Experimental Tests of Neutron Shielding for the ATLAS Forward Region

Experimental tests devoted to the optimization of the neutron shielding for the ATLAS forward region were performed at the CERN-PS with a 4 GeV/c proton beam. Spectra of fast neutrons, slow neutrons and gamma rays escaping a block of iron (40$\times$40$\times$80 cm$^3$) shielded with different types of neutron and gamma shields (pure polyethylene - PE, borated polyethylene - BPE, lithium filled polyethylene - LiPE, lead, iron) were measured by means of plastic scintillators, a Bonner spectrometer, a HPGe detector and a slow neutron detector. Effectiveness of different types of shielding agaisnt neutrons and $\gamma$-rays were compared. The idea of a segmented outer layer shielding (iron, BPE, iron, LiPE) for the ATLAS Forward Region was also tested

Sex Differences in Somatic and Functional Characteristics of Preschool Children

Two samples of preschool children were studied serially from the point of view of somatic and functional development: 246 boys and girls from 3 to 6 years. A representative cross-sectional sample of 5449 children of both sexes from Bohemia and Moravia was studied at the age of 6.4 years. Marked sexual differentiation was apparent in both samples—boys were taller, heavier, with longer measurements on the trunk and extremities, greater transverse and antero-posterior chest dimensions, greater skeletal robustieity (i.e. greater hand and wrist breadth, broader bicondylar humerus and femur and ankle breadths), greater circumferences (head, neck, chest) which were obviously due to greater lean laxly mass. Also hand grip strength, performance in 20m dash, broad jump from the spot and cricket ball throw by both hands were greater in the boys. Girls showed greater thigh and arm circumferences, and more subcutaneous fat measured by Best and Harpenden calipers on both body sites. There were no sex differences in the reaction of the cardiovascular system during a modified step test representing the standard work load. With advancing age along with increasing bodily dimensions and muscular strength, subcutaneous fat decreased in boys but did not change in girls. The economy of work of the cardiovascular system during the step test improved significantly as well as the performance in mentioned disciplines in children of both sexes

Long-term effects of stem girdling on needle structure in Scots pine

Stem girdling is the process of completely removing a strip of cork and phloem tissue. Phloem is the living tissue which serves as the main long-distance pathway for transporting carbohydrates produced during photosynthesis to all parts of the plant where needed, from source leaves to sinks. Stem girdling has been used to study several functional aspects of phloem and their direct impacts on tree growth. Although both photosynthesis and transpiration processes take place in needles, no studies exist which investigate the effect of source-sink disturbance on needle structure. In this study, we evaluated changes in needle morphology and anatomy in current-year Scots pine needles 227 and 411 days after girdling (DAG). Although the studied needle parameters recorded 227 DAG were from 2 to 20% higher than the same parameters in control needles, the differences were not significant. On the other hand, needles 411 DAG were thinner, with decreased cross-sectional areas, phloem areas, vascular cylinder areas, needle dry mass, needle density, and needle flatness when compared to control needles. Marked variations in needle growth were observed 411 DAG, with a smaller number of correlations among almost all studied needle parameters in needles 411 DAG when compared to control needles or needles 227 DAG. Structural development determining needle flatness, needle density, and leaf mass per area (LMA) appeared to have driving factors that were independent of the other studied needle parameters, as correlations with other parameters were not significant in any treatment. The changes in overall needle structure observed after long-term stem girdling provide new insights into the processes that occur as a result of source-sink disturbances. This type of data could be helpful, for example, in studies specifically focused on phloem transport, tree carbon relationships, or investigations modeling gas exchange. Our study might also support gene expression studies, which could provide further knowledge about the regulatory mechanisms that determine needle size and structural form