Wheat was domesticated about 10,000 years ago and has since spread worldwide to become one of the major crops. Its adaptability to diverse environments and end uses is surprising given the diversity bottlenecks expected from recent domestication and polyploid speciation events. Wheat compensates for these bottlenecks by capturing part of the genetic diversity of its progenitors and by generating new diversity at a relatively fast pace. Frequent gene deletions and disruptions generated by a fast replacement rate of repetitive sequences are buffered by the polyploid nature of wheat, resulting in subtle dosage effects on which selection can operate.

https://science.sciencemag.org/content/sci/316/5833/1862.full.pdf

Genome Plasticity a Key Factor in the Success of Polyploid Wheat Under Domestication

Most previous research on effects of schooling has concluded that the effect of school or teacher quality on academic achievement is less than that of family background or other characteristics of students that predate entry into school. However, the evidence for that generalization is derived mainly from a few of the world's school systems. This paper explores diverse influences on pupil achievement in Africa, Asia, Latin America, and the Middle East. Children who attend primary school in countries with low per capita incomes have learned substantially less after similar amounts of time in school than have pupils in high income countries. At the same time, the lower the income of the country, the weaker the influence of pupils' social status on achievement. Conversely, in low income countries, the effect of school and teacher quality on academic achievement in primary school is comparatively greater. From these data it is possible to conclude that the predominant influence on student learning is the quality of the schools and teachers to which children are exposed.

/pdf/the-effect-of-primary-school-quality-on-academic-achievement-3j8qoq7m39.pdf

The Effect of Primary-School Quality on Academic Achievement across Twenty-nine High- and Low-Income Countries

Growing interest in global environmental issues has led to the need for global and regional assessment of water resources. A global water assessment model called "WaterGAP 2" is described, which consists of two main components—a Global Water Use model and a Global Hydrology model. These components are used to compute water use and availability on the river basin level. The Global Water Use model consists of (a) domestic and industry sectors which take into account the effect of structural and technological changes on water use, and (b) an agriculture sector which accounts especially for the effect of climate on irrigation water requirements. The Global Hydrology model calculates surface runoff and groundwater recharge based on the computation of daily water balances of the soil and canopy. A water balance is also performed for surface waters, and river flow is routed via a global flow routing scheme. The Global Hydrology model provides a testable method for taking into account the effects of climate and land cover on runoff. The components of the model have been calibrated and tested against data on water use and runoff from river basins throughout the world. Although its performance can and needs to be improved, the WaterGAP 2 model already provides a consistent method to fill in many of the existing gaps in water resources data in many parts of the world. It also provides a coherent approach for generating scenarios of changes in water resources. Hence, it is especially useful as a tool for globally comparing the water situation in river basins.

/pdf/development-and-testing-of-the-watergap-2-global-model-of-cel9ibeg6b.pdf

Development and testing of the WaterGAP 2 global model of water use and availability

Effect of road traffic on amphibian density

The labor force participation rate of married women first declines and then rises as countries develop. Its þ-shape is revealed both across the process of economic development and through the histories of currently advanced countries. The initial decline in the participation rate is due to the movement of production from the household, family farm, and small business to the wider market, and to a strong income effect. But the income effect weakens and the substitution effect strengthens at some point. This paper explores why the change takes place and why the þ-shape is traced out. When women are poorly educated their only wage labor outside the home and family is in manual work, against which a strong social stigma exists. But when women are educated, particularly at the secondary level, they enter white-collar work, against which no social stigma exists. Data for more than one-hundred countries and for United States history are used to explore the hypothesis of the þ-shaped female labor force function.

韓國統計研究所

Papers

統計年鑑 = Statistical yearbook