scholarly journals SIZE VARIATION, GROWTH STRATEGIES, AND THE EVOLUTION OF MODULARITY IN THE MAMMALIAN SKULL

Evolution ◽  
2013 ◽  
Vol 67 (11) ◽  
pp. 3305-3322 ◽  
Author(s):  
Arthur Porto ◽  
Leila Teruko Shirai ◽  
Felipe Bandoni de Oliveira ◽  
Gabriel Marroig
Keyword(s):  
Size Variation ◽  
Growth Strategies ◽  
Mammalian Skull

Genetik der Körperhöhe

2019 ◽  
Vol 13 (03) ◽  
pp. 139-144
Author(s):  
Michael Hermanussen ◽  
Christiane Scheffler ◽  
Barry Bogin
Keyword(s):  
Peer Group ◽  
Competitive Growth ◽  
Growth Strategies ◽  
Missing Heritability

Zusammenfassung Hintergrund Noch immer gründen heutige Analysen genetischer Zwillings- und Familienstudien auf mathematischen Ansätzen des frühen 20. Jahrhunderts, namentlich von Galton, Pearson und Fisher, und führen zu konventionellen Schätzwerten für die Heritabilität der Körperhöhe zwischen h² = 0,87 und h² = 0,93 bei Männern und zwischen h² = 0,68 und h² = 0,84 bei Frauen. Diese Werte sind wesentlich höher als moderne Schätzungen auf der Basis genomweiter Assoziationsstudien (GWAS), mit denen sich zwischen 12,3 % und 49 % der Körperhöhenvarianz im Erwachsenenalter erklären lassen. Diese so genannte „missing heritability“ gibt Anlass zu Missverständnissen. Diskussion Wir nehmen eine biokulturelle Perspektive ein, um Entwicklungsmerkmale zu verstehen, die nur auf den ersten Blick erblich erscheinen. Innerhalb sozialer Gruppen dient Körpergröße als Signal. Kompetitive Wachstumsstrategien (competitive growth strategies) und strategische Wachstumsanpassungen (strategic growth adjustments) insbesondere im Hinblick auf die Gefahr, aus einer führenden sozialen Rolle verdrängt zu werden (threat of being displaced) sind bei sozialen Säugern beschrieben und spielen sehr wahrscheinlich auch in menschlichen Sozialstrukturen eine wesentliche Rolle. Die Körperhöhe eines Menschen hängt von der Körperhöhe anderer Mitglieder seiner Peer Group ab. Im vergangenen Jahrhundert wurden Körperhöhentrends von bis zu 20 cm in manchen Populationen beobachtet (säkulare Trends). Dies ist Ausdruck von phänotypischer Plastizität und war Galton, Pearson und Fisher unbekannt. Schlussfolgerung Die beschriebene „missing heritability“ für Körperhöhe spiegelt die Diskrepanz zwischen moderner Wissenschaft und überholten Vermengungen von deterministischen und politischen Ideen des frühen 20. Jahrhunderts wider.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Amiya Kumar Bagchi. The Political Economy of Underdevelopment. London: Cambridge University Press. 1982. Reprint 1983. pp.viii+276. List of books for further reading; Index. Price: £ 8.50 (paperback edition).

1985 ◽  
Vol 24 (1) ◽  
pp. 77-82
Author(s):  
Zia Ul Haq
Keyword(s):  
Economic Growth ◽  
Economic Development ◽  
Third World ◽  
Social Process ◽  
Growth Strategies ◽  
Cambridge University ◽  
Working Classes ◽  
The Third ◽  
The Rich ◽  
The Third World

Amiya Kumar Bagchi, an eminent economist of the modern Cambridge tradition, has produced a timely treatise, in a condensed form, on the development problems of the Third World countries. The author's general thesis is that economic development in the developing societies necessarily requires a radical transformation in the economic, social and political structures. As economic development is actually a social process, economic growth should not be narrowly defined as the growth of the stock of rich capitalists. Neither can their savings be equated to capital formation whose impact on income will presumably 'trickle down' to the working classes. Economic growth strategies must not aim at creating rich elites, because, according to the author, "maximizing the surplus in the hands of the rich in the Third World is not, however, necessarily a way of maximizing the rate of growth".

Corporate Growth Strategies and Performance of Selected Savings and Credit Cooperative Societies in Nairobi City County, Kenya

2020 ◽  
Vol 2 (2) ◽  
pp. 19-30
Author(s):  
Hamida Mwilu ◽  
Reuben Njuguna
Keyword(s):  
Data Collection ◽  
Business Environment ◽  
Primary Data ◽  
Growth Strategies ◽  
Inferential Statistics ◽  
Market Expansion ◽  
Acquisition Strategies ◽  
Corporate Growth ◽  
Diversification Strategies ◽  
And Performance

The dynamic nature of business operating environment has called on business leaders to be strategic in their leadership roles if they are to sustain their competitiveness into the unforeseen future. Growth is important in Sacco’s because it is future oriented establishing ways in which the organizational operations can be aligned to future changes in the business environment to ensure that competitiveness is sustained. The SACCOs in Kenya have experienced problems in the past; some even shutting down therefore there is need for customer growth to be enhanced so as to increase their incomes so as to sustain the business. These SACCOs have to look for leaders and managers who can develop future targets, direct and lead other staffs towards meeting the firm’s objective and gaining a competitive edge. The aim of this study was an assessment of corporate growth strategies and performance in savings and cooperative societies in Kenya, Nairobi County. The study sought to determine the influence of market expansion, diversification strategies and acquisition strategies. The study target population was 41 licensed SACCOs in Nairobi County. The study used primary data to collect information, and the data collection instrument was a questionnaire which was given to the 41 operations managers in the 41 selected SACCOs. The data collection procedure was done by the researcher and drop-and-pick strategy will be applied. The data was coded and keyed in Statistical Package for Social Science (SPSS Version 23.0), and was analyzed using both descriptive and inferential statistics. For descriptive statistics was through mean scores, standard deviations, frequencies and percentages, while the inferential statistics was through regression analysis to establish the relationship between strategic leadership and customer growth. The findings were presented in tables and charts for easy understanding, interpreting, and describing the data. The study established that market expansion, diversification strategies and acquisition strategies as corporate growth strategies had a positive and significant effect on the performance of SACCOs in Nairobi City County. The study concluded that the SACCOs significantly employed market expansion strategies through improved branch network, customer base enhancement, new distribution channels and technological innovation. The study concluded that the SACCOs embraced a hybrid of the main diversification strategies, diverse products and services significantly. It was concluded that to a little extent the selected SACCOs in Nairobi City County have employed acquisition as a corporate growth strategy. The study recommends that the SACCOs should embrace integrate technology in the implementation of corporate growth strategies to enhance efficiency and effectiveness.  Further studies should be undertaken to establish the effect of corporate growth strategies on the performance of other SACCOs in other regions to establish the disparities or similarities among the financial sector players. 

Documenting Intraspecfic Genome Size Variation in Soybean

Crop Science ◽  
2004 ◽  
Vol 44 (1) ◽  
pp. 261 ◽  
Author(s):  
A. Lane Rayburn ◽  
D. P. Biradar ◽  
R. L. Nelson ◽  
R. McCloskey ◽  
K. M. Yeater
Keyword(s):  
Genome Size ◽  
Size Variation ◽  
Genome Size Variation
Sign in / Sign up

Export Citation Format

Share Document