128 research outputs found
Die profiel van die adolessente seun as mentee aan die Weskus
Adolescent boys long to be mentored by an adult male. This influence of the mentor in the life of the adolescent brings forth great changes and consequently the adolescent experiences a higher quality of life. This mentee is not necessarily mentored by his biological father. The adolescent boy as mentee has certain needs within the mentoring relationship, which the mentor has to understand and interpret correctly. If the mentor understands the mentee better within his generation, the relationship may be strengthened. This article focuses on the profile of the adolescent boy as mentee on the West Coast and indeed from the viewpoint of the adolescent
Supercooled confined water and the Mode Coupling crossover temperature
We present a Molecular Dynamics study of the single particle dynamics of
supercooled water confined in a silica pore. Two dynamical regimes are found:
close to the hydrophilic substrate molecules are below the Mode Coupling
crossover temperature, , already at ambient temperature. The water closer
to the center of the pore (free water) approaches upon supercooling as
predicted by Mode Coupling Theories. For free water the crossover temperature
and crossover exponent are extracted from power-law fits to both the
diffusion coefficient and the relaxation time of the late region.Comment: To be published, Phys. Rev. Lett., 4 pages, 3 figures, revTeX, minor
changes in the figures, references added, changes in the tex
Temperature Evolution of Sodium Nitrite Structure in a Restricted Geometry
The NaNO nanocomposite ferroelectric material in porous glass was
studied by neutron diffraction. For the first time the details of the crystal
structure including positions and anisotropic thermal parameters were
determined for the solid material, embedded in a porous matrix, in ferro- and
paraelectric phases. It is demonstrated that in the ferroelectric phase the
structure is consistent with bulk data but above transition temperature the
giant growth of amplitudes of thermal vibrations is observed, resulting in the
formation of a "premelted state". Such a conclusion is in a good agreement with
the results of dielectric measurements published earlier.Comment: 4 pages, 4 figure
Overseeing the overseers: assessing compliance with municipal intervention rules in South Africa
Section 139 of the Constitution of South Africa empowers provinces to intervene into municipalities, an instrument to correct serious failures in local government. This article discusses the policy and legal framework for interventions and assesses whether the constitutional provisions that circumscribe it, are being adhered to. The starting point is that decentralisation, of which this instrument is part, is rules-based and that adherence to the rule of law is critical for its success. By its very nature, intervention represents an intrusion into the institutional integrity of the affected municipality and adherence to the constitutional safeguards surrounding the intervention is therefore critical. The article sets out the constitutional framework for interventions into municipalities which includes oversight roles for the Minister responsible for local government, the National Council of Provinces and the provincial legislature. It combines this with an assessment of 39 interventions that took place between 2008 and 2014. It presents a provincial breakdown and a breakdown of the legal basis of these 39 interventions. It concludes that provinces don’t use the interventions envisaged in Section 139(4) and (5) but instead almost always intervene in terms of Section 139(1) of the Constitution. The interventions are assessed for compliance with constitutional prescripts, such as the need to establish a failure to fulfil an executive obligation, the timely submission of the intervention to the Minister and the NCOP and their timely approval. The article concludes that a significant number of interventions did not comply with the pro- visions pertaining to the timely submission and approval by the Minister and the NCOP. Furthermore, there is a need to accelerate the adoption of the legislation envisaged by Section 139(8) of the Constitution to further regulate interventions
Neutron reflection study of the adsorption of the phosphate surfactant NaDEHP onto alumina from water.
The adsorption of a phosphorus analogue of the surfactant AOT, sodium bis(2-ethylhexyl) phosphate (NaDEHP), at the water/alumina interface is described. The material is found to adsorb as an essentially water-free bilayer from neutron reflection measurements. This is similar to the behavior of AOT under comparable conditions, although AOT forms a thicker, more hydrated layer. The NaDEHP shows rather little variation with added salt, but a small thickening of the layer on increasing the pH, in contrast to the behavior of AOT.We thank BP plc and EPSRC for financial support for this work as well as the ISIS and ILL staff and scientists for the allocation of beam time and technical assistance with NR measurements. We also appreciate Chris Sporikou at Department of Chemistry, University of Cambridge, for help with the surfactant synthesis.This is the final version of the article. It first appeared at http://dx.doi.org/10.1021/la504837
Rate of Molecular Transfer of Allyl Alcohol across an AOT Surfactant Layer Using Muon Spin Spectroscopy
Experimental evidence of the ferroelectric phase transition near the point in liquid water
We studied dielectric properties of nano-sized liquid water samples confined
in polymerized silicates MCM-41 characterized by the porous sizes \sim 3-10nm.
We report the direct measurements of the dielectric constant by the dielectric
spectroscopy method at frequencies 25Hz-1MHz and demonstrate clear signatures
of the second-order phase transition of ferroelectric nature at temperatures
next to the \lambda- point in the bulk supercooled water. The presented results
support the previously developed polar liquid phenomenology and hence establish
its applicability to model actual phenomena in liquid water.Comment: 4 pages, single figur
Adult population ecology and egg laying strategy in the ‘cruciata’ ecotype of the endangered butterfly Maculinea alcon (Lepidoptera: Lycaenidae)
Effects of puff adder venom on coagulation, fibrinolysis and platelet aggregation in the baboon
The original version is available at http://www.samj.org.za/BibliographyThe in vitro and in vivo hematological effects of puff adder (Bitis arietans) venom in the baboon (Papio ursinus) with regard to its effect on coagulation, fibrinolysis and platelet aggregation were studied. There is a delay in the intrinsic coagulation mechanism with fibrinolysis and in vitro fibrinogenolysis. Normal human platelets demonstrated an extreme susceptibility to puff adder venom in vitro. The aggregation of platelets with small dosages of venom was irreversible. The effect is related to the dosage, and appears to be the result of multiple enzyme activities, some of which are heat labile. In minimal amounts there is evidence of consumption of blood coagulation factors with sustained thrombocytopenia, but no fibrinolysis, where heparin therapy might have a beneficial effect. With larger dosages of venom the thrombocytopenia, hemorrhagic effects and shock are not prevented or corrected by heparin and heparinisation might even be harmful. The effect of heparin should be further investigated, since it might have a place in mildly affected cases of snakebite, where absorption into the blood has been slow or intermittent. It might be indicated when antivenene is not available or when patients are sensitive to serum.Publishers'Versio
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