930 research outputs found

    Top-down structures of mafic enclaves within the Valle Fértil magmatic complex (Early Ordovician, San Juan, Argentina)

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    Magmatic structures related to the mechanical interaction between mafic magmas and granitoids have been studied in the Valle Fértil calc-alkaline igneous complex, Argentina. Excepcional outcrops with vertical walls of more than 300 m high allow us the study of three-dimensional geometries of individual blobs of mafic magma as well as the geometry of pipe-like structures in which mafic microgranular enclaves are concentrated in more than 50 times the normal abundance in the granodiorite mass. The shape of enclaves and pipe-like structures are interpreted as the ressult of top-to-down intrusions of a mafic magma into a granodiorite-tonalite mass. These sinking structures are the result of a reverselly stratified magma chamber with gabbros and diorites at the top and granodiorite-tonalite at the bottom. They may account for most of the structures found in microgranular enclaves and magma mingling zones that characterize calc-alkaline batholiths. Synplutonic intrusions from the top is the only plausible mechanism to account for the observed structures. The model may be of general application to calc-alkaline batholiths characterized by the presence of mafic microgranular enclaves. An implication of these reverselly stratified magma chambers is the presence of a petrological inversion which may be the consequence of cold diapirs emplaced below the mantle wedge in a suprasubduction setting

    Integral Transforms for Conformal Field Theories with a Boundary

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    A new method is developed for solving the conformally invariant integrals that arise in conformal field theories with a boundary. The presence of a boundary makes previous techniques for theories without a boundary less suitable. The method makes essential use of an invertible integral transform, related to the radon transform, involving integration over planes parallel to the boundary. For successful application of this method several nontrivial hypergeometric function relations are also derived.Comment: 20 pagess, LateX fil

    On the AdS Higher Spin / O(N) Vector Model Correspondence: degeneracy of the holographic image

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    We explore the conjectured duality between the critical O(N) vector model and minimal bosonic massless higher spin (HS) theory in AdS. In the boundary free theory, the conformal partial wave expansion (CPWE) of the four-point function of the scalar singlet bilinear is reorganized to make it explicitly crossing-symmetric and closed in the singlet sector, dual to the bulk HS gauge fields. We are able to analytically establish the factorized form of the fusion coefficients as well as the two-point function coefficient of the HS currents. We insist in directly computing the free correlators from bulk graphs with the unconventional branch. The three-point function of the scalar bilinear turns out to be an "extremal" one at d=3. The four-leg bulk exchange graph can be precisely related to the CPWs of the boundary dual scalar and its shadow. The flow in the IR by Legendre transforming at leading 1/N, following the pattern of double-trace deformations, and the assumption of degeneracy of the hologram lead to the CPWE of the scalar four-point function at IR. Here we confirm some previous results, obtained from more involved computations of skeleton graphs, as well as extend some of them from d=3 to generic dimension 2<d<4.Comment: 22 pages, 5 figure

    RELATIONSHIP AMONG SYMPTOMS SCORE,PROSTATE VOLUME AND URINARY FLOW RATES IN 543 PATIENTS WITH AND WIHTOUT BPH

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    BACKGROUND. Studies on the relationship among symptom score, urinary flow rate, and prostate volume in men with lower urinary tract symptoms (LUTS) continue to be of great interest. METHODS. A total of 2,418 men, aged 30-86 years, agreed to participate in an interview and to complete a questionnaire regarding voiding patterns. All subjects answering positively to one or more of the questions were submitted to a diagnostic assessment, based on the algorithm outlined by the guidelines of the International Consultation on Benign Prostatic Hyperplasia (BPH). Five hundred forty-three out of the 2,418 participants (22.45%) were evaluated. At the end of the diagnostic evaluation, 400 men with LUTS but without concomitant conditions (except BPH) known to interfere with normal voiding were selected. Descriptive statistics were used to characterize age, symptom score (International Prostate Symptom Score), prostate volume, and urinary flow rate distribution in these patients. Correlations among the aforementioned parameters were evaluated by means of a multivariate, multiple linear regression and logistic regression model. RESULTS. As reported in other studies, only weak or modest correlations were found. Moreover, the 400 cases were classified according to four age decades. The decrease in peak and mean flow rate per decade of age was similar (0.5 and 0.4 ml/sec); the increase in prostate volume and in total symptom score per decade was 3.3 cc and 0.6, respectively. In patients less than 50 years old, most of the correlations were stronger than those observed in the entire population of 400 men (age and prostate volume, c.c. 0.2864; age and peak flow rate, c.c. -0.2689; age and mean flow rate, c.c. -0.3034). However, symptom score continued to be weakly correlated with age and prostate volume (c.c. 0.0498 and 0.1966, respectively). In the last part of the study, men were assigned to different treatment strategies. Patients who were assigned to surgical treatment had higher prostate volume and IPSS and lower urinary flow rate than those assigned to nonsurgical treatment. CONCLUSIONS. We believe that the reason for the weak statistical association frequently reported in the literature is mainly the urology clinic-based population from which the patient samples were drawn. Data emerging from this analysis support the hypothesis that age is one of the principal factors influencing the relationship among symptom score, urinary flow rate, and prostate volume. (C) 1998 Wiley-Liss, Inc

    Affleck-Dine dynamics and the dark sector of pangenesis

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    Pangenesis is the mechanism for jointly producing the visible and dark matter asymmetries via Affleck-Dine dynamics in a baryon-symmetric universe. The baryon-symmetric feature means that the dark asymmetry cancels the visible baryon asymmetry and thus enforces a tight relationship between the visible and dark matter number densities. The purpose of this paper is to analyse the general dynamics of this scenario in more detail and to construct specific models. After reviewing the simple symmetry structure that underpins all baryon-symmetric models, we turn to a detailed analysis of the required Affleck-Dine dynamics. Both gravity-mediated and gauge-mediated supersymmetry breaking are considered, with the messenger scale left arbitrary in the latter, and the viable regions of parameter space are determined. In the gauge-mediated case where gravitinos are light and stable, the regime where they constitute a small fraction of the dark matter density is identified. We discuss the formation of Q-balls, and delineate various regimes in the parameter space of the Affleck-Dine potential with respect to their stability or lifetime and their decay modes. We outline the regions in which Q-ball formation and decay is consistent with successful pangenesis. Examples of viable dark sectors are presented, and constraints are derived from big bang nucleosynthesis, large scale structure formation and the Bullet cluster. Collider signatures and implications for direct dark matter detection experiments are briefly discussed. The following would constitute evidence for pangenesis: supersymmetry, GeV-scale dark matter mass(es) and a Z' boson with a significant invisible width into the dark sector.Comment: 51 pages, 7 figures; v2: minor modifications, comments and references added; v3: minor changes, matches published versio

    Effect of bone proteins on human prostate cancer cell lines in vitro

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    BACKGROUND Despite the high incidence and serious consequences of skeletal metastasis in prostate cancer patients, the mechanisms involved in establishing secondary lesions in bone are not well-understood. In this study, the role of the mineralized bone matrix in the process of skeletal metastasis was evaluated. METHODS Attachment, migration, and proliferation responses of human prostate cancer cells to a crude bone protein extract (CBE) were studied. LNCaP and DU145 cells were utilized in 24-hr attachment assays. Boyden chamber chemotactic assays and cell proliferation assays utilized DU145 cells. RESULTS CBE and fibronectin (FN) promoted attachment of DU145 cells, whereas only FN facilitated attachment of LNCaP cells. CBE-mediated adhesion of DU145 cells was reduced by 94% with cycloheximide, by 98% with RGD peptides, and by 94% with an antibody to ΑvΒ3. Although DU145 cells migrated toward FN, CBE did not promote migration of DU145 cells. DU145 cells grown in the presence of CBE-containing media demonstrated a significant reduction in cell number by day 4. The antiproliferative effect of CBE was not due to cell toxicity. CONCLUSIONS In conclusion, results from this study indicate that mineralized bone proteins promote the attachment of DU145 cells in vitro and suggest that bone proteins may play a key role in vivo during the development of metastatic prostate lesions in bone. Prostate 36:14–22, 1998. © 1998 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34753/1/3_ftp.pd

    The Palaeocene Cerro Munro tonalite intrusion (Chubut Province, Argentina): A plutonic remnant of explosive volcanism?

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    The Cerro Munro sub-volcanic intrusion is emplaced in the back-arc (400 km from the trench) as small sub-circular tonalite-granodiorite plutons with abundant radial porphyritic dikes. U-Pb zircon SHRIMP data give an age of crystallization of 57 Ma ± 1.4 Ma. It is located to the east of the North Patagonian Batholith (NPB) that shows a protracted and episodic magmatic history from Cretaceous to Miocene time. The NPB Palaeogene episode is characterized by the lack of magmatic activity at the arc axis, as small plutonic emplacements move to the fore-arc and back-arc. This Palaeogene tectono-magmatic episode is ruled by the detachment of the Aluk plate during the Aluk-Farallon-SAM triple junction, active at that time along northern Patagonia active margin, changing the Cretaceous ?NPB orogenic? setting to a Palaeogene ?Munro transitional? tectono-magmatic setting. Near the contacts, the tonalite contains abundant enclaves of igneous appearance and variable size from several cm to dm, described as autoliths. The study of autoliths and host tonalite reveals interesting results on the processes of fractionation in a thermally zoned magma chamber. Autoliths, and in a large extent the host tonalite, represent disguised cumulates from which a hydrous silicic liquid was extracted. Barometry calculations from mineral chemistry in both autoliths and tonalites record a shallow pressure of emplacement of 0.5 kbar. Rhyolite-dacite flows and ignimbrites, surrounding the northern contact of the Cerro Munro tonalite, may represent the exsolved liquid from the plutonic cumulates. The study by cathodoluminiscence and electron backscattered diffraction techniques from a rhyolite-hosted quartz supports this protracted history of the Cerro Munro magma chamber.Facultad de Ciencias Naturales y MuseoCentro de Investigaciones GeológicasConsejo Nacional de Investigaciones Científicas y Técnica

    The Palaeocene Cerro Munro tonalite intrusion (Chubut Province, Argentina): A plutonic remnant of explosive volcanism?

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    The Cerro Munro sub-volcanic intrusion is emplaced in the back-arc (400 km from the trench) as small sub-circular tonalite-granodiorite plutons with abundant radial porphyritic dikes. U-Pb zircon SHRIMP data give an age of crystallization of 57 Ma ± 1.4 Ma. It is located to the east of the North Patagonian Batholith (NPB) that shows a protracted and episodic magmatic history from Cretaceous to Miocene time. The NPB Palaeogene episode is characterized by the lack of magmatic activity at the arc axis, as small plutonic emplacements move to the fore-arc and back-arc. This Palaeogene tectono-magmatic episode is ruled by the detachment of the Aluk plate during the Aluk-Farallon-SAM triple junction, active at that time along northern Patagonia active margin, changing the Cretaceous ?NPB orogenic? setting to a Palaeogene ?Munro transitional? tectono-magmatic setting. Near the contacts, the tonalite contains abundant enclaves of igneous appearance and variable size from several cm to dm, described as autoliths. The study of autoliths and host tonalite reveals interesting results on the processes of fractionation in a thermally zoned magma chamber. Autoliths, and in a large extent the host tonalite, represent disguised cumulates from which a hydrous silicic liquid was extracted. Barometry calculations from mineral chemistry in both autoliths and tonalites record a shallow pressure of emplacement of 0.5 kbar. Rhyolite-dacite flows and ignimbrites, surrounding the northern contact of the Cerro Munro tonalite, may represent the exsolved liquid from the plutonic cumulates. The study by cathodoluminiscence and electron backscattered diffraction techniques from a rhyolite-hosted quartz supports this protracted history of the Cerro Munro magma chamber.Facultad de Ciencias Naturales y MuseoCentro de Investigaciones GeológicasConsejo Nacional de Investigaciones Científicas y Técnica

    Three-gluon vertex in arbitrary gauge and dimension

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    One-loop off-shell contributions to the three-gluon vertex are calculated, in arbitrary covariant gauge and in arbitrary space-time dimension, including quark-loop contributions (with massless quarks). It is shown how one can get the results for all on-shell limits of interest directly from the general off-shell expression. The corresponding general expressions for the one-loop ghost-gluon vertex are also obtained. They allow for a check of consistency with the Ward--Slavnov--Taylor identity.Comment: 41 pages, LaTex, plus 3 figures in separate file. Misprints (signs) in eqs.(4.26), (C.2), (C.4), (C.5) are corrected. To appear in Phys. Rev.
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