scholarly journals Modeling Extinction Risk of Endemic Birds of Mainland China

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Youhua Chen
Keyword(s):  
Extinction Risk ◽  
Mainland China ◽  
Evolutionary Model ◽  
Species Divergence ◽  
Evolutionary Time ◽  
Endemic Birds ◽  
Constant Rate ◽  
Over Time ◽  
Time Plot

The extinction risk of endemic birds of mainland China was modeled over evolutionary time. Results showed that extinction risk of endemic birds in mainland China always tended to be similar within subclades over the evolutionary time of species divergence, and the overall evolution of extinction risk of species presented a conservatism pattern, as evidenced by the disparity-through-time plot. A constant-rate evolutionary model was the best one to quantify the evolution of extinction risk of endemic birds of mainland China. Thus, there was no rate shifting pattern for the evolution of extinction risk of Chinese endemic birds over time. In a summary, extinction risk of endemic birds of mainland China is systematically quantified under the evolutionary framework in the present work.

Foreign Trade, Aid and Economic Growth in Less-Developed Countries by Gunnar Floystad. Oslo: Scandinavian University Books, Universitetsforlaget, 1968.

1968 ◽  
Vol 8 (2) ◽  
pp. 307-308
Author(s):  
Mohammad Anisur Rahman
Keyword(s):  
Economic Growth ◽  
Foreign Trade ◽  
Foreign Aid ◽  
Mainland China ◽  
Developed Countries ◽  
Capital Inflows ◽  
Less Developed Countries ◽  
Constant Rate ◽  
Simple Exponential Function ◽  
Over Time

Gunnar Floystad's Foreign Trade, Aid and Economic Growth is concerned with the interrelations between foreign trade, foreign aid and economic growth of a group of less developed countries (LDC) comprising all of Latin America, Africa, the Middle East and Asia, excluding USSR, Japan and Mainland China. The book is divided into two parts: Part One uses a model of trade, aid and growth to deduce a relationship between GNP, exports and net capital inflows of the LDC. Assuming exports to be given exogenously and net capital inflows to grow at a constant rate over time, growth of GNP is projected corresponding to alternative postulates about growth of exports and growth of net capital inflows via the simple exponential function, E(t) = M0 [X(t) + B(t)]B, where E, X and B stand for GNP, exports and net capital inflows respectively, and M is a constant. Part Two analyses in some details the export prospects for a list of traditional products currently exported from LDC to developed countries.

scholarly journals Kinetics of Anti-SARS-CoV-2 Antibody Responses 3 Months Post Complete Vaccination with BNT162b2; A Prospective Study in 283 Health Workers

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1942
Author(s):  
Evangelos Terpos ◽  
Ioannis P. Trougakos ◽  
Vangelis Karalis ◽  
Ioannis Ntanasis-Stathopoulos ◽  
Sentiljana Gumeni ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Health Workers ◽  
Antibody Responses ◽  
Healthy Individuals ◽  
Younger Age ◽  
Constant Rate ◽  
Rate Of Decline ◽  
A Prospective Study ◽  
Kinetics Of ◽  
Over Time

The aim of this study was to investigate the kinetics of neutralizing antibodies (NAbs) and anti-SARS-CoV-2 anti-S-RBD IgGs up to three months after the second vaccination dose with the BNT162b2 mRNA vaccine. NAbs and anti-S-RBD levels were measured on days 1 (before the first vaccine shot), 8, 22 (before the second shot), 36, 50, and three months after the second vaccination (D111) (NCT04743388). 283 health workers were included in this study. NAbs showed a rapid increase from D8 to D36 at a constant rate of about 3% per day and reached a median (SD) of 97.2% (4.7) at D36. From D36 to D50, a slight decrease in NAbs values was detected and it became more prominent between D50 and D111 when the rate of decline was determined at −0.11 per day. The median (SD) NAbs value at D111 was 92.7% (11.8). A similar pattern was also observed for anti-S-RBD antibodies. Anti-S-RBDs showed a steeper increase during D22–D36 and a lower decline rate during D36–D111. Prior COVID-19 infection and younger age were associated with superior antibody responses over time. In conclusion, we found a persistent but declining anti-SARS-CoV-2 humoral immunity at 3 months following full vaccination with BNT162b2 in healthy individuals.

scholarly journals How predictable is extinction? Forecasting species survival at million-year timescales

2019 ◽  
Vol 374 (1788) ◽  
pp. 20190392 ◽  
Author(s):  
Peter Smits ◽  
Seth Finnegan
Keyword(s):  
Fossil Record ◽  
Human Impacts ◽  
Rank Order ◽  
Extinction Risk ◽  
Geographical Range ◽  
The Past ◽  
The Future ◽  
Out Of Sample ◽  
Extinction Events ◽  
Over Time

A tenet of conservation palaeobiology is that knowledge of past extinction patterns can help us to better predict future extinctions. Although the future is unobservable, we can test the strength of this proposition by asking how well models conditioned on past observations would have predicted subsequent extinction events at different points in the geological past. To answer this question, we analyse the well-sampled fossil record of Cenozoic planktonic microfossil taxa (Foramanifera, Radiolaria, diatoms and calcareous nanoplankton). We examine how extinction probability varies over time as a function of species age, time of observation, current geographical range, change in geographical range, climate state and change in climate state. Our models have a 70–80% probability of correctly forecasting the rank order of extinction risk for a random out-of-sample species pair, implying that determinants of extinction risk have varied only modestly through time. We find that models which include either historical covariates or account for variation in covariate effects over time yield equivalent forecasts, but a model including both is overfit and yields biased forecasts. An important caveat is that human impacts may substantially disrupt range-risk dynamics so that the future will be less predictable than it has been in the past. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

scholarly journals Concurrent and Longitudinal Predictors of Adolescent Delinquency in Mainland Chinese Adolescents: The Role of Materialism and Egocentrism

2020 ◽  
Vol 17 (20) ◽  
pp. 7662
Author(s):  
Daniel T. L. Shek ◽  
Xiang Li ◽  
Xiaoqin Zhu ◽  
Esther Y. W. Shek
Keyword(s):  
Longitudinal Design ◽  
Process Analysis ◽  
Mainland China ◽  
Delinquent Behavior ◽  
Well Being ◽  
Adolescent Delinquency ◽  
Cross Sectional ◽  
Mainland Chinese ◽  
Being There ◽  
Over Time

Background: Although studies have examined the influence of materialism on adolescent well-being, there are several methodological limitations: studies examining the influence of materialism on adolescent delinquency are almost non-existent; researchers commonly used cross-sectional designs; the sample size in some studies was not large; validated measures on materialism in non-Western contexts are rare; there are very few Chinese studies. Besides, no study has examined the hypothesis that egocentrism is the mediator in the influence of materialism on adolescent delinquency. Methods: Using a short-term longitudinal design, two waves of data were collected from 2648 early adolescents in mainland China. At each wave, students completed validated measures of materialism, egocentrism and delinquent behavior. Results: Materialism and egocentrism positively predicted adolescent delinquency at Wave 1 and Wave 2 and over time. While materialism at Wave 1 positively predicted increase in delinquency over time, egocentrism did not. However, PROCESS analysis showed that egocentrism mediated the longitudinal influence of materialism on adolescent delinquent behavior. Conclusions: Materialism and egocentrism are predictors of adolescent delinquency, with egocentrism serving as a mediator in the influence of materialism on adolescent delinquency.

Drivers and trends in the extinction risk of New Zealand's endemic birds

2020 ◽  
Vol 249 ◽  
pp. 108730
Author(s):  
Juan C. Garcia-R ◽  
Moreno Di Marco
Keyword(s):  
Extinction Risk ◽  
Endemic Birds

Uncertain Technology Evolution and Decision Making in Design

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Jonathan L. Arendt ◽  
Daniel A. McAdams ◽  
Richard J. Malak
Keyword(s):  
Research And Development ◽  
Pareto Frontier ◽  
Evolutionary Process ◽  
Evolutionary Model ◽  
Development Effort ◽  
Technology Evolution ◽  
Curve Model ◽  
S Curve ◽  
Over Time

The potential for engineering technology to evolve over time can be a critical consideration in design decisions that involve long-term commitments. Investments in manufacturing equipment, contractual relationships, and other factors can make it difficult for engineering firms to backtrack once they have chosen one technology over others. Although engineering technologies tend to improve in performance over time, competing technologies can evolve at different rates and details about how a technology might evolve are generally uncertain. In this article we present a general framework for modeling and making decisions about evolving technologies under uncertainty. In this research, the evolution of technology performance is modeled as an S-curve; the performance evolves slowly at first, quickly during heavy research and development effort, and slowly again as the performance approaches its limits. We extend the existing single-attribute S-curve model to the case of technologies with multiple performance attributes. By combining an S-curve evolutionary model for each attribute with a Pareto frontier representation of the optimal implementations of a technology at a particular point in time, we can project how the Pareto frontier will move over time as a technology evolves. Designer uncertainty about the precise shape of the S-curve model is considered through a Monte Carlo simulation of the evolutionary process. To demonstrate how designers can apply the framework, we consider the scenario of a green power generation company deciding between competing wind turbine technologies. Wind turbines, like many other technologies, are currently evolving as research and development efforts improve performance. The engineering example demonstrates how the multi-attribute technology evolution modeling technique provides designers with greater insight into critical uncertainties present in long-term decision problems.

Gradual or pulsed evolution: when should punctuational explanations be preferred?

Paleobiology ◽  
2008 ◽  
Vol 34 (3) ◽  
pp. 360-377 ◽  
Author(s):  
Gene Hunt
Keyword(s):  
Random Walk ◽  
Evolutionary Dynamics ◽  
Evolutionary Model ◽  
Information Criterion ◽  
Evolutionary Change ◽  
Statistical Framework ◽  
Size Evolution ◽  
Uniform Model ◽  
Punctuated Evolution ◽  
Over Time

The problem of gradual versus punctuated change within phyletic lineages can be understood in terms of the homogeneity of evolutionary dynamics. Hypotheses of punctuated change imply that the rules governing evolutionary change shift over time such that the normal dynamics of stasis are temporarily suspended, permitting a period of net evolutionary change. Such explanations are members of a larger class of models in which evolutionary dynamics are in some way heterogeneous over time. In this paper, I develop a likelihood-based statistical framework to evaluate the support for this kind of evolutionary model. This approach divides evolutionary sequences into nonoverlapping segments, each of which is fit to a separate evolutionary model. Models with heterogeneous dynamics are generally more complex—they require more parameters to specify—than uniform evolutionary models such as random walks and stasis. The Akaike Information Criterion can be used to judge whether the greater complexity of punctuational models is offset by a sufficient gain in log-likelihood for these models to be preferred.I use this approach to analyze three case studies for which punctuational explanations have been proposed. In the first, a model of punctuated evolution best accounted for changes in pygidial morphology within a lineage of the trilobiteFlexicalymene, but the uniform model of an unbiased random walk remains a plausible alternative. Body size evolution in the radiolarianPseudocubus vemawas neither purely gradual nor completely pulsed. Instead, the best-supported explanation posited a single, pulsed increase, followed later by a shift to an unbiased random walk. Finally, for the much-analyzed claim of “punctuated gradualism“ in the foraminiferaGloborotalia, the best-supported model implied two periods of stasis separated by a period of elevated but not inherently directional evolution. Although the conclusions supported by these analyses generally refined rather than overturned previous views, the present approach differs from those prior in that all competing interpretations were formalized into explicit statistical models, allowing their relative support to be unambiguously compared.

scholarly journals Entry, Exit and Innovation over the Industry Life Cycle in Converging Sectors: An Analysis of the Smartphone Industry

2020 ◽  
Vol 15 (12) ◽  
pp. 151
Author(s):  
Paolo Calvosa
Keyword(s):  
Life Cycle ◽  
Product Innovation ◽  
Evolutionary Model ◽  
Personal Digital Assistants ◽  
Entry And Exit ◽  
Industry Life Cycle ◽  
Digital Convergence ◽  
Convergence Process ◽  
Empirical Regularities ◽  
Over Time

This paper examines the digital convergence process that led to the development of the smartphone sector and the dynamics of entry, exit and innovation over the industry life cycle. We have verified, by a historical-longitudinal study, if several empirical regularities that characterize the evolution of firms and industries over time have distinguished also an industry born from a sectoral convergence process. From the analysis it emerged that the evolution of market sales and of product innovation in the smartphone industry, as well as firms entry and exit dynamics, are consistent with the evolutionary model identified by technology management and industry life cycle studies. It has also been found that the convergence process has favored the entry and the survival of new entrants, compared to the incumbent firms, coming from the native converging sectors – that of Personal digital assistants and of Mobile (feature) phones – from which the smartphone industry originated.

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