4,683 research outputs found
A database for the industrial trawl fishery of Cote d'Ivoire
Fishery statistics for the industrial trawl fishery of Cote d'Ivoire have been well documented since 1968. However, data processing has changed significantly with time and some of the data files have been lost. In 1997, the Centre de Recherches Oceanologiques d'Abidjan decided to retrieve and process all trawl data available from different sources. This paper gives an overview of the database covering the period 1968 to 1997 and describes its coverage, format, structure and use. The database was developed using MS ACCESS and is a powerful tool for storing information about this fishery, and for analysis of its dynamics over a period of 30 years
The Foggy Disks Surrounding Herbig Ae Stars: a Theoretical Study of the H2O Line Spectra
Water is a key species in many astrophysical environments, but it is
particularly important in proto-planetary disks. So far,observations of water
in these objects have been scarce, but the situation should soon change thanks
to the Herschel satellite. We report here a theoretical study of the water line
spectrum of a proto-planetary disk surrounding Ae stars. We show that several
lines will be observable with the HIFI instrument onboard the Herschel Space
Observatory. We predict that some maser lines could also be observable with
ground telescopes and we discuss how the predictions depend not only on the
adopted physical and chemical model but also on the set of collisional
coefficients used and on the H2 ortho to para ratio through its effect on
collisional excitation. This makes the water lines observations a powerful, but
dangerous -if misused- diagnostic tool.Comment: Accepted for publication in ApJ Letter
A deep, wide-field search for substellar members in NGC 2264
We report the first results of our ongoing campaign to discover the first
brown dwarfs (BD) in NGC 2264, a young (3 Myr), populous star forming region
for which our optical studies have revealed a very high density of potential
candidates - 236 in 1 deg - from the substellar limit down to at least
20 M for zero reddening. Candidate BD were first selected
using wide field () band imaging with CFH12K, by reference to current
theoretical isochrones. Subsequently, 79 (33%) of the sample were found
to have near-infrared 2MASS photometry ( 0.3 mag. or better),
yielding dereddened magnitudes and allowing further investigation by comparison
with the location of NextGen and DUSTY isochrones in colour-colour and
colour-magnitude diagrams involving various combinations of ,, and
. We discuss the status and potential substellarity of a number of
relatively unreddened (A 5) likely low-mass members in our
sample, but in spite of the depth of our observations in , we are as yet
unable to unambiguously identify substellar candidates using only 2MASS data.
Nevertheless, there are excellent arguments for considering two faint (observed
18.4 and 21.2) objects as cluster candidates with masses
respectively at or rather below the hydrogen burning limit. More current
candidates could be proven to be cluster members with masses around 0.1
M {\it via} gravity-sensitive spectroscopy, and deeper near-infrared
imaging will surely reveal a hitherto unknown population of young brown dwarfs
in this region, accessible to the next generation of deep near-infrared
surveys.Comment: 10 pages, 12 figures, accepted by A&
Experience of Women with a Diagnosis of Obstructive Sleep Apnea (OSA): A Dissertation
This qualitative descriptive (QD) study examined the experience of the woman newly diagnosed with obstructive sleep apnea (OSA). The study employed Leventhal’s Self- Regulatory Theory to understand women’s illness representation of OSA, cognitive and emotional coping, and situational appraisal skills in coming to terms with OSA. The specific aims were to: 1) Describe the illness representation of women with a recent diagnosis (within one year) of OSA; 2) Describe the cognitive perceptions and emotional response to diagnosis and treatment of OSA in this sample of women; and, 3) Describe the meaning of OSA and the coping strategies used by this sample of women.
The overarching theme of this study of a life-altering diagnosis required participants to process the health threatening information in both a conceptual and concrete process for dealing with both the physical and emotional aspects. The first two subthemes that emerged were Making sense of it, and Making it work as the women came to terms with their symptoms, diagnosis, and adapted to their treatment. For this sample of women, both acceptance (acknowledging the diagnosis of OSA and embracing treatment), and denial (not convinced of diagnosis or need for treatment, seeking alternatives) were factors in how they made sense of the situation. The making it work subtheme dealt with the women’s experiences adapting to treatment both physically and emotionally, including the appraisal, reconsideration and adjustments when they encountered difficulties and delays. A fluid iterative process included women participants describing how they appraised their situation often moving back and forth between acceptance, denial, seeking alternatives, struggling with treatment and moving forward. In both of these subthemes, family support and the stigma of OSA and CPAP were involved in how the women accepted and adapted to treatment. The third subtheme that emerged was Paying it forward as many women felt the obligation to help themselves by adapting a healthier lifestyle for themselves, their families and to assist others impacted by OSA. Women spoke of paying it forward by offering information and support to others not yet diagnosed, or are struggling with diagnosis and treatment. Many of these women were staunch advocates for other women to be tested, for HCPs to be more aware, to be more attuned to women’s sleep history, and to refer women for treatment. Implications of these findings include enhancing recognition and awareness by women of OSA symptoms, the need for diagnostic evaluation, and partner awareness as an important component of diagnosis and successful treatment for women.
Study findings support recognition of women’s presentation of OSA including unusual symptoms for earlier diagnosis and treatment. Sleep partner awareness and support appear to be relevant to women in acceptance of a life altering diagnosis. Further exploration of modifiable factors such as prompt diagnosis and individualized treatment of women with OSA could also impact potential co-morbidities. Provision of further education and awareness by HCPs and insurance companies that women may not present with classic symptoms of OSA is also needed. Targeted interventions specific to women’s experiences with OSA include development of screening tools, care guidelines and treatments that enhance applicability, acceptability, and patient satisfaction. Future advocacy work will also require supporting women in “paying it forward” to help other women diagnosed with OSA
On the stratified dust distribution of the GG Tau circumbinary ring
Our objective is to study the vertical dust distribution in the circumbinary
ring of the binary system GG Tau and to search for evidence of stratification,
one of the first steps expected to occur during planet formation.
We present a simultaneous analysis of four scattered light images spanning a
range of wavelength from 800 nm to 3800 nm and compare them with (i) a
parametric prescription for the vertical dust stratification, and (ii) with the
results of SPH bi-fluid hydrodynamic calculations.
The parametric prescription and hydrodynamical calculations of stratification
both reproduce the observed brightness profiles well. These models also provide
a correct match for the observed star/ring integrated flux ratio. Another
solution with a well-mixed, but ``exotic'', dust size distribution also matches
the brightness profile ratios but fails to match the star/ring flux ratio.
These results give support to the presence of vertical stratification of the
dust in the ring of GG Tau and further predict the presence of a radial
stratification also.Comment: 9 pages, 11 figures. Accepted for publication in A&
Where is the warm H2 ? A search for H2 emission from disks around Herbig Ae/Be stars
Mid-IR emission lines of H2 are useful probes to determine the mass of warm
gas present in the surface layers of disks. Numerous observations of Herbig
Ae/Be stars (HAeBes) have been performed, but only 2 detections of mid-IR H2
toward HD97048 and AB Aur have been reported. We aim at tracing the warm gas in
the disks of 5 HAeBes with gas-rich environments and physical characteristics
close to those of AB Aur and HD97048, to discuss whether the detections toward
these 2 objects are suggestive of peculiar conditions for the gas. We search
for the H2 S(1) emission line at 17.035 \mu\m with VISIR, and complemented by
CH molecule observations with UVES. We gather the H2 measurements from the
literature to put the new results in context and search for a correlation with
some disk properties. None of the 5 VISIR targets shows evidence for H2
emission. From the 3sigma upper limits on the integrated line fluxes we
constrain the amount of optically thin warm gas to be less than 1.4 M_Jup in
the disk surface layers. There are now 20 HAeBes observed with VISIR and TEXES
instruments to search for warm H2, but only two detections (HD97048 and AB Aur)
were made so far. We find that the two stars with detected warm H2 show at the
same time high 30/13 \mu\m flux ratios and large PAH line fluxes at 8.6 and
11.3 \mu\m compared to the bulk of observed HAeBes and have emission CO lines
detected at 4.7 \mu\m. We detect the CH 4300.3A absorption line toward both
HD97048 and AB Aur with UVES. The CH to H2 abundance ratios that this would
imply if it were to arise from the same component as well as the radial
velocity of the CH lines both suggest that CH arises from a surrounding
envelope, while the detected H2 would reside in the disk. The two detections of
the S(1) line in the disks of HD97048 and AB Aur suggest either peculiar
physical conditions or a particular stage of evolution.Comment: accepted for publication in A&A : 10 pages, 6 figure
Burden tests can be used to map causal genes for a simple metabolic trait in an exome-sequenced polyploid mutant population
Forward genetic screens are an excellent tool to assign gene function, but it is often necessary to employ map-based cloning to identify the causal genes. This can be laborious and represents a bottleneck in plant fundamental and applied research. With advances in DNA technology, it is becoming increasingly affordable to sequence large populations. Krasileva et al. (2017) exome sequenced tetraploid and hexaploid wheat ethyl methanesulfonate (EMS) mutagenized populations, primarily to facilitate reverse genetic screens. Gene redundancy allows a very high mutant load of 35–40 mutations per kilobase, and the populations of ~1500 and ~1200 lines each harbour ~22–23 missense or truncation mutations per gene. Here, we show that burden tests, a simple form of rare-variant association analysis developed for human disease genetics (Lee et al., 2014), can be used to identify causal genes in the hexaploid wheat (Triticum aestivum) cv. Cadenza mutant population, without the need for map-based cloning
Proximity effect between two superconductors spatially resolved by scanning tunneling spectroscopy
We present a combined experimental and theoretical study of the proximity
effect in an atomic-scale controlled junction between two different
superconductors. Elaborated on a Si(111) surface, the junction comprises a Pb
nanocrystal with an energy gap of 1.2 meV, connected to a crystalline atomic
monolayer of lead with a gap of 0.23 meV. Using in situ scanning tunneling
spectroscopy we probe the local density of states of this hybrid system both in
space and in energy, at temperatures below and above the critical temperature
of the superconducting monolayer. Direct and inverse proximity effects are
revealed with high resolution. Our observations are precisely explained with
the help of a self-consistent solution of the Usadel equations. In particular,
our results demonstrate that in the vicinity of the Pb islands, the Pb
monolayer locally develops a finite proximity-induced superconducting order
parameter, well above its own bulk critical temperature. This leads to a giant
proximity effect where the superconducting correlations penetrate inside the
monolayer a distance much larger than in a non-superconducting metal.Comment: 13 pages, 14 figures, accepted for publication in Physical Review
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