13 research outputs found
The Probability for Formation of Collapsing Textures and Texture Knots
Global textures are interesting because they are promising candidates for
seeds in the structure formation of the universe. The important configurations
are those who will be able to collapse. The type of configurations that I will
consider are half knots and true knots. I define a half knot as one that covers
more than a half-, and a true knot as a configuration that covers the
whole of . Configurations that are half knots will be able to collapse, a
new argument for this collapse criterion is given in this paper. I also give
some critical remarks on the method of using the total winding number as a
criterion for identifying a knot. I propose another more direct method and make
use of it when I estimate the probability for formation of both true and half
knots by numerical simulations.Taking into account the chance of annihilation
the probability for collapse is found to be in the interval . In the skyrmion picture of hadrons the investigations of
formation of true knots are important, and some implications of my result on
the predictions of a "topological" theory of baryon production in jets are
discussed.Comment: 12 pages, 9 figures (not included), LATEX, (rev. may 1992
Estrogen Sensitivity of Target Genes and Expression of Nuclear Receptor Co-Regulators in Rat Prostate after Pre- and Postnatal Exposure to the Ultraviolet Filter 4-Methylbenzylidene Camphor
On Self-Similar Global Textures in an expanding Universe
We discuss self-similar solutions to textures in Minkowski space and
in flat Friedmann-Robertson-Walker backgrounds. We show that in the Minkowski
case there exist no solutions with winding number greater than unity. However,
we find besides the known solution with unit winding number also previously
unknown solutions corresponding to winding number less than one. The validity
of the non-linear sigma model approximation is discussed. We point out that no
spherically symmetric exactly self-similar solutions exist for radiation or
matter dominated FRW cosmologies, but we find a way to relax the assumptions of
self-similarity that give us approximative solutions valid on intermediate
scales.Comment: 12 pages (LaTeX) + 1 postscript figure. To appear in Phys. Lett
Endocrine Active UV Filters: Developmental Toxicity and Exposure Through Breast Milk
Several UV filters exhibit endocrine activity. Evidence for transdermal passage and presence in the food chain (fish) suggests potential exposure of humans during development. Developmental toxicity was studied in rats for the estrogenic UV filters 4-methylbenzylidene camphor (4-MBC,
0.7, 7, 24, 47 mg/kg/day) and 3-benzylidene camphor (3-BC, 0.07, 0.24, 0.7, 2.4, 7 mg/kg/day) administered in chow to the parent generation before mating, during pregnancy and lactation, and to the offspring until adulthood. Neonates exhibited enhanced prostate growth after 4-MBC and altered
uterine gene expression after both filters. 4-MBC and 3-BC delayed male puberty and affected reproductive organ weights of adult offspring. Interactions with the thyroid were noted. Expression and estrogen sensitivity of target genes and nuclear receptor coregulators were altered at mRNA and
protein levels in adult uterus, prostate and brain. Female sexual behavior was affected by 4-MBC and 3-BC, estrous cycles by 3-BC. Classical endpoints exhibited LOAELs/NOAELs of 7/0.7 mg/kg/day for 4-MBC and 0.24/0.07 mg/kg/day for 3-BC. Molecular endpoints were affected by the lowest doses.
In order to obtain information on human exposure, we conducted a monitoring study on human milk with three series of mother–child pairs (2004, 2005, 2006), with focus on cosmetic UV filters in relation to other endocrine disrupters. Methods for UV filter analysis followed the principles
of European standardized methods for pesticide residue analysis (EN 15289). In cohorts 2004 and 2005, 78.8% of women reported use of product(s) containing cosmetic UV filters in a questionnaire, and 76.5% of milk samples contained these filters. Use of UV filters and concentration in human
milk were significantly correlated. The results agree with the idea of transdermal passage of UV filters. They also indicate that it may be possible to reduce human exposure during critical periods such as pregnancy and lactation by transiently abstaining from use
Categorizing Different Approaches to the Cosmological Constant Problem
We have found that proposals addressing the old cosmological constant problem
come in various categories. The aim of this paper is to identify as many
different, credible mechanisms as possible and to provide them with a code for
future reference. We find that they all can be classified into five different
schemes of which we indicate the advantages and drawbacks.
Besides, we add a new approach based on a symmetry principle mapping real to
imaginary spacetime.Comment: updated version, accepted for publicatio
Effects of autologous bone marrow stem cell transplantation on beta-adrenoceptor density and electrical activation pattern in a rabbit model of non-ischemic heart failure
BACKGROUND: Since only little is known on stem cell therapy in non-ischemic heart failure we wanted to know whether a long-term improvement of cardiac function in non-ischemic heart failure can be achieved by stem cell transplantation. METHODS: White male New Zealand rabbits were treated with doxorubicine (3 mg/kg/week; 6 weeks) to induce dilative non-ischemic cardiomyopathy. Thereafter, we obtained autologous bone marrow stem cells (BMSC) and injected 1.5–2.0 Mio cells in 1 ml medium by infiltrating the myocardium via a left anterolateral thoracotomy in comparison to sham-operated rabbits. 4 weeks later intracardiac contractility was determined in-vivo using a Millar catheter. Thereafter, the heart was excised and processed for radioligand binding assays to detect β(1)- and β(2)-adrenoceptor density. In addition, catecholamine plasma levels were determined via HPLC. In a subgroup we investigated cardiac electrophysiology by use of 256 channel mapping. RESULTS: In doxorubicine-treated animals β-adrenoceptor density was significantly down-regulated in left ventricle and septum, but not in right ventricle, thereby indicating a typical left ventricular heart failure. Sham-operated rabbits exhibited the same down-regulation. In contrast, BMSC transplantation led to significantly less β-adrenoceptor down-regulation in septum and left ventricle. Cardiac contractility was significantly decreased in heart failure and sham-operated rabbits, but was significantly higher in BMSC-transplanted hearts. Norepinephrine and epinephrine plasma levels were enhanced in heart failure and sham-operated animals, while these were not different from normal in BMSC-transplanted animals. Electrophysiological mapping revealed unaltered electrophysiology and did not show signs of arrhythmogeneity. CONCLUSION: BMSC transplantation improves sympathoadrenal dysregualtion in non-ischemic heart failure
ERM Report 2020: Die Rolle der Risk Manager in der COVID-19 Krise
Kein Abstract vorhanden+ ID der Publikation: hslu_81206 + Art des Beitrages: Studie oder Gutachten + Sprache: Deutsch + Letzte Aktualisierung: 2020-12-17 14:43:5