysis of satellite-based telemedicine projects involving Japan and developing nations: investigation of transmission rates, channel numbers, and node numbers.

Science.gov (United States)

Nakajima, I; Natori, M; Takizawa, M; Kaihara, S

2001-01-01

We surveyed interactive telemedicine projects via telecommunications satellite (AMINE-PARTNERS, Post-PARTNERS, and Shinshu University Project using Inmarsat satellites) offered by Japan as assistance to developing countries. The survey helped clarify channel occupation time and data transfer rates. Using our survey results, we proposed an optimized satellite model with VSATs simulating the number of required channels and bandwidth magnitude. For future implementation of VSATs for medical use in developing nations, design of telecommunication channels should take into consideration TCP/IP-based operations. We calculated that one hub station with 30-76 VSATs in developing nation can be operated on bandwidth 6 Mbps using with 128 Kbps videoconferencing system for teleconsultation and teleconference, and linking with Internet.

Mixed lactate and caffeine compound increases satellite cell activity and anabolic signals for muscle hypertrophy.

Science.gov (United States)

Oishi, Yoshimi; Tsukamoto, Hayato; Yokokawa, Takumi; Hirotsu, Keisuke; Shimazu, Mariko; Uchida, Kenji; Tomi, Hironori; Higashida, Kazuhiko; Iwanaka, Nobumasa; Hashimoto, Takeshi

2015-03-15

We examined whether a mixed lactate and caffeine compound (LC) could effectively elicit proliferation and differentiation of satellite cells or activate anabolic signals in skeletal muscles. We cultured C2C12 cells with either lactate or LC for 6 h. We found that lactate significantly increased myogenin and follistatin protein levels and phosphorylation of P70S6K while decreasing the levels of myostatin relative to the control. LC significantly increased protein levels of Pax7, MyoD, and Ki67 in addition to myogenin, relative to control. LC also significantly increased follistatin expression relative to control and stimulated phosphorylation of mTOR and P70S6K. In an in vivo study, male F344/DuCrlCrlj rats were assigned to control (Sed, n = 10), exercise (Ex, n = 12), and LC supplementation (LCEx, n = 13) groups. LC was orally administered daily. The LCEx and Ex groups were exercised on a treadmill, running for 30 min at low intensity every other day for 4 wk. The LCEx group experienced a significant increase in the mass of the gastrocnemius (GA) and tibialis anterior (TA) relative to both the Sed and Ex groups. Furthermore, the LCEx group showed a significant increase in the total DNA content of TA compared with the Sed group. The LCEx group experienced a significant increase in myogenin and follistatin expression of GA relative to the Ex group. These results suggest that administration of LC can effectively increase muscle mass concomitant with elevated numbers of myonuclei, even with low-intensity exercise training, via activated satellite cells and anabolic signals. Copyright © 2015 the American Physiological Society.

Are rates of pediatric bipolar disorder increasing?

DEFF Research Database (Denmark)

Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

2014-01-01

Studies from the USA suggest that rates of pediatric bipolar disorder have increased since the mid-90s, but no study outside the USA has been published on the rates of pediatric bipolar disorder. Further, it is unclear whether an increase in rates reflects a true increase in the illness or more...... diagnostic attention. Using nationwide registers of all inpatients and outpatients contacts to all psychiatric hospitals in Denmark, we investigated (1) gender-specific rates of incident pediatric mania/bipolar disorder during a period from 1995 to 2012, (2) whether age and other characteristics...... for pediatric mania/bipolar disorder changed during the calendar period (1995 to 2003 versus 2004 to 2012), and (3) whether the diagnosis is more often made at first psychiatric contact in recent time compared to earlier according to gender. Totally, 346 patients got a main diagnosis of a manic episode (F30...

Spectrum and power allocation in cognitive multi-beam satellite communications with flexible satellite payloads

Science.gov (United States)

Liu, Zhihui; Wang, Haitao; Dong, Tao; Yin, Jie; Zhang, Tingting; Guo, Hui; Li, Dequan

2018-02-01

In this paper, the cognitive multi-beam satellite system, i.e., two satellite networks coexist through underlay spectrum sharing, is studied, and the power and spectrum allocation method is employed for interference control and throughput maximization. Specifically, the multi-beam satellite with flexible payload reuses the authorized spectrum of the primary satellite, adjusting its transmission band as well as power for each beam to limit its interference on the primary satellite below the prescribed threshold and maximize its own achievable rate. This power and spectrum allocation problem is formulated as a mixed nonconvex programming. For effective solving, we first introduce the concept of signal to leakage plus noise ratio (SLNR) to decouple multiple transmit power variables in the both objective and constraint, and then propose a heuristic algorithm to assign spectrum sub-bands. After that, a stepwise plus slice-wise algorithm is proposed to implement the discrete power allocation. Finally, simulation results show that adopting cognitive technology can improve spectrum efficiency of the satellite communication.

Using high-resolution satellite radar to measure lava flow morphology, rheology, effusion rate and subsidence at El Reventador Volcano, Ecuador.

Science.gov (United States)

Biggs, J.; Arnold, D. W. D.; Mothes, P. A.; Anderson, K. R.; Albino, F.; Wadge, G.; Vallejo Vargas, S.; Ebmeier, S. K.

2017-12-01

There are relatively few studies of active lava flows of an andesitic rather than basaltic composition. The flow field at El Reventador volcano, Ecuador is a good example, but observations are hampered by persistent cloud cover. We use high resolution satellite radar from Radarsat-2 and TanDEM-X to map the dimensions of 43 lava flows extruded between 9 Feb 2012 and 24 Aug 2016. Flow height is measured using the width of radar shadow cast by steep sided features, or the difference in radar phase between two sensors separated in space. The cumulative volume of erupted material was 44.8M m3 dense rock equivalent with an average rate of 0.31 ± 0.02 m3s-1, similar to the long term average. The flows were mostly emplaced over durations shorter than the satellite repeat interval of 24 days and ranged in length from 0.3 to 1.7 km. We use the dimensions of the levees to estimate the flow yield strengths and compare measurements of diversions around barriers with observations from laboratory experiments. The rate of effusion, flow length and flow volume all decrease with time, and simple physics-based models can be equally well fit by a closed reservoir depressurising during the eruption with no magma recharge, or an open reservoir with a time-constant magma recharge rate of up to 0.35 ± 0.01 m3s-1. We propose that the conduit acts as magma capacitor and individual flows are volume-limited. Emplaced flows are subsiding at rates proportional to lava thickness that decay with time following a square-root relationship. Radar observations, such as those presented here, could be used to map and measure properties of evolving lava flow fields at other remote or difficult to monitor volcanoes. Physics-based models can be run into the future, but a sudden increase in flow length in 2017 seen by Sentinel illustrates that changes in magma supply can cause rapid changes in behavior, which remain challenging to forecast.

Analysis of Visual Interpretation of Satellite Data

Science.gov (United States)

Svatonova, H.

2016-06-01

Millions of people of all ages and expertise are using satellite and aerial data as an important input for their work in many different fields. Satellite data are also gradually finding a new place in education, especially in the fields of geography and in environmental issues. The article presents the results of an extensive research in the area of visual interpretation of image data carried out in the years 2013 - 2015 in the Czech Republic. The research was aimed at comparing the success rate of the interpretation of satellite data in relation to a) the substrates (to the selected colourfulness, the type of depicted landscape or special elements in the landscape) and b) to selected characteristics of users (expertise, gender, age). The results of the research showed that (1) false colour images have a slightly higher percentage of successful interpretation than natural colour images, (2) colourfulness of an element expected or rehearsed by the user (regardless of the real natural colour) increases the success rate of identifying the element (3) experts are faster in interpreting visual data than non-experts, with the same degree of accuracy of solving the task, and (4) men and women are equally successful in the interpretation of visual image data.

ANALYSIS OF VISUAL INTERPRETATION OF SATELLITE DATA

Directory of Open Access Journals (Sweden)

H. Svatonova

2016-06-01

Full Text Available Millions of people of all ages and expertise are using satellite and aerial data as an important input for their work in many different fields. Satellite data are also gradually finding a new place in education, especially in the fields of geography and in environmental issues. The article presents the results of an extensive research in the area of visual interpretation of image data carried out in the years 2013 - 2015 in the Czech Republic. The research was aimed at comparing the success rate of the interpretation of satellite data in relation to a the substrates (to the selected colourfulness, the type of depicted landscape or special elements in the landscape and b to selected characteristics of users (expertise, gender, age. The results of the research showed that (1 false colour images have a slightly higher percentage of successful interpretation than natural colour images, (2 colourfulness of an element expected or rehearsed by the user (regardless of the real natural colour increases the success rate of identifying the element (3 experts are faster in interpreting visual data than non-experts, with the same degree of accuracy of solving the task, and (4 men and women are equally successful in the interpretation of visual image data.

Land-mobile satellite excess path loss measurements

Science.gov (United States)

Hess, G. C.

1980-05-01

An experiment conducted with the ATS-6 satellite to determine the additional path loss over free-space loss experienced by land-mobile communication links is described. This excess path loss is measured as a function of 1) local environment, 2) vehicle heading, 3) link frequency, 4) satellite elevation angle, and 5) street side. A statistical description of excess loss developed from the data shows that the first two parameters dominate. Excess path loss on the order of 25 dB is typical in urban situations, but decreases to under 10 dB in suburban/rural areas. Spaced antenna selection diversity is found to provide only a slight decrease (4 dB, typically) in the urban excess path loss observed. Level crossing rates are depressed in satellite links relative to those of Rayleigh-faded terrestrial links, but increases in average fade durations tend to offset that advantage. The measurements show that the excess path loss difference between 860-MHz links and 1550-MHz links is generally negligible.

Servicing communication satellites in geostationary orbit

Science.gov (United States)

Russell, Paul K.; Price, Kent M.

1990-01-01

The econmic benefits of a LEO space station are quantified by identifying alternative operating scenarios utilizing the space station's transportation facilities and assembly and repair facilities. Particular consideration is given to the analysis of the impact of on-orbit assembly and servicing on a typical communications satellite is analyzed. The results of this study show that on-orbit servicing can increase the internal rate of return by as much as 30 percent.

DS-CDMA satellite diversity reception for personal satellite communication: Downlink performance analysis

Science.gov (United States)

DeGaudenzi, Riccardo; Giannetti, Filippo

1995-01-01

The downlink of a satellite-mobile personal communication system employing power-controlled Direct Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

Mechanics of arterial subfailure with increasing loading rate.

Science.gov (United States)

Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A

2007-01-01

Arterial subfailure leads to delayed symptomatology and high morbidity and mortality rates, particularly for the thoracic aorta and carotid arteries. Although arterial injuries occur during high-velocity automotive collisions, previous studies of arterial subfailure focused on quasi-static loading. This investigation subjected aortic segments to increasing loading rates to quantify effects on elastic, subfailure, and ultimate vessel mechanics. Sixty-two specimens were axially distracted, and 92% demonstrated subfailure before ultimate failure. With increasing loading rate, stress at initial subfailure and ultimate failure significantly increased, and strain at initial subfailure and ultimate failure significantly decreased. Present results indicate increased susceptibility for arterial subfailure and/or dissection under higher-rate extension. According to the present results, automotive occupants are at greater risk of arterial injury under higher velocity impacts due to greater body segment motions in addition to decreased strain tolerance to subfailure and catastrophic failure.

Satellite telemetry reveals higher fishing mortality rates than previously estimated, suggesting overfishing of an apex marine predator.

Science.gov (United States)

Byrne, Michael E; Cortés, Enric; Vaudo, Jeremy J; Harvey, Guy C McN; Sampson, Mark; Wetherbee, Bradley M; Shivji, Mahmood

2017-08-16

Overfishing is a primary cause of population declines for many shark species of conservation concern. However, means of obtaining information on fishery interactions and mortality, necessary for the development of successful conservation strategies, are often fisheries-dependent and of questionable quality for many species of commercially exploited pelagic sharks. We used satellite telemetry as a fisheries-independent tool to document fisheries interactions, and quantify fishing mortality of the highly migratory shortfin mako shark ( Isurus oxyrinchus ) in the western North Atlantic Ocean. Forty satellite-tagged shortfin mako sharks tracked over 3 years entered the Exclusive Economic Zones of 19 countries and were harvested in fisheries of five countries, with 30% of tagged sharks harvested. Our tagging-derived estimates of instantaneous fishing mortality rates ( F = 0.19-0.56) were 10-fold higher than previous estimates from fisheries-dependent data (approx. 0.015-0.024), suggesting data used in stock assessments may considerably underestimate fishing mortality. Additionally, our estimates of F were greater than those associated with maximum sustainable yield, suggesting a state of overfishing. This information has direct application to evaluations of stock status and for effective management of populations, and thus satellite tagging studies have potential to provide more accurate estimates of fishing mortality and survival than traditional fisheries-dependent methodology. © 2017 The Author(s).

Satellites

International Nuclear Information System (INIS)

Burns, J.A.; Matthews, M.S.

1986-01-01

The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system

Satellite switched FDMA advanced communication technology satellite program

Science.gov (United States)

Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

1982-01-01

The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

Increasing preferred step rate during running reduces plantar pressures.

Science.gov (United States)

Gerrard, James M; Bonanno, Daniel R

2018-01-01

Increasing preferred step rate during running is a commonly used strategy in the management of running-related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty-two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar-X in-shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kPa; P=.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P=.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P=.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kPa; P=.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P=.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications

Directory of Open Access Journals (Sweden)

Luca Giugno

2007-05-01

Full Text Available This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramér-Rao bounds (CRBs for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.

GALAXY EVOLUTION AT HIGH REDSHIFT: OBSCURED STAR FORMATION, GRB RATES, COSMIC REIONIZATION, AND MISSING SATELLITES

Energy Technology Data Exchange (ETDEWEB)

Lapi, A.; Mancuso, C.; Celotti, A.; Danese, L. [SISSA, Via Bonomea 265, I-34136 Trieste (Italy)

2017-01-20

We provide a holistic view of galaxy evolution at high redshifts z ≳ 4, which incorporates the constraints from various astrophysical/cosmological probes, including the estimate of the cosmic star formation rate (SFR) density from UV/IR surveys and long gamma-ray burst (GRBs) rates, the cosmic reionization history following the latest Planck measurements, and the missing satellites issue. We achieve this goal in a model-independent way by exploiting the SFR functions derived by Mancuso et al. on the basis of an educated extrapolation of the latest UV/far-IR data from HST / Herschel , and already tested against a number of independent observables. Our SFR functions integrated down to a UV magnitude limit M {sub UV} ≲ −13 (or SFR limit around 10{sup −2} M {sub ⊙} yr{sup −1}) produce a cosmic SFR density in excellent agreement with recent determinations from IR surveys and, taking into account a metallicity ceiling Z ≲ Z {sub ⊙}/2, with the estimates from long GRB rates. They also yield a cosmic reionization history consistent with that implied by the recent measurements of the Planck mission of the electron scattering optical depth τ {sub es} ≈ 0.058; remarkably, this result is obtained under a conceivable assumption regarding the average value f {sub esc} ≈ 0.1 of the escape fraction for ionizing photons. We demonstrate via the abundance-matching technique that the above constraints concurrently imply galaxy formation becoming inefficient within dark matter halos of mass below a few 10{sup 8} M {sub ⊙}; pleasingly, such a limit is also required so as not to run into the missing satellites issue. Finally, we predict a downturn of the Galaxy luminosity function faintward of M {sub UV} ≲ −12, and stress that its detailed shape, to be plausibly probed in the near future by the JWST , will be extremely informative on the astrophysics of galaxy formation in small halos, or even on the microscopic nature of the dark matter.

Monitoring volcanic thermal activity by Robust Satellite Techniques: achievements and perspectives

Science.gov (United States)

Tramutoli, V.; Marchese, F.; Mazzeo, G.; Pergola, N.

2009-12-01

Satellite data have been increasingly used in last decades to study active volcanoes and to monitor thermal activity variation in space-time domain. Several satellite techniques and original methods have been developed and tested, devoted to hotspot detection and thermal monitoring. Among them, a multi-temporal approach, named RST (Robust Satellite Techniques), has shown high performances in detecting hotspots, with a low false positive rate under different observational and atmospheric conditions, providing also a potential toward low-level thermal anomalies which may announce incoming eruptions. As the RST scheme is intrinsically exportable on different geographic areas and satellite sensors, it has been applied and tested on a number of volcanoes and in different environmental conditions. This work presents major results and outcomes of studies carried out on Etna and Stromboli (Italy), Merapi (Java Indonesia), Asamayama (Japan), Jebel Al Tair (Yemen) by using different satellite systems and sensors (e.g. NOAA-AVHRR, EOS-MODIS, MSG-SEVIRI). Performances on hotspot detection, early warning and real-time monitoring, together with capabilities in possible thermal precursor identification, will be presented and discussed.

R&D of a Next Generation LEO System for Global Multimedia Mobile Satellite Communications

Science.gov (United States)

Morikawa, E.; Motoyoshi, S.; Koyama, Y.; Suzuki, R.; Yasuda, Y.

2002-01-01

Next-generation LEO System Research Center (NeLS) was formed in the end of 1997 as a research group under the Telecommunications Advancement Organization of Japan, in cooperation with the telecommunications operators, manufacturers, universities and governmental research organization. The aim of this project is to develop new technology for global multimedia mobile satellite communications services with a user data rate around 2Mbps for handy terminals. component of the IMT-2000, and the second generation of the big-LEO systems. In prosecuting this project, two-phase approach, phase 1 and phase 2, is considered. Phase 1 is the system definition and development of key technologies. In Phase 2, we plan to verify the developed technology in Phase 1 on space. From this year we shifted the stage to Phase 2, and are now developing the prototype of on-board communication systems for flight tests, which will be planed at around 2006. The satellite altitude is assumed to be 1200 km in order to reduce the number of satellites, to avoid the Van Allen radiation belts and to increase the minimum elevation angle. Ten of the circular orbits with 55 degree of inclination are selected to cover the earth surface from -70 to 70 degree in latitude. 12 satellites are positioned at regular intervals in each orbit. In this case, the minimum elevation angle from the user terminal can be keep more than 20 degree for the visibility of the satellite, and 15 degree for simultaneous visibility of two satellites. Then, NeLS Research Center was focusing on the development of key technologies as the phase 1 project. Four kinds of key technologies; DBF satellite antenna, optical inter-satellite link system, satellite network technology with on-board ATM switch and variable rate modulation were selected. Satellite Antenna Technology: Development of on-board direct radiating active phased array antenna with digital beam forming technology would be one of the most important breakthroughs for the

The C3PO project: a laser communication system concept for small satellites

Science.gov (United States)

d'Humières, Benoît; Esmiller, Bruno; Gouy, Yann; Steck, Emilie; Quintana, Crisanto; Faulkner, Graham; O'Brien, Dominic; Sproll, Fabian; Wagner, Paul; Hampf, Daniel; Riede, Wolfgang; Salter, Michael; Wang, Qin; Platt, Duncan; Jakonis, Darius; Piao, Xiaoyu; Karlsson, Mikael; Oberg, Olof; Petermann, Ingemar; Michalkiewicz, Aneta; Krezel, Jerzy; Debowska, Anna; Thueux, Yoann

2017-02-01

The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO1 system, "advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects", and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.

76 FR 74703 - Cost of Living Adjustment to Satellite Carrier Compulsory License Royalty Rates

Science.gov (United States)

2011-12-01

... Federal Regulations is amended as follows: PART 386--ADJUSTMENT OF ROYALTY FEES FOR SECONDARY... (b)(2)(iii) to read as follows: Sec. 386.2 Royalty fee for secondary transmission by satellite... LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 386 [Docket No. 2011-10 CRB Satellite COLA...

On-board processing for telecommunications satellites

Science.gov (United States)

Nuspl, P. P.; Dong, G.

1991-01-01

In this decade, communications satellite systems will probably face dramatic challenges from alternative transmission means. To balance and overcome such competition, and to prepare for new requirements, INTELSAT has developed several on-board processing techniques, including Satellite-Switched TDMA (SS-TDMA), Satellite-Switched FDMA (SS-FDMA), several Modulators/Demodulators (Modem), a Multicarrier Multiplexer and Demodulator MCDD), an International Business Service (IBS)/Intermediate Data Rate (IDR) BaseBand Processor (BBP), etc. Some proof-of-concept hardware and software were developed, and tested recently in the INTELSAT Technical Laboratories. These techniques and some test results are discussed.

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.

75 FR 75624 - Cost of Living Adjustment to Satellite Carrier Compulsory License Royalty Rates

Science.gov (United States)

2010-12-06

... ROYALTY FEES FOR SECONDARY TRANSMISSIONS BY SATELLITE CARRIERS 0 1. The authority citation for part 386... revising paragraphs (b)(1)(ii) and (b)(2)(ii) as follows: Sec. 386.2 Royalty fee for secondary transmission... LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 386 [Docket No. 2010-10 CRB Satellite COLA...

77 FR 70373 - Cost of Living Adjustment to Satellite Carrier Compulsory License Royalty Rates

Science.gov (United States)

2012-11-26

... ROYALTY FEES FOR SECONDARY TRANSMISSIONS BY SATELLITE CARRIERS 0 1. The authority citation for part 386... revising paragraphs (b)(1)(iv) and (b)(2)(iv) as follows: Sec. 386.2 Royalty fee for secondary transmission... LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 386 [Docket No. 2012-8 CRB Satellite COLA...

History of Satellite TV Broadcasting and Satellite Broadcasting Market in Turkey

Directory of Open Access Journals (Sweden)

Mihalis KUYUCU

2015-09-01

Full Text Available The present study analyses the satellite broadcasting that is the first important development that emerged as a result of digitalization in communication technologies and its reflections in Turkey. As the first milestone in the globalization of television broadcasting, satellite broadcasting provided substantial contribution towards the development of the media. Satellite bro adcasting both increased the broadcasting quality and geographical coverage of the television media. A conceptual study was carried out in the first part of the study in connection with the history of satellite broadcasting in Turkey and across the world. In the research part of the study, an analysis was performed on 160 television channels that broadcast in Turkey via Turksat Satellite. Economic structure of the television channels broadcasting in Turkey via satellite was studied and an analysis was perfo rmed on the operational structure of the channels. As a result of the study, it was emphasized that the television channels broadcasting via satellite platform also use other platforms for the purpose of spreading their broadcasts and television channel ow ners make investments in different branches of the media, too. Capital owners invest in different business areas other than the media although television channels broadcasting via Turksat mostly focus on thematic broadcasting and make effort to generate ec onomic income from advertisements. Delays are encountered in the course of the convergence between the new media and television channels that broadcast only from the satellite platform and such television channels experience more economic problems than the other channels. New media and many TV broadcasting platforms emerged as a result of the developments in the communication technologies. In television broadcasting, satellite platform is not an effective platform on its own. Channels make effort to reach t o more people by using other platforms in addition to

Spread spectrum mobile communication experiment using ETS-V satellite

Science.gov (United States)

Ikegami, Tetsushi; Suzuki, Ryutaro; Kadowaki, Naoto; Taira, Shinichi; Sato, Nobuyasu

1990-01-01

The spread spectrum technique is attractive for application to mobile satellite communications, because of its random access capability, immunity to inter-system interference, and robustness to overloading. A novel direct sequence spread spectrum communication equipment is developed for land mobile satellite applications. The equipment is developed based on a matched filter technique to improve the initial acquisition performance. The data rate is 2.4 kilobits per sec. and the PN clock rate is 2.4552 mega-Hz. This equipment also has a function of measuring the multipath delay profile of land mobile satellite channel, making use of a correlation property of a PN code. This paper gives an outline of the equipment and the field test results with ETS-V satellite.

78 FR 71501 - Cost of Living Adjustment to Satellite Carrier Compulsory License Royalty Rates

Science.gov (United States)

2013-11-29

... follows: PART 386--ADJUSTMENT OF ROYALTY FEES FOR SECONDARY TRANSMISSIONS BY SATELLITE CARRIERS 0 1. The.... Section 386.2 is amended by revising paragraphs (b)(1)(v) and (b)(2)(v) as follows: Sec. 386.2 Royalty fee... LIBRARY OF CONGRESS Copyright Royalty Board 37 CFR Part 386 [Docket No. 2013-8 CRB Satellite COLA...

The mitochondrial uniporter controls fight or flight heart rate increases.

Science.gov (United States)

Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

2015-01-20

Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

Merapi 2010 eruption—Chronology and extrusion rates monitored with satellite radar and used in eruption forecasting

Science.gov (United States)

Pallister, John S.; Schneider, David; Griswold, Julia P.; Keeler, Ronald H.; Burton, William C.; Noyles, Christopher; Newhall, Christopher G.; Ratdomopurbo, Antonius

2013-01-01

Despite dense cloud cover, satellite-borne commercial Synthetic Aperture Radar (SAR) enabled frequent monitoring of Merapi volcano's 2010 eruption. Near-real-time interpretation of images derived from the amplitude of the SAR signals and timely delivery of these interpretations to those responsible for warnings, allowed satellite remote sensing for the first time to play an equal role with in situ seismic, geodetic and gas monitoring in guiding life-saving decisions during a major volcanic crisis. Our remotely sensed data provide an observational chronology for the main phase of the 2010 eruption, which lasted 12 days (26 October–7 November, 2010). Unlike the prolonged low-rate and relatively low explosivity dome-forming and collapse eruptions of recent decades at Merapi, the eruption began with an explosive eruption that produced a new summit crater on 26 October and was accompanied by an ash column and pyroclastic flows that extended 8 km down the flanks. This initial explosive event was followed by smaller explosive eruptions on 29 October–1 November, then by a period of rapid dome growth on 1–4 November, which produced a summit lava dome with a volume of ~ 5 × 106 m3. A paroxysmal VEI 4 magmatic eruption (with ash column to 17 km altitude) destroyed this dome, greatly enlarged the new summit crater and produced extensive pyroclastic flows (to ~ 16 km radial distance in the Gendol drainage) and surges during the night of 4–5 November. The paroxysmal eruption was followed by a period of jetting of gas and tephra and by a second short period (12 h) of rapid dome growth on 6 November. The eruption ended with low-level ash and steam emissions that buried the 6 November dome with tephra and continued at low levels until seismicity decreased to background levels by about 23 November. Our near-real-time commercial SAR documented the explosive events on 26 October and 4–5 November and high rates of dome growth (> 25 m3 s− 1). An event tree

Encryption protection for communication satellites

Science.gov (United States)

Sood, D. R.; Hoernig, O. W., Jr.

In connection with the growing importance of the commercial communication satellite systems and the introduction of new technological developments, users and operators of these systems become increasingly concerned with aspects of security. The user community is concerned with maintaining confidentiality and integrity of the information being transmitted over the satellite links, while the satellite operators are concerned about the safety of their assets in space. In response to these concerns, the commercial satellite operators are now taking steps to protect the communication information and the satellites. Thus, communication information is being protected by end-to-end encryption of the customer communication traffic. Attention is given to the selection of the NBS DES algorithm, the command protection systems, and the communication protection systems.

Using satellite-based measurements to explore ...

Science.gov (United States)

New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently spatially averaged) measurements of atmospheric conditions to diagnose the occurrence of NPF and NPF characteristics. We demonstrate the potential for using satellite-measurements of insolation (UV), trace gas concentrations (sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), formaldehyde (HCHO), ozone (O3)), aerosol optical properties (aerosol optical depth (AOD), Ångström exponent (AE)), and a proxy of biogenic volatile organic compound emissions (leaf area index (LAI), temperature (T)) as predictors for NPF characteristics: formation rates, growth rates, survival probabilities, and ultrafine particle (UFP) concentrations at five locations across North America. NPF at all sites is most frequent in spring, exhibits a one-day autocorrelation, and is associated with low condensational sink (AOD×AE) and HCHO concentrations, and high UV. However, there are important site-to-site variations in NPF frequency and characteristics, and in which of the predictor variables (particularly gas concentrations) significantly contribute to the explanatory power of regression models built to predict those characteristics. This finding may provide a partial explanation for the reported spatia

JPSS Preparations at the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis

Science.gov (United States)

Folmer, M. J.; Berndt, E.; Clark, J.; Orrison, A.; Kibler, J.; Sienkiewicz, J. M.; Nelson, J. A., Jr.; Goldberg, M.

2016-12-01

The National Oceanic and Atmospheric Administration (NOAA) Satellite Proving Ground (PG) for Marine, Precipitation, and Satellite Analysis (MPS) has been demonstrating and evaluating Suomi National Polar-orbiting Partnership (S-NPP) products along with other polar-orbiting satellite platforms in preparation for the Joint Polar Satellite System - 1 (JPSS-1) launch in March 2017. The first S-NPP imagery was made available to the MPS PG during the evolution of Hurricane Sandy in October 2012 and has since been popular in operations. Since this event the MPS PG Satellite Liaison has been working with forecasters on ways to integrate single-channel and multispectral imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Advanced Very High Resolution Radiometer (AVHRR)into operations to complement numerical weather prediction and geostationary satellite savvy National Weather Service (NWS) National Centers. Additional unique products have been introduced to operations to address specific forecast challenges, including the Cooperative Institute for Research in the Atmosphere (CIRA) Layered Precipitable Water, the National Environmental Satellite, Data, and Information Service (NESDIS) Snowfall Rate product, NOAA Unique Combined Atmospheric Processing System (NUCAPS) Soundings, ozone products from the Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder/Advanced Technology Microwave Sounder (CrIS/ATMS), and Infrared Atmospheric Sounding Interferometer (IASI). In addition, new satellite domains have been created to provide forecasters at the NWS Ocean Prediction Center and Weather Prediction Center with better quality imagery at high latitudes. This has led to research projects that are addressing forecast challenges such as tropical to extratropical transition and explosive cyclogenesis. This presentation will provide examples of how the MPS PG has been introducing and integrating

Earth Satellite Population Instability: Underscoring the Need for Debris Mitigation

Science.gov (United States)

Liou, Jer-chyi; Johnson, N. L.

2006-01-01

A recent study by NASA indicates that the implementation of international orbital debris mitigation measures alone will not prevent a significant increase in the artificial Earth satellite population, beginning in the second half of this century. Whereas the focus of the aerospace community for the past 25 years has been on the curtailment of the generation of long-lived orbital debris, active remediation of the current orbital debris population should now be reconsidered to help preserve near-Earth space for future generations. In particular, we show in this paper that even if launch operations were to cease today, the population of space debris would continue to grow. Further, proposed remediation techniques do not appear to offer a viable solution. We therefore recommend that, while the aerospace community maintains the current debris-limiting mission regulations and postmission disposal procedures, future emphasis should be placed on finding new remediation technologies for solving this growing problem. Since the launch of Sputnik 1, space activities have created an orbital debris environment that poses increasing impact risks to existing space systems, including human space flight and robotic missions (1, 2). Currently, more than 9,000 Earth orbiting man-made objects (including many breakup fragments), with a combined mass exceeding 5 million kilograms, are tracked by the US Space Surveillance Network and maintained in the US satellite catalog (3-5). Three accidental collisions between cataloged satellites during the period from late 1991 to early 2005 have already been documented (6), although fortunately none resulted in the creation of large, trackable debris clouds. Several studies conducted during 1991-2001 demonstrated, with assumed future launch rates, the unintended growth potential of the Earth satellite population, resulting from random, accidental collisions among resident space objects (7-13). In some low Earth orbit (LEO) altitude regimes where

Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites

Science.gov (United States)

Afful, Andoh; Opperman, Ben; Steyn, Herman

2016-07-01

Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.

Least reliable bits coding (LRBC) for high data rate satellite communications

Science.gov (United States)

Vanderaar, Mark; Budinger, James; Wagner, Paul

1992-01-01

LRBC, a bandwidth efficient multilevel/multistage block-coded modulation technique, is analyzed. LRBC uses simple multilevel component codes that provide increased error protection on increasingly unreliable modulated bits in order to maintain an overall high code rate that increases spectral efficiency. Soft-decision multistage decoding is used to make decisions on unprotected bits through corrections made on more protected bits. Analytical expressions and tight performance bounds are used to show that LRBC can achieve increased spectral efficiency and maintain equivalent or better power efficiency compared to that of BPSK. The relative simplicity of Galois field algebra vs the Viterbi algorithm and the availability of high-speed commercial VLSI for block codes indicates that LRBC using block codes is a desirable method for high data rate implementations.

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.

R and D limited partnerships (possible applications in advanced communications satellite technology experiment program)

Science.gov (United States)

1985-01-01

Typical R&D limited partnership arrangements, advantages and disadvantages of R&D limited partnership (RDLPs) and antitrust and tax implications are described. A number of typical forms of RDLPs are described that may be applicable for use in stimulating R&D and experimental programs using the advanced communications technology satellite. The ultimate goal is to increase the rate of market penetration of goods and/or services based upon advanced satellite communications technology. The conditions necessary for these RDLP forms to be advantageous are outlined.

Stage-discharge rating curves based on satellite altimetry and modeled discharge in the Amazon basin

Science.gov (United States)

Paris, Adrien; Dias de Paiva, Rodrigo; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stephane; Garambois, Pierre-André; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frederique

2016-05-01

In this study, rating curves (RCs) were determined by applying satellite altimetry to a poorly gauged basin. This study demonstrates the synergistic application of remote sensing and watershed modeling to capture the dynamics and quantity of flow in the Amazon River Basin, respectively. Three major advancements for estimating basin-scale patterns in river discharge are described. The first advancement is the preservation of the hydrological meanings of the parameters expressed by Manning's equation to obtain a data set containing the elevations of the river beds throughout the basin. The second advancement is the provision of parameter uncertainties and, therefore, the uncertainties in the rated discharge. The third advancement concerns estimating the discharge while considering backwater effects. We analyzed the Amazon Basin using nearly one thousand series that were obtained from ENVISAT and Jason-2 altimetry for more than 100 tributaries. Discharge values and related uncertainties were obtained from the rain-discharge MGB-IPH model. We used a global optimization algorithm based on the Monte Carlo Markov Chain and Bayesian framework to determine the rating curves. The data were randomly allocated into 80% calibration and 20% validation subsets. A comparison with the validation samples produced a Nash-Sutcliffe efficiency (Ens) of 0.68. When the MGB discharge uncertainties were less than 5%, the Ens value increased to 0.81 (mean). A comparison with the in situ discharge resulted in an Ens value of 0.71 for the validation samples (and 0.77 for calibration). The Ens values at the mouths of the rivers that experienced backwater effects significantly improved when the mean monthly slope was included in the RC. Our RCs were not mission-dependent, and the Ens value was preserved when applying ENVISAT rating curves to Jason-2 altimetry at crossovers. The cease-to-flow parameter of our RCs provided a good proxy for determining river bed elevation. This proxy was validated

Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

Science.gov (United States)

Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

1993-01-01

Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

Influence of tides in viscoelastic bodies of planet and satellite on the satellite's orbital motion

Science.gov (United States)

Emelyanov, N. V.

2018-06-01

The problem of influence of tidal friction in both planetary and satellite bodies upon satellite's orbital motion is considered. Using the differential equations in satellite's rectangular planetocentric coordinates, the differential equations describing the changes in semimajor axis and eccentricity are derived. The equations in rectangular coordinates were taken from earlier works on the problem. The calcultations carried out for a number of test examples prove that the averaged solutions of equations in coordinates and precise solutions of averaged equations in the Keplerian elements are identical. For the problem of tides raised on planet's body, it was found that, if satellite's mean motion n is equal to 11/18 Ω, where Ω is the planet's angular rotation rate, the orbital eccentricity does not change. This conclusion is in agreement with the results of other authors. It was also found that there is essential discrepancy between the equations in the elements obtained in this paper and analogous equations published by earlier researchers.

A demand assignment control in international business satellite communications network

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo

An experimental system is being developed for use in an international business satellite (IBS) communications network based on demand-assignment (DA) and TDMA techniques. This paper discusses its system design, in particular from the viewpoints of a network configuration, a DA control, and a satellite channel-assignment algorithm. A satellite channel configuration is also presented along with a tradeoff study on transmission rate, HPA output power, satellite resource efficiency, service quality, and so on.

Increased strength of concrete subject to high loading rates

International Nuclear Information System (INIS)

Curbach, M.

1987-01-01

Within the scope of this work various problems are discussed which occur in connection with concrete under high tensile loading rates (e.g. when a plane crashes on a nuclear power plant very high loads occur which act only for a very short time). Particularly the causes for the already frequently noticed increases in strength with increasing loading rates are investigated and also the question whether this increased strength can be taken into account when dimensioning a construction. (MM) [de

Widespread increase of tree mortality rates in the Western United States

Science.gov (United States)

van Mantgem, P.J.; Stephenson, N.L.; Byrne, J.C.; Daniels, L.D.; Franklin, J.F.; Fule, P.Z.; Harmon, M.E.; Larson, A.J.; Smith, Joseph M.; Taylor, A.H.; Veblen, T.T.

2009-01-01

Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.

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

Advanced domestic digital satellite communications systems experiments

Science.gov (United States)

Iso, A.; Izumisawa, T.; Ishida, N.

1984-02-01

The characteristics of advanced digital transmission systems were measured, using newly developed small earth stations and a K-band and C-band communication satellite. Satellite link performance for data, facsimile, video and packet switching information transmission at bit rates ranging from 6.4 kbit/s to 6.3 Mbit/s have been confirmed, using a small K-band earth station and a demand-assignment time division multiple access system. A low-capacity omni-use C-band terminal experiment has verified a telephone channel transmission performance by spread-spectrum multiple access. Single point to multipoint transmission characteristics of the 64 kbit/s data signals from the computer center were tested, using a receive-only 4 GHz earth terminal. Basic satellite link performance was confirmed under clear-sky conditions. Precise satellite orbit and attitude keeping experiments were carried out to obtain precise satellite antenna pointing accuracy for development of K-band earth stations that do not require satellite tracking equipment. Precise station keeping accuracy of 0.02 degrees was obtained.

Use of Advanced Solar Cells for Commercial Communication Satellites

Science.gov (United States)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Military Payloads Hosted on Commercial Satellites: How Can the Space and Missile Systems Center Increase the Number of Commercially Hosted Military Payload Contract Awards

Science.gov (United States)

2015-12-01

in-orbit op- erations averaged between 17 and 22 percent of the cost of the insured satellite; some markets fetched premiums as high as 30 percent.18...coupled device (CCD) visual cameras Echostar-XI & ICO-G1 2008 x2 NAISa US Coast Guard national automatic identification system Orbcomm 2008 IRIS Cisco ...The relocation of a commercial satellite to a market with increased demands could yield a significant return on investment for the commer- cial owner

Peak Satellite-to-Earth Data Rates Derived From Measurements of a 20 Gbps Bread-Board Modem

Science.gov (United States)

Landon, David G.; Simons, Rainee N.; Wintucky, Edwin G.; Sun, Jun Y.; Winn, James S.; Laraway, Stephen A.; McIntire, William K.; Metz, John L.; Smith, Francis J.

2011-01-01

A prototype data link using a Ka-band space qualified, high efficiency 200 W TWT amplifier and a bread-board modem emulator were created to explore the feasibility of very high speed communications in satellite-to-earth applications. Experiments were conducted using a DVB-S2-like waveform with modifications to support up to 20 Gbps through the addition of 128-Quadrature Amplitude Modulation (QAM). Limited by the bandwidth of the amplifier, a constant peak symbol rate of 3.2 Giga-symbols/sec was selected and the modulation order was varied to explore what peak data rate might be supported by an RF link through this amplifier. Using 128-QAM, an implementation loss of 3 dB was observed at 20 Gbps, and the loss decreased as data rate or bandwidth were reduced. Building on this measured data, realistic link budget calculations were completed. Low-Earth orbit (LEO) missions based on this TWTA with reasonable hardware assumptions and antenna sizing are found to be bandwidth-limited, rather than power-limited, making the spectral efficiency of 9/10-rate encoded 128-QAM very attractive. Assuming a bandwidth allocation of 1 GHz, these computations indicate that low-Earth orbit vehicles could achieve data rates up to 5 Gbps-an order of magnitude beyond the current state-of-practice, yet still within the processing power of a current FPGA-based software-defined modem. The measured performance results and a description of the experimental setup are presented to support these conclusions.

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

High power communication satellites power systems study

International Nuclear Information System (INIS)

Josloff, A.T.; Peterson, J.R.

1994-01-01

This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

High power communication satellites power systems study

Science.gov (United States)

Josloff, Allan T.; Peterson, Jerry R.

1995-01-01

This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

Distribution and Variability of Satellite-Derived Signals of Isolated Convection Initiation Events Over Central Eastern China

Science.gov (United States)

Huang, Yipeng; Meng, Zhiyong; Li, Jing; Li, Wanbiao; Bai, Lanqiang; Zhang, Murong; Wang, Xi

2017-11-01

This study combined measurements from the Chinese operational geostationary satellite Fengyun-2E (FY-2E) and ground-based weather radars to conduct a statistical survey of isolated convection initiation (CI) over central eastern China (CEC). The convective environment in CEC is modulated by the complex topography and monsoon climate. From May to August 2010, a total of 1,630 isolated CI signals were derived from FY-2E using a semiautomated method. The formation of these satellite-derived CI signals peaks in the early afternoon and occurs with high frequency in areas with remarkable terrain inhomogeneity (e.g., mountain, water, and mountain-water areas). The high signal frequency areas shift from northwest CEC (dry, high altitude) in early summer to southeast CEC (humid, low altitude) in midsummer along with an increasing monthly mean frequency. The satellite-derived CI signals tend to have longer lead times (the time difference between satellite-derived signal formation and radar-based CI) in the late morning and afternoon than in the early morning and night. During the early morning and night, the distinction between cloud top signatures and background terrestrial radiation becomes less apparent, resulting in delayed identification of the signals and thus short and even negative lead times. A decline in the lead time is observed from May to August, likely due to the increasing cloud growth rate and warm-rain processes. Results show increasing lead times with increasing landscape elevation, likely due to more warm-rain processes over the coastal sea and plain, along with a decreasing cloud growth rate from hill and mountain to the plateau.

Increasing the graduation rates of minority medical students.

Science.gov (United States)

Payne, J L; Nowacki, C M; Girotti, J A; Townsel, J; Plagge, J C; Beckham, T W

1986-05-01

The University of Illinois College of Medicine has operated a program since 1969 to recruit minority students into the college and to increase the graduation rates of these students once they enroll. Known as the Medical Opportunities Program (MOP) until 1978, the program was expanded in 1978 and renamed the Urban Health Program (UHP). The authors of the present paper discuss the results of these programs, particularly the effect of granting minority students delays in completing graduation requirements. The MOP (1969 through 1978) increased graduation rates for minority students from 55 percent for those who graduated on time to 81 percent for both on-time and delayed graduates. Under the first seven years of the UHP (1979 through 1985), more minority students have been offered places, and more have enrolled than in the 10 years of the MOP. The retention rate under the UHP, if it holds, will be higher than that under the MOP. For the combined MOP-UHP period, the retention rate for minority students was 88 percent; 69.8 percent of the graduates were on time, and 30.2 were delayed.

Procedure for determining the optimum rate of increasing shaft depth

Energy Technology Data Exchange (ETDEWEB)

Durov, E.M.

1983-03-01

Presented is an economic analysis of increasing shaft depth during mine modernization. Investigations carried out by the Yuzhgiproshakht Institute are analyzed. The investigations are aimed at determining the optimum shaft sinking rate (the rate which reduces investment to the minimum). The following factors are considered: coal output of a mine (0.9, 1.2, 1.5 and 1.8 Mt/year), depth at which the new mining level is situated (600, 800, 1200, 1400 and 1600 m), four schemes of increasing depth of 2 central shafts (rock hoisting to ground surface, rock hoisting to the existing level, rock haulage to the developed level, rock haulage to the level being developed using a large diameter borehole drilled from the new level to the shaft bottom and enlarged from shaft bottom to the new level), shaft sinking rate (10, 20, 30, 40, 50 and 60 m/month), range of increasing shaft depth (the difference between depth of the shaft before and after increasing its depth by 100, 200, 300 and 400 m). Comparative evaluations show that the optimum shaft sinking rate depends on the scheme for rock hoisting (one of 4 analyzed), range of increasing shaft depth and gas content in coal seams. The optimum shaft sinking rate ranges from 20 to 40 m/month in coal mines with low methane content and from 20 to 30 m/month in gassy coal mines. The planned coal output of a mine does not influence the optimum shaft sinking rate.

STABILITY OF SATELLITES IN CLOSELY PACKED PLANETARY SYSTEMS

International Nuclear Information System (INIS)

Payne, Matthew J.; Holman, Matthew J.; Deck, Katherine M.; Perets, Hagai B.

2013-01-01

We perform numerical integrations of four-body (star, planet, planet, satellite) systems to investigate the stability of satellites in planetary systems with tightly packed inner planets (STIPs). We find that the majority of closely spaced stable two-planet systems can stably support satellites across a range of parameter-space which is only slightly decreased compared to that seen for the single-planet case. In particular, circular prograde satellites remain stable out to ∼0.4 R H (where R H is the Hill radius) as opposed to 0.5 R H in the single-planet case. A similarly small restriction in the stable parameter-space for retrograde satellites is observed, where planetary close approaches in the range 2.5-4.5 mutual Hill radii destabilize most satellites orbits only if a ∼ 0.65 R H . In very close planetary pairs (e.g., the 12:11 resonance) the addition of a satellite frequently destabilizes the entire system, causing extreme close approaches and the loss of satellites over a range of circumplanetary semi-major axes. The majority of systems investigated stably harbored satellites over a wide parameter-space, suggesting that STIPs can generally offer a dynamically stable home for satellites, albeit with a slightly smaller stable parameter-space than the single-planet case. As we demonstrate that multi-planet systems are not a priori poor candidates for hosting satellites, future measurements of satellite occurrence rates in multi-planet systems versus single-planet systems could be used to constrain either satellite formation or past periods of strong dynamical interaction between planets

Effect of digital scrambling on satellite communication links

Science.gov (United States)

Dessouky, K.

1985-01-01

Digital data scrambling has been considered for communication systems using NRZ symbol formats. The purpose is to increase the number of transitions in the data to improve the performance of the symbol synchronizer. This is accomplished without expanding the bandwidth but at the expense of increasing the data bit error rate (BER). Models for the scramblers/descramblers of practical interest are presented together with the appropriate link model. The effects of scrambling on the performance of coded and uncoded links are studied. The results are illustrated by application to the Tracking and Data Relay Satellite System (TDRSS) links. Conclusions regarding the usefulness of scrambling are also given.

Increased heart rate variability during nondirective meditation.

Science.gov (United States)

Nesvold, Anders; Fagerland, Morten W; Davanger, Svend; Ellingsen, Øyvind; Solberg, Erik E; Holen, Are; Sevre, Knut; Atar, Dan

2012-08-01

Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20 min regular rest with eyes closed, thereafter practising Acem meditation for 20 min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p = 0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p = 0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p < 0.001). There was no significant difference in BRS. Respiration and heart rates remained unchanged. Blood pressure increased slightly during meditation. There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

Does sex speed up evolutionary rate and increase biodiversity?

NARCIS (Netherlands)

Melian, Carlos J.; Alonso, David; Allesina, Stefano; Condit, Richard S.; Etienne, Rampal S.

Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious

Energetic electrons at Uranus: Bimodal diffusion in a satellite limited radiation belt

International Nuclear Information System (INIS)

Selesnick, R.S.; Stone, E.C.

1991-01-01

The Voyager 2 cosmic ray experiment observed intense electron fluxes in the middle magnetosphere of Uranus. High counting rates in several of the solid-state detectors precluded in the normal multiple coincidence analysis used for cosmic ray observations, and the authors have therefore performed laboratory measurements of the single-detector response to electrons. These calibrations allow a deconvolution from the counting rate data of the electron energy spectrum between energies of about 0.7 and 2.5 MeV. They present model fits to the differential intensity spectra from observations between L values of 6 and 15. The spectra are well represented by power laws in kinetic energy with spectral indices between 5 and 7. The phase space density at fixed values of the first two adiabatic invariants generally increases with L, indicative of an external source. However, there are also local minima associated with the satellites Ariel and Umbriel, indicating either a local source or an effective source due to nonconservation of the first two adiabatic invariants. For electrons which mirror at the highest magnetic latitudes, the local minimum associated with Ariel is radically displaced from the minimum L of that satellite by ∼0.5. The latitude variation of the satellite absorption efficiency predicts that if satellite losses are replenished primarily by radial diffusion there should be an increasing pitch angle anisotropy with decreasing L. The uniformity in the observed anisotropy outside the absorption regions then suggests that it is maintained by pitch angle diffusion. The effective source due to pitch angle diffusion is insufficient to cause the phase space density minimum associated with Ariel. Model solutions of the simultaneous radial and pitch angle diffusion equation show that the displacement of the high-latitude Ariel signature is also consistent with a larger effective source

Saturn satellites

International Nuclear Information System (INIS)

Ruskol, E.L.

1981-01-01

The characteristics of the Saturn satellites are discussed. The satellites close to Saturn - Janus, Mimas, Enceladus, Tethys, Dione and Rhea - rotate along the circular orbits. High reflectivity is attributed to them, and the density of the satellites is 1 g/cm 3 . Titan is one of the biggest Saturn satellites. Titan has atmosphere many times more powerful than that of Mars. The Titan atmosphere is a peculiar medium with a unique methane and hydrogen distribution in the whole Solar system. The external satellites - Hyperion, Japetus and Phoebe - are poorly investigated. Neither satellite substance density, nor their composition are known. The experimental data on the Saturn rings obtained on the ''Pioneer-11'' and ''Voyager-1'' satellites are presented [ru

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

Incorporating GOES Satellite Photosynthetically Active Radiation (PAR) Retrievals to Improve Biogenic Emission Estimates in Texas

Science.gov (United States)

Zhang, Rui; White, Andrew T.; Pour Biazar, Arastoo; McNider, Richard T.; Cohan, Daniel S.

2018-01-01

This study examines the influence of insolation and cloud retrieval products from the Geostationary Operational Environmental Satellite (GOES) system on biogenic emission estimates and ozone simulations in Texas. Compared to surface pyranometer observations, satellite-retrieved insolation and photosynthetically active radiation (PAR) values tend to systematically correct the overestimation of downwelling shortwave radiation in the Weather Research and Forecasting (WRF) model. The correlation coefficient increases from 0.93 to 0.97, and the normalized mean error decreases from 36% to 21%. The isoprene and monoterpene emissions estimated by the Model of Emissions of Gases and Aerosols from Nature are on average 20% and 5% less, respectively, when PAR from the direct satellite retrieval is used rather than the control WRF run. The reduction in biogenic emission rates using satellite PAR reduced the predicted maximum daily 8 h ozone concentration by up to 5.3 ppbV over the Dallas-Fort Worth (DFW) region on some days. However, episode average ozone response is less sensitive, with a 0.6 ppbV decrease near DFW and 0.3 ppbV increase over East Texas. The systematic overestimation of isoprene concentrations in a WRF control case is partially corrected by using satellite PAR, which observes more clouds than are simulated by WRF. Further, assimilation of GOES-derived cloud fields in WRF improved CAMx model performance for ground-level ozone over Texas. Additionally, it was found that using satellite PAR improved the model's ability to replicate the spatial pattern of satellite-derived formaldehyde columns and aircraft-observed vertical profiles of isoprene.

Larger Optics and Improved Calibration Techniques for Small Satellite Observations with the ERAU OSCOM System

Science.gov (United States)

Bilardi, S.; Barjatya, A.; Gasdia, F.

OSCOM, Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a system capable of providing time-resolved satellite photometry using commercial-off-the-shelf (COTS) hardware and custom tracking and analysis software. This system has acquired photometry of objects as small as CubeSats using a Celestron 11” RASA and an inexpensive CMOS machine vision camera. For satellites with known shapes, these light curves can be used to verify a satellite’s attitude and the state of its deployed solar panels or antennae. While the OSCOM system can successfully track satellites and produce light curves, there is ongoing improvement towards increasing its automation while supporting additional mounts and telescopes. A newly acquired Celestron 14” Edge HD can be used with a Starizona Hyperstar to increase the SNR for small objects as well as extend beyond the limiting magnitude of the 11” RASA. OSCOM currently corrects instrumental brightness measurements for satellite range and observatory site average atmospheric extinction, but calibrated absolute brightness is required to determine information about satellites other than their spin rate, such as surface albedo. A calibration method that automatically detects and identifies background stars can use their catalog magnitudes to calibrate the brightness of the satellite in the image. We present a photometric light curve from both the 14” Edge HD and 11” RASA optical systems as well as plans for a calibration method that will perform background star photometry to efficiently determine calibrated satellite brightness in each frame.

The Satellite Passive-Microwave Record of Sea Ice in the Ross Sea Since Late 1978

Science.gov (United States)

Parkinson, Claire L.

2009-01-01

Satellites have provided us with a remarkable ability to monitor many aspects of the globe day-in and day-out and sea ice is one of numerous variables that by now have quite substantial satellite records. Passive-microwave data have been particularly valuable in sea ice monitoring, with a record that extends back to August 1987 on daily basis (for most of the period), to November 1970 on a less complete basis (again for most of the period), and to December 1972 on a less complete basis. For the period since November 1970, Ross Sea sea ice imagery is available at spatial resolution of approximately 25 km. This allows good depictions of the seasonal advance and retreat of the ice cover each year, along with its marked interannual variability. The Ross Sea ice extent typically reaches a minimum of approximately 0.7 x 10(exp 6) square kilometers in February, rising to a maximum of approximately 4.0 x 10(exp 6) square kilometers in September, with much variability among years for both those numbers. The Ross Sea images show clearly the day-by-day activity greatly from year to year. Animations of the data help to highlight the dynamic nature of the Ross Sea ice cover. The satellite data also allow calculation of trends in the ice cover over the period of the satellite record. Using linear least-squares fits, the Ross Sea ice extent increased at an average rate of 12,600 plus or minus 1,800 square kilometers per year between November 1978 and December 2007, with every month exhibiting increased ice extent and the rates of increase ranging from a low of 7,500 plus or minus 5,000 square kilometers per year for the February ice extents to a high of 20,300 plus or minus 6,100 kilometers per year for the October ice extents. On a yearly average basis, for 1979-2007 the Ross Sea ice extent increased at a rate of 4.8 plus or minus 1.6 % per decade. Placing the Ross Sea in the context of the Southern Ocean as a whole, over the November 1978-December 2007 period the Ross Sea had

Radiation-resistance test on optical fiber for artificial satellite

International Nuclear Information System (INIS)

Morita, Yosuke; Seguchi, Tadao; Mori, Tatsuo; Miyaji, Yuji.

1985-01-01

Radiation resistance of a prototype optical fiber for use in artificial satellites is investigated under a long-term irradiation of gamma rays at relatively low dose rates. The optical fiber tested is composed of a pure silica core and an F-doped cladding. Various aspects of the relations between induced loss and irradiation time are observed and results obtained are discussed. It is generally accepted that a satellite and its equipment should be resistant to a total dose of about 1 x 10 6 rad. In the present test, accordingly, gamma ray irradiation is performed up to a total dose of 1 x 10 6 rad at a dose rate of 1 x 10 4 rad/h (for 100 h), 3 x 10 3 rad/h (333 h) and 1 x 10 3 rad/h (1000 h), and it is shown that the loss induced in this fiber at these dose rates is 23.6 - 27.2, 16.9 - 21.6 and 12.5 - 13.5 dB/km, respectively. On the other hand, it has been reported that the loss induced at the dose rate of 1 x 10 6 rad/h (1 h) is about 600 dB/km, which is much larger than the above values. From these results, the loss at a dose rate of 100 rad/h, which would be expected in a satellite, is estimated at about 10 dB/km. It is concluded that this prototype fiber has a sufficient capability for satellite use with respect to induced loss. (Nogami, K.)

75 FR 81003 - Rate Increase Disclosure and Review

Science.gov (United States)

2010-12-23

... choice of any threshold makes it inevitable that unreasonable rate increases below the threshold will not... in the preliminary justification supplements, and does not conflict with, State laws specifying what...

Increasing Nucleosome Occupancy Is Correlated with an Increasing Mutation Rate so Long as DNA Repair Machinery Is Intact

Science.gov (United States)

Taylor, Jared F.; Khattab, Omar S.; Chen, Yu-Han; Chen, Yumay; Jacobsen, Steven E.; Wang, Ping H.

2015-01-01

Deciphering the multitude of epigenomic and genomic factors that influence the mutation rate is an area of great interest in modern biology. Recently, chromatin has been shown to play a part in this process. To elucidate this relationship further, we integrated our own ultra-deep sequenced human nucleosomal DNA data set with a host of published human genomic and cancer genomic data sets. Our results revealed, that differences in nucleosome occupancy are associated with changes in base-specific mutation rates. Increasing nucleosome occupancy is associated with an increasing transition to transversion ratio and an increased germline mutation rate within the human genome. Additionally, cancer single nucleotide variants and microindels are enriched within nucleosomes and both the coding and non-coding cancer mutation rate increases with increasing nucleosome occupancy. There is an enrichment of cancer indels at the theoretical start (74 bp) and end (115 bp) of linker DNA between two nucleosomes. We then hypothesized that increasing nucleosome occupancy decreases access to DNA by DNA repair machinery and could account for the increasing mutation rate. Such a relationship should not exist in DNA repair knockouts, and we thus repeated our analysis in DNA repair machinery knockouts to test our hypothesis. Indeed, our results revealed no correlation between increasing nucleosome occupancy and increasing mutation rate in DNA repair knockouts. Our findings emphasize the linkage of the genome and epigenome through the nucleosome whose properties can affect genome evolution and genetic aberrations such as cancer. PMID:26308346

Increasing Nucleosome Occupancy Is Correlated with an Increasing Mutation Rate so Long as DNA Repair Machinery Is Intact.

Directory of Open Access Journals (Sweden)

Puya G Yazdi

Full Text Available Deciphering the multitude of epigenomic and genomic factors that influence the mutation rate is an area of great interest in modern biology. Recently, chromatin has been shown to play a part in this process. To elucidate this relationship further, we integrated our own ultra-deep sequenced human nucleosomal DNA data set with a host of published human genomic and cancer genomic data sets. Our results revealed, that differences in nucleosome occupancy are associated with changes in base-specific mutation rates. Increasing nucleosome occupancy is associated with an increasing transition to transversion ratio and an increased germline mutation rate within the human genome. Additionally, cancer single nucleotide variants and microindels are enriched within nucleosomes and both the coding and non-coding cancer mutation rate increases with increasing nucleosome occupancy. There is an enrichment of cancer indels at the theoretical start (74 bp and end (115 bp of linker DNA between two nucleosomes. We then hypothesized that increasing nucleosome occupancy decreases access to DNA by DNA repair machinery and could account for the increasing mutation rate. Such a relationship should not exist in DNA repair knockouts, and we thus repeated our analysis in DNA repair machinery knockouts to test our hypothesis. Indeed, our results revealed no correlation between increasing nucleosome occupancy and increasing mutation rate in DNA repair knockouts. Our findings emphasize the linkage of the genome and epigenome through the nucleosome whose properties can affect genome evolution and genetic aberrations such as cancer.

Increasing inhibitory input increases neuronal firing rate: why and when? Diffusion process cases

Energy Technology Data Exchange (ETDEWEB)

Feng Jianfeng [COGS, Sussex University (United Kingdom)]. E-mail: jf218@cam.ac.uk; Wei Gang [Department of Mathematics, Hong Kong Baptist University, Hong Kong (China)]. E-mail gwei@math.hkbu.edu.hk

2001-09-21

Increasing inhibitory input to single neuronal models, such as the FitzHugh-Nagumo model and the Hodgkin-Huxley model, can sometimes increase their firing rates, a phenomenon which we term inhibition-boosted firing (IBF). Here we consider neuronal models with diffusion approximation inputs, i.e. they share the identical first- and second-order statistics of the corresponding Poisson process inputs. Using the integrate-and-fire model and the IF-FHN model, we explore theoretically how and when IBF can happen. For both models, it is shown that there is a critical input frequency at which the efferent firing rate is identical when the neuron receives purely excitatory inputs or exactly balanced inhibitory and excitatory inputs. When the input frequency is lower than the critical frequency, IBF occurs. (author)

Satellite-Relayed Intercontinental Quantum Network.

Science.gov (United States)

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-19

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Satellite-Relayed Intercontinental Quantum Network

Science.gov (United States)

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-01

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ˜kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

High and Increasing Shoreline Erosion Rates of Thermokarst Lakes Set in Ice-Rich Permafrost Terrain of the Arctic Coastal Plain of Alaska

Science.gov (United States)

Bondurant, A. C.; Arp, C. D.; Jones, B. M.; Shur, Y.; Daanen, R. P.

2017-12-01

Thermokarst lakes are a dominant landform shaping landscapes and impacting permafrost on the Arctic Coastal Plain (ACP) of northern Alaska, a region of continuous permafrost. Here lakes cover greater than 20% of the landscape and drained lake basins cover an additional 50 to 60% of the landscape. The formation, expansion, and drainage of thaw lakes has been described by some researchers as part of a natural cycle that has reworked the ACP landscape during the Holocene. Yet the factors and processes controlling contemporary thermokarst lake expansion remain poorly described. This study focuses on the factors controlling expansion rates of thermokarst lakes in three ACP regions that vary in landscape history, ground-ice content, and lake morphology (i.e. size and depth), as well as evaluating changes through time. Through the use of historical aerial imagery, satellite imagery, and field observations, this study identifies the controlling factors at multiple spatial and temporal scales to better understand the processes relating to thermokarst lake expansion. Studies of 35 lakes across the ACP shows regional differences in expansion rate related to permafrost ice content ranging from an average expansion rate of 0.62 m/yr where ice content is highest ( 86%) to 0.16 m/yr where ice content is lowest (45%-71%). A subset of these lakes analyzed over multiple time periods show increasing rates of erosion, with average rates being 37% higher over the period 1979-2002 (0.73 m/yr) compared to 1948-1979 (0.53 m/yr). These increased rates of erosion have important implications for the regional hydrologic cycle and localized permafrost degradation. Predicting how thermokarst lakes will behave locally and on a landscape scale is increasingly important for managing habitat and water resources and informing models of land-climate interactions in the Arctic.

Small satellite attitude determination based on GPS/IMU data fusion

Energy Technology Data Exchange (ETDEWEB)

Golovan, Andrey [Navigation and Control Laboratory, M.V. Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow (Russian Federation); Cepe, Ali [Department of Applied Mechanics and Control, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2014-12-10

In this paper, we present the mathematical models and algorithms that describe the problem of attitude determination for a small satellite using measurements from three angular rate sensors (ARS) and aiding measurements from multiple GPS receivers/antennas rigidly attached to the platform of the satellite.

Glucagon infusion increases rate of purine synthesis de novo in rat liver

International Nuclear Information System (INIS)

Itakura, Mitsuo; Maeda, Noriaki; Tsuchiya, Masami; Yamashita, Kamejiro

1987-01-01

Based on the parallel increases of glucagon, the second peak of hepatic cAMP, and the rate of purine synthesis de novo in the prereplicative period in regenerating rate liver after a 70% hepatectomy, it was hypothesized that glucagon is responsible for the increased rate of purine synthesis de novo. To test this hypothesis, the effect of glucagon or dibutyryl cAMP infusion on the rate of purine synthesis de novo in rat liver was studied. Glucagon infusion but not insulin or glucose infusion increased the rate of purine synthesis de novo, which was assayed by [ 14 C]glycine or [ 14 C]formate incorporation, by 2.7- to 4.3-fold. Glucagon infusion increased cAMP concentrations by 4.9-fold and 5-phosphoribosyl-1-pyrophosphate concentrations by 1.5-fold in liver but did not change the specific activity of amidophosphoribosyltransferase or purine ribonucleotide concentrations. Dibutyryl cAMP infusion also increased the rate of purine synthesis de novo by 2.2- to 4.0-fold. Because glucagon infusion increased the rate of purine synthesis de novo in the presence of unchanged purine ribonucleotide concentrations, it is concluded that glucagon after infusion or in animals after a 70% hepatectomy is playing an anabolic role to increase the rate of purine synthesis de novo by increasing cAMP and 5-phosphoribosyl-1-pyrophosphate concentrations

Elevated rates of gold mining in the Amazon revealed through high-resolution monitoring.

Science.gov (United States)

Asner, Gregory P; Llactayo, William; Tupayachi, Raul; Luna, Ernesto Ráez

2013-11-12

Gold mining has rapidly increased in western Amazonia, but the rates and ecological impacts of mining remain poorly known and potentially underestimated. We combined field surveys, airborne mapping, and high-resolution satellite imaging to assess road- and river-based gold mining in the Madre de Dios region of the Peruvian Amazon from 1999 to 2012. In this period, the geographic extent of gold mining increased 400%. The average annual rate of forest loss as a result of gold mining tripled in 2008 following the global economic recession, closely associated with increased gold prices. Small clandestine operations now comprise more than half of all gold mining activities throughout the region. These rates of gold mining are far higher than previous estimates that were based on traditional satellite mapping techniques. Our results prove that gold mining is growing more rapidly than previously thought, and that high-resolution monitoring approaches are required to accurately quantify human impacts on tropical forests.

Nesting Bird “Host Funnel” Increases Mosquito-Bird Contact Rate

OpenAIRE

CAILLOUËT, KEVIN A.; RIGGAN, ANNA E.; BULLUCK, LESLEY P.; CARLSON, JOHN C.; SABO, ROY T.

2013-01-01

Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from < 1 mosquito per trap night to 36.2 in the final 2 wk of the nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a “host f...

Increased degradation rate of nitrososureas in media containing carbonate.

Science.gov (United States)

Seidegård, Janeric; Grönquist, Lena; Tuvesson, Helen; Gunnarsson, Per-Olov

2009-01-01

The stability of two nitrosoureas, tauromustine and lomustine, has been investigated in different media and buffers. All media tested, except Leibovitz's L-15 medium, significantly increased the degradation rate of the investigated nitrosoureas at pH 7.4. Sodium bicarbonate seems to be the cause of the observed increase of the degradation rate, since it provides the main buffering capacity of all the media except for Leibovitz's L-15 medium, which is based on phosphate buffer. Other ingredients in the media, such as amino acids, vitamins, and inorganic salts, or the ionic strength of a buffer, did not have any major effect on the degradation rate of the nitrosoureas. These results suggest that media containing carbonated buffer should be avoided when the anti-tumor effect of nitrosoureas is to be investigated in different cell cultures.

"Known Unknowns": Current Questions in Muscle Satellite Cell Biology.

Science.gov (United States)

Cornelison, Ddw

2018-01-01

Our understanding of satellite cells, now known to be the obligate stem cells of skeletal muscle, has increased dramatically in recent years due to the introduction of new molecular, genetic, and technical resources. In addition to their role in acute repair of damaged muscle, satellite cells are of interest in the fields of aging, exercise, neuromuscular disease, and stem cell therapy, and all of these applications have driven a dramatic increase in our understanding of the activity and potential of satellite cells. However, many fundamental questions of satellite cell biology remain to be answered, including their emergence as a specific lineage, the degree and significance of heterogeneity within the satellite cell population, the roles of their interactions with other resident and infiltrating cell types during homeostasis and regeneration, and the relative roles of intrinsic vs extrinsic factors that may contribute to satellite cell dysfunction in the context of aging or disease. This review will address the current state of these open questions in satellite cell biology. © 2018 Elsevier Inc. All rights reserved.

Vibration noise control in laser satellite communication

Science.gov (United States)

Saksonov, Avigdor; Shlomi, Arnon; Kopeika, Norman S.

2001-08-01

Laser satellite communication has become especially attractive in recent years. Because the laser beam width is narrow than in the RF or microwave range, the transmitted optical power may be significantly reduced. This leads to development of miniature communication systems with extremely low power consumption. On the other hand, the laser communication channel is very sensitive to vibrations of the optical platform. These vibrations cause angular noise in laser beam pointing, comparable to the laser beam width. As result, as significant portion of the optical power between transmitter and receiver is lost and the bit error rate is increased. Consequently, vibration noise control is a critical problem in laser satellite communication. The direction of the laser beam is corrected with a fast steering mirror (FSM). In this paper are presented two approaches for the FSM control. One is the feedback control that uses an LQG algorithm. The second is the direct feed- forward control when vibration noise is measured by three orthogonal accelerometers and drives directly the F SM. The performances of each approach are evaluated using MATLAB simulations.

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.

Satellite communications: possibilities and problems

International Nuclear Information System (INIS)

Hine, M.

1986-01-01

Communication links via satellites are becoming available in Europe, both as part of the development of the telephone system and as special services aimed at data traffic. They offer the possibility of speeds between 50 kb/s and 2 Mb/s, without the problems and long term commitments of long distance land lines. Such links are provided by the PTT's as circuits which can be booked for variable periods, and have error rates which can be very low and well controlled. Problems in networking can arise from the satellite delay, particularly if errors occur in the local connections, and from the leased circuit and tariff philosophies of the PTT's. (Auth.)

Global trends in satellite-based emergency mapping

Science.gov (United States)

Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

2016-01-01

Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

Analysis of transmission speed of AX.25 Protocol implemented in satellital earth station UPTC

Directory of Open Access Journals (Sweden)

Oscar Fernando Vera Cely

2015-11-01

Full Text Available One of the important parameters for the proper functioning of satellital ground station projected on Pedagogical and Technological University of Colombia (UPTC is the efficiency in transmission speed on communications protocol. This paper shows the results of analysis of the transmission speed of the AX.25 protocol implemented in the communication system of the satellital ground station UPTC. It begins with a brief description of the implemented hardware; the behavior of the transmission rate is evaluated using a theoretical analysis based on equations to estimate this parameter in the operation of the protocol, then tests are performed using the hardware that the satellital ground station UPTC has and finally, the conclusions are presented. Based on comparison of the theoretical analysis results obtained experimentally, it became apparent that AX.25 protocol efficiency is higher when increasing the number of frames.

Rainfall Imprint on Sea Surface Salinity in the ITCZ: new satellite perspectives

Science.gov (United States)

Boutin, J.; Viltard, N.; Supply, A.; Martin, N.; Vergely, J. L.; Hénocq, C.; Reverdin, G. P.

2016-02-01

The European Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors sea surface salinity (SSS) over the global ocean for more than 5 years since 2010. The MADRAS microwave radiometer carried by the French (CNES) Indian (ISRO) satellite mission Megha-Tropiques sampled the 30° N-30° S region end of 2011 and in 2012, very complementary to other Global Precipitation Measurement(GPM) missions. In tropical regions, SMOS SSS contains a large imprint of atmospheric rainfall, but is also likely affected by oceanographic processes (advection and diffusion). At local and short time scales, Boutin et al. (2013, 2014) have shown that the spatio-temporal variability of SSS is dominated by rainfall as detected by satellite microwave radiometers and have demonstrated a close to linear relationship between SMOS SSS freshening under rain cells and satellite rain rate. The order of magnitude is in remarkable agreement with the theoretical renewal model of Schlussel et al. (1997) and compatible with AQUARIUS SSS observations, as well as with in situ drifters observations although the latter are local and taken at 45cm depth while satellite L-band SSS roughly correspond to the top 1cm depth and are spatially integrated over 43-150km. It is thus expected that the combined information of satellite rain rates and satellite SSS brings new constraints on the precipitation budget. We first look at the consistency between the spatial structures of SMOS SSS decrease and of rain rates derived either from the MADRAS microwave radiometer or from the CMORPH combined products that do not use MADRAS rain rates. This provides an indirect validation of the rain rates estimates. We then investigate the impact of rain history and of wind speed on the observed SMOS freshening. Based on these results, we discuss the precision on various precipitation estimates over 2012 in the ITCZ region and the major sources of uncertainties that the SPURS2 campaign could help to resolve.

ACTS TDMA network control. [Advanced Communication Technology Satellite

Science.gov (United States)

Inukai, T.; Campanella, S. J.

1984-01-01

This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

Next generation satellite communications networks

Science.gov (United States)

Garland, P. J.; Osborne, F. J.; Streibl, I.

The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

NESDIS Blended Rain Rate (RR) Products

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...

Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation.

Science.gov (United States)

Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Elizaveta S; Skorodumova, Elena N; Zhuravleva, Veronika F; Pankratova, Galina V; Volkova, Irina V; Stepanova, Elena V; Porokhovnik, Lev N; Veiko, Natalia N

A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N=88) and tritium β-radiation (N=88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the circulating cfDNA as compared with the cfDNA of non-exposed people (N=109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity. Copyright © 2016 Elsevier B.V. All rights reserved.

Cyber security with radio frequency interferences mitigation study for satellite systems

Science.gov (United States)

Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

2016-05-01

Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

Determination of the N2 recombination rate coefficient in the ionosphere

Science.gov (United States)

Orsini, N.; Torr, D. G.; Brinton, H. C.; Brace, L. H.; Hanson, W. B.; Hoffman, J. H.; Nier, A. O.

1977-01-01

Measurements of aeronomic parameters made by the Atmosphere Explorer-C satellite are used to determine the recombination rate coefficient of N2(+) in the ionosphere. The rate is found to increase significantly with decreasing electron density. Values obtained range from approximately 1.4 x 10 to the -7th to 3.8 x 10 to the -7th cu cm/sec. This variation is explained in a preliminary way in terms of an increase in the rate coefficient with vibrational excitation. Thus, high electron densities depopulate high vibrational levels reducing the effective recombination rate, whereas, low electron densities result in an enhancement in the population of high vibrational levels, thus, increasing the effective recombination rate.

Research of the key technology in satellite communication networks

Science.gov (United States)

Zeng, Yuan

2018-02-01

According to the prediction, in the next 10 years the wireless data traffic will be increased by 500-1000 times. Not only the wireless data traffic will be increased exponentially, and the demand for diversified traffic will be increased. Higher requirements for future mobile wireless communication system had brought huge market space for satellite communication system. At the same time, the space information networks had been greatly developed with the depth of human exploration of space activities, the development of space application, the expansion of military and civilian application. The core of spatial information networks is the satellite communication. The dissertation presented the communication system architecture, the communication protocol, the routing strategy, switch scheduling algorithm and the handoff strategy based on the satellite communication system. We built the simulation platform of the LEO satellites networks and simulated the key technology using OPNET.

The synchronization method for distributed small satellite SAR

Science.gov (United States)

Xing, Lei; Gong, Xiaochun; Qiu, Wenxun; Sun, Zhaowei

2007-11-01

One of critical requirement for distributed small satellite SAR is the trigger time precision when all satellites turning on radar loads. This trigger operation is controlled by a dedicated communication tool or GPS system. In this paper a hardware platform is proposed which has integrated navigation, attitude control, and data handling system together. Based on it, a probabilistic synchronization method is proposed for SAR time precision requirement with ring architecture. To simplify design of transceiver, half-duplex communication way is used in this method. Research shows that time precision is relevant to relative frequency drift rate, satellite number, retry times, read error and round delay length. Installed with crystal oscillator short-term stability 10 -11 magnitude, this platform can achieve and maintain nanosecond order time error with a typical three satellites formation experiment during whole operating process.

The first estimates of global nucleation mode aerosol concentrations based on satellite measurements

Directory of Open Access Journals (Sweden)

M. Kulmala

2011-11-01

Full Text Available Atmospheric aerosols play a key role in the Earth's climate system by scattering and absorbing solar radiation and by acting as cloud condensation nuclei. Satellites are increasingly used to obtain information on properties of aerosol particles with a diameter larger than about 100 nm. However, new aerosol particles formed by nucleation are initially much smaller and grow into the optically active size range on time scales of many hours. In this paper we derive proxies, based on process understanding and ground-based observations, to determine the concentrations of these new particles and their spatial distribution using satellite data. The results are applied to provide seasonal variation of nucleation mode concentration. The proxies describe the concentration of nucleation mode particles over continents. The source rates are related to both regional nucleation and nucleation associated with more restricted sources. The global pattern of nucleation mode particle number concentration predicted by satellite data using our proxies is compared qualitatively against both observations and global model simulations.

Satellite ATM Networks: Architectures and Guidelines Developed

Science.gov (United States)

vonDeak, Thomas C.; Yegendu, Ferit

1999-01-01

An important element of satellite-supported asynchronous transfer mode (ATM) networking will involve support for the routing and rerouting of active connections. Work published under the auspices of the Telecommunications Industry Association (http://www.tiaonline.org), describes basic architectures and routing protocol issues for satellite ATM (SATATM) networks. The architectures and issues identified will serve as a basis for further development of technical specifications for these SATATM networks. Three ATM network architectures for bent pipe satellites and three ATM network architectures for satellites with onboard ATM switches were developed. The architectures differ from one another in terms of required level of mobility, supported data rates, supported terrestrial interfaces, and onboard processing and switching requirements. The documentation addresses low-, middle-, and geosynchronous-Earth-orbit satellite configurations. The satellite environment may require real-time routing to support the mobility of end devices and nodes of the ATM network itself. This requires the network to be able to reroute active circuits in real time. In addition to supporting mobility, rerouting can also be used to (1) optimize network routing, (2) respond to changing quality-of-service requirements, and (3) provide a fault tolerance mechanism. Traffic management and control functions are necessary in ATM to ensure that the quality-of-service requirements associated with each connection are not violated and also to provide flow and congestion control functions. Functions related to traffic management were identified and described. Most of these traffic management functions will be supported by on-ground ATM switches, but in a hybrid terrestrial-satellite ATM network, some of the traffic management functions may have to be supported by the onboard satellite ATM switch. Future work is planned to examine the tradeoffs of placing traffic management functions onboard a satellite as

A small satellite design for deep space network testing and training

Science.gov (United States)

Mcwilliams, Dennis; Slatton, Clint; Norman, Cassidy; Araiza, Joe; Jones, Jason; Tedesco, Mark; Wortman, Michael; Opiela, John; Lett, Pat; Clavenna, Michael

1993-01-01

With the continuing exploration of the Solar System and the reemphasis on Earth focused missions, the need for faster data transmission rates has grown. Ka-band could allow a higher data delivery rate over the current X-band, however the adverse effects of the Earth's atmosphere on Ka are as yet unknown. The Deep Space Network and Jet Propulsion Lab have proposed to launch a small satellite that would simultaneously transmit X and Ka signals to test the viability of switching to Ka-band. The Mockingbird Design Team at the University of Texas at Austin applied small satellite design principles to achieve this objective. The Mockingbird design, named BATSAT, incorporates simple, low-cost systems designed for university production and testing. The BATSAT satellite is a 0.64 m diameter, spherical panel led satellite, mounted with solar cells and omni-directional antennae. The antennae configuration negates the need for active attitude control or spin stabilization. The space-frame truss structure was designed for 11 g launch loads while allowing for easy construction and solar-panel mounting. The communication system transmits at 1 mW by carrying the required Ka and X-band transmitters, as well as an S band transmitter used for DSN training. The power system provides the 8.6 W maximum power requirements via silicon solar arrays and nickel-cadmium batteries. The BATSAT satellite will be lofted into an 1163 km, 70 deg orbit by the Pegasus launch system. This orbit fulfills DSN dish slew rate requirements while keeping the satellite out of the heaviest regions of the Van Allen radiation belts. Each of the three DSN stations capable of receiving Ka-band (Goldstone, Canberra, and Madrid) will have an average of 85 minutes of view-time per day over the satellites ten year design life. Mockingbird Designs hopes that its small satellite design will not only be applicable to this specific mission scenario, but that it could easily be modified for instrument capability for

A small satellite design for deep space network testing and training

Science.gov (United States)

McWilliams, Dennis; Slatton, Clint; Norman, Cassidy; Araiza, Joe; Jones, Jason; Tedesco, Mark; Wortman, Michael; Opiela, John; Lett, Pat; Clavenna, Michael

1993-05-01

With the continuing exploration of the Solar System and the reemphasis on Earth focused missions, the need for faster data transmission rates has grown. Ka-band could allow a higher data delivery rate over the current X-band, however the adverse effects of the Earth's atmosphere on Ka are as yet unknown. The Deep Space Network and Jet Propulsion Lab have proposed to launch a small satellite that would simultaneously transmit X and Ka signals to test the viability of switching to Ka-band. The Mockingbird Design Team at the University of Texas at Austin applied small satellite design principles to achieve this objective. The Mockingbird design, named BATSAT, incorporates simple, low-cost systems designed for university production and testing. The BATSAT satellite is a 0.64 m diameter, spherical panel led satellite, mounted with solar cells and omni-directional antennae. The antennae configuration negates the need for active attitude control or spin stabilization. The space-frame truss structure was designed for 11 g launch loads while allowing for easy construction and solar-panel mounting. The communication system transmits at 1 mW by carrying the required Ka and X-band transmitters, as well as an S band transmitter used for DSN training. The power system provides the 8.6 W maximum power requirements via silicon solar arrays and nickel-cadmium batteries. The BATSAT satellite will be lofted into an 1163 km, 70 deg orbit by the Pegasus launch system. This orbit fulfills DSN dish slew rate requirements while keeping the satellite out of the heaviest regions of the Van Allen radiation belts. Each of the three DSN stations capable of receiving Ka-band (Goldstone, Canberra, and Madrid) will have an average of 85 minutes of view-time per day over the satellites ten year design life. Mockingbird Designs hopes that its small satellite design will not only be applicable to this specific mission scenario, but that it could easily be modified for instrument capability for

Developing status of satellite remote sensing and its application

International Nuclear Information System (INIS)

Zhang Wanliang; Liu Dechang

2005-01-01

This paper has discussed the latest development of satellite remote sensing in sensor resolutions, satellite motion models, load forms, data processing and its application. The authors consider that sensor resolutions of satellite remote sensing have increased largely. Valid integration of multisensors is a new idea and technology of satellite remote sensing in the 21st century, and post-remote sensing application technology is the important part of deeply applying remote sensing information and has great practical significance. (authors)

Satellite imagery in a nuclear age

International Nuclear Information System (INIS)

Baines, P.J.

1998-01-01

Increasingly, high resolution satellite imaging systems are becoming available from multiple and diverse sources with capabilities useful for answering security questions. With increased supply, data availability and data authenticity may be assured. In a commercial market a supplier can ill afford the loss in market share that would result from any falsification of data. Similarly rising competitors willing to sell imagery of national security sites will decrease the tendency to endure self-imposed restrictions on sales of those sites. International organizations operating in the security interests of all nations might also gain preferential access. Costa for imagery will also fall to the point were individuals can afford purchases of satellite images. International organizations will find utility in exploiting imagery for solving international security problems. Housed within international organizations possessing competent staff, procedures, and 'shared destiny' stakes in resolving compliance discrepancies, the use of satellite imagery may provide a degree of stability in a world in which individuals, non-governmental organizations and governments may choose to exploit the available information for political gain. The use of satellite imagery outside these international organizations might not necessarily be aimed at seeking mutually beneficial solutions for international problems

MARKETING STRATEGY TO INCREASE BED OCCUPANCY RATE

Directory of Open Access Journals (Sweden)

Purwaningsih Purwaningsih

2017-07-01

Full Text Available Introduction: A hospital is an institution for health care providing treatment by specialized staff and equipment, more often but not always providing for longer-term patient stays. Today, hospitals are very complex institution, not only survive in dynamic environment but also make a profit based on their services. The aimed of this research was to know marketing mix concept (product, price, place, promotion, people, process and provision of customer service in formulating marketing strategy to increased Bed Occupancy Rate of Obstetric Gynecology Ward 2. Method: The population are health care personnel including midwife, midwife associate, administrator and also client or consumer. The variable were product, price, place, promotion, people, process and provision of customer service. Data were collected by using structured questionnaire. Result: The result showed that product (type of services, infrastructure and facility, relative price, comfortable and safe place, targeted promotion, trained human resources, standard process and provision of customer service are an important aspect to implement strategy marketing to increase Bed Occupancy Rate. Analysis: The result of this study has enlightened the importance of strategy marketing in health care services based on seven principle of marketing mix. Discussion: Implementation of marketing mix in obstetric gynecology ward 2 need to be considered.

Myostatin Suppression of Akirin1 Mediates Glucocorticoid-Induced Satellite Cell Dysfunction

Science.gov (United States)

Dong, Yanjun; Pan, Jenny S.; Zhang, Liping

2013-01-01

Glucocorticoids production is increased in many pathological conditions that are associated with muscle loss, but their role in causing muscle wasting is not fully understood. We have demonstrated a new mechanism of glucocorticoid-induced muscle atrophy: Dexamethasone (Dex) suppresses satellite cell function contributing to the development of muscle atrophy. Specifically, we found that Dex decreases satellite cell proliferation and differentiation in vitro and in vivo. The mechanism involved Dex-induced upregulation of myostatin and suppression of Akirin1, a promyogenic gene. When myostatin was inhibited in Dex-treated mice, Akirin1 expression increased as did satellite cell activity, muscle regeneration and muscle growth. In addition, silencing myostatin in myoblasts or satellite cells prevented Dex from suppressing Akirin1 expression and cellular proliferation and differentiation. Finally, overexpression of Akirin1 in myoblasts increased their expression of MyoD and myogenin and improved cellular proliferation and differentiation, theses improvements were no longer suppressed by Dex. We conclude that glucocorticoids stimulate myostatin which inhibits Akirin1 expression and the reparative functions of satellite cells. These responses attribute to muscle atrophy. Thus, inhibition of myostatin or increasing Akirin1 expression could lead to therapeutic strategies for improving satellite cell activation and enhancing muscle growth in diseases associated with increased glucocorticoid production. PMID:23516508

Myostatin suppression of Akirin1 mediates glucocorticoid-induced satellite cell dysfunction.

Directory of Open Access Journals (Sweden)

Yanjun Dong

Full Text Available Glucocorticoids production is increased in many pathological conditions that are associated with muscle loss, but their role in causing muscle wasting is not fully understood. We have demonstrated a new mechanism of glucocorticoid-induced muscle atrophy: Dexamethasone (Dex suppresses satellite cell function contributing to the development of muscle atrophy. Specifically, we found that Dex decreases satellite cell proliferation and differentiation in vitro and in vivo. The mechanism involved Dex-induced upregulation of myostatin and suppression of Akirin1, a promyogenic gene. When myostatin was inhibited in Dex-treated mice, Akirin1 expression increased as did satellite cell activity, muscle regeneration and muscle growth. In addition, silencing myostatin in myoblasts or satellite cells prevented Dex from suppressing Akirin1 expression and cellular proliferation and differentiation. Finally, overexpression of Akirin1 in myoblasts increased their expression of MyoD and myogenin and improved cellular proliferation and differentiation, theses improvements were no longer suppressed by Dex. We conclude that glucocorticoids stimulate myostatin which inhibits Akirin1 expression and the reparative functions of satellite cells. These responses attribute to muscle atrophy. Thus, inhibition of myostatin or increasing Akirin1 expression could lead to therapeutic strategies for improving satellite cell activation and enhancing muscle growth in diseases associated with increased glucocorticoid production.

Dynamical friction for dark halo satellites: effects of tidal massloss and growing host potential

OpenAIRE

Zhao, HongSheng

2004-01-01

How fast a satellite decays its orbit depends on how slowly its mass is lost by tide. Motivated by inner halo satellite remnants like the Sgr and Omega Cen, we develop fully analytical models to study the orbital decay and tidal massloss of satellites. The orbital decay rate is often severely overestimated if applying the ChandraSekhar's formula without correcting for (a) the evaporation and tidal loss of the satellite and (b) the contraction of satellite orbits due to adiabatic growth of the...

Short-run Distributional Effects of VAT Rate Change: Evidence from a consumption tax rate increase in Japan

OpenAIRE

David CASHIN; UNAYAMA Takashi

2012-01-01

Households will purchase more items than usual prior to a value added tax (VAT) rate increase in order to avoid taxation. Since this type of arbitrage requires resources such as shopping time and storage space, the impacts of tax increases vary across households, which has brought distributional effects in the short-run. Using the case of a consumption tax rate increase in Japan in 1997, we show that households who are non-working, with non-working spouses and residing in larger houses, benef...

Maritime NOx Emissions Over Chinese Seas Derived From Satellite Observations

Science.gov (United States)

Ding, J.; van der A, R. J.; Mijling, B.; Jalkanen, J.-P.; Johansson, L.; Levelt, P. F.

2018-02-01

By applying an inversion algorithm to NOx satellite observations from Ozone Monitoring Instrument, monthly NOx emissions for a 10 year period (2007 to 2016) over Chinese seas are presented for the first time. No effective regulations on NOx emissions have been implemented for ships in China, which is reflected in the trend analysis of maritime emissions. The maritime emissions display a continuous increase rate of about 20% per year until 2012 and slow down to 3% after that. The seasonal cycle of shipping emissions has regional variations, but all regions show lower emissions during winter. Simulations by an atmospheric chemistry transport model show a notable influence of maritime emissions on air pollution over coastal areas, especially in summer. The satellite-derived spatial distribution and the magnitude of maritime emissions over Chinese seas are in good agreement with bottom-up studies based on the Automatic Identification System of ships.

Medical image transmission via communication satellite. Evaluation of bone scintigraphy

International Nuclear Information System (INIS)

Suzuki, Hideki; Inoue, Tomio; Endo, Keigo; Shimamoto, Shigeru.

1995-01-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT 1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical imagings by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6±2.6% via satellite, and 93.2±2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes. (author)

[Medical image transmission via communication satellite: evaluation of bone scintigraphy].

Science.gov (United States)

Suzuki, H; Inoue, T; Endo, K; Shimamoto, S

1995-10-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical images by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6 +/- 2.6% via satellite, and 93.2 +/- 2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes.

Effects of boarding return satellite on antioxidant enzyme activities during germination of hot pepper seed

International Nuclear Information System (INIS)

Li Shuifeng; Wang Bingliang; Guan Xueyu; Zhang Yan

2006-01-01

The effect of boarding return satellite on antioxidant enzyme activities during germination of hot pepper seed was studied. The results showed that the germination potentiality and germination rate of hot pepper seed after boarding return satellite were increased by 3.5% and 5.3%, respectively. During seed germination, soluble protein and MDA contents decreased, however, the SOD activities increased. SOD activity of treated seeds was higher than that of the control especially during the initial period of germination, while the content of soluble and MDA contents were much lower than those of control. The activities of SOD, G-POD, APX and CAT in 13d seedlings of treated seeds were increased by 14.29%, 25.23%, 1.84% and 21.52%, respectively. It was concluded that space flight enhanced antioxidant enzyme activities of seeds and seedlings, which were very important to prevent membrane lipid superoxide. (authors)

Satellite-derived submarine melt rates and mass balance (2011-2015) for Greenland's largest remaining ice tongues

Science.gov (United States)

Wilson, Nat; Straneo, Fiammetta; Heimbach, Patrick

2017-12-01

Ice-shelf-like floating extensions at the termini of Greenland glaciers are undergoing rapid changes with potential implications for the stability of upstream glaciers and the ice sheet as a whole. While submarine melting is recognized as a major contributor to mass loss, the spatial distribution of submarine melting and its contribution to the total mass balance of these floating extensions is incompletely known and understood. Here, we use high-resolution WorldView satellite imagery collected between 2011 and 2015 to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues - Nioghalvfjerdsbræ (79 North Glacier, 79N), Ryder Glacier (RG), and Petermann Glacier (PG). Submarine melt rates under the ice tongues vary considerably, exceeding 50 m a-1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. We compare the total melt rates to the influx of ice to the ice tongue to assess their contribution to the current mass balance. At Petermann Glacier and Ryder Glacier, we find that the combined submarine and aerial melt approximately balances the ice flux from the grounded ice sheet. At Nioghalvfjerdsbræ the total melt flux (14.2 ± 0.96 km3 a-1 w.e., water equivalent) exceeds the inflow of ice (10.2 ± 0.59 km3 a-1 w.e.), indicating present thinning of the ice tongue.

Optical burst switching based satellite backbone network

Science.gov (United States)

Li, Tingting; Guo, Hongxiang; Wang, Cen; Wu, Jian

2018-02-01

We propose a novel time slot based optical burst switching (OBS) architecture for GEO/LEO based satellite backbone network. This architecture can provide high speed data transmission rate and high switching capacity . Furthermore, we design the control plane of this optical satellite backbone network. The software defined network (SDN) and network slice (NS) technologies are introduced. Under the properly designed control mechanism, this backbone network is flexible to support various services with diverse transmission requirements. Additionally, the LEO access and handoff management in this network is also discussed.

Laser technology for high precision satellite tracking

Science.gov (United States)

Plotkin, H. H.

1974-01-01

Fixed and mobile laser ranging stations have been developed to track satellites equipped with retro-reflector arrays. These have operated consistently at data rates of once per second with range precision better than 50 cm, using Q-switched ruby lasers with pulse durations of 20 to 40 nanoseconds. Improvements are being incorporated to improve the precision to 10 cm, and to permit ranging to more distant satellites. These include improved reflector array designs, processing and analysis of the received reflection pulses, and use of sub-nanosecond pulse duration lasers.

Worldwide satellite market demand forecast

Science.gov (United States)

Bowyer, J. M.; Frankfort, M.; Steinnagel, K. M.

1981-01-01

The forecast is for the years 1981 - 2000 with benchmark years at 1985, 1990 and 2000. Two typs of markets are considered for this study: Hardware (worldwide total) - satellites, earth stations and control facilities (includes replacements and spares); and non-hardware (addressable by U.S. industry) - planning, launch, turnkey systems and operations. These markets were examined for the INTELSAT System (international systems and domestic and regional systems using leased transponders) and domestic and regional systems. Forecasts were determined for six worldwide regions encompassing 185 countries using actual costs for existing equipment and engineering estimates of costs for advanced systems. Most likely (conservative growth rate estimates) and optimistic (mid range growth rate estimates) scenarios were employed for arriving at the forecasts which are presented in constant 1980 U.S. dollars. The worldwide satellite market demand forecast predicts that the market between 181 and 2000 will range from $35 to $50 billion. Approximately one-half of the world market, $16 to $20 billion, will be generated in the United States.

Odyssey, an optimized personal communications satellite system

Science.gov (United States)

Rusch, Roger J.

Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry is developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, "bent pipe" transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 Watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km. There are three orbit planes inclined at 55° to the equatorial plane

Increased effects of machining damage in beryllium observed at high strain rates

International Nuclear Information System (INIS)

Beitscher, S.; Brewer, A.W.; Corle, R.R.

1980-01-01

Tensile tests at both low and high strain rates, and also impact shear tests, were performed on a weldable grade powder-source beryllium. Impact energies increased by a factor of 2 to 3 from the as-machined level after etching or annealing. Similar increases in the ductility from machining damage removal were observed from the tensile data at the higher strain rate (10 s -1 ) while an insignificant increase in elongation was measured at the lower strain rate (10 -4 s -1 ). High strain-rate tests appear to be more sensitive and reliable for evaluating machining practice and damage removal methods for beryllium components subjected to sudden loads. 2 tables

78 FR 57101 - Walnuts Grown in California; Increased Assessment Rate

Science.gov (United States)

2013-09-17

... rate currently in effect. The quantity of assessable walnuts for the 2013-14 marketing year is... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 984 [Doc. No. AMS-FV-13-0056; FV13-984-1 PR] Walnuts Grown in California; Increased Assessment Rate AGENCY: Agricultural Marketing...

German telecommunications satellite (Deutscher fernmelde satellit) (DFS-1 and -2)

Science.gov (United States)

Hiendlmeier, G.; Schmeller, H.

1991-01-01

The German Telecommunications Satellite (DFS) Program is to provide telecommunications service for high data rate transmission of text and video data to the Federal Republic of Germany within the 11-14 GHz and 20-30 GHz bands. The space segment of this program is composed of three satellites, DFS-1, DFS-2, and DFS-3, which will be located at 23.5 degrees E longitude of the geostationary orbit. The DFS will be launched from the Center Spatial Guyanis in French Giana on an Ariane launch vehicle. The mission follows the typical injection sequence: parking orbit, transfer orbit, and earth orbit. Attitude maneuvers will be performed to orient the spacecraft prior to Apogee Kick Motor (AKM) firing. After AKM firing, drift phase orbital and attitude maneuvers will be performed to place the spacecraft in its final geostationary position. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. Information is presented in tabular form for the following areas: DSN support, compatibility testing, frequency assignments, telemetry, command, and tracking support responsibilities.

Globally Increased Crop Growth and Cropping Intensity from the Long-Term Satellite-Based Observations

Science.gov (United States)

Chen, Bin

2018-04-01

Understanding the spatiotemporal change trend of global crop growth and multiple cropping system under climate change scenarios is a critical requirement for supporting the food security issue that maintains the function of human society. Many studies have predicted the effects of climate changes on crop production using a combination of filed studies and models, but there has been limited evidence relating decadal-scale climate change to global crop growth and the spatiotemporal distribution of multiple cropping system. Using long-term satellite-derived Normalized Difference Vegetation Index (NDVI) and observed climate data from 1982 to 2012, we investigated the crop growth trend, spatiotemporal pattern trend of agricultural cropping intensity, and their potential correlations with respect to the climate change drivers at a global scale. Results show that 82.97 % of global cropland maximum NDVI witnesses an increased trend while 17.03 % of that shows a decreased trend over the past three decades. The spatial distribution of multiple cropping system is observed to expand from lower latitude to higher latitude, and the increased cropping intensity is also witnessed globally. In terms of regional major crop zones, results show that all nine selected zones have an obvious upward trend of crop maximum NDVI (p impact on the crop growth trend.

Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

Science.gov (United States)

2017-09-01

programmed for eventual integration with the Iridium Network , which is then tested. C. THESIS ORGANIZATION The thesis addresses these questions...NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS by Faisal S. Alshaya September 2017 Co-Advisors: Steven J. Iatrou...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE LEVERAGING THE NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS 5

Topography and Data Mining Based Methods for Improving Satellite Precipitation in Mountainous Areas of China

Directory of Open Access Journals (Sweden)

Ting Xia

2015-07-01

Full Text Available Topography is a significant factor influencing the spatial distribution of precipitation. This study developed a new methodology to evaluate and calibrate the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA products by merging geographic and topographic information. In the proposed method, firstly, the consistency rule was introduced to evaluate the fitness of satellite rainfall with measurements on the grids with and without ground gauges. Secondly, in order to improve the consistency rate of satellite rainfall, genetic programming was introduced to mine the relationship between the gauge rainfall and location, elevation and TMPA rainfall. The proof experiment and analysis for the mean annual satellite precipitation from 2001–2012, 3B43 (V7 of TMPA rainfall product, was carried out in eight mountainous areas of China. The result shows that the proposed method is significant and efficient both for the assessment and improvement of satellite precipitation. It is found that the satellite rainfall consistency rates in the gauged and ungauged grids are different in the study area. In addition, the mined correlation of location-elevation-TMPA rainfall can noticeably improve the satellite precipitation, both in the context of the new criterion of the consistency rate and the existing criteria such as Bias and RMSD. The proposed method is also efficient for correcting the monthly and mean monthly rainfall of 3B43 and 3B42RT.

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.

Satellite communications - Intelsat and global patterns

Science.gov (United States)

Astrain, S.

1983-10-01

The global pattern of mankind's population growth is examined, taking into account the exponential increase in population which began only in the 17th century. As world population has grown, trade has increased, and transportation and communications have become vitally important. A revolution in global communications was initiated when Intelsat launched the first international communications satellite, 'Early Bird', in April 1965. Since April 1965, a tremendous development in global communications by means of satellites has taken place. The Intelsat VI satellite will have a capacity of 36,000 telephone circuits plus 2 TV channels, while the capacity of Early Bird was only 240 telephone circuits. Today, Intelsat is truly an international organization which includes 108 member countries. Attention is given to the particular importance of the Intelsat services to the developing countries, the exploration of new technologies and system concepts, and the extension of services to those portions of the global village which have remained electronically isolated.

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.

Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

Energy Technology Data Exchange (ETDEWEB)

Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Ershova, Elizaveta S. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation); Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Veiko, Natalia N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation)

2016-09-15

circulating cfDNA as compared with the cfDNA of non-exposed people (N = 109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity.

Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

International Nuclear Information System (INIS)

Korzeneva, Inna B.; Kostuyk, Svetlana V.; Ershova, Elizaveta S.; Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V.; Porokhovnik, Lev N.; Veiko, Natalia N.

2016-01-01

circulating cfDNA as compared with the cfDNA of non-exposed people (N = 109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity.

Tracking and Data Relay Satellite System user impact and network compatibility study. [antenna design and telecommunication links

Science.gov (United States)

1973-01-01

The report contains data on antenna configurations for the low data rate users of the Tracking and Data Relay Satellite System (TDRSS). It treats the coverage and mutual visibility considerations between the user satellites and the relay satellites and relates these considerations to requirements of antenna beamwidth and fractional user orbital coverage. A final section includes user/TDRS telecommunication link budgets and forward and return link data rate tradeoffs.

FOP is a centriolar satellite protein involved in ciliogenesis.

Directory of Open Access Journals (Sweden)

Joanna Y Lee

Full Text Available Centriolar satellites are proteinaceous granules that are often clustered around the centrosome. Although centriolar satellites have been implicated in protein trafficking in relation to the centrosome and cilium, the details of their function and composition remain unknown. FOP (FGFR1 Oncogene Partner is a known centrosome protein with homology to the centriolar satellite proteins FOR20 and OFD1. We find that FOP partially co-localizes with the satellite component PCM1 in a cell cycle-dependent manner, similarly to the satellite and cilium component BBS4. As for BBS4, FOP localization to satellites is cell cycle dependent, with few satellites labeled in G1, when FOP protein levels are lowest, and most labeled in G2. FOP-FGFR1, an oncogenic fusion that causes a form of leukemia called myeloproliferative neoplasm, also localizes to centriolar satellites where it increases tyrosine phosphorylation. Depletion of FOP strongly inhibits primary cilium formation in human RPE-1 cells. These results suggest that FOP is a centriolar satellite cargo protein and, as for several other satellite-associated proteins, is involved in ciliogenesis. Localization of the FOP-FGFR1 fusion kinase to centriolar satellites may be relevant to myeloproliferative neoplasm disease progression.

NASA/DARPA advanced communications technology satellite project for evaluation of telemedicine outreach using next-generation communications satellite technology: Mayo Foundation participation.

Science.gov (United States)

Gilbert, B K; Mitchell, M P; Bengali, A R; Khandheria, B K

1999-08-01

To describe the development of telemedicine capabilities-application of remote consultation and diagnostic techniques-and to evaluate the feasibility and practicality of such clinical outreach to rural and underserved communities with limited telecommunications infrastructures. In 1992, Mayo Foundation (Rochester, Minn, Jacksonville, Fla, and Scottsdale, Ariz), the National Aeronautics and Space Administration, and the Defense Advanced Research Projects Agency collaborated to create a complex network of fiberoptic landlines, video recording systems, satellite terminals, and specially developed data translators linking Mayo sites with other locations in the continental United States on an on-demand basis. The purpose was to transmit data via the asynchronous transfer mode (ATM) digital communications protocol over the Advanced Communications Technology Satellite. The links were intended to provide a conduit for transmission of data for patient-specific consultations between physicians, evaluation of medical imagery, and medical education for clinical staffs at remote sites. Low-data-rate (LDR) experiments went live late in 1993. Mayo Clinic Rochester successfully provided medical consultation and services to 2 small regional medical facilities. High-data-rate (HDR) experiments included studies of remote digital echocardiography, store-and-forward telemedicine, cardiac catheterization, and teleconsultation for congenital heart disease. These studies combined landline data transmission with use of the satellite. The complexity of the routing paths and network components, immaturity of available software, and inexperience with existing telecommunications caused significant study delays. These experiments demonstrated that next-generation satellite technology can provide batch and real-time imagery for telemedicine. The first-generation of the ATM and satellite network technology used in these experiments created several technical problems and inconveniences that should

The molecular responses of skeletal muscle satellite cells to continuous expression of IGF-1: implications for the rescue of induced muscular atrophy in aged rats

Science.gov (United States)

Chakravarthy, M. V.; Booth, F. W.; Spangenburg, E. E.

2001-01-01

Approximately 50% of humans older than 85 years have physical frailty due to weak skeletal muscles. This indicates a need for determining mechanisms to combat this problem. A critical cellular factor for postnatal muscle growth is a population of myogenic precursor cells called satellite cells. Given the complex process of sarcopenia, it has been postulated that, at some point in this process, a limited satellite cell proliferation potential could become rate-limiting to the regrowth of old muscles. It is conceivable that if satellite cell proliferative capacity can be maintained or enhanced with advanced age, sarcopenia could potentially be delayed or prevented. Therefore, the purposes of this paper are to describe whether IGF-I can prevent muscular atrophy induced by repeated cycles of hindlimb immobilization, increase the in vitro proliferation in satellite cells from these muscles and, if so, the molecular mechanisms by which IGF-I mediates this increased proliferation. Our results provide evidence that IGF-I can enhance aged muscle regrowth possibly through increased satellite cell proliferation. The results also suggest that IGF-I enhances satellite cell proliferation by decreasing the cell cycle inhibitor, p27Kip1, through the PI3'-K/Akt pathway. These data provide molecular evidence for IGF-I's rescue effect upon aging-associated skeletal muscle atrophy.

New Channel Coding Methods for Satellite Communication

Directory of Open Access Journals (Sweden)

J. Sebesta

2010-04-01

Full Text Available This paper deals with the new progressive channel coding methods for short message transmission via satellite transponder using predetermined length of frame. The key benefits of this contribution are modification and implementation of a new turbo code and utilization of unique features with applications of methods for bit error rate estimation and algorithm for output message reconstruction. The mentioned methods allow an error free communication with very low Eb/N0 ratio and they have been adopted for satellite communication, however they can be applied for other systems working with very low Eb/N0 ratio.

Sequential improvements in organ procurement increase the organ donation rate.

Science.gov (United States)

Billeter, Adrian T; Sklare, Seth; Franklin, Glen A; Wright, Jerry; Morgan, Gary; O'Flynn, Paul E; Polk, Hiram C

2012-11-01

Organ demand exceeds availability of transplantable organs. Organ procurement continues to suffer from failures to identify potential donors, inability to obtain consent for donation, as well as failures to retrieve certain organs as donor demographics change. The purpose of this article is to propose how sequentially introduced measures can increase organ donation rates as well as improve organ procurement. We analysed the effect of stepwise improvements in the organ procurement process patients in a university-based surgical intensive care unit over a 20-year period. We related newly introduced measures in the organ retrieval process with changes in donation rates. We specifically targeted these three main steps in the donation process: donor identification, conversion of potential donors to actual donors, and organ protection during the procurement process. Finally, we assessed the effect of the same measures on organ procurement after introduction in other hospitals of the same organ procurement region. Introduction of quality improvement steps increased all of the observed parameters. The number of organ donors was stabilised due to a better identification of potential donors, a major increase in conversion from potential to actual donors, and an increase in extended criteria donor. Improvements in organ protection led to higher rates of organs transplanted per donor and increased recovery of lungs and hearts despite increasing donor age. The same measures were introduced successfully in other hospitals in our organ procurement region. Sequential improvements in organ procurement can increase the yield of retrieved organs. The same measures can be applied to other hospitals and lead to comparable improvements in organ donation. Published by Elsevier Ltd.

Rising Tide II: Do Black Students Benefit as Grad Rates Increase?

Science.gov (United States)

Nichols, Andrew Howard; Eberle-Sudré, Kimberlee; Welch, Meredith

2016-01-01

"Rising Tide II: Do Black Students Benefit as Grad Rates Increase?" looks at a decade of graduation rates for African American students at four-year, public institutions that improved student success during the past decade. It shows that while a majority (almost 70 percent) of institutions we examined improved graduation rates for black…

A dichotomy in satellite quenching around L* galaxies

Science.gov (United States)

Phillips, John I.; Wheeler, Coral; Boylan-Kolchin, Michael; Bullock, James S.; Cooper, Michael C.; Tollerud, Erik J.

2014-01-01

We examine the star formation properties of bright (˜0.1 L*) satellites around isolated ˜L* hosts in the local Universe using spectroscopically confirmed systems in the Sloan Digital Sky Survey Data Release 7. Our selection method is carefully designed with the aid of N-body simulations to avoid groups and clusters. We find that satellites are significantly more likely to be quenched than a stellar mass-matched sample of isolated galaxies. Remarkably, this quenching occurs only for satellites of hosts that are themselves quenched: while star formation is unaffected in the satellites of star-forming hosts, satellites around quiescent hosts are more than twice as likely to be quenched than stellar-mass-matched field samples. One implication of this is that whatever shuts down star formation in isolated, passive L* galaxies also play at least an indirect role in quenching star formation in their bright satellites. The previously reported tendency for `galactic conformity' in colour/morphology may be a by-product of this host-specific quenching dichotomy. The Sérsic indices of quenched satellites are statistically identical to those of field galaxies with the same specific star formation rates, suggesting that environmental and secular quenching give rise to the same morphological structure. By studying the distribution of pairwise velocities between the hosts and satellites, we find dynamical evidence that passive host galaxies reside in dark matter haloes that are ˜45 per cent more massive than those of star-forming host galaxies of the same stellar mass. We emphasize that even around passive hosts, the mere fact that galaxies become satellites does not typically result in star formation quenching: we find that only ˜30 per cent of ˜0.1L* galaxies that fall in from the field are quenched around passive hosts, compared with ˜0 per cent around star-forming hosts.

Nesting bird "host funnel" increases mosquito-bird contact rate.

Science.gov (United States)

Caillouët, Kevin A; Riggan, Anna E; Bulluck, Lesley P; Carlson, John C; Sabo, Roy T

2013-03-01

Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a "host funnel," concentrating host-seeking mosquitoes to the few remaining nestlings. The relative abundance of mosquitoes collected by the NMT suggests that significantly more Aedes albopictus (Skuse) and Culex pipiens (L.) /restuans (Theobald) sought nesting bird bloodmeals than were predicted by their relative abundances in CO2-baited Centers for Disease Control and Prevention light and gravid traps. Culex salinarius (Coquillett) and Culex erraticus Dyar and Knab were collected in NMTs in proportion to their relative abundances in the generic traps. Temporal host funnels and nesting bird host specificity may enhance arbovirus amplification and explain observed West Nile virus and St. Louis encephalitis virus amplification periods.

The Intertemporal Substitution and Income Effects of a VAT Rate Increase: Evidence from Japan

OpenAIRE

David CASHIN; UNAYAMA Takashi

2011-01-01

One of the biggest political issues in Japan is an increase in the rate of value added tax (VAT). In this paper, we evaluate its impact on household expenditure, using Japan's April 1997 VAT rate increase from three to five percent as a case study. A rate increase induces price hikes, and provided this increase in price levels is anticipated, households should engage in intertemporal substitution of purchases. In addition, if households are not compensated for the rate increase, it has the po...

Interpretation of Spectrometric Measurements of Active Geostationary Satellites

Science.gov (United States)

Bedard, D.; Wade, G.

2014-09-01

Over 5000 visible near-infrared (VNIR) spectrometric measurements of active geostationary satellites have been collected with the National Research Council (NRC) 1.8m Plaskett telescope located at the Dominion Astrophysical Observatory (DAO) in Victoria, Canada. The objective of this ongoing experiment is to study how reflectance spectroscopy can be used to reliably identify specific material types on the surface of artificial Earth-orbiting objects. Active geostationary satellites were selected as the main subjects for this experiment since their orientation is stable and can be estimated to a high-level of confidence throughout a night of observation. Furthermore, for most geostationary satellites, there is a wide variety of sources that can provide some level of information as to their external surface composition. Notwithstanding the high number of measurements that have been collected to date, it was assumed that the experimenters would have a much greater success rate in material identification given the choice experimental subjects. To date, only the presence of aluminum has been confidently identified in some of the reflectance spectra that have been collected. Two additional material types, namely photovoltaic cells and polyimide film, the first layer of multi-layer insulation (MLI), have also been possibly identified. However uncertainties in the reduced spectral measurements prevent any definitive conclusion with respect to these materials at this time. The surprising lack of results with respect to material identification have forced the experimenters to use other data interpretation methods to characterize the spectral scattering characteristics of the studied satellites. The results from this study have already led to improvements in the ways that reflectance spectra from spacecraft are collected and analysed. Equally important, the data interpretation techniques elaborated over the course of this experiment will also serve to increase the body of

Satellite combined heat and power plants and their legal autonomy

International Nuclear Information System (INIS)

Loibl, Helmut

2014-01-01

Since the landmark decision by the German Court of Justice concerning the term ''plant'' in the context of biogas plants it should be clear beyond doubt that satellite combined heat and power plants (CHPs) are legally autonomous plants pursuant to Para. 3 No. 1 of the Renewable Energy Law (EEG). What has yet to be finally resolved are the conditions under which satellite CHPs are to be regarded as autonomous. This will be a question of distance on the one hand and of operation autonomy on the other. In the individual case both these factors will have to be assessed from the perspective of an average objective, informed citizen. To the extent that its heat and electricity are being utilised in a meaningful manner, the plant's autonomy will be beyond doubt, at least in operational terms. Regarding the remuneration to be paid for satellite CHPs the only case requiring special consideration is when a CHP falls under the EEG of 2012. In this case Para. 1 Section 1 Sentence 2 EEG provides that the remuneration for the CHP in question is to be calculated as if there was a single overall plant. To the extent that none of the CHPs fall under the EEG of 2012, the ruling remains that there is a separate entitlement to remuneration for each satellite CHP. This also holds in cases where satellite CHPs that were commissioned after 1 January 2012 are relocated. When a satellite CHP is replaced by a new one, the rate and duration of remuneration remain unchanged. However, when a new satellite CHP is added to an existing satellite CHP via a gas collector line it is to be treated according to the decisions of the Federal Court of Justice concerning biogas plant extensions: It falls under the law that applies to the existing CHP and has an entitlement to a new minimum remuneration period, albeit subject to the degression rate provided by the EEG version in question.

Increased traffic accident rates associated with shale gas drilling in Pennsylvania.

Science.gov (United States)

Graham, Jove; Irving, Jennifer; Tang, Xiaoqin; Sellers, Stephen; Crisp, Joshua; Horwitz, Daniel; Muehlenbachs, Lucija; Krupnick, Alan; Carey, David

2015-01-01

We examined the association between shale gas drilling and motor vehicle accident rates in Pennsylvania. Using publicly available data on all reported vehicle crashes in Pennsylvania, we compared accident rates in counties with and without shale gas drilling, in periods with and without intermittent drilling (using data from 2005 to 2012). Counties with drilling were matched to non-drilling counties with similar population and traffic in the pre-drilling period. Heavily drilled counties in the north experienced 15-23% higher vehicle crash rates in 2010-2012 and 61-65% higher heavy truck crash rates in 2011-2012 than control counties. We estimated 5-23% increases in crash rates when comparing months with drilling and months without, but did not find significant effects on fatalities and major injury crashes. Heavily drilled counties in the southwest showed 45-47% higher rates of fatal and major injury crashes in 2012 than control counties, but monthly comparisons of drilling activity showed no significant differences associated with drilling. Vehicle accidents have measurably increased in conjunction with shale gas drilling. Copyright © 2014. Published by Elsevier Ltd.

Advanced Communications Technology Satellite (ACTS) and potential system applications

Science.gov (United States)

Wright, David L.; Balombin, Joseph R.; Sohn, Philip Y.

1990-01-01

A description of the advanced communications technology satellite (ACTS) system is given with special emphasis on the communication characteristics. Potential satellite communications scenarios, including future operational ACTS-like satellite systems, are discussed. The description of the ACTS system updates previously published ACTS system references. Detailed information on items such as experimental ground stations is presented. The potential services can be generically described as voice, video, and data services. The implementation of these services on future operational ACTS-like systems can lead to unique quality, flexibility, and capacity characteristics at lower service costs. The specific service applications that could be supported range from low to high data rates and include both domestic and international applications.

Does sex speed up evolutionary rate and increase biodiversity?

Science.gov (United States)

Melián, Carlos J; Alonso, David; Allesina, Stefano; Condit, Richard S; Etienne, Rampal S

2012-01-01

Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious mutations, and adaptation to heterogeneous environments. Slower rates with sex have been attributed to removal of major genetic rearrangements, the cost of finding a mate, vulnerability to predation, and exposure to sexually transmitted diseases. Whether sex speeds or slows evolution, the connection between reproductive mode, the evolutionary rate, and species diversity remains largely unexplored. Here we present a spatially explicit model of ecological and evolutionary dynamics based on DNA sequence change to study the connection between mutation, speciation, and the resulting biodiversity in sexual and asexual populations. We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity. In this way, sex can reduce diversity relative to asexual populations, because it leads to a higher rate of production of new species, but with lower abundances. Our results show that reproductive mode and the mechanisms underlying it can alter the link between mutation, evolutionary rate, speciation and biodiversity and we suggest that a high rate of evolution may not be required to yield high biodiversity.

Increasing rate of middle ear ventilation tube insertion in children in denmark

DEFF Research Database (Denmark)

Djurhuus, Bjarki Ditlev; Skytthe, Axel; Christensen, Kaare

2014-01-01

ventilation tube insertions distributed among 269,459 different children were identified. From 1997 to 2010 the age standardized incidence rate in 0-15-year-olds increased from 26 to 40 per 1000 person years with an estimated annual increase of 2.0% (95% confidence interval 1.9-2.1%). The largest increase...... in incidence rate was found in 1-year-olds with an annual increase of 4.5% (95% confidence interval 4.4-4.6%). Age-specific incidence rates remained at maximum around the age of 14 months throughout the period. The cumulative incidence proportion for the 2010 birth cohort by the time they reach the age of 5......OBJECTIVE: To study the incidence rates of middle ear ventilation tube insertion in children aged 0 to 15 years in Denmark from 1997 to 2010. METHODS: Using two national registers, the Danish National Health Service Register and the Danish National Patient Register, practically all cases of middle...

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....

Human Artificial Chromosomes with Alpha Satellite-Based De Novo Centromeres Show Increased Frequency of Nondisjunction and Anaphase Lag

OpenAIRE

Rudd, M. Katharine; Mays, Robert W.; Schwartz, Stuart; Willard, Huntington F.

2003-01-01

Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fu...

Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

Science.gov (United States)

Smith, W. Kolby; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y; Running, Steven W.

2015-01-01

Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

A Survey of Satellite Communications System Vulnerabilities

National Research Council Canada - National Science Library

Steinberger, Jessica A

2008-01-01

The U.S. military's increasing reliance on commercial and military communications satellites to enable widely-dispersed, mobile forces to communicate makes these space assets increasingly vulnerable to attack by adversaries...

Myostatin signals through Pax7 to regulate satellite cell self-renewal

International Nuclear Information System (INIS)

McFarlane, Craig; Hennebry, Alex; Thomas, Mark; Plummer, Erin; Ling, Nicholas; Sharma, Mridula; Kambadur, Ravi

2008-01-01

Myostatin, a Transforming Growth Factor-beta (TGF-β) super-family member, has previously been shown to negatively regulate satellite cell activation and self-renewal. However, to date the mechanism behind Myostatin function in satellite cell biology is not known. Here we show that Myostatin signals via a Pax7-dependent mechanism to regulate satellite cell self-renewal. While excess Myostatin inhibited Pax7 expression via ERK1/2 signaling, an increase in Pax7 expression was observed following both genetic inactivation and functional antagonism of Myostatin. As a result, we show that either blocking or inactivating Myostatin enhances the partitioning of the fusion-incompetent self-renewed satellite cell lineage (high Pax7 expression, low MyoD expression) from the pool of actively proliferating myogenic precursor cells. Consistent with this result, over-expression of Pax7 in C2C12 myogenic cells resulted in increased self-renewal through a mechanism which slowed both myogenic proliferation and differentiation. Taken together, these results suggest that increased expression of Pax7 promotes satellite cell self-renewal, and furthermore Myostatin may control the process of satellite cell self-renewal through regulation of Pax7. Thus we speculate that, in addition to the intrinsic factors (such as Pax7), extrinsic factors both positive and negative in nature, will play a major role in determining the stemness of skeletal muscle satellite cells

Diurnal cycle and seasonal variation of cloud cover over the Tibetan Plateau as determined from Himawari-8 new-generation geostationary satellite data.

Science.gov (United States)

Shang, Huazhe; Letu, Husi; Nakajima, Takashi Y; Wang, Ziming; Ma, Run; Wang, Tianxing; Lei, Yonghui; Ji, Dabin; Li, Shenshen; Shi, Jiancheng

2018-01-18

Analysis of cloud cover and its diurnal variation over the Tibetan Plateau (TP) is highly reliant on satellite data; however, the accuracy of cloud detection from both polar-orbiting and geostationary satellites over this area remains unclear. The new-generation geostationary Himawari-8 satellites provide high-resolution spatial and temporal information about clouds over the Tibetan Plateau. In this study, the cloud detection of MODIS and AHI is investigated and validated against CALIPSO measurements. For AHI and MODIS, the false alarm rate of AHI and MODIS in cloud identification over the TP was 7.51% and 1.94%, respectively, and the cloud hit rate was 73.55% and 80.15%, respectively. Using hourly cloud-cover data from the Himawari-8 satellites, we found that at the monthly scale, the diurnal cycle in cloud cover over the TP tends to increase throughout the day, with the minimum and maximum cloud fractions occurring at 10:00 a.m. and 18:00 p.m. local time. Due to the limited time resolution of polar-orbiting satellites, the underestimation of MODIS daytime average cloud cover is approximately 4.00% at the annual scale, with larger biases during the spring (5.40%) and winter (5.90%).

50 CFR 260.81 - Readjustment and increase in hourly rates of fees.

Science.gov (United States)

2010-10-01

... of fees. 260.81 Section 260.81 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL... Certification of Establishments and Fishery Products for Human Consumption Fees and Charges § 260.81 Readjustment and increase in hourly rates of fees. (a) When Federal Pay Act increases occur, the hourly rates...

Transient HIF2A inhibition promotes satellite cell proliferation and muscle regeneration.

Science.gov (United States)

Xie, Liwei; Yin, Amelia; Nichenko, Anna S; Beedle, Aaron M; Call, Jarrod A; Yin, Hang

2018-03-13

The remarkable regeneration capability of skeletal muscle depends on coordinated proliferation and differentiation of satellite cells. The self-renewal of satellite cells is critical for long-term maintenance of muscle regeneration potential. Hypoxia profoundly affects the proliferation, differentiation, and self-renewal of cultured myoblasts. However, the physiological relevance of hypoxia and hypoxia signaling in satellite cells in vivo remains largely unknown. Here, we report that satellite cells are in an intrinsic hypoxic state in vivo and express hypoxia-inducible factor 2A (HIF2A). HIF2A promotes the stemness and long-term homeostatic maintenance of satellite cells by maintaining the quiescence, increasing the self-renewal and blocking the myogenic differentiation of satellite cells. HIF2A stabilization in satellite cells cultured under normoxia augmented their engraftment potential in regenerative muscle. Reversely, HIF2A ablation led to the depletion of satellite cells and the consequent regenerative failure in the long-term. In contrast, transient pharmacological inhibition of HIF2A accelerated muscle regeneration by increasing satellite cell proliferation and differentiation. Mechanistically, HIF2A induces the quiescence/self-renewal of satellite cells by binding the promoter of Spry1 gene and activating Spry1 expression. These findings suggest that HIF2A is a pivotal mediator of hypoxia signaling in satellite cells and may be therapeutically targeted to improve muscle regeneration.

Small Satellite Passive Magnetic Attitude Control

Science.gov (United States)

Gerhardt, David T.

Passive Magnetic Attitude Control (PMAC) is capable of aligning a satellite within 5 degrees of the local magnetic field at low resource cost, making it ideal for a small satellite. However, simulation attempts to date have not been able to predict the attitude dynamics at a level sufficient for mission design. Also, some satellites have suffered from degraded performance due to an incomplete understanding of PMAC system design. This dissertation alleviates these issues by discussing the design, inputs, and validation of PMAC systems for small satellites. Design rules for a PMAC system are defined using the Colorado Student Space Weather Experiment (CSSWE) CubeSat as an example. A Multiplicative Extended Kalman Filter (MEKF) is defined for the attitude determination of a PMAC satellite without a rate gyro. After on-orbit calibration of the off-the-shelf magnetometer and photodiodes and an on-orbit fit to the satellite magnetic moment, the MEKF regularly achieves a three sigma attitude uncertainty of 4 degrees or less. CSSWE is found to settle to the magnetic field in seven days, verifying its attitude design requirement. A Helmholtz cage is constructed and used to characterize the CSSWE bar magnet and hysteresis rods both individually and in the flight configuration. Fitted parameters which govern the magnetic material behavior are used as input to a PMAC dynamics simulation. All components of this simulation are described and defined. Simulation-based dynamics analysis shows that certain initial conditions result in abnormally decreased settling times; these cases may be identified by their dynamic response. The simulation output is compared to the MEKF output; the true dynamics are well modeled and the predicted settling time is found to possess a 20 percent error, a significant improvement over prior simulation.

The next generation of Palapa satellite (Palapa-C)

Science.gov (United States)

Setiawan, Bambang

The Indonesian Palapa Communication Satellite System was established in Aug. 1976 when the first satellite of Palapa A series (Palapa A1) began operation. The system is owned and operated by PT. Telekomunikasi Indonesia (Telkom), which is a state owned company. The purpose of the system was to unify the telecommunications of the nation. Many years of operation have shown that satellite technology is the best solution for improving telecommunications in Indonesia. The system was started with 2 (two) satellites, each with 12 transponders (for a total of 24), and 40 earth stations. Now the system has 3 (three) satellites, each with 24 transponders (for a total of 72 transponders), and thousands of earth stations. The services have been extended to satisfy the requirements of the region as well as the original objectives. The use of satellite transponders in the region is increasing rapidly. In the next ten years, opportunities in the satellite communications business will become even more attractive. The next generation Palapa-C will incorporate improvements in capacity, quality, and coverage. The new frequency bands (ku- and Extended-C Band) will be used to meet the new transponder capacity requirements.

GLOBALLY INCREASED CROP GROWTH AND CROPPING INTENSITY FROM THE LONG-TERM SATELLITE-BASED OBSERVATIONS

Directory of Open Access Journals (Sweden)

B. Chen

2018-04-01

Full Text Available Understanding the spatiotemporal change trend of global crop growth and multiple cropping system under climate change scenarios is a critical requirement for supporting the food security issue that maintains the function of human society. Many studies have predicted the effects of climate changes on crop production using a combination of filed studies and models, but there has been limited evidence relating decadal-scale climate change to global crop growth and the spatiotemporal distribution of multiple cropping system. Using long-term satellite-derived Normalized Difference Vegetation Index (NDVI and observed climate data from 1982 to 2012, we investigated the crop growth trend, spatiotemporal pattern trend of agricultural cropping intensity, and their potential correlations with respect to the climate change drivers at a global scale. Results show that 82.97 % of global cropland maximum NDVI witnesses an increased trend while 17.03 % of that shows a decreased trend over the past three decades. The spatial distribution of multiple cropping system is observed to expand from lower latitude to higher latitude, and the increased cropping intensity is also witnessed globally. In terms of regional major crop zones, results show that all nine selected zones have an obvious upward trend of crop maximum NDVI (p < 0.001, and as for climatic drivers, the gradual temperature and precipitation changes have had a measurable impact on the crop growth trend.

A Framework for Developing Artificial Intelligence for Autonomous Satellite Operations

Science.gov (United States)

Anderson, Jason L.; Kurfess, Franz J.; Puig-Suari, Jordi

2009-09-01

In the world of educational satellites, student teams manually conduct operations daily. Educational satellites typically travel in a Low Earth Orbit allowing communication for approximately thirty minutes each day. Manual operations during these times is manageable for student teams as the required manpower is minimal. The international Global Educational Network for Satellite Operations (GENSO), however, promises satellite contact upwards of sixteen hours per day by connecting earth stations globally through the Internet. This large increase in satellite communication time makes manual student operations unreasonable and alternatives must be explored. This paper introduces a framework to conduct autonomous satellite operations using different AI methodologies. This paper additionally demonstrates the framework's usability by introducing a sample rule-based implementation for Cal Poly's CubeSat, CP3.

Mobile System for the Measurement of Dose Rates with locations determined by means of satellite positioning technology

International Nuclear Information System (INIS)

Baeza, A.; Rio, L.M. del; Macias, J.A.; Vasco, J.

1998-01-01

Our laboratory has been developing and implementing a Real Time Radiological Warning Network around the Almaraz Nuclear Power Plant since 1990. It consists of six gamma dosimetry stations, two devices for the detection of radio-iodines and alpha, beta, and gamma emissions in air, a monitor for the continuous measurement of gamma radiation in water, and two basic meteorological stations. In this context, we have developed a mobile station endowed with a device for the measurement of dose rates which uses satellite positioning technology (GPS) so that it can be located remotely. The information gathered is sent back to our central laboratory in real/or deferred time through the digital mobile telephone network. A twofold utility is foreseen for this station: (a) action in the case of a radiological alert situation detected by our network, and (b) the performance of radiological-dosimetric studies of distant geographical zones. (Author)

Small Aperture Telescope Observations of Co-located Geostationary Satellites

Science.gov (United States)

Scott, R.; Wallace, B.

As geostationary orbit (GEO) continues to be populated, satellite operators are increasing usage of co-location techniques to maximize usage of fewer GEO longitude slots. Co-location is an orbital formation strategy where two or more geostationary satellites reside within one GEO stationkeeping box. The separation strategy used to prevent collision between the co-located satellites generally uses eccentricity (radial separation) and inclination (latitude separation) vector offsets. This causes the satellites to move in relative motion ellipses about each other as the relative longitude drift between the satellites is near zero. Typical separations between the satellites varies from 1 to 100 kilometers. When co-located satellites are observed by optical ground based space surveillance sensors the participants appear to be separated by a few minutes of arc or less in angular extent. Under certain viewing geometries, these satellites appear to visually conjunct even though the satellites are, in fact, well separated spatially. In situations where one of the co-located satellites is more optically reflective than the other, the reflected sunglint from the more reflective satellite can overwhelm the other. This less frequently encountered issue causes the less reflective satellite to be glint masked in the glare of the other. This paper focuses on space surveillance observations on co-located Canadian satellites using a small optical telescope operated by Defence R&D Canada - Ottawa. The two above mentioned problems (cross tagging and glint masking) are investigated and we quantify the results for Canadian operated geostationary satellites. The performance of two line element sets when making in-frame CCD image correlation between the co-located satellites is also examined. Relative visual magnitudes between the co-located members are also inspected and quantified to determine the susceptibility of automated telescopes to glint masking of co-located satellite members.

5 CFR 530.304 - Establishing or increasing special rates.

Science.gov (United States)

2010-01-01

... involved (including exposure to toxic substances or other occupational hazards); or (4) Any other... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Establishing or increasing special rates. 530.304 Section 530.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE...

Social modernization and the increase in the divorce rate.

Science.gov (United States)

Esser, H

1993-03-01

The author develops a micro-model of marital interactions that is used to analyze factors affecting the divorce rate in modern industrialized societies. The core of the model is the concept of production of marital gain and mutual control of this production. "The increase of divorce rates, then, is explained by a steady decrease of institutional and social embeddedness, which helps to solve this kind of an 'assurance game.' The shape of the individual risk is explained by the typical form of change of the 'production functions' of marriages within the first period of adaptation. The inconsistent results concerning womens' labor market participation in linear regression models are explained as a consequence of the (theoretical and statistical) 'interaction' of decreases in embeddedness and increases in external alternatives for women." Comments are included by Karl-Dieter Opp (pp. 278-82) and Ulrich Witt (pp. 283-5). excerpt

TAK1 modulates satellite stem cell homeostasis and skeletal muscle repair

Science.gov (United States)

Ogura, Yuji; Hindi, Sajedah M.; Sato, Shuichi; Xiong, Guangyan; Akira, Shizuo; Kumar, Ashok

2015-01-01

Satellite cells are resident adult stem cells that are required for regeneration of skeletal muscle. However, signalling mechanisms that regulate satellite cell function are less understood. Here we demonstrate that transforming growth factor-β-activated kinase 1 (TAK1) is important in satellite stem cell homeostasis and function. Inactivation of TAK1 in satellite cells inhibits muscle regeneration in adult mice. TAK1 is essential for satellite cell proliferation and its inactivation causes precocious differentiation. Moreover, TAK1-deficient satellite cells exhibit increased oxidative stress and undergo spontaneous cell death, primarily through necroptosis. TAK1 is required for the activation of NF-κB and JNK in satellite cells. Forced activation of NF-κB improves survival and proliferation of TAK1-deficient satellite cells. Furthermore, TAK1-mediated activation of JNK is essential to prevent oxidative stress and precocious differentiation of satellite cells. Collectively, our study suggests that TAK1 is required for maintaining the pool of satellite stem cells and for regenerative myogenesis. PMID:26648529

Impacts of satellite galaxies on the redshift-space distortions

Energy Technology Data Exchange (ETDEWEB)

Hikage, Chiaki [Kobayashi-Maskawa Institute, Nagoya University, Nagoya 464-8602 (Japan); Yamamoto, Kazuhiro, E-mail: hikage@kmi.nagoya-u.ac.jp, E-mail: kazuhiro@hiroshima-u.ac.jp [Department of Physical Sciences, Hiroshima University, Higashi-hiroshima, Kagamiyama 1-3-1, 739-8526 (Japan)

2013-08-01

We study the impacts of the satellite galaxies on the redshift-space distortions. In our multipole power spectrum analysis of the luminous red galaxies (LRGs) samples of the Sloan digital sky survey (SDSS), we have clearly detected the non-zero signature of the hexadecapole and tetrahexadecapole spectrum, which almost disappears in the power spectrum with the sample of the brightest LRGs only. We thus demonstrate that the satellite LRGs in multiple systems make a significant contribution to the multipole power spectrum though its fraction is small. The behavior can be understood by a simple halo model, in which the one-halo term, describing the Finger of God (FoG) effect from the satellite galaxies, makes the dominant contribution to the higher multipole spectra. We demonstrate that the small-scale information of higher multipole spectrum is useful for calibrating the satellite FoG effect and improves the measurement of the cosmic growth rate dramatically. We further demonstrate that the fiber collision in the galaxy survey influences the one-halo term and the higher multipole spectra, because the number of satellite galaxies in the halo occupation distribution (HOD) is changed. We also discuss about the impact of satellite galaxies on future high-redshift surveys targeting the H-alpha emitters.

Millimeter wave propagation modeling of inhomogeneous rain media for satellite communications systems

Science.gov (United States)

Persinger, R. R.; Stutzman, W. L.

1978-01-01

A theoretical propagation model that represents the scattering properties of an inhomogeneous rain often found on a satellite communications link is presented. The model includes the scattering effects of an arbitrary distribution of particle type (rain or ice), particle shape, particle size, and particle orientation within a given rain cell. An associated rain propagation prediction program predicts attenuation, isolation and phase shift as a function of ground rain rate. A frequency independent synthetic storm algorithm is presented that models nonuniform rain rates present on a satellite link. Antenna effects are included along with a discussion of rain reciprocity. The model is verified using the latest available multiple frequency data from the CTS and COMSTAR satellites. The data covers a wide range of frequencies, elevation angles, and ground site locations.

Concept definition study for recovery of tumbling satellites. Volume 2: Supporting research and technology report

Science.gov (United States)

Cable, D. A.; Derocher, W. L., Jr.; Cathcart, J. A.; Keeley, M. G.; Madayev, L.; Nguyen, T. K.; Preese, J. R.

1986-01-01

A number of areas of research and laboratory experiments were identified which could lead to development of a cost efficient remote, disable satellite recovery system. Estimates were planned of disabled satellite motion. A concept is defined as a Tumbling Satellite Recovery kit which includes a modular system, composed of a number of subsystem mechanisms that can be readily integrated into varying combinations. This would enable the user to quickly configure a tailored remote, disabled satellite recovery kit to meet a broad spectrum of potential scenarios. The capability was determined of U.S. Earth based satellite tracking facilities to adequately determine the orientation and motion rates of disabled satellites.

Does sex speed up evolutionary rate and increase biodiversity?

Directory of Open Access Journals (Sweden)

Carlos J Melián

Full Text Available Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious mutations, and adaptation to heterogeneous environments. Slower rates with sex have been attributed to removal of major genetic rearrangements, the cost of finding a mate, vulnerability to predation, and exposure to sexually transmitted diseases. Whether sex speeds or slows evolution, the connection between reproductive mode, the evolutionary rate, and species diversity remains largely unexplored. Here we present a spatially explicit model of ecological and evolutionary dynamics based on DNA sequence change to study the connection between mutation, speciation, and the resulting biodiversity in sexual and asexual populations. We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity. In this way, sex can reduce diversity relative to asexual populations, because it leads to a higher rate of production of new species, but with lower abundances. Our results show that reproductive mode and the mechanisms underlying it can alter the link between mutation, evolutionary rate, speciation and biodiversity and we suggest that a high rate of evolution may not be required to yield high biodiversity.

Effect of Ionosphere on Geostationary Communication Satellite Signals

Science.gov (United States)

Erdem, Esra; Arikan, Feza; Gulgonul, Senol

2016-07-01

Geostationary orbit (GEO) communications satellites allow radio, television, and telephone transmissions to be sent live anywhere in the world. They are extremely important in daily life and also for military applications. Since, satellite communication is an expensive technology addressing crowd of people, it is critical to improve the performance of this technology. GEO satellites are at 35,786 kilometres from Earth's surface situated directly over the equator. A satellite in a geostationary orbit (GEO) appears to stand still in the sky, in a fixed position with respect to an observer on the earth, because the satellite's orbital period is the same as the rotation rate of the Earth. The advantage of this orbit is that ground antennas can be fixed to point towards to satellite without their having to track the satellite's motion. Radio frequency ranges used in satellite communications are C, X, Ku, Ka and even EHG and V-band. Satellite signals are disturbed by atmospheric effects on the path between the satellite and the receiver antenna. These effects are mostly rain, cloud and gaseous attenuation. It is expected that ionosphere has a minor effect on the satellite signals when the ionosphere is quiet. But there are anomalies and perturbations on the structure of ionosphere with respect to geomagnetic field and solar activity and these conditions may cause further affects on the satellite signals. In this study IONOLAB-RAY algorithm is adopted to examine the effect of ionosphere on satellite signals. IONOLAB-RAY is developed to calculate propagation path and characteristics of high frequency signals. The algorithm does not have any frequency limitation and models the plasmasphere up to 20,200 km altitude, so that propagation between a GEO satellite and antenna on Earth can be simulated. The algorithm models inhomogeneous, anisotropic and time dependent structure of the ionosphere with a 3-D spherical grid geometry and calculates physical parameters of the

Satellite myths

Science.gov (United States)

Easton, Roger L.; Hall, David

2008-01-01

Richard Corfield's article “Sputnik's legacy” (October 2007 pp23-27) states that the satellite on board the US Vanguard rocket, which exploded during launch on 6 December 1957 two months after Sputnik's successful take-off, was “a hastily put together contraption of wires and circuitry designed only to send a radio signal back to Earth”. In fact, the Vanguard satellite was developed over a period of several years and put together carefully using the best techniques and equipment available at the time - such as transistors from Bell Laboratories/Western Electric. The satellite contained not one but two transmitters, in which the crystal-controlled oscillators had been designed to measure both the temperature of the satellite shell and of the internal package.

The reionization of galactic satellite populations

Energy Technology Data Exchange (ETDEWEB)

Ocvirk, P.; Gillet, N.; Aubert, D.; Chardin, J. [Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS UMR 7550, 11 rue de l' Université, F-67000 Strasbourg (France); Knebe, A.; Yepes, G. [Grupo de Astrofísica, Departamento de Fisica Teorica, Modulo C-8, Universidad Autónoma de Madrid, Cantoblanco E-280049 (Spain); Libeskind, N.; Gottlöber, S. [Leibniz-Institute für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Hoffman, Y. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

2014-10-10

We use high-resolution simulations of the formation of the local group, post-processed by a radiative transfer code for UV photons, to investigate the reionization of the satellite populations of an isolated Milky Way-M31 galaxy pair in a variety of scenarios. We use an improved version of ATON which includes a simple recipe for radiative feedback. In our baseline models, reionization is initiated by low-mass, radiatively regulated halos at high redshift, until more massive halos appear, which then dominate and complete the reionization process. We investigate the relation between reionization history and present-day positions of the satellite population. We find that the average reionization redshift (z {sub r}) of satellites is higher near galaxy centers (MW and M31). This is due to the inside out reionization patterns imprinted by massive halos within the progenitor during the epoch of reionization, which end up forming the center of the galaxy. Due to incomplete dynamical mixing during galaxy assembly, these early patterns survive to present day, resulting in a clear radial gradient in the average satellite reionization redshift, up to the virial radius of MW and M31 and beyond. In the lowest emissivity scenario, the outer satellites are reionized about 180 Myr later than the inner satellites. This delay decreases with increasing source model emissivity, or in the case of external reionization by Virgo or M31, because reionization occurs faster overall and becomes spatially quasi-uniform at the highest emissivity.

The reionization of galactic satellite populations

International Nuclear Information System (INIS)

Ocvirk, P.; Gillet, N.; Aubert, D.; Chardin, J.; Knebe, A.; Yepes, G.; Libeskind, N.; Gottlöber, S.; Hoffman, Y.

2014-01-01

We use high-resolution simulations of the formation of the local group, post-processed by a radiative transfer code for UV photons, to investigate the reionization of the satellite populations of an isolated Milky Way-M31 galaxy pair in a variety of scenarios. We use an improved version of ATON which includes a simple recipe for radiative feedback. In our baseline models, reionization is initiated by low-mass, radiatively regulated halos at high redshift, until more massive halos appear, which then dominate and complete the reionization process. We investigate the relation between reionization history and present-day positions of the satellite population. We find that the average reionization redshift (z r ) of satellites is higher near galaxy centers (MW and M31). This is due to the inside out reionization patterns imprinted by massive halos within the progenitor during the epoch of reionization, which end up forming the center of the galaxy. Due to incomplete dynamical mixing during galaxy assembly, these early patterns survive to present day, resulting in a clear radial gradient in the average satellite reionization redshift, up to the virial radius of MW and M31 and beyond. In the lowest emissivity scenario, the outer satellites are reionized about 180 Myr later than the inner satellites. This delay decreases with increasing source model emissivity, or in the case of external reionization by Virgo or M31, because reionization occurs faster overall and becomes spatially quasi-uniform at the highest emissivity.

Satellite remote sensing in epidemiological studies.

Science.gov (United States)

Sorek-Hamer, Meytar; Just, Allan C; Kloog, Itai

2016-04-01

Particulate matter air pollution is a ubiquitous exposure linked with multiple adverse health outcomes for children and across the life course. The recent development of satellite-based remote-sensing models for air pollution enables the quantification of these risks and addresses many limitations of previous air pollution research strategies. We review the recent literature on the applications of satellite remote sensing in air quality research, with a focus on their use in epidemiological studies. Aerosol optical depth (AOD) is a focus of this review and a significant number of studies show that ground-level particulate matter can be estimated from columnar AOD. Satellite measurements have been found to be an important source of data for particulate matter model-based exposure estimates, and recently have been used in health studies to increase the spatial breadth and temporal resolution of these estimates. It is suggested that satellite-based models improve our understanding of the spatial characteristics of air quality. Although the adoption of satellite-based measures of air quality in health studies is in its infancy, it is rapidly growing. Nevertheless, further investigation is still needed in order to have a better understanding of the AOD contribution to these prediction models in order to use them with higher accuracy in epidemiological studies.

Akt1 deficiency diminishes skeletal muscle hypertrophy by reducing satellite cell proliferation.

Science.gov (United States)

Moriya, Nobuki; Miyazaki, Mitsunori

2018-02-14

Skeletal muscle mass is determined by the net dynamic balance between protein synthesis and degradation. Although the Akt/mechanistic target of rapamycin (mTOR)-dependent pathway plays an important role in promoting protein synthesis and subsequent skeletal muscle hypertrophy, the precise molecular regulation of mTOR activity by the upstream protein kinase Akt is largely unknown. In addition, the activation of satellite cells has been indicated as a key regulator of muscle mass. However, the requirement of satellite cells for load-induced skeletal muscle hypertrophy is still under intense debate. In this study, female germline Akt1 knockout (KO) mice were used to examine whether Akt1 deficiency attenuates load-induced skeletal muscle hypertrophy through suppressing mTOR-dependent signaling and satellite cell proliferation. Akt1 KO mice showed a blunted hypertrophic response of skeletal muscle, with a diminished rate of satellite cell proliferation following mechanical overload. In contrast, Akt1 deficiency did not affect the load-induced activation of mTOR signaling and the subsequent enhanced rate of protein synthesis in skeletal muscle. These observations suggest that the load-induced activation of mTOR signaling occurs independently of Akt1 regulation and that Akt1 plays a critical role in regulating satellite cell proliferation during load-induced muscle hypertrophy.

The YORP effect on the GOES 8 and GOES 10 satellites: A case study

Science.gov (United States)

Albuja, Antonella A.; Scheeres, Daniel J.; Cognion, Rita L.; Ryan, William; Ryan, Eileen V.

2018-01-01

The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is a proposed explanation for the observed rotation behavior of inactive satellites in Earth orbit. This paper further explores the YORP effect for highly asymmetric inactive satellites. Satellite models are developed to represent the GOES 8 and GOES 10 satellites, both of which are currently inactive in geosynchronous Earth orbit (GEO). A simple satellite model for the GOES 8 satellite is used to analyze the short period variations of the angular velocity and obliquity as a result of the YORP effect. A more complex model for the rotational dynamics of the GOES 8 and GOES 10 satellites are developed to probe their sensitivity and to match observed spin periods and states of these satellites. The simulated rotation periods are compared to observations for both satellites. The comparison between YORP theory and observed rotation rates for both satellites show that the YORP effect could be the cause for the observed rotational behavior. The YORP model also predicts a novel state for the GOES 8 satellite, namely that it could periodically fall into a tumbling rotation state. Recent observations of this satellite are consistent with this prediction.

Reconstructing Global-scale Ionospheric Outflow With a Satellite Constellation

Science.gov (United States)

Liemohn, M. W.; Welling, D. T.; Jahn, J. M.; Valek, P. W.; Elliott, H. A.; Ilie, R.; Khazanov, G. V.; Glocer, A.; Ganushkina, N. Y.; Zou, S.

2017-12-01

The question of how many satellites it would take to accurately map the spatial distribution of ionospheric outflow is addressed in this study. Given an outflow spatial map, this image is then reconstructed from a limited number virtual satellite pass extractions from the original values. An assessment is conducted of the goodness of fit as a function of number of satellites in the reconstruction, placement of the satellite trajectories relative to the polar cap and auroral oval, season and universal time (i.e., dipole tilt relative to the Sun), geomagnetic activity level, and interpolation technique. It is found that the accuracy of the reconstructions increases sharply from one to a few satellites, but then improves only marginally with additional spacecraft beyond 4. Increased dwell time of the satellite trajectories in the auroral zone improves the reconstruction, therefore a high-but-not-exactly-polar orbit is most effective for this task. Local time coverage is also an important factor, shifting the auroral zone to different locations relative to the virtual satellite orbit paths. The expansion and contraction of the polar cap and auroral zone with geomagnetic activity influences the coverage of the key outflow regions, with different optimal orbit configurations for each level of activity. Finally, it is found that reconstructing each magnetic latitude band individually produces a better fit to the original image than 2-D image reconstruction method (e.g., triangulation). A high-latitude, high-altitude constellation mission concept is presented that achieves acceptably accurate outflow reconstructions.

Who launched what, when and why; trends in global land-cover observation capacity from civilian earth observation satellites

Science.gov (United States)

Belward, Alan S.; Skøien, Jon O.

2015-05-01

This paper presents a compendium of satellites under civilian and/or commercial control with the potential to gather global land-cover observations. From this we show that a growing number of sovereign states are acquiring capacity for space based land-cover observations and show how geopolitical patterns of ownership are changing. We discuss how the number of satellites flying at any time has progressed as a function of increased launch rates and mission longevity, and how the spatial resolutions of the data they collect has evolved. The first such satellite was launched by the USA in 1972. Since then government and/or private entities in 33 other sovereign states and geopolitical groups have chosen to finance such missions and 197 individual satellites with a global land-cover observing capacity have been successfully launched. Of these 98 were still operating at the end of 2013. Since the 1970s the number of such missions failing within 3 years of launch has dropped from around 60% to less than 20%, the average operational life of a mission has almost tripled, increasing from 3.3 years in the 1970s to 8.6 years (and still lengthening), the average number of satellites launched per-year/per-decade has increased from 2 to 12 and spatial resolution increased from around 80 m to less than 1 m multispectral and less than half a meter for panchromatic; synthetic aperture radar resolution has also fallen, from 25 m in the 1970s to 1 m post 2007. More people in more countries have access to data from global land-cover observing spaceborne missions at a greater range of spatial resolutions than ever before. We provide a compendium of such missions, analyze the changes and shows how innovation, the need for secure data-supply, national pride, falling costs and technological advances may underpin the trends we document.

Effects of voluntary wheel running on satellite cells in the rat plantaris muscle.

Science.gov (United States)

Kurosaka, Mitsutoshi; Naito, Hisashi; Ogura, Yuji; Kojima, Atsushi; Goto, Katsumasa; Katamoto, Shizuo

2009-01-01

This study investigated the effects of voluntary wheel running on satellite cells in the rat plantaris muscle. Seventeen 5-week-old male Wistar rats were assigned to a control (n = 5) or training (n = 12) group. Each rat in the training group ran voluntarily in a running-wheel cage for 8 weeks. After the training period, the animals were anesthetized, and the plantaris muscles were removed, weighed, and analyzed immunohistochemically and biochemically. Although there were no significant differences in muscle weight or fiber area between the groups, the numbers of satellite cells and myonuclei per muscle fiber, percentage of satellite cells, and citrate synthase activity were significantly higher in the training group compared with the control group (p run in the training group (r = 0.61, p running can induce an increase in the number of satellite cells without changing the mean fiber area in the rat plantaris muscle; this increase in satellite cell content is a function of distance run. Key pointsThere is no study about the effect of voluntary running on satellite cells in the rat plantaris muscle.Voluntary running training causes an increase of citrate synthase activity in the rat plantaris muscle but does not affect muscle weight and mean fiber area in the rat plantaris muscle.Voluntary running can induce an increase in the number of satellite cells without hypertrophy of the rat plantaris muscle.

Binding proteins enhance specific uptake rate by increasing the substrate-transporter encounter rate.

Science.gov (United States)

Bosdriesz, Evert; Magnúsdóttir, Stefanía; Bruggeman, Frank J; Teusink, Bas; Molenaar, Douwe

2015-06-01

Microorganisms rely on binding-protein assisted, active transport systems to scavenge for scarce nutrients. Several advantages of using binding proteins in such uptake systems have been proposed. However, a systematic, rigorous and quantitative analysis of the function of binding proteins is lacking. By combining knowledge of selection pressure and physiochemical constraints, we derive kinetic, thermodynamic, and stoichiometric properties of binding-protein dependent transport systems that enable a maximal import activity per amount of transporter. Under the hypothesis that this maximal specific activity of the transport complex is the selection objective, binding protein concentrations should exceed the concentration of both the scarce nutrient and the transporter. This increases the encounter rate of transporter with loaded binding protein at low substrate concentrations, thereby enhancing the affinity and specific uptake rate. These predictions are experimentally testable, and a number of observations confirm them. © 2015 FEBS.

Relative tracking control of constellation satellites considering inter-satellite link

Science.gov (United States)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

Mobile satellite service communications tests using a NASA satellite

Science.gov (United States)

Chambers, Katherine H.; Koschmeder, Louis A.; Hollansworth, James E.; ONeill, Jack; Jones, Robert E.; Gibbons, Richard C.

1995-01-01

Emerging applications of commercial mobile satellite communications include satellite delivery of compact disc (CD) quality radio to car drivers who can select their favorite programming as they drive any distance; transmission of current air traffic data to aircraft; and handheld communication of data and images from any remote corner of the world. Experiments with the enabling technologies and tests and demonstrations of these concepts are being conducted before the first satellite is launched by utilizing an existing NASA spacecraft.

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....... 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...... 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....

A study on increasing the breeding rate of chicks with low-dosage stimulation

International Nuclear Information System (INIS)

Wang Shuyu; Zhang Hongwei; Cui Zaijiu; Liu Dashen; Zhang Peng; Yi Jun

1991-10-01

During the years 1985 ∼ 1990, the semen of male fowl was irradiated by β-rays, the survival time of the spermatozoa was prolonged and fertility increased by 2% to 5%. The breeding eggs of 'Harbin White hen' were irradiated by 60 Co γ-rays to stimulate the growth of the blastoderm of fertilized eggs, the hatching rate increased by 6.86%, the healthy bird rate increased by 5.52%, and the chick weight increased by 5% to 6%. The egg production rate of the first irradiated generation hens increased by 8.03%, the first-egg age of the second irradiated generation hens shifted 6 to 7 weeks earlier and the egg production period prolonged. 72-week egg production was raised by 10.48%

Flare observation by the satellite 'Hinotori'

International Nuclear Information System (INIS)

Tanaka, Toshio

1981-01-01

The satellite ''Hinotori'' makes 5 rounds a day and is doing flare observation. The total observation days amounted to 94 days. Among the observed flares, the quiet mode flares were picked up from the reproduced data. The plot of the time variation of flares was obtained for four energy bands, HXM-1 (17 to 40 keV), HXM2 - 7 (over 40 keV), FLM-L (1 to 5 keV) and FLM-H (5 to 12 keV). At present, the judge of flares is made by using hard X-ray of the HXM-1 plot. False signals were completely removed. A large percentage of big flares was collected by Hinotori, eleven X-class flares were recorded. The operation status of ''Hinotori'' has been in good condition. The spin frequency has increased with a constant rate. (Kato, T.)

Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

Coverage Extension via Side-Lobe Transmission in Multibeam Satellite System

OpenAIRE

Gharanjik, Ahmad; Kmieciak, Jarek; Shankar, Bhavani; Ottersten, Björn

2017-01-01

In this paper, we study feasibility of coverage extension of a multibeam satellite network by providing low-rate communications to terminals located outside the coverage of main beams. Focusing on the MEO satellite network, and using realistic link budgets from O3b networks, we investigate the performance of both forward and return-links for terminals stationed in the side lobes of the main beams. Particularly, multi-carrier transmission for forward-link and single carrier transmission for re...

Assimilation of satellite data to increase the reliability of the wave predictions in the Black Sea

Science.gov (United States)

Rusu, Liliana; Raileanu, Alina

2015-04-01

In order to improve the wave predictions provided in the Black Sea by a wave modelling system based on the SWAN (Simulating Waves Nearshore) spectral model, a technique for assimilating the satellite data has been implemented and evaluated. For this purpose, an approach based on the Optimal Interpolation method has been considered and its results are discussed in the present work. As a first step, SWAN model simulations have been carried out for a 5-year interval (2004-2008). The assimilation is made in terms of the significant wave height (Hs) for each 24 hours considering data coming from 4 satellites (ERS-2, JASON-1, JASON-2, GEOSAT Follow-On). Subsequently, data provided by two other satellites (ENVISAT and TOPEX) are used for validations. To assess the improvement brought in the model predictions by the assimilation scheme, a comparison has been performed between the model results with and without assimilation. The statistical parameters evaluated are: bias, mean absolute error, RMS error, scatter index, correlation coefficient and symmetric slope. The results show that the data assimilation procedure induces a significant improvement of the statistical parameters (lower values for bias, errors and scatter index and values closer to the unity of the correlation coefficient and for the symmetric slope). It was found also that an important factor in improving the wave predictions is represented by the value of the correlation length accounted for the Hs prediction errors (Lmax). Previous studies indicate for this length a value around four degrees in the vicinity of 45 degrees latitude (which corresponds also to the basin of the Black Sea). This value was first considered in the assimilation technique. On the other hand, taking also into account the fact that in the Black Sea the wind-sea waves are dominant, lower values for the parameter Lmax were tested as well and it seems that the most appropriate value for this parameter is between three and four degrees

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.

Satellite image collection optimization

Science.gov (United States)

Martin, William

2002-09-01

Imaging satellite systems represent a high capital cost. Optimizing the collection of images is critical for both satisfying customer orders and building a sustainable satellite operations business. We describe the functions of an operational, multivariable, time dynamic optimization system that maximizes the daily collection of satellite images. A graphical user interface allows the operator to quickly see the results of what if adjustments to an image collection plan. Used for both long range planning and daily collection scheduling of Space Imaging's IKONOS satellite, the satellite control and tasking (SCT) software allows collection commands to be altered up to 10 min before upload to the satellite.

Estimating Next Primary Productivity using Satellite and Ancillary Data

Science.gov (United States)

Choudhury, B. J.

The net primary productivity (C) or annual rate of carbon accumulation per unit ground area by terrestrial plant communities is the difference of the rate of gross photosynthesis (Ag) and autotrophic respiration (R) per unit ground area. Although available observations show that R is a large and variable fraction of Ag, viz., 0.3 to 0.7, it is generally recognized that much uncertainties exist in this fraction due to difficulties associated with the needed measurements. Additional uncertainties arise when these measurements are extrapolated to regional or global land surface using empirical equations, for example, using regression equations relating C to mean annual precipitation and air temperature. Here, a process- based approach has been taken to calculate Ag and R using satellite and ancillary data. Ag has been expressed as a product of radiation use efficiency, magnitude of intercepted photosynthetically active radiation (PAR), and normalized by stresses due to soil water shortage and air temperature away from the optimum range. A biophysical model has been used to determine the radiation use efficiency from the maximum rate of carbon assimilation by a leaf, foliage temperature, and the fraction of diffuse PAR incident on a canopy. All meteorological data (PAR, air temperature, precipitation, etc.) needed for the calculation are derived from satellite observations, while a land use, land cover data (based on satellite and ground measurements) have been used to assess the maximum rate of carbon assimilation by a leaf of varied cover type based on field measurements. R has been calculated as the sum of maintenance and growth components. The maintenance respiration of foliage and live fine roots at a standard temperature of different land cover has been determined from their nitrogen content using field and satellite measurements, while that of living fraction of woody stem (viz., sapwood) from the seasonal maximum leaf area index as determined from satellite

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

Widespread increase of tree mortality rates in the western United States

Science.gov (United States)

Phillip J. van Mantgem; Nathan L. Stephenson; John C. Byrne; Lori D. Daniels; Jerry F. Franklin; Peter Z. Fule; Mark E. Harmon; Andrew J. Larson; Jeremy M. Smith; Alan H. Taylor; Thomas T. Veblen

2009-01-01

Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29...

Increased rates of cesarean sections and large families: a potentially dangerous combination.

Science.gov (United States)

Saleh, Ahmed M; Dudenhausen, Joachim W; Ahmed, Badreldeen

2017-07-26

Rates of cesarean sections have been on the rise over the past three decades all over the world, despite the ideal rate of 10-15% that had been set by the World Health Organization (WHO) in 1985, in Fortaleza, Brazil. This epidemic increase in the rate of cesarean delivery is due to many factors which include, cesarean delivery on request, advanced maternal age at first pregnancy, decrease in number of patients who are willing to try vaginal birth after cesarean delivery, virtual disappearance of vaginal breech delivery, perceived increase in the weight of the fetus and increase in the number of women with chronic medical conditions such as Diabetes Mellitus and congenital heart disease in the reproductive age. There is no doubt that cesarean delivery is a safe procedure and it is getting safer and safer for many reasons. However, like all other surgical procedures it is not without risks both to the mother and the new born. There is a substantial increase in the incidence of morbidly adherent placenta and the risk of scar pregnancy. In the Middle East and many African and Asian countries women tend to have large families. The number of previous cesarean section deliveries is directly proportional to the risk of developing morbidly adherent placenta. Morbidly adherent placenta is the most common cause of emergency postpartum hysterectomy, which is often associated with multiple surgical complications, severe maternal morbidity and mortality. The increased rates of cesarean sections lead to increased rates of scar pregnancies, which can have lethal consequences. Cesarean delivery has a negative impact on the infant immune system. This effect on the infant led to the introduction of a new concept called "Vaginal seeding". This refers to the practice of transferring some maternal vaginal fluid to the infant born via cesarean section in an effort to enhance its immune system.

Sox2 promotes survival of satellite glial cells in vitro

International Nuclear Information System (INIS)

Koike, Taro; Wakabayashi, Taketoshi; Mori, Tetsuji; Hirahara, Yukie; Yamada, Hisao

2015-01-01

Sox2 is a transcriptional factor expressed in neural stem cells. It is known that Sox2 regulates cell differentiation, proliferation and survival of the neural stem cells. Our previous study showed that Sox2 is expressed in all satellite glial cells of the adult rat dorsal root ganglion. In this study, to examine the role of Sox2 in satellite glial cells, we establish a satellite glial cell-enriched culture system. Our culture method succeeded in harvesting satellite glial cells with the somata of neurons in the dorsal root ganglion. Using this culture system, Sox2 was downregulated by siRNA against Sox2. The knockdown of Sox2 downregulated ErbB2 and ErbB3 mRNA at 2 and 4 days after siRNA treatment. MAPK phosphorylation, downstream of ErbB, was also inhibited by Sox2 knockdown. Because ErbB2 and ErbB3 are receptors that support the survival of glial cells in the peripheral nervous system, apoptotic cells were also counted. TUNEL-positive cells increased at 5 days after siRNA treatment. These results suggest that Sox2 promotes satellite glial cell survival through the MAPK pathway via ErbB receptors. - Highlights: • We established satellite glial cell culture system. • Function of Sox2 in satellite glial cell was examined using siRNA. • Sox2 knockdown downregulated expression level of ErbB2 and ErbB3 mRNA. • Sox2 knockdown increased apoptotic satellite glial cell. • Sox2 promotes satellite glial cell survival through ErbB signaling

Sox2 promotes survival of satellite glial cells in vitro

Energy Technology Data Exchange (ETDEWEB)

Koike, Taro, E-mail: koiket@hirakata.kmu.ac.jp; Wakabayashi, Taketoshi; Mori, Tetsuji; Hirahara, Yukie; Yamada, Hisao

2015-08-14

Sox2 is a transcriptional factor expressed in neural stem cells. It is known that Sox2 regulates cell differentiation, proliferation and survival of the neural stem cells. Our previous study showed that Sox2 is expressed in all satellite glial cells of the adult rat dorsal root ganglion. In this study, to examine the role of Sox2 in satellite glial cells, we establish a satellite glial cell-enriched culture system. Our culture method succeeded in harvesting satellite glial cells with the somata of neurons in the dorsal root ganglion. Using this culture system, Sox2 was downregulated by siRNA against Sox2. The knockdown of Sox2 downregulated ErbB2 and ErbB3 mRNA at 2 and 4 days after siRNA treatment. MAPK phosphorylation, downstream of ErbB, was also inhibited by Sox2 knockdown. Because ErbB2 and ErbB3 are receptors that support the survival of glial cells in the peripheral nervous system, apoptotic cells were also counted. TUNEL-positive cells increased at 5 days after siRNA treatment. These results suggest that Sox2 promotes satellite glial cell survival through the MAPK pathway via ErbB receptors. - Highlights: • We established satellite glial cell culture system. • Function of Sox2 in satellite glial cell was examined using siRNA. • Sox2 knockdown downregulated expression level of ErbB2 and ErbB3 mRNA. • Sox2 knockdown increased apoptotic satellite glial cell. • Sox2 promotes satellite glial cell survival through ErbB signaling.

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

Increasing low birth weight rates: deliveries in a tertiary hospital in istanbul.

Science.gov (United States)

Akin, Yasemin; Cömert, Serdar; Turan, Cem; Unal, Orhan; Piçak, Abdülkadir; Ger, Lale; Telatar, Berrin

2010-09-01

Prevalence of low birth weight deliveries may vary across different environments. The necessity of determination of regional data prompted this study. Information of all deliveries from January 2004 to December 2008 was obtained from delivery registry records retrospectively. Initial data including birth weight, vital status, sex, maternal age and mode of delivery were recorded using medical files. The frequency of low birth weight, very low birth weight, extremely low birth weight and stillbirth deliveries were determined. Among 19,533 total births, there were 450 (23.04 per 1000) stillbirths. Low birth weight rate was 10.61%. A significant increase in yearly distribution of low birth weight deliveries was observed (Pbirth weight and extremely low birth weight delivery rates were 3.14% and 1.58% respectively. Among 2073 low birth weight infants, 333 (16.06%) were stillbirths. The stillbirth delivery rate and the birth of a female infant among low birth weight deliveries were significantly higher than infants with birth weight ≥2500g (Pbirth weight and maternal age. The rate of cesarean section among low birth weight infants was 49.4%. High low birth weight and stillbirth rates, as well as the increase in low birth weight deliveries over the past five years in this study are striking. For reduction of increased low birth weight rates, appropriate intervention methods should be initiated.

GALAXIES IN FILAMENTS HAVE MORE SATELLITES: THE INFLUENCE OF THE COSMIC WEB ON THE SATELLITE LUMINOSITY FUNCTION IN THE SDSS

International Nuclear Information System (INIS)

Guo, Quan; Libeskind, N. I.; Tempel, E.

2015-01-01

We investigate whether the satellite luminosity function (LF) of primary galaxies identified in the Sloan Digital Sky Survey (SDSS) depends on whether the host galaxy is in a filament or not. Isolated primary galaxies are identified in the SDSS spectroscopic sample, and potential satellites (that are up to four magnitudes fainter than their hosts) are searched for in the much deeper photometric sample. Filaments are constructed from the galaxy distribution by the Bisous process. Isolated primary galaxies are divided into two subsamples: those in filaments and those not in filaments. We examine the stacked mean satellite LF of both the filament and nonfilament samples and find that, on average, the satellite LF of galaxies in filaments is significantly higher than those of galaxies not in filaments. The filamentary environment can increase the abundance of the brightest satellites (M sat. < M prim. + 2.0) by a factor of ∼2 compared with nonfilament isolated galaxies. This result is independent of the primary galaxy magnitude, although the satellite LF of galaxies in the faintest magnitude bin is too noisy to determine if such a dependence exists. Because our filaments are extracted from a spectroscopic flux-limited sample, we consider the possibility that the difference in satellite LF is due to a redshift, color, or environmental bias, finding these to be insufficient to explain our result. The dependence of the satellite LF on the cosmic web suggests that the filamentary environment may have a strong effect on the efficiency of galaxy formation

GALAXIES IN FILAMENTS HAVE MORE SATELLITES: THE INFLUENCE OF THE COSMIC WEB ON THE SATELLITE LUMINOSITY FUNCTION IN THE SDSS

Energy Technology Data Exchange (ETDEWEB)

Guo, Quan; Libeskind, N. I. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Tempel, E., E-mail: qguo@aip.de [Tartu Observatory, Observatooriumi 1, 61602 Tõravere (Estonia)

2015-02-20

We investigate whether the satellite luminosity function (LF) of primary galaxies identified in the Sloan Digital Sky Survey (SDSS) depends on whether the host galaxy is in a filament or not. Isolated primary galaxies are identified in the SDSS spectroscopic sample, and potential satellites (that are up to four magnitudes fainter than their hosts) are searched for in the much deeper photometric sample. Filaments are constructed from the galaxy distribution by the Bisous process. Isolated primary galaxies are divided into two subsamples: those in filaments and those not in filaments. We examine the stacked mean satellite LF of both the filament and nonfilament samples and find that, on average, the satellite LF of galaxies in filaments is significantly higher than those of galaxies not in filaments. The filamentary environment can increase the abundance of the brightest satellites (M {sub sat.} < M {sub prim.} + 2.0) by a factor of ∼2 compared with nonfilament isolated galaxies. This result is independent of the primary galaxy magnitude, although the satellite LF of galaxies in the faintest magnitude bin is too noisy to determine if such a dependence exists. Because our filaments are extracted from a spectroscopic flux-limited sample, we consider the possibility that the difference in satellite LF is due to a redshift, color, or environmental bias, finding these to be insufficient to explain our result. The dependence of the satellite LF on the cosmic web suggests that the filamentary environment may have a strong effect on the efficiency of galaxy formation.

General Purpose Graphics Processing Unit Based High-Rate Rice Decompression and Reed-Solomon Decoding

Energy Technology Data Exchange (ETDEWEB)

Loughry, Thomas A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-02-01

As the volume of data acquired by space-based sensors increases, mission data compression/decompression and forward error correction code processing performance must likewise scale. This competency development effort was explored using the General Purpose Graphics Processing Unit (GPGPU) to accomplish high-rate Rice Decompression and high-rate Reed-Solomon (RS) decoding at the satellite mission ground station. Each algorithm was implemented and benchmarked on a single GPGPU. Distributed processing across one to four GPGPUs was also investigated. The results show that the GPGPU has considerable potential for performing satellite communication Data Signal Processing, with three times or better performance improvements and up to ten times reduction in cost over custom hardware, at least in the case of Rice Decompression and Reed-Solomon Decoding.

Classification of Clouds in Satellite Imagery Using Adaptive Fuzzy Sparse Representation

Directory of Open Access Journals (Sweden)

Wei Jin

2016-12-01

Full Text Available Automatic cloud detection and classification using satellite cloud imagery have various meteorological applications such as weather forecasting and climate monitoring. Cloud pattern analysis is one of the research hotspots recently. Since satellites sense the clouds remotely from space, and different cloud types often overlap and convert into each other, there must be some fuzziness and uncertainty in satellite cloud imagery. Satellite observation is susceptible to noises, while traditional cloud classification methods are sensitive to noises and outliers; it is hard for traditional cloud classification methods to achieve reliable results. To deal with these problems, a satellite cloud classification method using adaptive fuzzy sparse representation-based classification (AFSRC is proposed. Firstly, by defining adaptive parameters related to attenuation rate and critical membership, an improved fuzzy membership is introduced to accommodate the fuzziness and uncertainty of satellite cloud imagery; secondly, by effective combination of the improved fuzzy membership function and sparse representation-based classification (SRC, atoms in training dictionary are optimized; finally, an adaptive fuzzy sparse representation classifier for cloud classification is proposed. Experiment results on FY-2G satellite cloud image show that, the proposed method not only improves the accuracy of cloud classification, but also has strong stability and adaptability with high computational efficiency.

Classification of Clouds in Satellite Imagery Using Adaptive Fuzzy Sparse Representation

Science.gov (United States)

Jin, Wei; Gong, Fei; Zeng, Xingbin; Fu, Randi

2016-01-01

Automatic cloud detection and classification using satellite cloud imagery have various meteorological applications such as weather forecasting and climate monitoring. Cloud pattern analysis is one of the research hotspots recently. Since satellites sense the clouds remotely from space, and different cloud types often overlap and convert into each other, there must be some fuzziness and uncertainty in satellite cloud imagery. Satellite observation is susceptible to noises, while traditional cloud classification methods are sensitive to noises and outliers; it is hard for traditional cloud classification methods to achieve reliable results. To deal with these problems, a satellite cloud classification method using adaptive fuzzy sparse representation-based classification (AFSRC) is proposed. Firstly, by defining adaptive parameters related to attenuation rate and critical membership, an improved fuzzy membership is introduced to accommodate the fuzziness and uncertainty of satellite cloud imagery; secondly, by effective combination of the improved fuzzy membership function and sparse representation-based classification (SRC), atoms in training dictionary are optimized; finally, an adaptive fuzzy sparse representation classifier for cloud classification is proposed. Experiment results on FY-2G satellite cloud image show that, the proposed method not only improves the accuracy of cloud classification, but also has strong stability and adaptability with high computational efficiency. PMID:27999261

The coffee diterpene cafestol increases plasma triacylglycerol by increasing the production rate of large VLDL apolipoprotein B in healthy normolipidemic subjects

NARCIS (Netherlands)

Roos, de B.; Caslake, M.J.; Stalenhoef, A.F.H.; Bedford, D.; Demacker, P.N.; Katan, M.B.; Packard, C.J.

2001-01-01

Background: Cafestol is a diterpene in unfiltered coffee that raises plasma triacylglycerol in humans. Objective: We studied whether cafestol increases plasma triacylglycerol by increasing the production rate or by decreasing the fractional catabolic rate of VLDL1 [Svedberg flotation unit (Sf)

Power Processing Unit For Micro Satellite Electric Propulsion System

Directory of Open Access Journals (Sweden)

Savvas Spiridon

2017-01-01

Full Text Available The Micro Satellite Electric Propulsion System (MEPS program has been originated by the increasing need to provide a low-cost and low-power Electric Propulsion System (EPS for small satellites ( 92%, small size and weight and high reliability. Its functional modules and preliminary results obtained at breadboard level are also presented.

Satellite Communications

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Satellite Communications. Arthur C Clarke wrote a seminal paper in 1945 in wireless world. Use three satellites in geo-synchronous orbit to enable intercontinental communications. System could be realised in '50 to 100 years'

The SUMO Ship Detector Algorithm for Satellite Radar Images

Directory of Open Access Journals (Sweden)

Harm Greidanus

2017-03-01

Full Text Available Search for Unidentified Maritime Objects (SUMO is an algorithm for ship detection in satellite Synthetic Aperture Radar (SAR images. It has been developed over the course of more than 15 years, using a large amount of SAR images from almost all available SAR satellites operating in L-, C- and X-band. As validated by benchmark tests, it performs very well on a wide range of SAR image modes (from Spotlight to ScanSAR and resolutions (from 1–100 m and for all types and sizes of ships, within the physical limits imposed by the radar imaging. This paper describes, in detail, the algorithmic approach in all of the steps of the ship detection: land masking, clutter estimation, detection thresholding, target clustering, ship attribute estimation and false alarm suppression. SUMO is a pixel-based CFAR (Constant False Alarm Rate detector for multi-look radar images. It assumes a K distribution for the sea clutter, corrected however for deviations of the actual sea clutter from this distribution, implementing a fast and robust method for the clutter background estimation. The clustering of detected pixels into targets (ships uses several thresholds to deal with the typically irregular distribution of the radar backscatter over a ship. In a multi-polarization image, the different channels are fused. Azimuth ambiguities, a common source of false alarms in ship detection, are removed. A reliability indicator is computed for each target. In post-processing, using the results of a series of images, additional false alarms from recurrent (fixed targets including range ambiguities are also removed. SUMO can run in semi-automatic mode, where an operator can verify each detected target. It can also run in fully automatic mode, where batches of over 10,000 images have successfully been processed in less than two hours. The number of satellite SAR systems keeps increasing, as does their application to maritime surveillance. The open data policy of the EU�

Music increases alcohol consumption rate in young females.

Science.gov (United States)

Stafford, Lorenzo D; Dodd, Hannah

2013-10-01

Previous field research has shown that individuals consumed more alcohol and at a faster rate in environments paired with loud music. Theoretically, this effect has been linked to approach/avoidance accounts of how music influences arousal and mood, but no work has tested this experimentally. In the present study, female participants (n = 45) consumed an alcoholic (4% alcohol-by-volume) beverage in one of three contexts: slow tempo music, fast tempo music, or a no-music control. Results revealed that, compared with the control, the beverage was consumed fastest in the two music conditions. Interestingly, whereas arousal and negative mood declined in the control condition, this was not the case for either of the music conditions, suggesting a downregulation of alcohol effects. We additionally found evidence for music to disrupt sensory systems in that, counterintuitively, faster consumption was driven by increases in perceived alcohol strength, which, in turn, predicted lower breath alcohol level (BrAL). These findings suggest a unique interaction of music environment and psychoactive effects of alcohol itself on consumption rate. Because alcohol consumed at a faster rate induces greater intoxication, these findings have implications for applied and theoretical work. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Satellite spectrophotometer for research of the atmospheric ozone

International Nuclear Information System (INIS)

Getzov, P.; Mardirossian, G.; Stoyanov, S.

2014-01-01

The measurement of atmospheric ozone and its influence upon climate and life on Earth is undoubtedly one of the most pressing issues of present time. A mathematical model of an optical tract of a spectrophotometer has been designed. The paper presents the functional scheme of a satellite optoelectronic spectrophotometer for measuring the total content of atmospheric ozone and other gas components of the atmosphere, which has increased precision, smaller weight and energy consumption, increased space and time resolution, quickness of reaction and increased volume of useful information. The object of the paper is the design of an appliance which ensures research of ozone content in atmosphere from the board of a satellite

Does stoma site specimen extraction increase postoperative ileostomy complication rates?

Science.gov (United States)

Li, Wanglin; Benlice, Cigdem; Stocchi, Luca; Kessler, Hermann; Gorgun, Emre; Costedio, Meagan

2017-09-01

Minimizing incisions has the potential to decrease hernia formation and wound complications following laparoscopic surgery. It is currently unknown if using the stoma site for specimen extraction affects outcomes. This study aims to evaluate the impact of stoma site extraction on postoperative complication rates in laparoscopic colorectal surgery. After IRB approval, a retrospective comparative review of 738 consecutive patients (405 M) who underwent laparoscopic colorectal surgery with ileostomy between January 2008 and December 2014 was performed. Patients who had a minimally invasive surgery that required an ileostomy were included. Patients were classified into two groups: stoma site extraction (SSE) or non-stoma site extraction (NSSE) and compared by body mass index (BMI), age, comorbidities, American Society of Anesthesiologists score, length of stay, estimated blood loss, parastomal complications, and hernia rate. The parastomal hernia rate was 10.1% for the SSE group (n = 14) and 4.2% for the NSSE group (n = 25) (p = 0.007). The need for additional surgeries was 7/139 (5.0%) for the SSE group and 27/599 (4.5%) for the NSSE group (p = 0.79). There was no difference in the hernia rate after stoma closure in either group. There was no difference in single incision laparoscopic surgery versus conventional laparoscopy or robotic-assisted laparoscopy on stoma site complications in patients with SSE. SSE, transfusion, and BMI >30 were found to be independent factors associated with increased stoma site complications. SSE does increase stoma site complications. SSE should be used with caution, or in conjunction with other techniques to reduce hernias in patients requiring a permanent stoma or with an elevated BMI. The increase in stoma site complications does not translate into additional surgeries or postoperative sequelae following stoma reversal and is a reasonable option in patients requiring a temporary stoma.

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...

Human artificial chromosomes with alpha satellite-based de novo centromeres show increased frequency of nondisjunction and anaphase lag.

Science.gov (United States)

Rudd, M Katharine; Mays, Robert W; Schwartz, Stuart; Willard, Huntington F

2003-11-01

Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.

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...

The mass dependence of satellite quenching in Milky Way-like haloes

Science.gov (United States)

Phillips, John I.; Wheeler, Coral; Cooper, Michael C.; Boylan-Kolchin, Michael; Bullock, James S.; Tollerud, Erik

2015-02-01

Using the Sloan Digital Sky Survey, we examine the quenching of satellite galaxies around isolated Milky Way-like hosts in the local Universe. We find that the efficiency of satellite quenching around isolated galaxies is low and roughly constant over two orders of magnitude in satellite stellar mass (M⋆ = 108.5-1010.5 M⊙), with only ˜20 per cent of systems quenched as a result of environmental processes. While largely independent of satellite stellar mass, satellite quenching does exhibit clear dependence on the properties of the host. We show that satellites of passive hosts are substantially more likely to be quenched than those of star-forming hosts, and we present evidence that more massive haloes quench their satellites more efficiently. These results extend trends seen previously in more massive host haloes and for higher satellite masses. Taken together, it appears that galaxies with stellar masses larger than about 108 M⊙ are uniformly resistant to environmental quenching, with the relative harshness of the host environment likely serving as the primary driver of satellite quenching. At lower stellar masses (<108 M⊙), however, observations of the Local Group suggest that the vast majority of satellite galaxies are quenched, potentially pointing towards a characteristic satellite mass scale below which quenching efficiency increases dramatically.

Technology programs and related policies - Impacts on communications satellite business ventures

Science.gov (United States)

Greenberg, J. S.

1985-01-01

The DOMSAT II stochastic communication satellite business venture financial planning simulation model is described. The specification of business scenarios and the results of several analyses are presented. In particular, the impacts of NASA on-orbit propulsion and power technology programs are described. The effects of insurance rates and self-insurance and of the use of the Space Shuttle and Ariane transportation systems on a typical fixed satellite service business venture are discussed.

Merging Satellite Precipitation Products for Improved Streamflow Simulations

Science.gov (United States)

Maggioni, V.; Massari, C.; Barbetta, S.; Camici, S.; Brocca, L.

2017-12-01

Accurate quantitative precipitation estimation is of great importance for water resources management, agricultural planning and forecasting and monitoring of natural hazards such as flash floods and landslides. In situ observations are limited around the Earth, especially in remote areas (e.g., complex terrain, dense vegetation), but currently available satellite precipitation products are able to provide global precipitation estimates with an accuracy that depends upon many factors (e.g., type of storms, temporal sampling, season, etc.). The recent SM2RAIN approach proposes to estimate rainfall by using satellite soil moisture observations. As opposed to traditional satellite precipitation methods, which sense cloud properties to retrieve instantaneous estimates, this new bottom-up approach makes use of two consecutive soil moisture measurements for obtaining an estimate of the fallen precipitation within the interval between two satellite overpasses. As a result, the nature of the measurement is different and complementary to the one of classical precipitation products and could provide a different valid perspective to substitute or improve current rainfall estimates. Therefore, we propose to merge SM2RAIN and the widely used TMPA 3B42RT product across Italy for a 6-year period (2010-2015) at daily/0.25deg temporal/spatial scale. Two conceptually different merging techniques are compared to each other and evaluated in terms of different statistical metrics, including hit bias, threat score, false alarm rates, and missed rainfall volumes. The first is based on the maximization of the temporal correlation with a reference dataset, while the second is based on a Bayesian approach, which provides a probabilistic satellite precipitation estimate derived from the joint probability distribution of observations and satellite estimates. The merged precipitation products show a better performance with respect to the parental satellite-based products in terms of categorical

Impact of Rate Design Alternatives on Residential Solar Customer Bills. Increased Fixed Charges, Minimum Bills and Demand-based Rates

Energy Technology Data Exchange (ETDEWEB)

Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davidson, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); McLaren, Joyce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, John [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-09-01

With rapid growth in energy efficiency and distributed generation, electric utilities are anticipating stagnant or decreasing electricity sales, particularly in the residential sector. Utilities are increasingly considering alternative rates structures that are designed to recover fixed costs from residential solar photovoltaic (PV) customers with low net electricity consumption. Proposed structures have included fixed charge increases, minimum bills, and increasingly, demand rates - for net metered customers and all customers. This study examines the electricity bill implications of various residential rate alternatives for multiple locations within the United States. For the locations analyzed, the results suggest that residential PV customers offset, on average, between 60% and 99% of their annual load. However, roughly 65% of a typical customer's electricity demand is non-coincidental with PV generation, so the typical PV customer is generally highly reliant on the grid for pooling services.

A network architecture for International Business Satellite communications

Science.gov (United States)

Takahata, Fumio; Nohara, Mitsuo; Takeuchi, Yoshio

Demand Assignment (DA) control is expected to be introduced in the International Business Satellte communications (IBS) network in order to cope with a growing international business traffic. The paper discusses the DA/IBS network from the viewpoints of network configuration, satellite channel configuration and DA control. The network configuration proposed here consists of one Central Station with network management function and several Network Coordination Stations with user management function. A satellite channel configuration is also presented along with a tradeoff study on transmission bit rate, high power amplifier output power requirement, and service quality. The DA control flow and protocol based on CCITT Signalling System No. 7 are also proposed.

Robust satellite techniques for monitoring volcanic eruptions

Energy Technology Data Exchange (ETDEWEB)

Pergola, N.; Pietrapertosa, C. [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Avanzate, Tito Scalo, PZ (Italy); Lacava, T.; Tramutoli, V. [Potenza Universita' della Basilicata, Potenza (Italy). Dipt. di Ingegneria e Fisica dell' Ambiente

2001-04-01

Through this paper the robust approach to monitoring volcanic aerosols by satellite is applied to an extended set of events affecting Stromboli and Etna volcanoes to assess its performance in automated detection of eruptive clouds and in monitoring pre-eruptive emission activities. Using only NOAA/AVHRR data at hand (without any specific atmospheric model or ancillary ground-based measurements) the proposed method automatically discriminates meteorological from eruptive volcanic clouds and, in several cases, identified pre-eruptive anomalies in the emission rates not identified by traditional methods. The main merit of this approach is its effectiveness in recognising field anomalies also in the presence of a highly variable surface background as well as its intrinsic exportability not only on different geographic areas but also on different satellite instrumental packages. In particular, the possibility to extend the proposed method to the incoming new MSG/SEVIRI satellite package (which is going to fly next year) with its improved spectral (specific bands for SO{sub 2}) and temporal (up to 15 min) resolutions has been evaluated representing the natural continuation of this work.

SatelliteDL: a Toolkit for Analysis of Heterogeneous Satellite Datasets

Science.gov (United States)

Galloy, M. D.; Fillmore, D.

2014-12-01

SatelliteDL is an IDL toolkit for the analysis of satellite Earth observations from a diverse set of platforms and sensors. The core function of the toolkit is the spatial and temporal alignment of satellite swath and geostationary data. The design features an abstraction layer that allows for easy inclusion of new datasets in a modular way. Our overarching objective is to create utilities that automate the mundane aspects of satellite data analysis, are extensible and maintainable, and do not place limitations on the analysis itself. IDL has a powerful suite of statistical and visualization tools that can be used in conjunction with SatelliteDL. Toward this end we have constructed SatelliteDL to include (1) HTML and LaTeX API document generation,(2) a unit test framework,(3) automatic message and error logs,(4) HTML and LaTeX plot and table generation, and(5) several real world examples with bundled datasets available for download. For ease of use, datasets, variables and optional workflows may be specified in a flexible format configuration file. Configuration statements may specify, for example, a region and date range, and the creation of images, plots and statistical summary tables for a long list of variables. SatelliteDL enforces data provenance; all data should be traceable and reproducible. The output NetCDF file metadata holds a complete history of the original datasets and their transformations, and a method exists to reconstruct a configuration file from this information. Release 0.1.0 distributes with ingest methods for GOES, MODIS, VIIRS and CERES radiance data (L1) as well as select 2D atmosphere products (L2) such as aerosol and cloud (MODIS and VIIRS) and radiant flux (CERES). Future releases will provide ingest methods for ocean and land surface products, gridded and time averaged datasets (L3 Daily, Monthly and Yearly), and support for 3D products such as temperature and water vapor profiles. Emphasis will be on NPP Sensor, Environmental and

Satellite Application for Disaster Management Information Systems

Science.gov (United States)

Okpanachi, George

Abstract Satellites are becoming increasingly vital to modern day disaster management activities. Earth observation (EO) satellites provide images at various wavelengths that assist rapid-mapping in all phases of the disaster management cycle: mitigation of potential risks in a given area, preparedness for eventual disasters, immediate response to a disaster event, and the recovery/reconstruction efforts follo wing it. Global navigation satellite systems (GNSS) such as the Global Positioning System (GPS) assist all the phases by providing precise location and navigation data, helping manage land and infrastructures, and aiding rescue crews coordinate their search efforts. Effective disaster management is a complex problem, because it involves many parameters, which are usually not easy to measure and even identify: Analysis of current situation, planning, optimum resource management, coordination, controlling and monitoring current activities and making quick and correct decisions are only some of these parameters, whose complete list is very long. Disaster management information systems (DMIS) assist disaster management to analyse the situation better, make decisions and suggest further actions following the emergency plans. This requires not only fast and thorough processing and optimization abilities, but also real-time data provided to the DMIS. The need of DMIS for disaster’s real-time data can be satisfied by small satellites data utilization. Small satellites can provide up-to-data, plus a better media to transfer data. This paper suggests a rationale and a framework for utilization of small Satellite data by DMIS. DMIS should be used ‘’before’’, ‘’during’’ and ‘’after’’ the disasters. Data provided by the Small Satellites are almost crucial in any period of the disasters, because early warning can save lives, and satellite data may help to identify disasters before they occur. The paper also presents’ ‘when’’, �

Advancements in vibroacoustic evaluation of satellite structures

Science.gov (United States)

Stavrinidis, C.; Witting, M.; Ikoss, S. I.; Klein, M.

2001-02-01

The importance of the launcher vibroacoustic environment is increasing with respect to satellite loads due to the increase in size and decrease in surface mass of lightweight appendages like antennas and solar arrays. The loads generated by the vibroacoustic environment need to be covered adequately to ensure satellite structural integrity. This is of particular importance in the low-frequency range where the low frequencies of light appendages and equipment couple with the acoustic environment. In order to cope with the increasing demand for prediction of structural loads due to the acoustic environment, various methods have been developed in the frame of ESA research and development activities. These range from simplified approaches with partial fluid-structure coupling, e.g. the POSTAR package provided by INTESPACE (France) to more sophisticated approaches with full fluid-structure coupling. In the frequency domain this includes pure finite element modelling techniques, where specific tools have been developed by FFA (Sweden) using the ASKA package, as well as coupled finite element—boundary element approaches that have been developed in cooperation with DASA-Dornier (Germany), STRACO (France) and FFA using the commercial packages ASKA and RAYON. For fully coupled fluid structure analysis in the time domain the ASTRYD code from METRAVIB (France) is employed where advancements have been supported by CNES. Applications of these tools range from simple benchmarks such as simply supported plates, cavity enclosures or generic satellite-fairing models to complex satellite structure configurations. Evaluations of antenna reflector structures (Artemis communication antenna) and satellite equipment panels (polar platform) are presented. The paper covers also the investigation of payload/fairing effects (influence of fairing helium purging on the coupled-system response) together with DASA-Dornier, FFA and STRACO, as well as the vibroacoustic analysis of solar array

Response of Jupiter's Aurora to Plasma Mass Loading Rate Monitored by the Hisaki Satellite During Volcanic Eruptions at Io

Science.gov (United States)

Kimura, T.; Hiraki, Y.; Tao, C.; Tsuchiya, F.; Delamere, P. A.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kita, H.; Badman, S. V.; Fukazawa, K.; Yoshikawa, I.; Fujimoto, M.

2018-03-01

The production and transport of plasma mass are essential processes in the dynamics of planetary magnetospheres. At Jupiter, it is hypothesized that Io's volcanic plasma carried out of the plasma torus is transported radially outward in the rotating magnetosphere and is recurrently ejected as plasmoid via tail reconnection. The plasmoid ejection is likely associated with particle energization, radial plasma flow, and transient auroral emissions. However, it has not been demonstrated that plasmoid ejection is sensitive to mass loading because of the lack of simultaneous observations of both processes. We report the response of plasmoid ejection to mass loading during large volcanic eruptions at Io in 2015. Response of the transient aurora to the mass loading rate was investigated based on a combination of Hisaki satellite monitoring and a newly developed analytic model. We found that the transient aurora frequently recurred at a 2-6 day period in response to a mass loading increase from 0.3 to 0.5 t/s. In general, the recurrence of the transient aurora was not significantly correlated with the solar wind, although there was an exceptional event with a maximum emission power of 10 TW after the solar wind shock arrival. The recurrence of plasmoid ejection requires the precondition that an amount comparable to the total mass of magnetosphere, 1.5 Mt, is accumulated in the magnetosphere. A plasmoid mass of more than 0.1 Mt is necessary in case that the plasmoid ejection is the only process for mass release.

Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.; Hager, E. Paul

1991-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

78 FR 57099 - Avocados Grown in South Florida; Increased Assessment Rate

Science.gov (United States)

2013-09-17

... Service 7 CFR Part 915 [Doc. No. AMS-FV-13-0054; FV13-915-2 PR] Avocados Grown in South Florida; Increased... rule would increase the assessment rate established for the Avocado Administrative Committee (Committee... Florida avocados handled. The Committee locally administers the marketing order, which regulates the...

Is Increasing Coal Seam Gas Well Development Activity Associated with Increasing Hospitalisation Rates in Queensland, Australia? An Exploratory Analysis 1995-2011.

Science.gov (United States)

Werner, Angela K; Cameron, Cate M; Watt, Kerrianne; Vink, Sue; Jagals, Paul; Page, Andrew

2017-05-18

The majority of Australia's coal seam gas (CSG) reserves are in Queensland, where the industry has expanded rapidly in recent years. Despite concerns, health data have not been examined alongside CSG development. This study examined hospitalisation rates as a function of CSG development activity in Queensland, during the period 1995-2011. Admissions data were examined with CSG well numbers, which served as a proxy for CSG development activity. Time series models were used to assess changes in hospitalisation rates for periods of "low", "medium", "high", and "intense" activity compared to a period of "very low" activity, adjusting for covariates. "All-cause" hospitalisation rates increased monotonically with increasing gas well development activity in females (324.0 to 390.3 per 1000 persons) and males (294.2 to 335.4 per 1000 persons). Hospitalisation rates for "Blood/immune" conditions generally increased for both sexes. Female and male hospitalisation rates for "Circulatory" conditions decreased with increasing CSG activity. Hospitalisation rates were generally low for reproductive and birth outcomes; no clear associations were observed. This study showed some outcomes were associated with increasing CSG development activity. However, as a condition of data access, the population and outcomes were aggregated to a broad geographic study area rather than using higher geographic resolution data. Higher resolution data, as well as other data sources, should be explored. Further research should be conducted with an expanded time period to determine if these trends continue as the industry grows.

Satellite constraints on surface concentrations of particulate matter

Science.gov (United States)

Ford Hotmann, Bonne

Because of the increasing evidence of the widespread adverse effects on human health from exposure to poor air quality and the recommendations of the World Health Organization to significantly reduce PM2.5 in order to reduce these risks, better estimates of surface air quality globally are required. However, surface measurements useful for monitoring particulate exposure are scarce, especially in developing countries which often experience the worst air pollution. Therefore, other methods are necessary to augment estimates in regions with limited surface observations. The prospect of using satellite observations to infer surface air quality is attractive; however, it requires knowledge of the complicated relationship between satellite-observed aerosol optical depth (AOD) and surface concentrations. This dissertation explores how satellite observations can be used in conjunction with a chemical transport model (GEOS-Chem) to better understand this relationship. First, we investigate the seasonality in aerosols over the Southeastern United States using observations from several satellite instruments (MODIS, MISR, CALIOP) and surface network sites (IMPROVE, SEARCH, AERONET). We find that the strong summertime enhancement in satellite-observed aerosol optical depth (factor 2-3 enhancement over wintertime AOD) is not present in surface mass concentrations (25-55% summertime enhancement). Goldstein et al. [2009] previously attributed this seasonality in AOD to biogenic organic aerosol; however, surface observations show that organic aerosol only accounts for ~35% of PM2.5 mass and exhibits similar seasonality to total surface PM2.5. The GEOS-Chem model generally reproduces these surface aerosol measurements, but under represents the AOD seasonality observed by satellites. We show that seasonal differences in water uptake cannot sufficiently explain the magnitude of AOD increase. As CALIOP profiles indicate the presence of additional aerosol in the lower troposphere

Economics of satellite communications systems

Science.gov (United States)

Pritchard, Wilbur L.

This paper is partly a tutorial, telling systematically how one goes about calculating the total annual costs of a satellite communications system, and partly the expression of some original ideas on the choice of parameters so as to minimize these costs. The calculation of costs can be divided into two broad categories. The first is technical and is concerned with estimating what particular equipment will cost and what will be the annual expense to maintain and operate it. One starts in the estimation of any new system by listing the principal items of equipment, such as satellites, earth stations of various sizes and functions, telemetry and tracking equipment and terrestrial interfaces, and then estimating how much each item will cost. Methods are presented for generating such estimates, based on a knowledge of the gross parameters, such as antenna size, coverage area, transmitter power and information rate. These parameters determine the system performance and it is usually possible, knowing them, to estimate the costs of the equipment rather well. Some formulae based on regression analyses are presented. Methods are then given for estimating closely related expenses, such as maintenance and operation, and then an approximate method is developed for estimating terrestrial interconnection costs. It is pointed out that in specific cases when tariff and geographical information are available, it is usually better to work with specific data, but nonetheless it is often desirable, especially in global system estimating, to approximate these interconnect costs without recourse to individual tariffs. The procedure results in a set of costs for the purchase of equipment and its maintenance, and a schedule of payments. Some payments will be incurred during the manufacture of the satellite and before any systems operation, but many will not be incurred until the system is no longer in use, e.g. incentives. In any case, with the methods presented in the first section, one

Modeling and control of a gravity gradient stabilised satellite

Directory of Open Access Journals (Sweden)

Aage Skullestad

1999-01-01

Full Text Available This paper describes attitude control, i.e., 3-axes stabilisation and pointing, of a proposed Norwegian small gravity gradient stabilized satellite to be launched into low earth orbit. Generally, a gravity gradient stabilised system has limited stability and pointing capabilities, and wheels and/or magnetic coils are added in order to improve the attitude control. The best attitude accuracy is achieved using wheels, which can give accuracies down to less than one degree, but wheels increase the complexity and cost of the satellite. Magnetic coils allow cheaper satellites, and are an attractive solution to small, inexpensive satellites in low earth orbits and may provide an attitude control accuracy of a few degrees. Scientific measurements often require accurate attitude control in one or two axes only. Combining wheel and coil control may, in these cases, provide the best solutions. The simulation results are based on a linearised mathematical model of the satellite.

Development and control of a three-axis satellite simulator for the bifocal relay mirror initiative

OpenAIRE

Chernesky, Vincent S.

2001-01-01

The Three Axis Satellite Simulator (TASS) is a 4-foot diameter octagonal platform supported on a spherical air bearing. The platform hosts several satellite subsystems, including rate gyros, reaction wheels, thrusters, sun sensors, and an onboard control computer. This free-floating design allows for realistic emulation of satellite attitude dynamics in a laboratory environment. The bifocal relay mirror spacecraft system is composed of two optically coupled telescopes used to redirect the las...

Trajectory Planning of Satellite Formation Flying using Nonlinear Programming and Collocation

Directory of Open Access Journals (Sweden)

Hyung-Chu Lim

2008-12-01

Full Text Available Recently, satellite formation flying has been a topic of significant research interest in aerospace society because it provides potential benefits compared to a large spacecraft. Some techniques have been proposed to design optimal formation trajectories minimizing fuel consumption in the process of formation configuration or reconfiguration. In this study, a method is introduced to build fuel-optimal trajectories minimizing a cost function that combines the total fuel consumption of all satellites and assignment of fuel consumption rate for each satellite. This approach is based on collocation and nonlinear programming to solve constraints for collision avoidance and the final configuration. New constraints of nonlinear equality or inequality are derived for final configuration, and nonlinear inequality constraints are established for collision avoidance. The final configuration constraints are that three or more satellites should form a projected circular orbit and make an equilateral polygon in the horizontal plane. Example scenarios, including these constraints and the cost function, are simulated by the method to generate optimal trajectories for the formation configuration and reconfiguration of multiple satellites.

Fast Faraday fading of long range satellite signals.

Science.gov (United States)

Heron, M. L.

1972-01-01

20 MHz radio signals have been received during the day from satellite Beacon-B when it was below the optical horizon by using a bank of narrow filters to improve the signal to noise ratio. The Faraday fading rate becomes constant, under these conditions, at a level determined by the plasma frequency just below the F-layer peak. Variations in the Faraday fading rate reveal fluctuations in the electron density near the peak, while the rate of attaining the constant level depends on the shape of the electron density profile.

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

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

The Antarctic Ice Sheet, Sea Ice, and the Ozone Hole: Satellite Observations of how they are Changing

Science.gov (United States)

Parkinson, Claire L.

2012-01-01

Antarctica is the Earth's coldest and highest continent and has major impacts on the climate and life of the south polar vicinity. It is covered almost entirely by the Earth's largest ice sheet by far, with a volume of ice so great that if all the Antarctic ice were to go into the ocean (as ice or liquid water), this would produce a global sea level rise of about 60 meters (197 feet). The continent is surrounded by sea ice that in the wintertime is even more expansive than the continent itself and in the summertime reduces to only about a sixth of its wintertime extent. Like the continent, the expansive sea ice cover has major impacts, reflecting the sun's radiation back to space, blocking exchanges between the ocean and the atmosphere, and providing a platform for some animal species while impeding other species. Far above the continent, the Antarctic ozone hole is a major atmospheric phenomenon recognized as human-caused and potentially quite serious to many different life forms. Satellites are providing us with remarkable information about the ice sheet, the sea ice, and the ozone hole. Satellite visible and radar imagery are providing views of the large scale structure of the ice sheet never seen before; satellite laser altimetry has produced detailed maps of the topography of the ice sheet; and an innovative gravity-measuring two-part satellite has allowed mapping of regions of mass loss and mass gain on the ice sheet. The surrounding sea ice cover has a satellite record that goes back to the 1970s, allowing trend studies that show a decreasing sea ice presence in the region of the Bellingshausen and Amundsen seas, to the west of the prominent Antarctic Peninsula, but increasing sea ice presence around much of the rest of the continent. Overall, sea ice extent around Antarctica has increased at an average rate of about 17,000 square kilometers per year since the late 1970s, as determined from satellite microwave data that can be collected under both light and

Combined Geometric and Neural Network Approach to Generic Fault Diagnosis in Satellite Actuators and Sensors

DEFF Research Database (Denmark)

Baldi, P.; Blanke, Mogens; Castaldi, P.

2016-01-01

This paper presents a novel scheme for diagnosis of faults affecting the sensors measuring the satellite attitude, body angular velocity and flywheel spin rates as well as defects related to the control torques provided by satellite reaction wheels. A nonlinear geometric design is used to avoid t...

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.

The American Satellite Company (ASC) satellite deployed from payload bay

Science.gov (United States)

1985-01-01

The American Satellite Company (ASC) communications satellite is deployed from the payload bay of the Shuttle Discovery. A portion of the cloudy surface of the earth can be seen to the left of the frame.

A Feasible Approach for Implementing Greater Levels of Satellite Autonomy

Science.gov (United States)

Lindsay, Steve; Zetocha, Paul

2002-01-01

In this paper, we propose a means for achieving increasingly autonomous satellite operations. We begin with a brief discussion of the current state-of-the-art in satellite ground operations and flight software, as well as the real and perceived technical and political obstacles to increasing the levels of autonomy on today's satellites. We then present a list of system requirements that address these hindrances and include the artificial intelligence (AI) technologies with the potential to satisfy these requirements. We conclude with a discussion of how the space industry can use this information to incorporate increased autonomy. From past experience we know that autonomy will not just "happen," and we know that the expensive course of manually intensive operations simply cannot continue. Our goal is to present the aerospace industry with an analysis that will begin moving us in the direction of autonomous operations.

Software defined radio (SDR) architecture for concurrent multi-satellite communications

Science.gov (United States)

Maheshwarappa, Mamatha R.

SDRs have emerged as a viable approach for space communications over the last decade by delivering low-cost hardware and flexible software solutions. The flexibility introduced by the SDR concept not only allows the realisation of concurrent multiple standards on one platform, but also promises to ease the implementation of one communication standard on differing SDR platforms by signal porting. This technology would facilitate implementing reconfigurable nodes for parallel satellite reception in Mobile/Deployable Ground Segments and Distributed Satellite Systems (DSS) for amateur radio/university satellite operations. This work outlines the recent advances in embedded technologies that can enable new communication architectures for concurrent multi-satellite or satellite-to-ground missions where multi-link challenges are associated. This research proposes a novel concept to run advanced parallelised SDR back-end technologies in a Commercial-Off-The-Shelf (COTS) embedded system that can support multi-signal processing for multi-satellite scenarios simultaneously. The initial SDR implementation could support only one receiver chain due to system saturation. However, the design was optimised to facilitate multiple signals within the limited resources available on an embedded system at any given time. This was achieved by providing a VHDL solution to the existing Python and C/C++ programming languages along with parallelisation so as to accelerate performance whilst maintaining the flexibility. The improvement in the performance was validated at every stage through profiling. Various cases of concurrent multiple signals with different standards such as frequency (with Doppler effect) and symbol rates were simulated in order to validate the novel architecture proposed in this research. Also, the architecture allows the system to be reconfigurable by providing the opportunity to change the communication standards in soft real-time. The chosen COTS solution provides a

Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate

Directory of Open Access Journals (Sweden)

Aldo Compagnoni

2014-01-01

Full Text Available Abstract Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1 warming increases cheatgrass population growth rate and 2 reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.

ORBITAL DEPENDENCE OF GALAXY PROPERTIES IN SATELLITE SYSTEMS OF GALAXIES

International Nuclear Information System (INIS)

Hwang, Ho Seong; Park, Changbom

2010-01-01

We study the dependence of satellite galaxy properties on the distance to the host galaxy and the orbital motion (prograde and retrograde orbits) using the Sloan Digital Sky Survey (SDSS) data. From SDSS Data Release 7, we find 3515 isolated satellite systems of galaxies at z -1 . It is found that the radial distribution of early-type satellites in prograde orbit is strongly concentrated toward the host while that of retrograde ones shows much less concentration. We also find the orbital speed of late-type satellites in prograde orbit increases as the projected distance to the host (R) decreases while the speed decreases for those in retrograde orbit. At R less than 0.1 times the host virial radius (R vir,host ), the orbital speed decreases in both prograde and retrograde orbit cases. Prograde satellites are on average fainter than retrograde satellites for both early and late morphological types. The u - r color becomes redder as R decreases for both prograde and retrograde orbit late-type satellites. The differences between prograde and retrograde orbit satellite galaxies may be attributed to their different origin or the different strength of physical processes that they have experienced through hydrodynamic interactions with their host galaxies.

The Chinese FY-1 Meteorological Satellite Application in Observation on Oceanic Environment

Science.gov (United States)

Weimin, S.

meteorological satellite is stated in this paper. exploration of the ocean resources has been a very important question of global strategy in the world. The exploration of the ocean resources includes following items: Making full use of oceanic resources and space, protecting oceanic environment. to observe the ocean is by using of satellite. In 1978, US successfully launched the first ocean observation satellite in the world --- Sea Satellite. It develops ancient oceanography in to advanced space-oceanography. FY-1 B and FY- IC respectively. High quality data were acquired at home and abroad. FY-1 is Chinese meteorological satellite, but with 0.43 ~ 0.48 μm ,0.48 ~ 0.53 μm and 0.53 ~ 0.58 μm three ocean color channels, actually it is a multipurpose remote sensing satellite of meteorology and oceanography. FY-1 satellite's capability of observation on ocean partly, thus the application field is expanded and the value is increased. With the addition of oceanic channels on FY-1, the design of the satellite is changed from the original with meteorological observation as its main purpose into remote sensing satellite possessing capability of observing meteorology and ocean as well. Thus, the social and economic benefit of FY-1 is increased. the social and economic benefit of the development of the satellite is the key technique in the system design of the satellite. technically feasible but also save the funds in researching and manufacturing of the satellite, quicken the tempo of researching and manufacturing satellite. the scanning radiometer for FY-1 is conducted an aviation experiment over Chinese ocean. This experiment was of vital importance to the addition of oceanic observation channel on FY-1. FY-1 oceanic channels design to be correct. detecting ocean color. This is the unique character of Chinese FY-1 meteorological satellite. meteorological remote sensing channel on FY-1 to form detecting capability of three visible channels: red, yellow and blue

Asian Dust Weather Categorization with Satellite and Surface Observations

Science.gov (United States)

Lin, Tang-Huang; Hsu, N. Christina; Tsay, Si-Chee; Huang, Shih-Jen

2011-01-01

This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved aerosol optical properties and surface visibility, the intensity of dust weather can be more effectively and consistently discerned using satellite rather than surface observations. In this article, datasets consisting of collocated products from Moderate Resolution Imaging Spectroradiometer Aqua and surface measurements are analysed. The results indicate an exponential relationship between the surface visibility and the satellite-retrieved aerosol optical depth, which is subsequently used to categorize the dust weather. The satellite-derived spatial frequency distributions in the dust weather types are consistent with China s weather station reports during 2003, indicating that dust weather classification using satellite data is highly feasible. Although the period during the springtime from 2004 to 2007 may be not sufficient for statistical significance, our results reveal an increasing tendency in both intensity and frequency of dust weather over central Asia during this time period.

Satellite-based Flood Modeling Using TRMM-based Rainfall Products

Directory of Open Access Journals (Sweden)

Greg Easson

2007-12-01

Full Text Available Increasingly available and a virtually uninterrupted supply of satellite-estimatedrainfall data is gradually becoming a cost-effective source of input for flood predictionunder a variety of circumstances. However, most real-time and quasi-global satelliterainfall products are currently available at spatial scales ranging from 0.25o to 0.50o andhence, are considered somewhat coarse for dynamic hydrologic modeling of basin-scaleflood events. This study assesses the question: what are the hydrologic implications ofuncertainty of satellite rainfall data at the coarse scale? We investigated this question onthe 970 km2 Upper Cumberland river basin of Kentucky. The satellite rainfall productassessed was NASA’s Tropical Rainfall Measuring Mission (TRMM Multi-satellitePrecipitation Analysis (TMPA product called 3B41RT that is available in pseudo real timewith a latency of 6-10 hours. We observed that bias adjustment of satellite rainfall data canimprove application in flood prediction to some extent with the trade-off of more falsealarms in peak flow. However, a more rational and regime-based adjustment procedureneeds to be identified before the use of satellite data can be institutionalized among floodmodelers.

[Voluntary alpha-power increasing training impact on the heart rate variability].

Science.gov (United States)

Bazanova, O M; Balioz, N V; Muravleva, K B; Skoraia, M V

2013-01-01

In order to study the effect of the alpha EEG power increasing training at heart rate variability (HRV) as the index of the autonomic regulation of cognitive functions there were follow tasks: (1) to figure out the impact of biofeedback in the voluntary increasing the power in the individual high-frequency alpha-band effect on heart rate variability and related characteristics of cognitive and emotional spheres, (2) to determine the nature of the relationship between alpha activity indices and heart rate variability, depending on the alpha-frequency EEG pattern at rest (3) to examine how the individual alpha frequency EEG pattern is reflected in changes HRV as a result of biofeedback training. Psychometric indicators of cognitive performance, the characteristics of the alpha-EEG activity and heart rate variability (HRV) as LF/HF and pNN50 were recorded in 27 healthy men aged 18-34 years, before, during, and after 10 sessions of training of voluntary increase in alpha power in the individual high-frequency alpha band with eyes closed. To determine the biofeedback effect on the alpha power increasing training, data subjects are compared in 2 groups: experimental (14) with the real and the control group (13 people)--with mock biofeedback. The follow up effect of trainings was studied through month over the 10 training sessions. Results showed that alpha biofeedback training enhanced the fluency and accuracy in cognitive performance, decreased anxiety and frontal EMG, increased resting frequency, width and power in individual upper alpha range only in participants with low baseline alpha frequency. While mock biofeedback increased resting alpha power only in participants with high baseline resting alpha frequency and did change neither cognitive performance, nor HRV indices. Biofeedback training eliminated the alpha power decrease in response to arithmetic task in both with high and low alpha frequency participants and this effect was followed up over the month. Mock

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.

JPSS Preparations at the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis

Science.gov (United States)

Folmer, Michael J.; Berndt, E.; Clark, J.; Orrison, A.; Kibler, J.; Sienkiewicz, J.; Nelson, J.; Goldberg, M.; Sjoberg, W.

2016-01-01

The ocean prediction center at the national hurricane center's tropical analysis and forecast Branch, the Weather Prediction center and the Satellite analysis branch of NESDIS make up the Satellite Proving Ground for Marine, Precipitation and Satellite Analysis. These centers had early exposure to JPSS products using the S-NPP Satellite that was launched in 2011. Forecasters continue to evaluate new products in anticipation for the launch of JPSS-1 sometime in 2017.

Changes in transcriptional orientation are associated with increases in evolutionary rates of enterobacterial genes

Directory of Open Access Journals (Sweden)

Hsiung Chao

2011-10-01

Full Text Available Abstract Background Changes in transcriptional orientation (“CTOs” occur frequently in prokaryotic genomes. Such changes usually result from genomic inversions, which may cause a conflict between the directions of replication and transcription and an increase in mutation rate. However, CTOs do not always lead to the replication-transcription confrontation. Furthermore, CTOs may cause deleterious disruptions of operon structure and/or gene regulations. The currently existing CTOs may indicate relaxation of selection pressure. Therefore, it is of interest to investigate whether CTOs have an independent effect on the evolutionary rates of the affected genes, and whether these genes are subject to any type of selection pressure in prokaryotes. Methods Three closely related enterbacteria, Escherichia coli, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium, were selected for comparisons of synonymous (dS and nonsynonymous (dN substitution rate between the genes that have experienced changes in transcriptional orientation (changed-orientation genes, “COGs” and those that do not (same-orientation genes, “SOGs”. The dN/dS ratio was also derived to evaluate the selection pressure on the analyzed genes. Confounding factors in the estimation of evolutionary rates, such as gene essentiality, gene expression level, replication-transcription confrontation, and decreased dS at gene terminals were controlled in the COG-SOG comparisons. Results We demonstrate that COGs have significantly higher dN and dS than SOGs when a series of confounding factors are controlled. However, the dN/dS ratios are similar between the two gene groups, suggesting that the increase in dS can sufficiently explain the increase in dN in COGs. Therefore, the increases in evolutionary rates in COGs may be mainly mutation-driven. Conclusions Here we show that CTOs can increase the evolutionary rates of the affected genes. This effect is independent of the

The satellite situation center

International Nuclear Information System (INIS)

Teague, M.J.; Sawyer, D.M.; Vette, J.I.

1982-01-01

Considerations related to the early planning for the International Magnetospheric Study (IMS) took into account the desirability of an establishment of specific entities for generating and disseminating coordination information for both retrospective and predictive periods. The organizations established include the IMS/Satellite Situation Center (IMS/SSC) operated by NASA. The activities of the SSC are related to the preparation of reports on predicted and actually achieved satellite positions, the response to inquiries, the compilation of information on satellite experiments, and the issue of periodic status summaries. Attention is given to high-altitude satellite services, other correlative satellite services, non-IMS activities of the SSC, a summary of the SSC request activity, and post-IMS and future activities

Plan of Time Management of Satellite Positioning System using Quasi-zenith Satellite

Science.gov (United States)

Takahashi, Yasuhiro; Fujieda, Miho; Amagai, Jun; Yokota, Shoichiro; Kimura, Kazuhiro; Ito, Hiroyuki; Hama, Shin'ichi; Morikawa, Takao; Kawano, Isao; Kogure, Satoshi

The Quasi-Zenith satellites System (QZSS) is developed as an integrated satellite service system of communication, broadcasting and positioning for mobile users in specified regions of Japan from high elevation angle. Purposes of the satellite positioning system using Quasi-Zenith satellite (QZS) are to complement and augment the GPS. The national institutes concerned have been developing the positioning system using QZS since 2003 and will carry out experiments and researches in three years after the launch. In this system, National Institute of Information and Communications Technology (NICT) is mainly in charge of timing system for the satellite positioning system using QZS, such as onboard hydrogen maser atomic clock and precise time management system of the QZSS. We started to develop the engineering model of the time management system for the QZSS. The time management system for the QZSS will be used to compare time differences between QZS and earth station as well as to compare between three onboard atomic clocks. This paper introduces time management of satellite positioning system using the QZSS.

75 FR 22211 - Olives Grown in California; Increased Assessment Rate

Science.gov (United States)

2010-04-28

... Executive Order 12988, Civil Justice Reform. Under the marketing order now in effect, California olive... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 932 [Doc. No. AMS-FV-09-0089; FV10-932-1 FR] Olives Grown in California; Increased Assessment Rate AGENCY: Agricultural Marketing...

76 FR 67320 - Walnuts Grown in California; Increased Assessment Rate

Science.gov (United States)

2011-11-01

... Justice Reform. Under the marketing order now in effect, California walnut handlers are subject to... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 984 [Doc. No. AMS-FV-11-0062; FV11-984-1 FR] Walnuts Grown in California; Increased Assessment Rate AGENCY: Agricultural Marketing...

77 FR 51684 - Olives Grown in California; Increased Assessment Rate

Science.gov (United States)

2012-08-27

... 12988, Civil Justice Reform. Under the marketing order now in effect, California olive handlers are... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 932 [Doc. No. AMS-FV-11-0093; FV12-932-1 FR] Olives Grown in California; Increased Assessment Rate AGENCY: Agricultural Marketing...

Satellite observation of particulate organic carbon dynamics in ...

Science.gov (United States)

Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical processes that influence POC sources and sinks. Using field observations and satellite ocean color products, we developed a nw multiple regression algorithm to estimate POC on the Louisiana Continental Shelf (LCS) from satellite observations. The algorithm had reliable performance with mean relative error (MRE) of ?40% and root mean square error (RMSE) of ?50% for MODIS and SeaWiFS images for POC ranging between ?80 and ?1200 mg m23, and showed similar performance for a large estuary (Mobile Bay). Substantial spatiotemporal variability in the satellite-derived POC was observed on the LCS, with high POC found on the inner shelf (satellite data with carefully developed algorithms can greatly increase

Radial diffusion in the Uranian radiatian belts - Inferences from satellite absorption loss models

Science.gov (United States)

Hood, L. L.

1989-01-01

Low-energy charged particle (LECP) phase space density profiles available from the Voyager/1986 Uranus encounter are analyzed, using solutions of the time-averaged radial diffusion equation for charged particle transport in a dipolar planetary magnetic field. Profiles for lower-energy protons and electrons are first analyzed to infer radial diffusion rate as a function of L, assuming that satellite absorption is the dominant loss process and local sources for these particles are negligible. Satellite macrosignatures present in the experimentally derived profiles are approximately reproduced in several cases, lending credence to the loss model and indicating that magnetospheric distributed losses are not as rapid as satellite absorption near the minimum satellite L shells for the particles. Diffusion rates and L dependences are found to be similar to those previously inferred in the inner Jovian magnetosphere (Thomsen et al., 1977) and for the inner Saturnian magnetosphere (Hood, 1985). Profiles for higher energy electrons and protons are also analyzed using solutions that allow for the existence of significant particle sources as well as sinks. Possible implications for radial diffusion mechanisms in the Uranian radiation belts are discussed.

Hyper Hospital on the satellite multi-media network.

Science.gov (United States)

Yamaguchi, T

1997-01-01

We have been developing the Hyper Hospital, a network based VR mediated medical care system. The Hyper Hospital is composed of two seamlessly integrated environments, that is, the virtual and the real worlds. Of them, its virtual environment expands the conventional medical care system using the virtual reality technology as a principal human interface and a collaboration tool, in the present study, an attempt to extend the Hyper Hospital system to various modalities of communication network is reported. A satellite communication based multi-media network using Internet protocols with the WWW interface is used. Data transmission rate and other performances were measured under various conditions and the satellite network was shown to be suitable to the Hyper Hospital network.

Increased Frame Rate for Plane Wave Imaging Without Loss of Image Quality

DEFF Research Database (Denmark)

Jensen, Jonas; Stuart, Matthias Bo; Jensen, Jørgen Arendt

2015-01-01

Clinical applications of plane wave imaging necessitate the creation of high-quality images with the highest possible frame rate for improved blood flow tracking and anatomical imaging. However, linear array transducers create grating lobe artefacts, which degrade the image quality especially...... in the near field for λ-pitch transducers. Artefacts can only partly be suppressed by increasing the number of emissions, and this paper demonstrates how the frame rate can be increased without loss of image quality by using λ/2-pitch transducers. The number of emissions and steering angles are optimized...

EFFECTS OF VOLUNTARY WHEEL RUNNING ON SATELLITE CELLS IN THE RAT PLANTARIS MUSCLE

Directory of Open Access Journals (Sweden)

Atsushi Kojima

2009-03-01

Full Text Available This study investigated the effects of voluntary wheel running on satellite cells in the rat plantaris muscle. Seventeen 5-week-old male Wistar rats were assigned to a control (n = 5 or training (n = 12 group. Each rat in the training group ran voluntarily in a running-wheel cage for 8 weeks. After the training period, the animals were anesthetized, and the plantaris muscles were removed, weighed, and analyzed immunohistochemically and biochemically. Although there were no significant differences in muscle weight or fiber area between the groups, the numbers of satellite cells and myonuclei per muscle fiber, percentage of satellite cells, and citrate synthase activity were significantly higher in the training group compared with the control group (p < 0.05. The percentage of satellite cells was also positively correlated with distance run in the training group (r = 0.61, p < 0.05. Voluntary running can induce an increase in the number of satellite cells without changing the mean fiber area in the rat plantaris muscle; this increase in satellite cell content is a function of distance run

Muscle satellite cells are activated after exercise to exhaustion in Thoroughbred horses.

Science.gov (United States)

Kawai, M; Aida, H; Hiraga, A; Miyata, H

2013-07-01

Although satellite cells are well known as muscle stem cells capable of adding myonuclei during muscle repair and hypertrophy, the response of satellite cells in horse muscles to a run to exhaustion is still unknown. To investigate the time course of satellite cell activation in Thoroughbred horse muscle after running to exhaustion. We hypothesised that this type of intense exercise would induce satellite cell activation in skeletal muscle similar to a resistance exercise. Nine de-trained Thoroughbred horses (6 geldings and 3 mares) aged 3-6 years were studied. Biopsy samples were taken from the gluteus medius muscle of the horses before and 1 min, 3 h, 1 day, 3 days, 1 week and 2 weeks after a treadmill run to exhaustion. The numbers of satellite cells for each fibre type were determined by using immunofluorescence staining. Total RNA was extracted from these samples, and the expressions of interleukin (IL)-6, paired box transcriptional factor (Pax) 7, myogenic differentiation 1 (MyoD), myogenin, proliferating cell nuclear antigen (PCNA), insulin-like growth factor (IGF)-I and hepatocyte growth factor (HGF) mRNA were analysed using real-time reverse transcription-PCR. The numbers of satellite cells were significantly increased in type I and IIa fibres at 1 week and in type IIa/x fibre at 2 weeks post exercise. The expression of IL-6 mRNA increased significantly by 3 h post exercise. The expression of PCNA mRNA also increased by 1 day after running, indicating that running can initiate satellite cell proliferation. The expression of Pax7, MyoD, myogenin, IGF-I and HGF mRNA peaked at 1 week post exercise. Satellite cell activation and proliferation could be enhanced after a run to exhaustion without detectable injury as assessed by the histochemical analysis. Understanding the response of satellite cell activation to running exercise provides fundamental information about the skeletal muscle adaptation in Thoroughbred horses. © 2012 EVJ Ltd.

Creatine supplementation augments the increase in satellite cell and myonuclei number in human skeletal muscle induced by strength training

DEFF Research Database (Denmark)

Olsen, Steen; Aagaard, Per; Kadi, Fawzi

2006-01-01

The present study investigated the influence of creatine and protein supplementation on satellite cell frequency and number of myonuclei in human skeletal muscle during 16 weeks of heavy-resistance training. In a double-blinded design 32 healthy, male subjects (19-26 years) were assigned to stren......The present study investigated the influence of creatine and protein supplementation on satellite cell frequency and number of myonuclei in human skeletal muscle during 16 weeks of heavy-resistance training. In a double-blinded design 32 healthy, male subjects (19-26 years) were assigned...

Communications satellite business ventures - Measuring the impact of technology programmes and related policies

Science.gov (United States)

Greenberg, J. S.

1986-01-01

An economic evaluation and planning procedure which assesses the effects of various policies on fixed satellite business ventures is described. The procedure is based on a stochastic financial simulation model, the Domsat II, which evaluates spacecraft reliability, market performance, and cost uncertainties. The application of the Domsat II model to the assessment of NASA's ion thrusters for on-orbit propulsion and GaAs solar cell technology is discussed. The effects of insurance rates and the self-insurance option on the financial performance of communication satellite business ventures are investigated. The selection of a transportation system for placing the satellites into GEO is analyzed.

Expanding Access with Satellite-Enabled Distance Education

Directory of Open Access Journals (Sweden)

Qi Wang

2006-12-01

Full Text Available Education and training became increasingly critical for citizens of every nation during the last century, and that paradigm will be no less true, throughout the 21st Century. As the world progresses fully into an information society, access to information and to a knowledge-based work force is a precondition for any country to remain competitive. Education, and increasingly distant education (DE, plays a vital role in turning human resources into knowledge workers. Information and communications technologies (ICT have provided new ways to educate and to disseminate information that is crucial for creating these competitive, knowledge-based work forces. Modern DE, enabled by ICT-based networks and the Internet tools, offers great advantages that are leveling the global playing field, in terms of providing access and opportunities for specialized training and education. Using satellite technology in DE may be imperative to developing countries, where the majority of their populations are scattered in rural and remote areas. Where the traditional brick and mortar classrooms cannot easily reach, satellite-powered DE systems can. Through literature review and rational analysis, this paper examines how satellite-assisted DE systems expand education access.

Increasing recruitment rates in an inpatient clinical research study using quality improvement methods.

Science.gov (United States)

Sauers, Hadley S; Beck, Andrew F; Kahn, Robert S; Simmons, Jeffrey M

2014-11-01

One important benefit of successful patient recruitment is increased generalizability of findings. We sought to optimize enrollment of children admitted with asthma as part of a population-based, prospective, observational cohort study with the goal of enrolling at least 60% of all eligible and staffed patients. Quality improvement methods were used to improve cohort recruitment. Weekly meetings with study staff and study leadership were held to plan and discuss how to maximize recruitment rates. Significant initial variability in recruitment success prompted the team to use small-scale tests of change to increase recruitment numbers. A number of tests were trialed, focusing primarily on reducing patient refusals and improving recruitment process efficiency. Recruitment rates were calculated by dividing eligible by enrolled patients and displayed using annotated Shewhart control charts. Control charts were used to illustrate week-to-week variability while also enabling differentiation of common-cause and special-cause variation. The study enrolled 774 patients, representing 54% of all eligible and 59% of those eligible for whom staff were available to enroll. Our mean weekly recruitment rate increased from 55% during the first 3 months of the study to a statistically significant sustained rate of 61%. This was sustained given numerous obstacles, such as departing and hiring of staff and adding a second recruitment location. Implementing quality improvement methods within a larger research study led to an increase in the rate of recruitment as well as the stability in recruitment rates from week-to-week. Copyright © 2014 by the American Academy of Pediatrics.

Anti-jamming Technology in Small Satellite Communication

Science.gov (United States)

Jia, Zixiang

2018-01-01

Small satellite communication has an increasingly important position among the wireless communications due to the advantages of low cost and high technology. However, in view of the case that its relay station stays outside the earth, its uplink may face interference from malicious signal frequently. Here this paper classified enumerates existing interferences, and proposes channel signals as main interference by comparison. Based on a basic digital communication process, then this paper discusses the possible anti - jamming techniques that commonly be realized at all stages in diverse processes, and comes to the conclusion that regarding the spread spectrum technology and antenna anti-jamming technology as fundamental direction of future development. This work provides possible thought for the design of new small satellite communication system with the coexistence of multi - technologies. This basic popular science can be consulted for people interested in small satellite communication.

An Improved BeiDou-2 Satellite-Induced Code Bias Estimation Method

Directory of Open Access Journals (Sweden)

Jingyang Fu

2018-04-01

Full Text Available Different from GPS, GLONASS, GALILEO and BeiDou-3, it is confirmed that the code multipath bias (CMB, which originate from the satellite end and can be over 1 m, are commonly found in the code observations of BeiDou-2 (BDS IGSO and MEO satellites. In order to mitigate their adverse effects on absolute precise applications which use the code measurements, we propose in this paper an improved correction model to estimate the CMB. Different from the traditional model which considering the correction values are orbit-type dependent (estimating two sets of values for IGSO and MEO, respectively and modeling the CMB as a piecewise linear function with a elevation node separation of 10°, we estimate the corrections for each BDS IGSO + MEO satellite on one hand, and a denser elevation node separation of 5° is used to model the CMB variations on the other hand. Currently, the institutions such as IGS-MGEX operate over 120 stations which providing the daily BDS observations. These large amounts of data provide adequate support to refine the CMB estimation satellite by satellite in our improved model. One month BDS observations from MGEX are used for assessing the performance of the improved CMB model by means of precise point positioning (PPP. Experimental results show that for the satellites on the same orbit type, obvious differences can be found in the CMB at the same node and frequency. Results show that the new correction model can improve the wide-lane (WL ambiguity usage rate for WL fractional cycle bias estimation, shorten the WL and narrow-lane (NL time to first fix (TTFF in PPP ambiguity resolution (AR as well as improve the PPP positioning accuracy. With our improved correction model, the usage of WL ambiguity is increased from 94.1% to 96.0%, the WL and NL TTFF of PPP AR is shorten from 10.6 to 9.3 min, 67.9 to 63.3 min, respectively, compared with the traditional correction model. In addition, both the traditional and improved CMB model have

Simobiz-Simulation Tool to Study the Impact of Small Satellites in Mobile Market

Science.gov (United States)

Burlacu, M.-M.; Kohlenberg, J.; Prathaban, M.

2008-08-01

Interest in small satellites is growing fast world- wide. Businesses, governments, universities and other organizations around the world are starting their own small satellite programs. The surveys conducted by the space agencies and universities shows a promising increase in the use of small satellites for commercial applications. More number of operators offers or plans to offer mobile phone services by satellite. With the help of cost effective small satellite, mobile operators can be able to provide the services cheaper. Hence, it is always interesting to study the effect of low cost small satellite over the mobile market. In this article, we present SmartSim (Small Satellites Mobile Market Simulator) - the new module of Simobiz business simulation game, in which we have implemented two operators, a normal satellite operator and a nanosatellite operator, with specific terminals and services. Our main focus in this work is to understand the future market of small satellite in mobile telecommunication network.

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.

Effectiveness of worksite interventions to increase influenza vaccination rates among employees and families.

Science.gov (United States)

Ofstead, Cori L; Sherman, Bruce W; Wetzler, Harry P; Dirlam Langlay, Alexandra M; Mueller, Natalie J; Ward, Jeremy M; Ritter, Daniel R; Poland, Gregory A

2013-02-01

To increase influenza vaccination rates among industrial employees and their families through a campaign at a large corporation. This prospective, multisite study used employee surveys and claims data to evaluate an evidence-based worksite vaccination program. Vaccination rates among insured employees and dependents (N = 13,520) increased significantly after the intervention (P employees received vaccine at employer-sponsored events. There was a strong association between employee and family vaccination status. Primary reasons for receiving the vaccine were economic (free 84%; convenient 80%; avoid absenteeism 82%), rather than health-related. Knowledge was associated with vaccination, but customized education did not change beliefs. Worksite programs can demonstrably increase vaccination rates among industrial employees and families. Consideration should be given to repositioning vaccination from medical treatment to community initiatives offered with other worksite health promotion programs.

Proceedings of the Fifth International Mobile Satellite Conference 1997

Science.gov (United States)

Jedrey, T. (Compiler); Rigley, J. (Compiler); Anderson, Louise (Editor)

1997-01-01

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments.

Effect of TCEA3 on the differentiation of bovine skeletal muscle satellite cells

International Nuclear Information System (INIS)

Zhu, Yue; Tong, Hui-Li; Li, Shu-Feng; Yan, Yun-Qin

2017-01-01

Bovine muscle-derived satellite cells (MDSCs) are important for animal growth. In this study, the effect of transcription elongation factor A3 (TCEA3) on bovine MDSC differentiation was investigated. Western blotting, immunofluorescence assays, and cytoplasmic and nuclear protein isolation and purification techniques were used to determine the expression pattern and protein localization of TCEA3 in bovine MDSCs during in vitro differentiation. TCEA3 expression was upregulated using the CRISPR/Cas9 technique to study its effects on MDSC differentiation in vitro. TCEA3 expression gradually increased during the in vitro differentiation of bovine MDSCs and peaked on the 5th day of differentiation. TCEA3 was mainly localized in the cytoplasm of bovine MDSCs, and its expression was not detected in the nucleus. The level of TCEA3 was relatively higher in myotubes at a higher degree of differentiation than during early differentiation. After transfection with a TCEA3-activating plasmid vector (TCEA3 overexpression) for 24 h, the myotube fusion rate, number of myotubes, and expression levels of the muscle differentiation-related loci myogenin (MYOG) and myosin heavy chain 3 (MYH3) increased significantly during the in vitro differentiation of bovine MDSCs. After transfection with a TCEA3-inhibiting plasmid vector for 24 h, the myotube fusion rate, number of myotubes, and expression levels of MYOG and MYH3 decreased significantly. Our results indicated, for the first time, that TCEA3 promotes the differentiation of bovine MDSCs and have implications for meat production and animal rearing. - Highlights: • Muscle-derived satellite cell differentiation is promoted by TCEA3. • TCEA3 protein was localized in the cytoplasm, but not nuclei of bovine MDSCs. • TCEA3 levels increased as myotube differentiation increased. • TCEA3 affected myotube fusion, myotube counts, and MYOG and MYH3 levels.

The Future of Satellite Communications Technology.

Science.gov (United States)

Nowland, Wayne

1985-01-01

Discusses technical advances in satellite technology since the 1960s, and the International Telecommunications Satellite Organization's role in these developments; describes how AUSSAT, Australia's domestic satellite system, exemplifies the latest developments in satellite technology; and reviews satellite system features, possible future…

Do asteroids have satellites

International Nuclear Information System (INIS)

Weidenschilling, S.J.; Paolicchi, P.; Zappala, V.

1989-01-01

A substantial body of indirect evidence suggests that some asteroids have satelities, although none has been detected unambiguously. Collisions between asteroids provide physically plausible mechanisms for the production of binaries, but these operate with low probability; only a small minority of asteroids are likely to have satellites. The abundance of binary asteroids can constrain the collisional history of the entire belt population. The allowed angular momentum of binaries and their rate of tidal evolution limit separations to no more than a few tens of the primary's radii. Their expected properties are consistent with failure to detect them by current imaging techniques

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

Luteal phase of the menstrual cycle increases sweating rate during exercise

Directory of Open Access Journals (Sweden)

Garcia A.M.C.

2006-01-01

Full Text Available The present study evaluated whether the luteal phase elevation of body temperature would be offset during exercise by increased sweating, when women are normally hydrated. Eleven women performed 60 min of cycling exercise at 60% of their maximal work load at 32ºC and 80% relative air humidity. Each subject participated in two identical experimental sessions: one during the follicular phase (between days 5 and 8 and the other during the luteal phase (between days 22 and 25. Women with serum progesterone >3 ng/mL, in the luteal phase were classified as group 1 (N = 4, whereas the others were classified as group 2 (N = 7. Post-exercise urine volume (213 ± 80 vs 309 ± 113 mL and specific urine gravity (1.008 ± 0.003 vs 1.006 ± 0.002 changed (P < 0.05 during the luteal phase compared to the follicular phase in group 1. No menstrual cycle dependence was observed for these parameters in group 2. Sweat rate was higher (P < 0.05 in the luteal (3.10 ± 0.81 g m-2 min-1 than in the follicular phase (2.80 ± 0.64 g m-2 min-1 only in group 1. During exercise, no differences related to menstrual cycle phases were seen in rectal temperature, heart rate, rate of perceived exertion, mean skin temperature, and pre- and post-exercise body weight. Women exercising in a warm and humid environment with water intake seem to be able to adapt to the luteal phase increase of basal body temperature through reduced urinary volume and increased sweating rate.

Comparison of different "along the track" high resolution satellite stereo-pair for DSM extraction

Science.gov (United States)

Nikolakopoulos, Konstantinos G.

2013-10-01

The possibility to create DEM from stereo pairs is based on the Pythagoras theorem and on the principles of photogrammetry that are applied to aerial photographs stereo pairs for the last seventy years. The application of these principles to digital satellite stereo data was inherent in the first satellite missions. During the last decades the satellite stereo-pairs were acquired across the track in different days (SPOT, ERS etc.). More recently the same-date along the track stereo-data acquisition seems to prevail (Terra ASTER, SPOT5 HRS, Cartosat, ALOS Prism) as it reduces the radiometric image variations (refractive effects, sun illumination, temporal changes) and thus increases the correlation success rate in any image matching.Two of the newest satellite sensors with stereo collection capability is Cartosat and ALOS Prism. Both of them acquire stereopairs along the track with a 2,5m spatial resolution covering areas of 30X30km. In this study we compare two different satellite stereo-pair collected along the track for DSM creation. The first one is created from a Cartosat stereopair and the second one from an ALOS PRISM triplet. The area of study is situated in Chalkidiki Peninsula, Greece. Both DEMs were created using the same ground control points collected with a Differential GPS. After a first control for random or systematic errors a statistical analysis was done. Points of certified elevation have been used to estimate the accuracy of these two DSMs. The elevation difference between the different DEMs was calculated. 2D RMSE, correlation and the percentile value were also computed and the results are presented.

Effect of sun and planet-bound dark matter on planet and satellite dynamics in the solar system

International Nuclear Information System (INIS)

Iorio, L.

2010-01-01

We apply our recent results on orbital dynamics around a mass-varying central body to the phenomenon of accretion of Dark Matter-assumed not self-annihilating-on the Sun and the major bodies of the solar system due to its motion throughout the Milky Way halo. We inspect its consequences on the orbits of the planets and their satellites over timescales of the order of the age of the solar system. It turns out that a solar Dark Matter accretion rate of ≈ 10 −12 yr −1 , inferred from the upper limit ΔM/M = 0.02−0.05 on the Sun's Dark Matter content, assumed somehow accumulated during last 4.5 Gyr, would have displaced the planets faraway by about 10 −2 −10 1 au 4.5 Gyr ago. Another consequence is that the semimajor axis of the Earth's orbit, approximately equal to the Astronomical Unit, would undergo a secular increase of 0.02-0.05 m yr −1 , in agreement with the latest observational determinations of the Astronomical Unit secular increase of 0.07±0.02 m yr −1 and 0.05 m yr −1 . By assuming that the Sun will continue to accrete Dark Matter in the next billions year at the same rate as putatively done in the past, the orbits of its planets will shrink by about 10 −1 −10 1 au ( ≈ 0.2−0.5 au for the Earth), with consequences for their fate, especially of the inner planets. On the other hand, lunar and planetary ephemerides set upper bounds on the secular variation of the Sun's gravitational parameter GM which are one one order of magnitude smaller than ≈ 10 −12 yr −1 . Dark Matter accretion on planets has, instead, less relevant consequences for their satellites. Indeed, 4.5 Gyr ago their orbits would have been just 10 −2 −10 1 km wider than now. Dark Matter accretion is not able to explain the observed accelerations of the orbits of some of the Galilean satellites of Jupiter, the secular decrease of the semimajor axis of the Earth's artificial satellite LAGEOS and the secular increase of the Moon's orbit eccentricity

Assessment of satellite-based precipitation estimates over Paraguay

Science.gov (United States)

Oreggioni Weiberlen, Fiorella; Báez Benítez, Julián

2018-04-01

Satellite-based precipitation estimates represent a potential alternative source of input data in a plethora of meteorological and hydrological applications, especially in regions characterized by a low density of rain gauge stations. Paraguay provides a good example of a case where the use of satellite-based precipitation could be advantageous. This study aims to evaluate the version 7 of the Tropical Rainfall Measurement Mission Multi-Satellite Precipitation Analysis (TMPA V7; 3B42 V7) and the version 1.0 of the purely satellite-based product of the Climate Prediction Center Morphing Technique (CMORPH RAW) through their comparison with daily in situ precipitation measurements from 1998 to 2012 over Paraguay. The statistical assessment is conducted with several commonly used indexes. Specifically, to evaluate the accuracy of daily precipitation amounts, mean error (ME), root mean square error (RMSE), BIAS, and coefficient of determination (R 2) are used, and to analyze the capability to correctly detect different precipitation intensities, false alarm ratio (FAR), frequency bias index (FBI), and probability of detection (POD) are applied to various rainfall rates (0, 0.1, 0.5, 1, 2, 5, 10, 20, 40, 60, and 80 mm/day). Results indicate that TMPA V7 has a better performance than CMORPH RAW over Paraguay. TMPA V7 has higher accuracy in the estimation of daily rainfall volumes and greater precision in the detection of wet days (> 0 mm/day). However, both satellite products show a lower ability to appropriately detect high intensity precipitation events.

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

Rate of tree carbon accumulation increases continuously with tree size.

Science.gov (United States)

Stephenson, N L; Das, A J; Condit, R; Russo, S E; Baker, P J; Beckman, N G; Coomes, D A; Lines, E R; Morris, W K; Rüger, N; Alvarez, E; Blundo, C; Bunyavejchewin, S; Chuyong, G; Davies, S J; Duque, A; Ewango, C N; Flores, O; Franklin, J F; Grau, H R; Hao, Z; Harmon, M E; Hubbell, S P; Kenfack, D; Lin, Y; Makana, J-R; Malizia, A; Malizia, L R; Pabst, R J; Pongpattananurak, N; Su, S-H; Sun, I-F; Tan, S; Thomas, D; van Mantgem, P J; Wang, X; Wiser, S K; Zavala, M A

2014-03-06

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

Rate of tree carbon accumulation increases continuously with tree size

Science.gov (United States)

Stephenson, N.L.; Das, A.J.; Condit, R.; Russo, S.E.; Baker, P.J.; Beckman, N.G.; Coomes, D.A.; Lines, E.R.; Morris, W.K.; Rüger, N.; Álvarez, E.; Blundo, C.; Bunyavejchewin, S.; Chuyong, G.; Davies, S.J.; Duque, Á.; Ewango, C.N.; Flores, O.; Franklin, J.F.; Grau, H.R.; Hao, Z.; Harmon, M.E.; Hubbell, S.P.; Kenfack, D.; Lin, Y.; Makana, J.-R.; Malizia, A.; Malizia, L.R.; Pabst, R.J.; Pongpattananurak, N.; Su, S.-H.; Sun, I-F.; Tan, S.; Thomas, D.; van Mantgem, P.J.; Wang, X.; Wiser, S.K.; Zavala, M.A.

2014-01-01

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage - increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to understand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

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

Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

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.

Population-based geographic access to parent and satellite National Cancer Institute Cancer Center Facilities.

Science.gov (United States)

Onega, Tracy; Alford-Teaster, Jennifer; Wang, Fahui

2017-09-01

Satellite facilities of National Cancer Institute (NCI) cancer centers have expanded their regional footprints. This study characterized geographic access to parent and satellite NCI cancer center facilities nationally overall and by sociodemographics. Parent and satellite NCI cancer center facilities, which were geocoded in ArcGIS, were ascertained. Travel times from every census tract in the continental United States and Hawaii to the nearest parent and satellite facilities were calculated. Census-based population attributes were used to characterize measures of geographic access for sociodemographic groups. From the 62 NCI cancer centers providing clinical care in 2014, 76 unique parent locations and 211 satellite locations were mapped. The overall proportion of the population within 60 minutes of a facility was 22% for parent facilities and 32.7% for satellite facilities. When satellites were included for potential access, the proportion of some racial groups for which a satellite was the closest NCI cancer center facility increased notably (Native Americans, 22.6% with parent facilities and 39.7% with satellite facilities; whites, 34.8% with parent facilities and 50.3% with satellite facilities; and Asians, 40.0% with parent facilities and 54.0% with satellite facilities), with less marked increases for Hispanic and black populations. Rural populations of all categories had dramatically low proportions living within 60 minutes of an NCI cancer center facility of any type (1.0%-6.6%). Approximately 14% of the population (n = 43,033,310) lived more than 180 minutes from a parent or satellite facility, and most of these individuals were Native Americans and/or rural residents (37% of Native Americans and 41.7% of isolated rural residents). Racial/ethnic and rural populations showed markedly improved geographic access to NCI cancer center care when satellite facilities were included. Cancer 2017;123:3305-11. © 2017 American Cancer Society. © 2017 American

Increased rate of treatment with antidepressants in patients with multiple sclerosis

DEFF Research Database (Denmark)

Kessing, Lars Vedel; Harhoff, Mette; Andersen, Per Kragh

2008-01-01

The prevalence of depression and anxiety is increased in patients with multiple sclerosis, but it has not been investigated whether these conditions are treated in clinical practice. The objective of this study was to investigate whether the rate of treatment with antidepressants is increased...... in patients with multiple sclerosis compared with patients with other chronic illnesses and compared with the general population. By linkage of nationwide case registers, all patients were identified, who had received a main diagnosis of multiple sclerosis or osteoarthritis at first admission or during...... outpatient contact in the period 1995-2000 in Denmark. Rates of subsequent purchase of antidepressants for these patients were calculated. In total, 417 patients with a main diagnosis of multiple sclerosis and 12 127 patients with a main diagnosis of osteoarthritis, at first discharge from hospital...

Cosmic rays and other space weather effects influenced on satellite operation, technologies, biosphere and people health

Science.gov (United States)

Lev, Dorman

2016-07-01

Satellite anomalies (or malfunctions), including total distortion of electronics and loose of some satellites cost for Insurance Companies billions dollars per year. During especially active periods the probability of big satellite anomalies and their loosing increased very much. Now, when a great number of civil and military satellites are continuously worked for our practice life, the problem of satellite anomalies became very important. Many years ago about half of satellite anomalies were caused by technical reasons (for example, for Russian satellites Kosmos), but with time with increasing of production quality, this part became smaller and smaller. The other part, which now is dominated, caused by different space weather effects (energetic particles of CR and generated/trapped in the magnetosphere, and so on). We consider only satellite anomalies not caused by technical reasons: the total number of such anomalies about 6000 events, and separately for high and low altitude orbit satellites (5000 and about 800 events, correspondingly for high and low altitude satellites). No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and solar proton event onsets for high (>1500 km) and low (railway operation (possible, through induction currents), catastrophes in long-distance electric power lines and transformators, and in other ground technologies.

Satellite Imagery Analysis for Automated Global Food Security Forecasting

Science.gov (United States)

Moody, D.; Brumby, S. P.; Chartrand, R.; Keisler, R.; Mathis, M.; Beneke, C. M.; Nicholaeff, D.; Skillman, S.; Warren, M. S.; Poehnelt, J.

2017-12-01

The recent computing performance revolution has driven improvements in sensor, communication, and storage technology. Multi-decadal remote sensing datasets at the petabyte scale are now available in commercial clouds, with new satellite constellations generating petabytes/year of daily high-resolution global coverage imagery. Cloud computing and storage, combined with recent advances in machine learning, are enabling understanding of the world at a scale and at a level of detail never before feasible. We present results from an ongoing effort to develop satellite imagery analysis tools that aggregate temporal, spatial, and spectral information and that can scale with the high-rate and dimensionality of imagery being collected. We focus on the problem of monitoring food crop productivity across the Middle East and North Africa, and show how an analysis-ready, multi-sensor data platform enables quick prototyping of satellite imagery analysis algorithms, from land use/land cover classification and natural resource mapping, to yearly and monthly vegetative health change trends at the structural field level.

Satellite switching concepts for European business services in the nineties

Science.gov (United States)

Lombard, D.; Rouffet, D.

A first generation of business communication satellites are now operational or to be launched. Increased demands for communication satellite facilities will develop, if special services, such as videoconferencing, can be provided at a reasonable cost. For such developments, it will be necessary to define a second generation of business communication satellites. The present investigation evaluates briefly the size of the expected European market for 1995. A study is conducted of the payload structure for the required satellite system, and aspects related to link budgets and power consumption are explored. It is found that system dimensioning is determined by the up-link and by technology. Critical factors are related to the output and input multiplexors for the link budget, the switching matrix, and implications for the mass budget. The best trade-off between technological, mass, and link budget limitations is achieved in connection with the employment of a hinged antennas satellite, using an intermediate number of spot beams and associated earth stations of reasonable size.

Analysis on Space Environment from the Anomalies of Geosynchronous Satellites

Directory of Open Access Journals (Sweden)

Jaejin Lee

2009-12-01

Full Text Available While it is well known that space environment can produce spacecraft anomaly, defining space environment effects for each anomalies is difficult. This is caused by the fact that spacecraft anomaly shows various symptoms and reproducing it is impossible. In this study, we try to find the conditions of when spacecraft failures happen more frequently and give satellite operators useful information. Especially, our study focuses on the geosynchronous satellites which cost is high and required high reliability. We used satellite anomaly data given by Satellite News Digest which is internet newspaper providing space industry news. In our analysis, 88 anomaly cases occurred from 1997 to 2008 shows bad corelation with Kp index. Satellite malfunctions were likely to happen in spring and fall and in local time from midnight to dawn. In addition, we found the probability of anomaly increase when high energy electron flux is high. This is more clearly appeared in solar minimum than maximum period.

Increased resting heart rate following radiofrequency catheter ablation for atrial fibrillation

DEFF Research Database (Denmark)

Nilsson, Brian; Chen, Xu; Pehrson, Steen

2005-01-01

the procedure. RESULTS: Following PV isolation, the mean HR significantly increased from 58 +/- 10 bpm at baseline to 67 +/- 12 bpm at one month, 71 +/- 13 bpm at three months, 69 +/- 12 bpm at six months, 69 +/- 13 at nine months, and 70 +/- 13 at 12 months follow-up. The ablation success significantly...... correlated with the increase in HR at one month follow-up. In three patients the mean HR increased > 25 bpm resulting in symptoms necessitating therapy with rate-controlling drugs. CONCLUSION: PV isolation in patients with AF may result in increased HR, which positively correlated with the ablation success...

Visual attention based detection of signs of anthropogenic activities in satellite imagery

Energy Technology Data Exchange (ETDEWEB)

Skurikhin, Alexei N [Los Alamos National Laboratory

2010-10-13

With increasing deployment of satellite imaging systems, only a small fraction of collected data can be subject to expert scrutiny. We present and evaluate a two-tier approach to broad area search for signs of anthropogenic activities in high-resolution commercial satellite imagery. The method filters image information using semantically oriented interest points by combining Harris corner detection and spatial pyramid matching. The idea is that anthropogenic structures, such as rooftop outlines, fence corners, road junctions, are locally arranged in specific angular relations to each other. They are often oriented at approximately right angles to each other (which is known as rectilinearity relation). Detecting the rectilinearity provides an opportunity to highlight regions most likely to contain anthropogenic activity. This is followed by supervised classification of regions surrounding the detected corner points as man-made vs. natural scenes. We consider, in particular, a search for anthropogenic activities in uncluttered areas. In this paper, we proposed and evaluated a two-tier approach to broad area search for signs of anthropogenic activities. Results from experiments on high-resolution ({approx}0.6m) commercial satellite image data showed the potential applicability of this approach and its ability of achieving both high precision and recall rates. The main advantage of combining corner-based cueing with general object recognition is that the incorporation of domain specific knowledge even in its more general form, such as presence of comers, provides a useful cue to narrow the focus of search for signs of anthropogenic activities. Combination of comer based cueing with spatial pyramid matching addressed the issue of comer categorization. An important practical issue for further research is optimizing the balance between false positive and false negative rates. While the results presented in the paper are encouraging, the problem of an automated broad area

Gamma-ray dose rate increase at rainfall events and their air-mass origins

International Nuclear Information System (INIS)

Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

2007-01-01

The environmental γ-ray dose rate and precipitation rates were measured at our institute, in Rokkasho, Aomori, Japan. We analyzed 425 rainfall events in which the precipitation rate was over 0.5 mm from April through November during the years 2003 to 2005. Backward trajectories for 5 d starting from 1000 m above Rokkasho at the time of the maximum dose rate in a rainfall event, were calculated by using the HYSPLIT model of the NOAA Air Resources Laboratory. The trajectories for 5 d were classified by visual inspection according to the passage areas; Pacific Ocean, Asian Continent and Japan Islands. The increase of cumulative environmental γ-ray dose during a rainfall event was plotted against the precipitation in the event, and their relationship was separately examined according to the air-mass passage area, i.e. origin of the air-mass. Our results showed that the origin of air-mass was an important factor affecting the increase of environmental γ-ray dose rate by rainfall. (author)

Unresolved dielectronic satellites of the resonance line of heliumlike iron (Fe XXV)

International Nuclear Information System (INIS)

Bitter, M.; von Goeler, S.; Hill, K.W.; Horton, R.; Johnson, D.; Roney, W.; Sauthoff, N.; Silver, E.; Stodiek, W.

1981-02-01

(1s 2 nl - 1s2pnl, n greater than or equal to 3) dielectronic satellites of the resonance line of Fe XXV at 1.85 A have been observed from PLT (Princeton Large Torus) tokamak discharges and are used for a detailed comparison with theory. The necessary corrections for Doppler broadening measurements are discussed, and accurate satellite to resonance line ratios allowing for a determination of the total dielectronic recombination rate of Fe XXV are derived

A Survey of Congestion Control Techniques and Data Link Protocols in Satellite Networks

OpenAIRE

Fahmy, Sonia; Jain, Raj; Lu, Fang; Kalyanaraman, Shivkumar

1998-01-01

Satellite communication systems are the means of realizing a global broadband integrated services digital network. Due to the statistical nature of the integrated services traffic, the resulting rate fluctuations and burstiness render congestion control a complicated, yet indispensable function. The long propagation delay of the earth-satellite link further imposes severe demands and constraints on the congestion control schemes, as well as the media access control techniques and retransmissi...

Japanese Global Precipitation Measurement (GPM) mission status and application of satellite-based global rainfall map

Science.gov (United States)

Kachi, Misako; Shimizu, Shuji; Kubota, Takuji; Yoshida, Naofumi; Oki, Riko; Kojima, Masahiro; Iguchi, Toshio; Nakamura, Kenji

2010-05-01

As accuracy of satellite precipitation estimates improves and observation frequency increases, application of those data to societal benefit areas, such as weather forecasts and flood predictions, is expected, in addition to research of precipitation climatology to analyze precipitation systems. There is, however, limitation on single satellite observation in coverage and frequency. Currently, the Global Precipitation Measurement (GPM) mission is scheduled under international collaboration to fulfill various user requirements that cannot be achieved by the single satellite, like the Tropical Rainfall Measurement Mission (TRMM). The GPM mission is an international mission to achieve high-accurate and high-frequent rainfall observation over a global area. GPM is composed of a TRMM-like non-sun-synchronous orbit satellite (GPM core satellite) and constellation of satellites carrying microwave radiometer instruments. The GPM core satellite carries the Dual-frequency Precipitation Radar (DPR), which is being developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT), and microwave radiometer provided by the National Aeronautics and Space Administration (NASA). Development of DPR instrument is in good progress for scheduled launch in 2013, and DPR Critical Design Review has completed in July - September 2009. Constellation satellites, which carry a microwave imager and/or sounder, are planned to be launched around 2013 by each partner agency for its own purpose, and will contribute to extending coverage and increasing frequency. JAXA's future mission, the Global Change Observation Mission (GCOM) - Water (GCOM-W) satellite will be one of constellation satellites. The first generation of GCOM-W satellite is scheduled to be launched in 2011, and it carries the Advanced Microwave Scanning Radiometer 2 (AMSR2), which is being developed based on the experience of the AMSR-E on EOS Aqua satellite

An examination of black/white differences in the rate of age-related mortality increase

Directory of Open Access Journals (Sweden)

Andrew Fenelon

2013-09-01

Full Text Available BACKGROUND The rate of mortality increase with age among adults is typically used as a measure of the rate of functional decline associated with aging or senescence. While black and white populations differ in the level of mortality, mortality also rises less rapidly with age for blacks than for whites, leading to the well-known black/white mortality "crossover". OBJECTIVE This paper investigates black/white differences in the rate of mortality increase with age for major causes of death in order to examine the factors responsible for the black/white crossover. METHODS The analysis considers two explanations for the crossover: selective survival and age misreporting. Mortality is modeled using a Gompertz model for 11 causes of death from ages 50-84 among blacks and whites by sex. RESULTS Mortality increases more rapidly with age for whites than for blacks for nearly all causes of death considered. The all-cause mortality rate of mortality increase is nearly two percentage points higher for whites. The analysis finds evidence for both selective survival and age misreporting, although age misreporting is a more prominent explanation among women. CONCLUSIONS The black/white mortality crossover reflects large differences in the rate of age-related mortality increase. Instead of reflecting the impact of specific causes of death, this pattern exists across many disparate disease conditions, indicating the need for a broad explanation.

GALAXIES IN X-RAY GROUPS. III. SATELLITE COLOR AND MORPHOLOGY TRANSFORMATIONS

Energy Technology Data Exchange (ETDEWEB)

George, Matthew R.; Ma, Chung-Pei [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Bundy, Kevin; Leauthaud, Alexie; Vulcani, Benedetta [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, University of Tokyo, Kashiwa 277-8583 (Japan); Tinker, Jeremy [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Finoguenov, Alexis, E-mail: mgeorge@astro.berkeley.edu [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland)

2013-06-20

While the star formation rates and morphologies of galaxies have long been known to correlate with their local environment, the process by which these correlations are generated is not well understood. Galaxy groups are thought to play an important role in shaping the physical properties of galaxies before entering massive clusters at low redshift, and transformations of satellite galaxies likely dominate the buildup of local environmental correlations. To illuminate the physical processes that shape galaxy evolution in dense environments, we study a sample of 116 X-ray selected galaxy groups at z = 0.2-1 with halo masses of 10{sup 13}-10{sup 14} M{sub Sun} and centroids determined with weak lensing. We analyze morphologies based on Hubble Space Telescope imaging and colors determined from 31 photometric bands for a stellar mass-limited population of 923 satellite galaxies and a comparison sample of 16,644 field galaxies. Controlling for variations in stellar mass across environments, we find significant trends in the colors and morphologies of satellite galaxies with group-centric distance and across cosmic time. Specifically at low stellar mass (log (M{sub *}/M{sub Sun }) = 9.8-10.3), the fraction of disk-dominated star-forming galaxies declines from >50% among field galaxies to <20% among satellites near the centers of groups. This decline is accompanied by a rise in quenched galaxies with intermediate bulge+disk morphologies, and only a weak increase in red bulge-dominated systems. These results show that both color and morphology are influenced by a galaxy's location within a group halo. We suggest that strangulation and disk fading alone are insufficient to explain the observed morphological dependence on environment, and that galaxy mergers or close tidal encounters must play a role in building up the population of quenched galaxies with bulges seen in dense environments at low redshift.

GALAXIES IN X-RAY GROUPS. III. SATELLITE COLOR AND MORPHOLOGY TRANSFORMATIONS

International Nuclear Information System (INIS)

George, Matthew R.; Ma, Chung-Pei; Bundy, Kevin; Leauthaud, Alexie; Vulcani, Benedetta; Tinker, Jeremy; Wechsler, Risa H.; Finoguenov, Alexis

2013-01-01

While the star formation rates and morphologies of galaxies have long been known to correlate with their local environment, the process by which these correlations are generated is not well understood. Galaxy groups are thought to play an important role in shaping the physical properties of galaxies before entering massive clusters at low redshift, and transformations of satellite galaxies likely dominate the buildup of local environmental correlations. To illuminate the physical processes that shape galaxy evolution in dense environments, we study a sample of 116 X-ray selected galaxy groups at z = 0.2-1 with halo masses of 10 13 -10 14 M ☉ and centroids determined with weak lensing. We analyze morphologies based on Hubble Space Telescope imaging and colors determined from 31 photometric bands for a stellar mass-limited population of 923 satellite galaxies and a comparison sample of 16,644 field galaxies. Controlling for variations in stellar mass across environments, we find significant trends in the colors and morphologies of satellite galaxies with group-centric distance and across cosmic time. Specifically at low stellar mass (log (M * /M ☉ ) = 9.8-10.3), the fraction of disk-dominated star-forming galaxies declines from >50% among field galaxies to <20% among satellites near the centers of groups. This decline is accompanied by a rise in quenched galaxies with intermediate bulge+disk morphologies, and only a weak increase in red bulge-dominated systems. These results show that both color and morphology are influenced by a galaxy's location within a group halo. We suggest that strangulation and disk fading alone are insufficient to explain the observed morphological dependence on environment, and that galaxy mergers or close tidal encounters must play a role in building up the population of quenched galaxies with bulges seen in dense environments at low redshift.

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

Science.gov (United States)

Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

2000-01-01

Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

Ballistic Aspects of Feasibility for Prospective Satellite Navigation Technologies

Directory of Open Access Journals (Sweden)

L. N. Lysenko

2015-01-01

Full Text Available When modeling the operating processes of ballistics and navigation support it is expedient to make decomposition of the general problem of coordinate-time and navigation support into the typical options of its engineering implementation.As the satellite navigation technologies the paper considers inter-satellite measurement and autonomous navigation mode of differential correction. It also assesses the possibility of their application to improve the accuracy of navigation determinations.Technologies using inter-satellite measurement tools such as GLONASS / GPS equipment, equipment of inter-satellite radio link, astro-optical space based devices are an independent class of navigation technologies.However, each of these options has both advantages and disadvantages that affect the eva luation of the appropriateness and feasibility of their use.The paper separately considers the problem of increasing survivability of space systems and conservation of ground control complex due to introduction of requirements to ensure the independent functioning of spacecraft and application of technologies of ballistics and navigation support, supposing to involve minimum means of automated ground control complex for these purposes.Currently, there is a completely developed theory of autonomous navigation based on astronomical positional gauges, which are used as onboard optical sensors of orientation and stabilization systems.To date, the differential navigation mode is, virtually, the only approach that can allow the olution of tasks in terms of increased accuracy, but with some restrictions.The implementation of differential mode of treatment is carried out through the creation of differential subsystems of the satellite navigation systems. These subsystems are usually divided into wide-range, regional and local ones.Analysis of ballistic aspects to implement discussed navigation technologies allowed us to identify constraints for improving accuracy to define

Estimating detection rates for the LIGO-Virgo search for gravitational-wave burst counterparts to gamma-ray bursts using inferred local GRB rates

International Nuclear Information System (INIS)

Leonor, I; Frey, R; Sutton, P J; Jones, G; Marka, S; Marka, Z

2009-01-01

One of the ongoing searches performed using the LIGO-Virgo network of gravitational-wave interferometers is the search for gravitational-wave burst (GWB) counterparts to gamma-ray bursts (GRBs). This type of analysis makes use of GRB time and position information from gamma-ray satellite detectors to trigger the GWB search, and the GWB detection rates possible for such an analysis thus strongly depend on the GRB detection efficiencies of the satellite detectors. Using local GRB rate densities inferred from observations which are found in the science literature, we calculate estimates of the GWB detection rates for different configurations of the LIGO-Virgo network for this type of analysis.

In situ statistical observations of EMIC waves by Arase satellite

Science.gov (United States)

Nomura, R.; Matsuoka, A.; Teramoto, M.; Nose, M.; Yoshizumi, M.; Fujimoto, A.; Shinohara, M.; Tanaka, Y.

2017-12-01

We present in situ statistical survey of electromagnetic ion cyclotron (EMIC) waves observed by Arase satellite from 3 March to 16 July 2017. We identified 64 events using the fluxgate magnetometer (MGF) on the satellite. The EMIC wave is the key phenomena to understand the loss dynamics of MeV-energy electrons in the radiation belt. We will show the radial and latitudinal dependence of the wave occurance rate and the wave parameters (frequency band, coherence, polarization, and ellipticity). Especially the EMIC waves observed at localized weak background magnetic field will be discussed for the wave excitation mechanism in the deep inner magnetosphere.

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...

The Eccentric Satellites Problem: Comparing Milky Way Satellite Orbital Properties to Simulation Results

Science.gov (United States)

Haji, Umran; Pryor, Carlton; Applebaum, Elaad; Brooks, Alyson

2018-01-01

We compare the orbital properties of the satellite galaxies of the Milky Way to those of satellites found in simulated Milky Way-like systems as a means of testing cosmological simulations of galaxy formation. The particular problem that we are investigating is a discrepancy in the distribution of orbital eccentricities. Previous studies of Milky Way-mass systems analyzed in a semi-analytic ΛCDM cosmological model have found that the satellites tend to have significantly larger fractions of their kinetic energy invested in radial motion with respect to their central galaxy than do the real-world Milky Way satellites. We analyze several high-resolution ("zoom-in") hydrodynamical simulations of Milky Way-mass galaxies and their associated satellite systems to investigate why previous works found Milky Way-like systems to be rare. We find a possible relationship between a quiescent galactic assembly history and a distribution of satellite kinematics resembling that of the Milky Way. This project has been supported by funding from National Science Foundation grant PHY-1560077.

Data Collection Satellite Application in Precision Agriculture

Science.gov (United States)

Durào, O.

2002-01-01

Agricultural Instrumentation Research Center, Brazilian Agricultural Research Corporation; Space Programs Brazil launched in 1993 its first satellite partially built and entirely designed, integrated, tested and operated in the country. It was the SCD-1 satellite, a small (115 kg. and an octagonal prism with 80 cm. height and an external diameter of 100 cm.) with a payload transponder that receives data from ground platforms spread all over the country (including its sea shore). These data are then retransmitted to a receiving station at every satellite pass. Data collected and received are processed at Data Collection Mission Center for distribution via internet at most 30 min after the satellite pass. The ground platforms are called PCD's and differ in the parameters measured according to its purpose and location. Thus, they are able to measure temperature, rain level, wind direction, solar radiation, carbon monoxide as well as many others, beyond its own location. SCD- 1 had a nominal designed life of one year, but is still functioning. It is a LEO satellite with inclination of 25°. In 1998, the country launched SCD-2, with the same purpose, but in phase with SCD-1 . Other differences were a higher index of Brazilian made components and an active attitude control subsystem for the spin rate provided by the magnetic torque coils (these in accordance with a development strategy previously planned). In 1999 the country launched in cooperation with China a remote sensing satellite (mass of 1.4 ton.) called CBERS-1. This satellite is sun synchronous (98° inclination) and also carries a transponder for data collection/transmission as a secondary payload. Thus, the country has now three satellites with data collection/transmission capabilities, two in low inclination phased orbits and one in polar orbit, providing a nice coverage both geographical and temporal not only to its territory but also to other regions of the world.. At first there were not too many PCD

Prolonged operative time increases infection rate in tibial plateau fractures.

Science.gov (United States)

Colman, Matthew; Wright, Adam; Gruen, Gary; Siska, Peter; Pape, Hans-Christoph; Tarkin, Ivan

2013-02-01

Fractures of the tibial plateau present a treatment challenge and are susceptible to both prolonged operative times and high postoperative infection rates. For those fractures treated with open plating, we sought to identify the relationship between surgical site infection and prolonged operative time as well as to identify other surgical risk factors. We performed a retrospective controlled analysis of 309 consecutive unicondylar and bicondylar tibial plateau fractures treated with open plate osteosynthesis at our institution's level I trauma centre during a recent 5-year period. We recorded operative times, injury characteristics, surgical treatment, and need for operative debridement due to infection. Operative times of infected cases were compared to uncomplicated surgical cases. Multivariable logistic regression analysis was performed to identify independent risk factors for postoperative infection. Mean operative time in the infection group was 2.8h vs. 2.2h in the non-infected group (p=0.005). 15 fractures (4.9%) underwent four compartment fasciotomies as part of their treatment, with a significantly higher infection rate than those not undergoing fasciotomy (26.7% vs. 6.8%, p=0.01). Open fracture grade was also significantly related to infection rate (closed fractures: 5.3%, grade 1: 14.3%, grade 2: 40%, grade 3: 50%, pinfection rates (13.9% vs. 8.7%, p=0.36). Multivariable logistic regression analysis of the entire study group identified longer operative times (OR 1.78, p=0.013) and open fractures (OR 7.02, psite infection. Operative times approaching 3h and open fractures are related to an increased overall risk for surgical site infection after open plating of the tibial plateau. Dual incision approaches with bicolumnar plating do not appear to expose the patient to increased risk compared to single incision approaches. Copyright © 2012 Elsevier Ltd. All rights reserved.

Increased Ratio of Electron Transport to Net Assimilation Rate Supports Elevated Isoprenoid Emission Rate in Eucalypts under Drought1[W][OPEN

Science.gov (United States)

Dani, Kaidala Ganesha Srikanta; Jamie, Ian McLeod; Prentice, Iain Colin; Atwell, Brian James

2014-01-01

Plants undergoing heat and low-CO2 stresses emit large amounts of volatile isoprenoids compared with those in stress-free conditions. One hypothesis posits that the balance between reducing power availability and its use in carbon assimilation determines constitutive isoprenoid emission rates in plants and potentially even their maximum emission capacity under brief periods of stress. To test this, we used abiotic stresses to manipulate the availability of reducing power. Specifically, we examined the effects of mild to severe drought on photosynthetic electron transport rate (ETR) and net carbon assimilation rate (NAR) and the relationship between estimated energy pools and constitutive volatile isoprenoid emission rates in two species of eucalypts: Eucalyptus occidentalis (drought tolerant) and Eucalyptus camaldulensis (drought sensitive). Isoprenoid emission rates were insensitive to mild drought, and the rates increased when the decline in NAR reached a certain species-specific threshold. ETR was sustained under drought and the ETR-NAR ratio increased, driving constitutive isoprenoid emission until severe drought caused carbon limitation of the methylerythritol phosphate pathway. The estimated residual reducing power unused for carbon assimilation, based on the energetic status model, significantly correlated with constitutive isoprenoid emission rates across gradients of drought (r2 > 0.8) and photorespiratory stress (r2 > 0.9). Carbon availability could critically limit emission rates under severe drought and photorespiratory stresses. Under most instances of moderate abiotic stress levels, increased isoprenoid emission rates compete with photorespiration for the residual reducing power not invested in carbon assimilation. A similar mechanism also explains the individual positive effects of low-CO2, heat, and drought stresses on isoprenoid emission. PMID:25139160

Partnership via Satellite.

Science.gov (United States)

Powell, Marie Clare

1980-01-01

Segments of the 1980 National Catholic Educational Association (NCEA) conference were to be telecast nationally by satellite. The author briefly explains the satellite transmission process and advises Catholic educators on how to pick up the broadcast through their local cable television system. (SJL)

Ranging error analysis of single photon satellite laser altimetry under different terrain conditions

Science.gov (United States)

Huang, Jiapeng; Li, Guoyuan; Gao, Xiaoming; Wang, Jianmin; Fan, Wenfeng; Zhou, Shihong

2018-02-01

Single photon satellite laser altimeter is based on Geiger model, which has the characteristics of small spot, high repetition rate etc. In this paper, for the slope terrain, the distance of error's formula and numerical calculation are carried out. Monte Carlo method is used to simulate the experiment of different terrain measurements. The experimental results show that ranging accuracy is not affected by the spot size under the condition of the flat terrain, But the inclined terrain can influence the ranging error dramatically, when the satellite pointing angle is 0.001° and the terrain slope is about 12°, the ranging error can reach to 0.5m. While the accuracy can't meet the requirement when the slope is more than 70°. Monte Carlo simulation results show that single photon laser altimeter satellite with high repetition rate can improve the ranging accuracy under the condition of complex terrain. In order to ensure repeated observation of the same point for 25 times, according to the parameters of ICESat-2, we deduce the quantitative relation between the footprint size, footprint, and the frequency repetition. The related conclusions can provide reference for the design and demonstration of the domestic single photon laser altimetry satellite.

Arctic Climate Variability and Trends from Satellite Observations

Directory of Open Access Journals (Sweden)

Xuanji Wang

2012-01-01

Full Text Available Arctic climate has been changing rapidly since the 1980s. This work shows distinctly different patterns of change in winter, spring, and summer for cloud fraction and surface temperature. Satellite observations over 1982–2004 have shown that the Arctic has warmed up and become cloudier in spring and summer, but cooled down and become less cloudy in winter. The annual mean surface temperature has increased at a rate of 0.34°C per decade. The decadal rates of cloud fraction trends are −3.4%, 2.3%, and 0.5% in winter, spring, and summer, respectively. Correspondingly, annually averaged surface albedo has decreased at a decadal rate of −3.2%. On the annual average, the trend of cloud forcing at the surface is −2.11 W/m2 per decade, indicating a damping effect on the surface warming by clouds. The decreasing sea ice albedo and surface warming tend to modulate cloud radiative cooling effect in spring and summer. Arctic sea ice has also declined substantially with decadal rates of −8%, −5%, and −15% in sea ice extent, thickness, and volume, respectively. Significant correlations between surface temperature anomalies and climate indices, especially the Arctic Oscillation (AO index, exist over some areas, implying linkages between global climate change and Arctic climate change.

NOAA budget would boost satellite funding but cut some key areas

Science.gov (United States)

Showstack, Randy

2012-03-01

The White House's proposed fiscal year (FY) 2013 budget for the National Oceanic and Atmospheric Administration (NOAA), announced on 13 February, looks favorable at first glance. The administration's request calls for $5.1 billion, an increase of $153 million (3.1%) above the FY 2012 estimated budget. However, the increase for NOAA satellites is $163 million, which means that other areas within the agency would be slated for decreased funding, including programs within the National Ocean Service (NOS), National Marine Fisheries Service (NMFS), National Weather Service (NWS), and some NOAA education programs. The proposed overall budget for the agency “reflects the overarching importance of weather satellites to public safety, to national security, and to the economy,” NOAA director Jane Lubchenco said at a 16 February briefing, noting that difficult choices were made regarding the budget. “Due to significant resources required for our weather satellites and the economic conditions in the country, other parts of our budget have been reduced, in some cases quite significantly,” she said. She added that the imperative to fund both the Joint Polar Satellite System (JPSS) and geostationary satellites in FY 2013 “imposes serious constraints on the rest of NOAA's budget.”

Radiation-hard mid-power booster optical fiber amplifiers for high-speed digital and analogue satellite laser communication links

Science.gov (United States)

Stampoulidis, L.; Kehayas, E.; Stevens, G.; Henwood-Moroney, L.; Hosking, P.; Robertson, A.

2017-11-01

Optical laser communications (OLC) has been identified as the technology to enable high-data rate, secure links between and within satellites, as well as between satellites and ground stations with decreased mass, size, and electrical power compared to traditional RF technology.

Modulation/demodulation techniques for satellite communications. Part 1: Background

Science.gov (United States)

Omura, J. K.; Simon, M. K.

1981-01-01

Basic characteristics of digital data transmission systems described include the physical communication links, the notion of bandwidth, FCC regulations, and performance measurements such as bit rates, bit error probabilities, throughputs, and delays. The error probability performance and spectral characteristics of various modulation/demodulation techniques commonly used or proposed for use in radio and satellite communication links are summarized. Forward error correction with block or convolutional codes is also discussed along with the important coding parameter, channel cutoff rate.

Review of Research Shows, Overall, Acupuncture Did Not Increase Pregnancy Rates with IVF

Science.gov (United States)

... did seem to increase pregnancy success rates at IVF clinics with baseline pregnancy rates that were lower than 32 percent. This review, funded in part by NCCAM, was published online in the journal Human Reproduction Update. The review analyzed 16 randomized controlled clinical ...

Shale gas activity and increased rates of sexually transmitted infections in Ohio, 2000-2016.

Directory of Open Access Journals (Sweden)

Nicole C Deziel

Full Text Available The growing shale gas ("fracking" industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis.We conducted a longitudinal, ecologic study from 2000-2016 in Ohio, situated in a prolific shale gas region in the United States (US. Data on reported cases of chlamydia, gonorrhea, and syphilis by county and year were obtained from the Ohio Department of Health. All 88 counties were classified as none, low, and high shale gas activity in each year, using data from the Ohio Department of Natural Resources. Annual rate ratios (RR and 95% confidence intervals (95% CIs were calculated from mixed-effects Poisson regression models evaluating the relationship between shale gas activity and reported annual STI rates while adjusting for secular trends and potential confounders obtained from the US Census.Compared to counties with no shale gas activity, counties with high activity had 21% (RR = 1.21; 95%CI = 1.08-1.36 increased rates of chlamydia and 19% (RR = 1.27; 95%CI 0.98-1.44 increased rates of gonorrhea, respectively. No association was observed for syphilis.This first report of a link between shale gas activity and increased rates of both chlamydia and gonorrhea may inform local policies and community health efforts.

Interim Service ISDN Satellite (ISIS) hardware experiment development for advanced ISDN satellite designs and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

The Skeletal Muscle Satellite Cell

Science.gov (United States)

2011-01-01

The skeletal muscle satellite cell was first described and named based on its anatomic location between the myofiber plasma and basement membranes. In 1961, two independent studies by Alexander Mauro and Bernard Katz provided the first electron microscopic descriptions of satellite cells in frog and rat muscles. These cells were soon detected in other vertebrates and acquired candidacy as the source of myogenic cells needed for myofiber growth and repair throughout life. Cultures of isolated myofibers and, subsequently, transplantation of single myofibers demonstrated that satellite cells were myogenic progenitors. More recently, satellite cells were redefined as myogenic stem cells given their ability to self-renew in addition to producing differentiated progeny. Identification of distinctively expressed molecular markers, in particular Pax7, has facilitated detection of satellite cells using light microscopy. Notwithstanding the remarkable progress made since the discovery of satellite cells, researchers have looked for alternative cells with myogenic capacity that can potentially be used for whole body cell-based therapy of skeletal muscle. Yet, new studies show that inducible ablation of satellite cells in adult muscle impairs myofiber regeneration. Thus, on the 50th anniversary since its discovery, the satellite cell’s indispensable role in muscle repair has been reaffirmed. PMID:22147605

The investigation of tethered satellite system dynamics

Science.gov (United States)

Lorenzini, E. C.

1986-01-01

The analysis of the rotational dynamics of the satellite was focused on the rotational amplitude increase of the satellite, with respect to the tether, during retrieval. The dependence of the rotational amplitude upon the tether tension variation to the power 1/4 was thoroughly investigated. The damping of rotational oscillations achievable by reel control was also quantified while an alternative solution that makes use of a lever arm attached with a universal joint to the satellite was proposed. Comparison simulations between the Smithsonian Astrophysical Observatory and the Martin Marietta (MMA) computer code of reteival maneuvers were also carried out. The agreement between the two, completely independent, codes was extremely close, demonstrating the reliability of the models. The slack tether dynamics during reel jams was analytically investigated in order to identify the limits of applicability of the SLACK3 computer code to this particular case. Test runs with SLACK3 were also carried out.

Surgical Space Suits Increase Particle and Microbiological Emission Rates in a Simulated Surgical Environment.

Science.gov (United States)

Vijaysegaran, Praveen; Knibbs, Luke D; Morawska, Lidia; Crawford, Ross W

2018-05-01

The role of space suits in the prevention of orthopedic prosthetic joint infection remains unclear. Recent evidence suggests that space suits may in fact contribute to increased infection rates, with bioaerosol emissions from space suits identified as a potential cause. This study aimed to compare the particle and microbiological emission rates (PER and MER) of space suits and standard surgical clothing. A comparison of emission rates between space suits and standard surgical clothing was performed in a simulated surgical environment during 5 separate experiments. Particle counts were analyzed with 2 separate particle counters capable of detecting particles between 0.1 and 20 μm. An Andersen impactor was used to sample bacteria, with culture counts performed at 24 and 48 hours. Four experiments consistently showed statistically significant increases in both PER and MER when space suits are used compared with standard surgical clothing. One experiment showed inconsistent results, with a trend toward increases in both PER and MER when space suits are used compared with standard surgical clothing. Space suits cause increased PER and MER compared with standard surgical clothing. This finding provides mechanistic evidence to support the increased prosthetic joint infection rates observed in clinical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

78 FR 63128 - Dried Prunes Produced in California; Increased Assessment Rate

Science.gov (United States)

2013-10-23

...; Increased Assessment Rate AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed rule. SUMMARY: This... the Regulatory Flexibility Act (RFA) (5 U.S.C. 601-612), the Agricultural Marketing Service (AMS) has... prunes. Dated: October 17, 2013. Rex A. Barnes, Associate Administrator, Agricultural Marketing Service...

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…

76 FR 591 - Determination of Rates and Terms for Preexisting Subscription and Satellite Digital Audio Radio...

Science.gov (United States)

2011-01-05

... with the $150 filing fee, must be addressed to: Copyright Royalty Board, P.O. Box 70977, Washington, DC..., parties must pay the filing fee with a check or money order made payable to the ``Copyright Royalty Board... LIBRARY OF CONGRESS Copyright Royalty Board [Docket No. 2011-1 CRB PSS/Satellite II] Determination...

Nano-Satellite Secondary Spacecraft on Deep Space Missions

Science.gov (United States)

Klesh, Andrew T.; Castillo-Rogez, Julie C.

2012-01-01

NanoSat technology has opened Earth orbit to extremely low-cost science missions through a common interface that provides greater launch accessibility. They have also been used on interplanetary missions, but these missions have used one-off components and architectures so that the return on investment has been limited. A natural question is the role that CubeSat-derived NanoSats could play to increase the science return of deep space missions. We do not consider single instrument nano-satellites as likely to complete entire Discovery-class missions alone,but believe that nano-satellites could augment larger missions to significantly increase science return. The key advantages offered by these mini-spacecrafts over previous planetary probes is the common availability of advanced subsystems that open the door to a large variety of science experiments, including new guidance, navigation and control capabilities. In this paper, multiple NanoSat science applications are investigated, primarily for high risk/high return science areas. We also address the significant challenges and questions that remain as obstacles to the use of nano-satellites in deep space missions. Finally, we provide some thoughts on a development roadmap toward interplanetary usage of NanoSpacecraft.

Increased use of lethal methods and annual increase of suicide rates in Korean adolescents: comparison with adolescents in the United States.

Science.gov (United States)

Park, Subin; Cho, Soo-Churl; Kim, Bung-Nyun; Kim, Jae-Won; Yoo, Hee Jeong; Hong, Jin Pyo

2014-03-01

The lethality of the suicide method is a strong risk factor for completed suicide. We examined whether the annual change in the pattern of suicide methods was related to the annual change in suicide rates among adolescents in South Korea and the United States. We analyzed annual data for the 2000-2009 period for South Korea and the 2000-2008 period for the United States to examine time trends in the suicide rates and suicide methods of adolescents aged 10-19 years in two countries. Data on suicide methods were obtained from the World Health Organization (WHO) mortality database. Suicide rates among adolescents in the United States have remained relatively steady since 2000, whereas the suicide among Korean adolescents has increased. Between 2000 and 2009, the most common suicide method among Korean adolescents was jumping for boys and girls, whereas it was hanging for girls and firearms for boys in the United States. Along with the annual increase in suicide rates in South Korea, the incidences of jumping among males and hanging (and recently jumping) among females have increased steadily, whereas suicide by self-poisoning steadily decreased. In the United States, between 2000 and 2008, the proportion of suicides committed by hanging increased, whereas those committed using firearms steadily decreased, particularly among adolescent females. These findings suggest that the increased use of lethal suicide methods is reflected in the increase in suicide rates in Korean adolescents. The most fruitful approach to addressing the rises in jumping suicides among Korean adolescents and hanging suicides among adolescents in the United States may be through population-based initiatives to reduce the physical availability (e.g., limiting access to or fencing off tall structures) and the social acceptability (e.g., effective and responsible regulations for reporting suicide) of these methods. © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association

Adaptive spatial filtering for daytime satellite quantum key distribution

Science.gov (United States)

Gruneisen, Mark T.; Sickmiller, Brett A.; Flanagan, Michael B.; Black, James P.; Stoltenberg, Kurt E.; Duchane, Alexander W.

2014-11-01

The rate of secure key generation (SKG) in quantum key distribution (QKD) is adversely affected by optical noise and loss in the quantum channel. In a free-space atmospheric channel, the scattering of sunlight into the channel can lead to quantum bit error ratios (QBERs) sufficiently large to preclude SKG. Furthermore, atmospheric turbulence limits the degree to which spatial filtering can reduce sky noise without introducing signal losses. A system simulation quantifies the potential benefit of tracking and higher-order adaptive optics (AO) technologies to SKG rates in a daytime satellite engagement scenario. The simulations are performed assuming propagation from a low-Earth orbit (LEO) satellite to a terrestrial receiver that includes an AO system comprised of a Shack-Hartmann wave-front sensor (SHWFS) and a continuous-face-sheet deformable mirror (DM). The effects of atmospheric turbulence, tracking, and higher-order AO on the photon capture efficiency are simulated using statistical representations of turbulence and a time-domain waveoptics hardware emulator. Secure key generation rates are then calculated for the decoy state QKD protocol as a function of the receiver field of view (FOV) for various pointing angles. The results show that at FOVs smaller than previously considered, AO technologies can enhance SKG rates in daylight and even enable SKG where it would otherwise be prohibited as a consequence of either background optical noise or signal loss due to turbulence effects.

Activities of Canadian Satellite Communications, Inc.

Science.gov (United States)

1992-12-01

Canadian Satellite Communications (Cancom) has as its core business the provision of television and radio signals to cable systems in Canada, with the objective of making affordable broadcast signals available to remote and/or small communities. Cancom also provides direct-to-home services to backyard receiving dishes, as well as satellite digital data business communications services, satellite business television, and satellite network services. Its business communication services range from satellite links for big-city businesses with small branch operations located far from major centers, to a mobile messaging and tracking system for the trucking industry. Revenues in 1992 totalled $48,212,000 and net income was just over $7 million. Cancom bought 10 percent interest in Leosat Corp. of Washington, DC, who are seeking approval to operate a position locator network from low-orbit satellites. Cancom has also become a partner in SovCan Star Satellite Communications Inc., which will build an international satellite system in partnership with Russia. The first satellite in this east-west business network will be placed in a Russian orbital slot over the Atlantic by 1996, and a second satellite will follow for the Pacific region. This annual report of Cancom's activities for 1992 includes financial statements and a six year financial review.

76 FR 7095 - Avocados Grown in South Florida; Increased Assessment Rate

Science.gov (United States)

2011-02-09

... FIR] Avocados Grown in South Florida; Increased Assessment Rate AGENCY: Agricultural Marketing Service... established for the Avocado Administrative Committee (Committee), for the 2010-11 and subsequent fiscal periods from $0.27 to $0.37 per 55-pound bushel container of Florida avocados handled. The Committee...

75 FR 67607 - Dried Prunes Produced in California; Increased Assessment Rate

Science.gov (United States)

2010-11-03

... Order 12988, Civil Justice Reform. Under the marketing order now in effect, California dried prune... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 993 [Doc. No. AMS-FV-10-0057... Marketing Service, USDA. ACTION: Final rule. SUMMARY: This rule increases the assessment rate established...

Introduction to the Personal Access Satellite System Study

Science.gov (United States)

Sue, Miles K.

1990-01-01

A recent study by the National Telecommunications and Information Administration (NTIA) has concluded that the 21st century will be the age of information in which the telecommunication infrastructure will be vital to the social and economic well being of society. To meet the challenge of the coming age, JPL has been performing studies on a personal access satellite system (PASS) for the 21st century. The PASS study can be traced back to a study in which the technical feasibility and potential applications of a high frequency, low data rate satellite system were identified using small fixed terminals. Herein, the PASS concept is described along with the strawman design. Then the key challenges are identified along with possible solutions. Finally, the plan for the future is summarized from the key results.

Satellite services system overview

Science.gov (United States)

Rysavy, G.

1982-01-01

The benefits of a satellite services system and the basic needs of the Space Transportation System to have improved satellite service capability are identified. Specific required servicing equipment are discussed in terms of their technology development status and their operative functions. Concepts include maneuverable television systems, extravehicular maneuvering unit, orbiter exterior lighting, satellite holding and positioning aid, fluid transfer equipment, end effectors for the remote manipulator system, teleoperator maneuvering system, and hand and power tools.

Mobility management in satellite networks

Science.gov (United States)

Johanson, Gary A.

1995-01-01

This paper addresses the methods used or proposed for use in multi-beam and/or multi-satellite networks designed to provide Mobile Satellite Services (MSS). Specific topics include beam crossover in the North American Mobile Satellite (MSAT) system as well as registration and live call hand-off for a multi-regional geosynchronous (GEO) satellite based system and a global coverage Low Earth Orbiting (LEO) system. In the MSAT system, the individual satellite beams cover very large geographic areas so the need for live call hand-off was not anticipated. This paper discusses the methods used to keep track of the beam location of the users so that incoming call announcements or other messages may be directed to them. Proposed new GEO systems with large numbers of beams will provide much smaller geographic coverage in individual beams and thus the need arises to keep track of the user's location as well as to provide live call hand-off as the user traverses from beam to beam. This situation also occurs in proposed LEO systems where the problems are worsened by the need for satellite to satellite hand-off as well as beam to beam hand-off within a single satellite. The paper discusses methods to accomplish these handoffs and proposes system architectures to address the various hand-off scenarios.

GAS LOSS BY RAM PRESSURE STRIPPING AND INTERNAL FEEDBACK FROM LOW-MASS MILKY WAY SATELLITES

Energy Technology Data Exchange (ETDEWEB)

Emerick, Andrew; Low, Mordecai-Mark Mac [Department of Astronomy, Columbia University, New York, NY (United States); Grcevich, Jana [Department of Astrophysics, American Museum of Natural History, New York, NY (United States); Gatto, Andrea [Max-Planck-Institute für Astrophysik, Garching, bei München (Germany)

2016-08-01

The evolution of dwarf satellites in the Milky Way (MW) is affected by a combination of ram pressure stripping (RPS), tidal stripping, and internal feedback from massive stars. We investigate gas loss processes in the smallest satellites of the MW using three-dimensional, high-resolution, idealized wind tunnel simulations, accounting for gas loss through both ram pressure stripping and expulsion by supernova feedback. Using initial conditions appropriate for a dwarf galaxy like Leo T, we investigate whether or not environmental gas stripping and internal feedback can quench these low-mass galaxies on the expected timescales, shorter than 2 Gyr. We find that supernova feedback contributes negligibly to the stripping rate for these low star formation rate galaxies. However, we also find that RPS is less efficient than expected in the stripping scenarios we consider. Our work suggests that although RPS can eventually completely strip these galaxies, other physics is likely at play to reconcile our computed stripping times with the rapid quenching timescales deduced from observations of low-mass MW dwarf galaxies. We discuss the roles additional physics may play in this scenario, including host-satellite tidal interactions, cored versus cuspy dark matter profiles, reionization, and satellite preprocessing. We conclude that a proper accounting of these physics together is necessary to understand the quenching of low-mass MW satellites.

Variability in the mechanisms controlling Southern Ocean phytoplankton bloom phenology in an ocean model and satellite observations

Science.gov (United States)

Rohr, Tyler; Long, Matthew C.; Kavanaugh, Maria T.; Lindsay, Keith; Doney, Scott C.

2017-05-01

A coupled global numerical simulation (conducted with the Community Earth System Model) is used in conjunction with satellite remote sensing observations to examine the role of top-down (grazing pressure) and bottom-up (light, nutrients) controls on marine phytoplankton bloom dynamics in the Southern Ocean. Phytoplankton seasonal phenology is evaluated in the context of the recently proposed "disturbance-recovery" hypothesis relative to more traditional, exclusively "bottom-up" frameworks. All blooms occur when phytoplankton division rates exceed loss rates to permit sustained net population growth; however, the nature of this decoupling period varies regionally in Community Earth System Model. Regional case studies illustrate how unique pathways allow blooms to emerge despite very poor division rates or very strong grazing rates. In the Subantarctic, southeast Pacific small spring blooms initiate early cooccurring with deep mixing and low division rates, consistent with the disturbance-recovery hypothesis. Similar systematics are present in the Subantarctic, southwest Atlantic during the spring but are eclipsed by a subsequent, larger summer bloom that is coincident with shallow mixing and the annual maximum in division rates, consistent with a bottom-up, light limited framework. In the model simulation, increased iron stress prevents a similar summer bloom in the southeast Pacific. In the simulated Antarctic zone (70°S-65°S) seasonal sea ice acts as a dominant phytoplankton-zooplankton decoupling agent, triggering a delayed but substantial bloom as ice recedes. Satellite ocean color remote sensing and ocean physical reanalysis products do not precisely match model-predicted phenology, but observed patterns do indicate regional variability in mechanism across the Atlantic and Pacific.

The Effects of Increased Accountability Standards on Graduation Rates for Students with Disabilities

Science.gov (United States)

Moore, Mitzi Lee

2012-01-01

This research sought to determine if unintended effects of increased accountability standards on graduation rates for students with disabilities existed. Data from one southeastern state were utilized in order to determine if graduation rates were impacted as a result of higher accountability standards. In addition, administrator attitudes on…

Annual survival rate estimate of satellite transmitter–marked eastern population greater sandhill cranes

Science.gov (United States)

Fronczak, David L.; Andersen, David E.; Hanna, Everett E.; Cooper, Thomas R.

2015-01-01

Several surveys have documented the increasing population size and geographic distribution of Eastern Population greater sandhill cranes Grus canadensis tabida since the 1960s. Sport hunting of this population of sandhill cranes started in 2012 following the provisions of the Eastern Population Sandhill Crane Management Plan. However, there are currently no published estimates of Eastern Population sandhill crane survival rate that can be used to inform harvest management. As part of two studies of Eastern Population sandhill crane migration, we deployed solar-powered global positioning system platform transmitting terminals on Eastern Population sandhill cranes (n  =  42) at key concentration areas from 2009 to 2012. We estimated an annual survival rate for Eastern Population sandhill cranes from data resulting from monitoring these cranes by using the known-fates model in the MARK program. Estimated annual survival rate for adult Eastern Population sandhill cranes was 0.950 (95% confidence interval  =  0.885–0.979) during December 2009–August 2014. All fatalities (n  =  5) occurred after spring migration in late spring and early summer. We were unable to determine cause of death for crane fatalities in our study. Our survival rate estimate will be useful when combined with other population parameters such as the population index derived from the U.S. Fish and Wildlife Service fall survey, harvest, and recruitment rates to assess the effects of harvest on population size and trend and evaluate the effectiveness of management strategies.

78 FR 23671 - Onions Grown in South Texas; Increased Assessment Rate

Science.gov (United States)

2013-04-22

... behalf. There are approximately 85 producers of onions in the production area and approximately 30... FR] Onions Grown in South Texas; Increased Assessment Rate AGENCY: Agricultural Marketing Service... Texas Onion Committee (Committee) for the 2012-13 and subsequent fiscal periods from $0.025 to $0.03 per...

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...

Development and validation of satellite-based estimates of surface visibility

Science.gov (United States)

Brunner, J.; Pierce, R. B.; Lenzen, A.

2016-02-01

A satellite-based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5 % for classifying clear (V ≥ 30 km), moderate (10 km ≤ V United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

Development and validation of satellite based estimates of surface visibility

Science.gov (United States)

Brunner, J.; Pierce, R. B.; Lenzen, A.

2015-10-01

A satellite based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5% for classifying Clear (V ≥ 30 km), Moderate (10 km ≤ V United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network, and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

Increased mortality by septicemia, interstitial pneumonitis and pulmonary fibrosis among bone marrow transplant recipients receiving an increased mean dose rate of total irradiation

International Nuclear Information System (INIS)

Ringden, O.; Baaryd, I.; Johansson, B.

1983-01-01

Seven bone marrow transplant recipients with acute lymphoblastic leukemia receiving a mean dose rate of 0.07 Gy/min of total body irradiation towards the pelvic midpoint and the lungs had an increased (p<0.01) overall death rate of 86 per cent compared with 33 per cent among 27 patients with acute non-lymphoblastic leukemia or acute lymphoblastic leukemia treated with a mean dose rate of 0.04 Gy/min. Among the patients receiving the higher dose rate there was an increased mortality in causes related to radiation toxicity like early septicemia, interstitial pneumonitis and pulmonary fibrosis, compared with all patients receiving the lower dose rate (p<0.01) and also with 10 patients from this group with acute lymphoblastic leukemia (p<0.02). (Auth.)

An energy-saving development initiative increases birth rate and childhood malnutrition in rural Ethiopia.

Directory of Open Access Journals (Sweden)

Mhairi A Gibson

2006-04-01

Full Text Available Evolutionary life history theory predicts that, in the absence of contraception, any enhancement of maternal condition can increase human fertility. Energetic trade-offs are likely to be resolved in favour of maximizing reproductive success rather than health or longevity. Here we find support for the hypothesis that development initiatives designed to improve maternal and child welfare may also incur costs associated with increased family sizes if they do not include a family planning component.Demographic and anthropometric data were collected in a rural Ethiopian community benefiting from a recent labour-saving development technology that reduces women's energetic expenditure (n = 1,976 households. Using logistic hazards models and general linear modelling techniques, we found that whilst infant mortality has declined, the birth rate has increased, causing greater scarcity of resources within households.This study is, to our knowledge, the first to demonstrate a link between a technological development intervention and an increase in both birth rate and childhood malnutrition. Women's nutritional status was not improved by the energy-saving technology, because energy was diverted into higher birth rates. We argue that the contribution of biological processes to increased birth rates in areas of the developing world without access to modern contraception has been overlooked. This highlights the continued need for development programmes to be multisectoral, including access to and promotion of contraception.

Korea Earth Observation Satellite Program

Science.gov (United States)

Baek, Myung-Jin; Kim, Zeen-Chul

via Korea Aerospace Research Institute (KARI) as the prime contractor in the area of Korea earth observation satellite program to enhance Korea's space program development capability. In this paper, Korea's on-going and future earth observation satellite programs are introduced: KOMPSAT- 1 (Korea Multi Purpose Satellite-1), KOMPSAT-2 and Communication, Broadcasting and Meteorological Satellite (CBMS) program. KOMPSAT-1 satellite successfully launched in December 1999 with Taurus launch vehicle. Since launch, KOMPSAT-1 is downlinking images of Korea Peninsular every day. Until now, KOMPSAT-1 has been operated more than 2 and half years without any major hardware malfunction for the mission operation. KOMPSAT-1 payload has 6.6m panchromatic spatial resolution at 685 km on-orbit and the spacecraft bus had NASA TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe) spacecraft bus heritage designed and built by TRW, U.S.A.KOMPSAT-1 program was international co-development program between KARI and TRW funded by Korean Government. be launched in 2004. Main mission objective is to provide geo-information products based on the multi-spectral high resolution sensor called Multi-Spectral Camera (MSC) which will provide 1m panchromatic and 4m multi-spectral high resolution images. ELOP of Israel is the prime contractor of the MSC payload system and KARI is the total system prime contractor including spacecraft bus development and ground segment. KARI also has the contract with Astrium of Europe for the purpose of technical consultation and hardware procurement. Based on the experience throughout KOMPSAT-1 and KOMPSAT-2 space system development, Korea is expecting to establish the infrastructure of developing satellite system. Currently, KOMPSAT-2 program is in the critical design stage. are scheduled to launch in 2008 and in 2014, respectively. The mission of CBMS consists of two areas. One is of space technology test for the communications mission, and the other is of a real

Assessing water availability over peninsular Malaysia using public domain satellite data products

International Nuclear Information System (INIS)

Ali, M I; Hashim, M; Zin, H S M

2014-01-01

Water availability monitoring is an essential task for water resource sustainability and security. In this paper, the assessment of satellite remote sensing technique for determining water availability is reported. The water-balance analysis is used to compute the spatio-temporal water availability with main inputs; the precipitation and actual evapotranspiration rate (AET), both fully derived from public-domain satellite products of Tropical Rainfall Measurement Mission (TRMM) and MODIS, respectively. Both these satellite products were first subjected to calibration to suit corresponding selected local precipitation and AET samples. Multi-temporal data sets acquired 2000-2010 were used in this study. The results of study, indicated strong agreement of monthly water availability with the basin flow rate (r 2 = 0.5, p < 0.001). Similar agreements were also noted between the estimated annual average water availability with the in-situ measurement. It is therefore concluded that the method devised in this study provide a new alternative for water availability mapping over large area, hence offers the only timely and cost-effective method apart from providing comprehensive spatio-temporal patterns, crucial in water resource planning to ensure water security

Increase in the rate and uniformity of coastline erosion in Arctic Alaska

Science.gov (United States)

Jones, Benjamin M.; Arp, C.D.; Jorgenson, M.T.; Hinkel, Kenneth M.; Schmutz, J.A.; Flint, P.L.

2009-01-01

Analysis of a 60 km segment of the Alaskan Beaufort Sea coast using a time-series of aerial photography revealed that mean annual erosion rates increased from 6.8 m a-1 (1955 to 1979), to 8.7 m a-1 (1979 to 2002), to 13.6 m a-1 (2002 to 2007). We also observed that spatial patterns of erosion have become more uniform across shoreline types with different degrees of ice-richness. Further, during the remainder of the 2007 ice-free season 25 m of erosion occurred locally, in the absence of a westerly storm event. Concurrent arctic changes potentially responsible for this shift in the rate and pattern of land loss include declining sea ice extent, increasing summertime sea surface temperature, rising sea-level, and increases in storm power and corresponding wave action. Taken together, these factors may be leading to a new regime of ocean-land interactions that are repositioning and reshaping the Arctic coastline. Copyright 2009 by the American Geophysical Union.

Satellite-Based Sunshine Duration for Europe

Directory of Open Access Journals (Sweden)

Bodo Ahrens

2013-06-01

Full Text Available In this study, two different methods were applied to derive daily and monthly sunshine duration based on high-resolution satellite products provided by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring using data from Meteosat Second Generation (MSG SEVIRI (Spinning Enhanced Visible and Infrared Imager. The satellite products were either hourly cloud type or hourly surface incoming direct radiation. The satellite sunshine duration estimates were not found to be significantly different using the native 15-minute temporal resolution of SEVIRI. The satellite-based sunshine duration products give additional spatial information over the European continent compared with equivalent in situ-based products. An evaluation of the satellite sunshine duration by product intercomparison and against station measurements was carried out to determine their accuracy. The satellite data were found to be within ±1 h/day compared to high-quality Baseline Surface Radiation Network or surface synoptic observations (SYNOP station measurements. The satellite-based products differ more over the oceans than over land, mainly because of the treatment of fractional clouds in the cloud type-based sunshine duration product. This paper presents the methods used to derive the satellite sunshine duration products and the performance of the different retrievals. The main benefits and disadvantages compared to station-based products are also discussed.

The precision of today's satellite laser ranging systems

Science.gov (United States)

Dunn, Peter J.; Torrence, Mark H.; Hussen, Van S.; Pearlman, Michael R.

1993-06-01

Recent improvements in the accuracy of modern satellite laser ranging (SLR) systems are strengthened by the new capability of many instruments to track an increasing number of geodetic satellite targets without significant scheduling conflict. This will allow the refinement of some geophysical parameters, such as solid Earth tidal effects and GM, and the improved temporal resolution of others, such as Earth orientation and station position. Better time resolution for the locations of fixed observatories will allow us to monitor more subtle motions at the stations, and transportable systems will be able to provide indicators of long term trends with shorter occupations. If we are to take advantage of these improvements, care must be taken to preserve the essential accuracy of an increasing volume of range observations at each stage of the data reduction process.

Development of a hardware-in-loop attitude control simulator for a CubeSat satellite

Science.gov (United States)

Tapsawat, Wittawat; Sangpet, Teerawat; Kuntanapreeda, Suwat

2018-01-01

Attitude control is an important part in satellite on-orbit operation. It greatly affects the performance of satellites. Testing of an attitude determination and control subsystem (ADCS) is very challenging since it might require attitude dynamics and space environment in the orbit. This paper develops a low-cost hardware-in-loop (HIL) simulator for testing an ADCS of a CubeSat satellite. The simulator consists of a numerical simulation part, a hardware part, and a HIL interface hardware unit. The numerical simulation part includes orbital dynamics, attitude dynamics and Earth’s magnetic field. The hardware part is the real ADCS board of the satellite. The simulation part outputs satellite’s angular velocity and geomagnetic field information to the HIL interface hardware. Then, based on this information, the HIL interface hardware generates I2C signals mimicking the signals of the on-board rate-gyros and magnetometers and consequently outputs the signals to the ADCS board. The ADCS board reads the rate-gyro and magnetometer signals, calculates control signals, and drives the attitude actuators which are three magnetic torquers (MTQs). The responses of the MTQs sensed by a separated magnetometer are feedback to the numerical simulation part completing the HIL simulation loop. Experimental studies are conducted to demonstrate the feasibility and effectiveness of the simulator.

Satellite Communications Industry

Science.gov (United States)

1993-04-01

Ariane $loom SAJAC 1 Hughes Satellite Japan 06/94 $150m SAJAC 2 Hughes Satellite Japan -- (spare) $150m SatcomHl GE GE Americom /95 $50m SOLIDARIDAD ...1 Hughes SCT (Mexico) 11/93 Ariane $loom SOLIDARIDAD 2 Hughes SCT (Mexico) /94 $loom Superbird Al Loral Space Com Gp (Jap) 11/92 Ariane $175m

Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

International Nuclear Information System (INIS)

Abdel-Aziz, Yehia A.; Shoaib, Muhammad

2014-01-01

The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ 0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated. (research papers)

Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

Science.gov (United States)

Abdel-Aziz, Yehia A.; Shoaib, Muhammad

2014-07-01

The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated.

78 FR 8047 - Onions Grown in South Texas; Increased Assessment Rate

Science.gov (United States)

2013-02-05

... Executive Order 12988, Civil Justice Reform. Under the marketing order now in effect, South Texas onion... DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 959 [Doc. No. AMS-FV-12-0039; FV12-959-1 PR] Onions Grown in South Texas; Increased Assessment Rate AGENCY: Agricultural Marketing...

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.

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.

Laser experiments in light cloudiness with the geostationary satellite ARTEMIS

Science.gov (United States)

Kuzkov, V.; Kuzkov, S.; Sodnik, Z.

2016-08-01

The geostationary satellite ARTEMIS was launched in July 2001. The satellite is equipped with a laser communication terminal, which was used for the world's first inter-satellite laser communication link between ARTEMIS and the low earth orbit satellite SPOT-4. Ground-to-space laser communication experiments were also conducted under various atmospheric conditions involving ESA's optical ground station. With a rapidly increasing volume of information transferred by geostationary satellites, there is a rising demand for high-speed data links between ground stations and satellites. For ground-to-space laser communications there are a number of important design parameters that need to be addressed, among them, the influence of atmospheric turbulence in different atmospheric conditions and link geometries. The Main Astronomical Observatory of NAS of Ukraine developed a precise computer tracking system for its 0.7 m AZT-2 telescope and a compact laser communication package LACES (Laser Atmosphere and Communication experiments with Satellites) for laser communication experiments with geostationary satellites. The specially developed software allows computerized tracking of the satellites using their orbital data. A number of laser experiments between MAO and ARTEMIS were conducted in partial cloudiness with some amount of laser light observed through clouds. Such conditions caused high break-up (splitting) of images from the laser beacon of ARTEMIS. One possible explanation is Raman scattering of photons on molecules of a water vapor in the atmosphere. Raman scattering causes a shift in a wavelength of the photons.In addition, a different value for the refraction index appears in the direction of the meridian for the wavelength-shifted photons. This is similar to the anomalous atmospheric refraction that appears at low angular altitudes above the horizon. We have also estimated the atmospheric attenuation and the influence of atmospheric turbulence on observed results

Muscle satellite cell heterogeneity and self-renewal

Science.gov (United States)

Motohashi, Norio; Asakura, Atsushi

2014-01-01

Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD) patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD. PMID:25364710

Muscle Satellite Cell Heterogeneity and Self-Renewal

Directory of Open Access Journals (Sweden)

Norio eMotohashi

2014-01-01

Full Text Available Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD.

Sharply increased mass loss from glaciers and ice caps in the Canadian Arctic Archipelago.

Science.gov (United States)

Gardner, Alex S; Moholdt, Geir; Wouters, Bert; Wolken, Gabriel J; Burgess, David O; Sharp, Martin J; Cogley, J Graham; Braun, Carsten; Labine, Claude

2011-05-19

Mountain glaciers and ice caps are contributing significantly to present rates of sea level rise and will continue to do so over the next century and beyond. The Canadian Arctic Archipelago, located off the northwestern shore of Greenland, contains one-third of the global volume of land ice outside the ice sheets, but its contribution to sea-level change remains largely unknown. Here we show that the Canadian Arctic Archipelago has recently lost 61 ± 7 gigatonnes per year (Gt yr(-1)) of ice, contributing 0.17 ± 0.02 mm yr(-1) to sea-level rise. Our estimates are of regional mass changes for the ice caps and glaciers of the Canadian Arctic Archipelago referring to the years 2004 to 2009 and are based on three independent approaches: surface mass-budget modelling plus an estimate of ice discharge (SMB+D), repeat satellite laser altimetry (ICESat) and repeat satellite gravimetry (GRACE). All three approaches show consistent and large mass-loss estimates. Between the periods 2004-2006 and 2007-2009, the rate of mass loss sharply increased from 31 ± 8 Gt yr(-1) to 92 ± 12 Gt yr(-1) in direct response to warmer summer temperatures, to which rates of ice loss are highly sensitive (64 ± 14 Gt yr(-1) per 1 K increase). The duration of the study is too short to establish a long-term trend, but for 2007-2009, the increase in the rate of mass loss makes the Canadian Arctic Archipelago the single largest contributor to eustatic sea-level rise outside Greenland and Antarctica.

Rain Fade Compensation for Ka-Band Communications Satellites

Science.gov (United States)

Mitchell, W. Carl; Nguyen, Lan; Dissanayake, Asoka; Markey, Brian; Le, Anh

1997-01-01

This report provides a review and evaluation of rain fade measurement and compensation techniques for Ka-band satellite systems. This report includes a description of and cost estimates for performing three rain fade measurement and compensation experiments. The first experiment deals with rain fade measurement techniques while the second one covers the rain fade compensation techniques. The third experiment addresses a feedback flow control technique for the ABR service (for ATM-based traffic). The following conclusions were observed in this report; a sufficient system signal margin should be allocated for all carriers in a network, that is a fixed clear-sky margin should be typically in the range of 4-5 dB and should be more like 15 dB in the up link for moderate and heavy rain zones; to obtain a higher system margin it is desirable to combine the uplink power control technique with the technique that implements the source information rate and FEC code rate changes resulting in a 4-5 dB increase in the dynamic part of the system margin. The experiments would assess the feasibility of the fade measurements and compensation techniques, and ABR feedback control technique.

High-rate injection is associated with the increase in U.S. mid-continent seismicity

Science.gov (United States)

Weingarten, Matthew; Ge, Shemin; Godt, Jonathan W.; Bekins, Barbara A.; Rubinstein, Justin L.

2015-01-01

An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well’s cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

Satellite precipitation estimation over the Tibetan Plateau

Science.gov (United States)

Porcu, F.; Gjoka, U.

2012-04-01

Precipitation characteristics over the Tibetan Plateau are very little known, given the scarcity of reliable and widely distributed ground observation, thus the satellite approach is a valuable choice for large scale precipitation analysis and hydrological cycle studies. However,the satellite perspective undergoes various shortcomings at the different wavelengths used in atmospheric remote sensing. In the microwave spectrum often the high soil emissivity masks or hides the atmospheric signal upwelling from light-moderate precipitation layers, while low and relatively thin precipitating clouds are not well detected in the visible-infrared, because of their low contrast with cold and bright (if snow covered) background. In this work an IR-based, statistical rainfall estimation technique is trained and applied over the Tibetan Plateau hydrological basin to retrive precipitation intensity at different spatial and temporal scales. The technique is based on a simple artificial neural network scheme trained with two supervised training sets assembled for monsoon season and for the rest of the year. For the monsoon season (estimated from June to September), the ground radar precipitation data for few case studies are used to build the training set: four days in summer 2009 are considered. For the rest of the year, CloudSat-CPR derived snowfall rate has been used as reference precipitation data, following the Kulie and Bennartz (2009) algorithm. METEOSAT-7 infrared channels radiance (at 6.7 and 11 micometers) and derived local variability features (such as local standard deviation and local average) are used as input and the actual rainrate is obtained as output for each satellite slot, every 30 minutes on the satellite grid. The satellite rainrate maps for three years (2008-2010) are computed and compared with available global precipitation products (such as C-MORPH and TMPA products) and with other techniques applied to the Plateau area: similarities and differences are

Baicalin prevents Candida albicans infections via increasing its apoptosis rate

International Nuclear Information System (INIS)

Yang, Shulong; Fu, Yingyuan; Wu, Xiuzhen; Zhou, Zhixing; Xu, Jing; Zeng, Xiaoping; Kuang, Nanzhen; Zeng, Yurong

2014-01-01

Highlights: • Baicalin increases the ratio of the G0/G1 stages and C. albicans apoptosis. • Baicalin decreases the proliferation index of C. albicans. • Baicalin inhibits the biosynthesis of DNA, RNA and protein in C. albicans. • Baicalin depresses Succinate Dehydrogenase and Ca 2+ –Mg 2+ ATPase in C. albicans. • Baicalin increases the endocytic free Ca 2+ concentration in C. albicans. - Abstract: Background: These experiments were employed to explore the mechanisms underlying baicalin action on Candida albicans. Methodology and principal findings: We detected the baicalin inhibition effects on three isotope-labeled precursors of 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C. albicans using the isotope incorporation technology. The activities of Succinate Dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca 2+ –Mg 2+ ATPase, cytosolic Ca 2+ concentration, the cell cycle and apoptosis, as well as the ultrastructure of C.albicans were also tested. We found that baicalin inhibited 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C.albicans (P < 0.005). The activities of the SDH and Ca 2+ –Mg 2+ ATPase of C.albicans in baicalin groups were lower than those in control group (P < 0.05). Ca 2+ concentrations of C. albicans in baicalin groups were much higher than those in control group (P < 0.05). The ratio of C.albicans at the G0/G1 stage increased in baicalin groups in dose dependent manner (P < 0.01). There were a significant differences in the apoptosis rate of C.albicans between baicalin and control groups (P < 0.01). After 12–48 h incubation with baicalin (1 mg/ml), C. albicans shown to be markedly damaged under transmission electron micrographs. Innovation and significance: Baicalin can increase the apoptosis rate of C. albicans. These effects of Baicalin may involved in its inhibiting the activities of the SDH and Ca 2+ –Mg 2+ ATPase, increasing cytosolic Ca 2+ content and damaging the ultrastructure of C. albicans

Satellite communications network design and analysis

CERN Document Server

Jo, Kenneth Y

2011-01-01

This authoritative book provides a thorough understanding of the fundamental concepts of satellite communications (SATCOM) network design and performance assessments. You find discussions on a wide class of SATCOM networks using satellites as core components, as well as coverage key applications in the field. This in-depth resource presents a broad range of critical topics, from geosynchronous Earth orbiting (GEO) satellites and direct broadcast satellite systems, to low Earth orbiting (LEO) satellites, radio standards and protocols.This invaluable reference explains the many specific uses of

Satellites You Can See for Homework

Science.gov (United States)

Broderick, Stephen

2012-01-01

Artificial satellites are easily observed most nights when the weather is fine. The website called "Heavens Above" at www.heavens-above.com will help locate these satellites flying over one's location. It also includes how bright they will appear. The direction of travel of each satellite in the night sky also indicates the type of satellite. For…

Tension waves in tethered satellite cables

Science.gov (United States)

Lallman, F. J.

1984-01-01

A one-degree-of-freedom simulation of the Tethered Satellite System (TSS) was programmed using a distributed system model of the tether based on the one-dimensional wave equation. This model represents the time varying tension profile along the tether as the sum of two traveling waves of tension moving in opposite directions. A control loop was devised which combines a deployment rate command with the measured tension at the deployer to produce a smooth, stable rate of deployment of the subsatellite. Simulation results show a buildup of periodic bursts of high frequency oscillation in tension. This report covers the mathematical modelling and simulation results and explains the reason for the observed oscillations. The design of a possible vibration damping device is discussed.

University Satellite Consortium and Space Education in Japan Centered on Micro-Nano Satellites

Science.gov (United States)

Nakasuka, S.; Kawashima, R.

2002-01-01

in Japan especially centered on micro or nano class satellites. Hands-on training using micro-nano satellites provide unique opportunity of space education to university level students, by giving them a chance to experience the whole space project cycle from mission creation, satellite design, fabrication, test, launch, operation through analysis of the results. Project management and team working are other important skills that can be trained in these projects. include 1) low cost, which allows one laboratory in university to carry out a project, 2) short development period such as one or two year, which enables students to obtain the results of their projects before they graduate, and 3) small size and weight, which enables fabrication and test within usually very narrow university laboratory areas. In Japan, several projects such as CanSat, CubeSat or Whale Observation Satellite have been carried out, proving that micro-nano satellites provide very unique and valuable educational opportunity. with the objective to make a university student and staff community of these micro-nano satellite related activities in Japan. This consortium aims for many activities including facilitating information and skills exchange and collaborations between member universities, helping students to use ground test facilities of national laboratories, consulting them on political or law related matters, coordinating joint development of equipments or projects, and bridging between these university activities and the needs or interests of the people in general. This kind of outreach activity is essential because how to create missions of micro-nano satellites should be pursued in order for this field to grow larger than a merely educational enterprise. The final objectives of the consortium is to make a huge community of the users, mission creators, investors and manufactures(i.e., university students) of micro-nano satellites, and provide a unique contribution to the activation of

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...

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 1

Science.gov (United States)

Greenburg, J. S.; Gaelick, C.; Kaplan, M.; Fishman, J.; Hopkins, C.

1985-01-01

Commercial organizations as well as government agencies invest in spacecraft (S/C) technology programs that are aimed at increasing the performance of communications satellites. The value of these programs must be measured in terms of their impacts on the financial performane of the business ventures that may ultimately utilize the communications satellites. An economic evaluation and planning capability was developed and used to assess the impact of NASA on-orbit propulsion and space power programs on typical fixed satellite service (FSS) and direct broadcast service (DBS) communications satellite business ventures. Typical FSS and DBS spin and three-axis stabilized spacecraft were configured in the absence of NASA technology programs. These spacecraft were reconfigured taking into account the anticipated results of NASA specified on-orbit propulsion and space power programs. In general, the NASA technology programs resulted in spacecraft with increased capability. The developed methodology for assessing the value of spacecraft technology programs in terms of their impact on the financial performance of communication satellite business ventures is described. Results of the assessment of NASA specified on-orbit propulsion and space power technology programs are presented for typical FSS and DBS business ventures.

Does global warning increase establishment rates of invasive alien species? A centurial time series analysis

Science.gov (United States)

Dingcheng Huang; Robert A. Haack; Runzhi. Zhang

2011-01-01

The establishment rate of invasive alien insect species has been increasing worldwide during the past century. This trend has been widely attributed to increased rates of international trade and associated species introductions, but rarely linked to environmental change. To better understand and manage the bioinvasion process, it is crucial to understand the...

Collage of Saturn's smaller satellites

Science.gov (United States)

1981-01-01

This family portrait shows the smaller satellites of Saturn as viewed by Voyager 2 during its swing through the Saturnian system. The following chart corresponds to this composite photograph (distance from the planet increases from left to right) and lists names, standard numerical designations and approximate dimensions (radii where indicated) in kilometers: 1980S26Outer F-ringshepherd120 X 100 1980S1Leadingco-orbital220 X 160 1980S25TrailingTethys trojanradii: 25 1980S28Outer Ashepherdradii: 20 1980S27Inner F-ringco-orbital145 X 70 1980S3TrailingTethys trojan140 X 100 1980S13LeadingTethys trojanradii: 30 1980S6LeadingDione trojanradii: 30 These images have been scaled to show the satellites in true relative sizes. This set of small objects ranges in size from small asteroidal scales to nearly the size of Saturn's moon Mimas. They are probably fragments of somewhat larger bodies broken up during the bombardment period that followed accretion of the Saturnian system. Scientists believe they may be mostly icy bodies with a mixture of meteorite rock. They are somewhat less reflective than the larger satellites, suggesting that thermal evolution of the larger moons 'cleaned up' their icy surfaces. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

Multi-Band Multi-Tone Tunable Millimeter-Wave Frequency Synthesizer For Satellite Beacon Transmitter

Science.gov (United States)

Simons, Rainee N.; Wintucky, Edwin G.

2016-01-01

This paper presents the design and test results of a multi-band multi-tone tunable millimeter-wave frequency synthesizer, based on a solid-state frequency comb generator. The intended application of the synthesizer is in a satellite beacon transmitter for radio wave propagation studies at K-band (18 to 26.5 GHz), Q-band (37 to 42 GHz), and E-band (71 to 76 GHz). In addition, the architecture for a compact beacon transmitter, which includes the multi-tone synthesizer, polarizer, horn antenna, and power/control electronics, has been investigated for a notional space-to-ground radio wave propagation experiment payload on a small satellite. The above studies would enable the design of robust high throughput multi-Gbps data rate future space-to-ground satellite communication links.

First report of satellite males during breeding in Leptodactylus latrans (Amphibia, Anura

Directory of Open Access Journals (Sweden)

Gabriel Laufer

2014-05-01

Full Text Available The occurrence of satellite males is a common behaviour across anuran taxa. Satellite males take peripheral positions to calling males and adopt tactics in an attempt to intercept females that are attracted to calling males to increase their own mating success. Satellite males could have an inexpensive form of mate-locating, avoiding predators, and saving energy. Furthermore, this strategy could play an important role in the genetic structure of populations. The genus Leptodactylus consists of approximately 70 described species that are widely distributed in South America. The literature on the biology of this genus is extensive; however, we found only two reports on the existence of multi-male mating behavior in the genus (L. chaquensis and L. podicipinus. Herein, we report intrasexual competition in the form of satellite behavior in Leptodactylus latrans, where multiple satellite males were observed in close vicinity to a calling male.

Protocol and Topology Issues for Wide-Area Satellite Interconnection of Terrestrial Optical LANs

Science.gov (United States)

Parraga, N.

2002-01-01

Apart from broadcasting, the satellite business is targeting niche markets. Wide area interconnection is considered as one of these niche markets, since it addresses operators and business LANs (B2B, business to business) in remote areas where terrestrial infrastructure is not available. These LANs - if high-speed - are typically based on optical networks such as SONET. One of the advantages of SONET is its architecture flexibility and capacity to transport all kind of applications including multimedia with a range of different transmission rates. The applications can be carried by different protocols among which the Internet Protocol (IP) or the Asynchronous Transfer Mode (ATM) are the most prominent ones. Thus, the question arises how these protocols can be interconnected via the satellite segment. The paper addresses several solutions for interworking with different protocols. For this investigation we distinguish first of all between the topology and the switching technology of the satellites. In case of a star network with transparent satellite, the satellite protocol consists of physical layer and data layer which can be directly interconnected with layer 2 interworking function to their terrestrial counterparts in the SONET backbone. For regenerative satellites the situation is more complex: here we need to distinguish the types of transport protocols being used in the terrestrial and satellite segment. Whereas IP, ATM, MPEG dominate in the terrestrial networks, satellite systems usually do not follow these standards. Some might employ minor additions (for instance, satellite specific packet headers), some might be completely proprietary. In general, interworking must be done for the data plane on top of layer 2 (data link layer), whereas for the signaling plane the interworking is on top of layer 3. In the paper we will discuss the protocol stacks for ATM, IP, and MPEG with a regenerative satellite system. As an example we will use the EuroSkyWay satellite

Climatology of the Occurrence Rate and Amplitudes of Local Time Distinguished Equatorial Plasma Depletions Observed by Swarm Satellite

Science.gov (United States)

Wan, Xin; Xiong, Chao; Rodriguez-Zuluaga, Juan; Kervalishvili, Guram N.; Stolle, Claudia; Wang, Hui

2018-04-01

In this study, we developed an autodetection technique for the equatorial plasma depletions (EPDs) and their occurrence and depletion amplitudes based on in situ electron density measurements gathered by Swarm A satellite. For the first time, comparisons are made among the detected EPDs and their amplitudes with the loss of Global Positioning System (GPS) signal of receivers onboard Swarm A, and the Swarm Level-2 product, Ionospheric Bubble Index (IBI). It has been found that the highest rate of EPD occurrence takes place generally between 2200 and 0000 magnetic local time (MLT), in agreement with the IBI. However, the largest amplitudes of EPD are detected earlier at about 1900-2100 MLT. This coincides with the moment of higher background electron density and the largest occurrence of GPS signal loss. From a longitudinal perspective, the higher depletion amplitude is always witnessed in spatial bins with higher background electron density. At most longitudes, the occurrence rate of postmidnight EPDs is reduced compared to premidnight ones; while more postmidnight EPDs are observed at African longitudes. CHAMP observations confirm this point regardless of high or low solar activity condition. Further by comparing with previous studies and the plasma vertical drift velocity from ROCSAT-1, we suggest that while the F region vertical plasma drift plays a key role in dominating the occurrence of EPDs during premidnight hours, the postmidnight EPDs are the combined results from the continuing of former EPDs and newborn EPDs, especially during June solstice. And these newborn EPDs during postmidnight hours seem to be less related to the plasma vertical drift.

New Methods for Air Quality Model Evaluation with Satellite Data

Science.gov (United States)

Holloway, T.; Harkey, M.

2015-12-01

Despite major advances in the ability of satellites to detect gases and aerosols in the atmosphere, there remains significant, untapped potential to apply space-based data to air quality regulatory applications. Here, we showcase research findings geared toward increasing the relevance of satellite data to support operational air quality management, focused on model evaluation. Particular emphasis is given to nitrogen dioxide (NO2) and formaldehyde (HCHO) from the Ozone Monitoring Instrument aboard the NASA Aura satellite, and evaluation of simulations from the EPA Community Multiscale Air Quality (CMAQ) model. This work is part of the NASA Air Quality Applied Sciences Team (AQAST), and is motivated by ongoing dialog with state and federal air quality management agencies. We present the response of satellite-derived NO2 to meteorological conditions, satellite-derived HCHO:NO2 ratios as an indicator of ozone production regime, and the ability of models to capture these sensitivities over the continental U.S. In the case of NO2-weather sensitivities, we find boundary layer height, wind speed, temperature, and relative humidity to be the most important variables in determining near-surface NO2 variability. CMAQ agreed with relationships observed in satellite data, as well as in ground-based data, over most regions. However, we find that the southwest U.S. is a problem area for CMAQ, where modeled NO2 responses to insolation, boundary layer height, and other variables are at odds with the observations. Our analyses utilize a software developed by our team, the Wisconsin Horizontal Interpolation Program for Satellites (WHIPS): a free, open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates level 2 satellite retrievals onto a user-defined fixed grid, in effect creating custom-gridded level 3 satellite product. Currently, WHIPS can process the following data products: OMI NO2 (NASA retrieval); OMI NO2 (KNMI retrieval); OMI

Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

Directory of Open Access Journals (Sweden)

Hyungjik Oh

2016-03-01

Full Text Available This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.

Design and Fabrication of DebriSat - A Representative LEO Satellite for Improvements to Standard Satellite Breakup Models

Science.gov (United States)

Clark, S.; Dietrich, A.; Fitz-Coy, N.; Weremeyer, M.; Liou, J.-C.

2012-01-01

This paper discusses the design and fabrication of DebriSat, a 50 kg satellite developed to be representative of a modern low Earth orbit satellite in terms of its components, materials used, and fabrication procedures. DebriSat will be the target of a future hypervelocity impact experiment to determine the physical characteristics of debris generated after an on-orbit collision of a modern LEO satellite. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was SOCIT, conducted in 1992. The target used for that experiment was a Navy transit satellite (40 cm, 35 kg) fabricated in the 1960's. Modern satellites are very different in materials and construction techniques than those built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. To ensure that DebriSat is truly representative of typical LEO missions, a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 1 kg to 5000 kg was conducted. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions. Although DebriSat is an engineering model, specific attention is placed on the quality, type, and quantity of the materials used in its fabrication to ensure the integrity of the outcome. With the exception of software, all other aspects of the satellite s design, fabrication, and assembly integration and testing will be as rigorous as that of an actual flight vehicle. For example, to simulate survivability of launch loads, DebriSat will be subjected to a vibration test. As well, the satellite will undergo thermal vacuum tests to verify that the components and overall systems meet typical environmental standards. Proper assembly and integration techniques will involve comprehensive joint analysis, including the precise

Forecasting the impact of an 1859-caliber superstorm on geosynchronous Earth-orbiting satellites: Transponder resources

Science.gov (United States)

Odenwald, Sten F.; Green, James L.

2007-06-01

We calculate the economic impact on the existing geosynchronous Earth-orbiting satellite population of an 1859-caliber superstorm event were it to occur between 2008 and 2018 during the next solar activity cycle. From a detailed model for transponder capacity and leasing, we have investigated the total revenue loss over the entire solar cycle, as a function of superstorm onset year and intensity. Our Monte Carlo simulations of 1000 possible superstorms, of varying intensity and onset year, suggest that the minimum revenue loss could be of the order of 30 billion. The losses would be larger than this if more that 20 satellites are disabled, if future launch rates do not keep up with the expected rate of retirements, or if the number of spare transponders falls below ˜30%. Consequently, revenue losses can be significantly reduced below 30 billion if the current satellite population undergoes net growth beyond 300 units during Solar Cycle 24 and a larger margin of unused transponders is maintained.

Characterizing SPDY over High Latency Satellite Channels

Directory of Open Access Journals (Sweden)

Luca Caviglione

2014-12-01

Full Text Available The increasing complexity ofWeb contents and the growing diffusion of mobile terminals, which use wireless and satellite links to get access to the Internet, impose the adoption of more specialized protocols. In particular, we focus on SPDY, a novel protocol introduced by Google to optimize the retrieval of complex webpages, to manage large Round Trip Times and high packet losses channels. In this perspective, the paper characterizes SPDY over high latency satellite links, especially with the goal of understanding whether it could be an efficient solution to cope with performance degradations typically affecting Web 2.0 services. To this aim, we implemented an experimental set-up, composed of an ad-hoc proxy, a wireless link emulator, and an instrumented Web browser. The results clearly indicate that SPDY can enhance the performances in terms of loading times, and reduce the traffic fragmentation. Moreover, owing to its connection multiplexing architecture, SPDY can also mitigate the transport layer complexity, which is critical when in presence of Performance Enhancing Proxies usually deployed to isolate satellite trunks.

Social marketing as a strategy to increase immunization rates.

Science.gov (United States)

Opel, Douglas J; Diekema, Douglas S; Lee, Nancy R; Marcuse, Edgar K

2009-05-01

Today in the United States, outbreaks of vaccine-preventable disease are often traced to susceptible children whose parents have claimed an exemption from school or child care immunization regulations. The origins of this immunization hesitancy and resistance have roots in the decline of the threat of vaccine-preventable disease coupled with an increase in concerns about the adverse effects of vaccines, the emergence of mass media and the Internet, and the intrinsic limitations of modern medicine. Appeals to emotion have drowned out thoughtful discussion in public forums, and overall, public trust in immunizations has declined. We present an often overlooked behavior change strategy-social marketing-as a way to improve immunization rates by addressing the important roots of immunization hesitancy and effectively engaging emotions. As an example, we provide a synopsis of a social marketing campaign that is currently in development in Washington state and that is aimed at increasing timely immunizations in children from birth to age 24 months.

Satellite failures revisited

Science.gov (United States)

Balcerak, Ernie

2012-12-01

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

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....

Normalization and calibration of geostationary satellite radiances for the International Satellite Cloud Climatology Project

Science.gov (United States)

Desormeaux, Yves; Rossow, William B.; Brest, Christopher L.; Campbell, G. G.

1993-01-01

Procedures are described for normalizing the radiometric calibration of image radiances obtained from geostationary weather satellites that contributed data to the International Satellite Cloud Climatology Project. The key step is comparison of coincident and collocated measurements made by each satellite and the concurrent AVHRR on the 'afternoon' NOAA polar-orbiting weather satellite at the same viewing geometry. The results of this comparison allow transfer of the AVHRR absolute calibration, which has been established over the whole series, to the radiometers on the geostationary satellites. Results are given for Meteosat-2, 3, and 4, for GOES-5, 6, and 7, for GMS-2, 3, and 4 and for Insat-1B. The relative stability of the calibrations of these radiance data is estimated to be within +/- 3 percent; the uncertainty of the absolute calibrations is estimated to be less than 10 percent. The remaining uncertainties are at least two times smaller than for the original radiance data.

Contrast in low-cost operational concepts for orbiting satellites

Science.gov (United States)

Walyus, Keith D.; Reis, James; Bradley, Arthur J.

2002-12-01

Older spacecraft missions, especially those in low Earth orbit with telemetry intensive requirements, required round-the-clock control center staffing. The state of technology relied on control center personnel to continually examine data, make decisions, resolve anomalies, and file reports. Hubble Space Telescope (HST) is a prime example of this description. Technological advancements in hardware and software over the last decade have yielded increases in productivity and operational efficiency, which result in lower cost. The re-engineering effort of HST, which has recently concluded, utilized emerging technology to reduce cost and increase productivity. New missions, of which NASA's Transition Region and Coronal Explorer Satellite (TRACE) is an example, have benefited from recent technological advancements and are more cost-effective than when HST was first launched. During its launch (1998) and early orbit phase, the TRACE Flight Operations Team (FOT) employed continually staffed operations. Yet once the mission entered its nominal phase, the FOT reduced their staffing to standard weekday business hours. Operations were still conducted at night and during the weekends, but these operations occurred autonomously without compromising their high standards for data collections. For the HST, which launched in 1990, reduced cost operations will employ a different operational concept, when the spacecraft enters its low-cost phase after its final servicing mission in 2004. Primarily due to the spacecraft"s design, the HST Project has determined that single-shift operations will introduce unacceptable risks for the amount of dollars saved. More importantly, significant cost-savings can still be achieved by changing the operational concept for the FOT, while still maintaining round-the-clock staffing. It"s important to note that the low-cost solutions obtained for one satellite may not be applicable for other satellites. This paper will contrast the differences between

Satellite Cell Self-Renewal.

Science.gov (United States)

Giordani, Lorenzo; Parisi, Alice; Le Grand, Fabien

2018-01-01

Adult skeletal muscle is endowed with regenerative potential through partially recapitulating the embryonic developmental program. Upon acute injury or in pathological conditions, quiescent muscle-resident stem cells, called satellite cells, become activated and give rise to myogenic progenitors that massively proliferate, differentiate, and fuse to form new myofibers and restore tissue functionality. In addition, a proportion of activated cells returns back to quiescence and replenish the pool of satellite cells in order to maintain the ability of skeletal muscle tissue to repair. Self-renewal is the process by which stem cells divide to make more stem cells to maintain the stem cell population throughout life. This process is controlled by cell-intrinsic transcription factors regulated by cell-extrinsic signals from the niche and the microenvironment. This chapter provides an overview about the general aspects of satellite cell biology and focuses on the cellular and molecular aspects of satellite cell self-renewal. To date, we are still far from understanding how a very small proportion of the satellite cell progeny maintain their stem cell identity when most of their siblings progress through the myogenic program to construct myofibers. © 2018 Elsevier Inc. All rights reserved.