Axial symmetry cosmological constant vacuum solution of field equations with a curvature singularity, closed time-like curves and deviation of geodesics

In this paper, we present a type D, non-vanishing cosmological constant, vacuum solution of the Einstein's field equations, extension of an axially symmetric, asymptotically flat vacuum metric with a curvature singularity. The space-time admits closed time-like curves (CTCs) that appear after a certain instant of time from an initial spacelike hypersurface, indicating it represents a time-machine space-time. We wish to discuss the physical properties and show that this solution can be interpreted as gravitational waves of Coulomb-type propagate on anti-de Sitter space backgrounds. Our treatment focuses on the analysis of the equation of geodesic deviation.Comment: 17 pages, accepted for publication in Adv. High Energy Physics journa

Dissonance Reduction Strategies in Ride-Sharing Apps- A Case of Uber

Ride-sharing apps have both positive and negative impact in our daily lives. To study the negative impacts especially personal safety issues, this study explores the reaction of ride-sharing app users to such safety issues. We contextualize our study using a scenario-based survey. We found empirical support to all the hypotheses by surveying 421 individuals. This study contributes to the information systems literature in providing ways to apply dissonance reduction techniques that are a strong predictor of satisfaction. In addition, this study also addresses the safety issues faced by riders using ride-sharing apps and how co- creation would help address these issues

Technology Frustration and Consumer Valuation Shift for Mobile Apps: An Exploratory Study

Consumer evaluation of products in a market is a predictor of the success or failure of a product. For digital products, the usage of a product is determined by the technology robustness associated with the design of the product. Bad designs, implementation and integration issues lead to frustration on the part of consumers using the product. In this study, we explore how technology frustration negatively influences the valuation of a product in digital markets. Furthermore, we hypothesize that market externalities, such as consumer passion for, and sustenance of, the product in question temper this negative effect. Finally, we contend that the negative effect of technology frustration is high for new and high priced products because of the higher expectations and hence more stringent evaluations for new and high priced products by consumers. We conducted empirical analysis and found support for our hypotheses. Managerial and research contributions are discussed

Magnetic Resonance Imaging Appearance of Giant Intracerebral Tuberculoma: A Retrospective Analysis

Background: Giant intracerebral tuberculomas are rare lesions but should be considered in the differential diagnosis of intracranial space-occupying lesion in an endemic region. Objective: The purpose of this study is to analyze the clinical data and magnetic resonance imaging (MRI) findings of giant intracerebral tuberculomas to improve the diagnostic precision. Material and Methods: The clinical and MRI findings of 22 patients of giant intracerebral tuberculoma were analyzed retrospectively. For the statistical analysis independent sample Student t-test was used. Results: For 22 patients included in this sample the giant intracerebral tuberculoma was of size more than 2.5cm. The majority of the giant tuberculomas (19 patients (86.4%))was located in the supratentorial area.T2-weighted hypointense core of giant tuberculoma was observed in 12 patients (54.5%) and T1 hyperintensities were observed in peripheral (wall) of the giant tuberculoma in 14 patients (63.6%). The mean ADC value of the peripheral (wall) of the giant tuberculoma was 1.034± 0.466[SD] x 10-3mm2/s and the core was 0.994± 0.455[SD] x 10-3mm2/s with a statistically significant difference (p-value <0.0005) in between. MR spectroscopy showed raised lipid peak at 0.9 to 1.33 ppm in 10 patients (45.5%),raised lipid-lactate peak in 12 patients (54.5%),raised Choline/Cr ratio more than 1.2 in 14 patients(63.6%) and Choline/Cr ratio less than 1.2 in 5 patients (22.7%). Associated involvement of lung was observed in the 6patients (27.3%), cervical lymph node in 1 patient (4.5%) and spine in 1patient (4.5%). Conclusions: MRI plays a vital role in distinguishing giant intracerebral tuberculomas from other intracranial space-occupying lesions, thereby allows the early institution of anti-tubercular treatment (ATT), decreased patient morbidity, mortality, and prevents unnecessary neurosurgical excision

A comparison of hedonic and utilitarian digital products based on consumer evaluation and technology frustration

This study explores how hedonic mobile applications (apps) compare to utilitarian apps in consumer evaluation. We posit that achieving a set of passionate consumers is a pre-cursor to product success in markets, whereas technology frustration is a negative hindrance to the product success. Also, we argue that technology frustration may act as a negative complementing factor to consumer passion, and this effect is higher for hedonic products than utilitarian products. We contextualize our study to the android apps, and used a dataset that tracked 19,121 apps in the android market for three months and coded our variables from this dataset. We conducted empirical analysis and found support for our hypotheses. This study contributes to the information systems and marketing literature in providing a new dimension associated with consumer evaluation of digital products, and draws evaluative comparisons between hedonic and utilitarian digital products

The Role of Effectiveness, Appeal and Functionality on Evaluation of Health Apps

Mobile health applications (apps) are enabling health care service delivery through access to patients beyond service walls. A number of apps have emerged that help patients regarding information on diseases, treatment regimes, and taking informed decisions on health management. To sustain an app in the market, questions such as what functionalities influence a patient’s decision to use and evaluate the apps needs to be answered. A benchmark for sustained app use is the impact that the current evaluation has on the decision of the future users. This study explores the differential impact of effectiveness of health apps on patient evaluation change per week. Further, how the relationship between effectiveness and evaluation change differs across different app-functionalities and service appeal are explored. A dataset of 2,292 apps were used to conduct empirical analysis. We find that patients evaluate certain functionalities higher than others. Managerial and research contributions are also discussed

A Study of News Credibility and Trust on Social Media – A Multi-Cultural Evaluation

Information sharing is an important motivation for individuals to join social networking websites (SNSs). One source for the shared information are the posts that are shared in SNS. In this study, we propose a research model that represents antecedents of trust in posts in the SNS and the impact of culture. We plan to gather data from two countries- China and USA. We expect to find that content credibility and source credibility as antecedents of trust. In addition, we expect to find that involvement in the post moderates the effect of source credibility and content credibility on trust. Finally, we expect that source credibility and content credibility have the greatest impact on trust in the USA