Chitosan (CS) and alginate (Alg) are complementary in their membrane performance, but the combination of them is normally difcult to use due to their different solubilities. Layer-by-Layer deposition appears to be an effective method for improving the separation efciency of a composite membrane. In this work, the polyelectrolyte multilayer composite membranes (PEMCMs) wer...

ÐA growing body of literature suggests that there is an optimal size for software components. This means that components that are too small or too big will have a higher defect content (i.e., there is a U-shaped curve relating defect content to size). The U-shaped curve has become known as the ªGoldilocks Conjecture.º Recently, a cognitive theory has been proposed to explain this phenomenon and...

The paper reviews research into class size effects from a methodological viewpoint, especially concentrating on the various strengths and weaknesses of randomised controlled trials and observational studies. It sets out the criteria for valid inferences from such studies and illustrates these using a reanalysis of the large data set from the Tennessee STAR study.

Cohesion is an important software attribute, and it is one of significant criteria for assessing object-oriented software quality. Although several metrics for measuring cohesion have been proposed, there is an aspect which has not been supported by those existing metrics, that is “cohesive-part size.” This paper proposes a new metric focusing on “cohesive-part size,” and evaluates it in both o...

The high stakes testing and school accountability components of our K-12 education system create an incentive for principals to behave strategically to maximize school performance. One possible approach is the adjustment of class sizes based on observed teacher effectiveness. Conceptually, this relationship may be positive or negative. On one hand, performance-maximizing principals may place mo...

We estimate the effect of class size on student performance in 18 countries, combining school fixed effects and instrumental variables to identify random class-size variation between two adjacent grades within individual schools. Conventional estimates of class-size effects are shown to be severely biased by the non-random placement of students between and within schools. Smaller classes exhibi...

We analyze teacher experience as a moderating factor for the effect of class size reduction on student achievement in the early grades using data from the Tennessee STAR experiment with random assignment of teachers and students to classes of different size. The analysis is motivated by the high costs of class size reductions and the need to identify the circumstances under which this investmen...

Background and objectives: Acne vulgaris is one of the most common dermatologic conditions. The available anti-acne treatments are not satisfactory and safe. In...

many results were proved on the structure of finite groups with some‎ ‎restrictions on their real elements and on their conjugacy classes‎. ‎we‎ ‎generalize a few of these to some classes of infinite groups‎. ‎we study groups in which real elements are central‎, ‎groups in which real elements are $2$-elements‎, ‎groups in which all non-trivial classes have the same finite size and $fc$-groups w...