3,530 research outputs found
Ghosts of Milky Way's past: the globular cluster ESO 37-1 (E 3)
Context. In the Milky Way, most globular clusters are highly conspicuous
objects that were found centuries ago. However, a few dozen of them are faint,
sparsely populated systems that were identified largely during the second half
of the past century. One of the faintest is ESO 37-1 (E 3) and as such it
remains poorly studied, with no spectroscopic observations published so far,
although it was discovered in 1976.
Aims. We investigate the globular cluster E 3 in an attempt to better
constrain its fundamental parameters. Spectroscopy of stars in the field of E 3
is shown here for the first time.
Methods. Deep, precise VI CCD photometry of E 3 down to V=26 mag is presented
and analysed. Low-resolution, medium signal-to-noise ratio spectra of nine
candidate members are studied to derive radial velocity and metallicity. Proper
motions from the UCAC4 catalogue are used to explore the kinematics of the
bright members of E 3.
Results. Isochrone fitting indicates that E 3 is probably very old, with an
age of about 13 Gyr; its distance from the Sun is nearly 10 kpc. It is also
somewhat metal rich with [Fe/H]=-0.7. Regarding its kinematics, our tentative
estimate for the proper motions is (-7.0+/-0.8, 3.5+/-0.3) mas/yr (or a
tangential velocity of 382+/-79 km/s) and for the radial velocity is 45+/-5
km/s, in the solar rest frame.
Conclusions. E 3 is one of the most intriguing globular clusters in the
Galaxy. Having an old age and being metal rich is clearly a peculiar
combination, only seen in a handful of objects like the far more conspicuous
NGC 104 (47 Tucanae). In addition, its low luminosity and sparse population
make it a unique template for the study of the final evolutionary phases in the
life of a star cluster. Unfortunately, E 3 is among the most elusive and
challenging known globular clusters because field contamination severely
hampers spectroscopic studies.Comment: 7 pages, 6+1 figures, 2 tables. Accepted for publication in Astronomy
and Astrophysics. Minor change
A Rubric for Electrochemical Testing of Metallic Biomaterials
Corrosion is a major factor for the failure of metallic medical implants. Testing a metal’s suseptability to corrosion prior to implantation is key to a successful implantation. Electrochemical processes were used in this study to evaluate the characteristics of corrosion of both AISI 316 stainless steel and titanium alloy Ti6Al4V, welded and non-welded. Linear, potentiodynamic, and cyclic polarization curves were produced by the PARC 2273 potentiostat showing the corrosion tendencies of the metals in four unique solutions 3.5% NaCl, 0.35% NaCl, phosphate buffered saline solution (PBS), and Butterfield phosphate buffered solution (BPS). The concentration of chloride ions in solutions affected the passivation current (Ipassive) and the passivation range of both AISI 316 and Ti6Al4V. In general, larger concentrations of the chloride ions increased the passivation current and decreased the passivation range. Both AISI 316 and Ti6Al4V exhibited passive behavior. Ti6Al4V proved to be the more corrosion resistant metal in the test solutions, showing the ability to repassivate and resist pitting
Personalised medicine, unmet need or business strategy?
Personalised medicine is a discipline that integrates pharmaceutical development with existing knowledge about the genetic and phenotypic factors that influence drug response. This integration enables tailoring therapies to individual patient’s characteristics to help improve their safety and efficacy. Personalised medicine implies a shift in the way drugs are delivered as it requires new forms of testing that assess the patient´s eligibility for a drug. This poses new challenges, both at a regulatory and reimbursement level. Personalised medicine has reached higher commercial success and clinical uptake in drugs under development than old and off-patent drugs. This paper uses the case of TPMT testing to illustrate the reasons why personalised medicine for off-patent drugs is less used at a clinical level than personalised medicine for drugs under development.<br
NGC 5385, NGC 2664 and Collinder 21: three candidate Open Cluster Remnants
We present CCD UBVI photometric and medium/high resolution spectroscopic
observations obtained in the field of the previously unstudied dissolving open
cluster candidates NGC 5385, NGC 2664 and Collinder~21. Our analysis stands on
the discussion of star counts, photometry, radial velocity distribution, and
proper motions available from the Tycho~2 catalogue. All the three aggregates
clearly emerge from the mean Galactic field, but, regrettably, the close
scrutiny of proper motions and radial velocities reveals that we are not facing
any physical group. Instead, what we are looking at are just chance alignments
of a few bright unrelated stars. Our analysis casts some doubt on the Bica et
al. (2001) criterion to look for Possible Open Cluster Remnants. It seems
mandatory to define a better criterion to adopt for further investigations.Comment: 12 pages, 12 eps figures (7, 9 and 11 degraded in resolution),
accepted for publication in Astronomy & Astrophysic
Spotted Fever Group Rickettsiae in Questing Ticks, Central Spain
These results demonstrate that SFG rickettsiae with public health relevance are found in ticks in central Spain as in other regions in Spain. In central Spain, the widespread distribution of tick vectors and possible wildlife hosts, the presence of persons in tick-infested recreational and hunting areas, and the transstadial and transovarial transmission of the pathogen in ticks may favor transmission to humans.Fil: Fernandez de Mera, Isabel G.. Consejo Superior de Investigaciones Cientificas. Instituto de InvestigaciĂłn en Recursos CinegĂ©ticos; España;Fil: Ruiz-Fons, Francisco. Consejo Superior de Investigaciones Cientificas. Instituto de InvestigaciĂłn en Recursos CinegĂ©ticos; España;Fil: de la Fuente, Gabriela. Consejo Superior de Investigaciones Cientificas. Instituto de InvestigaciĂłn en Recursos CinegĂ©ticos; España;Fil: Mangold, Atilio Jose. Instituto Nacional de TecnologĂa Agropecuaria. Centro Regional Santa Fe. EstaciĂłn Experimental Agropecuaria, Rafaela; Argentina; Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina;Fil: Gortázar, Christian. Consejo Superior de Investigaciones Cientificas. Instituto de InvestigaciĂłn en Recursos CinegĂ©ticos; España;Fil: de la Fuente, JosĂ©. Oklahoma State University; Estados Unidos de AmĂ©rica
Spotted fever group rickettsiaein questing ticks, central Spain
Letter to the Editor.F. R.-F. and I.G.F.M. are supported by a Juan de la Cierva contract from
the Spanish Ministry for Economy and Competitiveness. Research supported by
POII09-0141-8176 and European Union FP7 ANTIGONE (Anticipating the Global
Onset of Novel Epidemics) project number 278976.Peer Reviewe
Identification and characterization of Rhipicephalus (Boophilus) microplus candidate protective antigens for the control of cattle tick infestations
The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this antigen. These experiments showed that RNAi could be used for the selection of candidate tick-protective antigens. However, vaccination trials are necessary to evaluate the effect of recombinant antigens in the control of tick infestations, a process that requires efficient recombinant protein production and formulation systems
Not an open cluster after all: the NGC 6863 asterism in Aquila
Shortly after birth, open clusters start dissolving; gradually losing stars
into the surrounding star field. The time scale for complete disintegration
depends both on their initial membership and location within the Galaxy. Open
clusters undergoing the terminal phase of cluster disruption or open cluster
remnants (OCRs) are notoriously difficult to identify. From an observational
point, a combination of low number statistics and minimal contrast against the
general stellar field conspire to turn them into very challenging objects. To
make the situation even worst, random samples of field stars often display
features that may induce to classify them erroneously as extremely evolved open
clusters. In this paper, we provide a detailed study of the stellar content and
kinematics of NGC 6863, a compact group of a few stars located in Aquila and
described by the POSS as a non existent cluster. Nonetheless, this object has
been recently classified as OCR. The aim of the present work is to either
confirm or disprove its OCR status by a detailed star-by-star analysis. The
analysis is performed using wide-field photometry in the UBVI pass-band, proper
motions from the UCAC3 catalogue, and high resolution spectroscopy as well as
results from extensive -body calculations. Our results show that the four
brightest stars commonly associated to NGC 6863 form an asterism, a group of
non-physically associated stars projected together, leading to the conclusion
that NGC 6863 is not a real open cluster.Comment: 10 pages, 8 eps figure, in press in Astronomy and Astrophysis.
Abstract shortened to fit i
Genetic relationships within and among Iberian fescues (Festuca L.) based on PCR-amplified markers
The genus Festuca comprises approximately 450 species and is widely distributed around the world. The Iberian Penninsula, with more than 100 taxa colonizing very diverse habitats, is one of its main centers of diversification. This study was conducted to assess molecular genetic variation and genetic relatedness among 91 populations of 31 taxa of Iberian fescues, based on several molecular markers (random amplified polymorphic DNA, amplified fragment length polymorphisms, and trnL sequences). The analyses showed the paraphyletic origin of the broad-leaved (subgenus Festuca, sections Scariosae and Subbulbosae, and subgenus Schedonorus) and the fine-leaved fescues (subgenus Festuca, sections Aulaxyper, Eskia, and Festuca). Schedonorus showed a weak relationship with Lolium rigidum and appeared to be the most recent of the broad-leaved clade. Section Eskia was the most ancient and Festuca the most recent of the fine-leaved clade. Festuca and Aulaxyper were the most related sections, in concordance with their taxonomic affinities. All taxa grouped into their sections, except F. ampla and F. capillifolia (section Festuca), which appeared to be more closely related to Aulaxyper and to a new independent section, respectively. Most populations clustered at the species level, but some subspecies and varieties mixed their populations. This study demonstrated the value in combining different molecular markers to uncover hidden genetic relationships between populations of Festuca
A new record of the invasive seaweed Caulerpa cylindracea Sonder in the South Adriatic Sea
The green alga Caulerpa cylindracea Sonder is one of the most infamous and threatening invasive species in the Mediterranean Sea. Since 1985, it started rapidly spreading to all Mediterranean regions causing many ecological changes on natural communities. In the present study, we present an example of this proliferation with the first record in the Marine Protected Area of Tremiti Island (MPATI) in the South Adriatic Sea. Fifteen sites along the coast and 5 different depths have been investigated. Our results provide eveidence of a wide invasion of this pest in three islands, San Domino, San Nicola and Capraia. This study fills a particular data gap in the ongoing biomonitoring of invasive seaweeds in the Mediterranean Sea representing a base line of this invasive species for the MPATI
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