1,085 research outputs found
Singular normal form for the Painlev\'e equation P1
We show that there exists a rational change of coordinates of Painlev\'e's P1
equation and of the elliptic equation after which these
two equations become analytically equivalent in a region in the complex phase
space where and are unbounded. The region of equivalence comprises all
singularities of solutions of P1 (i.e. outside the region of equivalence,
solutions are analytic). The Painlev\'e property of P1 (that the only movable
singularities are poles) follows as a corollary. Conversely, we argue that the
Painlev\'e property is crucial in reducing P1, in a singular regime, to an
equation integrable by quadratures
Ionization in damped time-harmonic fields
We study the asymptotic behavior of the wave function in a simple one
dimensional model of ionization by pulses, in which the time-dependent
potential is of the form ,
where is the Dirac distribution. We find the ionization probability in
the limit for all and . The long pulse limit is
very singular, and, for , the survival probability is , much larger than , the one in the abrupt transition
counterpart, where
is the Heaviside function
Decay versus survival of a localized state subjected to harmonic forcing: exact results
We investigate the survival probability of a localized 1-d quantum particle
subjected to a time dependent potential of the form with
or . The particle is
initially in a bound state produced by the binding potential . We
prove that this probability goes to zero as for almost all values
of , , and . The decay is initially exponential followed by a
law if is not close to resonances and is small; otherwise
the exponential disappears and Fermi's golden rule fails. For exceptional sets
of parameters and the survival probability never decays to zero,
corresponding to the Floquet operator having a bound state. We show similar
behavior even in the absence of a binding potential: permitting a free particle
to be trapped by harmonically oscillating delta function potential
Differing roles of autophagy in HIV-associated neurocognitive impairment and encephalitis with implications for morphine co-exposure
We investigated the role of autophagy in HIV-infected subjects with neurocognitive impairment (NCI) ± HIV encephalitis (HIVE), many of which had a history of polysubstance abuse/dependence, using post-mortem brain tissues to determine whether differences in autophagy related factors may be more associated with NCI or NCI-encephalitis. Using qRT-PCR, we detected significant differences in gene expression levels with SQSTM1, LAMP1 higher in HIV-infected subjects without NCI while ATG5, SQSTM1 were then lower in HIV infection/NCI and ATG7, SQSTM1 being higher in NCI-HIVE. Immunohistochemical labeling of these autophagy associated proteins (also including Beclin 1 and LC3B) in Iba1-positive microglial cells showed generally higher immunoreactivity in the NCI and NCI-HIVE groups with more focal vs. diffuse patterns of expression in the NCI-HIVE group. Furthermore, analysis of microarray data from these same subjects found significantly higher levels of LAMP1 in NCI-HIVE compared to uninfected subjects in the basal ganglia. Finally, we tested the effect of supernatant from HIV-1-infected microglia and HIV-1 Tat protein in combination with morphine on neurons in vitro and found opposing events with both significant inhibition of autophagic flux and reduced dendrite length for morphine and supernatant treatment while Tat and morphine exposure resulted in lower autophagic activity at an earlier time point and higher levels in the later. These results suggest autophagy genes and their corresponding proteins may be differentially regulated at the transcriptional, translational, and post-translational levels in the brain during various stages of the HIV disease and that infected individuals exposed to morphine can experience mixed signaling of autophagic activity which could lead to more severe NCI than those without opioid use
Cohomological BRST aspects of the massless tensor field with the mixed symmetry (k,k)
The main BRST cohomological properties of a free, massless tensor field that
transforms in an irreducible representation of GL(D,R), corresponding to a
rectangular, two-column Young diagram with k>2 rows are studied in detail. In
particular, it is shown that any non-trivial co-cycle from the local BRST
cohomology group H(s|d) can be taken to stop either at antighost number (k+1)
or k, its last component belonging to the cohomology of the exterior
longitudinal derivative H(gamma) and containing non-trivial elements from the
(invariant) characteristic cohomology H^{inv}(delta|d).Comment: Latex, 50 pages, uses amssym
Hamiltonian BRST deformation of a class of n-dimensional BF-type theories
Consistent Hamiltonian interactions that can be added to an abelian free
BF-type class of theories in any n greater or equal to 4 spacetime dimensions
are constructed in the framework of the Hamiltonian BRST deformation based on
cohomological techniques. The resulting model is an interacting field theory in
higher dimensions with an open algebra of on-shell reducible first-class
constraints. We argue that the Hamiltonian couplings are related to a natural
structure of Poisson manifold on the target space.Comment: 27 pages, uses JHEP3.cl
Evolution of the one-phonon 2(1,ms)(+) mixed-symmetry state in N=80 isotones as a local measure for the proton-neutron quadrupole interaction
An inverse kinematics Coulomb excitation experiment was performed to obtain absolute E2 and M1 transition strengths in 134Xe. The measured transition strengths indicate that the 23+ state of 134Xe is the dominant fragment of the one-phonon 21, ms+ mixed-symmetry state. Comparing the energy of the 21, ms+ mixed-symmetry state in 134Xe to that of the 21, ms+ levels in the N = 80 isotonic chain indicates that the separation in energy between the fully-symmetric 21+ state and the 21, ms+ level increases as a function of the number of proton pairs outside the Z = 50 shell closure. This behavior can be understood as resulting from the mixing of the basic components of a two-fluid quantum system. A phenomenological fit based on this concept was performed. It provides the first experimental estimate of the strength of the proton-neutron quadrupole interaction derived from nuclear collective states with symmetric and antisymmetric nature
Histological changes in the vulva and vagina from ovariectomised rats undergoing oestrogen treatment
Background: The purpose of this study was to assess the histological changes occurring in the vagina and vulva in ovariectomised female rats, as well as the response to the administration of injectable oestrogens.
Material and methods: We used 30 female Wistar white rats, distributed as follows: group 1 — the control group, group 2 — the operated but untreated rats, and groups 3, 4 and 5 — operated rats, to which oestrogenic treatment was administered (Estradiol, Estradurin, Sintofolin) at a dosage of 0.2 mg/rat/day. After 14 days of treatment, all animals were sacrificed and vaginal and vulvar biopsies were taken from all groups.
Results: In group 2, we encountered structural changes of the vaginal mucosa, with severe atrophy and alterations in the thickness of the vagina and vulva. In groups 3, 4 and 5 we found marked hyperplasia of the vaginal and vulvar epithelium, eosinophilic and mast cell infiltration in the chorion.
Conclusions: Our study proves that the histopathological changes during anoestrus after administration of oestrogens are cell hyperplasia, thickening of the superficial mucosal layer, eosinophilic and mast cells infiltrations, and chorionic congestion. Furthermore, we demonstrated that Estradiol therapy induces the most evident histological changes when compared to synthetic oestrogens such as Estradurin or Sintofolin.
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Integrated care pilot in north-west London: a mixed methods evaluation
Introduction: This paper provides the results of a year-long evaluation of a large-scale integrated care pilot in north-west London. The pilot aimed to integrate care across primary, acute, community, mental health and social care for people with diabetes and/or those aged 75+ through care planning, multidisciplinary case reviews, information sharing and project management support.
Methods: The evaluation team conducted qualitative studies of change at organisational, clinician and patient levels (using interviews, focus groups and a survey); and quantitative analysis of change in service use and patient-level clinical outcomes (using patient-level datasets and a matched control study).
Results: The pilot had successfully engaged provider organisations, created a shared strategic vision and established governance structures. However, the engagement of clinicians was variable and there was no evidence to date of significant reductions in emergency admissions. There was some evidence of changes in care processes.
Conclusion: Although the pilot has demonstrated the beginnings of large-scale change, it remains in the early stages and faces significant challenges as it seeks to become sustainable for the longer term. It is critical that National Health Service managers and clinicians have realistic expectations of what can be achieved in a relatively short period of time
Transition probabilities in the X(5) candidate Ba
To investigate the possible X(5) character of 122Ba, suggested by the ground
state band energy pattern, the lifetimes of the lowest yrast states of 122Ba
have been measured, via the Recoil Distance Doppler-Shift method. The relevant
levels have been populated by using the 108Cd(16O,2n)122Ba and the
112Sn(13C,3n)122Ba reactions. The B(E2) values deduced in the present work are
compared to the predictions of the X(5) model and to calculations performed in
the framework of the IBA-1 and IBA-2 models
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