scholarly journals A Holistic Approach to Study Photosynthetic Acclimation Responses of Plants to Fluctuating Light

2021 ◽  
Vol 12 ◽  
Author(s):  
Armida Gjindali ◽  
Helena A. Herrmann ◽  
Jean-Marc Schwartz ◽  
Giles N. Johnson ◽  
Pablo I. Calzadilla
Keyword(s):  
Mathematical Modeling ◽  
Photosynthetic Apparatus ◽  
Holistic Approach ◽  
Photosynthetic Acclimation ◽  
Natural Environments ◽  
Short Term ◽  
Fluctuating Light ◽  
Photosynthetic Responses ◽  
Over Time

Plants in natural environments receive light through sunflecks, the duration and distribution of these being highly variable across the day. Consequently, plants need to adjust their photosynthetic processes to avoid photoinhibition and maximize yield. Changes in the composition of the photosynthetic apparatus in response to sustained changes in the environment are referred to as photosynthetic acclimation, a process that involves changes in protein content and composition. Considering this definition, acclimation differs from regulation, which involves processes that alter the activity of individual proteins over short-time periods, without changing the abundance of those proteins. The interconnection and overlapping of the short- and long-term photosynthetic responses, which can occur simultaneously or/and sequentially over time, make the study of long-term acclimation to fluctuating light in plants challenging. In this review we identify short-term responses of plants to fluctuating light that could act as sensors and signals for acclimation responses, with the aim of understanding how plants integrate environmental fluctuations over time and tailor their responses accordingly. Mathematical modeling has the potential to integrate physiological processes over different timescales and to help disentangle short-term regulatory responses from long-term acclimation responses. We review existing mathematical modeling techniques for studying photosynthetic responses to fluctuating light and propose new methods for addressing the topic from a holistic point of view.

The Short-Term and Long-Term Impacts of Sarbanes-Oxley Act on Composition and Characteristics of Corporate Board of Directors

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Halil Kaya ◽  
Gaurango Banerjee
Keyword(s):  
Board Composition ◽  
Corporate Boards ◽  
Corporate Accountability ◽  
Corporate Board ◽  
Short Term ◽  
Dual Roles ◽  
Board Characteristics ◽  
Sarbanes Oxley ◽  
Over Time

The paper examines the Sarbanes-Oxley (2002) Acts immediate impact on board composition and characteristics as well as possible reversals in its impact over time. Effects on directors age and tenure are analyzed over the 2001-06 sample period. Female participation in corporate boards is also studied in the pre-SOX and post-SOX periods. The dual roles of directors in being a member of the board as well as serving as either CEO, CFO, Chairman, Co-Chair, Founder, or Lead Director of their respective companies is also examined. We observe a short-term impact of SOX on board compositions due to changes seen in board characteristics between 2001 (pre-SOX), and 2003-05 short-term period (post-SOX). Also, we observe a reversal of board characteristics in 2006 to pre-SOX levels implying that the effects of SOX on board composition were short-lived, and needs to be monitored over time to ensure adherence to corporate accountability guidelines over the long-term.

scholarly journals Personality dynamics at work: The effects of form, time, and context of variability

2021 ◽  
pp. 089020702110173
Author(s):  
Nadin Beckmann ◽  
Damian P Birney ◽  
Amirali Minbashian ◽  
Jens F Beckmann
Keyword(s):  
Individual Differences ◽  
Cognitive Ability ◽  
Temporal Stability ◽  
Limited Evidence ◽  
Short Term ◽  
State Data ◽  
The Status ◽  
Over Time ◽  
Trait Variability

The study aimed to investigate the status of within-person state variability in neuroticism and conscientiousness as individual differences constructs by exploring their (a) temporal stability, (b) cross-context consistency, (c) empirical links to selected antecedents, and (d) empirical links to longer term trait variability. Employing a sample of professionals ( N = 346) from Australian organisations, personality state data together with situation appraisals were collected using experience sampling methodology in field and repeatedly in lab-like settings. Data on personality traits, cognitive ability, and motivational mindsets were collected at baseline and after two years. Contingent (situation contingencies) and non-contingent (relative SD) state variability indices were relatively stable over time and across contexts. Only a small number of predictive effects of state variability were observed, and these differed across contexts. Cognitive ability appeared to be associated with state variability under lab-like conditions. There was limited evidence of links between short-term state and long-term trait variability, except for a small effect for neuroticism. Some evidence of positive manifold was found for non-contingent variability. Systematic efforts are required to further elucidate the complex pattern of results regarding the antecedents, correlates and outcomes of individual differences in state variability.

scholarly journals Investigating the Broken-Heart Effect: a Model for Short-Term Dependence between the Remaining Lifetimes of Joint Lives

2012 ◽  
Vol 7 (2) ◽  
pp. 236-257 ◽  
Author(s):  
Jaap Spreeuw ◽  
Iqbal Owadally
Keyword(s):  
Mortality Rates ◽  
Short Term ◽  
Numerical Work ◽  
Data Set ◽  
Multiple State ◽  
Multiple State Model ◽  
Insurance Data ◽  
Over Time ◽  
Assurance Contracts

AbstractWe analyze the mortality of couples by fitting a multiple state model to a large insurance data set. We find evidence that mortality rates increase after the death of a partner and, in addition, that this phenomenon diminishes over time. This is popularly known as a “broken-heart” effect and we find that it affects widowers more than widows. Remaining lifetimes of joint lives therefore exhibit short-term dependence. We carry out numerical work involving the pricing and valuation of typical contingent assurance contracts and of a joint life and survivor annuity. If insurers ignore dependence, or mis-specify it as long-term dependence, then significant mis-pricing and inappropriate provisioning can result. Detailed numerical results are presented.

scholarly journals Macroeconomic Synchronization Between G3 Countries

2002 ◽  
Vol 3 (2) ◽  
pp. 137-153 ◽  
Author(s):  
Amado Peirό
Keyword(s):  
Business Cycle ◽  
Interest Rates ◽  
Short Term ◽  
The Us ◽  
Production Prices ◽  
Over Time

AbstractThis paper studies the existence of a world business cycle by examining quarterly and annual comovements in production, prices and interest rates in the three main world economies: Germany, Japan and the US. In accordance with earlier studies, contemporaneous relationships clearly dominate short-term dynamics. The evidence indicates the existence of strong comovements in prices and long-term interest rates, and, to a lesser degree, in GDP and short-term interest rates. They are, however, rather unstable over time.

scholarly journals Disentangling niche theory and beta diversity change

2021 ◽  
Author(s):  
William Godsoe ◽  
Peter J Bellingham ◽  
Elena Moltchanova
Keyword(s):  
Beta Diversity ◽  
Price Equation ◽  
Short Term ◽  
Before And After ◽  
Environmental Requirements ◽  
Habitat Specialists ◽  
Montane Tropical Forest ◽  
Ecological Drift ◽  
Over Time

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favours habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e. its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

A Checklist for a New Millennium School Science Department

2011 ◽  
pp. 273-274
Author(s):  
Ed Hessler
Keyword(s):  
Professional Development ◽  
Teacher Preparation ◽  
Student Learning ◽  
School Science ◽  
Learning Science ◽  
Science Department ◽  
Short Term ◽  
Over Time ◽  
New Millennium

My focus is both narrow and incomplete, for it is limited to a single area of learning: science, and it is in the form of a working list, a beginning of things one might write down, not in any particular order—so that they might be remembered and edited over time, with colleagues. Improving schools, teacher preparation, and professional development are important national priorities as we enter a new millennium. Past emphasis on targeted innovations in the short term are now conceptualized into the idea of continuous improvements that are connected in the long term. Today, the idea of improvement itself is being challenged. “Improvement,” the term of the technocrat, is being recast in the context of student learning—that is, how can we educate our young or learners of any age?

A Framework for the Interaction of Active Audiences and Influencers on Twitter: The Case of Zika Virus

2020 ◽  
Vol 19 (04) ◽  
pp. 2050032
Author(s):  
Shadi Shakeri
Keyword(s):  
Agenda Setting ◽  
Crisis Communication ◽  
Explicit Knowledge ◽  
User Involvement ◽  
Short Term ◽  
Health Crisis ◽  
Network Community ◽  
Twitter Users ◽  
Over Time

In this paper, we investigate communication among Twitter users in the context of the 2016 Zika crisis, to understand how influencers and audiences contribute to agenda setting in health crisis communication. We analyse the content of 146,953 Zika-related tweets posted between April and September 2016 and examine how discussion topics vary by network community and user involvement over time. We argue that audiences adopt a broad view of health crisis-related issues and advocate for long-term solutions drawn from theories of active audiences and agenda-setting. Based on our observations on the Zika crisis case, we propose a framework for the dynamics in health crisis communication, which suggests a shift of discourse from a short-term perspective on specific issues to a long-term perspective on broader issues. The research contributes to the KM literature by suggesting a new method for converting individual tacit knowledge to collective explicit knowledge. Applying the framework to the coronavirus pandemic conversations can offer significant insights into the crisis.

Aging Couples: Benefits and Costs of Long Intimate Relations

2018 ◽  
Author(s):  
Victoria I. Michalowski ◽  
Denis Gerstorf ◽  
Christiane A. Hoppmann
Keyword(s):  
Time Frame ◽  
Multiple Time Scales ◽  
Future Research ◽  
Multiple Time ◽  
Physical And Mental Health ◽  
Short Term ◽  
Intimate Relations ◽  
Benefits And Costs ◽  
Over Time

Aging does not occur in isolation, but often involves significant others such as spouses. Whether such dyadic associations involve gains or losses depends on a myriad of factors, including the time frame under consideration. What is beneficial in the short term may not be so in the long term, and vice versa. Similarly, what is beneficial for one partner may be costly for the other, or the couple unit over time. Daily dynamics between partners involving emotion processes, health behaviors, and collaborative cognition may accumulate over years to affect the longer-term physical and mental health outcomes of either partner or both partners across adulthood and into old age. Future research should move beyond an individual-focused approach to aging and consider the importance of and interactions among multiple time scales to better understand how, when, and why older spouses shape each other’s aging trajectories, both for better and for worse.

N-Acetylcysteine’s Attenuation of Fatigue After Repeated Bouts of Intermittent Exercise: Practical Implications for Tournament Situations

2011 ◽  
Vol 21 (6) ◽  
pp. 451-461 ◽  
Author(s):  
James N. Cobley ◽  
Chris McGlory ◽  
James P. Morton ◽  
Graeme L. Close
Keyword(s):  
Side Effects ◽  
Muscle Fatigue ◽  
Intermittent Exercise ◽  
Adaptive Responses ◽  
Short Term ◽  
Treatment Dose ◽  
Gastrointestinal Side Effects ◽  
Matched Design ◽  
Over Time

Production of reactive oxygen species (ROS) during muscle contractions is associated with muscle fatigue and damage in the short term and adaptive responses in the long term. When adaptation is inconsequential acute antioxidant supplementation may be able to attenuate muscle fatigue and damage to enhance performance. This study aimed to determine the effects of acute oral N-acetylcysteine (NAC) supplementation on Yo-Yo Intermittent Recovery Test Level 1 (YIRT-L1) performance after repeated bouts of damaging intermittent exercise. In a pair-matched design, 12 recreationally trained men engaged in 6 d of either NAC (n = 6) or placebo (n = 6) supplementation. After a treatment-loading day, participants completed 3 testing sessions, on alternating days, consisting of a preexercise isokinetic dynamometry (IKD) test, a damaging intermittent-exercise protocol, YIRT-L1, and a postexercise IKD test. Another IKD test was completed on the 2 intervening d. NAC treatment resulted in a significant preservation of YIRT-L1 performance (p ≤ .0005). IKD performance significantly deteriorated over time at all contraction speeds, and this deterioration was not influenced by treatment group. Plasma creatine kinase values increased significantly over time (p = .002) and were significantly greater in the NAC group than in the placebo group (p = .029). NAC induced mild gastrointestinal side effects. NAC supplementation may be a useful strategy to enhance performance during short-term competitive situations when adaption is inconsequential. Titration studies to elucidate a treatment dose that enhances performance without inducing side effects are now required.

Growing without Pains? Explaining Liberal Democrat MPs' Behaviour

2009 ◽  
Vol 11 (2) ◽  
pp. 259-279 ◽  
Author(s):  
Matt Cole
Keyword(s):  
Group Composition ◽  
National Party ◽  
Short Term ◽  
Contextual Data ◽  
Liberal Democrats ◽  
Composition Structure ◽  
High Level ◽  
Over Time

Recent academic studies and wider commentary on the behaviour of Liberal Democrat MPs have recognised their relatively high level of cohesiveness on whipped votes when compared to that of Labour and the Conservatives, and to the Liberal Democrats' own reputation; but while this trend continues, few studies have focused upon its causes. This article uses the MPs' voting records, personal papers, interviews and wider contextual data to chart the extent of that unity over time, and to explore its origins, including group composition, structure, patronage, relations with the extra-parliamentary party and other parties as well as national party image. It finds the key to this unity in a combination of medium and long-term features of the Liberal and Liberal Democrat group of MPs, rather than a short-term singular determinant.

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