1,340 research outputs found
Feeding ecology of sprat (Sprattus sprattus L.) and sardine (Sardina pilchardus W.) larvae in the German Bight, North Sea
The abundance of the sardine in the North Sea suddenly increased after 1995. Since 2002, the sardine has been spawning regularly in the German Bight, and all its life stages can be found in the area. The larval feeding ecology of two small pelagic clupeiform species with very similar life histories was investigated, the particular aim being to determine signs of food overlap. The distribution and feeding of sprat and sardine larvae were investigated during late spring 2003 on two transects covering a wide range of environmental conditions in the German Bight. Larvae co-occurred at all the stations investigated. Sprat and sardine larvae shared a wide range of prey types. Gut fullness and feeding success were similar in both species; however, potential food competition is avoided to some extent by different habitat preferences
Natriuretic peptide receptors on rat thymocytes: Inhibition of proliferation by atrial natriuretic peptide.
Because the thymus expresses the natriuretic peptides (NP) as well
as their respective receptors, an involvement of NP in the physiology
of this organ has been suggested. To evaluate functional aspects of NP
in the thymus, we looked for thymic cells bearing NP receptors (Npr).
Furthermore, the regulation of Npr expression by activation of cells
and the influence of NP on the proliferation of thymocytes was studied.
Expression of receptor messenger RNAs CmRNAs) was examined
by PCR and Northern blot. Existence of functional Npr was confirmed
by measurement of cGMP, the second messenger of NP. Proliferation
of thymocytes upon concanavalin A (Con A) stimulation was analyzed by incorporation of [“Hlthymidine. We report here that thymocytes express mRNAs for the three Npr, namely Npra, Nprb, and Nprc and
that activation of Npra and Nprb increases cGMP levels. Stimulation
of thymocytes with Con A (1 pg/ml, 48 h) resulted in an increase of
mRNA coding for Npra, the receptor specific for atria1 natriuretic
peptide (ANP) and brain natriuretic peptide. Nprb and Nprc receptor
expression was not altered under these conditions. In agreement with
these data only ANP, but not the C-type natriuretic peptide, elicited
increased cGMP response in Con A-stimulated cells. ANP inhibited
also the proliferation of Con A stimulated thymocytes, whereas C-type
natriuretic peptide did not show this effect. These results suggest that
ANP affects the complex mechanisms of thymocyte proliferation and
differentiation
To be Made Disabled, A Discourse Analysis of Intellectual Disability in New Zealand, 1900 - 1960
The New Zealand historiography on intellectual disability has been expanded in the twenty years by histories of the residential institution and the foundation of advocacy groups. However, there is still a limited field of history regarding how the intellectually disabled were discussed in twentieth century New Zealand. This thesis will discuss how the identity of the intellectually disabled was constructed as a social category, through different discourses, in twentieth century New Zealand. It shall be argued that from 1900 to at least 1960 those who created medical, government and public discourse also maintained the power to create the identity of the intellectually disabled. This argument will take the form of a discourse analysis and will draw on both primary and secondary sources. The primary sources will include government documents, medical literature and newspaper content. The secondary sources will cover material which provides context, and / or which has discussed the construction of intellectual disability. It will be argued that discourses centred on an idea of a 'problem' within the intellectually disabled individual. Also, the medical discourse and 'medicalized' understandings of intellectual disability will be seen to influence public and government discourse. Further, a tension will be shown in these discourses between the desire to assist the intellectually disabled and their families, as well as to protect the New Zealand community from these people
Dielectric tensor of monoclinic GaO single crystals in the spectral range eV
The dielectric tensor of -GaO was determined by generalized
spectroscopic ellipsometry in a wide spectral range from to
as well as by calculation including quasiparticle bands and
excitonic effects. The dielectric tensors obtained by both methods are in
excellent agreement with each other and the observed transitions in the
dielectric function are assigned to the corresponding valence bands. It is
shown that the off-diagonal element of the dielectric tensor reaches values up
to and cannot be neglected. Even in the
transparent spectral range where it is quite small () it causes a rotation of the dielectric axes around the symmetry axis of up
to
Nonlocal gross-pitaevskii equation with cylindrical symmetry: semiclassical asymptotics and error
Nonlocal Gross-Pitaevskii equation (GPE) with cylindrical symmetry has been considered. The semiclassical solution, concentrated on a curve in the phase space, has been constructed. The error has been calculated for obtained the semiclassical solution. Both stability of semiclassical solution and limitedness of the error suggest that the exact solution is stable too
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