Showing papers by "Swinburne University of Technology published in 2007"
TL;DR: It is possible to locate as well as download the wealth of networks how social production transforms markets and freedom Book.
2,097 citations
Book•
08 Feb 2007TL;DR: In this paper, the authors discuss the social psychology of brands and understand the meaning of brands in terms of emotion, emotion, and brand equity, as well as how to build brands through marketing communication.
Abstract: PART 1: THE SOCIO-CULTURAL MEANING OF BRANDS 1. Understanding the Social Psychology of Brands 2. Emotion and Brands 3. The Symbolic Meaning of Brands 4. Cultural Meaning Systems and Brands PART 2: BRAND EQUITY AND BRAND BUILDING 5. Brand Equity 6. Building Brands through Marketing Communication 7. Measuring Brand Performance and Equity PART 3: MANAGING BRANDS 8. Brand Strategies 1 - Symbolic brands 9. Brand Strategies 2 - Low-involvement brands 10. Brands, Innovation and High Technology 11. Brand Stretching and Retrenching 12. Managing Corporate Reputation
1,340 citations
TL;DR: The study demonstrates the usefulness of Rasch analysis in assessing the psychometric properties of a scale and suggests that further use of this technique to assess the HADS-14 in other clinical groups is warranted.
Abstract: Objectives To demonstrate the use of Rasch analysis by assessing the appropriateness of utilizing the Hospital Anxiety and Depression Scale (HADS) total score (HADS-14) as a measure of psychological distress.
Design Cross-sectional, using Rasch analysis.
Methods The HADS was administered to 296 patients attending an out-patient musculoskeletal rehabilitation program. Rasch analysis was conducted using RUMM2020 software to assess the overall fit of the model, the response scale used, individual item fit, differential item functioning (DIF) and person separation.
Results Rasch analysis supported the viability of the HADS-14 as a measure of psychological distress. It showed good person separation, little disordering of the thresholds and no evidence of DIF. One anxiety item (item 11) showed some misfit to the model. The residuals patterned into the two subscales (anxiety and depression), but the person estimate derived from these two subscales was not statistically different to that derived from all items taken together, supporting the assumption of unidimensionality. A cut-point of 12 on the HADS-14 identified all cases that were classified as both anxious and depressed on the original individual HADS subscales.
Conclusions The results of Rasch analysis support the use of the HADS-14 as a global measure of psychological distress. The study demonstrates the usefulness of Rasch analysis in assessing the psychometric properties of a scale and suggests that further use of this technique to assess the HADS-14 in other clinical groups is warranted.
885 citations
TL;DR: It is shown that a dividing T lymphocyte initially responding to a microbe exhibits unequal partitioning of proteins that mediate signaling, cell fate specification, and asymmetric cell division, suggesting a mechanism by which a single lymphocyte can apportion diverse cell fates necessary for adaptive immunity.
Abstract: A hallmark of mammalian immunity is the heterogeneity of cell fate that exists among pathogen-experienced lymphocytes. We show that a dividing T lymphocyte initially responding to a microbe exhibits unequal partitioning of proteins that mediate signaling, cell fate specification, and asymmetric cell division. Asymmetric segregation of determinants appears to be coordinated by prolonged interaction between the T cell and its antigen-presenting cell before division. Additionally, the first two daughter T cells displayed phenotypic and functional indicators of being differentially fated toward effector and memory lineages. These results suggest a mechanism by which a single lymphocyte can apportion diverse cell fates necessary for adaptive immunity.
837 citations
TL;DR: The authors show that building on existing theories by combining the best features of previous models--a nested modeling strategy that is commonly used in other areas of science but often neglected in psychology--results in better and more powerful computational models.
Abstract: At least 3 different types of computational model have been shown to account for various facets of both normal and impaired single word reading: (a) the connectionist triangle model, (b) the dual-route cascaded model, and (c) the connectionist dual process model. Major strengths and weaknesses of these models are identified. In the spirit of nested incremental modeling, a new connectionist dual process model (the CDP model) is presented. This model builds on the strengths of 2 of the previous models while eliminating their weaknesses. Contrary to the dual-route cascaded model, CDP is able to learn and produce graded consistency effects. Contrary to the triangle and the connectionist dual process models, CDP accounts for serial effects and has more accurate nonword reading performance. CDP also beats all previous models by an order of magnitude when predicting individual item-level variance on large databases. Thus, the authors show that building on existing theories by combining the best features of previous models—a nested modeling strategy that is commonly used in other areas of science but often neglected in psychology—results in better and more powerful computational models.
623 citations
TL;DR: A survey of the existing techniques for creating covert channels in widely deployed network and application protocols and an overview of common methods for their detection, elimination, and capacity limitation, required to improve security in future computer networks are given.
Abstract: Covert channels are used for the secret transfer of information. Encryption only protects communication from being decoded by unauthorised parties, whereas covert channels aim to hide the very existence of the communication. Initially, covert channels were identified as a security threat on monolithic systems i.e. mainframes. More recently focus has shifted towards covert channels in computer network protocols. The huge amount of data and vast number of different protocols in the Internet seems ideal as a high-bandwidth vehicle for covert communication. This article is a survey of the existing techniques for creating covert channels in widely deployed network and application protocols. We also give an overview of common methods for their detection, elimination, and capacity limitation, required to improve security in future computer networks.
543 citations
Swinburne University of Technology1, University of New South Wales2, National Technical University of Athens3, University of Miami4, Naval Postgraduate School5, United States Naval Research Laboratory6, European Centre for Medium-Range Weather Forecasts7, Delft University of Technology8, Arctic and Antarctic Research Institute9, Katholieke Universiteit Leuven10, University of Turin11, Engineer Research and Development Center12, University of Florida13, National Oceanic and Atmospheric Administration14
TL;DR: This paper tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems the authors presently face.
469 citations
TL;DR: The development of an FX-style correlator for very long baseline interferometry (VLBI), implemented in software and intended to run in multiprocessor computing environments, such as large clusters of commodity machines (Beowulf clusters) or computers specifically designed for high-performance computing, such ASM shared-memory machines.
Abstract: We describe the development of an FX-style correlator for very long baseline interferometry (VLBI), implemented in software and intended to run in multiprocessor computing environments, such as large clusters of commodity machines (Beowulf clusters) or computers specifically designed for high-performance computing, such as multiprocessor shared-memory machines. We outline the scientific and practical benefits for VLBI correlation, these chiefly being due to the inherent flexibility of software and the fact that the highly parallel and scalable nature of the correlation task is well suited to a multiprocessor computing environment. We suggest scientific applications where such an approach to VLBI correlation is most suited and will give the best returns. We report detailed results from the Distributed FX (DiFX) software correlator running on the Swinburne supercomputer (a Beowulf cluster of ∼300 commodity processors), including measures of the performance of the system. For example, to correlate all Stokes products for a 10 antenna array with an aggregate bandwidth of 64 MHz per station, and using typical time and frequency resolution, currently requires an order of 100 desktop- class compute nodes. Due to the effect of Moore's law on commodity computing performance, the total number and cost of compute nodes required to meet a given correlation task continues to decrease rapidly with time. We show detailed comparisons between DiFX and two existing hardware-based correlators: the Australian Long Baseline Array S2 correlator and the NRAO Very Long Baseline Array correlator. In both cases, excellent agreement was found between the correlators. Finally, we describe plans for the future operation of DiFX on the Swinburne supercomputer for both astrophysical and geodetic science.
379 citations
TL;DR: It is shown that psychologists can help identify the factors that influence new venture creation and success and inform the construction of public policy to facilitate entrepreneurship.
Abstract: Entrepreneurship is a major source of employment, economic growth, and innovation, promoting product and service quality, competition, and economic flexibility. It is also a mechanism by which many people enter the society's economic and social mainstream, aiding culture formation, population integration, and social mobility. This article aims to illuminate research opportunities for psychologists by exposing gaps in the entrepreneurship literature and describing how these gaps can be filled. A "call to action" is issued to psychologists to develop theory and undertake empirical research focusing on five key topic areas: the personality characteristics of entrepreneurs, the psychopathology of entrepreneurs, entrepreneurial cognition, entrepreneurship education, and international entrepreneurship. Methodological issues are discussed and recommendations provided. It is shown that psychologists can help identify the factors that influence new venture creation and success and inform the construction of public policy to facilitate entrepreneurship.
353 citations
TL;DR: It is found that the way that instructors post to forums may influence students' forum discussions and participation in unexpected ways and that intuitive measures such as the rate of student participation and the length of discussion threads are not necessarily good ways to judge the 'health' of discussion forums or the quality of learning taking place.
Abstract: As asynchronous discussion forums become more prevalent in online and flexible-delivery modes of teaching, understanding the role that instructors play in student learning in these forums becomes an important issue. Whether the instructor chooses to lead discussions or to keep a low profile can affect student participation in surprising ways. In this study, we investigate how instructor participation rates, the timing of instructor postings (during or at the end of a forum) and nature of their postings (questions, answers or a mix of the two) relate to student participation and perception. Using archives containing over 40,000 postings to nearly 400 discussion forums, together with over 500 university evaluation survey responses collected over six consecutive semesters, we analysed student and instructor postings to discussion forums, student responses to university evaluation surveys, and instructor and student responses to surveys carried out as part of this project. We collected both quantitative and qualitative responses on how instructors believe they behave in discussion forums and compared these with statistical analysis of the forums, and then looked at how the instructors' behaviour correlated with students' participation and perceptions. We found that the way that instructors post to forums may influence students' forum discussions and participation in unexpected ways. We show that instructors' perceptions of how they teach online do not necessarily agree with our observations, and that intuitive measures such as the rate of student participation and the length of discussion threads are not necessarily good ways to judge the 'health' of discussion forums or the quality of learning taking place.
314 citations
Australia Telescope National Facility1, Swinburne University of Technology2, York University3, Durham University4, University of Calgary5, University of Sydney6, University of Colorado Boulder7, University of Tasmania8, University of California, Berkeley9, University of Adelaide10, Laval University11, McGill University12, Herzberg Institute of Astrophysics13, California Institute of Technology14, La Trobe University15, University of Toronto16, Australian National University17, University of British Columbia18, University of Western Australia19, Curtin University20
TL;DR: The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors as mentioned in this paper.
Abstract: The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.
TL;DR: In this article, the authors present a precise estimate of the bulk virial scaling relation of halos formed via hierarchical clustering in an ensemble of simulated cold dark matter cosmologies.
Abstract: We present a precise estimate of the bulk virial scaling relation of halos formed via hierarchical clustering in an ensemble of simulated cold dark matter cosmologies. The result is insensitive to cosmological parameters, the presence of a trace, dissipationless gas component, and numerical resolution down to a limit of ~1000 particles. The dark matter velocity dispersion scales with total mass as log(sigma_{DM}(M,z)) = log(1082.9 +- 4.0 \kms) + (0.3361 +- 0.0026) log(h(z)M_{200}/10^{15} Msun), with h(z) the dimensionless Hubble parameter. At fixed mass, the velocity dispersion likelihood is nearly log-normal, with scatter sigma_{ln sigma} = 0.0426 +- 0.015, except for a tail to higher dispersions containing 10% of the population that are merger transients. We combine this relation with the halo mass function in LCDM models, and show that a low normalization condition, S_8 = sigma_8(Omega_m/0.3)^{0.35} \= 0.69, favored by recent WMAP and SDSS analysis requires that galaxy and gas specific energies in rich clusters be 50% larger than that of the underlying dark matter. Such large energetic biases are in conflict with the current generation of direct simulations of cluster formation. A higher normalization, S_8 = 0.80, alleviates this tension and implies that the hot gas fraction within r_{500} is (0.71 +- 0.09) h_{70}^{-3/2} Omega_b/\Omega_m, a value consistent with recent Sunyaev-Zel'dovich observations.
TL;DR: This work introduces a rationale-based architecture model that incorporates design rationale, design objects and their relationships and applies traceability techniques for change impact analysis and root-cause analysis, thereby allowing software architects to better understand and reason about an architecture design.
TL;DR: In this article, a least-squares regression analysis was performed to obtain a relation suitable for the purpose of predicting black hole masses in other galaxies, and the optimal relation was given by log Mbh = (7.98 ± 0.09) + (3.70 ± 0.46) log(n/3) -(3.10 − 0.84) [log n/3]2, with intrinsic = 0.31 dex.
Abstract: We reinvestigate the correlation between black hole mass and bulge concentration. With an increased galaxy sample (totaling 27) and updated estimates of galaxy distances, black hole masses, and Sersic indices n—a measure of concentration—we perform a least-squares regression analysis to obtain a relation suitable for the purpose of predicting black hole masses in other galaxies. In addition to the linear relation, log Mbh = (7.81 ± 0.08) + (2.69 ± 0.28) log(n/3) with intrinsic = 0.31 dex, we investigated the possibility of a higher order Mbh-n relation, finding the second-order term in the best-fitting quadratic relation to be inconsistent with a value of zero at greater than the 99.99% confidence level. The optimal relation is given by log Mbh = (7.98 ± 0.09) + (3.70 ± 0.46) log(n/3) - (3.10 ± 0.84) [log(n/3)]2, with intrinsic = 0.18 dex and a total absolute scatter of 0.31 dex. When the quadratic relation is extrapolated, it predicts black holes with masses of ~103 M☉ in n = 0.5 dwarf elliptical galaxies, compared to ~105 M☉ from the linear relation, and an upper bound on the largest black hole masses in the local universe equal to 1.2 × 109 M☉. In addition, we show that the nuclear star clusters at the centers of low-luminosity elliptical galaxies follow an extrapolation of the same quadratic relation, strengthening suggestions for a possible evolutionary link between supermassive black holes and nuclear star clusters. Moreover, we speculate that the merger of two such nucleated galaxies, accompanied by the merger and runaway collision of their central star clusters, could result in the late-time formation of some supermassive black holes. Finally, we predict the existence of, and provide equations for, an Mbh-μ0 relation, in which μ0 is the (extrapolated) central surface brightness of a bulge.
TL;DR: Key recommendations indicate the use of trauma-focused psychological therapy (cognitive behavioural therapy or eye movement desensitization and reprocessing in addition to in vivo exposure) as the most effective treatment for ASD and PTSD.
Abstract: Over the past 2-3 years, clinical practice guidelines (CPGs) for post-traumatic stress disorder (PTSD) and acute stress disorder (ASD) have been developed in the USA and UK. There remained a need, however, for the development of Australian CPGs for the treatment of ASD and PTSD tailored to the national health-care context. Therefore, the Australian Centre for Posttraumatic Mental Health in collaboration with national trauma experts, has recently developed Australian CPGs for adults with ASD and PTSD, which have been endorsed by the National Health and Medical Research Council (NHMRC). In consultation with a multidisciplinary reference panel (MDP), research questions were determined and a systematic review of the evidence was then conducted to answer these questions (consistent with NHMRC procedures). On the basis of the evidence reviewed and in consultation with the MDP, a series of practice recommendations were developed. The practice recommendations that have been developed address a broad range of clinical questions. Key recommendations indicate the use of trauma-focused psychological therapy (cognitive behavioural therapy or eye movement desensitization and reprocessing in addition to in vivo exposure) as the most effective treatment for ASD and PTSD. Where medication is required for the treatment of PTSD in adults, selective serotonin re-uptake inhibitor antidepressants should be the first choice. Medication should not be used in preference to trauma-focused psychological therapy. In the immediate aftermath of trauma, practitioners should adopt a position of watchful waiting and provide psychological first aid. Structured interventions such as psychological debriefing, with a focus on recounting the traumatic event and ventilation of feelings, should not be offered on a routine basis.
TL;DR: In this article, the authors combine the 2DF QSO Redshift Survey (2QZ) and the 2dF-Sloan Digital Sky Survey luminous red galaxy (LRG and QSO, hereafter 2SLAQ) in order to investigate the clustering of z∼ 1.5 QSOs and measure the correlation function (ξ).
Abstract: We combine the quasi-stellar object (QSO) samples from the 2dF QSO Redshift Survey (2QZ) and the 2dF-Sloan Digital Sky Survey luminous red galaxy (LRG) and QSO Survey (2dF-SDSS LRG and QSO, hereafter 2SLAQ) in order to investigate the clustering of z∼ 1.5 QSOs and measure the correlation function (ξ). The clustering signal in redshift-space and projected along the sky direction is similar to that previously obtained from the 2QZ sample alone. By fitting functional forms for ξ(σ, π), the correlation function measured along and across the line of sight, we find, as expected, that β, the dynamical infall parameter and Ω0m , the cosmological density parameter, are degenerate. However, this degeneracy can be lifted by using linear theory predictions under different cosmological scenarios. Using the combination of the 2QZ and 2SLAQ QSO data, we obtain: βQSO(z= 1.5) = 0.60+0.14−0.11, Ω0m= 0.25+0.09−0.07 which imply a value for the QSO bias, b(z= 1.4) = 1.5 ± 0.2 . The combination of the 2QZ with the fainter 2SLAQ QSO sample further reveals that QSO clustering does not depend strongly on luminosity at fixed redshift. This result is inconsistent with the expectation of simple 'high peaks' biasing models where more luminous, rare QSOs are assumed to inhabit higher mass haloes. The data are more consistent with models which predict that QSOs of different luminosities reside in haloes of similar mass. By assuming ellipsoidal models for the collapse of density perturbations, we estimate the mass of the dark matter haloes which the QSOs inhabit as ∼3 × 1012 h−1 M⊙ . We find that this halo mass does not evolve strongly with redshift nor depend on QSO luminosity. Assuming a range of relations which relate halo to black hole mass, we investigate how black hole mass correlates with luminosity and redshift, and ascertain the relation between Eddington efficiency and black hole mass. Our results suggest that QSOs of different luminosities may contain black holes of similar mass.
TL;DR: In this article, the age of a very r-process-enhanced metal-poor star HE 1523-0901 (Fe/H] = -2.95) was estimated based on the radioactive decay of Th and U.
Abstract: We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was found among a sample of bright metal-poor stars selected from the Hamburg/ESO Survey. From an abundance analysis of a high-resolution (R = 75,000) VLT/UVES spectrum, we find HE 1523-0901 to be strongly overabundant in r-process elements ([r/Fe] = 1.8). The abundances of heavy neutron-capture elements (Z > 56) measured in HE 1523-0901 match the scaled solar r-process pattern extremely well. We detect the strongest optical U line at 3859.57 A. For the first time, we are able to employ several different chronometers, such as the U/Th, U/Ir, Th/Eu, and Th/Os ratios to measure the age of a star. The weighted average age of HE 1523-0901 is 13.2 Gyr. Several sources of uncertainties are assessed in detail.
TL;DR: A degradable chain extender based on dl-lactic acid and ethylene glycol to accelerate hard segment degradation was developed to investigate the effect of incorporating DCE on synthesis, mechanical and thermal properties and in-vitro degradation.
TL;DR: Hyperactivation of the MFC during high- vs low-conflict conditions in patients with OCD may be a compensatory response to a neuronal abnormality in the region.
Abstract: Context: The medial frontal cortex (MFC), including the dorsal anterior cingulate and the supplementary motor area, is critical for adaptive and inhibitory control of behavior. Abnormally high MFC activity has been a consistent finding in functional neuroimaging studies of obsessive-compulsive disorder (OCD). However, the precise regions and the neural alterations associated with this abnormality remain unclear. Objective: To examine the functional and biochemical properties of the MFC in patients with OCD. Design: Cross-sectional study combining volumelocalized proton magnetic resonance spectroscopy and functional magnetic resonance imaging with a task encompassing inhibitory control processes (the MultiSource Interference Task) designed to activate the MFC. Setting: Healthy control participants and OCD patients recruited from the general community. Participants: Nineteen OCD patients (10 males and 9 females) and 19 age-, sex-, education-, and intelligencematched control participants recruited from the general community.
TL;DR: In this article, the authors derived the empirical BMGC-band internal attenuation-inclination relation for galaxy discs and their associated central bulges, leading to a direct constraint on the mean opacity of spiral discs.
Abstract: Based on our sample of 10 095 galaxies with bulge‐disc decompositions we derive the empirical BMGC-band internal attenuation‐inclination relation for galaxy discs and their associated central bulges. Our results agree well with the independently derived dust models of Tuffs et al., leading to a direct constraint on the mean opacity of spiral discs of τ f = 3.8 ± 0.7 (central face-on BMGC-band opacity). Depending on inclination, the BMGC-band attenuation correction varies from 0.2 to 1.1 mag for discs and from 0.8 to 2.6 mag for bulges. We find that, overall, 37 per cent of all BMGC-band photons produced in discs in the nearby Universe are absorbed by dust, a figure that rises to 71 per cent for bulge photons. The severity of internal dust extinction is such that one must incorporate internal dust corrections in all optical studies of large galaxy samples. This is particularly pertinent for optical Hubble Space Telescope comparative evolutionary studies as the dust properties will also be evolving. We use the new results to revise our recent estimates of the spheroid and disc luminosity functions. The implied stellar mass densities at redshift zero are somewhat higher than our earlier estimates: ρdiscs =
TL;DR: In this paper, the authors set out the current theoretical landscape of social enterprise governance and proposed an alternative theory that considers the influence of institutional pressures upon governance arrangements, and suggested a deeper analysis of institutional factors upon governance structure.
Abstract: This paper aims to set out the current theoretical landscape of social enterprise governance. It considers the two theories of governance currently advocated in the social enterprise literature - stakeholder and stewardship theories. Furthermore, it asserts the utility of neoinstitutional theory in analysis of social enterprise governance. The methodology employed was critical review and application of the prevailing governance theory in a social enterprise context. The prevailing institutional theory offers a great deal in explaining the governance dynamic in these organisations. The influence that values, symbols and cultural norms have upon organisation structure are not fully encompassed in social enterprise governance theory. Rather, it has been adapted and diluted to fit different explanations of governance, such as stakeholder and stewardship theory. Institutional theory offers an alternative lens with which to analyse social enterprise governance. This paper advocates institutional analysis of governance as an alternative method of mapping social enterprise governance, testing existing concepts such as isomorphism within the third sector, and new conceptual research. The paper consolidates the governance theory currently attributed to social enterprise governance, and puts forward an alternative theory that considers the influence of institutional pressures upon governance arrangements. It adds to the governance literature by suggesting a deeper analysis of institutional factors upon governance structure. It also adds to the growing literature that focuses on the governance of social enterprise as a distinct form of organisation in the third sector.
TL;DR: In this article, a clustering analysis of luminous red galaxies (LRGs) using nearly 9000 objects from the final, three-year catalogue of the 2dF-SDSS LRG and QSO (2SLAQ) Survey is presented.
Abstract: We present a clustering analysis of luminous red galaxies (LRGs) using nearly 9000 objects from the final, three-year catalogue of the 2dF-SDSS LRG and QSO (2SLAQ) Survey. We measure the redshift-space two-point correlation function, ξ(s) and find that, at the mean LRG redshift of shows the characteristic downturn at small scales (1 h−1 Mpc) expected from line-of-sight velocity dispersion. We fit a double power law to ξ(s) and measure an amplitude and slope of s0 = 17.3+2.5−2.0 h−1 Mpc, γ = 1.03 ± 0.07 at small scales (s 4.5 h−1 Mpc). In the semiprojected correlation function, wp(σ), we find a simple power law with γ = 1.83 ± 0.05 and r0 = 7.30 ± 0.34 h−1 Mpc fits the data in the range 0.4 < σ < 50 h−1 Mpc, although there is evidence of a steeper power law at smaller scales. A single power law also fits the deprojected correlation function ξ(r), with a correlation length of r0 = 7.45 ± 0.35 h−1 Mpc and a power-law slope of γ = 1.72 ± 0.06 in the 0.4 < r < 50 h−1 Mpc range. But it is in the LRG angular correlation function that the strongest evidence for non-power-law features is found where a slope of γ = −2.17 ± 0.07 is seen at 1 < r < 10 h−1 Mpc with a flatter γ = −1.67 ± 0.07 slope apparent at r 1 h−1 Mpc scales. We use the simple power-law fit to the galaxy ξ(r), under the assumption of linear bias, to model the redshift-space distortions in the 2D redshift-space correlation function, ξ(σ, π). We fit for the LRG velocity dispersion, wz, the density parameter, Ωm and β(z), where β(z) = Ω0.6m/b and b is the linear bias parameter. We find values of wz = 330 km s−1, Ωm = 0.10+0.35−0.10 and β = 0.40 ± 0.05. The low values for wz and β reflect the high bias of the LRG sample. These high-redshift results, which incorporate the Alcock–Paczynski effect and the effects of dynamical infall, start to break the degeneracy between Ωm and β found in low-redshift galaxy surveys such as 2dFGRS. This degeneracy is further broken by introducing an additional external constraint, which is the value β(z = 0.1) = 0.45 from 2dFGRS, and then considering the evolution of clustering from z 0 to zLRG 0.55. With these combined methods we find Ωm(z = 0) = 0.30 ± 0.15 and β(z = 0.55) = 0.45 ± 0.05. Assuming these values, we find a value for b(z = 0.55) = 1.66 ± 0.35. We show that this is consistent with a simple ����high-peak’ bias prescription which assumes that LRGs have a constant comoving density and their clustering evolves purely under gravity.
TL;DR: Erwin et al. as discussed by the authors showed that the optimal K-band relation is log(Mbh/M ⊙ ) = −0.37(± 0.04) with a total (not intrinsic) scatter in log Mbh equal to 0.33 dex.
Abstract: The differing Mbh-L relations presented in McLure & Dunlop, Marconi & Hunt and Erwin et al. have been investigated. A number of issues have been identified and addressed in each of these studies, including but not limited to: the removal of a dependency on the Hubble constant; a correction for dust attenuation in the bulges of disc galaxies; the identification of lenticular galaxies previously treated as elliptical galaxies; and application of the same (Y |X) regression analysis. These adjustments result in relations which now predict similar black hole masses. The optimal K-band relation is log(Mbh/M ⊙ ) = −0.37(±0.04)[MK + 24] + 8.29(±0.08), with a total (not intrinsic) scatter in log Mbh equal to 0.33 dex. This level of scatter is similar to the value of 0.34 dex from the Mbh-σ relation of Tremaine et al. and compares favourably with the value of 0.31 dex from the Mbh-n relation of Graham & Driver. Using different photometric data, consistent relations in the B- and R-band are also provided, although we do note that the small (N = 13) R-band sample used by Erwin et al. is found here to have a slope of −0.30 ± 0.06 and a total scatter of 0.31 dex. Performing a symmetrical regression on the larger K-band sample gives a slope of ∼ −0.40, implying Mbh ∝ L 1.00 . Implications for galaxy-black hole coevolution, in terms of dry mergers, are briefly discussed, as are the predictions for intermediate mass black holes. Finally, as previously noted by Tundo et al., a potential bias in the galaxy sample used to define the Mbh-L relations is shown and a corrective formula provided.
TL;DR: A detailed study of human Scribble function in the polarized mammary cell line, MCF10A is undertaken and identifies an essential role for mammalian Scribble in the regulation of the polarity specifically involved in directed epithelial migration.
Abstract: Altered expression of human Scribble is associated with invasive epithelial cancers, however, its role in tumour development remains unclear. Mutations in Drosophila Scribble result in loss of polarity, overproliferation and 3D-tumourous overgrowth of epithelial cells. Using complementation studies in Drosophila we recently demonstrated that expression of human Scribble can also regulate polarity and restrict tissue overgrowth. Here, we have undertaken a detailed study of human Scribble function in the polarized mammary cell line, MCF10A. We show that although Scribble does not seem to be required for apical-basal polarity or proliferation control in MCF10A cells, Scribble is essential for the control of polarity associated with directed epithelial cell migration. Scribble-depleted MCF10A cells show defective in vitro wound closure and chemotactic movement. The cells at the wound edge fail to polarize, show reduced lamellipodia formation and impaired recruitment of Cdc42 and Rac1 to the leading edge. Furthermore, we show that this function is relevant in vivo as Scribble mutant mice show defective epidermal wound healing. This data identifies an essential role for mammalian Scribble in the regulation of the polarity specifically involved in directed epithelial migration.
TL;DR: A unified analytical model is developed and it is proved that the binary exponential backoff mechanism induces a heavy-tailed delay distribution for the case of unlimited retransmissions and suggests that DCF is prone to long delays and not suited to carrying delay-sensitive applications.
Abstract: The MAC access delay in a saturated IEEE 802.11 DCF wireless LAN is analyzed. We develop a unified analytical model and obtain explicit expressions for the first two moments as well as the generating function. We show via comparison with simulation that our model accurately predicts the mean, standard deviation, and distribution of the access delay for a wide range of operating conditions. In addition, we show that the obtained generating function is much more accurate than others that have appeared in the literature. Using our model, we prove that the binary exponential backoff mechanism induces a heavy-tailed delay distribution for the case of unlimited retransmissions. We show using numerical examples that the distribution has a truncated power-law tail when a retransmission limit exists. This finding suggests that DCF is prone to long delays and not suited to carrying delay-sensitive applications
TL;DR: Children with Autism Spectrum Disorders (ASD) and children with Obsessive Compulsive Disorder (OCD) were compared on a range of repetitive behaviours; both groups reported more compulsions and obsessions than a typically developing comparison group.
Abstract: Children with Autism Spectrum Disorders (ASD) and children with Obsessive Compulsive Disorder (OCD) were compared on a range of repetitive behaviours. Parents reported similar levels of sameness behaviour and repetitive movements in the clinical groups, although children with OCD engaged in more repetitive behaviour focussed around routines and rituals. Children with OCD reported more compulsions and obsessions than children with ASD; both groups reported more compulsions and obsessions than a typically developing comparison group. Types of compulsions and obsessions tended to be less sophisticated in children with ASD than those with OCD. Sameness behaviour was more prevalent in younger children with OCD, but for children with ASD, age was not significantly related to sameness behaviour, repetitive movements, compulsions, or obsessions.
TL;DR: Extraversion had a direct, positive effect on physical and psychological strain, and there was preliminary support for a moderating role of Conscientiousness in the perceived stressor-strain relationship.
Abstract: The role of the Big Five traits in the occupational stressor-strain relationship was investigated among 211 managers. Direct, mediated, and moderated effect models were used to investigate whether the Big Five affect strain directly (independently of stress), indirectly (via stress and coping), or interactively with stress. Personality, stress, coping, and strain variables were measured and analyzed with path analysis and hierarchical regression. The Neuroticism-physical strain relationship was partially mediated by perceived role conflict and substance use, and the Neuroticism-psychological strain relationship was mediated by perceived stress. Extraversion had a direct, positive effect on physical and psychological strain, and there was preliminary support for a moderating role of Conscientiousness in the perceived stressor-strain relationship. Agreeableness and Openness were unrelated to strain.
TL;DR: In this paper, the surface brightness profiles of five cD galaxies were analyzed using deep R-band images, down to a limiting surface brightness of 26.5 R-mag arcsec −2.
Abstract: We have analysed deep R-band images, down to a limiting surface brightness of 26.5 R-mag arcsec −2 (equivalent to ∼28 B-mag arcsec −2 ), of five cD galaxies to determine the shape of the surface brightness profiles of their extended stellar envelopes. Both de Vaucouleurs R 1/4 and Sersic R 1/n models, on their own, provide a poor description of the surface brightness profiles of cD galaxies. This is due to the presence of outer stellar envelopes, thought to have accumulated over the merger history of the central cluster galaxy and also from the tidal stripping of galaxies at larger cluster radii. We therefore simultaneously fit two Sersic functions to measure the shape of the inner and outer components of the cD galaxies. We show that, for three out of our five galaxies, the surface brightness profiles are best fitted by an inner Sersic model, with indices n ∼ 1-6, and an outer exponential component. For these systems, the galaxy-to-envelope size ratio is 0.1-0.4 and the contribution of the stellar envelope to the total R-band light (i.e. galaxy + envelope) is around 60-80 per cent (based on extrapolation to a 300 kpc radius). The exceptions are NGC 6173, for which our surface brightness profile modelling is consistent with just a single component (i.e. no envelope) and NGC 4874 which appears to have an envelope with a de Vaucouleurs, rather than exponential, profile.
TL;DR: In this research, the service level agreements for a service composition are established through autonomous agent negotiation and an innovative framework is proposed in which the service consumer is represented by a set of agents who negotiate quality of service constraints with the service providers for various services in the composition.
TL;DR: Significant improvements in overall quality of life and two specific areas of daily living in people with low vision were found, although the magnitude and clinical significance of the rehabilitation-induced gains were modest.
Abstract: PURPOSE. To evaluate the effectiveness of a multidisciplinary low-vision rehabilitation program on quality of life evaluated by the Impact of Vision Impairment (IVI) instrument. METHODS. First-time referrals to low-vision clinics were assessed before and after rehabilitation (3– 6 months). Rasch analysis was used to estimate the three IVI subscale and overall values on an interval scale. A mixed between–within subjects ANOVA was used to identify whether presenting visual acuity had an interaction effect with rehabilitation change. Cohen d values were used to estimate the magnitude of the change and the standardized response mean (SRM) procedure was selected to determine the clinical significance of the rehabilitationinduced changes. RESULTS. One hundred twenty-four women and 68 men (mean age, 80.3 years) completed the rehabilitation. Most had agerelated macular degeneration (62%, 119) and were moderately to severely vision impaired (6/18; 78%, 149). After rehabilitation, significant improvements were recorded for the overall IVI score (P 0.006) and two subscales: reading and accessing information and emotional well-being (P 0.007 and 0.009, respectively). No significant improvement was found on the mobility and independence subscale (P 0.07). The magnitude of the postintervention improvement was found to be relatively moderate (Cohen d 0.17– 0.30) and clinically modest (SRM 0.22– 0.42). CONCLUSIONS. Significant improvements in overall quality of life and two specific areas of daily living in people with low vision were found, although the magnitude and clinical significance of the rehabilitation-induced gains were modest. Further investigation in other models of low-vision rehabilitation is needed to optimize quality of life gains in people with low vision. (Invest Ophthalmol Vis Sci. 2007;48:1476 –1482) DOI: