7,327 research outputs found
Galaxy evolution across the optical emission-line diagnostic diagrams?
The discovery of the M-sigma relation, the local galaxy bimodality, and the
link between black-hole and host-galaxy properties, have raised the question
whether AGN play a role in galaxy evolution. Several theoretical models
implement AGN feedback to explain the observed galaxy luminosity function, and
possibly the color and morphological transformation of spiral galaxies into
passive ellipticals. To understand the importance of AGN feedback, a study of
the AGN populations in the radio-optical domain is crucial. A mass sequence
linking star-forming galaxies and AGN has been already noted in previous works,
and it is now investigated as possible evolutionary sequence. We observed a
sample of 119 intermediate-redshift (0.04<z<0.4) SDSS-FIRST radio emitters with
the Effelsberg 100-m telescope at 4.85 and 10.45 GHz and obtained spectral
indices. We find indications of spectral index flattening in high-metallicity
star-forming galaxies, composite galaxies, and Seyferts. This "flattening
sequence" along the [NII]-based emission-line diagnostic diagram is consistent
with the hardening of galaxy ionizing field, due to nuclear activity. After
combining our data with FIRST measurements at 1.4 GHz, we find that the
three-point radio spectra of Seyferts and LINERs show substantial differences,
attributable to small radio core components and larger (arcsecond sized)
jet/lobe components, respectively. A visual inspection of FIRST images seems to
confirm this hypothesis. Galaxies along this sequence are hypothesized to be
transitioning from the active star-forming galaxies (blue cloud) to the passive
elliptical galaxies (red sequence). This supports the suggestion that AGN play
a role in shutting down star-formation, and allow the transition from one
galaxy class to the other.Comment: 20 pages, 19 figures, accepted for publication in A&
Ecological design of a crayfishing program to control population density of the invasive species Procambarus Clarkii in Doñana National Park freshwater marsh (Spain)
The exploitation of Procambarus clarkii in Doñana National Park’s freshwater marsh (DNP) has been economically important to the local human population since the 1970s. The high density of this crayfish species has been causing a major environmental impact in the Park by the substantial reduction of submerging aquatic macrophytes prairies due to its broad trophic spectrum and feeding habits, which turned the environmental frame (consisting in clear water equilibrium) into a turbid water balance. Differences in population dynamics of three population groups of P. clarkii in the DNP freshwater marsh were compared and analyzed from a fishery perspective. The objective is to reduce their ecological impact using optimal crayfishing management. Maximum growth curves showed that crayfish have different growth optimums. Recruitment of young crayfish varies between different populations; when there is an excessive increase in the density of juveniles in a population and conditions are stressful, their growth is deficient. If these conditions persist, the population could become stunted. Fishery for commercial gain is banned in DNP; however, a model of fisheries program aimed at controlling the excess population of crayfish can be effective in halting the ecological impact of this invasive species while providing an opportunity for poachers to have viable productive options. The model proposed can help to solve the problem of crayfish “poaching” through the legalization and strict control of harvesting practicesPedro J. Gutiérrez-Yurrita also thanks the ICI (Spain) for a subvention grant and CONACyT (México) for a financial complement of the former grant that enabled him to complete this researc
Discovery of Blue Hook Stars in the Massive Globular Cluster M54
We present BV photometry centered on the globular cluster M54 (NGC 6715). The
color-magnitude diagram clearly shows a blue horizontal branch extending
anomalously beyond the zero age horizontal branch theoretical models. These
kinds of horizontal branch stars (also called ``blue hook'' stars), which go
beyond the lower limit of the envelope mass of canonical horizontal branch hot
stars, have so far been known to exist in only a few globular clusters: NGC
2808, Omega Centauri (NGC 5139), NGC 6273, and NGC 6388. Those clusters, like
M54, are among the most luminous in our Galaxy, indicating a possible
correlation between the existence of these types of horizontal branch stars and
the total mass of the cluster. A gap in the observed horizontal branch of M54
around T(eff)= 27000 K could be interpreted within the late helium flash
theoretical scenario, a possible explanation for the origin of those stars.Comment: 10 pages, 2 figures, accepted for publication in the Astrophysical
Journa
In vitro effects of resistin on epithelial to mesenchymal transition (EMT) in MCF-7 and MDA-MB-231 breast cancer cells - qRT-PCR and Westen blot analyses data.
Resistin is an adipokine produced by the white adipocytes and adipose-derived macrophages, which mediates inflammation and insulin resistance Huang et al., 1997 and Renehan et al., 2008 Feb. Here, we provide data on the effect of resistin on epithelial to mesenchymal transition (EMT) in breast cancer cells in vitro. As model systems, we used human MCF-7 (low-metastatic) and MDA-MB-231 (high-metastatic) breast cancer cell lines. To optimize experimental conditions, we treated the cells with various concentrations of resistin (12.5, 25 and 50 ng/ml) for different time intervals (6 and 24 hours), and measured SOCS3 mRNA expression by using qRT-PCR analysis. Further, we used qRT-PCR and Western blot analyses to measure the expression of various epithelial (E-cadherin, claudin-1) and mesenchymal (SNAIL, SLUG, ZEB1, TWIST1, fibronectin, and vimentin) markers after resistin treatment. This data article is part of a study Avtanski et al., 2019 May, where detailed interpretation and discussion can be found
Aloinjerto como material de relleno de defecto óseo metafisario en las fracturas de platillo tibial
El propósito de este estudio fue valorar la eficacia del aloinjerto en las fracturas
de platillo tibial como material de relleno para los defectos metafisarios, así como una alternativa
que disminuya la morbilidad (dolor en el lugar de la extracción, infección del mismo,
alargamiento del tiempo de intervención quirúrgica...) sin que disminuya la capacidad de integración
ósea y se comprometa la realización de una movilización precoz. Para ello se han revisado
trece casos clínicos en los que se ha practicado una reducción anatómica, fijación interna
y relleno con aloinjerto procedente del Banco de Huesos, apreciándose una integración ósea
del mismo en el plazo aproximado de 10 semanas. Valorando los resultados con arreglo a los
criterios de Honkonen hemos obtenido 7 casos con excelente resultado, 4 casos con bueno
y 2 casos con mal resultado. Consideramos que el aloinjerto óseo es una eficaz alternativa en
el relleno de los defectos metafisarios óseos asociados a las fracturas de platillo tibial.The purpose of this study was to assess the efficacy of allograft bone as filling
agent of metaphyseal defects in tibial plateau fractures, trying to find an effective alternative
to decrease the morbility (donor site complications: painful, infection, increased surgical time...),
without affecting bone ingrowth and early motion. A total of 13 cases treated by anatomic open
reduction, rigid internal fixation and filling with frozen allograft bone have been reviewed. When
evaluating results according to Honkonen, excellent results were found in 7 cases, good results
in 4 and bad results in 2. Allograft bone seems to be an effective alternative for repairing
metaphyseal defects associated with tibial plateau fractures
Relationship Between the Quorum Network (Sensing/Quenching) and Clinical Features of Pneumonia and Bacteraemia Caused by A. baumannii
Acinetobacter baumannii (Ab) is one of the most important pathogens associated
with nosocomial infections, especially pneumonia. Interest in the Quorum network,
i.e., Quorum Sensing (QS)/Quorum Quenching (QQ), in this pathogen has grown
in recent years. The Quorum network plays an important role in regulating diverse
virulence factors such as surface motility and bacterial competition through the
type VI secretion system (T6SS), which is associated with bacterial invasiveness.
In the present study, we investigated 30 clinical strains of A. baumannii isolated in
the “II Spanish Study of A. baumannii GEIH-REIPI 2000-2010” (Genbank Umbrella
Bioproject PRJNA422585), a multicentre study describing the relationship between the
Quorum network in A. baumannii and the development of pneumonia and associated
bacteraemia. Expression of the aidA gene (encoding the AidA protein, QQ enzyme) was
lower (P < 0.001) in strains of A. baumannii isolated from patients with bacteraemic
pneumonia than in strains isolated from patients with non-bacteraemic pneumonia.
Moreover, aidA expression in the first type of strain was not regulated in the presence
of environmental stress factors such as the 3-oxo-C12-HSL molecule (substrate of AidA
protein, QQ activation) or H2O2 (inhibitor of AidA protein, QS activation). However, in the
A. baumannii strains isolated from patients with non-bacteraemic pneumonia, aidA gene
expression was regulated by stressors such as 3-oxo-C12-HSL and H2O2. In an in vivo
Galleria mellonella model of A. baumannii infection, the A. baumannii ATCC 17978 strain
was associated with higher mortality (100% at 24 h) than the mutant, abaI-deficient, strain (carrying a synthetase enzyme of Acyl homoserine lactone molecules) (70% at 24 h).
These data suggest that the QS (abaR and abaI genes)/QQ (aidA gene) network affects
the development of secondary bacteraemia in pneumonia patients and also the virulence
of A. baumannii.National Plan for Scientific ResearchTechnological Development and Innovation PI16/01163ISCIII-Deputy General Directorate for Evaluation and Promotion of Research-European Regional Development Fund A way of Making EuropeInstituto de Salud Carlos IIIMiguel Servet Research Programme SERGAS and ISCIIIXunta de Galicia (GAIN, Axencia de Innovación
Experimental Indicators of Accretion Processes in Active Galactic Nuclei
Bright Active Galactic Nuclei are powered by accretion of mass onto the super
massive black holes at the centers of the host galaxies. For fainter objects
star formation may significantly contribute to the luminosity. We summarize
experimental indicators of the accretion processes in Active Galactic Nuclei
(AGN), i.e., observable activity indicators that allow us to conclude on the
nature of accretion. The Galactic Center is the closest galactic nucleus that
can be studied with unprecedented angular resolution and sensitivity.
Therefore, here we also include the presentation of recent observational
results on Sagittarius A* and the conditions for star formation in the central
stellar cluster. We cover results across the electromagnetic spectrum and find
that the Sagittarius A* (SgrA*) system is well ordered with respect to its
geometrical orientation and its emission processes of which we assume to
reflect the accretion process onto the super massive black hole.Comment: 16 pages, 4 figures, conference proceeding: Accretion Processes in
Cosmic Sources - APCS2016 - 5-10 September 2016, Saint Petersburg, Russi
Promoting prosocial behaviour among Colombian adolescents: the evaluation of a universal school-based program using a multi-informant perspective
The present study evaluated the efficacy of an Italian school-based intervention programme adapted in three Colombian sites (Medellín, Manizales, and Santa Marta) in promoting prosocial behaviour among adolescents. Using a pre-test-post-test design with a multi-informant approach, the present study assessed 451 students (Mage = 12.77, SD = 1.06) of the intervention group and 428 students (Mage = 12.64, SD = 1.01) by using self-report and peer rating measures of prosocial behaviour. After establishing the measurement invariance across time and informants, a latent difference score model showed the positive effect of the intervention programme in improving prosocial behaviour evaluated by peers (Cohen’s d = .379) among Colombian adolescents, across all three sites. Implications of the study will be discussed
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