253 research outputs found

    Advancements in Laparoscopic Partial Nephrectomy: Expanding the Feasibility of Nephron-Sparing

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    Partial nephrectomy (PN) offers equivalent oncologic outcomes to radical nephrectomy (RN) but has greater preservation of renal function and less risk of chronic kidney disease and cardiovascular disease. Laparoscopic PN remains underutilized likely because it is a technically challenging operation with higher rates of perioperative complications compared to open PN and laparoscopic RN. A review of the latest PN literature demonstrates that recent advancements in laparoscopic approaches, imaging modalities, ischemic mitigating strategies, renorrhaphy techniques, and hemostatic agents will likely allow greater utilization of LPN and expand its usage to increasingly more complex tumors

    Prostate Stromal Tumor of Uncertain Malignant Potential: Case Report With 5-Year Follow-up

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    AbstractProstate stromal tumor of uncertain malignant potential is a term used to describe a specialized proliferation of stromal cells within the prostate. Most of these tumors tend to be benign, but some can present with local invasion or progress to prostatic stromal sarcoma with distant metastasis. We report a case of a 62-year-old male patient who presented to us with a diagnosis of stromal tumor of uncertain malignant potential. We have followed up the patient for 5 years with imaging, prostate-specific antigen checks, and annual prostate biopsies

    Measuring Redshift-Space Distortions using Photometric Surveys

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    We outline how redshift-space distortions (RSD) can be measured from the angular correlation function w({\theta}), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by comparing results from bins with top-hat galaxy selection in redshift, and bins based on the radial position of galaxy pair centres. This comparison can also be used to test the accuracy of the photometric redshifts. The presence of RSD will be clearly detectable with the next generation of photometric redshift surveys. We show that the Dark Energy Survey (DES) will be able to measure f(z){\sigma}_8(z) to a 1{\sigma} accuracy of (17 {\times} b)%, using galaxies drawn from a single narrow redshift slice centered at z = 1. Here b is the linear bias, and f is the logarithmic rate of change of the linear growth rate with respect to the scale factor. Extending to measurements of w({\theta}) for a series of bins of width 0.02(1 + z) over 0.5 < z < 1.4 will measure {\gamma} to a 1{\sigma} accuracy of 25%, given the model f = {\Omega}_m(z)^{\gamma}, and assuming a linear bias model that evolves such that b = 0.5 + z (and fixing other cosmological parameters). The accuracy of our analytic predictions is confirmed using mock catalogs drawn from simulations conducted by the MICE collaboration.Comment: Accepted by MNRAS, revisions include fixing of typos and clarification of the tex

    Expression of the SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1 (SERK1) gene is associated with developmental change in the life cycle of the model legume Medicago truncatula

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    SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) genes have been demonstrated to play a role in somatic embryogenesis in several plant species. As more is learnt about these genes, the view of their role in plant development has broadened. The Medicago truncatula MtSERK1 gene has been associated with somatic embryogenesis and in vitro root formation. In order to study the role of MtSERK1 in development further, the MtSERK1 promoter sequence has been isolated and cloned into a promoter–GUS analysis vector. SERK1 promoter-driven GUS expression was studied in A. tumefaciens-transformed cultures and regenerated plants, in A. rhizogenes-transformed root clones, and in nodulation. In embryogenic cultures, GUS staining is detected after 2 d of culture at the edge of the explant and around vascular tissue. Expression at the explant edge intensifies over subsequent days and then is lost from the edge as callus formation moves inward. MtSERK1 expression appears to be associated with new callus formation. When somatic embryos form, GUS staining occurs throughout embryo development. Zygotic embryos show expression until the heart stage. The in planta studies reveal a number of interesting expression patterns. There appear to be three types. (i) Expression associated with the primary meristems of the root and shoot and the newly formed meristems of the lateral roots and nodule. (ii) Expression at the junction between one type of tissue or organ and another. (iii) Expression associated with the vascular tissue procambial cells. The data led us to conclude that MtSERK1 expression is associated with developmental change, possibly reflecting cellular reprogramming

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measuring structure growth using passive galaxies

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    We explore the benefits of using a passively evolving population of galaxies to measure the evolution of the rate of structure growth between z=0.25 and z=0.65 by combining data from the SDSS-I/II and SDSS-III surveys. The large-scale linear bias of a population of dynamically passive galaxies, which we select from both surveys, is easily modeled. Knowing the bias evolution breaks degeneracies inherent to other methodologies, and decreases the uncertainty in measurements of the rate of structure growth and the normalization of the galaxy power-spectrum by up to a factor of two. If we translate our measurements into a constraint on sigma_8(z=0) assuming a concordance cosmological model and General Relativity (GR), we find that using a bias model improves our uncertainty by a factor of nearly 1.5. Our results are consistent with a flat Lambda Cold Dark Matter model and with GR.Comment: Accepted for publication in MNRAS (clarifications added, results and conclusions unchanged

    The power spectrum from the angular distribution of galaxies in the CFHTLS-Wide fields at redshift ~0.7

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    We measure the real-space galaxy power spectrum on large scales at redshifts 0.5 to 1.2 using optical colour-selected samples from the CFHT Legacy Survey. With the redshift distributions measured with a preliminary ~14000 spectroscopic redshifts from the VIMOS Public Extragalactic Redshift Survey (VIPERS), we deproject the angular distribution and directly estimate the three-dimensional power spectrum. We use a maximum likelihood estimator that is optimal for a Gaussian random field giving well-defined window functions and error estimates. This measurement presents an initial look at the large-scale structure field probed by the VIPERS survey. We measure the galaxy bias of the VIPERS-like sample to be b_g=1.38 +- 0.05 (sigma_8=0.8) on scales k<0.2h/mpc averaged over 0.5<z<1.2. We further investigate three photometric redshift slices, and marginalising over the bias factors while keeping other LCDM parameters fixed, we find the matter density Omega_m=0.30+-0.06.Comment: Minor changes to match journal versio

    Interpreting large-scale redshift-space distortion measurements

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    The simplest theory describing large-scale redshift-space distortions (RSD), based on linear theory and distant galaxies, depends on the growth of cosmological structure, suggesting that strong tests of General Relativity can be constructed from galaxy surveys. As data sets become larger and the expected constraints more precise, the extent to which the RSD follow the simple theory needs to be assessed in order that we do not introduce systematic errors into the tests by introducing inaccurate simplifying assumptions. We study the impact of the sample geometry, non-linear processes, and biases induced by our lack of understanding of the radial galaxy distribution on RSD measurements. Using LasDamas simulations of the Sloan Digital Sky Survey II (SDSS-II) Luminous Red Galaxy (LRG) data, these effects are shown to be important at the level of 20 per cent. Including them, we can accurately model the recovered clustering in these mock catalogues on scales 30 -- 200 Mpc/h. Applying this analysis to robustly measure parameters describing the growth history of the Universe from the SDSS-II data, gives f(z=0.25)σ8(z=0.25)=0.3512±0.0583f(z=0.25)\sigma_8(z=0.25)=0.3512\pm0.0583 and f(z=0.37)σ8(z=0.37)=0.4602±0.0378f(z=0.37)\sigma_8(z=0.37)=0.4602\pm0.0378 when no prior is imposed on the growth-rate, and the background geometry is assumed to follow a Λ\LambdaCDM model with the WMAP + SNIa priors. The standard WMAP constrained Λ\LambdaCDM model with General Relativity predicts f(z=0.25)σ8(z=0.25)=0.4260±0.0141f(z=0.25)\sigma_8(z=0.25)=0.4260\pm0.0141 and f(z=0.37)σ8(z=0.37)=0.4367±0.0136f(z=0.37)\sigma_8(z=0.37)=0.4367\pm0.0136, which is fully consistent with these measurements.Comment: 20 pages, 17 figures, 1 tabl

    The Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected via the Sunyaev-Zel'dovich Effect

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    We present optical and X-ray properties for the first confirmed galaxy cluster sample selected by the Sunyaev-Zel'dovich Effect from 148 GHz maps over 455 square degrees of sky made with the Atacama Cosmology Telescope. These maps, coupled with multi-band imaging on 4-meter-class optical telescopes, have yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066. Of these 23 clusters, 10 are newly discovered. The selection of this sample is approximately mass limited and essentially independent of redshift. We provide optical positions, images, redshifts and X-ray fluxes and luminosities for the full sample, and X-ray temperatures of an important subset. The mass limit of the full sample is around 8e14 Msun, with a number distribution that peaks around a redshift of 0.4. For the 10 highest significance SZE-selected cluster candidates, all of which are optically confirmed, the mass threshold is 1e15 Msun and the redshift range is 0.167 to 1.066. Archival observations from Chandra, XMM-Newton, and ROSAT provide X-ray luminosities and temperatures that are broadly consistent with this mass threshold. Our optical follow-up procedure also allowed us to assess the purity of the ACT cluster sample. Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported sample represents one of the largest SZE-selected sample of massive clusters over all redshifts within a cosmologically-significant survey volume, which will enable cosmological studies as well as future studies on the evolution, morphology, and stellar populations in the most massive clusters in the Universe.Comment: 20 pages, 15 figures, 6 tables. Accepted for publication in ApJ. Higher resolution figures available at: http://peumo.rutgers.edu/~felipe/e-prints

    THE ROLE OF INTERDEPENDENCE IN THE MICRO-FOUNDATIONS OF ORGANIZATION DESIGN: TASK, GOAL, AND KNOWLEDGE INTERDEPENDENCE

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    Interdependence is a core concept in organization design, yet one that has remained consistently understudied. Current notions of interdependence remain rooted in seminal works, produced at a time when managers’ near-perfect understanding of the task at hand drove the organization design process. In this context, task interdependence was rightly assumed to be exogenously determined by characteristics of the work and the technology. We no longer live in that world, yet our view of interdependence has remained exceedingly task-centric and our treatment of interdependence overly deterministic. As organizations face increasingly unpredictable workstreams and workers co-design the organization alongside managers, our field requires a more comprehensive toolbox that incorporates aspects of agent-based interdependence. In this paper, we synthesize research in organization design, organizational behavior, and other related literatures to examine three types of interdependence that characterize organizations’ workflows: task, goal, and knowledge interdependence. We offer clear definitions for each construct, analyze how each arises endogenously in the design process, explore their interrelations, and pose questions to guide future research
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