1,789 research outputs found
A microscopic model for solidification
We present a novel picture of a non isothermal solidification process
starting from a molecular level, where the microscopic origin of the basic
mechanisms and of the instabilities characterizing the approach to equilibrium
is rendered more apparent than in existing approaches based on coarse grained
free energy functionals \`a la Landau.
The system is composed by a lattice of Potts spins, which change their state
according to the stochastic dynamics proposed some time ago by Creutz. Such a
method is extended to include the presence of latent heat and thermal
conduction.
Not only the model agrees with previous continuum treatments, but it allows
to introduce in a consistent fashion the microscopic stochastic fluctuations.
These play an important role in nucleating the growing solid phase in the melt.
The approach is also very satisfactory from the quantitative point of view
since the relevant growth regimes are fully characterized in terms of scaling
exponents.Comment: 7 pages Latex +3 figures.p
17beta-estradiol suppresses TLR3-induced cytokine and chemokine production in endometrial epithelial cells
BACKGROUND: The human endometrium is an important site for contact between the host and pathogens ascending the reproductive tract, and thus plays an important role in female reproductive tract immunity. Previous work in our laboratory has suggested that Toll-like receptors (TLRs) are involved in endometrial epithelial recognition of pathogens and that ligation of endometrial TLRs results in the production of cytokines and chemokines important for both immune and reproductive functions of the endometrium. We have also demonstrated cyclic regulation of TLR3 mRNA and protein expression in human endometrium, suggesting that steroid hormones might play a role in the expression and function of TLR3. In this study, the effects of 17beta-estradiol (E2) and progesterone (P) on TLR3 expression and function in endometrial cell lines were investigated. METHODS: Endometrial epithelial cell lines were cultured and examined for the presence of TLR3 and hormone receptors by endpoint RT-PCR. For hormonal studies, cells were pre-treated with ethanol vehicle, 10^(-8) M E2, and/or 10^(-7) M P. For antagonist assays, cells were treated with the ER antagonist, ICI 182, 780, or the PR antagonist, RU486, for two hours prior to treatment with hormones. Following hormone or hormone/antagonist pre-treatment, cells were stimulated with vehicle, the synthetic TLR3 ligand, polyinosinic-polycytidylic acid (Poly I:C), a negative dsDNA control, or a positive control. Cytokine and chemokine production post-stimulation was measured by ELISA. The effects of E2 and P on TLR3 mRNA and protein expression were measured using Real Time RT-PCR and FACS analysis, respectively. RESULTS: Stimulation of TLR3-expressing cells with the synthetic TLR3 ligand, Poly I:C, resulted in the production of cytokines and chemokines important for endometrial function and regulation. Suppression of Poly I:C-induced cytokine and chemokine production by cells treated with 10^(-8) M E2, but not cells treated with 10^(-7) M P, was observed in endometrial epithelial cell lines expressing TLR3 and estrogen receptor alpha (ERalpha). The effects of E2 were not observed on cells which did not express ERalpha or in cells pre-treated with the ER antagonist, ICI 182, 780. Treatment with E2 did not affect TLR3 mRNA or protein expression. However, treatment with E2 did suppress cytokine and chemokine production resulting from TLR3 stimulation with Poly I:C, suggesting that E2 modulates TLR3 function. CONCLUSION: The data presented in this study are the first indication that E2 can markedly alter the innate immune response to dsRNA, providing a previously unreported process by which E2 can alter immune responses
Bimodality in Damped Lyman alpha Systems
We report evidence for a bimodality in damped Ly systems (DLAs). Using [C II]
158 mu cooling rates, lc, we find a distribution with peaks at lc=10^-27.4 and
10^-26.6 ergs s^-1 H^-1 separated by a trough at lc^crit ~= lc < 10^-27.0 ergs
s^-1 H^-1. We divide the sample into low cool DLAs with lc < lc^crit and high
cool DLAs with lc > lc^crit and find the Kolmogorv-Smirnov probabilities that
velocity width, metallicity, dust-to-gas ratio, and Si II equivalent width in
the two subsamples are drawn from the same parent population are small. All
these quantities are significantly larger in the high cool population, while
the H I column densities are indistinguishable in the two populations. We find
that heating by X-ray and FUV background radiation is insufficient to balance
the cooling rates of either population. Rather, the DLA gas is heated by local
radiation fields. The rare appearance of faint, extended objects in the Hubble
Ultra Deep Field rules out in situ star formation as the dominant
star-formation mode for the high cool population, but is compatible with in
situ star formation as the dominant mode for the low cool population. Star
formation in the high cool DLAs likely arises in Lyman Break galaxies. We
investigate whether these properties of DLAs are analogous to the bimodal
properties of nearby galaxies. Using Si II equivalent width as a mass
indicator, we construct bivariate distributions of metallicity, lc, and areal
SFR versus the mass indicators. Tentative evidence is found for correlations
and parallel sequences, which suggest similarities between DLAs and nearby
galaxies. We suggest that the transition-mass model provides a plausible
scenario for the bimodality we have found. As a result, the bimodality in
current galaxies may have originated in DLAs.Comment: Accepted for publication in the Astrophysical Journal 18 pages 14
figure
On the appearance of Eisenstein series through degeneration
Let be a Fuchsian group of the first kind acting on the hyperbolic
upper half plane , and let be the
associated finite volume hyperbolic Riemann surface. If is parabolic,
there is an associated (parabolic) Eisenstein series, which, by now, is a
classical part of mathematical literature. If is hyperbolic, then,
following ideas due to Kudla-Millson, there is a corresponding hyperbolic
Eisenstein series. In this article, we study the limiting behavior of parabolic
and hyperbolic Eisenstein series on a degenerating family of finite volume
hyperbolic Riemann surfaces. In particular, we prove the following result. If
corresponds to a degenerating hyperbolic element, then a
multiple of the associated hyperbolic Eisenstein series converges to parabolic
Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in
Commentarii Mathematici Helvetic
The microscopic detection of animal proteins in feeds
In the framework of the European Union funded research project STRATFEED for detection and identification of animal proteins in feeds, the microscopic method was optimized at several key steps and better documented. A check list was developed for uniform reporting. Characters of bone fragments, hairs, muscles and gills are fully documented. A so-called muscle ratio has been developed for the identification of muscle fibers at the level of vertebrate classes (mammals, birds and fishes). Both the improved protocol and the entire range of characters which can be observed, are documented in a Decision Support System called ARIES (Animal Remains Identification and Evaluation System). A second internet-based system called STRATFEED-DSS exclusively assists in identification of animal particles in feeds. A new strategy with microscopy as screening technique and either DNA or protein identification as confirmation technique is proposed. The advantages of this combination are the extremely low level of false negatives, low detection limits and the heat-resistant nature of microscopic detection, together with the possibility of a very specific identification of particles by one of the other methods
Human Endometrial Epithelial Cells Cyclically Express Toll-Like Receptor 3 (TLR3) and Exhibit TLR3-Dependent Responses to dsRNA
Toll-like receptor 3 (TLR3) responds to dsRNA, a product of most viral life cycles, and initiates production of proinflammatory and antiviral cytokines. The role of TLR3 in human mucosal immunity of the endometrium has not been examined. The effects of TLR3 ligation in endometrial epithelium could be significant as the endometrium is a significant site for viral entry and infection. Additionally, the cytokine milieu plays an essential role in normal functions of the endometrium such as uterine cycle progression, epithelial proliferation and shedding, and embryo implantation. In this study, we demonstrated cycle dependent expression of functional TLR3 in primary endometrial epithelial tissue and expression of intracellular TLR3 in human endometrial epithelial cell lines. We established that stimulation of TLR3-positive cell lines and primary human endometrial epithelial cells with dsRNA leads to TLR3-dependent expression of interleukin (IL)-6, IL-8, interferon (IFN)-inducible protein 10, RANTES, and IFN-β. These results indicate that the cytokine profile of human endometrial epithelial cells can be modified through TLR3 stimulation. Our findings suggest that TLR3 is involved in the immune responses of endometrial epithelial cells after exposure to dsRNA and has the potential to alter the cytokine milieu and influence the outcome and consequences of infection
Robin conditions on the Euclidean ball
Techniques are presented for calculating directly the scalar functional
determinant on the Euclidean d-ball. General formulae are given for Dirichlet
and Robin boundary conditions. The method involves a large mass asymptotic
limit which is carried out in detail for d=2 and d=4 incidentally producing
some specific summations and identities. Extensive use is made of the
Watson-Kober summation formula.Comment: 36p,JyTex, misprints corrected and a section on the massive case
adde
The effects of financialisation and financial development on investment: Evidence from firm-level data in Europe
In this paper we estimate the effects of financialization on physical investment in selected western European countries using panel data based on the balance-sheets of publicly listed non-financial companies (NFCs) supplied by Worldscope for the period 1995-2015. We find robust evidence of an adverse effect of both financial payments
(interests and dividends) and financial incomes on investment in fixed assets by the NFCs. This finding is robust for both the pool of all Western European firms and single country estimations. The negative impacts of financial incomes are non-linear with respect to the companies’ size: financial incomes crowd-out investment in large companies, and have a positive effect on the investment of only small, relatively more credit-constrained companies. Moreover, we find that a higher degree of financial development is associated with a stronger negative effect of financial incomes on companies’ investment. This finding challenges the common wisdom on ‘finance-growth nexus’. Our findings support the ‘financialization thesis’ that the increasing orientation of the non-financial sector towards financial activities is ultimately leading to lower physical investment, hence to stagnant or fragile growth, as well as long term stagnation in productivity
Decoupling Economic Growth and Energy Use. An Empirical Cross-Country Analysis for 10 Manufacturing Sectors
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