Reconstructing Positions \& Peculiar Velocities of Galaxy Clusters within 25000 km/sec: The Bulk Velocity

Using a dynamical 3-D reconstruction procedure we estimate the peculiar velocities of $R\ge0$ Abell/ACO galaxy clusters from their measured redshift within 25000 km/sec. The reconstruction algorithm relies on the linear gravitational instability hypothesis, assumes linear biasing and requires an input value of the cluster $\beta$-parameter ($\beta_c \equiv \Omega_{\circ}^{0.6}/b_c$), which we estimated in Branchini \& Plionis (1995) to be $\beta_c\simeq 0.21$. The resulting cluster velocity field is dominated by a large scale streaming motion along the Perseus Pisces--Great Attractor base-line directed towards the Shapley concentration, in qualitative agreement with the galaxy velocity field on smaller scales. Fitting the predicted cluster peculiar velocities to a dipole term, in the local group frame and within a distance of $\sim 18000$ km/sec, we recover extremely well both the local group velocity and direction, in disagreement with the Lauer \& Postman (1994) observation. However, we find a $\sim 6\%$ probability that their observed velocity field could be a realization of our corresponding one, if the latter is convolved with their large distance dependent errors. Our predicted cluster bulk velocity amplitude agrees well with that deduced by the POTENT and the da Costa et al. (1995) analyses of observed galaxy motions at $\sim 5000 - 6000$ km/sec; it decreases thereafter while at the Lauer \& Postman limiting depth ($\sim 15000$ km/sec) its amplitude is $\sim 150$ km/sec, in comfortable agreement with most cosmological models.Comment: 8 pages, uuencoded compressed tarred postscript file uncluding text and 3 figures. Accepted in ApJ Letter

El uso de señales para la atención en el arte Griego antiguo: aspectos que influencian la concentración en la obra de arte y sus elementos

The goal of this study is to identify cues for the cognitive process of attention in ancient Greek art, aiming to find confirmation of its possible use by ancient Greek audiences and artists. Evidence of cues that trigger attention’s psychological dispositions was searched through content analysis of image reproductions of ancient Greek sculpture and fine vase painting from the archaic to the Hellenistic period - ca. 7th -1st cent. BC. Through this analysis, it was possible to observe the presence of cues that trigger orientation to the work of art (i.e. amplification, contrast, emotional salience, simplification, symmetry), of a cue that triggers a disseminate attention to the parts of the work (i.e. distribution of elements) and of cues that activate selective attention to specific elements in the work of art (i.e. contrast of elements, salient color, central positioning of elements, composition regarding the flow of elements and significant objects). Results support the universality of those dispositions, probably connected with basic competencies that are hard-wired in the nervous system and in the cognitive processes.El objetivo de este estudio es identificar las señales para el proceso cognitivo de la atención en el arte Griego antiguo, con la intención de detectar su posible uso por los antiguos griegos (público y artistas). La evidencia de señales que desencadenan las disposiciones psicológicas de la atención se buscó mediante el análisis de contenido de reproducciones de imágenes de arte Griego antiguo (escultura y pintura de vasos desde el período arcaico hasta el período Helenístico – ca. 7º-1º siglo AC). Por medio de este análisis fue posible observar la presencia de señales que condicionan la orientación para la obra de arte (i.e. amplificación, contraste, énfasis emocional, simplificación, simetría), de una señal que provoca una atención diseminada a las partes de la obra (i.e. distribución de los elementos) y de señales que activan una atención selectiva a las partes de la obra (i.e. contraste de los elementos, color saliente, posicionamiento central de los elementos, composición con respecto al fluir de los elementos y objetos significativos). Los resultados apoyan la universalidad de esas disposiciones, probablemente relacionado con competencias básicas del sistema nervioso y de los procesos cognitivos

Numerical and Experimental Investigation of Pressure Losses at Suction of a Twin Screw Compressor

Rotary twin screw machines are used in the wide range of industrial applications and are capable of handling single and multiphase fluids as compressors, expanders and pumps. Concentration of liquid in the inlet flow can influence the performance of the machine significantly. Characteristics of the multiphase flow at the suction of a screw compressor depend on the local flow velocities and concentration. Local flow velocity measurements inside the screw compressors are difficult to obtain. However other flow properties such as local pressures are easier to attain. It is therefore useful to carry out experiments with local pressure variations in the suction which can be used to validate the 3D numerical Computational Fluid Dynamic (CFD) models that could help in studying the single and multiphase flow behaviour in screw compressors. This paper presents experimental efforts to measure the local pressure losses inside the suction plenum of the screw compressor. Pressure variations are measured at 23 locations in the suction port at various operating conditions and compared with 3D CFD model. The grid generator SCORGTM was used for generating numerical mesh of rotors. The flow calculations were carried out using commercial 3D solver ANSYS CFX. It was found that the local pressure changes predicted by the CFD model are in the good agreement with measured pressures. This validated the use of CFD for modelling of the single phase flows in suction of screw machines

Semantic Integration of Cervical Cancer Data Repositories to Facilitate Multicenter Association Studies: The ASSIST Approach

The current work addresses the unifi cation of Electronic Health Records related to cervical cancer into a single medical knowledge source, in the context of the EU-funded ASSIST research project. The project aims to facilitate the research for cervical precancer and cancer through a system that virtually unifi es multiple patient record repositories, physically located in different medical centers/hospitals, thus, increasing fl exibility by allowing the formation of study groups “on demand” and by recycling patient records in new studies. To this end, ASSIST uses semantic technologies to translate all medical entities (such as patient examination results, history, habits, genetic profi le) and represent them in a common form, encoded in the ASSIST Cervical Cancer Ontology. The current paper presents the knowledge elicitation approach followed, towards the defi nition and representation of the disease’s medical concepts and rules that constitute the basis for the ASSIST Cervical Cancer Ontology. The proposed approach constitutes a paradigm for semantic integration of heterogeneous clinical data that may be applicable to other biomedical application domains

Effects of Culture on Preferred Individual Learning Systems: Consequences for Knowledge Management System Use

Global enterprises increasingly deploy Knowledge Management Systems (KMSs) to raise productivity and remain competitive. KMSs, by prescribing ways of capturing and disseminating information, mediate the learning processes in organizations. Because of this mediating effect, individuals from distinct national cultures may react differently to KMSs. This research examines how cultural characteristics (e.g., those identified by Hofstede, Trompenaars, and Hall and Hall) may be related to the individual use of KMSs for learning. The first phase of the study examines individual cultural characteristics and learning preferences (degree of structure and extent of direct social interactions). The second phase examines the relationships between cultural measures and actual KMS use

Evaluating Conjunctive Triple Pattern Queries over Large Structured Overlay Networks

We study the problem of evaluating conjunctive queries com- posed of triple patterns over RDF data stored in distributed hash tables. Our goal is to develop algorithms that scale to large amounts of RDF data, distribute the query processing load evenly and incur little network traffic. We present and evaluate two novel query processing algorithms with these possibly conflicting goals in mind. We discuss the various tradeoffs that occur in our setting through a detailed experimental eval- uation of the proposed algorithms

Magnetic Energy and Helicity Budgets in the Active-Region Solar Corona. I. Linear Force-Free Approximation

We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general expression that gives results practically equivalent to those of the magnetic Virial theorem. All magnetic energy and helicity budgets are formulated in terms of surface integrals applied to the lower boundary, thus avoiding computationally intensive three-dimensional magnetic field extrapolations. We analytically and numerically connect our derivations with classical expressions for the magnetic energy and helicity, thus presenting a so-far lacking unified treatment of the energy/helicity budgets in the constant-alpha approximation. Applying our derivations to photospheric vector magnetograms of an eruptive and a noneruptive solar active regions, we find that the most profound quantitative difference between these regions lies in the estimated free magnetic energy and relative magnetic helicity budgets. If this result is verified with a large number of active regions, it will advance our understanding of solar eruptive phenomena. We also find that the constant-alpha approximation gives rise to large uncertainties in the calculation of the free magnetic energy and the relative magnetic helicity. Therefore, care must be exercised when this approximation is applied to photospheric magnetic field observations. Despite its shortcomings, the constant-alpha approximation is adopted here because this study will form the basis of a comprehensive nonlinear force-free description of the energetics and helicity in the active-region solar corona, which is our ultimate objective.Comment: 44 pages, 8 figures, 2 tables. The Astrophysical Journal, in pres

A 3-Dimensional study of the Local Environment of Bright IRAS Galaxies: The AGN/Starburst connection

We present a 3-dimensional study of the local ($\leq 100 h^{-1}$ kpc) and the large scale ($\leq$ 1 $h^{-1}$ Mpc) environment of Bright IRAS Galaxies (BIRGs). For this purpose we use 87 BIRGs located at high galactic latitudes (with 0.008$\leq z \leq$0.018) as well as a control sample of non-active galaxies having the same morphological, redshift and diameter size distributions as the corresponding BIRG sample. Using the Center for Astrophysics (CfA2) and Southern Sky Redshift Survey (SSRS) galaxy catalogues ($m_b\lesssim 15.5$)as well as our own spectroscopic observations ($m_b\lesssim19.0$) for a subsample of the original BIRG sample, we find that the fraction of BIRGs with a close neighbor is significantly higher than that of their control sample. Comparing with a related analysis of Sy1 and Sy2 galaxies of Koulouridis et al. (2006) we find that BIRGs have a similar environment as Sy2s, although the fraction of BIRGs with a bright close neighbor is even higher than that of Sy2 galaxies. An additional analysis of the relation between FIR colors and the type of activity of each BIRG shows a significant difference between the colors of strongly-interacting and non-interacting starbursts and a resemblance between the colors of non-interacting starbursts and Sy2s. Our results support the view where close interactions can drive molecular clouds towards the galactic center, triggering starburst activity and obscuring the nuclear activity. When the close neighbor moves away, starburst activity is reduced with the simultaneous appearance of an obscured (type 2) AGN. Finally, the complete disentanglement of the pair gives birth to an unobscured (type 1) AGN.Comment: Accepted for publication in The Astrophysical Journal,10 pages, 4 figure

Cyclooxygenase-2 Expression in Bladder Cancer and Patient Prognosis: Results from a Large Clinical Cohort and Meta-Analysis

Aberrant overexpression of cyclooxygenase-2 (COX2) is observed in urothelial carcinoma of the bladder (UCB). Studies evaluating COX2 as a prognostic marker in UCB report contradictory results. We determined the prognostic potential of COX2 expression in UCB and quantitatively summarize the results with those of the literature through a meta-analysis. Newly diagnosed UCB patients recruited between 1998–2001 in 18 Spanish hospitals were prospectively included in the study and followed-up (median, 70.7 months). Diagnostic slides were reviewed and uniformly classified by expert pathologists. Clinical data was retrieved from hospital charts. Tissue microarrays containing non-muscle invasive (n = 557) and muscle invasive (n = 216) tumours were analyzed by immunohistochemistry using quantitative image analysis. Expression was evaluated in Cox regression models to assess the risk of recurrence, progression and disease-specific mortality. Meta-hazard ratios were estimated using our results and those from 11 additional evaluable studies. COX2 expression was observed in 38% (211/557) of non-muscle invasive and 63% (137/216) of muscle invasive tumors. Expression was associated with advanced pathological stage and grade (p<0.0001). In the univariable analyses, COX2 expression - as a categorical variable - was not associated with any of the outcomes analyzed. As a continuous variable, a weak association with recurrence in non-muscle invasive tumors was observed (p-value = 0.048). In the multivariable analyses, COX2 expression did not independently predict any of the considered outcomes. The meta-analysis confirmed these results. We did not find evidence that COX2 expression is an independent prognostic marker of recurrence, progression or survival in patients with UCB.The work was partially supported by the Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, Ministry of Science and Innovation, Spain (G03/174, 00/0745, PI051436, PI061614 and G03/174); Red Temática de Investigación Cooperativa en Cáncer- RD06/0020-RTICC; Consolider ONCOBIO; EU-FP6-STREP-37739-DRoP-ToP; EU-FP7-HEALTH-F2-2008-201663-UROMOL; EU-FP7-HEALTH-F2-2008-201333-DECanBio; USA-NIH-RO1-CA089715; and a PhD fellowship awarded to MJC from the ‘‘la Caixa’’ foundation, Spain, and a postdoctoral fellowship awarded to AFSA from the Fundación Científica de la AEC

Dioxin Revisited: Developments Since the 1997 IARC Classification of Dioxin as a Human Carcinogen

In 1997 the International Agency for Research on Cancer (IARC) classified 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD; the most potent dioxin congener) as a group 1 carcinogen based on limited evidence in humans, sufficient evidence in experimental animals, and extensive mechanistic information indicating that TCDD acts through a mechanism involving the aryl hydrocarbon receptor (AhR), which is present in both humans and animals. The judgment of limited evidence in humans was based primarily on an elevation of all cancers combined in four industrial cohorts. The group 1 classification has been somewhat controversial and has been challenged in the literature in recent years. In this article we review the epidemiologic and mechanistic evidence that has emerged since 1997. New epidemiologic evidence consists primarily of positive exposure–response analyses in several of the industrial cohorts, as well as evidence of excesses of several specific cancers in the Seveso accident cohort. There are also new data regarding how the AhR functions in mediating the carcinogenic response to TCDD. The new evidence generally supports the 1997 IARC classification