2,408 research outputs found
New candidate planetary nebulae in M81
A 34 x 34 arcmin field centred on the spiral galaxy M81 has been searched for
emission-line objects using the prime focus wide field camera (WFC) of the 2.54
m Isaac Newton Telescope (La Palma, Spain). A total of 171 candidate planetary
nebulae (PNe) are found, 54 of which are in common with the ones detected by
Jacoby et al. (1989). The behaviour of PNe excitation as a function of
galactocentric distance is examined, and no significant variations are found.
The PNe luminosity function is built for the disk and bulge of M81, separately.
A distance modulus of 27.92+-0.23 mag is found for disk PNe, in good agreement
with previous distance measurements for M81 (Jacoby et al. 1989; Huterer et al.
1995).Comment: 7 pages including 2 tables. A&A accepted; also available at
http://www.iac.es/publicaciones/preprints.htm
Noise Reduction Interventions in the Urban Environment as a form of Control of Indoor Noise Levels
Abstract Traffic noise is a major problem in all large cities and the sound propagation in the urban context is reinforced by the multiple reflections on the building facades. The surface acoustical characteristics (e.g. referred to roads, pedestrian traffic areas, building facades, building surfaces in general) affect the noise propagation in the urban environment. Through a better outdoor design and management (e.g. by means of green areas, porous asphalt, speed control), or building refurbishment actions (acoustic plaster, absorbing shading devices), the increasing of surface absorption could be useful to mitigate noise environmental pollution and therefore to reduce the sound levels in the proximity of the building facades for their entire height. The reduction of the noise levels outside the buildings would determine lower indoor noise levels and therefore a better situation, without direct actions on the building walls. Through a series of noise propagation calculations in urban environments, by means of a three-dimensional simulation model, the influence of some configurations, and the potential impact of some intervention solutions, will be quantified. In the first stage of the research, the analysis of a simplified model is conducted, to evaluate the influence of noise on the buildings facades, based on a simplified geometry of the urban environment and of the surface acoustic features. The same analysis is validated by means of a more detailed model, corresponding to the configuration of an existing built area, to verify if the analyses performed by means of the simplified model can be extended to more complex layouts. Successively, calculations are developed to quantify the noise levels that occur with different acoustic (absorption of facades, soil, asphalt, or green elements) and geometric (road width, buildings height, presence of balconies, etc.) characteristics, to show the potential reduction given by some interventions. Solutions that can lead to a more significant reduction of the noise in correspondence of the facades are then discussed
Spectroscopy of planetary nebulae in M33
Spectroscopic observations of 48 emission-line objects of M33 have been
obtained with the multi-object, wide field, fibre spectrograph AF2/WYFFOS at
the 4.2m WHT telescope (La Palma, Spain). Line intensities and logarithmic
extinction, cbeta, are presented for 42 objects. Their location in the Sabbadin
& D'Odorico diagnostic diagram (Halpha/[SII] vs Hlapha/[NII]) suggests that
>70% of the candidates are Planetary Nebulae (PNe). Chemical abundances and
nebular physical parameters have been derived for the three of the six PNe
where the 4363A [OIII] emission line was measurable. These are disc PNe,
located within a galactocentric distance of 4.1 kpc, and, to date, they are the
farthest PNe with a direct chemical abundance determination. No discrepancy in
the Helium, Oxygen and Argon abundances has been found in comparison with
corresponding abundances of PNe in our Galaxy. Only a lower limit to the
sulphur abundance has been obtained since we could not detect any [SIII] line.
N/H appears to be lower than the Galactic value; some possible explanations for
this under-abundance are discussed.Comment: 18 pages, 1 JPEG figure and 3 Postscript figures, Accepted for
publication in A&
Abundances and kinematics for ten anticentre open clusters
Open clusters are distributed all across the disk and are convenient tracers
of its properties. In particular, outer disk clusters bear a key role for the
investigation of the chemical evolution of the Galactic disk. The goal of this
study is to derive homogeneous elemental abundances for a sample of ten outer
disk OCs, and investigate possible links with disk structures such as the
Galactic Anticenter Stellar Structure. We analyse high-resolution spectra of
red giants, obtained from the HIRES@Keck and UVES@VLT archives. We derive
elemental abundances and stellar atmosphere parameters by means of the
classical equivalent width method. We also performed orbit integrations using
proper motions. The Fe abundances we derive trace a shallow negative radial
metallicity gradient of slope -0.027+/-0.007 dex.kpc-1 in the outer 12 kpc of
the disk. The [alpha/Fe] gradient appears flat, with a slope of 0.006+/-0.007
dex.kpc-1 . The two outermost clusters (Be 29 and Sau 1) appear to follow
elliptical orbits. Be 20 also exhibits a peculiar orbit with a large excursion
above the plane. The irregular orbits of the three most metal-poor clusters (of
which two are located at the edge of the Galactic disk), if confirmed by more
robust astrometric measurements such as those of the Gaia mission, are
compatible with an inside-out formation scenario for the Milky Way, in which
extragalactic material is accreted onto the outer disk. We cannot determine if
Be 20, Be 29,and Sau 1 are of extragalactic origin, as they may be old genuine
Galactic clusters whose orbits were perturbed by accretion events or minor
mergers in the past 5 Gyr, or they may be representants of the thick disk
population. The nature of these objects is intriguing and deserves further
investigations in the near future.Comment: 17 pages, 9 figures; accepted for publication in A&
Plasma adrenomedullin is associated with short-term mortality and vasopressor requirement in patients admitted with sepsis
Introduction: The incidence of death among patients admitted for severe sepsis or septic shock is high. Adrenomedullin (ADM) plays a central role in initiating the hyperdynamic response during the early stages of sepsis. Pilot studies indicate an association of plasma ADM with the severity of the disease. In the present study we utilized a novel sandwich immunoassay of bioactive plasma ADM in patients hospitalized with sepsis in order to assess the clinical utility.Methods: We enrolled 101 consecutive patients admitted to the emergency department with suspected sepsis in this study. Sepsis was defined by fulfillment of at least two systemic inflammatory response syndrome (SIRS) criteria plus clinical suspicion of infection. Plasma samples for ADM measurement were obtained on admission and for the next four days. The 28-day mortality rate was recorded.Results: ADM at admission was associated with severity of disease (correlation with Acute Physiology and Chronic Health Evaluation II (APACHE II) score: r = 0.46; P <0.0001). ADM was also associated with 28-day mortality (ADM median (IQR): survivors: 50 (31 to 77) pg/mL; non-survivors: 84 (48 to 232) pg/mL; P <0.001) and was independent from and additive to APACHE II (P = 0.02). Cox regression analysis revealed an additive value of serial measurement of ADM over baseline assessment for prediction of 28-day mortality (P < 0.01). ADM was negatively correlated with mean arterial pressure (r = -0.39; P <0.0001), and it strongly discriminated those patients requiring vasopressor therapy from the others (ADM median (IQR): no vasopressors 48 (32 to 75) pg/mL; with vasopressors 129 (83 to 264) pg/mL, P <0.0001).Conclusions: In patients admitted with sepsis, severe sepsis or septic shock plasma ADM is strongly associated with severity of disease, vasopressor requirement and 28-day mortality
The S2N2 metallicity calibrator and the abundance gradient of M 33
We introduce the log(Ha/[SII]6717+6731) vs. log(Ha/[NII]6583) (S2N2)
diagnostic diagram as metallicity and ionisation parameter indicator for HII
regions in external galaxies. The location of HII regions in the S2N2 diagram
was studied both empirically and theoretically. We found that, for a wide range
of metallicities, the S2N2 diagram gives single valued results in the
metallicity-ionisation parameter plane. We demonstrate that the S2N2 diagram is
a powerful tool to estimate metallicities of high-redshift (z ~ 2) HII
galaxies. Finally, we derive the metallicity for 76 HII regions in M33 from the
S2N2 diagram and calculate an O/H abundance gradient for this galaxy of -0.05
(+-0.01) dex kpc^-1.Comment: 10 pages, 3 figures and 2 tables. Accepted for publication in MNRA
The Local Group Census: planetary nebulae in Sextans B
Five planetary nebulae (PNe) have been discovered in the nearby dwarf
irregular galaxy. Emission line images were obtained using the Wide Field
Camera of the 2.5m Isaac Newton Telescope (INT) at La Palma (Spain). The
candidate PNe were identified by their point-like appearance and relatively
strong [OIII] emission-line fluxes. They are located within a galactocentric
distance of 2.8 arcmin, corresponding to 1.1 kpc at the distance of Sextans B.
Luminosities are in the range 1800--5600Lsolar. Sextans B is one of the
smallest dwarf irregular galaxies with a PN population. The number of PNe
detected suggest an enhanced star formation rate between 1 and 5 Gyr ago.Comment: 7 pages, 2 figure
Measuring antibiotic availability and use in 20 low- and middle-income countries
Objective To assess antibiotic availability and use in health facilities in low- and middle-income countries, using the service provision assessment and service availability and readiness assessment surveys.
Methods We obtained data on antibiotic availability at 13 561 health facilities in 13 service provision assessment and 8 service availability and readiness assessment surveys. In 10 service provision assessment surveys, child consultations with health-care providers were observed, giving data on antibiotic use in 22 699 children. Antibiotics were classified as access, watch or reserve, according to the World Health Organization’s AWaRe categories. The percentage of health-care facilities across countries with specific antibiotics available and the proportion of children receiving antibiotics for key clinical syndromes were estimated.
Findings The surveys assessed the availability of 27 antibiotics (19 access, 7 watch, 1 unclassified). Co-trimoxazole and metronidazole were most widely available, being in stock at 89.5% (interquartile range, IQR: 11.6%) and 87.1% (IQR: 15.9%) of health facilities, respectively. In contrast, 17 other access and watch antibiotics were stocked, by fewer than a median of 50% of facilities. Of the 22 699 children observed, 60.1% (13 638) were prescribed antibiotics (mostly co-trimoxazole or amoxicillin). Children with respiratory conditions were most often prescribed antibiotics (76.1%; 8972/11 796) followed by undifferentiated fever (50.1%; 760/1518), diarrhoea (45.7%; 1293/2832) and malaria (30.3%; 352/1160).
Conclusion Routine health facility surveys provided a valuable data source on the availability and use of antibiotics in low- and middle-income countries. Many access antibiotics were unavailable in a majority of most health-care facilities
A gas-rich AGN near the centre of a galaxy cluster at z ~ 1.4
The formation of the first virialized structures in overdensities dates back
to ~9 Gyr ago, i.e. in the redshift range z ~ 1.4 - 1.6. Some models of
structure formation predict that the star formation activity in clusters was
high at that epoch, implying large reservoirs of cold molecular gas. Aiming at
finding a trace of this expected high molecular gas content in primeval
clusters, we searched for the 12CO(2-1) line emission in the most luminous
active galactic nucleus (AGN) of the cluster around the radio galaxy 7C
1756+6520 at z ~ 1.4, one of the farthest spectroscopic confirmed clusters.
This AGN, called AGN.1317, is located in the neighbourhood of the central radio
galaxy at a projected distance of ~780 kpc. The IRAM Plateau de Bure
Interferometer was used to investigate the molecular gas quantity in AGN.1317,
observing the 12CO(2-1) emission line. We detect CO emission in an AGN
belonging to a galaxy cluster at z ~ 1.4. We measured a molecular gas mass of
1.1 x 10^10 Msun, comparable to that found in submillimeter galaxies. In
optical images, AGN.1317 does not seem to be part of a galaxy interaction or
merger.We also derived the nearly instantaneous star formation rate (SFR) from
Halpha flux obtaining a SFR ~65 Msun/yr. This suggests that AGN.1317 is
actively forming stars and will exhaust its reservoir of cold gas in ~0.2-1.0
Gyr.Comment: 5 pages, 3 figures, accepted for publication in Astronomy &
Astrophysic
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