6,800 research outputs found
The Cheshire Cat Bag Model: Color Anomaly and Properties
We show that color can leak from a QCD bag if we allow for pseudoscalar
isoscalar singlet () coupling at the surface. To enforce total
confinement of color an additional boundary term is suggested. New relations
between the mass and decay constant and the QCD gluon condensates are
derived and compared with the empirical parameters.Comment: 7 pages, LaTeX, Nordita - 92/68
Phase Space dynamics of triaxial collapse: Joint density-velocity evolution
We investigate the dynamics of triaxial collapse in terms of eigenvalues of
the deformation tensor, the velocity derivative tensor and the gravity Hessian.
Using the Bond-Myers model of ellipsoidal collapse, we derive a new set of
equations for the nine eigenvalues and examine their dynamics in phase space.
The main advantage of this form is that it eliminates the complicated elliptic
integrals that appear in the axes evolution equations and is more natural way
to understand the interplay between the perturbations.
This paper focuses on the density-velocity dynamics. The Zeldovich
approximation implies that the three tensors are proportional; the
proportionality constant is set by demanding `no decaying modes'. We extend
this condition into the non-linear regime and find that the eigenvalues of the
gravity Hessian and the velocity derivative tensor are related as , where the triaxiality parameter . This is a {\it new universal relation} holding true
over all redshifts and a range of mass scales to within a few percent accuracy.
The mean density-velocity divergence relation at late times is close to linear,
indicating that the dynamics is dictated by collapse along the largest
eigendirection. This relation has a scatter, which we show, is intimately
connected to the velocity shear. Finally, as an application, we compute the
PDFs of the two variables and compare with other forms in the literature.Comment: 23 pages (16 text+appendix); 11 figures, revised version accepted for
publication in MNRA
Anti-TNF-alpha therapy induces a distinct regulatory T cell population in patients with rheumatoid arthritis via TGF-beta
The induction of regulatory T (T reg) cells holds considerable potential as a treatment for autoimmune diseases. We have previously shown that CD4(+)CD25(hi) T reg cells isolated from patients with active rheumatoid arthritis (RA) have a defect in their ability to suppress proinflammatory cytokine production by CD4(+)CD25(-) T cells. This defect, however, was overcome after anti-tumor necrosis factor (TNF)-alpha antibody (infliximab) therapy. Here, we demonstrate that infliximab therapy gives rise to a CD4(+)CD25(hi)FoxP3(+) T reg cell population, which mediates suppression via transforming growth factor (TGF)-beta and interleukin 10, and lacks CD62L expression, thereby distinguishing this T reg cell subset from natural T reg cells present in healthy individuals and patients with active RA. In vitro, infliximab induced the differentiation of CD62L(-) T reg cells from CD4(+)CD25(-) T cells isolated from active RA patients, a process dependent on TGF-alpha. In spite of the potent suppressor capacity displayed by this CD62L(-) T reg cell population, the natural CD62L(+) T reg cells remained defective in infliximab-treated patients. These results suggest that anti-TNF-alpha therapy in RA patients generates a newly differentiated population of T reg cells, which compensates for the defective natural T reg cells. Therefore, manipulation of a proinflammatory environment could represent a therapeutic strategy for the induction of T reg cells and the restoration of tolerance
Case reports for embryo banking: for women who want their own
Out of the many challenges in management of female factor infertility, poor responders and low response to stimulation in aged and even younger women, seems to be a common problem. It is very difficult to offer one particular management strategy or treatment protocol for optimum outcome in this group of women of poor responders. In a low resource set up, IVF (In vitro Fertilization) specialist doctors usually face a challenge in treating women with poor/ low ovarian reserve as ovum / gamete donation is considered as a taboo in various sections of society even today. Hence women insist on having an offspring of "their own" and vehemently deny ovum / gamete donations. In this article we discuss 2 cases of poor ovarian reserve retrospectively, who underwent multiple cycles of controlled ovarian hyperstimulation for embryo banking and ultimately achieved pregnancy. Both patients achieved pregnancy with the method of embryo banking. Embryo banking should be considered and discussed. Various articles have discussed the advantages and disadvantages of embryo banking or even oocytes accumulation. The advantages of this technique is patients with poor/low ovarian reserve get a chance to be pregnant with their own oocytes and also have a chance for vitrification of residual embryos. Another advantage in such patients is that the embryos can undergo PGS (Preimplantation Genetic Screening) techniques in cases of suspected genetic disorders. The disadvantage in a low resource set up like India is the cost of the treatment. Nevertheless, embryo banking and accumulation of oocytes should be given as an option for treatment of poor/ low ovarian reserve and could be considered as a ray of hope for all future mothers hoping for a child of "their own"
100 years of tropical bryophyte and lichen ecology : a bibliographic guide to the literature from 1901 - 2000
A list of 401 citations pertaining to the ecology of tropical bryophytes and lichens is presented. The bibliography includes publications addressing the biology, ecology, natural history, and physiology of bryophytes and lichens, but generally eschews taxonomic and floristic papers. All citations have been verified, unless denoted with an asterisk (*). An appendix that groups citations by category is provided
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