Strange Metallic Behaviour and the Thermodynamics of Charged Dilatonic Black Holes

We review a recent holographic analysis arXiv:1005.4690 of charged black holes with scalar hair in view of their applications to the cuprate high temperature superconductors. We show in particular that these black holes show an interesting phase structure including critical behaviour at zero temperature or charge, describe both conductors and insulators (including holographic Mott-like insulators), generically have no residual entropy and exhibit experimentally observed scaling relations between electronic entropy, specific heat and (linear) DC resistivity. Transport properties are discussed in the companion contribution to these proceedings.Comment: 6 pages, 6 figures, to appear in "Proceedings of the XVIth European Workshop on String Theory", Madrid, June 2010, to be published in Fortsch. Phy

Internal and external R&D: complements or substitutes? Evidence from a dynamic panel data model.

We examine the impact of internal and external R&D on labor productivity in a 6-year panel of 304 innovating firms. We apply a dynamic linear panel data model that allows for decreasing returns to scale in internal and external R&D with a non-linear approximation of changes in the knowledge stock. We find complementarity between internal and external R&D, with a positive impact of external R&D only evident in case of sufficient internal R&D. The findings confirm the role of internal R&D in enhancing absorptive capacity and hence the effective utilization of external knowledge. These results suggest that empirical studies examining complementarities between continuously measured practices should adopt more general non-linear specifications to allow for correct inferences.R&D; Panel data; Innovating firms; Knowledge; Empirical study; Specifications;

Testing for complementarity and substitutability in the case of multiple practices.

Recent empirical studies of firm-level performance have been concerned with establishing potential complementarity between more than two organizational practices. These papers have drawn conclusions on the basis of potentially biased estimates of pair-wise interaction effects between such practices. In this paper we develop a consistent testing framework based on multiple inequality constraints that derives from the definition of (strict) supermodularity as suggested by Athey and Stern (1998). Monte Carlo results show that the multiple restrictions test is superior for performance models with high explanatory power. If practices explain only a minor part of organizational performance no test is able to identify complementarity or substitutability in a satisfactory manner.Complementarity; Constraint; Effects; Empirical study; Firm performance; Framework; Interaction effects; Model; Models; Performance; Power; Studies; Supermodularity;

Do shareholders of acquiring firms gain from acquisitions?

We examine a sample of 12,023 acquisitions by public firms from 1980 to 2001. Shareholders of these firms lost a total of $218 billion when acquisitions were announced. Though shareholders lose throughout our sample period, losses associated with acquisition announcements after 1997 are dramatic. Small firms gain from acquisitions, so that shareholders of small firms gained$8 billion when acquisitions were announced and shareholders of large firms lost $226 billion. We examine the cross-sectional variation in the announcement returns of acquisitions. Small firm shareholders earn systematically more when acquisitions are announced. This size effect is typically more important than how an acquisition is financed and than the organizational form of the assets acquired. The only acquisitions that have positive aggregate gains are acquisitions of subsidiaries.

Confidence Level and Sensitivity Limits in High Contrast Imaging

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5sigma for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3*10^-7 confidence level detection threshold when averaging a partially correlated non-Gaussian noise.Comment: 29 pages, 13 figures, accepted to Ap

Introduction to the second international symposium of platial information science

People ‘live’ and constitute places every day through recurrent practices and experience. Our everyday lives, however, are complex, and so are places. In contrast to abstract space, the way people experience places includes a range of aspects like physical setting, meaning, and emotional attachment. This inherent complexity requires researchers to investigate the concept of place from a variety of viewpoints. The formal representation of place – a major goal in GIScience related to place – is no exception and can only be successfully addressed if we consider geographical, psychological, anthropological, sociological, cognitive, and other perspectives. This year’s symposium brings together place-based researchers from different disciplines to discuss the current state of platial research. Therefore, this volume contains contributions from a range of fields including geography, psychology, cognitive science, linguistics, and cartography

Attributes that influence resort attractiveness: a case study of selected Kimberley resorts

Published ArticleResorts have grown to dominate the accommodation sector of the world’s tourism industry and are known as the key building blocks of tourism due to the impact the latter has on local and international economies. Resorts, as a component of the destination offer a unique combination of resources, attractions, and facilities; they also have unique physical environments, ecological conditions, and socio-cultural specifics. The attractiveness of a resort plays a role in a tourist’s destination of choice, expectations of satisfaction, intentions to revisit, perceptions of benefits and motivations, positive perception of opinion leaders, the amount of money spent, and the duration of the stay. In order for a resort to be successful, sustainable and viable, it is important to identify the attributes that lead tourists to choose one destination over another. Despite this, a lack of research has been carried out to determine the underlying dimensions of resort attractiveness in South Africa. The aim of this research was to determine the attractiveness of selected Kimberley resorts in the Northern Cape, South Africa. These resorts have experienced low visitation and profit levels in the past. This leads to question whether visitors find the resorts attractive. In order to collect data a questionnaire was used to conduct interviews with visitors at the resorts. The results suggest that attributes of selected Kimberley resorts are perceived as being of average to poor quality

PREDICTION OF BOD AND COD OF A REFINERY WASTEWATER USING MULTILAYER ARTIFICIAL NEURAL NETWORKS

In the recent past, artificial neural networks (ANNs) have shown the ability to learn and capture non-linear static or dynamic behaviour among variables based on the given set of data. Since the knowledge of internal procedure is not necessary, the modelling can take place with minimum previous knowledge about the process through proper training of the network. In the present study, 12 ANN based models were proposed to predict the Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) concentrations of wastewater generated from the effluent treatment plant of a petrochemical industry. By employing the standard back error propagation (BEP) algorithm, the network was trained with 103 data points for water quality indices such as Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Phenol concentration, Ammoniacal Nitrogen (AMN), Total Organic Carbon (TOC) and Kjeldahl’s Nitrogen (KJN) to predict BOD and COD. After appropriate training, the network was tested with a separate test data and the best model was chosen based on the sum square error (training) and percentage average relative error (% ARE for testing). The results from this study reveal that ANNs can be accurate and efficacious in predicting unknown concentrations of water quality parameters through its versatile training process

The Implications of Content Analysis for the Interpretation of Unguentaria in Museum Collections

Scent has traditionally been an ephemeral component of rituals in ancient societies, including burial and other practices associated with the anointing of the body (Classen et al. 1994: 43; Houston and Taube 2000: 271). This thesis investigates the possible signifiers and social impact such scents might have had for individuals participating in such rituals by using the little explored approach of sensory archaeology. A discussion of the correlation between olfaction and the triggering of both the experiential and emotional aspects of memory contributes to a broader view of these rituals in the anthropological literature (Classen et al. 1994), while Houston and Taube\u27s work on scent in Mayan rituals provides a framework for applying sensory archaeology to Classical contexts (2000). Vessel contents are used as a proxy in this thesis for reconstructing the particular olfactory atmosphere associated with mortuary ritual in late Greek and early Roman cultural contexts. The residue spectra derived from the visible contents of twenty-seven out of a total of thirty-nine small glass and ceramic vials from collections at the Milwaukee Public Museum (MPM) are compared to other unguentaria residue studies as well as Greek and Roman written sources in which scented unguents, oils, perfumes, creams, and cosmetics are described to test the archaeological classification of this vessel category. Stylistic conventions are tested against data derived from content analysis rather than solely on the basis of assumed function implied by form. The chemical characterization of the contents of these vessels relies on the use of inductively coupled plasma-mass spectrometry (ICP-MS) and Fourier transform-infrared spectroscopy (FTIR). FT-IR was chosen for its successful application in a recent residue study of unguentaria (Ribechini et al. 2008a-b) while ICP-MS analysis was performed based upon its widespread application to the determination of sample origin