scholarly journals Generalized Counting Processes in a Stochastic Environment

Mathematics ◽  
2021 ◽  
Vol 9 (20) ◽  
pp. 2573
Author(s):  
Davide Cocco ◽  
Massimiliano Giona

This paper addresses the generalization of counting processes through the age formalism of Lévy Walks. Simple counting processes are introduced and their properties are analyzed: Poisson processes or fractional Poisson processes can be recovered as particular cases. The stationarity assumption in the renewal mechanism characterizing simple counting processes can be modified in different ways, leading to the definition of generalized counting processes. In the case that the transition mechanism of a counting process depends on the environmental conditions—i.e., the parameters describing the occurrence of new events are themselves stochastic processes—the counting processes is said to be influenced by environmental stochasticity. The properties of this class of processes are analyzed, providing several examples and applications and showing the occurrence of new phenomena related to the modulation of the long-term scaling exponent by environmental noise.

2009 ◽  
Vol 2009 ◽  
pp. 1-43 ◽  
Author(s):  
Ushio Sumita ◽  
Jia-Ping Huang

The class of counting processes constitutes a significant part of applied probability. The classic counting processes include Poisson processes, nonhomogeneous Poisson processes, and renewal processes. More sophisticated counting processes, including Markov renewal processes, Markov modulated Poisson processes, age-dependent counting processes, and the like, have been developed for accommodating a wider range of applications. These counting processes seem to be quite different on the surface, forcing one to understand each of them separately. The purpose of this paper is to develop a unified multivariate counting process, enabling one to express all of the above examples using its components, and to introduce new counting processes. The dynamic behavior of the unified multivariate counting process is analyzed, and its asymptotic behavior ast→∞is established. As an application, a manufacturing system with certain maintenance policies is considered, where the optimal maintenance policy for minimizing the total cost is obtained numerically.


2014 ◽  
Vol 76 ◽  
pp. 15-23
Author(s):  
Barrie J. Wills

A warm welcome to our "World of Difference" to all delegates attending this conference - we hope your stay is enjoyable and that you will leave Central Otago with an enhanced appreciation of the diversity of land use and the resilient and growing economic potential that this region has to offer. Without regional wellbeing the national economy will struggle to grow, something Central Government finally seems to be realising, and the Central Otago District Council Long Term Plan 2012-2022 (LTP) signals the importance of establishing a productive economy for the local community which will aid in the economic growth of the district and seeks to create a thriving economy that will be attractive to business and residents alike. Two key principles that underpin the LTP are sustainability and affordability, with the definition of sustainability being "… development that meets the needs of the present without compromising the ability of future generations to meet their own needs."


Author(s):  
Takis S. Pappas

Based on an original definition of modern populism as “democratic illiberalism” and many years of meticulous research, Takis Pappas marshals extraordinary empirical evidence from Argentina, Greece, Peru, Italy, Venezuela, Ecuador, Hungary, the United States, Spain, and Brazil to develop a comprehensive theory about populism. He addresses all key issues in the debate about populism and answers significant questions of great relevance for today’s liberal democracy, including: • What is modern populism and how can it be differentiated from comparable phenomena like nativism and autocracy? • Where in Latin America has populism become most successful? Where in Europe did it emerge first? Why did its rise to power in the United States come so late? • Is Trump a populist and, if so, could he be compared best with Venezuela’s Chávez, France’s Le Pens, or Turkey’s Erdoğan? • Why has populism thrived in post-authoritarian Greece but not in Spain? And why in Argentina and not in Brazil? • Can populism ever succeed without a charismatic leader? If not, what does leadership tell us about how to challenge populism? • Who are “the people” who vote for populist parties, how are these “made” into a group, and what is in their minds? • Is there a “populist blueprint” that all populists use when in power? And what are the long-term consequences of populist rule? • What does the expansion, and possibly solidification, of populism mean for the very nature and future of contemporary democracy? Populism and Liberal Democracy will change the ways the reader understands populism and imagines the prospects of liberal democracy.


Author(s):  
Katharina Diehl ◽  
Tatiana Görig ◽  
Charlotte Jansen ◽  
Maike Carola Hruby ◽  
Annette B. Pfahlberg ◽  
...  

Pharmacists and pharmaceutical technicians play an important role in counselling customers regarding sunscreen use and sun protection measures. A potentially helpful tool that can be used during counselling is the ultraviolet index (UVI), which informs individuals when and what sun protection measures are needed at a specific place and time. Our aim in this qualitative study was to explore awareness, knowledge, and use of the UVI during counselling in pharmacies. We used semi-structured interviews with pharmacists and pharmaceutical technicians (n = 20) to answer our research questions. Interviews were audiotaped, transcribed verbatim, and analyzed using qualitative content analysis. During the interviews pharmacists and pharmaceutical technicians revealed a lot of uncertainty and lack of knowledge regarding the UVI. Eight professionals were able to give a correct definition of UVI. Amongst others, the UVI was confused with sun protection factor. Overall, the UVI was hardly used during the counselling of customers. The UVI was developed to provide guidance when which type of sun protection is required to avoid detrimental effects of ultraviolet radiation. For effective implementation, both the general population and health professionals (e.g., pharmacists) have to increase their knowledge about the UVI. This would strengthen its use during professional counselling in pharmacies and may help to reduce the incidence of skin cancer over the long term.


Author(s):  
Pablo Villalobos Dintrans ◽  
Jorge Browne ◽  
Ignacio Madero-Cabib

Abstract Objective Provide a synthesis of the COVID-19 policies targeting older people in Chile, stressing their short- and long-term challenges. Method Critical analysis of the current legal and policy measures, based on national-level data and international experiences. Results Although several policies have been enacted to protect older people from COVID-19, these measures could have important unintended negative consequences in this group’s mental and physical health, as well as financial aspects. Discussion A wider perspective is needed to include a broader definition of health—considering financial scarcity, access to health services, mental health issues, and long-term care—in the policy responses to COVID-19 targeted to older people in Chile.


2021 ◽  
Vol 8 (1) ◽  
pp. e000563
Author(s):  
Peter Fentz Haastrup ◽  
Dorte Ejg Jarbøl ◽  
Wade Thompson ◽  
Jane Møller Hansen ◽  
Jens Søndergaard ◽  
...  

ObjectiveProton pump inhibitor (PPI) use has risen substantially, primarily driven by ongoing use over months to years. However, there is no consensus on how to define long-term PPI use. Our objectives were to review and compare definitions of long-term PPI use in existing literature and describe the rationale for each definition. Moreover, we aimed to suggest generally applicable definitions for research and clinical use.DesignThe databases PubMed and Cochrane Library were searched for publications concerning long-term use of PPIs and ClinicalTrials.gov was searched for registered studies. Two reviewers independently screened the titles, abstracts, and full texts in two series and subsequently extracted data.ResultsA total of 742 studies were identified, and 59 met the eligibility criteria. In addition, two ongoing studies were identified. The definition of long-term PPI use varied from >2 weeks to >7 years. The most common definition was ≥1 year or ≥6 months. A total of 12/61 (20%) of the studies rationalised their definition.ConclusionThe definitions of long-term PPI treatment varied substantially between studies and were seldom rationalised.In a clinical context, use of PPI for more than 8 weeks could be a reasonable definition of long-term use in patients with reflux symptoms and more than 4 weeks in patients with dyspepsia or peptic ulcer. For research purposes, 6 months could be a possible definition in pharmacoepidemiological studies, whereas studies of adverse effects may require a tailored definition depending on the necessary exposure time. We recommend to always rationalise the choice of definition.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Cecilia Rocchi ◽  
Lara Barazzuol ◽  
Rob P. Coppes

AbstractDysfunction of the salivary gland and irreversible hyposalivation are the main side effects of radiotherapy treatment for head and neck cancer leading to a drastic decrease of the quality of life of the patients. Approaches aimed at regenerating damaged salivary glands have been proposed as means to provide long-term restoration of tissue function in the affected patients. In studies to elucidate salivary gland regenerative mechanisms, more and more evidence suggests that salivary gland stem/progenitor cell behavior, like many other adult tissues, does not follow that of the hard-wired professional stem cells of the hematopoietic system. In this review, we provide evidence showing that several cell types within the salivary gland epithelium can serve as stem/progenitor-like cells. While these cell populations seem to function mostly as lineage-restricted progenitors during homeostasis, we indicate that upon damage specific plasticity mechanisms might be activated to take part in regeneration of the tissue. In light of these insights, we provide an overview of how recent developments in the adult stem cell research field are changing our thinking of the definition of salivary gland stem cells and their potential plasticity upon damage. These new perspectives may have important implications on the development of new therapeutic approaches to rescue radiation-induced hyposalivation.


2021 ◽  
Author(s):  
Kim Martinez ◽  
Maria Isabel Menéndez-Menéndez ◽  
David Checa ◽  
Andres Bustillo

BACKGROUND The design of Virtual Reality Serious Games (VR-SG) is a subject still developing. One of its open developments is the definition of metrics to evaluate the fun and learning result. In this way, weaknesses and strengths in the design of serious games can be found for future works in this research field. OBJECTIVE This paper aims to create a metric that can be used to rate the gameplay of VR-SG. This metric’s novelty allows to evaluate the different fun and learning features and give them a quantitative rating. A study case shows the capability of implementing this evaluation to identify strengths and weaknesses of VR-SGs. METHODS The new VR-SG metric is developed on the basis of the Mechanics, Dynamics and Aesthetic (MDA) framework but including User Experience (UX) elements and adapting them to VR-SG. This metric includes 1) UX aspects: VR-headsets, training tutorials and interactive adaptions to avoid VR inconveniences; and 2) MDA aspects: exclusive VR audiovisual elements and its aesthetics interactions. RESULTS The selected indie serious game is Hellblade, developed to raise awareness about the difficulties of people suffering from psychosis with two versions: one for 2D-screens and the other for VR devices. The comparison of metric´s scores for both versions shows: 1) some VR dynamics increase the gameplay impact and therefore, the educational capacity; and 2) flaws in game design where the scores drop down. Some of these flaws are: reduced number of levels, missions and items, lack of a tutorial to enhance usability and lack of strategies and rewards in the long-term to increase motivation. CONCLUSIONS This metric allows to identify the elements of the gameplay and UX that are necessary to learn in VR experiences. The study case shows this research is useful to evaluate the educational utility of VR-SG. Further works will analyze VR applications to synthetize every game element influencing its intrinsic sensations. CLINICALTRIAL The trials have not been registered, as testing for this metric has not involved people with mental conditions or addressed other medical applications. Hellblade is a commercial video game that anyone can purchase and play. The trials have been carried out to obtain results on the gaming experience of different people in relation to the educational purpose of raising awareness of psychosis.


2002 ◽  
Vol 2 ◽  
pp. 169-189 ◽  
Author(s):  
Lawrence W. Barnthouse ◽  
Douglas G. Heimbuch ◽  
Vaughn C. Anthony ◽  
Ray W. Hilborn ◽  
Ransom A. Myers

We evaluated the impacts of entrainment and impingement at the Salem Generating Station on fish populations and communities in the Delaware Estuary. In the absence of an agreed-upon regulatory definition of “adverse environmental impact” (AEI), we developed three independent benchmarks of AEI based on observed or predicted changes that could threaten the sustainability of a population or the integrity of a community.Our benchmarks of AEI included: (1) disruption of the balanced indigenous community of fish in the vicinity of Salem (the “BIC” analysis); (2) a continued downward trend in the abundance of one or more susceptible fish species (the “Trends” analysis); and (3) occurrence of entrainment/impingement mortality sufficient, in combination with fishing mortality, to jeopardize the future sustainability of one or more populations (the “Stock Jeopardy” analysis).The BIC analysis utilized nearly 30 years of species presence/absence data collected in the immediate vicinity of Salem. The Trends analysis examined three independent data sets that document trends in the abundance of juvenile fish throughout the estuary over the past 20 years. The Stock Jeopardy analysis used two different assessment models to quantify potential long-term impacts of entrainment and impingement on susceptible fish populations. For one of these models, the compensatory capacities of the modeled species were quantified through meta-analysis of spawner-recruit data available for several hundred fish stocks.All three analyses indicated that the fish populations and communities of the Delaware Estuary are healthy and show no evidence of an adverse impact due to Salem. Although the specific models and analyses used at Salem are not applicable to every facility, we believe that a weight of evidence approach that evaluates multiple benchmarks of AEI using both retrospective and predictive methods is the best approach for assessing entrainment and impingement impacts at existing facilities.


1969 ◽  
Vol 115 (518) ◽  
pp. 9-30 ◽  
Author(s):  
Colin Protheroe

There exists a vast literature on the puerperal psychoses. Most of it is incomplete in that rarely is any definition of the “puerperal period” made; frequently there is no attempt to differentiate between the various clinical syndromes seen when aetiology is considered, and little consideration is given to the extent of constitutional predisposition to psychiatric illness in the probands.


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