scholarly journals Predation has small, short-term, and in certain conditions random effects on the evolution of aging

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Peter Lenart ◽  
Julie Bienertová-Vašků ◽  
Luděk Berec
Keyword(s):  
Simulation Model ◽  
Random Effects ◽  
Diet Breadth ◽  
Current Evidence ◽  
Short Term ◽  
Trade Off ◽  
Aging Rate ◽  
Extrinsic Mortality ◽  
Evolution Of Aging ◽  
The Relationship

Abstract Background The pace of aging varies considerably in nature. The best-known explanation of the evolution of specific rates of aging is the Williams’ hypothesis suggesting that the aging rate should correlate with the level of extrinsic mortality. However, the current evidence is inconclusive with various examples where the Williams' hypothesis seems to be correct and where it doesn’t. Here we explore the relationship between extrinsic mortality and aging rate by developing a simulation model of the evolution of aging rate in prey subject to predation. Results Our results suggest that more intense predation leads to the evolution of faster pace of aging in prey. However, this effect slowly vanishes when the predator diet breadth is allowed to evolve, too. Furthermore, in our model, the evolution of a specific aging rate is driven mainly by a single parameter, the strength of a trade-off between aging and fecundity. Indeed, in the absence of this trade-off the evolutionary impacts of predation on the prey aging rate appear random. Conclusions We show that the William’s hypothesis appears valid when there is a trade-off between aging and fecundity and predators and prey do not coevolve. However, we also show that when the prey and predators coevolve or if there is no trade-off between aging and fecundity the William`s hypothesis is no longer applicable.

scholarly journals Predation Has Small, Short-Term, and in Certain Conditions Random Effect on the Evolution of Aging

2020 ◽  
Author(s):  
Peter Lenart ◽  
Julie Bienertová-Vašků ◽  
Luděk Berec
Keyword(s):  
Diet Composition ◽  
Random Effect ◽  
Agent Based Model ◽  
Short Term ◽  
Aging Research ◽  
Trade Off ◽  
Agent Based ◽  
Aging Rate ◽  
Predator Diet ◽  
Evolution Of Aging

AbstractThe pace of aging varies considerably in nature. Historically, scientists focused mostly on why and how has aging evolved, while only a few studies explored mechanisms driving evolution of specific rates of aging. Here we develop an agent-based model simulating evolution of aging in prey subject to predation. Our results suggest that predation affects the pace of aging in prey only if young, vivid animals are not much more likely to escape predators than the old ones. However, even this effect slowly vanishes when the predator diet composition evolves, too. Furthermore, evolution of a specific aging rate, in our model, is driven mainly by a single parameter, the strength of a trade-off between aging and fecundity. Indeed, in absence of this trade-off the evolutionary impacts of predation on the prey aging rate appear random. Our model produces several testable predictions which may be useful for other areas of aging research.

scholarly journals Specificity of Future Thinking in Depression: A Meta-Analysis

2018 ◽  
Author(s):  
Beau Gamble ◽  
David Moreau ◽  
Lynette J. Tippett ◽  
Donna Rose Addis
Keyword(s):  
Random Effects ◽  
Meta Analysis ◽  
Emotional Valence ◽  
Effect Sizes ◽  
Current Evidence ◽  
Future Research ◽  
Future Thinking ◽  
Moderator Variables ◽  
Search Terms ◽  
The Relationship

Reduced specificity of autobiographical memory has been well established in depression, but whether this ‘overgenerality’ extends to future thinking has not been the focus of a meta-analysis. Following a preregistered protocol, we searched six electronic databases, Google Scholar, personal libraries, and contacted authors in the field for studies matching search terms related to depression, future thinking, and specificity. We reduced an initial 7,332 results to 46 included studies, with 89 effect sizes and 4,813 total participants. Random effects meta-analytic modelling revealed a small but robust correlation between reduced future specificity and higher levels of depression (r = .13, p < .001). Of the 11 moderator variables examined, the most striking effects related to the emotional valence of future thinking (p < .001) and the sex of participants (p = .025). Namely, depression was linked to reduced specificity for positive (but not negative or neutral) future thinking, and the relationship was stronger in samples with a higher proportion of males. This meta-analysis contributes to our understanding of how prospection is altered in depression and dysphoria and, by revealing areas where current evidence is inconclusive, highlights key avenues for future research.

scholarly journals Specificity of Future Thinking in Depression: A Meta-Analysis

2019 ◽  
Vol 14 (5) ◽  
pp. 816-834 ◽  
Author(s):  
Beau Gamble ◽  
David Moreau ◽  
Lynette J. Tippett ◽  
Donna Rose Addis
Keyword(s):  
Random Effects ◽  
Meta Analysis ◽  
Emotional Valence ◽  
Effect Sizes ◽  
Current Evidence ◽  
Future Research ◽  
Future Thinking ◽  
Moderator Variables ◽  
Search Terms ◽  
The Relationship

Reduced specificity of autobiographical memory has been well established in depression, but whether this overgenerality extends to future thinking has not been the focus of a meta-analysis. Following a preregistered protocol, we searched six electronic databases, Google Scholar, and personal libraries and contacted authors in the field for studies matching search terms related to depression, future thinking, and specificity. We reduced an initial 7,332 results to 46 included studies, with 89 effect sizes and 4,813 total participants. Random-effects meta-analytic modeling revealed a small but robust correlation between reduced future specificity and higher levels of depression ( r = −.13, p < .001). Of the 11 moderator variables examined, the most striking effects were related to the emotional valence of future thinking ( p < .001) and the sex of participants ( p = .025). Namely, depression was linked to reduced specificity for positive (but not negative or neutral) future thinking, and the relationship was stronger in samples with a higher proportion of males. This meta-analysis contributes to our understanding of how prospection is altered in depression and dysphoria and, by revealing areas where current evidence is inconclusive, highlights key avenues for future research.

scholarly journals Temporal discounting correlates with directed exploration but not with random exploration

2019 ◽  
Author(s):  
Hashem Sadeghiyeh ◽  
Siyu Wang ◽  
Maxwell R. Alberhasky ◽  
Hannah M. Kyllo ◽  
Amitai Shenhav ◽  
...  
Keyword(s):  
Information Seeking ◽  
Temporal Discounting ◽  
Clear Correlation ◽  
Behavioral Variability ◽  
Short Term ◽  
Trade Off ◽  
Multiple Factors ◽  
Tight Connection ◽  
Short Time ◽  
The Relationship

AbstractThe explore-exploit dilemma describes the trade off that occurs any time we must choose between exploring unknown options and exploiting options we know well. Implicit in this trade off is how we value future rewards — exploiting is usually better in the short term, but in the longer term the benefits of exploration can be huge. Thus, in theory there should be a tight connection between how much people value future rewards, i.e. how much they discount future rewards relative to immediate rewards, and how likely they are to explore, with less ‘temporal discounting’ associated with more exploration. By measuring individual differences in temporal discounting and correlating them with explore-exploit behavior, we tested whether this theoretical prediction holds in practice. We used the 27-item Delay-Discounting Questionnaire to estimate temporal discounting and the Horizon Task to quantify two strategies of explore-exploit behavior: directed exploration, where information drives exploration by choice, and random exploration, where behavioral variability drives exploration by chance. We find a clear correlation between temporal discounting and directed exploration, with more temporal discounting leading to less directed exploration. Conversely, we find no relationship between temporal discounting and random exploration. Unexpectedly, we find that the relationship with directed exploration appears to be driven by a correlation between temporal discounting and uncertainty seeking at short time horizons, rather than information seeking at long horizons. Taken together our results suggest a nuanced relationship between temporal discounting and explore-exploit behavior that may be mediated by multiple factors.

scholarly journals Evaluating Factors Affecting the Time Interval Between Propofol Injection and Induction of Electro-convulsion and Relationship Between These Factors and Duration of Convulsion

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Alireza Haji Seyed Javadi ◽  
Ehsan Najafian ◽  
Hamid Kayalha ◽  
Ali Akbar Shafikhani
Keyword(s):  
Clinical Severity ◽  
Seizure Threshold ◽  
Current Evidence ◽  
P Value ◽  
Time Interval ◽  
Short Term ◽  
Seizure Duration ◽  
Factors Affecting ◽  
The Relationship

Background: Current evidence on the effect of anesthetic-ECT time interval (AETI) is controversial. This study aimed to investigate the factors affecting the time interval between propofol injection and electro-convulsion induction and the relationship between these factors and the duration of convulsion. Methods: In this study, 102 patients (616 sessions of ECT) were studied. Demographic and clinical data (age, gender, receiving or not receiving medications that affected the seizure threshold, the total number of ECT sessions, clinical severity of admission scores, clinical diagnosis, propofol dose, seizure duration, and AETI) were collected in special forms and analyzed by appropriate statistical methods. Results: Sessions with long-term AETI had longer seizure time than sessions with short-term AETI (33.47 ± 8.46 vs. 28.68 ± 9.74, P value < 0.05). The duration of seizures was significantly longer in the group with long AETI in sessions 1, 2, and 4 than in the other group (P value < 0.05). There was a significant relationship between the duration of seizures and propofol dose, AETI, and receiving drugs effective in the seizure threshold (P value < 0.05). Conclusions: The results showed that increasing AETI and injecting a lower dose of propofol to induce anesthesia would increase the duration of seizures. Also, taking medications that would affect the seizure threshold reduces the duration of seizures.

The role of national culture in the relationship between microfinance outreach and sustainability: a correlated random effects approach

2020 ◽  
Vol 27 (3) ◽  
pp. 447-472 ◽  
Author(s):  
Mohammad Zainuddin ◽  
Masnun Mahi ◽  
Shabiha Akter ◽  
Ida Md. Yasin
Keyword(s):  
National Culture ◽  
Random Effects ◽  
Information Exchange ◽  
Fixed Effects ◽  
Microfinance Institutions ◽  
Trade Off ◽  
Content Type ◽  
Correlated Random Effects ◽  
The Relationship

PurposeThis study investigates the role of national culture between outreach and sustainability of microfinance institutions (MFIs). Despite microfinance's deep embeddedness in cultural contexts, research on the influence of national culture on MFI performance is rather sparse. This paper seeks to fill this gap and, based on cross-country microfinance data, attempts to explain the outreach-sustainability relationship in reference to cultural factors.Design/methodology/approachAn unbalanced panel, consisting of 5,741 MFI-year observations of 1,232 MFIs from 43 countries in six regions, is drawn from the Microfinance Information Exchange (MIX) Market database. Two different econometric models are tested. Model 1 estimates the direct effect of outreach on sustainability, using a fixed-effects estimator. Model 2 examines the moderation effect of national culture on outreach-sustainability relationship, employing correlated random effects approach.FindingsThe results show that depth of outreach and financial sustainability of MFIs are negatively related, and the relationship is moderated by national culture. Power distance and uncertainty avoidance positively moderate the outreach-sustainability relationship, whereas individualism and masculinity negatively moderate the relationship.Originality/valueThe findings suggest that the national culture where MFIs are located plays an important contingent role in their performance and that the magnitude of the trade-off effect varies from culture to culture. The research thus provides further insight in the trade-off debate and contributes to literatures of both microfinance and cross-cultural management.

scholarly journals Labor Productivity and Phillips Curve in China: Contemporary Investigation

2019 ◽  
Vol 15 (1) ◽  
pp. 37-48
Author(s):  
Nahid Kalbasi Anaraki
Keyword(s):  
Monetary Policy ◽  
Exchange Rate ◽  
Phillips Curve ◽  
Short Term ◽  
Trade Off ◽  
The United Kingdom ◽  
Long Run ◽  
Advanced Economies ◽  
Using Data ◽  
The Relationship

The Phillips curve on the trade-off between inflation and unemployment has been debated among economists for more than decades. Several studies have found that Phillips curve is dead in advanced economies and does not exist. Among others, Friedman (1968) stated that Phillips curve does not exist in the long-run because the relationship between inflation and unemployment is a temporary and short-term. On the contrary, Fuhrer (1995) found that Phillips curve is still alive in the United Kingdom; and Malinov and Sommers (1997) found that Phillips curve is still alive and stable in several OECD countries. This paper attempts to investigate whether a long-run Philips Curve exists in China. Using data for the period of 1987-2016 the estimated results of this study indicate that the Phillips curve, which existed during the late 1980s through 2000 in China has been gradually transformed to an almost vertical curve since 2000s, with a correlation of 0.8, indicating the importance of other policy variables including monetary policy and exchange rate regimes.

COVID-19 in children: Pathogenesis and current status

2020 ◽  
Author(s):  
Lawrence Frenkel ◽  
Fernando Gomez ◽  
Joseph A Bellanti
Keyword(s):  
Respiratory Disease ◽  
Respiratory Symptoms ◽  
Distress Syndrome ◽  
Clinical Course ◽  
Current Status ◽  
Current Evidence ◽  
Initial Description ◽  
Relationship Of ◽  
Inflammatory Syndrome ◽  
The Relationship

Background: Since its initial description in December 2019 in Wuhan, China, coronavirus disease 2019 (COVID-19) has rapidly progressed into a worldwide pandemic, which has affected millions of lives. Unlike the disease in adults, the vast majority of children with COVID-19 have mild symptoms and are largely spared from severe respiratory disease. However, thereare children who have significant respiratory disease, and some may develop a hyperinflammatory response similar to thatseen in adults with COVID-19 and in children with Kawasaki disease (KD), which has been termed multisystem inflammatory syndrome in children (MIS-C).Objective: The purpose of this report was to examine the current evidence that supports the etiopathogenesis of COVID-19 in children and the relationship of COVID-19 with KD and MIS-C as a basis for a better understanding of the clinical course, diagnosis, and management of these clinically perplexing conditions.Results: The pathogenesis of COVID-19 is carried out in two distinct but overlapping phases of COVID-19: the first triggered by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) itself and the second by the host immune response. Children with KD have fewer of the previously described COVID-19–associated KD features with less prominent acute respiratory distress syndrome and shock than children with MIS-C.Conclusion: COVID-19 in adults usually includes severe respiratory symptoms and pathology, with a high mortality. Ithas become apparent that children are infected as easily as adults but are more often asymptomatic and have milder diseasebecause of their immature immune systems. Although children are largely spared from severe respiratory disease, they canpresent with a SARS-CoV-2–associated MIS-C similar to KD.

Evaluation of the Efficacy of ST2 and NT-proBNP in the Diagnosis and Prediction of Short- Term Prognosis in Heart Failure with Reduced Ejection Fraction

2017 ◽  
Vol 9 (04) ◽  
Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Biomarkers ◽  
Double Blind Study ◽  
Short Term ◽  
Double Blind ◽  
Reduced Ejection Fraction ◽  
The Mean ◽  
Design And Methods ◽  
The Relationship

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.

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