150 research outputs found
A characterization of Schauder frames which are near-Schauder bases
A basic problem of interest in connection with the study of Schauder frames
in Banach spaces is that of characterizing those Schauder frames which can
essentially be regarded as Schauder bases. In this paper, we give a solution to
this problem using the notion of the minimal-associated sequence spaces and the
minimal-associated reconstruction operators for Schauder frames. We prove that
a Schauder frame is a near-Schauder basis if and only if the kernel of the
minimal-associated reconstruction operator contains no copy of . In
particular, a Schauder frame of a Banach space with no copy of is a
near-Schauder basis if and only if the minimal-associated sequence space
contains no copy of . In these cases, the minimal-associated
reconstruction operator has a finite dimensional kernel and the dimension of
the kernel is exactly the excess of the near-Schauder basis. Using these
results, we make related applications on Besselian frames and near-Riesz bases.Comment: 12 page
Self-energy and Self-force in the Space-time of a Thick Cosmic String
We calculate the self-energy and self-force for an electrically charged
particle at rest in the background of Gott-Hiscock cosmic string space-time. We
found the general expression for the self-energy which is expressed in terms of
the matrix of the scattering problem. The self-energy continuously falls
down outward from the string's center with maximum at the origin of the string.
The self-force is repulsive for an arbitrary position of the particle. It tends
to zero in the string's center and also far from the string and it has a
maximum value at the string's surface. The plots of the numerical calculations
of the self-energy and self-force are shown.Comment: 15 pages, 4 Postscript figures, ReVTe
Complete Classification of the String-like Solutions of the Gravitating Abelian Higgs Model
The static cylindrically symmetric solutions of the gravitating Abelian Higgs
model form a two parameter family. In this paper we give a complete
classification of the string-like solutions of this system. We show that the
parameter plane is composed of two different regions with the following
characteristics: One region contains the standard asymptotically conic cosmic
string solutions together with a second kind of solutions with Melvin-like
asymptotic behavior. The other region contains two types of solutions with
bounded radial extension. The border between the two regions is the curve of
maximal angular deficit of .Comment: 12 pages, 4 figure
Retromer binds the FANSHY sorting motif in SorLA to regulate amyloid precursor protein sorting and processing
sorLA is a sorting receptor for amyloid precursor protein (APP) genetically linked to Alzheimer's disease (AD). Retromer, an adaptor complex in the endosome-to-Golgi retrieval pathway, has been implicated in APP transport because retromer deficiency leads to aberrant APP sorting and processing and levels of retromer proteins are altered in AD. Here we report that sorLA and retromer functionally interact in neurons to control trafficking and amyloidogenic processing of APP. We have identified a sequence (FANSHY) in the cytoplasmic domain of sorLA that is recognized by the VPS26 subunit of the retromer complex. Accordingly, we characterized the interaction between the retromer complex and sorLA and determined the role of retromer on sorLA-dependent sorting and processing of APP. Mutations in the VPS26 binding site resulted in receptor redistribution to the endosomal network, similar to the situation seen in cells with VPS26 knockdown. The sorLA mutant retained APP-binding activity but, as opposed to the wild-type receptor, misdirected APP into a distinct non-Golgi compartment, resulting in increased amyloid processing. In conclusion, our data provide a molecular link between reduced retromer expression and increased amyloidogenesis as seen in patients with sporadic AD
Classification of temporomandibular joint sounds based upon their reduced interference distribution
Temporomandibular joint (TMJ) sounds were recorded in 98 orthodontic retention patients, mean age 19 ± 8–6 (s.d.) years, by interview, auscultation and electronic recording. Sounds were found by auscultation in 41% and by interview in 32% of the subjects, more often in females than in males (P ≤ 0.05). A new method for time-frequency analysis, the reduced interference distribution (RID), was used to classify the electronic sound recordings into five subclasses, RID types 1–5, based upon location and number of their energy peaks. RID types 1–3 had a few energy peaks close in time. RID types 4–5, typical of subjects with crepitation, had multiple energy peaks occurring close in time for a period of 20–300 ms. RID type 1, found in 45% of the subjects, typical of patients with clicking, had its dominant energy peak located in a frequency range ≤600 Hz and was significantly more common in the female than in the male subjects (P≤ 0.01). RID type 2, found in 68% of the subjects, with the dominant peak in the range 600–1200 Hz, and RID type 3, found in 38% of the subjects, with the peak in the frequency range >1200 Hz, were found to have a similar gender distribution. RID type 4, found in 49% of the subjects, had the energy peaks distributed in the frequency range ≤600 Hz. RID type 5, found in 43% of the subjects, more often in females than in males (P≤ 0.05), had the peaks distributed over the whole frequency range from about 30 Hz up to about 3000 Hz. In conclusion, a more detailed classification could be made of the TMJ sounds by displaying the RIDs than by auscultation. This suggests that RID classification methods may provide a means for differentiating sounds indicating different types of pathology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74694/1/j.1365-2842.1996.tb00809.x.pd
Recent Advances in Modeling Stellar Interiors
Advances in stellar interior modeling are being driven by new data from
large-scale surveys and high-precision photometric and spectroscopic
observations. Here we focus on single stars in normal evolutionary phases; we
will not discuss the many advances in modeling star formation, interacting
binaries, supernovae, or neutron stars. We review briefly: 1) updates to input
physics of stellar models; 2) progress in two and three-dimensional evolution
and hydrodynamic models; 3) insights from oscillation data used to infer
stellar interior structure and validate model predictions (asteroseismology).
We close by highlighting a few outstanding problems, e.g., the driving
mechanisms for hybrid gamma Dor/delta Sct star pulsations, the cause of giant
eruptions seen in luminous blue variables such as eta Car and P Cyg, and the
solar abundance problem.Comment: Proceedings for invited talk at conference High Energy Density
Laboratory Astrophysics 2010, Caltech, March 2010, submitted for special
issue of Astrophysics and Space Science; 7 pages; 5 figure
A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site
This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≥3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda
Thermal Evolution and Magnetic Field Generation in Terrestrial Planets and Satellites
Blood pressure-lowering effects of nifedipine/candesartan combinations in high-risk individuals: Subgroup analysis of the DISTINCT randomised trial
The DISTINCT study (reDefining Intervention with Studies Testing Innovative Nifedipine GITS - Candesartan Therapy) investigated the efficacy and safety of nifedipine GITS/candesartan cilexetil combinations vs respective monotherapies and placebo in patients with hypertension. This descriptive sub-analysis examined blood pressure (BP)-lowering effects in high-risk participants, including those with renal impairment (estimated glomerular filtration rate<90 ml min-1, n=422), type 2 diabetes mellitus (n=202), hypercholesterolaemia (n=206) and cardiovascular (CV) risk factors (n=971), as well as the impact of gender, age and body mass index (BMI). Participants with grade I/II hypertension were randomised to treatment with nifedipine GITS (N) 20, 30, 60 mg and/or candesartan cilexetil (C) 4, 8, 16, 32 mg or placebo for 8 weeks. Mean systolic BP and diastolic BP reductions after treatment in high-risk participants were greater, overall, with N/C combinations vs respective monotherapies or placebo, with indicators of a dose-response effect. Highest rates of BP control (ESH/ESC 2013 guideline criteria) were also achieved with highest doses of N/C combinations in each high-risk subgroup. The benefits of combination therapy vs monotherapy were additionally observed in patient subgroups categorised by gender, age or BMI. All high-risk participants reported fewer vasodilatory adverse events in the pooled N/C combination therapy than the N monotherapy group. In conclusion, consistent with the DISTINCT main study outcomes, high-risk participants showed greater reductions in BP and higher control rates with N/C combinations compared with respective monotherapies and lesser vasodilatory side-effects compared with N monotherapy
Geofungos no CĂłrrego do Sapateiro, Parque Municipal do Ibirapuera, SĂŁo Paulo, SP, Brasil
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