270 research outputs found
Ranking the Risks: The 10 Pathogen-Food Combinations With the Greatest Burden on Public Health
Examines food-borne pathogens with the highest disease burdens and the top ten foods most commonly contaminated by them, such as salmonella in poultry, toxoplasma in pork, and listeria in deli meats. Makes policy recommendations for improving prevention
The Inner Galaxy resolved at IJK using DENIS data
We present the analysis of three colour optical/near-infrared images, in IJK,
taken for the DENIS project. The region considered covers 17.4 square deg and
lies within |l|<5 deg, |b|<1.5 deg. The adopted methods for deriving photometry
and astrometry in these crowded images, together with an analysis of the
deficiencies nevertheless remaining, are presented. The numbers of objects
extracted in I,J and K are 748000, 851000 and 659000 respectively, to magnitude
limits of 17,15 and 13. 80% completeness levels typically fall at magnitudes
16, 13 and 10 respectively, fainter by about 2 magnitudes than the usual DENIS
limits due to the crowded nature of these fields. A simple model to describe
the disk contribution to the number counts is constructed, and parameters for
the dust layer derived. We find that a formal fit of parameters for the dust
plane, from these data in limited directions, gives a scalelength and
scaleheight of 3.4+-1.0 kpc and 40+-5 pc respectively, and a solar position
14.0+-2.5 pc below the plane. This latter value is likely to be affected by
localised dust asymmetries. We convolve a detailed model of the systematic and
random errors in the photometry with a simple model of the Galactic disk and
dust distribution, to simulate expected colour-magnitude diagrams. These are in
good agreement with the observed diagrams, allowing us to isolate those stars
from the inner disk and bulge. After correcting for local dust-induced
asymmetries, we find evidence for longitude-dependent asymmetries in the
distant J and K sources, consistent with the general predictions of some
Galactic bar models. We consider complementary L-band observations in a second
paper.Comment: 14 pages, 33 figures, LaTeX, MNRAS accepte
First HARPSpol discoveries of magnetic fields in massive stars
In the framework of the Magnetism in Massive Stars (MiMeS) project, a
HARPSpol Large Program at the 3.6m-ESO telescope has recently started to
collect high-resolution spectropolarimetric data of a large number of Southern
massive OB stars in the field of the Galaxy and in many young clusters and
associations. In this Letter, we report on the first discoveries of magnetic
fields in two massive stars with HARPSpol - HD 130807 and HD 122451, and
confirm the presence of a magnetic field at the surface of HD 105382 that was
previously observed with a low spectral resolution device. The longitudinal
magnetic field measurements are strongly varying for HD 130807 from -100
G to 700 G. Those of HD 122451 and HD 105382 are less variable with
values ranging from -40 to -80 G, and from -300 to -600 G,
respectively. The discovery and confirmation of three new magnetic massive
stars, including at least two He-weak stars, is an important contribution to
one of the MiMeS objectives: the understanding of origin of magnetic fields in
massive stars and their impacts on stellar structure and evolution.Comment: 4 pages, 2 figures, accepted for publication in A&A Lette
Harnessing Knowledge to Ensure Food Safety: Opportunities to Improve the Nation\u27s Food Safety Information Infrastructure
Those working in the food industry face an abundance of information generated by diverse institutions and individuals.
Ensuring the safety of food is critically important to the public\u27s health and a challenge for policy-makers seeking to enhance the government\u27s role in this arena. Although the food industry has an inherent duty to make food safe, the effectiveness of what they do is highly dependent on the quality of the information they receive on potential hazards and good practices.
In this context, the Robert Wood Johnson Foundation funded a project under the auspices of the Food Safety Research Consortium to examine and make recommendations for improving the food safety information infrastructure (FSII). Through this initiative, a collection of food safety experts met for a series of workshops to discuss information needs around food safety.
Key Findings: Establish a national FSII policy and program. Build a database for tracking research and data collection. Provide broader public access to journal articles and to complete data from research projects. Create a networking Web site.
In this report, whose recommendations are based on those workshop discussions, the authors explore the constraints facing today\u27s FSII. These include the diversity of the information currently available, the plethora of information sources, and the numerous agencies and actors involved in generating data
ISOGAL: A deep survey of the obscured inner Milky Way with ISO at 7 and 15 micron and with DENIS in the near-infrared
The ISOGAL project is an infrared survey of specific regions sampling the
Galactic Plane selected to provide information on Galactic structure,stellar
populations,stellar mass-loss and the recent star formation history of the
inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 micron ISOCAM
observations - with a resolution of 6'' at worst - with DENIS IJKs data to
determine the nature of the sources and theinterstellar extinction. We have
observed about 16 square degrees with a sensitivity approaching 10-20mJy,
detecting ~10^5 sources,mostly AGB stars,red giants and young stars. The main
features of the ISOGAL survey and the observations are summarized in this
paper,together with a brief discussion of data processing and quality. The
primary ISOGAL products are described briefly (a full description is given in
Schuller et al. 2003, astro-ph/0304309): viz. the images and theISOGAL-DENIS
five-wavelength point source catalogue. The main scientific results already
derived or in progress are summarized. These include astrometrically calibrated
7 and 15um images,determining structures of resolved sources; identification
and properties of interstellar dark clouds; quantification of the infrared
extinction law and source dereddening; analysis of red giant and (especially)
AGB stellar populations in the central Bulge,determining luminosity,presence of
circumstellar dust and mass--loss rate,and source classification,supplemented
in some cases by ISO/CVF spectroscopy; detection of young stellar objects of
diverse types,especially in the inner Bulge with information about the present
and recent star formation rate; identification of foreground sources with
mid-IR excess. These results are the subject of about 25 refereed papers
published or in preparation.Comment: A&A in press. 19 pages,10 Ps figures; problems with figures fixe
Multisite spectroscopic seismic study of the beta Cep star V2052 Oph: inhibition of mixing by its magnetic field
We used extensive ground-based multisite and archival spectroscopy to derive
observational constraints for a seismic modelling of the magnetic beta Cep star
V2052 Ophiuchi. The line-profile variability is dominated by a radial mode
(f_1=7.14846 d^{-1}) and by rotational modulation (P_rot=3.638833 d). Two
non-radial low-amplitude modes (f_2=7.75603 d^{-1} and f_3=6.82308 d^{-1}) are
also detected. The four periodicities that we found are the same as the ones
discovered from a companion multisite photometric campaign (Handler et al.
2012) and known in the literature. Using the photometric constraints on the
degrees l of the pulsation modes, we show that both f_2 and f_3 are prograde
modes with (l,m)=(4,2) or (4,3). These results allowed us to deduce ranges for
the mass (M \in [8.2,9.6] M_o) and central hydrogen abundance (X_c \in
[0.25,0.32]) of V2052 Oph, to identify the radial orders n_1=1, n_2=-3 and
n_3=-2, and to derive an equatorial rotation velocity v_eq \in [71,75] km
s^{-1}. The model parameters are in full agreement with the effective
temperature and surface gravity deduced from spectroscopy. Only models with no
or mild core overshooting (alpha_ov \in [0,0.15] local pressure scale heights)
can account for the observed properties. Such a low overshooting is opposite to
our previous modelling results for the non-magnetic beta Cep star theta Oph
having very similar parameters, except for a slower surface rotation rate. We
discuss whether this result can be explained by the presence of a magnetic
field in V2052 Oph that inhibits mixing in its interior.Comment: 12 pages, 6 figures and 5 tables; accepted for publication in MNRAS
on 2012 August 1
Developmental and Molecular Changes Underlying the Vernalization-Induced Transition to Flowering in Aquilegia coerulea (James)
Reproductive success in plants is dependent on many factors but the precise timing of flowering is certainly among the most crucial. Perennial plants often have a vernalization or over-wintering requirement in order to successfully flower in the spring. The shoot apical meristem undergoes drastic developmental and molecular changes as it transitions into inflorescence meristem (IM) identity, which then gives rise to floral meristems (FMs). In this study, we have examined the developmental and gene expression changes underlying the transition from the vegetative to reproductive phases in the basal eudicot Aquilegia coerulea, which has evolved a vernalization response independently relative to other established model systems. Results from both our histology and scanning electron studies demonstrate that developmental changes in the meristem occur gradually during the third and fourth weeks of vernalization. Based on RNAseq data and cluster analysis, several known flowering time loci, including AqFT and AqFL1, exhibit dramatic changes in expression during the fourth week. Further consideration of candidate gene homologs as well as unexpected loci of interest creates a framework in which we can begin to explore the genetic basis of the flowering time transition in Aquilegia
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