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Sample records for binary exo 0748-676

  1. XMM-Newton observations of the low-mass X-ray binary EXO 0748-676 in quiescence

    NARCIS (Netherlands)

    Trigo, M. Diaz; Boirin, L.; Costantini, E.; Mendez, M.; Parmar, A.

    2011-01-01

    The neutron star low-mass X-ray binary EXO 0748-676 started a transition from outburst to quiescence in August 2008, after more than 24 years of continuous accretion. The return of the source to quiescence has been monitored extensively by several X-ray observatories. Here, we report on four XMM-New

  2. Search for pulsations in the LMXB EXO 0748-676

    Institute of Scientific and Technical Information of China (English)

    Chetana Jain; Biswajit Paul

    2011-01-01

    We present here results from our search for X-ray pulsations of the neutron star in the low mass X-ray binary EXO 0748-676 at a frequency near the burstoscillation frequency of 44.7 Hz.Using the observations made with the Proportional Counter Array onboard the Rossi X-ray Timing Explorer, we did not find any pulsations in the frequency band of 44.4 Hz to 45.0 Hz and obtained a 3σ upper limit of 0.47% on the pulsed fraction for any possible underlying pulsation in this frequency band.We also discuss the importance of EXO 0748-676 as a promising source for the detection of Gravitational Waves.

  3. RXTE and Swift confirm decay to quiescence of EXO0748-676

    NARCIS (Netherlands)

    M. Wolff; P. Ray; K. Wood; R. Wijnands

    2008-01-01

    EXO0748-676, a low mass X-ray binary system that shows regular total X-ray eclipses with a period of 3.82 hours, until August 2008 maintained a relatively steady X-ray flux of ~8 mcrab implying a luminosity of ~1.3E36 ergs/s (2-10 keV) at a distance of 7.7 kpc (Wolff et al. 2005, ApJ, v.632, p.1099)

  4. Discovery of the Neutron Star Spin Frequency in EXO 0748-676

    Science.gov (United States)

    Villarreal, Adam R.; Strohmayer, Tod E.

    2004-01-01

    We report the results of a search for burst oscillations during thermonuclear X-ray bursts from the low mass X-ray binary (LMXB) EXO 0748-676. With the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) we have detected a 45 Hz oscillation in the average power spectrum of 38 thermonuclear X-ray bursts from this source. We computed power spectra with 1 Hz frequency resolution for both the rising and decaying portions of 38 X-ray bursts from the public RXTE archive. We averaged the 1 Hz power spectra and detected a significant signal at 45 Hz in the decaying phases of the bursts. The signal is detected at a significance level of 4 x 10 (exp -8) similar signal was detected in the rising intervals. The oscillation peak is unresolved at 1 Hz frequency resolution, indicating an oscillation quality factor, Q = nu (sub 0)/Delta nu (sub fwhm) greater than 45, and the average signal amplitude is approximately equal to 3% (rms) The detection of 45 Hz burst oscillations from EXO 0748-676 provides compelling evidence that this is the neutron star spin frequency in this system. We use the inferred spin frequency to model the widths of absorption lines from the neutron star surface and show that the widths of the absorption lines from EXO 0748-676 recently reported by Cottam et al. are consistent with a 45 Hz spin frequency as long as the neutron star radius is in the range from about 9.5 - 15 km. With a known spin frequency, precise modelling of the line profiles from EXO 0748-676 holds great promise for constraining the dense matter equation of state.

  5. What Can the Redshift Observed in EXO 0748-676 Tell Us?

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The mass-radius relations for bare and crusted strange stars are calcu-lated with the bag model. Comparing these relations with the observed one derivedfrom the redshift of EXO 0748-676, we come to the conclusion that it is incorrectto say that EXO 0748-676 cannot be a strange star. Various strange star modelscan show that EXO 0748-676 could have a mass of (1.3 ~ 1.7) M and a radius of(8.4 ~ 11.4) km. It is proposed that a proportion of nascent strange stars could bebare and have masses ~ 0.1 M , and their masses increased over a long period ofaccretion.

  6. The distance and internal composition of the neutron star in EXO 0748-676 with XMM-Newton

    CERN Document Server

    Zhang, Guobao; Jonker, Peter; Hiemstra, Beike

    2010-01-01

    Recently, the neutron star X-ray binary EXO 0748-676 underwent a transition to quiescence. We analyzed an XMM-Newton observation of this source in quiescence, where we fitted the spectrum with two different neutron-star atmosphere models. From the fits we constrained the allowed parameter space in the mass-radius diagram for this source for an assumed range of distances to the system. Comparing the results with different neutron-star equations of state, we constrained the distance to EXO 0748-676. We found that the EOS model 'SQM1' is rejected by the atmosphere model fits for the known distance, and the 'AP3' and 'MS1' is fully consistent with the known distance.

  7. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    Science.gov (United States)

    Degenaar, N.; Wolff, M. T.; Ray, P. S.; Wood, K. S.; Homan, J.; Lewin, W. H. G.; Jonker, P. G.; Cackett, E. M.; Miller, J. M.; Brown, E. F.; Wijnands, R.

    2011-04-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 started a transition from outburst to quiescence, after it actively accreted for more than 24 yr. In a previous work, we discussed Chandra and Swift observations obtained during the first 5 months of this transition. Here, we report on further X-ray observations of EXO 0748-676, extending the quiescent monitoring to 1.6 yr. Chandra and XMM-Newton data reveal quiescent X-ray spectra composed of a soft, thermal component that is well fitted by a neutron star atmosphere model. An additional hard power-law tail is detected that changes non-monotonically over time, contributing between 4 and 20 per cent to the total unabsorbed 0.5-10 keV flux. The combined set of Chandra, XMM-Newton and Swift data reveals that the thermal bolometric luminosity fades from ˜ 1 × 1034 to 6 × 1033 (D/7.4 kpc)2 erg s -1, whereas the inferred neutron star effective temperature decreases from ˜124 to 109 eV. We interpret the observed decay as cooling of the neutron star crust and show that the fractional quiescent temperature change of EXO 0748-676 is markedly smaller than observed for three other neutron star X-ray binaries that underwent prolonged accretion outbursts.

  8. Disentangling x-ray reprocessing sites in exo 0748{676

    Directory of Open Access Journals (Sweden)

    R. I. Hynes

    2004-01-01

    Full Text Available Presentamos los primeros resultados de un estudio coordinado en m ultiples longitudes de onda de la estrella de neutrones de la binaria de baja masa de rayos X, EXO 0748-676 (UY Vol. Se obtuvieron datos UV r apidos, de rayos X y opticos, incluyendo tanto informaci on espectral como temporal. Discutimos c omo este estudio nos permite indagar sobre cu al es la distribuci on de temperatura dentro de la binaria y por lo tanto, sobre la geometr a y la e ciencia de la irradiaci on de rayos X

  9. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    CERN Document Server

    Degenaar, N; Ray, P S; Wood, K S; Homan, J; Lewin, W H G; Jonker, P G; Cackett, E M; Miller, J M; Brown, E F; Wijnands, R

    2010-01-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 started a transition from outburst to quiescence, after it had been actively accreting for more than 24 years. In a previous work, we discussed Chandra and Swift observations obtained during the first five months after this transition. Here, we report on further X-ray observations of EXO 0748-676, extending the quiescent monitoring to 1.6 years. Chandra and XMM-Newton data reveal quiescent X-ray spectra composed of a soft, thermal component that is well-fitted by a neutron star atmosphere model. An additional hard powerlaw tail is detected that changes non-monotonically over time, contributing between 4 and 20 percent to the total unabsorbed 0.5-10 keV flux. The combined set of Chandra, XMM-Newton and Swift data reveals that the thermal bolometric luminosity fades from ~1E34 to 6E33 (d/7.4 kpc)^2 erg/s, whereas the inferred neutron star effective temperature decreases from ~124 to 109 eV. We interpret the observe...

  10. Chandra and Swift observations of the quasi-persistent neutron star transient EXO 0748-676 in quiescence

    CERN Document Server

    Degenaar, N; Wolff, M T; Ray, P S; Wood, K S; Homan, J; Lewin, W H G; Jonker, P G; Cackett, E M; Miller, J M; Brown, E F

    2008-01-01

    The quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 recently returned to quiescence following an accretion outburst that lasted more than 24 years. We report on 2 Chandra and 5 Swift observations performed approximately one to two months after the transition from outburst to quiescence. The Chandra observations detect the source at a bolometric thermal luminosity of ~9.8E33 (d/7.4 kpc) erg/s. The spectrum is composed of a soft, thermal component that fits to a neutron star atmosphere model with kT^inf~0.11 keV, combined with a hard powerlaw tail that contributes ~20% of the total 0.5-10 keV quiescent flux. Several Swift observations were obtained 1-2 weeks before the Chandra observations and another series was taken approximately 2 weeks thereafter. The combined Chandra/Swift data set reveals a relatively hot and luminous quiescent system with a temperature of kT^inf~0.11-0.13 keV and a bolometric thermal luminosity that slightly decreased from ~1.6E34 to ~8.3E33 (d/7.4 kpc) er...

  11. The mass, radius, distance and cooling of the neutron star in EXO 0748-676 in quiescence with XMM-Newton

    Science.gov (United States)

    Cheng, Zheng; Mendez, Mariano; Costantini, Elisa; Diaz Trigo, Maria

    2016-07-01

    We present the spectral analysis of four XMM-Newton observations of the neutron-star low-mass X-ray binary EXO 0748-676 in quiescence, taken between 2009 and 2013. We fit the spectra with an absorbed neutron-star atmosphere model, without the need for a high-energy (power-law) component, with a 95 per cent confidence upper limit of 1 per cent to the contribution of the power law to the total flux of the source in the 0.2-10.0 keV band. We find a significant emission line at around 0.5 keV in the spectra of the three CCD cameras on board XMM-Newton of all four observations; the line, which we tentatively identify as Lyα emission from NVII, is moderately broad, σ ≈ 0.17 keV, and contributes ˜10-14 per cent of the total flux in the 0.2-10 keV band. The temperature of the neutron star in EXO 0748-676 has decreased significantly compared to the previous XMM-Newton observation, with the cooling curve being consistent with either an exponential decay plus a constant, a power law or a broken power-law. We fitted the spectra with a neutron-star atmosphere model that takes into account the observed peak flux of photospheric radius expansion (PRE) bursts to constrain the neutron-star mass, radius and distance self-consistently. Using this model we carried out MCMC simulations assuming a uniform prior for the inclination angle of the system (which accounts for anisotropy in the emission at the peak of the bursts) and for the hydrogen fraction of the fuel during the PRE bursts. We find that M _{ns} = 1.87 ^{+0.69}_{-0.32} M⊙, R_{ns} = 8.5^{+3.2}_{-1.3} km and D = 5.4^{+2.4}_{-1.2} kpc (99% confidence level), which is inconsistent with quark-bearing equations of state for this neutron star.

  12. Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust

    NARCIS (Netherlands)

    N. Degenaar; M.T. Wolff; P.S. Ray; K.S. Wood; J. Homan; W.H.G. Lewin; P.G. Jonker; E.M. Cackett; J.M. Miller; E.F. Brown; R. Wijnands

    2011-01-01

    In late 2008, the quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748−676 started a transition from outburst to quiescence, after it actively accreted for more than 24 yr. In a previous work, we discussed Chandra and Swift observations obtained during the first 5 months of th

  13. The distance and internal composition of the neutron star in EXO 0748−676 with XMM-Newton

    NARCIS (Netherlands)

    Zhan, Guobao; Méndez, Mariano; Jonker, Peter; Hiemstra, Beike

    2011-01-01

    Recently, the neutron star X-ray binary EXO 0748-676 underwent a transition to quiescence. We analyzed an XMM-Newton observation of this source in quiescence, where we fitted the spectrum with two different neutron-star atmosphere models. From the fits we constrained the allowed parameter space in t

  14. Chandra and Swift observations of the quasi-persistent neutron star transient EXO 0748−676 back to quiescence

    NARCIS (Netherlands)

    N. Degenaar; R. Wijnands; M.T. Wolff; P.S. Ray; K.S. Wood; J. Homan; W.H.G. Lewin; P.G. Jonker; E.M. Cackett; J.M. Miller; E.F. Brown

    2009-01-01

    The quasi-persistent neutron star X-ray transient and eclipsing binary EXO 0748-676 recently started the transition to quiescence following an accretion outburst that lasted more than 24 years. We report on two Chandra and 12 Swift observations performed within five months after the end of the outbu

  15. The high optical polarization in the Be/X-ray binary EXO 2030+375

    CERN Document Server

    Reig, P; Papadakis, I; Kylafis, N; Tassis, K

    2014-01-01

    Polarization in classical Be stars results from Thomson scattering of the unpolarized light from the Be star in the circumstellar disc. Theory and observations agree that the maximum degree of polarization from isolated Be stars is < 4%. We report on the first optical polarimetric observations of the Be/X-ray binary EXO\\,2030+375. We find that the optical (R band) light is strongly linearly polarized with a degee of polarization of 19%, the highest ever measured either in a classical or Be/X-ray binary. We argue that the interstellar medium cannot account for this high polarization degree and that a substantial amount must be intrinsic to the source. We propose that it may result from the alignment of non-spherical ferromagnetic grains in the Be star disc due to the strong neutron star magnetic field.

  16. High-Resolution spectroscopy of the low-mass X-ray binary EXO 0748-67

    CERN Document Server

    Cottam, J; Brinkman, A C; Den Herder, J M; Erd, Christian

    2001-01-01

    We present initial results from observations of the low-mass X-ray binary EXO 0748-67 with the Reflection Grating Spectrometer on board the XMM-Newton Observatory. The spectra exhibit discrete structure due to absorption and emission from ionized neon, oxygen, and nitrogen. We use the quantitative constraints imposed by the spectral features to develop an empirical model of the circumsource material. This consists of a thickened accretion disk with emission and absorption in the plasma orbiting high above the binary plane. This model presents challenges to current theories of accretion in X-ray binary systems.

  17. Hysteresis in the spectral states of the neutron star low-mass X-ray binary EXO 1745-248

    CERN Document Server

    Mukherjee, Arunava

    2011-01-01

    We study the low-frequency timing properties and the spectral state evolution of the transient neutron star low-mass X-ray binary EXO 1745-248 using the entire Rossi X-ray Timing Explorer Proportional Counter Array data. We tentatively conclude that EXO 1745-248 is an atoll source, and report the discovery of a ~ 0.45 Hz low-frequency quasi-periodic oscillation and ~ 10 Hz peaked noises. If it is an atoll, this source is unusual because (1) instead of a `C'-like curve, it traced a clear overall clockwise hysteresis curve in each of the colour-colour diagram and the hardness-intensity diagram; and (2) the source took at least 2.5 months to trace the softer banana state, as opposed to a few hours to a day, which is typical for an atoll source. The shape of the hysteresis track was intermediate between the characteristic `q'-like curves of several black hole systems and `C'-like curves of atolls, implying that EXO 1745-248 is an important source for the unification of the black hole and neutron star accretion pr...

  18. Disc-Jet Coupling in the Terzan 5 Neutron Star X-ray Binary EXO 1745$-$248

    CERN Document Server

    Tetarenko, A J; Sivakoff, G R; Tremou, E; Linares, M; Tudor, V; Miller-Jones, J C A; Heinke, C O; Chomiuk, L; Strader, J; Altamirano, D; Degenaar, N; Maccarone, T; Patruno, A; Sanna, A; Wijnands, R

    2016-01-01

    We present the results of VLA, ATCA, and Swift XRT observations of the 2015 outburst of the transient neutron star X-ray binary (NSXB), EXO 1745$-$248, located in the globular cluster Terzan 5. Combining (near-) simultaneous radio and X-ray measurements we measure a correlation between the radio and X-ray luminosities of $L_R\\propto L_X^\\beta$ with $\\beta=1.68^{+0.10}_{-0.09}$, linking the accretion flow (probed by X-ray luminosity) and the compact jet (probed by radio luminosity). While such a relationship has been studied in multiple black hole X-ray binaries (BHXBs), this work marks only the third NSXB with such a measurement. Constraints on this relationship in NSXBs are strongly needed, as comparing this correlation between different classes of XB systems is key in understanding the properties that affect the jet production process in accreting objects. Our best fit disc-jet coupling index for EXO 1745$-$248 is consistent with the measured correlation in NSXB 4U 1728$-$34 ($\\beta=1.5\\pm 0.2$) but inconsi...

  19. JEM-X observations of the Be/X-ray binary EXO 2030+375

    DEFF Research Database (Denmark)

    Nunez, S.M.; Reig, P.; Blay, P.

    2003-01-01

    We have used data from the Joint European Monitor (JEM-X) to perform an X-ray spectral and timing analysis of the 42-s transient pulsar EXO 2030+375 during an X-ray outburst. X-ray pulsations are clearly detected with an average pulse period of 41.66+/-0.05 s and an average pulse fraction of 60%....

  20. An Exo-Jupiter candidate in the eclipsing binary FL Lyr

    Science.gov (United States)

    Kozyreva, V. S.; Bogomazov, A. I.; Demkov, B. P.; Zotov, L. V.; Tutukov, A. V.

    2015-11-01

    Light curves of the eclipsing binary FL Lyr acquired by the Kepler space telescope are analyzed. Eclipse timing measurements for FL Lyr testify to the presence of a third body in the system. Preliminary estimates of its mass and orbital period are ≳2MJ and ≳7 yrs. The times of primary minimum in the light curve of FL Lyr during the operation of the Kepler mission are presented.

  1. An Exo-Jupiter Candidate in the Eclipsing Binary FL Lyr

    CERN Document Server

    Kozyreva, V S; Demkov, B P; Zotov, L V; Tutukov, A V

    2015-01-01

    Light curves of the eclipsing binary FL Lyr acquired by the Kepler space telescope are analyzed. Eclipse timing measurements for FL Lyr testify to the presence of a third body in the system. Preliminary estimates of its mass and orbital period are > 2M_Jupiter and > 7 yrs. The times of primary minimum in the light curve of FL Lyr during the operation of the Kepler mission are presented.

  2. Status of EXO-200

    CERN Document Server

    Ackerman, Nicole

    2009-01-01

    EXO-200 is the first phase of the Enriched Xenon Observatory (EXO) experiment, which searches for neutrinoless double beta decay in 136Xe to measure the mass and probe the Majorana nature of the neutrino. EXO-200 consists of 200 kg of liquid Xe enriched to 80% in 136Xe in an ultra-low background TPC. Energy resolution is enhanced through the simultaneous collection of scintillation light using Large Area Avalanche Photodiodes (LAAPD's) and ionization charge. It is being installed at the WIPP site in New Mexico, which provides a 2000 meter water-equivalent overburden. EXO-200 will begin taking data in 2009, with the expected two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4 10^25 years. According to the most recent nuclear matrix element calculations, this corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV. It will also measure the two neutrino mode for the first time in 136Xe.

  3. Autoregulation of Sinorhizobium meliloti exoR gene expression.

    Science.gov (United States)

    Lu, Hai-Yang; Cheng, Hai-Ping

    2010-07-01

    The successful nitrogen-fixing symbiosis between the gram-negative soil bacterium Sinorhizobium meliloti and its leguminous plant host alfalfa (Medicago sativa) requires the bacterial exopolysaccharide succinoglycan. Succinoglycan and flagellum production, along with the ability to metabolize more than 20 different carbon sources and control the expression of a large number of S. meliloti genes, is regulated by the ExoR-ExoS/ChvI signalling pathway. The ExoR protein interacts with and suppresses the sensing activities of ExoS, the membrane-bound sensor of the ExoS/ChvI two-component regulatory system. Here we show that exoR expression is clearly upregulated in the absence of any functional ExoR protein. This upregulation was suppressed by the presence of the wild-type ExoR protein but not by a mutated ExoR protein lacking signal peptide. The levels of exoR expression could be directly modified in real time by changing the levels of total ExoR protein. The expression of exoR was also upregulated by the constitutively active sensor mutation exoS96, and blocked by two single mutations, exoS* and exoS(supA), in the ExoS sensing domain. Presence of the wild-type ExoS protein further elevated the levels of exoR expression in the absence of functional ExoR protein, and reversed the effects of exoS96, exoS* and exoS(supA) mutations. Altogether, these data suggest that ExoR protein autoregulates exoR expression through the ExoS/ChvI system, allowing S. meliloti cells to maintain the levels of exoR expression based on the amount of total ExoR protein.

  4. Orf1/SpcS Chaperones ExoS for Type Three Secretion by Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    DA-KANG SHEN; LAURIANE QUENEE; MARIETTE BONNET; LAURIANE KUHN; MADIHA DEROUAZI; DANIELE LAMOTTE; BERTRAND TOUSSAINT; BENOIT POLACK

    2008-01-01

    Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type III secretion system (TTSS)to inject effector proteins directly into the cytosol of target cells to subvert the host cell's functions.Specialized bacterial chaperones are required for effective secretion of some effectors.To identify the chaperone of ExoS,the representative effector secreted by the TTSS of P. aeruginosa,we analyzed the role of a postulated chaperone termed Orfl.Methods By allelic exchange,we constructed the mutant with the deletion of gene Orfl.Analysis of secreted and cell-associated fractions was performed by SDS-PAGE and Western blotting.Using strain expressing in trans Orfl,tagged by V5 polypeptide and histidine,protein-protein interaction Was determined by affinity resin pull-down assay in combination with MALDI-TOF. The role of Orfl in the expression of eroS was evaluated by genel reporter analysis.Results Pull-down assay showed that Orfl binds to ExoS and ExoT.Secretion profile analysis showedthat Orfl was necessary for the optimal secretion of ExoS and ExoT.However,Orfl had no effect on the expression of eroS.Conclusion Orfl is important for the secretion of ExoS probablY by mamtauung ExoS in a secretion-competent conformation.We propose to name Orfl as SpcS for "specific Pseudomonas chaperone for ExoS".

  5. Exo/Astrobiology in Europe

    Science.gov (United States)

    Brack, André; Horneck, Gerda; Wynn-Williams, David

    2001-08-01

    The question of the chemical origins of life is engraved in the European scientific patrimony as it can be traced back to the pioneer ideas of Charles Darwin, Louis Pasteur, and more recently to Alexander Oparin. During the last decades, the European community of origin of life scientists has organized seven out of the twelve International Conferences on the Origins of Life held since 1957. This community contributed also to enlarge the field of research to the study of life in extreme environments and to the search for extraterrestrial life, i.e. exobiology in its classical definition or astrobiology if one uses a more NASA-inspired terminology. The present paper aims to describe the European science background in exo/astrobiology as well as the project of a European Network of Exo/Astrobiology.

  6. Exo-endo cellulase fusion protein

    Science.gov (United States)

    Bower, Benjamin S [Palo Alto, CA; Larenas, Edmund A [Palo Alto, CA; Mitchinson, Colin [Palo Alto, CA

    2012-01-17

    The present invention relates to a heterologous exo-endo cellulase fusion construct, which encodes a fusion protein having cellulolytic activity comprising a catalytic domain derived from a fungal exo-cellobiohydrolase and a catalytic domain derived from an endoglucanase. The invention also relates to vectors and fungal host cells comprising the heterologous exo-endo cellulase fusion construct as well as methods for producing a cellulase fusion protein and enzymatic cellulase compositions.

  7. Impact of glutathione on the gene expression of exoY and exoS in Pseudomonas aeruginosa%谷胱甘肽对铜绿假单胞菌exoS和exoY基因的影响

    Institute of Scientific and Technical Information of China (English)

    张亚妮; 卫阳

    2009-01-01

    [Objective]: To study the impact of GSH (glutathione) on the gene expression of exoY and exoS in Pseudomonas aeruginosa. [Methods]: We treated P. aeruginosa with BSO (buthionine sulfoximine) and DEM (diethylmaleate) to deplete GSH, or construct the P. aeruginosa mutant containing a lacZGm disrupted gshB (glutathione synthetase) gene by homologous recombination technology. The expression of exoY and exoS was determined by measuring light production of the lux-based reporters on pMS402. [Results] :The expression of exoY and exoS decreased in the gshB mutant and P. aeruginosa treated with BSO and DEM. [Conclusion]: GSH in the P. aeruginosa can increase the expression of the genes exoY and exoS. Furthermore, this result provided possibilities to elucidate the molecular mechanisms of pathogenesis and immune response triggered by P. aeruginosa .%[目的]研究谷胱甘肽对铜绿假单胞菌exoS和exoY基因表达的影响.[方法]利用丁硫氨酸亚砜胺和马来酸二乙酯同时耗竭细胞内的谷胱甘肽,并构建包含被lacZGm破坏的谷胱甘肽合成酶基因的突变体.通过分别连有exoS和exoY基因启动子的pMS402质粒上Lux报道子发光值大小检测exoS和exoY基因表达变化情况.[结果]exoS和exoY基因的表达在用化学药品耗竭的细胞中或是在谷胱甘肽合成酶突变体中都降低.[结论]铜绿假单胞菌细胞内的谷胱甘肽可以促进exos和exoY的表达.这将为进一步研究铜绿假单胞菌的感染以及致病性机理提供一定的理论基础.

  8. Results and Status of EXO-200

    Science.gov (United States)

    Daniels, Tim; Kaufman, Lisa; EXO-200 Collaboration

    2016-09-01

    EXO-200 has provided one of the most sensitive searches for neutrinoless double-beta decay utilizing 175 kg of enriched liquid xenon in an ultra-low background time projection chamber. This detector has demonstrated excellent energy resolution and background rejection capabilities. Using the first two years of data, EXO-200 has set a limit of 1 . 1 ×1025 y at 90% C.L. on the neutrinoless double-beta decay half-life of Xe136. The experiment has experienced a brief hiatus in data taking during a temporary shutdown of its host facility: the Waste Isolation Pilot Plant. EXO-200 has resumed data taking in earnest with upgraded detector electronics. Results from the analysis of EXO-200 data and an update on the current status of EXO-200 will be presented.

  9. Result from, and status of, EXO-200

    Science.gov (United States)

    MacLellan, Ryan; EXO-200 Collaboration

    2016-03-01

    EXO-200 has provided one of the most sensitive searches for neutrinoless double-beta decay utilizing 175kg of enriched liquid xenon in an ultra-low background time projection chamber. This detector has demonstrated excellent energy resolution and background rejection capabilities. Using the first two years of data, EXO-200 has set a limit of 1 . 1 ×1025 y at 90% C.L. on the neutrinoless double-beta decay half-life of 136Xe. The experiment has experienced a brief hiatus in data taking during a temporary shutdown of its host facility: the Waste Isolation Pilot Plant. EXO-200 expects to resume data taking in earnest this fall with upgraded detector electronics. Results from the analysis of EXO-200 data and an update on the current status of EXO-200 will be presented.

  10. Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars

    Science.gov (United States)

    Howell, Steve B.; Sherry, William; Horch, Elliott; Doyle, Laurance

    2010-02-01

    The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

  11. Structural Expression of Exo-Anomeric Effect

    Science.gov (United States)

    Alonso, E. R.; Peña, Isabel; Cabezas, Carlos; Alonso, José L.

    2016-06-01

    Structural signatures for exo--anomeric effect have been extracted from the archetypal methyl--β--D--xyloside using broadband Fourier transform microwave spectroscopy combined with laser ablation. Spectrum analysis allows the determination of a set of rotational constants, which has been unequivocally attributed to conformer cc--β-4C1 g-, corresponding to the global minimum of the potential energy surface, where the aglycon residue (CH3) orientation contributes towards maximization of the exo-anomeric effect. Further analysis allowed the determination of the rs structure, based on the detection of eleven isotopologues - derived from the presence of six 13C and five 18O atoms - observed in their natural abundances. The observed glycosidic C1-O1 bond length decrease (1.38 Å) can be interpreted in terms of the exo--anomeric effect. As such, the exo--anomeric effect presents itself as one of the main driving forces controlling the shape of many biologically important oligosaccharides.

  12. Quiescent thermal emission from neutron stars in LMXBs

    CERN Document Server

    Turlione, Anabela; Pons, José A

    2013-01-01

    The quiescent thermal emission from neutron stars in low mass X-ray binaries after active periods of intense activity in x-rays (outbursts) has been monitored. The theoretical modeling of the thermal relaxation of the neutron star crust may be used to establish constraints on the crust and envelope composition and transport properties, depending on the astrophysical scenarios assumed. We perform numerical simulations of the neutron star crust thermal evolution and compare them with inferred surface temperatures for five sources: MXB 1659-29, KS 1731-260, EXO 0748-676, XTE J1701-462 and IGR J17480-2446. We also present stationary envelope models to be used as a boundary condition for the crustal cooling models. We obtain a relation between the mass accretion rate and the temperature reached at the crust-envelope interface at the end of the active phase that accounts for early observations and reduces the number of free parameters of the problem. With this relation we are also able to set constraints to the env...

  13. The New Space Age in the making: Emergence of exo-mining, exo-burials and exo-marketing

    Science.gov (United States)

    Capova, Klara Anna

    2016-10-01

    At the beginning of the 21st century we witness considerable global developments in space exploration and a new era has begun: the New Space Age. The principal symbols of that age are firstly internationalization of space activities, secondly commercial utilization of space technologies, and lastly emergence of outer space economy. This paper presents selected signposts of the New Space Age. Three cases of recent outer space enterprises: recovery of asteroid resources (exo-mining), post-cremation memorial spaceflight (exo-burials) and first extraterrestrial advert (exo-marketing), are introduced in order to emphasize the monetary and social dimension of commercial application of space technologies. To give an illustration of these trends, this paper provides a brief socioculturally minded account of three outer space undertakings that are interpreted as signposts of the new era.

  14. Burrell-Optical-Kepler Survey (BOKS): Exo-planet Search In Cygnus

    Science.gov (United States)

    Proctor, Amanda; Howell, S.; Sherry, W.; Everett, M.; von Braun, K.; Feldmeier, J.; BOKS Consortium

    2007-12-01

    We present the results of >20; continuous days of time series photometric observations of a 1.0 sq. deg field in Cygnus centered on the NASA Kepler Mission field of view. Using the Case Western Burrell Schmidt telescope located at Kitt Peak National Observatory we gathered a dataset containing light curves of roughly 30000 stars between 14exo-planet occultations. We present a summary of our photometric project including many examples of eclipsing binaries and characterization the level and content of stellar variability in this portion of the Kepler field. We will also discuss our potential exo-planet candidates.

  15. A xenon gas purity monitor for EXO

    CERN Document Server

    Dobi, A; Herrin, S; Odian, A; Prescott, C Y; Rowson, P C; Ackerman, N; Aharmin, B; Auger, M; Barbeau, P S; Barry, K; Benitez-Medina, C; Breidenbach, M; Cook, S; Counts, I; Daniels, T; DeVoe, R; Dolinski, M J; Donato, K; Fairbank, W; Farine, J; Giroux, G; Gornea, R; Graham, K; Gratta, G; Green, M; Hagemann, C; Hall, K; Hallman, D; Hargrove, C; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Lacey, J; Leonard, D S; LePort, F; Mackay, D; MacLellan, R; Mong, B; Diez, M Montero; Muller, A R; Neilson, R; Niner, E; O'Sullivan, K; Piepke, A; Pocar, A; Pushkin, K; Rollin, E; Sinclair, D; Slutsky, S; Stekhanov, V; Twelker, K; Voskanian, N; Vuilleumier, J -L; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2011-01-01

    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

  16. EXO-200 results and cosmogenic backgrounds

    Science.gov (United States)

    Belov, V. A.; EXO-200 collaboration

    2017-01-01

    Status update and recent results from the double beta decay search experiment EXO-200 are presented. Detector is a liquid xenon TPC with charge and light readout located underground in low-background laboratory at 1600 m.w.e. depth. It contains 175 kg of xenon with 80.6% abundance of 136Xe, which acts as both the decaying nucleus and detection medium. Detector showed good performance and achieved remarkable results. The detector has demonstrated excellent energy resolution and background rejection capabilities and has set a lower limit on the 0νββ-decay half-life of 1.1 × 1025 years at 90% C.L. in early 2014. The EXO-200 collaboration has since published several papers on experimental backgrounds and searches for rare or exotic processes. After a two-year data interruption, EXO-200 is now back online with significant hardware improvements, including a radon reduction air system and a front end electronics upgrade for better energy resolution.

  17. Possible regular phenomena in EXO 2030+375

    CERN Document Server

    Laplace, Eva; Moritani, Yuki; Nakajima, Motoki; Takagi, Toshihiro; Makishima, Kazuo; Santangelo, Andrea

    2016-01-01

    In the last 10 years, since its last giant outburst in 2006, regular X-ray outbursts (type I) were detected every periastron passage in the Be X-ray binary EXO 2030+375. Recently, however, it was reported that the source started to show a peculiar behavior: its X-ray flux decreased significantly and type I outbursts were missed in several cases. At the same time, the spin frequency of the neutron star, which had been increasing steadily since the end of the 2006 giant outburst, reached a plateau. Very recent observations indicate that the source is now starting to spin down. These observed phenomena have a striking similarity with those which took place 20 years ago, just before the source displayed a sudden orbital phase shift of the outburst peak (1995). This historical event occurred at the time exactly between the two giant outbursts (1985 and 2006). These phenomena suggest the system to have an underlying periodicity of 10.5 years between orbital phase shifts and/or giant outbursts. The suggested periodi...

  18. Measuring Neutron Star Mass and Radius with Three Mass-Radius Relations

    CERN Document Server

    Zhang, C M; Kojima, Y; Chang, H K; Xu, R X; Li, X D; Zhang, B; Kiziltan, B

    2006-01-01

    We propose to determine the mass and the radius of a neutron star (NS) using three measurable mass-radius relationships, namely the ``apparent'' radius inferred from neutron star thermal emission, the gravitational redshift inferred from the absorption lines, as well as the averaged stellar mass density inferred from the orbital Keplerian frequency derived from the kilohertz quasi periodic oscillation (kHz QPO) data. We apply the method to constrain the NS mass and the radius of the X-ray sources, 1E 1207.4-5209, Aql X-1 and EXO 0748-676.

  19. The ExoMars 2016 Mission

    Science.gov (United States)

    Svedhem, Håkan; Vago, Jorge; de Groot, Rolf; McCoy, Don

    2016-04-01

    ExoMars is a joint programme of the European Space Agency (ESA) and Roscosmos, Russia. It consists of the ExoMars 2016 mission with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2018 mission, which carries a lander and a rover. The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector to search for subsurface hydrogen (as proxy for water ice and hydrated minerals). The mass of the TGO is 3700 kg, including fuel. The EDM, with a mass of 600 kg, is mounted on top of the TGO as seen in its launch configuration. The EDM is carried to Mars by the TGO and is separated three days before arrival at Mars. In addition to demonstrating the landing capability two scientific investigations are included with the EDM. The AMELIA investigation aims at characterising the Martian atmosphere during the entry and descent using technical and engineering sensors of the EDM, and the DREAMS suite of sensors that will characterise the environment of the landing site for a few days after the landing. ESA provides the TGO spacecraft and the Schiaparelli Lander demonstrator, ESA member states provide two of the TGO instruments and Roscosmos provides the launcher and the other two TGO instruments. After the arrival of the ExoMars 2018 mission at the surface of Mars, the TGO will handle all communications between the Earth and the Rover. The communication between TGO and the rover/lander is done through a UHF communications system, a contribution from NASA. The 2016 mission will be launched by a Russian Proton rocket from Baikonur in March 2016 (launch window 14-25 March) and will arrive at Mars on 19 October. This presentation will cover a description of the 2016 mission, including the spacecraft

  20. Exo-celiac liver in Glyptosternum maculatum

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A unique structure in the fish of Glyptosternum maculatum (Regan) (Siluriformes: Sisoridae) is reported. It was identified as a part of the liver named "exo-celiac liver". This new organ is located between skin and muscle and connected with the celiac liver by a funiform tissue, "joint belt". It has similar histological features and isozyme electrophoretogramic bands of lactate dehydrogenase, esterase, malate dehydrogenase and alcohol dehydrogenase as in the celiac liver. This unique organ has biological research value and could serve as an important tool for studying organogenesis and evolution.

  1. The exo-metabolome in filamentous fungi

    DEFF Research Database (Denmark)

    Thrane, Ulf; Andersen, Birgitte; Frisvad, Jens Christian

    2007-01-01

    Filamentous fungi are a diverse group of eukaryotic microorganisms that have a significant impact on human life as spoilers of food and feed by degradation and toxin production. They are also most useful as a source of bulk and fine chemicals and pharmaceuticals. This chapter focuses on the exo......-metabolome in filamentous fungi, which comprises more than 30,000 known secondary metabolites. Profiles of this diverse range of secondary metabolites have, for more than 25 years, been central in development of fungal systematics, taxonomy, and ecology, today integrated in a multidisciplinary and polyphasic approach...

  2. ExoMars 2016 arrives at Mars

    Science.gov (United States)

    Svedhem, Hakan; Vago, Jorge L.; ExoMars Team

    2016-10-01

    The Trace Gas Orbiter (TGO) and the Schiaparelli Entry, descent and landing Demonstrator Model (EDM) will arrive at Mars on 19 October 2016. The TGO and the EDM are part of the first step of the ExoMars Programme. They will be followed by a Rover and a long lived Surface Platform to be launched in 2020.The EDM is attached to the TGO for the full duration of the cruise to Mars and will be separated three days before arrival at Mars. After separation the TGO will perform a deflection manoeuvre and, on 19 October (during the EDM landing), enter into a highly elliptical near equatorial orbit. TGO will remain in this parking orbit until January 2017, when the orbital plane inclination will be changed to 74 degrees and aerobraking to the final 400 km near circular orbit will start. The final operational orbit is expected to be reached at the end of 2017.The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector for search of subsurface hydrogen. The mass of the TGO is 3700 kg, including fuel. The EDM, with a mass of 600 kg, is mounted on top of the TGO as seen in its launch configuration. The main objective of the EDM is to demonstrate the capability of performing a safe entry, descent and landing on the surface, but it does carry a descent camera and a small battery powered meteorological package that may operate for a few days on the surface.The ExoMars programme is a joint activity by the European Space Agency(ESA) and ROSCOSMOS, Russia. ESA is providing the TGO spacecraft and Schiaparelli (EDM) and two of the TGO instruments and ROSCOSMOS is providing the launcher and the other two TGO instruments. After the arrival of the ExoMars 2020 mission at the surface of Mars, the TGO will handle the communication between the Earth and the Rover and

  3. Glancing through the accretion column of EXO 2030+375

    Science.gov (United States)

    Ferrigno, Carlo; Pjanka, Patryk; Bozzo, Enrico; Klochkov, Dmitry; Ducci, Lorenzo; Zdziarski, Andrzej A.

    2016-09-01

    Context. The current generation of X-ray instruments progressively reveals more and more details about the complex magnetic field topology and the geometry of the accretion flows in highly magnetized accretion-powered pulsars. Aims: We took advantage of the large collecting area and good timing capabilities of the EPIC cameras onboard XMM-Newton to investigate the accretion geometry onto the magnetized neutron star hosted in the high-mass X-ray binary EXO 2030+375 during the rise of a source type I outburst in 2014. Methods: We carried out a timing and spectral analysis of the XMM-Newton observation as a function of the neutron star spin phase. We used a phenomenological spectral continuum model comprising the required fluorescence emission lines. Two neutral absorption components are present: one covering the source fully, one only partially. The same analysis was also carried out on two Suzaku observations of the source performed during outbursts in 2007 and 2012, to search for possible spectral variations at different luminosities. Results: The XMM-Newton data caught the source at an X-ray luminosity of 2 × 1036 erg s-1 and revealed a narrow dip-like feature in its pulse profile that was never reported before. The width of this feature corresponds to about one hundredth of the neutron star spin period. Based on the results of the phase-resolved spectral analysis we suggest that this feature can be ascribed to the self-obscuration of the accretion stream passing in front of the observer line of sight. We inferred from the Suzaku observation carried out in 2007 that the self-obscuration of the accretion stream might produce a significantly wider feature in the neutron star pulsed profile at higher luminosities (≳2 × 1037 erg s-1). Conclusions: This discovery allowed us to derive additional constraints on the physical properties of the accretion flow in this object at relatively small distances from the neutron star surface. The narrow dip-like feature in the

  4. Novel endo- to exo-isomerization of dicyclopentadiene

    Institute of Scientific and Technical Information of China (English)

    Xiang Wen Zhang; Kai Jiang; Qiang Jiang; Ji Jun Zou; Li Wang; Zhen Tao Mi

    2007-01-01

    Endo-dicyclopentadiene was isomerized to exo-isomer by thermal treatment at evaluated temperature and pressure.The reaction temperature and pressure are key factors for this novel isomerization.This result may have great potential for practical application.

  5. ExoData: A Python package to handle large exoplanet catalogue data

    Science.gov (United States)

    Varley, Ryan

    2016-10-01

    Exoplanet science often involves using the system parameters of real exoplanets for tasks such as simulations, fitting routines, and target selection for proposals. Several exoplanet catalogues are already well established but often lack a version history and code friendly interfaces. Software that bridges the barrier between the catalogues and code enables users to improve the specific repeatability of results by facilitating the retrieval of exact system parameters used in articles results along with unifying the equations and software used. As exoplanet science moves towards large data, gone are the days where researchers can recall the current population from memory. An interface able to query the population now becomes invaluable for target selection and population analysis. ExoData is a Python interface and exploratory analysis tool for the Open Exoplanet Catalogue. It allows the loading of exoplanet systems into Python as objects (Planet, Star, Binary, etc.) from which common orbital and system equations can be calculated and measured parameters retrieved. This allows researchers to use tested code of the common equations they require (with units) and provides a large science input catalogue of planets for easy plotting and use in research. Advanced querying of targets is possible using the database and Python programming language. ExoData is also able to parse spectral types and fill in missing parameters according to programmable specifications and equations. Examples of use cases are integration of equations into data reduction pipelines, selecting planets for observing proposals and as an input catalogue to large scale simulation and analysis of planets.

  6. The GAP Portion of Pseudomonas Aeruginosa Type III Secreted Toxin ExoS Upregulates Total and Surface Levels of Wild Type CFTR

    Directory of Open Access Journals (Sweden)

    Deepali N. Tukaye

    2013-02-01

    Full Text Available Background: Pseudomonas aeruginosa (PA infections account for a large percentage of fatal hospital acquired pneumonias. One of the PA Type III secreted toxin (TTST ExoS, a bifunctional protein with N-terminal GTPase activating protein (GAP and C-terminal ADP rybosyl transferase (ADPRT activities, significantly contributes to PA virulence by targeting small molecular weight G-proteins (SMWGP. In this study, we have looked at one of the mechanisms by which the GAP portion of ExoS (ExoS-GAP mediates cellular toxicity. Methods: The effects of ExoS-GAP on CFTR trafficking were studied in CFBE41o- Kir 2.2 and MDCK cell lines stably expressing CFTR using a transient transfection system. Results: Transient transfection of ExoS-GAP increased the total and surface protein levels of mature wild type CFTR in epithelial cells stably expressing wild type (WT CFTR. The effect of ExoS-GAP was specific to CFTR in bronchial epithelial cells since it did not affect the total protein levels of Na+/K+ATPase, another membrane protein. A point mutation in the ExoS GAP domain (R146K, known to disrupt its catalytic GAP activity, abolished the effect of ExoS-GAP on WT CFTR. Lysosomal inhibition studies with Bafilomycin A1 indicate that ExoS-GAP decreased lysosomal degradation of the mature WT CFTR with concomitant increase in the total levels of mature WT CFTR. However, ExoS-GAP did not increase the total protein levels of ∆F508CFTR. Conclusion: The GAP portion of the PA TTST ExoS increases the total and surface levels of wild type CFTR in vitro mammalian cell system. The effect of ExoS-GAP on WT CFTR total protein levels provides new insight into understanding the virulent pathophysiology of PA infections.

  7. Characterization of Large Area APDs for the EXO-200 Detector

    Energy Technology Data Exchange (ETDEWEB)

    Neilson, R.; LePort, F.; Pocar, A.; /Stanford U., Phys. Dept.; Kumar, K.; /Massachusetts U., Amherst; Odian, A.; Prescott, C.Y.; /SLAC; Tenev, V.; /Stanford U., Phys. Dept.; Ackerman, N.; /SLAC; Akimov, D.; /Moscow, ITEP; Auger, M.; /Bern U., LHEP; Benitez-Medina, C.; /Colorado State U.; Breidenbach, M.; /SLAC; Burenkov, A.; /Moscow, ITEP; Conley, R.; /SLAC; Cook, S.; /Colorado State U.; deVoe, R.; Dolinski, M.J.; /Stanford U., Phys. Dept.; Fairbank, W., Jr.; /Colorado State U.; Farine, J.; /Laurentian U.; Fierlinger, P.; Flatt, B.; /Stanford U., Phys. Dept. /Bern U., LHEP /Stanford U., Phys. Dept. /Maryland U. /Colorado State U. /Laurentian U. /Carleton U. /SLAC /Maryland U. /Moscow, ITEP /Alabama U. /SLAC /Colorado State U. /Stanford U., Phys. Dept. /Alabama U. /Stanford U., Phys. Dept. /Alabama U. /SLAC /Carleton U. /SLAC /Maryland U. /Moscow, ITEP /Carleton U. /Stanford U., Phys. Dept. /Bern U., LHEP /SLAC /Laurentian U. /SLAC /Maryland U.

    2011-12-02

    EXO-200 uses 468 large area avalanche photodiodes (LAAPDs) for detection of scintillation light in an ultra-low-background liquid xenon (LXe) detector. We describe initial measurements of dark noise, gain and response to xenon scintillation light of LAAPDs at temperatures from room temperature to 169 K - the temperature of liquid xenon. We also describe the individual characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.

  8. Characterization of large area APDs for the EXO-200 detector

    CERN Document Server

    Neilson, R; Pocar, A; Kumar, K; Odian, A; Prescott, C Y; Tenev, V; Ackerman, N; Akimov, D; Auger, M; Benitez-Medina, C; Breidenbach, M; Burenkov, A; Conley, R; Cook, S; deVoe, R; Dolinski, M J; Fairbank, W; Farine, J; Fierlinger, P; Flatt, B; Gornea, R; Gratta, G; Green, M; Hall, C; Hall, K; Hallman, D; Hargrove, C; Herrin, S; Hodgson, J; Kaufman, L J; Kovalenko, A; Leonard, D S; Mackay, D; Mong, B; Diez, M Montero; Niner, E; O'Sullivan, K; Piepke, A; Rowson, P C; Sinclair, D; Skarpaas, K; Slutsky, S; Stekhanov, V; Strickland, V; Twelker, K; Vuilleumier, J -L; Wamba, K; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2009-01-01

    EXO-200 uses 468 large area avalanche photodiodes (LAAPDs) for detection of scintillation light in an ultra-low-background liquid xenon (LXe) detector. We describe initial measurements of dark noise, gain and response to xenon scintillation light of LAAPDs at temperatures from room temperature to 169K - the temperature of liquid xenon. We also describe the individual characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.

  9. ExoData: A python package to handle large exoplanet catalogue data

    CERN Document Server

    Varley, Ryan

    2015-01-01

    Exoplanet science often involves using the system parameters of real exoplanets for tasks such as simulations, fitting routines, and target selection for proposals. Software that bridges the barrier between the catalogues and code enables users to improve the specific repeatability of results by facilitating the retrieval of exact system parameters used in an articles results along with unifying the equations and software used. As exoplanet science moves towards large data, gone are the days where researchers can recall the current population from memory. An interface able to query the population now becomes invaluable for target selection and population analysis. ExoData is a python interface and exploratory analysis tool for the Open Exoplanet Catalogue. It allows the loading of exoplanet systems into python as objects (Planet, Star, Binary etc) from which common orbital and system equations can be calculated and measured parameters retrieved. This allows researchers to use tested code of the common equatio...

  10. ExoMars: Overview of scientific programme

    Science.gov (United States)

    Rodionov, Daniel; Witasse, Olivier; Vago, Jorge L.

    The ExoMars Programme is a joint project between the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos). The project consists of two missions with launches in 2016 and 2018. The scientific objectives of ExoMars are: begin{itemize} To search for signs of past and present life on Mars. To investigate the water/geochemical environment as a function of depth in the shallow subsurface. To study Martian atmospheric trace gases and their sources. To characterize the surface environment. The 2016 mission will be launched (January 2016) on a Proton rocket. It includes the Trace Gas Orbiter (TGO) and an Entry, descent and landing Demonstrator Module (EDM), both contributed by ESA. The TGO will carry European and Russian scientific instruments for remote observations, while the EDM will have a European payload for in-situ measurements during descent and on the Martian surface. The TGO scientific payload includes:begin{itemize} NOMAD. Suite of 2 Infrared (IR) and 1 Ultraviolet (UV) spectrometer. ACS. Suite of 2 IR echelle-spectrometers (near and middle IR) and 1 Fourier spectrometer. FREND. Neutron spectrometer with a collimation module. CaSSIS. High-resolution camera. The EDM payload includes a set of accelerometers and heat shield sensors (AMELIA), to study the Martian atmosphere and obtain images throughout the EDM’s descent, and an environmental station (DREAMS), to conduct a series of short meteorological observations at the EDM’s landing location. The 2018 mission will land a Rover, provided by ESA, making use of a Descent Module (DM) contributed by Roscosmos. The mission will be launched on a Proton rocket (May 2018). The ExoMars rover will have a nominal lifetime of approximately 6 months. During this period, it will ensure a regional mobility of several kilometres, relying on solar array electrical power. The rover’s Pasteur payload will produce self-consistent sets of measurements capable to provide reliable evidence, for or against

  11. EXOS research on force-reflecting controllers

    Science.gov (United States)

    Eberman, Brian S.; An, Bin

    1993-03-01

    EXOS has developed two state of the art prototype master controllers for controlling robot hands and manipulators under the Small Business Innovation Research (SBIR) program with NASA. One such device is a two degree-of-freedom Sensing and Force Reflecting Exoskeleton (SAFiRE) worn on the operator's hand. The device measures the movement of the index finger and reflects the interaction forces between the slave robot and the environment to the human finger. The second device is a position sensing Exoskeleton ArmMaster (EAM) worn by a human operator. The device simultaneously tracks the motions of the operator's three DOF shoulder and two DOF elbow. Both of these devices are currently used to control robots at NASA. We are currently developing a full fingered SAFiRE and a position sensing and force reflecting EAM under two second phase SBIR grants with NASA. This paper will include discussions of: (1) the design of the current prototypes, (2) kinematics of the EAM and force control of the SAFiRE, (3) design issues that must be addressed in developing more advanced versions, and (4) our progress to date in addressing these issues.

  12. THE ENDO-EXO-FEMORAL PROSTHESIS

    Directory of Open Access Journals (Sweden)

    H. Aschoff

    2011-01-01

    Full Text Available Patients with above knee amputation (AKA face many challenges to mobility including difficulty with socket fit and fatigue due to high energy consumption. The aim of the Endo-Exo-Femur Prosthesis (EEFP is to avoid problems at the interface between the sleeve of the socket-prosthesis and the soft tissue coat of the femur stump which often impedes an inconspicuous and harmonic gait. In 1999 we began using a transcutaneous, press-fit distal femoral intramedullary device whose most distal external aspect serves as a hard point for AKA prosthesis attachment. The bone guided prosthesis enables an advanced gait via osseoperception and leads to a decreased oxygen consumption of the patient. Thirty two patients underwent the procedure between 1999 and 2008. Their indication for surgery was persistent AKA prosthesis difficulties with a history of AKA for trauma. The paper presents the patient data regarding the design of the implant, the operative procedure, patient satisfaction, gait analysis and oxygen consumption.

  13. ExoMars Entry, Descent, and Landing Science

    Science.gov (United States)

    Karatekin, Özgür; Forget, Francois; Withers, Paul; Colombatti, Giacomo; Aboudan, Alessio; Lewis, Stephen; Ferri, Francesca; Van Hove, Bart; Gerbal, Nicolas

    2016-07-01

    Schiaparelli, the Entry Demonstrator Module (EDM) of the ESA ExoMars Program will to land on Mars on 19th October 2016. The ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA) team seeks to exploit the Entry Descent and Landing (EDL) engineering measurements of Schiaparelli for scientific investigations of Mars' atmosphere and surface. ExoMars offers a rare opportunity to perform an in situ investigation of the martian environment over a wide altitude range. There has been only 7 successfully landing on the surface of Mars, from the Viking probes in the 1970's to the Mars Science Laboratory (MSL) in 2012. ExoMars EDM is equipped with an instrumented heat shield like MSL. These novel flight sensors complement conventional accelerometer and gyroscope instrumentation, and provide additional information to reconstruct atmospheric conditions with. This abstract outlines general atmospheric reconstruction methodology using complementary set of sensors and in particular the use of surface pressure and radio data. In addition, we discuss the lessons learned from previous EDL and the plans for ExoMars AMELIA data analysis.

  14. Interacting binaries

    CERN Document Server

    Shore, S N; van den Heuvel, EPJ

    1994-01-01

    This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

  15. EXO70C2 is a key regulatory factor for optimal tip growth of pollen

    KAUST Repository

    Synek, Lukas

    2017-03-30

    The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.

  16. Proofreading genotyping assays mediated by high fidelity exo+ DNA polymerases.

    Science.gov (United States)

    Zhang, Jia; Li, Kai; Pardinas, Jose R; Sommer, Steve S; Yao, Kai-Tai

    2005-02-01

    DNA polymerases with 3'-5' proofreading function mediate high fidelity DNA replication but their application for mutation detection was almost completely neglected before 1998. The obstacle facing the use of exo(+) polymerases for mutation detection could be overcome by primer-3'-termini modification, which has been tested using allele-specific primers with 3' labeling, 3' exonuclease-resistance and 3' dehydroxylation modifications. Accordingly, three new types of single nucleotide polymorphism (SNP) assays have been developed to carry out genome-wide genotyping making use of the fidelity advantage of exo(+) polymerases. Such SNP assays might also provide a novel approach for re-sequencing and de novo sequencing. These new mutation detection assays are widely adaptable to a variety of platforms, including real-time PCR, multi-well plate and microarray technologies. Application of exo(+) polymerases to genetic analysis could accelerate the pace of personalized medicine.

  17. ExoMars 2018 Landing Site Selection Process

    Science.gov (United States)

    Vago, Jorge L.; Kminek, Gerhard; Rodionov, Daniel

    The ExoMars 2018 mission will include two science elements: a Rover and a Surface Platform. The ExoMars Rover will carry a comprehensive suite of instruments dedicated to geology and exobiology research named after Louis Pasteur. The Rover will be able to travel several kilometres searching for traces of past and present signs of life. It will do this by collecting and analysing samples from outcrops, and from the subsurface—down to 2-m depth. The very powerful combination of mobility with the ability to access locations where organic molecules can be well preserved is unique to this mission. After the Rover will have egressed, the ExoMars Surface Platform will begin its science mission to study the surface environment at the landing location. This talk will describe the landing site selection process and introduce the scientific, planetary protection, and engineering requirements that candidate landing sites must comply with in order to be considered for the mission.

  18. Evaluation of Xylem EXO water-quality sondes and sensors

    Science.gov (United States)

    Snazelle, Teri T.

    2015-01-01

    Two models of multiparameter sondes manufactured by Xylem, parent company of Yellow Springs Incorporated (YSI)—EXO1 and EXO2—equipped with EXO conductivity/temperature (C/T), pH, dissolved oxygen (DO), and turbidity sensors, were evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility. The sondes and sensors were evaluated in two phases for compliance with the manufacturer’s specifications and the USGS acceptance criteria for continuous water-quality monitors. Phase one tested the accuracy of the water-quality sondes equipped: (a) with a C/T, pH, DO, and turbidity sensor by comparing the EXO sensors’ measured values to those of an equivalently configured YSI 6920 V2-2 sensor, and (b) with multiple sensors of the same parameter type (such as three pH sensors and a C/T sensor) on a single sonde at room temperature and at an extended temperature range. In addition to accuracy, the communication protocols and the manufacturing specifications for range of detection and operating temperature were also tested during this phase. Phase two evaluated the sondes’ performance in a surface-water environment by deploying an EXO1 and an EXO2 equipped with pH, C/T, DO, and turbidity sensors at USGS site 02492620 located at East Pearl River near Bay Saint Louis, Mississippi. The EXO sondes’ temperature deviations from a certified YSI 4600 digital thermometer were within the ±0.2 degree Celsius (°C) USGS criteria, but were greater than the ±0.01 °C manufacturing specification. The conductivity sensors met the ±3 percent USGS criteria for specific conductance greater than 100 microsiemens per centimeter. The sensors met the more stringent ±0.5 percent manufacturing specification only at room temperature in the 250 microsiemens per centimeter (µS/cm) standard. The manufacturing and USGS criteria (±0.2 pH unit) were met in pH standards 4, 9.2, 10, and 12.45, but were not met in pH 1.68 standard. The DO sensors met both the ±0.3 milligram

  19. Exo-atmospheric target discrimination using probabilistic neural network

    Institute of Scientific and Technical Information of China (English)

    Jianlai Wang; Chunling Yang

    2011-01-01

    Exo-atmospheric targets are especially difficult to distinguish using currently available techniques,because all target parts follow the same spatial trajectory.The feasibility of distinguishing multiple type compo-nents of exo-atmospheric targets is demonstrated by applying the probabilistic neural network.Differences in thermal behavior and time-varying signals of space-objects are analyzed during the selection of features used as inputs of the neural network.A novel multi-colorimetric technology is introduced to measure precisely the temporal evolutional characteristics of temperature and emissivity-area products.To test the effectiveness of the recognition algorithm,the results obtained from a set of synthetic multispectral data set are presented and discussed.These results indicate that the discrimination algorithm can obtain a remarkable success rate.

  20. 2-exo,5-endo,8,8,10-Pentachlorobornane

    Directory of Open Access Journals (Sweden)

    Vladimir Nikiforov

    2008-04-01

    Full Text Available The title compound, C10H13Cl5, is a polychlorinated monoterpene and a Toxaphene congener. This compound is also the only pentachlorinated derivative of camphene formed via ionic chlorination. Previously, the title compound was thought to be 2-exo,5-endo,9,9,10-pentachlorobornane, but X-ray structural analysis showed it to have a different structure and rather to be 2-exo,5-endo,8,8,10-pentachlorobornane. The title compound shows static disorder and almost half the molecule was divided in two partitions with an occupancy ratio of 0.575 (major to 0.425 (minor. The repulsive close contacts of Cl atoms could possibly be the cause for this disorder.

  1. Continuing the Operation of EXO-200 at WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Gratta, Giorgio [Stanford Univ., CA (United States)

    2016-02-24

    This grant supported, in part, the operations of the EXO-200 double beta decay experiment at the Waste Isolation Pilot Plant (WIPP) for the period May 1, 2013 to Sept 30, 2015. In this period EXO-200 completed its first phase of data taking, although its operation was disrupted in Feb 2014 by the accidents at WIPP (unrelated to the experiment). The primary goal of the experiment is to search for the very rate (and to date not observed) neutrino-less double beta decay. Such decay, if observed, would shed the light of the quantum-mechanical structure of neutrinos, and the origins of elementary particle masses. Another goal of the detector is to serve as prototype of a larger neutrino-less double beta decay experiment, currently being considered by DOE-OS.

  2. Direct thermal imaging of circumstellar discs and exo-planets

    Science.gov (United States)

    Pantin, Eric; Siebenmorgen, Ralf; Cavarroc, Celine; Sterzik, Michael F.

    2008-07-01

    The phase A study of a mid infrared imager and spectrograph for the European Extremely Large Telescope (E-ELT), called METIS, was endorsed in May 2008. Two key science drivers of METIS are: a) direct thermal imaging of exo-planets and b) characterization of circumstellar discs from the early proto-planetary to the late debris phase. Observations in the 10μm atmospheric window (N band) require a contrast ratio between stellar light and emitted photons from the exo-planet or the disc of ~ 105. At shorter wavelengths the contrast between star and reflected light from the planet-disc system exceeds >~ 107 posing technical challenges. By means of end-to-end detailed simulations we demonstrate that the superb spatial resolution of a 42m telescope in combination with stellar light rejection methods such as coronagraphic or differential imaging will allow detections at 10μm for a solar type system down to a star-planet separation of 0.1" and a mass limit for irradiated planets of 1 Jupiter (MJ) mass. In case of self-luminous planets observations are possible further out e.g. at the separation limit of JWST of ~ 0.7", METIS will detect planets >~5MJ. This allows to derive a census of all such exo-planets by means of thermal imaging in a volume limited sample of up to 6pc. In addition, METIS will provide the possibility to study the chemical composition of atmospheres of exo-planets using spectroscopy at moderate spectral resolution (λ/Δλ ~ 100) for the brightest targets. Based on detailed performance and sensitivity estimates, we demonstrate that a mid-infrared instrument on an ELT is perfectly suited to observe gravitationally created structures such as gaps in proto- and post- planetary discs, in a complementary way to space missions (e.g. JWST, SOFIA) and ALMA which can only probe the cold dust emission further out.

  3. Evidence Contrary to the Existing Exo-Planet Migration Concept

    CERN Document Server

    Herndon, J M

    2006-01-01

    Exo-planet migration is assumed to have occurred to explain close-to-star gas giant exo-planets within the context of the so-called standard model of solar system formation, rather than giving cause to question the validity of that particular model. I present evidence against the concept of planet migration, evidence that is historical, interdisciplinary, and model-independent. First, I demonstrate a flaw in the standard model of solar system formation that would lead to the contradiction of terrestrial planets having insufficiently massive cores. Then, I discuss the evidence that points to the Earth previously having been a Jupiter-like close-to-Sun gas giant and the consequences that arise there from. Observations of close-to-star gas giant exo-planets orbiting stars other than our own Sun, rather than being evidence for planet migration, I submit, are evidence for differing degrees of violence associated with the thermonuclear ignition of their particular stars. As observational resolution improves, one mi...

  4. The next generation neutrinoless double-beta decay experiment nEXO

    Science.gov (United States)

    MacLellan, Ryan; nEXO Collaboration

    2017-01-01

    The nEXO Collaboration is actively engaged in R&D towards a very large detector for neutrinoless double beta decay of 136Xe. The nEXO detector is rooted in the current EXO-200 program, which has reached a sensitivity for the half-life of the decay of 1 . 9 ×1025 y with an exposure of 99.8 kg-y. The baseline nEXO design assumes 5 tonnes of liquid xenon, enriched in the mass 136 isotope, within a large monolithic time projection chamber. The initial goal for nEXO is a neutrinoless double-beta decay half-life sensitivity of 1 ×1028 y, covering the inverted neutrino mass hierarchy with 5 years of data. We present the conceptual nEXO detector design, the current status of R&D efforts, and the physics case for the experiment.

  5. Systematic Study of Trace Radioactive Impurities in Candidate Construction Materials for EXO-200

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, D.S.; Grinberg, P.; Weber, P.; Baussan, E.; Djurcic, Z.; Keefer, G.; Piepke, A.; Pocar, A.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; Akimov, D.; Bellerive, A.; Bowcock, M.; Breidenbach, M.; Burenkov, A.; Conley, R.; Craddock, W.; Danilov, M.; DeVoe, R.; Dixit, M.; Dolgolenko, A.; /Alabama U. /NRC-INMS /Neuchatel U. /Stanford U., Phys. Dept. /SLAC /Colorado State U. /Laurentian U. /Maryland U. /UC, Irvine

    2007-10-24

    The Enriched Xenon Observatory (EXO) will search for double beta decays of 136Xe. We report the results of a systematic study of trace concentrations of radioactive impurities in a wide range of raw materials and finished parts considered for use in the construction of EXO-200, the first stage of the EXO experimental program. Analysis techniques employed, and described here, include direct gamma counting, alpha counting, neutron activation analysis, and high-sensitivity mass spectrometry.

  6. Production, Purification of Exo-Polygalacturonase from Soil Isolate Paecilomyces variotii NFCCI 1769 and Its Application

    OpenAIRE

    Patil, Nitinkumar P.; Patil, Kanchankumar P.; Bhushan L. Chaudhari; Chincholkar, Sudhir B.

    2011-01-01

    The aim of the present study was to produce exo-polygalacturonase from potent soil isolate by submerged fermentation and its application for fruit juice treatment. Pectinase producing strains were selectively isolated from pectin industry waste. A selected isolate C2 was found to produce significant amount of exo-polygalacturonase. The isolate was identified as Paecilomyces variotii on the basis of morphological characteristics and 18S rRNA gene sequence analysis. The exo-polygalacturonase pr...

  7. Preparations for ExoMars: Learning Lessons from Curiosity

    Science.gov (United States)

    Edwards, Peter Henry; Hutchinson, Ian; Morgan, Sally; McHugh, Melissa; Malherbe, Cedric; Lerman, Hannah; INGLEY, Richard

    2016-10-01

    In 2020, the European Space Agency will launch its first Mars rover mission, ExoMars. The rover will use a drill to obtain samples from up to 2m below the Martian surface that will then be analysed using a variety of analytical instruments, including the Raman Laser Spectrometer (RLS), which will be the first Raman spectrometer to be used on a planetary mission.To prepare for ExoMars RLS operations, we report on a series of experiments that have been performed in order to investigate the response of a representative Raman instrument to a number of analogue samples (selected based on the types of material known to be important, following investigations performed by NASA's Mars Science Laboratory, MSL, on the Curiosity rover). Raman spectroscopy will provide molecular and mineralogical information about the samples obtained from the drill cores on ExoMars. MSL acquires similar information using the CheMin XRD instrument which analyses samples acquired from drill holes several centimetres deep. Like Raman spectroscopy, XRD also provides information on the mineralogical makeup of the analysed samples.The samples in our study were selected based on CheMin data obtained from drill sites at Yellowknife Bay, one of the first locations visited by Curiosity (supplemented with additional fine scale elemental information obtained with the ChemCam LIBS laser instrument). Once selected (or produced), the samples were characterised using standard laboratory XRD and XRF instruments (in order to compare with the data obtained by CheMin) and a standard, laboratory based LIBS system (in order to compare with the ChemCam data). This characterisation provides confirmation that the analogue samples are representative of the materials likely to be encountered on Mars by the ExoMars rover.A representative, miniaturised Raman spectrometer was used to analyse the samples, using acquisition strategies and operating modes similar to those expected for the ExoMars instrument. The type of

  8. A superburst candidate in EXO 1745--248 as a challenge to thermonuclear ignition models

    CERN Document Server

    Altamirano, D; Cumming, A; Sivakoff, G R; Heinke, C O; Wijnands, R; Degenaar, N; Homan, J; Pooley, D

    2012-01-01

    We report on Chandra, RXTE, Swift/BAT and MAXI observations of a ~1 day X-ray flare and subsequent outburst of a transient X-ray source observed in October-November 2011 in the globular cluster Terzan 5. We show that the source is the same as the transient that was active in 2000, i.e., the neutron star low-mass X-ray binary EXO 1745-248. For the X-ray flare we estimate a 6-11 hr exponential decay time and a radiated energy of 2-9 x 10^42 erg. These properties, together with strong evidence of decreasing blackbody temperature during the flare decay, are fully consistent with what is expected for a thermonuclear superburst. We use the most recent superburst models and estimate an ignition column depth of ~10^12 g cm^-2 and an energy release between 0.1-2 x 10^18 erg g^-1, also consistent with expected superburst values. We conclude therefore that the flare was most probably a superburst. We discuss our results in the context of theoretical models and find that even when assuming a few days of low level accreti...

  9. Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes.

    Science.gov (United States)

    Schaetzlein, Sonja; Chahwan, Richard; Avdievich, Elena; Roa, Sergio; Wei, Kaichun; Eoff, Robert L; Sellers, Rani S; Clark, Alan B; Kunkel, Thomas A; Scharff, Matthew D; Edelmann, Winfried

    2013-07-02

    Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1(EK)) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1(null)) mouse. In contrast to Exo1(null/null) mice, Exo1(EK/EK) mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1(null) mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.

  10. Relativistic model of neutron stars in X-ray binary

    Science.gov (United States)

    Kalam, Mehedi; Hossein, Sk Monowar; Islam, Rabiul; Molla, Sajahan

    2017-02-01

    In this paper, we study the inner structure of some neutron stars from theoretical as well as observational points of view. We calculate the probable radii, compactness (u) and surface redshift (Zs) of five neutron stars (X-ray binaries) namely 4U 1538-52, LMC X-4, 4U 1820-30, 4U 1608-52, EXO 1745-248. Here, we propose a stiff equation of state (EoS) of matter distribution which relates pressure with matter density. Finally, we check the stability of such kind of theoretical structure.

  11. Compact Stars in low-mass X-ray binaries

    OpenAIRE

    Hossein, Sk. Monowar; Molla, Sajahan; Jafry, Md. Abdul Kayum; Kalam, Mehedi

    2014-01-01

    We propose a model for compact stars in low-mass X-ray binaries(LMXBs) namely KS 1731-260, EXO 1745-248 and 4U 1608-52. Here we investigate the physical phenomena of a compact star in the LMXBs. Using our model, we have calculated central density, surface density, mass(M) and red-shift for the above mentioned compact stars, which is very much consistent with the reported data. We also obtain the possible equation of state(EOS) of the stars which is physically acceptable.

  12. The Be X-ray Binary Outburst Zoo II

    Science.gov (United States)

    Kuehnel, M.; Kretschmar, P.; Nespoli, E.; Okazaki, A. T.; Schoenherr, G.; Wilson-Hodge, C. A.; Falkner, S.; Brand, T.; Anders, F.; Schwarm, F.-W.; Kreykenbohm, I.; Mueller, S.; Pottschmidt, K.; Fuerst, F.; Grinberg, V.; Wilms, J.

    2015-03-01

    We have continued our recently started systematic study of Be X-ray binary (BeXRB) outbursts. Specifically, we are developing a catalogue of outbursts including their basic properties based on nearly all available X-ray all-sky-monitors. These properties are derived by fitting asymmetric Gaussians to the outburst lightcurves. This model describes most of the outbursts covered by our preliminary catalogue well; only 13% of all datasets show more complex outburst shapes. Analyzing the basic properties, we reveal a strong correlation between the outburst length and the reached peak flux. As an example, we discuss possible models describing the observed correlation in EXO 2030+375.

  13. The ExoMars Raman Laser Spectrometer: Performance and Optimisation

    Science.gov (United States)

    Hutchinson, Ian; EDWARDS, Howell G. M.; Ingley, Richard; Waltham, Nick; ExoMars RLS Team

    2016-10-01

    The ExoMars rover, which is due for launch in 2020, will incorporate an analytical laboratory for interrogating the composition of drill cores retrieved from the near sub-surface of the planet. The laboratory includes a Raman spectrometer with a green laser (532 nm) that will be used to investigate the molecular and structural properties of the material within the samples. The ExoMars, Raman Laser Spectrometer (RLS) is expected to be the first instrument of its kind to be used on another planet.In preparation for the deployment and operation of the RLS instrument, a broad range of laboratory and fieldwork activities are currently being performed in order to ensure optimum scientific return from the mission. These studies include: science operations and data exploitation, terrestrial analogue studies (and laboratory simulations) and lessons learned from previous planetary mission experiences.Here we report on the status of the RLS science team activities related to studies of terrestrial analogues. This work includes the recovery and characterisation of appropriate samples from various field-site locations (e.g. clay based samples and materials recovered from dry deserts) that reflect the nature of the materials that are expected to be present in the landing site locations currently anticipated for the ExoMars rover mission. Other work includes the detailed analysis of such analogue samples using flight-like prototype instruments, both in-situ and in the laboratory.A summary of the results obtained from all of these studies is presented along with an overview of the anticipated performance capabilities of the instrument. Particular emphasis is placed on the design and performance of the camera system (including both the detector and data processing sub-systems).

  14. The ExoMars DREAMS scientific data archive

    Science.gov (United States)

    Schipani, P.; Marty, L.; Mannetta, M.; Esposito, F.; Molfese, C.; Aboudan, A.; Apestigue-Palacio, V.; Arruego-Rodríguez, I.; Bettanini, C.; Colombatti, G.; Debei, S.; Genzer, M.; Harri, A.-M.; Marchetti, E.; Montmessin, F.; Mugnuolo, R.; Pirrotta, S.; Wilson, C.

    2016-08-01

    DREAMS (Dust Characterisation, Risk Assessment, and Environment Analyser on the Martian Surface) is a payload accommodated on the Schiaparelli Entry and Descent Module (EDM) of ExoMars 2016, the ESA - Roscosmos mission to Mars successfully launched on 14 March 2016. The DREAMS data will be archived and distributed to the scientific community through the ESA's Planetary Science Archive (PSA). All data shall be compliant with NASA's Planetary Data System (PDS4) standards for formatting and labelling files. This paper summarizes the format and content of the DREAMS data products and associated metadata. The pipeline to convert the raw telemetries to the final products for the archive is sketched as well.

  15. Enabling Technologies for Characterizing Exoplanet Systems with Exo-C

    Science.gov (United States)

    Cahoy, Kerri Lynn; Belikov, Ruslan; Stapelfeldt, Karl R.; Chakrabarti, Supriya; Trauger, John T.; Serabyn, Eugene; McElwain, Michael W.; Pong, Christopher M.; Brugarolas, Paul

    2015-01-01

    The Exoplanet Science and Technology Definition Team's Internal Coronagraph mission design, called 'Exo-C', utilizes several technologies that have advanced over the past decade with support from the Exoplanet Exploration Program. Following the flow of photons through the telescope, the science measurement is enabled by (i) a precision pointing system to keep the target exoplanet system precisely positioned on the detector during the integration time, (ii) high-performance coronagraphs to block the parent star's light so that the planet's reflected light can be detected, (iii) a wavefront control system to compensate for any wavefront errors such as those due to thermal or mechanical deformations in the optical path, especially errors with high spatial frequencies that could cause contrast-reducing speckles, and (iv) an integral field spectrograph (IFS) that provides moderate resolution spectra of the target exoplanets, permitting their characterization and comparison with models and other data sets. Technologies such as the wavefront control system and coronagraphs will also benefit from other funded efforts in progress, such as the Wide Field Infrared Survey Telescope Astrophysics Focused Telescope Assets (WFIRST-AFTA) program. Similarly, the Exo-C IFS will benefit from the Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) demonstration. We present specific examples for each of these technologies showing that the state of the art has advanced to levels that will meet the overall scientific, cost, and schedule requirements of the Exo-C mission. These capabilities have matured with testbed and/or ground-telescope demonstrations and have reached a technological readiness level (TRL) that supports their inclusion in the baseline design for potential flight at the end of this decade. While additional work remains to build and test flight-like components (that concurrently meet science as well as size, weight, power, and environmental

  16. The ExoMars science data archive: status and plans

    Science.gov (United States)

    Heather, David; Barbarisi, Isa; Besse, Sebastien; Brumfitt, Jon; Lim, Tanya; Metcalfe, Leo; Villacorta, Antonio; PSA Team

    2016-10-01

    The ExoMars program is a co-operation between ESA and Roscosmos comprising two missions: the first, launched on 14 March 2016, includes the Trace Gas Orbiter and Schiaparelli lander; the second, due for launch in 2020, will be a Rover and Surface Platform (RSP). The Schiaparelli lander for the 2016 mission is due to land on 19th October, during this conference. The status of that landing will be included as part of this presentation.The archiving and management of the science data to be returned from ExoMars will require a significant development effort for the new Planetary Science Archive (PSA). These are the first data in the PSA to be formatted according to the new PDS4 Standards, and there are also significant differences in the way in which a scientist will want to query, retrieve, and use data from a suite of rover instruments as opposed to remote sensing instrumentation from an orbiter. NASA has a strong user community interaction for their rovers, and a similar approach to their 'Analysts Notebook' will be needed for the future PSA.In addition to the archiving interface itself, there are differences with the overall archiving process being followed for ExoMars compared to previous ESA planetary missions. The first level of data processing for the 2016 mission, from telemetry to raw, is completed by ESA at ESAC in Madrid, where the archive itself resides. Data continuously flow direct to the PSA, where after the given proprietary period, they will be released to the community via the user interfaces. For the rover mission, the data pipelines are being developed by European industry, in close collaboration with ESA PSA experts and with the instrument teams. The first level of data processing will be carried out for all instruments at ALTEC in Turin where the pipelines are developed, and from where the rover operations will also be run.This presentation will focus on the challenges involved in archiving the data from the ExoMars Program, and will outline the

  17. Exoplanet Direct Imaging: Coronagraph Probe Mission Study EXO-C

    Science.gov (United States)

    Stapelfeldt, Karl R.

    2013-01-01

    Flagship mission for spectroscopy of ExoEarths is a long-term priority for space astrophysics (Astro2010). Requires 10(exp 10) contrast at 3 lambda/D separation, ( (is) greater than 10,000 times beyond HST performance) and large telescope (is) greater than 4m aperture. Big step. Mission for spectroscopy of giant planets and imaging of disks requires 10(exp 9) contrast at 3 lambda/D (already demonstrated in lab) and (is) approximately 1.5m telescope. Should be much more affordable, good intermediate step.Various PIs have proposed many versions of the latter mission 17 times since 1999; no unified approach.

  18. Exo-inulinase of Aspergillus niger N402: A hydrolytic enzyme with significant transfructosylating activity

    NARCIS (Netherlands)

    Goosen, C.; Maarel, M.J. E.C. van der; Dijkhuizen, L.

    2008-01-01

    The purified exo-inulinase enzyme of Aspergillus niger N402 (AngInuE; heterologously expressed in Escherichia coli) displayed a sucrose:inulin (S/I) hydrolysis ratio of 2.3, characteristic for a typical exo-inulinase. The enzyme also had significant transfructosylating activity with increasing sucro

  19. Enantioselective synthesis of $\\alpha$-benzyloxy-$\\omega$-alkenals: application to the synthesis of (+)-exo-brevicomin, (+)-iso-exo-brevicomin, and (-)-isolaurepan

    OpenAIRE

    Prasad, KR; Anbarasan, P

    2007-01-01

    The enantioselective synthesis of alpha-benzyloxy aldehydes containing a terminal alkene was carried out from chiral Pool L-(+)tartaric acid by employing the stereoselective reduction of a 1,4-diketone as the key step. The synthetic utility of these aldehydes was demonstrated in the synthesis of pine beetle pheromones (+)-exo-brevicomin, (+)-iso-exo-brevicomin and a formal synthesis of 2,7cis-disubstituted oxepane (-)-isolaurepan.

  20. Maximizing the ExoEarth Candidate Yield from a Future Direct Imaging Mission

    CERN Document Server

    Stark, Christopher C; Mandell, Avi; Robinson, Tyler D

    2014-01-01

    ExoEarth yield is a critical science metric for future exoplanet imaging missions. Here we estimate exoEarth candidate yield using single visit completeness for a variety of mission design and astrophysical parameters. We review the methods used in previous yield calculations and show that the method choice can significantly impact yield estimates as well as how the yield responds to mission parameters. We introduce a method, called Altruistic Yield Optimization, that optimizes the target list and exposure times to maximize mission yield, adapts maximally to changes in mission parameters, and increases exoEarth candidate yield by up to 100% compared to previous methods. We use Altruistic Yield Optimization to estimate exoEarth candidate yield for a large suite of mission and astrophysical parameters using single visit completeness. We find that exoEarth candidate yield is most sensitive to telescope diameter, followed by coronagraph inner working angle, followed by coronagraph contrast, and finally coronagrap...

  1. Raman Laser Spectrometer for 2020 ExoMars

    Science.gov (United States)

    Moral, Andoni G.; Pérez, Carlos; INTA, University of Valladolid, INSA, Leicester University, IRAP, RAL, OHB

    2016-10-01

    The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission.ExoMars 2020 main scientific objective is "Searching for evidence of past and present life on Mars".Raman Spectroscopy is used to analyze the vibrational modes of a substance either in the solid, liquid or gas state. It relies on the inelastic scattering (Raman Scattering) of monochromatic light produced by atoms and molecules. The radiation-matter interaction results in the energy of the exciting photons to be shifted up or down. The shift in energy appears as a spectral distribution and therefore provides an unique fingerprint by which the substances can be identified and structurally analyzed.The RLS is being developed by an European Consortium composed by Spanish, UK, French and German partners. It will perform Raman spectroscopy on crushed powdered samples, obtained from 2 meters depth under Mars surface, inside the Rover's Analytical Laboratory Drawer.After a wide campaign for evaluating Instrument performances by means of simulation tools and development of an instrument prototype, Instrument Structural and Thermal Model was successfully delivered on February 2015, and the Engineering and Qualification Model has been manufactured and is expected to be delivered by November 2016, after a testing campaign developed during Q2 & Q3 of 2016.A summary of main Instrument performances obtained during the last months, achieving high levels of spectral resolution and accuracy in the obtained spectra.

  2. ExoMars Raman laser spectrometer for Exomars

    Science.gov (United States)

    Rull, F.; Sansano, A.; Díaz, E.; Canora, C. P.; Moral, A. G.; Tato, C.; Colombo, M.; Belenguer, T.; Fernández, M.; Manfredi, J. A. R.; Canchal, R.; Dávila, B.; Jiménez, A.; Gallego, P.; Ibarmia, S.; Prieto, J. A. R.; Santiago, A.; Pla, J.; Ramos, G.; Díaz, C.; González, C.

    2011-10-01

    The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission. ExoMars 2018 main Scientific objective is "Searching for evidence of past and present life on Mars". Raman Spectroscopy is used to analyze the vibrational modes of a substance either in the solid, liquid or gas state. It relies on the inelastic scattering (Raman Scattering) of monochromatic light produced by atoms and molecules. The radiation-matter interaction results in the energy of the exciting photons to be shifted up or down. The shift in energy appears as a spectral distribution and therefore provides an unique fingerprint by which the substances can be identified and structurally analyzed. The RLS is being developed by an European Consortium composed by Spanish, French, German and UK partners. It will perform Raman spectroscopy on crushed powdered samples inside the Rover's Analytical Laboratory Drawer. Instrument performances are being evaluated by means of simulation tools and development of an instrument prototype.

  3. EXO-ZODI MODELING FOR THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Grant M.; Wyatt, Mark C.; Panić, Olja; Shannon, Andrew [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Bailey, Vanessa; Defrère, Denis; Hinz, Philip M.; Rieke, George H.; Skemer, Andrew J.; Su, Katherine Y. L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Bryden, Geoffrey; Mennesson, Bertrand; Morales, Farisa; Serabyn, Eugene [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Danchi, William C.; Roberge, Aki; Stapelfeldt, Karl R. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771 (United States); Haniff, Chris [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Lebreton, Jérémy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Millan-Gabet, Rafael [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); and others

    2015-02-01

    Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10{sup –4} the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars.

  4. Binary effectivity rules

    DEFF Research Database (Denmark)

    Keiding, Hans; Peleg, Bezalel

    2006-01-01

    is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...... effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann-Morgenstern solutions play an important role in this characterization...

  5. Systems astrobiology for a reliable biomarker on exo-worlds

    Science.gov (United States)

    Chela Flores, Julian

    2013-04-01

    Although astrobiology is a science midway between biology and astrophysics, it has surprisingly remained largely disconnected from recent trends in certain branches of both of these disciplines. Aiming at discovering how systems properties emerge has proved valuable in chemistry and in biology and should also yield insights into astrobiology. This is feasible since new large data banks in the case of astrobiology are of a geophysical/astronomical kind, rather than the also large molecular biology data that are used for questions related firstly, to genetics in a systems context and secondly, to biochemistry. The application of systems biology is illustrated for our own planetary system, where 3 Earth-like planets are within the habitable zone of a G2V star and where the process of photosynthesis has led to a single oxygenic atmosphere that was triggered during the Great Oxidation Event some 2,5 billion years before the present. The significance of the biogenic origin of a considerable fraction of our atmosphere has been discussed earlier (Kiang et al., 2007). Bonding of O2 ensures that it is stable enough to accumulate in a world's atmosphere if triggered by a living process. The reduction of F and Cl deliver energy release per e+-transfer, but unlike O2 the weaker bonding properties inhibit large atmospheric accumulation (Catling et al., 2005). The evolution of O2-producing photosynthesis is very likely on exo-worlds (Wolstencroft and Raven, 2002). With our simplifying assumption of evolutionary convergence, we show how to probe for a reliable biomarker in the exo-atmospheres of planets, or their satellites, orbiting stars of different luminosities and ages (Chela-Flores, 2013). We treat the living process as a system of exo-environments capable of radically modifying their geology and atmospheres, both for exo-planets, and especially for exo-moons, the presence of which can be extracted from the Kepler data (Kipping et al., 2012). What we are learning about the

  6. Expression of an Exo-β-glucanase Gene Is Specifically Related to Lily Pollen Germination and Pollen Tube Growth

    Institute of Scientific and Technical Information of China (English)

    LIU Xizhen; HUANG Jian; GAO Rongfu; LI Yiqin

    2005-01-01

    The present study is expected to provide better understanding of how exo-β-glucanase acts on the biochemo-rheological property of the cell wall, and thus the regulation mechanism of pollen tube growth. A polymerase chain reaction (PCR)-based strategy and cDNA library screening were used to clone an exo-β-glucanase gene (LP-ExoI) from Lilium longiflorum pollen tubes. The LP-ExoI sequence showed a high level of homology to that of reported plant exo-β-glucan hydrolases. Phylogenetic analysis demonstrated that there was close relationship between LP-ExoI and other exo-glucan hydrolases in Poacea plants. Northern analysis indicated that LP-ExoI transcripts stored in pollen grains at low levels; LP-ExoI transcription level enhanced at 2 h after the onset of pollen incubation and remained relatively high during pollen tube elongation. Moreover, the expression of LP-ExoI was undetectable in petals, filaments, stigmas, styles, ovaries, leaves, and stems. These results suggest that LP-ExoI gene is a late pollen gene, specifically contributing to the regulation of lily pollen germination and pollen tube growth.

  7. Nuclear localization of human DNA mismatch repair protein exonuclease 1 (hEXO1)

    DEFF Research Database (Denmark)

    Knudsen, Nina Østergaard; Nielsen, Finn Cilius; Vinther, Lena

    2007-01-01

    localization signals (NLSs) in hEXO1. Using fluorescent fusion proteins, we show that the sequence 418KRPR421, which exhibit strong homology to other monopartite NLS sequences, is responsible for correct nuclear localization of hEXO1. This NLS sequence is located in a region that is also required for hEXO1......Human exonuclease 1 (hEXO1) is implicated in DNA mismatch repair (MMR) and mutations in hEXO1 may be associated with hereditary nonpolyposis colorectal cancer (HNPCC). Since the subcellular localization of MMR proteins is essential for proper MMR function, we characterized possible nuclear...... interaction with hMLH1 and we show that defective nuclear localization of hEXO1 mutant proteins could be rescued by hMLH1 or hMSH2. Both hEXO1 and hMLH1 form complexes with the nuclear import factors importin beta/alpha1,3,7 whereas hMSH2 specifically recognizes importin beta/alpha3. Taken together, we infer...

  8. Maximizing the ExoEarth candidate yield from a future direct imaging mission

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Christopher C. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Roberge, Aki; Mandell, Avi [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Robinson, Tyler D., E-mail: christopher.c.stark@nasa.gov [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2014-11-10

    ExoEarth yield is a critical science metric for future exoplanet imaging missions. Here we estimate exoEarth candidate yield using single visit completeness for a variety of mission design and astrophysical parameters. We review the methods used in previous yield calculations and show that the method choice can significantly impact yield estimates as well as how the yield responds to mission parameters. We introduce a method, called Altruistic Yield Optimization, that optimizes the target list and exposure times to maximize mission yield, adapts maximally to changes in mission parameters, and increases exoEarth candidate yield by up to 100% compared to previous methods. We use Altruistic Yield Optimization to estimate exoEarth candidate yield for a large suite of mission and astrophysical parameters using single visit completeness. We find that exoEarth candidate yield is most sensitive to telescope diameter, followed by coronagraph inner working angle, followed by coronagraph contrast, and finally coronagraph contrast noise floor. We find a surprisingly weak dependence of exoEarth candidate yield on exozodi level. Additionally, we provide a quantitative approach to defining a yield goal for future exoEarth-imaging missions.

  9. Exo1 and Mre11 execute meiotic DSB end resection in the protist Tetrahymena.

    Science.gov (United States)

    Lukaszewicz, Agnieszka; Shodhan, Anura; Loidl, Josef

    2015-11-01

    The resection of 5'-DNA ends at a double-strand break (DSB) is an essential step in recombinational repair, as it exposes 3' single-stranded DNA (ssDNA) tails for interaction with a repair template. In mitosis, Exo1 and Sgs1 have a conserved function in the formation of long ssDNA tails, whereas this step in the processing of programmed meiotic DSBs is less well-characterized across model organisms. In budding yeast, which has been most intensely studied in this respect, Exo1 is a major meiotic nuclease. In addition, it exerts a nuclease-independent function later in meiosis in the conversion of DNA joint molecules into ZMM-dependent crossovers. In order to gain insight into the diverse meiotic roles of Exo1, we investigated the effect of Exo1 deletion in the ciliated protist Tetrahymena. We found that Exo1 together with Mre11, but without the help of Sgs1, promotes meiotic DSB end resection. Resection is completely eliminated only if both Mre11 and Exo1 are missing. This is consistent with the yeast model where Mre11 promotes resection in the 3'-5' direction and Exo1 in the opposite 5'-3' direction. However, while the endonuclease activity of Mre11 is essential to create an entry site for exonucleases and hence to start resection in budding yeast, Tetrahymena Exo1 is able to create single-stranded DNA in the absence of Mre11. Excluding a possible contribution of the Mre11 cofactor Sae2 (Com1) as an autonomous endonuclease, we conclude that there exists another unknown nuclease that initiates DSB processing in Tetrahymena. Consistent with the absence of the ZMM crossover pathway in Tetrahymena, crossover formation is independent of Exo1.

  10. Neural network for exo-atmospheric target discrimination

    Science.gov (United States)

    Resch, Cheryl L.

    1998-09-01

    In response to a threat missile, an interceptor missile with a kinetic warhead (KW) is launched with the intention of intercepting and killing the lethal reentry vehicle (RV) in the exo-atmosphere before it reaches its target. Data from an IR sensor on-board the KW is to be used to discriminate the RV from the other pieces in the field of view. A time-delay neural network (TDNN) is proposed for discrimination. A TDNN was trained using simulated data, and tested using simulated and flight data. The flight data includes IR signatures for RVs, boosters, and thrust termination debris. The TDNN is able to distinguish RVs from other missile parts and debris. This paper describes the performance of a TDNN for discrimination in ballistic missile defense when tested using flight data.

  11. Maximized ExoEarth Candidate Yields for Starshades

    CERN Document Server

    Stark, Christopher C; Lisman, Doug; Cady, Eric; Savransky, Dmitry; Roberge, Aki; Mandell, Avi M

    2016-01-01

    The design and scale of a future mission to directly image and characterize potentially Earth-like planets will be impacted, to some degree, by the expected yield of such planets. Recent efforts to increase the estimated yields, by creating observation plans optimized for the detection and characterization of Earth-twins, have focused solely on coronagraphic instruments; starshade-based missions could benefit from a similar analysis. Here we explore how to prioritize observations for a starshade given the limiting resources of both fuel and time, present analytic expressions to estimate fuel use, and provide efficient numerical techniques for maximizing the yield of starshades. We implemented these techniques to create an approximate design reference mission code for starshades and used this code to investigate how exoEarth candidate yield responds to changes in mission, instrument, and astrophysical parameters for missions with a single starshade. We find that a starshade mission operates most efficiently so...

  12. Predicting the frequencies of diverse exo-planetary systems

    CERN Document Server

    Greaves, J S; Wyatt, M C; Beichman, C A; Bryden, G

    2007-01-01

    Extrasolar planetary systems range from hot Jupiters out to icy comet belts more distant than Pluto. We explain this diversity in a model where the mass of solids in the primordial circumstellar disk dictates the outcome. The star retains measures of the initial heavy-element (metal) abundance that can be used to map solid masses onto outcomes, and the frequencies of all classes are correctly predicted. The differing dependences on metallicity for forming massive planets and low-mass cometary bodies are also explained. By extrapolation, around two-thirds of stars have enough solids to form Earth-like planets, and a high rate is supported by the first detections of low-mass exo-planets.

  13. Exo-C: Mission and Science Payload Design

    Science.gov (United States)

    Dekens, Frank G.; Stapelfeldt, Karl R.; Warfield, Keith; Unwin, Stephen C.; Exo-C Science; Technology Definition Team, Exo-C JPL Study Design Team

    2015-01-01

    We present NASA's Exoplanet Coronagraph (Exo-C) mission design and science payload completed as part of a probe-class concept study under consideration for launch following JWST. The payload consists of an unobscured Cassegrain telescope with a 1.4-m clear aperture, a barrel assembly, and an internal coronagraph instrument. The mission has a 3 year lifetime and is in a highly stable Earth-trailing orbit. The coronagraph instrument is mounted laterally on the anti-Sun side of the telescope, obviating the need for high incidence reflections and better isolating it from spacecraft disturbances. The instrument has both an Imaging Camera and an Integral Field Spectrograph (IFS). The former obtains filter imaging with 1e-9 raw contrast from 2 - 20 λ/D in radius, while the IFS delivers the same contrast with spectral resolution of R = 70 from 450 to 1000 nm, but with a reduced outer working angle.The Exo-C science performance requirements are achieved with a specialized observatory design enabled by several new technologies. The telescope is designed for precision pointing and high stability to maintain a slowly evolving speckle pattern. Vibration isolation is achieved with two stages between the reaction wheels and the science payload. The solar arrays and high gain antenna are body-fixed, and a stiff barrel assembly is used as the telescope metering structure. Telescope pointing is updated at a high rate by monitoring the bright science target star with a low order wavefront sensor and driving a fine steering mirror for compensation. Active thermal control is used to minimize thermal drifts of the telescope, instrument, and barrel assemblies. Stability analyses via modeling of the structural, thermal, and optical performance of this configuration show that the proposed mission configuration would enable unprecedented exoplanet and circumstellar disk science with direct imaging.

  14. Exo-Higgs at 750 GeV and Genesis of Baryons

    CERN Document Server

    Davoudiasl, Hooman; Zhang, Cen

    2016-01-01

    We propose that the diphoton excess at 750~GeV reported by ATLAS and CMS is due to the decay of an ${\\it exo-Higgs}$ scalar $\\eta$ associated with the breaking of a new $SU(2)_e$ symmetry, dubbed ${\\it exo-spin}$. New fermions, ${\\it exo-quarks}$ and ${\\it exo-leptons}$, get TeV-scale masses through Yukawa couplings with $\\eta$ and generate its couplings to gluons and photons at 1-loop. The matter content of our model yields a $B-L$ anomaly under $SU(2)_e$, whose breaking we assume entails a first order phase transition. A non-trivial $B-L$ asymmetry may therefore be generated in the early universe, potentially providing a baryogenesis mechanism through the Standard Model (SM) sphaleron processes. The spontaneous breaking of $SU(2)_e$ can in principle directly lead to electroweak symmetry breaking, thereby accounting for the proximity of the mass scales of the SM Higgs and the exo-Higgs. Our model can be distinguished from those comprising a singlet scalar and vector fermions by the discovery of TeV scale exo...

  15. The ExoMars science data archive: status and plans

    Science.gov (United States)

    Heather, David

    2016-07-01

    The ExoMars program, a cooperation between ESA and Roscosmos, comprises two missions: the Trace Gas Orbiter, to be launched in 2016, and a rover and surface platform, due for launch in 2018. This will be the first time ESA has operated a rover, and the archiving and management of the science data to be returned will require a significant effort in development of the new Planetary Science Archive (PSA). The ExoMars mission data will also be formatted according to the new PDS4 Standards, based in XML, and this will be the first data of that format to be archived in the PSA. There are significant differences in the way in which a scientist will want to query, retrieve, and use data from a suite of rover instruments as opposed to remote sensing instrumentation from an orbiter. The PSA data holdings and the accompanying services are currently driven more towards the management of remote sensing data, so some significant changes will be needed. Among them will be a much closer link to the operational information than is currently available for our missions. NASA have a strong user community interaction with their analysts notebook, which provides detailed operational information to explain why, where and when operations took place. A similar approach will be needed for the future PSA, which is currently being designed. In addition to the archiving interface itself, there are differences with the overall archiving process being followed for ExoMars compared to previous ESA planetary missions. The Trace Gas Orbiter data pipelines for the first level of processing from telemetry to raw data, will be hosted directly by ESA's ground segment at ESAC in Madrid, where the archive itself resides. Data will have a continuous flow direct to the PSA, where after the given proprietary period, it will be directly released to the community via the new user interface. For the rover mission, the data pipelines are being developed by European industry, in close collaboration with ESA PSA

  16. The ExoMars PanCam Instrument

    Science.gov (United States)

    Griffiths, Andrew; Coates, Andrew; Muller, Jan-Peter; Jaumann, Ralf; Josset, Jean-Luc; Paar, Gerhard; Barnes, David

    2010-05-01

    The ExoMars mission has evolved into a joint European-US mission to deliver a trace gas orbiter and a pair of rovers to Mars in 2016 and 2018 respectively. The European rover will carry the Pasteur exobiology payload including the 1.56 kg Panoramic Camera. PanCam will provide multispectral stereo images with 34 deg horizontal field-of-view (580 microrad/pixel) Wide-Angle Cameras (WAC) and (83 microrad/pixel) colour monoscopic "zoom" images with 5 deg horizontal field-of-view High Resolution Camera (HRC). The stereo Wide Angle Cameras (WAC) are based on Beagle 2 Stereo Camera System heritage [1]. Integrated with the WACs and HRC into the PanCam optical bench (which helps the instrument meet its planetary protection requirements) is the PanCam interface unit (PIU); which provides image storage, a Spacewire interface to the rover and DC-DC power conversion. The Panoramic Camera instrument is designed to fulfil the digital terrain mapping requirements of the mission [2] as well as providing multispectral geological imaging, colour and stereo panoramic images and solar images for water vapour abundance and dust optical depth measurements. The High Resolution Camera (HRC) can be used for high resolution imaging of interesting targets detected in the WAC panoramas and of inaccessible locations on crater or valley walls. Additionally HRC will be used to observe retrieved subsurface samples before ingestion into the rest of the Pasteur payload. In short, PanCam provides the overview and context for the ExoMars experiment locations, required to enable the exobiology aims of the mission. In addition to these baseline capabilities further enhancements are possible to PanCam to enhance it's effectiveness for astrobiology and planetary exploration: 1. Rover Inspection Mirror (RIM) 2. Organics Detection by Fluorescence Excitation (ODFE) LEDs [3-6] 3. UVIS broadband UV Flux and Opacity Determination (UVFOD) photodiode This paper will discuss the scientific objectives and resource

  17. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    2006-01-01

    Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

  18. A thermostable exo-β-fructosidase immobilised through rational design.

    Science.gov (United States)

    Martínez, Duniesky; Cutiño-Avila, Bessy; Pérez, Enrique Rosendo; Menéndez, Carmen; Hernández, Lázaro; Del Monte-Martínez, Alberto

    2014-02-15

    Thermotoga maritima exo-β-fructosidase (BfrA) secreted by a recombinant Pichia pastoris strain was optimally immobilised on Glyoxyl-Sepharose CL 4B using the Rational Design of Immobilised Derivatives (RDID) strategy. Covalent attachment of the N-glycosylated BfrA onto the activated support at pH 10 allowed total recovery of the loaded enzyme and its activity. The immobilisation process caused no variation in the catalytic properties of the enzyme and allowed further enhancement of the thermal stability. Complete inversion of cane sugar (2.04 M) in a batch stirred tank reactor at 60 °C was achieved with a productivity of 22.2 g of substrate hydrolysed/gram of biocatalyst/hour. Half-life of the immobilised enzyme of 5 days at 60 °C was determined in a continuously operated fixed-bed column reactor. Our results promote the applicability of the BfrA-immobilised biocatalyst for the complete hydrolysis of concentrated sucrose solutions under industrial conditions, especially at a high reaction temperature.

  19. Formation and Structure of Low Density Exo-Neptunes

    CERN Document Server

    Rogers, Leslie A; Lissauer, Jack J; Seager, Sara

    2011-01-01

    Kepler has found hundreds of Neptune-size (2-6 R_Earth) planet candidates within 0.5 AU of their stars. The nature of the vast majority of these planets is not known because their masses have not been measured. Using theoretical models of planet formation, evolution and structure, we explore the range of minimum plausible masses for low-density exo-Neptunes. We focus on highly irradiated planets with T_eq>=500K. We consider two separate formation pathways for low-mass planets with voluminous atmospheres of light gases: core nucleated accretion and outgassing of hydrogen from dissociated ices. We show that Neptune-size planets at T_eq=500K with masses as small as a few times that of Earth can plausibly be formed core nucleated accretion coupled with subsequent inward migration. We also derive a limiting low-density mass-radius relation for rocky planets with outgassed hydrogen envelopes but no surface water. Rocky planets with outgassed hydrogen envelopes typically have computed radii well below 3 R_Earth. For...

  20. Binary mask programmable hologram.

    Science.gov (United States)

    Tsang, P W M; Poon, T-C; Zhou, Changhe; Cheung, K W K

    2012-11-19

    We report, for the first time, the concept and generation of a novel Fresnel hologram called the digital binary mask programmable hologram (BMPH). A BMPH is comprised of a static, high resolution binary grating that is overlaid with a lower resolution binary mask. The reconstructed image of the BMPH can be programmed to approximate a target image (including both intensity and depth information) by configuring the pattern of the binary mask with a simple genetic algorithm (SGA). As the low resolution binary mask can be realized with less stringent display technology, our method enables the development of simple and economical holographic video display.

  1. Anionic cascade reactions. One-pot assembly of (Z-chloro-exo-methylenetetrahydrofurans from β-hydroxyketones

    Directory of Open Access Journals (Sweden)

    István E. Markó

    2013-07-01

    Full Text Available The assembly of (Z-chloro-exo-methylenetetrahydrofurans by an original and connective anionic cascade sequence is reported. Base-catalysed condensation of β-hydroxyketones with 1,1-dichloroethylene generates, in moderate to good yields, the corresponding (Z-chloro-exo-methylenetetrahydrofurans. Acidic treatment of this motif leads to several unexpected dimers, possessing unique structural features.

  2. ENHANCED PRODUCTION OF EXO-POLYGALACTURONASE FROM AGRO-BASED PRODUCTS BY ASPERGILLUS SOJAE

    Directory of Open Access Journals (Sweden)

    Ali Oguz Buyukkileci

    2011-06-01

    Full Text Available Aspergillus sojae has been previously shown to produce exo-polygalacturonase (exo-PG in synthetic media, where the potential of the organism to utilize agricultural substrates was not considered so far. In this study, the utilization of agro-based products was taken into account in the enhanced production of exo-PG using an A. sojae mutant by applying statistical design methods. Complex sources (orange peel, wheat bran, and corn meal, simple sugar sources (glucose, maltrin, and sugar beet syrup, and two phosphate salts were screened using D-optimal design method. Orange peel yielded the highest exo-PG activity with all simple sugars and phosphate sources. According to the results of response surface methodology (RSM, the optimum concentrations of orange peel, sugar beet syrup, and (NH42SO4 were found to be 10, 60, and 8 g L-1, respectively. The exo-PG activity under these conditions was 145.4 U m L-1 in shake flask cultures. In bioreactor studies enzyme production was induced at low pH values; thus highest production was obtained under uncontrolled pH conditions, in which the pH dropped to 2.0 in 72 h. As a result high exo-PG could be produced by an A. sojae mutant using a cost-effective medium containing agro-industrial substrates. Another important advantageous outcome was the low optimal pH, which is especially desired in industrial fermentations prone to contamination problems. In fact this highlights the easy adaptation of this fermentation to industrial scales.

  3. Sae2, Exo1 and Sgs1 collaborate in DNA double-strand break processing

    OpenAIRE

    Mimitou, Eleni P.; Symington, Lorraine S.

    2008-01-01

    DNA ends exposed after introduction of double-strand breaks (DSBs) undergo 5′-3′ nucleolytic degradation to generate single-stranded DNA (ssDNA), the substrate for binding by the Rad51 protein to initiate homologous recombination. This process is poorly understood in eukaryotes, but several factors have been implicated, including the Mre11 complex (Mre11-Rad50-Xrs2/NBS1), Sae2/CtIP/Ctp1 and Exo1. Here we demonstrate that yeast Exo1 nuclease and Sgs1 helicase function in alternate pathways for...

  4. Exo-metabolome of some fungal isolates growing on cork-based medium

    DEFF Research Database (Denmark)

    Barreto, M. C.; Frisvad, Jens Christian; Larsen, Thomas Ostenfeld;

    2011-01-01

    are produced by the studied fungal species, both in cork medium or in cork medium added with C. sitophila extracts. However, the addition of C. sitophila extract to the cork medium enhanced the growth of the other studied fungal isolates and altered the respective exo-metabolome profile, leading...... they can be dependent of the remains of former colonizers. In fact, the production of the exo-metabolites by the studied fungal isolates suggests that, under the used experimental conditions, they appear to play an important role in fungal interactions amongst the cork mycoflora....

  5. Simultaneous amyloglucosidase and exo-polygalacturonase production by Aspergillus niger using solid-state fermentation

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Vieira Costa

    2007-09-01

    Full Text Available Amyloglucosidase (AMG and exo-polygalacturonase (exo-PG were simultaneously produced by two different strains of Aspergillus niger in solid-state fermentation (SSF using defatted rice-bran as substrate. The effect of Aspergillus niger strain (t0005/007-2 and/or CCT 3312, inoculum type (spore suspension or fermented bran and addition of inducers (pectin and/or starch to the culture media was studied using a 3² x 2¹ factorial experimental design. The production of AMG and exo-PG was significantly affected by fungal strain and inoculum type but inducers had no effect. The maximum yields obtained were 1310 U/g dm for AMG using a spore suspension of A. niger CCT 3312 and 50.2 U/g dm for exo-PG production, using A. niger t0005/007-2 and fermented bran as inoculum. The yields obtained represented acceptable values in comparison with data available in the literature and indicated that defatted rice-bran was a good nutrient source.As enzimas amiloglicosidase (AMG e exo-poligalacturonase (exo-PG foram produzidas simultaneamente por duas cepas de Aspergillus niger, através de fermentação em estado sólido usando farelo de arroz desengordurado como substrato. Foram avaliados os efeitos da cepa de Aspergillus niger, tipo de inóculo e adição de indutores no meio de cultura, utilizando-se um planejamento experimental fracionário 3² x 2¹. O máximo rendimento obtido foi 1310 U/g ms para a produção de AMG e 50,2 U/g ms para a exo-PG. Comparando-se estes resultados com dados da literatura pode-se dizer que os rendimentos obtidos foram aceitáveis e indicam que o farelo de arroz desengordurado é uma boa fonte de nutrientes. A produção de AMG e exo-PG foi significativamente afetada pelas variáveis cepa de A. niger e tipo de inóculo, enquanto a variável indutor não apresentou influência significativa na produção destas enzimas.

  6. Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission

    Science.gov (United States)

    Vandaele, A. C.; Neefs, E.; Drummond, R.; Thomas, I. R.; Daerden, F.; Lopez-Moreno, J.-J.; Rodriguez, J.; Patel, M. R.; Bellucci, G.; Allen, M.; Altieri, F.; Bolsée, D.; Clancy, T.; Delanoye, S.; Depiesse, C.; Cloutis, E.; Fedorova, A.; Formisano, V.; Funke, B.; Fussen, D.; Geminale, A.; Gérard, J.-C.; Giuranna, M.; Ignatiev, N.; Kaminski, J.; Karatekin, O.; Lefèvre, F.; López-Puertas, M.; López-Valverde, M.; Mahieux, A.; McConnell, J.; Mumma, M.; Neary, L.; Renotte, E.; Ristic, B.; Robert, S.; Smith, M.; Trokhimovsky, S.; Vander Auwera, J.; Villanueva, G.; Whiteway, J.; Wilquet, V.; Wolff, M.

    2015-12-01

    The NOMAD spectrometer suite on the ExoMars Trace Gas Orbiter will map the composition and distribution of Mars' atmospheric trace species in unprecedented detail, fulfilling many of the scientific objectives of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument is a combination of three channels, covering a spectral range from the UV to the IR, and can perform solar occultation, nadir and limb observations. In this paper, we present the science objectives of the instrument and how these objectives have influenced the design of the channels. We also discuss the expected performance of the instrument in terms of coverage and detection sensitivity.

  7. 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

  8. ExoGeoLab Test Bench for Landers, Rovers and Instruments

    Science.gov (United States)

    Foing, B. H.

    2009-04-01

    In the frame of ESTEC technology and research pilot project, we have started a small pilot facility with a ExoGeoLab and a mini-Habitat, supported by two design and control offices in the European Space Incubator (ESI), as well as infrastructure support and manpower. We have in addition to contribution on external instruments and manpower from partner institutes. From this test bench and kit of ExoGeoLab instruments, we plan to operate comprehensive instruments packages that could help in the technical research and science preparation of lander/rover missions studied in the frame of Cosmic Vision or the Exploration programme. The ExoGeoLab research incubator project includes a sequence of activities: - Data analysis and interpretation of remote sensing data (MEX, SMART-1, VEX, Cassini-Huygens) and in-situ (Huygens, MER) , and merging of multi-scale data sets - Procurement and integration of geophysical, geochemical and astrobiological breadboard instruments in an surface station and rover (ExoGeoLab) - Research operations and exploitation of ExoGeoLab test bench for various conceptual configurations (Moon, Mars, NEO, Titan) - Contribution to the exploitation of surface lander results (MER, Phenix, MSL, preparation Exomars) - Scientific simulation of planetary surfaces using laboratory and modelling tools - Support research for definition and design of science surface packages on the Moon, Mars, NEO, Titan - Research support to community preparation of payload for surface lander opportunities Specific goals and methods of ESTEC ExoGeoLab: we have started to integrate instruments in an ExoGeoLab crossing various techniques. The methodic steps for this hands-on research are: 1) We have procured and adapted instruments to equip a mid-size ExoGeoRover (made available in collaboration with ESTEC robotics section), and a small surface station. 2) This terrestrial payload (instruments, sensors, data handling) will be deployed, operated and used as collaborative research

  9. Molecular modeling and computational analyses suggests that the Sinorhizobium meliloti periplasmic regulator protein ExoR adopts a superhelical fold and is controlled by a unique mechanism of proteolysis.

    Science.gov (United States)

    Wiech, Eliza M; Cheng, Hai-Ping; Singh, Shaneen M

    2015-03-01

    The Sinorhizobium meliloti periplasmic ExoR protein and the ExoS/ChvI two-component system form a regulatory mechanism that directly controls the transformation of free-living to host-invading cells. In the absence of crystal structures, understanding the molecular mechanism of interaction between ExoR and the ExoS sensor, which is believed to drive the key regulatory step in the invasion process, remains a major challenge. In this study, we present a theoretical structural model of the active form of ExoR protein, ExoRm , generated using computational methods. Our model suggests that ExoR possesses a super-helical fold comprising 12 α-helices forming six Sel1-like repeats, including two that were unidentified in previous studies. This fold is highly conducive to mediating protein-protein interactions and this is corroborated by the identification of putative protein binding sites on the surface of the ExoRm protein. Our studies reveal two novel insights: (a) an extended conformation of the third Sel1-like repeat that might be important for ExoR regulatory function and (b) a buried proteolytic site that implies a unique proteolytic mechanism. This study provides new and interesting insights into the structure of S. meliloti ExoR, lays the groundwork for elaborating the molecular mechanism of ExoRm cleavage, ExoRm -ExoS interactions, and studies of ExoR homologs in other bacterial host interactions.

  10. Management of flight control for "ExoMars-2018" robotic interplanetary space station

    Science.gov (United States)

    Shirshakov, A. E.; Artyukhov, M. I.; Kazakevich, Yu. V.; Kalashnikov, A. I.

    2015-12-01

    The article covers the current status of activities on development of "ExoMars-2018" robotic interplanetary space station in terms of SC Composite flight program, results of onboard systems interaction functional design study. Organizational structure of p]Russian part of ground control and management of its interaction with European part of ground control are proposed.

  11. ESA ExoMars: Pre-launch PanCam Geometric Modeling and Accuracy Assessment

    Science.gov (United States)

    Li, D.; Li, R.; Yilmaz, A.

    2014-08-01

    ExoMars is the flagship mission of the European Space Agency (ESA) Aurora Programme. The mobile scientific platform, or rover, will carry a drill and a suite of instruments dedicated to exobiology and geochemistry research. As the ExoMars rover is designed to travel kilometres over the Martian surface, high-precision rover localization and topographic mapping will be critical for traverse path planning and safe planetary surface operations. For such purposes, the ExoMars rover Panoramic Camera system (PanCam) will acquire images that are processed into an imagery network providing vision information for photogrammetric algorithms to localize the rover and generate 3-D mapping products. Since the design of the ExoMars PanCam will influence localization and mapping accuracy, quantitative error analysis of the PanCam design will improve scientists' awareness of the achievable level of accuracy, and enable the PanCam design team to optimize its design to achieve the highest possible level of localization and mapping accuracy. Based on photogrammetric principles and uncertainty propagation theory, we have developed a method to theoretically analyze how mapping and localization accuracy would be affected by various factors, such as length of stereo hard-baseline, focal length, and pixel size, etc.

  12. Pseudomonas aeruginosa Type III Secretory Toxin ExoU and Its Predicted Homologs

    Directory of Open Access Journals (Sweden)

    Teiji Sawa

    2016-10-01

    Full Text Available Pseudomonas aeruginosa ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in immunocompromised patients. Through use of a recently updated bacterial genome database, protein sequences predicted to be homologous to Ps. aeruginosa ExoU were identified in 17 other Pseudomonas species (Ps. fluorescens, Ps. lundensis, Ps. weihenstephanensis, Ps. marginalis, Ps. rhodesiae, Ps. synxantha, Ps. libanensis, Ps. extremaustralis, Ps. veronii, Ps. simiae, Ps. trivialis, Ps. tolaasii, Ps. orientalis, Ps. taetrolens, Ps. syringae, Ps. viridiflava, and Ps. cannabina and 8 Gram-negative bacteria from three other genera (Photorhabdus, Aeromonas, and Paludibacterium. In the alignment of the predicted primary amino acid sequences used for the phylogenetic analyses, both highly conserved and nonconserved parts of the toxin were discovered among the various species. Further comparative studies of the predicted ExoU homologs should provide us with more detailed information about the unique characteristics of the Ps. aeruginosa ExoU toxin.

  13. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Science.gov (United States)

    Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic proc...

  14. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS mediated cardiomyocyte hypertrophy

    NARCIS (Netherlands)

    Tigchelaar, Wardit; Yu, Hongjuan; De Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Sillje, Herman H W

    2015-01-01

    Recently, a genetic variant in the mitochondrial exo/endo nuclease EXOG, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrop

  15. Exo-polygalacturonase production by Penicillium roqueforti on pumpkin oil cake in solid state fermentation

    Directory of Open Access Journals (Sweden)

    Peričin Draginja M.

    2007-01-01

    Full Text Available The feasibility of using pumpkin oil cake (PuOC, individual and in combination with wheat bran (WB, as substrate for the production of Exo-polygalacturonase (Exo-p by starter culture Penicillium roqueforti in solid state fermentation (SSF has been evaluated. The kinetics of enzyme production was investigated using PuOC alone in the range from 13 to 168 h, with moisture contents varying from 44% the ability to grow and produce Exo-p activity on this substrate, reaching a maximum value of 1451.75 U/g.d.w PuOC by the 5th day of fermentation. Fermentation experiments indicated that the water activity (aw influenced the enzyme production. A medium with aw 0.932 and the fermentation time of 5 days were selected, as these conditions resulted in the highest pectolytic activity and were used for further investigation. A next step in this research was to examine the effect of the substrate combination, PuOC with wheat bran (WB, in different ratios. The addition of WB as carbon sources was found to have a significant influence on the enzymes yields. Exo-p activities were the highest with initial water activity of a w 0.932 and PuOC supplementation with WB (1:0.67.

  16. Chandra High Resolution Spectroscopy of the Burst Spectrum of EXO 0748-67

    NARCIS (Netherlands)

    Telis, G.; Paerels, F.; Audard, M.; Lanz, T.; Cottam, J.; Méndez, R.M.; Bildsten, L.; Chang, P.; Marshall, H.

    2004-01-01

    We have observed EXO0748-67 for approximately 300 ksec with the High Energy Transmission Grating Spectrometer on Chandra. A total of 35 Type I X-ray bursts occurred during our observation, and from these we obtained a composite burst spectrum with high sensitivity in the Fe K band. Along with the sp

  17. Production, Purification of Exo-Polygalacturonase from Soil Isolate Paecilomyces variotii NFCCI 1769 and Its Application.

    Science.gov (United States)

    Patil, Nitinkumar P; Patil, Kanchankumar P; Chaudhari, Bhushan L; Chincholkar, Sudhir B

    2012-06-01

    The aim of the present study was to produce exo-polygalacturonase from potent soil isolate by submerged fermentation and its application for fruit juice treatment. Pectinase producing strains were selectively isolated from pectin industry waste. A selected isolate C2 was found to produce significant amount of exo-polygalacturonase. The isolate was identified as Paecilomyces variotii on the basis of morphological characteristics and 18S rRNA gene sequence analysis. The exo-polygalacturonase produced by the isolate was purified by ammonium sulphate precipitation, size exclusion chromatography and ion exchange chromatography. The purified enzyme had MW of 39.4 kD based on SDS PAGE. Under partially optimized conditions, purified exo-polygalacturonase showed specific activity of 98.49 U/mg protein at pH 6.0 and 30°C. The enzyme was comparatively stable from 10 to 30°C and the activity decreased with increasing temperature. Purified enzyme brought about considerable reduction in viscosity of fruit juice samples.

  18. Simultaneous Production of Amyloglucosidase and Exo-Polygalacturonase by Aspergillus niger in a Rotating Drum Reactor.

    Science.gov (United States)

    Colla, Eliane; Santos, Lucielen Oliveira; Deamici, Kricelle; Magagnin, Glênio; Vendruscolo, Mauricio; Costa, Jorge Alberto Vieira

    2017-02-01

    Simultaneous production of amyloglucosidase (AMG) and exo-polygalacturonase (exo-PG) was carried out by Aspergillus niger in substrate of defatted rice bran in a rotating drum bioreactor (RDB) and studied by a 3(1) × 2(2) factorial experimental design. Variables under study were A. niger strains (A. niger NRRL 3122 and A. niger t0005/007-2), types of inoculum (spore suspension and fermented bran), and types of inducer (starch, pectin, and a mix of both). Solid-state fermentation process (SSF) was conducted at 30 °C under 60-vvm aeration for 96 h in a pilot scale. Production of AMG and exo-PG was significantly affected by the fungal strain and the type of inoculum, but inducers did not trigger any significant effect, an evidence of the fact that these enzymes are constitutive. The maximum activity of exo-PG was 84 U gdm(-1) whereas the maximum yield of AMG was 886.25 U gdm(-1).

  19. Russian contribution to the ExoMars project

    Science.gov (United States)

    Zelenyi, L.; Korablev, O.; Rodionov, D.; Khartov, V.; Martynov, M.; Lukyanchikov, A.

    2014-04-01

    The ExoMars ESA-led mission is dedicated to study of Mars and in particular its habitability. It consists of two launches, one planned in 2016 to deliver to Mars a telecommunication and science orbiter Trace Gas Orbiter (TGO) and a demonstrator of entry into the atmosphere and landing on the Mars surface, Entry, Descent and Landing Demonstrator Module (EDM). In 2018 a rover with drilling capability will be delivered to the surface of Mars. Since 2012 this mission, previously planned in cooperation with NASA is being developed in cooperation with Roscosmos. Both launches are planned with Proton-Breeze. In 2016 Russia contributes a significant part of the TGO science payload. In 2018 the landing will be provided by a joint effort capitalizing on the EDM technology. Russia contributes few science instruments for the rover, and leads the development of a long-living geophysical platform on the surface of Mars. Russian science instruments for TGO, the Atmospheric Chemistry Suite (ACS) and the Fine Resolution Epithermal Neutrons Detector (FREND) constituent a half of its scientific payload, European instrument being NOMAD for mapping and detection of trace species, and CASSIS camera for high-resolution mapping of target areas. The ACS package consists of three spectrometers covering spectral range from 0.7 to 17 μm with spectral resolving power reaching 50000. It is dedicated to studies of the composition of the Martian atmosphere and the Martian climate. FREND is a neutron detector with a collimation module, which significantly narrows the field of view of the instrument, allowing to create higher resolution maps of hydrogen-abundant regions on Mars. The spatial resolution of FREND will be ~40 km from the 400- km TGO orbit that is ~10 times better than HEND on Mars-Odyssey. Additionally, FREND includes a dosimeter module for monitoring radiation levels in orbit around Mars. In the 2018 mission, Russia takes the major responsibility of the descent module. The primary

  20. Measurement of the Drift Velocity and Transverse Diffusion of Electrons in Liquid Xenon with the EXO-200 Detector

    CERN Document Server

    :,; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Cen, W R; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Daughhetee, J; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feyzbakhsh, S; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Hughes, M; Jewell, M J; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krucken, R; Kuchenkov, A; Kumar, K S; Lan, Y; Leonard, D S; Licciardi, C; Lin, Y H; MacLellan, R; Marino, M G; Mong, B; Moore, D; Njoya, O; Nelson, R; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retiere, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya; Zettlemoyer, J

    2016-01-01

    The EXO-200 Collaboration is searching for neutrinoless double beta decay using a liquid xenon (LXe) time projection chamber. This measurement relies on modeling the transport of charge deposits produced by interactions in the LXe to allow discrimination between signal and background events. Here we present measurements of the transverse diffusion constant and drift velocity of electrons at drift fields between 20~V/cm and 615~V/cm using EXO-200 data. At the operating field of 380~V/cm EXO-200 measures a drift velocity of 1.705$_{-0.010}^{+0.014}$~mm/$\\mu$s and a transverse diffusion coefficient of 55$\\pm$4~cm$^2$/s.

  1. Kuiper Binary Object Formation

    CERN Document Server

    Nazzario, R C; Covington, C; Kagan, D; Hyde, T W

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction between the KBOs and the third body causes one of four effects; scattering into the Oort cloud, collisions with the growing protoplanets, formation of binary pairs, or creation of a single Kuiper belt object. Additionally, the initial location of the progenitors of the Kuiper belt objects also has a significant effect on binary formation.

  2. Kuiper Binary Object Formation

    OpenAIRE

    Nazzario, R. C.; Orr, K.; Covington, C.; Kagan, D.; Hyde, T. W.

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction betw...

  3. Exo-Transmit: An Open-Source Code for Calculating Transmission Spectra for Exoplanet Atmospheres of Varied Composition

    Science.gov (United States)

    Kempton, Eliza M.-R.; Lupu, Roxana; Owusu-Asare, Albert; Slough, Patrick; Cale, Bryson

    2017-04-01

    We present Exo-Transmit, a software package to calculate exoplanet transmission spectra for planets of varied composition. The code is designed to generate spectra of planets with a wide range of atmospheric composition, temperature, surface gravity, and size, and is therefore applicable to exoplanets ranging in mass and size from hot Jupiters down to rocky super-Earths. Spectra can be generated with or without clouds or hazes with options to (1) include an optically thick cloud deck at a user-specified atmospheric pressure or (2) to augment the nominal Rayleigh scattering by a user-specified factor. The Exo-Transmit code is written in C and is extremely easy to use. Typically the user will only need to edit parameters in a single user input file in order to run the code for a planet of their choosing. Exo-Transmit is available publicly on Github with open-source licensing at https://github.com/elizakempton/Exo_Transmit.

  4. Exo-Transmit: An Open-Source Code for Calculating Transmission Spectra for Exoplanet Atmospheres of Varied Composition

    CERN Document Server

    Kempton, Eliza M -R; Owusu-Asare, Albert; Slough, Patrick; Cale, Bryson

    2016-01-01

    We present Exo-Transmit, a software package to calculate exoplanet transmission spectra for planets of varied composition. The code is designed to generate spectra of planets with a wide range of atmospheric composition, temperature, surface gravity, and size, and is therefore applicable to exoplanets ranging in mass and size from hot Jupiters down to rocky super-Earths. Spectra can be generated with or without clouds or hazes with options to (1) include an optically thick cloud deck at a user-specified atmospheric pressure or (2) to augment the nominal Rayleigh scattering by a user-specified factor. The Exo-Transmit code is written in C and is extremely easy to use. Typically the user will only need to edit parameters in a single user input file in order to run the code for a planet of their choosing. Exo-Transmit is available publicly on Github with open-source licensing at https://github.com/elizakempton/Exo_Transmit .

  5. "Where On Mars?": A Web Map Visualisation of the ExoMars 2018 Rover Candidate Landing Sites

    Science.gov (United States)

    Manaud, N.; Boix, O.; Vago, J.; Hill, A.; Iriberri, C.; Carrión, D.

    2015-10-01

    The ExoMars 2018 mission will deliver a European rover and a Russian surface platform to the surface of Mars. Armed with a drill that can bore 2 metres into rock, the ExoMars rover will travel across the Martian surface to search for signs of life, past or present. But where on Mars to land? - The search for a suitable ExoMars rover landing site began in December 2013, when the planetary science community was asked to propose candidates. Eight proposals were considered during a workshop held by the ExoMars Landing Site Selection Working Group (LSSWG). By the end of the workshop, there were four clear front-runners. Following additional review, the four sites have now been formally recommended for further detailed analysis [1]: Mawrth Vallis, Oxia Planum, Hypanis Vallis and Aram Dorsum. Scientists will continue working on the characterisation of these four sites until they provide their final recommendation in October 2017.

  6. Eclipsing Binary Pulsars

    CERN Document Server

    Freire, P C C

    2004-01-01

    The first eclipsing binary pulsar, PSR B1957+20, was discovered in 1987. Since then, 13 other eclipsing low-mass binary pulsars have been found, 12 of these are in globular clusters. In this paper we list the known eclipsing binary pulsars and their properties, with special attention to the eclipsing systems in 47 Tuc. We find that there are two fundamentally different groups of eclipsing binary pulsars; separated by their companion masses. The less massive systems (M_c ~ 0.02 M_sun) are a product of predictable stellar evolution in binary pulsars. The systems with more massive companions (M_c ~ 0.2 M_sun) were formed by exchange encounters in globular clusters, and for that reason are exclusive to those environments. This class of systems can be used to learn about the neutron star recycling fraction in the globular clusters actively forming pulsars. We suggest that most of these binary systems are undetectable at radio wavelengths.

  7. Four promoters subject to regulation by ExoR and PhoB direct transcription of the Sinorhizobium melilotiexoYFQ operon involved in the biosynthesis of succinoglycan.

    Science.gov (United States)

    Quester, Ingmar; Becker, Anke

    2004-01-01

    Succinoglycan (EPS I), the main acidic exopolysaccharide of Sinorhizobium meliloti, is required for the initiation and elongation of infection threads during nodulation of the host plant alfalfa. The gene products of the exoYFQ operon are involved in the first step of succinoglycan biosynthesis as well as in the polymerisation of subunits to the high-molecular-mass form of this exopolysaccharide. One promoter region that directs transcription of exoX and two promoter regions that drive transcription of exoY were mapped in the exoX-exoY intergenic region. The distal exoY promoter region containing three putative -10 promoter elements was active under standard growth conditions and was subject to ExoR-dependent regulation. Although this promoter region was stimulated in a phoB mutant, no PHO box-like sequences were found, suggesting an indirect regulatory effect of PhoB. The proximal promoter contains a PHO box-like sequence in the putative -35 region and was affected by low and high phosphate concentrations dependent on PhoB. In the case of deleted upstream regions, this promoter was also controlled by ExoR. An additional promoter displaying activity in exoR, mucR and phoB mutants under standard conditions was identified upstream of exoF. The putative -35 promoter element of this promoter is covered by a second PHO box-like sequence.

  8. ExoU activates NF-κB and increases IL-8/KC secretion during Pseudomonas aeruginosa infection.

    Directory of Open Access Journals (Sweden)

    Carolina Diettrich Mallet de Lima

    Full Text Available ExoU, a Pseudomonas aeruginosa cytotoxin injected into host cytosol by type III secretion system, exhibits a potent proinflammatory activity that leads to a marked recruitment of neutrophils to infected tissues. To evaluate the mechanisms that account for neutrophil infiltration, we investigated the effect of ExoU on IL-8 secretion and NF-κB activation. We demonstrate that ExoU increases IL-8 mRNA and protein levels in P. aeruginosa-infected epithelial and endothelial cell lines. Also, ExoU induces the nuclear translocation of p65/p50 NF-κB transactivator heterodimer as well as NF-κB-dependent transcriptional activity. ChIP assays clearly revealed that ExoU promotes p65 binding to NF-κB site in IL-8 promoter and the treatment of cultures with the NF-κB inhibitor Bay 11-7082 led to a significant reduction in IL-8 mRNA levels and protein secretion induced by ExoU. These results were corroborated in a murine model of pneumonia that revealed a significant reduction in KC secretion and neutrophil infiltration in bronchoalveolar lavage when mice were treated with Bay 11-7082 before infection with an ExoU-producing strain. In conclusion, our data demonstrate that ExoU activates NF-κB, stimulating IL-8 expression and secretion during P. aeruginosa infection, and unveils a new mechanism triggered by this important virulence factor to interfere in host signaling pathways.

  9. Pseudolipasin A is a specific inhibitor for phospholipase A2 activity of Pseudomonas aeruginosa cytotoxin ExoU.

    Science.gov (United States)

    Lee, Vincent T; Pukatzki, Stefan; Sato, Hiromi; Kikawada, Eriya; Kazimirova, Anastasia A; Huang, Jin; Li, Xiaohua; Arm, Jonathan P; Frank, Dara W; Lory, Stephen

    2007-03-01

    A number of bacterial pathogens utilize the type III secretion pathway to deliver effector proteins directly into the host cell cytoplasm. Certain strains of Pseudomonas aeruginosa associated with acute infections express a potent cytotoxin, exoenzyme U (ExoU), that is delivered via the type III secretion pathway directly into contacting host cells. Once inside the mammalian cell, ExoU rapidly lyses the intoxicated cells via its phospholipase A(2) (PLA(2)) activity. A high-throughput cell-based assay was developed to screen libraries of compounds for those capable of protecting cells against the cytotoxic effects of ExoU. A number of compounds were identified in this screen, including one group that blocks the intracellular activity of ExoU. In addition, these compounds specifically inhibited the PLA(2) activity of ExoU in vitro, whereas eukaryotic secreted PLA(2) and cytosolic PLA(2) were not inhibited. This novel inhibitor of ExoU-specific PLA(2) activity, named pseudolipasin A, may provide a new lead for virulence factor-based therapeutic design.

  10. EXO1 is critical for embryogenesis and the DNA damage response in mice with a hypomorphic Nbs1 allele

    Science.gov (United States)

    Rein, Katrin; Yanez, Diana A.; Terré, Berta; Palenzuela, Lluís; Aivio, Suvi; Wei, Kaichun; Edelmann, Winfried; Stark, Jeremy M.; Stracker, Travis H.

    2015-01-01

    The maintenance of genome stability is critical for the suppression of diverse human pathologies that include developmental disorders, premature aging, infertility and predisposition to cancer. The DNA damage response (DDR) orchestrates the appropriate cellular responses following the detection of lesions to prevent genomic instability. The MRE11 complex is a sensor of DNA double strand breaks (DSBs) and plays key roles in multiple aspects of the DDR, including DNA end resection that is critical for signaling and DNA repair. The MRE11 complex has been shown to function both upstream and in concert with the 5′-3′ exonuclease EXO1 in DNA resection, but it remains unclear to what extent EXO1 influences DSB responses independently of the MRE11 complex. Here we examine the genetic relationship of the MRE11 complex and EXO1 during mammalian development and in response to DNA damage. Deletion of Exo1 in mice expressing a hypomorphic allele of Nbs1 leads to severe developmental impairment, embryonic death and chromosomal instability. While EXO1 plays a minimal role in normal cells, its loss strongly influences DNA replication, DNA repair, checkpoint signaling and damage sensitivity in NBS1 hypomorphic cells. Collectively, our results establish a key role for EXO1 in modulating the severity of hypomorphic MRE11 complex mutations. PMID:26160886

  11. The DREAMS experiment on-board the Schiaparelli lander of ExoMars mission

    Science.gov (United States)

    Esposito, F.

    2015-10-01

    The DREAMS package is a suite of sensors for the characterization of the Martian basic state meteorology and of the atmospheric electric properties at the landing site of the Entry, descent and landing Demonstration Module (EDM) of the ExoMars mission. The EDM will land on Meridiani Planum in October 2016, during the statistical dust storm season. This will allow DREAMS to investigate the status of the atmosphere of Mars during this particular season and also to understand the role of dust as a potential source of electrical phenomena on Mars. DREAMS will be the first instrument to perform a measurement of electric field on Mars. DREAMS FM has been completely developed and tested and it has been delivered to ESA for integration on the Schiaparelli lander of the ExoMars 2016 mission. Launch is foreseen for January 2016.

  12. Identification and Analysis of Landing sites for the ESA ExoMars Rover (2018)

    Science.gov (United States)

    Balme, Matthew; Bridges, John; Fawdon, Peter; Grindrod, Peter; Gupta, Sanjeev; Michalski, Joe; Conway, Susan

    2014-05-01

    The exploration and search for life on Mars forms a cornerstone of international solar system exploration. In 2018, the European Space agency will launch the ExoMars Rover and Lander to further this exploration. The key science objectives of the ExoMars Rover are to: 1) search for signs of past and present life on Mars; 2) investigate the water/geochemical environment as a function of depth in the shallow subsurface; and 3) to characterise the surface environment. To meet these objectives ExoMars will drill into the sub-surface to look for indicators of past life using a range of complementary techniques, including assessment of morphology (potential fossil organisms), mineralogy (past environments) and a search for organic molecules and their chirality (biomarkers). The choice of landing site is vital if ExoMars' scientific objectives are to be met. The landing site must: (i) be ancient (≥3.6 Ga); (ii) show abundant morphological and mineral evidence for long-term, or frequently reoccurring, aqueous activity; (iii) include numerous sedimentary outcrops that (iv) are distributed over the landing region (the typical Rover traverse range is only a few km, but the uncertainty in the location of the landing site forms an elliptical of size ~ 100 by 15 km); and (v) have little dust coverage. In addition, in order to land and operate safely, various 'engineering constraints' apply, including: (i) latitude limited to 5º S to 25º N; (ii) maximum altitude of the landing site 2 km below Mars's datum, (iii) few steep slopes within the uncertainty ellipse. These constraints are onerous. In particular, the objective to drill into sediments, the requirement for distributed targets within the ellipse, and the ellipse size, make ExoMars site selection extremely challenging. To meet these challenges, we have begun an intensive study of the martian landscape to identify as many possible ExoMars landing sites as possible. We have converted the current engineering constraints into

  13. Lower Limits on Aperture Size for an ExoEarth-Detecting Coronagraphic Mission

    CERN Document Server

    Stark, Christopher C; Mandell, Avi; Clampin, Mark; Domagal-Goldman, Shawn D; McElwain, Michael W; Stapelfeldt, Karl R

    2015-01-01

    The yield of Earth-like planets will likely be a primary science metric for future space-based missions that will drive telescope aperture size. Maximizing the exoEarth candidate yield is therefore critical to minimizing the required aperture. Here we describe a method for exoEarth candidate yield maximization that simultaneously optimizes, for the first time, the targets chosen for observation, the number of visits to each target, the delay time between visits, and the exposure time of every observation. This code calculates both the detection time and multi-wavelength spectral characterization time required for planets. We also refine the astrophysical assumptions used as inputs to these calculations, relying on published estimates of planetary occurrence rates as well as theoretical and observational constraints on terrestrial planet sizes and classical habitable zones. Given these astrophysical assumptions, optimistic telescope and instrument assumptions, and our new completeness code that produces the hi...

  14. The ExoMol database: molecular line lists for exoplanet and other hot atmospheres

    CERN Document Server

    Tennyson, Jonathan; Al-Refaie, Ahmed F; Barton, Emma J; Chubb, Katy L; Coles, Phillip A; Diamantopoulou, S; Gorman, Maire N; Hill, Christian; Lam, Aden Z; Lodi, Lorenzo; McKemmish, Laura K; Na, Yueqi; Owens, Alec; Polyansky, Oleg L; Sousa-Silva, Clara; Underwood, Daniel S; Yachmenev, Andrey; Zak, Emil

    2016-01-01

    The ExoMol database (www.exomol.com) provides extensive line lists of molecular transitions which are valid over extended temperatures ranges. The status of the current release of the database is reviewed and a new data structure is specified. This structure augments the provision of energy levels (and hence transition frequencies) and Einstein $A$ coefficients with other key properties, including lifetimes of individual states, temperature-dependent cooling functions, Land\\'e $g$-factors, partition functions, cross sections, $k$-coefficients and transition dipoles with phase relations. Particular attention is paid to the treatment of pressure broadening parameters. The new data structure includes a definition file which provides the necessary information for utilities accessing ExoMol through its application programming interface (API). Prospects for the inclusion of new species into the database are discussed.

  15. Barium Tagging in Liquid Xenon for the nEXO Experiment

    Science.gov (United States)

    Kravitz, Scott; nEXO Collaboration

    2016-09-01

    nEXO is a next-generation experiment designed to search for neutrinoless double beta decay of xenon-136 in a liquid xenon time projection chamber. Positive observation of this decay would determine the neutrino to be a MAJORANA particle, as well as measure the absolute neutrino mass scale. In order to greatly reduce background contributions to this search, the collaboration is developing several ``barium tagging'' techniques to recover and identify the decay daughter, barium-136. Barium tagging may be available for a second phase of nEXO operation, allowing for neutrino mass sensitivity beyond the inverted mass hierarchy. Tagging methods for this phase include barium-ion capture on a probe with identification by resonance ionization laser spectroscopy. Inclusion of an argon ion gun in this system allows for improved cleaning and preparation of the barium deposition substrate, with recent results reported in this presentation.

  16. Spectroscopy of Ba and Ba$^+$ deposits in solid xenon for barium tagging in nEXO

    OpenAIRE

    Mong, B.; Cook, S; Walton, T.; Chambers, C.; Craycraft, A.; Benitez-Medina, C.; Hall, K.; Fairbank Jr., W.; Albert, J. B.; Auty, D. J.; Barbeau, P. S.; Basque, V.; Beck, D.; Breidenbach, M.; Brunner, T.

    2014-01-01

    Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra for deposits of barium atoms and ions in solid xenon matrices are presented. Excitation spectra for prominent emission lines, temperature dependence and bleaching of the fluorescence reveal the existence of different matrix sites. A regular series of sharp lines observed in Ba$^+$ deposits is identified with some type of barium hydride molecule. Lower limits for the fl...

  17. Unconventional exo selectivity in thermal normal-electron-demand Diels–Alder reactions

    Science.gov (United States)

    Ho, Guo-Ming; Huang, Ci-Jhang; Li, Elise Yu-Tzu; Hsu, Sheng-Kai; Wu, Ti; Zulueta, Medel Manuel L.; Wu, Kevin Binchia; Hung, Shang-Cheng

    2016-10-01

    The Diels–Alder reaction is a useful tool for generating functionalized chiral molecules through the concerted cycloaddition of dienes and dienophiles leading to six-membered rings. Traditionally, the selective predictions of the products rely heavily on consideration of the secondary orbital interactions that stabilize the endo pathway. However, there remain some basic examples defying this notion and produce the exo-isomer as major product. Here we systematically evaluated of the structural features driving exo selectivity in thermal normal-electron-demand Diels–Alder reactions. Substitution at the Cβ position and the size and electronegativity of the electron-withdrawing group of the dienophile are contributing factors. Experimental and computational studies both point toward the steric and electrostatic forces between the substituents in both the diene and the dienophile that increase the likelihood of the exo pathway. For these substrates, the dominance of the endo pathway is reduced by transition state distortions and poor structural alignments of the reacting partners. We also noted the tilt of the dienophile with respect to the diene causing steric strain on the functionalities at the more advanced bond forming carbon-carbon position of the endo transition state. Insights into such factors may benefit synthetic planning and asserting control over this important named reaction.

  18. Mars Organic Molecule Analyzer (MOMA) mass spectrometer for ExoMars 2018 and beyond

    Science.gov (United States)

    Brinckerhoff, W. B.; Pinnick, V. T.; van Amerom, F. H. W.; Danell, R. M.; Arevalo, R. D.; Atanassova, M. S.; Li, Xiang; Mahaffy, P. R.; Cotter, R. J.; Goesmann, F.; Steininger, H.

    The 2018 joint ESA-Roscosmos ExoMars rover mission will seek the signs of past or present life in the near-surface environment of Mars. The rover will obtain samples from as deep as two meters beneath the surface and deliver them to an onboard analytical laboratory for detailed examination. The Mars Organic Molecule Analyzer (MOMA) investigation forms a core part of the sample analysis capability of ExoMars. Its top objective is to address the main “ life signs” goal of the mission through detailed chemical analysis of the acquired samples. MOMA characterizes organic compounds in the samples with a novel dual ion source ion trap mass spectrometer (ITMS). The ITMS supports both pyrolysis-gas chromatography (pyr-GC) and Mars ambient laser desorption/ionization (LDI) analyses in an extremely compact package. Combined with the unprecedented depth sampling capability of ExoMars, MOMA affords a broad and powerful search for organics over a range of preservational environments, volatility, and molecular weight.

  19. Exo+ proofreading polymerases mediate genetic analysis and its application in biomedical studies

    Institute of Scientific and Technical Information of China (English)

    Duan-fang LIAO; Lin-ling CHEN; Cui-ying PENG; Jia ZHANG; Kai LI

    2005-01-01

    Polymerases with a proofreading function in their internal 3' to 5' exonuclease possess high fidelity for DNA replication both in vivo and in vitro. The obstacle facing Exo+ polymerases for single nucleotide polymorphism (SNP) detection could be bypassed by using primer-3'-termini modification. This hypothesis has been well tested using three types of modified allele specific primers with: 3' labeling, 3'to 5'exonuclease resistance, and 3'dehydroxylation. Accordingly, three new SNP assaying methods have been developed to carry out genome-wide genotyping,taking advantage of the enzymatic properties of Exo+ polymerases. These new mutation detection assays are widely adaptable to a variety of platforms, including multi-well plate and microarray technologies. Application of Exo+ polymerases to genetic analysis, including genotyping that is mostly relevant to pharmacogenetics, high-fidelity gene expression profiling, rare mutation detection and mutation load assay, will help to accelerate the pace of personalized medicine. In this review paper, we will first introduce three new assays that we have recently developed, and then describe a number of their applications in pharmacogenetics and in other biomedical studies.

  20. Hydrogen delivery onto white dwarfs from remnant exo-Oort cloud comets

    CERN Document Server

    Veras, Dimitri; Gaensicke, Boris T

    2014-01-01

    The origin of trace hydrogen in white dwarfs (WDs) with He-dominated atmospheres is a long-standing problem, one that cannot satisfactorily be explained by the historically-favoured hypothesis of accretion from the interstellar medium. Here we explore the possibility that the gradual accretion of exo-Oort cloud comets, which are a rich source of H, contributes to the apparent increase of trace H with WD cooling age. We determine how often remnant exo-Oort clouds, freshly excited from post-main-sequence stellar mass loss, dynamically inject comets inside the WD's Roche radius. We improve upon previous studies by considering a representative range of single WD masses (0.52-1.00 Solar masses) and incorporating different cloud architectures, giant branch stellar mass loss, stellar flybys, Galactic tides and a realistic escape ellipsoid in self-consistent numerical simulations that integrate beyond 8 Gyr ages of WD cooling. We find that about 10^{-5} of the material in an exo-Oort cloud is typically amassed onto t...

  1. Binary Masking & Speech Intelligibility

    DEFF Research Database (Denmark)

    Boldt, Jesper

    The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime...... mask using a directional system and a method for correcting errors in the target binary mask. The last part of the thesis, proposes a new method for objective evaluation of speech intelligibility.......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...

  2. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  3. Binary Neutron Star Mergers

    Directory of Open Access Journals (Sweden)

    Joshua A. Faber

    2012-07-01

    Full Text Available We review the current status of studies of the coalescence of binary neutron star systems. We begin with a discussion of the formation channels of merging binaries and we discuss the most recent theoretical predictions for merger rates. Next, we turn to the quasi-equilibrium formalisms that are used to study binaries prior to the merger phase and to generate initial data for fully dynamical simulations. The quasi-equilibrium approximation has played a key role in developing our understanding of the physics of binary coalescence and, in particular, of the orbital instability processes that can drive binaries to merger at the end of their lifetimes. We then turn to the numerical techniques used in dynamical simulations, including relativistic formalisms, (magneto-hydrodynamics, gravitational-wave extraction techniques, and nuclear microphysics treatments. This is followed by a summary of the simulations performed across the field to date, including the most recent results from both fully relativistic and microphysically detailed simulations. Finally, we discuss the likely directions for the field as we transition from the first to the second generation of gravitational-wave interferometers and while supercomputers reach the petascale frontier.

  4. Binary and Millisecond Pulsars

    Directory of Open Access Journals (Sweden)

    Lorimer Duncan R.

    2008-11-01

    Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M_⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44 orbit around an unevolved companion.

  5. Binary Popldation Synthcsis Study

    Institute of Scientific and Technical Information of China (English)

    HAN Zhanwen

    2011-01-01

    Binary population synthesis (BPS), an approach to evolving millions of stars (including binaries) simultaneously, plays a crucial role in our understanding of stellar physics, the structure and evolution of galaxies, and cosmology. We proposed and developed a BPS approach, and used it to investigate the formation of many peculiar stars such as hot subdwarf stars, progenitors of type la supernovae, barium stars, CH stars, planetary nebulae, double white dwarfs, blue stragglers, contact binaries, etc. We also established an evolution population synthesis (EPS) model, the Yunnan Model, which takes into account binary interactions for the first time. We applied our model for the origin of hot subdwarf stars in the study of elliptical galaxies and explained their far-UV radiation.

  6. Eclipsing Binary Update, No. 2.

    Science.gov (United States)

    Williams, D. B.

    1996-01-01

    Contents: 1. Wrong again! The elusive period of DHK 41. 2. Stars observed and not observed. 3. Eclipsing binary chart information. 4. Eclipsing binary news and notes. 5. A note on SS Arietis. 6. Featured star: TX Ursae Majoris.

  7. Revealing Exo-Zody and Exo-Planets from Solar System Dust Measurements: ALADDIN-2 for the Solar Power Sail Mission

    Science.gov (United States)

    Yano, Hajime; Hirai, Takayuki

    2016-07-01

    The dust structure of our Solar System provides a benchmark information of dust disks of other exo-planetary systems in general, just like the Sun as the closest main sequence G-star that we can study with the most details. Heliocentric dust distributions and gravitational and orbital interactions with planets such as mean motion resonances (MMRs) of dust flux of our Solar System are what we can transfer the knowledge of our Solar System dust apply to infer anisotropic exo-zodiacal brightness, or spatial structures within a exo-planetary dust disks with information about potentially embedded planets inside. In the coming era of disk resolved observations by ALMA, TMT and other new telescopes, we will be able to apply what we find in the Solar System to the rest of planetary systems. In 2010-11, the IKAROS solar sail spacecraft carried the ALADDIN large area dust detector array to study large meteoroids between the Earth and Venus orbits. Yano et al. directly detected both the Earth's and Venus' MMRs dust structures, being consistent with numerical simulations that predict the existence of such local enhancements of dust distribution around these terrestrial planets, as well as Neptune. JAXA's Solar Power Sail mission plans to carry even larger dust detector inherited the technology onboard IKAROS, namely ALADDIN-2 in order to search for such MMRs in the Mars and Jupiter orbits, as predicted by Kuchner et al.(2000), in addition to make a continuous measurement of large dust flux from 1.0 to 5.2 AU crossing the main asteroid belt up to Jupiter Trojan region. It is also noted that recent reanalysis of the Pioneer 10 and 11 photo polarimeter data suggests a small enhancement of the brightness towards the anti-solar direction near Jupiter the largest planet of our Solar System, implying a possible existence of a dust belt related to the planet. The spatial density of dust particles directly measured by the ALADDIN-2 will provide a more conclusive and direct proof due to

  8. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter

    2008-01-01

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  9. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Rune Hansen, Esben; Srinivasa Rao, S.; Tiedemann, Peter

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  10. Orbits for sixteen binaries

    Directory of Open Access Journals (Sweden)

    Cvetković Z.

    2006-01-01

    Full Text Available In this paper orbits for 13 binaries are recalculated and presented. The reason is that recent observations show higher residuals than the corresponding ephemerides calculated by using the orbital elements given in the Sixth Catalog of Orbits of Visual Binary Stars. The binaries studied were: WDS 00182+7257 = A 803, WDS 00335+4006 = HO 3, WDS 00583+2124 = BU 302, WDS 01011+6022 = A 926, WDS 01014+1155 = BU 867, WDS 01112+4113 = A 655, WDS 01361−2954 + HJ 3447, WDS 02333+5219 = STT 42 AB,WDS 04362+0814 = A 1840 AB,WDS 08017−0836 = A 1580, WDS 08277−0425 = A 550, WDS 17471+1742 = STF 2215 and WDS 18025+4414 = BU 1127 Aa-B. In addition, for three binaries - WDS 01532+1526 = BU 260, WDS 02563+7253 = STF 312 AB and WDS 05003+3924 = STT 92 AB - the orbital elements are calculated for the first time. In this paper the authors present not only the orbital elements, but the masses dynamical parallaxes, absolute magnitudes and ephemerides for the next five years, as well.

  11. Equational binary decision diagrams

    NARCIS (Netherlands)

    Groote, J.F.; Pol, J.C. van de

    2000-01-01

    We incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and tautology checkin

  12. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  13. Learning to assign binary weights to binary descriptor

    Science.gov (United States)

    Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

    2016-10-01

    Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

  14. The Use of ExoSeal Vascular Closure Device for Direct Antegrade Superficial Femoral Artery Puncture Site Hemostasis

    Energy Technology Data Exchange (ETDEWEB)

    Rimon, Uri, E-mail: rimonu@sheba.health.gov.il; Khaitovich, Boris, E-mail: borislena@012.net.il [Tel-Aviv University, Diagnostic and Interventional Imaging Department, Chaim Sheba Medical Center, Tel-Hashomer, Affiliated to the Sackler School of Medicine (Israel); Yakubovich, Dmitry, E-mail: Dmitry.Yakubovitch@sheba.health.gov.il [Tel-Aviv University, Vascular Surgery Department, Chaim Sheba Medical Center, Tel-Hashomer, Affiliated to the Sackler School of Medicine (Israel); Bensaid, Paul, E-mail: paulbensaid@hotmail.com; Golan, Gil, E-mail: gilgolan201@gmail.com [Tel-Aviv University, Diagnostic and Interventional Imaging Department, Chaim Sheba Medical Center, Tel-Hashomer, Affiliated to the Sackler School of Medicine (Israel); Silverberg, Daniel, E-mail: Daniel.Silverberg@sheba.health.gov.il [Tel-Aviv University, Vascular Surgery Department, Chaim Sheba Medical Center, Tel-Hashomer, Affiliated to the Sackler School of Medicine (Israel)

    2015-06-15

    PurposeThis study was designed to assess the efficacy and safety of the ExoSeal vascular closure device (VCD) to achieve hemostasis in antegrade access of the superficial femoral artery (SFA).MethodsWe retrospectively reviewed the outcome of ExoSeal VCD used for hemostasis in 110 accesses to the SFA in 93 patients between July 2011 and July 2013. All patients had patent proximal SFA based on computer tomography angiography or ultrasound duplex. Arterial calcifications at puncture site were graded using fluoroscopy. The SFA was accessed in an antegrade fashion with ultrasound or fluoroscopic guidance. In all patients, 5–7F vascular sheaths were used. The ExoSeal VCD was applied to achieve hemostasis at the end of the procedure. All patients were clinically examined and had ultrasound duplex exam for any puncture site complications during the 24 h postprocedure.ResultsIn all procedures, the ExoSeal was applied successfully. We did not encounter any device-related technical failure. There were four major complications in four patients (3.6 %): three pseudoaneurysms, which were treated with direct thrombin injection, and one hematoma, which necessitated transfusion of two blood units. All patients with complications were treated with anticoagulation preprocedure or received thrombolytic therapy.ConclusionsThe ExoSeal VCD can be safely used for antegrade puncture of the SFA, with a high procedural success rate (100 %) and a low rate of access site complications (3.6 %)

  15. An Optimal Energy Estimator to Reduce Correlated Noise for the EXO-200 Light Readout

    CERN Document Server

    :,; Hall, C; Albert, J B; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Cen, W R; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Feyzbakhsh, S; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hughes, M; Jewell, M J; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Njoya, O; Nelson, R; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retière, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2016-01-01

    The energy resolution of the EXO-200 detector is limited by electronics noise in the measurement of the scintillation response. Here we present a new technique to extract optimal scintillation energy measurements for signals split across multiple channels in the presence of correlated noise. The implementation of these techniques improves the energy resolution of the detector at the neutrinoless double beta decay Q-value from $\\left[1.9641\\pm 0.0039\\right]\\%$ to $\\left[1.5820\\pm 0.0044\\right]\\%$.

  16. El artista como producto en Corea del Sur: EXO y el fenómeno fan.

    OpenAIRE

    HURTADO OLMOS, LORENA

    2016-01-01

    [EN] On the following Final Degree Project, there will be some research about the South Korean Pop Culture. The study will be based on its music industry, and it will analyze how it raises artists that become idols to the eyes of young people, creating a truly mass phenomena. To achieve this, an analysis of the K-Pop band EXO will be done, which success in the last years, has helped to popularize the genre, not only in Asia, but in most of Western countries. It will explain the commercial...

  17. First search for Lorentz and C P T violation in double beta decay with EXO-200

    Science.gov (United States)

    Albert, J. B.; Barbeau, P. S.; Beck, D.; Belov, V.; Breidenbach, M.; Brunner, T.; Burenkov, A.; Cao, G. F.; Chambers, C.; Cleveland, B.; Coon, M.; Craycraft, A.; Daniels, T.; Danilov, M.; Daugherty, S. J.; Davis, C. G.; Davis, J.; Delaquis, S.; Der Mesrobian-Kabakian, A.; DeVoe, R.; Díaz, J. S.; Didberidze, T.; Dilling, J.; Dolgolenko, A.; Dolinski, M. J.; Dunford, M.; Fairbank, W.; Farine, J.; Feyzbkhsh, S.; Feldmeier, W.; Fierlinger, P.; Fudenberg, D.; Gornea, R.; Graham, K.; Gratta, G.; Hall, C.; Homiller, S.; Hughes, M.; Jewell, M. J.; Jiang, X. S.; Johnson, A.; Johnson, T. N.; Johnston, S.; Karelin, A.; Kaufman, L. J.; Killick, R.; Koffas, T.; Kravitz, S.; Krücken, R.; Kuchenkov, A.; Kumar, K. S.; Leonard, D. S.; Licciardi, C.; Lin, Y. H.; Ling, J.; MacLellan, R.; Marino, M. G.; Mong, B.; Moore, D.; Nelson, R.; Njoya, O.; Odian, A.; Ostrovskiy, I.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Retiére, F.; Rowson, P. C.; Russell, J. J.; Schubert, A.; Sinclair, D.; Smith, E.; Stekhanov, V.; Tarka, M.; Tolba, T.; Tsang, R.; Twelker, K.; Vuilleumier, J.-L.; Vogel, P.; Waite, A.; Walton, J.; Walton, T.; Weber, M.; Wen, L. J.; Wichoski, U.; Wood, J.; Yang, L.; Yen, Y.-R.; Zeldovich, O. Ya.; EXO-200 Collaboration

    2016-04-01

    A search for Lorentz- and C P T -violating signals in the double beta decay spectrum of 136Xe has been performed using an exposure of 100 kg .yr with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz-violation was found, and a two-sided limit of -2.65 ×10-5 GeV SME). This is the first experimental study of the effect of the SME-defined oscillation-free and momentum-independent neutrino coupling operator on the double beta decay process.

  18. Synthesis of diversely 1,3,5-trisubstituted pyrazoles via 5-exo-dig cyclization.

    Science.gov (United States)

    Borkin, Dmitry A; Puscau, Mirela; Carlson, Alena; Solan, Agnes; Wheeler, Kraig A; Török, Béla; Dembinski, Roman

    2012-06-21

    5-Exo-dig cyclocondensation of alk-3-yn-1-ones with hydrazines, in the presence of montmorillonite K-10, provides an effective method with a high atom economy for the synthesis of diversely 1,3,5-trisubstituted pyrazoles. The microwave-accelerated reaction proceeds in the absence of solvent and leads to 5-benzyl substituted pyrazoles with good yields (72-91%). The regiochemistry of the process was confirmed by the X-ray crystallographic structure determination of 1-(2-fluorophenyl)-5-(4-methylbenzyl)-3-phenyl-1H-pyrazole.

  19. Modelling High Resolution Absorption Spectra with ExoMolLine Lists: NH3and CH4

    DEFF Research Database (Denmark)

    Barton, E. J.; Yurchenko, S. N.; Tennyson, J.;

    The conditions, chemical reactions and gas mixing in industrial progresses involving gasification or combustion can be monitored by in situ measurement of gas temperature and gas composition. This can be done spectroscopically, though the result is highly dependent on the quality of reference data...... [1]. For this reason, a smart collaboration has been established between Optical Diagnostics Group at DTU and ExoMol, to combine high resolution spectra measured at elevated temperatures and empirically tuned ab initio methods to produce suitable molecular line lists for modelling molecules...

  20. New Concept for Internal Heat Production in Hot Jupiter Exo-Planets

    CERN Document Server

    Herndon, J M

    2006-01-01

    Discovery of hot Jupiter exo-planets, those with anomalously inflated size and low density relative to Jupiter, has evoked much discussion as to possible sources of internal heat production. But to date, no explanations have come forth that are generally applicable. The explanations advanced typically involve presumed tidal dissipation and/or converted incident stellar radiation. The present, brief communication suggests a novel interfacial nuclear fission-fusion source of internal heat production for hot Jupiters that has been overlooked by theoreticians and which has potentially general applicability.

  1. The NOMAD Spectrometer Suite on ExoMars Trace Gas Orbiter: Calibration Results

    Science.gov (United States)

    Thomas, I. R.; Vandaele, A. C.; López-Moreno, J. J.; Patel, M. R.; Bellucci, G.; Drummond, R.; Neefs, E.; Rodriguez-Gómez, J.; Depiesse, C.; Mahieux, A.; Robert, S.; Daerden, F.

    2015-10-01

    NOMAD (Nadir and Occultation for MArs Discoveryis a suite of three high- resolution spectrometers on-board the ExoMars Trace Gas Orbiter. Observing in the ranges 200- 650nm and 2.2-4.3μm, the instrument will be able to detect and map a wide variety of Martian gases in unprecedented detail. The instrument was calibrated during March and April 2015; this presentation will describe the results of the tests performed and the expected performance when the instrument begins observing the planet in late 2017.

  2. Revisiting the stability of endo/exo Diels-Alder adducts between cyclopentadiene and 1,4-benzoquinone

    Energy Technology Data Exchange (ETDEWEB)

    Tormena, Claudio F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Lacerda Junior, Valdemar [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Oliveira, Kleber T. de [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas

    2010-07-01

    In this work it is presented a detailed theoretical analysis of the relative stability of endo/exo Diels-Alder adducts formed by the reaction between cyclopentadiene (1) and 1,4-benzoquinone (2). The intrinsic reaction coordinate (IRC) showed the existence of only one transition state for the reaction studied, for both endo 3 and exo 4 adducts. The energies of both adducts were obtained at high level of theory (CBS-Q) confirming that the endo adduct is more stable than exo, which is in the opposite way to the observed in reactions that usually follow Alder's rule. An electronic structure analysis was performed through NBO methodology, indicating that the attractive delocalization interaction predominates over the steric repulsive interaction in the endo adducts. In summary, for the studied cycloaddition reaction the endo adduct is the thermodynamic and kinetic product, which can be also confirmed by experimental data mentioned in this work. (author)

  3. Molecular Cloning, Expression Analysis and Localization of Exo70A1 Related to Self Incompatibility in Non-Heading Chinese Cabbage (Brassica campestrisssp. chinensis)

    Institute of Scientific and Technical Information of China (English)

    WANG Li; GE Ting-ting; PENG Hai-tao; WANG Cheng; LIU Tong-kun; HOU Xi-lin; LI Ying

    2013-01-01

    The exocyst is a conserved protein complex, and required for vesicles tethering, fusion and polarized exocytosis. Exo70A1, the exocyst subunit, is essential for assembly of the exocyst complex. To better understand potential roles of Exo70A1 in non-heading Chinese cabbage (Brassica campestrisssp. chinensis), we obtained the full-length cDNA ofExo70A1 gene, which consisted of 1917 bp and encoded a protein of 638 amino acids. BlastX showed BcExo70A1 shared 94.9% identity with Brassica oleraceavar. acephala (AEI26267.1), and clustered into a same group with other homologues inB. oleracea var. acephala andBrassica napus. Subcellular localization analysis showed BcExo70A1 was localized to punctate structures in cytosol of onion epithelial cells. Results showed that BcExo70A1 was widely presented in stamens, young stems, petals, unpollinated pistils, roots and leaves of self compatible and incompatible plants. The transcripts ofBcExo70A1 in non-heading Chinese cabbage declined during initial 1.5 h after incompatible pollination, while an opposite trend was presented after compatible pollination. Our study reveals that BcExo70A1 could play essential roles in plant growth and development, and is related to the rejection of self pollen in non-heading Chinese cabbage.

  4. The Binary Garrote

    CERN Document Server

    Kappen, H J

    2011-01-01

    In this paper, I present a new model and solution method for sparse regression. The model introduces binary selector variables $s_i$ for the features $i$ in a way that is similar to Breiman's Garrote model. I refer to this method as the binary Garrote (BG). The posterior probability for $s_i$ is computed in the variational approximation. The BG is compared numerically with the Lasso method and with ridge regression. Numerical results on synthetic data show that the BG yields more accurate predictions and more accurately reconstructs the true model than the other methods. The naive implementation of the BG requires the inversion of a modified covariance matrix which scales cubic in the number of features. We indicate how for sparse problem the solution can be computed linear in the number of features.

  5. Binary Tetrahedral Flavor Symmetry

    CERN Document Server

    Eby, David A

    2013-01-01

    A study of the T' Model and its variants utilizing Binary Tetrahedral Flavor Symmetry. We begin with a description of the historical context and motivations for this theory, together with some conceptual background for added clarity, and an account of our theory's inception in previous works. Our model endeavors to bridge two categories of particles, leptons and quarks, a unification made possible by the inclusion of additional Higgs particles, shared between the two fermion sectors and creating a single coherent system. This is achieved through the use of the Binary Tetrahedral symmetry group and an investigation of the Tribimaximal symmetry evidenced by neutrinos. Our work details perturbations and extensions of this T' Model as we apply our framework to neutrino mixing, quark mixing, unification, and dark matter. Where possible, we evaluate model predictions against experimental results and find excellent matching with the atmospheric and reactor neutrino mixing angles, an accurate prediction of the Cabibb...

  6. Binary Love Relations

    CERN Document Server

    Yagi, Kent

    2015-01-01

    When in a tight binary, the mutual tidal deformations of neutron stars imprint onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the gravitational wave model. We here resolve this problem by discovering approximately universal relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the gravitational wave model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between equation-of-state models, and improve tests of General Relativity and cosmology.

  7. Binary Love relations

    Science.gov (United States)

    Yagi, Kent; Yunes, Nicolás

    2016-07-01

    When in a tight binary, the mutual tidal deformations of neutron stars get imprinted onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave (GW) observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the GW model. We here resolve this problem by discovering approximately equation-of-state (EoS)-insensitive relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the GW model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between EoS models, and improve tests of general relativity and cosmology.

  8. The succinoglycan endoglycanase encoded by exoK is required for efficient symbiosis of Sinorhizobium meliloti 1021 with the host plants Medicago truncatula and Medicago sativa (Alfalfa).

    Science.gov (United States)

    Mendis, Hajeewaka C; Queiroux, Clothilde; Brewer, Tess E; Davis, Olivia M; Washburn, Brian K; Jones, Kathryn M

    2013-09-01

    The acidic polysaccharide succinoglycan produced by the nitrogen-fixing rhizobial symbiont Sinorhizobium meliloti 1021 is required for this bacterium to invade the host plant Medicago truncatula and to efficiently invade the host plant M. sativa (alfalfa). The β-glucanase enzyme encoded by exoK has previously been demonstrated to cleave succinoglycan and participate in producing the low molecular weight form of this polysaccharide. Here, we show that exoK is required for efficient S. meliloti invasion of both M. truncatula and alfalfa. Deletion mutants of exoK have a substantial reduction in symbiotic productivity on both of these plant hosts. Insertion mutants of exoK have an even less productive symbiosis than the deletion mutants with the host M. truncatula that is caused by a secondary effect of the insertion itself, and may be due to a polar effect on the expression of the downstream exoLAMON genes.

  9. 14-3-3 checkpoint regulatory proteins interact specifically with DNA repair protein human exonuclease 1 (hEXO1) via a semi-conserved motif

    DEFF Research Database (Denmark)

    Andersen, Sofie Dabros; Keijzers, Guido; Rampakakis, Emmanouil

    2012-01-01

    Human exonuclease 1 (hEXO1) acts directly in diverse DNA processing events, including replication, mismatch repair (MMR), and double strand break repair (DSBR), and it was also recently described to function as damage sensor and apoptosis inducer following DNA damage. In contrast, 14-3-3 proteins...... experiments reveal weak affinity of the more selective isoform 14-3-3s but both 14-3-3 isoforms ¿ and s significantly stimulate hEXO1 activity, indicating that these regulatory proteins exert a common regulation mode on hEXO1. Results demonstrate that binding involves the phosphorable amino acid S746 in hEXO1...... are specifically induced by replication inhibition leading to protein ubiquitination and degradation. We demonstrate direct and robust interaction between hEXO1 and six of the seven 14-3-3 isoforms in vitro, suggestive of a novel protein interaction network between DNA repair and cell cycle control. Binding...

  10. Binary-Signal Recovery

    Science.gov (United States)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  11. Massive Black Hole Binary Evolution

    Directory of Open Access Journals (Sweden)

    Merritt David

    2005-11-01

    Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

  12. Visual binary stars: data to investigate formation of binaries

    Science.gov (United States)

    Kovaleva,, D.; Malkov,, O.; Yungelson, L.; Chulkov, D.

    Statistics of orbital parameters of binary stars as well as statistics of their physical characteristics bear traces of star formation history. However, statistical investigations of binaries are complicated by incomplete or missing observational data and by a number of observational selection effects. Visual binaries are the most common type of observed binary stars, with the number of pairs exceeding 130 000. The most complete list of presently known visual binary stars was compiled by cross-matching objects and combining data of the three largest catalogues of visual binaries. This list was supplemented by the data on parallaxes, multicolor photometry, and spectral characteristics taken from other catalogues. This allowed us to compensate partly for the lack of observational data for these objects. The combined data allowed us to check the validity of observational values and to investigate statistics of the orbital and physical parameters of visual binaries. Corrections for incompleteness of observational data are discussed. The datasets obtained, together with modern distributions of binary parameters, will be used to reconstruct the initial distributions and parameters of the function of star formation for binary systems.

  13. Exo-C: A Space Mission for Direct Imaging and Spectroscopy of Extrasolar Planetary Systems

    Science.gov (United States)

    Stapelfeldt, Karl; Belikov, Ruslan; Marley, Mark; Bryden, Geoff; Serabyn, Eugene; Trauger, John; Cahoy, Kerri; Chakrabarti, Supriya; McElwain, Michael; Meadows, Victoria; Dekens, Frank; Warfield, Keith; Brenner, Michael; Brugarolas, Paul; Effinger, Robert T.; Heeg, Casey; Birsch, Brian; Kissel, Andrew; Kirst, John E.; Lang, Jared; Nissen, Joel; Oseas, Jeffrey M.; Pong, Chris; Sunada, Eric

    2015-01-01

    Exo-C is NASAs first community study of a modest aperture space telescope designed for high contrast observations of exoplanetary systems. The mission will be capable of taking optical spectra of nearby exoplanets in reflected light, discovering previously undetected planets, and imaging structure in a large sample of circumstellar disks. It will obtain unique science results on planets down to super-Earth sizes and serve as a technology pathfinder toward an eventual flagship-class mission to find and characterize habitable Earth-like exoplanets. We present the mission/payload design and highlight steps to reduce mission cost/risk relative to previous mission concepts. Key elements are an unobscured telescope aperture, an internal coronagraph with deformable mirrors for precise wavefront control, and an orbit and observatory design chosen for high thermal stability. Exo-C has a similar telescope aperture, orbit, lifetime, and spacecraft bus requirements to the highly successful Kepler mission (which is our cost reference). The needed technology development is on-course for a possible mission start in 2017. This paper summarizes the study final report completed in January 2015. During 2015 NASA will make a decision on its potential development.

  14. The Synergy of Direct Imaging and Astrometry for Orbit Determination of exo-Earths

    CERN Document Server

    Shao, Michael; Pan, Xiaopei

    2010-01-01

    The holy grail of exoplanet searches is an exo-Earth, an Earth mass planet in the habitable zone around a nearby star. Mass is the most important parameter of a planet and can only be measured by observing the motion of the star around the planet-star center of mass. A single image of a planet, however, does not provide evidence that the planet is Earth mass or that it is in a habitable zone orbit. The planet's orbit, however, can be measured either by imaging the planet at multiple epochs or by measuring the position of the star at multiple epochs by space-based astrometry. The measurement of an exo-planet's orbit by direct imaging is complicated by a number of factors: (1) the inner working angle (IWA); (2) the apparent brightness of the planet depending on the orbital phase; (3) confusion arising from the presence of multiple planets; and (4) the planet-star contrast. In this paper we address the question: "Can a prior astrometric mission that can identify which stars have Earthlike planets significantly i...

  15. Barium Tagging in Solid Xenon for the nEXO Experiment

    Science.gov (United States)

    Chambers, Christopher; Craycraft, Adam; Walton, Timothy; Fairbank, William; nEXO Collaboration

    2016-09-01

    The proposed nEXO experiment utilizes a tonne-scale liquid xenon time projection chamber to search for neutrinoless double beta decay in xenon-136. Positive observation of this decay would determine the nature of the neutrino to be a MAJORANA particle, as well as measure the absolute neutrino mass scale. A critical concern for any rare decay search is reducing or eliminating backgrounds that cannot be distinguished from signal. A powerful background discrimination technique is positive identification of the daughter atom of the decay, in this case barium. This technique, called ``barium tagging'' may be available for a second phase of nEXO operation, allowing for neutrino mass sensitivity beyond the inverted mass hierarchy. Development is underway on a scheme to capture the barium daughter in solid xenon with a cryogenic probe and detect the barium by laser-induced fluorescence inside the solid xenon sample. This presentation reports results on imaging of single barium atoms frozen in a solid xenon matrix, as well as the progress on the freezing and removal of a solid xenon sample from liquid xenon. Graduated.

  16. VUV-sensitive silicon-photomultipliers for the nEXO-experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, Gerrit; Bayerlein, Reimund; Hufschmidt, Patrick; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Ziegler, Tobias; Hoessl, Juergen; Anton, Gisela; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany)

    2016-07-01

    The nEXO (next Enriched Xenon Observatory) experiment will search for the neutrinoless double beta decay of Xe-136 with a liquid xenon TPC (Time ProjectionChamber). The sensitivity of the experiment is related to the energy resolution, which itself depends on the accuracies of the measurements of the amount of drifting electrons and the number of scintillation photons with their wavelength being in the vacuum ultraviolet band. Silicon Photomultipliers (SiPM) shall be used for the detection of the scintillation light, since they can be produced extremely radiopure. Commercially available SiPM do not fulfill all requirements of the nEXO experiment, thus a dedicated development is necessary. To characterize the silicon photomultipliers, we have built a test apparatus for xenon liquefaction, in which a VUV-sensitive photomultiplier tube can be operated together with the SiPM. In this contribution we present our apparatus for the SiPM characterization measurements and our latest results on the test of the silicon photomultipliers for the detection of xenon scintillation light.

  17. Modeling the Exo-Brake and the Development of Strategies for De-Orbit Drag Modulation

    Science.gov (United States)

    Murbach, M. S.; Papadopoulos, P.; Glass, C.; Dwyer-Cianciolo, A.; Powell, R. W.; Dutta, S.; Guarneros-Luna, A.; Tanner, F. A.; Dono, A.

    2016-01-01

    The Exo-Brake is a simple, non-propulsive means of de-orbiting small payloads from orbital platforms such as the International Space Station (ISS). Two de-orbiting experiments with fixed surface area Exo-Brakes have been successfully conducted in the last two years on the TechEdSat-3 and -4 nano-satellite missions. The development of the free molecular flow aerodynamic data-base is presented in terms of angle of attack, projected front surface area variation, and altitude. Altitudes are considered ranging from the 400km ISS jettison altitude to 90km. Trajectory tools are then used to predict de-orbit/entry corridors with the inclusion of the key atmospheric and geomagnetic uncertainties. Control system strategies are discussed which will be applied to the next two planned TechEdSat-5 and -6 nano-satellite missions - thus increasing the targeting accuracy at the Von Karman altitude through the proposed drag modulation technique.

  18. Determining Habitability: Which exoEarths should we search for life?

    CERN Document Server

    Horner, J

    2010-01-01

    Within the next few years, the first Earth-mass planets will be discovered around other stars. Some of those worlds will certainly lie within the classical "habitable zone" of their parent stars, and we will quickly move from knowing of no exoEarths to knowing many. For the first time, we will be in a position to carry out a detailed search for the first evidence of life beyond our Solar System. However, such observations will be hugely taxing and time consuming to perform, and it is almost certain that far more potentially habitable worlds will be known than it is possible to study. It is therefore important to catalogue and consider the various effects which make a promising planet more or less suitable for the development of life. In this work, we review the various planetary, dynamical and stellar influences that could influence the habitability of exoEarths. The various influences must be taken in concert when we attempt to decide where to focus our first detailed search for life. While there is no guara...

  19. ExoCat-1: The Nearby Stellar Systems Catalog for Exoplanet Imaging Missions

    CERN Document Server

    Turnbull, Margaret C

    2015-01-01

    We present the first version of a Nearby Stellar Systems Catalog for Exoplanet Imaging Missions (dubbed by the direct imaging community as "ExoCat") for use in exoplanet direct imaging mission planning. This version, ExoCat-1, includes 2347 stars taken from the Hipparcos Catalogue with measured parallaxes > 33.33 mas (corresponding to a distance of 30 pc). This sample is nearly complete down to V=8, corresponding to stars brighter than ~0.5 solar luminosities (late G-/early K-type dwarf stars at the 30 pc distance limit). For each star we provide astrometry (including Equatorial and Galactic coordinates, parallax, and proper motions), Johnson B and V magnitudes (converted from Hipparcos or Tycho data or taken from the literature), and Ks-band magnitudes from 2MASS (for fainter stars) or K-band magnitudes taken from the literature and converted to 2MASS Ks magnitudes (for bright stars). Using these data we estimate stellar luminosity, effective temperature, stellar radius (in solar and angular units), Earth-eq...

  20. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, Jeffrey A., E-mail: Jeffrey.Mertens@ars.usda.gov [Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604 (United States); Hector, Ronald E.; Bowman, Michael J. [Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604 (United States)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer Thermodynamics of (GalpA){sub n} oligomers binding to an exo-polygalacturonase. Black-Right-Pointing-Pointer Energetics of binding (GalpA){sub n} were determined by ITC. Black-Right-Pointing-Pointer Thermodynamic parameters attributable to individual subsites were determined. - Abstract: Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic process that is enthalpically driven and results in extremely tight binding of the substrate to RPG16. Binding energies in combination with prior biochemical data suggests that RPG16 has the potential for five subsites, -1 to +4, with the greatest contribution to binding energies arising from subsite -1/+1. While the enthalpic contribution to binding decreases substantially for subsites +2 to +4, beneficial entropic effects occur in subsites +3 and +4 leading to increased total free energy as the length of oligomer increases. This information will be useful for additional studies in determining the binding contributions of specific amino acids with mutant enzymes.

  1. Crystal structure of an Exo-1,5-{alpha}-L-arabinofuranosidase from Streptomyces avermitilis provides insights into the mechanism of substrate discrimination between exo- and endo-type enzymes in glycoside hydrolase family 43.

    Science.gov (United States)

    Fujimoto, Zui; Ichinose, Hitomi; Maehara, Tomoko; Honda, Mariko; Kitaoka, Motomitsu; Kaneko, Satoshi

    2010-10-29

    Exo-1,5-α-L-arabinofuranosidases belonging to glycoside hydrolase family 43 have strict substrate specificity. These enzymes hydrolyze only the α-1,5-linkages of linear arabinan and arabino-oligosaccharides in an exo-acting manner. The enzyme from Streptomyces avermitilis contains a core catalytic domain belonging to glycoside hydrolase family 43 and a C-terminal arabinan binding module belonging to carbohydrate binding module family 42. We determined the crystal structure of intact exo-1,5-α-L-arabinofuranosidase. The catalytic module is composed of a 5-bladed β-propeller topologically identical to the other family 43 enzymes. The arabinan binding module had three similar subdomains assembled against one another around a pseudo-3-fold axis, forming a β-trefoil-fold. A sugar complex structure with α-1,5-L-arabinofuranotriose revealed three subsites in the catalytic domain, and a sugar complex structure with α-L-arabinofuranosyl azide revealed three arabinose-binding sites in the carbohydrate binding module. A mutagenesis study revealed that substrate specificity was regulated by residues Asn-159, Tyr-192, and Leu-289 located at the aglycon side of the substrate-binding pocket. The exo-acting manner of the enzyme was attributed to the strict pocket structure of subsite -1, formed by the flexible loop region Tyr-281-Arg-294 and the side chain of Tyr-40, which occupied the positions corresponding to the catalytic glycon cleft of GH43 endo-acting enzymes.

  2. Rotational mixing in close binaries

    CERN Document Server

    de Mink, S E; Langer, N; Yoon, S -Ch; Brott, I; Glebbeek, E; Verkoulen, M; Pols, O R

    2008-01-01

    Rotational mixing is a very important but uncertain process in the evolution of massive stars. We propose to use close binaries to test its efficiency. Based on rotating single stellar models we predict nitrogen surface enhancements for tidally locked binaries. Furthermore we demonstrate the possibility of a new evolutionary scenario for very massive (M > 40 solar mass) close (P < 3 days) binaries: Case M, in which mixing is so efficient that the stars evolve quasi-chemically homogeneously, stay compact and avoid any Roche-lobe overflow, leading to very close (double) WR binaries.

  3. Evolution of Close Binary Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  4. Chaos in Binary Category Computation

    CERN Document Server

    Gonçalves, Carlos Pedro

    2010-01-01

    Category computation theory deals with a web-based systemic processing that underlies the morphic webs, which constitute the basis of categorial logical calculus. It is proven that, for these structures, algorithmically incompressible binary patterns can be morphically compressed, with respect to the local connectivities, in a binary morphic program. From the local connectivites, there emerges a global morphic connection that can be characterized by a low length binary string, leading to the identification of chaotic categorial dynamics, underlying the algorithmically random pattern. The work focuses on infinite binary chains of C2, which is a category that implements an X-OR-based categorial logical calculus.

  5. Low autocorrelation binary sequences

    Science.gov (United States)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  6. Microlensing modulation by binaries

    CERN Document Server

    Dubath, F; Durrer, R; Dubath, Florian; Gasparini, Maria Alice; Durrer, Ruth

    2006-01-01

    We compute the effect of the lens quadrupole on microlensing. The time dependence of the quadrupole can lead to specific modulations of the amplification signal. We study especially binary system lenses in our galaxy. The modulation is observable if the rotation period of the system is smaller than the time over which the amplification is significant and if the impact parameter of the passing light ray is sufficiently close to the Einstein radius so that the amplification is very large. Observations of this modulation can reveal important information on the quadrupole and thus on the gravitational radiation emitted by the lens.

  7. Crystallization and preliminary crystallographic analysis of exo-α-1,5-l-arabinofuranosidase from Streptomyces avermitilis NBRC14893

    OpenAIRE

    2008-01-01

    Exo-α-1,5-l-arabinofuranosidase from S. avermitilis NBRC14893 was crystallized by the sitting-drop vapour-diffusion method. The crystals diffracted to a resolution of 2.2 Å and belonged to space group P212121.

  8. Kinetic properties of two Rhizopus exo-polygalacturonase enzymes hydrolyzing galacturonic acid oligomers using isothermal titration calorimetry

    Science.gov (United States)

    The kinetic characteristics of two Rhizopus oryzae exo-polygalacturonases acting on galacturonic acid oligomers (GalpA) were determined using isothermal titration calorimetry (ITC). RPG15 hydrolyzing (GalpA)2 demonstrated a Km of 55 uM and kcat of 10.3 s^-1^ while RPG16 was shown to have greater af...

  9. The Prediction Of Rough Wall Fluxes To The ExoMars Vehicle

    Science.gov (United States)

    Merrifield, J. A.; Beck, J. C.; Gulhan, A.; Neeb, D.

    2011-05-01

    Ablative heat shields roughen during planetary entry due to the ablation process. This results in enhanced surface fluxes when compared with those obtained from a smooth vehicle. For example, it has been experimentally determined that the turbulent convective flux to a roughened blunt body in hypersonic flow can be up to three times greater than for the hydraulically smooth equivalent case. As such, the potential level of augmentation is significant and has required careful consideration in the prediction of the heat fluxes for the design of the ExoMars thermal protection system (TPS). The fidelity and maturity of current predictive methodologies are insufficient when one considers the potential impact this phenomenon has on TPS design. Commonly, aerothermal databases are derived using methods to determine smooth wall fluxes which are post-processed by correlation to account for rough surface augmentation. The visibility of experimental data used for the construction of these correlations is typically low due to the fact that they originate from strategic weapons programmes. As such, it is difficult to assess the applicability of these correlations to any specific application. The work performed on the ExoMars project to date concerns the modification of the predictive methodology to account for surface roughness, and validation of the methodology against legacy data and a specific set of tests performed in the DLR H2K wind tunnel. Significant progress has been made in this area to support the design of the ExoMars TPS. The roughness model of Krogstad [1] has been implemented into the FGE Navier-Stokes code TINA, with development work including a blending with Van-Driest's roughness model at low k+ (dimensionless roughness height) as well as a modification to account for compressibility. Experiments have been performed at Mach 7 and Mach 5.3 on a PEEK model, and the heat fluxes inferred from infra-red camera measurements of surface temperature. The data clearly

  10. Evolution of Binaries in Dense Stellar Systems

    CERN Document Server

    Ivanova, Natalia

    2011-01-01

    In contrast to the field, the binaries in dense stellar systems are frequently not primordial, and could be either dynamically formed or significantly altered from their primordial states. Destruction and formation of binaries occur in parallel all the time. The destruction, which constantly removes soft binaries from a binary pool, works as an energy sink and could be a reason for cluster entering the binary-burning phase. The true binary fraction is greater than observed, as a result, the observable binary fraction evolves differently from the predictions. Combined measurements of binary fractions in globular clusters suggest that most of the clusters are still core-contracting. The formation, on other hand, affects most the more evolutionary advanced stars, which significantly enhances the population of X-ray sources in globular clusters. The formation of binaries with a compact objects proceeds mainly through physical collisions, binary-binary and single-binary encounters; however, it is the dynamical for...

  11. Spin Correlation in Binary Systems

    CERN Document Server

    Farbiash, N; Farbiash, Netzach; Steinitz, Raphael

    2004-01-01

    We examine the correlation of projected rotational velocities in binary systems. It is an extension of previous work (Steinitz and Pyper, 1970; Levato, 1974). An enlarged data basis and new tests enable us to conclude that there is indeed correlation between the projected rotational velocities of components of binaries. In fact we suggest that spins are already correlated.

  12. Evolutionary Memory in Binary Systems?

    CERN Document Server

    Steinitz, N F R

    2004-01-01

    Correlation between the spins (rotational velocities) in binaries has previously been established. We now continue and show that the degree of spin correlation is independent of the components' separation. Such a result might be related for example to Zhang's non-linear model for the formation of binary stars from a nebula.

  13. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Matthew J. Benacquista

    2013-03-01

    Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  14. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    XuChengqian; ZhaoXiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP)is proposed .A new class of block design-Difference Family Pair (DFP)is also proposed .The relationship between PCSP and DFP,the properties and exising conditions of PCSP and the recursive constructions for PCSP are given.

  15. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    Xu Chengqian; Zhao Xiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP) is proposed. A new class of block design-Difference Family Pair (DFP) is also proposed.The relationship between PCSP and DFP, the properties and existing conditions of PCSP and the recursive constructions for PCSP are given.

  16. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew J.

    2006-02-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  17. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew

    2002-01-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing $10^4 - 10^6$ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct $N$-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  18. Signature Visualization of Software Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Panas, T

    2008-07-01

    In this paper we present work on the visualization of software binaries. In particular, we utilize ROSE, an open source compiler infrastructure, to pre-process software binaries, and we apply a landscape metaphor to visualize the signature of each binary (malware). We define the signature of a binary as a metric-based layout of the functions contained in the binary. In our initial experiment, we visualize the signatures of a series of computer worms that all originate from the same line. These visualizations are useful for a number of reasons. First, the images reveal how the archetype has evolved over a series of versions of one worm. Second, one can see the distinct changes between version. This allows the viewer to form conclusions about the development cycle of a particular worm.

  19. Observing binary inspiral with LIGO

    CERN Document Server

    Finn, L S

    1994-01-01

    Gravitational radiation from a binary neutron star or black hole system leads to orbital decay and the eventual coalescence of the binary's components. During the last several minutes before the binary components coalesce, the radiation will enter the bandwidth of the United States Laser Inteferometer Gravitational-wave Observatory (LIGO) and the French/Italian VIRGO gravitational radiation detector. The combination of detector sensitivity, signal strength, and source density and distribution all point to binary inspiral as the most likely candidate for observation among all the anticipated sources of gravitational radiation for LIGO/VIRGO. Here I review briefly some of the questions that are posed to theorists by the impending observation of binary inspiral.

  20. ExoMol molecular line lists - XIV: The rotation-vibration spectrum of hot SO$_2$

    CERN Document Server

    Underwood, Daniel S; Yurchenko, Sergei N; Huang, Xinchuan; Schwenke, David W; Lee, Timothy J; Clausen, Sønnik; Fateev, Alexander

    2016-01-01

    Sulphur dioxide is well-known in the atmospheres of planets and satellites, where its presence is often associated with volcanism, and in circumstellar envelopes of young and evolved stars as well as the interstellar medium. This work presents a line list of 1.3 billion $^{32}$S$^{16}$O$_2$ vibration-rotation transitions computed using an empirically-adjusted potential energy surface and an ab initio dipole moment surface. The list gives complete coverage up to 8000 cm$^{-1}$ (wavelengths longer than 1.25 $\\mu$m) for temperatures below 2000 K. Infrared absorption cross sections are recorded at 300 and 500 C are used to validated the resulting ExoAmes line list. The line list is made available in electronic form as supplementary data to this article and at www.exomol.com.

  1. First Search for Lorentz and CPT Violation in Double Beta Decay with EXO-200

    CERN Document Server

    Kaufman, L J

    2016-01-01

    This proceedings contribution reports the first experimental search for Lorentz- and CPT-violating signals specifically studying the effect of the Standard-Model Extension (SME) oscillation-free momentum-independent neutrino coupling operator in the double beta decay process. The search has been performed using an exposure of 100 kg yr of $^{136}$Xe with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz violation was found. A two-sided limit of $-2.65 \\times 10^{-5}$ GeV $<$ $\\mathring{a}_{\\mathrm{of}}^{(3)}$ $< 7.60 \\times 10^{-6}$ GeV (90% C.L.) is placed on the relevant coefficient within the SME.

  2. First Search for Lorentz and CPT Violation in Double Beta Decay with EXO-200

    CERN Document Server

    :,; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Díaz, J S; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feyzbkhsh, S; Feldmeier, W; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Homiller, S; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; Njoya, O; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retiére, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Vogel, P; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2016-01-01

    A search for Lorentz- and CPT-violating signals in the double beta decay spectrum of $^{136}$Xe has been performed using an exposure of 100 kg$\\cdot$yr with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz-violation was found, and a two-sided limit of $-2.65 \\times 10^{-5 } \\; \\textrm{GeV} < \\mathring{a}^{(3)}_{\\text{of}} < 7.60 \\times 10^{-6} \\; \\textrm{GeV}$ is placed on the relevant coefficient within the Standard-Model Extension (SME). This is the first experimental study of the effect of the SME-defined oscillation-free and momentum-independent neutrino coupling operator on the double beta decay process.

  3. Spectroscopy of Ba and Ba$^+$ deposits in solid xenon for barium tagging in nEXO

    CERN Document Server

    Mong, B; Walton, T; Chambers, C; Craycraft, A; Benitez-Medina, C; Hall, K; Fairbank, W; Albert, J B; Auty, D J; Barbeau, P S; Basque, V; Beck, D; Breidenbach, M; Brunner, T; Cao, G F; Cleveland, B; Coon, M; Daniels, T; Daugherty, S J; DeVoe, R; Didberidze, T; Dilling, J; Dolinski, M J; Dunford, M; Fabris, L; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Heffner, M; Hughes, M; Jiang, X S; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krucken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Moore, D; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Retiere, F; Rowson, P C; Rozo, M P; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Twelker, K; Vuilleumier, J -L; Walton, J; Weber, M; Wen, L J; Wichoski, U; Yang, L; Yen, Y -R; Zhao, Y B

    2014-01-01

    Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra for deposits of barium atoms and ions in solid xenon matrices are presented. Excitation spectra for prominent emission lines, temperature dependence and bleaching of the fluorescence reveal the existence of different matrix sites. A regular series of sharp lines observed in Ba$^+$ deposits is identified with some type of barium hydride molecule. Lower limits for the fluorescence quantum efficiency of the principal Ba emission transition are reported. Under current conditions, an image of $\\le10^4$ Ba atoms can be obtained. Prospects for imaging single Ba atoms in solid xenon are discussed.

  4. ExoMol molecular line lists - XIV. The rotation-vibration spectrum of hot SO2

    Science.gov (United States)

    Underwood, Daniel S.; Tennyson, Jonathan; Yurchenko, Sergei N.; Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.; Clausen, Sønnik; Fateev, Alexander

    2016-07-01

    Sulphur dioxide is well-known in the atmospheres of planets and satellites, where its presence is often associated with volcanism, and in circumstellar envelopes of young and evolved stars as well as the interstellar medium. This work presents a line list of 1.3 billion 32S16O2 vibration-rotation transitions computed using an empirically adjusted potential energy surface and an ab initio dipole moment surface. The list gives complete coverage up to 8000 cm-1 (wavelengths longer than 1.25 μm) for temperatures below 2000 K. Infrared absorption cross-sections are recorded at 300 and 500 C are used to validated the resulting ExoAmes line list. The line list is made available in electronic form as supplementary data to this article and at www.exomol.com.

  5. ExoMars 2016 EDM SM Mechanical Test Campaign Engineering Results Evaluation

    Science.gov (United States)

    Luison, Dario; Tenore, Amedeo Giancarlo

    2014-06-01

    This paper describes the analytical engineering activities done in the frame of ExoMars Descent Module (EDM) Structural Model (SM) Mechanical Test Campaign performed in ESTEC (for Sinusoidal Test) and in Thales Alenia Space Turin (Italy) laboratories (for Static Test) in the period from February and July 2013.The main results of Sine and Static Tests are described, as well as the updating of the Mathematical Model based on the results of the Base Excitation Vibration Modal Parameters Extraction. The engineering test evaluation activity was concentrated in particular on the simulation of the failure occurred during the sine test. This failure represented a serious issues never encountered in previous tests. Despite the gravity of the phenomenon, in a short time, the engineering was able to prove the structural integrity and to conclude successfully the test.

  6. Rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid

    DEFF Research Database (Denmark)

    Bunch, Lennart; Liljefors, Tommy; Greenwood, Jeremy R

    2003-01-01

    The design and synthesis of conformationally restricted analogues of alpha-amino acids is an often used strategy in medicinal chemistry research. Here we present the rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid (1), a novel conformat...... studies on native 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) (IC(50) > 300 microM, [(3)H]AMPA) or kainic acid (IC(50) > 160 microM, [(3)H]kainic acid) receptors nor in binding studies on the cloned iGluR5,6 subtypes (IC(50) > 300 microM, [(3)H]kainic acid)....

  7. Search for Majorana neutrinos with the first two years of EXO-200 data

    CERN Document Server

    :,; Auty, D J; Barbeau, P S; Beauchamp, E; Beck, D; Belov, V; Benitez-Medina, C; Bonatt, J; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Chaves, J; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; DeVoe, R; Delaquis, S; Didberidze, T; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Hall, C; Herrin, S; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Licciardi, C; Lin, Y H; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; Odian, A; Ostrovskiy, I; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Rivas, A; Rowson, P C; Rozo, M P; Russell, J J; Schubert, A; Sinclair, D; Slutsky, S; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tosi, D; Twelker, K; Vogel, P; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wright, J D; Yang, L; Yen, Y -R; Zeldovich, O Ya; Zhao, Y B

    2014-01-01

    We report on new results from the EXO-200 double-beta-decay experiment with 99.8 kg$\\cdot$yr of Xe-136 exposure, representing an almost fourfold increase from earlier publications. The detector resolution at the Xe-136 double-beta-decay Q-value has been improved to $\\sigma/E=1.53%$ and the background in the $\\pm2\\sigma$ region of interest has been determined to be $(1.7\\pm0.2)\\cdot 10^{-3}$ keV$^{-1}$ kg$^{-1}$ yr$^{-1}$, consistent with previous results. Both the exposure and the background rate are among the best in the literature, resulting in a 90% CL half-life sensitivity of $1.9\\cdot10^{25}$ yr. We find no statistically significant evidence for $0\

  8. Science objectives and Expected performances of NOMAD, an ExoMars TGO instrument

    Science.gov (United States)

    Robert, S.; Vandaele, A. C.; Thomas, I.; Daerden, F.; Depiesse, C.; Drummond, R.; Neary, L.; Willame, Y.; Lopez-Moreno, J. J.; Rodriguez-Gomez, J.; Patel, M. R.; Bellucci, G.

    2015-10-01

    NOMAD, the "Nadir and Occultation for MArs Discovery" spectrometer suite is part of the payload of the 2016 ExoMars Trace Gas Orbiter Mission. This instrument suite will probe the atmosphere of Mars in the infrared, visible and ultraviolet regions covering 0.2 - 0.65 and 2.2 - 4.3μm. Thanks to its very high spectral resolution and multiple channels and observational modes, NOMAD will be able to detect a wide range of atmospheric trace gases, many of which are important markers of geophysical and/or biogenic activity. We will present the instrument, its science objectives and the performances we expect based on simulations we have done so far.

  9. Phylogenetic Co-Occurrence of ExoR, ExoS, and ChvI, Components of the RSI Bacterial Invasion Switch, Suggests a Key Adaptive Mechanism Regulating the Transition between Free-Living and Host-Invading Phases in Rhizobiales.

    Directory of Open Access Journals (Sweden)

    Mary Ellen Heavner

    Full Text Available Both bacterial symbionts and pathogens rely on their host-sensing mechanisms to activate the biosynthetic pathways necessary for their invasion into host cells. The Gram-negative bacterium Sinorhizobium meliloti relies on its RSI (ExoR-ExoS-ChvI Invasion Switch to turn on the production of succinoglycan, an exopolysaccharide required for its host invasion. Recent whole-genome sequencing efforts have uncovered putative components of RSI-like invasion switches in many other symbiotic and pathogenic bacteria. To explore the possibility of the existence of a common invasion switch, we have conducted a phylogenomic survey of orthologous ExoR, ExoS, and ChvI tripartite sets in more than ninety proteobacterial genomes. Our analyses suggest that functional orthologs of the RSI invasion switch co-exist in Rhizobiales, an order characterized by numerous invasive species, but not in the order's close relatives. Phylogenomic analyses and reconstruction of orthologous sets of the three proteins in Alphaproteobacteria confirm Rhizobiales-specific gene synteny and congruent RSI evolutionary histories. Evolutionary analyses further revealed site-specific substitutions correlated specifically to either animal-bacteria or plant-bacteria associations. Lineage restricted conservation of any one specialized gene is in itself an indication of species adaptation. However, the orthologous phylogenetic co-occurrence of all interacting partners within this single signaling pathway strongly suggests that the development of the RSI switch was a key adaptive mechanism. The RSI invasion switch, originally found in S. meliloti, is a characteristic of the Rhizobiales, and potentially a conserved crucial activation step that may be targeted to control host invasion by pathogenic bacterial species.

  10. Enhanced exo-inulinase activity and stability by fusion of an inulin-binding module.

    Science.gov (United States)

    Zhou, Shun-Hua; Liu, Yuan; Zhao, Yu-Juan; Chi, Zhe; Chi, Zhen-Ming; Liu, Guang-Lei

    2016-09-01

    In this study, an inulin-binding module from Bacillus macerans was successfully fused to an exo-inulinase from Kluyveromyces marxianus, creating a hybrid functional enzyme. The recombinant exo-inulinase (rINU), the hybrid enzyme (rINUIBM), and the recombinant inulin-binding module (rIBM) were, respectively, heterologously expressed and biochemically characterized. It was found that both the inulinase activity and the catalytic efficiency (k cat/K m(app)) of the rINUIBM were considerably higher than those of rINU. Though the rINU and the rINUIBM shared the same optimum pH of 4.5, the optimum temperature of the rINUIBM (60 °C) was 5 °C higher than that of the rINU. Notably, the fused IBM significantly enhanced both the pH stability and the thermostability of the rINUIBM, suggesting that the rINUIBM obtained would have more extensive potential applications. Furthermore, the fusion of the IBM could substantially improve the inulin-binding capability of the rINUIBM, which was consistent with the determination of the K m(app). This meant that the fused IBM could play a critical role in the recognition of polysaccharides and enhanced the hydrolase activity of the associated inulinase by increasing enzyme-substrate proximity. Besides, the extra supplement of the independent non-catalytic rIBM could also improve the inulinase activity of the rINU. However, this improvement was much better in case of the fusion. Consequently, the IBM could be designated as a multifunctional domain that was responsible for the activity enhancement, the stabilization, and the substrate binding of the rINUIBM. All these features obtained in this study make the rINUIBM become an attractive candidate for an efficient inulin hydrolysis.

  11. ExoMol: Molecular Line List for Exoplanets and Other Atmospheres

    Science.gov (United States)

    Tennyson, Jonathan; Yurchenko, Sergei N.; Polyansky, Oleg

    2016-06-01

    The discovery of extrasolar planets is one of the major scientific advances of the last two decades. Thousands of planets have now been detected and astronomers are beginning to characterize their composition and physical characteristics. To do this requires a huge quantity of spectroscopic data most of which are not available from laboratory studies. The ExoMol project [1] is generating a comprehensive solution to this problem by providing spectroscopic data on all the molecular transitions of importance in the atmospheres of exoplanets. These data are widely applicable to other problems such studies on cool stars, brown dwarfs and circumstellar environments as well as industrial and technological problems on earth. ExoMol employs a mixture of first principles and empirically tuned quantum mechanical methods to compute comprehensive and very large rotation-vibration and rovibronic line lists. Results span a variety of closed (NaH, SiO, PN, NaCl, KCl, CS) and open (BeH, MgH, CaH, AlO, VO) shell diatomics to triatomics (HCN/HNC, SO_2, H_2S, H_3^+), tetratomics (H_2CO, PH_3, SO_3, H_2O_2), plus methane [2] and nitric acid [3]. This has led directly to the detection of new species in the atmospheres of exoplanets [4]. A new comprehensive data release has just been completed [5]. Progress on and future prospects of the project will be summarised. J. Tennyson, S. N. Yurchenko, Mon. Not. R. astr. Soc., 425, 21, 2012. S. N. Yurchenko, J. Tennyson, J. Bailey, M. D. J. Hollis, G Tinetti, Proc. Nat. Acad. Sci., 111, 9379, 2014. A. I. Pavlyuchko, S. N. Yurchenko, J. Tennyson, Mon. Not. R. astr. Soc., 452, 1702, 2015. A. Tsiaras et al, Astrophys. J., in press. J. Tennyson et al, J. Mol. Spectrosc., in press.

  12. Production of an extensive sunflower protein hydrolysate by sequential hydrolysis with endo- and exo-proteases.

    Directory of Open Access Journals (Sweden)

    Villanueva, Alvaro

    1999-12-01

    Full Text Available A high quality protein isolate has been obtained from defatted sunflower meal by alkaline extraction and isoelectric precipitation. Protein content was increased from 31.2 % in the defatted flour to 97 % in the protein isolate. The percentages of fiber, soluble sugars, polyphenols and residual lipids in the protein isolate were reduced to more than 90 % with respect to the defatted meal. The protein isolate was used as starting material for the generation of an extensive enzymatic protein hydrolysate. The hydrolysis was carried out in a pH stat using sequentially an endo-protease (Alcalase and an exo-protease (Flavourzyme. The protein hydrolysate, with a degree of hydrolysis of 50.7 %, was white and non bitter.

    Se ha obtenido un aislado proteico de alta calidad a partir de harina desengrasada de girasol, mediante extracción alcalina y precipitación isoeléctrica. Se incrementó el contenido proteico desde un 31.2 % en la harina desengrasada hasta un 97 % en el aislado proteico. Los porcentajes de fibra, azúcares solubles, polifenoles y lípidos residuales se redujeron en más del 90 % en el aislado proteico respecto a la harina desengrasada. Se usó el aislado proteico como material de partida para la producción de un hidrolizado enzimático proteico extenso. La hidrólisis se realizó en un reactor usando secuencialmente una endo-proteasa (Alcalasa y una exo-proteasa (Flavorzima. El hidrolizado proteico, con un grado de hidrólisis del 50.7 %, era blanco y no presentaba amargor.

  13. Towards Physarum Binary Adders

    CERN Document Server

    Jones, Jeff; 10.1016/j.biosystems.2010.04.005

    2010-01-01

    Plasmodium of \\emph{Physarum polycephalum} is a single cell visible by unaided eye. The plasmodium's foraging behaviour is interpreted in terms of computation. Input data is a configuration of nutrients, result of computation is a network of plasmodium's cytoplasmic tubes spanning sources of nutrients. Tsuda et al (2004) experimentally demonstrated that basic logical gates can be implemented in foraging behaviour of the plasmodium. We simplify the original designs of the gates and show --- in computer models --- that the plasmodium is capable for computation of two-input two-output gate $ \\to $ and three-input two-output $ \\to $. We assemble the gates in a binary one-bit adder and demonstrate validity of the design using computer simulation.

  14. Towards Physarum binary adders.

    Science.gov (United States)

    Jones, Jeff; Adamatzky, Andrew

    2010-07-01

    Plasmodium of Physarum polycephalum is a single cell visible by unaided eye. The plasmodium's foraging behaviour is interpreted in terms of computation. Input data is a configuration of nutrients, result of computation is a network of plasmodium's cytoplasmic tubes spanning sources of nutrients. Tsuda et al. (2004) experimentally demonstrated that basic logical gates can be implemented in foraging behaviour of the plasmodium. We simplify the original designs of the gates and show - in computer models - that the plasmodium is capable for computation of two-input two-output gate x, y-->xy, x+y and three-input two-output x,y,z-->x yz,x+y+z. We assemble the gates in a binary one-bit adder and demonstrate validity of the design using computer simulation.

  15. Eccentric Binary Millisecond Pulsars

    CERN Document Server

    Freire, Paulo C C

    2009-01-01

    In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have a much wider range of masses (1.3 to > 2 solar masses) than the normal and mildly recycled pulsars found in double neutron star (DNS) systems (1.25 < Mp < 1.44 solar masses). This is very likely to be due to the prolonged accretion episode that is thought to be required to form a MSP. The likely existence of massive MSPs makes them a powerful probe for understanding the behavior of matter at densities larger than that of the atomic nucleus; in particular, the precise measurement of the mass of PSR J1903+0327 ($1.67 +/- 0.01 solar masses) excludes several "soft" equations of state for dense matter.

  16. Dynamical Evolution of Wide Binaries

    Directory of Open Access Journals (Sweden)

    Esmeralda H. Mallada

    2001-01-01

    Full Text Available We simulate numerically encounters of wide binaries with field stars and Giant Molecular Clouds (GMCs by means of the impulse approximation. We analyze the time evolution of the distributions of eccentricities and semimajor axes of wide binaries with given initial conditions, at intervals of 109 yr, up to 1010 yr (assumed age of the Galaxy. We compute the fraction of surviving binaries for stellar encounters, for GMC encounters and for a combination of both, and hence, the dynamical lifetime for different semimajor axes and different masses of binaries (0.5, 1, 1.2, 1.5, 2.5, and 3 Msolar. We find that the dynamical lifetime of wide binaries considering only GMCs is half than that considering only stars. For encounters with GMCs we analyze the influence of the initial inclination of the orbital plane of the binary with respect to the plane perpendicular to the relative velocity vector of the binary and the GMC. We find that the perturbation is maximum when the angle is minimum.

  17. Chaotic zones around gravitating binaries

    CERN Document Server

    Shevchenko, Ivan I

    2014-01-01

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound bodies (a double star, a double black hole, a binary asteroid, etc.) is estimated analytically, in function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the binary periods. The binary's mass ratio, above which such a chaotic zone is universally present, is also estimated.

  18. Modified evolution of stellar binaries from supermassive black hole binaries

    Science.gov (United States)

    Liu, Bin; Wang, Yi-Han; Yuan, Ye-Fei

    2017-04-01

    The evolution of main-sequence binaries resided in the galactic centre is influenced a lot by the central supermassive black hole (SMBH). Due to this perturbation, the stars in a dense environment are likely to experience mergers or collisions through secular or non-secular interactions. In this work, we study the dynamics of the stellar binaries at galactic centre, perturbed by another distant SMBH. Geometrically, such a four-body system is supposed to be decomposed into the inner triple (SMBH-star-star) and the outer triple (SMBH-stellar binary-SMBH). We survey the parameter space and determine the criteria analytically for the stellar mergers and the tidal disruption events (TDEs). For a relative distant and equal masses SMBH binary, the stars have more opportunities to merge as a result from the Lidov-Kozai (LK) oscillations in the inner triple. With a sample of tight stellar binaries, our numerical experiments reveal that a significant fraction of the binaries, ∼70 per cent, experience merger eventually. Whereas the majority of the stellar TDEs are likely to occur at a close periapses to the SMBH, induced by the outer Kozai effect. The tidal disruptions are found numerically as many as ∼10 per cent for a close SMBH binary that is enhanced significantly than the one without the external SMBH. These effects require the outer perturber to have an inclined orbit (≥40°) relatively to the inner orbital plane and may lead to a burst of the extremely astronomical events associated with the detection of the SMBH binary.

  19. Binary Oscillatory Crossflow Electrophoresis

    Science.gov (United States)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  20. Probing thermonuclear burning on accreting neutron stars

    Science.gov (United States)

    Keek, L.

    2008-12-01

    that the models need to be extended with a new heat source. Another rare phenomenon is the occurrence of bursts with recurrence times of less than 30 minutes. In a long set of observations of the source EXO 0748-676 we find for the first time triple bursts, where three bursts occur within 30 minutes. This time is too short to accrete new fuel for the next burst, which suggests that not all hydrogen and helium is burned during the first burst. Finally, using a hydrodynamic stellar evolution code we create a multi-zone numerical model of the neutron star envelope. For the first time we include mixing due to rotation and a rotationally induced magnetic field. We find that thermonuclear burning proceeds in a stable manner at a lower heat flux of the crust for models including mixing. This may explain the observed transition of stable to unstable burning at a lower mass accretion rate than models previously predicted.

  1. 羽衣甘蓝ARC1与Exo70A1蛋白相互作用结构域的分析与鉴定%Analysis and Characterization of Interaction Domain Between ARC1 and Exo70A1 from Ornamental Kale (Brassica oleracea var.acephala)

    Institute of Scientific and Technical Information of China (English)

    曹明明; 杨佳; 李晓屿; 李玉花; 蓝兴国

    2015-01-01

    为阐明羽衣甘蓝自交不亲和信号传递因子ARC1与下游底物Exo70A1相互作用的结构域,利用酵母双杂交系统进行检测与分析.将羽衣甘蓝BoARC1、BoARC1-N端(1~ 279 aa,含有UND结构域)及BoARC1-C端(280 ~ 663 aa,含有U-box结构域和Arm repeat结构域)的序列分别构建到pGBKT7载体中,获得BD-ARC1、BD-ARC1-N和BD-ARC1-C重组质粒.将羽衣甘蓝BoExo70A1、BoExo70A1-△1(1~85aa)、Exo70A1-△2(1~270aa)及Exo70A1-△3(271~638aa,含有Exo70结构域)的序列分别构建到pGADT7载体中,获得AD-Exo70A1、AD-Exo70A1-△1、AD-Exo70A1-△2和AD-Exo70A1-△3重组质粒.将获得的重组质粒分别共转化到酵母Y187菌株中,在双缺陷(-Leu-Trp)酵母培养基中培养与生长.β-gal显色检测结果表明,共转BD-ARC 1-N/BoExo70A1-△1或BD-ARC 1-N/BoExo70A1-△2的酵母在滤纸上显示蓝色,这说明BoARC1的N端与BoExo70A1的N端介导了两者的相互作用.

  2. Stability of binaries. Part II: Rubble-pile binaries

    Science.gov (United States)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  3. Pseudomonas aeruginosa ExoT Induces Atypical Anoikis Apoptosis in Target Host Cells by Transforming Crk Adaptor Protein into a Cytotoxin.

    Science.gov (United States)

    Wood, Stephen; Goldufsky, Josef; Shafikhani, Sasha H

    2015-05-01

    Previously, we demonstrated that Pseudomonas aeruginosa ExoT induces potent apoptosis in host epithelial cells in a manner that primarily depends on its ADP-ribosyltransferase domain (ADPRT) activity. However, the mechanism underlying ExoT/ADPRT-induced apoptosis remains undetermined. We now report that ExoT/ADPRT disrupts focal adhesion sites, activates p38β and JNK, and interferes with integrin-mediated survival signaling; causing atypical anoikis. We show that ExoT/ADPRT-induced anoikis is mediated by the Crk adaptor protein. We found that Crk-/- knockout cells are significantly more resistant to ExoT-induced apoptosis, while Crk-/- cells complemented with Crk are rendered sensitive to ExoT-induced apoptosis. Moreover, a dominant negative (DN) mutant form of Crk phenocopies ExoT-induced apoptosis both kinetically and mechanistically. Crk is generally believed to be a component of focal adhesion (FA) and its role in cellular survival remains controversial in that it has been found to be either pro-survival or pro-apoptosis. Our data demonstrate that although Crk is recruited to FA sites, its function is likely not required for FA assembly or for survival per se. However, when modified by ExoT or by mutagenesis, it can be transformed into a cytotoxin that induces anoikis by disrupting FA sites and interfering with integrin survival signaling. To our knowledge, this is the first example whereby a bacterial toxin exerts its cytotoxicity by subverting the function of an innocuous host cellular protein and turning it against the host cell.

  4. Circumbinary ring, circumstellar disks, and accretion in the binary system UY Aurigae

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ya-Wen; Ho, Paul T. P. [Academia Sinica, Institute of Astronomy and Astrophysics, Taipei, Taiwan (China); Dutrey, Anne; Guilloteau, Stéphane; Di Folco, Emmanuel [Université de Bordeaux, Observatoire Aquitain des Sciences de l' Univers, CNRS, UMR 5804, Laboratoire d' Astrophysique de Bordeaux, 2 rue de l' Observatoire, BP 89, F-33271 Floirac Cedex (France); Piétu, Vincent; Gueth, Fréderic [IRAM, 300 rue de la piscine, F-38406 Saint Martin d' Hères Cedex (France); Beck, Tracy [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Boehler, Yann [Centro de Radioastronomìa y Astrofìsica, UNAM, Apartado Postal 3-72, 58089 Morelia, Michoacàn (Mexico); Bary, Jeff [Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346 (United States); Simon, Michal, E-mail: ywtang@asiaa.sinica.edu.tw [Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2014-09-20

    Recent exo-planetary surveys reveal that planets can orbit and survive around binary stars. This suggests that some fraction of young binary systems which possess massive circumbinary (CB) disks may be in the midst of planet formation. However, there are very few CB disks detected. We revisit one of the known CB disks, the UY Aurigae system, and probe {sup 13}CO 2-1, C{sup 18}O 2-1, SO 5(6)-4(5) and {sup 12}CO 3-2 line emission and the thermal dust continuum. Our new results confirm the existence of the CB disk. In addition, the circumstellar (CS) disks are clearly resolved in dust continuum at 1.4 mm. The spectral indices between the wavelengths of 0.85 mm and 6 cm are found to be surprisingly low, being 1.6 for both CS disks. The deprojected separation of the binary is 1.''26 based on our 1.4 mm continuum data. This is 0.''07 (10 AU) larger than in earlier studies. Combining the fact of the variation of UY Aur B in R band, we propose that the CS disk of an undetected companion UY Aur Bb obscures UY Aur Ba. A very complex kinematical pattern inside the CB disk is observed due to a mixing of Keplerian rotation of the CB disk, the infall and outflow gas. The streaming gas accreting from the CB ring toward the CS disks and possible outflows are also identified and resolved. The SO emission is found to be at the bases of the streaming shocks. Our results suggest that the UY Aur system is undergoing an active accretion phase from the CB disk to the CS disks. The UY Aur B might also be a binary system, making the UY Aur a triple system.

  5. Evidence that the exoH gene of Sinorhizobium meliloti does not appear to influence symbiotic effectiveness with Medicago truncatula 'Jemalong A17'.

    Science.gov (United States)

    Zribi, Kais; Mhadhbi, Haythem; Badri, Yazid; Aouani, Mohamed Elarbi; van Berkum, Peter

    2010-12-01

    The purpose of this study was to identify strains of Sinorhizobium meliloti that formed either an effective or completely ineffective symbiosis with Medicago truncatula L. 'Jemalong A17' and, subsequently, to determine whether differences existed between their exoH genes. Sinorhizobium meliloti TII7 and A5 formed an effective and ineffective symbiosis with M. truncatula 'Jemalong A17', respectively. Using a multilocus sequence typing method, both strains were shown to have chromosomes identical with S. meliloti Rm1021 and RCR2011. The 2260-bp segments of DNA stretching from the 3' end of exoI through open reading frames of hypothetical proteins SM_b20952 and SM_b20953 through exoH into the 5' end of exoK in strains TII7 and Rm1021 differed by a single nucleotide at base 127 of the hypothetical protein SM_b20953. However, the derived amino acid sequences of the exoH genes of effective TII7, ineffective A5, and strain Rm1021 were shown to be identical with each other. Therefore, it would seem unlikely that the gene product of exoH is directly involved with the low efficiency of a symbiosis of strain Rm1021 with M. truncatula 'Jemalong A17'. Complementation or complete genome sequence analyses involving strains TII7 and A5 might be useful approaches to investigate the molecular bases for the differential symbiotic response with M. truncatula 'Jemalong A17'.

  6. A truncated NLR protein, TIR-NBS2, is required for activated defense responses in the exo70B1 mutant.

    Directory of Open Access Journals (Sweden)

    Ting Zhao

    2015-01-01

    Full Text Available During exocytosis, the evolutionarily conserved exocyst complex tethers Golgi-derived vesicles to the target plasma membrane, a critical function for secretory pathways. Here we show that exo70B1 loss-of-function mutants express activated defense responses upon infection and express enhanced resistance to fungal, oomycete and bacterial pathogens. In a screen for mutants that suppress exo70B1 resistance, we identified nine alleles of TIR-NBS2 (TN2, suggesting that loss-of-function of EXO70B1 leads to activation of this nucleotide binding domain and leucine-rich repeat-containing (NLR-like disease resistance protein. This NLR-like protein is atypical because it lacks the LRR domain common in typical NLR receptors. In addition, we show that TN2 interacts with EXO70B1 in yeast and in planta. Our study thus provides a link between the exocyst complex and the function of a 'TIR-NBS only' immune receptor like protein. Our data are consistent with a speculative model wherein pathogen effectors could evolve to target EXO70B1 to manipulate plant secretion machinery. TN2 could monitor EXO70B1 integrity as part of an immune receptor complex.

  7. Binary nucleation beyond capillarity approximation

    NARCIS (Netherlands)

    Kalikmanov, V.I.

    2010-01-01

    Large discrepancies between binary classical nucleation theory (BCNT) and experiments result from adsorption effects and inability of BCNT, based on the phenomenological capillarity approximation, to treat small clusters. We propose a model aimed at eliminating both of these deficiencies. Adsorption

  8. Discs in misaligned binary systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2016-01-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...

  9. Simulating relativistic binaries with Whisky

    Science.gov (United States)

    Baiotti, L.

    We report about our first tests and results in simulating the last phase of the coalescence and the merger of binary relativistic stars. The simulations were performed using our code Whisky and mesh refinement through the Carpet driver.

  10. An adaptable binary entropy coder

    Science.gov (United States)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  11. Magnetic braking in ultracompact binaries

    CERN Document Server

    Farmer, Alison

    2010-01-01

    Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically coupled winds could in fact lead to substantial additional angular momentum losses. We remark that the scaling relations often invoked for the relative importance of gravitational and magnetic braking do not apply, and instead use simple non-empirical expressions for the braking rates. In order to remove significant angular momentum, the wind must be tied to field lines anchored in one of the binary's component stars; uncertainties remain as to the driving mechanism for such a wind. In the case of white dwarf accretors, we find that magnetic braking can potentially remove angular momentum on comparable or even shorter timescales than gravitational waves over a large range in orbital period. We present such a solution for the 17-minute binary AM CVn itself which a...

  12. Cryptography with DNA binary strands.

    Science.gov (United States)

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  13. AN IMPROVED DESIGN OF REVERSIBLE BINARY TO BINARY CODED DECIMAL CONVERTER FOR BINARY CODED DECIMAL MULTIPLICATION

    Directory of Open Access Journals (Sweden)

    Praveena Murugesan

    2014-01-01

    Full Text Available Reversible logic gates under ideal conditions produce zero power dissipation. This factor highlights the usage of these gates in optical computing, low power CMOS design, quantum optics and quantum computing. The growth of decimal arithmetic in various applications as stressed the need to propose the study on reversible binary to BCD converter which plays a greater role in decimal multiplication for providing faster results. The different parameters such as gate count,garbage output and constant input are more optimized in the proposed fixed bit binary to binary coded decimal converter than the existing design.

  14. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  15. Residue arithmetic in binary systems

    OpenAIRE

    Barsi, Ferruccio

    1988-01-01

    A natural approach to the problem of performing mod m computations in a binary system is presented and a solution is suggested which is based upon a straightforward relation between the residues of a same integer X with respect to different moduli. The proposed solution proves fruitful in various applications, such as converting binary integers to residue notation and mod m addition or multiplication. Even if the most usual implementation approach for mod m processors is based on look-up tabl...

  16. NASA ExoPAG Study Analysis Group 5: Flagship Exoplanet Imaging Mission Science Goals and Requirements Report

    CERN Document Server

    Greene, Tom

    2013-01-01

    The NASA Exoplanet Program Analysis Group (ExoPAG) has undertaken an effort to define mission Level 1 requirements for exoplanet direct detection missions at a range of sizes. This report outlines the science goals and requirements for the next exoplanet flagship imaging and spectroscopy mission as determined by the flagship mission Study Analysis Group (SAG) of the NASA Exoplanet Program Analysis Group (ExoPAG). We expect that these goals and requirements will be used to evaluate specific architectures for a future flagship exoplanet imaging and spectroscopy mission, and we expect this effort to serve as a guide and template for similar goals and requirements for smaller missions, an effort that we expect will begin soon. These goals and requirements were discussed, determined, and documented over a 1 year period with contributions from approximately 60 volunteer exoplanet scientists, technologists, and engineers. Numerous teleconferences, emails, and several in-person meetings were conducted to progress on ...

  17. Coevolution of Binaries and Gaseous Discs

    CERN Document Server

    Fleming, David P

    2016-01-01

    The recent discoveries of circumbinary planets by $\\it Kepler$ raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc, and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc that drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for $10^4$ binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentri...

  18. ATel 7470: Optical identification of the X-ray burster EXO 1745-248 in Terzan 5

    Science.gov (United States)

    Ferraro, F. R.; Pallanca, C.; Lanzoni, B.; Cadelano, M.; Massari, D.; Dalessandro, E.; Mucciarelli, A.

    2015-05-01

    We report on the identification of the optical counterpart to the neutron star transient EXO 1745-248 in the stellar system Terzan 5. The identification has been performed by exploiting a set of HST ACS/WFC images acquired in Director Discretionary Time on 2015 April 20 (MJD 57133), approximately 1 month after the Swift/BAT detection of an X-ray outburst from this source (Altamirano et al. ...

  19. Checkpoint genes and Exo1 regulate nearby inverted repeat fusions that form dicentric chromosomes in Saccharomyces cerevisiae.

    Science.gov (United States)

    Kaochar, Salma; Shanks, Lisa; Weinert, Ted

    2010-12-14

    Genomic rearrangements are common, occur by largely unknown mechanisms, and can lead to human diseases. We previously demonstrated that some genome rearrangements occur in budding yeast through the fusion of two DNA sequences that contain limited sequence homology, lie in inverted orientation, and are within 5 kb of one another. This inverted repeat fusion reaction forms dicentric chromosomes, which are well-known intermediates to additional rearrangements. We have previously provided evidence indicating that an error of stalled or disrupted DNA replication forks can cause inverted repeat fusion. Here we analyze how checkpoint protein regulatory pathways known to stabilize stalled forks affect this form of instability. We find that two checkpoint pathways suppress inverted repeat fusion, and that their activities are distinguishable by their interactions with exonuclease 1 (Exo1). The checkpoint kinase Rad53 (Chk2) and recombination protein complex MRX(MRN) inhibit Exo1 in one pathway, whereas in a second pathway the ATR-like kinases Mec1 and Tel1, adaptor protein Rad9, and effector kinases Chk1 and Dun1 act independently of Exo1 to prevent inverted repeat fusion. We provide a model that indicates how in Rad53 or MRX mutants, an inappropriately active Exo1 may facilitate faulty template switching between nearby inverted repeats to form dicentric chromosomes. We further investigate the role of Rad53, using hypomorphic alleles of Rad53 and null mutations in Rad9 and Mrc1, and provide evidence that only local, as opposed to global, activity of Rad53 is sufficient to prevent inverted repeat fusion.

  20. Fission yeast Sec3 and Exo70 are transported on actin cables and localize the exocyst complex to cell poles.

    Directory of Open Access Journals (Sweden)

    Felipe O Bendezú

    Full Text Available The exocyst complex is essential for many exocytic events, by tethering vesicles at the plasma membrane for fusion. In fission yeast, polarized exocytosis for growth relies on the combined action of the exocyst at cell poles and myosin-driven transport along actin cables. We report here the identification of fission yeast Schizosaccharomyces pombe Sec3 protein, which we identified through sequence homology of its PH-like domain. Like other exocyst subunits, sec3 is required for secretion and cell division. Cells deleted for sec3 are only conditionally lethal and can proliferate when osmotically stabilized. Sec3 is redundant with Exo70 for viability and for the localization of other exocyst subunits, suggesting these components act as exocyst tethers at the plasma membrane. Consistently, Sec3 localizes to zones of growth independently of other exocyst subunits but depends on PIP(2 and functional Cdc42. FRAP analysis shows that Sec3, like all other exocyst subunits, localizes to cell poles largely independently of the actin cytoskeleton. However, we show that Sec3, Exo70 and Sec5 are transported by the myosin V Myo52 along actin cables. These data suggest that the exocyst holocomplex, including Sec3 and Exo70, is present on exocytic vesicles, which can reach cell poles by either myosin-driven transport or random walk.

  1. Stereochemistry of spiro-acetalized [60]fullerenes: how the exo and endo stereoisomers influence organic solar cell performance.

    Science.gov (United States)

    Mikie, Tsubasa; Saeki, Akinori; Yamazaki, Yu; Ikuma, Naohiko; Kokubo, Ken; Seki, Shu

    2015-04-29

    Exploiting bis-addition products of fullerenes is a rational way to improve the efficiency of bulk heterojunction-type organic photovoltaic cells (OPV); however, this design inherently produces regio- and stereoisomers that may impair the ultimate performance and fabrication reproducibility. Here, we report unprecedented exo and endo stereoisomers of the spiro-acetalized [60]fullerene monoadduct with methyl- or phenyl-substituted 1,3-dioxane (SAF6). Although there is no chiral carbon in either the reagent or the fullerene, equatorial (eq) rather than axial (ax) isomers are selectively produced at an exo-eq:endo-eq ratio of approximately 1:1 and can be easily separated using silica gel column chromatography. Nuclear Overhauser effect measurements identified the conformations of the straight exo isomer and bent endo isomer. We discuss the origin of stereoselectivity, the anomeric effect, intermolecular ordering in the film state, and the performance of poly(3-hexylthiophene):substituted SAF6 OPV devices. Despite their identical optical and electrochemical properties, their solubilities and space-charge limited current mobilities are largely influenced by the stereoisomers, which leads to variation in the OPV efficiency. This study emphasizes the importance of fullerene stereochemistry for understanding the relationship between stereochemical structures and device output.

  2. Implementation of a complex of measures to fulfill the planetary protection requirements of the ExoMars-2016 mission

    Science.gov (United States)

    Khamidullina, Natalia; Novikova, Nataliya; Deshevaya, Elena; Orlov, Oleg; Guridov, Alexander; Zakharenko, Dmitry; Zaytseva, Olga

    2016-07-01

    The major purpose of the planetary protection program in the ExoMars-2016 mission is to forestall Mars contamination by terrestrial microorganisms. Since Martian descent module is not intended for biological experiments, ExoMars-2016 mission falls under COSPAR category IVa. Within the joint project co-sponsored by ESA and Roscosmos the European side holds full responsibility for ensuring a prescribed level of SC microbiological purity, while the Russian side is charged with compliance of the launch services provided on Baikonur technical complex with the planetary protection requirements that is, specifically, prevention of SC recontamination. To this end, a complex of measures was executed to control microbial contamination of cosmodrome facilities on the prescribed level which included: - regular decontamination of clean rooms using an effective disinfectant and impulse ultraviolet radiation that created favorable conditions for reliable functioning of the ESA clean tent, - replacement of airline filters in the Thermal Conditioning Unit (TCU) air duct for SC conditioning with pure air. The results of microbiological tests performed in the period of 2015 - 2016 lead to the conclusion that the Baikonur clean rooms (ISO class 8), TCU air ducts and Air Thermal Control System (ATCS) at launch site are ready for the launch campaign and that the Russian side fulfilled the planetary protection requirements of the ExoMars-2016 mission.

  3. Control of Grifola frondosa Morphology by Agitation and Aeration for Improving Mycelia and Exo-Polymer Production.

    Science.gov (United States)

    Cui, Feng-Jie; Chen, Xiao-Xiao; Liu, Wei-Min; Sun, Wen-Jing; Huo, Shuhao; Yang, Yan

    2016-06-01

    The present study describes the improved mycelia and exo-polymer production under control of Grifola frondosa morphology by changing the aeration rate and agitation intensity in a 25-L stirred fermentor. The aeration rate of 1.0 vvm yielded a highest mycelia biomass of 24.754 g/L with the lowest pellet percentage of 20.5 %. The maximum exo-polymer (2.324 g/L) was achieved at 0.75 vvm with mycelia polysaccharide production (0.321 g/g), whereas clumps and filaments dominated the ratios of 45.6 and 33.9 %, respectively. The change of aeration rate and agitation intensity had slight influence on the monosaccharide compositions in exo-polymers and significantly affected glucose and mannose contents in the mycelia polysaccharides. These findings will provide a clue for exploring the relationship between fermentation parameters, morphologies, and polysaccharide synthesis pathway of G. frondosa.

  4. Phosphorylation of the exocyst protein Exo84 by TBK1 promotes insulin-stimulated GLUT4 trafficking.

    Science.gov (United States)

    Uhm, Maeran; Bazuine, Merlijn; Zhao, Peng; Chiang, Shian-Huey; Xiong, Tingting; Karunanithi, Sheelarani; Chang, Louise; Saltiel, Alan R

    2017-03-21

    Insulin stimulates glucose uptake through the translocation of the glucose transporter GLUT4 to the plasma membrane. The exocyst complex tethers GLUT4-containing vesicles to the plasma membrane, a process that requires the binding of the G protein (heterotrimeric guanine nucleotide-binding protein) RalA to the exocyst complex. We report that upon activation of RalA, the protein kinase TBK1 phosphorylated the exocyst subunit Exo84. Knockdown of TBK1 blocked insulin-stimulated glucose uptake and GLUT4 translocation; knockout of TBK1 in adipocytes blocked insulin-stimulated glucose uptake; and ectopic overexpression of a kinase-inactive mutant of TBK1 reduced insulin-stimulated glucose uptake in 3T3-L1 adipocytes. The phosphorylation of Exo84 by TBK1 reduced its affinity for RalA and enabled its release from the exocyst. Overexpression of a kinase-inactive mutant of TBK1 blocked the dissociation of the TBK1/RalA/exocyst complex, and treatment of 3T3-L1 adipocytes with specific inhibitors of TBK1 reduced the rate of complex dissociation. Introduction of phosphorylation-mimicking or nonphosphorylatable mutant forms of Exo84 blocked insulin-stimulated GLUT4 translocation. Thus, these data indicate that TBK1 controls GLUT4 vesicle engagement and disengagement from the exocyst, suggesting that exocyst components not only constitute a tethering complex for the GLUT4 vesicle but also act as "gatekeepers" controlling vesicle fusion at the plasma membrane.

  5. NOMAD on the ExoMars TGO 2016 mission: MAIT and characterisation testing

    Science.gov (United States)

    Vandaele, Ann C.; Neefs, Eddy; Lopez-Moreno, J. J.; Rodriguez Gomez, Julio; Drummond, Rachel; Patel, Manish; Thomas, Ian; Gissot, Samuel; Depiesse, Cedric; Ben Moussa, Ali; Giordanengo, Boris; Bellucci, Giancarlo

    NOMAD, the “Nadir and Occultation for MArs Discovery” spectrometer suite has been selected by ESA and NASA to be part of the payload of the ExoMars Trace Gas Orbiter mission 2016. This instrument suite will conduct a spectroscopic survey of Mars’ atmosphere in the UV, visible and IR regions covering the 0.2-0.65 and 2.2-4.3 μm spectral ranges. NOMAD’s observation modes include solar occultation, nadir and limb observations. The NOMAD instrument is composed of 3 channels: a solar occultation only channel (SO) operating in the infrared wavelength domain, a second infrared channel capable of observing nadir, solar occultation and limb observations (LNO), and an ultraviolet/visible channel (UVIS) that can work in all observation modes. The spectral resolution of SO and LNO surpasses previous surveys in the infrared by more than one order of magnitude. NOMAD offers an integrated instrument combination of a flight-proven concept (SO is a copy of SOIR on Venus Express), and innovations based on existing and proven instrumentation (LNO is based on SOIR/VEX and UVIS has heritage from the ExoMars lander), that will provide mapping and vertical profile information at high spatio-temporal resolution. The three channels have each their own ILS and optical bench, but share the same single interface to the S/C. The NOMAD flight model is due for delivery to ESA in January 2015. We will present results so far of the manufacturing, assembly and especially testing of the various components. The UV CCDs have been characterised in thermal-vacuum; optical fibres have been studied with UV exposure to look at transmission degradation; the IR AOTFs have been tested for their transfer functions; lifetime and vibration testing has been carried out on the flip mirror mechanism. These are all vital inputs to the scientific results from NOMAD. Acknowledgements - The research program was supported by the Belgian Federal Science Policy Office and the European Space Agency (ESA PRODEX

  6. Exploiting physical constraints for multi-spectral exo-planet detection

    Science.gov (United States)

    Thiébaut, Éric; Devaney, Nicholas; Langlois, Maud; Hanley, Kenneth

    2016-07-01

    We derive a physical model of the on-axis PSF for a high contrast imaging system such as GPI or SPHERE. This model is based on a multi-spectral Taylor series expansion of the diffraction pattern and predicts that the speckles should be a combination of spatial modes with deterministic chromatic magnification and weighting. We propose to remove most of the residuals by fitting this model on a set of images at multiple wavelengths and times. On simulated data, we demonstrate that our approach achieves very good speckle suppression without additional heuristic parameters. The residual speckles1, 2 set the most serious limitation in the detection of exo-planets in high contrast coronographic images provided by instruments such as SPHERE3 at the VLT, GPI4, 5 at Gemini, or SCExAO6 at Subaru. A number of post-processing methods have been proposed to remove as much as possible of the residual speckles while preserving the signal from the planets. These methods exploit the fact that the speckles and the planetary signal have different temporal and spectral behaviors. Some methods like LOCI7 are based on angular differential imaging8 (ADI), spectral differential imaging9, 10 (SDI), or on a combination of ADI and SDI.11 Instead of working on image differences, we propose to tackle the exo-planet detection as an inverse problem where a model of the residual speckles is fit on the set of multi-spectral images and, possibly, multiple exposures. In order to reduce the number of degrees of freedom, we impose specific constraints on the spatio-spectral distribution of stellar speckles. These constraints are deduced from a multi-spectral Taylor series expansion of the diffraction pattern for an on-axis source which implies that the speckles are a combination of spatial modes with deterministic chromatic magnification and weighting. Using simulated data, the efficiency of speckle removal by fitting the proposed multi-spectral model is compared to the result of using an approximation

  7. Characterization of rocks buried in the subsurface by the GPR WISDOM/ExoMars 2020

    Science.gov (United States)

    Hervé, Yann; Ciarletti, Valérie; Le Gall, Alice; Guiffaut, Christophe

    2016-10-01

    The search for evidence of past life on Mars is the main objective of the ESA-Roscosmos ExoMars Rover mission. Given the hostile environment at the surface, if such evidence is to be found anywhere, it will most likely be in the subsurface. This is why the ExoMars rover mission has been optimized to investigate the subsurface. Among the instruments accommodated onboard the Rover, the polarimetric ground penetrating radar WISDOM (Water Ice Subsurface Deposits Observation On Mars, Ciarletti et al., 2011) has been designed to investigate the shallow subsurface and search for the most favorable locations where to drill and collect samples for analysis. WISDOM is able to probe down to a depth of few meters with a vertical resolution of a few centimeters, and will provide key information on the geological context of the environment.In particular, insights into density, size and shape of the rocks buried beneath the rover would be clues for a better understanding of the geological and hydrological history of the Rover site. In addition, the density and size of the buried rocks will have to be taken into account for the safety of the drilling operations.In this paper, we will focus on the ability of WISDOM to detect, localize and characterize (in terms of size and shape), rocks in the shallow subsurface of Mars. More specifically, we use a 3D numerical code based on the Finite Difference in Time Domain method to model the antenna system of WISDOM and simulate the instrument operations on realistic environments with buried rocks. In this approach, size-frequency distribution of rocks in agreement with observations from orbit and by cameras operated from the Martian surface will be considered. We will present results of simulations for different density and shape of buried rocks, including critical configurations where the density of rocks is too high to allow individual detection of rocks. In addition, we will present experimental data for comparison with the simulated data

  8. Unsupervised learning of binary vectors

    Science.gov (United States)

    Copelli Lopes da Silva, Mauro

    In this thesis, unsupervised learning of binary vectors from data is studied using methods from Statistical Mechanics of disordered systems. In the model, data vectors are distributed according to a single symmetry-breaking direction. The aim of unsupervised learning is to provide a good approximation to this direction. The difference with respect to previous studies is the knowledge that this preferential direction has binary components. It is shown that sampling from the posterior distribution (Gibbs learning) leads, for general smooth distributions, to an exponentially fast approach to perfect learning in the asymptotic limit of large number of examples. If the distribution is non-smooth, then first order phase transitions to perfect learning are expected. In the limit of poor performance, a second order phase transition ("retarded learning") is predicted to occur if the data distribution is not biased. Using concepts from Bayesian inference, the center of mass of the Gibbs ensemble is shown to have maximal average (Bayes-optimal) performance. This upper bound for continuous vectors is extended to a discrete space, resulting in the clipped center of mass of the Gibbs ensemble having maximal average performance among the binary vectors. To calculate the performance of this best binary vector, the geometric properties of the center of mass of binary vectors are studied. The surprising result is found that the center of mass of infinite binary vectors which obey some simple constraints, is again a binary vector. When disorder is taken into account in the calculation, however, a vector with continuous components is obtained. The performance of the best binary vector is calculated and shown to always lie above that of Gibbs learning and below the Bayes-optimal performance. Making use of a variational approach under the replica symmetric ansatz, an optimal potential is constructed in the limits of zero temperature and mutual overlap 1. Minimization of this potential

  9. Production and Optimization of Exo and Endocellulases from Thermophilic Fungi Scytalidium thermophilum SKESMBKU02

    Directory of Open Access Journals (Sweden)

    Sriyamjalla SANTOSHKUMAR

    2016-01-01

    Full Text Available The study aimed at isolation and screening of thermophilic cellulase producer, optimization and stability studies for maximum cellulase production. Fifteen thermophilic cellulase producing fungi were isolated from thermogenic habitats (vegetable market compost, mushroom compost, horse dung, municipal waste, nests of birds, decomposing litter, soils from furnace area, cattle dung, zoo dump, and industrial waste. of Telangana. All the fungal isolates were screened for their ability to produce cellulases. Scytalidium thermophilum SKESMBKU02 showed the highest cellulase activity in screening and was selected for further studies. The results showed that S. thermophilum SKESMBKU02 found to have high cellulolytic activity at 45 °C and pH 5.0 - 6.0. Optimization of enzyme production was studied in different carbon and nitrogen sources. The endo and exoglucanase activities were higher in media containing glucose as their carbon source followed by xylose. Yeast extract and peptone were good nitrogen sources for endoglucanase and exoglucanase activity respectively. The organism showed maximum dry weight in (NH42SO4 and NH4Cl. The exo and endocellulases produced by the S. thermophilum SKESMBKU02 were highly stable at pH 8.0 and temperature of 75 °C. The results indicate that the endo and exocellulases produced by the fungi were more stable at high temperature and alkaline pH.

  10. Kepler and Ground-based Transits of the Exo-Neptune HAT-P-11b

    CERN Document Server

    Deming, Drake; Jackson, Brian; Peterson, Steven W; Agol, Eric; Knutson, Heather A; Jennings, Donald E; Haase, Flynn; Bays, Kevin

    2011-01-01

    We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B-band) and near-IR (J-band). Both the planet and host star are smaller than previously believed; our analysis yields Rp=4.31 +/-0.06 Earth-radii, and Rs = 0.683 +/-0.009 solar radii, both about 3-sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler tr...

  11. Crushable Structure for the Landing Impact of a European Mars Exploration Mission (ExoMars 2016)

    Science.gov (United States)

    del Campo, F.; Bernar, E.; Biondetti, G.; Jauregui, Y. E.; Walloschek, T.

    2012-07-01

    The first mission of the ExoMars programme, scheduled to arrive at Mars in 2016, includes an Entry, Descent and Landing Demonstrator Module (EDM). One of the EDM objectives is to demonstrate the possibility to safely absorb the landing impact by means of a deformable structure placed under the Surface Platform (SP), the EDM sub-module reaching ground. This is one of the key technologies in preparation for ESA's contribution to subsequent missions to Mars. SENER is responsible for several structures and mechanisms for the EDM, with TAS-I as Prime contractor. The paper focuses on the Crushable Structure, which is the main element affected by the impact. Its function is to absorb the landing impact after thruster switch off at around 2 meters over the Martian surface, allowing a safe landing for the equipments in terms of acceleration levels, and for the whole structure in terms of stability and non-overturning. An optimized structure has been designed for this purpose, within a restricted envelope, able to meet these requirements for a wide range of terrain configurations, including rocks and slopes.

  12. THE EXO-PLANETARY SYSTEM OF 55 CANCRI AND THE TITIUS-BODE LAW

    Directory of Open Access Journals (Sweden)

    Arcadio Poveda

    2008-01-01

    Full Text Available El reciente descubrimiento de un quinto planeta ligado a 55 Cancri (Fischer et al. 2007 nos ha motivado a investigar si este sistema exo-planetario se ajusta a alguna forma de la ley de Titius-Bode (TB. Encontramos que una simple relación TB exponencial reproduce muy bien los cinco semiejes mayores observados siempre y cuando se asigne el número 6 al planeta con el semieje más grande. Esta forma de contar deja un vacío en la posición n = 5, una situación curiosamente reminiscente a la ley TB en nuestro propio sistema planetario, antes del descubrimiento de Ceres. La aplicación de una ley TB exponencial a 55 Cancri nos permite predecir la existencia de un planeta con a 2:0 UA y con un periodo de P 1130 días localizado en la gran brecha entre a = 0:781 UA (P = 260 días y a = 5:77 UA (P = 5218 días correspondientes a los dos más grandes periodos observados. Con menos certeza, también predecimos un séptimo planeta en a 15 UA con P 62 años.

  13. [The endo-exo prosthesis for patients with a problematic amputation stump].

    Science.gov (United States)

    Frölke, Jan Paul M; van de Meent, Henk

    2010-01-01

    Following lower limb amputation, quality of life is highly related to the ability to use a prosthetic limb. The conventional way to attach a prosthetic limb to the body is with a socket. Many patients experience serious discomfort wearing a conventional prosthesis because of pain, instability during walking, pressure sores, bad smell or skin irritation. In addition, sitting is uncomfortable and pelvic and lower back pain due to unstable gait is often seen in these patients. The main disadvantage of the current prosthesis is the attachment of a rigid prosthesis socket to a soft and variable body. The socket must fit tightly for stability during walking but should also be comfortable for sitting. The implantation of an osseointegrated, intramedullary, transcutaneously conducted prosthesis is a new procedure for attaching a limb prosthesis to the human body without the disadvantages of the conventional prosthesis. The intramedullary prosthesis is designed with a rough surface resembling cancellous bone to enable a secure solid integration with the long bone. We treated two patients with this new prosthesis, a 44-year-old man after a transfemoral amputation, and a 32-year-old woman after a lower leg amputation; both amputations were necessary because of trauma. Those two patients are now, more than one year after the operation, showing excellent functional results without infectious complications. We assume that endo-exo prosthesis may be a promising option for selected patients unable to use a conventional prosthesis because of a problematic amputation stump.

  14. The ExoMol project: Software for computing large molecular line lists

    CERN Document Server

    Tennyson, Jonathan

    2016-01-01

    The use of variational nuclear motion programs to compute line lists of transition frequencies and intensities is now a standard procedure. The ExoMol project has used this technique to generate line lists for studies of hot bodies such as the atmospheres of exoplanets and cool stars. The resulting line list can be huge: many contain 10 billion or more transitions. This software update considers changes made to our programs during the course of the project to allow for such calculations. This update considers three programs: {\\sc Duo} which computed vibronic spectra for diatomics, {\\sc DVR3D} which computes rotation-vibration spectra for triatomics, and {\\sc TROVE} which computes rotation-vibration spectra for general polyatomic systems. Important updates in functionality include the calculation of quasibound (resonance) states and Land\\'e $g$-factors by {\\sc Duo} and the calculation of resonance states by {\\sc DVR3D}. Significant algorithmic improvements are reported for both {\\sc DVR3D} and {\\sc TROVE}. All...

  15. Mixed-metal chalcogenide tetrahedral clusters with an exo-polyhedral metal fragment.

    Science.gov (United States)

    Yuvaraj, K; Roy, Dipak Kumar; Anju, V P; Mondal, Bijnaneswar; Varghese, Babu; Ghosh, Sundargopal

    2014-12-07

    The reaction of metal carbonyl compounds with group 6 and 8 metallaboranes led us to report the synthesis and structural characterization of several novel mixed-metal chalcogenide tetrahedral clusters. Thermolysis of arachno-[(Cp*RuCO)2B2H6], 1, and [Os3(CO)12] in the presence of 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Os3(CO)9}S], 3, and [Cp*Ru(μ-H){Os3(CO)11}], 4. In a similar fashion, the reaction of [(Cp*Mo)2B5H9], 2, with [Ru3(CO)12] and 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Ru3(CO)9}S], 5, and conjuncto-[(Cp*Mo)2B5H8(μ-H){Ru3(CO)9}S], 6. Both compounds 3 and 5 can be described as 50-cve (cluster valence electron) mixed-metal chalcogenide clusters, in which a sulfur atom replaces one of the vertices of the tetrahedral core. Compounds 3 and 5 possess a [M3S] tetrahedral core, in which the sulfur is attached to an exo-metal fragment, unique in the [M3S] metal chalcogenide tetrahedral arrangements. All the compounds have been characterized by mass spectrometry, IR, and (1)H, (11)B and (13)C NMR spectroscopy in solution, and the solid state structures were unequivocally established by crystallographic analysis of compounds 3, 5 and 6.

  16. ASTEP South: An Antarctic Search for Transiting ExoPlanets around the celestial South pole

    CERN Document Server

    Crouzet, Nicolas; Agabi, Karim; Rivet, Jean-Pierre; Bondoux, Erick; Challita, Zalpha; Fanteï-Caujolle, Yan; Fressin, François; Mékarnia, Djamel; Schmider, François-Xavier; Valbousquet, Franck; Blazit, Alain; Bonhomme, Serge; Abe, Lyu; Daban, Jean-Baptiste; Gouvret, Carole; Fruth, Thomas; Rauer, Heike; Erikson, Anders; Barbieri, Mauro; Aigrain, Suzanne; Pont, Frédéric

    2009-01-01

    ASTEP South is the first phase of the ASTEP project (Antarctic Search for Transiting ExoPlanets). The instrument is a fixed 10 cm refractor with a 4kx4k CCD camera in a thermalized box, pointing continuously a 3.88 degree x 3.88 degree field of view centered on the celestial South pole. ASTEP South became fully functional in June 2008 and obtained 1592 hours of data during the 2008 Antarctic winter. The data are of good quality but the analysis has to account for changes in the point spread function due to rapid ground seeing variations and instrumental effects. The pointing direction is stable within 10 arcseconds on a daily timescale and drifts by only 34 arcseconds in 50 days. A truly continuous photometry of bright stars is possible in June (the noon sky background peaks at a magnitude R=15 arcsec-2 on June 22), but becomes challenging in July (the noon sky background magnitude is R=12.5 arcsec?2 on July 20). The weather conditions are estimated from the number of stars detected in the field. For the 2008...

  17. Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements.

    Science.gov (United States)

    Johnson, B Carol; Litorja, Maritoni; Fowler, Joel B; Shirley, Eric L; Barnes, Robert A; Butler, James J

    2013-11-20

    Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated.

  18. Searching for life on Mars: selection of molecular targets for ESA's aurora ExoMars mission.

    Science.gov (United States)

    Parnell, John; Cullen, David; Sims, Mark R; Bowden, Stephen; Cockell, Charles S; Court, Richard; Ehrenfreund, Pascale; Gaubert, Francois; Grant, William; Parro, Victor; Rohmer, Michel; Sephton, Mark; Stan-Lotter, Helga; Steele, Andrew; Toporski, Jan; Vago, Jorge

    2007-08-01

    The European Space Agency's ExoMars mission will seek evidence of organic compounds of biological and non-biological origin at the martian surface. One of the instruments in the Pasteur payload may be a Life Marker Chip that utilizes an immunoassay approach to detect specific organic molecules or classes of molecules. Therefore, it is necessary to define and prioritize specific molecular targets for antibody development. Target compounds have been selected to represent meteoritic input, fossil organic matter, extant (living, recently dead) organic matter, and contamination. Once organic molecules are detected on Mars, further information is likely to derive from the detailed distribution of compounds rather than from single molecular identification. This will include concentration gradients beneath the surface and gradients from generic to specific compounds. The choice of biomarkers is informed by terrestrial biology but is wide ranging, and nonterrestrial biology may be evident from unexpected molecular distributions. One of the most important requirements is to sample where irradiation and oxidation are minimized, either by drilling or by using naturally excavated exposures. Analyzing regolith samples will allow for the search of both extant and fossil biomarkers, but sequential extraction would be required to optimize the analysis of each of these in turn.

  19. [Heterologous expression, purification and characterization of exo-inulinase from Kluyveromyces marxianus YX01].

    Science.gov (United States)

    Li, Yimin; Gao, Jiaoqi; Yuan, Wenjie; Xiang, Ruijuan; Hou, Shengbo

    2015-05-01

    To improve the inulinase application in biotechnology, the characteristic of inulinase from Kluyveromyces marxianus YX01 was investigated. The inu gene of K. marxianus YX01 was transformed into Pichiapastoris GS115 host cells with molecular biology techniques. Then we achieved the heterologous expression of exo-inulinase whose molecular mass was about 86.0 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Furthermore, six His-tag was added to the inulinase and a two-step method was applied in the purification of inulinase, including concentration via dialysis by polyethylene glycol 20 000 and metal Ni-NTA Agarose affinity adsorption. The purification factor of purified protein was 3.6 and the recovery rate of enzyme activity was 33.1%. We characterized the purified inulinase. The optimum temperature was 60 degrees C and pH was 4.62. When inulin and sucrose were used as substrates, the K(m) and V(max) values were 80.53 g/L vs 4.49 g/(L x min) and 183.10 g/L vs 20.20 g/(L x min), respectively. In addition, metal ions including Mn2+, Ca2+, Cu2+, Zn2+ and Fe2+ exhibited different degrees of inhibition on the enzyme activity, and Cu2+, Zn2+ and Fe2+ exhibited the most significant inhibition. Our findings might lay a good foundation for industrial application of inulinase.

  20. Mapping Protein-DNA Interactions Using ChIP-exo and Illumina-Based Sequencing.

    Science.gov (United States)

    Barfeld, Stefan J; Mills, Ian G

    2016-01-01

    Chromatin immunoprecipitation (ChIP) provides a means of enriching DNA associated with transcription factors, histone modifications, and indeed any other proteins for which suitably characterized antibodies are available. Over the years, sequence detection has progressed from quantitative real-time PCR and Southern blotting to microarrays (ChIP-chip) and now high-throughput sequencing (ChIP-seq). This progression has vastly increased the sequence coverage and data volumes generated. This in turn has enabled informaticians to predict the identity of multi-protein complexes on DNA based on the overrepresentation of sequence motifs in DNA enriched by ChIP with a single antibody against a single protein. In the course of the development of high-throughput sequencing, little has changed in the ChIP methodology until recently. In the last three years, a number of modifications have been made to the ChIP protocol with the goal of enhancing the sensitivity of the method and further reducing the levels of nonspecific background sequences in ChIPped samples. In this chapter, we provide a brief commentary on these methodological changes and describe a detailed ChIP-exo method able to generate narrower peaks and greater peak coverage from ChIPped material.

  1. Flight Mechanics of the Entry, Descent and Landing of the ExoMars Mission

    Science.gov (United States)

    HayaRamos, Rodrigo; Boneti, Davide

    2007-01-01

    ExoMars is ESA's current mission to planet Mars. A high mobility rover and a fixed station will be deployed on the surface of Mars. This paper regards the flight mechanics of the Entry, Descent and Landing (EDL) phases used for the mission analysis and design of the Baseline and back-up scenarios of the mission. The EDL concept is based on a ballistic entry, followed by a descent under parachutes and inflatable devices (airbags) for landing. The mission analysis and design is driven by the flexibility in terms of landing site, arrival dates and the very stringent requirement in terms of landing accuracy. The challenging requirements currently imposed to the mission need innovative analysis and design techniques to support system design trade-offs to cope with the variability in entry conditions. The concept of the Global Entry Corridor has been conceived, designed, implemented and successfully validated as a key tool to provide a global picture of the mission capabilities in terms of landing site reachability.

  2. Setup for SiPM characterization in liquid xenon for the nEXO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hufschmidt, Patrick; Bayerlein, Reimund; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Wredel, Gerrit; Ziegler, Tobias; Anton, Gisela; Hoessl, Juergen; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen Nuernberg (Germany)

    2016-07-01

    The nEXO (next enriched xenon observatory) is a future experiment to search for the neutrinoless double beta decay of Xe-136 with a single-phase time-projection-chamber filled with liquid xenon. Besides position resolved detection of the released charge with low noise electronics, efficient collection and detection of the xenon scintillation light with its short wavelength of 175 nm is important to obtain good energy resolution. Due to the demands on radiopurity of the materials employed in the detector, Silicon Photomultipliers (SiPM) shall be used to detect the scintillation light. Dedicated SiPMs, compatible with the requirements of the experiment, have to be developed. In order to characterize SiPMs - for example with respect to photon detection efficiency at 175 nm, cross-talk probability, dark-rate, after-pulse probability - we have set up a SiPM test stand in which SiPMs can be operated in liquid or in gaseous xenon. Cooling is performed with a cold finger immersed in liquid nitrogen. Scintillation photons are produced by the interaction of alpha particles from a radioactive source. In addition to the SiPMs, a VUV-sensitive photomultiplier tube is present in the xenon cell so that coincidence measurements can be performed. In this contribution we present the status of our test setup.

  3. The NOMAD Spectrometer Suite on ExoMars Trace Gas Orbiter

    Science.gov (United States)

    Carine Vandaele, Ann; Lopez-Moreno, Jose-Juan; Patel, Manish R.; Bellucci, Giancarlo; Neefs, Eddy; Thomas, Ian R.; Drummond, Rachel; Rodriguez-Gomez, Julio; Daerden, Frank

    2016-04-01

    NOMAD (Nadir and Occultation for MArs Discovery) is a suite of three high-resolution spectrometers on-board the ExoMars Trace Gas Orbiter. The instrument will be able to detect and map a wide variety of Martian gases in unprecedented detail. NOMAD's three spectrometers cover the UV-visible (UVIS channel - 200-650nm) and infrared ranges (SO and LNO channels - 2.2-4.3μm), operating in solar occultation, limb and nadir-viewing modes, generating a huge dataset of Martian atmospheric observations during the mission across a wide spectral range. NOMAD has the resolving power to identify many trace gases that exhibit absorption features within the spectral range of the three channels. The order-of-magnitude increase in spectral resolution over previous instruments will enable spatial and temporal mapping of several isotopologues of methane and water, providing important measurements of the Martian D/H and methane isotope ratios globally. Sensitivity studies have shown that, using expected SNR values, NOMAD should have the ability to measure methane concentrations NOMAD will also continue to monitor the major seasonal cycles on Mars, extending existing datasets made by successive space missions in the past decade.

  4. Exoplanets Bouncing Between Binary Stars

    CERN Document Server

    Moeckel, Nickolas

    2012-01-01

    Exoplanetary systems are found not only among single stars, but also binaries of widely varying parameters. Binaries with separations of 100--1000 au are prevalent in the Solar neighborhood; at these separations planet formation around a binary member may largely proceed as if around a single star. During the early dynamical evolution of a planetary system, planet--planet scattering can eject planets from a star's grasp. In a binary, the motion of a planet ejected from one star has effectively entered a restricted three-body system consisting of itself and the two stars, and the equations of motion of the three body problem will apply as long as the ejected planet remains far from the remaining planets. Depending on its energy, escape from the binary as a whole may be impossible or delayed until the three-body approximation breaks down, and further close interactions with its planetary siblings boost its energy when it passes close to its parent star. Until then this planet may be able to transition from the ...

  5. Formation of Kuiper Belt Binaries

    CERN Document Server

    Goldreich, P; Sari, R; Goldreich, Peter; Lithwick, Yoram; Sari, Re'em

    2002-01-01

    It appears that at least several percent of large Kuiper belt objects are members of wide binaries. Physical collisions are too infrequent to account for their formation. Collisionless gravitational interactions are more promising. These provide two channels for binary formation. In each, the initial step is the formation of a transient binary when two large bodies penetrate each other's Hill spheres. Stabilization of a transient binary requires that it lose energy. Either dynamical friction due to small bodies or the scattering of a third large body can be responsible. Our estimates favor the former, albeit by a small margin. We predict that most objects of size comparable to those currently observed in the Kuiper belt are members of multiple systems. More specifically, we derive the probability that a large body is a member of a binary with semi-major axis of order a. The probability depends upon sigma, the total surface density, Sigma, the surface density of large bodies having radius R, and theta=10^-4, t...

  6. Evaporative Instability in Binary Mixtures

    Science.gov (United States)

    Narayanan, Ranga; Uguz, Erdem

    2012-11-01

    In this talk we depict the physics of evaporative convection for binary systems in the presence of surface tension gradient effects. Two results are of importance. The first is that a binary system, in the absence of gravity, can generate an instability only when heated from the vapor side. This is to be contrasted with the case of a single component where instability can occur only when heated from the liquid side. The second result is that a binary system, in the presence of gravity, will generate an instability when heated from either the vapor or the liquid side provided the heating is strong enough. In addition to these results we show the conditions at which interfacial patterns can occur. Support from NSF OISE 0968313, Partner Univ. Fund and a Chateaubriand Fellowship is acknowledged.

  7. Marangoni Convection in Binary Mixtures

    CERN Document Server

    Zhang, J; Oron, A; Behringer, Robert P.; Oron, Alexander; Zhang, Jie

    2006-01-01

    Marangoni instabilities in binary mixtures are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of sodium chloride/water, we have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadowgraph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stage and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes i...

  8. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  9. Black Hole Binaries in Quiescence

    CERN Document Server

    Bailyn, Charles D

    2016-01-01

    I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in the optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-rary binaries, which has taken on a new importance in the era of gravitational wave astronomy.

  10. Practical Binary Adaptive Block Coder

    CERN Document Server

    Reznik, Yuriy A

    2007-01-01

    This paper describes design of a low-complexity algorithm for adaptive encoding/ decoding of binary sequences produced by memoryless sources. The algorithm implements universal block codes constructed for a set of contexts identified by the numbers of non-zero bits in previous bits in a sequence. We derive a precise formula for asymptotic redundancy of such codes, which refines previous well-known estimate by Krichevsky and Trofimov, and provide experimental verification of this result. In our experimental study we also compare our implementation with existing binary adaptive encoders, such as JBIG's Q-coder, and MPEG AVC (ITU-T H.264)'s CABAC algorithms.

  11. Statistical Study of Visual Binaries

    CERN Document Server

    Abdel-Rahman, H I; Elsanhoury, W H

    2016-01-01

    In this paper, some statistical distributions of wide pairs included in Double Star Catalogue are investigated. Frequency distributions and testing hypothesis are derived for some basic parameters of visual binaries. The results reached indicate that, it was found that the magnitude difference is distributed exponentially, which means that the majority of the component of the selected systems is of the same spectral type. The distribution of the mass ratios is concentrated about 0.7 which agree with Salpeter mass function. The distribution of the linear separation appears to be exponentially, which contradict with previous studies for close binaries.

  12. The Exoplanet Simple Orbit Fitting Toolbox (ExoSOFT): An Open-source Tool for Efficient Fitting of Astrometric and Radial Velocity Data

    Science.gov (United States)

    Mede, Kyle; Brandt, Timothy D.

    2017-03-01

    We present the Exoplanet Simple Orbit Fitting Toolbox (ExoSOFT), a new, open-source suite to fit the orbital elements of planetary or stellar-mass companions to any combination of radial velocity and astrometric data. To explore the parameter space of Keplerian models, ExoSOFT may be operated with its own multistage sampling approach or interfaced with third-party tools such as emcee. In addition, ExoSOFT is packaged with a collection of post-processing tools to analyze and summarize the results. Although only a few systems have been observed with both radial velocity and direct imaging techniques, this number will increase, thanks to upcoming spacecraft and ground-based surveys. Providing both forms of data enables simultaneous fitting that can help break degeneracies in the orbital elements that arise when only one data type is available. The dynamical mass estimates this approach can produce are important when investigating the formation mechanisms and subsequent evolution of substellar companions. ExoSOFT was verified through fitting to artificial data and was implemented using the Python and Cython programming languages; it is available for public download at https://github.com/kylemede/ExoSOFT under GNU General Public License v3.

  13. The hard quiescent spectrum of the neutron-star X-ray transient EXO 1745-248 in the globular cluster Terzan 5

    CERN Document Server

    Wijnands, R; Pooley, D; Edmonds, P D; Lewin, W H G; Grindlay, J E; Jonker, P G; Miller, J M; Wijnands, Rudy; Heinke, Craig O.; Pooley, David; Edmonds, Peter D.; Lewin, Walter H. G.; Grindlay, Jonathan E.; Jonker, Peter G.; Miller, Jon M.

    2003-01-01

    We present a Chandra observation of the globular cluster Terzan 5 during times when the neutron-star X-ray transient EXO 1745-248 located in this cluster was in its quiescent state. We detected the quiescent system with a (0.5-10 keV) luminosity of ~2 x 10^{33} ergs/s. This is similar to several other neutron-star transients observed in their quiescent states. However, the quiescent X-ray spectrum of EXO 1745--48 was dominated by a hard power-law component instead of the soft component that usually dominates the quiescent emission of other neutron-star X-ray transients. This soft component could not conclusively be detected in EXO 1745-248 and we conclude that it contributed at most 10% of the quiescent flux in the energy range 0.5-10 keV. EXO 1745-248 is only the second neutron-star transient whose quiescent spectrum is dominated by the hard component (SAX J1808.4-3658 is the other one). We discuss possible explanations for this unusual behavior of EXO 1745-248, its relationship to other quiescent neutron-st...

  14. KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

    Energy Technology Data Exchange (ETDEWEB)

    Gies, D. R.; Matson, R. A.; Guo, Z.; Lester, K. V. [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States); Orosz, J. A. [Department of Astronomy, San Diego State University, San Diego, CA 92182-1221 (United States); Peters, G. J., E-mail: gies@chara.gsu.edu, E-mail: rmatson@chara.gsu.edu, E-mail: guo@chara.gsu.edu, E-mail: lester@chara.gsu.edu, E-mail: jorosz@mail.sdsu.edu, E-mail: gjpeters@mucen.usc.edu [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States)

    2015-12-15

    Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

  15. Binary/BCD-to-ASCII data converter

    Science.gov (United States)

    Miller, A. J.

    1977-01-01

    Converter inputs multiple precision binary words, converts data to multiple precision binary-coded decimal, and routes data back to computer. Converter base can be readily changed without need for new gate structure for each base changeover.

  16. Binary stars in the RAVE survey

    Directory of Open Access Journals (Sweden)

    Zwitter T.

    2012-02-01

    Full Text Available We searched the sample of RAVE survey spectra for both types of spectroscopic binary stars in order to estimate their number in the sample and perform a study on newly discovered binaries.

  17. Indicators and Methods to Understand Past Environments from ExoMars Rover Drills

    Science.gov (United States)

    Kereszturi, A.; Bradak, B.; Chatzitheodoridis, E.; Ujvari, G.

    2016-03-01

    Great advances are expected during the analysis of drilled material acquired from 2 m depth by ExoMars rover, supported by the comparison to local context, and the joint use of different instruments. Textural information might be less detailed relatively to what is usually obtained at outcrops during classical geological field work on the Earth, partly because of the lack of optical imaging of the borehole wall and also because the collected samples are crushed. However sub-mm scale layering and some other sedimentary features might be identified in the borehole wall observations, or in the collected sample prior to crushing, and also at nearby outcrops. The candidate landing sites provide different targets and focus for research: Oxia Planum requires analysis of phyllosilicates and OH content, at Mawrth Vallis the layering of various phyllosilicates and the role of shallow-subsurface leaching should be emphasized. At Aram Dorsum the particle size and fluvial sedimentary features will be interesting. Hydrated perchlorates and sulphates are ideal targets possibly at every landing sites because of OH retention, especially if they are mixed with smectites, thus could point to even ancient wet periods. Extensive use of information from the infrared wall scanning will be complemented for geological context by orbital and rover imaging of nearby outcrops. Information from the context is especially useful to infer the possible action of past H2O. Separation of the ice and liquid water effects will be supported by cation abundance and sedimentary context. Shape of grains also helps here, and composition of transported grains points to the weathering potential of the environment in general. The work on Mars during the drilling and sample analysis will provide brand new experience and knowledge for future missions.

  18. NOMAD on ExoMars: first results from near Earth commissioning and mid-cruise checking

    Science.gov (United States)

    Vandaele, Ann C.; Neefs, Eddy; Ristic, Bojan; Thomas, Ian R.; Mason, Jon; Patel, Manish; Lopez-Moreno, Jose-Juan; Bellucci, Giancarlo; NOMAD Team

    2016-10-01

    NOMAD (Nadir and Occultation for MArs Discovery) is a suite of three high-resolution spectrometers on-board the ExoMars Trace Gas Orbiter. The instrument will be able to detect and map a wide variety of Martian gases in unprecedented detail. NOMAD covers the UV-visible (UVIS channel - 200-650nm) and infrared ranges (SO and LNO channels - 2.2-4.3mm), operating in solar occultation, limb and nadir-viewing modes, generating a huge dataset of Martian atmospheric observations during the mission across a wide spectral range.NOMAD has the resolving power to identify many trace gases that exhibit absorption features within the spectral range of the three channels. The order-of-magnitude increase in spectral resolution over previous instruments will enable spatial and temporal mapping of several isotopologues of methane and water, providing important measurements of the Martian D/H and methane isotope ratios globally. Sensitivity studies have shown that, using expected SNR values, NOMAD should have the ability to measure methane concentrations down to 25 parts per trillion (ppt) in solar occultation mode, and to 11 parts per billion (ppb) in nadir mode. Using SO and LNO in combination with UVIS, aerosol properties such as optical depth, composition and size distribution can also be derived. NOMAD will also continue to monitor the major seasonal cycles on Mars, extending existing datasets made by successive space missions in the past decade.NOMAD is now en route to Mars, and has already performed a series of observations, primarily to check the health of the instrument and to begin calibration.

  19. Demonstration Of Synthetic Exo-earth Detection In The Lab With Speckle Subtraction Techniques

    Science.gov (United States)

    Belikov, Ruslan; Give'on, A.; Savransky, D.; Pueyo, L.; Kern, B.; Kasdin, J.

    2007-12-01

    The problem of detecting and imaging earth-like exoplanets is hampered by the fact that wavefront error in the optics of a space telescope creates a speckle pattern that can swamp the exoplanet. The standard approach for dealing with speckles is to suppress them below the planet level by a deformable mirror using a wavefront control algorithm. However, such wavefront control may take a long time to achieve speckle suppression of 1010, the nominal contrast necessary for exo-earths, especially if the target star is dim. Furthermore, a very precise deformable mirror and electronics are required. In this paper, we present and demonstrate in the lab a method to detect planet light from amidst a brighter speckle pattern (as long as that pattern is stable), thus relaxing the requirement of 1010 speckle suppression. Furthermore, our detection is simultaneous with wavefront control and uses all the images taken in the course of wavefront control, saving valuable mission time. The method consists of (a) using the wavefront control estimate of the coherent speckle field to separate the speckles from the incoherent planet light, and (b) using a matched filter to reduce noise. No motion or rotation of the telescope is required for this method. The experiment was conducted on the High Contrast Imaging Testbed at the Jet Propulsion Lab using the Shaped Pupil coronagraph under 10% optical bandwidth. This work was funded in part by JPL contract 1254357 and the Michelson Science Center, and carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  20. M-DLS multichannel diode laser spectrometer for ExoMars landing platform

    Science.gov (United States)

    Rodin, A.; Vinogradov, I.; Klimchuk, A., Sr.

    2014-12-01

    A multichannel laser diode laser spectrometer has been proposed as a part of scientific payload onboard Russian landing platform of the ExoMars-2018 mission. Scientific goals of the experiment include precise analysis of chemical and isotopic composition, thermal and dynamical structure of the ambient atmosphere, as well as volatiles in soil samples retrieved in the vicinity of the platform, and their diurnal and seasonal variation during at least one Martian year. The instrument consists of three optical paths and two spectral channels. Optical paths corresponding to a classical laser spectroscopy are organized in high-temperature cell for soil volatiles analysis, and multipass integrated cavity-output spectroscopy (ICOS) cell with an efficient pathlength reaching several km. The third optical path is organized in the free atmosphere by direct Sun observations with heterodyne technique. The latter method allows to retrieve vertical profiles of the observed species and to estimate wind speed profile by Doppler shift of absorption line.The instrument covers two major spectral ranges; near infrared (1.39-1.65 micron) and mid-infrared (2.67-3.27 micron). In the near-infrared range main CO2 and H2O isotopes are analyzed, including vertical profiling of H2O and winds. In the mid-infrared, the instrument will detect HDO and methane. An unprecedented accuracy corresponding to upper limit of 70 ppt is expected on CH4 in both ICOS and heterodyne channels.The instrument is characterized by high degree of redundancy and implements numerous innovative solution, such as fiber optical tract, single mode waveguides for heterodyning of the IR radiation, microoptical system for Sun tracking etc. It is envisioned that M-TDLAS will become the first spacecraft application of ICOS and infrared heterodyning techniques, and will provide qualitatively new knowledge about the structure, composition and dynamics of the lower atmosphere of Mars.

  1. Indicators and Methods to Understand Past Environments from ExoMars Rover Drills

    Science.gov (United States)

    Kereszturi, A.; Bradak, B.; Chatzitheodoridis, E.; Ujvari, G.

    2016-11-01

    Great advances are expected during the analysis of drilled material acquired from 2 m depth by ExoMars rover, supported by the comparison to local context, and the joint use of different instruments. Textural information might be less detailed relatively to what is usually obtained at outcrops during classical geological field work on the Earth, partly because of the lack of optical imaging of the borehole wall and also because the collected samples are crushed. However sub-mm scale layering and some other sedimentary features might be identified in the borehole wall observations, or in the collected sample prior to crushing, and also at nearby outcrops. The candidate landing sites provide different targets and focus for research: Oxia Planum requires analysis of phyllosilicates and OH content, at Mawrth Vallis the layering of various phyllosilicates and the role of shallow-subsurface leaching should be emphasized. At Aram Dorsum the particle size and fluvial sedimentary features will be interesting. Hydrated perchlorates and sulphates are ideal targets possibly at every landing sites because of OH retention, especially if they are mixed with smectites, thus could point to even ancient wet periods. Extensive use of information from the infrared wall scanning will be complemented for geological context by orbital and rover imaging of nearby outcrops. Information from the context is especially useful to infer the possible action of past H2O. Separation of the ice and liquid water effects will be supported by cation abundance and sedimentary context. Shape of grains also helps here, and composition of transported grains points to the weathering potential of the environment in general. The work on Mars during the drilling and sample analysis will provide brand new experience and knowledge for future missions.

  2. Fast and Accurate Radiative Transfer Calculations Using Principal Component Analysis for (Exo-)Planetary Retrieval Models

    Science.gov (United States)

    Kopparla, P.; Natraj, V.; Shia, R. L.; Spurr, R. J. D.; Crisp, D.; Yung, Y. L.

    2015-12-01

    Radiative transfer (RT) computations form the engine of atmospheric retrieval codes. However, full treatment of RT processes is computationally expensive, prompting usage of two-stream approximations in current exoplanetary atmospheric retrieval codes [Line et al., 2013]. Natraj et al. [2005, 2010] and Spurr and Natraj [2013] demonstrated the ability of a technique using principal component analysis (PCA) to speed up RT computations. In the PCA method for RT performance enhancement, empirical orthogonal functions are developed for binned sets of inherent optical properties that possess some redundancy; costly multiple-scattering RT calculations are only done for those few optical states corresponding to the most important principal components, and correction factors are applied to approximate radiation fields. Kopparla et al. [2015, in preparation] extended the PCA method to a broadband spectral region from the ultraviolet to the shortwave infrared (0.3-3 micron), accounting for major gas absorptions in this region. Here, we apply the PCA method to a some typical (exo-)planetary retrieval problems. Comparisons between the new model, called Universal Principal Component Analysis Radiative Transfer (UPCART) model, two-stream models and line-by-line RT models are performed, for spectral radiances, spectral fluxes and broadband fluxes. Each of these are calculated at the top of the atmosphere for several scenarios with varying aerosol types, extinction and scattering optical depth profiles, and stellar and viewing geometries. We demonstrate that very accurate radiance and flux estimates can be obtained, with better than 1% accuracy in all spectral regions and better than 0.1% in most cases, as compared to a numerically exact line-by-line RT model. The accuracy is enhanced when the results are convolved to typical instrument resolutions. The operational speed and accuracy of UPCART can be further improved by optimizing binning schemes and parallelizing the codes, work

  3. Exo-Mercury Analogues and the Roche Limit for Close-Orbiting Rocky Planets

    Science.gov (United States)

    Rogers, Leslie A.; Price, Ellen

    2015-12-01

    The origin of Mercury's enhanced iron content is a matter of ongoing debate. The characterization of rocky exoplanets promises to provide new independent insights on this topic, by constraining the occurrence rate and physical and orbital properties of iron-enhanced planets orbiting distant stars. The ultra-short-period transiting planet candidate KOI-1843.03 (0.6 Earth-radius, 4.245 hour orbital period, 0.46 Solar-mass host star) represents the first exo-Mercury planet candidate ever identified. For KOI-1843.03 to have avoided tidal disruption on such a short orbit, Rappaport et al. (2013) estimate that it must have a mean density of at least 7g/cc and be at least as iron rich as Mercury. This density lower-limit, however, relies upon interpolating the Roche limits of single-component polytrope models, which do not accurately capture the density profiles of >1000 km differentiated rocky bodies. A more exact calculation of the Roche limit for the case of rocky planets of arbitrary composition and central concentration is needed. We present 3D interior structure simulations of ultra-short-period tidally distorted rocky exoplanets, calculated using a modified version of Hachisu’s self-consistent field method and realistic equations of state for silicates and iron. We derive the Roche limits of rocky planets as a function of mass and composition, and refine the composition constraints on KOI-1843.03. We conclude by discussing the implications of our simulations for the eventual characterization of short-period transiting planets discovered by K2, TESS, CHEOPS and PLATO.

  4. Bayesian analysis of binary sequences

    Science.gov (United States)

    Torney, David C.

    2005-03-01

    This manuscript details Bayesian methodology for "learning by example", with binary n-sequences encoding the objects under consideration. Priors prove influential; conformable priors are described. Laplace approximation of Bayes integrals yields posterior likelihoods for all n-sequences. This involves the optimization of a definite function over a convex domain--efficiently effectuated by the sequential application of the quadratic program.

  5. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, Ivan I., E-mail: iis@gao.spb.ru [Pulkovo Observatory of the Russian Academy of Sciences, Pulkovskoje ave. 65, St. Petersburg 196140 (Russian Federation)

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  6. A Galactic Binary Detection Pipeline

    Science.gov (United States)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  7. The Meritfactor of Binary Seqences

    DEFF Research Database (Denmark)

    Høholdt, Tom

    1999-01-01

    Binary sequences with small aperiodic correlations play an important role in many applications ranging from radar to modulation and testing of systems. Golay(1977) introduced the merit factor as a measure of the goodness of the sequence and conjectured an upper bound for this. His conjecture is s...

  8. Eccentricity distribution of wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+-0.02 and the eccentricity distribution can be modeled as f(e) ~= 1.2 e + 0.4. However, wide binaries containing inner subsystems, i.e. triple or higher-order multiples, have significantly smaller eccentricities with the average e = 0.52+-0.05 and the peak at e ~ 0.5. We find that the catalog of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentr...

  9. Demonstration of the ExoMars sample preparation and distribution system jointly with an optical instrument head

    Science.gov (United States)

    Schulte, Wolfgang; Thiele, Hans; Hofmann, Peter; Baglioni, Pietro

    The ExoMars program will search for past and present life on Mars. ExoMars will address important scientific goals and demonstrate key in-situ enabling technologies. Among such technologies are the acquisition, preparation, distribution and analysis of samples from Mars surface rocks and from the subsurface. The 2018 mission will land an ESA rover on Mars which carries a sample preparation and distribution system (SPDS) and a suite of analytical instruments, the Pasteur Payload with its Analytical Laboratory Drawer (ALD). Kayser-Threde GmbH (Germany) will be responsible for the SPDS as a subcontractor under the mission prime Thales Alenia Space. The SPDS comprises a number of complex mechanisms and mechanical devices designed to transport drill core samples within the rover analytical laboratory, to crush them to powder with a fine grain size, to portion discrete amounts of powdered sample material, to distribute and fill the material into sample containers and to prepare flat sample surfaces for scientific analysis. Breadboards of the crushing mechanism, the dosing mechanism and a distribution carousel with sample containers and a powder sample surface flattening mechanism were built and tested. Kayser-Threde, as a member of the Spanish led ExoMars Raman Instrument team, is also responsible for development of the Raman optical head, which will be mounted inside ALD and will inspect the crushed samples, when they are presented to the instrument by the distribution carousel. Within this activity, which is performed under contract with the Institute of Physical Chemistry of the University of Jena (Germany) and funded by the German DLR, Kayser-Threde can demonstrate Raman measurements with the optical head and a COTS laser and spectrometer and thus simulate the full Raman instrument optical path. An autofocus system with actuator and feedback optics is also part of this activity, which allows focusing the 50 m Raman spot on the surface of the powdered sample

  10. Coevolution of binaries and circumbinary gaseous discs

    Science.gov (United States)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  11. Formation and evolution of compact binaries

    NARCIS (Netherlands)

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  12. Comprehensive wide-band magnitudes and albedos for the planets, with applications to exo-planets and Planet Nine

    Science.gov (United States)

    Mallama, Anthony; Krobusek, Bruce; Pavlov, Hristo

    2017-01-01

    Complete sets of reference magnitudes in all 7 Johnson-Cousins bands (U, B, V, R, I, RC and IC) and the 5 principal Sloan bands (u', g', r', i', and z') are presented for the 8 planets. These data are accompanied by illumination phase functions and other formulas which characterize the instantaneous brightness of the planets. The main source of Johnson-Cousins magnitudes is a series of individualized photometric studies reported in recent years. Gaps in that dataset were filled with magnitudes synthesized in this study from published spectrophotometry. The planetary Sloan magnitudes, which are established here for the first time, are an average of newly recorded Sloan filter photometry, synthetic magnitudes and values transformed from the Johnson-Cousins system. Geometric albedos derived from these two sets of magnitudes are consistent within each photometric system and between the systems for all planets and in all bands. This consistency validates the albedos themselves as well as the magnitudes from which they were derived. In addition, a quantity termed the delta stellar magnitude is introduced to indicate the difference between the magnitude of a planet and that of its parent star. A table of these delta values for exo-planets possessing a range of physical characteristics is presented. The delta magnitudes are for phase angle 90° where a planet is near the greatest apparent separation from its star. This quantity may be useful in exo-planet detection and observation strategies when an estimate of the signal-to-noise ratio is needed. Likewise, the phase curves presented in this paper can be used for characterizing exo-planets. Finally, magnitudes for the proposed Planet Nine are estimated, and we note that P9 may be especially faint at red and near-IR wavelengths.

  13. The DREAMS payload on-board the Entry and descent Demonstrator Module of the ExoMars mission

    Science.gov (United States)

    Esposito, F.; Montmessin, F.; Debei, S.; Colombatti, G.; Harri, A.-M.; Pommereau, J.-P.; Wilson, C.; Aboudan, A.; Molfese, C.; Zaccariotto, M.; Mugnuolo, R.

    2012-04-01

    DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) is the scientific payload selected by ESA and NASA for the accommodation on the Entry and descent Demonstrator Module (EDM) of the ExoMars mission to be launched in 2016. It is a meteorological station with the additional capability to perform measurements of the electric fields close to the surface of Mars. It is an autonomous system that includes its own battery for power supply. It is constituted by the following subsystems: MarsTem (thermometer), MetBaro (pressure sensor), MetHumi (humidity sensor), MetWind (2-D wind sensor), MicroARES (electric field sensor), ODS (optical depth sensor), a triaxial accelerometer (for attitude measurements), a CEU (Central Electronic Unit) and a battery. All systems in DREAMS have a solid heritage from other missions and have very high TRL. The ExoMars 2016 EDM mission is foreseen to reach Mars during the climatological dust storm season. DREAMS will have the unique chance of making scientific measurements able to characterize the martian environment in this dust loaded scenario. Even with low resources (volume, mass, energy) DREAMS will be able to perform novel measurements that will improve our understanding of the martian environment and dust cycle. DREAMS will perform: • Meteorological measurements by monitoring pressure, temperature, wind speed and direction, humidity and dust opacity during a martian sol at its landing site. • Characterization of the martian boundary layer. • Hazard monitoring by providing a comprehensive dataset to help engineers to quantify hazards for equipments and human crew: velocity of windblown dust, electrostatic charging, existence of discharges, and electromagnetic noise potentially affecting communications. • The first ever investigation of atmospheric electric phenomena on Mars. The DREAMS experiment gathers a wide consortium of institutions led by Italy, reflecting the current involvement

  14. Endo-Exo Circulation as a Paradigm of Life: Towards a New Synthesis of Eastern Philosophy and Western Science

    Science.gov (United States)

    Murase, M.

    What is life? Despite the advanced studies of Western scienceand the progress of modern technology, we have not yet answered this problem satisfactorily. What is worse, it is a double problem that we cannot realize how we are deeply influenced by the traditional way of Western thinking in attacking the above problem. Owing to the dichotomy of subject (or endo) and object (or exo), together with its corresponding reductionism, we have specified more and more the detailed components of a living system and have also required the reproducibility principle that the living system shows the same responses to the same stimuli under the same conditions. A dichotomy perspective of this kind, which has been central to modern science, stands on the assumption that opposites are mutually exclusive and even contradictory. Contrary to this dichotomy perspective, there is an alternative complementarity perspective typical of Eastern philosophy, which is surprisingly similar to Niels Bohr' s complementarity principle in modern physics. It actually suggests that opposites are not mutually exclusive, but merely complementary to one another, because opposites are thought to be only different aspects of the same wholeness. This means that there is no clear distinction between subject (endo) and object (exo). As there is no definitely isolated object, the reproducibility principle is mostly violated. We must therefore pay much attention to the transients --- or processes --- during the past history of life. On the basis of this complementarity idea, we are encouraged to have a holistic view by integrating fragments of knowledge at various component levels and time scales when investigating the history of life. In this sense, we need a new synthesis of Western science and Eastern philosophy, instead of considering either of them separately. Only then, it is possible to attack the long-standing question: what is life? Along these lines, in the present paper, a proces s of endo-exo

  15. Exo-Arabinanase of Penicillium chrysogenum Able To Release Arabinobiose from α-1,5-l-Arabinan

    OpenAIRE

    Sakamoto, Tatsuji; Thibault, Jean-François

    2001-01-01

    An exo-arabinanase, designated Abnx, was purified from a culture filtrate of Penicillium chrysogenum 31B by ammonium sulfate precipitation, anion-exchange chromatography, and hydrophobic chromatography. Abnx had an apparent molecular mass of 47 kDa. The enzyme released only arabinobiose from the nonreducing terminus of α-1,5-l-arabinan and showed no activity towards p-nitrophenyl-α-l-arabinofuranoside and α-1,5-l-arabinofuranobiose. Abnx is the first enzyme with this mode of action.

  16. A Dual Source Ion Trap Mass Spectrometer for the Mars Organic Molecule Analyzer of ExoMars 2018

    Science.gov (United States)

    Brickerhoff, William B.; vanAmerom, F. H. W.; Danell, R. M.; Arevalo, R.; Atanassova, M.; Hovmand, L.; Mahaffy, P. R.; Cotter, R. J.

    2011-01-01

    We present details on the objectives, requirements, design and operational approach of the core mass spectrometer of the Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars mission. The MOMA mass spectrometer enables the investigation to fulfill its objective of analyzing the chemical composition of organic compounds in solid samples obtained from the near surface of Mars. Two methods of ionization are realized, associated with different modes of MOMA operation, in a single compact ion trap mass spectrometer. The stringent mass and power constraints of the mission have led to features such as low voltage and low frequency RF operation [1] and pulse counting detection.

  17. Search for Majoron-emitting modes of double-beta decay of $^{136}$Xe with EXO-200

    CERN Document Server

    :,; Auty, D J; Barbeau, P S; Beauchamp, E; Beck, D; Belov, V; Benitez-Medina, C; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Chaves, J; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; DeVoe, R; Delaquis, S; Didberidze, T; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Hall, C; Herrin, S; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; Odian, A; Ostrovskiy, I; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Rivas, A; Rowson, P C; Rozo, M P; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tosi, D; Tsang, R; Twelker, K; Vogel, P; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2014-01-01

    EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of $^{136}$Xe. Here we report on a search for various Majoron-emitting modes based on 100 kg$\\cdot$yr exposure of $^{136}$Xe. A lower limit of $T^{^{136}Xe}_{1/2} >1.2...10^{24}$ yr at 90% C.L. on the half-life of the spectral index = 1 Majoron decay was obtained, corresponding to a constraint on the Majoron-neutrino coupling constant of $||<$ (0.8-1.7)...10$^{-5}$.

  18. Gravitational Microlensing of Binary and Binary and Multiple Stars

    Science.gov (United States)

    Cherepashchuk, A. M.

    1995-08-01

    Recent observations of the effect of microlensing of stars of large Magellanic Clouds by dark bodies of Galactic Halo have led to the discovery of new population in our galaxy - dark bodies with amsses ~ 0.1 M(sun). As a consequence, astronomers have gained a unique possibility of using gravitational microlensing as an effective extraterestrial telescope with extremely high angular resolution. Application of this to binary stars is discussed. of particular interest is to apply microlensing to search for planetary stars . Planets and stars move about the center of gravity of the system , so the appaarent motion of a star in nonuniform and the light curve is asymetrical and colour dependent. This allows to determin basic parameters of binary system

  19. Permutation Entropy for Random Binary Sequences

    Directory of Open Access Journals (Sweden)

    Lingfeng Liu

    2015-12-01

    Full Text Available In this paper, we generalize the permutation entropy (PE measure to binary sequences, which is based on Shannon’s entropy, and theoretically analyze this measure for random binary sequences. We deduce the theoretical value of PE for random binary sequences, which can be used to measure the randomness of binary sequences. We also reveal the relationship between this PE measure with other randomness measures, such as Shannon’s entropy and Lempel–Ziv complexity. The results show that PE is consistent with these two measures. Furthermore, we use PE as one of the randomness measures to evaluate the randomness of chaotic binary sequences.

  20. Transiting exoplanets from the CoRoT space mission III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS

    CERN Document Server

    Bouchy, F; Deleuil, M; Loeillet, B; Hatzes, A P; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Benz, W; Bordé, P; Deeg, H J; De la Reza, R; Dvorak, R; Erikson, A; Fridlund, M; Gondoin, P; Guillot, T; Hébrard, G; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Mayor, M; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Pont, F; Rauer, H; Rouan, D; Schneider, J; Triaud, A H M J; Udry, S; Wuchterl, G

    2008-01-01

    We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda=7.2+-4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented.

  1. Populating the Galaxy with close Be binaries

    CERN Document Server

    Kiel, P D; Murray, J R; Hayasaki, K

    2007-01-01

    Be/X-ray binaries comprise roughly two-thirds of the high-mass X-ray binaries (HMXBs), which is a class of X-ray binaries that results from the high mass of the companion or donor star (> 10 solar masses). Currently the formation and evolution of X-ray producing Be binaries is a matter of great debate. Modelling of these systems requires knowledge of Be star evolution and also consideration of how the evolution changes when the star is in close proximity to a companion. Within this work we complete a full population synthesis study of Be binaries for the Galaxy. The results for the first time match aspects of the observational data, most notably the observed upper limit to the period distribution. We conclude that greater detailed studies on the evolution of Be stars within X-ray binaries needs to be completed, so that rapid binary evolution population synthesis packages may best evolve these systems.

  2. Close supermassive binary black holes

    Science.gov (United States)

    Gaskell, C. Martin

    2010-01-01

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive blackhole binary (SMB). The AGN J1536+0441 (=SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that 1536+044 is an example of line emission from a disc. If this is correct, the lack of clear optical spectral evidence for close SMBs is significant and argues either that the merging of close SMBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  3. Desktop setup for binary holograms

    Science.gov (United States)

    Ginter, Olaf; Rothe, Hendrik

    1996-08-01

    Binary gratings as holograms itself or as photographic masking tools for further fabrication steps can fulfill a lot of applications. The commonly used semiconductor technologies for direct writing of high resolution structures are often too expensive. On the other hand computer plots at a reasonable price with photographic reduction do not meet the needs of precision e.g. for interferometric inspection. The lack of cheap and reliable instruments for direct writing in an appropriate resolution is still a problem in fabricating synthetic holograms. Using off-the-shelf components a direct writing plotter for binary patterns can be built at moderate costs. Typical design rules as well as experimental results are given and the final setup is introduced.

  4. Slim Sets of Binary Trees

    CERN Document Server

    Grünewald, Stefan

    2010-01-01

    A classical problem in phylogenetic tree analysis is to decide whether there is a phylogenetic tree $T$ that contains all information of a given collection $\\cP$ of phylogenetic trees. If the answer is "yes" we say that $\\cP$ is compatible and $T$ displays $\\cP$. This decision problem is NP-complete even if all input trees are quartets, that is binary trees with exactly four leaves. In this paper, we prove a sufficient condition for a set of binary phylogenetic trees to be compatible. That result is used to give a short and self-contained proof of the known characterization of quartet sets of minimal cardinality which are displayed by a unique phylogenetic tree.

  5. Mass transfer between binary stars

    Science.gov (United States)

    Modisette, J. L.; Kondo, Y.

    1980-01-01

    The transfer of mass from one component of a binary system to another by mass ejection is analyzed through a stellar wind mechanism, using a model which integrates the equations of motion, including the energy equation, with an initial static atmosphere and various temperature fluctuations imposed at the base of the star's corona. The model is applied to several situations and the energy flow is calculated along the line of centers between the two binary components, in the rotating frame of the system, thereby incorporating the centrifugal force. It is shown that relatively small disturbances in the lower chromosphere or photosphere can produce mass loss through a stellar wind mechanism, due to the amplification of the disturbance propagating into the thinner atmosphere. Since there are many possible sources of the disturbance, the model can be used to explain many mass ejection phenomena.

  6. The WISDOM Radar onboard the Rover of the ExoMars mission (Invited)

    Science.gov (United States)

    Ciarletti, V.; Corbel, C.; Plettemeier, D.; Clifford, S. M.; Cais, P.; Hamran, S.

    2009-12-01

    The most fundamental and basic aspect of the geologic characterization of any environment is understanding its stratigraphy and structure - which provides invaluable insights into its origin, the processes and events by which it evolved, and (through the examination of superpositional and cross-cutting relationships) their relative timing. The WISDOM GPR onboard the Rover of the ESA ExoMars mission (2016) has the ability to investigate and characterize the nature of the subsurface remotely, providing high-resolution (several cm-scale) data on subsurface stratigraphy, structure, and the magnitude and scale of spatial heterogeneity, to depths in excess of 3 m. Unlike traditional imaging systems or spectrometers, which are limited to characterization of the visible surface, WISDOM can access what lies beneath - providing an understanding of the 3-dimensional geologic context of the landing site along the Rover path. WISDOM will address a variety of high-priority scientific objectives: (1) Understand the geology and geologic evolution of the landing site, including local lithology, stratigraphy and structure. (2) Characterize the 3-D electromagnetic properties of the Landing Site - including the scale and magnitude of spatial heterogeneity - for comparison with those measured at larger scales by MARSIS, SHARAD and any future orbital radars. (3) Understand the local distribution and state of shallow subsurface H2O and other volatiles, including the potential presence of segregated ground ice (as ice lenses and wedges), the persistent or transient occurrence of liquid water/brine, and deposits of methane hydrate and (4) identify the most promising locations for drilling that combine targets of high scientific interest. In addition to these objectives, there are also clear scientific and operational benefits when WISDOM is operated in concert with the rover’s drill and its associated analytical instruments, which will determine the compositional and physical properties

  7. GIV/Girdin binds Exocyst subunit-Exo70 and Regulates Exocytosis of GLUT4 Storage Vesicles

    Science.gov (United States)

    Lopez-Sanchez, Inmaculada; Ma, Gary S.; Pedram, Shabnam; Kalogriopoulos, Nicholas; Ghosh, Pradipta

    2015-01-01

    Insulin resistance (IR) is a metabolic disorder characterized by impaired glucose uptake in response to insulin. The current paradigm for insulin signaling centers upon the insulin receptor (InsR) and its substrate IRS1; the latter is believed to be the chief conduit for post-receptor signaling. We recently demonstrated that GIV, a Guanidine Exchange Factor (GEF) for the trimeric G protein, Gαi, is a major hierarchical conduit for the metabolic insulin response. By virtue of its ability to directly bind the InsR, IRS1 and PI3K, GIV enhances the InsR-IRS1-Akt-AS160 (RabGAP) signaling cascade and cellular glucose uptake via its GEF function. Phosphoinhibition of GIV-GEF by the fatty-acid/PKCθ pathway inhibits the cascade and impairs glucose uptake. Here we show that GIV directly and constitutively binds the exocyst complex subunit Exo-70 and also associates with GLUT4-storage vesicles (GSVs) exclusively upon insulin stimulation. Without GIV or its GEF function, membrane association of Exo-70 as well as exocytosis of GSVs in response to insulin are impaired. Thus, GIV is an essential upstream component within the insulin signaling cascade that couples components within the InsR and G-Protein signaling cascade to those within the exocytic pathway. These findings suggest a role of GIV in coordinating the signaling and trafficking events of metabolic insulin response. PMID:26514725

  8. The Structural Basis of Substrate Recognition in an exo-b-d-glucosaminidase Involved in Chitosan Hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Van Bueren, A.; Ghinet, M; Gregg, K; Fleury, A; Brzezinski, R; Boraston, A

    2009-01-01

    Family 2 of the glycoside hydrolase classification is one of the largest families. Structurally characterized members of this family include enzymes with ?-galactosidase activity (Escherichia coli LacZ), ?-glucuronidase activity (Homo sapiens GusB), and ?-mannosidase activity (Bacteroides thetaiotaomicron BtMan2A). Here, we describe the structure of a family 2 glycoside hydrolase, CsxA, from Amycolatopsis orientalis that has exo-?-d-glucosaminidase (exo-chitosanase) activity. Analysis of a product complex (1.85 A resolution) reveals a unique negatively charged pocket that specifically accommodates the nitrogen of nonreducing end glucosamine residues, allowing this enzyme to discriminate between glucose and glucosamine. This also provides structural evidence for the role of E541 as the catalytic nucleophile and D469 as the catalytic acid/base. The structures of an E541A mutant in complex with a natural ?-1,4-d-glucosamine tetrasaccharide substrate and both E541A and D469A mutants in complex with a pNP-?-d-glucosaminide synthetic substrate provide insight into interactions in the + 1 subsite of this enzyme. Overall, a comparison with the active sites of other GH2 enzymes highlights the unique architecture of the CsxA active site, which imparts specificity for its cationic substrate.

  9. The Structural Basis of Substrate Recognition in an exo-beta-d-Glucosaminidase Involved in Chitosan Hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lammerts van Bueren, A.; Ghinet, M; Gregg, K; Fleury, A; Brzezinski, R; Boraston, A

    2009-01-01

    Family 2 of the glycoside hydrolase classification is one of the largest families. Structurally characterized members of this family include enzymes with beta-galactosidase activity (Escherichia coli LacZ), beta-glucuronidase activity (Homo sapiens GusB), and beta-mannosidase activity (Bacteroides thetaiotaomicron BtMan2A). Here, we describe the structure of a family 2 glycoside hydrolase, CsxA, from Amycolatopsis orientalis that has exo-beta-D-glucosaminidase (exo-chitosanase) activity. Analysis of a product complex (1.85 A resolution) reveals a unique negatively charged pocket that specifically accommodates the nitrogen of nonreducing end glucosamine residues, allowing this enzyme to discriminate between glucose and glucosamine. This also provides structural evidence for the role of E541 as the catalytic nucleophile and D469 as the catalytic acid/base. The structures of an E541A mutant in complex with a natural beta-1,4-D-glucosamine tetrasaccharide substrate and both E541A and D469A mutants in complex with a pNP-beta-D-glucosaminide synthetic substrate provide insight into interactions in the +1 subsite of this enzyme. Overall, a comparison with the active sites of other GH2 enzymes highlights the unique architecture of the CsxA active site, which imparts specificity for its cationic substrate.

  10. Crystal structure of a putative exo-β-1,3-galactanase from Bifidobacterium bifidum S17.

    Science.gov (United States)

    Godoy, Andre S; de Lima, Mariana Z T; Camilo, Cesar M; Polikarpov, Igor

    2016-04-01

    Given the current interest in second-generation biofuels, carbohydrate-active enzymes have become the most important tool to overcome the structural recalcitrance of the plant cell wall. While some glycoside hydrolase families have been exhaustively described, others remain poorly characterized, especially with regard to structural information. The family 43 glycoside hydrolases are a diverse group of inverting enzymes; the available structure information on these enzymes is mainly from xylosidases and arabinofuranosidase. Currently, only one structure of an exo-β-1,3-galactanase is available. Here, the production, crystallization and structure determination of a putative exo-β-1,3-galactanase from Bifidobacterium bifidum S17 (BbGal43A) are described. BbGal43A was successfully produced and showed activity towards synthetic galactosides. BbGal43A was subsequently crystallized and data were collected to 1.4 Å resolution. The structure shows a single-domain molecule, differing from known homologues, and crystal contact analysis predicts the formation of a dimer in solution. Further biochemical studies are necessary to elucidate the differences between BbGal43A and its characterized homologues.

  11. Classification with binary gene expressions

    OpenAIRE

    Tuna, Salih; Niranjan, Mahesan

    2009-01-01

    Microarray gene expression measurements are reported, used and archived usually to high numerical precision. However, properties of mRNA molecules, such as their low stability and availability in small copy numbers, and the fact that measurements correspond to a population of cells, rather than a single cell, makes high precision meaningless. Recent work shows that reducing measurement precision leads to very little loss of information, right down to binary levels. In this paper we show how p...

  12. Binary neuron with optical devices

    Science.gov (United States)

    Degeratu, Vasile; Degeratu, Ştefania; Şchiopu, Paul; Şchiopu, Carmen

    2009-01-01

    In this paper the authors present a model of binary neuron, a model of McCulloch-Pitts neuron with optical devices. This model of neuron can be implemented not only in the optic integrated circuits but also in the classic optical circuits it being cheap and immune not only into electromagnetic fields but also into any kind of radiation. The transfer speed of information through the neuron is very higher, it being limited only by the light speed from the received medium.

  13. Be/X-ray binaries

    CERN Document Server

    Reig, Pablo

    2011-01-01

    The purpose of this work is to review the observational properties of Be/X-ray binaries. The open questions in Be/X-ray binaries include those related to the Be star companion, that is, the so-called "Be phenomenon", such as, timescales associated to the formation and dissipation of the equatorial disc, mass-ejection mechanisms, V/R variability, and rotation rates; those related to the neutron star, such as, mass determination, accretion physics, and spin period evolution; but also, those that result from the interaction of the two constituents, such as, disc truncation and mass transfer. Until recently, it was thought that the Be stars' disc was not significantly affected by the neutron star. In this review, I present the observational evidence accumulated in recent years on the interaction between the circumstellar disc and the compact companion. The most obvious effect is the tidal truncation of the disc. As a result, the equatorial discs in Be/X-ray binaries are smaller and denser than those around isolat...

  14. Is primaquine useful and safe as true exo-erythrocytic merontocidal, hypnozoitocidal and gametocidal antimalarial drug?

    Directory of Open Access Journals (Sweden)

    Francisco Javier López-Antuñano

    1999-10-01

    Full Text Available The main objective of this paper is to make available in a single document, a sequence of events that have been published on the biology of malaria parasites and their interaction with the human host, looking for arguments for effective and save treatment: what we know and what we would like to know about the effects of primaquine in order to justify its use in clinical and public health practice. The practicioner should be aware that the antimalarial activity, hemolytic and methemoglobinemic side effects, and detoxification of primaquine are all thought to depend on various biotransformation products of the drug. In spite of the universal use during over six decades, their site and mechanism of formation and degradation and their specific biologic effects remain very poorly understood in human beings. The mature gametocytes of P. falciparum are naturally resistant to chloroquine and other blood merontocides, but they are usually eliminated with a single dose of 1.315 mg/kg per os (p.o. of primaquine phosphate (equivalent to 0.75 mg-base. Rather than empirically, related with relapses frequency, dosage schedules should only be determined through consideration of the kinetics and dynamics of the drug and its effect on sporozoites, pre and exo-erythrocytic merontes, hypnozoites and gametocytes of P. vivax. Where medical care services are not available or not capable to detect glucose -6- phosphate dehydrogenese- (G-6-PD deficiencies and deleterious effects of the drug, we recommend not to use primaquine. Both, P. vivax primary clinical attack and P. vivax relapses, as and when they occur should be treated with a course of 10 mg/kg chloroquine-base p.o. Prevention of relapses is probably related to strain characteristics of P. vivax hypnozoites populations envolved. If well informed and qualified medical care workers decide to use primaquine in the absence of enzime defficiencies and are able to follow-up the clinical, toxicological and parasitic

  15. Russian contribution to ExoMars Trace Gas Orbiter: Atmospheric Chemistry Suite (ACS)

    Science.gov (United States)

    Shakun, Alexey; Korablev, Oleg; Trokhimovskiy, Alexander; Grigoriev, Alexey; Anufreychik, Konstantin; Fedorova, Anna; Ignatiev, Nikolay; Ivanov, Yuriy; Moshkin, Boris; Kalinnikov, Yuriy; Montmessin, Franck

    2016-04-01

    Atmospheric Chemistry Suite (ACS) is a part of science payload of Trace Gas Orbiter (TGO), ExoMars mission. This project developed by European Space Agency (ESA) in collaboration with Russian Space Agency (Roscosmos). Russian contribution to ExoMars TGO is the Proton rocket and two science instruments ACS (three infrared spectrometers) and FREND (neutron detector). ACS consists of three infrared spectrometers (ACS/NIR, ACS/MIR and ACS/TIRVIM) capable to take spectral measurements from near to thermal infrared range simultaneously or separately. Spectrometric channels of ACS share common mechanical, electrical, and thermal interfaces. Electronic box (ACS/BE) provides to spectrometric channels power and data transfer interfaces. SpaceWire link is used for science data transfer and MIL-1553 link - for commanding and housekeeping data transfer. The NIR channel is an echelle spectrometer with acousto-optic tunable filter (AOTF) for the selection of diffraction orders. ACS NIR is capable to perform nadir and occultation observations. NIR covers the spectral range of 0.7-1.7 μm with resolving power of ~25000. NIR will perform unique for TGO instruments nightglow science (searching for O2, OH, NO nightglow emissions on Mars). From the 1.38 μm band NIR will do water vapour mapping in nadir and H2O vertical profiling in solar occultations. High resolution NIR measurements of 1.27 μm O2(a1Δg) dayglow will supply indirect ozone observations on the dayside on nadir. In solar occultation mode, the O2 vertical profiles will be measured from the surface (in case of low dust activity) to the 40 km altitude based on 0.76 μm absorption band. Together with MIR channel in solar occultation NIR will support the measurements of CO2 density profiles (based on 1.43 μm band) and aerosols characterization from 0.7 to 4 μm. The wide spectral range will allow not just determine aerosol particle sizes and density at different altitudes, but also distinguish between dust and ice particles

  16. Visual Binaries in the Orion Nebula Cluster

    CERN Document Server

    Reipurth, Bo; Connelley, Michael S; Bally, John

    2007-01-01

    We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is signifi...

  17. Probing the MSP Prenatal Stage: The Optical Identification of the X-Ray Burster EXO 1745-248 in Terzan 5

    NARCIS (Netherlands)

    Ferraro, F. R.; Pallanca, C.; Lanzoni, B.; Cadelano, M.; Massari, D.; Dalessandro, E.; Mucciarelli, A.

    2015-01-01

    We report on the optical identification of the neutron star burster EXO 1745-248 in Terzan 5. The identification was performed by exploiting Hubble Space Telescope/Advanced Camera for Surveys images acquired in Director's Discretionary Time shortly after (approximately one month) the Swift detection

  18. Quantification of the amount of galacturonic acid residues in blocksequences in pectin homogalacturonan by enzymatic fingerprinting with exo- and endo-polygalacturonase II from Aspergillus niger

    DEFF Research Database (Denmark)

    Limberg, G; Körner, R; Buchholt, H C

    2000-01-01

    A method to determine the amount of galacturonic acid in blocksequence (BS) in pectin homogalacturonan (HG) is described. The method is based on a combination of endopolygalacturonase II (endo-PG II) and exopolygalacturonase (exo-PG) digestion followed by quantification of the liberated galacturo...

  19. Cold DUst around NEarby Stars (DUNES). First results. A resolved exo-Kuiper belt around the solar-like star ζ2 Ret

    NARCIS (Netherlands)

    Eiroa, C.; Fedele, D.; Maldonado, J.; Gonzalez-Garcia, B. M.; Rodmann, J.; Heras, A. M.; Pilbratt, G. L.; Augereau, J. -Ch.; Mora, A.; Montesinos, B.; Ardila, D.; Bryden, G.; Liseau, R.; Stapelfeldt, K.; Launhardt, R.; Solano, E.; Bayo, A.; Absil, O.; Arevalo, M.; Barrado, D.; Beichmann, C.; Danchi, W.; del Burgo, C.; Ertel, S.; Fridlund, M.; Fukagawa, M.; Gutierrez, R.; Gruen, E.; Kamp, I.; Krivov, A.; Lebreton, J.; Loehne, T.; Lorente, R.; Marshall, J.; Martinez-Arnaiz, R.; Meeus, G.; Montes, D.; Morbidelli, A.; Mueller, S.; Mutschke, H.; Nakagawa, T.; Olofsson, G.; Ribas, I.; Roberge, A.; Sanz-Forcada, J.; Thebault, P.; White, G. J.; Wolf, S.; Walker, H.

    2010-01-01

    We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ2 Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts

  20. Microlensing Signature of Binary Black Holes

    Science.gov (United States)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  1. Detection of unresolved binaries with multicolor photometry

    CERN Document Server

    Chulkov, D; Malkov, O; Sichevskij, S; Krussanova, N; Mironov, A; Zakharov, A; Kniazev, A

    2016-01-01

    The principal goal of this paper is to specify conditions of detection of unresolved binaries by multicolor photometry. We have developed a method for estimating the critical distance at which an unresolved binary of given mass and age can be detected. The method is applied to the photometric system of the planned Lyra-B spaceborne experiment. We have shown that some types of unresolved binary stars can be discovered and distinguished from single stars solely by means of photometric observations.

  2. HP3 on ExoMars - Cutting airbag cloths with the sharp tip of a mechanical mole

    Science.gov (United States)

    Krause, C.; Izzo, M.; Re, E.; Mehls, C.; Richter, L.; Coste, P.

    2009-04-01

    The HP3 - Heat Flow and Physical Properties Package - is planned to be one of the Humboldt lander-based instruments on the ESA ExoMars mission. HP3 will allow the measurement of the subsurface temperature gradient and physical as well as thermophysical properties of the subsurface regolith of Mars down to a depth of 5 meters. From these measurements, the planetary heat flux can be inferred. The HP³ instrument package consists of a mole trailing a package of thermal and electrical sensors into the regolith. Beside the payload elements Thermal Excitation and Measurement Suite and a Permittivity Probe the HP3 experiment includes sensors to detect the forward motion and the tilt of the HP3 payload compartment. The HP3 experiment will be integrated into the lander platform of the ExoMars mission. The original accommodation featured a deployment device or a robotic arm to place HP3 onto the soil outside the deflated lander airbags. To avoid adding such deployment devices, it was suggested that the HP3 mole should be capable of piercing the airbags under the lander. The ExoMars lander airbag is made of 4 Kevlar layers (2 abrasive and 2 bladders). A double fold of the airbag (a worst case) would represent a pile of 12 layers. An exploratory study has examined the possibility of piercing airbag cloths by adding sharp cutting blades on the tip of a penetrating mole. In the experimental setup representative layers were laid over a Mars soil simulant. Initial tests used a hammer-driven cutting tip and had moderate to poor results. More representative tests used a prototype of the HP3 mole and were fully successful: the default 4 layer configuration was pierced as well as the 12 layer configuration, the latter one within 3 hours and about 3000 mole strokes This improved behaviour is attributed to the use of representative test hardware where guidance and suppression of mole recoil were concerned. The presentation will provide an explanation of the technical requirements on

  3. Identification and characterization of a novel group of legume-specific, Golgi apparatus-localized WRKY and Exo70 proteins from soybean.

    Science.gov (United States)

    Chi, Yingjun; Yang, Yan; Li, Guiping; Wang, Fei; Fan, Baofang; Chen, Zhixiang

    2015-06-01

    Many plant genes belong to families that arise from extensive proliferation and diversification allowing the evolution of functionally new proteins. Here we report the characterization of a group of proteins evolved from WRKY and exocyst complex subunit Exo70 proteins through fusion with a novel transmembrane (TM) domain in soybean (Glycine max). From the soybean genome, we identified a novel WRKY-related protein (GmWRP1) that contains a WRKY domain with no binding activity for W-box sequences. GFP fusion revealed that GmWRP1 was targeted to the Golgi apparatus through its N-terminal TM domain. Similar Golgi-targeting TM domains were also identified in members of a new subfamily of Exo70J proteins involved in vesicle trafficking. The novel TM domains are structurally most similar to the endosomal cytochrome b561 from birds and close homologues of GmWRP1 and GmEx070J proteins with the novel TM domain have only been identified in legumes. Transient expression of some GmExo70J proteins or the Golgi-targeting TM domain in tobacco altered the subcellular structures labelled by a fluorescent Golgi marker. GmWRP1 transcripts were detected at high levels in roots, flowers, pods, and seeds, and the expression levels of GmWRP1 and GmExo70J genes were elevated with increased age in leaves. The legume-specific, Golgi apparatus-localized GmWRP1 and GmExo70J proteins are probably involved in Golgi-mediated vesicle trafficking of biological molecules that are uniquely important to legumes.

  4. Speech perception of noise with binary gains

    DEFF Research Database (Denmark)

    Wang, DeLiang; Kjems, Ulrik; Pedersen, Michael Syskind;

    2008-01-01

    For a given mixture of speech and noise, an ideal binary time-frequency mask is constructed by comparing speech energy and noise energy within local time-frequency units. It is observed that listeners achieve nearly perfect speech recognition from gated noise with binary gains prescribed...... by the ideal binary mask. Only 16 filter channels and a frame rate of 100 Hz are sufficient for high intelligibility. The results show that, despite a dramatic reduction of speech information, a pattern of binary gains provides an adequate basis for speech perception....

  5. Survival of planets around shrinking stellar binaries.

    Science.gov (United States)

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

  6. The structures of binary compounds

    CERN Document Server

    Hafner, J; Jensen, WB; Majewski, JA; Mathis, K; Villars, P; Vogl, P; de Boer, FR

    1990-01-01

    - Up-to-date compilation of the experimental data on the structures of binary compounds by Villars and colleagues. - Coloured structure maps which order the compounds into their respective structural domains and present for the first time the local co-ordination polyhedra for the 150 most frequently occurring structure types, pedagogically very helpful and useful in the search for new materials with a required crystal structure. - Crystal co-ordination formulas: a flexible notation for the interpretation of solid-state structures by chemist Bill Jensen. - Recent important advances in unders

  7. R144 : a very massive binary likely ejected from R136 through a binary-binary encounter

    CERN Document Server

    Oh, Seungkyung; Banerjee, Sambaran

    2013-01-01

    R144 is a recently confirmed very massive, spectroscopic binary which appears isolated from the core of the massive young star cluster R136. The dynamical ejection hypothesis as an origin for its location is claimed improbable by Sana et al. due to its binary nature and high mass. We demonstrate here by means of direct N-body calculations that a very massive binary system can be readily dynamically ejected from a R136-like cluster, through a close encounter with a very massive system. One out of four N-body cluster models produces a dynamically ejected very massive binary system with a mass comparable to R144. The system has a system mass of $\\approx$ 355 Msun and is located at 36.8 pc from the centre of its parent cluster, moving away from the cluster with a velocity of 57 km/s at 2 Myr as a result of a binary-binary interaction. This implies that R144 could have been ejected from R136 through a strong encounter with an other massive binary or single star. In addition, we discuss all massive binaries and sin...

  8. Anti-tumor Effects of Exo- and Endo-biopolymers Produced from Submerged Cultures of Three Different Mushrooms

    Science.gov (United States)

    Jeong, Yong-Tae; Yang, Byung-Keun; Li, Chun-ru

    2008-01-01

    The anti-tumor effects of exo- (EX) and endo-biopolymers (EN) produced from submerged mycelial cultures of Ganoderma applanatum (GA), Collybia confluens (CC), and Pleurotus eryngii (PE) were studied using Sarcoma 180 bearing mice. Solid tumor growth was inhibited most effectively when 40 mg/kg body weight (BW) of GA-EX or PE-EN was administered to the intraperitoneal (i.p.) cavity of BALB/c mice. The spleen and liver indexes were increased in mice following i.p. administration of GA-EX and PE-EN fractions. GA-EX and PE-EN reduced the tumor formation by 30.7% and 29.4%, respectively. GA-EX and PE-EN increased the natural killer (NK) cell activity of splenocytes by 41.3% and 28.9%, respectively. PMID:23990743

  9. Hypoglycemic Effects of Exo-biopolymers Produced by Five Different Medicinal Mushrooms in STZ-induced Diabetic Rats

    Science.gov (United States)

    Yang, Byung-Keun; Kim, Guk-Nam; Jeong, Yong-Tae; Jeong, Hun; Mehta, Pradeep

    2008-01-01

    Hypoglycemic effects of exo-biopolymers (EBP) produced by submerged mycelial cultures of Coriolus versicolor, Cordyceps sinensis, Paecilomyces japonica, Armillariella mellea, and Fomes fomentarius were investigated in streptozotocin (STZ)-induced diabetic rats. The rats from each experimental group were orally administered with EBPs (100 mg/kg BW) daily for 2 weeks. Though the hypoglycemic effect was achieved in all the cases, however, C. versicolor EBP proved as the most potent one. The administration of the C. versicolor EBP substantially reduced (29.9%) the plasma glucose level as compared to the saline administered group (control). It also reduced the plasma total cholesterol (TC), triglyceride (TG), aspartate aminotransferase (AST) and, alanine aminotransferase (ALT) levels by 9.22, 23.83, 16.93, and 27.31%, respectively. The sugar and amino acid compositions of this EBP were also analyzed in detail. PMID:23997607

  10. Impact of atmospheric refraction: How deeply can we probe exo-Earth's atmospheres during primary eclipse observations?

    CERN Document Server

    Betremieux, Y

    2013-01-01

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density, probed during primary eclipses, as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction and show that most habitable exo-Earths cannot be probed down to their surface. We present 0.4-5.0micron model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type (O5-M9) of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

  11. Modeling the Martian neutral particle radiation - predictions for ExoMars/IRAS and implications for Martian habitability during the Noachian

    Energy Technology Data Exchange (ETDEWEB)

    Ehresmann, Bent; Wimmer-Schweingruber, Robert; Burmeister, Soenke; Koehler, Jan; Kulkarni, Shri [Christian-Albrechts-Universitaet, Kiel (Germany); Reitz, Guenther [Deutsches Zentrum fuer Luft- und Raumfahrt (Germany)

    2009-07-01

    The exciting results of recent Mars exploration missions indicate that water existed on the Martian surface, which provides a possibility for life on Mars. Thus, there is an enhanced interest in analyzing the conditions for habitability on Mars, especially in the Noachian epoch. An important aspect of habitability is the radiation level of charged and neutral particles in possible habitats. Using Planetocosmics, we calculate particle radiation in the Martian atmosphere and at ground level for present-day conditions. These calculations allow us to make predictions for the measurements of the Ionizing Radiation Sensor (IRAS) on ExoMars. By changing atmosphere conditions and varying the water-content of the Martian soil, we can derive radiation levels expected during the Noachian period. We will discuss the implications of these model results in terms of Noachian habitability.

  12. Interacting Jets from Binary Protostars

    CERN Document Server

    Murphy, G C; O'Sullivan, S; Spicer, D; Bacciotti, F; Rosén, A

    2007-01-01

    We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly pa...

  13. The Young Visual Binary Database

    Science.gov (United States)

    Prato, Lisa A.; Avilez, Ian; Allen, Thomas; Zoonematkermani, Saeid; Biddle, Lauren; Muzzio, Ryan; Wittal, Matthew; Schaefer, Gail; Simon, Michal

    2017-01-01

    We have obtained adaptive optics imaging and high-resolution H-band and in some cases K-band spectra of each component in close to 100 young multiple systems in the nearby star forming regions of Taurus, Ophiuchus, TW Hya, and Orion. The binary separations for the pairs in our sample range from 30 mas to 3 arcseconds. The imaging and most of our spectra were obtained with instruments behind adaptive optics systems in order to resolve even the closest companions. We are in the process of determining fundamental stellar and circumstellar properties, such as effective temperature, Vsin(i), veiling, and radial velocity, for each component in the entire sample. The beta version of our database includes systems in the Taurus region and provides plots, downloadable ascii spectra, and values of the stellar and circumstellar properties for both stars in each system. This resource is openly available to the community at http://jumar.lowell.edu/BinaryStars/. In this poster we describe initial results from our analysis of the survey data. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

  14. Millisecond Pulsars in Close Binaries

    CERN Document Server

    Tauris, Thomas M

    2015-01-01

    In this Habilitationsschrift (Habilitation thesis) I present my research carried out over the last four years at the Argelander Institute for Astronomy (AIfA) and the Max Planck Institute for Radio Astronomy (MPIfR). The thesis summarizes my main findings and has been written to fulfill the requirements for the Habilitation qualification at the University of Bonn. Although my work is mainly focused on the topic of millisecond pulsars (MSPs), there is a fairly broad spread of research areas ranging from the formation of neutron stars (NSs) in various supernova (SN) events, to their evolution, for example, via accretion processes in binary and triple systems, and finally to their possible destruction in merger events. The thesis is organized in the following manner: A general introduction to neutron stars and millisecond pulsars is given in Chapter 1. A selection of key papers published in 2011-2014 are presented in Chapters 2-10, ordered within five main research areas (ultra-stripped SNe in close binaries, ma...

  15. Sgs1 and Exo1 suppress targeted chromosome duplication during ends-in and ends-out gene targeting.

    Science.gov (United States)

    Štafa, Anamarija; Miklenić, Marina; Zunar, Bojan; Lisnić, Berislav; Symington, Lorraine S; Svetec, Ivan-Krešimir

    2014-10-01

    Gene targeting is extremely efficient in the yeast Saccharomyces cerevisiae. It is performed by transformation with a linear, non-replicative DNA fragment carrying a selectable marker and containing ends homologous to the particular locus in a genome. However, even in S. cerevisiae, transformation can result in unwanted (aberrant) integration events, the frequency and spectra of which are quite different for ends-out and ends-in transformation assays. It has been observed that gene replacement (ends-out gene targeting) can result in illegitimate integration, integration of the transforming DNA fragment next to the target sequence and duplication of a targeted chromosome. By contrast, plasmid integration (ends-in gene targeting) is often associated with multiple targeted integration events but illegitimate integration is extremely rare and a targeted chromosome duplication has not been reported. Here we systematically investigated the influence of design of the ends-out assay on the success of targeted genetic modification. We have determined transformation efficiency, fidelity of gene targeting and spectra of all aberrant events in several ends-out gene targeting assays designed to insert, delete or replace a particular sequence in the targeted region of the yeast genome. Furthermore, we have demonstrated for the first time that targeted chromosome duplications occur even during ends-in gene targeting. Most importantly, the whole chromosome duplication is POL32 dependent pointing to break-induced replication (BIR) as the underlying mechanism. Moreover, the occurrence of duplication of the targeted chromosome was strikingly increased in the exo1Δ sgs1Δ double mutant but not in the respective single mutants demonstrating that the Exo1 and Sgs1 proteins independently suppress whole chromosome duplication during gene targeting.

  16. Measurement of dust optical depth using the solar irradiance sensor (SIS) onboard the ExoMars 2016 EDM

    Science.gov (United States)

    Toledo, D.; Arruego, I.; Apéstigue, V.; Jiménez, J. J.; Gómez, L.; Yela, M.; Rannou, P.; Pommereau, J.-P.

    2017-04-01

    The solar irradiance sensor (SIS) was included in the DREAMS package onboard the ExoMars 2016 Entry Descent and Landing Demonstrator Module, and has been selected in the METEO meteorological station onboard the ExoMars 2020 Lander. This instrument is designed to measure at different time intervals the scattered flux or the sum of direct flux and scattered flux in UVA (315-400 nm) and NIR (700-1100 nm) bands. For SIS'16, these measurements are performed by a total of 3 sensors per band placed at the faces of a truncated tetrahedron with face inclination angles of 60°. The principal goal of SIS'16 design is to perform measurements of the dust opacity in UVA and NIR wavelengths ranges, crucial parameters in the understanding of the Martian dust cycle. The retrieval procedure is based on the use of radiative transfer simulations to reproduce SIS observations acquired during daytime as a function of dust opacity. Based on different sensitivity analysis, the retrieval procedure also requires to include as free parameters (1) the dust effective radius; (2) the dust effective variance; and (3) the imaginary part of the refractive index of dust particles in UVA band. We found that the imaginary part of the refractive index of dust particles does not have a big impact on NIR signal, and hence we can kept constant this parameter in the retrieval of dust opacity at this channel. In addition to dust opacity measurements, this instrument is also capable to detect and characterize clouds by looking at the time variation of the color index (CI), defined as the ratio between the observations in NIR and UVA channels, during daytime or twilight. By simulating CI signals with a radiative transfer model, the cloud opacity and cloud altitude (only during twilight) can be retrieved. Here the different retrieval procedures that are used to analyze SIS measurements, as well as the results obtained in different sensitivity analysis, are presented and discussed.

  17. Binary Relations as a Foundation of Mathematics

    NARCIS (Netherlands)

    Kuper, J.; Barendsen, E.; Capretta, V.; Geuvers, H.; Niqui, M.

    2007-01-01

    We describe a theory for binary relations in the Zermelo-Fraenkel style. We choose for ZFCU, a variant of ZFC Set theory in which the Axiom of Foundation is replaced by an axiom allowing for non-wellfounded sets. The theory of binary relations is shown to be equi-consistent ZFCU by constructing a mo

  18. Binary Structure in David Lodge's Novels

    Institute of Scientific and Technical Information of China (English)

    高萍

    2008-01-01

    David Lodge is one of the most renowned modern English writers.He is known for the binary structure in his novels.In this paper,the writer will try to the binary structure in some of his novels to show his reflections on Catholicism and culture conflicts.

  19. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  20. Helium in atmospheres of binary stars

    Energy Technology Data Exchange (ETDEWEB)

    Leushin, V.V. (Rostovskij-na-Donu Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Fiziki)

    The helium abundances were obtained for 25 bright components of binary stars by model atmosphere analysis. The helium abundance for binary stars that lie on the main sequence are larger in the average than in single normal stars. The stars on the Hertzsppung - russel diagram lie at a larger distance from the zero age line than those with normal helium abundance.

  1. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Yungelson, Lev R.

    2006-12-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA. Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  2. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Konstantin A. Postnov

    2014-05-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  3. Bayesian analysis of exoplanet and binary orbits

    OpenAIRE

    Schulze-Hartung, Tim; Launhardt, Ralf; Henning, Thomas

    2012-01-01

    We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A.

  4. Binary Representations of Fingerprint Spectral Minutiae Features

    NARCIS (Netherlands)

    Xu, Haiyun; Veldhuis, Raymond N.J.

    2010-01-01

    A fixed-length binary representation of a fingerprint has the advantages of a fast operation and a small template storage. For many biometric template protection schemes, a binary string is also required as input. The spectral minutiae representation is a method to represent a minutiae set as a fixe

  5. The Evolution of Compact Binary Star Systems.

    Science.gov (United States)

    Postnov, Konstantin A; Yungelson, Lev R

    2014-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  6. Binary Planetary Nebulae Nuclei towards the Galactic Bulge. I. Sample Discovery, Period Distribution and Binary Fraction

    CERN Document Server

    Miszalski, B; Moffat, A F J; Parker, Q A; Udalski, A

    2009-01-01

    Binarity has been hypothesised to play an important, if not ubiquitous, role in the formation of planetary nebulae (PNe). Yet there remains a severe paucity of known binary central stars required to test the binary hypothesis and to place strong constraints on the physics of the common-envelope (CE) phase of binary stellar evolution. Large photometric surveys offer an unrivalled opportunity to efficiently discover many binary central stars. We have combined photometry from the OGLE microlensing survey with the largest sample of PNe towards the Galactic Bulge to systematically search for new binaries. A total of 21 periodic binaries were found thereby more than doubling the known sample. The orbital period distribution was found to be best described by CE population synthesis models when no correlation between primary and secondary masses is assumed for the initial mass ratio distribution. A comparison with post-CE white dwarf binaries indicates both distributions are representative of the true post-CE period ...

  7. Planet Scattering Around Binaries: Ejections, Not Collisions

    CERN Document Server

    Smullen, Rachel A; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Asid...

  8. Evolution of non-synchronized binary systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A model for binary evolution is introduced which can determine whether the rotation of components is synchronized with the orbital motion, and can calculate the evolution of both the synchronized and non-synchronized binary systems. With this model, the evolution of a binary system consisting of a 9 M⊙ star and a 6 M⊙ star is studied with mass transfer Case B. The result shows that the synchronization of the rotational and orbital periods can be reached when the binary system is a detached system and before the occurrence of the first mass transfer. After the onset of the first mass transfer, the binary system becomes non-synchronized. The mass accepted component (the secondary) rotates faster with a period much smaller than that of the orbital motion.

  9. Evolution of non-synchronized binary systems

    Institute of Scientific and Technical Information of China (English)

    黄润乾; 曾艺蓉

    2000-01-01

    A model for binary evolution is introduced which can determine whether the rotation of components is synchronized with the orbital motion, and can calculate the evolution of both the synchronized and non-synchronized binary systems. With this model, the evolution of a binary system consisting of a 9 M star and a 6 M star is studied with mass transfer Case B. The result shows that the synchronization of the rotational and orbital periods can be reached when the binary system is a detached system and before the occurrence of the first mass transfer. After the onset of the first mass transfer, the binary system becomes non-synchronized. The mass accepted component (the secondary) rotates faster with a period much smaller than that of the orbital motion.

  10. Terrestrial Planet Formation in Binary Star Systems

    Science.gov (United States)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  11. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  12. Binary Cepheids from optical interferometry

    CERN Document Server

    Gallenne, A; Mérand, A; Monnier, J D; Pietrzyński, J Breitfelder G; Gieren, W

    2013-01-01

    Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (1-40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.

  13. Record-Breaking Eclipsing Binary

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two eclipses are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two eclipses. (The blue KELT observations during the eclipse show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the eclipse last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind

  14. Stability of multiplanet systems in binaries

    Science.gov (United States)

    Marzari, F.; Gallina, G.

    2016-10-01

    Context. When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman & Wiegert (1999, AJ, 117, 621) within which planets are stable against the binary perturbations, and the Hill stability limit Δ determining the minimum separation beyond which two planets will avoid mutual close encounters. Both these parameters are derived in different contexts, i.e. Δ is usually adopted for computing the stability limit of two planets around a single star while ac is computed for a single planet in a binary system. Aims: Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. Methods: We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. Results: First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability and it does not account for planets trapped in resonance with the companion star well beyond ac. For two-planet systems, the value of Δ is close to that computed for planets around single stars, but the level of chaoticity close to it substantially increases for smaller semimajor axes and higher eccentricities of the binary orbit. In these configurations ac also begins to be unreliable and non-linear secular resonances with the stellar companion lead to chaotic behaviour well within ac, even for single planet systems. For two planet systems, the superposition of mean motion resonances, either mutual or with the binary companion, and non-linear secular resonances may lead to chaotic behaviour in all cases. We have developed a parametric semi-empirical formula determining the minimum value of the binary semimajor axis, for a given

  15. Binary dynamics near a massive black hole

    CERN Document Server

    Hopman, Clovis

    2009-01-01

    We analyze the dynamical evolution of binary stars that interact with a static background of single stars in the environment of a massive black hole (MBH). All stars are considered to be single mass, Newtonian point particles. We follow the evolution of the energy E and angular momentum J of the center of mass of the binaries with respect to the MBH, as well as their internal semi-major axis a, using a Monte Carlo method. For a system like the Galactic center, the main conclusions are the following: (1) The binary fraction can be of the order of a few percent outside 0.1 pc, but decreases quickly closer to the MBH. (2) Within ~0.1 pc, binaries can only exist on eccentric orbits with apocenters much further away from the MBH. (3) Far away from the MBH, loss-cone effects are the dominant mechanism that disrupts binaries with internal velocities close to the velocity dispersion. Closer to the MBH, three-body encounters are more effective in disrupting binaries. (4) The rate at which hard binaries become tighter ...

  16. Interrupted Binary Mass Transfer in Star Clusters

    CERN Document Server

    Leigh, Nathan W C; Toonen, Silvia

    2016-01-01

    Binary mass transfer is at the forefront of some of the most exciting puzzles of modern astrophysics, including Type Ia supernovae, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this time-scale to the mean time for stable mass transfer to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing mass transfer that are expected to be disrupted as a function of the host cluster pro...

  17. The origin of very wide binary stars

    CERN Document Server

    Kouwenhoven, M B N; Davies, Melvyn B; Parker, Richard J; Kroupa, P; Malmberg, D

    2011-01-01

    A large population of fragile, wide (> 1000 AU) binary systems exists in the Galactic field and halo. These wide binary stars cannot be primordial because of the high stellar density in star forming regions, while formation by capture in the Galactic field is highly improbable. We propose that these binary systems were formed during the dissolution phase of star clusters (see Kouwenhoven et al. 2010, for details). Stars escaping from a dissolving star cluster can have very similar velocities, which can lead to the formation of a wide binary systems. We carry out N-body simulations to test this hypothesis. The results indicate that this mechanism explains the origin of wide binary systems in the Galaxy. The resulting wide binary fraction and semi-major axis distribution depend on the initial conditions of the dissolving star cluster, while the distributions in eccentricity and mass ratio are universal. Finally, since most stars are formed in (relatively tight) primordial binaries, we predict that a large fract...

  18. ExoU contributes to late killing of Pseudomonas aeruginosa - infected endothelial cells ExoU contribui para a morte tardia de células endoteliais infectadas por Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Alessandra Mattos Saliba

    2003-11-01

    Full Text Available To ascertain the role of ExoU in late P. aeruginosa cytotoxicity, endothelial cells (EC were exposed to wild type PA103, PA103deltaexoU and PA103::exsA for 1h and to gentamicin in culture medium. After 24h, the viability of PA103-infected cells (33.7 ± 14.3% was significantly lower than the viability of PA103deltaexoU- (77.7 ± 6.3% or PA103::exsA- (79.5 ± 23.3% infected EC. P. aeruginosa cytotoxicity did not depend on the bacterial ability to interact with EC because the percentage of cells with associated PA103 (35.9 ± 15.8% was similar to the percentage in PA103deltaexoU- (34.2 ± 16.0% and lower than the percentage in PA103::exsA-infected cultures (82.9 ± 18.9%. Cell treatment with cytochalasin D reduced the PA103 internalization by EC but did not interfere with its ability to kill host cells.Para determinar o papel de ExoU na citotoxicidade tardia de P. aeruginosa, células endoteliais (CE foram expostas às cepas PA103, PA103deltaxoU e PA103::exsA por 1h e à gentamicina em meio de cultura. Após 24h, a viabilidade das CE infectadas com PA103 (33.7 ± 14.3% foi inferior à de CE infectadas com PA103deltaexoU (77.7 ± 6.3% e PA103::exsA (79.5 ± 23.3%. A citotoxicidade não dependeu da capacidade de interagir com as CE porque o percentual de células com bactérias associadas em culturas expostas a PA103 foi semelhante ao percentual em culturas expostas a PA103deltaexoU e inferior em culturas expostas a PA103::exsA. O tratamento das CE com citocalasina D reduziu a internalização de PA103, mas não interferiu em sua citotoxicidade.

  19. Interrupted Binary Mass Transfer in Star Clusters

    Science.gov (United States)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  20. Potentials of mean force for the exo and endo solvolysis of 2-norbornyl chloride in water and DMSO: A constrained molecular dynamics study

    Indian Academy of Sciences (India)

    Subodh C Tiwari; Timir Hajari; Ashish Sharma; B L Tembe

    2012-01-01

    Constrained molecular dynamics is used to calculate the potentials of mean force for the exo and endo dissociation of 2-norbornyl chlorides in two solvents, namely water and dimethyl sulphoxide (DMSO). The gas phase potential energy curves for the 2-norbornyl chlorides are computed by ab initio methods and these curves are fitted into a 12-6-1 potential for use in classical molecular dynamics simulations. The gas phase potential energy curves indicate a greater barrier for the dissociation of the endo 2-norbornyl chloride (than the exo). The potentials of mean force (PMF) in DMSO and water indicate the locations and the magnitudes of the activation barriers in these solutions and are sensitive functions of the fitted gas phase potentials.

  1. Cold dust around nearby stars (DUNES). First results: A resolved exo-Kuiper belt around the solar-like star zeta^2 Ret

    CERN Document Server

    Eiroa, C; Maldonado, J; González-García, B M; Rodmann, J; Heras, A M; Pilbratt, G L; Augereau, J -Ch; Mora, A; Montesinos, B; Ardila, D; Bryden, G; Liseau, R; Stapelfeldt, K; Launhardt, R; Solano, E; Bayo, A; Absil, O; Ar?evalo, M; Barrado, D; Beichmann, C; Danchi, W; del Burgo, C; Ertel, S; Fridlund, M; Fukagawa, M; Gutiérrez, R; Grün, E; Kamp, I; Krivov, A; Lebreton, J; Löhne, T; Lorente, R; Marshall, J; Martínez-Arnáiz, R; Meeus, G; Montes, D; Morbidelli, A; Müller, S; Mutschke, H; Nakagawa, T; Olofsson, G; Ribas, I; Roberge, A; Sanz-Forcada, J; Thébault, P; Walker, H; White, G J; Wolf, S

    2010-01-01

    We present the first far-IR observations of the solar-type stars delta Pav, HR 8501, 51 Peg and zeta^2 Ret, taken within the context of the DUNES Herschel Open Time Key Programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts around nearby solar-type stars. The observed 100 um fluxes from delta Pav, HR 8501, and 51 Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than Ldust/Lstar ~ 5 x 10^-7 (1 sigma level) around those stars. A flattened, disk-like structure with a semi-major axis of ~ 100 AU in size is detected around zeta^2 Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with Ldust/Lstar ~ 10^-5.

  2. Fast algorithms for generating binary holograms

    CERN Document Server

    Stuart, Dustin; Kuhn, Axel

    2014-01-01

    We describe three algorithms for generating binary-valued holograms. Our methods are optimised for producing large arrays of tightly focussed optical tweezers for trapping particles. Binary-valued holograms allow us to use a digital mirror device (DMD) as the display element, which is much faster than other alternatives. We describe how our binary amplitude holograms can be used to correct for phase errors caused by optical aberrations. Furthermore, we compare the speed and accuracy of the algorithms for both periodic and arbitrary arrangements of traps, which allows one to choose the ideal scheme depending on the circumstances.

  3. Discovery of a 2 Kpc Binary Quasar

    OpenAIRE

    Shields, G. A.; Junkkarinen, V.; Beaver, E. A.; Burbidge, E. M.; Cohen, R. D.; Hamann, F.; Lyons, R. W.

    2001-01-01

    LBQS 0103$-$2753 is a binary quasar with a separation of only 0.3 arcsec. The projected spacing of 2.3 kpc at the distance of the source (z = 0.848) is much smaller than that of any other known binary QSO. The binary nature is demonstrated by the very different spectra of the two components and the low probability of a chance pairing. LBQS 0103$-$2753 presumably is a galaxy merger with a small physical separation between the two supermassive black holes. Such objects may provide important con...

  4. Binary Cu-Zr Bulk Metallic Glasses

    Institute of Scientific and Technical Information of China (English)

    TANG Mei-Bo; ZHAO De-Qian; PAN Ming-Xiang; WANG Wei-Hua

    2004-01-01

    @@ We report that bulk metallic glasses (BMGs) can be produced up to 2 mm by a copper mould casting in Cux Zr1-x binary alloy with a wide glass forming composition range (45 < x < 60 at.%). We find that the formation mechanism for the binary Cu-Zr binary BMG-forming alloy is obviously different from that of the intensively studied multicomponent BMGs. Our results demonstrate that the criteria for the multicomponent alloys with composition near deep eutectic and strong liquid behaviour are no longer the major concern for designing BMGs.

  5. Dynamical mass transfer in cataclysmic binaries

    Science.gov (United States)

    Melia, Fulvio; Lamb, D. Q.

    1987-01-01

    When a binary comes into contact and mass transfer begins, orbital angular momentum is stored in the accretion disk until the disk couples tidally to the binary system. Taam and McDermott (1987) have suggested that this leads to unstable dynamical mass transfer in many cataclysmic variables in which mass transfer would otherwise be stable, and that it explains the gap between 2 and 3 h in the orbital period distribution of these systems. Here the consequences of this hypothesis for the evolution of cataclysmic binaries are explored. It is found that systems coming into contact longward of the period gap undergo one or more episodes of dynamical mass transfer.

  6. Blind iterative deconvolution of binary star images

    CERN Document Server

    Saha, S K

    1997-01-01

    The technique of Blind Iterative De-convolution (BID) was used to remove the atmospherically induced point spread function (PSF) from short exposure images of two binary stars, HR 5138 and HR 5747 obtained at the cassegrain focus of the 2.34 meter Vainu Bappu Telescope(VBT), situated at Vainu Bappu Observatory (VBO), Kavalur. The position angles and separations of the binary components were seen to be consistent with results of the auto-correlation technique, while the Fourier phases of the reconstructed images were consistent with published observations of the binary orbits.

  7. Division Unit for Binary Integer Decimals

    DEFF Research Database (Denmark)

    Lang, Tomas; Nannarelli, Alberto

    2009-01-01

    -recurrence algorithm to BID representation and implement the division unit in standard cell technology. The implementation of the proposed BID division unit is compared to that of a BCD based unit implementing the same algorithm. The comparison shows that for normalized operands the BID unit has the same latency......In this work, we present a radix-10 division unit that is based on the digit-recurrence algorithm and implements binary encodings (binary integer decimal or BID) for significands. Recent decimal division designs are all based on the binary coded decimal (BCD) encoding. We adapt the radix-10 digit...

  8. SYNTHESIS OF NOVEL CROWN ETHERS BEARING THE exo-cis-2,3-NORBORNYL GROUP AS POTENTIAL Na+ AND K+ EXTRACTANTS

    Energy Technology Data Exchange (ETDEWEB)

    Robeson, R.M.; Bonnesen, P.

    2007-01-01

    The synthesis of a series of novel dinorbornyl-16-crown-5 and dinorbornyl-18-crown-6 ethers that incorporate the exo-cis-2,3-norbornyl moiety within the macrocycle framework is described. The key starting material for the crown ethers, exo-cis-2,3-norbornanediol, was successfully prepared on a large (>30g) scale in 88% yield from norbornylene by osmium tetroxide-catalyzed hydroxylation. The syn and anti isomers of the dinorbornyl-16-crown-5 ether family were prepared using diethylene glycol with ring closure achieved using a methallyl linkage. The isomers cis-syn-cis and cis-anti-cis di-norbornano-15-methyleno-16-crown-5 (6A and 6B) could be separated using column chromatography, and a single crystal of the syn isomer 6A suitable for X-ray crystal structure analysis was obtained, thereby confi rming the syn orientation. The syn and anti isomers of the dinorbornyl-18-crown-6 ether family were successfully prepared employing a different synthetic strategy, involving the potassium–templated cyclization of two bis-hydroxyethoxy-substituted exo-cis-2,3-norbornyl groups under high dilution conditions. Attempts to fully separate cis-syn-cis di-norbornano-18-crown-6 (10A) and cis-anti-cis di-norbornano-18-crown-6 (10B) from one another using column chromatography were unsuccessful. All intermediates and products were checked for purity using either thin layer chromatography or gas chromatography, and characterized by proton and carbon NMR. Crown ethers 6AB and 10AB are to our knowledge the fi rst crown ethers to incorporate the exo-cis-2,3-norbornyl moiety into the crown ring to be successfully synthesized and characterized.

  9. Survival and growth of yeast without telomere capping by Cdc13 in the absence of Sgs1, Exo1, and Rad9.

    Directory of Open Access Journals (Sweden)

    Hien-Ping Ngo

    2010-08-01

    Full Text Available Maintenance of telomere capping is absolutely essential to the survival of eukaryotic cells. Telomere capping proteins, such as Cdc13 and POT1, are essential for the viability of budding yeast and mammalian cells, respectively. Here we identify, for the first time, three genetic modifications that allow budding yeast cells to survive without telomere capping by Cdc13. We found that simultaneous inactivation of Sgs1, Exo1, and Rad9, three DNA damage response (DDR proteins, is sufficient to allow cell division in the absence of Cdc13. Quantitative amplification of ssDNA (QAOS was used to show that the RecQ helicase Sgs1 plays an important role in the resection of uncapped telomeres, especially in the absence of checkpoint protein Rad9. Strikingly, simultaneous deletion of SGS1 and the nuclease EXO1, further reduces resection at uncapped telomeres and together with deletion of RAD9 permits cell survival without CDC13. Pulsed-field gel electrophoresis studies show that cdc13-1 rad9Delta sgs1Delta exo1Delta strains can maintain linear chromosomes despite the absence of telomere capping by Cdc13. However, with continued passage, the telomeres of such strains eventually become short and are maintained by recombination-based mechanisms. Remarkably, cdc13Delta rad9Delta sgs1Delta exo1Delta strains, lacking any Cdc13 gene product, are viable and can grow indefinitely. Our work has uncovered a critical role for RecQ helicases in limiting the division of cells with uncapped telomeres, and this may provide one explanation for increased tumorigenesis in human diseases associated with mutations of RecQ helicases. Our results reveal the plasticity of the telomere cap and indicate that the essential role of telomere capping is to counteract specific aspects of the DDR.

  10. Aram Dorsum, Candidate ExoMars Rover Landing Site: a Noachian Inverted Fluvial Channel System in Arabia Terra Mars

    Science.gov (United States)

    Balme, Matthew; Grindrod, Peter; Sefton-Nash, Elliot; Davis, Joel; Gupta, Sanjeev; Fawdon, Peter

    2016-04-01

    Much of Mars' Noachian-aged southern highlands is dissected by systems of fluvial channels and valleys > 3.7 Ga in age. Arabia Terra, lying between the southern highlands and the northern lowlands, is similarly ancient, yet apparently has few valley networks. This regional lack of valley networks only matches Noachian precipitation predictions from climate models if the Noachian climate was dry and cold [1]. In this scenario, highlands dissection was caused by transient flows of meltwater from large, regionally restricted ice-bodies. However, new results [2,3] show that Arabia Terra is not as poorly dissected as previously thought, and in fact there are extensive networks of inverted channel systems. Here, we describe an example of such a system - Aram Dorsum - which has been studied extensively as an ExoMars Rover candidate landing site. Aram Dorsum is an ~100 km long, 1-2 km wide, branching, flat-topped ridge system, in western Arabia Terra. We have mapped the system using CTX images, DEMs and other data. We interpret the ridge system to be fluvial in origin, preserved in positive relief due to infill and differential erosion; this working hypothesis is used as a conceptual framework for the study. Aram Dorsum is a branching, multi-level, contributory network, set in surrounding floodplains-like material. This demonstrates that it was a relatively long-lived, aggradational fluvial system, rather than an erosional outflow or bedrock-carved fluvial channel. Interestingly, the system shows little evidence for unconfined lateral channel migration, so there must have been significant bank stability. Aram Dorsum was therefore probably once a sizable river and, as just one example of many similar systems, is an exemplar for the middle part of a regional sediment transport system that could have extended from the southern highlands to the northern lowlands. Like Aram Dorsum, many of these other recently-recognized fluvial systems have an origin more consistent with

  11. Busting Up Binaries: Encounters Between Compact Binaries and a Supermassive Black Hole

    CERN Document Server

    Addison, Eric; Larson, Shane

    2015-01-01

    Given the stellar density near the galactic center, close encounters between compact object binaries and the supermassive black hole are a plausible occurrence. We present results from a numerical study of close to 13 million such encounters. Consistent with previous studies, we corroborate that, for binary systems tidally disrupted by the black hole, the component of the binary remaining bound to the hole has eccentricity ~ 0.97 and circularizes dramatically by the time it enters the classical LISA band. Our results also show that the population of surviving binaries merits attention. These binary systems experience perturbations to their internal orbital parameters with potentially interesting observational consequences. We investigated the regions of parameter space for survival and estimated the distribution of orbital parameters post-encounter. We found that surviving binaries harden and their eccentricity increases, thus accelerating their merger due gravitational radiation emission and increasing the p...

  12. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  13. Overexpression of OsRecQl4 and/or OsExo1 enhances DSB-induced homologous recombination in rice.

    Science.gov (United States)

    Kwon, Yong-Ik; Abe, Kiyomi; Osakabe, Keishi; Endo, Masaki; Nishizawa-Yokoi, Ayako; Saika, Hiroaki; Shimada, Hiroaki; Toki, Seiichi

    2012-12-01

    During homologous recombination (HR)-mediated DNA double-strand break (DSB) repair in eukaryotes, an initial step is the creation of a 3'-single-stranded DNA (ssDNA) overhang via resection of a 5' end. Rad51 polymerizes on this ssDNA to search for a homologous sequence, and the gapped sequence is then repaired using an undamaged homologous DNA strand as template. Recent studies in eukaryotes indicate that resection of the DSB site is promoted by the cooperative action of RecQ helicase family proteins: Bloom helicase (BLM) in mammals or Sgs1 in yeast, and exonuclease 1 (Exo1). However, the role of RecQ helicase and exonuclease during the 5'-resection process of HR in plant cells has not yet been defined. Here, we demonstrate that overexpression of rice proteins OsRecQl4 (BLM counterpart) and/or OsExo1 (Exo1 homolog) can enhance DSB processing, as evaluated by recombination substrate reporter lines in rice. These results could be applied to construct an efficient gene targeting system in rice.

  14. Binary neutron star merger simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bruegmann, Bernd [Jena Univ. (Germany)

    2016-11-01

    Our research focuses on the numerical tools necessary to solve Einstein's equations. In recent years we have been particularly interested in spacetimes consisting of two neutron stars in the final stages of their evolution. Because of the emission of gravitational radiation, the objects are driven together to merge; the emitted gravitational wave signal is visualized. This emitted gravitational radiation carries energy and momentum away from the system and contains information about the system. Late last year the Laser Interferometer Gravitational-wave Observatory (LIGO) began searches for these gravitational wave signals at a sensitivity at which detections are expected. Although such systems can radiate a significant amount of their total mass-energy in gravitational waves, the gravitational wave signals one expects to receive on Earth are not strong, since sources of gravitational waves are often many millions of light years away. Therefore one needs accurate templates for the radiation one expects from such systems in order to be able to extract them out of the detector's noise. Although analytical models exist for compact binary systems when the constituents are well separated, we need numerical simulation to investigate the last orbits before merger to obtain accurate templates and validate analytical approximations. Due to the strong nonlinearity of the equations and the large separation of length scales, these simulations are computationally demanding and need to be run on large supercomputers. When matter is present the computational cost as compared to pure black hole (vacuum) simulations increases even more due to the additional matter fields. But also more interesting astrophysical phenomena can happen. In fact, there is the possibility for a strong electromagnetic signal from the merger (e.g., a short gamma-ray burst or lower-energy electromagnetic signatures from the ejecta) and significant neutrino emission. Additionally, we can expect that

  15. Searching for amino-acid homochirality on Mars with the Mars Organic Molecule Analyzer (MOMA) onboard ExoMars

    Science.gov (United States)

    Buch, A.; Freissinet, C.; Sternberg, R.; Brault, A.; Szopa, C.; Claude-Geffroy, C.; Coll, P. J.; Grand, N.; Raulin, F.; Pinick, V.; Goesmann, F.

    2012-12-01

    The joint ESA-Roscosmos Exo-Mars-2018 rover mission plans to seek the signs of a past or a present life on Mars. The Mars Organic Molecule Analyzer (MOMA) experiment onboard theExoMars rover will be a key analytical tool in providing molecular information from Mars solid samples, with a specific focus on the characterization of their organic content. In this purpose, one of MOMA's main instruments is a gas chromatograph-mass spectrometer (GC-MS), which provides a unique ability to characterize a broad range of compounds and allow chemical analyses on volatile and refractory species. The challenge with the analysis of this refractory matter embedded in soil is their primary extraction before their analysis by GC-MS. Since the extraction of organic matter is not possible by liquid solvent extraction, we have developed a method based on the thermodesorption and subsequent derivatization of the organic molecules. The goal of the thermodesorption is to extract the organic matter by heating the sample quickly enough not to degrade its organic content. One of the main focuses is to determine the chirality of this organic matter, notably amino acids. Indeed, on Earth, homochirality of molecules is an indicator for the presence of life. Amino acids appear to bear only the left-handed form (L) in living system. However, other refractory compounds can raise interest: nucleobases, carboxylic acids and PAHs are among molecules supported by life as we know it, and all of them can display chirality. The intrinsic chirality of molecules being thermosensitive, the thermodesorption parameters have been adjusted to occur within a range of temperatures from 150 °C to 300 °C over a period of 30 s to 10 min, depending on the chemical compound. Under these conditions, we have shown that amino acids are not degraded and that their chirality is preserved. Once extracted, refractory molecules with labile hydrogens (e.g. amino acids, nucleobases, carboxylic acids, etc.) are derivatized

  16. Surgery versus Active Monitoring in Intermittent Exotropia (SamExo: study protocol for a pilot randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Buck Deborah

    2012-10-01

    Full Text Available Abstract Background Childhood intermittent exotropia [X(T] is a type of strabismus (squint in which one eye deviates outward at times, usually when the child is tired. It may progress to a permanent squint, loss of stereovision and/or amblyopia (reduced vision. Treatment options for X(T include eye patches, glasses, surgery and active monitoring. There is no consensus regarding how this condition should be managed, and even when surgery is the preferred option clinicians disagree as to the optimal timing. Reports on the natural history of X(T are limited, and there is no randomised controlled trial (RCT evidence on the effectiveness or efficiency of surgery compared with active monitoring. The SamExo (Surgery versus Active Monitoring in Intermittent Exotropia pilot study has been designed to test the feasibility of such a trial in the UK. Methods Design: an external pilot patient randomised controlled trial. Setting: four UK secondary ophthalmology care facilities at Newcastle NHS Hospitals Foundation Trust, Sunderland Eye Infirmary, Moorfields Eye Hospital and York NHS Trust. Participants: children aged between 6 months and 16 years referred with suspected and subsequently diagnosed X(T. Recruitment target is a total of 144 children over a 9-month period, with 120 retained by 9-month outcome visit. Randomisation: permuted blocks stratified by collaborating centre, age and severity of X(T. Interventions: initial clinical assessment; randomisation (eye muscle surgery or active monitoring; 3-, 6- and 9-month (primary outcome clinical assessments; participant/proxy completed questionnaire covering time and travel costs, health services use and quality of life (Intermittent Exotropia Questionnaire; qualitative interviews with parents to establish reasons for agreeing or declining participation in the pilot trial. Outcomes: recruitment and retention rates; nature and extent of participation bias; nature and extent of biases arising from crossover or

  17. New Insights into X-ray Binaries

    CERN Document Server

    Casares, Jorge

    2009-01-01

    X-ray binaries are excellent laboratories to study collapsed objects. On the one hand, transient X-ray binaries contain the best examples of stellar-mass black holes while persistent X-ray binaries mostly harbour accreting neutron stars. The determination of stellar masses in persistent X-ray binaries is usually hampered by the overwhelming luminosity of the X-ray heated accretion disc. However, the discovery of high-excitation emission lines from the irradiated companion star has opened new routes in the study of compact objects. This paper presents novel techniques which exploits these irradiated lines and summarises the dynamical masses obtained for the two populations of collapsed stars: neutron stars and black holes.

  18. A mesoscopic model for binary fluids

    CERN Document Server

    Echeverria, C; Alvarez-Llamoza, O; Orozco-Guillén, E E; Morales, M; Cosenza, M G

    2016-01-01

    We propose a model to study symmetric binary fluids, based in the mesoscopic molecular simulation technique known as multiparticle collision, where space and state variables are continuous while time is discrete. We include a repulsion rule to simulate segregation processes that does not require the calculation of the interaction forces between particles, thus allowing the description of binary fluids at a mesoscopic scale. The model is conceptually simple, computationally efficient, maintains Galilean invariance, and conserves the mass and the energy in the system at micro and macro scales; while momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as density profile, width of the interface, phase separation and phase growth. We also apply the model to study binary fluids in crowded environments with consistent results.

  19. Red-giant stars in eccentric binaries

    Directory of Open Access Journals (Sweden)

    Beck P. G.

    2015-01-01

    Full Text Available The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs.

  20. Binary Biometric Representation through Pairwise Polar Quantization

    NARCIS (Netherlands)

    Chen, Chun; Veldhuis, Raymond; Tistarelli, M.; Nixon, M.

    2009-01-01

    Binary biometric representations have great significance for data compression and template protection. In this paper, we introduce pairwise polar quantization. Furthermore, aiming to optimize the discrimination between the genuine Hamming distance (GHD) and the imposter Hamming distance (IHD), we pr

  1. Searching for Pulsars in Close Binary Systems

    CERN Document Server

    Jouteux, S; Stappers, B W; Jonker, P; Van der Klis, M

    2001-01-01

    We present a detailed mathematical analysis of the Fourier response of binary pulsar signals whose frequencies are modulated by circular orbital motion. The fluctuation power spectrum of such signals is found to be \

  2. Tidal capture formation of Low Mass X-Ray Binaries from wide binaries in the field

    CERN Document Server

    Michaely, Erez

    2015-01-01

    We present a potentially efficient dynamical formation scenario for Low Mass X-ray Binaries (LMXBs) in the field, focusing on black-hole (BH) LMXBs. In this formation channel LMXBs are formed from wide binaries $(>1000$ AU) with a BH component and a stellar companion. The wide binary is perturbed by fly-by's of field stars and its orbit random-walks and changes over time. This diffusion process can drive the binary into a sufficiently eccentric orbit such that the binary components tidally interact at peri-center and the binary evolves to become a short period binary, which eventually evolves into an LMXB. The formation rate of LMXBs through this channel mostly depends on the number of such BH wide binaries progenitors, which in turn depends on the velocity kicks imparted to BHs (or NSs) at birth. We consider several models for the formation and survival of such wide binaries, and calculate the LMXB formation rates for each model. We find that models where BHs form through direct collapse with no/little natal...

  3. Evolution of Binary Stars in Multiple-Population Globular Clusters - II. Compact Binaries

    CERN Document Server

    Hong, Jongsuk; Sollima, Antonio; McMillan, Stephen L W; D'Antona, Franca; D'Ercole, Annibale

    2016-01-01

    We present the results of a survey of N-body simulations aimed at exploring the evolution of compact binaries in multiple-population globular clusters.We show that as a consequence of the initial differences in the structural properties of the first-generation (FG) and the second-generation (SG) populations and the effects of dynamical processes on binary stars, the SG binary fraction decreases more rapidly than that of the FG population. The difference between the FG and SG binary fraction is qualitatively similar to but quantitatively smaller than that found for wider binaries in our previous investigations.The evolution of the radial variation of the binary fraction is driven by the interplay between binary segregation, ionization and ejection. Ionization and ejection counteract in part the effects of mass segregation but for compact binaries the effects of segregation dominate and the inner binary fraction increases during the cluster evolution. We explore the variation of the difference between the FG an...

  4. Dixie Valley Bottoming Binary Unit

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Dale [Terra-Gen Sierra Holdings, LLC, Reno, NV (United States)

    2014-12-21

    This binary plant is the first air cooled, high-output refrigeration based waste heat recovery cycle in the industry. Its working fluid is environmentally friendly and as such, the permits that would be required with a hydrocarbon based cycle are not necessary. The unit is largely modularized, meaning that the unit’s individual skids were assembled in another location and were shipped via truck to the plant site. The Air Cooled Condensers (ACC), equipment piping, and Balance of Plant (BOP) piping were constructed at site. This project further demonstrates the technical feasibility of using low temperature brine for geothermal power utilization. The development of the unit led to the realization of low temperature, high output, and environmentally friendly heat recovery systems through domestic research and engineering. The project generates additional renewable energy, resulting in cleaner air and reduced carbon dioxide emissions. Royalty and tax payments to governmental agencies will increase, resulting in reduced financial pressure on local entities. The major components of the unit were sourced from American companies, resulting in increased economic activity throughout the country.

  5. Binary module test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, J.R.; Colley, T.C.; Pundyk, J.

    1980-12-01

    The objective of this project was to design and test a binary loop module representative of and scaleable to commercial size units. The design was based on state-of-the-art heat exchanger technology, and the purpose of the tests was to confirm performance of a supercritical boiling cycle using isobutane and a mixture of isobutane and isopentane as the secondary working fluid. The module was designed as one percent of a 50 MW unit. It was installed at Magma Power's East Mesa geothermal field and tested over a period of approximately 4 months. Most of the test runs were with isobutane but some data were collected for hydrocarbon mixtures. The results of the field tests are reported. In general these results indicate reasonably good heat balances and agreement with overall heat transfer coefficients calculated by current stream analysis methods and available fluid property data; however, measured pressure drops across the heat exchangers were 20 percent higher than estimated. System operation was stable under all conditions tested.

  6. Near-Optimal Compressive Binary Search

    OpenAIRE

    Malloy, Matthew L.; Nowak, Robert D.

    2012-01-01

    We propose a simple modification to the recently proposed compressive binary search. The modification removes an unnecessary and suboptimal factor of log log n from the SNR requirement, making the procedure optimal (up to a small constant). Simulations show that the new procedure performs significantly better in practice as well. We also contrast this problem with the more well known problem of noisy binary search.

  7. Statistical pattern classification with binary variables.

    Science.gov (United States)

    Young, T Y; Liu, P S; Rondon, R J

    1981-02-01

    Binary random variables are regarded as random vectors in a binary-field (modulo-2) linear vector space. A characteristic function is defined and related results derived using this formulation. Minimax estimation of probability distributions using an entropy criterion is investigated, which leads to an A-distribution and bilinear discriminant functions. Nonparametric classification approaches using Hamming distances and their asymptotic properties are discussed. Experimental results are presented.

  8. Binary compact object inspiral: Detection expectations

    Indian Academy of Sciences (India)

    Vassiliki Kalogera

    2004-10-01

    We review the current estimates of binary compact object inspiral rates in particular in view of the recently discovered highly relativistic binary pulsar J0737-3039. One of the robust results is that, because of this discovery, the rate estimates for binary neutron stars have increased by a factor of 6-7 independent of any uncertainties related to the pulsar population properties. This rate increase has dramatic implications for gravitational wave detectors. For initial LIGO, the most probable detection rates for double neutron star (DNS) inspirals is 1 event/(5{250) yr; at 95% confidence we obtain rates up to 1/1.5 yr. For advanced LIGO, the most probable rates are 20-1000 events/yr. These predictions, for the first time, bring the expectations for DNS detections by initial LIGO to the astrophysically relevant regime. We also use our models to predict that the large-scale Parkes multibeam pulsar survey with acceleration searches could detect an average of three to four binary pulsars similar to those known at present. In comparison, rate estimates for binaries with black holes are derived based on binary evolution calculation, and based on the optimistic ends of the ranges, remain an important candidate for inspiral detection in the next few years. We also consider another aspect of the detectability of binary inspiral: the effect of precession on the detection efficiency of astrophysically relevant binaries. Based on our current astrophysical expectations, large tilt angles are not favored. As a result the decrease in detection rate varies rather slowly with black hole spin magnitude and is within 20-30% of the maximum possible values.

  9. The DEBCat detached eclipsing binary catalogue

    OpenAIRE

    2014-01-01

    Detached eclipsing binary star systems are our primary source of measured physical properties of normal stars. I introduce DEBCat: a catalogue of detached eclipsing binaries with mass and radius measurements to the 2% precision necessary to put useful constraints on theoretical models of stellar evolution. The catalogue was begun in 2006, as an update of the compilation by Andersen (1991). It now contains over 170 systems, and new results are added on appearance in the refereed literature. DE...

  10. An improved catalog of halo wide binary candidates

    CERN Document Server

    Allen, Christine

    2014-01-01

    We present an improved catalog of halo wide binaries, compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. (2004), and Chanam\\'e \\& Gould. (2004) but we have also included binaries from the lists of Ryan (1992) and Zapatero-Osorio \\& Martin (2004). All binaries were carefully checked and their distances and systemic radial velocities are included, when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries we ended up with 211 probable halo binaries, for 150 of which radial velocities are available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law $f...

  11. Studying Low Mass X-Ray Binaries: Revealing the Optical Counterpart in 1747-214 and Measuring the Masses of the Black Holes in 1859+226 and 1009-45

    Science.gov (United States)

    Gelino, Dawn M.; Tomsick, John A.

    2003-02-01

    Low mass x-ray binaries (LMXBs) contain compact, black hole (BH) or neutron star (NS) primaries, and cool, low-mass secondary stars. A limited number of BHs and NSs have accurate mass measurements. It is important to determine the primary mass of the LMXBs to better understand how BH masses influence their outburst behavior, and to better constrain the NS equations of state. To determine the mass of the primary object we need to measure the orbital inclination, i. We propose to determine i for two BH LMXBs, XTE J1859+226 and GRS 1009-45 (=N Vel 93) through modeling of their ellipsoidal variations. Because most LMXBs are not eclipsing, modeling their light curves is currently the only feasible method for determining the inclination. We will model the light curves with WD98. We also propose to identify the optical counterpart to the NS system EXO 1747-214, in order to begin the process of measuring the NS mass. We have successfully used NOAO facilities and this modeling technique to find accurate BH masses in four LMXBs. In order to expand the sample of known BH and NS systems, we request seven nights on the KPNO and CTIO 4m to obtain optical and infrared data on XTE J1859+226, GRS 1009-45, and EXO 1747-214.

  12. Texture classification by texton: statistical versus binary.

    Directory of Open Access Journals (Sweden)

    Zhenhua Guo

    Full Text Available Using statistical textons for texture classification has shown great success recently. The maximal response 8 (Statistical_MR8, image patch (Statistical_Joint and locally invariant fractal (Statistical_Fractal are typical statistical texton algorithms and state-of-the-art texture classification methods. However, there are two limitations when using these methods. First, it needs a training stage to build a texton library, thus the recognition accuracy will be highly depended on the training samples; second, during feature extraction, local feature is assigned to a texton by searching for the nearest texton in the whole library, which is time consuming when the library size is big and the dimension of feature is high. To address the above two issues, in this paper, three binary texton counterpart methods were proposed, Binary_MR8, Binary_Joint, and Binary_Fractal. These methods do not require any training step but encode local feature into binary representation directly. The experimental results on the CUReT, UIUC and KTH-TIPS databases show that binary texton could get sound results with fast feature extraction, especially when the image size is not big and the quality of image is not poor.

  13. Spectroscopic subsystems in nearby wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5-m telescope to study short-period systems. Data reduction is described, mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, for some of them orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67pc. It is found that 43 binaries contain at least one subsystem and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods match the simple prescription proposed by the author (2014, AJ, 147, 87). The remaining 53 simple wide binaries with a median projected separation of 1300AU have the distri...

  14. Coronal activity from the ASAS eclipsing binaries

    CERN Document Server

    Szczygiel, D M; Paczynski, B; Pojmanski, G; Pilecki, B

    2008-01-01

    We combine the catalogue of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalogue, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L_X/L_bol ~ a few x 10^-4, similar to the ratio of soft X-ray to bolometric flux F_X/F_bol in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs -- stars with significant outer convection zones -- a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called "super-saturation" phenomena. Our work shows that wide-...

  15. Impact of atmospheric refraction: how deeply can we probe exo-earth's atmospheres during primary eclipse observations?

    Energy Technology Data Exchange (ETDEWEB)

    Bétrémieux, Yan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Kaltenegger, Lisa, E-mail: betremieux@mpia.de [Also at Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. (United States)

    2014-08-10

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density and pressure, probed during primary eclipses as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction for all exoplanets and tabulate the critical altitude, density, and pressure for an exoplanet identical to Earth with a 1 bar N{sub 2}/O{sub 2} atmosphere as a function of both the incident stellar flux (Venus, Earth, and Mars-like) at the top of the atmosphere and the spectral type (O5-M9) of the host star. We show that such a habitable exo-Earth can be probed to a surface pressure of 1 bar only around the coolest stars. We present 0.4-5.0 μm model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

  16. Antiproliferative and Apoptosis-inducing Effect of exo-Protoporphyrin IX based Sonodynamic Therapy on Human Oral Squamous Cell Carcinoma

    Science.gov (United States)

    Lv, Yanhong; Zheng, Jinhua; Zhou, Qi; Jia, Limin; Wang, Chunying; Liu, Nian; Zhao, Hong; Ji, Hang; Li, Baoxin; Cao, Wenwu

    2017-01-01

    Sonodynamic therapy (SDT) is an innovative modality for cancer treatment. But the biological effect of SDT on oral squamous cell carcinoma has not been studied. Our previous study has shown that endo-Protoporphyrin IX based SDT (ALA-SDT) could induce apoptosis in human tongue squamous carcinoma SAS cells through mitochondrial pathway. Herein, we investigated the effect of exo- Protoporphyrin based SDT (PpIX-SDT) on SAS cells in vitro and in vivo. We demonstrated that PpIX-SDT increased the ratio of cells in the G2/M phase and induced 3–4 times more cell apoptosis compared to sonocation alone. PpIX-SDT caused cell membrane damage prior to mitochondria damage and upregulated the expression of Fas and Fas L, while the effect was suppressed if cells were pre-treated with p53 inhibitor. Additionally, we examined the SDT-induced cell apoptosis in two cell lines with different p53 status. The increases of p53 expression and apoptosis rate in wild-type p53 SAS cells were found in the SDT group, while p53-mutated HSC-3 cells did not show such increase. Our data suggest that PpIX-SDT suppress the proliferation of SAS cells via arresting cell cycle at G2/M phase and activating the extrinsic Fas-mediated membrane receptor pathway to induce apoptosis, which is regulated by p53. PMID:28102324

  17. VizieR Online Data Catalog: ExoMol XVIII. VO high-temperature spectrum (McKemmish+, 2016)

    Science.gov (United States)

    McKemmish, L. K.; Yurchenko, S. N.; Tennyson, J.

    2016-07-01

    The files comprising this line list are in the standard ExoMol format, and are labelled XXV-YYO_VOMYT.states and .trans, where XX and YY are the mass numbers of the vanadium and oxygen isotopes respectively. The isotopologues covered including their nuclear spin degeneracy factors gns are: (51V)(16O) gns=8. The partition function from 1 to 8000K in 1K intervals are also provided in files named 51V-16O_VOMYT.pf and consist of two columns (T/K followed by Q). The data for each isotopologue are in two parts. The first, 51V-16OVOMYT.states contains a list of rovibronic states. Each state is labelled with the total angular momentum, state degeneracy, total (+/-) and e/f parities, vibrational quantum number, projection of the electronic, spin and total angular momenta. Each state has a unique number, which is the number of the row in which it appears in the file. This number is the means by which the state is related to the second part of the data system, the transitions files. The transition files 51V-16OVOMYT*.trans contain four columns: the reference number in the energy file of the upper state; that of the lower state; the Einstein A coefficient of the transition; the transition wavenumber. (3 data files).

  18. Evaluation of the effect of indigenous mycogenic silver nanoparticles on soil exo-enzymes in barite mine contaminated soils

    Science.gov (United States)

    Gaddam, Durga Prameela; Devamma, Nagalakshmi; Prasad, Tollamadugu Naga Venkata Krishna Vara

    2015-04-01

    The biosynthesis of nanoparticles has received increasing attention due to the growing need to develop safe, cost-effective and environmentally friendly technologies for nanoscale materials synthesis. In this report, silver nanoparticles (AgNPs) were synthesized by treating aqueous Ag+ ions with the culture supernatants of indigenous fungal species of Fusarium solani isolated from barite mine contaminated soils. The formation of AgNPs might be an enzyme-mediated extracellular reaction process. The localized surface plasmon resonance of the formed AgNPs was recorded using UV-VIS spectrophotometer and was characterized using the techniques transmission electron microscopy, particle size analyzer, Fourier transform-infrared spectroscopy (FT-IR), particle size (dynamic light scattering) and zeta potential. The synthesized AgNPs were stable, polydispersed with the average size of 80 nm. FT-IR spectra reveals that proteins and carboxylic groups present in the fungal secrets might be responsible for the reduction and stabilization of the silver ions. Applied to the barite mine contaminated soils, concentration of AgNPs and incubation period significantly influences the soil exo-enzymatic activities, viz., urease, phosphatase, dehydrogenase and β-glucosidase. To the best of our knowledge, this is the first report on this kind of work in barite mine contaminated soils.

  19. Clouds in the Forecast? A Joint Spitzer and HST Investigation of Clouds and Hazes for Two Exo-Neptunes

    Science.gov (United States)

    Kreidberg, Laura; Morley, Caroline; Line, Michael; Stevenson, Kevin; Dragomir, Diana

    2016-08-01

    Recent observations of transiting planets have revealed that clouds and hazes are common in exoplanet atmospheres. Little is known, however, about how the clouds/hazes form, what their composition is, and how their properties vary with planet parameters. We propose to characterize the atmospheres of two exo-Neptunes, GJ 436b and GJ 3470b, both of which show evidence for clouds or hazes in their near-infrared spectra. We will measure precise 3.6 and 4.5 micron transit depths for these planets, to compare with existing high-precision data at shorter wavelengths. We will also obtain a UV spectrum for GJ 3470 with HST/COS to enable accurate models of the planet's photochemistry. These observations will enable us to distinguish at high confidence between a range of physically realistic models for the atmospheric chemistry, including methanogenic photochemical hazes and equilibrium salt/sulfide clouds. The measurements will enable comparative planetology with the handful of other small, cool worlds currently accessible to observation, and serve as a first assessment of the prevalence, origin, and composition of clouds and haze in metal-enriched atmospheres below 1000 K. Our findings will guide the design of future observations of increasingly Earth-like worlds with JWST.

  20. Azide anions inhibit GH-18 endochitinase and GH-20 Exo β-N-acetylglucosaminidase from the marine bacterium Vibrio harveyi.

    Science.gov (United States)

    Sirimontree, Paknisa; Fukamizo, Tamo; Suginta, Wipa

    2016-02-01

    Vibrio harveyi is a bioluminescent marine bacterium that utilizes chitin as its sole source of energy. In the course of chitin degradation, the bacterium primarily secretes an endochitinase A (VhChiA) to hydrolyze chitin, generating chitooligosaccharide fragments that are readily transported into the cell and broken down to GlcNAc monomers by an exo β-N-acetylglucosaminidase (VhGlcNAcase). Here we report that sodium salts, especially sodium azide, inhibit two classes of these chitin-degrading enzymes (VhChiA and VhGlcNAcase) with distinct modes of action. Kinetic analysis of the enzymatic hydrolysis of pNP-glycoside substrates reveals that sodium azide inhibition of VhChiA has a mixed-type mode, but that it inhibits VhGlcNAcase competitively. We propose that azide anions inhibit chitinase activity by acting as strong nucleophiles that attack Cγ of the catalytic Glu or Cβ of the neighbouring Asp residues. Azide anions may bind not only to the catalytic centre, but also to the other subsites in the substrate-binding cleft of VhChiA. In contrast, azide anions may merely occupy the small-binding pocket of VhGlcNAcase, thereby blocking the accessibility of its active site by short-chain substrates.

  1. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS-mediated cardiomyocyte hypertrophy.

    Science.gov (United States)

    Tigchelaar, Wardit; Yu, Hongjuan; de Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Silljé, Herman H W

    2015-01-15

    Recently, a locus at the mitochondrial exo/endonuclease EXOG gene, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrophy in cardiomyocytes. Depletion of EXOG in primary neonatal rat ventricular cardiomyocytes (NRVCs) induced a marked increase in cardiomyocyte hypertrophy. Depletion of EXOG, however, did not result in loss of mitochondrial DNA integrity. Although EXOG depletion did not induce fetal gene expression and common hypertrophy pathways were not activated, a clear increase in ribosomal S6 phosphorylation was observed, which readily explains increased protein synthesis. With the use of a Seahorse flux analyzer, it was shown that the mitochondrial oxidative consumption rate (OCR) was increased 2.4-fold in EXOG-depleted NRVCs. Moreover, ATP-linked OCR was 5.2-fold higher. This increase was not explained by mitochondrial biogenesis or alterations in mitochondrial membrane potential. Western blotting confirmed normal levels of the oxidative phosphorylation (OXPHOS) complexes. The increased OCR was accompanied by a 5.4-fold increase in mitochondrial ROS levels. These increased ROS levels could be normalized with specific mitochondrial ROS scavengers (MitoTEMPO, mnSOD). Remarkably, scavenging of excess ROS strongly attenuated the hypertrophic response. In conclusion, loss of EXOG affects normal mitochondrial function resulting in increased mitochondrial respiration, excess ROS production, and cardiomyocyte hypertrophy.

  2. A Novel and Conserved Plasmodium Sporozoite Membrane Protein SPELD is Required for Maturation of Exo-erythrocytic Forms

    Science.gov (United States)

    Al-Nihmi, Faisal Mohammed Abdul; Kolli, Surendra Kumar; Reddy, Segireddy Rameswara; Mastan, Babu S.; Togiri, Jyothi; Maruthi, Mulaka; Gupta, Roshni; Sijwali, Puran Singh; Mishra, Satish; Kumar, Kota Arun

    2017-01-01

    Plasmodium sporozoites are the infective forms of malaria parasite to vertebrate host and undergo dramatic changes in their transcriptional repertoire during maturation in mosquito salivary glands. We report here the role of a novel and conserved Plasmodium berghei protein encoded by PBANKA_091090 in maturation of Exo-erythrocytic Forms (EEFs) and designate it as Sporozoite surface Protein Essential for Liver stage Development (PbSPELD). PBANKA_091090 was previously annotated as PB402615.00.0 and its transcript was recovered at maximal frequency in the Serial Analysis of the Gene Expression (SAGE) of Plasmodium berghei salivary gland sporozoites. An orthologue of this transcript was independently identified in Plasmodium vivax sporozoite microarrays and was designated as Sporozoite Conserved Orthologous Transcript-2 (scot-2). Functional characterization through reverse genetics revealed that PbSPELD is essential for Plasmodium liver stage maturation. mCherry transgenic of PbSPELD localized the protein to plasma membrane of sporozoites and early EEFs. Global microarray analysis of pbspeld ko revealed EEF attenuation being associated with down regulation of genes central to general transcription, cell cycle, proteosome and cadherin signaling. pbspeld mutant EEFs induced pre-erythrocytic immunity with 50% protective efficacy. Our studies have implications for attenuating the human Plasmodium liver stages by targeting SPELD locus. PMID:28067322

  3. Measurements of the ion fraction and mobility of alpha and beta decay products in liquid xenon using EXO-200

    CERN Document Server

    Albert, J B; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; O'Sullivan, K; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Robinson, A; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wright, J D; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2015-01-01

    Alpha decays in the EXO-200 detector are used to measure the fraction of charged $^{218}\\mathrm{Po}$ and $^{214}\\mathrm{Bi}$ daughters created from alpha and beta decays, respectively. $^{222}\\mathrm{Rn}$ alpha decays in liquid xenon (LXe) are found to produce $^{218}\\mathrm{Po}^{+}$ ions $50.3 \\pm 3.0\\%$ of the time, while the remainder of the $^{218}\\mathrm{Po}$ atoms are neutral. The fraction of $^{214}\\mathrm{Bi}^{+}$ from $^{214}\\mathrm{Pb}$ beta decays in LXe is found to be $76.4 \\pm 5.7\\%$, inferred from the relative rates of $^{218}\\mathrm{Po}$ and $^{214}\\mathrm{Po}$ alpha decays in the LXe. The average velocity of $^{218}\\mathrm{Po}$ ions is observed to decrease for longer drift times. Initially the ions have a mobility of $0.390 \\pm 0.006~\\mathrm{cm}^2/(\\mathrm{kV}~\\mathrm{s})$, and at long drift times the mobility is $0.219 \\pm 0.004~\\mathrm{cm}^2/(\\mathrm{kV}~\\mathrm{s})$. Time constants associated with the change in mobility during drift of the $^{218}\\mathrm{Po}^{+}$ ions are found to be propor...

  4. Selective dissolution in binary alloys

    Science.gov (United States)

    McCall, Carol Rene

    Corrosion is an important issue in the design of engineering alloys. De-alloying is an aspect of alloy corrosion related to the selective dissolution of one or more of the components in an alloy. The work reported herein focuses on the topic of de-alloying specific to single-phase binary noble metal alloy systems. The alloy systems investigated were gold-silver and gold-copper. The onset of a bulk selective dissolution process is typically marked by a critical potential whereby the more reactive component in the alloy begins dissolving from the bulk, leading to the formation of a bi-continuous solid-void morphology. The critical potential was investigated for the entire composition range of gold-silver alloys. The results presented herein include the formulation of an expression for critical potential as a function of both alloy and electrolyte composition. Results of the first investigation of underpotential deposition (UPD) on alloys are also presented herein. These results were implemented as an analytical tool to provide quantitative measurements of the surface evolution of gold during de-alloying. The region below the critical potential was investigated in terms of the compositional evolution of the alloy surface. Below the critical potential, there is a competition between the dissolution of the more reactive alloying constituent (either silver or copper) and surface diffusion of gold that serves to cover dissolution sites and prevent bulk dissolution. By holding the potential at a prescribed value below the critical potential, a time-dependent gold enrichment occurs on the alloy surface leading to passivation. A theoretical model was developed to predict the surface enrichment of gold based on the assumption of layer-by-layer dissolution of the more reactive alloy constituent. The UPD measurements were used to measure the time-dependent surface gold concentration and the results agreed with the predictions of the theoretical model.

  5. Exploring the Birth of Binary Stars

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    More than half of all stars are thought to be in binary or multiple star systems. But how do these systems form? The misaligned spins of some binary protostars might provide a clue.Two Formation ModelsIts hard to tell how multiple-star systems form, since these systems are difficult to observe in their early stages. But based on numerical simulations, there are two proposed models for the formation of stellar binaries:Turbulent fragmentationTurbulence within a single core leads to multiple dense clumps. These clumps independently collapse to form stars that orbit each other.Disk fragmentationGravitational instabilities in a massive accretion disk cause the formation of a smaller, secondary disk within the first, resulting in two stars that orbit each other.Log column density for one of the authors simulated binary systems, just after the formation of two protostars. Diamonds indicate the protostar positions. [Adapted from Offner et al. 2016]Outflows as CluesHow can we differentiate between these formation mechanisms? Led by Stella Offner (University of Massachusetts), a team of scientists has suggested that the key isto examine the alignment of the stars protostellar outflows jets that are often emitted from the poles of young, newly forming stars.Naively, wed expect that disk fragmentation would produce binary stars with common angular momentum. As the stars spins would be aligned, they would therefore also launch protostellar jets that were aligned with each other. Turbulent fragmentation, on the other hand, would cause the stars to have independent angular momentum. This would lead to randomly oriented spins, so the protostellar jets would be misaligned.Snapshots from the authors simulations. Left panel of each pair: column density; green arrows giveprotostellar spin directions. Right panel: synthetic observations produced from the simulations; cyan arrows giveprotostellar outflow directions. [Offner et al. 2016]Simulations of FragmentationIn order to better

  6. Absolute dimensions of eclipsing binaries XXVIII. BK pegasi and other F-type binaries

    DEFF Research Database (Denmark)

    Clausen, Jens Viggo; Frandsen, S.; Bruntt, H.

    2010-01-01

     stars: evolution / stars: fundamental parameters / binaries: eclipsing / stars: individual: BK¿Peg / stars: individual: BW¿Aqr / techniques: spectroscopic Udgivelsesdato: June 24...... stars: evolution / stars: fundamental parameters / binaries: eclipsing / stars: individual: BK¿Peg / stars: individual: BW¿Aqr / techniques: spectroscopic Udgivelsesdato: June 24...

  7. New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems

    CERN Document Server

    Bluhm, P; Vanzi, L; Soto, M G; Vos, J; Wittenmyer, R A; Olivares, F; Drass, H; Mennickent, R E; Vuckovic, M; Rojo, P; Melo, C H F

    2016-01-01

    We report the discovery of 24 spectroscopic binary companions to giant stars. We fully constrain the orbital solution for 6 of these systems. We cannot unambiguously derive the orbital elements for the remaining stars because the phase coverage is incomplete. Of these stars, 6 present radial velocity trends that are compatible with long-period brown dwarf companions.The orbital solutions of the 24 binary systems indicate that these giant binary systems have a wide range in orbital periods, eccentricities, and companion masses. For the binaries with restricted orbital solutions, we find a range of orbital periods of between $\\sim$ 97-1600 days and eccentricities of between $\\sim$ 0.1-0.4. In addition, we studied the metallicity distribution of single and binary giant stars. We computed the metallicity of a total of 395 evolved stars, 59 of wich are in binary systems. We find a flat distribution for these binary stars and therefore conclude that stellar binary systems, and potentially brown dwarfs, have a diffe...

  8. On the reconstruction of binary and permutation matrices under (binary) tomographic constraints

    NARCIS (Netherlands)

    Brunetti, S.; Del Lungo, A.; Gritzmann, P.; de Vries, S.

    2008-01-01

    The paper studies the problem of reconstructing binary matrices constrained by binary tomographic information. We prove new NP-hardness results that sharpen previous complexity results in the realm of discrete tomography but also allow applications to related problems for permutation matrices. Hence

  9. Towards the field binary population: Influence of orbital decay on close binaries

    CERN Document Server

    Korntreff, Christina; Pfalzner, Susanne

    2012-01-01

    Surveys of the binary populations in the solar neighbourhood have shown that the periods of G- and M-type stars are log-normally distributed. However, observations of young binary populations suggest a log-uniform distribution. Clearly some process(es) change the period distribution over time. Most stars form in star clusters, in which two important dynamical processes occur: i) gas-induced orbital decay of embedded binary systems and ii) destruction of soft binaries in three-body interactions. The emphasis here is on orbital decay which has been largely neglected so far. Using a combination of Monte-Carlo and dynamical nbody modelling it is demonstrated here that the cluster dynamics destroys the number of wide binaries, but leaves short-period binaries basically undisturbed even for a initially log-uniform distribution. By contrast orbital decay significantly reduces the number and changes the properties of short-period binaries, but leaves wide binaries largely uneffected. Until now it was unclear whether ...

  10. Birth of Massive Black Hole Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Colpi, M.; /Milan Bicocca U.; Dotti, M.; /Insubria U., Como; Mayer, L.; /Zurich, ETH; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  11. Massive gaseous discs around SMBH binaries: Binary decay and tidal disruptions

    Directory of Open Access Journals (Sweden)

    Brem P.

    2012-12-01

    Full Text Available We investigate the evolution of black hole binaries embedded within geometrically thin gas discs. Our results imply that such discs can produce black hole mergers for relatively low-mass binaries, and that a significant population of eccentric binaries might exist at separations of a few 0.01 pc. These binaries may be detectable due to the time-variable accretion on to the black holes. If the disc fragments, then the newly-born stars will continue driving the binary to its coalescence, although at a slower rate. Interestingly, our preliminary analysis shows that these stars will be disrupted at a rate of ∼10−4–2 · 10−5 events per year per system.

  12. Nonconservative Mass Transfer in Massive Binaries and the Formation of Wolf-Rayet+O Binaries

    CERN Document Server

    Shao, Yong

    2016-01-01

    The mass transfer efficiency during the evolution of massive binaries is still uncertain. We model the mass transfer processes in a grid of binaries to investigate the formation of Wolf-Rayet+O (WR+O) binaries, taking into account two kinds of non-conservative mass transfer models: Model I with rotation-dependent mass accretion and Model II of half mass accretion. Generally the mass transfer in Model I is more inefficient, with the average efficiency in a range of $\\sim0.2-0.7$ and $ \\lesssim0.2 $ for Case A and Case B mass transfer, respectively. We present the parameter distributions for the descendant WR+O binaries. By comparing the modeled stellar mass distribution with the observed Galactic WR+O binaries, we find that highly non-conservative mass transfer is required.

  13. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  14. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  15. Beyond binaries : a way forward for comparativeeducation

    Directory of Open Access Journals (Sweden)

    Marianne Larsen

    2012-09-01

    Full Text Available Binary discourses shape and produce the stories we construct about the field of comparative education. In the first part of this article, I review a set of binary discourses that have characterized social science research since the Enlightenment, including: quantitative-qualitative, nomotheticidiographic, inductive-deductive, and practice-theory. We can think of each of these binaries at opposite ends of a set of spectrums. In the second section of the paper, I show some of the ways in which these binaries have influenced the ways that we write and talk about research within the field of comparative education. I refer to the notion of binary discourses and the productive capacity of these discourses to shape our field. I then outline some critiques of these binaries to demonstrate the inherent limitations of binary discourses, and why we need to move beyond binaries in our research, and in the histories about our field. Finally, I present some tentative conclusions on ways to get ourselves out of the trap of binary thinking.Los discursos binarios moldean y producen los argumentos que construimos sobre la disciplina de la Educación Comparada. En la primera parte de este artículo, analizo un conjunto de discursos binarios que han caracterizado la investigación en Ciencias Sociales desde la Ilustración, incluyendo la cuantitativa-cualitativa, nomotética-idiográfica, inductivadeductiva, y la práctica-teoría. Podemos pensar sobre cada uno de estos discursos binarios como argumentos en los polos de un conjunto de posibilidades. En la segunda sección del artículo, revelo algunos modos en los que estos discursos binarios han influenciado las formas a través de las cuales escribimos y analizamos la investigación en el ámbito de la Educación Comparada. Analizo la noción de discursos binarios y la capacidad productiva de estos discursos de impactar nuestra ciencia. Seguidamente expongo algunas críticas de estos discursos binarios con el

  16. Planet scattering around binaries: ejections, not collisions

    Science.gov (United States)

    Smullen, Rachel A.; Kratter, Kaitlin M.; Shannon, Andrew

    2016-09-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary star and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically affects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Systems similar to the only observed multiplanet circumbinary system, Kepler-47, can arise from much more tightly packed, unstable systems. Only extreme initial conditions introduce differences in the final planet populations. Thus, we suggest that any intrinsic differences in the populations are imprinted by formation.

  17. The binary white dwarf LHS 3236

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L. [US Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Dupuy, Trent J.; Liu, Michael C. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hartkopf, William I. [US Naval Observatory, 3450 Massachusetts Avenue, N.W., Washington, DC 20392-5420 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, New South Wales, NSW 2109 (Australia); Leggett, S. K., E-mail: hch@nofs.navy.mil [Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States)

    2013-12-10

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s{sup –1}, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M {sub ☉}; also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M {sub ☉}. In either case, the cooling ages of the stars are ∼3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M {sub ☉}) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.

  18. A Model for Contact Binary Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A model for contact binary systems is presented, which incorporates the following special features: a) The energy exchange between the components is based on the understanding that the energy exchange is due to the release of potential, kinetic and thermal energies of the exchanged mass. b) A special form of mass and angular momentum loss occurring in contact binaries is losses via the outer Lagrangian point. c) The effects of spin, orbital rotation and tidal action on the stellar structure as well as the effect of meridian circulation on the mixing of the chemical elements are considered. d) The model is valid not only for low-mass contact binaries but also for high-mass contact binaries. For illustration, we used the model to trace the evolution of a massive binary system consisting of one 12M⊙ and one 5M⊙ star. The result shows that the start and end of the contact stage fall within the semi-detached phase during which the primary continually transfers mass to the secondary. The time span of the contact stage is short and the mass transfer rate is very large. Therefore, the contact stage can be regarded as a special part of the semi-detached phase with a large mass transfer rate. Both mass loss through the outer Lagrangian point and oscillation between contact and semi-contact states can occur during the contact phase, and the effective temperatures of the primary and the secondary are almost equal.

  19. Stability of multiplanet systems in binaries

    CERN Document Server

    Marzari, F

    2016-01-01

    When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman and Wiegert (1999) within which planets are stable against the binary perturbations, and the Hill stability limit Delta determining the minimum separation beyond which two planets will avoid mutual close encounters. Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability. For two planet systems, the value of Delta is close to that computed for planets around single stars, but the level of chaoti...

  20. Orbital eccentricities in primordial black holes binaries

    CERN Document Server

    Cholis, Ilias; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on timescales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO a...

  1. Orbital eccentricities in primordial black hole binaries

    Science.gov (United States)

    Cholis, Ilias; Kovetz, Ely D.; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B.; Raccanelli, Alvise

    2016-10-01

    It was recently suggested that the merger of ˜30 M⊙ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on time scales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO and the Einstein Telescope to such effects. We show that if PBHs make up the dark matter, then roughly one event should have a detectable eccentricity given LIGO's expected sensitivity and observing time of six years. The Einstein Telescope should see O (10 ) such events after ten years.

  2. An interferometric view of binary stars

    CERN Document Server

    Boffin, Henri M J

    2016-01-01

    The study of binary stars is critical to apprehend many of the most interesting classes of stars. Moreover, quite often, the study of stars in binary systems is our only mean to constrain stellar properties, such as masses and radii. Unfortunately, a great fraction of the most interesting binaries are so compact that they can only be apprehended by high-resolution techniques, mostly by interferometry. I present some results highlighting the use of interferometry in the study of binary stars, from finding companions and deriving orbits, determining the mass and radius of stars, to studying mass transfer in symbiotic stars, and tackling luminous blue variables. In particular, I show how interferometric studies using the PIONIER instrument have allowed us to confirm a dichotomy within symbiotic stars, obtain masses of stars with a precision better than 1%, and help us find a new Eta Carinae-like system. I will also illustrate the benefits for the study of binary stars one would get from upgrading the VLT Interfe...

  3. Stacking Analysis of Binary Systems with HAWC

    Science.gov (United States)

    Brisbois, Chad; HAWC Collaboration

    2017-01-01

    Detecting binary systems at TeV energies is an important problem because only a handful of such systems are currently known. The nature of such systems is typically thought to be composed of a compact object and a massive star. The TeV emission from these systems does not obviously correspond to emission in GeV or X-ray, where many binary systems have previously been found. This study focuses on a stacking method to detect TeV emission from LS 5039, a known TeV binary, to test its efficacy in HAWC data. Stacking is a widely employed method for increasing signal to noise ratio in optical astronomy, but has never been attempted previously with HAWC. HAWC is an ideal instrument to search for TeV binaries, because of its wide field of view and high uptime. Applying this method to the entire sky may allow HAWC to detect binary sources of very short or very long periods not sensitive to current analyses. NSF, DOE, Los Alamos, Michigan Tech, CONACyt, UNAM, BUAP.

  4. The Galactic Distribution of Contact Eclipsing Binaries

    Science.gov (United States)

    Castelaz, Michael W.; Dorn, Leah; Breitfeld, Abby; Mies, Regan; Avery, Tess

    2017-01-01

    The number of eclipsing contact binaries in different galactic latitudes and longitudes show peak distributions in the number per square degree in two latitudinal zones (-30 degrees to -25 degrees and +25 degrees to +30 degrees) and large fluctuations in longitude (Huang and Wade 1966, ApJ, 143, 146). Semi-detached or detached binaries are largely concentrated in the galactic plane as shown by Paczynski et al. (MNRAS, 368, 1311), different from the distribution of contact eclipsing binaries. The differences in distributions of different types of eclipsing binaries may be related to either distances or interstellar reddening. We will present a method to calculate photometric distances of W Urase Majoris systems (W UMa; used as a proxy for contact binaries) from 2MASS J and K magnitudes and interstellar reddening models (Schlafly and Finkbeiner 2011, ApJ. 737, 103). We compare the distances to those calculated from the period-luminosity-color relationship described by Rucinski (2004, NewAR, 48, 703). The W UMa systems are taken from the General Catalog of Variable Stars.

  5. Urey Prize Lecture: Binary Minor Planets

    Science.gov (United States)

    Margot, J. L.

    2004-11-01

    The discovery of binary systems in the near-Earth, main belt, and Kuiper belt populations provides an abundance of new data that expand our knowledge of the physics and chemistry of the solar system. Binary minor planets form as a result of collisional, tidal, and capture processes that are important to study as they play major roles in the formation and evolution of planetary systems. The frequency of occurrence of such processes directly reflects the dynamical environment in the various populations. Observations of binaries provide a powerful way to measure the bulk properties of small bodies, which in turn lead to inferences about their composition and internal structure. These data may offer a rare glimpse of what physical and chemical conditions prevailed when protoplanets formed, and what subsequent evolution took place. In the case of the Kuiper Belt, the study of a handful of binaries forces us to rethink how dense and how bright these bodies are, and to significantly revise our current mass estimates for the entire population. The number of known binary minor planets has increased dramatically over the past few years, with roughly ten new discoveries each year. I will attempt to summarize recent developments, with examples drawn from my observations with the Hubble, Palomar, Keck, Arecibo and Goldstone telescopes.

  6. Debris disks in main sequence binary systems

    CERN Document Server

    Trilling, D E; Stapelfeldt, K R; Rieke, G H; Su, K Y L; Gray, R O; Corbally, C J; Bryden, G; Chen, C H; Boden, A; Beichman, C A

    2006-01-01

    We observed 69 A3-F8 main sequence binary star systems using the Multiband Imaging Photometer for Spitzer onboard the Spitzer Space Telescope. We find emission significantly in excess of predicted photospheric flux levels for 9(+4/-3)% and 40(+7/-6)% of these systems at 24 and 70 microns, respectively. Twenty two systems total have excess emission, including four systems that show excess emission at both wavelengths. A very large fraction (nearly 60%) of observed binary systems with small (<3 AU) separations have excess thermal mission. We interpret the observed infrared excesses as thermal emission from dust produced by collisions in planetesimal belts. The incidence of debris disks around main sequence A3-F8 binaries is marginally higher than that for single old AFGK stars. Whatever combination of nature (birth conditions of binary systems) and nurture (interactions between the two stars) drives the evolution of debris disks in binary systems, it is clear that planetesimal formation is not inhibited to a...

  7. Development and validation of a high performance liquid chromatographic method for the separation of exo and endo isomers of granatamine (9-methyl-9-azabicyclo[3.3.1]nonan-3-amine); a key intermediate of granisetron.

    Science.gov (United States)

    Krishna, S Radha; Babu, P Suresh; Rao, B M; Rao, N Someswara

    2009-12-01

    A simple and accurate high-performance liquid chromatographic method was developed for the determination of exo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine in endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine, commercially known as grantamine and used as a key intermediate in the preparation of granisetron bulk drug. Chromatographic separation of the exo and endo isomers of 9-methyl-9-azabicyclo[3.3.1]nonan-3-amine was achieved on an Inertsil C8 column using a mobile phase containing 0.3% trifluoroacetic acid. The resolution between the two isomers was found to be more than 4. The limit of detection (LOD) and limit of quantification (LOQ) of exo isomer were 0.8 and 2.5 microg x mL(-1) respectively, for a 10 microL injection volume. The percentage recovery of exo-isomer ranged from 99 to 102% w/w in the endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine sample. The test solution and mobile phase were observed to be stable up to 48 h after preparation. The validated method yielded good results for precision, linearity, accuracy, robustness and ruggedness. The proposed method was found to be suitable and accurate for the quantitative determination of exo-isomer in bulk samples of endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine.

  8. RecJ, ExoI and RecG are required for genome maintenance but not for generation of genetic diversity by repeat-mediated phase variation in Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Gaurav A.; Woodhall, Mark R.; Hood, Derek W.; Moxon, E. Richard [Molecular Infectious Diseases Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS (United Kingdom); Bayliss, Christopher D. [Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)], E-mail: cdb12@le.ac.uk

    2008-04-02

    High levels of genetic diversity are generated in Haemophilus influenzae populations through DNA repeat-mediated phase variation and recombination with DNA fragments acquired by uptake from the external milieu. Conversely, multiple pathways for maintenance of the genome sequence are encoded in H. influenzae genomes. In Escherichia coli, mutations in single-stranded-DNA exonucleases destabilise tandem DNA repeats whilst inactivation of recG can stabilise repeat tracts. These enzymes also have varying effects on recombination. Deletion mutations were constructed in H. influenzae genes encoding homologs of ExoI, RecJ and RecG whilst ExoVII was refractory to mutation. Inactivation of RecJ and RecG, but not ExoI, increased sensitivity to irradiation with ultraviolet light. An increase in spontaneous mutation rate was not observed in single mutants but only when both RecJ and ExoI were mutated. None of the single- or double-mutations increased or decreased the rates of slippage in tetranucleotide repeat tracts. Furthermore, the exonuclease mutants did not exhibit significant defects in horizontal gene transfer. We conclude that RecJ, ExoI and RecG are required for maintenance of the H. influenzae genome but none of these enzymes influence the generation of genetic diversity through mutations in the tetranucleotide repeat tracts of this species.

  9. Mineralogic Context of the Circum-Chryse Planitia Candidate Landing Sites for the ExoMars Rover Mission

    Science.gov (United States)

    Carter, John; Loizeau, Damien; Quantin, Cathy; Balme, Matt; Poulet, Francois; Gupta, Sanjeev; Vago, Jorge; Bibring, Jean-Pierre

    2015-04-01

    The ExoMars rover mission [1] will sample ancient, aqueously altered terrains to search for traces of extinct life and characterize the water history of Early Mars. These objectives translate into site-specific constraints in order to maximize the opportunity to access morphological and/or chemical markers for past aqueous environments and possibly life [2]. Currently, four candidate landing sites are being considered, all located on the margin of Chryse Planitia and all exhibiting hydrous clays within or near the ellipse. Assessing the composition and morphologic/stratigraphic context of these clays is necessary to narrow down possible formation scenarios and help rank the sites according to their relevance to the science goals. This work investigates the aqueous mineralogy of the circum-Chyrse region -where the LS are proposed-, in order to provide a framework for future in-depth investigations. Regional mapping of the clay mineralogy was performed using the OMEGA and CRISM NIR imaging spectrometers [3,4]. Global coverage of the circum-Chryse margin was achieved with OMEGA while detailed mapping was carried out locally with OMEGA and CRISM. Over 250 observations with pixel scales ranging 20 m - 4 km were investigated. Additionally, detailed analysis of the clay chemical composition was carried out using linear unmixing which provided the relative abundances of several Fe/Mg-rich phyllosilicate endmembers in the region. The analysis revealed large exposures of dominantly Fe/Mg-rich phyllosilicates over most of the preserved Noachian-aged margins of Chryse Planitia. These minerals have spectral features which are generally similar to what is found elsewhere on Mars [5], consistent with either vermiculites or smectite-bearing mixed-layered clays [6,7]. A regional outlier exists at and around the Mawrth Vallis LS: the most common clay there is likely Fe-rich nontronite associated with Al-rich phyllosilicates within layered deposits [8,9], indicating a different

  10. Stereological assessment of extracellular polymeric substances, exo-enzymes, and specific bacterial strains in bioaggregates using fluorescence experiments.

    Science.gov (United States)

    Adav, Sunil S; Lin, Justin Chun-Te; Yang, Zhen; Whiteley, Chris G; Lee, Duu-Jong; Peng, Xiao-Feng; Zhang, Zhen-Peng

    2010-01-01

    This review addresses the introduction of fluorescent molecular tags into exo-enzymes and extra polymeric substances of bioaggregates and the use of confocal laser scanning microscopy (CLSM) to map their role, purpose and quantitative description of the biological processes they undertake. Multiple color staining coupled with CLSM and fluorescent in situ hybridisation (FISH) and flow cytometry have identified the individual polymeric substances, whether they are proteins, lipids, polysaccharides, nucleic acids or antibodies, as well as the microorganisms in the bioaggregate. Procedures are presented for simultaneous multicolor staining with seven different fluorochromes - SYTOX Blue for nucleic acids; Nile red for lipids; Calcofluor white [CW] for beta-polysaccharides; concanavalin A [Con A] for alpha-poly-saccharides; fluorescein-isothiocyanate [FITC] for proteins; SYTO 63 for live microbial cells and Calcium Green for monitoring calcium levels in the microbial cells. For the distribution of certain microbial strains, metabolic enzymes and extrapolymeric substances to be quantitatively described the generated colored images are converted into digital forms under specific predefined criteria. Procedures and computer software programs (Amira; MATLAB) are presented in order to quantitatively establish grid patterns from the CLSM images. The image is digitized using a threshholding algorithm followed by a reconstruction of the image as a volumetric grid for finite element simulation. The original color image is first converted to a grey followed by resizing, detection and modification of bilevel images and finally a total reversal of the image colors. The grid file is then used by specific computer software (Gambit, Fluent) for further numerical studies incorporating chemical reactions, transport processes and computational fluid dynamics including intra-bioaggregate fluid flow, and heat and mass transfer within the bioaggregate matrix.

  11. Actin and dynamin recruitment and the lack thereof at exo- and endocytotic sites in PC12 cells.

    Science.gov (United States)

    Felmy, Felix

    2009-06-01

    Protein recruitment during endocytosis is well characterized in fibroblasts. Since fibroblasts do not engage in regulated exocytosis, only information about protein recruitment during constitutive endocytosis is provided. Furthermore, the cortical actin of fibroblasts is characterized by stress fibers rather than a thick cortical meshwork. A cell model, which differs in these features, could provide insight into the heterogeneity of protein recruitment to constitutive and exocytosis coupled endocytotic areas. Therefore, this study investigates the sequence of protein recruitment in PC12 cells, a well documented exocytotic cell model with thick actin cortex. Using real time total-internal-reflection fluorescence microscopy it was found that at the plasma membrane steady, but not transient, dynamin-1-EGFP or -mCherry fluorescence spots that rapidly dimmed coincided with markers for constitutive endocytotic such as clathrin-LC-dsRed and transferrin-receptor-pHluorin. Clathrin-LC-dsRed and dynamin-1-EGFP were further used to determine the temporal sequence of protein recruitment to areas of constitutive endocytosis. mCherry- and EGFP-beta-actin, Arp-3-EGFP and EGFP-mAbp1 were slowly recruited before the dynamin-1-mCherry fluorescence dimmed, but their fluorescence peaked after the loss of clathrin-LC-dsRed commenced. Furthermore, mCherry-beta-actin fluorescence increased before exocytosis, indicating redistribution prior to release. Also, no average dynamin-1-mCherry recruitment was observed within 50 s to regions of exocytosis marked by NPY-mGFP. This indicates that the temporal-spatial coupling between regulated exo-and endocytosis is rather limited in PC12 cells. Furthermore, the time course of the protein recruitment to constitutive endocytotic sites might depend on the subcellular morphology such as the size of the actin cortex.

  12. Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

    2014-10-15

    We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

  13. Molecular characterization of a Penicillium chrysogenum exo-rhamnogalacturonan lyase that is structurally distinct from other polysaccharide lyase family proteins.

    Science.gov (United States)

    Iwai, Marin; Kawakami, Takuya; Ikemoto, Takeshi; Fujiwara, Daisuke; Takenaka, Shigeo; Nakazawa, Masami; Ueda, Mitsuhiro; Sakamoto, Tatsuji

    2015-10-01

    We previously described an endo-acting rhamnogalacturonan (RG) lyase, termed PcRGL4A, of Penicillium chrysogenum 31B. Here, we describe a second RG lyase, called PcRGLX. We determined the cDNA sequence of the Pcrglx gene, which encodes PcRGLX. Based on analyses using a BLAST search and a conserved domain search, PcRGLX was found to be structurally distinct from known RG lyases and might belong to a new polysaccharide lyase family together with uncharacterized fungal proteins of Nectria haematococca, Aspergillus oryzae, and Fusarium oxysporum. The Pcrglx cDNA gene product (rPcRGLX) expressed in Escherichia coli demonstrated specific activity against RG but not against homogalacturonan. Divalent cations were not essential for the enzymatic activity of rPcRGLX. rPcRGLX mainly released unsaturated galacturonosyl rhamnose (ΔGR) from RG backbones used as the substrate from the initial stage of the reaction, indicating that the enzyme can be classified as an exo-acting RG lyase (EC 4.2.2.24). This is the first report of an RG lyase with this mode of action in Eukaryota. rPcRGLX acted synergistically with PcRGL4A to degrade soybean RG and released ΔGR. This ΔGR was partially decorated with galactose (Gal) residues, indicating that rPcRGLX preferred oligomeric RGs to polymeric RGs, that the enzyme did not require Gal decoration of RG backbones for degradation, and that the enzyme bypassed the Gal side chains of RG backbones. These characteristics of rPcRGLX might be useful in the determination of complex structures of pectins.

  14. Síntese e atividade fitotóxica de 2-fenil-6,7-exo-isopropilidenodioxi-8-oxabiciclo [3.2.1]oct-2-eno Synthesis and phytotoxic activity of 2-Phenyl-6,7-exo isopropylidenedioxi-8-oxabicyclo[3.2.1]oct-2-ene

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio A. Barbosa

    2000-08-01

    Full Text Available The [3+4] cycloaddition between furan and the oxyallyl cation generated from 1-bromo-1-phenylpropan-2-one (4, resulted in the formation of 2-phenyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (5 in 30% yield. This compound was further converted into 2-phenyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]oct-2-ene (13 in 35.4% yield. The selective effect of compound (13 and its isomer 3-phenyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]oct -2-ene (1a on the radicle growth of Sorghum bicolor L. (sorghum and Cucumis sativus L. (cucumber were evaluated. For both plants, compound 13 showed to be more potent than its isomer 1a.

  15. Rapid Compact Binary Coalescence Parameter Estimation

    Science.gov (United States)

    Pankow, Chris; Brady, Patrick; O'Shaughnessy, Richard; Ochsner, Evan; Qi, Hong

    2016-03-01

    The first observation run with second generation gravitational-wave observatories will conclude at the beginning of 2016. Given their unprecedented and growing sensitivity, the benefit of prompt and accurate estimation of the orientation and physical parameters of binary coalescences is obvious in its coupling to electromagnetic astrophysics and observations. Popular Bayesian schemes to measure properties of compact object binaries use Markovian sampling to compute the posterior. While very successful, in some cases, convergence is delayed until well after the electromagnetic fluence has subsided thus diminishing the potential science return. With this in mind, we have developed a scheme which is also Bayesian and simply parallelizable across all available computing resources, drastically decreasing convergence time to a few tens of minutes. In this talk, I will emphasize the complementary use of results from low latency gravitational-wave searches to improve computational efficiency and demonstrate the capabilities of our parameter estimation framework with a simulated set of binary compact object coalescences.

  16. Binary Code Disassembly for Reverse Engineering

    Directory of Open Access Journals (Sweden)

    Marius Popa

    2013-01-01

    Full Text Available The disassembly of binary file is used to restore the software application code in a readable and understandable format for humans. Further, the assembly code file can be used in reverse engineering processes to establish the logical flows of the computer program or its vulnerabilities in real-world running environment. The paper highlights the features of the binary executable files under the x86 architecture and portable format, presents issues of disassembly process of a machine code file and intermediate code, disassembly algorithms which can be applied to a correct and complete reconstruction of the source file written in assembly language, and techniques and tools used in binary code disassembly.

  17. Gravitational waves from spinning eccentric binaries

    CERN Document Server

    Csizmadia, Péter; Rácz, István; Vasúth, Mátyás

    2012-01-01

    This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity. In addition, by investigating the validity of the energy balance relat...

  18. Memory effect from spinning unbound binaries

    CERN Document Server

    De Vittori, Lorenzo; Gupta, Anuradha; Jetzer, Philippe

    2014-01-01

    We present a recently developed prescription to obtain ready-to-use gravitational wave (GW) polarization states for spinning compact binaries on hyperbolic orbits. We include leading order spin-orbit interactions, invoking 1.5PN-accurate quasi-Keplerian parametrization for the radial part of the orbital dynamics. We also include radiation reaction effects on $h_+$ and $h_{\\times}$ during the interaction. In the GW signals from spinning binaries there is evidence of the memory effect in both polarizations, in contrast to the non-spinning case, where only the cross polarizations exhibits non-vanishing amplitudes at infinite time. We also compute 1PN-accurate GW polarization states for non-spinning compact binaries in unbound orbits in a fully parametric way, and compare them with existing waveforms.

  19. Hybrid Black-Hole Binary Initial Data

    Science.gov (United States)

    Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-01-01

    "Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

  20. Hybrid black-hole binary initial data

    CERN Document Server

    Mundim, Bruno C; Zlochower, Yosef; Nakano, Hiroyuki; Campanelli, Manuela

    2010-01-01

    Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class.Quant.Grav.27:114005,2010], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculation was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.

  1. Hybrid black-hole binary initial data

    Energy Technology Data Exchange (ETDEWEB)

    Mundim, Bruno C; Zlochower, Yosef; Nakano, Hiroyuki; Campanelli, Manuela [Center for Computational Relativity and Gravitation, School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623 (United States); Kelly, Bernard J, E-mail: bcmsma@astro.rit.edu, E-mail: bernard.j.kelly@nasa.gov, E-mail: yosef@astro.rit.edu, E-mail: nakano@astro.rit.edu, E-mail: manuela@astro.rit.edu [CRESST and Gravitational Astrophysics Laboratory, NASA/GSFC, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2011-07-07

    Traditional black-hole (BH) binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al (2010, Class. Quantum Grav. 27 114005), a new binary BH initial data with radiation content derived from post-Newtonian (PN) theory was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless 'wavy' metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesirable features: unphysical horizon mass loss and large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.

  2. The Expressive Power of Binary Submodular Functions

    CERN Document Server

    Zivny, Stanislav; Jeavons, Peter G

    2008-01-01

    It has previously been an open problem whether all Boolean submodular functions can be decomposed into a sum of binary submodular functions over a possibly larger set of variables. This problem has been considered within several different contexts in computer science, including computer vision, artificial intelligence, and pseudo-Boolean optimisation. Using a connection between the expressive power of valued constraints and certain algebraic properties of functions, we answer this question negatively. Our results have several corollaries. First, we characterise precisely which submodular functions of arity 4 can be expressed by binary submodular functions. Next, we identify a novel class of submodular functions of arbitrary arities which can be expressed by binary submodular functions, and therefore minimised efficiently using a so-called expressibility reduction to the Min-Cut problem. More importantly, our results imply limitations on this kind of reduction and establish for the first time that it cannot be...

  3. Asteroseismic modelling of the Binary HD 176465

    CERN Document Server

    Nsamba, B; Campante, T L; Reese, D R; White, T R; Hernández, A García; Jiang, C

    2016-01-01

    The detection and analysis of oscillations in binary star systems is critical in understanding stellar structure and evolution. This is partly because such systems have the same initial chemical composition and age. Solar-like oscillations have been detected by Kepler in both components of the asteroseismic binary HD 176465. We present an independent modelling of each star in this binary system. Stellar models generated using MESA (Modules for Experiments in Stellar Astrophysics) were fitted to both the observed individual frequencies and complementary spectroscopic parameters. The individual theoretical oscillation frequencies for the corresponding stellar models were obtained using GYRE as the pulsation code. A Bayesian approach was applied to find the probability distribution functions of the stellar parameters using AIMS (Asteroseismic Inference on a Massive Scale) as the optimisation code. The ages of HD 176465 A and HD 176465 B were found to be 2.81 $\\pm$ 0.48 Gyr and 2.52 $\\pm$ 0.80 Gyr, respectively. ...

  4. Gravitational Wave Physics with Binary Love Relations

    Science.gov (United States)

    Yagi, Kent; Yunes, Nicolas

    2016-03-01

    Gravitational waves from the late inspiral of neutron star binaries encode rich information about their internal structure at supranuclear densities through their tidal deformabilities. However, extracting the individual tidal deformabilities of the components of a binary is challenging with future ground-based gravitational wave interferometers due to degeneracies between them. We overcome this difficulty by finding new, approximate universal relations between the individual tidal deformabilities that depend on the mass ratio of the two stars and are insensitive to their internal structure. Such relations have applications not only to gravitational wave astrophysics, but also to nuclear physics as they improve the measurement accuracy of tidal parameters. Moreover, the relations improve our ability to test extreme gravity and perform cosmology with gravitational waves emitted from neutron star binaries.

  5. ON SELF-INVERSE BINARY MATRICES OVER THE BINARY GALOIS FIELD

    Directory of Open Access Journals (Sweden)

    Ali Muhammad Ali Rushdi

    2013-01-01

    Full Text Available An important class of square binary matrices over the simplest finite or Galois Field GF(2 is the class of involutory or Self-Inverse (SI matrices. These matrices are of significant utility in prominent engineering applications such as the study of the Preparata Transformation or the analysis of synchronous Boolean Networks. Therefore, it is essential to devise appropriate methods, not only for understanding the properties of these matrices, but also for characterizing and constructing them. We survey square binary matrices of orders 1, 2 and 3 to identify primitive SI matrices among them. Larger SI matrices are constructed as (a the direct sum, or (b the Kronecker product, of smaller ones. Illustrative examples are given to demonstrate the construction and properties of binary SI matrices. The intersection of the sets of SI and permutation binary matrices is studied. We also study higher-order SI binary matrices and describe them via recursive relations or Kronecker products. Our work culminates in an exposition of the two most common representations of Boolean functions via two types of Boolean SI matrices. A better understanding of the properties and methods of constructing SI binary matrices over GF (2 is achieved. A clearer picture is attained about the utility of binary matrices in the representation of Boolean functions.

  6. Searching for Binary Supermassive Black Holes via Variable Broad Emission Line Shifts: Low Binary Fraction

    Science.gov (United States)

    Wang, Lile; Greene, Jenny E.; Ju, Wenhua; Rafikov, Roman R.; Ruan, John J.; Schneider, Donald P.

    2017-01-01

    Supermassive black hole binaries (SMBHs) are expected to result from galaxy mergers, and thus are natural byproducts (and probes) of hierarchical structure formation in the universe. They are also the primary expected source of low-frequency gravitational wave emission. We search for binary BHs using time-variable velocity shifts in broad Mg ii emission lines of quasars with multi-epoch observations. First, we inspect velocity shifts of the binary SMBH candidates identified in Ju et al., using Sloan Digital Sky Survey spectra with an additional epoch of data that lengthens the typical baseline to ∼10 yr. We find variations in the line of sight velocity shifts over 10 yr that are comparable to the shifts observed over 1–2 yr, ruling out the binary model for the bulk of our candidates. We then analyze 1438 objects with eight-year median time baselines, from which we would expect to see velocity shifts >1000 {km} {{{s}}}-1 from sub-parsec binaries. We find only one object with an outlying velocity of 448 {km} {{{s}}}-1, indicating—based on our modeling—that ≲1% (the value varies with different assumptions) of SMBHs that are active as quasars reside in binaries with ∼0.1 pc separations. Binaries either sweep rapidly through these small separations or stall at larger radii.

  7. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

    2013-11-10

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

  8. VLSI binary multiplier using residue number systems

    Energy Technology Data Exchange (ETDEWEB)

    Barsi, F.; Di Cola, A.

    1982-01-01

    The idea of performing multiplication of n-bit binary numbers using a hardware based on residue number systems is considered. This paper develops the design of a VLSI chip deriving area and time upper bounds of a n-bit multiplier. To perform multiplication using residue arithmetic, numbers are converted from binary to residue representation and, after residue multiplication, the result is reconverted to the original notation. It is shown that the proposed design requires an area a=o(n/sup 2/ log n) and an execution time t=o(log/sup 2/n). 7 references.

  9. Binary Sparse Phase Retrieval via Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Wei Peng

    2016-01-01

    Full Text Available This paper presents the Simulated Annealing Sparse PhAse Recovery (SASPAR algorithm for reconstructing sparse binary signals from their phaseless magnitudes of the Fourier transform. The greedy strategy version is also proposed for a comparison, which is a parameter-free algorithm. Sufficient numeric simulations indicate that our method is quite effective and suggest the binary model is robust. The SASPAR algorithm seems competitive to the existing methods for its efficiency and high recovery rate even with fewer Fourier measurements.

  10. Spin supplementary conditions for spinning compact binaries

    CERN Document Server

    Mikóczi, Balázs

    2016-01-01

    We consider the different spin supplementary conditions (SSC) for a spinning compact binary with the leading-order spin-orbit (SO) interaction. The Lagrangian of the binary system can be constructed but it is acceleration-dependent in two cases of SSC. We rewrite the generalized Hamiltonian formalism proposed by Ostrogradsky and compute the conservative quantities and the dissipative part of relative motion during the gravitational radiation of each SSCs. We give the orbital elements and observed quantities of the SO dynamics, for instance the energy and the orbital angular momentum losses and waveforms and discuss their SSC dependence.

  11. Rotation and massive close binary evolution

    CERN Document Server

    Langer, N; Yoon, S -C; Hunter, I; Brott, I; Lennon, D J; de Mink, S E; Verheijdt, M

    2008-01-01

    We review the role of rotation in massive close binary systems. Rotation has been advocated as an essential ingredient in massive single star models. However, rotation clearly is most important in massive binaries where one star accretes matter from a close companion, as the resulting spin-up drives the accretor towards critical rotation. Here, we explore our understanding of this process, and its observable consequences. When accounting for these consequences, the question remains whether rotational effects in massive single stars are still needed to explain the observations.

  12. Speckle interferometric observations of close binary stars

    CERN Document Server

    Saha, S K; Yeswanth, L; Anbazhagan, P

    2002-01-01

    Speckle interferometric technique is employed to record a series of hundreds of short-exposure images of several close binary stars with sub-arcsecond separation through a narrow band filter at the Cassegrain focus of the 2.34 meter (m) Vainu Bappu telescope (VBT), situated at Vainu Bappu Observatory (VBO), Kavalur, India. The data are recorded sequentially by a Peltier-cooled intensified CCD camera with 10 ms exposure. The auto-correlation method is applied to determine the angular separations and position angles of these binary systems.

  13. Photometric Solutions of Some Contact ASAS Binaries

    CERN Document Server

    Gezer, I

    2015-01-01

    We present the first light curve solution of 6 contact binary systems which are chosen from the ASAS catalog. The photometric elements and the estimated absolute parameters of all systems are obtained with the light curve analyses. We calculated the values of degree of contact for the systems. The location of the targets on the Hertzsprung-Russell diagram and the mass-radius plane is compared to the other well-known contact binaries and the evolutionary status of the systems are also discussed.

  14. Photometric solutions of some contact ASAS binaries

    Science.gov (United States)

    Gezer, İ.; Bozkurt, Z.

    2016-04-01

    We present the first light curve solution of 6 contact binary systems which are chosen from the ASAS catalog. The photometric elements and the estimated absolute parameters of all systems are obtained with the light curve analyses. We calculated the values of degree of contact for the systems. The location of the targets on the Hertzsprung-Russell diagram and the mass-radius plane is compared to the other well-known contact binaries and the evolutionary status of the systems are also discussed.

  15. All optical binary delta-sigma modulator

    Science.gov (United States)

    Sayeh, Mohammad R.; Siahmakoun, Azad

    2005-09-01

    This paper describes a novel A/D converter called "Binary Delta-Sigma Modulator" (BDSM) which operates only with nonnegative signal with positive feedback and binary threshold. This important modification to the conventional delta-sigma modulator makes the high-speed (>100GHz) all-optical implementation possible. It has also the capability to modify its own sampling frequency as well as its input dynamic range. This adaptive feature helps designers to optimize the system performance under highly noisy environment and also manage the power consumption of the A/D converters.

  16. Pulsations in close binaries: challenges and opportunities

    Directory of Open Access Journals (Sweden)

    Maceroni C.

    2015-01-01

    Full Text Available CoRoT and Kepler provided a precious by-product: a number of eclipsing binaries containing variable stars and, among these, non-radial pulsators. This providential occurrence allows combining independent information from two different phenomena whose synergy yields scientific results well beyond those from the single sources. In particular, the analysis of pulsations in eclipsing binary components throws light on the internal structure of the pulsating star, on the system evolution, and on the role of tidal forces in exciting the oscillations. The case study of the Kepler target KIC 3858884 is illustrative of the difficulties of analysis and of the achievements in this rapidly developing field.

  17. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing...... masses of the brown dwarf companions are 0.02 ± 0.01 M⊙ and 0.019 ± 0.002 M⊙ for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events...

  18. Apsidal motion in eclipsing binary GG Orionis

    Science.gov (United States)

    Yilan, E.; Bulut, I.

    2016-03-01

    The study of apsidal motion in binary stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric eclipsing binary GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Giménez and García-Pelayo (1983) has been used for the apsidal motion analysis.

  19. Auto-correlation of Binary stars

    CERN Document Server

    Saha, S K

    2001-01-01

    Speckle interferometric technique is used to record a series of short exposure images of several close binary stars with sub-arcsecond separation through a narrow band filter centred at H$\\alpha$ at the Cassegrain focus of the 2.34 meter Vainu Bappu telescope (VBT), situated at Vainu Bappu Observatory (VBO), Kavalur. The auto-correlation method is developed under Image Reduction Analysis Facility (IRAF). Wiener filter is included in the programme to eliminate spurious high frequency contributions; a few sets of data provide the optimised results. The auto-correlated image of these stars gives the separation of the binary components.

  20. The DEBCat detached eclipsing binary catalogue

    CERN Document Server

    Southworth, John

    2014-01-01

    Detached eclipsing binary star systems are our primary source of measured physical properties of normal stars. I introduce DEBCat: a catalogue of detached eclipsing binaries with mass and radius measurements to the 2% precision necessary to put useful constraints on theoretical models of stellar evolution. The catalogue was begun in 2006, as an update of the compilation by Andersen (1991). It now contains over 170 systems, and new results are added on appearance in the refereed literature. DEBCat is available at: http://www.astro.keele.ac.uk/jkt/debcat/

  1. Winds from disks in compact binaries

    Energy Technology Data Exchange (ETDEWEB)

    Mauche, C.W.

    1993-10-27

    We herein present an observational and theoretical review of the winds of compact binaries. After a brief consideration of the accretion disk coronae and winds of X-ray binaries, the review concentrates on the winds of cataclysmic variables (CVs). Specifically, we consider the related problems of the geometry and mass-loss rate of the winds of CVs, their ionization state and variability, and the results from studies of eclipsing CVs. Finally, the properties of bona fide accretion disk wind models are reviewed.

  2. Linking gene regulation and the exo-metabolome: A comparative transcriptomics approach to identify genes that impact on the production of volatile aroma compounds in yeast

    Directory of Open Access Journals (Sweden)

    Bauer Florian F

    2008-11-01

    Full Text Available Abstract Background 'Omics' tools provide novel opportunities for system-wide analysis of complex cellular functions. Secondary metabolism is an example of a complex network of biochemical pathways, which, although well mapped from a biochemical point of view, is not well understood with regards to its physiological roles and genetic and biochemical regulation. Many of the metabolites produced by this network such as higher alcohols and esters are significant aroma impact compounds in fermentation products, and different yeast strains are known to produce highly divergent aroma profiles. Here, we investigated whether we can predict the impact of specific genes of known or unknown function on this metabolic network by combining whole transcriptome and partial exo-metabolome analysis. Results For this purpose, the gene expression levels of five different industrial wine yeast strains that produce divergent aroma profiles were established at three different time points of alcoholic fermentation in synthetic wine must. A matrix of gene expression data was generated and integrated with the concentrations of volatile aroma compounds measured at the same time points. This relatively unbiased approach to the study of volatile aroma compounds enabled us to identify candidate genes for aroma profile modification. Five of these genes, namely YMR210W, BAT1, AAD10, AAD14 and ACS1 were selected for overexpression in commercial wine yeast, VIN13. Analysis of the data show a statistically significant correlation between the changes in the exo-metabome of the overexpressing strains and the changes that were predicted based on the unbiased alignment of transcriptomic and exo-metabolomic data. Conclusion The data suggest that a comparative transcriptomics and metabolomics approach can be used to identify the metabolic impacts of the expression of individual genes in complex systems, and the amenability of transcriptomic data to direct applications of

  3. Elucidating the True Binary Fraction of VLM Stars and Brown Dwarfs with Spectral Binaries

    Science.gov (United States)

    Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Gelino, Christopher R.; SAHLMANN, JOHANNES; Schmidt, Sarah J.; Gagne, Jonathan; Skrzypek, Nathalie

    2017-01-01

    The very lowest-mass (VLM) stars and brown dwarfs are found in abundance in nearly all Galactic environments, yet their formation mechanism(s) remain an open question. One means of testing current formation theories is to use multiplicity statistics. The majority of VLM binaries have been discovered through direct imaging, and current angular resolution limits (0.05”-0.1") are coincident with the 1-4 AU peak in the projected separation distribution of known systems, suggesting an observational bias. I have developed a separation-independent method to detect T dwarf companions to late-M/early-L dwarfs by identifying methane absorption in their unresolved, low-resolution, near-infrared spectra using spectral indices and template fitting. Over 60 spectral binary candidates have been identified with this and comparable methods. I discuss follow-up observations, including laser-guide star adaptive optics imaging with Keck/NIRC2, which have confirmed 9 systems; and radial velocity and astrometric monitoring observations that have confirmed 7 others. The direct imaging results indicate a resolved binary fraction of 18%, coincident with current estimates of the VLM binary fraction; however, our sample contained 5 previously confirmed binaries, raising its true binary fraction to 47%. To more accurately measure the true VLM binary fraction, I describe the construction of an unbiased, volume-limited, near-infrared spectral sample of M7-L5 dwarfs within 25 pc, of which 4 (1%) are found to be spectral binary candidates. I model the complex selection biases of this method through a population simulation, set constraints on the true binary fraction as traced by these systems, and compare to the predictions of current formation theories. I also describe how this method may be applied to conduct a separation-unbiased search for giant exoplanets orbiting young VLM stars and brown dwarfs.

  4. Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

    Science.gov (United States)

    Fryer, Chris L; Oliveira, F G; Rueda, J A; Ruffini, R

    2015-12-01

    Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52}  erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

  5. Accretion-powered Compact Binaries

    Science.gov (United States)

    Mauche, Christopher W.

    2003-12-01

    Preface; The workshop logo; A short history of the CV workshop F. A. Córdova; Part I. Observations: 1. Low mass x-ray binaries A. P. Cowley, P. C. Schmidtke, D. Crampton, J. B. Hutchings, C. A. Haswell, E. L. Robinson, K. D. Horne, H. M. Johnston, S. R. Kulkarni, S. Kitamoto, X. Han, R. M. Hjellming, R. M. Wagner, S. L. Morris, P. Hertz, A. N. Parmar, L. Stella, P. Giommi, P. J. Callanan, T. Naylor, P. A. Charles, C. D. Bailyn, J. N. Imamura, T. Steiman-Cameron, J. Kristian, J. Middleditch, L. Angelini and J. P. Noris; 2. Nonmagnetic cataclysmic variables R. S. Polidan, C. W. Mauche, R. A. Wade, R. H. Kaitchuck, E. M. Schlegel, P. A. Hantzios, R. C. Smith, J. H. Wood, F. Hessman, A. Fiedler, D. H. P. Jones, J. Casares, P. A. Charles, J. van Paradijs, E. Harlaftis, T. Naylor, G. Sonneborn, B. J. M. Hassall, K. Horne, C. A. la Dous, A. W. Shafter, N. A. Hawkins, D. A. H. Buckley, D. J. Sullivan, F. V. Hessman, V. S. Dhillon, T. R. Marsh, J. Singh, S. Seetha, F. Giovannelli, A. Bianchini, E. M. Sion, D. J. Mullan, H. L. Shipman, G. Machin, P. J. Callanan, S. B. Howell, P. Szkody, E. M. Schlegel and R. F. Webbink; 3. Magnetic cataclysmic variables C. Hellier, K. O. Mason, C. W. Mauche, G. S. Miller, J. C. Raymond, F. K. Lamb, J. Patterson, A. J. Norton, M. G. Watson, A. R. King, I. M. McHardy, H. Lehto, J. P. Osborne, E. L. Robinson, A. W. Shafter, S. Balachandran, S. R. Rosen, J. Krautter, W. Buchholz, D. A. H. Buckley, I. R. Tuoly, D. Crampton, B. Warner, R. M. Prestage, B. N. Ashoka, M. Mouchet, J. M. Bonnet-Bidaud, J. M. Hameury, P. Szkody, P. Garnavich, S. Howell, T. Kii, M. Cropper, K. Mason, J. Bailey, D. T. Wickramasinghe, L. Ferrario, K. Beuermann, A. D. Schwope, H.-C. Thomas, S. Jordan, J. Schachter, A. V. Filippenko, S. M. Kahn, F. B. S. Paerels, K. Mukai, M. L. Edgar, S. Larsson, R. F. Jameson, A. R. King, A. Silber, R. Remillard, H. Bradt, M. Ishida, T. Ohashi and G. D. Schmidt; Part II. Accretion Theory: 4. Nonmagnetic W. Kley, F. Geyer, H. Herold, H

  6. The Tarantula Massive Binary Monitoring. I. Observational campaign and OB-type spectroscopic binaries

    Science.gov (United States)

    Almeida, L. A.; Sana, H.; Taylor, W.; Barbá, R.; Bonanos, A. Z.; Crowther, P.; Damineli, A.; de Koter, A.; de Mink, S. E.; Evans, C. J.; Gieles, M.; Grin, N. J.; Hénault-Brunet, V.; Langer, N.; Lennon, D.; Lockwood, S.; Maíz Apellániz, J.; Moffat, A. F. J.; Neijssel, C.; Norman, C.; Ramírez-Agudelo, O. H.; Richardson, N. D.; Schootemeijer, A.; Shenar, T.; Soszyński, I.; Tramper, F.; Vink, J. S.

    2017-02-01

    Context. Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way. Aims: The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region. Methods: In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries. Results: Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus's core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2-O7) tend to have shorter orbital periods than later spectral types (O9.2-O9.7). Conclusions: Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the

  7. Titanocene(III)-catalyzed 6-exo versus 7-endo cyclizations of epoxypolyprenes: efficient control and synthesis of versatile terpenic building blocks.

    Science.gov (United States)

    Justicia, José; Jiménez, Tania; Miguel, Delia; Contreras-Montoya, Rafael; Chahboun, Rachid; Alvarez-Manzaneda, Enrique; Collado-Sanz, Daniel; Cárdenas, Diego J; Cuerva, Juan M

    2013-10-18

    In this article, a complete study on the selectivity of titanocene(III) cyclization of epoxypolyprenes is presented. The requirements for the formation of six- or seven-membered rings during these cyclizations are determined, taking into account the different substitution pattern in the epoxypolyprene precursor. Thus, a complete selectivity to 6-exo or 7-endo cyclization process has been achieved, yielding mono-, bi-, and even tricyclic compounds, constituting a new and efficient access to this type of derivative. Additionally, this procedure opens the possibility to prepare excellent building blocks for the synthesis of polycyclic compounds with a trisubstituted oxygenated function, which is present in several natural terpenes.

  8. CARMENES: Calar Alto high-Resolution search for M dwarfs with Exo-earths with a Near-infrared Echelle Spectrograph

    CERN Document Server

    Quirrenbach, A; Mandel, H; Caballero, J A; Ribas, I; Reiners, A; Mundt, R; Abril, M; Afonso, C; Bean, J L; Bejar, V J S; Becerril, S; Boehm, A; Cardenas, C; Claret, A; Colome, J; Costillo, L P; Dreizler, S; Fernandez, M; Francisco, X; Garrido, R; Hernandez, J I Gonzalez; Guenther, E W; Gutierrez-Soto, J; Joergens, V; Hatzes, A P; Henning, T; Herrero, E; Kurster, M; Laun, W; Lenzen, R; Mall, U; Martin, E L; Martin-Ruiz, S; Montes, D; Morales, J C; Munoz, R Morales; Moya, A; Naranjo, V; Rabaza, O; Ramon, A; Rebolo, R; Reffert, S; Rodler, F; Rodriguez, E; Trinidad, A Rodriguez; Rohloff, R -R; Carrasco, M A Sanchez; Schmidt, C; Seifert, W; Setiawan, J; Stahl, O; Suarez, J C; Wiedemann, G; del Burgo, C; Galadi, D; Sanchez-Blanco, E; Xu, W

    2009-01-01

    CARMENES, Calar Alto high-Resolution search for M dwarfs with Exo-earths with a Near-infrared Echelle Spectrograph, is a study for a next-generation instrument for the 3.5m Calar Alto Telescope to be designed, built, integrated, and operated by a consortium of nine German and Spanish institutions. Our main objective is finding habitable exoplanets around M dwarfs, which will be achieved by radial velocity measurements on the m/s level in the near-infrared, where low-mass stars emit the bulk of their radiation.

  9. SINBAD electronic models of the interface and control system for the NOMAD spectrometer on board of ESA ExoMars Trace Gas Orbiter mission

    Science.gov (United States)

    Jerónimo Zafra, José M.; Sanz Mesa, Rosario; Gómez López, Juan M.; Rodríguez Gómez, Julio F.; Aparicio del Moral, Beatriz; Morales Muñoz, Rafael; Candini, Gian Paolo; Pastor Morales, M. Carmen; Robles Muñoz, Nicolás.; López-Moreno, José Juan; Vandaele, Ann Carine; Neefs, Eddy; Drummond, Rachel; Delanoye, Sofie; Berkenbosch, Sophie; Clairquin, Roland; Ristic, Bojan; Maes, Jeroen; Bonnewijn, Sabrina; Patel, Manish R.; Leese, Mark

    2016-07-01

    NOMAD is a spectrometer suite: UV-visible-IR spectral ranges. NOMAD is part of the payload of ESA ExoMars Trace Gas Orbiter Mission. SINBAD boards are in charge of the communication and management of the power and control between the spacecraft and the instrument channels. SINBAD development took four years, while the entire development and test required five years, a very short time to develop an instrument devoted to a space mission. The hardware of SINBAD is shown in the attached poster: developed boards, prototype boards and final models. The models were delivered to the ESA in order to testing and integration with the spacecraft.

  10. BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Reipurth, Bo [Institute for Astronomy and NASA Astrobiology Institute University of Hawaii, 640 N. Aohoku Place, Hilo, HI 96720 (United States); Mikkola, Seppo, E-mail: reipurth@ifa.hawaii.edu, E-mail: Seppo.Mikkola@utu.fi [Tuorla Observatory, University of Turku, Väisäläntie 20, Piikkiö (Finland)

    2015-04-15

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  11. Model-independent inference on compact-binary observations

    Science.gov (United States)

    Mandel, Ilya; Farr, Will M.; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2017-03-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multidimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed neutron star-black hole binaries with tens of observations.

  12. The same, but different: Stochasticity in binary destruction

    CERN Document Server

    Parker, Richard J

    2012-01-01

    Observations of binaries in clusters tend to be of visual binaries with separations of 10s - 100s au. Such binaries are 'intermediates' and their destruction or survival depends on the exact details of their individual dynamical history. We investigate the stochasticity of the destruction of such binaries and the differences between the initial and processed populations using N-body simulations. We concentrate on Orion Nebula Cluster-like clusters, where the observed binary separation distribution ranges from 62 - 620 au. We find that, starting from the same initial binary population in statistically identical clusters, the number of intermediate binaries that are destroyed after 1 Myr can vary by a factor of >2, and that the resulting separation distributions can be statistically completely different in initially substructured clusters. We also find that the mass ratio distributions are altered (destroying more low mass ratio systems), but not as significantly as the binary fractions or separation distributi...

  13. Observational Evidence for Tidal Interaction in Close Binary Systems

    CERN Document Server

    Mazeh, Tsevi

    2008-01-01

    This paper reviews the rich corpus of observational evidence for tidal effects in short-period binaries. We review the evidence for ellipsoidal variability and for the observational manifestation of apsidal motion in eclipsing binaries. Among the long-term effects, circularization was studied the most, and a transition period between circular and eccentric orbits has been derived for eight coeval samples of binaries. As binaries are supposed to reach synchronization before circularization, one can expect finding eccentric binaries in pseudo-synchronization state, the evidence for which is reviewed. The paper reviews the Rossiter-McLaughlin effect and its potential to study spin-orbit alignment. We discuss the tidal interaction in close binaries that are orbited by a third distant companion, and review the effect of pumping the binary eccentricity by the third star. We then discuss the idea that the tidal interaction induced by the eccentricity modulation can shrink the binary separation. The paper discusses t...

  14. Evolution of Binary Stars in Multiple-Population Globular Clusters

    CERN Document Server

    Hong, Jongsuk; Sollima, Antonio; McMillan, Stephen L W; D'Antona, Franca; D'Ercole, Annibale

    2015-01-01

    The discovery of multiple stellar populations in globular clusters has implications for all the aspects of the study of these stellar systems. In this paper, by means of N-body simulations, we study the evolution of binary stars in multiple-population clusters and explore the implications of the initial differences in the spatial distribution of different stellar populations for the evolution and survival of their binary stars. Our simulations show that initial differences between the spatial distribution of first-generation (FG) and second-generation (SG) stars can leave a fingerprint in the current properties of the binary population. SG binaries are disrupted more efficiently than those of the FG population resulting in a global SG binary fraction smaller than that of the FG. As for surviving binaries, dynamical evolution produces a difference between the SG and the FG binary binding energy distribution with the SG population characterized by a larger fraction of high binding energy (more bound) binaries. ...

  15. On the dynamical evolution and end states of binary centaurs

    Science.gov (United States)

    Brunini, A.

    2014-01-01

    In this paper, we perform a numerical integration of 666 fictitious binary Centaurs coming from the trans Neptunian space. Our population is restricted to tight binaries whose components have sizes between 30 and 100 km. We included the dynamical perturbations from the giant planets, Kozai Cycles induced by the Sun and tidal friction on the orbits of the binaries. We found that most binaries are disrupted during one of the close planetary encounters, making the mean lifetime of binary Centaurs much shorter than the one of single Centaurs. Nearly 10 per cent of the binaries reach a very tight circular orbit, arguing in favour of the existence of a non-negligible population of contact Centaurs. Another 10 per cent survive as a binary during their lifetime as Centaur. Our simulations favour the existence of a small population of very tight binary Centaurs.

  16. Model-independent inference on compact-binary observations

    CERN Document Server

    Mandel, Ilya; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2016-01-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multi-dimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed black hole -- neutron star binaries.

  17. Model-independent inference on compact-binary observations

    OpenAIRE

    Mandel, Ilya; Farr, Will M.; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2016-01-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multi-dimensional parameter space of observations t...

  18. The cool surfaces of binary near-Earth asteroids

    OpenAIRE

    Delbo, Marco; Walsh, Kevin; Mueller, Michael; Harris, Alan W.; Howell, Ellen S.

    2011-01-01

    Abstract Here we show results from thermal-infrared observations of km-sized binary Near-Earth Asteroids (NEAs). We combine previously published thermal properties for NEAs with newly derived values for three binary NEAs. The ?value derived from the Near-Earth Asteroid Thermal Model (NEATM) for each object is then used to estimate an average thermal inertia for the population of binary NEAs and compared against similar estimates for the population of non-binaries. We find that thes...

  19. Formation and evolution of X-ray binaries

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We review recent progress in theoretical understanding of X-ray binaries,which has largely been driven by new observations.We select several topics including formation of compact low-mass X-ray binaries,the evolutionary connection between low-mass X-ray binaries and binary and millisecond radio pulsars,and ultraluminous X-ray sources,to illustrate the interplay between theories and observations.

  20. Beyond-Binary Arithmetic: Algorithms and VLSI Implementations

    OpenAIRE

    Aoki, Takafumi; Higuchi, Tatsuo

    2000-01-01

    Beyond-binary arithmetic algorithms are defined as a new class of computer arithmetic algorithms which employ non-binary data representations to achieve higher performances beyond those of conventional binary algorithms. This paper presents prominent examples of beyond-binary arithmetic algorithms: examples include (i) a high-radix redundant division algorithm without using lookup tables, (ii) a high-radix redundant CORDIC algorithm for fast vector rotation, and (iii) redundant complex arithm...

  1. Predicting Social Trust with Binary Logistic Regression

    Science.gov (United States)

    Adwere-Boamah, Joseph; Hufstedler, Shirley

    2015-01-01

    This study used binary logistic regression to predict social trust with five demographic variables from a national sample of adult individuals who participated in The General Social Survey (GSS) in 2012. The five predictor variables were respondents' highest degree earned, race, sex, general happiness and the importance of personally assisting…

  2. The Benchmark Eclipsing Binary V530 Ori

    DEFF Research Database (Denmark)

    Torres, Guillermo; Lacy, Claud H. Sandberg; Pavlovski, Kresimir

    2015-01-01

    We report accurate measurements of the physical properties (mass, radius, temperature) of components of the G+M eclipsing binary V530 On. The M-type secondary shows a larger radius and a cooler temperature than predicted by standard stellar evolution models, as has been found for many other low...

  3. Testing the Binary Trigger Hypothesis in FUors

    CERN Document Server

    Green, Joel D; Rizzuto, Aaron C; Ireland, Michael J; Dupuy, Trent J; Mann, Andrew W; Kuruwita, Rajika

    2016-01-01

    We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry (NRM) at 1.59 um and 2.12 um that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit (rho = 58.3 +/- 1.4 mas or 30 +/- 5 AU) and currently much fainter than the outbursting star (delta(K') = 3.34 +/- 0.10 mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion (M ~ 0.25 Msun) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of delta(K') ~ 4 mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary ...

  4. Spectropolarimetry of single and binary stars

    CERN Document Server

    Harries, T J

    2004-01-01

    Spectropolarimetry is a photon-hungry technique that will reach fruition in the 8-m telescope age. Here I summarize some of the stellar spectropolarimetric research that my collaborators and I have undertaken, with particular emphasis on the circumstellar environment of massive stars, symbiotic binaries, and star formation.

  5. Binaries are the best single stars

    NARCIS (Netherlands)

    de Mink, S.E.; Langer, N.; Izzard, R.G.

    2010-01-01

    Stellar models of massive single stars are still plagued by major uncertainties. Testing and calibrating against observations is essential for their reliability. For this purpose one preferably uses observed stars that have never experienced strong binary interaction, i.e. “true single stars”. Howev

  6. Cassini states for black-hole binaries

    CERN Document Server

    Correia, Alexandre C M

    2016-01-01

    Cassini states correspond to equilibria of the spin axis of a celestial body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black-hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black-hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black-hole binary systems based on a Hamiltonian formalism. In absence of dissipation the problem is integrable and it is easy to identify all possible trajectories for the spin for a given value of the total angular momentum. As the system collapses due to radiation reaction, the Cassini states are shifted to different positions, which modifies the dynamics around them. This is why the final spin distribution may differ from the initial one. Our method provides a simple way of predicting the distribution of the spin of black-hole binaries at th...

  7. Bloch-Zener oscillations in binary superlattices.

    Science.gov (United States)

    Dreisow, F; Szameit, A; Heinrich, M; Pertsch, T; Nolte, S; Tünnermann, A; Longhi, S

    2009-02-20

    Bloch-Zener oscillations, i.e., the coherent superposition of Bloch oscillations and Zener tunneling between minibands of a binary lattice, are experimentally demonstrated for light waves in curved femtosecond laser-written waveguide arrays. Visualization of double-periodicity breathing and oscillation modes is reported, and synchronous tunneling leading to wave reconstruction is demonstrated.

  8. Testing the Binary Trigger Hypothesis in FUors

    Science.gov (United States)

    Green, Joel D.; Kraus, Adam L.; Rizzuto, Aaron C.; Ireland, Michael J.; Dupuy, Trent J.; Mann, Andrew W.; Kuruwita, Rajika

    2016-10-01

    We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry at 1.59 μm and 2.12 μm that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit (ρ =58.3+/- 1.4 mas or 30 ± 5 au) and currently much fainter than the outbursting star ({{Δ }}K\\prime =3.34+/- 0.10 mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion (M∼ 0.25{M}ȯ ) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of {{Δ }}K\\prime ∼ 4 mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary companion. However, we argue from the system geometry and mass reservoir considerations that these outbursts are not directly tied to the orbital period (i.e., occurring at periastron passage), but instead must only occur infrequently.

  9. Flip-flopping binary black holes.

    Science.gov (United States)

    Lousto, Carlos O; Healy, James

    2015-04-10

    We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of d≈25M between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for t=20 000M and displays a total change in the orientation of the spin of one of the black holes from an initial alignment with the orbital angular momentum to a complete antialignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 post-Newtonian equations of motion and spin evolution to show that this process continuously flip flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.

  10. Binaries are the best single stars

    CERN Document Server

    de Mink, S E; Izzard, R G

    2010-01-01

    Stellar models of massive single stars are still plagued by major uncertainties. Testing and calibrating against observations is essential for their reliability. For this purpose one preferably uses observed stars that have never experienced strong binary interaction, i.e. "true single stars". However, the binary fraction among massive stars is high and identifying "true single stars" is not straight forward. Binary interaction affects systems in such a way that the initially less massive star becomes, or appears to be, single. For example, mass transfer results in a widening of the orbit and a decrease of the luminosity of the donor star, which makes it very hard to detect. After a merger or disruption of the system by the supernova explosion, no companion will be present. The only unambiguous identification of "true single stars" is possible in detached binaries, which contain two main-sequence stars. For these systems we can exclude the occurrence of mass transfer since their birth. A further advantage is ...

  11. Binary pulsars as dark-matter probes

    CERN Document Server

    Pani, Paolo

    2015-01-01

    During the motion of a binary pulsar around the galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a characteristic seasonal modulation of the orbit and causes a secular change of the orbital period whose magnitude can be well within the astonishing precision of various binary-pulsar observations. Our analysis is valid for binary systems with orbital period longer than a day. By comparing this effect with pulsar-timing measurements, it is possible to derive model-independent upper bounds on the dark-matter density at different distances $D$ from the galactic center. For example, the precision timing of J1713+0747 imposes $\\rho_{\\rm DM}\\lesssim 10^5\\,{\\rm GeV/cm}^3$ at $D\\approx7\\,{\\rm kpc}$. The detection of a binary pulsar at $D\\lesssim 10\\,{\\rm pc}$ could provide stringent constraints on dark-matter halo profiles and on growth models of the central black hole. The Square Kil...

  12. LSM is not generated by binary functions

    CERN Document Server

    McQuillan, Colin

    2011-01-01

    Bulatov et al. [1] defined the operation of (efficient) pps_\\omega-definability in order to study the computational complexity of certain approximate counting problems. They asked whether all log-supermodular functions can be defined by binary implication and unary functions in this sense. We give a negative answer to this question.

  13. Binary Solid-Liquid Phase Equilibria

    Science.gov (United States)

    Ellison, Herbert R.

    1978-01-01

    Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)

  14. The Orbital Decay of Embedded Binary Stars

    CERN Document Server

    Stahler, Steven W

    2009-01-01

    Young binaries within dense molecular clouds are subject to dynamical friction from ambient gas. Consequently, their orbits decay, with both the separation and period decreasing in time. A simple analytic expression is derived for this braking torque. The derivation utilizes the fact that each binary acts as a quadrupolar source of acoustic waves. The acoustic disturbance has the morphology of a two-armed spiral and carries off angular momentum. From the expression for the braking torque, the binary orbital evolution is also determined analytically. This type of merger may help explain the origin of high-mass stars. If infrared dark clouds, with peak densities up to 10^7 cm^{-3}, contain low-mass binaries, those with separations less than 100 AU merge within about 10^5 yr. During the last few thousand years of the process, the rate of mechanical energy deposition in the gas exceeds the stars' radiative luminosity. Successive mergers may lead to the massive star formation believed to occur in these clouds.

  15. Binary translation using peephole translation rules

    Science.gov (United States)

    Bansal, Sorav; Aiken, Alex

    2010-05-04

    An efficient binary translator uses peephole translation rules to directly translate executable code from one instruction set to another. In a preferred embodiment, the translation rules are generated using superoptimization techniques that enable the translator to automatically learn translation rules for translating code from the source to target instruction set architecture.

  16. Orbits of Ten Visual Binary Stars

    Institute of Scientific and Technical Information of China (English)

    B.Novakovi(c)

    2007-01-01

    We present the orbits of ten visual binary stars:WDS 01015+6922.WDS 01424-0645,WDS 01461+6349,WDS 04374-0951,WDS 04478+5318,WDS 05255-0033,WDS 05491+6248,WDS 06404+4058,WDS 07479-1212,and WDS 18384+0850.We have also determined their masses,dynamical parallaxes and ephemerides.

  17. Chandra Imaging of Gamma-Ray Binaries

    CERN Document Server

    Kargaltsev, Oleg; Hare, Jeremy; Pavlov, George G

    2013-01-01

    We review the multiwavelength properties of the few known gamma-ray binaries, focusing on extended emission recently resolved with Chandra. We discuss the implications of these findings for the nature of compact objects and for physical processes operating in these systems.

  18. DARPA/TTO program IR binary optics

    Science.gov (United States)

    Veldkamp, W. B.

    1984-06-01

    Binary grating optics consist of microfine rectangular (high-low) relief patterns on a dielectric or a metallic surface. By controlling the depth, width and periodicity of the binary pattern, the amplitude and the phase of an electromagnetic wave can be controlled to produce a variety of optical transfer functions. The lithographic tools for fabrication of binary optics are the ones developed for VLSI circuit fabrication. From a single lithographic mask, planar replica optics can be made in quantity. This technology has broad applicability for tactical missile systems as well as for space systems. In addition to making optics cheaper than by conventional means, binary optics allows the fabrication of unique devices that cannot be made conventionally. These include high-speed rotary scanners, multiplexers, filters, beam shapers and coherent laser adders. The goal of this program is the development of high quality planar optical components using VLSI circuit fabrication techniques. The main elements of the plan are: (1) the development of large aperture segmented and piezoelectrically active planar optical surfaces, (2) the development of raster scanning laser telescopes and extension to broadband applications, and (3) the application of diffractive optics technology to the coherent addition of beams from modular laser systems. This report covers progress in the setup of a reactive ion-beam etching laboratory, and the feasibility demonstrations of the coherent beam addition concept with gas lasers.

  19. Runaway Massive Binaries and Cluster Ejection Scenarios

    CERN Document Server

    McSwain, M V; Boyajian, T S; Grundstrom, E D; Roberts, M S E; Ransom, Scott M.; Boyajian, Tabetha S.; Grundstrom, Erika D.

    2006-01-01

    The production of runaway massive binaries offers key insights into the evolution of close binary stars and open clusters. The stars HD 14633 and HD 15137 are rare examples of such runaway systems, and in this work we investigate the mechanism by which they were ejected from their parent open cluster, NGC 654. We discuss observational characteristics that can be used to distinguish supernova ejected systems from those ejected by dynamical interactions, and we present the results of a new radio pulsar search of these systems as well as estimates of their predicted X-ray flux assuming that each binary contains a compact object. Since neither pulsars nor X-ray emission are observed in these systems, we cannot conclude that these binaries contain compact companions. We also consider whether they may have been ejected by dynamical interactions in the dense environment where they formed, and our simulations of four-body interactions suggest that a dynamical origin is possible but unlikely. We recommend further X-ra...

  20. ANGULAR-MOMENTUM IN BINARY SPIRAL GALAXIES

    NARCIS (Netherlands)

    OOSTERLOO, T

    1993-01-01

    In order to investigate the relative orientations of spiral galaxies in pairs, the distribution of the angle between the spin-vectors for a new sample of 40 binary spiral galaxies is determined. From this distribution it is found, contrary to an earlier result obtained by Helou (1984), that there is