1,060 research outputs found
Self-administering arithmetic enrichment activities for the more rapid learner
Thesis (Ed.M.)--Boston Universit
Circadian and Ultradian Rhythms of Free Glucocorticoid Hormone Are Highly Synchronized between the Blood, the Subcutaneous Tissue, and the Brain
Total glucocorticoid hormone levels in plasma of various species, including humans, follow a circadian rhythm that is made up from an underlying series of hormone pulses. In blood most of the glucocorticoid is bound to corticosteroid-binding globulin and albumin, resulting in low levels of free hormone. Although only the free fraction is biologically active, surprisingly little is known about the rhythms of free glucocorticoid hormones. We used single-probe microdialysis to measure directly the free corticosterone levels in the blood of freely behaving rats. Free corticosterone in the blood shows a distinct circadian and ultradian rhythm with a pulse frequency of approximately one pulse per hour together with an increase in hormone levels and pulse height toward the active phase of the light/dark cycle. Similar rhythms were also evident in the subcutaneous tissue, demonstrating that free corticosterone rhythms are transferred from the blood into peripheral target tissues. Furthermore, in a dual-probe microdialysis study, we demonstrated that the circadian and ultradian rhythms of free corticosterone in the blood and the subcutaneous tissue were highly synchronized. Moreover, free corticosterone rhythms were also synchronous between the blood and the hippocampus. These data demonstrate for the first time an ultradian rhythm of free corticosterone in the blood that translates into synchronized rhythms of free glucocorticoid hormone in peripheral and central tissues. The maintenance of ultradian rhythms across tissue barriers in both the periphery and the brain has important implications for research into aberrant biological rhythms in disease and for the development of improved protocols for glucocorticoid therapy
Absorption of dark matter by a supermassive black hole at the Galactic center: role of boundary conditions
The evolution of the dark matter distribution at the Galactic center is
analyzed, which is caused by the combination of gravitational scattering on
Galactic bulge stars and absorption by a supermassive black hole at the center
of the bulge. Attention is focused on the boundary condition on the black hole.
It is shown that its form depends on the energy of dark matter particles. The
modified flux of dark matter particles onto the black hole is calculated.
Estimates of the amount of dark matter absorbed show that the fraction of dark
matter in the total mass of the black hole may be significant. The density of
dark matter at the central part of the bulge is calculated. It is shown that
recently observed gamma radiation from the Galactic center can be attributed to
the annihilation of dark matter with this density.Comment: 5 page
Adhesion Molecule Targeted Therapy for Non-Infectious Uveitis
Non-infectious uveitis (NIU) is an inflammatory eye disease initiated via CD4+ T-cell activation and transmigration, resulting in focal retinal tissue damage and visual acuity disturbance. Cell adhesion molecules (CAMs) are activated during the inflammatory process to facilitate the leukocyte recruitment cascade. Our review focused on CAM-targeted therapies in experimental autoimmune uveitis (EAU) and NIU. We concluded that CAM-based therapies have demonstrated benefits for controlling EAU severity with decreases in immune cell migration, especially via ICAM-1/LFA-1 and VCAM-1/VLA-4 (integrin) pathways. P-selectin and E-selectin are more involved specifically in uveitis related to vasculitis. These therapies have potential clinical applications for the development of a more personalized and specific treatment. Localized therapies are the future direction to avoid serious systemic side effects
Clinical and molecular features associated with cystic visceral lesions in von hippel-lindau disease.
Von Hippel-Lindau (VHL) is an uncommon oncogenic disorder which occurs as a result of genetic mutations on chromosome 3p. Retinal capillary haemangiomas and CNS haemangioblastomas have been well-characterised in genotypic-phenotypic analyses, but cystic visceral lesions are less common and have been less frequently studied. The aim of this study was to perform genotypic and phenotypic analysis of a cohort of VHL patients that developed cystic visceral lesions to determine whether their genotype differs from that seen in other manifestations of VHL and whether the ocular manifestations differ.This study reports a prospective case series of twenty-one patients identified from the Hammersmith Hospital Genetics Service database as having VHL mutations. Patients underwent regular ocular and systemic screening as well as genotypic analysis. The main outcome measures were the development of VHL lesions, either ocular or systemic.Cystic visceral lesions were detected in six of the 21 patients from the clinic (29%). These included renal cysts in four patients, pancreatic cysts in three patients, and an epididymal cystadenoma in one patient. Renal cysts were not associated with any specific genotype. Pancreatic cysts appeared to occur in association with VHL gene deletions and all developed CNS haemangioblastomas. Only one patient developed ocular manifestations, which occurred in this patient in the form of two retinal capillary haemangiomas.VHL gene deletions appeared to be associated with pancreatic cysts and the development of CNS haemangioblastomas. Ocular manifestations are uncommon in this group of patients
A new numerical method to construct binary neutron star initial data
We present a new numerical method for the generation of binary neutron star
initial data using a method along the lines of the the Wilson-Mathews or the
closely related conformal thin sandwich approach. Our method uses six different
computational domains, which include spatial infinity. Each domain has its own
coordinates which are chosen such that the star surfaces always coincide with
domain boundaries. These properties facilitate the imposition of boundary
conditions. Since all our fields are smooth inside each domain, we are able to
use an efficient pseudospectral method to solve the elliptic equations
associated with the conformal thin sandwich approach. Currently we have
implemented corotating configurations with arbitrary mass ratios, but an
extension to arbitrary spins is possible. The main purpose of this paper is to
introduce our new method and to test our code for several different
configurations.Comment: 18 pages, 8 figures, 1 tabl
Формирование творческой речевой активности дошкольников с функциональными нарушениями зрения
Рассматриваются основные этапы формирования навыков творческого рассказывания у дошкольников с функциональными нарушениями зрения, перечисляются эффективные приемы стимулирования творческой речевой активности дошкольников с ослабленным зрение
Extended Quintessence with non-minimally coupled phantom scalar field
We investigate evolutional paths of an extended quintessence with a
non-minimally coupled phantom scalar field to the Ricci curvature. The
dynamical system methods are used to investigate typical regimes of dynamics at
the late time. We demonstrate that there are two generic types of evolutional
scenarios which approach the attractor (a focus or a node type critical point)
in the phase space: the quasi-oscillatory and monotonic trajectories approach
to the attractor which represents the FRW model with the cosmological constant.
We demonstrate that dynamical system admits invariant two-dimensional
submanifold and discussion that which cosmological scenario is realized depends
on behavior of the system on the phase plane . We formulate
simple conditions on the value of coupling constant for which
trajectories tend to the focus in the phase plane and hence damping
oscillations around the mysterious value . We describe this condition in
terms of slow-roll parameters calculated at the critical point. We discover
that the generic trajectories in the focus-attractor scenario come from the
unstable node. It is also investigated the exact form of the parametrization of
the equation of state parameter (directly determined from dynamics)
which assumes a different form for both scenarios.Comment: revtex4, 15 pages, 9 figures; (v2) published versio
Lattice determination of the Decay Amplitude
We describe the computation of the amplitude A_2 for a kaon to decay into two
pions with isospin I=2. The results presented in the letter Phys.Rev.Lett. 108
(2012) 141601 from an analysis of 63 gluon configurations are updated to 146
configurations giving Re GeV and Im
GeV. Re is in good agreement with the experimental result, whereas the
value of Im was hitherto unknown. We are also working towards a direct
computation of the amplitude but, within the
standard model, our result for Im can be combined with the experimental
results for Re, Re and to give
ImRe . Our result for Im\, implies
that the electroweak penguin (EWP) contribution to
is Re.Comment: 59 pages, 11 figure
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