Node-node distance distribution for growing networks

We present the simulation of the time evolution of the distance matrix. The result is the node-node distance distribution for various kinds of networks. For the exponential trees, analytical formulas are derived for the moments of the distance distribution.Comment: presented during the 37-th Polish Physicists' Meeting, Gdansk, Poland, 15-19 Sep. 2003, 6 pages, 3 figure

Leak detection using cepstrum of cross-correlation of transient pressure wave signals

A new leak detection method is proposed here which is based on the cepstrum of the cross-correlation of the pressure signals from two transducers. Computational simulations of leaks with different properties, size, position and shape, in a straight pipe and a T-Junction network were studied. The proposed method was successful in estimating leakages and the pipeline features with a high precision. For the results with a straight pipe, this method is considerably more accurate than using the cross-correlation leak detection method or the cepstrum method alone. However, the results obtained by cepstrum and cepstrum of cross-correlation for the T-Junction case were quite accurate, while cepstrum alone showed a slightly better precision

GPs are from Mars, Administrators are from Venus: The Role of Misaligned Occupational Dispositions in Inhibiting Mandated Role Change

Research on mandated occupational role change focuses on jurisdictional conflict to explain change failure. Our study of the English National Health Service highlights the role of occupational dispositions in shaping how mandated role change is implemented by members of multiple occupational groups. We find that tension stemming from misaligned dispositions may emerge as members of different occupations interact during their role change implementation efforts. Depending on dispositional responses to tension, change may fail as members of the different occupations avoid interactions. This suggests that effective role change can be elusive even in the initial absence of conflicting occupational interests

The tidal tails of NGC 2298

We present an implementation of the matched-filter technique to detect tidal tails of globular clusters. The method was tested using SDSS data for the globular cluster Palomar 5 revealing its well known tidal tails. We also ran a simulation of a globular cluster with a tidal tail where we successfully recover the tails for a cluster at the same position and with the same characteristics of NGC 2298. Based on the simulation we estimate that the matched-filter increases the contrast of the tail relative to the background of stars by a factor of 2.5 for the case of NGC 2298. We also present the photometry of the globular cluster NGC 2298 using the MOSAIC2 camera installed on the CTIO 4m telescope. The photometry covers ~ 3deg2 reaching V ~ 23. A fit of a King profile to the radial density profile of NGC 2298 shows that this cluster has a tidal radius of 15.91' \pm 1.07' which is twice as in the literature. The application of the matched-filter to NGC 2298 reveals several extra-tidal structures, including a leading and trailing tail. We also find that NGC 2298 has extra-tidal structures stretching towards and against the Galactic disk, suggesting strong tidal interaction. Finally, we assess how the matched-filter performs when applied to a globular cluster with and without mass segregation taken into account. We find that disregarding the effects of mass segregation may significantly reduce the detection limit of the matched-filter.Comment: 11 pages, 9 figures, 1 table. Accepted for publication on MNRAS main journa

Human place and response learning: navigation strategy selection, pupil size and gaze behavior.

In this study, we examined the cognitive processes and ocular behavior associated with on-going navigation strategy choice using a route learning paradigm that distinguishes between three different wayfinding strategies: an allocentric place strategy, and the egocentric associative cue and beacon response strategies. Participants approached intersections of a known route from a variety of directions, and were asked to indicate the direction in which the original route continued. Their responses in a subset of these test trials allowed the assessment of strategy choice over the course of six experimental blocks. The behavioral data revealed an initial maladaptive bias for a beacon response strategy, with shifts in favor of the optimal configuration place strategy occurring over the course of the experiment. Response time analysis suggests that the configuration strategy relied on spatial transformations applied to a viewpoint-dependent spatial representation, rather than direct access to an allocentric representation. Furthermore, pupillary measures reflected the employment of place and response strategies throughout the experiment, with increasing use of the more cognitively demanding configuration strategy associated with increases in pupil dilation. During test trials in which known intersections were approached from different directions, visual attention was directed to the landmark encoded during learning as well as the intended movement direction. Interestingly, the encoded landmark did not differ between the three navigation strategies, which is discussed in the context of initial strategy choice and the parallel acquisition of place and response knowledge

Metabolic syndrome and psychiatric disorders : a population-based study

Objective: To identify the association of metabolic syndrome (MetS) and psychiatric disorders in young adults in southern Brazil. Methods: This population based cross-sectional study involved a total of 1,023 young adults between the ages of 21 and 32 years. Current episodes of psychiatric disorders were assessed using the Mini International Neuropsychiatric Interview – Plus version. MetS was evaluated using the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATP III). Results: Of the 1,023 participants, 24.3% were identified with MetS, 13.5% were diagnosed with anxiety disorders, 7.5% with current depression, 3.9% with bipolar disorders and 10.1% were at risk of suicide. MetS was associated with ethnicity (p = 0.022), excess weight (p o 0.001), current anxiety disorders (p o 0.001), current mood disorders (bipolar disorder in mood episode and current depression) (p o 0.001), and suicide risk (p o 0.001). Conclusions: MetS was associated with psychiatric disorders. Awareness of factors associated with MetS can help identify high-risk individuals and stimulate disease prevention and control programs, as well as lifestyle changes

The use of information theory in evolutionary biology

Information is a key concept in evolutionary biology. Information is stored in biological organism's genomes, and used to generate the organism as well as to maintain and control it. Information is also "that which evolves". When a population adapts to a local environment, information about this environment is fixed in a representative genome. However, when an environment changes, information can be lost. At the same time, information is processed by animal brains to survive in complex environments, and the capacity for information processing also evolves. Here I review applications of information theory to the evolution of proteins as well as to the evolution of information processing in simulated agents that adapt to perform a complex task.Comment: 25 pages, 7 figures. To appear in "The Year in Evolutionary Biology", of the Annals of the NY Academy of Science

Large-Scale Power Spectrum and Structures From the ENEAR galaxy Peculiar Velocity Catalog

We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiarvelocity data of the recently completed redshift-distance survey of early-type galaxies (ENEAR). The general results are in agreement with the high amplitude power spectra found from similar analysis of other independent all-sky catalogs of peculiar velocity data such as MARK III and SFI. For Lambda & Open CDM COBE normalized PS models, the best-fit parameters are confined by a contour approximately defined by Omega h^{1.3}=0.377+-0.08 and Omega h^{0.88}=0.517+-0.083, respectively. Gamma-shape models, free of COBE normalization, resultsin the weak constraint of $\Gamma \geq 0.17$ and in the rather stringent constraint of sigma_8 Omega^{0.6}=1.0+-0.25. All quoted uncertainties refer to 3-sigma confidence-level. The calculated PS is used as a prior for Wiener reconstruction of the density field at different resolutions and the three-dimensional velocity field within a volume of radius ~80 Mpc/h. All major structures in the nearby universe are recovered and are well matched to those predicted from all-sky redshift surveys.Comment: Submitted to MNRAS, 11 Pages, 9 figure

Cocaine abuse and effects in the serum levels of cytokines IL-6 and IL-10

AbstractBackgroundCocaine abuse is capable of activating the innate immune system in the CNS resulting in deregulation of homeostasis between pro and antiinflammatory cytokines. The aim of this study was to investigate serum levels of pro and antiinflammatory cytokines, IL-6 and IL-10 respectively, in cocaine users from a young population-based sample.MethodsThis is a case–control study nested in a cross-sectional population-based survey, with individuals of 18 and 35 years old. Two groups were selected: 24 healthy controls and 12 subjects who reported cocaine use. Serum IL-6 and IL-10 were measured by ELISA using a commercial kit.ResultsThere was a statistically significant increase in IL-6 (p=0.037) and decrease in IL-10 (p=0.007) serum levels, between cocaine users and the control group. There was also an increase in the ratio IL-6/IL-10 (p=0.013) among cocaine users individuals, when compared to the control group.ConclusionsOur results suggest that cocaine users showed an activation of the immune system when compared a control group, demonstrating a disruption in the balance of pro and antiinflammatory cytokines. Thus, peripheral cytokines may represent a putative biomarkers for cocaine users, contributing to the development of diagnosis and effective treatments