641 research outputs found
Relativistic Mean Field Calculations of and Hypernuclei
Single--particle spectra of and hypernuclei are
calculated within a relativistic mean--field theory. The hyperon couplings used
are compatible with the binding in saturated nuclear matter,
neutron-star masses and experimental data on levels in hypernuclei.
Special attention is devoted to the spin-orbit potential for the hyperons and
the influence of the -meson field (isospin dependent interaction).Comment: 18 pages, including 2 figs., figs. 1 and 4-6 available as
postscript-datasets on request; written in Latex, report# LBL-3303
The power of low-resolution spectroscopy: On the spectral classification of planet candidates in the ground-based CoRoT follow-up
Planetary transits detected by the CoRoT mission can be mimicked by a
low-mass star in orbit around a giant star. Spectral classification helps to
identify the giant stars and also early-type stars which are often excluded
from further follow-up.
We study the potential and the limitations of low-resolution spectroscopy to
improve the photometric spectral types of CoRoT candidates. In particular, we
want to study the influence of the signal-to-noise ratio (SNR) of the target
spectrum in a quantitative way. We built an own template library and
investigate whether a template library from the literature is able to reproduce
the classifications. Including previous photometric estimates, we show how the
additional spectroscopic information improves the constraints on spectral type.
Low-resolution spectroscopy (1000) of 42 CoRoT targets covering a
wide range in SNR (1-437) and of 149 templates was obtained in 2012-2013 with
the Nasmyth spectrograph at the Tautenburg 2m telescope. Spectral types have
been derived automatically by comparing with the observed template spectra. The
classification has been repeated with the external CFLIB library.
The spectral class obtained with the external library agrees within a few
sub-classes when the target spectrum has a SNR of about 100 at least. While the
photometric spectral type can deviate by an entire spectral class, the
photometric luminosity classification is as close as a spectroscopic
classification with the external library. A low SNR of the target spectrum
limits the attainable accuracy of classification more strongly than the use of
external templates or photometry. Furthermore we found that low-resolution
reconnaissance spectroscopy ensures that good planet candidates are kept that
would otherwise be discarded based on photometric spectral type alone.Comment: accepted for publication in Astronomische Nachrichten; 12 pages, 4
figures, 7 table
Should you restrict your cardiac patient from driving?
That depends, of course, on your patient's particular condition, but your decision can be guided by various cardiovascular society consensus conferences, such as the one from the Canadian Cardiovascular Society, since no evidence-based guidelines exist. It seems sensible to say, though, that impairment of consciousness associated with any heart disease needs further evaluation, with a complete restriction of driving for at least 6 months (strength of recommendation [SOR]: C, based on expert opinion and extrapolation from observational studies)
Nuclear surface properties in relativistic effective field theory
We perform Hartree calculations of symmetric and asymmetric semi-infinite
nuclear matter in the framework of relativistic models based on effective
hadronic field theories as recently proposed in the literature. In addition to
the conventional cubic and quartic scalar self-interactions, the extended
models incorporate a quartic vector self-interaction, scalar-vector
non-linearities and tensor couplings of the vector mesons. We investigate the
implications of these terms on nuclear surface properties such as the surface
energy coefficient, surface thickness, surface stiffness coefficient, neutron
skin thickness and the spin-orbit force.Comment: 30 pages, 15 figures. Submitted to Nuclear Physics
The Hercules-Lyra Association revisited New age estimation and multiplicity study
The Her-Lyr assoc., a nearby young MG, contains a few tens of ZAMS stars of
SpT F to M. The existence and the properties of the Her-Lyr assoc. are
controversial and discussed in the literature. The present work reassesses
properties and the member list of Her-Lyr assoc., based on kinematics and age.
Many objects form multiple systems or have low-mass companions and so we need
to account for multiplicity. We use our own new imaging obs. and archival data
to identify multiple systems. The colors and magnitudes of kinematic candidates
are compared to isochrones. We derive further information on the age based on
Li depletion, rotation, and coronal and chromospheric activity. A set of
canonical members is identified to infer mean properties. Membership criteria
are derived from the mean properties and used to discard non-members. The
candidates selected from the literature belong to 35 stellar systems, 42.9% of
which are multiple. Four multiple systems are confirmed in this work by common
proper motion. An orbital solution is presented for the binary system HH Leo B
and C. Indeed, a group of candidates displays signatures of youth. 7 canonical
members are identified. The distribution of EWLi of canonical Her-Lyr members
is spread widely and is similar to that of the Pleiades and the UMa group.
Gyrochronology gives an age of 257+-46 Myr which is in between the ages of the
Pleiades and the Ursa Major group. The measures of chromospheric and coronal
activity support the young age. Four membership criteria are presented based on
kinematics, EWLi, chromospheric activity, and gyro. age. In total, 11 stars are
identified as certain members including co-moving objects plus additional 23
possible members while 14 candidates are doubtful or can be rejected. A
comparison to the mass function, however, indicates the presence of a large
number of additional unidentified low-mass members.Comment: 19 pages 16 figure
What is the appropriate evaluation and treatment of children who are "toe walkers"?
The evaluation of toe-walking focuses on differentiating normal children from those with mild cerebral palsy. Gait analysis may be a useful diagnostic tool, but further investigation is needed to confirm its reliability (strength of recommendation [SOR]: C, based on case series). Observation alone is generally as successful as serial casting and surgery in decreasing the frequency of toe-walking at follow-up (SOR: C, based on case series)
When should you treat scabies empirically?
Empirically treat patients when they have pruritus and lesions typical of scabies in at least 2 places--even if there is no known household contact diagnosed with scabies, and even if the diagnosis cannot be confirmed by light microscopy (strength of recommendation [SOR]: B, based on a single large cohort study). Also give empiric treatment to all sexual and household contacts of anyone diagnosed with scabies (SOR: C, based on expert opinion)
Wandelingen door het kennislandschap : ervaringen met samenwerking tussen Beleidsondersteunend Onderzoek en Groen Onderwijs
Het is de wens van LNV dat onderzoekskennis beter benut wordt in het groene onderwijs. Om hieraan tegemoet te komen hebben een aantal clusterleiders van Wageningen UR het initiatief genomen een Taskforce BO-GO in het leven te roepen. Deze Taskforce heeft in 2007 het project ‘Versterking kenniscirculatie tussen Beleidsondersteunend Onderzoek en Groen Onderwijs – Pilots 2007’ gestart. In het afgelopen jaar zijn in alle clusters van het beleidsondersteunend onderzoek (BO), dat Wageningen UR uitvoert in opdracht van het ministerie van Landbouw Natuur en Voedselkwaliteit (LNV), pilots gestart om de samenwerking met het groene onderwijs (GO) te initiëren en te versterken
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