The EC-ASEAN COGEN programme

Energy Technology Data Exchange (ETDEWEB)

Pennington, M.; Lacrosse, L. [Asian Institute of Technology (Thailand); Schenkel, Y. [Centre de Recherches Agronomiques (Belgium)

1996-12-31

The EC-ASEAN COGEN Programme is a co-operation programme between the European Commission (EC) and the Association of South East Asian Nations (ASEAN) co-ordinated by the Asian Institute of Technology (AIT), Bangkok, Thailand. Its aim is to accelerate the implementation of proven technologies generating heat and/or power from wood and agroindustrial residues through partnerships between European and ASEAN companies. (orig.)

The EC-ASEAN COGEN programme

Energy Technology Data Exchange (ETDEWEB)

Pennington, M; Lacrosse, L [Asian Institute of Technology (Thailand); Schenkel, Y [Centre de Recherches Agronomiques (Belgium)

1997-12-31

The EC-ASEAN COGEN Programme is a co-operation programme between the European Commission (EC) and the Association of South East Asian Nations (ASEAN) co-ordinated by the Asian Institute of Technology (AIT), Bangkok, Thailand. Its aim is to accelerate the implementation of proven technologies generating heat and/or power from wood and agroindustrial residues through partnerships between European and ASEAN companies. (orig.)

Evaluation of the size segregation of elemental carbon (EC emission in Europe: influence on the simulation of EC long-range transportation

Directory of Open Access Journals (Sweden)

Y. Chen

2016-02-01

Full Text Available Elemental Carbon (EC has a significant impact on human health and climate change. In order to evaluate the size segregation of EC emission in the EUCAARI inventory and investigate its influence on the simulation of EC long-range transportation in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number and/or mass size distributions were evaluated with observations at the central European background site Melpitz. The fine mode particle concentration was reasonably well simulated, but the coarse mode was substantially overestimated by the model mainly due to the plume with high EC concentration in coarse mode emitted by a nearby point source. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that the coarse mode EC (ECc emitted from the nearby point sources might be overestimated by a factor of 2–10. The fraction of ECc was overestimated in the emission inventory by about 10–30 % for Russia and 5–10 % for Eastern Europe (e.g., Poland and Belarus. This incorrect size-dependent EC emission results in a shorter atmospheric life time of EC particles and inhibits the long-range transport of EC. A case study showed that this effect caused an underestimation of 20–40 % in the EC mass concentration in Germany under eastern wind pattern.

Roles of major organizations in EC for decision making. EC no ishi kettei ni okeru shuyo kikan no yakuwari

Energy Technology Data Exchange (ETDEWEB)

Kodama, M.

1992-12-01

This paper considers authorization powers held by the major organizations in the EC, with the Maastricht Treaty kept in mind. One of the objectives of establishing the EC is to harmonize and develop the economic activities in the community on the whole, and promote making closer the relations among the member nations. The EC's supernationality has two aspects: finances (using financial sources from externally common tariffs as the EC's independent financial resources) and legislations (member nations delegating their own powers to the international organization). Organizations involving in the EC legislations are the European Assembly, the board of ministers, and the EC Committee. The Assembly has deciding powers at high levels on the EC budget decision, as well as vetoing power on the budget. The board of ministers is provided with deciding powers to assure achievement of the objectives defined in the official requirements. The Committee has a supernational character that each committee member can act independently free from being subjected to orders from his or her native country. Practically, however, the authorization relationship among the organizations has confrontations over the interests of the organizations and member nations. There have been such movements in this situation as the Luxemburg compromises, actions at the agricultural ministers meeting, and preparation of the unified European protocol. 2 figs., 4 tabs.

Public Availability to ECS Collected Datasets

Science.gov (United States)

Henderson, J. F.; Warnken, R.; McLean, S. J.; Lim, E.; Varner, J. D.

2013-12-01

Coastal nations have spent considerable resources exploring the limits of their extended continental shelf (ECS) beyond 200 nm. Although these studies are funded to fulfill requirements of the UN Convention on the Law of the Sea, the investments are producing new data sets in frontier areas of Earth's oceans that will be used to understand, explore, and manage the seafloor and sub-seafloor for decades to come. Although many of these datasets are considered proprietary until a nation's potential ECS has become 'final and binding' an increasing amount of data are being released and utilized by the public. Data sets include multibeam, seismic reflection/refraction, bottom sampling, and geophysical data. The U.S. ECS Project, a multi-agency collaboration whose mission is to establish the full extent of the continental shelf of the United States consistent with international law, relies heavily on data and accurate, standard metadata. The United States has made it a priority to make available to the public all data collected with ECS-funding as quickly as possible. The National Oceanic and Atmospheric Administration's (NOAA) National Geophysical Data Center (NGDC) supports this objective by partnering with academia and other federal government mapping agencies to archive, inventory, and deliver marine mapping data in a coordinated, consistent manner. This includes ensuring quality, standard metadata and developing and maintaining data delivery capabilities built on modern digital data archives. Other countries, such as Ireland, have submitted their ECS data for public availability and many others have made pledges to participate in the future. The data services provided by NGDC support the U.S. ECS effort as well as many developing nation's ECS effort through the U.N. Environmental Program. Modern discovery, visualization, and delivery of scientific data and derived products that span national and international sources of data ensure the greatest re-use of data and

Dual EC : a standardized back door

NARCIS (Netherlands)

Bernstein, D.J.; Lange, T.; Niederhagen, R.F.

2015-01-01

Dual EC is an algorithm to compute pseudorandom numbers starting from some random input. Dual EC was standardized by NIST, ANSI, and ISO among other algorithms to generate pseudorandom numbers. For a long time this algorithm was considered suspicious -- the entity designing the algorithm could have

Programming Amazon EC2

CERN Document Server

Vliet, Jurg

2011-01-01

If you plan to use Amazon Web Services to run applications in the cloud, the end-to-end approach in this book will save you needless trial and error. You'll find practical guidelines for designing and building applications with Amazon Elastic Compute Cloud (EC2) and a host of supporting AWS tools, with a focus on critical issues such as load balancing, monitoring, and automation. How do you move an existing application to AWS, or design your application so that it scales effectively? How much storage will you require? Programming Amazon EC2 not only helps you get started, it will also keep y

Evaluation of the size segregation of elemental carbon (EC) emission in Europe: Influence on the simulation of EC long-range transportation

NARCIS (Netherlands)

Chen, Y.; Cheng, Y.F.; Nordmann, S.; Birmili, W.; Denier Van Der Gon, H.A.C.; Ma, N.; Wolke, R.; Wehner, B.; Sun, J.; Spindler, G.; Mu, Q.; Pöschl, U.; Su, H.; Wiedensohler, A.

2016-01-01

Elemental Carbon (EC) has a significant impact on human health and climate change. In order to evaluate the size segregation of EC emission in the EUCAARI inventory and investigate its influence on the simulation of EC long-range transportation in Europe, we used the fully coupled online Weather

The EC discourse on vocational training

DEFF Research Database (Denmark)

Cort, Pia

2009-01-01

This article traces the EC vocational training policy historically and describes the discursive alignments which brought the policy from a ‘common vocational training policy' as laid down in Article 128, in the Treaty of Rome to the Lisbon Lifelong Learning strategy. The argument is that vocational...... EC vocational training policy (Ball, What is policy? Texts, trajectories and toolboxes. Discourse, 13(2), 1993)....

Finite impulse testing (FIT) system for Emergency Cooling System (ECS) in Dhruva

International Nuclear Information System (INIS)

Punekar, Parag; Ramkumar, N.; Kulkarni, U.S.; Darbhea, M.D.; Bharadhwaj, G; Jangra, L.R.; Geetha, Patil; Das, Shantanu; Sonnis, S.T.; Trevedi, P.; Patil, M.B.; Biswas, B.B.

2006-01-01

Finite Impulse Testing (FIT) system for Emergency Cooling System (ECS) is used to check healthiness of ECS logic circuits in an online mode. The ECS is an important safety system that ensures the cooling of reactor core during shutdown state of Main Coolant Pumps (MCPs), and hence FIT-ECS that monitors the health of ECS logic circuits in an online (real time) mode is an important part of it. Based on a Safety Related Unusual Occurrence in ECS system due to the malfunction of its earlier single channel FIT system, the new FIT-ECS system has been designed with new features and is commissioned. The FIT-ECS system feeds the simulated input signals (fine impulses of nominal width 575 μS) to the ECS logic circuits and read the outputs. These output (predicted) signals from ECS logic circuit are processed in the FIT-ECS system and in event of any discrepancy, the FIT-ECS system displays fault signature on local panel, detailed information of the fault on Operator Console (OC), and generates an alarm 'ECS logic Fail' in the control room. FIT-ECS also monitors the inputs and outputs of ECS logic circuit. All the information required is stored as a database that can be subsequently displayed in various formats. ECS system is designated as Category I-A system and is a hardwired system and FIT-ECS monitors the healthiness of the logics of the ECS System is a computerized system. As per IEC 1226, FIT-ECS is categorized as Category I-B system. This paper provides technical information on FIT-ECS system design, its important features, the testing carried on the FIT-ECS system, interconnections of FIT-ECS and ECS and the commissioning experience of FIT-ECS system. (author)

Everyone talk about EC technology - What's about this technology? AC versus AC technology; Alle reden von EC-Technologie - was bringt sie wirklich? AC- versus EC-Motorentechnik

Energy Technology Data Exchange (ETDEWEB)

Anon.

2010-12-15

Meanwhile, the EC motor technology is the state of the art in fans. In the consciousness of a possible energy conservation, the EC motor technology is demanded to a large extent with the new installations of the customers. But how high are the possible savings actually? A comparative measurement at a condenser of Guentner AG (Fuerstenfeldbruck, Federal Republic of Germany) supports information.

On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Science.gov (United States)

Currie, L. A.; Kessler, J. D.

2005-10-01

The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of

On the isolation of elemental carbon (EC for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK EC isolation procedure

Directory of Open Access Journals (Sweden)

L. A. Currie

2005-01-01

Full Text Available The primary objective of the research reported here has been the development of a hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of 'soot' (EC, the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust, showed a range of results, but since the 'truth' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC of measurement validity (Currie et al., 2002. Components of the new Hybrid RM (DiesApple, however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically. NIST SRM 2975 (Forklift Diesel Soot has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK and thermal optical transmission (TOT methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS. As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1 both methods exhibited biomass-C 'leakage'; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC isolated contained about 3% of the original biomass-C.; (2 the initial isothermal oxidation stage

EC-construction product guideline 89/106/EEC and EC-pressure equipement guideline 97/23/EC; EG-Bauproduktenrichtlinie 89/106/EWG und EG-Druckgeraeterichtlinie 97/23/EG

Energy Technology Data Exchange (ETDEWEB)

Dupin, F. [DVGW Deutscher Verein des Gas- und Wasserfaches e.V., Bonn (Germany)

1998-08-01

For now nearly ten years the EC-directive 90/396/EEC is well established in the gas field. In the meantime other EC-directives are playing a role which cannot be left out of consideration. Particularly the EC-Construction Product Directive (89/106/EEC) and the Pressure Equipment Directive (97/23/EG) constitute a focal point as many key-issues (e.g. scope) are still open, causing thus hotly debated discussions. The present contribution reflects the current consultations at the national and European level, pointing out then the gas-specific features. (orig.) [Deutsch] Seit nahezu zehn Jahren hat sich die EG-Richtlinie 90/396/EWG fuer Gasverbrauchseinrichtungen im europaeischen Gasfach fest etabliert. Inzwischen sind andere EG-Richtlinien ins Spiel gekommen, deren Einfluss nicht ausser Acht gelassen werden kann. Besonders die EG-Bauproduktenrichtlinie (89/106/EWG) und die EG-Druckgeraeterichtlinie (97/23/EG) stehen z.Z. im Mittelpunkt, da viele Schluesselfragen (z.B. Geltungsbereich) noch offen sind und heftige Debatten mit sich bringen. Der vorliegende Beitrag gibt den Stand der auf nationaler und europaeischer Ebene gefuehrten Beratungen wieder und stellt dabei die gasspezifischen Gegebenheiten heraus. (orig.)

Special Issue: Selected papers from ECS'97

DEFF Research Database (Denmark)

1999-01-01

This Special Issue of Analog Integrated Circuits and Signal Processing presents extended versions of selected papers from the First Electronic Circuits and Systems Conference (ECS'97) which was held on September 4-5, 1997, in Bratislava, Slovakia.......This Special Issue of Analog Integrated Circuits and Signal Processing presents extended versions of selected papers from the First Electronic Circuits and Systems Conference (ECS'97) which was held on September 4-5, 1997, in Bratislava, Slovakia....

EC6 design features and pre-project licensing review

Energy Technology Data Exchange (ETDEWEB)

Yu, S.; Lee, A.G.; Dinh, N.B.; Soulard, M. [CANDU Energy Inc., Mississauga, Ontario, (Canada)

2013-07-01

The Enhanced CANDU 6 (EC6) is the new Generation III CANDU reactor design that meets the most up to date Canadian regulatory requirements and customer expectations. Candu Energy Inc. is finalizing development of the EC6 which incorporates the CANDU 6's well-proven features, and adds enhancements that strengthened reactor safety margin and improved operability. The EC6 builds on the proven high performance design and the defence-in-depth features of CANDU 6 units, and has incorporated extensive operational feedback including lessons learned from Fukushima. This paper will provide status of the engineering program including progress on the pre-licensing review of the EC6 design by the Canadian Regulator, CNSC, and will also highlight the design and safety enhancements incorporated in the EC6 product. Safety enhancements to meet safety goals and to improve robustness of systems to respond to design basis accidents and beyond design basis accidents include: new severe accident recovery and heat removal system; improved emergency heat removal system; faster shutoff rods with improved safety margins; mechanical guaranteed shutdown rods; daily load cycling capability; robust containment with containment filter venting system; and improved backed-up electrical supply and cooling services. (author)

Do Decision 2003/54/EC and Decision no. 1229/2003/EC result in a European market for electricity?

International Nuclear Information System (INIS)

Wenting, F.

2004-01-01

In the summer of 2003 the European Parliament and the European Council issued a new Directive with respect to the internal market for electricity (Directive 2003/54/EC of the European Parliament and of the Council of 26 June 2003 concerning common rules for the internal market in electricity) and Guidelines for trans-European networks in the energy sector (Decision no. 1229/2003/EC). The question is whether these decisions will lead to a European and free market for electricity. It is concluded that this is not yet the case [nl

Seizure threshold to lidocaine is decreased following repeated ECS (electroconvulsive shock)

DEFF Research Database (Denmark)

Kragh, J; Seidelin, J; Bolwig, T G

1993-01-01

Seizure susceptibility to lidocaine was investigated in rats which had received repeated ECS (electroconvulsive shock). In the first experiment three groups of rats received an ECS daily for 18 days, an ECS weekly for 18 weeks, and 18 sham treatments, respectively. Twelve weeks after the last ECS...... all rats received a lidocaine challenge (LC) in the form of an intraperitoneal (IP) injection of lidocaine (65 mg/kg). After the injection the animals were observed for occurrence of motor seizures. A total of 67% (10/15), 47% (7/15), and 0% (0/18) of the daily, weekly, and sham groups, respectively......, had motor seizures in response to the LC. In the second experiment five groups of rats received an ECS daily for 0, 1, 6, 18, and 36 days, respectively. Eighteen weeks after the last ECS all rats received an LC and 0% (0/15), 13% (2/15), 20% (3/15), 53% (8/15), and 58% (7/12), respectively, developed...

Ketone EC50 values in the Microtox test.

Science.gov (United States)

Chen, H F; Hee, S S

1995-03-01

The Microtox EC50 values for the following ketones are reported in the following homologous series: straight chain methyl ketones (acetone, 2-butanone, 2-pentanone, 2-hepatonone, 2-octanone, 2-decanone, and 2-tridecanone); methyl ketones substituted at one alpha carbon (3-methyl-2-butanone; 3,3-dimethyl-2-butanone); methyl substituted at two alpha carbons (2,4-dimethyl-3-pentanone; 2,2,4,4-tetramethyl-3-pentanone); phenyl groups replacing methyl in acetone (acetophenone; benzophenone); methyl groups substituted at the alpha carbons of cyclohexanone; and 2,3- 2,4-, and 2,5-hexanediones, most for the first time. While there were linear relationships between log EC50 and MW for the straight chain methyl ketones, and for methyl substitution at the alpha carbon for methyl ketones, there were no other linear relationships. As molecular weight increased, the EC50 values of soluble ketones decreased; as distance between two carbonyl groups decreased so too did EC50 values. Thus, for the ketones the geometry around the carbonyl group is an important determinant of toxicity as well as MW, water solubility, and octanol/water coefficient.

Nuclear power plant performance in the EC in 1978

International Nuclear Information System (INIS)

Anon.

1979-01-01

According to the report presented by the Statistical Office of the Ec, nuclear electricity generation in the nine EC countries has been increased in 1978 by 11% to a net value of 115 TWh as compared to the year before. Installed capacity went up by 18.6% to a net value of 24. 000 MWe at the end of the year. The mean availability period has been close to the hitherto best value of 6000 h/a. The share of nuclear energy in total electricity generation in the EC rose by 0.5% to 10.5%. (orig.) [de

and alanine (EC. 2.6.1.2) transaminases, and alkaline phosphatase

African Journals Online (AJOL)

The activities of aspartate (E.C. 2.6.1.1) and alanine (E.C. 2.6.1.2) transaminases (AST and ALT, respectively), and alkaline phosphatase (ALP) (E.C. 3.1.3.1) were determined in erythrocytes obtained from 20 HbAA, 15 HbAS and 12 HbSS human subjects. The results showed that the three enzymes had different levels of ...

Neutron Stars and NuSTAR

Science.gov (United States)

Bhalerao, Varun

2012-05-01

My thesis centers around the study of neutron stars, especially those in massive binary systems. To this end, it has two distinct components: the observational study of neutron stars in massive binaries with a goal of measuring neutron star masses and participation in NuSTAR, the first imaging hard X-ray mission, one that is extremely well suited to the study of massive binaries and compact objects in our Galaxy. The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing high energy X-ray telescope to orbit. NuSTAR has an order-of-magnitude better angular resolution and has two orders of magnitude higher sensitivity than any currently orbiting hard X-ray telescope. I worked to develop, calibrate, and test CdZnTe detectors for NuSTAR. I describe the CdZnTe detectors in comprehensive detail here - from readout procedures to data analysis. Detailed calibration of detectors is necessary for analyzing astrophysical source data obtained by the NuSTAR. I discuss the design and implementation of an automated setup for calibrating flight detectors, followed by calibration procedures and results. Neutron stars are an excellent probe of fundamental physics. The maximum mass of a neutron star can put stringent constraints on the equation of state of matter at extreme pressures and densities. From an astrophysical perspective, there are several open questions in our understanding of neutron stars. What are the birth masses of neutron stars? How do they change in binary evolution? Are there multiple mechanisms for the formation of neutron stars? Measuring masses of neutron stars helps answer these questions. Neutron stars in high-mass X-ray binaries have masses close to their birth mass, providing an opportunity to disentangle the role of "nature" and "nurture" in the observed mass distributions. In 2006, masses had been measured for only six such objects, but this small sample showed the greatest diversity in masses

High-molecular weight star conjugates containing docetaxel with high anti-tumor activity and low systemic toxicity in vivo

Czech Academy of Sciences Publication Activity Database

Etrych, Tomáš; Strohalm, Jiří; Šírová, Milada; Tomalová, Barbora; Rossmann, Pavel; Říhová, Blanka; Ulbrich, Karel; Kovář, Marek

2015-01-01

Roč. 6, č. 1 (2015), s. 160-170 ISSN 1759-9954 R&D Projects: GA ČR GAP301/11/0325; GA ČR GCP207/12/J030; GA MŠk(CZ) EE2.3.20.0055 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : star polymer * HPMA copolymers * docetaxel Subject RIV: CD - Macromolecular Chemistry ; EC - Immunology (MBU-M) Impact factor: 5.687, year: 2015

Energy conservation in the EC glass industry

Energy Technology Data Exchange (ETDEWEB)

Waal, H. de [TNO Institute of Applied Physics, Delft (Netherlands)

1994-12-31

The data presented in this survey are based mainly on a recent study, performed by the Energy Technology Support Unit ETSU. Harwell Laboratory, United Kingdom, in the context of the EC-Thermie programme. Also, use has been made of a paper `Glass Manufacture, energy and CO{sub 2}-emissions`, presented by G.J. Copley of the British Glass Manufacturers Confederation, Sheffield, United Kingdom, presented at the Thermie Seminar in Wiesbaden, 1992. A third source of information has been the data collected by the CPIV, the European Glass Manufacturers Federation on the present and future economic situation of the EC Glass Industry. (orig.)

Canada files WTO complaint against EC.

Science.gov (United States)

2000-01-01

In December 1998, Canada filed a complaint alleging that the European Communities (EC) had adopted regulations that amounted to a scheme to extend patent terms, limited to pharmaceutical and agricultural chemical products.

NASA FACTS: E. coli AntiMicrobial Satellite (EcAMSat)

Science.gov (United States)

Spremo, Stevan; Cappuccio, Gelsomina; Tomko, David

2013-01-01

The E. coli AntiMicrobial Satellite(EcAMSat) mission will investigate space microgravity affects on the antibiotic resistance of E. coli, a bacterial pathogen responsible for urinary tract infection in humans and animals. EcAMSat is being developed through a partnership between NASAs Ames Research Center and the Stanford University School of Medicine. Dr. A.C. Matin is the Stanford University Principal Investigator. EcAMSat will investigate spaceflight effects on bacterial antibiotic resistance and its genetic basis. Bacterial antibiotic resistance may pose a danger to astronauts in microgravity, where the immune response is weakened. Scientists believe that the results of this experiment could help design effective countermeasures to protect astronauts health during long duration human space missions.

Accelerator-Driven Systems - the iThEC strategy

International Nuclear Information System (INIS)

Revol, Jean-Pierre

2015-01-01

The International Thorium Energy Committee (iThEC) created in Geneva in 2012 is concerned about the energetic future of our society, which is totally organized on the basis of a fossil fuel economy. This has to change because of obvious geopolitical reasons, because of the impact this economy has on the environment, and because of the rather short time on the human time scale, it will take for fossil fuels to run out. One of the main goals of iThEC is to work on reversing the current negative perception of nuclear energy in Europe, which is the main hurdle to a more serious R and D effort in this field. iThEC provides better information to the public on thorium possibilities, supports thorium ADS technology developments, any R and D regarding thorium, and actively engages the scientific, political and business leadership on the subject

Effect of Dursban 480 EC (chlorpyrifos) and Talstar 10 EC (bifenthrin) on the physiological and genetic diversity of microorganisms in soil.

Science.gov (United States)

Medo, Juraj; Maková, Jana; Kovácsová, Silvia; Majerčíková, Kamila; Javoreková, Soňa

2015-01-01

This investigation was undertaken to determine the impact of the insecticides Dursban 480 EC (with organophosphate compound chlorpyrifos as the active ingredient) and Talstar 10 EC (with pyrethroid bifenthrin as the active ingredient) on the respiration activity and microbial diversity in a sandy loam luvisol soil. The insecticides were applied in two doses: the maximum recommended dose for field application (15 mg kg(-1) for Dursban 480 EC and 6 mg kg(-1) for Talstar 10 EC) and a 100-fold higher dose for extrapolation of their effect. Bacterial and fungal genetic diversity was analysed in soil samples using PCR DGGE and the functional diversity (catabolic potential) was studied using BIOLOG EcoPlates at 1, 3, 7, 14, 28, 56 and 112 days after insecticide application. Five bacterial groups (α, β, γ proteobacteria, firmibacteria and actinomycetes) and five groups of fungi or fungus-like microorganisms (Ascomycota, Basidiomycota, Chytridiomycota, Oomycota and Zygomycota) were analysed using specific primer sets. This approach provides high resolution of the analysis covering majority of microorganisms in the soil. Only the high-dose Dursban 480 EC significantly changed the community of microorganisms. We observed its negative effect on α- and γ-proteobacteria, as the number of OTUs (operational taxonomic units) decreased until the end of incubation. In the β-proteobacteria group, initial increase of OTUs was followed by strong decrease. Diversity in the firmibacteria, actinomycetes and Zygomycota groups was minimally disturbed by the insecticide application. Dursban 480 EC, however, both positively and negatively affected certain species. Among negatively affected species Sphingomonas, Flavobacterium or Penicillium were detected, but Achromobacter, Luteibacter or Aspergillus were supported by applied insecticide. The analysis of BIOLOG plates using AWCD values indicated a significant increase in metabolic potential of microorganisms in the soil after the high

Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

Energy Technology Data Exchange (ETDEWEB)

Theodorakis, P E [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Avgeropoulos, A [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Freire, J J [Departamento de Ciencias y Tecnicas FisicoquImicas, Universidad Nacional de Educacion a Distancia, Facultad de Ciencias, Senda del Rey 9, 28040 Madrid (Spain); Kosmas, M [Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Vlahos, C [Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece)

2007-11-21

The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results.

Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

Science.gov (United States)

Theodorakis, P. E.; Avgeropoulos, A.; Freire, J. J.; Kosmas, M.; Vlahos, C.

2007-11-01

The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results.

Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

International Nuclear Information System (INIS)

Theodorakis, P E; Avgeropoulos, A; Freire, J J; Kosmas, M; Vlahos, C

2007-01-01

The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results

Nuclear power in the EC

International Nuclear Information System (INIS)

Charrault, J.C.

1991-01-01

Nuclear power accounts for some 35% of electricity production in the European Community (EC). Using a mathematical analysis, based on different scenarios, i.e. low/high electricity demand and nuclear moratorium/revival, various demand forecasts are made. A pragmatic approach, considering conventional power generation pollution problems, forecasts a revival of nuclear power

Mathematical modeling improves EC50 estimations from classical dose-response curves.

Science.gov (United States)

Nyman, Elin; Lindgren, Isa; Lövfors, William; Lundengård, Karin; Cervin, Ida; Sjöström, Theresia Arbring; Altimiras, Jordi; Cedersund, Gunnar

2015-03-01

The β-adrenergic response is impaired in failing hearts. When studying β-adrenergic function in vitro, the half-maximal effective concentration (EC50 ) is an important measure of ligand response. We previously measured the in vitro contraction force response of chicken heart tissue to increasing concentrations of adrenaline, and observed a decreasing response at high concentrations. The classical interpretation of such data is to assume a maximal response before the decrease, and to fit a sigmoid curve to the remaining data to determine EC50 . Instead, we have applied a mathematical modeling approach to interpret the full dose-response curve in a new way. The developed model predicts a non-steady-state caused by a short resting time between increased concentrations of agonist, which affect the dose-response characterization. Therefore, an improved estimate of EC50 may be calculated using steady-state simulations of the model. The model-based estimation of EC50 is further refined using additional time-resolved data to decrease the uncertainty of the prediction. The resulting model-based EC50 (180-525 nm) is higher than the classically interpreted EC50 (46-191 nm). Mathematical modeling thus makes it possible to re-interpret previously obtained datasets, and to make accurate estimates of EC50 even when steady-state measurements are not experimentally feasible. The mathematical models described here have been submitted to the JWS Online Cellular Systems Modelling Database, and may be accessed at http://jjj.bio.vu.nl/database/nyman. © 2015 FEBS.

ST ECS error handling and detector safety

CERN Document Server

Esperante Pereira, D

2010-01-01

This note describes the automatic operation sequences that the ECS implements in order to operate the ST detector in a safe and reliable way. First, the start-up sequences to set the detector in a well known state are described. In addition the possible ST detector states based on the status of the different detector elements will be defined. The states are of crucial interest for the safe operation of the detector when the LHC beam is ready. Besides, the ECS automatic actions taken in case of abnormal status of any of the detector elements are reported. Next, the operational alarm ranges and the error recovery mechanisms are mentioned.

EC Transmission Line Risk Identification and Analysis

Energy Technology Data Exchange (ETDEWEB)

Bigelow, Tim S [ORNL

2012-04-01

The purpose of this document is to assist in evaluating and planning for the cost, schedule, and technical project risks associated with the delivery and operation of the EC (Electron cyclotron) transmission line system. In general, the major risks that are anticipated to be encountered during the project delivery phase associated with the implementation of the Procurement Arrangement for the EC transmission line system are associated with: (1) Undefined or changing requirements (e.g., functional or regulatory requirements) (2) Underperformance of prototype, first unit, or production components during testing (3) Unavailability of qualified vendors for critical components Technical risks associated with the design and operation of the system are also identified.

EcPV2 DNA in equine genital squamous cell carcinomas and normal genital mucosa.

Science.gov (United States)

Bogaert, Lies; Willemsen, Anouk; Vanderstraeten, Eva; Bracho, Maria A; De Baere, Cindy; Bravo, Ignacio G; Martens, Ann

2012-07-06

Squamous cell carcinoma (SCC) represents the most common genital malignant tumor in horses. Similar to humans, papillomaviruses (PVs) have been proposed as etiological agents and recently Equine papillomavirus type 2 (EcPV2) has been identified in a subset of genital SCCs. The goals of this study were (1) to determine the prevalence of EcPV2 DNA in tissue samples from equine genital SCCs, penile intraepithelial neoplasia (PIN) and penile papillomas, using EcPV2-specific PCR, (2) to examine the prevalence of latent EcPV2 infection in healthy genital mucosa and (3) to determine genetic variability within EcPV2 and to disentangle phylogenetic relationships of EcPV2 among PVs. EcPV2 DNA was detected in all but one penile SCC (15/16), in all PIN lesions (8/8) and penile papillomas (4/4). Additionally, EcPV2 DNA was demonstrated in one of two metastasized lymph nodes, one contact metastasis in the mouth, two vaginal and one anal lesion. In healthy horses, EcPV2 DNA was detected in 10% (4/39) of penile swabs but in none of vulvovaginal swabs (0/20). This study confirms the presence of EcPV2 DNA in equine genital SCCs and shows its involvement in anal lesions, a lymph node and contact metastases. Latent EcPV2 presence was also shown in normal male genital mucosa. We found that different EcPV2 variants cocirculate among horses and that EcPV2 is related to the Delta+Zeta PVs and is only a very distant relative of high-risk human PVs causing genital cancer. Thus, similar viral tropism and similar malignant outcome of the infection do not imply close evolutionary relationship. Copyright © 2012 Elsevier B.V. All rights reserved.

The EC6 - an enhanced mid-sized reactor with fuel cycle applications

International Nuclear Information System (INIS)

Soulard, M.; Yu, S.; Hopwood, J.; Hastings, I.J.

2011-01-01

Atomic Energy of Canada Limited (AECL) has two CANDU reactor products matched to markets: the Enhanced CANDU 6 (EC6), a modern 700 MWe-class design, and the Advanced CANDU Reactor (ACR-1000), a 1200 MWe-class Gen III+ design. Both reactor types are designed to meet both market-, and customer-driven needs; the ACR-1000 design is 90% complete and market-ready. The EC6 incorporates the CANDU 6's well-proven features, and adds enhancements that make the reactor even safer and easier to operate. The EC6 is the only mid-sized reactor with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. The EC6 has domestic and offshore market pull and is the current focus of AECL's development program; market interest in the ACR-1000 is anticipated in the longer term. Some of the key features incorporated into the EC6 include upgrading containment and seismic capability to meet modern standards, shortening the overall project schedule, addressing obsolescence issues, optimizing maintenance outages and incorporating lessons learnt through feedback obtained from the operating plants. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. The first deployment of the EC6 is anticipated in Canada; off-shore markets are also being pursued. The EC6 burns natural uranium as standard. But, high neutron economy, on-power refuelling, a simple fuel bundle, and the fundamental CANDU fuel channel design provide the EC6 with the flexibility to accommodate a range of advanced fuels. (author)

ICECAP: an integrated, general-purpose, automation-assisted IC50/EC50 assay platform.

Science.gov (United States)

Li, Ming; Chou, Judy; King, Kristopher W; Jing, Jing; Wei, Dong; Yang, Liyu

2015-02-01

IC50 and EC50 values are commonly used to evaluate drug potency. Mass spectrometry (MS)-centric bioanalytical and biomarker labs are now conducting IC50/EC50 assays, which, if done manually, are tedious and error-prone. Existing bioanalytical sample preparation automation systems cannot meet IC50/EC50 assay throughput demand. A general-purpose, automation-assisted IC50/EC50 assay platform was developed to automate the calculations of spiking solutions and the matrix solutions preparation scheme, the actual spiking and matrix solutions preparations, as well as the flexible sample extraction procedures after incubation. In addition, the platform also automates the data extraction, nonlinear regression curve fitting, computation of IC50/EC50 values, graphing, and reporting. The automation-assisted IC50/EC50 assay platform can process the whole class of assays of varying assay conditions. In each run, the system can handle up to 32 compounds and up to 10 concentration levels per compound, and it greatly improves IC50/EC50 assay experimental productivity and data processing efficiency. © 2014 Society for Laboratory Automation and Screening.

Neutron stars

International Nuclear Information System (INIS)

Irvine, J.M.

1978-01-01

The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

Lymphocyte adhesion to endothelial cell (EC) is stimulated by phorbol esters

International Nuclear Information System (INIS)

Haskard, D.; Cavender, D.; Ziff, M.

1986-01-01

The effect of phorbol esters on T cell adhesion to EC has been studied. The phorbol esters 12-0-tetradecanoyl-phorbol-13-acetate and 4-beta-phorbol-12-13-dibutyrate, but not the biologically inert 4-0-methyl-phorbol-12-13-didecanoate strongly increased the binding of 51 Cr-labeled T cells to human umbilical vein EC monolayers in microtiter wells. Increase in binding was observed at 0.3 ng/ml with maximal enhancement at 50 ng/ml. Both unstimulated and phorbol ester activated T cells displayed a substantially greater binding affinity for EC than for fibroblasts or plastic. Binding enhancement occurred within one minute, with maximal increase after 15 min. Preincubation studies showed that binding enhancement was entirely attributable to an effect on T cells, with no action on EC. Additive binding enhancement was seen when phorbol esters and reagents that increase adhesion by actions on EC (LPS, IL-1 and IFN-γ) were used together. Increase in adhesion of activated T lymphocytes to EC may explain the greater emigration of activated T cells than small resting T cells into inflammatory foci in vivo. The rapid onset of the phorbol effect suggests that this may be an important mechanism for immediate localization of circulating T cells in the cellular immune response, activated, perhaps, at the endothelial blood-tissue interface

On the practical exploitability of dual EC in TLS implementations

NARCIS (Netherlands)

Checkoway, S.; Fredrikson, M.; Niederhagen, R.F.; Everspaugh, A.; Green, M.; Lange, T.; Ristenpart, T.; Bernstein, D.J.; Maskiewicz, J,; Shacham, H.

2014-01-01

This paper analyzes the actual cost of attacking TLS implementations that use NIST’s Dual EC pseudorandom number generator, assuming that the attacker generated the constants used in Dual EC. It has been known for several years that an attacker generating these constants and seeing a long enough

EC6 safety enhancement - including impact of Fukushima lessons learned

Energy Technology Data Exchange (ETDEWEB)

Yu, S.; Zemdegs, R.; Boyle, S.; Soulard, M., E-mail: stephen.yu@candu.com [Candu Energy Inc., Mississauga, Ontario (Canada)

2012-09-15

The Enhanced CANDU 6 (EC6) is the new Generation III CANDU reactor design that meets the most up to date regulatory requirements and customer expectations. EC6 builds on the proven high performance design inch as the Qinshan CANDU 6 units and has made improvements to safety and operational performance, and has incorporated extensive operational feedback including Fukushima. The Fukushima Dai-ichi March 11, 2011 event has demonstrated the importance of defence-in-depth considerations for beyond-design basis events, including severe accidents. The EC6 design is based on the defence-in-depth principles and provides further design features that address the lessons learned from Fukushima. (author)

First Kepler results on compact pulsators - II. KIC 010139564, a new pulsating subdwarf B (V361 Hya) star with an additional low-frequency mode

DEFF Research Database (Denmark)

Kawaler, Stephen; Reed, M.D.; Quint, A.C.

2010-01-01

We present the discovery of non-radial pulsations in a hot subdwarf B star based on 30.5 d of nearly continuous time series photometry using the Kepler spacecraft. KIC 010139564 is found to be a short-period pulsator of the V361 Hya (EC 14026) class with more than 10 independent pulsation modes...... whose periods range from 130 to 190 s. It also shows one periodicity at a period of 3165 s. If this periodicity is a high-order g-mode, then this star may be the hottest member of the hybrid DW Lyn stars. In addition to the resolved pulsation frequencies, additional periodic variations in the light...... are independent stellar oscillation modes. We find that most of the identified periodicities are indeed stable in phase and amplitude, suggesting a rotation period of 2-3 weeks for this star, but further observations are needed to confirm this suspicion....

Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50.

Science.gov (United States)

Utgikar, V P; Chen, B Y; Chaudhary, N; Tabak, H H; Haines, J R; Govind, R

2001-12-01

Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the

Neutron Star Science with the NuSTAR

Energy Technology Data Exchange (ETDEWEB)

Vogel, J. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-16

The Nuclear Spectroscopic Telescope Array (NuSTAR), launched in June 2012, helped scientists obtain for the first time a sensitive high-­energy X-­ray map of the sky with extraordinary resolution. This pioneering telescope has aided in the understanding of how stars explode and neutron stars are born. LLNL is a founding member of the NuSTAR project, with key personnel on its optics and science team. We used NuSTAR to observe and analyze the observations of different neutron star classes identified in the last decade that are still poorly understood. These studies not only help to comprehend newly discovered astrophysical phenomena and emission processes for members of the neutron star family, but also expand the utility of such observations for addressing broader questions in astrophysics and other physics disciplines. For example, neutron stars provide an excellent laboratory to study exotic and extreme phenomena, such as the equation of state of the densest matter known, the behavior of matter in extreme magnetic fields, and the effects of general relativity. At the same time, knowing their accurate populations has profound implications for understanding the life cycle of massive stars, star collapse, and overall galactic evolution.

EC environmental legislation and the European oil industry

International Nuclear Information System (INIS)

Luding, W.G.

1993-01-01

EUROPIA has 32 ordinary member companies which own and operate more than 95% of EC refining capacity, plus three associate member companies from EFTA countries. A large part of EUROPIA's efforts is devoted to environmental issues. Among its initial actions, EUROPIA developed Guiding Principles for environmental management which have been adopted by all member companies. This article can only highlight some of the key areas of EC environmental policy of interest to the oil industry. Most of the comments will refer to air pollution issues but, of course, water and ground pollution and waste are equally important subjects. (orig./HS)

Kinetic study on ligand exchange reaction between EC and 99mTc-GH

International Nuclear Information System (INIS)

Wu Chunying; Luo Shineng; Fang Ping; Huang Heyun; Xie Minhao; Meng Hong

1995-01-01

The ligand exchange reaction between EC and 99m Tc-GH and its influence factors such as concentrations of EC and pH were described. The concentration of EC has no influence on the exchange reaction rate constant, while pH is the most important influence factor. The rate constants of ligand exchange reaction at different pH values were determined. The results showed that in order to make the labelling yield of 99m Tc-EC higher than 90%, pH of the reaction must be higher than 8

O stars and Wolf-Rayet stars

International Nuclear Information System (INIS)

Conti, P.S.; Underhill, A.B.; Jordan, S.; Thomas, R.

1988-01-01

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented

O stars and Wolf-Rayet stars

Science.gov (United States)

Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart (Editor); Thomas, Richard (Editor)

1988-01-01

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented.

A robust star identification algorithm with star shortlisting

Science.gov (United States)

Mehta, Deval Samirbhai; Chen, Shoushun; Low, Kay Soon

2018-05-01

A star tracker provides the most accurate attitude solution in terms of arc seconds compared to the other existing attitude sensors. When no prior attitude information is available, it operates in "Lost-In-Space (LIS)" mode. Star pattern recognition, also known as star identification algorithm, forms the most crucial part of a star tracker in the LIS mode. Recognition reliability and speed are the two most important parameters of a star pattern recognition technique. In this paper, a novel star identification algorithm with star ID shortlisting is proposed. Firstly, the star IDs are shortlisted based on worst-case patch mismatch, and later stars are identified in the image by an initial match confirmed with a running sequential angular match technique. The proposed idea is tested on 16,200 simulated star images having magnitude uncertainty, noise stars, positional deviation, and varying size of the field of view. The proposed idea is also benchmarked with the state-of-the-art star pattern recognition techniques. Finally, the real-time performance of the proposed technique is tested on the 3104 real star images captured by a star tracker SST-20S currently mounted on a satellite. The proposed technique can achieve an identification accuracy of 98% and takes only 8.2 ms for identification on real images. Simulation and real-time results depict that the proposed technique is highly robust and achieves a high speed of identification suitable for actual space applications.

Star-Branched Polymers (Star Polymers)

KAUST Repository

Hirao, Akira

2015-09-01

The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

Deposition of HgTe by electrochemical atomic layer epitaxy (EC-ALE)

CSIR Research Space (South Africa)

Venkatasamy, V

2006-04-01

Full Text Available This paper describes the first instance of HgTe growth by electrochemical atomic layer epitaxy (EC-ALE). EC-ALE is the electrochemical analog of atomic layer epitaxy (ALE) and atomic layer deposition (ALD), all of which are based on the growth...

Analysis of ATLAS FLB-EC6 Experiment using SPACE Code

International Nuclear Information System (INIS)

Lee, Donghyuk; Kim, Yohan; Kim, Seyun

2013-01-01

The new code is named SPACE(Safety and Performance Analysis Code for Nuclear Power Plant). As a part of code validation effort, simulation of ATLAS FLB(Feedwater Line Break) experiment using SPACE code has been performed. The FLB-EC6 experiment is economizer break of a main feedwater line. The calculated results using the SPACE code are compared with those from the experiment. The ATLAS FLB-EC6 experiment, which is economizer feedwater line break, was simulated using the SPACE code. The calculated results were compared with those from the experiment. The comparisons of break flow rate and steam generator water level show good agreement with the experiment. The SPACE code is capable of predicting physical phenomena occurring during ATLAS FLB-EC6 experiment

Statistical investigation of flare stars. III. Flare stars in the general galactic star field

International Nuclear Information System (INIS)

Mirzoyan, L.V.; Ambaryan, V.V.; Garibdzhanyan, A.T.; Mirzoyan, A.L.

1989-01-01

Some questions relating to the existence of a large number of flare stars in the general star field of the Galaxy are discussed. It is shown that only a small proportion of them can be found by photographic observations, and the fraction of field flare stars among such stars found in the regions of star clusters and associations does not exceed 10%. The ratio of the numbers of flare stars of the foreground and the background for a particular system depends on its distance, reaching zero at a distance of about 500 pc. The spatial density of flare stars in the Pleiades is at least two orders of magnitude greater than in the general galactic field. A lower limit for the number of flare stars in the Galaxy is estimated at 4.2 ·10 9 , and the number of nonflare red dwarfs at 2.1·10 10 . There are grounds for believing that they were all formed in star clusters and associations

DOD Electronic Commerce (EC)/Electronic Data Interchange (EDI) in contracting report

Science.gov (United States)

1993-12-01

Use of Electronic Commerce (EC)/Electronic Data Interchange (EDI) to support Department of Defense (DoD) procurement processes has been under consideration for some time. A 1988 Deputy Secretary of Defense memo calls for maximum use of EDI, based on 10 years of DoD EDI investigation and experiments. In 1990, Defense Management Review Decision 941 stated, 'The strategic goal of DoD's current efforts is to provide the department with the capability to initiate, conduct, and maintain its external business related transactions and internal logistics, contracting, and financial activities without requiring the use of hard copy media.' The EC in Contracting PAT membership reflected a broad cross section of Military Services and Defense Agencies working on a full-time basis for 60 days. The diversity of the EC in Contracting PAT ensured that the needs and concerns of all DoD components were addressed during the creation of the report. The resultant plan, therefore, represents a comprehensive approach for implementing EC throughout the DoD.

STAR Infrastructure Database: An effort to know each other

Energy Technology Data Exchange (ETDEWEB)

Mora, J.C.; Real, Almudena [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas - CIEMAT (Spain); Vesterbacka, Pia; Outola, Iisa [STUK - Radiation and Nuclear Safety Authority (Finland); Barnett, Catherine; Beresford, Nick [Natural Environment Research Council - NERC-CEH (United Kingdom); Bradshaw, Clare [Stockholm University (Sweden); Skipperud, Lindis [Norwegian University of Life Sciences - UMB (Norway); Wilrodt, Christine; Steiner, Martin [Federal Office for Radiation Protection - BfS (Germany); Vanhoudt, Nathalie [Belgian Nuclear Research Centre SCK-CEN (Belgium); Komperoed, Mari [Norwegian Radiation Protection Authority - NRPA (Norway); Gurriaran, Rodolfo; Gilbin, Rodolphe; Hinton, Thomas [Institut de Radioprotection et de Surete Nucleaire - IRSN (France)

2014-07-01

radioecological research, - act as a resource for education, training and knowledge transfer, - highlight gaps and weaknesses where future effort could be directed related to the Strategic Research Agenda for radioecology From the information collated so far a comprehensive database has been assembled; part of which will be accessible from the STAR 'Virtual Laboratory' which will be available in 2014. We hope it will be a useful tool for researchers to search for skills and facilities, including those not normally associated with radioecology and other end-users such as the EC, IAEA, local, regional and National Authorities, media and university students. Document available in abstract form only. (authors)

Neutron star/red giant encounters in globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.

1988-01-01

The author presents a simple expression for the amount by which xsub(crit) is diminished as a star evolves xsub(crit) Rsub(crit)/R*, where Rsub(crit) is the maximum distance of closest approach between two stars for which the tidal energy is sufficient to bind the system, and R* is the radius of the star on which tides are being raised. Also it is concluded that tidal capture of giants by neutron stars resulting in binary systems is unlikely in globular clusters. However, collisions between neutron stars and red giants, or an alternative process involving tidal capture of a main-sequence star into an initially detached binary system, may result either in rapidly rotating neutron stars or in white dwarf/neutron star binaries. (author)

ECS: Efficient Communication Scheduling for Underwater Sensor Networks

Directory of Open Access Journals (Sweden)

Lu Hong

2011-03-01

Full Text Available TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs, because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.

Symbiotic stars

International Nuclear Information System (INIS)

Boyarchuk, A.A.

1975-01-01

There are some arguments that the symbiotic stars are binary, where one component is a red giant and the other component is a small hot star which is exciting a nebula. The symbiotic stars belong to the old disc population. Probably, symbiotic stars are just such an evolutionary stage for double stars as planetary nebulae for single stars. (Auth.)

A global inventory of aircraft NO{sub x} emissions (ANCAT/EC 2). A revised inventory (1996) by the ECAC/ANCAT and EC working group

Energy Technology Data Exchange (ETDEWEB)

Gardner, R M [Great Minister House, London (United Kingdom). Dept. of Transfert London

1998-12-31

Results of the ANCAT/EC 2 inventory produced by the European ANCAT/EC emissions inventory group is reported. The base year inventory has been completed and is currently being written up for report publication. The ANCAT/EC 2 inventory in the base year, 1991/92, has accounted for a total fuel burn of 132.5 Tg/yr and a NO{sub x} mass of 1.82 Tg/yr. The civil subsonic fleet average emissions index is EI NO{sub x} 13.9. The inventory has accounted for 80% of the IEA refined jet fuel total for 1992. The forecast 2015 inventory accounts for 289.4 Tg/yr fuel and 3.48 Tg/yr NO{sub x}, increases of 118% and 91% respectively. Both datasets will be reported fully in the next few months. (author) 5 refs.

A global inventory of aircraft NO{sub x} emissions (ANCAT/EC 2). A revised inventory (1996) by the ECAC/ANCAT and EC working group

Energy Technology Data Exchange (ETDEWEB)

Gardner, R.M. [Great Minister House, London (United Kingdom). Dept. of Transfert London

1997-12-31

Results of the ANCAT/EC 2 inventory produced by the European ANCAT/EC emissions inventory group is reported. The base year inventory has been completed and is currently being written up for report publication. The ANCAT/EC 2 inventory in the base year, 1991/92, has accounted for a total fuel burn of 132.5 Tg/yr and a NO{sub x} mass of 1.82 Tg/yr. The civil subsonic fleet average emissions index is EI NO{sub x} 13.9. The inventory has accounted for 80% of the IEA refined jet fuel total for 1992. The forecast 2015 inventory accounts for 289.4 Tg/yr fuel and 3.48 Tg/yr NO{sub x}, increases of 118% and 91% respectively. Both datasets will be reported fully in the next few months. (author) 5 refs.

Quark core stars, quark stars and strange stars

International Nuclear Information System (INIS)

Grassi, F.

1988-01-01

A recent one flavor quark matter equation of state is generalized to several flavors. It is shown that quarks undergo a first order phase transition. In addition, this equation of state depends on just one parameter in the two flavor case, two parameters in the three flavor case, and these parameters are constrained by phenomenology. This equation of state is then applied to the hadron-quark transition in neutron stars and the determination of quark star stability, the investigation of strange matter stability and possible strange star existence. 43 refs., 6 figs

Kinematic and spatial distributions of barium stars - are the barium stars and Am stars related?

International Nuclear Information System (INIS)

Hakkila, J.

1989-01-01

The possibility of an evolutionary link between Am stars and barium stars is considered, and an examination of previous data suggests that barium star precursors are main-sequence stars of intermediate mass, are most likely A and/or F dwarfs, and are intermediate-mass binaries with close to intermediate orbital separations. The possible role of mass transfer in the later development of Am systems is explored. Mass transfer and loss from systems with a range of masses and orbital separations may explain such statistical peculiarities of barium stars as the large dispersion in absolute magnitude, the large range of elemental abundances from star to star, and the small number of stars with large peculiar velocities. 93 refs

EC6 for Darlington - a managed-enhancements replication project

International Nuclear Information System (INIS)

Soulard, M.R.

2011-01-01

CANDU 6 design has a well-deserved reputation for lifetime performance and on-time, on-schedule construction. Candu Energy is finalizing development of an upgraded reactor product, the Enhanced CANDU 6 (EC6), which incorporates the CANDU 6's well-proven features, and adds enhancements that make the reactor even more safe and easier to operate. The EC6 is the only mid-sized reactor (700 MWe class) with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. Some of the key features incorporated into the EC6 include increasing the plant's power output, shortening the overall project schedule, addressing obsolescence issues, optimizing maintenance outages and incorporating lessons learnt through feedback obtained from the operating plants. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. An array of health monitoring equipment are also installed to foretell impending equipment problems, which can be acted upon, avoiding complications that could result in forced shutdowns. Improvements to the fire protection system and enhanced security features will further protect the assets. Containment and seismic capability are upgraded to meet modern standards. The first deployment of the EC6 is anticipated in Canada; other markets are also being pursued. The EC6 reactor is designed for a target lifetime capacity factor of 92% including 94% year-to-year and a 1% Forced Loss Rate. Since the number and duration of maintenance outages impact plant capacity factors, periodic short duration maintenance outages of less than a month once every 36 months is a key target of the EC6 reactor. This objective is achieved by automating a number of tasks such as shutdown systems testing. The majority

Translation and validation of the Dutch version of the Effective Consumer Scale (EC-17)

NARCIS (Netherlands)

ten Klooster, Peter M.; Taal, Erik; Tjin-Kam-Jet-Siemons, Liseth; Oostveen, J.C.M.; Oostveen, Johanna C.M.; Harmsen, Etelka J.; Tugwell, Peter S.; Rader, Tamara; Lyddiatt, Anne; van de Laar, Mart A F J

2013-01-01

PURPOSE: The Effective Consumer Scale (EC-17) measures the skills of musculoskeletal patients in managing their own healthcare. The objectives of this study were to translate the EC-17 into Dutch and to further evaluate its psychometric properties. METHODS: The EC-17 was translated and cognitively

The representation of tropical upper tropospheric water in EC Earth V2

Energy Technology Data Exchange (ETDEWEB)

Johnston, M.S. [Chalmers University of Technology, Department of Earth and Space Sciences, Goeteburg (Sweden); Swedish Meteorological and Hydrological Institute (SMHI), Norrkoeping (Sweden); Eriksson, P.; Murtagh, D.P. [Chalmers University of Technology, Department of Earth and Space Sciences, Goeteburg (Sweden); Eliasson, S. [Luleaa University of Technology, Department of Computer Science, Electrical and Space Engineering, Kiruna (Sweden); Jones, C.G. [Swedish Meteorological and Hydrological Institute (SMHI), Norrkoeping (Sweden); Forbes, R.M. [ECMWF, Reading, Berkshire (United Kingdom)

2012-12-15

Tropical upper tropospheric humidity, clouds, and ice water content, as well as outgoing longwave radiation (OLR), are evaluated in the climate model EC Earth with the aid of satellite retrievals. The Atmospheric Infrared Sounder and Microwave Limb Sounder together provide good coverage of relative humidity. EC Earth's relative humidity is in fair agreement with these observations. CloudSat and CALIPSO data are combined to provide cloud fractions estimates throughout the altitude region considered (500-100 hPa). EC Earth is found to overestimate the degree of cloud cover above 200 hPa and underestimate it below. Precipitating and non-precipitating EC Earth ice definitions are combined to form a complete ice water content. EC Earth's ice water content is below the uncertainty range of CloudSat above 250 hPa, but can be twice as high as CloudSat's estimate in the melting layer. CERES data show that the model underestimates the impact of clouds on OLR, on average with about 9 W m{sup -2}. Regionally, EC Earth's outgoing longwave radiation can be {proportional_to}20 W m{sup -2} higher than the observation. A comparison to ERA-Interim provides further perspectives on the model's performance. Limitations of the satellite observations are emphasised and their uncertainties are, throughout, considered in the analysis. Evaluating multiple model variables in parallel is a more ambitious approach than is customary. (orig.)

Egg cell-secreted EC1 triggers sperm cell activation during double fertilization.

Science.gov (United States)

Sprunck, Stefanie; Rademacher, Svenja; Vogler, Frank; Gheyselinck, Jacqueline; Grossniklaus, Ueli; Dresselhaus, Thomas

2012-11-23

Double fertilization is the defining characteristic of flowering plants. However, the molecular mechanisms regulating the fusion of one sperm with the egg and the second sperm with the central cell are largely unknown. We show that gamete interactions in Arabidopsis depend on small cysteine-rich EC1 (EGG CELL 1) proteins accumulating in storage vesicles of the egg cell. Upon sperm arrival, EC1-containing vesicles are exocytosed. The sperm endomembrane system responds to exogenously applied EC1 peptides by redistributing the potential gamete fusogen HAP2/GCS1 (HAPLESS 2/GENERATIVE CELL SPECIFIC 1) to the cell surface. Furthermore, fertilization studies with ec1 quintuple mutants show that successful male-female gamete interactions are necessary to prevent multiple-sperm cell delivery. Our findings provide evidence that mutual gamete activation, regulated exocytosis, and sperm plasma membrane modifications govern flowering plant gamete interactions.

EC4IT - A Guide to European Commission Projects for CERN/IT department

CERN Document Server

Jones, R

2012-01-01

European Commission (EC) projects represent an important source of external funding for a number of activities in which IT department is involved. The EC has a set of procedures and formalities for the preparation, negotiation, execution and completion of projects that are different to those normally used at CERN. This document gives an overview of the administrative, financial, reporting and managerial steps involved in participating in an EC project.

Present status of developing petroleum-substituting energy (EC)

Science.gov (United States)

1993-03-01

The EC has had approximately 50% of its total energy demand supplied by imports from the exterior of the Community. Hence, it is getting important to develop oil-substituting renewable energy as well as to curtail the emission of carbon dioxide. In consideration of these situations, the results of investigation on the energy policy of the European Community are described. The policy comprises three courses: European Energy Charter, formation of an open European Community energy market, and environmental conservation. Particularly, concerning the reduction of carbon dioxide emission, the EC Council has decided to introduce carbon dioxide taxation so as to suppress the carbon dioxide emission in the year 2000 to the 1990 level. The arrangement for its introduction, however, encountered with difficulties because of the opposition of various countries other than the European Community and the industrial world of the European Community. Legislation of the investment promotion law for energy saving and the construction of infrastructure footing and an information network are ineffective due to the sluggish fuel price and economic recession. A plurality of EC member countries are advancing a comprehensive activity within the framework of the joint programs of research, development, and demonstration set for the renewable energy policy ensuring energy supply and environmental harmonization.

Cooperative Fuzzy Games Approach to Setting Target Levels of ECs in Quality Function Deployment

Directory of Open Access Journals (Sweden)

Zhihui Yang

2014-01-01

Full Text Available Quality function deployment (QFD can provide a means of translating customer requirements (CRs into engineering characteristics (ECs for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

Cooperative fuzzy games approach to setting target levels of ECs in quality function deployment.

Science.gov (United States)

Yang, Zhihui; Chen, Yizeng; Yin, Yunqiang

2014-01-01

Quality function deployment (QFD) can provide a means of translating customer requirements (CRs) into engineering characteristics (ECs) for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

EC-LEDS Mexico: Advancing Clean Energy Goals

Energy Technology Data Exchange (ETDEWEB)

2016-07-01

EC-LEDS works with the government of Mexico to help meet its goals of reducing greenhouse gas emissions from the energy sector. The program targets specific, highly technical areas where Mexico has indicated the program can add value and make an impact.

EC-LEDS Supports the Low-Carbon Transition

Energy Technology Data Exchange (ETDEWEB)

2016-09-01

EC-LEDS is a flagship U.S. government-led effort that assists countries to create and implement low emission development strategies, or LEDS -- development frameworks that promote sustainable social and economic development while reducing greenhouse gas emissions over the medium to long term.

A Brightness-Referenced Star Identification Algorithm for APS Star Trackers

Science.gov (United States)

Zhang, Peng; Zhao, Qile; Liu, Jingnan; Liu, Ning

2014-01-01

Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars' intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc.) the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude) show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4∼5 times that of the pyramid method and 35∼37 times that of the geometric method. PMID:25299950

Overview of the ITER EC H and CD system and its capabilities

Energy Technology Data Exchange (ETDEWEB)

Omori, T., E-mail: toshimichi.omori@iter.org [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Henderson, M.A. [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Albajar, F. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Alberti, S. [CRPP-Association EURATOM-Confederation Suisse, EPFL Ecublens, CH-1015 Lausanne (Switzerland); Baruah, U. [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382428 (India); Bigelow, T.S. [US ITER Project Office, ORNL, 055 Commerce Park, PO Box 2008, Oak Ridge, TN 37831 (United States); Beckett, B. [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Bertizzolo, R. [CRPP-Association EURATOM-Confederation Suisse, EPFL Ecublens, CH-1015 Lausanne (Switzerland); Bonicelli, T. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral-B3, E-08019 Barcelona (Spain); Bruschi, A. [Istituto di Fisica del Plasma, Association EURATOM-ENEA-CNR, Milano (Italy); Caughman, J.B. [US ITER Project Office, ORNL, 055 Commerce Park, PO Box 2008, Oak Ridge, TN 37831 (United States); Chavan, R. [CRPP-Association EURATOM-Confederation Suisse, EPFL Ecublens, CH-1015 Lausanne (Switzerland); Cirant, S. [Istituto di Fisica del Plasma, Association EURATOM-ENEA-CNR, Milano (Italy); Collazos, A. [CRPP-Association EURATOM-Confederation Suisse, EPFL Ecublens, CH-1015 Lausanne (Switzerland); Cox, D.; Darbos, C. [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Baar, M.R. de [Association EURATOM-FOM, 3430 BE Nieuwegein (Netherlands); Denisov, G. [Institute of Applied Physics, 46 Ulyanov Street, Nizhny Novgorod 603950 (Russian Federation); Farina, D. [Istituto di Fisica del Plasma, Association EURATOM-ENEA-CNR, Milano (Italy); Gandini, F. [ITER Organization, CS 90 046, 13067 St Paul Lez Durance Cedex (France)

2011-10-15

The Electron Cyclotron (EC) system for the ITER tokamak is designed to inject {>=}20 MW RF power into the plasma for Heating and Current Drive (H and CD) applications. The EC system consists of up to 26 gyrotrons (between 1 and 2 MW each), the associated power supplies, 24 transmission lines and 5 launchers. The EC system has a diverse range of applications including central heating and current drive, current profile tailoring and control of plasma magneto-hydrodynamic (MHD) instabilities such as the sawtooth and neoclassical tearing modes (NTMs). This diverse range of applications requires the launchers to be capable of depositing the EC power across nearly the entire plasma cross section. This is achieved by two types of antennas: an equatorial port launcher (capable of injecting up to 20 MW from the plasma axis to mid-radius) and four upper port launchers providing access from inside of mid radius to near the plasma edge. The equatorial launcher design is optimized for central heating, current drive and profile tailoring, while the upper launcher should provide a very focused and peaked current density profile to control the plasma instabilities. The overall EC system has been modified during the past 3 years taking into account the issues identified in the ITER design review from 2007 and 2008 as well as integrating new technologies. This paper will review the principal objectives of the EC system, modifications made during the past 2 years and how the design is compliant with the principal objectives.

Overview of the ITER EC H and CD system and its capabilities

International Nuclear Information System (INIS)

Omori, T.; Henderson, M.A.; Albajar, F.; Alberti, S.; Baruah, U.; Bigelow, T.S.; Beckett, B.; Bertizzolo, R.; Bonicelli, T.; Bruschi, A.; Caughman, J.B.; Chavan, R.; Cirant, S.; Collazos, A.; Cox, D.; Darbos, C.; Baar, M.R. de; Denisov, G.; Farina, D.; Gandini, F.

2011-01-01

The Electron Cyclotron (EC) system for the ITER tokamak is designed to inject ≥20 MW RF power into the plasma for Heating and Current Drive (H and CD) applications. The EC system consists of up to 26 gyrotrons (between 1 and 2 MW each), the associated power supplies, 24 transmission lines and 5 launchers. The EC system has a diverse range of applications including central heating and current drive, current profile tailoring and control of plasma magneto-hydrodynamic (MHD) instabilities such as the sawtooth and neoclassical tearing modes (NTMs). This diverse range of applications requires the launchers to be capable of depositing the EC power across nearly the entire plasma cross section. This is achieved by two types of antennas: an equatorial port launcher (capable of injecting up to 20 MW from the plasma axis to mid-radius) and four upper port launchers providing access from inside of mid radius to near the plasma edge. The equatorial launcher design is optimized for central heating, current drive and profile tailoring, while the upper launcher should provide a very focused and peaked current density profile to control the plasma instabilities. The overall EC system has been modified during the past 3 years taking into account the issues identified in the ITER design review from 2007 and 2008 as well as integrating new technologies. This paper will review the principal objectives of the EC system, modifications made during the past 2 years and how the design is compliant with the principal objectives.

Belle monte-carlo production on the Amazon EC2 cloud

International Nuclear Information System (INIS)

Sevior, Martin; Fifield, Tom; Katayama, Nobuhiko

2010-01-01

The Belle II experiment which aims to increase the Luminosity of the KEKB collider by a factor of 50 will search for physics beyond the Standard Model through precision measurements and the investigation of rare processes in Flavour physics. The expected data rate is comparable to a current era LHC experiment with commensurate computing needs. Incorporating commercial cloud computing, such as that provided by the Amazon Elastic Compute Cloud (EC2) into the Belle II computing model may provide a lower Total Cost of Ownership for the Belle II computing solution. To investigate this possibility, we have created a system to conduct the complete Belle Monte Carlo simulation chain on EC2 to benchmark the cost and performance of the service. This paper will describe how this was achieved in addition to the drawbacks and costs of large-scale Monte Carlo production on EC2.

Belle monte-carlo production on the Amazon EC2 cloud

Energy Technology Data Exchange (ETDEWEB)

Sevior, Martin; Fifield, Tom [University of Melbourne, School of Physics, Victoria 3010 Australia (Australia); Katayama, Nobuhiko, E-mail: msevior@gmail.co, E-mail: fifieldt@unimelb.edu.a, E-mail: nobu.katayama@kek.j [High Energy Accelerator Research Organisation (KEK), Tsukuba (Japan)

2010-04-01

The Belle II experiment which aims to increase the Luminosity of the KEKB collider by a factor of 50 will search for physics beyond the Standard Model through precision measurements and the investigation of rare processes in Flavour physics. The expected data rate is comparable to a current era LHC experiment with commensurate computing needs. Incorporating commercial cloud computing, such as that provided by the Amazon Elastic Compute Cloud (EC2) into the Belle II computing model may provide a lower Total Cost of Ownership for the Belle II computing solution. To investigate this possibility, we have created a system to conduct the complete Belle Monte Carlo simulation chain on EC2 to benchmark the cost and performance of the service. This paper will describe how this was achieved in addition to the drawbacks and costs of large-scale Monte Carlo production on EC2.

Genes and proteins of Escherichia coli (GenProtEc).

Science.gov (United States)

Riley, M; Space, D B

1996-01-01

GenProtEc is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities among E.coli proteins with PAM values, percent identity of amino acids, length of alignment and percent aligned. The database is available as a PKZip file by ftp from mbl.edu/pub/ecoli.exe. The program runs under MS-DOS on IMB-compatible machines. GenProtEc can also be accessed through the World Wide Web at URL http://mbl.edu/html/ecoli.html.

Permeation of Telone EC through protective gloves.

Science.gov (United States)

Zainal, Hanaa; Que Hee, Shane S

2005-09-30

Telone is a potent fumigant that is based on the chlorinated unsaturated hydrocarbon, 1,3-dichloropropene (1,3-DCP). It is often applied without dilution and so poses severe inhalation and air pollution threats. Urinary metabolites of 1,3-DCP have been detected after Telone skin exposure, so that preventing dermal exposure is also important. The objective of the study was to assess if nitrile and multi-layer ("laminated") gloves provide adequate protection against Telone EC formulation. To accomplish this, disposable (Safeskin) and chemically resistant (Sol-Vex) nitrile and laminated (Barrier mark and Silver Shield) glove materials were challenged by Telone EC with hexane liquid collection in an ASTM-type I-PTC-600 permeation cell. Analyses of cis- and trans-1,3-DCP in the collection fluid at specified times were performed on a moderately polar capillary column by gas chromatography-electron capture detection. Telone EC caused microholes in both nitrile materials, though the chemically protective material was degraded slower than the disposable nitrile. The laminated gloves offered limited protection. Silver Shield protected best because 1.5-2.3 mg 1,3-DCP permeated by 8 h relative to 2.5-7.6 mg for Barrier, implying about 2.5 times more protection for 8 h. Even for Silver Shield, the extent of protection was inadequate as illustrated by a risk assessment of the skin exposure situation. The normalized breakthrough times for both types of laminated gloves varied between 27 and 60 min. It is recommended that Viton gloves still be worn for protection.

Design and application of star map simulation system for star sensors

Science.gov (United States)

Wu, Feng; Shen, Weimin; Zhu, Xifang; Chen, Yuheng; Xu, Qinquan

2013-12-01

Modern star sensors are powerful to measure attitude automatically which assure a perfect performance of spacecrafts. They achieve very accurate attitudes by applying algorithms to process star maps obtained by the star camera mounted on them. Therefore, star maps play an important role in designing star cameras and developing procession algorithms. Furthermore, star maps supply significant supports to exam the performance of star sensors completely before their launch. However, it is not always convenient to supply abundant star maps by taking pictures of the sky. Thus, star map simulation with the aid of computer attracts a lot of interests by virtue of its low price and good convenience. A method to simulate star maps by programming and extending the function of the optical design program ZEMAX is proposed. The star map simulation system is established. Firstly, based on analyzing the working procedures of star sensors to measure attitudes and the basic method to design optical system by ZEMAX, the principle of simulating star sensor imaging is given out in detail. The theory about adding false stars and noises, and outputting maps is discussed and the corresponding approaches are proposed. Then, by external programming, the star map simulation program is designed and produced. Its user interference and operation are introduced. Applications of star map simulation method in evaluating optical system, star image extraction algorithm and star identification algorithm, and calibrating system errors are presented completely. It was proved that the proposed simulation method provides magnificent supports to the study on star sensors, and improves the performance of star sensors efficiently.

Regulatory competences of the EC in the energy sector; Regelungszustaendigkeiten der EG im Bereich Energie

Energy Technology Data Exchange (ETDEWEB)

Baur, J.F.; Blask, H. [Koeln Univ. (Germany). Inst. fuer das Recht der Europaeischen Gemeinschaften und Inst. fuer Energierecht

2002-09-01

In the light of necessary amendments of the Internal Electricity Market Directive and the Internal Gas Market Directive, a debate has evolved within the European Community about lawmaking powers for the energy sector. Whereas the Member States refer to the EC Treaty and deny any lawmaking powers of the EC for the energy sector, the EC defends its position that the EC should have and can derive lawmaking competence for energy policy decisions from the EC Treaty. The author reviews the situation from the legal point of view based on existing provisions and gives an outlook on a possible outcome of the ''constitutional convention'' of the EC which is to meet for discussing a revision of the EC Treaty. (orig./CB) [German] In Bezug auf die geplanten Aenderungen der Binnenmarktrichtlinien fuer Elektrizitaet und Gas werden moegliche Kompetenzen der EG im Bereich der Energiepolitik und ihre Grenzen eroertert. In einer Schlussbetrachtung werden die Ergebnisse zusammengefasst und ein kurzer Ausblick auf die Arbeit des 'Verfassungskonvents' der EU und die anstehende Vertragsrevision geworfen, in deren Rahmen die Implikation einer eigenstaendigen Spezialkompetenz im Bereich Energie erneut thematisiert werden koennte. (orig./CB)

Regular Generalized Star Star closed sets in Bitopological Spaces

OpenAIRE

K. Kannan; D. Narasimhan; K. Chandrasekhara Rao; R. Ravikumar

2011-01-01

The aim of this paper is to introduce the concepts of τ1τ2-regular generalized star star closed sets , τ1τ2-regular generalized star star open sets and study their basic properties in bitopological spaces.

The shift of energy regulatory powers under the framework of Directive 2009/72/EC

International Nuclear Information System (INIS)

Grimm, N. S.

2011-01-01

The paper examines the powers of Member States' national regulatory authorities under the framework of Directive 2009/72/EC of the European Parliament and of the Council of 13 July 2009 concerning common rules for the internal market in electricity and repealing Directive 2003/54/EC (OJEU L 176/37) and analyses the implications of framework of Directive 2009/72/EC on the national laws of the Member States, in particular on the Austrian and German constitutional, administrative and energy laws. The Introductory Part gives a historical overview of the development of national energy regulators under European energy legislation. This Part shows that the national regulatory authorities attract increased attention and that their regulatory powers are on a constant rise. In order to understand the huge impact of the framework of Directive 2009/72/EC on the regulatory regimes of the Member States, this Part briefly examines the former and current powers of the national energy regulators under Austrian and German law. Part Two analyses whether the powers conferred upon national energy regulators under the framework of Directive 2009/72/EC have been enhanced in comparison to those established under the framework of Directive 2003/54/EC. The main focus lies thereby on the propositions made by the European Commission in its Proposal for a Directive of the European Parliament and of the Council amending Directive 2003/54/EC concerning common rules for the internal market in electricity (COM (2007) 528 final, 2.1) and laid down in Directive 2009/72/EC. Part Two comes to the conclusion that the powers of the national energy regulators under the framework of Directive 2009/72/EC have indeed been enhanced in comparison to former regime of Directive 2003/54/EC. Part Three demonstrates that the enhancement of national energy regulators' powers does not benefit the Member States. On the contrary, they lose considerable powers of control over their own national energy regulators. While

Pengaruh Tingkat EC (Electrical Conductivity terhadap Pertumbuhan Tanaman Sawi (Brassica juncea L. pada Sistem Instalasi Aeroponik Vertikal

Directory of Open Access Journals (Sweden)

Pusdima Rahma Pratiwi

2015-07-01

Full Text Available Kebutuhan akan tanaman sawi semakin meningkat, sehingga diperlukan teknologi yang dapat memaksimalkan hasil serta memperbaiki teknik budidaya, salah satunya teknik budidaya aeroponik vertikal. Penelitian ini bertujuan untuk mengetahui respon pertumbuhan tanaman sawi yang terbaik terhadap pengaruh tingkat EC pada larutan nutrisi. Penelitian ini dilaksanakan di daerah Bekasi Timur dengan ketinggian 25 m di atas permukaan laut, dimulai pada bulan April 2014 sampai Juli 2014. Rancangan yang digunakan adalah Rancangan Acak Kelompok dengan 4 perlakuan yaitu A (Tingkat EC 1 mS cm-1, B (Tingkat EC 1,5 mS cm-1, C (Tingkat EC 2 mS cm-1, dan D (Tingkat EC 2,5 mS cm-1 dengan diulang sebanyak 4 kali. Hasil penelitian menunjukkan bahwa tingkat EC berpengaruh terhadap tinggi tanaman sawi pada umur 14 dan 18 hst, luas daun pada umur 26 dan 30 hst, panjang akar pada umur 30 hst, dan bobot basah pada umur 30 hst. Tingkat EC 2,5 mS cm-1 memberikan pengaruh baik terhadap bobot basah. The increasing need of mustard require technologies that can maximize result and improve cultivation, one of them is aeroponic vertical cultivation technique. This research aimed to know the best response of mustard growth on influence of nutrient EC level. This research was carried out in Bekasi Timur with altitude of 25 m above sea level, form April 2014 to July 2014. The design used was Randomized Block Design with 4 treatments that A (EC level 1 mS cm-1, B (EC level 1,5 mS cm-1, C (EC level 2 mS cm-1, and D (EC level  2,5 mS cm-1 with 4 replications. The results showed that EC level affected on plant height at 14 and 18 dap, leaf area at 26 and 30 dap, root length at 30 dap, and wet weight at the age of 30 dap. The EC level 2,5 mS cm-1had better effect on wet weight.

I-Love relations for incompressible stars and realistic stars

Science.gov (United States)

Chan, T. K.; Chan, AtMa P. O.; Leung, P. T.

2015-02-01

In spite of the diversity in the equations of state of nuclear matter, the recently discovered I-Love-Q relations [Yagi and Yunes, Science 341, 365 (2013), 10.1126/science.1236462], which relate the moment of inertia, tidal Love number (deformability), and the spin-induced quadrupole moment of compact stars, hold for various kinds of realistic neutron stars and quark stars. While the physical origin of such universality is still a current issue, the observation that the I-Love-Q relations of incompressible stars can well approximate those of realistic compact stars hints at a new direction to approach the problem. In this paper, by establishing recursive post-Minkowskian expansion for the moment of inertia and the tidal deformability of incompressible stars, we analytically derive the I-Love relation for incompressible stars and show that the so-obtained formula can be used to accurately predict the behavior of realistic compact stars from the Newtonian limit to the maximum mass limit.

Adaptation of the Emotional Contagion Scale (ECS and gender differences within the Greek cultural context

Directory of Open Access Journals (Sweden)

Damigos Dimitris

2008-08-01

Full Text Available Abstract Background The Emotional Contagion Scale (ECS is a self-report scale used to measure individual differences in susceptibility to converge towards the emotions expressed by others. The main aim of the present paper was to examine the psychometric properties of the Greek translation of the scale. Methods The Greek ECS was completed by 691 undergraduate students (312 males and 379 females. To investigate the factor structure of the ECS, principal components analysis (PCA was used. Results The results showed that a four-factor model was tenable. Regarding homogeneity, the Greek ECS version showed acceptable results for the full scale (α = 0.74 but not for all subscales. Gender differences were also identified concerning the susceptibility to emotional contagion between men and women. Women score significantly higher than men for all the different emotions described by the ECS (love, happiness, sadness except the anger emotion, where there was no significant difference. Conclusion The Greek version of the ECS showed good psychometric properties. It can be used to assess susceptibility to emotional contagion in correlation with psychopathological processes, mood and anxiety disorders primarily. The usefulness of the ECS in the fields of group psychotherapy and health psychology is also under consideration. Further investigation is needed in all these areas.

The upgrade of the DIII-D EC system using 120 GHz ITER gyrotrons

International Nuclear Information System (INIS)

Callis, R.W.; Lohr, J.; Gorelov, I.A.; Ponce, D.; Kajiwara, K.; Tooker, J.F.

2005-01-01

The planned growth in the EC system on DIII-D over the next few years requires the installation of two depressed collector gyrotrons, a high voltage power supply, two low loss transmission lines, and the required support equipment. This new DIII-D EC equipment could be made identical to the ITER EC system requirements. By building the DIII-D hardware to the ITER specifications, it will allow ITER to gain beneficial prototyping experience on a working tokamak, prior to committing to building the hardware for delivery to ITER

Revisiting the EC/CMB model for extragalactic large scale jets

Science.gov (United States)

Lucchini, M.; Tavecchio, F.; Ghisellini, G.

2017-04-01

One of the most outstanding results of the Chandra X-ray Observatory was the discovery that AGN jets are bright X-ray emitters on very large scales, up to hundreds of kpc. Of these, the powerful and beamed jets of flat-spectrum radio quasars are particularly interesting, as the X-ray emission cannot be explained by an extrapolation of the lower frequency synchrotron spectrum. Instead, the most common model invokes inverse Compton scattering of photons of the cosmic microwave background (EC/CMB) as the mechanism responsible for the high-energy emission. The EC/CMB model has recently come under criticism, particularly because it should predict a significant steady flux in the MeV-GeV band which has not been detected by the Fermi/LAT telescope for two of the best studied jets (PKS 0637-752 and 3C273). In this work, we revisit some aspects of the EC/CMB model and show that electron cooling plays an important part in shaping the spectrum. This can solve the overproduction of γ-rays by suppressing the high-energy end of the emitting particle population. Furthermore, we show that cooling in the EC/CMB model predicts a new class of extended jets that are bright in X-rays but silent in the radio and optical bands. These jets are more likely to lie at intermediate redshifts and would have been missed in all previous X-ray surveys due to selection effects.

Search for OB stars running away from young star clusters. II. The NGC 6357 star-forming region

Science.gov (United States)

Gvaramadze, V. V.; Kniazev, A. Y.; Kroupa, P.; Oh, S.

2011-11-01

Dynamical few-body encounters in the dense cores of young massive star clusters are responsible for the loss of a significant fraction of their massive stellar content. Some of the escaping (runaway) stars move through the ambient medium supersonically and can be revealed via detection of their bow shocks (visible in the infrared, optical or radio). In this paper, which is the second of a series of papers devoted to the search for OB stars running away from young ( ≲ several Myr) Galactic clusters and OB associations, we present the results of the search for bow shocks around the star-forming region NGC 6357. Using the archival data of the Midcourse Space Experiment (MSX) satellite and the Spitzer Space Telescope, and the preliminary data release of the Wide-Field Infrared Survey Explorer (WISE), we discovered seven bow shocks, whose geometry is consistent with the possibility that they are generated by stars expelled from the young (~1-2 Myr) star clusters, Pismis 24 and AH03 J1725-34.4, associated with NGC 6357. Two of the seven bow shocks are driven by the already known OB stars, HD 319881 and [N78] 34. Follow-up spectroscopy of three other bow-shock-producing stars showed that they are massive (O-type) stars as well, while the 2MASS photometry of the remaining two stars suggests that they could be B0 V stars, provided that both are located at the same distance as NGC 6357. Detection of numerous massive stars ejected from the very young clusters is consistent with the theoretical expectation that star clusters can effectively lose massive stars at the very beginning of their dynamical evolution (long before the second mechanism for production of runaway stars, based on a supernova explosion in a massive tight binary system, begins to operate) and lends strong support to the idea that probably all field OB stars have been dynamically ejected from their birth clusters. A by-product of our search for bow shocks around NGC 6357 is the detection of three circular

Do All O Stars Form in Star Clusters?

Science.gov (United States)

Weidner, C.; Gvaramadze, V. V.; Kroupa, P.; Pflamm-Altenburg, J.

The question whether or not massive stars can form in isolation or only in star clusters is of great importance for the theory of (massive) star formation as well as for the stellar initial mass function of whole galaxies (IGIMF-theory). While a seemingly easy question it is rather difficult to answer. Several physical processes (e.g. star-loss due to stellar dynamics or gas expulsion) and observational limitations (e.g. dust obscuration of young clusters, resolution) pose severe challenges to answer this question. In this contribution we will present the current arguments in favour and against the idea that all O stars form in clusters.

Austria's environmental law in comparison with the environmental law of the EC

International Nuclear Information System (INIS)

Jantscher, S.H.

1991-11-01

The thesis describes and compares the environmental legislation in Austria and the EC. A short introduction into structure and organization of EC-institutions and EC-legislation in followed by an examination of the constitutional foundations of environmental policy in Austria and the EC respectively. After the adoption for the Single European Act, the EEC-Treaty provides for objectives, orientation criteria and instruments regarding environmental protection. These provisions constitute a valid basis for environmental action. The adoption of a constitutional law does equally declare environmental protection as an objective of the state in Austria, however, its significance is regarded as rather controversial. Some provinces ('Laender') have shown a higher degree of sensitivity in their constitutions . The distribution of powers between the EC and its member stated in the field of environmental protection is of particular interests. It is shown, that the principle of subsidiarity and the safeguard-clauses leave discretion to the member states. Much will be determined by the European Court of Justice (ECJ) . Main emphasis has been placed on the description and comparison of Austria's and the EEC-environmental legislation. Environmental legislation of Austria as well as the EC is outlined sector by sector (i.e. water, air, chemicals, waste, soil, fauna and flora) and subsequently the object of a detailed comparison. Criteria, such as - preventiveness -stringency - focus, depth and comprehensiveness - clearness and legal force of the regulations have been applied. For most of the mentioned sectors it is correct to state, that Austria's legislation is more preventive, advanced, comprehensive and stringent (especially regulations related to water, waste, chemicals, also air) . However, there are particular areas (e.g. air quality objectives, noise limits for construction plants) where Austria' s legislation may well get a fresh impetus

Demonstration of sawtooth period control with EC waves in KSTAR plasma

Directory of Open Access Journals (Sweden)

Jeong J. H.

2015-01-01

Full Text Available The sawtooth period control in tokamak is important issue in recent years because the sawtooth crash can trigger TM/NTM instabilities and drive plasmas unstable. The control of sawtooth period by the modification of local current profile near the q=1 surface using ECCD has been demonstrated in a number of tokamaks [1, 2] including KSTAR. As a result, developing techniques to control the sawtooth period as a way of controlling the onset of NTM has been an important area of research in recent years [3]. In 2012 KSTAR plasma campaign, the sawtooth period control is carried out by the different deposition position of EC waves across the q=1 surface. The sawtooth period is shortened by on-axis co-ECCD (destabilization, and the stabilization of the sawtooth is also observed by off-axis co-ECCD at outside q=1 surface. In 2013 KSTAR plasma campaign, the sawtooth locking experiment with periodic forcing of 170 GHz EC wave is carried out to control the sawtooth period. The optimal target position which lengthens the sawtooth period is investigated by performing a scan of EC beam deposition position nearby q=1 surface at the toroidal magnetic field of 2.9 T and plasma current of 0.7 MA. The sawtooth locking by the modulated EC beam is successfully demonstrated as in [3-5] with the scan of modulation-frequency and duty-ratio at the low beta (βN~0.5 plasma. In this paper, the sawteeth behavior by the location of EC beam and the preliminary result of the sawtooth locking experiments in KSTAR will be presented.

Giant CP stars

International Nuclear Information System (INIS)

Loden, L.O.; Sundman, A.

1989-01-01

This study is part of an investigation of the possibility of using chemically peculiar (CP) stars to map local galactic structure. Correct luminosities of these stars are therefore crucial. CP stars are generally regarded as main-sequence or near-main-sequence objects. However, some CP stars have been classified as giants. A selection of stars, classified in literature as CP giants, are compared to normal stars in the same effective temperature interval and to ordinary 'non giant' CP stars. There is no clear confirmation of a higher luminosity for 'CP giants', than for CP stars in general. In addition, CP characteristics seem to be individual properties not repeated in a component star or other cluster members. (author). 50 refs., 5 tabs., 3 figs

Process-engineering control valves under the EC codes; Steuerventile fuer die Prozesstechnik im Geltungsbereich der EG-Richtlinien

Energy Technology Data Exchange (ETDEWEB)

Gohlke, B. [IMI Norgren Herion Fluidtronic GmbH und Co. KG, Fellbach (Germany)

2003-09-01

The European Parliament and European Council have enacted special codes in order to implement uniform conditions in all countries of the European Community. The manufacturers of technical and commercial products are obliged to adhere to these codes. Harmonized standards, which are to be used as a tool for the implementation of the codes, are embedded at another level of the overall 'European reference literature'. Two EC codes, in particular, are definitive for fluids engineering: On the one hand, the EC Machinery Code, 98/37/EC and, on the other hand, the EC Pressurized Equipment Code, 97/23/EC. These EC codes cover, inter alia, machinery and chemical process-engineering plants, and conventional power generating plants. Norgren-Herion, a manufacturer of fluid engineering components, perceived a necessity for positioning its control valves in the scope of applicability of the EC codes. This article describes experience with the EC codes from the control valve manufacturer's point of view and examines the various qualification procedures for control valves. (orig.)

Bursting star formation and the overabundance of Wolf-Rayet stars

International Nuclear Information System (INIS)

Bodigfee, G.; Deloore, C.

1985-01-01

The ratio of the number of WR-stars to their OB progenitors appears to be significantly higher in some extragalactic systems than in our Galaxy. This overabundance of Wolf-Rayet-stars can be explained as a consequence of a recent burst of star formation. It is suggested that this burst is the manifestation of a long period nonlinear oscillation in the star formation process, produced by positive feedback effects between young stars and the interstellar medium. Star burst galaxies with large numbers of WR-stars must generate gamma fluxes but due to the distance, all of them are beyond the reach of present-day detectors, except probably 30 Dor

TRIGGERED STAR FORMATION SURROUNDING WOLF-RAYET STAR HD 211853

Energy Technology Data Exchange (ETDEWEB)

Liu Tie; Wu Yuefang; Zhang Huawei [Department of Astronomy, Peking University, 100871 Beijing (China); Qin Shengli, E-mail: liutiepku@gmail.com [I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany)

2012-05-20

The environment surrounding Wolf-Rayet (W-R) star HD 211853 is studied in molecular, infrared, as well as radio, and H I emission. The molecular ring consists of well-separated cores, which have a volume density of 10{sup 3} cm{sup -3} and kinematic temperature {approx}20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From the spectral energy distribution modeling toward the young stellar objects, the sequential star formation is revealed on a large scale in space spreading from the W-R star to the molecular ring. A small-scale sequential star formation is revealed toward core 'A', which harbors a very young star cluster. Triggered star formations are thus suggested. The presence of the photodissociation region, the fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the 'collect and collapse' process functions in this region. The star-forming activities in core 'A' seem to be affected by the 'radiation-driven implosion' process.

TRIGGERED STAR FORMATION SURROUNDING WOLF-RAYET STAR HD 211853

International Nuclear Information System (INIS)

Liu Tie; Wu Yuefang; Zhang Huawei; Qin Shengli

2012-01-01

The environment surrounding Wolf-Rayet (W-R) star HD 211853 is studied in molecular, infrared, as well as radio, and H I emission. The molecular ring consists of well-separated cores, which have a volume density of 10 3 cm –3 and kinematic temperature ∼20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From the spectral energy distribution modeling toward the young stellar objects, the sequential star formation is revealed on a large scale in space spreading from the W-R star to the molecular ring. A small-scale sequential star formation is revealed toward core 'A', which harbors a very young star cluster. Triggered star formations are thus suggested. The presence of the photodissociation region, the fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the 'collect and collapse' process functions in this region. The star-forming activities in core 'A' seem to be affected by the 'radiation-driven implosion' process.

Genes and proteins of Escherichia coli K-12 (GenProtEC).

Science.gov (United States)

Riley, M

1997-01-01

GenProtEC is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities amongE.coliproteins with PAM values, percent identity of amino acids, length of alignment and percent aligned. GenProtEC can also be accessed through the World Wide Web at URL http://mbl.edu/html/ecoli.html .

Star Polymers.

Science.gov (United States)

Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

2016-06-22

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Wolf-Rayet stars

Energy Technology Data Exchange (ETDEWEB)

Sahade, J

1981-12-01

Aspects of the problems of the Wolf-Rayet stars related to their chemical composition, their evolutionary status, and their apparent dichotomy in two spectral sequences are discussed. Dogmas concerning WR stars are critically discussed, including the belief that WR stars lack hydrogen, that they are helium stars evolved from massive close binaries, and the existence of a second WR stage in which the star is a short-period single-lined binary. The relationship of WR stars with planetary nebulae is addressed, as is the membership of these stars in clusters and associations. The division of WR stars into WN and WC sequences is considered, questioning the reasonability of accounting for WR line formation in terms of abundance differences.

EC Competition law and environmental protection

Energy Technology Data Exchange (ETDEWEB)

Rantala, M.

1996-12-31

Due to the increasing attention paid on environmental protection, by the European Community, the Member States and the consumers, undertakings are forced to adjust their policies to meet the new demands posed by public authorities and the market. This has an inevitable impact on competition. No matter how acceptable the goals were, the means are to be assessed also from the competition law point of view. The objective of this study is to analyze the situations where conflicts may take place, the main sources of research being the principles of law relating to the Treaty ,the judgements of the European Court of Justice, the Commission Decisions and other official documents of the Community as well as legal literature. This study classifies the Community and Member State instruments which are used for environmental protection into four categories. These are legislative, market-based, horizontal and financial supporting instruments. Undertakings` environmental practices, which are capable of affecting competition, are examined under Articles 85 and 86 EC, some attention being paid also to Article 90 EC. The touching points of competition policy and environmental protection in such cases are scrutinized under three headings. These are the two, in this case, most relevant public instruments, ie. legislative and market-based measures, and the voluntary actions of undertakings. (42 refs.)

Enhanced CANDU 6 (EC6): a proven mid-sized reactor with fuel cycle capability

International Nuclear Information System (INIS)

Hopwood, J.; Soulard, M.; Hastings, I.J.

2011-01-01

Atomic Energy of Canada (AECL) is finalizing development of the Enhanced CANDU 6 (EC6), which incorporates the CANDU 6's well-proven features, and adds enhancements that make the reactor even more safe and easier to operate. The EC6 is the only mid-sized reactor (700 MWe class) with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. Changes are incremental and consistent with the CANDU 6 project approach. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. Containment and seismic capability are upgraded to meet modern standards. The first deployment of the EC6 is anticipated in Canada; international markets are also being pursued. AECL is performing a comprehensive review of the EC6 design in the wake of the Fukushima accident, will review lessons learned, and incorporate any necessary improvements into new build design. (author)

Enhanced CANDU 6 (EC6): a proven mid-sized reactor with fuel cycle capability

International Nuclear Information System (INIS)

Hopwood, J.; Soulard, M.; Hastings, I.J.

2011-01-01

Atomic Energy of Canada (AECL) is finalizing development of the Enhanced CANDU 6 (EC6), which incorporates the CANDU 6's well-proven features, and enhancements that make the reactor even more safe and easier to operate. The EC6 is the only mid-sized reactor (700 MWe class) with a proven pedigree that meets modern reactor expectations and regulatory standards. It is sized for smaller grids and also has outstanding fuel-cycle capability. Changes are incremental and consistent with the CANDU 6 project approach. The EC6 utilizes modern computers and a distributed control system housed in an advanced control room which, along with automated testing and on-line diagnostics, make the plant easier and safer to operate, with minimal operator intervention. Containment and seismic capability are upgraded to meet modern standards. The first deployment of the EC6 is anticipated in Canada; international markets are also being pursued. AECL is performing a comprehensive review of the EC6 design in the wake of the Fukushima accident, will review lessons learned, and incorporate any necessary improvements into new build design. (author)

StarDOM: From STAR format to XML

International Nuclear Information System (INIS)

Linge, Jens P.; Nilges, Michael; Ehrlich, Lutz

1999-01-01

StarDOM is a software package for the representation of STAR files as document object models and the conversion of STAR files into XML. This allows interactive navigation by using the Document Object Model representation of the data as well as easy access by XML query languages. As an example application, the entire BioMagResBank has been transformed into XML format. Using an XML query language, statistical queries on the collected NMR data sets can be constructed with very little effort. The BioMagResBank/XML data and the software can be obtained at http://www.nmr.embl-heidelberg.de/nmr/StarDOM/

STARS no star on Kauai

International Nuclear Information System (INIS)

Jones, M.

1993-01-01

The island of Kuai, home to the Pacific Missile Range Facility, is preparing for the first of a series of Star Wars rocket launches expected to begin early this year. The Strategic Defense Initiative plans 40 launches of the Stategic Target System (STARS) over a 10-year period. The focus of the tests appears to be weapons and sensors designed to combat multiple-warhead ICBMs, which will be banned under the START II Treaty that was signed in January. The focus of this article is to express the dubious value of testing the STARS at a time when their application will not be an anticipated problem

A Study on Partnering Mechanism in B to B EC Server for Global Supply Chain Management

Science.gov (United States)

Kaihara, Toshiya

B to B Electronic Commerce (EC) technology is now in progress and regarded as an information infrastructure for global business. As the number and diversity of EC participants grows at the agile environment, the complexity of purchasing from a vast and dynamic array of goods and services needs to be hidden from the end user. Putting the complexity into the EC system instead means providing flexible auction server for enabling commerce within different business units. Market mechanism could solve the product distribution problem in the auction server by allocating the scheduled resources according to market prices. In this paper, we propose a partnering mechanism for B to B EC with market-oriented programming that mediates amongst unspecified various companies in the trade, and demonstrate the applicability of the economic analysis to this framework after constructing a primitive EC server. The proposed mechanism facilitates sophisticated B to B EC, which conducts a Pareto optimal solution for all the participating business units in the coming agile era.

Expression of Finger Millet EcDehydrin7 in Transgenic Tobacco Confers Tolerance to Drought Stress.

Science.gov (United States)

Singh, Rajiv Kumar; Singh, Vivek Kumar; Raghavendrarao, Sanagala; Phanindra, Mullapudi Lakshmi Venkata; Venkat Raman, K; Solanke, Amolkumar U; Kumar, Polumetla Ananda; Sharma, Tilak Raj

2015-09-01

One of the critical alarming constraints for agriculture is water scarcity. In the current scenario, global warming due to climate change and unpredictable rainfall, drought is going to be a master player and possess a big threat to stagnating gene pool of staple food crops. So it is necessary to understand the mechanisms that enable the plants to cope with drought stress. In this study, effort was made to prospect the role of EcDehydrin7 protein from normalized cDNA library of drought tolerance finger millet in transgenic tobacco. Biochemical and molecular analyses of T0 transgenic plants were done for stress tolerance. Leaf disc assay, seed germination test, dehydration assay, and chlorophyll estimation showed EcDehydrin7 protein directly link to drought tolerance. Northern and qRT PCR analyses shows relatively high expression of EcDehydrin7 protein compare to wild type. T0 transgenic lines EcDehydrin7(11) and EcDehydrin7(15) shows superior expression among all lines under study. In summary, all results suggest that EcDehydrin7 protein has a remarkable role in drought tolerance and may be used for sustainable crop breeding program in other food crops.

Ecological audits under EC regulations: background and impact in practice

International Nuclear Information System (INIS)

Walther, T.

1995-01-01

There are publications discussing the practical aspects of the implementation of the EC Directive on ecological audits, but little has been published yet on the theoretical background of the directive. The contribution in hand is intended to elucidate the theoretical basis of this instrument in the context of the system of law, explains the term of ''sustainable development'' as a key term, and reveals problems encountered in the evaluation of environmental performance. This information will contribute to a better understanding of the meaning and purposes of the EC Directive, and will thus point out ways and means for direct implementation. (orig.) [de

Formation of Compact Ellipticals in the merging star cluster scenario

Science.gov (United States)

Urrutia Zapata, Fernanda Cecilia; Theory and star formation group

2018-01-01

In the last years, extended old stellar clusters have been observed. They are like globular clusters (GCs) but with larger sizes(a limit of Re=10 pc is currently seen as reasonable). These extended objects (EOs) cover a huge range of mass. Objects at the low mass end with masses comparable to normal globular clusters are called extended clusters or faint fuzzies Larsen & Brodie (2000) and objects at the high-mass end are called ultra compact dwarf galaxies (UCDs). Ultra compact dwarf galaxies are compact object with luminositys above the brigtest known GCs. UCDs are more compact than typical dwarf galaxies but with comparable luminosities. Usually, a lower mass limit of 2 × 10^6 Solar masses is applied.Fellhauer & Kroupa (2002a,b) demostrated that object like ECs, FFs and UCDs can be the remnants of the merger of star clusters complexes, this scenario is called the Merging Star Cluster Scenario. Amore concise study was performed by Bruens et al. (2009, 2011).Our work tries to explain the formation of compact elliptical(cE). These objects are a comparatively rare class of spheroidal galaxies, possessing very small Re and high central surface brightnesses (Faber 1973). cEs have the same parameters as extended objects but they are slightly larger than 100 pc and the luminosities are in the range of -11 to -12 Mag.The standard formation sceanrio of these systems proposes a galaxy origin. CEs are the result of tidal stripping and truncation of nucleated larger systems. Or they could be a natural extension of the class of elliptical galaxies to lower luminosities and smaller sizes.We want to propose a completely new formation scenario for cEs. In our project we try to model cEs in a similar way that UCDs using the merging star cluster scenario extended to much higher masses and sizes. We think that in the early Universe we might have produced sufficiently strong star bursts to form cluster complexes which merge into cEs. So far it is observationally unknown if cEs are

Studies on absorption of EC waves in assisted startup experiment on FTU

Science.gov (United States)

Granucci, G.; Ricci, D.; Farina, D.; Figini, L.; Iraji, D.; Tudisco, O.; Ramponi, G.; Bin, W.

2012-09-01

Assistance of EC wave for plasma breakdown and current ramp up is the proposed scenario for the ITER case, characterized by low toroidal electric field. The experimental results on many tokamaks clearly indicate the capabilities of the proposed scheme to have a robust breakdown in ITER. The key aspect of this technique is the EC power required, strongly related to the absorption of the wave in the initial stage of plasma formation. This aspect is generally neglected due to the diagnostics difficulties in the plasma formation phase. As a consequence a multi-pass absorption scheme is usually considered reasonable, leading to a strong absorption after many reflections on the walls. The present study exploits the high temporal and spatial resolution of the fast scanning interferometer of FTU together with the measure of residual power obtained by a sniffer probe. The absorbed EC power is calculated considering also the polarization rotation and the subsequent mode conversion after incidence on the internal wall and compared with that derived from experimental data. The resulting EC power distribution can explain differences observed between perpendicular and oblique injection results, indicating future investigations to define ITER power requirements.

Studies on absorption of EC waves in assisted startup experiment on FTU

Directory of Open Access Journals (Sweden)

Ramponi G.

2012-09-01

Full Text Available Assistance of EC wave for plasma breakdown and current ramp up is the proposed scenario for the ITER case, characterized by low toroidal electric field. The experimental results on many tokamaks clearly indicate the capabilities of the proposed scheme to have a robust breakdown in ITER. The key aspect of this technique is the EC power required, strongly related to the absorption of the wave in the initial stage of plasma formation. This aspect is generally neglected due to the diagnostics difficulties in the plasma formation phase. As a consequence a multi-pass absorption scheme is usually considered reasonable, leading to a strong absorption after many reflections on the walls. The present study exploits the high temporal and spatial resolution of the fast scanning interferometer of FTU together with the measure of residual power obtained by a sniffer probe. The absorbed EC power is calculated considering also the polarization rotation and the subsequent mode conversion after incidence on the internal wall and compared with that derived from experimental data. The resulting EC power distribution can explain differences observed between perpendicular and oblique injection results, indicating future investigations to define ITER power requirements.

77 FR 8751 - Guidance for Decommissioning Planning During Operations

Science.gov (United States)

2012-02-15

..., 40, 50, 70, and 72 [NRC-2011-0286] Guidance for Decommissioning Planning During Operations AGENCY... Guide, DG-4014, ``Decommissioning Planning During Operations'' in the Federal Register with a public... Guide DG-4014, ``Decommissioning Planning During Operations.'' This DG refers to NUREG-1757 Volume 3...

Upgrading from the Dicon Wiring Management system to IntEC at the Gentilly 2 station

International Nuclear Information System (INIS)

Theoret, P.A.

1995-01-01

The General Electric DICON Wiring Management system supplied to HQ during the construction of G2 is currently being replaced by the stand-alone version of the IntEC software developed by AECL. The reasons for replacing DICON and choosing lntEC are discussed. The different aspects of the two year DICON data conversion project are presented with the problems encountered and the means that were taken to resolve the problems. lntEC has shown our DICON data to be considerably more deficient than we had thought. This has increased the cost and the duration of the conversion process. However, correcting the errors during the conversion process provides us with much more accurate data. This should be viewed as an investment in configuration management. Many potential causes of future errors and potentially critical path delays have been removed. We have chosen to document the detailed procedures for the use of lntEC in our plant using a Windows Help File compiler. This also has been found to be extremely useful as a training tool as well as providing on-line help. The DICON data conversion into lntEC will not be completed until 1996. lntEC is not perfect. However, from what we have up to now, we are satisfied with the conviviality and efficiency of lntEC and with AECL's diligence in constantly aspiring in making it a better product. (author)

Star-forming galaxy models: Blending star formation into TREESPH

Science.gov (United States)

Mihos, J. Christopher; Hernquist, Lars

1994-01-01

We have incorporated star-formation algorithms into a hybrid N-body/smoothed particle hydrodynamics code (TREESPH) in order to describe the star forming properties of disk galaxies over timescales of a few billion years. The models employ a Schmidt law of index n approximately 1.5 to calculate star-formation rates, and explicitly include the energy and metallicity feedback into the Interstellar Medium (ISM). Modeling the newly formed stellar population is achieved through the use of hybrid SPH/young star particles which gradually convert from gaseous to collisionless particles, avoiding the computational difficulties involved in creating new particles. The models are shown to reproduce well the star-forming properties of disk galaxies, such as the morphology, rate of star formation, and evolution of the global star-formation rate and disk gas content. As an example of the technique, we model an encounter between a disk galaxy and a small companion which gives rise to a ring galaxy reminiscent of the Cartwheel (AM 0035-35). The primary galaxy in this encounter experiences two phases of star forming activity: an initial period during the expansion of the ring, and a delayed phase as shocked material in the ring falls back into the central regions.

EMACSS: Evolve Me A Cluster of StarS

Science.gov (United States)

Alexander, Poul E. R.; Gieles, Mark

2012-03-01

The star cluster evolution code Evolve Me A Cluster of StarS (EMACSS) is a simple yet physically motivated computational model that describes the evolution of some fundamental properties of star clusters in static tidal fields. The prescription is based upon the flow of energy within the cluster, which is a constant fraction of the total energy per half-mass relaxation time. According to Henon's predictions, this flow is independent of the precise mechanisms for energy production within the core, and therefore does not require a complete description of the many-body interactions therein. Dynamical theory and analytic descriptions of escape mechanisms is used to construct a series of coupled differential equations expressing the time evolution of cluster mass and radius for a cluster of equal-mass stars. These equations are numerically solved using a fourth-order Runge-Kutta integration kernel; the results were benchmarked against a data base of direct N-body simulations. EMACSS is publicly available and reproduces the N-body results to within 10 per cent accuracy for the entire post-collapse evolution of star clusters.

MoisturEC: a new R program for moisture content estimation from electrical conductivity data

Science.gov (United States)

Terry, Neil; Day-Lewis, Frederick D.; Werkema, Dale D.; Lane, John W.

2018-01-01

Noninvasive geophysical estimation of soil moisture has potential to improve understanding of flow in the unsaturated zone for problems involving agricultural management, aquifer recharge, and optimization of landfill design and operations. In principle, several geophysical techniques (e.g., electrical resistivity, electromagnetic induction, and nuclear magnetic resonance) offer insight into soil moisture, but data‐analysis tools are needed to “translate” geophysical results into estimates of soil moisture, consistent with (1) the uncertainty of this translation and (2) direct measurements of moisture. Although geostatistical frameworks exist for this purpose, straightforward and user‐friendly tools are required to fully capitalize on the potential of geophysical information for soil‐moisture estimation. Here, we present MoisturEC, a simple R program with a graphical user interface to convert measurements or images of electrical conductivity (EC) to soil moisture. Input includes EC values, point moisture estimates, and definition of either Archie parameters (based on experimental or literature values) or empirical data of moisture vs. EC. The program produces two‐ and three‐dimensional images of moisture based on available EC and direct measurements of moisture, interpolating between measurement locations using a Tikhonov regularization approach.

Barium and Tc-poor S stars: Binary masqueraders among carbon stars

OpenAIRE

Jorissen, A.; Van Eck, S.

1997-01-01

The current understanding of the origin of barium and S stars is reviewed, based on new orbital elements and binary frequencies. The following questions are addressed: (i) Is binarity a necessary condition to produce a barium star? (ii) What is the mass transfer mode (wind accretion or RLOF?) responsible for their formation? (iii) Do barium stars form as dwarfs or as giants? (iv) Do barium stars evolve into Tc-poor S stars? (v) What is the relative frequency of Tc-rich and Tc-poor S stars?

Application of the EC eco-audit regulation in the energy industry

International Nuclear Information System (INIS)

Schulz, J.

1994-01-01

The eco-audit regulation isolates the precision of goals to improve operational environmental protection for observation, particularly with a view to the industrial energy economy. It is not wise without an investigation into the possible repercussions with other EU and national regulatory laws. Keywords here are: design of a heat application regulation according to the BImSchG, discussion over the introduction of an EC CO 2 Energy tax as well as the EC guidelines on reducing CO 2 emissions (SAVE). (orig./HP) [de

Radio stars

International Nuclear Information System (INIS)

Hjellming, R.M.

1976-01-01

Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

TURBOVELOCITY STARS: KICKS RESULTING FROM THE TIDAL DISRUPTION OF SOLITARY STARS

International Nuclear Information System (INIS)

Manukian, Haik; Guillochon, James; Ramirez-Ruiz, Enrico; O'Leary, Ryan M.

2013-01-01

The centers of most known galaxies host supermassive black holes (SMBHs). In orbit around these black holes are a centrally concentrated distribution of stars, both in single and in binary systems. Occasionally, these stars are perturbed onto orbits that bring them close to the SMBH. If the star is in a binary system, the three-body interaction with the SMBH can lead to large changes in orbital energy, depositing one of the two stars on a tightly-bound orbit, and its companion into a hyperbolic orbit that may escape the galaxy. In this Letter, we show that the disruption of solitary stars can also lead to large positive increases in orbital energy. The kick velocity depends on the amount of mass the star loses at pericenter, but not on the ratio of black hole to stellar mass, and are at most the star's own escape velocity. We find that these kicks are usually too small to result in the ejection of stars from the Milky Way, but can eject the stars from the black hole's sphere of influence, reducing their probability of being disrupted again. We estimate that ∼ 10 5 stars, ∼ 1% of all stars within 10 pc of the galactic center, are likely to have had mass removed by the central black hole through tidal interaction, and speculate that these 'turbovelocity' stars will at first be redder, but eventually bluer, and always brighter than their unharassed peers.

Radio stars

International Nuclear Information System (INIS)

Hjellming, R.M.; Gibson, D.M.

1985-01-01

Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

Inactivation of the Ecs ABC transporter of Staphylococcus aureus attenuates virulence by altering composition and function of bacterial wall.

Directory of Open Access Journals (Sweden)

Ing-Marie Jonsson

2010-12-01

Full Text Available Ecs is an ATP-binding cassette (ABC transporter present in aerobic and facultative anaerobic gram-positive Firmicutes. Inactivation of Bacillus subtilis Ecs causes pleiotropic changes in the bacterial phenotype including inhibition of intramembrane proteolysis. The molecule(s transported by Ecs is (are still unknown.In this study we mutated the ecsAB operon in two Staphylococcus aureus strains, Newman and LS-1. Phenotypic and functional characterization of these Ecs deficient mutants revealed a defect in growth, increased autolysis and lysostaphin sensitivity, altered composition of cell wall proteins including the precursor form of staphylokinase and an altered bacterial surface texture. DNA microarray analysis indicated that the Ecs deficiency changed expression of the virulence factor regulator protein Rot accompanied by differential expression of membrane transport proteins, particularly ABC transporters and phosphate-specific transport systems, protein A, adhesins and capsular polysaccharide biosynthesis proteins. Virulence of the ecs mutants was studied in a mouse model of hematogenous S. aureus infection. Mice inoculated with the ecs mutant strains developed markedly milder infections than those inoculated with the wild-type strains and had consequently lower mortality, less weight loss, milder arthritis and decreased persistence of staphylococci in the kidneys. The ecs mutants had higher susceptibility to ribosomal antibiotics and plant alkaloids chelerythrine and sanguinarine.Our results show that Ecs is essential for staphylococcal virulence and antimicrobial resistance probably since the transport function of Ecs is essential for the normal structure and function of the cell wall. Thus targeting Ecs may be a new approach in combating staphylococcal infection.

Inactivation of the Ecs ABC transporter of Staphylococcus aureus attenuates virulence by altering composition and function of bacterial wall.

Science.gov (United States)

Jonsson, Ing-Marie; Juuti, Jarmo T; François, Patrice; AlMajidi, Rana; Pietiäinen, Milla; Girard, Myriam; Lindholm, Catharina; Saller, Manfred J; Driessen, Arnold J M; Kuusela, Pentti; Bokarewa, Maria; Schrenzel, Jacques; Kontinen, Vesa P

2010-12-02

Ecs is an ATP-binding cassette (ABC) transporter present in aerobic and facultative anaerobic gram-positive Firmicutes. Inactivation of Bacillus subtilis Ecs causes pleiotropic changes in the bacterial phenotype including inhibition of intramembrane proteolysis. The molecule(s) transported by Ecs is (are) still unknown. In this study we mutated the ecsAB operon in two Staphylococcus aureus strains, Newman and LS-1. Phenotypic and functional characterization of these Ecs deficient mutants revealed a defect in growth, increased autolysis and lysostaphin sensitivity, altered composition of cell wall proteins including the precursor form of staphylokinase and an altered bacterial surface texture. DNA microarray analysis indicated that the Ecs deficiency changed expression of the virulence factor regulator protein Rot accompanied by differential expression of membrane transport proteins, particularly ABC transporters and phosphate-specific transport systems, protein A, adhesins and capsular polysaccharide biosynthesis proteins. Virulence of the ecs mutants was studied in a mouse model of hematogenous S. aureus infection. Mice inoculated with the ecs mutant strains developed markedly milder infections than those inoculated with the wild-type strains and had consequently lower mortality, less weight loss, milder arthritis and decreased persistence of staphylococci in the kidneys. The ecs mutants had higher susceptibility to ribosomal antibiotics and plant alkaloids chelerythrine and sanguinarine. Our results show that Ecs is essential for staphylococcal virulence and antimicrobial resistance probably since the transport function of Ecs is essential for the normal structure and function of the cell wall. Thus targeting Ecs may be a new approach in combating staphylococcal infection.

A hybrid method for accurate star tracking using star sensor and gyros.

Science.gov (United States)

Lu, Jiazhen; Yang, Lie; Zhang, Hao

2017-10-01

Star tracking is the primary operating mode of star sensors. To improve tracking accuracy and efficiency, a hybrid method using a star sensor and gyroscopes is proposed in this study. In this method, the dynamic conditions of an aircraft are determined first by the estimated angular acceleration. Under low dynamic conditions, the star sensor is used to measure the star vector and the vector difference method is adopted to estimate the current angular velocity. Under high dynamic conditions, the angular velocity is obtained by the calibrated gyros. The star position is predicted based on the estimated angular velocity and calibrated gyros using the star vector measurements. The results of the semi-physical experiment show that this hybrid method is accurate and feasible. In contrast with the star vector difference and gyro-assisted methods, the star position prediction result of the hybrid method is verified to be more accurate in two different cases under the given random noise of the star centroid.

Star Products and Applications

OpenAIRE

Iida, Mari; Yoshioka, Akira

2010-01-01

Star products parametrized by complex matrices are defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.

Effective star tracking method based on optical flow analysis for star trackers.

Science.gov (United States)

Sun, Ting; Xing, Fei; Wang, Xiaochu; Li, Jin; Wei, Minsong; You, Zheng

2016-12-20

Benefiting from rapid development of imaging sensor technology, modern optical technology, and a high-speed computing chip, the star tracker's accuracy, dynamic performance, and update rate have been greatly improved with low power consumption and miniature size. The star tracker is currently one of the most competitive attitude measurement sensors. However, due to restrictions of the optical imaging system, difficulties still exist in moving star spot detection and star tracking when in special motion conditions. An effective star tracking method based on optical flow analysis for star trackers is proposed in this paper. Spot-based optical flow, based on a gray gradient between two adjacent star images, is analyzed to distinguish the star spot region and obtain an accurate star spot position so that the star tracking can keep continuous under high dynamic conditions. The obtained star vectors and extended Kalman filter (EKF) are then combined to conduct an angular velocity estimation to ensure region prediction of the star spot; this can be combined with the optical flow analysis result. Experiment results show that the method proposed in this paper has advantages in conditions of large angular velocity and large angular acceleration, despite the presence of noise. Higher functional density and better performance can be achieved; thus, the star tracker can be more widely applied in small satellites, remote sensing, and other complex space missions.

Usefulness of L,L-ethylenedicysteine - 99mTc complex (EC-99mTc) for the kidney investigations

International Nuclear Information System (INIS)

Surma, M.J.; Wiewiora, J.; Kapuscinksi, J.; Liniecki, J.

1992-01-01

To assess the usefulness of own EC- 99m Tc complex for the kidney function examination, the renoscintigraphy with EC- 99m Tc and clearance determinations were performed. During renoscintigraphy the kidney images were of superb quality, with overlaying organs (liver, spleen) not visualized. Renograms showed typical shapes, their TMAX and T1/2 values being insignificantly different from the obtained with other radiopharmaceuticals, used in renoscintigraphy (MAG 3 , hippuran). Very strict correlations were found between values of EC- 99m Tc and OIH- 131 I clearances (r=0.91) and excretion rate constants (r=0.92) of both radiopharmaceuticals. The correlation enabled formulation of an equation by which ERPF could be established from EC- 99m Tc clearance: ERPF OIH =1.245 x Cl EC +51.52. On the basis of this equation a lower boundary of the normal EC- 99m Tc clearance was established; it amounts to 300 ml/min/1.73 m 2 . (author). 17 refs, 5 figs, 1 tab

Formation of stars and star clusters in colliding galaxies

International Nuclear Information System (INIS)

Belles, Pierre-Emmanuel

2012-01-01

Mergers are known to be essential in the formation of large-scale structures and to have a significant role in the history of galaxy formation and evolution. Besides a morphological transformation, mergers induce important bursts of star formation. These starburst are characterised by high Star Formation Efficiencies (SFEs) and Specific Star Formation Rates, i.e., high Star Formation Rates (SFR) per unit of gas mass and high SFR per unit of stellar mass, respectively, compared to spiral galaxies. At all redshifts, starburst galaxies are outliers of the sequence of star-forming galaxies defined by spiral galaxies. We have investigated the origin of the starburst-mode of star formation, in three local interacting systems: Arp 245, Arp 105 and NGC 7252. We combined high-resolution JVLA observations of the 21-cm line, tracing the HI diffuse gas, with UV GALEX observations, tracing the young star-forming regions. We probe the local physical conditions of the Inter-Stellar Medium (ISM) for independent star-forming regions and explore the atomic-to-dense gas transformation in different environments. The SFR/HI ratio is found to be much higher in central regions, compared to outer regions, showing a higher dense gas fraction (or lower HI gas fraction) in these regions. In the outer regions of the systems, i.e., the tidal tails, where the gas phase is mostly atomic, we find SFR/HI ratios higher than in standard HI-dominated environments, i.e., outer discs of spiral galaxies and dwarf galaxies. Thus, our analysis reveals that the outer regions of mergers are characterised by high SFEs, compared to the standard mode of star formation. The observation of high dense gas fractions in interacting systems is consistent with the predictions of numerical simulations; it results from the increase of the gas turbulence during a merger. The merger is likely to affect the star-forming properties of the system at all spatial scales, from large scales, with a globally enhanced turbulence

Stars Just Got Bigger - A 300 Solar Mass Star Uncovered

Science.gov (United States)

2010-07-01

Using a combination of instruments on ESO's Very Large Telescope, astronomers have discovered the most massive stars to date, one weighing at birth more than 300 times the mass of the Sun, or twice as much as the currently accepted limit of 150 solar masses. The existence of these monsters - millions of times more luminous than the Sun, losing weight through very powerful winds - may provide an answer to the question "how massive can stars be?" A team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, has used ESO's Very Large Telescope (VLT), as well as archival data from the NASA/ESA Hubble Space Telescope, to study two young clusters of stars, NGC 3603 and RMC 136a in detail. NGC 3603 is a cosmic factory where stars form frantically from the nebula's extended clouds of gas and dust, located 22 000 light-years away from the Sun (eso1005). RMC 136a (more often known as R136) is another cluster of young, massive and hot stars, which is located inside the Tarantula Nebula, in one of our neighbouring galaxies, the Large Magellanic Cloud, 165 000 light-years away (eso0613). The team found several stars with surface temperatures over 40 000 degrees, more than seven times hotter than our Sun, and a few tens of times larger and several million times brighter. Comparisons with models imply that several of these stars were born with masses in excess of 150 solar masses. The star R136a1, found in the R136 cluster, is the most massive star ever found, with a current mass of about 265 solar masses and with a birthweight of as much as 320 times that of the Sun. In NGC 3603, the astronomers could also directly measure the masses of two stars that belong to a double star system [1], as a validation of the models used. The stars A1, B and C in this cluster have estimated masses at birth above or close to 150 solar masses. Very massive stars produce very powerful outflows. "Unlike humans, these stars are born heavy and lose weight as

The Destructive Birth of Massive Stars and Massive Star Clusters

Science.gov (United States)

Rosen, Anna; Krumholz, Mark; McKee, Christopher F.; Klein, Richard I.; Ramirez-Ruiz, Enrico

2017-01-01

Massive stars play an essential role in the Universe. They are rare, yet the energy and momentum they inject into the interstellar medium with their intense radiation fields dwarfs the contribution by their vastly more numerous low-mass cousins. Previous theoretical and observational studies have concluded that the feedback associated with massive stars' radiation fields is the dominant mechanism regulating massive star and massive star cluster (MSC) formation. Therefore detailed simulation of the formation of massive stars and MSCs, which host hundreds to thousands of massive stars, requires an accurate treatment of radiation. For this purpose, we have developed a new, highly accurate hybrid radiation algorithm that properly treats the absorption of the direct radiation field from stars and the re-emission and processing by interstellar dust. We use our new tool to perform a suite of three-dimensional radiation-hydrodynamic simulations of the formation of massive stars and MSCs. For individual massive stellar systems, we simulate the collapse of massive pre-stellar cores with laminar and turbulent initial conditions and properly resolve regions where we expect instabilities to grow. We find that mass is channeled to the massive stellar system via gravitational and Rayleigh-Taylor (RT) instabilities. For laminar initial conditions, proper treatment of the direct radiation field produces later onset of RT instability, but does not suppress it entirely provided the edges of the radiation-dominated bubbles are adequately resolved. RT instabilities arise immediately for turbulent pre-stellar cores because the initial turbulence seeds the instabilities. To model MSC formation, we simulate the collapse of a dense, turbulent, magnetized Mcl = 106 M⊙ molecular cloud. We find that the influence of the magnetic pressure and radiative feedback slows down star formation. Furthermore, we find that star formation is suppressed along dense filaments where the magnetic field is

Spatial and Temporal Variations of EC and OC Aerosol Combustion Sources in a Polluted Metropolitan Area

Science.gov (United States)

Mouteva, G.; Randerson, J. T.; Fahrni, S.; Santos, G.; Bush, S. E.; Ehleringer, J. R.; Czimczik, C. I.

2015-12-01

Anthropogenic emissions of carbonaceous aerosols are a major component of fine air particulate matter (PM2.5) in polluted metropolitan areas and in the global atmosphere. Elemental (EC) and organic carbon (OC) aerosols influence Earth's energy balance by means of direct and indirect pathways and EC has been suggested as a better indicator of public health impacts from combustion-related sources than PM mass. Quantifying the contribution of fossil fuel and biomass combustion to the EC and OC emissions and their temporal and spatial variations is critical for developing efficient legislative air pollution control measures and successful climate mitigation strategies. In this study, we used radiocarbon (14C) to separate and quantify fossil and biomass contributions to a time series of EC and OC collected at 3 locations in Salt Lake City (SLC). Aerosol samples were collected on quartz fiber filters and a modified OC/EC analyzer was used with the Swiss_4S protocol to isolate and trap the EC fraction. Together with the total carbon (TC) content of the samples, the EC was analyzed for its 14C content with accelerator mass spectrometry. The 14C of OC was derived as a mass balance difference between TC and EC. EC had an annual average fraction modern of 0.13±0.06 and did not vary significantly across seasons. OC had an annual average FM of 0.49±0.13, with the winter mean (0.43±0.11) lower than the summer mean (0.64±0.13) at the 5% significance level. While the 3 stations were chosen to represent a variety of environmental conditions within SLC, no major differences in this source partitioning were observed between stations. During winter, the major sources of air pollutants in SLC are motor vehicles and wood stove combustion and determining their relative contributions has been the subject of debate. Our results indicated that fossil fuels were the dominant source of carbonaceous aerosols during winter, contributing 87% or more of the total EC mass and 40-75% of the OC

MoisturEC: A New R Program for Moisture Content Estimation from Electrical Conductivity Data.

Science.gov (United States)

Terry, Neil; Day-Lewis, Frederick D; Werkema, Dale; Lane, John W

2018-03-06

Noninvasive geophysical estimation of soil moisture has potential to improve understanding of flow in the unsaturated zone for problems involving agricultural management, aquifer recharge, and optimization of landfill design and operations. In principle, several geophysical techniques (e.g., electrical resistivity, electromagnetic induction, and nuclear magnetic resonance) offer insight into soil moisture, but data-analysis tools are needed to "translate" geophysical results into estimates of soil moisture, consistent with (1) the uncertainty of this translation and (2) direct measurements of moisture. Although geostatistical frameworks exist for this purpose, straightforward and user-friendly tools are required to fully capitalize on the potential of geophysical information for soil-moisture estimation. Here, we present MoisturEC, a simple R program with a graphical user interface to convert measurements or images of electrical conductivity (EC) to soil moisture. Input includes EC values, point moisture estimates, and definition of either Archie parameters (based on experimental or literature values) or empirical data of moisture vs. EC. The program produces two- and three-dimensional images of moisture based on available EC and direct measurements of moisture, interpolating between measurement locations using a Tikhonov regularization approach. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

First stars X. The nature of three unevolved carbon-enhanced metal-poor stars

DEFF Research Database (Denmark)

Sivarani, T.; Beers, T.C.; Bonifacio, P.

2006-01-01

Stars: abundances, stars: population II, Galaxy: abundances, stars: AGB and post-AGB Udgivelsesdato: Nov.......Stars: abundances, stars: population II, Galaxy: abundances, stars: AGB and post-AGB Udgivelsesdato: Nov....

False star detection and isolation during star tracking based on improved chi-square tests.

Science.gov (United States)

Zhang, Hao; Niu, Yanxiong; Lu, Jiazhen; Yang, Yanqiang; Su, Guohua

2017-08-01

The star sensor is a precise attitude measurement device for a spacecraft. Star tracking is the main and key working mode for a star sensor. However, during star tracking, false stars become an inevitable interference for star sensor applications, which may result in declined measurement accuracy. A false star detection and isolation algorithm in star tracking based on improved chi-square tests is proposed in this paper. Two estimations are established based on a Kalman filter and a priori information, respectively. The false star detection is operated through adopting the global state chi-square test in a Kalman filter. The false star isolation is achieved using a local state chi-square test. Semi-physical experiments under different trajectories with various false stars are designed for verification. Experiment results show that various false stars can be detected and isolated from navigation stars during star tracking, and the attitude measurement accuracy is hardly influenced by false stars. The proposed algorithm is proved to have an excellent performance in terms of speed, stability, and robustness.

Effects of Sludge Compost on EC value of Saline Soil and Plant Height of Medicago

Science.gov (United States)

Sun, Chongyang; Zhao, Ke; Chen, Xing; Wang, Xiaohui

2017-12-01

In this study, the effects of sludge composting on the EC value of saline soil and the response to Medicago plant height were studied by planting Medicago with pots for 45 days in different proportions as sludge composting with saline soil. The results showed that the EC value of saline soil did not change obviously with the increase of fertilization ratio,which indicated that the EC value of saline soil was close to that of the original soil. The EC decreased by 31.45% at fertilization ratio of 40%. The height of Medicago reached the highest at 40% fertilization ratio, and that was close to 60% fertilization ratio, and the difference was significant with other treatments. By comprehensive analyse and compare,the optimum application rate of sludge compost was 40% under this test condition.

White Dwarf Stars

OpenAIRE

Kepler, S. O.; Romero, Alejandra Daniela; Pelisoli, Ingrid; Ourique, Gustavo

2017-01-01

White dwarf stars are the final stage of most stars, born single or in multiple systems. We discuss the identification, magnetic fields, and mass distribution for white dwarfs detected from spectra obtained by the Sloan Digital Sky Survey up to Data Release 13 in 2016, which lead to the increase in the number of spectroscopically identified white dwarf stars from 5000 to 39000. This number includes only white dwarf stars with log g >= 6.5 stars, i.e., excluding the Extremely Low Mass white dw...

THE PREVALENCE AND IMPACT OF WOLF–RAYET STARS IN EMERGING MASSIVE STAR CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Sokal, Kimberly R.; Johnson, Kelsey E.; Indebetouw, Rémy [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Massey, Philip, E-mail: krs9tb@virginia.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

2016-08-01

We investigate Wolf–Rayet (WR) stars as a source of feedback contributing to the removal of natal material in the early evolution of massive star clusters. Despite previous work suggesting that massive star clusters clear out their natal material before the massive stars evolve into the WR phase, WR stars have been detected in several emerging massive star clusters. These detections suggest that the timescale for clusters to emerge can be at least as long as the time required to produce WR stars (a few million years), and could also indicate that WR stars may be providing the tipping point in the combined feedback processes that drive a massive star cluster to emerge. We explore the potential overlap between the emerging phase and the WR phase with an observational survey to search for WR stars in emerging massive star clusters hosting WR stars. We select candidate emerging massive star clusters from known radio continuum sources with thermal emission and obtain optical spectra with the 4 m Mayall Telescope at Kitt Peak National Observatory and the 6.5 m MMT.{sup 4} We identify 21 sources with significantly detected WR signatures, which we term “emerging WR clusters.” WR features are detected in ∼50% of the radio-selected sample, and thus we find that WR stars are commonly present in currently emerging massive star clusters. The observed extinctions and ages suggest that clusters without WR detections remain embedded for longer periods of time, and may indicate that WR stars can aid, and therefore accelerate, the emergence process.

Egyptian "Star Clocks"

Science.gov (United States)

Symons, Sarah

Diagonal, transit, and Ramesside star clocks are tables of astronomical information occasionally found in ancient Egyptian temples, tombs, and papyri. The tables represent the motions of selected stars (decans and hour stars) throughout the Egyptian civil year. Analysis of star clocks leads to greater understanding of ancient Egyptian constellations, ritual astronomical activities, observational practices, and pharaonic chronology.

GPM GROUND VALIDATION ENVIRONMENT CANADA (EC) RADIOSONDE GCPEX V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation Environment Canada (EC) Radiosonde GCPEx dataset provides measurements of pressure, temperature, humidity, and winds collected by Vaisala...

Symbiotic stars

International Nuclear Information System (INIS)

Kafatos, M.; Michalitsianos, A.G.

1984-01-01

Among the several hundred million binary systems estimated to lie within 3000 light years of the solar system, a tiny fraction, no more than a few hundred, belong to a curious subclass whose radiation has a wavelength distribution so peculiar that it long defied explanation. Such systems radiate strongly in the visible region of the spectrum, but some of them do so even more strongly at both shorter and longer wavelengths: in the ultraviolet region and in the infrared and radio regions. This odd distribution of radiation is best explained by the pairing of a cool red giant star and an intensely hot small star that is virtually in contact with its larger companion. Such objects have become known as symbiotic stars. On photographic plate only the giant star can be discerned, but evidence for the existence of the hot companion has been supplied by satellite-born instruments capable of detecting ultraviolet radiation. The spectra of symbiotic stars indicate that the cool red giant is surrounded by a very hot ionized gas. Symbiotic stars also flared up in outbursts indicating the ejection of material in the form of a shell or a ring. Symbiotic stars may therefore represent a transitory phase in the evolution of certain types of binary systems in which there is substantial transfer of matter from the larger partner to the smaller

Star tracking method based on multiexposure imaging for intensified star trackers.

Science.gov (United States)

Yu, Wenbo; Jiang, Jie; Zhang, Guangjun

2017-07-20

The requirements for the dynamic performance of star trackers are rapidly increasing with the development of space exploration technologies. However, insufficient knowledge of the angular acceleration has largely decreased the performance of the existing star tracking methods, and star trackers may even fail to track under highly dynamic conditions. This study proposes a star tracking method based on multiexposure imaging for intensified star trackers. The accurate estimation model of the complete motion parameters, including the angular velocity and angular acceleration, is established according to the working characteristic of multiexposure imaging. The estimation of the complete motion parameters is utilized to generate the predictive star image accurately. Therefore, the correct matching and tracking between stars in the real and predictive star images can be reliably accomplished under highly dynamic conditions. Simulations with specific dynamic conditions are conducted to verify the feasibility and effectiveness of the proposed method. Experiments with real starry night sky observation are also conducted for further verification. Simulations and experiments demonstrate that the proposed method is effective and shows excellent performance under highly dynamic conditions.

B- AND A-TYPE STARS IN THE TAURUS-AURIGA STAR-FORMING REGION

International Nuclear Information System (INIS)

Mooley, Kunal; Hillenbrand, Lynne; Rebull, Luisa; Padgett, Deborah; Knapp, Gillian

2013-01-01

We describe the results of a search for early-type stars associated with the Taurus-Auriga molecular cloud complex, a diffuse nearby star-forming region noted as lacking young stars of intermediate and high mass. We investigate several sets of possible O, B, and early A spectral class members. The first is a group of stars for which mid-infrared images show bright nebulae, all of which can be associated with stars of spectral-type B. The second group consists of early-type stars compiled from (1) literature listings in SIMBAD, (2) B stars with infrared excesses selected from the Spitzer Space Telescope survey of the Taurus cloud, (3) magnitude- and color-selected point sources from the Two Micron All Sky Survey, and (4) spectroscopically identified early-type stars from the Sloan Digital Sky Survey coverage of the Taurus region. We evaluated stars for membership in the Taurus-Auriga star formation region based on criteria involving: spectroscopic and parallactic distances, proper motions and radial velocities, and infrared excesses or line emission indicative of stellar youth. For selected objects, we also model the scattered and emitted radiation from reflection nebulosity and compare the results with the observed spectral energy distributions to further test the plausibility of physical association of the B stars with the Taurus cloud. This investigation newly identifies as probable Taurus members three B-type stars: HR 1445 (HD 28929), τ Tau (HD 29763), 72 Tau (HD 28149), and two A-type stars: HD 31305 and HD 26212, thus doubling the number of stars A5 or earlier associated with the Taurus clouds. Several additional early-type sources including HD 29659 and HD 283815 meet some, but not all, of the membership criteria and therefore are plausible, though not secure, members.

Life of a star

International Nuclear Information System (INIS)

Henbest, Nigel.

1988-01-01

The paper concerns the theory of stellar evolution. A description is given of:- how a star is born, main sequence stars, red giants, white dwarfs, supernovae, neutron stars and black holes. A brief explanation is given of how the death of a star as a supernova can trigger off the birth of a new generation of stars. Classification of stars and the fate of our sun, are also described. (U.K.)

Understand B-type stars

Science.gov (United States)

1982-01-01

When observations of B stars made from space are added to observations made from the ground and the total body of observational information is confronted with theoretical expectations about B stars, it is clear that nonthermal phenomena occur in the atmospheres of B stars. The nature of these phenomena and what they imply about the physical state of a B star and how a B star evolves are examined using knowledge of the spectrum of a B star as a key to obtaining an understanding of what a B star is like. Three approaches to modeling stellar structure (atmospheres) are considered, the characteristic properties of a mantle, and B stars and evolution are discussed.

On the robustness of EC-PC spike detection method for online neural recording.

Science.gov (United States)

Zhou, Yin; Wu, Tong; Rastegarnia, Amir; Guan, Cuntai; Keefer, Edward; Yang, Zhi

2014-09-30

Online spike detection is an important step to compress neural data and perform real-time neural information decoding. An unsupervised, automatic, yet robust signal processing is strongly desired, thus it can support a wide range of applications. We have developed a novel spike detection algorithm called "exponential component-polynomial component" (EC-PC) spike detection. We firstly evaluate the robustness of the EC-PC spike detector under different firing rates and SNRs. Secondly, we show that the detection Precision can be quantitatively derived without requiring additional user input parameters. We have realized the algorithm (including training) into a 0.13 μm CMOS chip, where an unsupervised, nonparametric operation has been demonstrated. Both simulated data and real data are used to evaluate the method under different firing rates (FRs), SNRs. The results show that the EC-PC spike detector is the most robust in comparison with some popular detectors. Moreover, the EC-PC detector can track changes in the background noise due to the ability to re-estimate the neural data distribution. Both real and synthesized data have been used for testing the proposed algorithm in comparison with other methods, including the absolute thresholding detector (AT), median absolute deviation detector (MAD), nonlinear energy operator detector (NEO), and continuous wavelet detector (CWD). Comparative testing results reveals that the EP-PC detection algorithm performs better than the other algorithms regardless of recording conditions. The EC-PC spike detector can be considered as an unsupervised and robust online spike detection. It is also suitable for hardware implementation. Copyright © 2014 Elsevier B.V. All rights reserved.

Damage Detection Response Characteristics of Open Circuit Resonant (SansEC) Sensors

Science.gov (United States)

Dudley, Kenneth L.; Szatkowski, George N.; Smith, Laura J.; Koppen, Sandra V.; Ely, Jay J.; Nguyen, Truong X.; Wang, Chuantong; Ticatch, Larry A.; Mielnik, John J.

2013-01-01

The capability to assess the current or future state of the health of an aircraft to improve safety, availability, and reliability while reducing maintenance costs has been a continuous goal for decades. Many companies, commercial entities, and academic institutions have become interested in Integrated Vehicle Health Management (IVHM) and a growing effort of research into "smart" vehicle sensing systems has emerged. Methods to detect damage to aircraft materials and structures have historically relied on visual inspection during pre-flight or post-flight operations by flight and ground crews. More quantitative non-destructive investigations with various instruments and sensors have traditionally been performed when the aircraft is out of operational service during major scheduled maintenance. Through the use of reliable sensors coupled with data monitoring, data mining, and data analysis techniques, the health state of a vehicle can be detected in-situ. NASA Langley Research Center (LaRC) is developing a composite aircraft skin damage detection method and system based on open circuit SansEC (Sans Electric Connection) sensor technology. Composite materials are increasingly used in modern aircraft for reducing weight, improving fuel efficiency, and enhancing the overall design, performance, and manufacturability of airborne vehicles. Materials such as fiberglass reinforced composites (FRC) and carbon-fiber-reinforced polymers (CFRP) are being used to great advantage in airframes, wings, engine nacelles, turbine blades, fairings, fuselage structures, empennage structures, control surfaces and aircraft skins. SansEC sensor technology is a new technical framework for designing, powering, and interrogating sensors to detect various types of damage in composite materials. The source cause of the in-service damage (lightning strike, impact damage, material fatigue, etc.) to the aircraft composite is not relevant. The sensor will detect damage independent of the cause

Archive of Geosample Data and Information from the U.S. Extended Continental Shelf (ECS) Project.

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Geological samples collected as part of the U.S. Extended Continental Shelf (ECS) Project are curated by the U.S. Geological Survey, a partner in the ECS Project. To...

Flare stars

International Nuclear Information System (INIS)

Nicastro, A.J.

1981-01-01

The least massive, but possibly most numerous, stars in a galaxy are the dwarf M stars. It has been observed that some of these dwarfs are characterized by a short increase in brightness. These stars are called flare stars. These flare stars release a lot of energy in a short amount of time. The process producing the eruption must be energetic. The increase in light intensity can be explained by a small area rising to a much higher temperature. Solar flares are looked at to help understand the phenomenon of stellar flares. Dwarfs that flare are observed to have strong magnetic fields. Those dwarf without the strong magnetic field do not seem to flare. It is believed that these regions of strong magnetic fields are associated with star spots. Theories on the energy that power the flares are given. Astrophysicists theorize that the driving force of a stellar flare is the detachment and collapse of a loop of magnetic flux. The mass loss due to stellar flares is discussed. It is believed that stellar flares are a significant contributor to the mass of interstellar medium in the Milky Way

By Draconis Stars

Science.gov (United States)

Bopp, Bernard W.

An optical spectroscopic survey of dK-M stars has resulted in the discovery of several new H-alpha emission objects. Available optical data suggest these stars have a level of chromospheric activity midway between active BY Dra stars and quiet dM's. These "marginal" BY Dra stars are single objects that have rotation velocities slightly higher than that of quiet field stars but below that of active flare/BY Dra objects. The marginal BY Dra stars provide us with a class of objects rotating very near a "trigger velocity" (believed to be 5 km/s) which appears to divide active flare/BY Dra stars from quiet dM's. UV data on Mg II emission fluxes and strength of transition region features such as C IV will serve to fix activity levels in the marginal objects and determine chromosphere and transition-region heating rates. Simultaneous optical magnetic field measures will be used to explore the connection between fieldstrength/filling-factor and atmospheric heating. Comparison of these data with published information on active and quiet dM stars will yield information on the character of the stellar dynamo as it makes a transition from "low" to "high" activity.

Shooting stars

International Nuclear Information System (INIS)

Maurette, M.; Hammer, C.

1985-01-01

A shooting star passage -even a star shower- can be sometimes easily seen during moonless black night. They represent the partial volatilization in earth atmosphere of meteorites or micrometeorites reduced in cosmic dusts. Everywhere on earth, these star dusts are searched to be gathered. This research made one year ago on the Greenland ice-cap is this article object; orbit gathering projects are also presented [fr

The Vixen Star Book user guide how to use the star book ten and the original star book

CERN Document Server

Chen, James

2016-01-01

This book is for anyone who owns, or is thinking of owning, a Vixen Star Book Ten telescope mount or its predecessor. A revolution in amateur astronomy has occurred in the past decade with the wide availability of high tech, computer-driven, Go-To telescopes. Vixen Optics is leading the way by offering the Star Book Ten system, with its unique star map graphics software. The Star Book Ten is the latest version of computer telescope control using star map graphics as a user interface, first introduced in the original Star Book first offered in 2003. The increasingly complicated nature of this software means that learning to optimize this program is not straightforward, and yet the resulting views when all features are correctly deployed can be phenomenal. After a short history of computerized Go-To telescopes for the consumer amateur astronomer market, Chen offers a treasury of technical information. His advice, tips, and solutions aid the user in getting the most out of the Star Book Ten system in observing s...

ESCAPE: an integrated climate model for the EC

International Nuclear Information System (INIS)

Rotmans, J.

1992-01-01

A framework has been developed for the evaluation of policy options for climate change, called ESCAPE (Evaluation of Strategies to address Climate change by Adapting to and Preventing Emissions). ESCAPE consists of a suite of linked models which enables scenarios of greenhouse gas emissions to be constructed and their impact on global and regional climate and sea level and sectors of the European economy to be assessed. Conclusions resulting from simulations with the ESCAPE 1.1 model include: the major problem of a climate change for the EC is a sea level rise; Greece, Italy, Portugal and Spain will be faced with higher costs in the agricultural sector; worldwide implementation of an EC carbon tax leads to about 12% lower worldwide CO 2 emissions; to stabilize CO 2 emissions an Ecotax of 18 dollars per barrel would be required; and in all cases the rate of global temperature increase will be above the rate of 0.1 degree C per decade for the coming 40 years. 2 figs

Business-to-business electronic commerce systems and services. Smart EC solution; Kigyoka nrenkei system solution system. Smart EC solution

Energy Technology Data Exchange (ETDEWEB)

Setoguchi, T.; Manchu, Y.; Katsumata, M. [Toshiba Corp., Tokyo (Japan)

2000-04-01

Toshiba provides a range of information technology (IT) solutions called SmartEC Solution, which includes business-to-business electronic commerce systems and services based on international standards and industrial know-how, especially our electronic data interchange (EDI) know-how as a manufacturer. These IT solutions are supplied as services covering strategy planning, system integration, and application service provider based on five types of business-to-business electronic commerce. (author)

STAR-TO-STAR IRON ABUNDANCE VARIATIONS IN RED GIANT BRANCH STARS IN THE GALACTIC GLOBULAR CLUSTER NGC 3201

International Nuclear Information System (INIS)

Simmerer, Jennifer; Ivans, Inese I.; Filler, Dan; Francois, Patrick; Charbonnel, Corinne; Monier, Richard; James, Gaël

2013-01-01

We present the metallicity as traced by the abundance of iron in the retrograde globular cluster NGC 3201, measured from high-resolution, high signal-to-noise spectra of 24 red giant branch stars. A spectroscopic analysis reveals a spread in [Fe/H] in the cluster stars at least as large as 0.4 dex. Star-to-star metallicity variations are supported both through photometry and through a detailed examination of spectra. We find no correlation between iron abundance and distance from the cluster core, as might be inferred from recent photometric studies. NGC 3201 is the lowest mass halo cluster to date to contain stars with significantly different [Fe/H] values.

Star-to-star Iron Abundance Variations in Red Giant Branch Stars in the Galactic Globular Cluster NGC 3201

Science.gov (United States)

Simmerer, Jennifer; Ivans, Inese I.; Filler, Dan; Francois, Patrick; Charbonnel, Corinne; Monier, Richard; James, Gaël

2013-02-01

We present the metallicity as traced by the abundance of iron in the retrograde globular cluster NGC 3201, measured from high-resolution, high signal-to-noise spectra of 24 red giant branch stars. A spectroscopic analysis reveals a spread in [Fe/H] in the cluster stars at least as large as 0.4 dex. Star-to-star metallicity variations are supported both through photometry and through a detailed examination of spectra. We find no correlation between iron abundance and distance from the cluster core, as might be inferred from recent photometric studies. NGC 3201 is the lowest mass halo cluster to date to contain stars with significantly different [Fe/H] values.

The first stars: CEMP-no stars and signatures of spinstars

Science.gov (United States)

Maeder, André; Meynet, Georges; Chiappini, Cristina

2015-04-01

Aims: The CEMP-no stars are "carbon-enhanced-metal-poor" stars that in principle show no evidence of s- and r-elements from neutron captures. We try to understand the origin and nucleosynthetic site of their peculiar CNO, Ne-Na, and Mg-Al abundances. Methods: We compare the observed abundances to the nucleosynthetic predictions of AGB models and of models of rotating massive stars with internal mixing and mass loss. We also analyze the different behaviors of α- and CNO-elements, as well the abundances of elements involved in the Ne-Na and Mg-Al cycles. Results: We show that CEMP-no stars exhibit products of He-burning that have gone through partial mixing and processing by the CNO cycle, producing low 12C/13C and a broad variety of [C/N] and [O/N] ratios. From a 12C/13C vs. [C/N] diagram, we conclude that neither the yields of AGB stars (in binaries or not) nor the yields of classic supernovae can fully account for the observed CNO abundances in CEMP-no stars. Better agreement is obtained once the chemical contribution by stellar winds of fast-rotating massive stars is taken into account, where partial mixing takes place, leading to various amounts of CNO being ejected. The [(C+N+O)/H] ratios of CEMP-no stars vary linearly with [Fe/H] above [Fe/H] = -4.0 indicating primary behavior by (C+N+O). Below [Fe/H] = -4.0, [(C+N+O)/H] is almost constant as a function of [Fe/H], implying very high [(C+N+O)/Fe] ratios up to 4 dex. In view of the timescales, such abundance ratios reflect more individual nucleosynthetic properties, rather than an average chemical evolution. The high [(C+N+O)/Fe] ratios (as well as the high [(C+N+O)/α-elements]) imply that stellar winds from partially mixed stars were the main source of these excesses of heavy elements now observed in CEMP-no stars. The ranges covered by the variations of [Na/Fe], [Mg/Fe], and [Al/Fe] are much broader than for the α-elements (with an atomic mass number above 24) and are comparable to the wide ranges covered

Star Cluster Structure from Hierarchical Star Formation

Science.gov (United States)

Grudic, Michael; Hopkins, Philip; Murray, Norman; Lamberts, Astrid; Guszejnov, David; Schmitz, Denise; Boylan-Kolchin, Michael

2018-01-01

Young massive star clusters (YMCs) spanning 104-108 M⊙ in mass generally have similar radial surface density profiles, with an outer power-law index typically between -2 and -3. This similarity suggests that they are shaped by scale-free physics at formation. Recent multi-physics MHD simulations of YMC formation have also produced populations of YMCs with this type of surface density profile, allowing us to narrow down the physics necessary to form a YMC with properties as observed. We show that the shallow density profiles of YMCs are a natural result of phase-space mixing that occurs as they assemble from the clumpy, hierarchically-clustered configuration imprinted by the star formation process. We develop physical intuition for this process via analytic arguments and collisionless N-body experiments, elucidating the connection between star formation physics and star cluster structure. This has implications for the early-time structure and evolution of proto-globular clusters, and prospects for simulating their formation in the FIRE cosmological zoom-in simulations.

Motion-blurred star acquisition method of the star tracker under high dynamic conditions.

Science.gov (United States)

Sun, Ting; Xing, Fei; You, Zheng; Wei, Minsong

2013-08-26

The star tracker is one of the most promising attitude measurement devices used in spacecraft due to its extremely high accuracy. However, high dynamic performance is still one of its constraints. Smearing appears, making it more difficult to distinguish the energy dispersive star point from the noise. An effective star acquisition approach for motion-blurred star image is proposed in this work. The correlation filter and mathematical morphology algorithm is combined to enhance the signal energy and evaluate slowly varying background noise. The star point can be separated from most types of noise in this manner, making extraction and recognition easier. Partial image differentiation is then utilized to obtain the motion parameters from only one image of the star tracker based on the above process. Considering the motion model, the reference window is adopted to perform centroid determination. Star acquisition results of real on-orbit star images and laboratory validation experiments demonstrate that the method described in this work is effective and the dynamic performance of the star tracker could be improved along with more identified stars and guaranteed position accuracy of the star point.

Lunar Module ECS (Environmental Control System) - Design Considerations and Failure Modes. Part 1

Science.gov (United States)

Interbartolo, Michael

2009-01-01

Design considerations and failure modes for the Lunar Module (LM) Environmental Control System (ECS) are described. An overview of the the oxygen supply and cabin pressurization, atmosphere revitalization, water management and heat transport systems are provided. Design considerations including reliability, flight instrumentation, modularization and the change to the use of batteries instead of fuel cells are discussed. A summary is provided for the LM ECS general testing regime.

Experimental Study on Performance of EC-120 Wet-mixing Modified Asphalt Cementing Materials%EC-120温拌改性沥青胶结料性能试验研究

Institute of Scientific and Technical Information of China (English)

周刚; 唐江; 谭昆华; 谭巍

2012-01-01

This paper carries out experimental study on rotational viscosity, normal performance indices and rheological properties, etc. of EC-120 organic viscosity reducing and wet-mixing modified asphalt, the experiment shows that EC-120 as an organic additive with the melting point at approximate 100 t is well compatible with asphalt and easy to prepare without problem of isolation. The experiment also shows EC-120 in wet-mixing modified asphalt can reduce high-temperature viscosity and increase medium and low-temperature viscosity of asphalt so as to decrease mixing and compacting temperature of asphalt mixtures; can reduce needle penetration and increase softening point and anti-rutting factor so as to improve high-temperature stability of asphalt remarkably; and will enable reduction of ductility, increase of fatigue factor, increase of creepage stiffness and reduction of deformation rate of wet-mixing modified asphalt, which slightly have negative influence on anti-fatigue and low-temperature cracking properties of asphalt.%对EC-120有机降粘温拌改性沥青进行旋转粘度、常规性能指标、流变特性等试验研究,试验表明,EC- 120作为一种熔点在100℃左右的有机添加剂,与沥青相容性好,制备容易,不存在离析问题.试验还表明在温拌改性沥青中,EC-120可降低沥青的高温粘度,提高中低温粘度,从而降低沥青混合料的拌和和压实温度;可降低沥青针入度,提高软化点和抗车辙因子,从而大幅改善沥青的高温稳定性;会使温拌改性沥青的延度降低,疲劳因子增大,蠕变劲度增大,变形速率减小,对沥青的抗疲劳和低温抗开裂性能略有消极影响.

Normal human serum (HS) prevents oxidant-induced lysis of cultured endothelial cells (ECs)

International Nuclear Information System (INIS)

Callahan, K.S.; Harlan, J.M.

1986-01-01

Most studies demonstrating oxidant lysis of cultured ECs are performed in serum-free media or media containing low concentrations of bovine serum. The authors found that HS protects human and bovine ECs from lysis caused by reagent H 2 O 2 or glucose/glucose oxidase (GO)-generated H 2 O 2 . EC injury was assessed by 51 Cr release, cell detachment, or trypan blue dye exclusion. Protective HS activity was dose-dependent with concentrations greater than or equal to 25% preventing lethal injury. Cytotoxicity at 24 hrs, induced by 20 mU/ml GO, was 90.1 +/- 5.2% without HS vs 1.7 +/- 4.6% with 25% HS present (20 exp). Similar protection was observed with heparinized plasma. Of note, comparable concentrations of bovine serum were devoid of protective activity. Addition of fatty acid-free albumin to the media was also without protective effect. Preliminary characterization showed HS activity was stable to 60 0 C for 30 min, non-dialyzable at 25,000 MW cutoff, and retained in delipidated serum. The HS protection was not merely due to scavenging of exogenous H 2 O 2 as A23187-induced EC lysis was also prevented by HS. Protective activity was not reproduced by purified cerruloplasmin or transferrin. In conclusion, unidentified factor(s) present in HS protect cultured ECs from oxidant-induced lysis. Since endothelium is normally exposed to 100% plasma, the authors suggest that in vitro studies of oxidant-mediated injury be performed in the presence of HS. Factor(s) in HS may play an important role in modulating oxidant-induced vascular injury in vivo

Energy production in stars

International Nuclear Information System (INIS)

Bethe, Hans.

1977-01-01

Energy in stars is released partly by gravitation, partly by nuclear reactions. For ordinary stars like our sun, nuclear reactions predominate. However, at the end of the life of a star very large amounts of energy are released by gravitational collapse; this can amount to as much as 10 times the total energy released nuclear reactions. The rotational energy of pulsars is a small remnant of the energy of gravitation. The end stage of small stars is generally a white dwarf, of heavy stars a neutron star of possibly a black hole

Stars and Flowers, Flowers and Stars

Science.gov (United States)

Minti, Hari

2012-12-01

The author, a graduated from the Bucharest University (1964), actually living and working in Israel, concerns his book to variable stars and flowers, two domains of his interest. The analogies includes double stars, eclipsing double stars, eclipses, Big Bang. The book contains 34 chapters, each of which concerns various relations between astronomy and other sciences and pseudosciences such as Psychology, Religion, Geology, Computers and Astrology (to which the author is not an adherent). A special part of the book is dedicated to archeoastronomy and ethnoastronomy, as well as to history of astronomy. Between the main points of interest of these parts: ancient sanctuaries in Sarmizegetusa (Dacia), Stone Henge(UK) and other. The last chapter of the book is dedicated to flowers. The book is richly illustrated. It is designed for a wide circle of readers.

How bright planets became dim stars: planetary speculations in John Herschel's double star astronomy.

Science.gov (United States)

Case, Stephen

2014-03-01

Previous research on the origins of double star astronomy in the early nineteenth century emphasized the role mathematical methods and instrumentation played in motivating early observations of these objects. The work of the British astronomer John Herschel, however, shows that questions regarding the physical nature of double stars were also important. In particular, an analysis of John Herschel's early work on double stars illustrates the way in which speculations regarding these objects were shaped by assumptions of the properties of stars themselves. For Herschel, a major consideration in double star astronomy was distinguishing between types of double stars. Optical doubles were useful in determining parallax while binary doubles were not. In practice, classification of a specific double star pair into one of these categories was based on the assumption that stars were of approximately the same luminosity and thus differences in relative brightness between stars were caused by difference in distances. Such assumptions, though ultimately abandoned, would lead Herschel in the 1830s to advance the possibility that the dim companion stars in certain double star pairs were not stars at all but in fact planets. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spectrophotometry of peculiar B and A stars. II. Eleven mercury-manganese stars

International Nuclear Information System (INIS)

Adelman, S.J.; Pyper, D.M.

1979-01-01

Spectrophotometry of eleven HgMn stars is presented for the optical region. As found in Paper I, the HgMn stars have systematically larger Δiota* and Δa values than the normal main sequence stars due to differences with respect to the mean continuum particularly of the lambda4464 values and the lambda5200 region, respectively. The HgMn stars exhibit a continuous range in the behavior of both the lambda4200 and lambda5200 regions between those stars that have index values larger than the appropriate criterion of presence and present definite evidence for the features to those stars with only a slight possibility of such features. The strengths of the lambda4200 and lambda5200 features appear not to be correlated. In the HgMn stars, both features may be due to differential line blocking. In the energy distribution of all eleven stars, the Balmer jump regions best fit the predictions of slightly hotter solar composition, log g=4.0, fully line blanketed model atmospheres than do the corresponding Paschen continua

Discriminating strange star mergers from neutron star mergers by gravitational-wave measurements

International Nuclear Information System (INIS)

Bauswein, A.; Oechslin, R.; Janka, H.-T.

2010-01-01

We perform three-dimensional relativistic hydrodynamical simulations of the coalescence of strange stars and explore the possibility to decide on the strange matter hypothesis by means of gravitational-wave measurements. Self-binding of strange quark matter and the generally more compact stars yield features that clearly distinguish strange star from neutron star mergers, e.g. hampering tidal disruption during the plunge of quark stars. Furthermore, instead of forming dilute halo structures around the remnant as in the case of neutron star mergers, the coalescence of strange stars results in a differentially rotating hypermassive object with a sharp surface layer surrounded by a geometrically thin, clumpy high-density strange quark matter disk. We also investigate the importance of including nonzero temperature equations of state in neutron star and strange star merger simulations. In both cases we find a crucial sensitivity of the dynamics and outcome of the coalescence to thermal effects, e.g. the outer remnant structure and the delay time of the dense remnant core to black hole collapse depend on the inclusion of nonzero temperature effects. For comparing and classifying the gravitational-wave signals, we use a number of characteristic quantities like the maximum frequency during inspiral or the dominant frequency of oscillations of the postmerger remnant. In general, these frequencies are higher for strange star mergers. Only for particular choices of the equation of state the frequencies of neutron star and strange star mergers are similar. In such cases additional features of the gravitational-wave luminosity spectrum like the ratio of energy emitted during the inspiral phase to the energy radiated away in the postmerger stage may help to discriminate coalescence events of the different types. If such characteristic quantities could be extracted from gravitational-wave signals, for instance with the upcoming gravitational-wave detectors, a decision on the

Development of EC technology in JAERI

International Nuclear Information System (INIS)

Sakamoto, Keishi; Takahashi, Koji; Kasugai, Atsushi; Hayashi, Kenichi; Ikeda, Yoshitaka; Kajiwara, Ken; Fujii, Tsuneyuki; Imai, Tsuyoshi; Kariya, Tsuyoshi; Mitsunaka, Yoshika

2003-01-01

Recent progress of electron cyclotron (EC) heating and current drive technologies in JAERI is reported. In 170 GHz gyrotron development, 0.9 MW/9.2 sec (efficiency: 43%), 0.5 MW/30 sec (46%), etc, have been demonstrated. As for 110 GHz gyrotron, 1 MW/5 sec and 1.2 MW/4.1 sec were obtained. Using four 110 GHz gyrotrons, a 3 MW power injection into JT- 60U plasma was carried out. In parallel, a launcher design and its development that includes neutron irradiation of the launcher components and a remote steering launcher are underway for ITER application. (authors)

X-ray sources in regions of star formation. I. The naked T Tauri stars

International Nuclear Information System (INIS)

Walter, F.M.

1986-01-01

Einstein X-ray observations of regions of active star formation in Taurus, Ophiuchus, and Corona Australis show a greatly enhanced surface density of stellar X-ray sources over that seen in other parts of the sky. Many of the X-ray sources are identified with low-mass, pre-main-sequence stars which are not classical T Tauri stars. The X-ray, photometric, and spectroscopic data for these stars are discussed. Seven early K stars in Oph and CrA are likely to be 1-solar-mass post-T Tauri stars with ages of 10-million yr. The late K stars in Taurus are not post-T Tauri, but naked T Tauri stars, which are coeval with the T Tauri stars, differing mainly in the lack of a circumstellar envelope. 72 references

SerpinE2, a poor biomarker of endometrial cancer, promotes the proliferation and mobility of EC cells.

Science.gov (United States)

Shen, Yuan; Wang, Xiaoyu; Xu, Jianping; Lu, Lin

2017-07-04

The SerpinE2 pathway is evolutionarily conserved and plays an important role in tumorigenesis. SerpinE2 (a small ubiquitin-related modifier), like ubiquitin, conjugates SerpinE2 proteins onto lysine residues of target proteins. SerpinE2 over-expression has been found in several tumors. Here, we detected the level of SerpinE2 in 72 samples of EC tissue using immunohistochemistry to assess the role of SerpinE2 in EC prognosis. Meanwhile, we knocked down SerpinE2 by siRNA in the HTB-111 and Ishikawa EC cell lines and analyzed the viability and mobility change using an MTT assay, an annexin V/PI apoptosis assay, a wound scratch test and a transwell assay. A Kaplan-Meier analysis indicated a negative correlation between the level of SerpinE2 and the EC prognosis. Silencing SerpinE2 induced cell apoptosis and reduced the migration ability. Our data suggest SerpinE2 works as an oncogene in EC.

Wave Star

DEFF Research Database (Denmark)

Kramer, Morten; Brorsen, Michael; Frigaard, Peter

Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

Descendants of the first stars: the distinct chemical signature of second generation stars

Science.gov (United States)

Hartwig, Tilman; Yoshida, Naoki; Magg, Mattis; Frebel, Anna; Glover, Simon C. O.; Gómez, Facundo A.; Griffen, Brendan; Ishigaki, Miho N.; Ji, Alexander P.; Klessen, Ralf S.; O'Shea, Brian W.; Tominaga, Nozomu

2018-05-01

Extremely metal-poor (EMP) stars in the Milky Way (MW) allow us to infer the properties of their progenitors by comparing their chemical composition to the metal yields of the first supernovae. This method is most powerful when applied to mono-enriched stars, i.e. stars that formed from gas that was enriched by only one previous supernova. We present a novel diagnostic to identify this subclass of EMP stars. We model the first generations of star formation semi-analytically, based on dark matter halo merger trees that yield MW-like halos at the present day. Radiative and chemical feedback are included self-consistently and we trace all elements up to zinc. Mono-enriched stars account for only ˜1% of second generation stars in our fiducial model and we provide an analytical formula for this probability. We also present a novel analytical diagnostic to identify mono-enriched stars, based on the metal yields of the first supernovae. This new diagnostic allows us to derive our main results independently from the specific assumptions made regarding Pop III star formation, and we apply it to a set of observed EMP stars to demonstrate its strengths and limitations. Our results may provide selection criteria for current and future surveys and therefore contribute to a deeper understanding of EMP stars and their progenitors.

PRODUCTION OF BACTERIOCIN EC2 AND ITS INTERFERENCE IN THE GROWTH OF SALMONELLA TYPHI IN A MILK MATRIX

Directory of Open Access Journals (Sweden)

Yuri de Jesus Lopes de Abreu

2013-08-01

Full Text Available Bacterial interference can occur through various mechanisms, including the production of peroxides, acids, ammonia, bacteriolytic enzymes or bacteriocins. The strain Escherichia coli EC2 produces the antimicrobial substance (AMS EC2, able to inhibit different strains of Gram-negative bacteria isolated from food, as E. coli and Salmonella sp. The activity of AMS EC2 was lost after treatment with proteolytic enzymes, indicating the presence of an active proteinaceous compound, suggesting that it is a bacteriocin. The substance, renamed bacteriocin EC2, has its better production when the producer strain is grown on Casoy medium, at 37ºC and pH 6.0, without NaCl addition, but it is also able to be produced in milk. When co-cultivated in UHT milk with the producer strain E. coli EC2, the growth of the indicator strain Salmonella Typhi is totally inhibited within the first 4 hours of incubation, suggesting a potential application of bacteriocin EC2 in the control of Salmonella sp. e.g. in foods.

Neutron star formation in theoretical supernovae. Low mass stars and white dwarfs

International Nuclear Information System (INIS)

Nomoto, K.

1986-01-01

The presupernova evolution of stars that form semi-degenerate or strongly degenerate O + Ne + Mg cores is discussed. For the 10 to 13 Msub solar stars, behavior of off-center neon flashes is crucial. The 8 to 10 m/sub solar stars do not ignite neon and eventually collapse due to electron captures. Properties of supernova explosions and neutron stars expected from these low mass progenitors are compared with the Crab nebula. The conditions for which neutron stars form from accretion-induced collapse of white dwarfs in clsoe binary systems is also examined

Clinical comparison of technetium-99m-EC, technetium-99-m-MAG3 and Iodine-131-OIH in renal disorders

International Nuclear Information System (INIS)

Kabasakal, L.; Turoglu, T.; Oensel, C.

1995-01-01

Technetium-99m-ethylenedicysteine has recently been developed for renal function studies. The pharmacokinetics of 99m Tc-EC were studied by constant infusion technique and compared with 99m Tc-MAG3 and 131 I-OIH in 11 patients with various renal disorders. After giving a 7.4 MBq 131 I-OIH and 90-110 MBq 99m Tc-EC or 99m Tc-MAG3 bolus, a constant infusion (MBq/ml) 99m Tc--agent and 0.07 MBq/m 131 I-OIH was started. Sixteen blood and five urine samples were obtained over three hr. The renal clearance of 99m Tc-EC was higher than than of 99m Tc-MAG3. The 99m Tc-EC/OIH and 99m Tc-MAG3/OIH ratios were 0.75 ± 0.05 and 0.55 ± 0.10 (p=0.00087), respectively. The distribution volume of 99m Tc-EC was also higher than that of 99m Tc-MAG3 (15722 ± 4644 and 9509 ± 2788 ml/1.73m 2 , respectively; p=0.072). The 99m Tc-EC/OIH and 99m Tc-MAG/OIH distribution volume ratios were 1.03 ± 0.14 and 0.55 ± 0.10, respectively (p = 0.0003). The 60-min excretion values of 99m Tc-EC and 99m Tc-MAG3 were compared to that of OIH. The 99m Tc-EC/OIH and 99m Tc-MAG3/OIH excretion ratios were 0.96 ± 0.06 and 1.07 ± 0.10, respectively (p=0.162). The protein binding of 99m -EC and OIH were found to be 34% ±4 and 66% ±5, respectively (p 99m Tc-EC was negligible (3% ±1.2) in comparison to OIH (27% ±3; p 99m Tc-EC. This agent has good potential for renal function evaluation. 32 refs., 5 tabs

Achievements and bottlenecks in humanitarian demining EU-funded research: final results from the EC DELVE project

Science.gov (United States)

Sahli, Hichem; Bruschini, Claudio; Van Kempen, Luc; Schleijpen, Ric; den Breejen, Eric

2008-04-01

The EC DELVE Support Action project has analyzed the bottlenecks in the transfer of Humanitarian Demining (HD) technology from technology development to the use in the field, and drawn some lessons learned, basing itself on the assessment of the European Humanitarian Demining Research and Technology Development (RTD) situation from early 1990 until 2006. The situation at the European level was analyzed with emphasis on activities sponsored by the European Commission (EC). This was also done for four European countries and Japan, with emphasis on national activities. The developments in HD during the last 10 years underline the fact that in a number of cases demining related developments have been terminated or at least put on hold. The study also showed that the funding provided by the EC under the Framework Program for RTD has led directly to the creation of an extensive portfolio of Humanitarian Demining technology development projects. The latter provided a range of research and supporting measures addressing the critical issues identified as a result of the regulatory policies developed in the field of Humanitarian Demining over the last ten years. However, the range of instruments available to the EC to finance the necessary research and development were limited, to pre-competitive research. The EC had no tools or programs to directly fund actual product development. As a first consequence, the EC funding program for development of technology for Humanitarian Demining unfortunately proved to be largely unsuitable for the small-scale development needed in a field where there is only a very limited market. As a second consequence, most of the research has been demonstrator-oriented. Moreover, the timeframe for RTD in Humanitarian Demining has not been sufficiently synchronized with the timeframe of the EC policies and regulations. The separation of the Mine Action and RTD funding streams in the EC did also negatively affect the take-up of new technologies. As a

General Relativity and Compact Stars

International Nuclear Information System (INIS)

Glendenning, Norman K.

2005-01-01

Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10 14 times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed

The biodistribution and radiation dosimetry of 99Tcmm-EC-DG in normal volunteers

International Nuclear Information System (INIS)

Tang Jun; Yang Yi; Liu Zengli; Shi Yizhen

2010-01-01

The objective of this study is to evaluate the biodistribution of technetium-99m labeled ethylenedicysteine-deoxyglucose ( 99 Tc m -EC-DG) and to calculate its internal radiation absorbed dose in normal volunteers. 740 MBq 99 Tc m -EC-DG was injected into the antecubital vein. 2 ml blood were sampled from the contralateral antecubital vein at different time after the injection, and its radioactivity was measured. The bi-exponential curve of time-radioactivity of blood and the dynamic parameters were obtained by using ORIGIN 5.0. Urine was collected in 24 hours after the injection and the percentage of Radioactivity excreted by urine to the total injected radioactivity was calculated. The anterior and posterior whole body imaging were acquired at different time after the injection of 740 MBq 99 Tc m -EC-DG. The region of interest of these referring organs and tissues was drawn, their radioactivity at different time was calculated. The bi-exponential curve of time-radioactivity of every organ was obtained by using ORIGIN 5.0, and then cumulated radioactivity and retaining time of 99 Tcm-EC-DG were calculated and input into the software MIRDOSE 3.0 to obtain the radiation absorbed dose of every organ and tissue. The heart rate, blood pressure and breathing frequency is normal after the injection. The male volunteer's T1/2α is 39 seconds, T1/2β is 59 minutes and that of female volunteer is 21 seconds and 61 minutes. 99 Tc m -EC-DG imaging is safe, and its characteristic of biodistribution in normal volunteer makes it easy to accumulate in tumor. Brain is not imaged, the uptake of muscle is low. The absorbed dose of every organ is far lower than that of the public annual average limitation. (authors)

Expression of a finger millet transcription factor, EcNAC1, in tobacco confers abiotic stress-tolerance.

Directory of Open Access Journals (Sweden)

Venkategowda Ramegowda

Full Text Available NAC (NAM, ATAF1-2, and CUC2 proteins constitute one of the largest families of plant-specific transcription factors and have been shown to be involved in diverse plant processes including plant growth, development, and stress-tolerance. In this study, a stress-responsive NAC gene, EcNAC1, was isolated from the subtracted stress cDNA library generated from a drought adapted crop, finger millet, and characterized for its role in stress-tolerance. The expression analysis showed that EcNAC1 was highly induced during water-deficit and salt stress. EcNAC1 shares high amino acid similarity with rice genes that have been phylogenetically classified into stress-related NAC genes. Our results demonstrated that tobacco transgenic plants expressing EcNAC1 exhibit tolerance to various abiotic stresses like simulated osmotic stress, by polyethylene glycol (PEG and mannitol, and salinity stress. The transgenic plants also showed enhanced tolerance to methyl-viologen (MV induced oxidative stress. Reduced levels of reactive oxygen species (ROS and ROS-induced damage were noticed in pot grown transgenic lines under water-deficit and natural high light conditions. Root growth under stress and recovery growth after stress alleviation was more in transgenic plants. Many stress-responsive genes were found to be up-regulated in transgenic lines expressing EcNAC1. Our results suggest that EcNAC1 overexpression confers tolerance against abiotic stress in susceptible species, tobacco.

Star formation

International Nuclear Information System (INIS)

Woodward, P.R.

1978-01-01

Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

Dark stars: a new study of the first stars in the Universe

International Nuclear Information System (INIS)

Freese, Katherine; Bodenheimer, Peter; Gondolo, Paolo; Spolyar, Douglas

2009-01-01

We have proposed that the first phase of stellar evolution in the history of the Universe may be dark stars (DSs), powered by dark matter (DM) heating rather than by nuclear fusion. Weakly interacting massive particles, which may be their own antipartners, collect inside the first stars and annihilate to produce a heat source that can power the stars. A new stellar phase results, a DS, powered by DM annihilation as long as there is DM fuel, with lifetimes from millions to billions of years. We find that the first stars are very bright (∼10 6 L o-dot ) and cool (T surf surf > 50 000 K); hence DS should be observationally distinct from standard Pop III stars. Once the DM fuel is exhausted, the DS becomes a heavy main sequence star; these stars eventually collapse to form massive black holes that may provide seeds for supermassive black holes observed at early times as well as explanations for recent ARCADE data and for intermediate black holes.

Introduction to neutron stars

Energy Technology Data Exchange (ETDEWEB)

Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

2015-02-24

Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

Polarization of Be stars

International Nuclear Information System (INIS)

Johns, M.W.

1975-01-01

Linear polarization of starlight may be produced by electron scattering in the extended atmospheres of early type stars. Techniques are investigated for the measurement and interpretation of this polarization. Polarimetric observations were made of twelve visual double star systems in which at least one member was a B type star as a means of separating the intrinsic stellar polarization from the polarization produced in the interstellar medium. Four of the double stars contained a Be star. Evidence for intrinsic polarization was found in five systems including two of the Be systems, one double star with a short period eclipsing binary, and two systems containing only normal early type stars for which emission lines have not been previously reported. The interpretation of these observations in terms of individual stellar polarizations and their wavelength dependence is discussed. The theoretical basis for the intrinsic polarization of early type stars is explored with a model for the disk-like extended atmospheres of Be stars. Details of a polarimeter for the measurement of the linear polarization of astronomical point sources are also presented with narrow band (Δ lambda = 100A) measurements of the polarization of γ Cas from lambda 4000 to lambda 5800

Modulation of biosynthesis and regulatory action of 24(S),25-epoxycholesterol (S-EC) in cultured cells by progesterone (PG)

International Nuclear Information System (INIS)

Panini, S.R.; Gupta, A.K.; Sexton, R.C.; Parish, E.J.; Rudney, H.

1987-01-01

Treatment of IEC-6 cells with PG caused a strong inhibition of cholesterol biosynthesis at the level of desmosterol reductase. In addition, two new products were observed in PG-treated cells. The first compound was designated as cholesta-5,7,24-trien-3β-ol based on its HPLC chromatographic properties. The second compound was identified as S-EC based on (1) a comparison of its chromatographic properties with those of authentic EC and (2) by its conversion to 25-hydroxycholesterol (HC) upon reduction with LiAlH 4 . In spite of cellular accumulation of S-EC in the presence of PG, the activity of HMG-CoA reductase (HMGR) which is known to be sensitive to oxysterols, was elevated rather than suppressed. On the other hand, when PG-treated cells were refed fresh medium without PG, HMGR activity was suppressed. Exogenous S-EC was a potent suppressor of HMGR in untreated IEC-6 cells. Suppression of HMGR by S-EC but not by HC could be prevented by progesterone. Exogenous [ 3 H]S-EC was not metabolized by IEC-6 cells. These results support the hypothesis that S-EC plays a normal regulatory role in sterol biosynthesis and indicate that enhanced S-EC synthesis observed in the presence of PG may be due to interference with this regulatory action

Rates of star formation

International Nuclear Information System (INIS)

Larson, R.B.

1977-01-01

It is illustrated that a theoretical understanding of the formation and evolution of galaxies depends on an understanding of star formation, and especially of the factors influencing the rate of star formation. Some of the theoretical problems of star formation in galaxies, some approaches that have been considered in models of galaxy evolution, and some possible observational tests that may help to clarify which processes or models are most relevant are reviewed. The material is presented under the following headings: power-law models for star formation, star formation processes (conditions required, ways of achieving these conditions), observational indications and tests, and measures of star formation rates in galaxies. 49 references

Inter-comparison of NIOSH and IMPROVE protocols for OC and EC determination: implications for inter-protocol data conversion

Science.gov (United States)

Wu, Cheng; Huang, X. H. Hilda; Ng, Wai Man; Griffith, Stephen M.; Zhen Yu, Jian

2016-09-01

Organic carbon (OC) and elemental carbon (EC) are operationally defined by analytical methods. As a result, OC and EC measurements are protocol dependent, leading to uncertainties in their quantification. In this study, more than 1300 Hong Kong samples were analyzed using both National Institute for Occupational Safety and Health (NIOSH) thermal optical transmittance (TOT) and Interagency Monitoring of Protected Visual Environment (IMPROVE) thermal optical reflectance (TOR) protocols to explore the cause of EC disagreement between the two protocols. EC discrepancy mainly (83 %) arises from a difference in peak inert mode temperature, which determines the allocation of OC4NSH, while the rest (17 %) is attributed to a difference in the optical method (transmittance vs. reflectance) applied for the charring correction. Evidence shows that the magnitude of the EC discrepancy is positively correlated with the intensity of the biomass burning signal, whereby biomass burning increases the fraction of OC4NSH and widens the disagreement in the inter-protocol EC determination. It is also found that the EC discrepancy is positively correlated with the abundance of metal oxide in the samples. Two approaches (M1 and M2) that translate NIOSH TOT OC and EC data into IMPROVE TOR OC and EC data are proposed. M1 uses direct relationship between ECNSH_TOT and ECIMP_TOR for reconstruction: M1 : ECIMP_TOR = a × ECNSH_TOT + b; while M2 deconstructs ECIMP_TOR into several terms based on analysis principles and applies regression only on the unknown terms: M2 : ECIMP_TOR = AECNSH + OC4NSH - (a × PCNSH_TOR + b), where AECNSH, apparent EC by the NIOSH protocol, is the carbon that evolves in the He-O2 analysis stage, OC4NSH is the carbon that evolves at the fourth temperature step of the pure helium analysis stage of NIOSH, and PCNSH_TOR is the pyrolyzed carbon as determined by the NIOSH protocol. The implementation of M1 to all urban site data (without considering seasonal specificity

EC tells Bonn let in UK coal

Energy Technology Data Exchange (ETDEWEB)

1992-06-23

The European Commission has told the German federal government to open the door for coal imports from other EC member countries. As an initial step, the Commission is suggesting that some of the power station coal which was to be sourced from German stockpiles under the November 1991 agreement between Rurhkohle AG, the state mining company and the generators, be supplied by other member states such as the UK. The implications of this move for the German coal industry are discussed. 2 tabs.

The Drifting Star

Science.gov (United States)

2008-04-01

By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way. ESO PR Photo 09a/08 ESO PR Photo 09a/08 Iota Horologii The yellow-orange star Iota Horologii, located 56 light-years away towards the southern Horologium ("The Clock") constellation, belongs to the so-called "Hyades stream", a large number of stars that move in the same direction. Previously, astronomers using an ESO telescope had shown that the star harbours a planet, more than 2 times as large as Jupiter and orbiting in 320 days (ESO 12/99). But until now, all studies were unable to pinpoint the exact characteristics of the star, and hence to understand its origin. A team of astronomers, led by Sylvie Vauclair from the University of Toulouse, France, therefore decided to use the technique of 'asteroseismology' to unlock the star's secrets. "In the same way as geologists monitor how seismic waves generated by earthquakes propagate through the Earth and learn about the inner structure of our planet, it is possible to study sound waves running through a star, which forms a sort of large, spherical bell," says Vauclair. The 'ringing' from this giant musical instrument provides astronomers with plenty of information about the physical conditions in the star's interior. And to 'listen to the music', the astronomers used one of the best instruments available. The observations were conducted in November 2006 during 8 consecutive nights with the state-of-the-art HARPS spectrograph mounted on the ESO 3.6-m telescope at La Silla. Up to 25 'notes' could be identified in the unique dataset, most of them corresponding to waves having a period of about 6.5 minutes. These observations allowed the astronomers to obtain a very precise portrait of Iota Horologii: its

INFRARED TWO-COLOR DIAGRAMS FOR AGB STARS, POST-AGB STARS, AND PLANETARY NEBULAE

Energy Technology Data Exchange (ETDEWEB)

Suh, Kyung-Won, E-mail: kwsuh@chungbuk.ac.kr [Department of Astronomy and Space Science, Chungbuk National University, Cheongju-City, 362-763 (Korea, Republic of)

2015-08-01

We present various infrared two-color diagrams (2CDs) for asymptotic giant branch (AGB) stars, post-AGB stars, and Planetary Nebulae (PNe) and investigate possible evolutionary tracks. We use catalogs from the available literature for the sample of 4903 AGB stars (3373 O-rich; 1168 C-rich; 362 S-type), 660 post-AGB stars (326 post-AGB; 334 pre-PN), and 1510 PNe in our Galaxy. For each object in the catalog, we cross-identify the IRAS, AKARI, Midcourse Space Experiment, and 2MASS counterparts. The IR 2CDs can provide useful information about the structure and evolution of the dust envelopes as well as the central stars. To find possible evolutionary tracks from AGB stars to PNe on the 2CDs, we investigate spectral evolution of post-AGB stars by making simple but reasonable assumptions on the evolution of the central star and dust shell. We perform radiative transfer model calculations for the detached dust shells around evolving central stars in the post-AGB phase. We find that the theoretical dust shell model tracks using dust opacity functions of amorphous silicate and amorphous carbon roughly coincide with the densely populated observed points of AGB stars, post-AGB stars, and PNe on various IR 2CDs. Even though some discrepancies are inevitable, the end points of the theoretical post-AGB model tracks generally converge in the region of the observed points of PNe on most 2CDs.

Interacting binary stars

CERN Document Server

Sahade, Jorge; Ter Haar, D

1978-01-01

Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

Wolf-Rayet stars and O-star runaways with HIPPARCOS - I. Kinematics

NARCIS (Netherlands)

Moffat, AFJ; Marchenko, SV; Seggewiss, W; van der Hucht, KA; Schrijver, H; Stenholm, B; Lundstrom, [No Value; Gunawan, DYAS; Sutantyo, W; van den Heuvel, EPJ; De Cuyper, JP; Gomez, AE

Reliable systemic radial velocities are almost impossible to secure for Wolf-Rayet stars, difficult for O stars. Therefore, to study the motions - both systematic in the Galaxy and peculiar - of these two related types of hot, luminous star, we have examined the Hipparcos proper motions of some 70

Evolution of variable stars

International Nuclear Information System (INIS)

Becker, S.A.

1986-08-01

Throughout the domain of the H R diagram lie groupings of stars whose luminosity varies with time. These variable stars can be classified based on their observed properties into distinct types such as β Cephei stars, δ Cephei stars, and Miras, as well as many other categories. The underlying mechanism for the variability is generally felt to be due to four different causes: geometric effects, rotation, eruptive processes, and pulsation. In this review the focus will be on pulsation variables and how the theory of stellar evolution can be used to explain how the various regions of variability on the H R diagram are populated. To this end a generalized discussion of the evolutionary behavior of a massive star, an intermediate mass star, and a low mass star will be presented. 19 refs., 1 fig., 1 tab

A new method for determining which stars are near a star sensor field-of-view

Science.gov (United States)

Yates, Russell E., Jr.; Vedder, John D.

1991-01-01

A new method is described for determining which stars in a navigation star catalog are near a star sensor field of view (FOV). This method assumes that an estimate of spacecraft inertial attitude is known. Vector component ranges for the star sensor FOV are computed, so that stars whose vector components lie within these ranges are near the star sensor FOV. This method requires no presorting of the navigation star catalog, and is more efficient than tradition methods.

Star identification methods, techniques and algorithms

CERN Document Server

Zhang, Guangjun

2017-01-01

This book summarizes the research advances in star identification that the author’s team has made over the past 10 years, systematically introducing the principles of star identification, general methods, key techniques and practicable algorithms. It also offers examples of hardware implementation and performance evaluation for the star identification algorithms. Star identification is the key step for celestial navigation and greatly improves the performance of star sensors, and as such the book include the fundamentals of star sensors and celestial navigation, the processing of the star catalog and star images, star identification using modified triangle algorithms, star identification using star patterns and using neural networks, rapid star tracking using star matching between adjacent frames, as well as implementation hardware and using performance tests for star identification. It is not only valuable as a reference book for star sensor designers and researchers working in pattern recognition and othe...

On the evolution of stars

International Nuclear Information System (INIS)

Kippenhahn, R.

1989-01-01

A popular survey is given of the present knowledge on evolution and ageing of stars. Main sequence stars, white dwarf stars, and red giant stars are classified in the Hertzsprung-Russell (HR)-diagram by measurable quantities: surface temperature and luminosity. From the HR-diagram it can be concluded to star mass and age. Star-forming processes in interstellar clouds as well as stellar burning processes are illustrated. The changes occurring in a star due to the depletion of the nuclear energy reserve are described. In this frame the phenomena of planetary nebulae, supernovae, pulsars, neutron stars as well as of black holes are explained

MAGNETIC FIELDS OF STARS

OpenAIRE

Bychkov, V. D.; Bychkova, L. V.; Madej, J.

2008-01-01

Now it is known about 1212 stars of the main sequence and giants (from them 610 stars - it is chemically peculiarity (CP) stars) for which direct measurements of magnetic fields were spent (Bychkov et al.,2008). Let's consider, what representations were generated about magnetic fields (MT) of stars on the basis of available observations data.

GPM GROUND VALIDATION ENVIRONMENT CANADA (EC) VAISALA CEILOMETER GCPEX V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation Environment Canada (EC) VAISALA Ceilometer GCPEx dataset was collected during the GPM Cold-season Precipitation Experiment (GCPEx) in...

Technique charts for EC film: direct optical measurements to account for the effects of X-ray scatter

International Nuclear Information System (INIS)

Munro, Peter; Jordan, Kevin; Lewis, Craig; Heerema, Tim

2001-01-01

Purpose: To develop a method of measuring technique charts for enhanced contrast (EC) film, to demonstrate how X-ray scatter changes the response of EC film, and to generate technique charts for general use. Methods and Materials: We have developed a 'digital cassette' - consisting of a metal plate/phosphor screen, a light guide, a photodiode sensor, and an electrometer - that can be used to measure the light generated in the phosphor screen of the film cassette. In turn, these measurements can be used to generate technique charts for EC film. The digital cassette has been used to measure technique charts for 4-MV and 6-MV X-ray beams for a variety of different phantom thicknesses, field sizes, and phantom-to-cassette air gaps. Results and Discussion: We have observed that the signals generated in an ionization chamber located 9.4 cm behind a 30-cm-thick water-equivalent phantom increase by a factor of 1.9 when the field size is increased from 4x4 cm 2 to 40x40 cm 2 when irradiated by a 6-MV X-ray beam. However, the change in EC film response is a factor of 3.5 under the same conditions. Irradiations to optimally expose the EC film predicted by the digital cassette differ by up to 82% compared to those predicted by ion chamber measurements. Nevertheless, the technique charts measured using the digital cassette predict the response of the EC film to ±0.2 optical density. The overresponse of the EC film is most likely due to low-energy scattered photons, which interact with the high atomic number (Z=64) phosphor screen of the enhanced contrast localization cassette. Therefore, simple solutions, such as placing a high atomic number material above the enhanced contrast localization cassette, can reduce this contribution by scattered photons to the signal generated in the cassettes. Conclusions: We have developed a digital cassette that can make more accurate measurements of the technique charts for EC films. Our measurements show that under some conditions, X

Which of Kepler's Stars Flare?

Science.gov (United States)

Kohler, Susanna

2017-12-01

The habitability of distant exoplanets is dependent upon many factors one of which is the activity of their host stars. To learn about which stars are most likely to flare, a recent study examines tens of thousands of stellar flares observed by Kepler.Need for a Broader SampleArtists rendering of a flaring dwarf star. [NASAs Goddard Space Flight Center/S. Wiessinger]Most of our understanding of what causes a star to flare is based on observations of the only star near enough to examine in detail the Sun. But in learning from a sample size of one, a challenge arises: we must determine which conclusions are unique to the Sun (or Sun-like stars), and which apply to other stellar types as well.Based on observations and modeling, astronomers think that stellar flares result from the reconnection of magnetic field lines in a stars outer atmosphere, the corona. The magnetic activity is thought to be driven by a dynamo caused by motions in the stars convective zone.HR diagram of the Kepler stars, with flaring main-sequence (yellow), giant (red) and A-star (green) stars in the authors sample indicated. [Van Doorsselaere et al. 2017]To test whether these ideas are true generally, we need to understand what types of stars exhibit flares, and what stellar properties correlate with flaring activity. A team of scientists led by Tom Van Doorsselaere (KU Leuven, Belgium) has now used an enormous sample of flares observed by Kepler to explore these statistics.Intriguing TrendsVan Doorsselaere and collaborators used a new automated flare detection and characterization algorithm to search through the raw light curves from Quarter 15 of the Kepler mission, building a sample of 16,850 flares on 6,662 stars. They then used these to study the dependence of the flare occurrence rate, duration, energy, and amplitude on the stellar spectral type and rotation period.This large statistical study led the authors to several interesting conclusions, including:Flare star incidence rate as a a

Symbiotic stars

Science.gov (United States)

Kafatos, M.; Michalitsianos, A. G.

1984-01-01

The physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.

Massive stars in galaxies

International Nuclear Information System (INIS)

Humphreys, R.M.

1987-01-01

The relationship between the morphologic type of a galaxy and the evolution of its massive stars is explored, reviewing observational results for nearby galaxies. The data are presented in diagrams, and it is found that the massive-star populations of most Sc spiral galaxies and irregular galaxies are similar, while those of Sb spirals such as M 31 and M 81 may be affected by morphology (via differences in the initial mass function or star-formation rate). Consideration is also given to the stability-related upper luminosity limit in the H-R diagram of hypergiant stars (attributed to radiation pressure in hot stars and turbulence in cool stars) and the goals of future observation campaigns. 88 references

GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation

Energy Technology Data Exchange (ETDEWEB)

Wu, Benjamin [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Tan, Jonathan C. [Department of Physics, University of Florida, Gainesville, FL 32611 (United States); Christie, Duncan [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Nakamura, Fumitaka [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Van Loo, Sven [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Collins, David, E-mail: ben.wu@nao.ac.jp [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

2017-06-01

We study giant molecular cloud (GMC) collisions and their ability to trigger star cluster formation. We further develop our three-dimensional magnetized, turbulent, colliding GMC simulations by implementing star formation subgrid models. Two such models are explored: (1) “Density-Regulated,” i.e., fixed efficiency per free-fall time above a set density threshold and (2) “Magnetically Regulated,” i.e., fixed efficiency per free-fall time in regions that are magnetically supercritical. Variations of parameters associated with these models are also explored. In the non-colliding simulations, the overall level of star formation is sensitive to model parameter choices that relate to effective density thresholds. In the GMC collision simulations, the final star formation rates and efficiencies are relatively independent of these parameters. Between the non-colliding and colliding cases, we compare the morphologies of the resulting star clusters, properties of star-forming gas, time evolution of the star formation rate (SFR), spatial clustering of the stars, and resulting kinematics of the stars in comparison to the natal gas. We find that typical collisions, by creating larger amounts of dense gas, trigger earlier and enhanced star formation, resulting in 10 times higher SFRs and efficiencies. The star clusters formed from GMC collisions show greater spatial substructure and more disturbed kinematics.

An Autonomous Star Identification Algorithm Based on One-Dimensional Vector Pattern for Star Sensors.

Science.gov (United States)

Luo, Liyan; Xu, Luping; Zhang, Hua

2015-07-07

In order to enhance the robustness and accelerate the recognition speed of star identification, an autonomous star identification algorithm for star sensors is proposed based on the one-dimensional vector pattern (one_DVP). In the proposed algorithm, the space geometry information of the observed stars is used to form the one-dimensional vector pattern of the observed star. The one-dimensional vector pattern of the same observed star remains unchanged when the stellar image rotates, so the problem of star identification is simplified as the comparison of the two feature vectors. The one-dimensional vector pattern is adopted to build the feature vector of the star pattern, which makes it possible to identify the observed stars robustly. The characteristics of the feature vector and the proposed search strategy for the matching pattern make it possible to achieve the recognition result as quickly as possible. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition accuracy and robustness by the proposed algorithm are better than those by the pyramid algorithm, the modified grid algorithm, and the LPT algorithm. The theoretical analysis and experimental results show that the proposed algorithm outperforms the other three star identification algorithms.

Subluminous Wolf-Rayet stars: Observations

International Nuclear Information System (INIS)

Heap, S.R.

1982-01-01

The author has used the fact that some central stars are WR stars and others are say, O stars, as a focal point for his presentation. In attempting to answer this question he has considered how the properties of WR-type central stars differ from those of O-type stars. The study begins with the classification and calibration of WR spectra, then goes on to the physical properties of WR-type central stars, and at the end returns to the question of what distinguishes a Wolf-Rayet star. The observational data for central stars are neither complete nor precise. Nevertheless, they suggest that what distinguishes a WR central star is not so much its present physical properties (e.g. temperature, gravity), but rather, its fundamental properties (initial and evolutionary history). (Auth.)

Uncertainty in CH4 and N2O emission estimates from a managed fen meadow using EC measurements

International Nuclear Information System (INIS)

Kroon, P.S.; Hensen, A.; Van 't Veen, W.H.; Vermeulen, A.T.; Jonker, H.

2009-02-01

The overall uncertainty in annual flux estimates derived from chamber measurements may be as high as 50% due to the temporal and spatial variability in the fluxes. As even a large number of chamber plots still cover typically less than 1% of the total field area, the field-scale integrated emission necessarily remains a matter of speculation. High frequency micrometeorological methods are a good option for obtaining integrated estimates on a hectare scale with a continuous coverage in time. Instrumentation is now becoming available that meets the requirements for CH4 and N2O eddy covariance (EC) measurements. A system consisting of a quantum cascade laser (QCL) spectrometer and a sonic anemometer has recently been proven to be suitable for performing EC measurements. This study analyses the EC flux measurements of CH4 and N2O and its corrections, like calibration, Webb-correction, and corrections for high and low frequency losses, and assesses the magnitude of the uncertainties associated with the precision of the measurement instruments, measurement set-up and the methodology. The uncertainty of one single EC flux measurement, a daily, monthly and 3-monthly average EC flux is estimated. In addition, the cumulative emission of C-CH4 and N-N2O and their uncertainties are determined over several fertilizing events at a dairy farm site in the Netherlands. These fertilizing events are selected from the continuously EC flux measurements from August 2006 to September 2008. The EC flux uncertainties are compared by the overall uncertainty in annual flux estimates derived from chamber measurements. It will be shown that EC flux measurements can decrease the overall uncertainty in annual flux estimates

Uncertainty in CH4 and N2O emission estimates from a managed fen meadow using EC measurements

Energy Technology Data Exchange (ETDEWEB)

Kroon, P.S.; Hensen, A.; Van ' t Veen, W.H.; Vermeulen, A.T. [ECN Biomass, Coal and Environment, Petten (Netherlands); Jonker, H. [Delft University of Technology, Delft (Netherlands)

2009-02-15

The overall uncertainty in annual flux estimates derived from chamber measurements may be as high as 50% due to the temporal and spatial variability in the fluxes. As even a large number of chamber plots still cover typically less than 1% of the total field area, the field-scale integrated emission necessarily remains a matter of speculation. High frequency micrometeorological methods are a good option for obtaining integrated estimates on a hectare scale with a continuous coverage in time. Instrumentation is now becoming available that meets the requirements for CH4 and N2O eddy covariance (EC) measurements. A system consisting of a quantum cascade laser (QCL) spectrometer and a sonic anemometer has recently been proven to be suitable for performing EC measurements. This study analyses the EC flux measurements of CH4 and N2O and its corrections, like calibration, Webb-correction, and corrections for high and low frequency losses, and assesses the magnitude of the uncertainties associated with the precision of the measurement instruments, measurement set-up and the methodology. The uncertainty of one single EC flux measurement, a daily, monthly and 3-monthly average EC flux is estimated. In addition, the cumulative emission of C-CH4 and N-N2O and their uncertainties are determined over several fertilizing events at a dairy farm site in the Netherlands. These fertilizing events are selected from the continuously EC flux measurements from August 2006 to September 2008. The EC flux uncertainties are compared by the overall uncertainty in annual flux estimates derived from chamber measurements. It will be shown that EC flux measurements can decrease the overall uncertainty in annual flux estimates.

America's Star Libraries

Science.gov (United States)

Lyons, Ray; Lance, Keith Curry

2009-01-01

"Library Journal"'s new national rating of public libraries, the "LJ" Index of Public Library Service, identifies 256 "star" libraries. It rates 7,115 public libraries. The top libraries in each group get five, four, or three Michelin guide-like stars. All included libraries, stars or not, can use their scores to learn from their peers and improve…

Observing Double Stars

Science.gov (United States)

Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

2012-05-01

Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

Neutron star natal kicks and the long-term survival of star clusters

Science.gov (United States)

Contenta, Filippo; Varri, Anna Lisa; Heggie, Douglas C.

2015-04-01

We investigate the dynamical evolution of a star cluster in an external tidal field by using N-body simulations, with focus on the effects of the presence or absence of neutron star natal velocity kicks. We show that, even if neutron stars typically represent less than 2 per cent of the total bound mass of a star cluster, their primordial kinematic properties may affect the lifetime of the system by up to almost a factor of 4. We interpret this result in the light of two known modes of star cluster dissolution, dominated by either early stellar evolution mass-loss or two-body relaxation. The competition between these effects shapes the mass-loss profile of star clusters, which may either dissolve abruptly (`jumping'), in the pre-core-collapse phase, or gradually (`skiing'), after having reached core collapse.

Hyperfast pulsars as the remnants of massive stars ejected from young star clusters

Science.gov (United States)

Gvaramadze, Vasilii V.; Gualandris, Alessia; Portegies Zwart, Simon

2008-04-01

Recent proper motion and parallax measurements for the pulsar PSR B1508+55 indicate a transverse velocity of ~1100kms-1, which exceeds earlier measurements for any neutron star. The spin-down characteristics of PSR B1508+55 are typical for a non-recycled pulsar, which implies that the velocity of the pulsar cannot have originated from the second supernova disruption of a massive binary system. The high velocity of PSR B1508+55 can be accounted for by assuming that it received a kick at birth or that the neutron star was accelerated after its formation in the supernova explosion. We propose an explanation for the origin of hyperfast neutron stars based on the hypothesis that they could be the remnants of a symmetric supernova explosion of a high-velocity massive star which attained its peculiar velocity (similar to that of the pulsar) in the course of a strong dynamical three- or four-body encounter in the core of dense young star cluster. To check this hypothesis, we investigated three dynamical processes involving close encounters between: (i) two hard massive binaries, (ii) a hard binary and an intermediate-mass black hole (IMBH) and (iii) a single stars and a hard binary IMBH. We find that main-sequence O-type stars cannot be ejected from young massive star clusters with peculiar velocities high enough to explain the origin of hyperfast neutron stars, but lower mass main-sequence stars or the stripped helium cores of massive stars could be accelerated to hypervelocities. Our explanation for the origin of hyperfast pulsars requires a very dense stellar environment of the order of 106- 107starspc-3. Although such high densities may exist during the core collapse of young massive star clusters, we caution that they have never been observed.

Heavy Metal Stars

Science.gov (United States)

2001-08-01

La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing

Ultracompact X-ray binary stars

NARCIS (Netherlands)

Haaften, L.M. van

2013-01-01

Ultracompact X-ray binary stars usually consist of a neutron star and a white dwarf, two stars bound together by their strong gravity and orbiting each other very rapidly, completing one orbit in less than one hour. Neutron stars are extremely compact remnants of the collapsed cores of massive stars

The role of the IGF-1 Ec in myoskeletal system and osteosarcoma pathophysiology.

Science.gov (United States)

Armakolas, Nikolaos; Armakolas, Athanasios; Antonopoulos, Athanasios; Dimakakos, Andreas; Stathaki, Martha; Koutsilieris, Michael

2016-12-01

Growth hormone (GH) regulated mainly liver-produced insulin-like growth factor 1 (IGF-1) is a key molecule in embryonic & post embryonic development that is also involved in cancer biology. Herein we review new insights of the role of igf-1 gene products and of the IGF-1Ec isoform in muscle and bone development/repair and its role in osteosarcoma pathophysiology, underlying the possible role of the Ec peptide as a future therapeutic target. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Star Masses and Star-Planet Distances for Earth-like Habitability.

Science.gov (United States)

Waltham, David

2017-01-01

This paper presents statistical estimates for the location and duration of habitable zones (HZs) around stars of different mass. The approach is based upon the assumption that Earth's location, and the Sun's mass, should not be highly atypical of inhabited planets. The results support climate-model-based estimates for the location of the Sun's HZ except models giving a present-day outer-edge beyond 1.64 AU. The statistical approach also demonstrates that there is a habitability issue for stars smaller than 0.65 solar masses since, otherwise, Earth would be an extremely atypical inhabited world. It is difficult to remove this anomaly using the assumption that poor habitability of planets orbiting low-mass stars results from unfavorable radiation regimes either before, or after, their stars enter the main sequence. However, the anomaly is well explained if poor habitability results from tidal locking of planets in the HZs of small stars. The expected host-star mass for planets with intelligent life then has a 95% confidence range of 0.78 M ⊙ planets with at least simple life is 0.57 M ⊙  < M < 1.64 M ⊙ . Key Words: Habitability-Habitable zone-Anthropic-Red dwarfs-Initial mass function. Astrobiology 17, 61-77.

socio-ec(h)o: Ambient Intelligence and Gameplay

OpenAIRE

Wakkary, Ron

2005-01-01

The socio-ec(h)o project aims to research a generalized ambient intelligent software platform and design models for responsive environments based on the concept of ambient intelligent "ecologies" and group gameplay. The benefits of the research include a software-architecture, ambient intelligence inference engine, and interaction design models for gameplay and responsive environments. The paper will discuss the results of our prototypes for games in responsive environments. These prototypes ...

X-ray sources in stars formation areas: T Tauri stars and proto-stars in the rho Ophiuchi dark cloud

International Nuclear Information System (INIS)

Grosso, Nicolas

1999-01-01

This thesis studies from large to small scales, X-ray sources in the rho Ophiuchi dark cloud. After some background on the formation of the low-mass young stars (Chapter 1), Chapter 2 takes an interest in the T Tauri star population. Chapter 3 tackles the search of the magnetic activity at the younger stage of protostar, presenting a powerful X-ray emission from an IR protostar, called YLW15, during a flare, and a quasi-periodic flare of the same source; as well as a new detection of another IR protostar in the ROSAT archives. It ends with a review of protostar detections. Some IR protostar flares show a very long increasing phase. Chapter 4 links this behaviour with a modulation by the central star rotation. The standard model of jet emission assumes that the central star rotates at the same speed that the inner edge of its accretion disk. This chapter shows that the observation of the YLW15 quasi-periodic flare suggests rather that the forming star rotates faster than its accretion disk, at the break up limit. The synchronism with the accretion disk, observed on T Tauri stars, must be reach progressively by magnetic breaking during the IR protostar stage, and more or less rapidly depending on the forming star mass. Recent studies have shown that T Tauri star X-ray emission could ionize the circumstellar disk, and play a role in the instability development, as well as stimulate the accretion. The protostar X-ray emission might be higher than the T Tauri star one, Chapter 5 presents a millimetric interferometric observation dedicated to measure this effect on YLW15. Finally, Chapter 6 reassembles conclusions and perspectives of this work. (author) [fr

THE GALACTIC O-STAR SPECTROSCOPIC SURVEY (GOSSS). II. BRIGHT SOUTHERN STARS

International Nuclear Information System (INIS)

Sota, A.; Apellániz, J. Maíz; Alfaro, E. J.; Morrell, N. I.; Barbá, R. H.; Arias, J. I.; Walborn, N. R.; Gamen, R. C.

2014-01-01

We present the second installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R ∼ 2500 digital observations from both hemispheres selected from the Galactic O-Star Catalog (GOSC). In this paper we include bright stars and other objects drawn mostly from the first version of GOSC, all of them south of δ = –20°, for a total number of 258 O stars. We also revise the northern sample of Paper I to provide the full list of spectroscopically classified Galactic O stars complete to B = 8, bringing the total number of published GOSSS stars to 448. Extensive sequences of exceptional objects are given, including the early Of/WN, O Iafpe, Ofc, ON/OC, Onfp, Of?p, and Oe types, as well as double/triple-lined spectroscopic binaries. The new spectral subtype O9.2 is also discussed. The magnitude and spatial distributions of the observed sample are analyzed. We also present new results from OWN, a multi-epoch high-resolution spectroscopic survey coordinated with GOSSS that is assembling the largest sample of Galactic spectroscopic massive binaries ever attained. The OWN data combined with additional information on spectroscopic and visual binaries from the literature indicate that only a very small fraction (if any) of the stars with masses above 15-20 M ☉ are born as single systems. In the future we will publish the rest of the GOSSS survey, which is expected to include over 1000 Galactic O stars

Lithium in the barium stars

International Nuclear Information System (INIS)

Pinsonneault, M.H.; Sneden, C.

1984-01-01

New high-resolution spectra of the lithium resonance doublet have provided lithium abundances or upper limits for 26 classical and mild barium stars. The lithium lines always are present in the classical barium stars. Lithium abundances in these stars obey a trend with stellar masses consistent with that previously derived for ordinary K giants. This supports the notion that classical barium stars are post-core-He-flash or core-He-burning stars. Lithium contents in the mild barium stars, however, often are much smaller than those of the classical barium stars sometimes only upper limits may be determined. The cause for this difference is not easily understood, but may be related to more extensive mass loss by the mild barium stars. 45 references

[Characteristics and sources apportionment of OC and EC in PM1.1 from Nanjing].

Science.gov (United States)

Jiang, Wen-juan; Guo, Zhao-bing; Liu, Feng-ling; Rui, Mao-ling; Shi, Lei; Zeng, Gang; Guo, Zi-yan

2015-03-01

The concentrations of OC and EC in PM1.1 collected from Nanshi (NS) and Nanhua (NH) in 2011 were analyzed using DRI Model 2001A Thermal Optical Carbon Analyzer. In addition, source apportionment was simultaneously evaluated. The results showed that the annual average concentrations of OC and EC in PM1.1 were 10. 10 μg x m(-3) and 2.52 μg x m(-3) in NS area, and 11.22 μg x m(-3) and 3.12 μg x m(-3) in NH area, respectively. This result indicated that OC and EC pollution in NH was more serious than that in NS area. Meanwhile, the concentrations of OC and EC in winter and spring were obviously higher compared to those in summer in these two sampling sites, which was mainly ascribed to the increased coal combustion and the unfavorable emission condition of air pollutants in summer and spring. We noted that the SOC/TOC value was the highest in summer and the lowest in winter. In addition, the SOC concentration was observed to show a positive correlation with ozone concentrations, which indicated that the photochemical reaction was a main way of SOC formation in autumn.

Improved autonomous star identification algorithm

International Nuclear Information System (INIS)

Luo Li-Yan; Xu Lu-Ping; Zhang Hua; Sun Jing-Rong

2015-01-01

The log–polar transform (LPT) is introduced into the star identification because of its rotation invariance. An improved autonomous star identification algorithm is proposed in this paper to avoid the circular shift of the feature vector and to reduce the time consumed in the star identification algorithm using LPT. In the proposed algorithm, the star pattern of the same navigation star remains unchanged when the stellar image is rotated, which makes it able to reduce the star identification time. The logarithmic values of the plane distances between the navigation and its neighbor stars are adopted to structure the feature vector of the navigation star, which enhances the robustness of star identification. In addition, some efforts are made to make it able to find the identification result with fewer comparisons, instead of searching the whole feature database. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition rate and robustness by the proposed algorithm are better than those by the LPT algorithm and the modified grid algorithm. (paper)

Autonomous Star Tracker Algorithms

DEFF Research Database (Denmark)

Betto, Maurizio; Jørgensen, John Leif; Kilsgaard, Søren

1998-01-01

Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances.......Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances....

Acute and repeated ECS treatment increases CRF, POMC and PENK gene expression in selected regions of the rat hypothalamus.

Science.gov (United States)

Garcia-Garcia, L; Llewellyn-Jones, V; Fernandez Fernandez, I; Fuentes, J A; Manzanares, J

1998-01-05

The purpose of this study was to investigate the effects of acute and repeated electroconvulsive shock (ECS) on corticotropin releasing factor (CRF), proopiomelanocortin (POMC) and proenkephalin (PENK) gene expression in selected regions of the brain and pituitary of the rat. Acute ECS increased CRF gene expression in the paraventricular nucleus (PVN) by 20%, an effect that was further enhanced to 38% when rats received repeated ECS treatment. Acute and repeated ECS increased POMC gene expression in the arcuate nucleus (ARC) by 49-59% but failed to alter these mRNA levels in the anterior lobe (AL) of the pituitary gland. PENK gene expression was increased by 35% in the nucleus accumbens (NA) and by 180% the ventromedial nucleus (VMN) after acute or repeated ECS treatment but no significant changes were found in the PVN or striatum (ST). Taken together, these results indicate a differential CRF and opioid gene expression regulation after acute or repeated ECS treatment that may be relevant to their therapeutic or side effects in depression.

Nuclear physics of stars

CERN Document Server

Iliadis, Christian

2015-01-01

Most elements are synthesized, or ""cooked"", by thermonuclear reactions in stars. The newly formed elements are released into the interstellar medium during a star's lifetime, and are subsequently incorporated into a new generation of stars, into the planets that form around the stars, and into the life forms that originate on the planets. Moreover, the energy we depend on for life originates from nuclear reactions that occur at the center of the Sun. Synthesis of the elements and nuclear energy production in stars are the topics of nuclear astrophysics, which is the subject of this book

How the First Stars Regulated Star Formation. II. Enrichment by Nearby Supernovae

Energy Technology Data Exchange (ETDEWEB)

Chen, Ke-Jung [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan); Whalen, Daniel J. [Institute of Cosmology and Gravitation, Portsmouth University, Portsmouth (United Kingdom); Wollenberg, Katharina M. J.; Glover, Simon C. O.; Klessen, Ralf S., E-mail: ken.chen@nao.ac.jp [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg (Germany)

2017-08-01

Metals from Population III (Pop III) supernovae led to the formation of less massive Pop II stars in the early universe, altering the course of evolution of primeval galaxies and cosmological reionization. There are a variety of scenarios in which heavy elements from the first supernovae were taken up into second-generation stars, but cosmological simulations only model them on the largest scales. We present small-scale, high-resolution simulations of the chemical enrichment of a primordial halo by a nearby supernova after partial evaporation by the progenitor star. We find that ejecta from the explosion crash into and mix violently with ablative flows driven off the halo by the star, creating dense, enriched clumps capable of collapsing into Pop II stars. Metals may mix less efficiently with the partially exposed core of the halo, so it might form either Pop III or Pop II stars. Both Pop II and III stars may thus form after the collision if the ejecta do not strip all the gas from the halo. The partial evaporation of the halo prior to the explosion is crucial to its later enrichment by the supernova.

Cancer cells cause vascular endothelial cell (vEC) retraction via 12(S)HETE secretion; the possible role of cancer cell derived microparticle.

Science.gov (United States)

Uchide, Keiji; Sakon, Masato; Ariyoshi, Hideo; Nakamori, Syouji; Tokunaga, Masaru; Monden, Morito

2007-02-01

Cancer cell mediated vascular endothelial cell (vEC) retraction plays a pivotal role in cancer metastasis. The aim of this study is to clarify the biochemical character of vEC retraction factor derived from human breast cancer cell line, MCF-7. In order to estimate vEC retracting activity, transwell chamber assay system was employed. We first tested the effects of trypsin digestion as well as lipid extraction of culture medium (CM). Trypsin digestion of CM resulted in approximately 40% loss of vEC retracting activity and lipid extraction of CM by Brigh and Dyer methods recovered approximately 60% of vEC retracting activity, suggesting that approximately 60% of vEC retracting activity in MCF-7 derived CM is due to lipid. Although Nordihydroguaiaretic acid (NDGA), the specific lipoxygenase inhibitor, suppressed vEC retracting activity in CM, Acetyl salicylic acid (ASA), a specific cyclooxygenase inhibitor, did not affect the activity, suggesting that lipid exerting vEC retracting activity in CM belongs to lipoxygenase mediated arachidonate metabolites. Thin layer chromatography clearly demonstrated that Rf value of lipid vEC retracting factor in CM is identical to 12HETE. Authentic 12(S)HETE, but not 12(R)HETE, showed vEC retracting activity. After the ultracentrifugation of CM, most lipid vEC retracting activity was recovered from the pellet fraction, and flow cytometric analysis using specific antibody against 12(S)HETE clearly showed the association of 12(S)HETE with small particle in CM. These findings suggested the principal involvement of 12(S)HETE in cancer cell derived microparticles in cancer cell mediated vEC retraction.

哈氏弧菌EcGY020401优化培养%Optimization Culture of Vibrio harveyi EcGY020401

Institute of Scientific and Technical Information of China (English)

陶家发; 赖迎迢; 潘厚军; 石存斌; 吴淑勤

2010-01-01

目的:为规模化制备弧菌疫苗提供相关数据.方法:利用摇瓶和小型发酵罐培养,通过平板计数测定培养菌液的活菌数.结果:哈氏弧菌(Vibrio harveyi)EcGY020401株最适盐度为20～25g/L,合适的pH为7.5～7.7,葡萄糖浓度最适浓度为2～5g/L,用TSB优化培养基:胰蛋白胨5g/L、蛋白胨15g/L、大豆蛋白胨3g/L、酵母膏1g/L、葡萄糖4g/L、磷酸氢二钾5g/L、氯化钠15g/L、pH 7.5,培养EcGY020401菌株,可达2.95×1010 cfu/mL;小型发酵罐培养,10h可达到生长最大值,菌液浓度为3.46×1010cfu/mL 结论:用优化TSB培养基,采用发酵罐培养弧菌,可降低成本,提搞培养效率.

Mechanism of mRNA-STAR domain interaction: Molecular dynamics simulations of Mammalian Quaking STAR protein.

Science.gov (United States)

Sharma, Monika; Anirudh, C R

2017-10-03

STAR proteins are evolutionary conserved mRNA-binding proteins that post-transcriptionally regulate gene expression at all stages of RNA metabolism. These proteins possess conserved STAR domain that recognizes identical RNA regulatory elements as YUAAY. Recently reported crystal structures show that STAR domain is composed of N-terminal QUA1, K-homology domain (KH) and C-terminal QUA2, and mRNA binding is mediated by KH-QUA2 domain. Here, we present simulation studies done to investigate binding of mRNA to STAR protein, mammalian Quaking protein (QKI). We carried out conventional MD simulations of STAR domain in presence and absence of mRNA, and studied the impact of mRNA on the stability, dynamics and underlying allosteric mechanism of STAR domain. Our unbiased simulations results show that presence of mRNA stabilizes the overall STAR domain by reducing the structural deviations, correlating the 'within-domain' motions, and maintaining the native contacts information. Absence of mRNA not only influenced the essential modes of motion of STAR domain, but also affected the connectivity of networks within STAR domain. We further explored the dissociation of mRNA from STAR domain using umbrella sampling simulations, and the results suggest that mRNA binding to STAR domain occurs in multi-step: first conformational selection of mRNA backbone conformations, followed by induced fit mechanism as nucleobases interact with STAR domain.

Consumption of food in EC countries

International Nuclear Information System (INIS)

Ven-Breken, T.J. van de; Brenot, J.; Bonnefous, S.; Noordijk, H.; Leenhouts, H.P.

1990-08-01

Annual consumption of 10 classes of food and drink is reported for the total population of each EC-country. National food consumption data are generalized by distinguishing groups of countries with similar diet. Group 1: UK and Ireland (low consumption of fruit, high consumption of potatoes and fresh dairy products). Group 2: Italy and Greece (high consumption of cereals, vegetables and fruit, low consumption of fresh dairy products). Group 3: France, Belgium, Luxembourg, Netherlands, FRG and Spain (intermediate consumption of most foodstuffs). Portugal and Denmark could not be classified in any group. Changes in food consumption related to differences in age, sex, social class, regional habits and level of urbanisation are reported.In some cases, variation of annual food consumption over the different seasons on the relative contribution of food from local origin to the total diet, could be estimated. Differences of region, age and level of urbanisation appear to have the largest influence on consumed amounts. As for age, the values for the different age-groups range from 50 to 80 percent of the adult diet. Regional consumption may diverge from 70-130 percent of the average national consumption, with values of 200 percent for potatoes and fruit. Consumption in urban areas compared with the entire country diverges from 70-100 percent. In rural areas the values diverge from 100-140 percent. Self-support of vegetables and milk seems to be important for most countries. Of the other products, self-support of wheat and cheese is only of importance in the south of the EC. When combining the effects of the different factors, a range of consumed amounts for specific population groups of 50 to 200 percent of the average national consumption was determined. (author). 38 refs.; 13 figs.; 75 tabs

Making star teams out of star players.

Science.gov (United States)

Mankins, Michael; Bird, Alan; Root, James

2013-01-01

Top talent is an invaluable asset: In highly specialized or creative work, for instance, "A" players are likely to be six times as productive as "B" players. So when your company has a crucial strategic project, why not multiply all that firepower and have a team of your best performers tackle it? Yet many companies hesitate to do this, believing that all-star teams don't work: Big egos will get in the way. The stars won't be able to work with one another. They'll drive the team Leader crazy. Mankins, Bird, and Root of Bain & Company believe it's time to set aside that thinking. They have seen all-star teams do extraordinary work. But there is a right way and a wrong way to organize them. Before you can even begin to assemble such a team, you need to have the right talent management practices, so you hire and develop the best people and know what they're capable of. You have to give the team appropriate incentives and leaders and support staffers who are stars in their own right. And projects that are ill-defined or small scale are not for all-star teams. Use them only for critical missions, and make sure their objectives are clear. Even with the right setup, things can still go wrong. The wise executive will take steps to manage egos, prune non-team-players, and prevent average coworkers from feeling completely undervalued. She will also invest a lot of time in choosing the right team Leader and will ask members for lots of feedback to monitor how that leader is doing.

Strangeon and Strangeon Star

Science.gov (United States)

Xiaoyu, Lai; Renxin, Xu

2017-06-01

The nature of pulsar-like compact stars is essentially a central question of the fundamental strong interaction (explained in quantum chromo-dynamics) at low energy scale, the solution of which still remains a challenge though tremendous efforts have been tried. This kind of compact objects could actually be strange quark stars if strange quark matter in bulk may constitute the true ground state of the strong-interaction matter rather than 56Fe (the so-called Witten’s conjecture). From astrophysical points of view, however, it is proposed that strange cluster matter could be absolutely stable and thus those compact stars could be strange cluster stars in fact. This proposal could be regarded as a general Witten’s conjecture: strange matter in bulk could be absolutely stable, in which quarks are either free (for strange quark matter) or localized (for strange cluster matter). Strange cluster with three-light-flavor symmetry is renamed strangeon, being coined by combining “strange nucleon” for the sake of simplicity. A strangeon star can then be thought as a 3-flavored gigantic nucleus, and strangeons are its constituent as an analogy of nucleons which are the constituent of a normal (micro) nucleus. The observational consequences of strangeon stars show that different manifestations of pulsarlike compact stars could be understood in the regime of strangeon stars, and we are expecting more evidence for strangeon star by advanced facilities (e.g., FAST, SKA, and eXTP).

annot8r: GO, EC and KEGG annotation of EST datasets

Directory of Open Access Journals (Sweden)

Schmid Ralf

2008-04-01

Full Text Available Abstract Background The expressed sequence tag (EST methodology is an attractive option for the generation of sequence data for species for which no completely sequenced genome is available. The annotation and comparative analysis of such datasets poses a formidable challenge for research groups that do not have the bioinformatics infrastructure of major genome sequencing centres. Therefore, there is a need for user-friendly tools to facilitate the annotation of non-model species EST datasets with well-defined ontologies that enable meaningful cross-species comparisons. To address this, we have developed annot8r, a platform for the rapid annotation of EST datasets with GO-terms, EC-numbers and KEGG-pathways. Results annot8r automatically downloads all files relevant for the annotation process and generates a reference database that stores UniProt entries, their associated Gene Ontology (GO, Enzyme Commission (EC and Kyoto Encyclopaedia of Genes and Genomes (KEGG annotation and additional relevant data. For each of GO, EC and KEGG, annot8r extracts a specific sequence subset from the UniProt dataset based on the information stored in the reference database. These three subsets are then formatted for BLAST searches. The user provides the protein or nucleotide sequences to be annotated and annot8r runs BLAST searches against these three subsets. The BLAST results are parsed and the corresponding annotations retrieved from the reference database. The annotations are saved both as flat files and also in a relational postgreSQL results database to facilitate more advanced searches within the results. annot8r is integrated with the PartiGene suite of EST analysis tools. Conclusion annot8r is a tool that assigns GO, EC and KEGG annotations for data sets resulting from EST sequencing projects both rapidly and efficiently. The benefits of an underlying relational database, flexibility and the ease of use of the program make it ideally suited for non

Rotating Stars in Relativity

Directory of Open Access Journals (Sweden)

Stergioulas Nikolaos

2003-01-01

Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

Wave Star

DEFF Research Database (Denmark)

Kramer, Morten; Brorsen, Michael; Frigaard, Peter

Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

Four new Delta Scuti stars

Science.gov (United States)

Schutt, R. L.

1991-01-01

Four new Delta Scuti stars are reported. Power, modified into amplitude, spectra, and light curves are used to determine periodicities. A complete frequency analysis is not performed due to the lack of a sufficient time base in the data. These new variables help verify the many predictions that Delta Scuti stars probably exist in prolific numbers as small amplitude variables. Two of these stars, HR 4344 and HD 107513, are possibly Am stars. If so, they are among the minority of variable stars which are also Am stars.

Design and DSP implementation of star image acquisition and star point fast acquiring and tracking

Science.gov (United States)

Zhou, Guohui; Wang, Xiaodong; Hao, Zhihang

2006-02-01

Star sensor is a special high accuracy photoelectric sensor. Attitude acquisition time is an important function index of star sensor. In this paper, the design target is to acquire 10 samples per second dynamic performance. On the basis of analyzing CCD signals timing and star image processing, a new design and a special parallel architecture for improving star image processing are presented in this paper. In the design, the operation moving the data in expanded windows including the star to the on-chip memory of DSP is arranged in the invalid period of CCD frame signal. During the CCD saving the star image to memory, DSP processes the data in the on-chip memory. This parallelism greatly improves the efficiency of processing. The scheme proposed here results in enormous savings of memory normally required. In the scheme, DSP HOLD mode and CPLD technology are used to make a shared memory between CCD and DSP. The efficiency of processing is discussed in numerical tests. Only in 3.5ms is acquired the five lightest stars in the star acquisition stage. In 43us, the data in five expanded windows including stars are moved into the internal memory of DSP, and in 1.6ms, five star coordinates are achieved in the star tracking stage.

A new verification film system for routine quality control of radiation fields: Kodak EC-L.

Science.gov (United States)

Hermann, A; Bratengeier, K; Priske, A; Flentje, M

2000-06-01

The use of modern irradiation techniques requires better verification films for determining set-up deviations and patient movements during the course of radiation treatment. This is an investigation of the image quality and time requirement of a new verification film system compared to a conventional portal film system. For conventional verifications we used Agfa Curix HT 1000 films which were compared to the new Kodak EC-L film system. 344 Agfa Curix HT 1000 and 381 Kodak EC-L portal films of different tumor sites (prostate, rectum, head and neck) were visually judged on a light box by 2 experienced physicians. Subjective judgement of image quality, masking of films and time requirement were checked. In this investigation 68% of 175 Kodak EC-L ap/pa-films were judged "good", only 18% were classified "moderate" or "poor" 14%, but only 22% of 173 conventional ap/pa verification films (Agfa Curix HT 1000) were judged to be "good". The image quality, detail perception and time required for film inspection of the new Kodak EC-L film system was significantly improved when compared with standard portal films. They could be read more accurately and the detection of set-up deviation was facilitated.

Orbiting radiation stars

International Nuclear Information System (INIS)

Foster, Dean P; Langford, John; Perez-Giz, Gabe

2016-01-01

We study a spherically symmetric solution to the Einstein equations in which the source, which we call an orbiting radiation star (OR-star), is a compact object consisting of freely falling null particles. The solution avoids quantum scale regimes and hence neither relies upon nor ignores the interaction of quantum mechanics and gravitation. The OR-star spacetime exhibits a deep gravitational well yet remains singularity free. In fact, it is geometrically flat in the vicinity of the origin, with the flat region being of any desirable scale. The solution is observationally distinct from a black hole because a photon from infinity aimed at an OR-star escapes to infinity with a time delay. (paper)

Studies with the EC-Earth seamless Earth system prediction model

NARCIS (Netherlands)

Hazeleger, W.; Bintanja, R.

2012-01-01

EC-Earth is a new Earth System Model (ESM) based on the operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF). Climate and weather forecasting applications share a common ancestry and are build on the same physical principles. The emerging concept of

Accreting neutron stars, black holes, and degenerate dwarf stars.

Science.gov (United States)

Pines, D

1980-02-08

During the past 8 years, extended temporal and broadband spectroscopic studies carried out by x-ray astronomical satellites have led to the identification of specific compact x-ray sources as accreting neutron stars, black holes, and degenerate dwarf stars in close binary systems. Such sources provide a unique opportunity to study matter under extreme conditions not accessible in the terrestrial laboratory. Quantitative theoretical models have been developed which demonstrate that detailed studies of these sources will lead to a greatly increased understanding of dense and superdense hadron matter, hadron superfluidity, high-temperature plasma in superstrong magnetic fields, and physical processes in strong gravitational fields. Through a combination of theory and observation such studies will make possible the determination of the mass, radius, magnetic field, and structure of neutron stars and degenerate dwarf stars and the identification of further candidate black holes, and will contribute appreciably to our understanding of the physics of accretion by compact astronomical objects.

Impurity analysis in EC-99mTC radiotracer using chromatographic techniques

International Nuclear Information System (INIS)

Almeida, E.V.; Fukumori, N.T.O.; Mengatti, J.; Silva, C.P.G.; Matsuda, M.M.N.

2008-01-01

The objective of this study was to develop two chromatographic methods of impurity analysis in radiotracer 99m Tc-EC: the Thin Layer Chromatography (TLC) and the High Performance Liquid Chromatography Reversed Phase (HPLC-RP)

Search for OB stars running away from young star clusters. I. NGC 6611

Science.gov (United States)

Gvaramadze, V. V.; Bomans, D. J.

2008-11-01

N-body simulations have shown that the dynamical decay of the young (~1 Myr) Orion Nebula cluster could be responsible for the loss of at least half of its initial content of OB stars. This result suggests that other young stellar systems could also lose a significant fraction of their massive stars at the very beginning of their evolution. To confirm this expectation, we used the Mid-Infrared Galactic Plane Survey (completed by the Midcourse Space Experiment satellite) to search for bow shocks around a number of young (⪉several Myr) clusters and OB associations. We discovered dozens of bow shocks generated by OB stars running away from these stellar systems, supporting the idea of significant dynamical loss of OB stars. In this paper, we report the discovery of three bow shocks produced by O-type stars ejected from the open cluster NGC 6611 (M16). One of the bow shocks is associated with the O9.5Iab star HD165319, which was suggested to be one of “the best examples for isolated Galactic high-mass star formation” (de Wit et al. 2005, A&A, 437, 247). Possible implications of our results for the origin of field OB stars are discussed.

Serum antibodies and DNA indicate a high prevalence of equine papillomavirus 2 (EcPV2) among horses in Switzerland.

Science.gov (United States)

Fischer, Nina M; Favrot, Claude; Birkmann, Katharina; Jackson, Michele; Schwarzwald, Colin C; Müller, Martin; Tobler, Kurt; Geisseler, Marco; Lange, Christian E

2014-06-01

The DNA of equine papillomavirus type 2 (EcPV2) is consistently found in equine papillomas and squamous cell carcinomas, indicating a causal association of EcPV2 in the pathogenesis of these tumours; however, little is known about the prevalence of this virus. The aim of this study was to determine the geno- and seroprevalence of EcPV2 in clinically healthy horses in Switzerland. Fifty horses presented to the equine department of the university clinic, displaying no skin or mucous membrane lesions or severe signs of other diseases, were sampled. Cytobrush samples from the penis or vulva and serum samples were collected. To determine the genoprevalence of EcPV2, DNA was extracted from cytobrush samples and tested for viral DNA with a PCR assay amplifying a 338 bp fragment of the E7/E1 region of the viral genome. Seroprevalence was tested using an enzyme-linked immunosorbent assay aimed to detect antibodies against the major capsid protein (L1) of EcPV2. In five of 50 horses (10%), EcPV2-specific DNA was amplified but no antibodies could be detected, whereas in 14 of 50 horses (28%), antibodies against EcPV2 but no DNA were demonstrated. Both antibodies and viral DNA were detected in four of 50 horses (8%). Neither antibodies nor viral DNA were found in 27 of 50 horses (54%). The seroprevalence suggests that EcPV2 is prevalent in the Swiss equine population, while the genoprevalence indicates that currently ongoing infections are less common. The discrepancy between geno- and seroprevalence probably indicates different stages of infection in the tested cohort. © 2014 ESVD and ACVD.

Spectrophotometry of Symbiotic Stars (Abstract)

Science.gov (United States)

Boyd, D.

2017-12-01

(Abstract only) Symbiotic stars are fascinating objects - complex binary systems comprising a cool red giant star and a small hot object, often a white dwarf, both embedded in a nebula formed by a wind from the giant star. UV radiation from the hot star ionizes the nebula, producing a range of emission lines. These objects have composite spectra with contributions from both stars plus the nebula and these spectra can change on many timescales. Being moderately bright, they lend themselves well to amateur spectroscopy. This paper describes the symbiotic star phenomenon, shows how spectrophotometry can be used to extract astrophysically useful information about the nature of these systems, and gives results for three symbiotic stars based on the author's observations.

BINARY DISRUPTION BY MASSIVE BLACK HOLES: HYPERVELOCITY STARS, S STARS, AND TIDAL DISRUPTION EVENTS

Energy Technology Data Exchange (ETDEWEB)

Bromley, Benjamin C. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Rm 201, Salt Lake City, UT 84112 (United States); Kenyon, Scott J.; Geller, Margaret J.; Brown, Warren R., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu, E-mail: mgeller@cfa.harvard.edu, E-mail: wbrown@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-04-20

We examine whether disrupted binary stars can fuel black hole growth. In this mechanism, tidal disruption produces a single hypervelocity star (HVS) ejected at high velocity and a former companion star bound to the black hole. After a cluster of bound stars forms, orbital diffusion allows the black hole to accrete stars by tidal disruption at a rate comparable to the capture rate. In the Milky Way, HVSs and the S star cluster imply similar rates of 10{sup -5} to 10{sup -3} yr{sup -1} for binary disruption. These rates are consistent with estimates for the tidal disruption rate in nearby galaxies and imply significant black hole growth from disrupted binaries on 10 Gyr timescales.

Fast pulsars, strange stars

International Nuclear Information System (INIS)

Glendenning, N.K.

1990-02-01

The initial motivation for this work was the reported discovery in January 1989 of a 1/2 millisecond pulsar in the remnant of the spectacular supernova, 1987A. The status of this discovery has come into grave doubt as of data taken by the same group in February, 1990. At this time we must consider that the millisecond signal does not belong to the pulsar. The existence of a neutron star in remnant of the supernova is suspected because of recent observations on the light curve of the remnant, and of course by the neutrino burst that announced the supernova. However its frequency is unknown. I can make a strong case that a pulsar rotation period of about 1 ms divides those that can be understood quite comfortably as neutron stars, and those that cannot. What we will soon learn is whether there is an invisible boundary below which pulsar periods do not fall, in which case, all are presumable neutron stars, or whether there exist sub- millisecond pulsars, which almost certainly cannot be neutron stars. Their most plausible structure is that of a self-bound star, a strange-quark-matter star. The existence of such stars would imply that the ground state of the strong interaction is not, as we usually assume, hadronic matter, but rather strange quark matter. Let us look respectively at stars that are bound only by gravity, and hypothetical stars that are self-bound, for which gravity is so to speak, icing on the cake

Wolf-Rayet Stars

Science.gov (United States)

Hamann, Wolf-Rainer; Sander, Andreas; Todt, Helge

Nearly 150 years ago, the French astronomers Charles Wolf and Georges Rayet described stars with very conspicuous spectra that are dominated by bright and broad emission lines. Meanwhile termed Wolf-Rayet Stars after their discoverers, those objects turned out to represent important stages in the life of massive stars. As the first conference in a long time that was specifically dedicated to Wolf-Rayet stars, an international workshop was held in Potsdam, Germany, from 1.-5. June 2015. About 100 participants, comprising most of the leading experts in the field as well as as many young scientists, gathered for one week of extensive scientific exchange and discussions. Considerable progress has been reported throughout, e.g. on finding such stars, modeling and analyzing their spectra, understanding their evolutionary context, and studying their circumstellar nebulae. While some major questions regarding Wolf-Rayet stars still remain open 150 years after their discovery, it is clear today that these objects are not just interesting stars as such, but also keystones in the evolution of galaxies. These proceedings summarize the talks and posters presented at the Potsdam Wolf-Rayet workshop. Moreover, they also include the questions, comments, and discussions emerging after each talk, thereby giving a rare overview not only about the research, but also about the current debates and unknowns in the field. The Scientific Organizing Committee (SOC) included Alceste Bonanos (Athens), Paul Crowther (Sheffield), John Eldridge (Auckland), Wolf-Rainer Hamann (Potsdam, Chair), John Hillier (Pittsburgh), Claus Leitherer (Baltimore), Philip Massey (Flagstaff), George Meynet (Geneva), Tony Moffat (Montreal), Nicole St-Louis (Montreal), and Dany Vanbeveren (Brussels).

Low-mass stars with mass loss and low-luminosity carbon star formation

International Nuclear Information System (INIS)

Boothroyd, A.I.

1987-01-01

The effects of large carbon enrichments in static stellar envelopes were investigated, using new Los Alamos opacities (including low-temperature carbon and molecular opacities) and including carbon ionizations. To search for the production of low-mass,low-luminosity carbon stars, detailed stellar evolutionary computations were carried out for a grid of low-mass stars of two different metallicities. The stars were evolved from the main sequence through all intermediate stages and through helium-shell flashes on the asymptotic giant branch. The effects of the latest nuclear reaction rates, the new Los Alamos opacities, Reimers-type wind mass loss, and detailed treatment of convection and semi-convection were investigated. Two low-luminosity carbon stars were achieved, in excellent agreement with observations. Conditions favoring dredge-up (and thus carbon-star production) include a reasonably large convective mixing length, low metallicity, relatively large envelope mass, and high flash strength. Mass loss was of major importance, tending to oppose dredge-up; the total mass-loss amounts inferred from observations suffice to prevent formation of high-mass, high-luminosity carbon stars

Spectroscopic survey of Kepler stars - II. FIES/NOT observations of A- and F-type stars

Science.gov (United States)

Niemczura, E.; Polińska, M.; Murphy, S. J.; Smalley, B.; Kołaczkowski, Z.; Jessen-Hansen, J.; Uytterhoeven, K.; Lykke, J. M.; Triviño Hage, A.; Michalska, G.

2017-09-01

We have analysed high-resolution spectra of 28 A and 22 F stars in the Kepler field, observed using the Fibre-Fed Échelle Spectrograph at the Nordic Optical Telescope. We provide spectral types, atmospheric parameters and chemical abundances for 50 stars. Balmer, Fe I and Fe II lines were used to derive effective temperatures, surface gravities and microturbulent velocities. We determined chemical abundances and projected rotational velocities using a spectrum synthesis technique. Effective temperatures calculated by spectral energy distribution fitting are in good agreement with those determined from the spectral line analysis. The stars analysed include chemically peculiar stars of the Am and λ Boo types, as well as stars with approximately solar chemical abundances. The wide distribution of projected rotational velocity, vsin I, is typical for A and F stars. The microturbulence velocities obtained are typical for stars in the observed temperature and surface gravity ranges. Moreover, we affirm the results of Niemczura et al. that Am stars do not have systematically higher microturbulent velocities than normal stars of the same temperature.

Another Possibility for Boyajian's Star

Science.gov (United States)

Kohler, Susanna

2017-07-01

The unusual light curve of the star KIC 8462852, also known as Tabbys star or Boyajians star, has puzzled us since its discovery last year. A new study now explores whether the stars missing flux is due to internal blockage rather than something outside of the star.Mysterious DipsMost explanations for the flux dips of Boyajians star rely on external factors, like this illustrated swarm of comets. [NASA/JPL-Caltech]Boyajians star shows unusual episodes of dimming in its light curve by as much as 20%, each lasting a few to tens of days and separated by periods of typically hundreds of days. In addition, archival observations show that it has gradually faded by roughly 15% over the span of the last hundred years. What could be causing both the sporadic flux dips and the long-term fading of this odd star?Explanations thus far have varied from mundane to extreme. Alien megastructures, pieces of smashed planets or comets orbiting the star, and intervening interstellar medium have all been proposed as possible explanations but these require some object external to the star. A new study by researcher Peter Foukal proposes an alternative: what if the source of the flux obstruction is the star itself?Analogy to the SunDecades ago, researchers discovered that our own stars total flux isnt as constant as we thought. When magnetic dark spots on the Suns surface block the heat transport, the Suns luminosity dips slightly. The diverted heat is redistributed in the Suns interior, becoming stored as a very small global heating and expansion of the convective envelope. When the blocking starspot is removed, the Sun appears slightly brighter than it did originally. Its luminosity then gradually relaxes, decaying back to its original value.Model of a stars flux after a 1,000-km starspot is inserted at time t = 0 and removed at time t = ts at a depth of 10,000 km in the convective zone. The stars luminosity dips, then becomes brighter than originally, and then gradually decays. [Foukal

Stability of boson stars

International Nuclear Information System (INIS)

Gleiser, M.

1988-01-01

Boson stars are gravitationally bound, spherically symmetric equilibrium configurations of cold, free, or interacting complex scalar fields phi. As these equilibrium configurations naturally present local anisotropy, it is sensible to expect departures from the well-known stability criteria for fluid stars. With this in mind, I investigate the dynamical instability of boson stars against charge-conserving, small radial perturbations. Following the method developed by Chandrasekhar, a variational base for determining the eigenfrequencies of the perturbations is found. This approach allows one to find numerically an upper bound for the central density where dynamical instability occurs. As applications of the formalism, I study the stability of equilibrium configurations obtained both for the free and for the self-interacting [with V(phi) = (λ/4)chemical bondphichemical bond 4 ] massive scalar field phi. Instabilities are found to occur not for the critical central density as in fluid stars but for central densities considerably higher. The departure from the results for fluid stars is sensitive to the coupling λ; the higher the value of λ, the more the stability properties of boson stars approach those of a fluid star. These results are linked to the fractional anisotropy at the radius of the configuration

Strange-quark-matter stars

International Nuclear Information System (INIS)

Glendenning, N.K.

1989-11-01

We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 13 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to consist of individual hadrons. We conclude that it is implausible that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, is a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation if strange matter is stable at an energy density exceeding about 5.4 times that of nuclear matter. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 34 refs., 10 figs., 1 tab

GPM GROUND VALIDATION ENVIRONMENT CANADA (EC) MANUAL PRECIPITATION MEASUREMENTS GCPEX V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation Environment Canada (EC) Manual Precipitation Measurements GCPEx dataset was collected during the GPM Cold-season Precipitation Experiment...

VLA observations of dwarf M flare stars and magnetic stars

Science.gov (United States)

Willson, R. F.; Lang, K. R.; Foster, P.

1988-01-01

The VLA has been used to search for 6 cm emission from 16 nearby dwarf M stars, leading to the detection of only one of them - Gliese 735. The dwarf M flare stars AD Leonis and YZ Canis Minoris were also monitored at 6 cm and 20 cm wavelength in order to study variability. Successive oppositely circularly polarized bursts were detected from AD Leo at 6 cm, suggesting the presence of magnetic fields of both magnetic polarities. An impulsive 20-cm burst from YZ CMi preceded slowly varying 6-cm emission. The VLA was also used, unsuccessfully, to search for 6-cm emission from 13 magnetic Ap stars, all of which exhibit kG magnetic fields. Although the Ap magnetic stars have strong dipolar magnetic fields, the failure to detect gyroresonant radiation suggests that these stars do not have hot, dense coronae. The quiescent microwave emission from GL 735 is probably due to nonthermal radiation, since unusually high (H = 50 kG or greater) surface magnetic fields are inferred under the assumption that the 6-cm radiation is the gyroresonant radiation of thermal electrons.

ECONOMIC AND LEGAL ASPECTS OF THE PLANNED DAMAGES ACTIONS FOR THE BREACHES OF EC ANTITRUST LAW

Directory of Open Access Journals (Sweden)

Elena Isac

2010-09-01

Full Text Available This paper investigates the planned damages actions for breaches of EC antitrust law in order to assess their impact on consumer welfare. It first examines the current legal situation and concurs that the European Union needs to regulate damages actions for breaches of EC antitrust law so that a higher number of consumers could be compensated for their losses. This paper then discusses the main legal provisions proposed by the Commission in the Green and in the White paper on damages actions for breaches of EC antitrust law. The analysis of these proposed legal provisions is done using arguments specific to the economic analysis of law. It is demonstrated that most of these proposed legal provisions will enhance consumer welfare but that there are also proposed legal provisions which will damage consumer welfare. The paper concludes that the planned damages actions for breaches of the EC law will be an improvement compared to the current situation. However, the Commission should amend some of the proposed legal provisions in order to help consumers further.

Little Bear’s pulsating stars: Variable star census of UMi dSph Galaxy

Directory of Open Access Journals (Sweden)

Kinemuchi K.

2017-01-01

Full Text Available Recent observations and a photometric search for variable stars in the Ursa Minor dwarf spheroidal galaxy (UMi dSph are presented. Our observations were taken at Apache Point Observatory in 2014 and 2016 using the 0.5m ARCSAT telescope and the West Mountain Observatory (WMO 0.9m telescope of Brigham Young University in 2016. Previously known RR Lyrae stars in our field of view of the UMi dSph are identified, and we also catalog new variable star candidates. Tentative classifications are given for some of the new variable stars. We have conducted period searches with the data collected with the WMO telescope. Our ultimate goal is to create an updated catalog of variable stars in the UMi dSph and to compare the RR Lyrae stellar characteristics to other RR Lyrae stars found in the Local Group dSph galaxies.

Q and A. Why the EC's PINC has failed Europe's nuclear industry

Energy Technology Data Exchange (ETDEWEB)

Kraev, Kamen [NucNet, Brussels (Belgium)

2016-12-15

The European Economic and Social Committee (EESC) has called for a more comprehensive strategy to be incorporated in a revised version of the European Commission's (EC) Illustrative Programme for Nuclear Energy (PINC). EESC member Brian Curtis tells NucNet why the PINC has failed to address key issues for nuclear and why he believes the EC has become side-tracked by renewables. The EESC is a consultative body which represents the interests of civil society organisations and stakeholders at the EU. Its opinions are forwarded to the EC, the European Council, and the European Parliament and are considered in the EU's decision-making process. Brian Curtis was rapporteur on the committee's opinion paper.

Star Imager

DEFF Research Database (Denmark)

Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta

1997-01-01

The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol.......The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol....

Wolf-Rayet stars associated to giant regions of star formation

International Nuclear Information System (INIS)

D'Odorico, S.; Rosa, M.

1982-01-01

Data on Wolf-Rayet (WR) stars in extragalactic H II regions and emission line galaxies are presented and discussed. The sample is still limited and inhomogeneous but two important points appear to be already established: a) The WR stars are more numerous than the blue supergiants at least in same phase of the evolution of the stellar clusters which ionize the giant H II regions, b) When the WR stars are detected, two cases are apparently observed, one in which only WN, the other in which both WN and WC, are present. (Auth.)

Asteroseismology of white dwarf stars

OpenAIRE

Córsico, A. H.

2014-01-01

Most of low- and intermediate-mass stars that populate the Universe will end their lives as white dwarf stars. These ancient stellar remnants have encrypted inside a precious record of the evolutionary history of the progenitor stars, providing a wealth of information about the evolution of stars, star formation, and the age of a variety of stellar populations, such as our Galaxy and open and globular clusters. While some information like surface chemical composition, temperature and gravity ...

Towards Coleoptera-specific high-throughput screening systems for compounds with ecdysone activity: development of EcR reporter assays using weevil (Anthonomus grandis)-derived cell lines and in silico analysis of ligand binding to A. grandis EcR ligand-binding pocket.

Science.gov (United States)

Soin, Thomas; Iga, Masatoshi; Swevers, Luc; Rougé, Pierre; Janssen, Colin R; Smagghe, Guy

2009-08-01

Molting in insects is regulated by ecdysteroids and juvenile hormones. Several synthetic non-steroidal ecdysone agonists are on the market as insecticides. These ecdysone agonists are dibenzoylhydrazine (DBH) analogue compounds that manifest their toxicity via interaction with the ecdysone receptor (EcR). Of the four commercial available ecdysone agonists, three (tebufenozide, methoxyfenozide and chromafenozide) are highly lepidopteran specific, one (halofenozide) is used to control coleopteran and lepidopteran insects in turf and ornamentals. However, compared to the very high binding affinity of these DBH analogues to lepidopteran EcRs, halofenozide has a low binding affinity for coleopteran EcRs. For the discovery of ecdysone agonists that target non-lepidopteran insect groups, efficient screening systems that are based on the activation of the EcR are needed. We report here the development and evaluation of two coleopteran-specific reporter-based screening systems to discover and evaluate ecdysone agonists. The screening systems are based on the cell lines BRL-AG-3A and BRL-AG-3C that are derived from the weevil Anthonomus grandis, which can be efficiently transduced with an EcR reporter cassette for evaluation of induction of reporter activity by ecdysone agonists. We also cloned the almost full length coding sequence of EcR expressed in the cell line BRL-AG-3C and used it to make an initial in silico 3D-model of its ligand-binding pocket docked with ponasterone A and tebufenozide.

Integration of IC/EC systems in ITER

International Nuclear Information System (INIS)

Gassmann, T.; Beaumont, B.; Baruah, U.K.; Bonicelli, T.; Chiocchio, S.; Cox, D.; Darbos, C.; Decamps, H.; Denisov, G.; Henderson, M.; Kazarian, F.; Lamalle, P.U.; Mukherjee, A.; Rasmussen, D.; Saibene, G.; Sartori, R.; Sakamoto, K.; Tanga, A.

2010-01-01

The RF heating and current drive (H and CD) systems that are to be installed in ITER during the construction phase, are the electron cyclotron (EC) and ion cyclotron (IC) systems. They are complex assemblies of high voltage power supplies (HVPS), RF generators, transmission lines and antennas. Their design and integration are constrained by many interfaces, both internal, between the subsystems, and external, with the other ITER systems. In addition, some components must be compatible with a nuclear environment and are classified as Safety Important Component. This paper describes the processes implemented in ITER to ensure proper integration.

Renewables in Transport: Directive 2009/28/EC - Devils in its Details

International Nuclear Information System (INIS)

Wilkin, S.

2009-01-01

As part of the 3*20 targets reached in December 2008, the EC decided that the EU should, by 2020, source 20% of its Final Energy Consumption (FEC) renewably. Working towards this aim should in general contribute to the primary objective of reducing emissions, but there are two major issues with the implementation of the target in the Transport sector which run the risk of being irrelevant or even counterproductive. Firstly, the constraining stipulation that all Member States should source 10% of their Transport sector FEC renewably will be a struggle for some Member States to achieve, forcing them to invest large amounts of money which would be better spent elsewhere. Secondly, the relevant legislation gives unrepresentative weight to the benefits of Electric Vehicles (EVs), meaning that Member States which invest in EVs may give the illusion of having reached their national renewable targets without actually having done so. This paper is based on EC Directive 2009/28/EC (henceforth referred to as 'the Directive') and the National Renewable Energy Action Plans of Denmark, France, Germany, Italy, Spain, and the UK which were submitted in response. Each EU Member State has an individual target for the proportion of its FEC which is to come from renewable sources in 2020. The targets are based on the countries? existing renewable shares (as shown in Table 1 below) and their supposed capacity for improvement. Together, they give an average EU-wide target of 20% across the 27 Member States. (author)

Metal-poor star formation triggered by the feedback effects from Pop III stars

Science.gov (United States)

Chiaki, Gen; Susa, Hajime; Hirano, Shingo

2018-04-01

Metal enrichment by first-generation (Pop III) stars is the very first step of the matter cycle in structure formation and it is followed by the formation of extremely metal-poor (EMP) stars. To investigate the enrichment process by Pop III stars, we carry out a series of numerical simulations including the feedback effects of photoionization and supernovae (SNe) of Pop III stars with a range of masses of minihaloes (MHs), Mhalo, and Pop III stars, MPopIII. We find that the metal-rich ejecta reach neighbouring haloes and external enrichment (EE) occurs when the H II region expands before the SN explosion. The neighbouring haloes are only superficially enriched, and the metallicity of the clouds is [Fe/H] < -5. Otherwise, the SN ejecta fall back and recollapse to form an enriched cloud, i.e. an internal-enrichment (IE) process takes place. In the case where a Pop III star explodes as a core-collapse SN (CCSN), the MH undergoes IE, and the metallicity in the recollapsing region is -5 ≲ [Fe/H] ≲ -3 in most cases. We conclude that IE from a single CCSN can explain the formation of EMP stars. For pair-instability SNe (PISNe), EE takes place for all relevant mass ranges of MHs, consistent with the lack of observational signs of PISNe among EMP stars.

Spectrophotometry of carbon stars

Energy Technology Data Exchange (ETDEWEB)

Oganesyan, R.K.; Karapetyan, M.S.; Nersisyan, S.E.

1986-01-01

The results are given of the spectrophotometric investigation of 56 carbon stars in the spectral range from 4000 to 6800 A with resolution 3 A. The observed energy distributions of these stars are determined relative to the flux at the wavelength /sub 0/ = 5556; they are presented in the form of graphs. The energy distributions have been obtained for the first time for 35 stars. Variation in the line Ba II 4554 A has been found in the spectra of St Cam, UU Aur, and RV Mon. Large changes have taken place in the spectra of RT UMa and SS Vir. It is noted that the spectra of carbon stars have a depression, this being situated in different spectral regions for individual groups of stars.

The Search for New Luminous Blue Variable Stars: Near-Infrared Spectroscopy of Stars With 24 micron Shells

Science.gov (United States)

Stringfellow, Guy; Gvaramadze, Vasilii

2010-02-01

Luminous Blue Variable (LBV) stars represent an extremely rare class of very luminous and massive stars. Only about a dozen confirmed Galactic LBV stars are known to date, which precludes us from determining a solid evolutionary connection between LBV and other intermediate (e.g. Ofpe/WN9, WNL) phases in the life of very massive stars. The known LBV stars each have their own unique properties, so new discoveries add insight into the properties and evolutionary status of LBVs and massive stars; even one new discovery of objects of this type could provide break-through results in the understanding of the intermediate stages of massive star evolution. We have culled a prime sample of possible LBV candidates from the Spitzer 24 (micron) archival data. All have circumstellar nebulae, rings, and shells (typical of LBVs and related stars) surrounding reddened central stars. Spectroscopic followup of about two dozen optically visible central stars associated with the shells from this sample showed that they are either candidate LBVs, late WN-type Wolf-Rayet stars or blue supergiants. We propose infrared spectroscopic observations of the central stars for a large fraction (23 stars) of our northern sample to determine their nature and discover additional LBV candidates. These stars have no plausible optical counterparts, so infrared spectra are needed. This program requires two nights of Hale time using TripleSpec.

The Stars behind the Curtain

Science.gov (United States)

2010-02-01

ESO is releasing a magnificent VLT image of the giant stellar nursery surrounding NGC 3603, in which stars are continuously being born. Embedded in this scenic nebula is one of the most luminous and most compact clusters of young, massive stars in our Milky Way, which therefore serves as an excellent "local" analogue of very active star-forming regions in other galaxies. The cluster also hosts the most massive star to be "weighed" so far. NGC 3603 is a starburst region: a cosmic factory where stars form frantically from the nebula's extended clouds of gas and dust. Located 22 000 light-years away from the Sun, it is the closest region of this kind known in our galaxy, providing astronomers with a local test bed for studying intense star formation processes, very common in other galaxies, but hard to observe in detail because of their great distance from us. The nebula owes its shape to the intense light and winds coming from the young, massive stars which lift the curtains of gas and clouds revealing a multitude of glowing suns. The central cluster of stars inside NGC 3603 harbours thousands of stars of all sorts (eso9946): the majority have masses similar to or less than that of our Sun, but most spectacular are several of the very massive stars that are close to the end of their lives. Several blue supergiant stars crowd into a volume of less than a cubic light-year, along with three so-called Wolf-Rayet stars - extremely bright and massive stars that are ejecting vast amounts of material before finishing off in glorious explosions known as supernovae. Using another recent set of observations performed with the SINFONI instrument on ESO's Very Large Telescope (VLT), astronomers have confirmed that one of these stars is about 120 times more massive than our Sun, standing out as the most massive star known so far in the Milky Way [1]. The clouds of NGC 3603 provide us with a family picture of stars in different stages of their life, with gaseous structures that are

[Knockdown of NEDD9 inhibits the proliferation, invasion and migration of esophageal carcinoma EC109 cells].

Science.gov (United States)

Zhang, Wen; Li, Shaojun; Zhao, Yunlong; Guo, Nannan; Li, Yingjie

2016-12-01

Objective To observe the expression of the neural precursor cell expressed, developmentally down-regulated 9 (NEDD9) in esophageal cancer, to investigate the impact of decreased expression of NEDD9 on invasion and migration, and to explicit the function of NEDD9 in EC109 human esophageal cancer cell line. Methods Immunohistochemical staining was used to detect the expression of NEDD9 in human esophageal cancer tissues and paracancerous normal tissues. RNA interfering (RNAi) was used to knockdown NEDD9 in EC109 cells. The interference efficiency was detected by reverse transcription PCR (RT-PCR) and Western blot analysis. Cell proliferation was determined by MTT assay and the invasion and migration abilities of EC109 cells were monitored by Transwell TM assay. The protein levels of proliferating cell nuclear antigen (PCNA), Bax and Bcl-2 were tested by Western blotting. Results The positive expression rate of NEDD9 in esophageal carcinoma tissues was significantly higher compared with that in the paracancerous tissues. After NEDD9 expression was successfully downregulated in EC109 cells by siRNA, the proliferation, invasion and migration rates in transfection group were significantly lower than those in control group; meanwhile, the expression of Bcl-2 was reduced and Bax expression was enhanced. Conclusion The protein expression level of NEDD9 is higher in esophageal carcinoma tissues than that in adjacent normal tissues. Knockdown of NEDD9 expression can restrain the proliferation, invasion and migration of EC109 cells.

(EC+β+) decay of 130Ce

International Nuclear Information System (INIS)

Xu Shuwei; Zhang Tianmei; Xie Yuanxiang; Ma Ruichang; Ge Yuanxiu; Guo Yingxiang; Wang Chunfang; Li Zhankui; Guo Bing; Xing Jianping; Guo Tianrui; Zhu Shaofei; Xu Wang; Du Jinzhou

1996-01-01

The nuclide 130 Ce was produced by a ( 16 O, 4n) reaction on an enriched 118 Sn target. Reaction products were transported to a shielded location by using a helium-jet tape transport system. A 22.9 min activity in chemically separated cerium sample was identified as 130 Ce. The (EC+β + ) decay scheme of 130 Ce was proposed for the first time. This scheme includes 108 γ-lines, 107 γ-lines among them being new. More than 13 1 + low-lying states of 130 La are populated in the decay of 130 Ce. Two new isomers with half-life of 77±10 ns and 17±5 ns were observed by means of delayed γ-γ coincidence measurements. (orig.). With 5 figs., 3 tabs

CHEMICAL AND KINEMATICAL PROPERTIES OF BLUE STRAGGLER STARS AND HORIZONTAL BRANCH STARS IN NGC 6397

International Nuclear Information System (INIS)

Lovisi, L.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Dalessandro, E.; Contreras Ramos, R.; Gratton, R.

2012-01-01

We used three sets of high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 42 horizontal branch (HB) stars, 18 blue straggler stars (BSSs), and 86 main-sequence (MS) turnoff (TO) and sub-giant branch stars in the nearby globular cluster NGC 6397. We measured rotational velocities and Fe, O, and Mg abundances. All of the unevolved stars in our sample have low rotational velocites (vsin i –1 ), while the HB stars and BSSs show a broad distribution, with values ranging from 0 to ∼70 km s –1 . For HB stars with T 8200 K and T > 10,500 K, respectively) also show significant deviations in their iron abundance with respect to the cluster metallicity (as traced by the unevolved stars, [Fe/H] = –2.12). While similar chemical patterns have already been observed in other hot HB stars, this is the first evidence ever collected for BSSs. We interpret these abundance anomalies as due to the metal radiative levitation, occurring in stars with shallow or no convective envelopes.

A new verification film system for routine quality control of radiation fields: Kodak EC-L

International Nuclear Information System (INIS)

Hermann, A.; Bratengeier, K.; Priske, A.; Flentje, M.

2000-01-01

Background: The use of modern irradiation techniques requires better verification films for determining set-up deviations and patient movements during the course of radiation treatment. This is an investigation of the image quality and time requirement of a new verification film system compared to a conventional portal film system. Material and Methods: For conventional verifications we used Agfa Curix HT 1000 films which were compared to the new Kodak EC-L film system. 344 Agfa Curix HT 1000 and 381 Kodak EC-L portal films of different tumor sites (prostate, rectum, head and neck) were visually judged on a light box by 2 experienced physicians. Subjective judgement of image quality, masking of films and time requirement were checked. Results: In this investigation 68% of 175 Kodak EC-L ap/pa-films were judged 'good', only 18% were classified 'moderate' or 'poor' 14%, but only 22% of 173 conventional ap/pa verification films (Agfa Curix HT 1000) were judged to be 'good'. Conclusions: The image quality, detail perception and time required for film inspection of the new Kodak EC-L film system was significantly improved when compared with standard portal films. They could be read more accurately and the detection of set-up deviation was facilitated. (orig.) [de

Hierarchical Star Formation in Turbulent Media: Evidence from Young Star Clusters

Energy Technology Data Exchange (ETDEWEB)

Grasha, K.; Calzetti, D. [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Elmegreen, B. G. [IBM Research Division, T.J. Watson Research Center, Yorktown Heights, NY (United States); Adamo, A.; Messa, M. [Department of Astronomy, The Oskar Klein Centre, Stockholm University, Stockholm (Sweden); Aloisi, A.; Bright, S. N.; Lee, J. C.; Ryon, J. E.; Ubeda, L. [Space Telescope Science Institute, Baltimore, MD (United States); Cook, D. O. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY (United States); Fumagalli, M. [Institute for Computational Cosmology and Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham (United Kingdom); Gallagher III, J. S. [Department of Astronomy, University of Wisconsin–Madison, Madison, WI (United States); Gouliermis, D. A. [Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120, Heidelberg (Germany); Kahre, L. [Department of Astronomy, New Mexico State University, Las Cruces, NM (United States); Kim, H. [Gemini Observatory, La Serena (Chile); Krumholz, M. R., E-mail: kgrasha@astro.umass.edu [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia)

2017-06-10

We present an analysis of the positions and ages of young star clusters in eight local galaxies to investigate the connection between the age difference and separation of cluster pairs. We find that star clusters do not form uniformly but instead are distributed so that the age difference increases with the cluster pair separation to the 0.25–0.6 power, and that the maximum size over which star formation is physically correlated ranges from ∼200 pc to ∼1 kpc. The observed trends between age difference and separation suggest that cluster formation is hierarchical both in space and time: clusters that are close to each other are more similar in age than clusters born further apart. The temporal correlations between stellar aggregates have slopes that are consistent with predictions of turbulence acting as the primary driver of star formation. The velocity associated with the maximum size is proportional to the galaxy’s shear, suggesting that the galactic environment influences the maximum size of the star-forming structures.

620 ASSESSMENT OF HEAVY METALS, pH AND EC IN EFFLUENT ...

African Journals Online (AJOL)

Osondu

evaluated metals were Cu, Fe, Ni, Mn, Cr, Zn, Cd, Co, and Ag. The pH, EC, TDS, DO ... heavy metals, but the high heavy metal concentrations in the soil could seriously ... Key words: Heavy metals, AAS, contamination, floriculture and effluents.

PROGRESSIVE STAR FORMATION IN THE YOUNG GALACTIC SUPER STAR CLUSTER NGC 3603

International Nuclear Information System (INIS)

Beccari, Giacomo; Spezzi, Loredana; De Marchi, Guido; Andersen, Morten; Paresce, Francesco; Young, Erick; Panagia, Nino; Bond, Howard; Balick, Bruce; Calzetti, Daniela; Carollo, C. Marcella; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; O'Connell, Robert W.; Saha, Abhijit

2010-01-01

Early Release Science observations of the cluster NGC 3603 with the WFC3 on the refurbished Hubble Space Telescope allow us to study its recent star formation history. Our analysis focuses on stars with Hα excess emission, a robust indicator of their pre-main sequence (PMS) accreting status. The comparison with theoretical PMS isochrones shows that 2/3 of the objects with Hα excess emission have ages from 1 to 10 Myr, with a median value of 3 Myr, while a surprising 1/3 of them are older than 10 Myr. The study of the spatial distribution of these PMS stars allows us to confirm their cluster membership and to statistically separate them from field stars. This result establishes unambiguously for the first time that star formation in and around the cluster has been ongoing for at least 10-20 Myr, at an apparently increasing rate.

Carbon Stars T. Lloyd Evans

Indian Academy of Sciences (India)

that the features used in estimating luminosities of ordinary giant stars are just those whose abundance ... This difference between the spectral energy distributions (SEDs) of CH stars and the. J stars, which belong to .... that the first group was binaries, as for the CH stars of the solar vicinity, while those of the second group ...

The Spacelab IPS Star Simulator

Science.gov (United States)

Wessling, Francis C., III

The cost of doing business in space is very high. If errors occur while in orbit the costs grow and desired scientific data may be corrupted or even lost. The Spacelab Instrument Pointing System (IPS) Star Simulator is a unique test bed that allows star trackers to interface with simulated stars in a laboratory before going into orbit. This hardware-in-the loop testing of equipment on earth increases the probability of success while in space. The IPS Star Simulator provides three fields of view 2.55 x 2.55 degrees each for input into star trackers. The fields of view are produced on three separate monitors. Each monitor has 4096 x 4096 addressable points and can display 50 stars (pixels) maximum at a given time. The pixel refresh rate is 1000 Hz. The spectral output is approximately 550 nm. The available relative visual magnitude range is 2 to 8 visual magnitudes. The star size is less than 100 arc seconds. The minimum star movement is less than 5 arc seconds and the relative position accuracy is approximately 40 arc seconds. The purpose of this paper is to describe the LPS Star Simulator design and to provide an operational scenario so others may gain from the approach and possible use of the system.

Rotating stars in relativity.

Science.gov (United States)

Paschalidis, Vasileios; Stergioulas, Nikolaos

2017-01-01

Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f -modes and r -modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

Ecology of blue straggler stars

CERN Document Server

Carraro, Giovanni; Beccari, Giacomo

2015-01-01

The existence of blue straggler stars, which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution. Such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. They are found to exist in globular clusters, open clusters, dwarf spheroidal galaxies of the Local Group, OB associations and as field stars. This book summarises the many advances in observational and theoretical work dedicated to blue straggler stars. Carefully edited extended contributions by well-known experts in the field cover all the relevant aspects of blue straggler stars research: Observations of blue straggler stars in their various environments; Binary stars and formation channels; Dynamics of globular clusters; Interpretation of observational data and comparison with models. The book also offers an introductory chapter on stellar evolution written by the editors of the book.

What Determines Star Formation Rates?

Science.gov (United States)

Evans, Neal John

2017-06-01

The relations between star formation and gas have received renewed attention. We combine studies on scales ranging from local (within 0.5 kpc) to distant galaxies to assess what factors contribute to star formation. These include studies of star forming regions in the Milky Way, the LMC, nearby galaxies with spatially resolved star formation, and integrated galaxy studies. We test whether total molecular gas or dense gas provides the best predictor of star formation rate. The star formation ``efficiency," defined as star formation rate divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all the molecular gas. We suggest ways to further develop the concept of "dense gas" to incorporate other factors, such as turbulence.

Mass loss from S stars

International Nuclear Information System (INIS)

Jura, M.

1988-01-01

The mass-loss process in S stars is studied using 65 S stars from the listing of Wing and Yorka (1977). The role of pulsations in the mass-loss process is examined. It is detected that stars with larger mass-loss rates have a greater amplitude of pulsations. The dust-to-gas ratio for the S stars is estimated as 0.002 and the average mass-loss rate is about 6 x 10 to the -8th solar masses/yr. Some of the properties of the S stars, such as scale height, surface density, and lifetime, are measured. It is determined that scale height is 200 pc; the total duration of the S star phase is greater than or equal to 30,000 yr; and the stars inject 3 x 10 to the -6th solar masses/sq kpc yr into the interstellar medium. 46 references

Analysis of Well ER-EC-7 Testing, Western Pahute Mesa - Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-7 during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program was documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-7 Data Report for Development and Hydraulic Testing.

Analysis of Well ER-EC-8 testing, Western Pahute Mesa-Oasis Valley FY 2000 testing program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-8 during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa-Oasis Valley, Well ER-EC-8 Data Report for development and Hydraulic Testing.

Analysis of Well ER-EC-4 Testing, Western Pahute Mesa-Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-4 during the Western Pahute Mesa-Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-4 Data Report for Development and Hydraulic Testing.

Analysis of Well ER-EC-5 Testing, Western Pahute Mesa-Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-5 during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-5 Data Report for Development and Hydraulic Testing.

Analysis of Well ER-EC-6 Testing, Western Pahute Mesa - Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-6 during the Western Pahute Mesa-Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa-Oasis Valley, Well ER-EC-6 Data Report for Development and Hydraulic Testing.

Analysis of Well ER-EC-1 Testing, Western Pahute Mesa-Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-1 during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-1 Data Report for Development and Hydraulic Testing.

76 FR 55122 - Distribution of the 2009 Cable Royalty Funds

Science.gov (United States)

2011-09-06

... such royalty fees has a reasonable objection to the proposed distribution. Consequently, this Notice... LIBRARY OF CONGRESS Copyright Royalty Board [Docket No. 2011-7 CRB CD 2009] Distribution of the 2009 Cable Royalty Funds AGENCY: Copyright Royalty Board, Library of Congress. ACTION: Notice...

On the co-existence of chemically peculiar Bp stars, slowly pulsating B stars and constant B stars in the same part of the HR diagram

NARCIS (Netherlands)

Briquet, M.; Hubrig, S.; Cat, P. de; Aerts, C.C.; North, P.; Schöller, M.

2007-01-01

Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of the H-R diagram. Methods: We carry out a comparative study

Wave Star

DEFF Research Database (Denmark)

Kramer, Morten; Frigaard, Peter

Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

Capability and limits of EC policy and instruments for protection of the environment

International Nuclear Information System (INIS)

Jarass, H.D.; Neumann, L.F.; Pastowski, A.; Ruhr, H.J. von der; Schreiber, F.

1994-01-01

The authors who contributed to this compilation of studies start from different points of view in their approaches towards describing the existing (or desirable) balance between centralised and decentralised frameworks and instruments of the EC policy for protection of the environment: A total harmonisation of environmental protection standards would be inconsistent with the principles of competition and, in terms of environmental protection, would rather foster a climate tending to be hostile to innovation. The impetus given by the EC in support of free mobility in the transport sector of the internal market on the other hand ought to be flanked by mandatory ecological standards. Adhering to the economic theory of federalism would mean to decide for a high degree of decentralisation, which in turn does not seem to be altogether appropriate in view of the large scope of impact of environmental damage and the mutual ecological dependence of EC member states. A more centralised regulatory competence has to be accompanied by correspondingly strong, democratic institutions in order to fulfill the principles of constitutional law. The priority given to the principle of subsidiarity in the compromise laid down in the Treaty of Maastricht needs to be given concrete shape [de

Covering tree with stars

DEFF Research Database (Denmark)

Baumbach, Jan; Guo, Jian-Ying; Ibragimov, Rashid

2013-01-01

We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting ...

OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. I. EVIDENCE FOR MULTIPLE PROGENITORS OF CEMP-NO STARS

Energy Technology Data Exchange (ETDEWEB)

Yoon, Jinmi; Beers, Timothy C.; Placco, Vinicius M.; Rasmussen, Kaitlin C.; Carollo, Daniela [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); He, Siyu [Department of Physics, Xi’an Jiaotong University, Shaanxi, 710049 (China); Hansen, Terese T. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Roederer, Ian U. [Joint Institute for Nuclear Astrophysics-Center for the Evolution of the Elements (JINA-CEE) (United States); Zeanah, Jeff, E-mail: jinmi.yoon@nd.edu [Z Solutions, Inc., 9430 Huntcliff Trace, Atlanta, GA 30350 (United States)

2016-12-10

We investigate anew the distribution of absolute carbon abundance, A (C) = log ϵ (C), for carbon-enhanced metal-poor (CEMP) stars in the halo of the Milky Way, based on high-resolution spectroscopic data for a total sample of 305 CEMP stars. The sample includes 147 CEMP- s (and CEMP- r / s ) stars, 127 CEMP-no stars, and 31 CEMP stars that are unclassified, based on the currently employed [Ba/Fe] criterion. We confirm previous claims that the distribution of A (C) for CEMP stars is (at least) bimodal, with newly determined peaks centered on A (C) = 7.96 (the high-C region) and A (C) = 6.28 (the low-C region). A very high fraction of CEMP- s (and CEMP- r / s ) stars belongs to the high-C region, while the great majority of CEMP-no stars resides in the low-C region. However, there exists complexity in the morphology of the A (C)-[Fe/H] space for the CEMP-no stars, a first indication that more than one class of first-generation stellar progenitors may be required to account for their observed abundances. The two groups of CEMP-no stars we identify exhibit clearly different locations in the A (Na)- A (C) and A (Mg)- A (C) spaces, also suggesting multiple progenitors. The clear distinction in A (C) between the CEMP- s (and CEMP- r / s ) stars and the CEMP-no stars appears to be as successful, and likely more astrophysically fundamental, for the separation of these sub-classes as the previously recommended criterion based on [Ba/Fe] (and [Ba/Eu]) abundance ratios. This result opens the window for its application to present and future large-scale low- and medium-resolution spectroscopic surveys.

Close binary star type x-ray star and its mechanism of radiation

Energy Technology Data Exchange (ETDEWEB)

Hoshi, R [Rikkyo Univ., Tokyo (Japan). Dept. of Physics

1975-09-01

Recent progress of the study of an X-ray star is described. In 1970, the periodical emission of pulsed X-rays from Cen X-3 and Her X-1 was observed. An optically corresponding celestial object for the Cen X-3 was reported in 1973, and the mass of Cen X-3 was revised. The optical object was named after Krzeminsky. From the observed variation of luminosity, it is said that the Krzeminsky's star is deformed. This fact gave new data on the mass of the Cen X-3, and the mass is several times as large as the previously estimated value. The behavior of the Her X-1 shows four kinds of clear time variation, and indicates the characteristics of an X-ray star. The Her X-1 is an X-ray pulser the same as Cen X-3, and is a close binary star. The opposite star is known as HZ-Her, and shows weaker luminosity than the intensity of X-ray from the Her X-1. Thirty-five day period was seen in the intensity variation of X-ray. The mechanism of X-ray pulsing can be explained by material flow into a neutron star. The energy spectrum from Her X-1 is different from that from the Cen X-3. Another X-ray star, Cyg X-1, is considered to be a black hole from its X-ray spectrum.

Estrutura de comunidades em transições ambientais : lagartos no ecótono Cerrado-Amazônia

OpenAIRE

Dantas, Pedro Tourinho

2014-01-01

Os limites ecológicos desempenham um papel crucial no fluxo de espécies, de genes e 2 nutrientes entre áreas adjacentes. Os limites não apenas separam, mas também conectam 3 estas áreas, agindo como filtros de permeabilidade variável. A estrutura das comunidades 4 varia com a proximidade do ecótono e a riqueza de espécies no ecótono pode ser maior que, 5 menor que, ou intermediária entre as áreas adjacentes. Aqui, eu investigo como o ecótono 6 isola a Amazônia e o Cerrado, atuando como um fil...

Stability of the Gel Electrolyte PAN : EC : PC : LICF3SO3 towards Lithium

DEFF Research Database (Denmark)

Perera, Kumudu; Dissanayake, M.A.K.L.; Skaarup, Steen

2006-01-01

The stability of the gel electrolyte consisting of polyacrylonitrile (PAN), ethylene carbonate (EC), propylene carbonate (PC) and lithium trifluoromethanesulfonate (LiCF3SO3 – LiTF) towards metallic lithium was investigated using the time evolution of impedance plots. Symmetric cells of the form Li...... / PAN : EC : PC: LiTF / Li were assembled and impedance data were collected at room temperature for one week. A clear indication of growth of a resistive layer could be seen. The electrolyte resistance remained constant. The growth of the passivation layer became constant after first two days...

76 FR 30987 - Termination of Action and Further Monitoring in Connection With the EC-Beef Hormones Dispute

Science.gov (United States)

2011-05-27

... Connection With the EC-Beef Hormones Dispute AGENCY: Office of the United States Trade Representative. ACTION... Hormones dispute. In January 2009, the Trade Representative announced a determination to modify the list of...) in the EC-Beef Hormones dispute. The MOU provides for the EU to make phased increases in market...

Molecular characterization of EcCIPK24 gene of finger millet (Eleusine coracana) for investigating its regulatory role in calcium transport.

Science.gov (United States)

Chinchole, Mahadev; Pathak, Rajesh Kumar; Singh, Uma M; Kumar, Anil

2017-08-01

Finger millet grains contain exceptionally high levels of calcium which is much higher compared to other cereals and millets. Since calcium is an important macronutrient in human diet, it is necessary to explore the molecular basis of calcium accumulation in the seeds of finger millet. CIPK is a calcium sensor gene, having role in activating Ca 2+ exchanger protein by interaction with CBL proteins. To know the role of EcCIPK24 gene in seed Ca 2+ accumulation, sequence is retrieved from the transcriptome data of two finger millet genotypes GP1 (low Ca 2+ ) and GP45 (high Ca 2+ ), and the expression was determined through qRT-PCR. The higher expression was found in root, shoot, leaf and developing spike tissue of GP45 compared to GP1; structural analysis showed difference of nine SNPs and one extra beta sheet domain as well as differences in vacuolar localization was predicted; besides, the variation in amino acid composition among both the genotypes was also investigated. Molecular modeling and docking studies revealed that both EcCBL4 and EcCBL10 showed strong binding affinity with EcCIPK24 (GP1) compared to EcCIPK24 (GP45). It indicates a genotypic structural variation, which not only affects the affinity but also calcium transport efficiency after interaction of CIPK-CBL with calcium exchanger ( Ec CAX1b) to pull calcium in the vacuole. Based on the expression and in silico study, it can be suggested that by activating EcCAX1b protein, EcCIPK24 plays an important role in high seed Ca 2+ accumulation.

Destruction of a Magnetized Star

Science.gov (United States)

Kohler, Susanna

2017-01-01

What happens when a magnetized star is torn apart by the tidal forces of a supermassive black hole, in a violent process known as a tidal disruption event? Two scientists have broken new ground by simulating the disruption of stars with magnetic fields for the first time.The magnetic field configuration during a simulation of the partial disruption of a star. Top left: pre-disruption star. Bottom left: matter begins to re-accrete onto the surviving core after the partial disruption. Right: vortices form in the core as high-angular-momentum debris continues to accrete, winding up and amplifying the field. [Adapted from Guillochon McCourt 2017]What About Magnetic Fields?Magnetic fields are expected to exist in the majority of stars. Though these fields dont dominate the energy budget of a star the magnetic pressure is a million times weaker than the gas pressure in the Suns interior, for example they are the drivers of interesting activity, like the prominences and flares of our Sun.Given this, we can wonder what role stars magnetic fields might play when the stars are torn apart in tidal disruption events. Do the fields change what we observe? Are they dispersed during the disruption, or can they be amplified? Might they even be responsible for launching jets of matter from the black hole after the disruption?Star vs. Black HoleIn a recent study, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Michael McCourt (Hubble Fellow at UC Santa Barbara) have tackled these questions by performing the first simulations of tidal disruptions of stars that include magnetic fields.In their simulations, Guillochon and McCourt evolve a solar-mass star that passes close to a million-solar-mass black hole. Their simulations explore different magnetic field configurations for the star, and they consider both what happens when the star barely grazes the black hole and is only partially disrupted, as well as what happens when the black hole tears the star apart

Circulation of Stars

Science.gov (United States)

Boitani, P.

2016-01-01

Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

Numerical study of rotating relativistic stars

International Nuclear Information System (INIS)

Wilson, J.R.

1975-01-01

The equations of structure for rotating stars in general relativity are presented and put in a form suitable for computer calculations. The results of equilibrium calculations for supermassive stars, neutron stars, and magnetically supported stars are reported, as are calculations of collapsing, rotating, and magnetized stars in the slowly changing gravitational field approximation. (auth)

Effect of Graphene-EC on Ag NW-Based Transparent Film Heaters: Optimizing the Stability and Heat Dispersion of Films.

Science.gov (United States)

Cao, Minghui; Wang, Minqiang; Li, Le; Qiu, Hengwei; Yang, Zhi

2018-01-10

To optimize the performance of silver nanowire (Ag NW) film heaters and explore the effect of graphene on a film, we introduced poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and graphene modified with ethyl cellulose (graphene-EC) into the film. The high-quality and well-dispersed graphene-EC was synthesized from graphene obtained by electrochemical exfoliation as a precursor. The transparent film heaters were fabricated via spin-coating. With the assistance of graphene-EC, the stability of film heaters was greatly improved, and the conductivity was optimized by adjusting the Ag NW concentration. The film heaters exhibited a fast and accurate response to voltage, accompanied by excellent environmental endurance, and there was no significant performance degradation after being operated for a long period of time. These results indicate that graphene-EC plays a crucial role in optimizing film stability and heat dispersion in the film. The Ag NW/PEDOT:PSS-doped graphene-EC film heaters show a great potential in low-cost indium-tin-oxide-free flexible transparent electrodes, heating systems, and transparent film heaters.

Statistical properties of barium stars

International Nuclear Information System (INIS)

Hakkila, J.E.

1986-01-01

Barium stars are G- and K-giant stars with atmospheric excesses of s-process elements, and a broadband spectral depression in the blue portion of the spectrum. The strength of the λ4554 Ball line is used as a classification parameter known as the Barium Intensity. They have a mean absolute magnitude of 1.0 and a dispersion of 1.2 magnitudes (assuming a Gaussian distribution in absolute magnitude) as measured from secular and statistical parallaxes. These stars apparently belong to a young-disk population from analyses of both the solar reflex motion and their residual velocity distribution, which implies that they have an upper mass limit of around three solar masses. There is no apparent correlation of barium intensity with either luminosity or kinematic properties. The barium stars appear to be preferentially distributed in the direction of the local spiral arm, but show no preference to associate with or avoid the direction of the galactic center. They do not appear related to either the carbon or S-stars because of these tendencies and because of the stellar population to which each type of star belongs. The distribution in absolute magnitude combined with star count analyses implies that these stars are slightly less numerous than previously believed. Barium stars show infrared excesses that correlate with their barium intensities

Effect of condensed tannins in hulls of faba beans (Vivia faba L.) on the activities of trypsin (EC 2.4.21.4) and chymotrypsin (EC 2.4.21.1) in digesta collected from the small intestine of pigs

NARCIS (Netherlands)

Jansman, A.J.M.; Enting, H.; Verstegen, M.W.A.; Huisman, J.

1994-01-01

The effects of condensed tannins in hulls of faba beans (Vicia faba L.) on the activities of trypsin (EC 3.4.21.4) and chymotrypsin (EC 3.4.21.1) in digesta obtained from the small intestine of pigs were studied. Using four castrated male pigs (mean body weight 83 kg) fitted with both a simple

Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars

Science.gov (United States)

Bowler, Brendan P.; Johnson, John Asher; Marcy, Geoffrey W.; Henry, Gregory W.; Peek, Kathryn M. G.; Fischer, Debra A.; Clubb, Kelsey I.; Liu, Michael C.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

2010-01-01

We present an analysis of ~5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 lsim M */M sunlsim 2.0) with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov-Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26+9 -8%, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} M Jup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN vprop M α P β dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of α and β for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4σ level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (~50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets. Based on observations obtained at the Lick Observatory, which is operated by the University of California.

Star-forming Filament Models

International Nuclear Information System (INIS)

Myers, Philip C.

2017-01-01

New models of star-forming filamentary clouds are presented in order to quantify their properties and to predict their evolution. These 2D axisymmetric models describe filaments that have no core, one low-mass core, and one cluster-forming core. They are based on Plummer-like cylinders and spheroids that are bounded by a constant-density surface of finite extent. In contrast to 1D Plummer-like models, they have specific values of length and mass, they approximate observed column density maps, and their distributions of column density ( N -pdfs) are pole-free. Each model can estimate the star-forming potential of a core-filament system by identifying the zone of gas dense enough to form low-mass stars and by counting the number of enclosed thermal Jeans masses. This analysis suggests that the Musca central filament may be near the start of its star-forming life, with enough dense gas to make its first ∼3 protostars, while the Coronet filament is near the midpoint of its star formation, with enough dense gas to add ∼8 protostars to its ∼20 known stars. In contrast, L43 appears to be near the end of its star-forming life, since it lacks enough dense gas to add any new protostars to the two young stellar objectsalready known.

Star-forming Filament Models

Energy Technology Data Exchange (ETDEWEB)

Myers, Philip C., E-mail: pmyers@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2017-03-20

New models of star-forming filamentary clouds are presented in order to quantify their properties and to predict their evolution. These 2D axisymmetric models describe filaments that have no core, one low-mass core, and one cluster-forming core. They are based on Plummer-like cylinders and spheroids that are bounded by a constant-density surface of finite extent. In contrast to 1D Plummer-like models, they have specific values of length and mass, they approximate observed column density maps, and their distributions of column density ( N -pdfs) are pole-free. Each model can estimate the star-forming potential of a core-filament system by identifying the zone of gas dense enough to form low-mass stars and by counting the number of enclosed thermal Jeans masses. This analysis suggests that the Musca central filament may be near the start of its star-forming life, with enough dense gas to make its first ∼3 protostars, while the Coronet filament is near the midpoint of its star formation, with enough dense gas to add ∼8 protostars to its ∼20 known stars. In contrast, L43 appears to be near the end of its star-forming life, since it lacks enough dense gas to add any new protostars to the two young stellar objectsalready known.

A look at the ocean in the EC-Earth climate model

Energy Technology Data Exchange (ETDEWEB)

Sterl, Andreas; Bintanja, Richard; Severijns, Camiel [Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt (Netherlands); Brodeau, Laurent [Stockholm University, Department of Meteorology, Stockholm (Sweden); Gleeson, Emily; Semmler, Tido [Met Eireann, Dublin (Ireland); Koenigk, Torben; Wyser, Klaus [Swedish Meteorological and Hydrological Institute (SMHI), Norrkoeping (Sweden); Schmith, Torben; Yang, Shuting [Danish Meteorological Institute (DMI), Copenhagen (Denmark)

2012-12-15

EC-Earth is a newly developed global climate system model. Its core components are the Integrated Forecast System (IFS) of the European Centre for Medium Range Weather Forecasts (ECMWF) as the atmosphere component and the Nucleus for European Modelling of the Ocean (NEMO) developed by Institute Pierre Simon Laplace (IPSL) as the ocean component. Both components are used with a horizontal resolution of roughly one degree. In this paper we describe the performance of NEMO in the coupled system by comparing model output with ocean observations. We concentrate on the surface ocean and mass transports. It appears that in general the model has a cold and fresh bias, but a much too warm Southern Ocean. While sea ice concentration and extent have realistic values, the ice tends to be too thick along the Siberian coast. Transports through important straits have realistic values, but generally are at the lower end of the range of observational estimates. Exceptions are very narrow straits (Gibraltar, Bering) which are too wide due to the limited resolution. Consequently the modelled transports through them are too high. The strength of the Atlantic meridional overturning circulation is also at the lower end of observational estimates. The interannual variability of key variables and correlations between them are realistic in size and pattern. This is especially true for the variability of surface temperature in the tropical Pacific (El Nino). Overall the ocean component of EC-Earth performs well and helps making EC-Earth a reliable climate model. (orig.)

Wave Star

DEFF Research Database (Denmark)

Kramer, Morten; Andersen, Thomas Lykke

Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

X-ray sources in regions of star formation. II. The pre-main-sequence G star HDE 283572

International Nuclear Information System (INIS)

Walter, F.M.; Brown, A.; Linsky, J.L.; Rydgren, A.E.; Vrba, F.; Joint Institute for Laboratory Astrophysics, Boulder, CO; Computer Sciences Corp., El Segundo, CA; Naval Observatory, Flagstaff, AZ)

1987-01-01

This paper reports the detection of HDE 283572, a ninth-magnitude G star 8 arcmin south of RY Tau, as a bright X-ray source. The observations reveal this object to be a fairly massive (about 2 solar masses) pre-main-sequence star associated with the Taurus-Auriga star formation complex. It exhibits few of the characteristics of the classical T Tauri stars and is a good example of a naked T Tauri star. The star is a mid-G subgiant, of about three solar radii and rotates with a period of 1.5 d. The coronal and chromospheric surface fluxes are similar to those of the most active late type stars (excluding T Tauri stars). The X-ray and UV lines most likely arise in different atmospheric structures. Radiative losses are some 1000 times the quiet solar value and compare favorably with those of T Tauri stars. 49 references

Sounds of a Star

Science.gov (United States)

2001-06-01

Acoustic Oscillations in Solar-Twin "Alpha Cen A" Observed from La Silla by Swiss Team Summary Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology" . In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets (see ESO PR 07/01 ). The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun . Asteroseismology for Sun-like stars is likely to become an important probe of stellar theory in the near future. The state-of-the-art HARPS spectrograph , to be mounted on the ESO 3.6-m telescope at La Silla, will be able to search for oscillations in stars that are 100 times fainter than those for which such demanding observations are possible with CORALIE. PR Photo 23a/01 : Oscillations in a solar-like star (schematic picture). PR Photo 23b/01 : Acoustic spectrum of Alpha Centauri A , as observed with CORALIE. Asteroseismology: listening to the stars ESO PR Photo 23a/01 ESO PR Photo 23a/01 [Preview - JPEG: 357 x 400 pix - 96k] [Normal - JPEG: 713 x 800 pix - 256k] [HiRes - JPEG: 2673 x 3000 pix - 2.1Mb Caption : PR Photo 23a/01 is a graphical representation of resonating acoustic waves in the interior of a solar-like star. Red and blue

MMT HYPERVELOCITY STAR SURVEY. II. FIVE NEW UNBOUND STARS

Energy Technology Data Exchange (ETDEWEB)

Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J., E-mail: wbrown@cfa.harvard.edu, E-mail: mgeller@cfa.harvard.edu, E-mail: skenyon@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-05-20

We present the discovery of five new unbound hypervelocity stars (HVSs) in the outer Milky Way halo. Using a conservative estimate of Galactic escape velocity, our targeted spectroscopic survey has now identified 16 unbound HVSs as well as a comparable number of HVSs ejected on bound trajectories. A Galactic center origin for the HVSs is supported by their unbound velocities, the observed number of unbound stars, their stellar nature, their ejection time distribution, and their Galactic latitude and longitude distribution. Other proposed origins for the unbound HVSs, such as runaway ejections from the disk or dwarf galaxy tidal debris, cannot be reconciled with the observations. An intriguing result is the spatial anisotropy of HVSs on the sky, which possibly reflects an anisotropic potential in the central 10-100 pc region of the Galaxy. Further progress requires measurement of the spatial distribution of HVSs over the southern sky. Our survey also identifies seven B supergiants associated with known star-forming galaxies; the absence of B supergiants elsewhere in the survey implies there are no new star-forming galaxies in our survey footprint to a depth of 1-2 Mpc.

A miniature integrated multimodal sensor for measuring pH, EC and temperature for precision agriculture.

Science.gov (United States)

Futagawa, Masato; Iwasaki, Taichi; Murata, Hiroaki; Ishida, Makoto; Sawada, Kazuaki

2012-01-01

Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC) and temperature sensors. An ISFET with a Si(3)N(4) membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk.

RNA of Enterococcus faecalis Strain EC-12 Is a Major Component Inducing Interleukin-12 Production from Human Monocytic Cells.

Directory of Open Access Journals (Sweden)

Ryoichiro Nishibayashi

Full Text Available Interleukin-12 (IL-12 is an important cytokine for the immunomodulatory effects of lactic acid bacteria (LAB. Using murine immune cells, we previously reported that the RNA of Enterococcus faecalis EC-12, a LAB strain exerting probiotic-like beneficial effects, is the major IL-12-inducing immunogenic component. However, it was recently revealed that bacterial RNA can be a ligand for Toll-like receptor (TLR 13, which is only expressed in mice. Because TLR13 is not expressed in humans, the immuno-stimulatory and -modulatory effects of LAB RNA in human cells should be augmented excluding TLR13 contribution. In experiment 1 of this study, the role of LAB RNA in IL-12 induction in human immune cells was studied using three LAB strains, E.faecalis EC-12, Lactobacillus gasseri JCM5344, and Bifidobacterium breve JCM1192. RNase A treatment of heat-killed LAB significantly decreased the IL-12 production of human peripheral blood mononuclear cells on stimulation, while RNase III treatment revealed virtually no effects. Further, IL-12 production against heat-killed E. faecalis EC-12 was abolished by depleting monocytes. These results demonstrated that single stranded RNA (ssRNA of LAB is a strong inducer of IL-12 production from human monocytes. In experiment 2, major receptor for ssRNA of E. faecalis EC-12 was identified using THP-1 cells, a human monocytic cell line. The type of RNA molecules of E. faecalis EC-12 responsible for IL-12 induction was also identified. IL-12 production induced by the total RNA of E. faecalis EC-12 was significantly reduced by the treatment of siRNA for TLR8 but not for TLR7. Furthermore, both 23S and 16S rRNA, but not mRNA, of E. faecalis EC-12 markedly induced IL-12 production from THP-1 cells. These results suggested that the recognition of ssRNA of E. faecalis EC-12 was mediated by TLR8 and that rRNA was the RNA molecule that exhibited IL-12-inducing ability in human cells.

Research and development programme of the EC in the field of raw materials 1982 to 1985

International Nuclear Information System (INIS)

Anon.

1982-01-01

Brussels: The EC Cabinet Council was presented a research and development programme in the field of raw materials for the years 1982 to 1985 which covers programmes already running and new actions as an overlapping raw material research programme of the EC. The new programme is divided up into 7 subprogrammes: I) metals and minerals (formerly: primary raw materials, II) uranium, III) ceramics, IV) wood as a renewable raw material, V) recycling of wastes (house and industry, VI) regaining of non-iron metals, VII) substitution. For the continuing of running actions and for beginning new projects in the 4 years plan, a total of 17 million ECU are to be allocated in the budget of the EC which will be used in cost sharing contracts or for coordinative projects. (orig./UA) [de

THE CHANDRA VARIABLE GUIDE STAR CATALOG

International Nuclear Information System (INIS)

Nichols, Joy S.; Lauer, Jennifer L.; Morgan, Douglas L.; Sundheim, Beth A.; Henden, Arne A.; Huenemoerder, David P.; Martin, Eric

2010-01-01

Variable stars have been identified among the optical-wavelength light curves of guide stars used for pointing control of the Chandra X-ray Observatory. We present a catalog of these variable stars along with their light curves and ancillary data. Variability was detected to a lower limit of 0.02 mag amplitude in the 4000-10000 A range using the photometrically stable Aspect Camera on board the Chandra spacecraft. The Chandra Variable Guide Star Catalog (VGUIDE) contains 827 stars, of which 586 are classified as definitely variable and 241 are identified as possibly variable. Of the 586 definite variable stars, we believe 319 are new variable star identifications. Types of variables in the catalog include eclipsing binaries, pulsating stars, and rotating stars. The variability was detected during the course of normal verification of each Chandra pointing and results from analysis of over 75,000 guide star light curves from the Chandra mission. The VGUIDE catalog represents data from only about 9 years of the Chandra mission. Future releases of VGUIDE will include newly identified variable guide stars as the mission proceeds. An important advantage of the use of space data to identify and analyze variable stars is the relatively long observations that are available. The Chandra orbit allows for observations up to 2 days in length. Also, guide stars were often used multiple times for Chandra observations, so many of the stars in the VGUIDE catalog have multiple light curves available from various times in the mission. The catalog is presented as both online data associated with this paper and as a public Web interface. Light curves with data at the instrumental time resolution of about 2 s, overplotted with the data binned at 1 ks, can be viewed on the public Web interface and downloaded for further analysis. VGUIDE is a unique project using data collected during the mission that would otherwise be ignored. The stars available for use as Chandra guide stars are

Spectrophotometry of carbon stars

International Nuclear Information System (INIS)

Gow, C.E.

1975-01-01

Observations of over one hundred carbon stars have been made with the Indiana rapid spectral scanner in the red and, when possible, in the visual and blue regions of the spectrum. Five distinct subtypes of carbon stars (Barium, CH, R, N, and hydrogen deficient) are represented in the list of observed stars, although the emphasis was placed on the N stars when the observations were made. The rapid scanner was operated in the continuous sweep mode with the exit slit set at twenty angstroms, however, seeing fluctuations and guiding errors smear the spectrum to an effective resolution of approximately thirty angstroms. Nightly observations of Hayes standard stars yielded corrections for atmospheric extinction and instrumental response. The reduction scheme rests on two assumptions, that thin clouds are gray absorbers and the wavelength dependence of the sky transparency does not change during the course of the night. Several stars have been observed in the blue region of the spectrum with the Indiana SIT vidicon spectrometer at two angstroms resolution. It is possible to derive a color temperature for the yellow--red spectral region by fitting a black-body curve through two chosen continuum points. Photometric indices were calculated relative to the blackbody curve to measure the C 2 Swan band strength, the shape of the CN red (6,1) band to provide a measure of the 12 C/ 13 C isotope ratio, and in the hot carbon stars (Barium, CH, and R stars) the strength of an unidentified feature centered at 400 angstroms. An extensive abundance grid of model atmospheres was calculated using a modified version of the computer code ATLAS

Stacked Star Formation Rate Profiles of Bursty Galaxies Exhibit “Coherent” Star Formation

Science.gov (United States)

Orr, Matthew E.; Hayward, Christopher C.; Nelson, Erica J.; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Kereš, Dušan; Chan, T. K.; Schmitz, Denise M.; Miller, Tim B.

2017-11-01

In a recent work based on 3200 stacked Hα maps of galaxies at z˜ 1, Nelson et al. find evidence for “coherent star formation”: the stacked star formation rate (SFR) profiles of galaxies above (below) the “star formation main sequence” (MS) are above (below) that of galaxies on the MS at all radii. One might interpret this result as inconsistent with highly bursty star formation and evidence that galaxies evolve smoothly along the MS rather than crossing it many times. We analyze six simulated galaxies at z˜ 1 from the Feedback in Realistic Environments (FIRE) project in a manner analogous to the observations to test whether the above interpretations are correct. The trends in stacked SFR profiles are qualitatively consistent with those observed. However, SFR profiles of individual galaxies are much more complex than the stacked profiles: the former can be flat or even peak at large radii because of the highly clustered nature of star formation in the simulations. Moreover, the SFR profiles of individual galaxies above (below) the MS are not systematically above (below) those of MS galaxies at all radii. We conclude that the time-averaged coherent star formation evident stacks of observed galaxies is consistent with highly bursty, clumpy star formation of individual galaxies and is not evidence that galaxies evolve smoothly along the MS.

STAR facility tritium accountancy

International Nuclear Information System (INIS)

Pawelko, R. J.; Sharpe, J. P.; Denny, B. J.

2008-01-01

The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5 g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed. (authors)

Young Stars with SALT

Energy Technology Data Exchange (ETDEWEB)

Riedel, Adric R. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Alam, Munazza K.; Rice, Emily L.; Cruz, Kelle L. [Department of Astrophysics, The American Museum of Natural History, New York, NY 10024 (United States); Henry, Todd J., E-mail: arr@caltech.edu [RECONS Institute, Chambersburg, PA (United States)

2017-05-10

We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All of these dwarfs are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph on the South African Large Telescope, we have determined radial velocities, H-alpha, lithium 6708 Å, and potassium 7699 Å equivalent widths linked to age and activity, and spectral types for all of our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 pc of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, 9 members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find 14 young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups.

Cataclysmic Variable Stars

Science.gov (United States)

Hellier, Coel

2001-01-01

Cataclysmic variable stars are the most variable stars in the night sky, fluctuating in brightness continually on timescales from seconds to hours to weeks to years. The changes can be recorded using amateur telescopes, yet are also the subject of intensive study by professional astronomers. That study has led to an understanding of cataclysmic variables as binary stars, orbiting so closely that material transfers from one star to the other. The resulting process of accretion is one of the most important in astrophysics. This book presents the first account of cataclysmic variables at an introductory level. Assuming no previous knowledge of the field, it explains the basic principles underlying the variability, while providing an extensive compilation of cataclysmic variable light curves. Aimed at amateur astronomers, undergraduates, and researchers, the main text is accessible to those with no mathematical background, while supplementary boxes present technical details and equations.

Post-giant evolution of helium stars

International Nuclear Information System (INIS)

Schoenberner, D.

1977-01-01

Extremely hydrogen deficient stars (helium stars and R Coronae Borealis variables) are considered to be remnants of double shell source stars (of the asymptotic giant branch). The evolution of stars with a condensed C/O-core and a helium envelope is followed numerically from the red giant stage to the white dwarf domain, crossing the regions of R CrB- and helium stars (so far analyzed). They have typically masses M/M(sun) = 0.7 and luminosities log L/L(sun) = 4.1. The time for crossing the helium star domain is some 10 3 years. The corresponding times in the R CrB-region amounts up to several 10 4 years. The lower limit of the death rate of helium stars is estimated to be 4 x 10 -14 pc -3 yr -1 . This value is only a factor of ten lower than the birth rate of all non-DA white dwarfs. It is therefore possible that the helium stars are the precursors of helium rich white dwarfs. As a consequence, a significant fraction of all stars which end their lives as white dwarfs should pass through the helium star phase. (orig.) [de

Covering tree with stars

DEFF Research Database (Denmark)

Baumbach, Jan; Guo, Jiong; Ibragimov, Rashid

2015-01-01

We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

Energy star compliant voice over internet protocol (VoIP) telecommunications network including energy star compliant VoIP devices

Science.gov (United States)

Kouchri, Farrokh Mohammadzadeh

2012-11-06

A Voice over Internet Protocol (VoIP) communications system, a method of managing a communications network in such a system and a program product therefore. The system/network includes an ENERGY STAR (E-star) aware softswitch and E-star compliant communications devices at system endpoints. The E-star aware softswitch allows E-star compliant communications devices to enter and remain in power saving mode. The E-star aware softswitch spools messages and forwards only selected messages (e.g., calls) to the devices in power saving mode. When the E-star compliant communications devices exit power saving mode, the E-star aware softswitch forwards spooled messages.

AGB [asymptotic giant branch]: Star evolution

International Nuclear Information System (INIS)

Becker, S.A.

1987-01-01

Asymptotic giant branch stars are red supergiant stars of low-to-intermediate mass. This class of stars is of particular interest because many of these stars can have nuclear processed material brought up repeatedly from the deep interior to the surface where it can be observed. A review of recent theoretical and observational work on stars undergoing the asymptotic giant branch phase is presented. 41 refs

Star-Branched Polymers (Star Polymers)

KAUST Repository

Hirao, Akira; Hayashi, Mayumi; Ito, Shotaro; Goseki, Raita; Higashihara, Tomoya; Hadjichristidis, Nikolaos

2015-01-01

The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic

The Diversity of Neutron Stars

Science.gov (United States)

Kaplan, David L.

2004-12-01

Neutron stars are invaluable tools for exploring stellar death, the physics of ultra-dense matter, and the effects of extremely strong magnetic fields. The observed population of neutron stars is dominated by the >1000 radio pulsars, but there are distinct sub-populations that, while fewer in number, can have significant impact on our understanding of the issues mentioned above. These populations are the nearby, isolated neutron stars discovered by ROSAT, and the central compact objects in supernova remnants. The studies of both of these populations have been greatly accelerated in recent years through observations with the Chandra X-ray Observatory and the XMM-Newton telescope. First, we discuss radio, optical, and X-ray observations of the nearby neutron stars aimed at determining their relation to the Galactic neutron star population and at unraveling their complex physical processes by determining the basic astronomical parameters that define the population---distances, ages, and magnetic fields---the uncertainties in which limit any attempt to derive basic physical parameters for these objects. We conclude that these sources are 1e6 year-old cooling neutron stars with magnetic fields above 1e13 Gauss. Second, we describe the hollow supernova remnant problem: why many of the supernova remnants in the Galaxy have no indication of central neutron stars. We have undertaken an X-ray census of neutron stars in a volume-limited sample of Galactic supernova remnants, and from it conclude that either many supernovae do not produce neutron stars contrary to expectation, or that neutron stars can have a wide range in cooling behavior that makes many sources disappear from the X-ray sky.

RADIAL STABILITY IN STRATIFIED STARS

International Nuclear Information System (INIS)

Pereira, Jonas P.; Rueda, Jorge A.

2015-01-01

We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting any two phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case

From clouds to stars

International Nuclear Information System (INIS)

Elmegreen, B.G.

1982-01-01

At the present time, the theory of star formation must be limited to what we know about the lowest density gas, or about the pre-main sequence stars themselves. We would like to understand two basic processes: 1) how star-forming clouds are created from the ambient interstellar gas in the first place, and 2) how small parts of these clouds condense to form individual stars. We are interested also in knowing what pre-main sequence stars are like, and how they can interact with their environment. These topics are reviewed in what follows. In this series of lectures, what we know about the formation of stars is tentatively described. The lectures begin with a description of the interstellar medium, and then they proceed along the same direction that a young star would follow during its creation, namely from clouds through the collapse phase and onto the proto-stellar phase. The evolution of viscous disks and two models for the formation of the solar system are described in the last lectures. The longest lectures, and the topics that are covered in most detail, are not necessarily the ones for which we have the most information. Physically intuitive explanations for the various processes are emphasized, rather then mathematical explanations. In some cases, the mathematical aspects are developed as well, but only when the equations can be used to give important numerical values for comparison with the observations

Quark phases in neutron stars and a third family of compact stars as signature for phase transitions

International Nuclear Information System (INIS)

Schertler, K.; Greiner, C.; Schaffner-Bielich, J.; Thoma, M.H.

2000-01-01

The appearance of quark phases in the dense interior of neutron stars provides one possibility to soften the equation of state (EOS) of neutron star matter at high densities. This softening leads to more compact equilibrium configurations of neutron stars compared to pure hadronic stars of the same mass. We investigate the question to which amount the compactness of a neutron star can be attributed to the presence of a quark phase. For this purpose we employ several hadronic EOS in the framework of the relativistic mean-field (RMF) model and an extended MIT bag model to describe the quark phase. We find that -- almost independent of the model parameters -- the radius of a pure hadronic neutron star gets typically reduced by 20-30% if a pure quark phase in the center of the star does exist. For some EOS we furthermore find the possibility of a third family of compact stars which may exist besides the two known families of white dwarfs and neutron stars. We show how an experimental proof of the existence of a third family by mass and radius measurements may provide a unique signature for a phase transition inside neutron stars

Star Formation Activity Beyond the Outer Arm. I. WISE -selected Candidate Star-forming Regions

Energy Technology Data Exchange (ETDEWEB)

Izumi, Natsuko; Yasui, Chikako; Saito, Masao [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan); Kobayashi, Naoto; Hamano, Satoshi, E-mail: natsuko.izumi@nao.ac.jp [Laboratory of Infrared High-resolution spectroscopy (LIH), Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan)

2017-10-01

The outer Galaxy beyond the Outer Arm provides a good opportunity to study star formation in an environment significantly different from that in the solar neighborhood. However, star-forming regions in the outer Galaxy have never been comprehensively studied or cataloged because of the difficulties in detecting them at such large distances. We studied 33 known young star-forming regions associated with 13 molecular clouds at R {sub G} ≥ 13.5 kpc in the outer Galaxy with data from the Wide-field Infrared Survey Explorer ( WISE ) mid-infrared all-sky survey. From their color distribution, we developed a simple identification criterion of star-forming regions in the outer Galaxy with the WISE color. We applied the criterion to all the WISE sources in the molecular clouds in the outer Galaxy at R {sub G} ≥ 13.5 kpc detected with the Five College Radio Astronomy Observatory (FCRAO) {sup 12}CO survey of the outer Galaxy, of which the survey region is 102.°49 ≤  l  ≤ 141.°54, −3.°03 ≤  b  ≤ 5.°41, and successfully identified 711 new candidate star-forming regions in 240 molecular clouds. The large number of samples enables us to perform the statistical study of star formation properties in the outer Galaxy for the first time. This study is crucial to investigate the fundamental star formation properties, including star formation rate, star formation efficiency, and initial mass function, in a primordial environment such as the early phase of the Galaxy formation.

Fallen star legends and traditional religion of Japan: an aspect of star lore

Science.gov (United States)

Goto, Akira

2015-08-01

Japanese star lore is a complex mixture of animism, Buddhism, Shinto-ism, Confucianism and folk beliefs. Although some studies have been done on rituals concerning constellation developed in esoteric Buddhism (e.g. Journal Culture and Cosmos, Vol. 10 no 1 and 2), studies on other aspects of Japanese star lore are limited, in particular, to the English audience.In historic literatures, there often mentioned abnormal astronomical phenomena, such as, eclipse, meteors and comets. In this paper, I will discuss the possibility of reference to these astronomical phenomena in order to talk about some historical facts.In western part of Japan, there are Shinto shrines and Buddhistic temples that are said to be built as monuments of fallen stars. Usually fallen stars were divided into three, and a trio of shrines/temples are said to be the remnants of this phenomenon. Similar legends are found in Kudamatsu (that means "fallen pine=pine where stars fallen") of Yamaguchi Prefecture, Bisei-cho (that means "beautiful star") of Okayama Prefecture, Hoshida (that means "rice field or village of star") shrine of Osaka, and also Hoshida shrine of Nagoya.The purpose of this presentation is not to argue whether fallen star legend was truly astronomical phenomenon, such as, meteor or not. Instead, I will discuss why similar legends have been talked concerning the origin of particular shrines or temples. Citing Eliade who related gorge and alchemy producing spark to astronomical phenomena, I will disclose the possibility to relate these astronomical legends to the coming of the naturalized Japanese from Korean Peninsula who introducd forge to Japan abound 5 to 6 centuries.

Wolf-Rayet stars and galactic structure

International Nuclear Information System (INIS)

Stenholm, B.

1975-01-01

A 15 0 wide strip along the galactic equator between longitudes 250 0 and 360 0 has been searched for Wolf-Rayet stars. Six new WR stars and four new planetary nebulae have been found. Seven stars earlier listed as WR stars have been rejected as such. The new WR stars in the 'Luminous Stars in the Southern Milky Way' are discussed. A sample of 154 WR stars has been treated statistically. For the distribution in longitude, comparisons are made with OB stars and classical cepheids. The differences in distribution are thought to be an age effect. An effort to explain the empty interval towards the anticentre is made. The distribution in latitude is compared with young clusters and long-period cepheids. The physical plane formed by these objects is tilted about one degree to the galactic plane and the tilt is upwards in the Cygnus direction. This result is also received by a least squares solution of the objects when given in rectangular coordinates. The WR star sample is regarded as fairly complete up to a distance of 5 kpc. (orig.) [de

Life and death of the stars

CERN Document Server

Srinivasan, Ganesan

2014-01-01

This volume is devoted to one of the fascinating things about stars: how they evolve as they age. This evolution is different for stars of different masses. How stars end their lives when their supply of energy is exhausted also depends on their masses. Interestingly, astronomers conjectured about the ultimate fate of the stars even before the details of their evolution became clear. Part I of this book gives an account of the remarkable predictions made during the 1920s and 1930s concerning the ultimate fate of stars. Since much of this development hinged on quantum physics that emerged during this time, a detailed introduction to the relevant physics is included in the book. Part II is a summary of the life history of stars. This discussion is divided into three parts: low-mass stars, like our Sun, intermediate-mass stars, and massive stars. Many of the concepts of contemporary astrophysics were built on the foundation erected by Subrahmanyan Chandrasekhar in the 1930s. This book, written during his birth c...

The planned EC Directive on 'Integrated Pollution Prevention and Control' (IPC)

International Nuclear Information System (INIS)

Sellner, D.; Schnutenhaus, J.

1993-01-01

This EC Directive is intended to incorporate integrated pollution control as a mandatory obligation in the legal provisions governing industrial installations licensing within the EC. The article in hand presents an assessment of the Directive and discusses some possible impacts on the German national law in the field of pollution control, which hitherto has been defined on the basis of a preferably medium-oriented approach. A serious point of deviation from the German approach is seen in the fact that the draft's provisions relating to the licensing of industrial installations defines certain pre-conditions allowing a plant in a low-polluted area to be licensed, although the pollution control systems of the plant do not them come up to the state-of-the-art in pollution abatement technology. This is seen as a fact jeopardizing the principle of precantionary measures which has been firmly established in German pollution control law. (orig./HP) [de

STAR FORMATION IN THE TAURUS FILAMENT L 1495: FROM DENSE CORES TO STARS

International Nuclear Information System (INIS)

Schmalzl, Markus; Kainulainen, Jouni; Henning, Thomas; Launhardt, Ralf; Quanz, Sascha P.; Alves, Joao; Goodman, Alyssa A.; Pineda, Jaime E.; Roman-Zuniga, Carlos G.

2010-01-01

We present a study of dense structures in the L 1495 filament in the Taurus Molecular Cloud and examine its star-forming properties. In particular, we construct a dust extinction map of the filament using deep near-infrared observations, exposing its small-scale structure in unprecedented detail. The filament shows highly fragmented substructures and a high mass-per-length value of M line = 17 M sun pc -1 , reflecting star-forming potential in all parts of it. However, a part of the filament, namely B 211, is remarkably devoid of young stellar objects. We argue that in this region the initial filament collapse and fragmentation is still taking place and star formation is yet to occur. In the star-forming part of the filament, we identify 39 cores with masses from 0.4 to 10 M sun and preferred separations in agreement with the local Jeans length. Most of these cores exceed the Bonnor-Ebert critical mass, and are therefore likely to collapse and form stars. The dense core mass function follows a power law with exponent Γ = 1.2 ± 0.2, a form commonly observed in star-forming regions.

PHOTOMETRIC VARIABILITY IN KEPLER TARGET STARS: THE SUN AMONG STARS-A FIRST LOOK

International Nuclear Information System (INIS)

Basri, Gibor; Walkowicz, Lucianne M.; Batalha, Natalie; Jenkins, Jon; Borucki, William J.; Koch, David; Caldwell, Doug; Gilliland, Ronald L.; Dupree, Andrea K.; Latham, David W.; Meibom, Soeren; Howell, Steve; Brown, Tim

2010-01-01

The Kepler mission provides an exciting opportunity to study the light curves of stars with unprecedented precision and continuity of coverage. This is the first look at a large sample of stars with photometric data of a quality that has heretofore been only available for our Sun. It provides the first opportunity to compare the irradiance variations of our Sun to a large cohort of stars ranging from very similar to rather different stellar properties, at a wide variety of ages. Although Kepler data are in an early phase of maturity, and we only analyze the first month of coverage, it is sufficient to garner the first meaningful measurements of our Sun's variability in the context of a large cohort of main-sequence stars in the solar neighborhood. We find that nearly half of the full sample is more active than the active Sun, although most of them are not more than twice as active. The active fraction is closer to a third for the stars most similar to the Sun, and rises to well more than half for stars cooler than mid-K spectral types.

The origin of Wolf-Rayet stars

International Nuclear Information System (INIS)

Doom, C.

1987-01-01

The paper reviews the origin of Wolf-Rayet (WR) stars, with emphasis on the so-called Population I WR stars which are associated with the young and luminous stellar population. A description is given of the observational characteristics i.e. classification, luminosities composition, etc. of WR stars. The origin and evolution of WR stars is described, including the single, binary, subtypes and ratio WR/O. The interaction of the WR stars with their environment is discussed with respect to the energy deposition and composition anomalies. A brief account of the discovery of WR stars in other galaxies is given. Finally, some of the main issues in the research into the structure and evolution of WR stars are outlined. (U.K.)

Neutron Stars and Pulsars

CERN Document Server

Becker, Werner

2009-01-01

Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

Connecting the Cosmic Star Formation Rate with the Local Star Formation

Science.gov (United States)

Gribel, Carolina; Miranda, Oswaldo D.; Williams Vilas-Boas, José

2017-11-01

We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR mapping through the density probability distribution functions commonly used to study the role of turbulence in the star-forming regions of the Galaxy. We obtain a consistent mapping from redshift z˜ 20 up to the present (z = 0). Our results show that the turbulence exhibits a dual character, providing high values for the star formation efficiency ( ˜ 0.32) in the redshift interval z˜ 3.5{--}20 and reducing its value to =0.021 at z = 0. The value of the Mach number ({{ M }}{crit}), from which rapidly decreases, is dependent on both the polytropic index (Γ) and the minimum density contrast of the gas. We also derive Larson’s first law associated with the velocity dispersion ( ) in the local star formation regions. Our model shows good agreement with Larson’s law in the ˜ 10{--}50 {pc} range, providing typical temperatures {T}0˜ 10{--}80 {{K}} for the gas associated with star formation. As a consequence, dark matter halos of great mass could contain a number of halos of much smaller mass, and be able to form structures similar to globular clusters. Thus, Larson’s law emerges as a result of the very formation of large-scale structures, which in turn would allow the formation of galactic systems, including our Galaxy.

VARIABILITY AND STAR FORMATION IN LEO T, THE LOWEST LUMINOSITY STAR-FORMING GALAXY KNOWN TODAY

Energy Technology Data Exchange (ETDEWEB)

Clementini, Gisella; Cignoni, Michele; Ramos, Rodrigo Contreras; Federici, Luciana; Tosi, Monica [INAF, Osservatorio Astronomico di Bologna, I-40127 Bologna (Italy); Ripepi, Vincenzo; Marconi, Marcella; Musella, Ilaria, E-mail: gisella.clementini@oabo.inaf.it, E-mail: rodrigo.contreras@oabo.inaf.it, E-mail: luciana.federici@oabo.inaf.it, E-mail: monica.tosi@oabo.inaf.it, E-mail: michele.cignoni@unibo.it, E-mail: ripepi@na.astro.it, E-mail: marcella@na.astro.it, E-mail: ilaria@na.astro.it [INAF, Osservatorio Astronomico di Capodimonte, I-80131 Napoli (Italy)

2012-09-10

We present results from the first combined study of variable stars and star formation history (SFH) of the Milky Way 'ultra-faint' dwarf (UFD) galaxy Leo T, based on F606W and F814W multi-epoch archive observations obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. We have detected 14 variable stars in the galaxy. They include one fundamental-mode RR Lyrae star and 11 Anomalous Cepheids with periods shorter than 1 day, thus suggesting the occurrence of multiple star formation episodes in this UFD, of which one about 10 Gyr ago produced the RR Lyrae star. A new estimate of the distance to Leo T of 409{sup +29}{sub -27} kpc (distance modulus of 23.06 {+-} 0.15 mag) was derived from the galaxy's RR Lyrae star. Our V, V - I color-magnitude diagram (CMD) of Leo T reaches V {approx} 29 mag and shows features typical of a galaxy in transition between dwarf irregular and dwarf spheroidal types. A quantitative analysis of the SFH, based on the comparison of the observed V, V - I CMD with the expected distribution of stars for different evolutionary scenarios, confirms that Leo T has a complex SFH dominated by two enhanced periods about 1.5 and 9 Gyr ago, respectively. The distribution of stars and gas shows that the galaxy has a fairly asymmetric structure.

Dark stars

DEFF Research Database (Denmark)

Maselli, Andrea; Pnigouras, Pantelis; Nielsen, Niklas Grønlund

2017-01-01

to the formation of compact objects predominantly made of dark matter. Considering both fermionic and bosonic (scalar φ4) equations of state, we construct the equilibrium structure of rotating dark stars, focusing on their bulk properties and comparing them with baryonic neutron stars. We also show that these dark......Theoretical models of self-interacting dark matter represent a promising answer to a series of open problems within the so-called collisionless cold dark matter paradigm. In case of asymmetric dark matter, self-interactions might facilitate gravitational collapse and potentially lead...... objects admit the I-Love-Q universal relations, which link their moments of inertia, tidal deformabilities, and quadrupole moments. Finally, we prove that stars built with a dark matter equation of state are not compact enough to mimic black holes in general relativity, thus making them distinguishable...

SX Phoenicis stars

International Nuclear Information System (INIS)

Nemec, J.; Mateo, M.

1990-01-01

The purpose of this paper is to review the basic observational information concerning SX Phe stars, including recent findings such as the discovery of about 40 low-luminosity variable stars in the Carina dwarf galaxy and identification of at least one SX Phe star in the metal-rich globular cluster M71. Direct evidence supporting the hypothesis that at least some BSs are binary systems comes from the discovery of two contact binaries and a semidetached binary among the 50 BSs in the globular cluster NGC 5466. Since these systems will coalesce on a time scale 500 Myr, it stands to reason that many (if not most) BSs are coalesced binaries. The merger hypothesis also explains the relatively-large masses (1.0-1.2 solar masses) that have been derived for SX Phe stars and halo BSs, and may also account for the nonvariable BSs in the 'SX Phe instability strip'. 132 refs

Inactivation of the Ecs ABC Transporter of Staphylococcus aureus Attenuates Virulence by Altering Composition and Function of Bacterial Wall

NARCIS (Netherlands)

Jonsson, Ing-Marie; Juuti, Jarmo T.; Francois, Patrice; AlMajidi, Rana; Pietiainen, Milla; Girard, Myriam; Lindholm, Catharina; Saller, Manfred J.; Driessen, Arnold J. M.; Kuusela, Pentti; Bokarewa, Maria; Schrenzel, Jacques; Kontinen, Vesa P.

2010-01-01

Background: Ecs is an ATP-binding cassette (ABC) transporter present in aerobic and facultative anaerobic Gram-positive Firmicutes. Inactivation of Bacillus subtilis Ecs causes pleiotropic changes in the bacterial phenotype including inhibition of intramembrane proteolysis. The molecule(s)

Distances of Dwarf Carbon Stars

Science.gov (United States)

Harris, Hugh C.; Dahn, Conard C.; Subasavage, John P.; Munn, Jeffrey A.; Canzian, Blaise J.; Levine, Stephen E.; Monet, Alice B.; Pier, Jeffrey R.; Stone, Ronald C.; Tilleman, Trudy M.; Hartkopf, William I.

2018-06-01

Parallaxes are presented for a sample of 20 nearby dwarf carbon stars. The inferred luminosities cover almost two orders of magnitude. Their absolute magnitudes and tangential velocities confirm prior expectations that some originate in the Galactic disk, although more than half of this sample are halo stars. Three stars are found to be astrometric binaries, and orbital elements are determined; their semimajor axes are 1–3 au, consistent with the size of an AGB mass-transfer donor star.

Completion Report for Well ER-EC-1

International Nuclear Information System (INIS)

Townsend, M.J.

2000-01-01

Well ER-EC-1 was drilled for the U.S. Department of Energy, Nevada Operations Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in the spring of 1999 as part of the U.S. Department of Energy's hydrogeologic investigation well program in the Western Pahute Mesa - Oasis Valley region just west of the Test Site. A 44.5-centimeter surface hole was drilled and cased off to the depth 675.1 meters below the surface. The hole diameter was then decreased to 31.1 centimeters for drilling to a total depth of 1,524.0 meters. A preliminary composite, static, water level was measured at the depth of approximately 566.3 meters prior to installation of the completion string. One completion string with three isolated, slotted intervals was installed in the well. Detailed lithologic descriptions with preliminary stratigraphic assignments are included in the report. These are based on composite drill cuttings collected every 3 meters and 31 sidewall samples taken at various depths below 680 meters, supplemented by geophysical log data. Detailed chemical and mineralogical studies of rock samples are in progress. The well penetrated Tertiary-age lava and tuff of the Timber Mountain Group, the Paintbrush Group, the Calico Hills Formation, the Crater Flat Group, and the Volcanics of Quartz Mountain. The preliminary geologic interpretation of data from Well ER-EC-1 indicates the presence of a structural trough or bench filled with a thick section of post-Rainier Mesa lava. These data also suggest that this site is located on a buried structural ridge that may separate the Silent Canyon and Timber Mountain caldera complexes

Ferro-based derivatizing agents for LC/MS an LC/EC/MS

NARCIS (Netherlands)

Seiwert, Bettina

2007-01-01

Within this thesis, the development and application of ferrocene-based derivatizing agents for LC/MS and LC/EC/MS is presented. The advantages of derivatization by ferrocenes are the similtaneous introduction of a mass tag and an electroactive group, which make them ideally suited for LC/MS and

Discovery of a New Nearby Star

Science.gov (United States)

Teegarden, B. J.; Pravdo, S. H.; Covey, K.; Frazier, O.; Hawley, S. L.; Hicks, M.; Lawrence, K.; McGlynn, T.; Reid, I. N.; Shaklan, S. B.

2003-01-01

We report the discovery of a nearby star with a very large proper motion of 5.06 +/- 0.03 arcsec/yr. The star is called SO025300.5+165258 and referred to herein as HPMS (high proper motion star). The discovery came as a result of a search of the SkyMorph database, a sensitive and persistent survey that is well suited for finding stars with high proper motions. There are currently only 7 known stars with proper motions greater than 5 arcsec/yr. We have determined a preliminary value for the parallax of pi = 0.43 +/- 0.13 arcsec. If this value holds our new star ranks behind only the Alpha Centauri system (including Proxima Centauri) and Barnard's star in the list of our nearest stellar neighbours. The spectrum and measured tangential velocity indicate that HPMS is a main-sequence star with spectral type M6.5. However, if our distance measurement is correct, the HPMS is underluminous by 1.2 +/- 0.7 mag.

Star trackers for attitude determination

DEFF Research Database (Denmark)

Liebe, Carl Christian

1995-01-01

One problem comes to all spacecrafts using vector information. That is the problem of determining the attitude. This paper describes how the area of attitude determination instruments has evolved from simple pointing devices into the latest technology, which determines the attitude by utilizing...... a CCD camera and a powerful microcomputer. The instruments are called star trackers and they are capable of determining the attitude with an accuracy better than 1 arcsecond. The concept of the star tracker is explained. The obtainable accuracy is calculated, the numbers of stars to be included...... in the star catalogue are discussed and the acquisition of the initial attitude is explained. Finally the commercial market for star trackers is discussed...

THE CLASSIFICATION OF KEPLER B-STAR VARIABLES

International Nuclear Information System (INIS)

McNamara, Bernard J.; Jackiewicz, Jason; McKeever, Jean

2012-01-01

The light curves of 252 B-star candidates in the Kepler database are analyzed in a similar fashion to that done by Balona et al. to further characterize B-star variability, increase the sample of variable B stars for future study, and to identify stars whose power spectra include particularly interesting features such as frequency groupings. Stars are classified as either constant light emitters, β Cep stars, slowly pulsating B stars (SPBs), hybrid pulsators, binaries or stars whose light curves are dominated by rotation (Bin/Rot), hot subdwarfs, or white dwarfs. One-hundred stars in our sample were found to be either light constants or to be variable at a level of less than 0.02 mmag. We increase the number of candidate B-star variables found in the Kepler database by Balona et al. in the following fashion: β Cep stars from 0 to 10, SPBs from eight to 54, hybrid pulsators from seven to 21, and Bin/Rot stars from 23 to 82. For comparison purposes, approximately 51 SPBs and six hybrids had been known prior to 2007. The number of β Cep stars known prior to 2004 was 93. A secondary result of this study is the identification of an additional 11 pulsating white dwarf candidates, four of which possess frequency groupings.

Stars get dizzy after lunch

International Nuclear Information System (INIS)

Zhang, Michael; Penev, Kaloyan

2014-01-01

Exoplanet searches have discovered a large number of h ot Jupiters — high-mass planets orbiting very close to their parent stars in nearly circular orbits. A number of these planets are sufficiently massive and close-in to be significantly affected by tidal dissipation in the parent star, to a degree parameterized by the tidal quality factor Q * . This process speeds up their star's rotation rate while reducing the planet's semimajor axis. In this paper, we investigate the tidal destruction of hot Jupiters. Because the orbital angular momenta of these planets are a significant fraction of their star's rotational angular momenta, they spin up their stars significantly while spiraling to their deaths. Using the Monte Carlo simulation, we predict that for Q * = 10 6 , 3.9 × 10 –6 of stars with the Kepler Target Catalog's mass distribution should have a rotation period shorter than 1/3 day (8 hr) due to accreting a planet. Exoplanet surveys such as SuperWASP, HATnet, HATsouth, and KELT have already produced light curves of millions of stars. These two facts suggest that it may be possible to search for tidally destroyed planets by looking for stars with extremely short rotational periods, then looking for remnant planet cores around those candidates, anomalies in the metal distribution, or other signatures of the recent accretion of the planet.

Insights from simulations of star formation

International Nuclear Information System (INIS)

Larson, Richard B

2007-01-01

Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circumstellar discs often form from the gas being accreted by the forming stars, and accretion from these discs may be episodic, driven by gravitational instabilities or by protostellar interactions. Star-forming clouds typically develop filamentary structures, which may, along with the thermal physics, play an important role in the origin of stellar masses because of the sensitivity of filament fragmentation to temperature variations. Simulations of the formation of star clusters show that the most massive stars form by continuing accretion in the dense cluster cores, and this again is a runaway process that couples star formation and cluster formation. Star-forming clouds also tend to develop hierarchical structures, and smaller groups of forming objects tend to merge into progressively larger ones, a generic feature of self-gravitating systems that is common to star formation and galaxy formation. Because of the large range of scales and the complex dynamics involved, analytic models cannot adequately describe many aspects of star formation, and detailed numerical simulations are needed to advance our understanding of the subject. 'The purpose of computing is insight, not numbers.' Richard W Hamming, in Numerical Methods for Scientists and Engineers (1962) 'There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.' William Shakespeare, in Hamlet, Prince of Denmark (1604) (key issues review)

Insights from simulations of star formation

Energy Technology Data Exchange (ETDEWEB)

Larson, Richard B [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States)

2007-03-15

Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circumstellar discs often form from the gas being accreted by the forming stars, and accretion from these discs may be episodic, driven by gravitational instabilities or by protostellar interactions. Star-forming clouds typically develop filamentary structures, which may, along with the thermal physics, play an important role in the origin of stellar masses because of the sensitivity of filament fragmentation to temperature variations. Simulations of the formation of star clusters show that the most massive stars form by continuing accretion in the dense cluster cores, and this again is a runaway process that couples star formation and cluster formation. Star-forming clouds also tend to develop hierarchical structures, and smaller groups of forming objects tend to merge into progressively larger ones, a generic feature of self-gravitating systems that is common to star formation and galaxy formation. Because of the large range of scales and the complex dynamics involved, analytic models cannot adequately describe many aspects of star formation, and detailed numerical simulations are needed to advance our understanding of the subject. 'The purpose of computing is insight, not numbers.' Richard W Hamming, in Numerical Methods for Scientists and Engineers (1962) 'There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.' William Shakespeare, in Hamlet, Prince of Denmark (1604) (key issues review)

RR Lyrae stars in and around NGC 6441: signatures of dissolving cluster stars

Science.gov (United States)

Kunder, Andrea

2018-06-01

Detailed elemental abundance patterns of metal-poor ([Fe/H]~ -1 dex) stars in the Galactic bulge indicate that a number of them are consistent with globular cluster (GC) stars and may be former members of dissolved GCs. This would indicate that a few per cent of the Galactic bulge was built up from destruction and/or evaporation of globular clusters. Here an attempt is made to identify such presumptive destroyed stars originating from the massive, inner Galaxy globular cluster NGC~6441 using its rich RR Lyrae variable star (RRL) population. We present radial velocities of forty RRLs centered on the globular cluster NGC~6441. All of the 13 RRLs observed within the cluster tidal radius have velocities consistent with cluster membership, with an average radial velocity of 24 +- 5~km/s and a star-to-star scatter of 11~km/s. This includes two new RRLs that were previously not associated with the cluster. Eight RRLs with radial velocities consistent with cluster membership but up to three time the distance from the tidal radius are also reported. These potential extra-tidal RRLs also have exceptionally long periods, which is a curious characteristic of the NGC~6441 RRL population that hosts RRLs with periods longer than seen anywhere else in the Milky Way. As expected of stripped cluster stars, most are inline with the cluster's orbit. Therefore, either the tidal radius of NGC~6441 is underestimated and/or we are seeing dissolving cluster stars stemming from NGC~6441 that are building up the old spheroidal bulge. Both the mean velocity of the cluster as well as the underlying field population is consistent with belonging to an old spheroidal bulge with low rotation and high velocity dispersion that formed before the bar.

Evolution of massive close binary stars

International Nuclear Information System (INIS)

Masevich, A.G.; Tutukov, A.V.

1982-01-01

Some problems of the evolution of massive close binary stars are discussed. Most of them are nonevolutionized stars with close masses of components. After filling the Roche cavity and exchange of matter between the components the Wolf-Rayet star is formed. As a result of the supernovae explosion a neutron star or a black hole is formed in the system. The system does not disintegrate but obtains high space velocity owing to the loss of the supernovae envelope. The satellite of the neutron star or black hole - the star of the O or B spectral class loses about 10 -6 of the solar mass for a year. Around the neighbouring component a disc of this matter is formed the incidence of which on a compact star leads to X radiation appearance. The neutron star cannot absorb the whole matter of the widening component and the binary system submerges into the common envelope. As a result of the evolution of massive close binary systems single neutron stars can appear which after the lapse of some time become radiopulsars. Radiopulsars with such high space velocities have been found in our Galaxy [ru

Wolf-Rayet Stars in Starburst Galaxies

OpenAIRE

Mas-Hesse, J. Miguel; Kunth, Daniel; Cervino, Miguel

1999-01-01

Wolf-Rayet stars have been detected in a large number of galaxies experiencing intense bursts of star formation. All stars initially more massive than a certain, metallicity-dependent, value are believed to experience the Wolf-Rayet phase at the end of their evolution, just before collapsing in supernova explosion. The detection of Wolf-Rayet stars puts therefore important constraints on the evolutionary status of starbursts, the properties of their Initial Mass Functions and their star forma...

Carbon stars in lmc clusters revisited

OpenAIRE

Marigo, Paola; Girardi, Leo Alberto; Chiosi, Cesare

1996-01-01

Examining the available data for AGB stars in the Large Magellanic Cloud (LMC) clusters, we address the question about the mass interval of low- and intermediate-mass stars which eventually evolve into carbon stars (C stars) during the TP-AGB phase. We combine the data compiled by Frogel, Mould & Blanco (1990) - near infrared photometry and spectral classification for luminous AGB stars in clusters - with the ages for individual clusters derived from independent methods. The resulting distrib...

Comparing the asteroseismic properties of pulsating extremely low-mass pre-white dwarf stars and δ Scuti stars

Directory of Open Access Journals (Sweden)

Arias J.P.Sánchez

2017-01-01

Full Text Available We present the first results of a detailed comparison between the pulsation properties of pulsating Extremely Low-Mass pre-white dwarf stars (the pre-ELMV variable stars and δ Scuti stars. The instability domains of these very different kinds of stars nearly overlap in the log Teff vs. log g diagram, leading to a degeneracy in the classification of the stars. Our aim is to provide asteroseismic tools for their correct classification.

A Miniature Integrated Multimodal Sensor for Measuring pH, EC and Temperature for Precision Agriculture

Directory of Open Access Journals (Sweden)

Hiroaki Murata

2012-06-01

Full Text Available Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC and temperature sensors. An ISFET with a Si₃N₄ membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk.

CCD Photometry Using Multiple Comparison Stars

Directory of Open Access Journals (Sweden)

Yonggi Kim

2004-09-01

Full Text Available The accuracy of CCD observations obtained at the Korean 1.8 m telescope has been studied. Seventeen comparison stars in the vicinity of the cataclysmic variable BG CMi have been measured. The ``artificial" star has been used instead of the ``control" star, what made possible to increase accuracy estimates by a factor of 1.3-2.1 times for ``good" and ``cloudy" nights, respectively. The algorithm of iterative determination of accuracy and weights of few comparison stars contributing to the artificial star, has been presented. The accuracy estimates for 13-mag stars are around 0.002 m mag for exposure times of 30 sec.

Hyperon-mixed neutron stars

International Nuclear Information System (INIS)

Takatsuka, Tatsuyuki

2004-01-01

Hyperon mixing in neutron star matter is investigated by the G-matrix-based effective interaction approach under the attention to use the YN and the YY potentials compatible with hypernuclear data and is shown to occur at densities relevant to neutron star cores, together with discussions to clarify the mechanism of hyperon contamination. It is remarked that developed Y-mixed phase causes a dramatic softening of the neutron star equation of state and leads to the serious problem that the resulting maximum mass M max for neutron star model contradicts the observed neutron star mass (M max obs = 1.44 M Θ ), suggesting the necessity of some extra repulsion'' in hypernuclear system. It is shown that the introduction of three-body repulsion similar to that in nuclear system can resolve the serious situation and under the consistency with observation (M max > M obs ) the threshold densities for Λ and Σ - are pushed to higher density side, from 2ρ 0 to ∼ 4ρ 0 (ρ 0 being the nuclear density). On the basis of a realistic Y-mixed neutron star model, occurrence of Y-superfluidity essential for ''hyperon cooling'' scenario is studied and both of Λ- and Σ - -superfluids are shown to be realized with their critical temperatures 10 8-9 K, meaning that the hyperon cooling'' is a promising candidate for a fast non-standard cooling demanded for some neutron stars with low surface temperature. A comment is given as to the consequence of less attractive ΛΛ interaction suggested by the ''NAGARA event'' ΛΛ 6 He. (author)

Terminal velocities for a large sample of O stars, B supergiants, and Wolf-Rayet stars

International Nuclear Information System (INIS)

Prinja, R.K.; Barlow, M.J.; Howarth, I.D.

1990-01-01

It is argued that easily measured, reliable estimates of terminal velocities for early-type stars are provided by the central velocity asymptotically approached by narrow absorption features and by the violet limit of zero residual intensity in saturated P Cygni profiles. These estimators are used to determine terminal velocities, v(infinity), for 181 O stars, 70 early B supergiants, and 35 Wolf-Rayet stars. For OB stars, the values are typically 15-20 percent smaller than the extreme violet edge velocities, v(edge), while for WR stars v(infinity) = 0.76 v(edge) on average. New mass-loss rates for WR stars which are thermal radio emitters are given, taking into account the new terminal velocities and recent revisions to estimates of distances and to the mean nuclear mass per electron. The relationships between v(infinity), the surface escape velocities, and effective temperatures are examined. 67 refs

Astronomy of binary and multiple stars

International Nuclear Information System (INIS)

Tokovinin, A.A.

1984-01-01

Various types of binary stars and methods for their observation are described in a popular form. Some models of formation and evolution of binary and multiple star systems are presented. It is concluded that formation of binary and multiple stars is a regular stage in the process of star production

The WO Wolf-Rayet stars

International Nuclear Information System (INIS)

Barlow, M.J.

1982-01-01

Sanduleak (1971) has listed five stars, not apparently associated with planetary nebulae, which show very strong O VI 3811.34 A emission. He pointed out that two of them are in the Magellanic Clouds and have absolute magnitudes comparable to those of classical (Population I) Wolf-Rayet stars. O VI emission is known to occur in some classical Wolf-Rayet stars, but not with the extreme strength shown by the Sanduleak stars. The authors have obtained absolute optical spectrophotometry (3100 - 7400 A) of all five of these stars, using the UCL Image Photon Counting System and RGO Spectrograph on the Anglo-Australian Telescope. Their relative flux distributions are shown. Inspection shows that Sand 1 is very lightly reddened, Sand 2 and 3 have intermediate reddening, and Sand 4 and 5 are heavily reddened. IUE ultraviolet spectrophotometry has been obtained of the first three stars; Sand 4 and 5 are too heavily reddened for IUE spectra to be feasible. (Auth.)

Neutron star pulsations and instabilities

International Nuclear Information System (INIS)

Lindblom, L.

2001-01-01

Gravitational radiation (GR) drives an instability in certain modes of rotating stars. This instability is strong enough in the case of the r-modes to cause their amplitudes to grow on a timescale of tens of seconds in rapidly rotating neutron stars. GR emitted by these modes removes angular momentum from the star at a rate which would spin it down to a relatively small angular velocity within about one year, if the dimensionless amplitude of the mode grows to order unity. A pedagogical level discussion is given here on the mechanism of GR instability in rotating stars, on the relevant properties of the r-modes, and on our present understanding of the dissipation mechanisms that tend to suppress this instability in neutron stars. The astrophysical implications of this GR driven instability are discussed for young neutron stars, and for older systems such as low mass x-ray binaries. Recent work on the non-linear evolution of the r-modes is also presented. (author)

GPM GROUND VALIDATION ENVIRONMENT CANADA (EC) MICRO RAIN RADAR (MRR) GCPEX V1

Data.gov (United States)

National Aeronautics and Space Administration — Environment Canada (EC) collected data from the Micro Rain Radar (MRR) during the GPM Cold-season Precipitation Experiment (GCPEx) in Ontario, Canada during the...

LiPF{sub 6}. Synthesis and stability in EC/DMC and PC/DMC mixtures; LiPF{sub 6}. Synthese et stabilite dans les melanges EC/DMC et PC/DMC

Energy Technology Data Exchange (ETDEWEB)

Naejus, R.; Coudert, R.; Lemordant, D. [Laboratoire P.I.M.I.R. EA, Sciences et Techniques, 37 - Tours (France); Willmann, P. [CNES, 31 - Toulouse (France)

1996-12-31

Lithium hexa-fluoro-phosphate LiPF{sub 6} is recommended for the replacement of the toxic LiAsF{sub 6} and the explosive perchlorates (like LiClO{sub 4}) in rechargeable lithium electrochemical generators. The aim of this work is to develop a new method of synthesis of this salt and to check its stability with respect to carbonated solvents: ethylene carbonate (EC), propylene carbonate (PC) and dimethyl-carbonate (DMC) in already optimized EC/DMC and PC/DMC binary mixtures. Two methods using HPF{sub 6} are proposed: the first one uses the direct neutralization of this commercial acid by LiOH in aqueous, alcoholic or acetonitrile environment, while in the second one LiPF{sub 6} is obtained from pyridinium hexa-fluoro-phosphate synthesized from HPF{sub 6} using a new and simple protocol. (J.S.) 24 refs.

LiPF{sub 6}. Synthesis and stability in EC/DMC and PC/DMC mixtures; LiPF{sub 6}. Synthese et stabilite dans les melanges EC/DMC et PC/DMC

Energy Technology Data Exchange (ETDEWEB)

Naejus, R; Coudert, R; Lemordant, D [Laboratoire P.I.M.I.R. EA, Sciences et Techniques, 37 - Tours (France); Willmann, P [CNES, 31 - Toulouse (France)

1997-12-31

Lithium hexa-fluoro-phosphate LiPF{sub 6} is recommended for the replacement of the toxic LiAsF{sub 6} and the explosive perchlorates (like LiClO{sub 4}) in rechargeable lithium electrochemical generators. The aim of this work is to develop a new method of synthesis of this salt and to check its stability with respect to carbonated solvents: ethylene carbonate (EC), propylene carbonate (PC) and dimethyl-carbonate (DMC) in already optimized EC/DMC and PC/DMC binary mixtures. Two methods using HPF{sub 6} are proposed: the first one uses the direct neutralization of this commercial acid by LiOH in aqueous, alcoholic or acetonitrile environment, while in the second one LiPF{sub 6} is obtained from pyridinium hexa-fluoro-phosphate synthesized from HPF{sub 6} using a new and simple protocol. (J.S.) 24 refs.

Activities of the Sofia EC Energy Center in the framework of the THERMIE programme

International Nuclear Information System (INIS)

Latinski, K.

1993-01-01

The European Community Energy Center in Sofia is responsible for the EC implementation of the THERMIE programme. The programme's activities are promotion and dissemination of existing European technologies leading to better energy management and covering the fields of rational use of hydrocarbons, solid fuels and renewable energy sources. Application of these technologies would lead to substantial energy savings resulting in significant financial and environmental benefits. During its one-year operation the EC Energy Centre has organized and performed specific action as energy audits (food and beverage industrial units and buildings), demonstration projects (local heating control in buildings, diesel engine regulation of buses), training courses and seminars (in energy management and in space heating measuring and regulation), workshops (energy conservation in buildings, the bricks and clays sector and the food and beverage sector) and studies (wind energy potential, 'clean' coal technologies potential). Some of these actions have had very encouraging results showing potential energy savings of the order of 10-20% just by application of simple measures and with small additional investment. The activities of the EC Energy Centre in the coming year aimed at electricity savings along the entire line of electricity generation, transmission and consumption are outlined. (author)

How massive the Wolf-Rayet stars are

International Nuclear Information System (INIS)

Niemela, V.S.

1981-01-01

If the Wolf-Rayet stars are produced by the evolution of massive stars with mass loss (Paczynski 1967, Conti 1976) from O stars to WN stars and thereafter to WC stars, then we may expect to observe a correlation of decreasing mean masses in the same sense as the evolution. Information about the masses of WR stars are obtained from studies of binary systems with WR components. (Auth.)

RETIRED A STARS AND THEIR COMPANIONS. III. COMPARING THE MASS-PERIOD DISTRIBUTIONS OF PLANETS AROUND A-TYPE STARS AND SUN-LIKE STARS

International Nuclear Information System (INIS)

Bowler, Brendan P.; Johnson, John Asher; Liu, Michael C.; Marcy, Geoffrey W.; Peek, Kathryn M. G.; Henry, Gregory W.; Fischer, Debra A.; Clubb, Kelsey I.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

2010-01-01

We present an analysis of ∼5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 ∼ * /M sun ∼ +9 -8 %, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} M Jup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN ∝ M α P β dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of α and β for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4σ level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (∼50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets.

Flares on a Bp Star

Science.gov (United States)

Mullan, D. J.

2009-09-01

Two large X-ray flares have been reported from the direction of a magnetic B2p star (σ Ori E). Sanz-Forcada et al. have suggested that the flares did not occur on the B2p star but on a companion of late spectral type. A star which is a candidate for a late-type flare star near σ Ori E has recently been identified by Bouy et al. However, based on the properties of the flares, and based on a recent model of rotating magnetospheres, we argue that, rather than attributing the two flares to a late-type dwarf, it is a viable hypothesis that the flares were magnetic phenomena associated with the rotating magnetosphere of the B2p star itself.

FLARES ON A Bp STAR

International Nuclear Information System (INIS)

Mullan, D. J.

2009-01-01

Two large X-ray flares have been reported from the direction of a magnetic B2p star (σ Ori E). Sanz-Forcada et al. have suggested that the flares did not occur on the B2p star but on a companion of late spectral type. A star which is a candidate for a late-type flare star near σ Ori E has recently been identified by Bouy et al. However, based on the properties of the flares, and based on a recent model of rotating magnetospheres, we argue that, rather than attributing the two flares to a late-type dwarf, it is a viable hypothesis that the flares were magnetic phenomena associated with the rotating magnetosphere of the B2p star itself.

Evolution of star systems supplied by external stars: a model for Galaxy nuclei

International Nuclear Information System (INIS)

Dokuchaev, V.I.; Ozernoj, L.M.; AN SSSR, Moscow. Inst. Yadernykh Issledovanij)

1985-01-01

Extended rarefied environments around the core of a non-isothermic galaxy nucleus can supply the core by both energies and masses of external stars due to relaxation mechanisms. These factors can influence considerably the secular evolution of the core when competing with usual star evaporation from it. Conditions are found under which external environments influence the core evolution much more than star evaporation. This results in expansion of the core instead of its collapse

Evolution of massive stars

International Nuclear Information System (INIS)

Loore, C. de

1984-01-01

The evolution of stars with masses larger than 15 sun masses is reviewed. These stars have large convective cores and lose a substantial fraction of their matter by stellar wind. The treatment of convection and the parameterisation of the stellar wind mass loss are analysed within the context of existing disagreements between theory and observation. The evolution of massive close binaries and the origin of Wolf-Rayet Stars and X-ray binaries is also sketched. (author)

ENERGY STAR Certified Telephones

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Telephony (cordless telephones and VoIP...

Luminosity Variations in Post-AGB Stars

Science.gov (United States)

Mesler, Robert; Henson, G.

2007-12-01

Although much is known about AGB stars and planetary nebulae, relatively little is known about the phase of a star's life in which it transitions between those two states. We have measured the variations in luminosity of a sample of known Post-AGB stars (as well as several candidates) relative to nearby, non-variable stars in order to compare them with theoretical models. The typical behavior of the observed variations is described and an attempt is made to discern whether any periodicity might be present. Luminosity variations were found to be on the order of a few hundredths to a few tenths of a magnitude for the stars that were surveyed, with occasional fluctuations of up to a magnitude. This agrees with current models of Post-AGB stars. Each star fell into one of three categories, which were termed groups 1, 2, and 3. Group 1 stars showed long term, non-periodic luminosity variations on the scale of weeks or longer and were most likely to display some sort of short term, coherent luminosity oscillation (each of which lasted for only a few cycles). Group 2 stars showed erratic, short-term magnitude variations occurring on scales of several days. Group 3 stars showed little or no variation in magnitude. Of the 27 Post-AGB stars that were sampled, five fell into group 1, fifteen fell into group 2, and seven fell into group 3. The luminosity variations tended to be color-independent, and occurred on timescales ranging nearly continuously from a few days to more than a year. No clear periodic behavior was found in any star in our sample. This project was funded by a partnership between the National Science Foundation (NSF AST-0552798), Research Experiences for Undergraduates (REU), and the Department of Defense (DoD) ASSURE (Awards to Stimulate and Support Undergraduate Research Experiences) programs.

Classification of O Stars in the Yellow-Green: The Exciting Star VES 735

Science.gov (United States)

Kerton, C. R.; Ballantyne, D. R.; Martin, P. G.

1999-05-01

Acquiring data for spectral classification of heavily reddened stars using traditional criteria in the blue-violet region of the spectrum can be prohibitively time consuming using small to medium sized telescopes. One such star is the Vatican Observatory emission-line star VES 735, which we have found excites the H II region KR 140. In order to classify VES 735, we have constructed an atlas of stellar spectra of O stars in the yellow-green (4800-5420 Å). We calibrate spectral type versus the line ratio He I lambda4922:He II lambda5411, showing that this ratio should be useful for the classification of heavily reddened O stars associated with H II regions. Application to VES 735 shows that the spectral type is O8.5. The absolute magnitude suggests luminosity class V. Comparison of the rate of emission of ionizing photons and the bolometric luminosity of VES 735, inferred from radio and infrared measurements of the KR 140 region, to recent stellar models gives consistent evidence for a main-sequence star of mass 25 M_solar and age less than a few million years with a covering factor 0.4-0.5 by the nebular material. Spectra taken in the red (6500-6700 Å) show that the stellar Hα emission is double-peaked about the systemic velocity and slightly variable. Hβ is in absorption, so that the emission-line classification is ``(e)''. However, unlike the case of the more well-known O(e) star zeta Oph, the emission from VES 735 appears to be long-lived rather than episodic.

Rotational velocities of low-mass stars

International Nuclear Information System (INIS)

Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

1986-01-01

The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

Moments of inertia of neutron stars

Energy Technology Data Exchange (ETDEWEB)

Greif, Svenja Kim; Hebeler, Kai; Schwenk, Achim [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany)

2016-07-01

Neutron stars are unique laboratories for matter at extreme conditions. While nuclear forces provide systematic constraints on properties of neutron-rich matter up to around nuclear saturation density, the composition of matter at high densities is still unknown. Recent precise observations of 2 M {sub CircleDot} neutron stars made it possible to derive systematic constraints on the equation of state at high densities and also neutron star radii. Further improvements of these constraints require the observation of even heavier neutron stars or a simultaneous measurement of mass and radius of a single neutron star. Since the precise measurement of neutron star radii is an inherently difficult problem, the observation of moment of inertia of neutron stars provides a promising alternative, since they can be measured by pulsar timing experiments. We present a theoretical framework that allows to calculate moments of inertia microscopically, we show results based on state of the art equations of state and illustrate how future measurements of moments of inertia allow to constrain the equation of state and other properties of neutron stars.

Analysis of Well ER-EC-2a Testing, Western Pahute Mesa-Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-2a during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-2a Data Report for Development and Hydraulic Testing.

Supernovae from massive AGB stars

NARCIS (Netherlands)

Poelarends, A.J.T.; Izzard, R.G.; Herwig, F.; Langer, N.; Heger, A.

2006-01-01

We present new computations of the final fate of massive AGB-stars. These stars form ONeMg cores after a phase of carbon burning and are called Super AGB stars (SAGB). Detailed stellar evolutionary models until the thermally pulsing AGB were computed using three di erent stellar evolution codes. The

Unusual Metals in Galactic Center Stars

Science.gov (United States)

Hensley, Kerry

2018-03-01

Far from the galactic suburbs where the Sun resides, a cluster of stars in the nucleus of the Milky Way orbits a supermassive black hole. Can chemical abundance measurements help us understand the formation history of the galactic center nuclear star cluster?Studying Stellar PopulationsMetallicity distributions for stars in the inner two degrees of the Milky Way (blue) and the central parsec (orange). [Do et al. 2018]While many galaxies host nuclear star clusters, most are too distant for us to study in detail; only in the Milky Way can we resolve individual stars within one parsec of a supermassive black hole. The nucleus of our galaxy is an exotic and dangerous place, and its not yet clear how these stars came to be where they are were they siphoned off from other parts of the galaxy, or did they form in place, in an environment rocked by tidal forces?Studying the chemical abundances of stars provides a way to separate distinct stellar populations and discern when and where these stars formed. Previous studies using medium-resolution spectroscopy have revealed that many stars within the central parsec of our galaxy have very high metallicities possibly higher than any other region of the Milky Way. Can high-resolution spectroscopy tell us more about this unusual population of stars?Spectral Lines on DisplayTuan Do (University of California, Los Angeles, Galactic Center Group) and collaborators performed high-resolution spectroscopic observations of two late-type giant starslocated half a parsec from the Milky Ways supermassive black hole.Comparison of the observed spectra of the two galactic center stars (black) with synthetic spectra with low (blue) and high (orange) [Sc/Fe] values. Click to enlarge. [Do et al. 2018]In order to constrain the metallicities of these stars, Do and collaborators compared the observed spectra to a grid of synthetic spectra and used a spectral synthesis technique to determine the abundances of individual elements. They found that

ENERGY STAR Certified Dehumidifiers

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Dehumidifiers that are effective as of October...

Fossil and non-fossil sources of organic carbon (OC and elemental carbon (EC in Göteborg, Sweden

Directory of Open Access Journals (Sweden)

S. Szidat

2009-03-01

Full Text Available Particulate matter was collected at an urban site in Göteborg (Sweden in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC concentrations were 2.1–3.6 μg m⁻³, 1.8–1.9 μg m⁻³, and 2.2–3.0 μg m⁻³ for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC, organic carbon (OC, water-insoluble OC (WINSOC, and water-soluble OC (WSOC were analyzed for ¹⁴C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and ¹⁴C analysis and combined using Latin-hypercube sampling (LHS. For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.

The dance of the double stars

International Nuclear Information System (INIS)

Theokas, A.

1985-01-01

The paper concerns pairs of stars orbiting one another. The evolutionary path model for close binary stars, involving a mass transfer of gases between the stars, is described. The life history of a single star; cataclysmic variables; the algol paradox, matter and lagranges' point; x-ray binaries and bursters; and pulsars; are all briefly discussed. (U.K.)

Environmental effects on star formation in dwarf galaxies and star clusters

Science.gov (United States)

Pasetto, Stefano; Cropper, Mark; fujita, Yutaka; Chiosi, Cesare; Grebel, Eva K.

2015-08-01

We investigate the competitive role of the different dissipative phenomena acting on the onset of star formation history of gravitationally bound system in an external environment.Ram pressure, Kelvin-Helmholtz instability, Rayleigh-Taylor, and tidal forces are accounted separately in an analytical framework and compared in their role in influencing the star forming regions. The two-fluids instability at the interface between a stellar system and its surrounding hotter and less dense environment is related to the star formation processes through a set of differential equations. We present an analytical criterion to elucidate the dependence of star formation in a spherical stellar system on its surrounding environment useful in theoretical interpretations of numerical results as well as observational applications. We show how spherical coordinates naturally enlighten the interpretation of the two-fluids instability in a geometry that directly applies to astrophysical case. Finally, we consider the different signatures of these phenomena in synthetically realized colour-magnitude diagrams of the orbiting system thus investigating the detectability limits of these different effects for future observational projects and their relevance.The theoretical framework developed has direct applications to the cases of dwarf galaxies in galaxy clusters and dwarf galaxies orbiting our Milky Way system, as well as any primordial gas-rich cluster of stars orbiting within its host galaxy.

Massive stars on the verge of exploding: the properties of oxygen sequence Wolf-Rayet stars

NARCIS (Netherlands)

Tramper, F.; Straal, S.M.; Sanyal, D.; Sana, H.; de Koter, A.; Gräfener, G.; Langer, N.; Vink, J.S.; de Mink, S.E.; Kaper, L.

2015-01-01

Context. Oxygen sequence Wolf-Rayet (WO) stars are a very rare stage in the evolution of massive stars. Their spectra show strong emission lines of helium-burning products, in particular highly ionized carbon and oxygen. The properties of WO stars can be used to provide unique constraints on the

Development of novel antibacterial active, HaCaT biocompatible and biodegradable CA-g-P(3HB-EC biocomposites with caffeic acid as a functional entity

Directory of Open Access Journals (Sweden)

H. M. N. Iqbal

2015-09-01

Full Text Available We have developed novel composites by grafting caffeic acid (CA onto the P(3HB-EC based material and laccase from Trametes versicolor was used for grafting purposes. The resulting composites were designated as CA-g-P(3HB-EC i.e., P(3HB-EC (control, 5CA-g-P(3HB-EC, 10CA-g-P(3HB-EC, 15CA-g-P(3HB-EC and 20CA-g-P(3HB-EC. FT-IR (Fourier-transform infrared spectroscopy was used to examine the functional and elemental groups of the control and laccase-assisted graft composites. Evidently, 15CA-g-P(3HB-EC composite exhibited resilient antibacterial activity against Gram-positive and Gram-negative bacterial strains. Moreover, a significant level of biocompatibility and biodegradability of the CA-g-P(3HB-EC composites was also achieved with the human keratinocytes-like HaCaT cells and soil burial evaluation, respectively. In conclusion, the newly developed novel composites with multi characteristics could well represent the new wave of biomaterials for medical applications, and more specifically have promising future in the infection free would dressings, burn and/or skin regeneration field due to their sophisticated characteristics.

StarLogo TNG

Science.gov (United States)

Klopfer, Eric; Scheintaub, Hal; Huang, Wendy; Wendel, Daniel

Computational approaches to science are radically altering the nature of scientific investigatiogn. Yet these computer programs and simulations are sparsely used in science education, and when they are used, they are typically “canned” simulations which are black boxes to students. StarLogo The Next Generation (TNG) was developed to make programming of simulations more accessible for students and teachers. StarLogo TNG builds on the StarLogo tradition of agent-based modeling for students and teachers, with the added features of a graphical programming environment and a three-dimensional (3D) world. The graphical programming environment reduces the learning curve of programming, especially syntax. The 3D graphics make for a more immersive and engaging experience for students, including making it easy to design and program their own video games. Another change to StarLogo TNG is a fundamental restructuring of the virtual machine to make it more transparent. As a result of these changes, classroom use of TNG is expanding to new areas. This chapter is concluded with a description of field tests conducted in middle and high school science classes.

ENERGY STAR Certified Televisions

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Televisions that are effective as of October 30,...

ENERGY STAR Certified Boilers

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Boilers that are effective as of October 1,...

Weighing the Smallest Stars

Science.gov (United States)

2005-01-01

VLT Finds Young, Very Low Mass Objects Are Twice As Heavy As Predicted Summary Thanks to the powerful new high-contrast camera installed at the Very Large Telescope, photos have been obtained of a low-mass companion very close to a star. This has allowed astronomers to measure directly the mass of a young, very low mass object for the first time. The object, more than 100 times fainter than its host star, is still 93 times as massive as Jupiter. And it appears to be almost twice as heavy as theory predicts it to be. This discovery therefore suggests that, due to errors in the models, astronomers may have overestimated the number of young "brown dwarfs" and "free floating" extrasolar planets. PR Photo 03/05: Near-infrared image of AB Doradus A and its companion (NACO SDI/VLT) A winning combination A star can be characterised by many parameters. But one is of uttermost importance: its mass. It is the mass of a star that will decide its fate. It is thus no surprise that astronomers are keen to obtain a precise measure of this parameter. This is however not an easy task, especially for the least massive ones, those at the border between stars and brown dwarf objects. Brown dwarfs, or "failed stars", are objects which are up to 75 times more massive than Jupiter, too small for major nuclear fusion processes to have ignited in its interior. To determine the mass of a star, astronomers generally look at the motion of stars in a binary system. And then apply the same method that allows determining the mass of the Earth, knowing the distance of the Moon and the time it takes for its satellite to complete one full orbit (the so-called "Kepler's Third Law"). In the same way, they have also measured the mass of the Sun by knowing the Earth-Sun distance and the time - one year - it takes our planet to make a tour around the Sun. The problem with low-mass objects is that they are very faint and will often be hidden in the glare of the brighter star they orbit, also when viewed

MASSIVE INFANT STARS ROCK THEIR CRADLE

Science.gov (United States)

2002-01-01

Extremely intense radiation from newly born, ultra-bright stars has blown a glowing spherical bubble in the nebula N83B, also known as NGC 1748. A new NASA Hubble Space Telescope image has helped to decipher the complex interplay of gas and radiation of a star-forming region in a nearby galaxy. The image graphically illustrates just how these massive stars sculpt their environment by generating powerful winds that alter the shape of the parent gaseous nebula. These processes are also seen in our Milky Way in regions like the Orion Nebula. The Hubble telescope is famous for its contribution to our knowledge about star formation in very distant galaxies. Although most of the stars in the Universe were born several billions of years ago, when the Universe was young, star formation still continues today. This new Hubble image shows a very compact star-forming region in a small part of one of our neighboring galaxies - the Large Magellanic Cloud. This galaxy lies only 165,000 light-years from our Milky Way and can easily be seen with the naked eye from the Southern Hemisphere. Young, massive, ultra-bright stars are seen here just as they are born and emerge from the shelter of their pre-natal molecular cloud. Catching these hefty stars at their birthplace is not as easy as it may seem. Their high mass means that the young stars evolve very rapidly and are hard to find at this critical stage. Furthermore, they spend a good fraction of their youth hidden from view, shrouded by large quantities of dust in a molecular cloud. The only chance is to observe them just as they start to emerge from their cocoon - and then only with very high-resolution telescopes. Astronomers from France, the U.S., and Germany have used Hubble to study the fascinating interplay between gas, dust, and radiation from the newly born stars in this nebula. Its peculiar and turbulent structure has been revealed for the first time. This high-resolution study has also uncovered several individual stars

THEODORE, a two-step heating system for the EC/OC determination of radiocarbon (14C) in the environment

International Nuclear Information System (INIS)

Szidat, S.; Jenk, T.M.; Gaeggeler, H.W.; Synal, H.-A.; Hajdas, I.; Bonani, G.; Saurer, M.

2004-01-01

Measurements of 14 C in the organic carbon (OC) and elemental carbon (EC) fractions, respectively, of fine aerosol particles bear the potential to apportion anthropogenic and biogenic emission sources. For this purpose, the system THEODORE (two-step heating system for the EC/OC determination of radiocarbon in the environment) was developed. In this device, OC and EC are transformed into carbon dioxide in a stream of oxygen at 340 and 650 deg. C, respectively, and reduced to filamentous carbon. This is the target material for subsequent accelerator mass spectrometry (AMS) 14 C measurements, which were performed on sub-milligram carbon samples at the PSI/ETH compact 500 kV AMS system. Quality assurance measurements of SRM 1649a, Urban Dust, yielded a fraction of modern f M in total carbon (TC) of 0.522 ± 0.018 (n=5, 95% confidence level) in agreement with reported values. The results for OC and EC are 0.70 ± 0.05 (n=3) and 0.066 ± 0.020 (n=4), respectively

Stars and Star Myths.

Science.gov (United States)

Eason, Oliver

Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

Energy spectrum of flares of the UV Cet stars and physical measunings of several statistical characteristics of these stars

International Nuclear Information System (INIS)

Gershberg, R.E.

1985-01-01

Accounting the observed power character of the energy spectrum of flares of the UV Cet-type stars, several statistical characterisitics of there stars are considered. It is shown that a mean amplitude of flares is mainly determined with an amplitude of the faintest flare that can be registered at the star under consideration and therefore - contrary to tradition - the mean flare amplitude cannot be used as a measure of a flare activity of the star. Mean frequencuy of flares registered at a flare star dependes statisticaally certainly ona an absolute magneitude of the star - contary to wide spread belief, true mean frequencies are higher at brighter stars. On the basis of the Cataloque of flare stars in Pleiades by Haro, Chavira and Gonzalez a luminosity function of therese stars is constructed. Using this function and the revealed dependence of flare mean frequencies on stellar absolute magnitudes, a distribution of flare stars in Pleiades along flare mean frequencies is constructed. This shows that the cluster contains flare stars with mean frequencies of photographically registered flares from 10 -4 to 10 -2 hour -1 or within even narrower interval of frequencies and the total number of such stars in the cluster exceeds 1100

Combgap Promotes Ovarian Niche Development and Chromatin Association of EcR-Binding Regions in BR-C.

Science.gov (United States)

Hitrik, Anna; Popliker, Malka; Gancz, Dana; Mukamel, Zohar; Lifshitz, Aviezer; Schwartzman, Omer; Tanay, Amos; Gilboa, Lilach

2016-11-01

The development of niches for tissue-specific stem cells is an important aspect of stem cell biology. Determination of niche size and niche numbers during organogenesis involves precise control of gene expression. How this is achieved in the context of a complex chromatin landscape is largely unknown. Here we show that the nuclear protein Combgap (Cg) supports correct ovarian niche formation in Drosophila by controlling ecdysone-Receptor (EcR)- mediated transcription and long-range chromatin contacts in the broad locus (BR-C). Both cg and BR-C promote ovarian growth and the development of niches for germ line stem cells. BR-C levels were lower when Combgap was either reduced or over-expressed, indicating an intricate regulation of the BR-C locus by Combgap. Polytene chromosome stains showed that Cg co-localizes with EcR, the major regulator of BR-C, at the BR-C locus and that EcR binding to chromatin was sensitive to changes in Cg levels. Proximity ligation assay indicated that the two proteins could reside in the same complex. Finally, chromatin conformation analysis revealed that EcR-bound regions within BR-C, which span ~30 KBs, contacted each other. Significantly, these contacts were stabilized in an ecdysone- and Combgap-dependent manner. Together, these results highlight Combgap as a novel regulator of chromatin structure that promotes transcription of ecdysone target genes and ovarian niche formation.

Mass loss from Wolf-Rayet stars

International Nuclear Information System (INIS)

Willis, A.J.

1982-01-01

Recent results relating to the stellar winds and mass loss rates of the WR stars are reviewed, emphasising new data and their interpretation acquired at UV, IR and Radio wavelengths. The subject is discussed under the headings: physical and chemical properties of WR stars (effective temperatures and radiative luminosities; masses; chemical abundances); velocity, ionisation and excitation structure of WR winds; mass loss rates of WR stars; mass loss properties of WR stars in the LMC; comparisons with theoretical models of mass loss; ring nebulae around WR stars; conclusions. (author)

The Dark Side of Neutron Stars

DEFF Research Database (Denmark)

Kouvaris, Christoforos

2013-01-01

We review severe constraints on asymmetric bosonic dark matter based on observations of old neutron stars. Under certain conditions, dark matter particles in the form of asymmetric bosonic WIMPs can be eectively trapped onto nearby neutron stars, where they can rapidly thermalize and concentrate...... in the core of the star. If some conditions are met, the WIMP population can collapse gravitationally and form a black hole that can eventually destroy the star. Based on the existence of old nearby neutron stars, we can exclude certain classes of dark matter candidates....

Energy policy and the scope of action of the EC; Die energiepolitischen Handlungsmoeglichkeiten der EG

Energy Technology Data Exchange (ETDEWEB)

Brand, E. [Universitaet Lueneburg, Lueneburg (Germany); Witthohn, A. [IHK Hannover (Germany)

2002-04-01

This contribution examines the legal basis of authorization and the scope of action of the European legislator with respect to legislation on the energy policy of the EC. The analysis starts with summarising the evolution of the primary law, looking inter alia at the constitutent treaties of the ECSC, EURATOM, and the EEC, and discusses further developments and treaties, as there is no specific, uniform basis of legislative power of the EC in the energy sector of EC. Subsequently, the basis for and secondary law making is discussed, the concluding part of the article giving an outlook on the future. (orig./CB) [German] Zentrale Frage des folgenden Beitrags ist, woraus der europaeische Gesetzgeber seine Kompetenz im Energiebereich ableitet und wie weit seine Regelungen in dem Bereich gehen duerfen. Um diese Fragen zu beantworten, wird zunaechst die Entwicklung des europaeischen Primaerrechts bzw. der Gruendungsvertraege im Energiebereich beleuchtet und werden die einschlaegigen Ermaechtigungsgrundlagen dargestellt. Im Anschluss daran stehen dann die wichtigsten sekundaerrechtlichen Regelungen im Mittelpunkt. Abschliessend wird ein Ausblick auf die weitere Entwicklung gegeben. (orig./CB)

ENERGY STAR Certified Displays

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Displays that are effective as of July 1, 2016....

Observations of central stars

International Nuclear Information System (INIS)

Lutz, J.H.

1978-01-01

Difficulties occurring in the observation of central stars of planetary nebulae are reviewed with emphasis on spectral classifications and population types, and temperature determination. Binary and peculiar central stars are discussed. (U.M.G.)

DO HYDROGEN-DEFICIENT CARBON STARS HAVE WINDS?

International Nuclear Information System (INIS)

Geballe, T. R.; Rao, N. Kameswara; Clayton, Geoffrey C.

2009-01-01

We present high resolution spectra of the five known hydrogen-deficient carbon (HdC) stars in the vicinity of the 10830 A line of neutral helium. In R Coronae Borealis (RCB) stars the He I line is known to be strong and broad, often with a P Cygni profile, and must be formed in the powerful winds of those stars. RCB stars have similar chemical abundances as HdC stars and also share greatly enhanced 18 O abundances with them, indicating a common origin for these two classes of stars, which has been suggested to be white dwarf mergers. A narrow He I absorption line may be present in the hotter HdC stars, but no line is seen in the cooler stars, and no evidence for a wind is found in any of them. The presence of wind lines in the RCB stars is strongly correlated with dust formation episodes so the absence of wind lines in the HdC stars, which do not make dust, is as expected.

Risk assesment in the context of EC directives on genetically modified organisms

Energy Technology Data Exchange (ETDEWEB)

Meer, P.J. van der [Ministry for the Environment (Netherlands)

1992-07-01

The introduction of these new molecular technologies initiated an international discussion on the safety in biotechnology. In 1974 one of the pioneers of this new technology, Paul Berg, expressed his view on the potential risks of recombinant DNA applications in the famous 'Berg letter', leading to a self-imposed moratorium on certain experiments. Following the Berg letter and the Asilomar convention, much international attention has been given to the question of safety in biotechnology. This attention resulted in hundreds of documents, research programmes, guidelines and regulations. This resulted, among others, in two EC Directives on genetically modified organisms: the EC Directive 90/219/EEC on the contained use of genetically modified micro-organisms, and Directive 90/220/EEC on the release of genetically modified organisms. These directives lay down a system for harmonization of risk assessment and risk management with regard to the safety for human health and the environment.

Risk assesment in the context of EC directives on genetically modified organisms

International Nuclear Information System (INIS)

Meer, P.J. van der

1992-01-01

The introduction of these new molecular technologies initiated an international discussion on the safety in biotechnology. In 1974 one of the pioneers of this new technology, Paul Berg, expressed his view on the potential risks of recombinant DNA applications in the famous 'Berg letter', leading to a self-imposed moratorium on certain experiments. Following the Berg letter and the Asilomar convention, much international attention has been given to the question of safety in biotechnology. This attention resulted in hundreds of documents, research programmes, guidelines and regulations. This resulted, among others, in two EC Directives on genetically modified organisms: the EC Directive 90/219/EEC on the contained use of genetically modified micro-organisms, and Directive 90/220/EEC on the release of genetically modified organisms. These directives lay down a system for harmonization of risk assessment and risk management with regard to the safety for human health and the environment

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment

Science.gov (United States)

Javadi, A.; van Loon, J. Th

2017-06-01

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars (LPVs) were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Here we present our methodology and describe results for the central square kiloparsec of M33 [1-4] and disc of M33 [5-8].

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment

International Nuclear Information System (INIS)

Javadi, A; Van Loon, J Th

2017-01-01

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars (LPVs) were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Here we present our methodology and describe results for the central square kiloparsec of M33 [1–4] and disc of M33 [5–8]. (paper)

Agricultural price and income policy in the EC : alternative policies and their implications

NARCIS (Netherlands)

Meester, G.

1980-01-01

Alternative forms of income policy without direct supply control. Alternative forms of income policy with direct supply control: quota arrangements. The influence of EC policy on the world market prices of agricultural produce

THE Be STAR SPECTRA (BeSS) DATABASE

International Nuclear Information System (INIS)

Neiner, C.; De Batz, B.; Cochard, F.; Floquet, M.; Mekkas, A.; Desnoux, V.

2011-01-01

Be stars vary on many timescales, from hours to decades. A long time base of observations to analyze certain phenomena in these stars is therefore necessary. Collecting all existing and future Be star spectra into one database has thus emerged as an important tool for the Be star community. Moreover, for statistical studies, it is useful to have centralized information on all known Be stars via an up-to-date catalog. These two goals are what the Be Star Spectra (BeSS, http://basebe.obspm.fr) database proposes to achieve. The database contains an as-complete-as-possible catalog of known Be stars with stellar parameters, as well as spectra of Be stars from all origins (any wavelength, any epoch, any resolution, etc.). It currently contains over 54,000 spectra of more than 600 different Be stars among the ∼2000 Be stars in the catalog. A user can access and query this database to retrieve information on Be stars or spectra. Registered members can also upload spectra to enrich the database. Spectra obtained by professional as well as amateur astronomers are individually validated in terms of format and science before being included in BeSS. In this paper, we present the database itself as well as examples of the use of BeSS data in terms of statistics and the study of individual stars.

A Heavy Flavor Tracker for STAR

Energy Technology Data Exchange (ETDEWEB)

Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Miller,M.; Surrow, B.; Van Nieuwenhuizen G.; Bieser, F.; Gareus, R.; Greiner,L.; Lesser, F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

2005-03-14

We propose to construct a Heavy Flavor Tracker (HFT) for theSTAR experiment at RHIC. The HFT will bring new physics capabilities toSTAR and it will significantly enhance the physics capabilities of theSTAR detector at central rapidities. The HFT will ensure that STAR willbe able to take heavy flavor data at all luminosities attainablethroughout the proposed RHIC II era.

A Heavy Flavor Tracker for STAR

Energy Technology Data Exchange (ETDEWEB)

Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow,B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser,F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

2005-03-14

We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

A Heavy Flavor Tracker for STAR

International Nuclear Information System (INIS)

Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi, A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow, B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser, F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

2005-01-01

We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era

MicroRNA-281 regulates the expression of ecdysone receptor (EcR) isoform B in the silkworm, Bombyx mori

Science.gov (United States)

Hundreds of Bombyx mori miRNAs had been identified in recent years, but their function in vivo remains poorly understood. The silkworm EcR gene (BmEcR) has three transcriptional isoforms, A, B1 and B2. Isoform sequences are different in the 3’UTR region of the gene, which is the case only in insects...

Birth preparedness and complication readiness among pregnant ...

African Journals Online (AJOL)

government and donor agency funding for safe motherhood programmes should focus on female ... were of child-bearing age, in 2011.[7] The ..... Projected population and work plan for routine immunization, 2011. ... Adeleye OA, Chiwuzie J. 'He does his own and walks away': Perception about male attitudes and practices.

76 FR 78882 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Affirmative Preliminary Determination of...

Science.gov (United States)

2011-12-20

... included within the scope. On August 16, 2011, ArcelorMittal USA LLC, Gerdau Ameristeel U.S. Inc, Rocky... are properly considered ``minor,'' the legislative history of this provision indicates there are... 8, 2011.\\7\\ \\7\\ Deacero has never been individually examined by the Department during the history of...

SIPSMetGen: It's Not Just For Aircraft Data and ECS Anymore.

Science.gov (United States)

Schwab, M.

2015-12-01

The SIPSMetGen utility, developed for the NASA EOSDIS project, under the EED contract, simplified the creation of file level metadata for the ECS System. The utility has been enhanced for ease of use, efficiency, speed and increased flexibility. The SIPSMetGen utility was originally created as a means of generating file level spatial metadata for Operation IceBridge. The first version created only ODL metadata, specific for ingest into ECS. The core strength of the utility was, and continues to be, its ability to take complex shapes and patterns of data collection point clouds from aircraft flights and simplify them to a relatively simple concave hull geo-polygon. It has been found to be a useful and easy to use tool for creating file level metadata for many other missions, both aircraft and satellite. While the original version was useful it had its limitations. In 2014 Raytheon was tasked to make enhancements to SIPSMetGen, this resulted a new version of SIPSMetGen which can create ISO Compliant XML metadata; provides optimization and streamlining of the algorithm for creating the spatial metadata; a quicker runtime with more consistent results; a utility that can be configured to run multi-threaded on systems with multiple processors. The utility comes with a java based graphical user interface to aid in configuration and running of the utility. The enhanced SIPSMetGen allows more diverse data sets to be archived with file level metadata. The advantage of archiving data with file level metadata is that it makes it easier for data users, and scientists to find relevant data. File level metadata unlocks the power of existing archives and metadata repositories such as ECS and CMR and search and discovery utilities like Reverb and Earth Data Search. Current missions now using SIPSMetGen include: Aquarius, Measures, ARISE, and Nimbus.

CHAPTER 1. Miktoarm Star (µ-Star) Polymers: A Successful Story

KAUST Repository

Iatrou, Hermis; Avgeropoulos, Apostolos; Sakellariou, Georgios; Pitsikalis, Marinos; Hadjichristidis, Nikolaos

2017-01-01

The term miktoarm stars (coming from the Greek word μιτσ meaning mixed) was adopted in 1992 by our group for star polymers with either chemical (e.g., AB), molecular weight (e.g., AA′), topological (e.g., (AB)-junction-(BA)), or functional group (e.g., AA) asymmetry. The first μ-stars synthesized by anionic polymerization, on the one hand, guided polymer chemists working with other types of polymerization techniques towards this direction and, on the other hand, helped polymer physicists to carry out experiments and develop theories on the influence of the architecture on the morphology of block copolymers. Synthetic strategies based on anionic polymerization, as well as a few examples showing the influence of the miktoarm structure on the morphology of block copolymers, are reviewed in this chapter.

CHAPTER 1. Miktoarm Star (µ-Star) Polymers: A Successful Story

KAUST Repository

Iatrou, Hermis

2017-04-13

The term miktoarm stars (coming from the Greek word μιτσ meaning mixed) was adopted in 1992 by our group for star polymers with either chemical (e.g., AB), molecular weight (e.g., AA′), topological (e.g., (AB)-junction-(BA)), or functional group (e.g., AA) asymmetry. The first μ-stars synthesized by anionic polymerization, on the one hand, guided polymer chemists working with other types of polymerization techniques towards this direction and, on the other hand, helped polymer physicists to carry out experiments and develop theories on the influence of the architecture on the morphology of block copolymers. Synthetic strategies based on anionic polymerization, as well as a few examples showing the influence of the miktoarm structure on the morphology of block copolymers, are reviewed in this chapter.

Flare stars in Pleiades. 6

International Nuclear Information System (INIS)

Mirzoyan, L.V.; Chavushyan, O.S.; Oganyan, G.B.; Ambaryan, V.V.; Garibdzhanyan, A.T.; Melikyan, N.D.; Natsvlishvili, R.Sh.; AN Gruzinskoj SSR, Abastumani. Abastumanskaya Astrofizicheskaya Observatoriya)

1981-01-01

The results of photographic observations of stellar flares in the Pleiades region carried out at the Byurakan and Abastumani astrophysical observatories during 1976-1979 are given. On the basis of these observations 17 new flare stars have been found. Total number of all known flare stars in the Pleiades region on 1 June 1980 reached 524, and the number of all flares-1244. The observational data on distribution of flare stars according to the observed flares is satisfactorily represented by the average frequency function introduced by V.A.Ambartsumian. The total number of the flare stars in the Pleiades is of the order of 1100. Using three telescopes, synchronous photographic observations of stellar flares in Pleiades in U, B, V, system are carried out. The colour indices U-B and B-V of stellar flares in periods including the maximum of the flare slightly differ from that of photoelectrically defined for flares of UV Ceti type stars, which testifies the physical relationship of flare stars in Pleiades and in the vicinity of the Sun [ru

Analysis of the pelE promoter in Erwinia chrysanthemi EC16.

Science.gov (United States)

Gold, S; Nishio, S; Tsuyumu, S; Keen, N T

1992-01-01

The pelE gene of Erwinia chrysanthemi strain EC16 encodes an extracellular pectate lyase protein that is important in virulence on plants. Control of pelE expression is complex, because the gene is regulated by catabolite repression, substrate induction, and growth-phase inhibition. A Tn7-lux reporter gene system was employed to define DNA sequences comprising the pelE promoter. When EC16 cells were grown on medium containing sodium polypectate, pelE transcriptional start sites were observed only at 95 and 96 bases upstream of the translational start site. However, DNA sequences required for pelE expression were also shown by deletion analysis to reside between 196 and 215 base pairs upstream of the translational start site. In addition to these upstream elements, two putative operator sequences that interact with negative regulatory factors occurred downstream of the transcriptional start. Finally, deletion of three bases from a putative catabolite gene activator protein binding site in the pelE promoter eliminated activity. The data demonstrate that the pelE promoter is complex and suggest that it interacts with several regulatory proteins.