214 research outputs found
On the range of unbounded vector valued measure
Liapunov theorem for range of unbound vector valued measur
Existence theorems for optimal problems with vector valued cost function
Existence theorems for optimal control problems with vector valued cost functio
Variable Stars in the Globular Cluster M5. Application of the Image Subtraction Method
We present -band light curves of 61 variables from the core of the
globular cluster M5 obtained using a newly developed image subtraction method
(ISM). Four of these variables were previously unknown. Only 26 variables were
found in the same field using photometry obtained with DoPHOT software. Fourier
parameters of the ISM light curves have relative errors up to 20 times smaller
than parameters measured from DoPHOT photometry. We conclude that the new
method is very promising for searching for variable stars in the cores of the
globular clusters and gives very accurate relative photometry with quality
comparable to photometry obtained by HST. We also show that the variable V104
is not an eclipsing star as has been suggested, but is an RRc star showing
non-radial pulsations.Comment: submitted to MNRAS, 9 pages, 4 figure
On approximate solutions of semilinear evolution equations
A general framework is presented to discuss the approximate solutions of an
evolution equation in a Banach space, with a linear part generating a semigroup
and a sufficiently smooth nonlinear part. A theorem is presented, allowing to
infer from an approximate solution the existence of an exact solution.
According to this theorem, the interval of existence of the exact solution and
the distance of the latter from the approximate solution can be evaluated
solving a one-dimensional "control" integral equation, where the unknown gives
a bound on the previous distance as a function of time. For example, the
control equation can be applied to the approximation methods based on the
reduction of the evolution equation to finite-dimensional manifolds: among
them, the Galerkin method is discussed in detail. To illustrate this framework,
the nonlinear heat equation is considered. In this case the control equation is
used to evaluate the error of the Galerkin approximation; depending on the
initial datum, this approach either grants global existence of the solution or
gives fairly accurate bounds on the blow up time.Comment: 33 pages, 10 figures. To appear in Rev. Math. Phys. (Shortened
version; the proof of Prop. 3.4. has been simplified
Dwarf Nova V1040 Centauri and Variable Stars in its Vicinity
We present the results of a photometric campaign of the dwarf nova V1040 Cen.
The light curve shows two normal outbursts with recurrence time ~ 40 days and
amplitude ~ 2.5 mag. Quiescence data show oscillations with periods in the
range ~ 0.1 days (2.4 h) to ~ 0.5 days (12 h) of unknown origin. We measured
the orbital period of V1040 Cen to be P_orb=0.060458(80) days (1.451+-0.002 h).
Based on the M_v-P_orb relation we found the distance of V1040 Cen to be
137+-31 pc. In this paper we also report the detection of eleven new variable
stars in the field of the monitored dwarf nova.Comment: 7 figures and 2 tables, accepted for publication in Acta Astronomic
A double-blind, placebo-controlled, phase II, randomized study of lovastatin therapy in the treatment of mildly active rheumatoid arthritis
© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. 3-hydroxy-3-methylglutaryl coenzyme-A (HMG Co-A) reductase inhibitors (statins) are standard treatment for hyperlipidaemia. In addition to lipid-lowering abilities, statins exhibit multiple anti-inflammatory effects. The objectives of this study were to determine whether treatment of patients with RA with lovastatin decreased CRP or reduced disease activity. Methods: We conducted a randomized double-blind placebo-controlled 12 week trial of lovastatin vs placebo in 64 RA patients with mild clinical disease activity but an elevated CRP. The primary efficacy end point was the reduction in mean log CRP. Secondary end points included disease activity, RF and anti-CCP antibody titres. Mechanistic end points included levels of serum cytokines. Safety was assessed; hepatic and muscle toxicities were of particular interest. Results: Baseline features were similar between groups. No significant difference in mean log CRP reduction between the two groups was observed, and disease activity did not change from baseline in either treatment group. Mechanistic analyses did not reveal significant changes in any biomarkers. A post hoc analysis of subjects not using biologic therapy demonstrated a significantly greater proportion achieving ≥20% reduction in CRP from baseline in the lovastatin group compared with placebo (P-value = 0.007). No difference was observed in subjects receiving biologics. Lovastatin was well tolerated with no serious safety concerns. Conclusion: This study showed no anti-inflammatory or clinical effects on RA disease activity after 12 weeks of treatment with lovastatin. Lovastatin had a modest effect on CRP in subjects not using biologics, suggesting statins may be anti-inflammatory in selected patients. Trial registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT00302952
The Dwarf Novae of Shortest Period
We present observations of the dwarf novae GW Lib, V844 Her, and DI UMa.
Radial velocities of H-alph yield orbital periods of 0.05332 +- 0.00002 d (=
76.78 m) for GW Lib and and 0.054643 +- 0.000007 d (= 78.69 m) for V844 Her.
Recently, the orbital period of DI UMa was found to be only 0.054564 +-
0.000002 d (= 78.57 m) by Fried et al. (1999), so these are the three shortest
orbital periods among dwarf novae with normal-abundance secondaries.
GW Lib has attracted attention as a cataclysmic binary showing apparent ZZ
Ceti-type pulsations of the white dwarf primary. Its spectrum shows sharp
Balmer emission flanked by strong, broad Balmer absorption, indicating a
dominant contribution by white-dwarf light. Analysis of the Balmer absorption
profiles is complicated by the unknown residual accretion luminosity and lack
of coverage of the high Balmer lines. Our best-fit model atmospheres are
marginally hotter than the ZZ Ceti instability strip, in rough agreement with
recent ultraviolet results from HST. The spectrum and outburst behavior of GW
Lib make it a near twin of WZ Sge, and we estimate it to have a quiescent V
absolute magnitude 12. Comparison with archival data reveals proper motion of
65 +- 12 mas/yr.
The mean spectrum of V844 Her is typical of SU UMa dwarf novae. We detected
superhumps in the 1997 May superoutburst with superhump period = 0.05597 +-
0.00005 d. The spectrum of DI UMa appears normal for a dwarf nova near minimum
light.
These three dwarf novae have nearly identical short periods but completely
dissimilar outburst characteristics. We discuss possible implications.Comment: Accepted for publication in Publications of the Astronomical Society
of the Pacific; 16 pages, 6 figure
How much of the invader’s genetic variability can slip between our fingers? A case study of secondary dispersal of Poa annua on King George Island (Antarctica)
We studied an invasion of Poa annua on King George Island (Maritime Antarctic). The
remoteness of this location, its geographic isolation, and its limited human traffic provided
an opportunity to trace the history of an invasion of the species. Poa annua was
recorded for the first time at H. Arctowski Polish Antarctic Station in the austral summer
of 1985/6. In 2008/9, the species was observed in a new locality at the Ecology
Glacier Forefield (1.5 km from “Arctowski”). We used AFLP to analyze the genetic
differences among three populations of P. annua: the two mentioned above (Station
and Forefield) and the putative origin of the introduction, Warsaw (Poland). There was
38% genetic variance among the populations. Pairwise ФPT was 0.498 between the
Forefield and Warsaw populations and 0.283 between Warsaw and Station. There were
15 unique bands in the Warsaw population (frequency from 6% to 100%) and one in
the Station/Forefield populations (which appears in all analyzed individuals from both
populations). The Δ(K) parameter indicated two groups of samples: Warsaw/Station
and Forefield. As indicated by Fu’s Fs statistics and an analysis of mismatch distribution,
the Forefield population underwent a bottleneck and/or founder effect. The
Forefield population was likely introduced by secondary dispersal from the Station
population
A multi-color and Fourier study of RR Lyrae variables in the globular cluster NGC 5272 (M3)
We have performed a detailed study of the pulsational and evolutionary
characteristics of 133 RR Lyrae stars in the globular cluster NGC5272 (M3)
using highly accurate BVI data taken on 5 separate epochs. M3 seems to contain
no less than ~32% of Blazhko stars, and the occurrence and characteristics of
the Blazhko effect have been analyzed in detail. We have identified a good
number (~ 14%) of overluminous RR Lyrae stars that are likely in a more
advanced evolutionary stage off the Zero Age Horizontal Branch (ZAHB). Physical
parameters (i.e. temperature, luminosity, mass) have been derived from (B--V)
colors and accurate color-temperature calibration, and compared with Horizontal
Branch evolutionary models and with the requirements of stellar pulsation
theory. Additional analysis by means of Fourier decomposition of the V light
curves confirms, as expected, that no metallicity spread is present in M3.
Evolution off the ZAHB does not affect [Fe/H] determinations, whereas Blazhko
stars at low amplitude phase do affect [Fe/H] distributions as they appear more
metal-rich. Absolute magnitudes derived from Fourier coefficients might provide
useful average estimates for groups of stars, if applicable, but do not give
reliable {\em individual} values. Intrinsic colors derived from Fourier
coefficients show significant discrepancies with the observed ones, hence the
resulting temperatures and temperature-related parameters are unreliable.Comment: 86 pages, 19 figures, 13 tables, in press A
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