the present study investigates the effect of different exposure densities on third grade iranian junior high school (ijhs) students’ efl development and retention. it also attempts to explore whether there is any differential performance due to type of post-exposure assessment tasks (recognition vs. written production). performances of five groups of learners receiving equal amount of exposure ...

In considering the likelihood of South Africa (SA) attaining the 2015 Millennium Development Goals, many health issues require urgent attention. The adverse effect of insufficient or excessive exposure to solar ultraviolet radiation (UVR) may exacerbate an already stressed public health service. These concerns become important when considering climate variability and patterns of behaviour. Lati...

Introduction: Finding evidence for an irradiation of chondrules by energetic particles in the solar nebula prior to their incorporation into meteoritic matter (pre-compaction exposure) might yield information about the early solar energetic particle environment and also constrain the lifespan of chondrules as freely floating objects in the nebula. In a pioneering study, [1] searched for unusual...

Bulk-heterojunction (BHJ) solar cells based on organic small molecules and polymers are the focus of increasing attention by science and commerce. In organic photovoltaic devices, a conjugated polymer layer is used as the donor, while a fullerene-based derivative is used as the acceptor. Poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is one of the most common interfacial ma...

There is an ongoing debate how to balance between beneficial and adverse effects of UV-exposure. On the one hand, solar UV-radiation represents the most important environmental risk factor for the development of non-melanoma skin cancer. Therefore, sun protection is a key principle to prevent these malignancies, especially in risk groups. On the other hand, artificial or solar UV-radiation is r...