689 research outputs found
Spin and energy correlations in the one dimensional spin 1/2 Heisenberg model
In this paper, we study the spin and energy dynamic correlations of the one
dimensional spin 1/2 Heisenberg model, using mostly exact diagonalization
numerical techniques. In particular, observing that the uniform spin and energy
currents decay to finite values at long times, we argue for the absence of spin
and energy diffusion in the easy plane anisotropic Heisenberg model.Comment: 10 pages, 3 figures, gzipped postscrip
No planet for HD 166435
The G0V star HD166435 has been observed by the fiber-fed spectrograph ELODIE
as one of the targets in the large extra-solar planet survey that we are
conducting at the Observatory of Haute-Provence. We detected coherent,
low-amplitude, radial-velocity variations with a period of 3.7987days,
suggesting a possible close-in planetary companion. Subsequently, we initiated
a series of high-precision photometric observations to search for possible
planetary transits and an additional series of CaII H and K observations to
measure the level of surface magnetic activity and to look for possible
rotational modulation. Surprisingly, we found the star to be photometrically
variable and magnetically active. A detailed study of the phase stability of
the radial-velocity signal revealed that the radial-velocity variability
remains coherent only for durations of about 30days. Analysis of the time
variation of the spectroscopic line profiles using line bisectors revealed a
correlation between radial velocity and line-bisector orientation. All of these
observations, along with a one-quarter cycle phase shift between the
photometric and the radial-velocity variationss, are well explained by the
presence of dark photospheric spots on HD166435. We conclude that the
radial-velocity variations are not due to gravitational interaction with an
orbiting planet but, instead, originate from line-profile changes stemming from
star spots on the surface of the star. The quasi-coherence of the
radial-velocity signal over more than two years, which allowed a fair fit with
a binary model, makes the stability of this star unusual among other active
stars. It suggests a stable magnetic field orientation where spots are always
generated at about the same location on the surface of the star.Comment: 9 pages, 8 figures, Accepted for publication in A&
Implementation of a multicomponent family support intervention in adult intensive care units: study protocol for an embedded mixed-methods multiple case study (FICUS implementation study)
- Background: The implementation of complex interventions is considered challenging, particularly in multi-site clinical trials and dynamic clinical settings. This study protocol is part of the family intensive care units (FICUS) hybrid effectiveness-implementation study. It aims to understand the integration of a multicomponent family support intervention in the real-world context of adult intensive care units (ICUs). Specifically, the study will assess implementation processes and outcomes of the study intervention, including fidelity, and will enable explanation of the clinical effectiveness outcomes of the trial.
- Methods and analysis: This mixed-methods multiple case study is guided by two implementation theories, the Normalisation Process Theory and the Consolidated Framework for Implementation Research. Participants are key clinical partners and healthcare professionals of eight ICUs allocated to the intervention group of the FICUS trial in the German-speaking part of Switzerland. Data will be collected at four timepoints over the 18-month active implementation and delivery phase using qualitative (small group interviews, observation, focus group interviews) and quantitative data collection methods (surveys, logs). Descriptive statistics and parametric and non-parametric tests will be used according to data distribution to analyse within and between cluster differences, similarities and factors associated with fidelity and the level of integration over time. Qualitative data will be analysed using a pragmatic rapid analysis approach and content analysis.
- Ethics and dissemination: Ethics approval was obtained from the Cantonal Ethics Committee of Zurich BASEC ID 2021-02300 (8 February 2022). Study findings will provide insights into implementation and its contribution to intervention outcomes, enabling understanding of the usefulness of applied implementation strategies and highlighting main barriers that need to be addressed for scaling the intervention to other healthcare contexts. Findings will be disseminated in peer-reviewed journals and conferences.
- Protocol registration number: Open science framework (OSF)https://osf.io/8t2ud Registered on 21 December 2022
The HARPS search for southern extra-solar planets. XXIV. Companions to HD 85390, HD 90156 and HD 103197: A Neptune analogue and two intermediate mass planets
We report the detection of three new extrasolar planets orbiting the solar
type stars HD 85390, HD 90156 and HD 103197 with the HARPS spectrograph mounted
on the ESO 3.6-m telescope at La Silla observatory. HD 85390 has a planetary
companion with a projected intermediate mass (42.0 Earth masses) on a 788-day
orbit (a=1.52 AU) with an eccentricity of 0.41, for which there is no analogue
in the solar system. A drift in the data indicates the presence of another
companion on a long period orbit, which is however not covered by our
measurements. HD 90156 is orbited by a warm Neptune analogue with a minimum
mass of 17.98 Earth masses (1.05 Neptune masses), a period of 49.8 days (a=0.25
AU) and an eccentricity of 0.31. HD 103197 has an intermediate mass planet on a
circular orbit (P=47.8 d, Msini=31.2 Earth masses). We discuss the formation of
planets of intermediate mass (about 30-100 Earth masses) which should be rare
inside a few AU according to core accretion formation models.Comment: 9 pages, 5 figures. Accepted to A&
The ELODIE survey for northern extra--solar planets I. 6 new extra--solar planet candidates
Precise radial-velocity observations at Haute-Provence Observatory (OHP,
France) with the ELODIE echelle spectrograph have been undertaken since 1994.
In addition to several discoveries described elsewhere, including and following
that of 51 Peg b, they reveal new sub-stellar companions with essentially
moderate to long periods. We report here about such companions orbiting five
solar-type stars (HD 8574, HD 23596, HD 33636, HD 50554, HD 106252) and one
sub-giant star (HD 190228). The companion of HD 8574 has an intermediate period
of 227.55 days and a semi--major axis of 0.77 AU. All other companions have
long periods, exceeding 3 years, and consequently their semi-major axes are
around or above 2 AU. The detected companions have minimum masses m2sini
ranging from slightly more than 2 M_Jup to 10.6 M_Jup. These additional objects
reinforce the conclusion that most planetary companions have masses lower than
5 M_Jup but with a tail of the mass distribution going up above 15 M_Jup. The
orbits are all eccentric and 4 out of 6 have an eccentricity of the order of
0.5. Four stars exhibit solar metallicity, one is metal-rich and one
metal-poor. With 6 new extra-solar planet candidates discovered, increasing
their total known to-date number to 115, the ELODIE Planet Search Survey yield
is currently 18. We emphasize that 3 out of the 6 companions could in principle
be resolved by diffraction-limited imaging on 8m-class telescopes depending on
the achievable contrast, and therefore be primary targets for first attempts of
extra-solar planet direct imaging.Comment: 13 pages, 10 figures, 3 tables, accepted for publication in A&A,
appendix A will only appear in the electronic versio
Control of Daily Transcript Oscillations in Drosophila by Light and the Circadian Clock
The transcriptional circuits of circadian clocks control physiological and behavioral rhythms. Light may affect such overt rhythms in two ways: (1) by entraining the clock circuits and (2) via clock-independent molecular pathways. In this study we examine the relationship between autonomous transcript oscillations and light-driven transcript responses. Transcript profiles of wild-type and arrhythmic mutant Drosophila were recorded both in the presence of an environmental photocycle and in constant darkness. Systematic autonomous oscillations in the 12- to 48-h period range were detectable only in wild-type flies and occurred preferentially at the circadian period length. However, an extensive program of light-driven expression was confirmed in arrhythmic mutant flies. Many light-responsive transcripts are preferentially expressed in the compound eyes and the phospholipase C component of phototransduction, NORPA (no receptor potential), is required for their light-dependent regulation. Although there is evidence for the existence of multiple molecular clock circuits in cyanobacteria, protists, plants, and fungi, Drosophila appears to possess only one such system. The sustained photic expression responses identified here are partially coupled to the circadian clock and may reflect a mechanism for flies to modulate functions such as visual sensitivity and synaptic transmission in response to seasonal changes in photoperiod
"Medikamente sind Bomben" - zum Metapherngebrauch von Lungentransplantations-Patienten mit guter oder ungenügender Compliance
Fragestellung: Nach einer Organtransplantation finden komplexe psychologische Verarbeitungsprozesse statt. In der vorliegenden Studie wurde untersucht, welche Metaphern im Zusammenhang mit Transplantationserfahrungen verwendet werden, und ob Unterschiede zwischen Patienten mit guter bzw. ungenügender Compliance im Gebrauch dieser Metaphern bestehen.
Methode: 14 lungentransplantierte Patienten wurden in einem halbstrukturierten Interview zu ihren Transplantationserfahrungen befragt. Ihre Compliance wurde von den behandelnden Ärzten eingeschätzt. Die Auswertung der Interviews erfolgte anhand einer Metaphernanalyse, welche Hinweise auf vor- und unbewusste Vorstellungen der Patienten liefert. Die Interraterreliabilität über die Metapherngruppen war Cohen’s Kappa K = 0.8.
Ergebnisse: Die Patienten konzeptualisierten ihren Körper, aber auch ihr Selbst als ein “Gefäß”, dass sowohl materielle (z.B. die Lunge) wie immaterielle Objekte (z.B. Gedanken an den Spender, Affekte) enthält. Der wichtigste Unterschied zwischen den Compliance-Gruppen bestand darin, dass Patienten mit ungenügender Compliance eine grössere Distanz zur transplantierten Lunge erlebten. Auch konzeptualisierten sie ihren Körper bzw. ihr Selbst nicht als ein Gefäß, das die Lunge enthält.
Diskussion: Die Ergebnisse zeigen, dass gute Compliance mit einer erfolgreichen Organintegration assoziiert ist, welche die Zugehörigkeit der Lunge in einem als Gefäß konzeptualisierten Körper bzw. Selbst umfasst. Patienten mit ungenügender Compliance nehmen die Lunge eher als Fremdkörper wahr. Diese Verarbeitungsprozesse sind teils bewusster, teils vor- und unbewusster Natur
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