scholarly journals QUANTUM SINGULARITIES IN STATIC AND CONFORMALLY STATIC SPACE-TIMES

2011 ◽  
Vol 26 (22) ◽  
pp. 3878-3888 ◽  
Author(s):  
D. A. KONKOWSKI ◽  
T. M. HELLIWELL

The definition of quantum singularity is extended from static space-times to conformally static space-times. After the usual definitions of classical and quantum singularities are reviewed, examples of quantum singularities in static space-times are given. These include asymptotically power-law space-times, space-times with diverging higher-order differential invariants, and a space-time with a 2-sphere singularity. The theory behind quantum singularities in conformally static space-times is followed by an example, a Friedmann-Robertson-Walker space-time with cosmic string. The paper concludes by discussing areas of future research.

2011 ◽  
Vol 03 ◽  
pp. 364-374 ◽  
Author(s):  
D. A. KONKOWSKI ◽  
T. M. HELLIWELL

The definition of quantum singularity is extended from static space-times to conformally static space-times. After the usual definitions of classical and quantum singularities are reviewed, examples of quantum singularities in static space-times are given. These include asymptotically power-law space-times, space-times with diverging higher-order differential invariants, and a space-time with a 2-sphere singularity. The theory behind quantum singularities in conformally static space-times is followed by an example, a Friedmann-Robertson-Walker space-time with cosmic string. The paper concludes by discussing areas of future research.


2011 ◽  
Vol 03 (04) ◽  
pp. 217-227 ◽  
Author(s):  
SAMI ATIF ◽  
ANJAN BISWAS ◽  
ESSAID ZERRAD

The quasi-stationary solitons for Langmuir waves in plasmas is obtained in this paper. This model is governed by the perturbed nonlinear Schrödinger's equation with cubic and power law nonlinearities. The perturbation terms are considered with full nonlinearity. A new generalized definition of the phase of the soliton is introduced. This leads to additional information at higher order level which soliton perturbation theory fails to capture.


2008 ◽  
Vol 29 (4) ◽  
pp. 205-216 ◽  
Author(s):  
Stefan Krumm ◽  
Lothar Schmidt-Atzert ◽  
Kurt Michalczyk ◽  
Vanessa Danthiir

Mental speed (MS) and sustained attention (SA) are theoretically distinct constructs. However, tests of MS are very similar to SA tests that use time pressure as an impeding condition. The performance in such tasks largely relies on the participants’ speed of task processing (i.e., how quickly and correctly one can perform the simple cognitive tasks). The present study examined whether SA and MS are empirically the same or different constructs. To this end, 24 paper-pencil and computerized tests were administered to 199 students. SA turned out to be highly related to MS task classes: substitution and perceptual speed. Furthermore, SA showed a very close relationship with the paper-pencil MS factor. The correlation between SA and computerized speed was considerably lower but still high. In a higher-order general speed factor model, SA had the highest loading on the higher-order factor; the higher-order factor explained 88% of SA variance. It is argued that SA (as operationalized with tests using time pressure as an impeding condition) and MS cannot be differentiated, at the level of broad constructs. Implications for neuropsychological assessment and future research are discussed.


2021 ◽  
Vol 42 (1) ◽  
pp. e8-e16 ◽  
Author(s):  
Angelica Tiotiu

Background: Severe asthma is a heterogeneous disease that consists of various phenotypes driven by different pathways. Associated with significant morbidity, an important negative impact on the quality of life of patients, and increased health care costs, severe asthma represents a challenge for the clinician. With the introduction of various antibodies that target type 2 inflammation (T2) pathways, severe asthma therapy is gradually moving to a personalized medicine approach. Objective: The purpose of this review was to emphasize the important role of personalized medicine in adult severe asthma management. Methods: An extensive research was conducted in medical literature data bases by applying terms such as “severe asthma” associated with “structured approach,” “comorbidities,” “biomarkers,” “phenotypes/endotypes,” and “biologic therapies.” Results: The management of severe asthma starts with a structured approach to confirm the diagnosis, assess the adherence to medications and identify confounding factors and comorbidities. The definition of phenotypes or endotypes (phenotypes defined by mechanisms and identified through biomarkers) is an important step toward the use of personalized medicine in asthma. Severe allergic and nonallergic eosinophilic asthma are two defined T2 phenotypes for which there are efficacious targeted biologic therapies currently available. Non-T2 phenotype remains to be characterized, and less efficient target therapy exists. Conclusion: Despite important progress in applying personalized medicine to severe asthma, especially in T2 inflammatory phenotypes, future research is needed to find valid biomarkers predictive for the response to available biologic therapies to develop more effective therapies in non-T2 phenotype.


Author(s):  
Fred Luthans ◽  
Carolyn M. Youssef

Over the years, both management practitioners and academics have generally assumed that positive workplaces lead to desired outcomes. Unlike psychology, considerable attention has also been devoted to the study of positive topics such as job satisfaction and organizational commitment. However, to place a scientifically based focus on the role that positivity may play in the development and performance of human resources, and largely stimulated by the positive psychology initiative, positive organizational behavior (POB) and psychological capital (PsyCap) have recently been introduced into the management literature. This chapter first provides an overview of both the historical and contemporary positive approaches to the workplace. Then, more specific attention is given to the meaning and domain of POB and PsyCap. Our definition of POB includes positive psychological capacities or resources that can be validly measured, developed, and have performance impact. The constructs that have been determined so far to best meet these criteria are efficacy, hope, optimism, and resiliency. When combined, they have been demonstrated to form the core construct of what we term psychological capital (PsyCap). A measure of PsyCap is being validated and this chapter references the increasing number of studies indicating that PsyCap can be developed and have performance impact. The chapter concludes with important future research directions that can help better understand and build positive workplaces to meet current and looming challenges.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malin Indremo ◽  
Richard White ◽  
Thomas Frisell ◽  
Sven Cnattingius ◽  
Alkistis Skalkidou ◽  
...  

AbstractThe aim of this study was to examine the validity of the Gender Dysphoria (GD) diagnoses in the Swedish National Patient Register (NPR), to discuss different register-based definitions of GD and to investigate incidence trends. We collected data on all individuals with registered GD diagnoses between 2001 and 2016 as well as data on the coverage in the NPR. We regarded gender confirming medical intervention (GCMI) as one proxy for a clinically valid diagnosis and calculated the positive predictive value (PPV) for receiving GCMI for increasing number of registered GD diagnoses. We assessed crude and coverage-adjusted time trends of GD during 2004–2015 with a Poisson regression, using assigned sex and age as interaction terms. The PPV for receiving GCMI was 68% for ≥ 1 and 79% for ≥ 4 GD-diagnoses. The incidence of GD was on average 35% higher with the definition of ≥ 1 compared to the definition of ≥ 4 diagnoses. The incidence of GD, defined as ≥ 4 diagnoses increased significantly during the study period and mostly in the age categories 10–17 and 18–30 years, even after adjusting for register coverage. We concluded that the validity of a single ICD code denoting clinical GD in the Swedish NPR can be questioned. For future research, we propose to carefully weight the advantages and disadvantages of different register-based definitions according to the individual study’s needs, the time periods involved and the age-groups under study.


Buildings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Ning Gu ◽  
Peiman Amini Behbahani

Computational creativity in built environment (BE) design has been a subject of research interest in the discipline. This paper presents a critical review of various ways computational creativity has been and can be defined and approached in BE design. The paper examines a comprehensive body of contemporary literature on the topics of creativity, computational creativity, and their assessment to identify levels of computational creativity. The paper then proceeds to a further review of the implications of these levels specifically in BE design. The paper identifies four areas in BE design where computational creativity is relevant. In two areas—synthesis (generation) and analysis—there is considerable literature on lower levels of computational creativity. However, in two other areas—interfacing and communication—even the definition of computational creativity is not as defined and clear for the discipline, and most works only consider the role of computers as a supporting tool or medium. These open up future research opportunities for the discipline.


2021 ◽  
Vol 13 (11) ◽  
pp. 5870
Author(s):  
Philipp Kruse

Social Entrepreneurship (SE) describes a new entrepreneurial form combining the generation of financial and social value. In recent years, research interest in SE increased in various disciplines with a particular focus on the characteristics of social enterprises. Whereas a clear-cut definition of SE is yet to be found, there is evidence that culture and economy affect and shape features of SE activity. In addition, sector-dependent differences are supposed. Building on Institutional Theory and employing a mixed qualitative and quantitative approach, this study sheds light on the existence of international and inter-sector differences by examining 161 UK and Indian social enterprises. A content analysis and analyses of variance were employed and yielded similarities as well as several significant differences on an international and inter-sector level, e.g., regarding innovativeness and the generation of revenue. The current study contributes to a more nuanced picture of the SE landscape by comparing social enterprise characteristics in a developed and a developing country on the one hand and different sectors on the other hand. Furthermore, I highlight the benefits of jointly applying qualitative and quantitative methodologies. Future research should pay more attention to the innate heterogeneity among social enterprises and further consolidate and extend these findings.


2019 ◽  
Vol 74 (Suppl. 3) ◽  
pp. 19-24 ◽  
Author(s):  
Daniel R. Westfall ◽  
Nicole E. Logan ◽  
Naiman A. Khan ◽  
Charles H. Hillman

The effects of optimal and insufficient hydration on human health have received increasing investigation in recent years. Specifically, water is an essential nutrient for human health, and the importance of hydration on cognition has continued to attract research interest over the last decade. Despite this focus, children remain a relatively understudied population relative to the effects of hydration on cognition. Of those studies investigating children, findings have been inconsistent, resulting from utilizing a wide variety of cognitive domains and cognitive assessments, as well as varied hydration protocols. Here, our aim is to create a primer for assessing cognition during hydration research in children. Specifically, we review the definition of cognition and the domains of which it is composed, how cognition has been measured in both field- and laboratory-based assessments, results from neuroimaging methods, and the relationship between hydration and academic achievement in children. Lastly, future research considerations are discussed.


2021 ◽  
Vol 13 (11) ◽  
pp. 5956
Author(s):  
Jelena Končar ◽  
Radenko Marić ◽  
Goran Vukmirović ◽  
Sonja Vučenović

This work aims to define the impact of different indicators on the sustainability of food placement in the retail sector, during periods of crisis and emergencies, such as the COVID-19 pandemic. An empirical survey conducted in the Western Balkans (WB) region showed that indicators such as developed infrastructure, consistency, and transparency of the supply chain, skilled workers, costs, food safety, food prices, energy consumption, and changes in consumer needs are statistically significant since they affect the sustainability of food placement in the retail sector. As food placement and the retail sector itself are inseparable from other participants in the food supply chain (FSC), an analysis was conducted at the level of all FSC sectors. The results showed some deviations viewed individually in the sectors of production, physical distribution, wholesale, and retail, and in selected Western Balkan countries. Based on the results obtained, the sustainability model of food placement in the retail sector has been defined. The model will serve as the basis for defining the set of measures and incentives that competent institutions and FSC management need to undertake, to minimize the impact of indicators that endanger sustainability. The originality of the study lies in the fact that it fills the research gap that exists in this subject matter in academic research and studies in the WB region. In addition, some indicators important for food placement have been precisely isolated, with the definition of the intensity of their impact, observed overall at the level of the entire FSC as well as by individual sectors. Guidelines and suggestions for future research are listed in the paper.


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