822 research outputs found
The Demographic Dimensions of Divorce: The Case of Finland
Any demographic event such as birth, death, marriage, and divorce may be registered and studied with respect to various demographic dimensions; these are most prominently age and time but also duration of marriage, time since last birth, etc. Fertility, mortality, and nuptiality are all considered to depend primarily on age. Divorce has traditionally been studied with respect to marital duration.
This paper uses a multi-dimensional perspective to study the phenomenon of divorce. It is made possible by the availability of a unique data set from the Finnish Population Register that provides cross-classified information on several demographic dimensions of divorce. The study yields intriguing results that give a quite different picture than conventional one- and two-dimensional perspectives
New light curves and ephemeris for the close eclipsing binary V963 PER
We have obtained CCD photometry in 2010-11 of V963 Per (=GSC3355 0394), which
is a recently identified close binary star with unequal eclipse depths. The
seven new eclipse timings yield an improved ephemeris, but we caution that
secondary eclipse can be affected by variation of the light curve. This
variation seems to be on a monthly timescale at the few percent level.Comment: 6 pages, 3 figure
Mozambique's Future: Modeling Population and Sustainable Development Challenges
What are the prospects for sustainable development over the next 20 years in Mozambique? Although it looks as if much of the development prospects are determined by such inherently unpredictable events as war, peace, and weather calamities, there are also many changes and patterns which have a long-term stability and which change only slowly over time. For example, socio-demographic changes, such as labor force skills, and population health have a long momentum. These are very important indicators for the economic development potential of a country. Also, although it is impossible to predict a particular year of heavy rains or droughts, there are long time series of weather from which we can calculate the country's vulnerability to single- or multiple-year weather disasters.
To focus our efforts in answering this bold question, we concentrate on four issues: (1) Can poverty be erased in the next 20 years? (2) How will school enrollment lead to higher skills in the labor force by 2020? (3) What role will water play in development, in particular, water provision by rain to rural areas, and infrastructure to cities? (4) And, most importantly, what will be the impacts of the HIV/AIDS pandemic in the next decades
Scientific Expertise in Child Protection Policies and Juvenile Justice Practices in Twentieth-Century Belgium
Modern society cannot function without experts and yet we increasingly question the authority of those who advise us. The essays in this collection explore our reliance on experts within a historical context and across a wide range of fields, including agriculture, engineering, health sciences and labour management. Contributors argue that experts were highly aware of their audiences and used performance to gain both scientific and popular support
Fundamental parameters of RR Lyrae stars from multicolour photometry and Kurucz atmospheric models -- II. Adaptation to double-mode stars
Our photometric-hydrodynamic method is generalized to determine fundamental
parameters of multiperiodic radially pulsating stars. We report 302 UBV(RI)_C
Johnson-Kron-Cousins observations of GSC 4868-0831. Using these and published
photometric data of V372 Ser, their metallicity, reddening, distance, mass,
radius, equilibrium luminosity, effective temperature are determined. The
results underline the necessity of using multicolour photometry including an
ultraviolet band to classify properly subgroups of RR Lyrae stars: our U
observations could reveal that GSC 4868-0831 is a subgiant star pulsating in
two radial modes, V372 Ser is a giant star with size and mass of an RRd star.Comment: 10 pages, 4 figures, 5 tables. Accepted for publication in Monthly
Notices RA
Five colour photometry of the RRd star V372 Ser
The first UBV(RI)_C time series photometry of the RRd star V372 Ser is
presented to determine some parameters of the star. In April, May 2007 2812 U,
B, V, R_C, I_C frames were obtained at Konkoly and Teide Observatories, 1508 V
observations were collected from the literature. Fourier fitted light curves
have been derived in all bands. The non-linearly coupled frequencies
f_0=(2.121840+/-.000001) c/day, f_1=(2.851188+/-.000001) c/d, i.e. periods
P_0=0.4712891+/-.0000002 days, P_1=0.3507310+/-.0000001 d, P_1/P_0=0.7441950,
amplitudes A_0(V)=0.15399 mag, A_1(V)=0.20591 mag, and phases have been found.
A_1/A_0=1.319+/-.008 has been found from averaging the amplitude ratio in the
different bands i.e. the first overtone is the dominant pulsation mode. From
the V observations upper limits are given for secular change of the Fourier
parameters. The period ratio and period put V372 Ser among the RRd stars of the
globular clusters M3 and IC 4499, mass, luminosity, and metallicity estimates
are given.Comment: accepted by Astronomy and Astrophysics (5 pages, 3 figures, 4 tables
The Unique Frequency Spectrum of the Blazhko RRc Star LS Her
The Blazhko effect in RR Lyrae stars is still poorly understood
theoretically. Stars with multiple Blazhko periods or in which the Blazhko
effect itself varies are particularly challenging. This study investigates the
Blazhko effect in the RRc star LS Her. Detailed VRI CCD photometry has been
performed on 63 nights during six months. LS Her is confirmed to have a Blazhko
period of 12.75+/-0.02 days. However, where normally the side frequencies of
the Blazhko triplet are expected, an equidistant group of three frequencies is
found on both sides of the main pulsation frequency. As a consequence the
period and amplitude of the Blazhko effect itself vary in a cycle of 109+/-4
days. LS Her is a unique object turning out to be very important in the
verification of the theories for the Blazhko effect.Comment: Accepted for publication in MNRA
Cataclysmic Variables from the Catalina Real-time Transient Survey
We present 855 cataclysmic variable candidates detected by the Catalina
Real-time Transient Survey (CRTS) of which at least 137 have been
spectroscopically confirmed and 705 are new discoveries. The sources were
identified from the analysis of five years of data, and come from an area
covering three quarters of the sky. We study the amplitude distribution of the
dwarf novae CVs discovered by CRTS during outburst, and find that in quiescence
they are typically two magnitudes fainter compared to the spectroscopic CV
sample identified by SDSS. However, almost all CRTS CVs in the SDSS footprint
have ugriz photometry. We analyse the spatial distribution of the CVs and find
evidence that many of the systems lie at scale heights beyond those expected
for a Galactic thin disc population. We compare the outburst rates of newly
discovered CRTS CVs with the previously known CV population, and find no
evidence for a difference between them. However, we find that significant
evidence for a systematic difference in orbital period distribution. We discuss
the CVs found below the orbital period minimum and argue that many more are yet
to be identified among the full CRTS CV sample. We cross-match the CVs with
archival X-ray catalogs and find that most of the systems are dwarf novae
rather than magnetic CVs.Comment: 15 pages, 17 figures, accepted MNRA
General non-rotating perfect-fluid solution with an abelian spacelike C_3 including only one isometry
The general solution for non-rotating perfect-fluid spacetimes admitting one
Killing vector and two conformal (non-isometric) Killing vectors spanning an
abelian three-dimensional conformal algebra (C_3) acting on spacelike
hypersurfaces is presented. It is of Petrov type D; some properties of the
family such as matter contents are given. This family turns out to be an
extension of a solution recently given in \cite{SeS} using completely different
methods. The family contains Friedman-Lema\^{\i}tre-Robertson-Walker particular
cases and could be useful as a test for the different FLRW perturbation
schemes. There are two very interesting limiting cases, one with a non-abelian
G_2 and another with an abelian G_2 acting non-orthogonally transitively on
spacelike surfaces and with the fluid velocity non-orthogonal to the group
orbits. No examples are known to the authors in these classes.Comment: Submitted to GRG, Latex fil
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