Systematic errors and combination of individual CRF solutions in the framework of the international pilot project for the next ICRF

A new international Pilot Project for the re-determination of the ICRF was initiated by the International VLBI Service for Geodesy and Astrometry (IVS) in January 2005. The purpose of this project is to compare the individual CRF solutions and to analyze their systematic and random errors with focus on the selection of the optimal strategy for the next ICRF realization. Eight radio source catalogues provided by the IVS Analysis Centers GA, SHAO, DGFI, GIUB-BKG, JPL, MAO NANU, GSFC, USNO were analyzed. In present study, four analytical models were used to investigate the systematic differences between solutions: solid rotation, rotation and deformation (IERS method), and expansion in orthogonal functions: Legendre-Fourier polynomials and spherical functions. It was found that expansions by orthogonal function describe the differences between individual catalogues better than the two former models. Finally, the combined CRF was generated. Using the radio source positions from this combined catalogue for estimation of EOP has shown improvement of the uncertainty of the celestial pole offset time series.Comment: 9 pages, 8 figures. Presented at the XXVIth IAU General Assembly, JD16, Prague, Czech Republic, 14-25 August 200

Clinical observations and management of a severe equine herpesvirus type 1 outbreak with abortion and encephalomyelitis

Latent equine herpesvirus type 1 (EHV-1) infection is common in horse populations worldwide and estimated to reach a prevalence nearing 90% in some areas. The virus causes acute outbreaks of disease that are characterized by abortion and sporadic cases of myeloencephalopathy (EHM), both severe threats to equine facilities. Different strains vary in their abortigenic and neuropathogenic potential and the simultaneous occurrence of EHM and abortion is rare. In this report, we present clinical observations collected during an EHV-1 outbreak caused by a so-called "neuropathogenic" EHV-1 G(2254)/D(752) polymerase (Pol) variant, which has become more prevalent in recent years and is less frequently associated with abortions. In this outbreak with 61 clinically affected horses, 6/7 pregnant mares aborted and 8 horses developed EHM. Three abortions occurred after development of EHM symptoms. Virus detection was performed by nested PCR targeting gB from nasal swabs (11 positive), blood serum (6 positive) and peripheral blood mononuclear cells (9 positive) of a total of 42 horses sampled. All 6 fetuses tested positive for EHV-1 by PCR and 4 by virus isolation. Paired serum neutralization test (SNT) on day 12 and 28 after the index case showed a significant (≥ 4-fold) increase in twelve horses (n = 42; 28.6%). This outbreak with abortions and EHM cases on a single equine facility provided a unique opportunity for the documentation of clinical disease progression as well as diagnostic procedures

Homogenization in compiling ICRF combined catalogs

Context. The International Astronomical Union (IAU) recommendations regarding the International Celestial Reference Frame (ICRF) realizations require the construction of radio sources catalogs obtained using very-long-baseline interferometry (VLBI) methods. The improvement of these catalogs is a necessary procedure for the further densification of the ICRF over the celestial sphere. Aims. The different positions obtained from several catalogs using common sources to the ICRF make it necessary to critically revise the different methods employed in improving the ICRF from several radio sources catalogs. In this sense, a revision of the analytical and the statistical methods is necessary in line with their advantages and disadvantages. We have a double goal: first, we propose an adequate treatment of the residual of several catalogs to obtain a homogeneous catalog; second, we attempt to discern whether a combined catalog is homogeneous. Methods. We define homogeneity as applied to our problem in a dual sense: the first deals with the spatial distribution of the data over the celestial sphere. The second has a statistical meaning, as we consider that homogeneity exists when the residual between a given catalog and the ICRF behaves as a unimodal pure Gaussian. We use a nonparametrical method, which enables us to homogeneously extend the statistical properties of the residual over the entire sphere. This intermediate adjustment allows for subsequent computation of the coefficients for any parametrical adjustment model that has a higher accuracy and greater stability, and it prevents problems related with direct adjustments using the models. On the other hand, the homogeneity of the residuals in a catalog is tested using different weights. Our procedure also serves to propose the most suitable weights to maintain homogeneity in the final results. We perform a test using the ICRF-Ext2, JPL, and USNO quasar catalogs. Results. We show that a combination of catalogs can only be homogeneous if we configure the weights carefully. In addition, we provide a procedure to detect inhomogeneities, which could introduce deformities, in these combined catalogs. Conclusions. An inappropriate use of analytical adjustment methods provides erroneous results. Analogously, it is not possible to obtain homogeneous-combined catalogs unless we use the adequate weights.Part of this work was supported by a grant P1-1B2009-07 from Fundacio Caixa Castello BANCAIXA and a grant P1-061I455.01/1 from Bancaja.Marco Castillo, FJ.; Martínez Uso, MJ.; Lopez Orti, JA. (2013). Homogenization in compiling ICRF combined catalogs. Astronomy and Astrophysics. 558(1):1-10. https://doi.org/10.1051/0004-6361/201321995S1105581Arias, E. F., Feissel, M., & Lestrade, J. 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The Astronomical Journal, 127(6), 3587-3608. doi:10.1086/420998Fey, A., Gordon, D., & Jacobs, C. 2009, IERS Technical Note 35, The Second realization of the International Celestial Reference Frame by Very Long Baseline Interferometry, Frankfurt am Main 2010: Verlag des Bundesamts für Kartographie und GeodäsieIERS 1999, 1998 IERS Annual Report, Observatoire de Paris, D. Gambis (Editor)Heiskanen, W. A., & Moritz H. 1967, Physical Geodesy (San Francisco: Freeman)Ma, C., Arias, E. F., Eubanks, T. M., Fey, A. L., Gontier, A.-M., Jacobs, C. S., … Charlot, P. (1998). The International Celestial Reference Frame as Realized by Very Long Baseline Interferometry. The Astronomical Journal, 116(1), 516-546. doi:10.1086/300408Marco, F. J., Martínez, M. J., & López, J. A. (2004). A critical discussion on parametric and nonparametric regression methods applied to Hipparcos-FK5 residuals. Astronomy & Astrophysics, 418(3), 1159-1170. doi:10.1051/0004-6361:20034441Marco, F. J., Martnez, M. J., & Lpez, J. A. (2004). Analysis of Systematic Differences of Astrometric Catalogs in a Band. The Astronomical Journal, 127(1), 549-559. doi:10.1086/380235Sfikas et al. 2005, in ICANN 2005, LNCS 3697, eds. W. Duch et al., 835Sokolova, J., & Malkin, Z. (2007). On comparison and combination of catalogues of radio source positions. Astronomy & Astrophysics, 474(2), 665-670. doi:10.1051/0004-6361:20077450Walter, S., & Sovers, O. J. 2000, Astrometry of fundamental catalogs. The evolution from optical to radio reference frames (Berlin: Springer-Verlag)Wand, M. P., & Jones, M. C. 1995, Kernel Smoothing (London: Chapman and Hall)Yatskiv, YA S., & Kuryakova. 1990, in Inertial Coordinate System on the Sky, Proc. 141th, eds. J.H. Lieske, & V. K. Abalakin, IAU Symp., 295Yu, M., Manchester, R. N., Hobbs, G., Johnston, S., Kaspi, V. M., Keith, M., … Xu, R. X. (2012). Detection of 107 glitches in 36 southern pulsars. 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Accurate prediction of kinase-substrate networks using knowledge graphs

Phosphorylation of specific substrates by protein kinases is a key control mechanism for vital cell-fate decisions and other cellular processes. However, discovering specific kinasesubstrate relationships is time-consuming and often rather serendipitous. Computational predictions alleviate these challenges, but the current approaches suffer from limitations like restricted kinome coverage and inaccuracy. They also typically utilise only local features without reflecting broader interaction context. To address these limitations, we have developed an alternative predictive model. It uses statistical relational learning on top of phosphorylation networks interpreted as knowledge graphs, a simple yet robust model for representing networked knowledge. Compared to a representative selection of six existing systems, our model has the highest kinome coverage and produces biologically valid highconfidence predictions not possible with the other tools. Specifically, we have experimentally validated predictions of previously unknown phosphorylations by the LATS1, AKT1, PKA and MST2 kinases in human. Thus, our tool is useful for focusing phosphoproteomic experiments, and facilitates the discovery of new phosphorylation reactions. Our model can be accessed publicly via an easy-to-use web interface (LinkPhinder).Science Foundation Irelan

Accurate prediction of kinase-substrate networks using knowledge graphs

Phosphorylation of specific substrates by protein kinases is a key control mechanism for vital cell-fate decisions and other cellular processes. However, discovering specific kinase-substrate relationships is time-consuming and often rather serendipitous. Computational predictions alleviate these challenges, but the current approaches suffer from limitations like restricted kinome coverage and inaccuracy. They also typically utilise only local features without reflecting broader interaction context. To address these limitations, we have developed an alternative predictive model. It uses statistical relational learning on top of phosphorylation networks interpreted as knowledge graphs, a simple yet robust model for representing networked knowledge. Compared to a representative selection of six existing systems, our model has the highest kinome coverage and produces biologically valid high-confidence predictions not possible with the other tools. Specifically, we have experimentally validated predictions of previously unknown phosphorylations by the LATS1, AKT1, PKA and MST2 kinases in human. Thus, our tool is useful for focusing phosphoproteomic experiments, and facilitates the discovery of new phosphorylation reactions. Our model can be accessed publicly via an easy-to-use web interface (LinkPhinder).Phosphorylation of specific substrates by protein kinases is a key control mechanism for vital cell-fate decisions and other cellular processes. However, discovering specific kinase-substrate relationships is time-consuming and often rather serendipitous. Computational predictions alleviate these challenges, but the current approaches suffer from limitations like restricted kinome coverage and inaccuracy. They also typically utilise only local features without reflecting broader interaction context. To address these limitations, we have developed an alternative predictive model. It uses statistical relational learning on top of phosphorylation networks interpreted as knowledge graphs, a simple yet robust model for representing networked knowledge. Compared to a representative selection of six existing systems, our model has the highest kinome coverage and produces biologically valid high-confidence predictions not possible with the other tools. Specifically, we have experimentally validated predictions of previously unknown phosphorylations by the LATS1, AKT1, PKA and MST2 kinases in human. Thus, our tool is useful for focusing phosphoproteomic experiments, and facilitates the discovery of new phosphorylation reactions. Our model can be accessed publicly via an easy-to-use web interface (LinkPhinder)

Precision Astrometry with the Very Long Baseline Array: Parallaxes and Proper Motions for 14 Pulsars

Astrometry can bring powerful constraints to bear on a variety of scientific questions about neutron stars, including their origins, astrophysics, evolution, and environments. Using phase-referenced observations at the VLBA, in conjunction with pulsar gating and in-beam calibration, we have measured the parallaxes and proper motions for 14 pulsars. The smallest measured parallax in our sample is 0.13+-0.02 mas for PSR B1541+09, which has a most probable distance of 7.2+1.3-1.1 kpc. We detail our methods, including initial VLA surveys to select candidates and find in-beam calibrators, VLBA phase-referencing, pulsar gating, calibration, and data reduction. The use of the bootstrap method to estimate astrometric uncertainties in the presence of unmodeled systematic errors is also described. Based on our new model-independent estimates for distance and transverse velocity, we investigate the kinematics and birth sites of the pulsars and revisit models of the Galactic electron density distribution. We find that young pulsars are moving away from the Galactic plane, as expected, and that age estimates from kinematics and pulsar spindown are generally in agreement, with certain notable exceptions. Given its present trajectory, the pulsar B2045-16 was plausibly born in the open cluster NGC 6604. For several high-latitude pulsars, the NE2001 electron density model underestimates the parallax distances by a factor of two, while in others the estimates agree with or are larger than the parallax distances, suggesting that the interstellar medium is irregular on relevant length scales. The VLBA astrometric results for the recycled pulsar J1713+0747 are consistent with two independent estimates from pulse timing, enabling a consistency check between the different reference frames.Comment: 16 pages, 9 figures, 4 tables; results unchanged; revised version accepted by Ap

Ceftiofur Resistance in Salmonella enterica Serovar Heidelberg from Chicken Meat and Humans, Canada

Use of this drug in chickens may limit effectiveness of cephalosporins in treating human infections

Astrometry and geodesy with radio interferometry: experiments, models, results

Summarizes current status of radio interferometry at radio frequencies between Earth-based receivers, for astrometric and geodetic applications. Emphasizes theoretical models of VLBI observables that are required to extract results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the achievements of VLBI during the past two decades in reference frames, Earth orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys., Vol. 70, Oct. 199

The long and the short of it: Mechanisms of synchronous and compensatory dynamics across temporal scales

Synchronous dynamics (fluctuations that occur in unison) are universal phenomena with widespread implications for ecological stability. Synchronous dynamics can amplify the destabilizing effect of environmental variability on ecosystem functions such as productivity, whereas the inverse, compensatory dynamics, can stabilize function. Here we combine simulation and empirical analyses to elucidate mechanisms that underlie patterns of synchronous versus compensatory dynamics. In both simulated and empirical communities, we show that synchronous and compensatory dynamics are not mutually exclusive but instead can vary by timescale. Our simulations identify multiple mechanisms that can generate timescale-specific patterns, including different environmental drivers, diverse life histories, dispersal, and non-stationary dynamics. We find that traditional metrics for quantifying synchronous dynamics are often biased toward long-term drivers and may miss the importance of short-term drivers. Our findings indicate key mechanisms to consider when assessing synchronous versus compensatory dynamics and our approach provides a pathway for disentangling these dynamics in natural systems