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.

scholarly journals Can we always trust rhinomanometry?

2011 ◽  
Vol 49 (1) ◽  
pp. 46-52
Author(s):  
Helle L. Thulesius ◽  
Anders Cervin ◽  
Max Jessen
Keyword(s):  
Nasal Cavity ◽  
Future Research ◽  
Nasal Airway ◽  
Nasal Surgery ◽  
Short Term ◽  
Nasal Stuffiness ◽  
Before And After ◽  
Over Time ◽  
Active Anterior Rhinomanometry

Objectives: Rhinomanometry before and after decongestion distinguishes a nasal airway organic stenosis from congestion of nasal mucosa in patients with nasal stuffiness. Together with rhinoscopy and patient history, it is used to decide if nasal surgery would benefit the patient. Rhinomanometry measurements should thus be reliable and reproducible. Materials and methods: We performed repetitive active anterior rhinomanometry in 9 persons during 5 months to test reproducibility of nasal airway resistance (NAR) over time. We also did test-retest measurements in several participants. Xylometazoline hydrochloride was applied in each nasal cavity to minimize effects of mucosal variation and the nasal cavity was examined with rhinoscopy. The participants evaluated subjective nasal stuffiness on a visual analogue scale (VAS). Results: The long term mean coefficient of variation (CV) of NAR over time was 27% for the whole group while the short term CV was 7 - 17% for test-retest within an hour. Mean NAR reduction after decongestion was 33%, but 13% of NAR values were not reduced after decongestion. Participants had difficulties estimating stuffiness on a VAS in 15% of the assessments, but there was no correlation between the VAS estimates and NAR. Conclusion: We found a high NAR variation over a period of five months. This implies low long-term rhinomanometry reproducibility and we suggest future research on standardised decongestion to increase the reproducibility.

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 Feasibility and Enjoyment of Exercise Video Games in Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 559-559
Author(s):  
Sara Freed ◽  
Briana Sprague ◽  
Lesley Ross
Keyword(s):  
Older Adults ◽  
Video Games ◽  
Game Design ◽  
Long Term Effects ◽  
Short Term ◽  
Qualitative And Quantitative ◽  
Before And After ◽  
Xbox Kinect ◽  
Game Developers

Abstract Interventions using exercise video games, or exergames, have shown short-term cognitive and physical benefits to older adults, though long-term effects are less promising. Enjoyment of exergames may promote exergame use after the intervention period, though little work has examined older adults’ views of exergames before and after gameplay experience. We invited 20 older adults between 65 and 84 years of age (M=73.30, SD=5.95) to play two Xbox Kinect games, Just Dance and Kinect Sports Rivals, for twenty minutes. In our presentation, we will present qualitative and quantitative findings of this pilot study, including findings that older adults reported that they were not likely to play similar exergames in the future and that they did not find the exergames to be more fun compared to other ways of exercising. We will discuss implications for game design and research relevant to game developers, manufacturers, and researchers. Part of a symposium sponsored by Technology and Aging Interest Group.

scholarly journals Endoscopically controlled surgery with open hemilaminectomy for the treatment of intradural extramedullary tumors: an operative technique and short-term outcomes of 20 consecutive cases

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaorong Yan ◽  
Huiqing Wang ◽  
Cai Li ◽  
Yuanxiang Lin ◽  
Lin Lin ◽  
...  
Keyword(s):  
Surgical Technique ◽  
Spinal Deformity ◽  
Tumor Recurrence ◽  
Clinical Symptoms ◽  
Short Term ◽  
Before And After ◽  
Intradural Extramedullary ◽  
Controlled Surgery

Abstract Background To present a surgical technique for the treatment of intradural extramedullary (IDEM) tumors by using endoscopically controlled surgery with open hemilaminectomy technique. Methods In this study, 20 patients with 22 IDEM tumors were enrolled. An endoscopically controlled surgery with open hemilaminectomy was employed to remove the tumors. Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis. Results All the tumors in 20 patients were well removed. The clinical symptoms were significantly reduced in all the patients as well. The short-term follow-up data showed that there was no tumor recurrence or spinal deformity. Conclusion The endoscopically controlled surgery with open hemilaminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors. It may be an effective surgical method for treating IDEM tumors. Larger samples and longer follow-up data are needed to verify its long-term effectiveness.

MULTIFRACTAL FLUCTUATIONS OF JIUZHAIGOU TOURISTS BEFORE AND AFTER WENCHUAN EARTHQUAKE

Fractals ◽  
2013 ◽  
Vol 21 (01) ◽  
pp. 1350001 ◽  
Author(s):  
KAI SHI ◽  
WEN-YONG LI ◽  
CHUN-QIONG LIU ◽  
ZHENG-WEN HUANG
Keyword(s):  
Wenchuan Earthquake ◽  
Moving Average ◽  
Long Term Memory ◽  
Short Term ◽  
Dynamical Mechanism ◽  
Before And After ◽  
Previous State ◽  
Multifractal Behavior ◽  
Multifractal Nature

In this work, multifractal methods have been successfully used to characterize the temporal fluctuations of daily Jiuzhai Valley domestic and foreign tourists before and after Wenchuan earthquake in China. We used multifractal detrending moving average method (MF-DMA). It showed that Jiuzhai Valley tourism markets are characterized by long-term memory and multifractal nature in. Moreover, the major sources of multifractality are studied. Based on the concept of sliding window, the time evolutions of the multifractal behavior of domestic and foreign tourists were analyzed and the influence of Wenchuan earthquake on Jiuzhai Valley tourism system dynamics were evaluated quantitatively. The study indicates that the inherent dynamical mechanism of Jiuzhai Valley tourism system has not been fundamentally changed from long views, although Jiuzhai Valley tourism system was seriously affected by the Wenchuan earthquake. Jiuzhai Valley tourism system has the ability to restore to its previous state in the short term.

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 Endoscopically-controlled surgery with open hemi-laminectomy for the treatment of intradural extramedullary tumors: An operative technique and short-term outcomes of 20 consecutive cases

2020 ◽  
Author(s):  
Xiaorong Yan ◽  
Huiqing Wang ◽  
Cai Li ◽  
Yuanxiang Lin ◽  
Lin Lin ◽  
...  
Keyword(s):  
Surgical Technique ◽  
Spinal Deformity ◽  
Tumor Recurrence ◽  
Clinical Symptoms ◽  
Short Term ◽  
Before And After ◽  
Intradural Extramedullary ◽  
Controlled Surgery

Abstract Background To present a surgical technique for the treatment of intradural extramedullary (IDEM) tumors by using endoscopically-controlled surgery with open hemi-laminectomy technique. Methods In this study, 20 patients with 22 IDEM tumors were enrolled. An endoscopically-controlled surgery with open hemi-laminectomy was employed to remove the tumors. Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis. Results All the tumors in 20 patients were well removed. The clinical symptoms were significantly reduced in all the patients as well. The short term follow-up data showed that there was no tumor recurrence or spinal deformity. Conclusion The endoscopically-controlled surgery with open hemi-laminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors. It may be an effective surgical method for treating IDEM tumors. Larger samples and longer follow-up data are needed to verify its long-term effectiveness.

scholarly journals Predicting the cumulative medical load of COVID-19 outbreaks after the peak in daily fatalities

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0247272
Author(s):  
Claudius Gros ◽  
Roser Valenti ◽  
Lukas Schneider ◽  
Benedikt Gutsche ◽  
Dimitrije Marković
Keyword(s):  
Phase Space ◽  
Sir Model ◽  
Reaction Model ◽  
Space Representation ◽  
Cumulative Number ◽  
Short Term ◽  
Before And After ◽  
The Status ◽  
Short And Long Term

The distinct ways the COVID-19 pandemic has been unfolding in different countries and regions suggest that local societal and governmental structures play an important role not only for the baseline infection rate, but also for short and long-term reactions to the outbreak. We propose to investigate the question of how societies as a whole, and governments in particular, modulate the dynamics of a novel epidemic using a generalization of the SIR model, the reactive SIR (short-term and long-term reaction) model. We posit that containment measures are equivalent to a feedback between the status of the outbreak and the reproduction factor. Short-term reaction to an outbreak corresponds in this framework to the reaction of governments and individuals to daily cases and fatalities. The reaction to the cumulative number of cases or deaths, and not to daily numbers, is captured in contrast by long-term reaction. We present the exact phase space solution of the controlled SIR model and use it to quantify containment policies for a large number of countries in terms of short and long-term control parameters. We find increased contributions of long-term control for countries and regions in which the outbreak was suppressed substantially together with a strong correlation between the strength of societal and governmental policies and the time needed to contain COVID-19 outbreaks. Furthermore, for numerous countries and regions we identified a predictive relation between the number of fatalities within a fixed period before and after the peak of daily fatality counts, which allows to gauge the cumulative medical load of COVID-19 outbreaks that should be expected after the peak. These results suggest that the proposed model is applicable not only for understanding the outbreak dynamics, but also for predicting future cases and fatalities once the effectiveness of outbreak suppression policies is established with sufficient certainty. Finally, we provide a web app (https://itp.uni-frankfurt.de/covid-19/) with tools for visualising the phase space representation of real-world COVID-19 data and for exporting the preprocessed data for further analysis.

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