Energy Conservation and Hawking Radiation

The conservation of energy implies that an isolated radiating black hole cannot have an emission spectrum that is precisely thermal. Moreover, the no-hair theorem is only approximately applicable. We consider the implications for the black hole information puzzle.Comment: 6 pages, LaTex; v2: references adde

A Comparison of Moderate Oral Sedation Drug Regimens for Pediatric Dental Treatment: A Pilot Study

Purpose: Compare moderate oral sedation of pediatric patients using Hydroxyzine and Meperidine with either Diazepam or Midazolam in management of pediatric dental patients. Methods: Randomized, double-blind, crossover pilot study of patients 3 to 7 years of age requiring two sedation visits. Frankl and Houpt behavior scores recorded at injection time, initiation of treatment and 100% oxygen at end of treatment. Postoperative phone call surveys conducted within eight hours and within 24 hours of discharge. Wilcoxon Signed-Rank tests, Fisher’s Exact Chi-squared test and 0.10 significance level. Results: 25 subjects completed 35 sedations. Eight participants completed both treatments and demonstrated significantly higher total Houpt Scores with Diazepam at all treatment stages. Frankl scores favored Diazepam at injection time. More abnormal behavior was found with Midazolam, less memory of the visit with Diazepam, but longer sleep time with Diazepam. Conclusions: Sedation with the Hydroxyzine, Meperidine and Diazepam regimen may allow for a better overall sedation experience. Postoperative monitoring is essential. The results are promising and demonstrate the value of a larger study on sedation with Diazepam

The Volume of Black Holes

We propose a definition of volume for stationary spacetimes. The proposed volume is independent of the choice of stationary time-slicing, and applies even though the Killing vector may not be globally timelike. Moreover, it is constant in time, as well as simple: the volume of a spherical black hole in four dimensions turns out to be just ${4 \over 3} \pi r_+^3$. We then consider whether it is possible to construct spacetimes that have finite horizon area but infinite volume, by sending the radius to infinity while making discrete identifications to preserve the horizon area. We show that, in three or four dimensions, no such solutions exist that are not inconsistent in some way. We discuss the implications for the interpretation of the Bekenstein-Hawking entropy.Comment: 8 pages, revte

The unreasonable effectiveness of experiments in constraining nova nucleosynthesis

Classical nova explosions arise from thermonuclear ignition in the envelopes of accreting white dwarfs in close binary star systems. Detailed observations of novae have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. These phenomena are unusual in nuclear astrophysics because most of the thermonuclear reaction rates thought to be involved are constrained by experimental measurements. This situation allows for rather precise statements to be made about which measurements are still necessary to improve the nuclear physics input to astrophysical models. We briefly discuss desired measurements in these environments with an emphasis on recent experimental progress made to better determine key rates.Postprint (published version

Understanding Image Virality

Virality of online content on social networking websites is an important but esoteric phenomenon often studied in fields like marketing, psychology and data mining. In this paper we study viral images from a computer vision perspective. We introduce three new image datasets from Reddit, and define a virality score using Reddit metadata. We train classifiers with state-of-the-art image features to predict virality of individual images, relative virality in pairs of images, and the dominant topic of a viral image. We also compare machine performance to human performance on these tasks. We find that computers perform poorly with low level features, and high level information is critical for predicting virality. We encode semantic information through relative attributes. We identify the 5 key visual attributes that correlate with virality. We create an attribute-based characterization of images that can predict relative virality with 68.10% accuracy (SVM+Deep Relative Attributes) -- better than humans at 60.12%. Finally, we study how human prediction of image virality varies with different `contexts' in which the images are viewed, such as the influence of neighbouring images, images recently viewed, as well as the image title or caption. This work is a first step in understanding the complex but important phenomenon of image virality. Our datasets and annotations will be made publicly available.Comment: Pre-print, IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 201

Leveraging Visual Question Answering for Image-Caption Ranking

Visual Question Answering (VQA) is the task of taking as input an image and a free-form natural language question about the image, and producing an accurate answer. In this work we view VQA as a "feature extraction" module to extract image and caption representations. We employ these representations for the task of image-caption ranking. Each feature dimension captures (imagines) whether a fact (question-answer pair) could plausibly be true for the image and caption. This allows the model to interpret images and captions from a wide variety of perspectives. We propose score-level and representation-level fusion models to incorporate VQA knowledge in an existing state-of-the-art VQA-agnostic image-caption ranking model. We find that incorporating and reasoning about consistency between images and captions significantly improves performance. Concretely, our model improves state-of-the-art on caption retrieval by 7.1% and on image retrieval by 4.4% on the MSCOCO dataset

Psychological contract and knowledge management mediated by cultural dynamics

Contact centres are the vital link in the value chain between the organisation and its customers because they offer essential front line sales and services of products. Evaluation of their success can be assessed in terms of customer retention, up selling and the promotion of the brand. This is brought into sharp focus if the centre is outsourced because of the impact of the strategic behaviour of the principal and its relation with its agents. The association of employees with the brand in outsourced operation is not as effective as in captive operations partly because communications from principal to agent are attenuated. Emotional connectivity, diagnostic skill set, requirement gathering, and knowledge are some of the most sensitive qualities required in agents working in the contact centres. These characteristics are found to differ according to whether this is in-house or outsourced operation and affect the psychological contract between the service provider and its employees. In addition, the employees are unlikely to achieve any rewards and are unable to offer any commitments to the customer in an outsourced operation; hence the “psychological contract” is breached. One of the consequences of this breach is on knowledge management. The knowledge of an employee regarding the products and services is lost with that employee’s attrition. Also employees’ then have little interest towards customer service and organizational welfare, which impacts on the customer centric goals of the principal. We argue that the psychological contract between employer and an employee and has positive influence on Knowledge Diffusion, mediated by cultural dynamics, which further contributes to the overall organizational effectiveness. This paper aims to investigate, as a pilot study, the elements of organisational culture and secondly its role in the diffusion of knowledge in contact centres, in-house and outsourced. We demonstrate how by deploying a blend of qualitative methods, it is possible to perceive the effect of each element of the cultural web on diffusion. Finally we propose a hypothesis of the role that Power Distance (Hofstede, 1980) can play, as a proxy for the Psychological Contract to leverage knowledge diffusion