Gravitational Instantons from Minimal Surfaces

Physical properties of gravitational instantons which are derivable from minimal surfaces in 3-dimensional Euclidean space are examined using the Newman-Penrose formalism for Euclidean signature. The gravitational instanton that corresponds to the helicoid minimal surface is investigated in detail. This is a metric of Bianchi Type $VII_0$, or E(2) which admits a hidden symmetry due to the existence of a quadratic Killing tensor. It leads to a complete separation of variables in the Hamilton-Jacobi equation for geodesics, as well as in Laplace's equation for a massless scalar field. The scalar Green function can be obtained in closed form which enables us to calculate the vacuum fluctuations of a massless scalar field in the background of this instanton.Comment: One figure available by fax upon request. Abstract missing in original submission. Submitted to Classical and Quantum Gravit

Applications of Temperley-Lieb algebras to Lorentz lattice gases

Motived by the study of motion in a random environment we introduce and investigate a variant of the Temperley-Lieb algebra. This algebra is very rich, providing us three classes of solutions of the Yang-Baxter equation. This allows us to establish a theoretical framework to study the diffusive behaviour of a Lorentz Lattice gas. Exact results for the geometrical scaling behaviour of closed paths are also presented.Comment: 10 pages, latex file, one figure(by request

Inattentive Consumers in Markets for Services

In an experiment on markets for services, we find that consumers are likely to stick to default tariffs and achieve suboptimal outcomes. We find that inattention to the task of choosing a better tariff is likely to be a substantial problem in addition to any task and tariff complexity effect. The institutional setup on which we primarily model our experiment is the UK electricity and gas markets, and our conclusion is that the new measures by the UK regulator Ofgem to improve consumer outcomes are likely to be of limited impact

The relationship between China’s Airway Freight in terms of carbon-dioxide emission and export volume

China is one of the leading economies in the world in terms of both exports and production, requiring a sophisticated logistical system. Given that transportation causes carbon-dioxide (CO2) emissions, this paper analyzes the impact of China’s Airway Freight industry on CO2 emissions through econometric models such as linear regression and the Johansen Co-integration tests, with the ultimate goal of understanding the extent of the freight industry’s influence on carbon dioxide emissions. The effect of airway freight on CO2 emissions has been especially studied between the years 1980 and 2011. © International Economic Society

“Smartphone apps are cool, but do they help me?”: A qualitative interview study of adolescents’ perspectives on using smartphone interventions to manage nonsuicidal self-injury

Nonsuicidal self-injury (NSSI) is a major mental health problem associated with negative psychosocial outcomes and it most often starts in early adolescence. Despite this, adolescents are rarely involved in informing the development of interventions designed to address their mental health problems. This study aimed to (1) assess adolescents’ needs and preferences about future interventions that are delivered through smartphones and (2) develop a framework with implications for designing engaging digital mental health interventions. Fifteen adolescent girls, aged 12– 18 years, who met diagnostic criteria for a current NSSI disorder and were in contact with mental health services, participated in semi-structured interviews. Following a reflexive thematic analysis approach, this study identified two main themes: (1) Experiences of NSSI (depicts the needs of young people related to their everyday experiences of managing NSSI) and (2) App in Context (por-trays preferences of young people about smartphone interventions and reflects adolescents’ views on how technology itself can improve or hinder engaging with these interventions). Adolescent patients expressed interest in using smartphone mental health interventions if they recognize them as helpful, relevant for their life situation and easy to use. The developed framework suggests that digital mental health interventions are embedded in three contexts (i.e., person using the interven-tion, mental health condition, and technology-related factors) which together need to inform the development of engaging digital resources. To achieve this, the cooperation among people with lived experience, mental health experts, and human computer interaction professionals is vital

INVESTIGATION OF THE COMPATIBILITY OF FASILLAR AND EFLATUNPINAR HITΤITE MONUMENTS WITH CLOSE-RANGE PHOTOGRAMMETRIC TECHNIQUE

There are two Hittite monuments in Konya whose names are Eflatunpınar and Fasıllar. Eflatunpınar is located approximately 25 km at the North of Beysehir town within Konya province in Turkey. Eflatunpınar monument is belonging to Hittite Empire Age, was known since XIX century. It is an open air temple of Hittite, 6.60 m wide and 7 m high, was built with large block stones. The second one known as Fasıllar Hittite monument lies on a hillside next to the Fasıllar village which is 16 km east of Beysehir town and it is a high relief monument which is made of basalt rock. It is commonly accepted that these two monuments had never been completely finished. J. Mellaart have suggested that Fasıllar monument was not in-situ position, it was moved from Eflatunpınar to Fasıllar village by the local people for decoration purposes. This means that ac-cording to J. Mellaart, Fasıllar monument is the part of Eflatunpınar monument. The objective of this study is to investigate whether Fasıllar monument was built for placing on the top of Eflatunpınar monument which is firstly raised a subject by J. Mellaart. For this purpose, three-dimensional (3D) digital model was created for each monument by close-range photogrammetric technique. By the help of the 3D digital models of these monuments, the unity between the monuments were investigated as an engineering approach

Addressing Social Determinants of Health for Marginalized Populations: The Affordances of Digital Interventions

The World Health Organization describes the Social Determinants of Health (SDOH) as non-medical factors that influence the health outcomes of individuals such as the economic, social and physical environments. Marginalized communities face complex SDOH that limit an individual’s ability to cope with disorders due to recurring problems including poverty, limited access to affordable health services, substance use disorder (SUD) and material deprivation. In the context of marginalized populations, our study focused on Justice-Involved People (JIPs) who are under probation. Post incarceration, individuals experience challenges including high rates of homelessness and poor access to coordinated healthcare or other SDOH services. Although post-release models exist, these models are scarce and stigmatization toward JIPs and limited service availability are commonly observed in healthcare settings. In the criminal justice system, JIPs can be encouraged through non-clinical support from Digital Health Interventions to attend appointments, continue SUD treatment and access SDOH services. The smooth transition of JIPs back to their communities, facilitated by digital interventions, could address social isolation. The Probation/Parole and Reentry Coach App (PARCA) platform facilitates communication, between probation officers (POs) and JIPs, through a Justice Team Portal for POs and a mobile application for JIPs. JIPs can set and achieve personal goals related to employment, housing, substance use treatment, and healthcare. The dual functionality of the platform allows POs to monitor the progress and schedule appointments. The pilot implementation of PARCA was completed in two research sites in Texas, United States. We collected data from two cohorts of POs and JIPs. First, we conducted baseline interviews shortly after onboarding procedures. Second, we conducted follow-up interviews two weeks after the usage periods, focusing on PARCA features and feedback. Data analysis is ongoing, in accordance with technology affordance, which refers to what is offered or provided to the user by an object (Gibson 1986). Qualitative data revealed that JIPs need to make sense of the technology in relation to their personal goals and environment. However, when technology artifacts are irrelevant to their needs, it challenges JIPs’ sensemaking and limits the range of the affordances and utilization of the technology

Affordances of Digital Interventions to Support Adults on Probation: A Grounded Theory Approach

Information Technology (IT) based products hold great promise in supporting the significant number of individuals on probation, a marginalized population. This paper investigates how IT products designed for marginalized populations present distinct affordances. In this qualitative study, we used a grounded theory approach to interpret the affordances of the Probation and Reintegration Coach App (PARCA) digital product. Our study included 29 adults on probation before and after they used PARCA for 2 weeks. Our analysis of the interview data revealed four key affordances: self-monitoring, information access, engagement, and community support. Our findings confirmed that these affordances are not solely derived from technological features but emerge through user interactions with technology features and contextual factors that motivate the interactions. Hence, these affordances are inherently relational, particularly when designed for marginalized communities. Finally, we outline future research plans based on our findings. Keywords: Marginalized populations, digital intervention, affordances, adults on probatio

Testing the transportation-induced environmental Kuznets curve hypothesis: Evidence from eight developed and developing countries

This paper focuses on the relationship between air transportation, economic growth, and carbon emissions in 8 developing and 8 developed countries during the period 1980-2013 by testing the Environmental Kuznets Curve (EKC) hypothesis. We use annual panel data from the World Bank in order to demonstrate environmental sensibility of both developed and developing countries. In this context, the research results demonstrate that environmental sensitivity is pretty low for both developed and developing countries in the period 1980-2000. Afterwards, the environmental issues of the two groups of countries are evaluated over the period from 2001 to 2013 and the research results indicate that their sensitiveness has increased remarkably, which supports the inverse-U shape of the EKC. These empirical results are also consistent with the Kyoto protocol’s political aims and goals. In addition, based on the Johansen co-integration test results, there is a long-term stable relationship between as air transportation, CO2 emissions, energy use, and gross domestic product for both developed and developing countries, with the exception of Colombia and Turkey. © 2018, Econjournals. All rights reserved