427 research outputs found
The spatially-resolved star formation histories of CALIFA galaxies: Implications for galaxy formation
This paper presents the spatially resolved star formation history (SFH) of
nearby galaxies with the aim of furthering our understanding of the different
processes involved in the formation and evolution of galaxies. To this end, we
apply the fossil record method of stellar population synthesis to a rich and
diverse data set of 436 galaxies observed with integral field spectroscopy in
the CALIFA survey. The sample covers a wide range of Hubble types, with stellar
masses ranging from to . Spectral
synthesis techniques are applied to the datacubes to retrieve the spatially
resolved time evolution of the star formation rate (SFR), its intensity
(), and other descriptors of the 2D-SFH in seven bins of
galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd), and five bins of stellar
mass. Our main results are: a) Galaxies form very fast independently of their
current stellar mass, with the peak of star formation at high redshift (). Subsequent star formation is driven by and morphology, with less
massive and later type spirals showing more prolonged periods of star
formation. b) At any epoch in the past the SFR is proportional to ,
with most massive galaxies having the highest absolute (but lowest specific)
SFRs. c) While nowadays is similar for all spirals, and
significantly lower in early type galaxies (ETG), in the past scales well with morphology. The central regions of today's ETGs are
where reached the highest values (Gyrpc), similar to those measured in high redshift
star forming galaxies. d) The evolution of in Sbc systems
matches that of models for Milky-Way-like galaxies, suggesting that the
formation of a thick disk may be a common phase in spirals at early epochs.Comment: 21 pages, 11 figures, 1 table, accepted for publication in Astronomy
& Astrophysics, abstract abridged for arXiv submissio
Insights on the stellar mass-metallicity relation from the CALIFA survey
We use spatially and temporally resolved maps of stellar population
properties of 300 galaxies from the CALIFA integral field survey to investigate
how the stellar metallicity (Z*) relates to the total stellar mass (M*) and the
local mass surface density (*) in both spheroidal and disk dominated
galaxies. The galaxies are shown to follow a clear stellar mass-metallicity
relation (MZR) over the whole 10 to 10 M range. This
relation is steeper than the one derived from nebular abundances, which is
similar to the flatter stellar MZR derived when we consider only young stars.
We also find a strong relation between the local values of * and Z* (the
ZR), betraying the influence of local factors in determining Z*. This
shows that both local (*-driven) and global (M*-driven) processes are
important in determining the metallicity in galaxies. We find that the overall
balance between local and global effects varies with the location within a
galaxy. In disks, * regulates Z*, producing a strong ZR whose
amplitude is modulated by M*. In spheroids it is M* who dominates the physics
of star formation and chemical enrichment, with * playing a minor,
secondary role. These findings agree with our previous analysis of the star
formation histories of CALIFA galaxies, which showed that mean stellar ages are
mainly governed by surface density in galaxy disks and by total mass in
spheroids.Comment: 6 pages, 3 figures, accepted for publication in ApJ
A decade of GRB follow-up by BOOTES in Spain (2003-2013)
This article covers ten years of GRB follow-ups by the Spanish BOOTES
stations: 71 follow-ups providing 23 detections. Follow-ups by BOOTES-1B from
2005 to 2008 were given in the previous article, and are here reviewed,
updated, and include additional detection data points as the former article
merely stated their existence. The all-sky cameras CASSANDRA have not yet
detected any GRB optical afterglows, but limits are reported where available
Comparative study of the use of Doxycycline and Oxytetracycline to treat Anaplasmosis in fattening lambss
Lamb icteric carcasses condemnation due to Anaplasma ovis is causing relevant economic losses. A comparative study was developed on the effects of different antibiotics to treat ovine anaplasmosis in fattening lambs. A total of 100 A. ovis naturally infected lambs were selected and randomly divided into four groups of 25 lambs: Group ID, treated with injectable doxycycline; Group OD, oral doxycycline; Group O, injectable oxytetracycline; and Group C, untreated animals for the control group. Clinical, haematological, and molecular analyses were performed before the treatment and 12 and 45 days after the beginning of the treatments, and carcass condemnation was followed after slaughter. The A. ovis bacterial load was high before the treatments in the four groups and decreased significantly 45 days after treatment in the ID and O Groups (p < 0.001). The parameters that were related to haemolysis showed similar results. At the abattoir, 15 out of the 47 examined carcasses were condemned; 7 of C Group, 6 of OD Group, 2 of O Group, and 0 of ID Group. It can be concluded that injectable doxycycline and oxytetracycline significantly reduce A. ovis bacterial load in blood and carcass condemnation at the abattoir. Further studies are needed in order to confirm these encouraging findings
Antibody response in patients admitted to the hospital with suspected SARS-CoV-2 infection: results from a multicenter study across Spain
Aim: To evaluate the serological response against SARS-CoV-2 in a multicenter study representative of the Spanish COVID pandemic.
Methods: IgG and IgM + IgA responses were measured on 1466 samples from 1236 Spanish COVID-19 patients admitted to the hospital, two commercial ELISA kits (Vircell SL, Spain) based on the detection of antibodies against the viral spike protein and nucleoprotein, were used.
Results: Approximately half of the patients presented antibodies (56.8% were IgM + IgA positive and 43.0% were IgG positive) as soon as 2 days after the first positive PCR result. Serological test positivity increased with time from the PCR test, and 10 days after the first PCR result, 91.5% and 88.0% of the patients presented IgM + IgA and IgG antibodies, respectively.
Conclusion: The high values of sensitivity attained in the present study from a relatively early period of time after hospitalization support the use of the evaluated serological assays as supplementary diagnostic tests for the clinical management of COVID-19
Ipsilesional Hippocampal GABA Is Elevated and Correlates With Cognitive Impairment and Maladaptive Neurogenesis After Cortical Stroke in Mice.
BACKGROUND
Cognitive dysfunction is a frequent stroke sequela, but its pathogenesis and treatment remain unresolved. Involvement of aberrant hippocampal neurogenesis and maladaptive circuitry remodeling has been proposed, but their mechanisms are unknown. Our aim was to evaluate potential underlying molecular/cellular events implicated.
METHODS
Stroke was induced by permanent occlusion of the middle cerebral artery occlusion in 2-month-old C57BL/6 male mice. Hippocampal metabolites/neurotransmitters were analyzed longitudinally by in vivo magnetic resonance spectroscopy. Cognitive function was evaluated with the contextual fear conditioning test. Microglia, astrocytes, neuroblasts, interneurons, γ-aminobutyric acid (GABA), and c-fos were analyzed by immunofluorescence.
RESULTS
Approximately 50% of mice exhibited progressive post-middle cerebral artery occlusion cognitive impairment. Notably, immature hippocampal neurons in the impaired group displayed more severe aberrant phenotypes than those from the nonimpaired group. Using magnetic resonance spectroscopy, significant bilateral changes in hippocampal metabolites, such as myo-inositol or N-acetylaspartic acid, were found that correlated, respectively, with numbers of glia and immature neuroblasts in the ischemic group. Importantly, some metabolites were specifically altered in the ipsilateral hippocampus suggesting its involvement in aberrant hippocampal neurogenesis and remodeling processes. Specifically, middle cerebral artery occlusion animals with higher hippocampal GABA levels displayed worse cognitive outcome. Implication of GABA in this setting was supported by the amelioration of ischemia-induced memory deficits and aberrant hippocampal neurogenesis after blocking pharmacologically GABAergic neurotransmission, an intervention which was ineffective when neurogenesis was inhibited. These data suggest that GABA exerts its detrimental effect, at least partly, by affecting morphology and integration of newborn neurons into the hippocampal circuits.
CONCLUSIONS
Hippocampal GABAergic neurotransmission could be considered a novel diagnostic and therapeutic target for poststroke cognitive impairment.S
Trehalose-based siamese twin amphiphiles with tunable self-assembling, DNA nanocomplexing and gene delivery properties
An original family of multivalent vectors encompassing gemini and facial amphiphilicity, namely cationic Siamese twin surfactants, has been prepared fromthe disaccharide trehalose; molecular engineering lets us modulate the self-assembling properties and the topology of the nanocomplexes with plasmid DNA for efficient gene delivery in vitro and in vivo
Adiciones y revisiones al Atlas de la flora vascular silvestre de Burgos
Se mencionan 31 táxones con citas y/o comentarios referidos a su existencia en la provincia de Burgos. De ellos 8 suponen una novedad para el catálogo provincial.Additions and revisions for the “Atlas de la flora vascular silvestre de Burgos”, IX. 31 Taxa with either quotations or remarks, related to their existence within the province of Burgos, are mentioned. 8 out of these aforementioned ones mean a novelty value for the provincial catalogue
The ionized gas in the central region of NGC 5253: 2D mapping of the physical and chemical properties
ABRIDGED: NGC5253 was previously studied by our group with the aim to
elucidate in detail the starburst interaction processes. Some open issues
regarding the 2D structure of the main properties of the ionized gas remain to
be addressed. Using IFS data obtained with FLAMES, we derived 2D maps for
different tracers of electron density (n_e), electron temperature (T_e) and
ionization degree. The maps for n_e as traced by several line ratios are
compatible with a 3D stratified view of the nebula with the highest n_e in the
innermost layers and a decrease of n_e outwards. To our knowledge, this is the
first time that a T_e map based on [SII] lines for an extragalactic object is
presented. The joint interpretation of our two T_e maps is consistent with a
T_e structure in 3D with higher temperatures close to the main ionizing source
surrounded by a colder and more diffuse component. The highest ionization
degree is found at the peak of emission for the gas with relatively high
ionization in the main GHIIR and lower ionization degree delineating the more
extended diffuse component. Abundances for O, Ne and Ar are constant over the
mapped area within <0.1 dex. The mean 12+log(O/H) is 8.26 while the relative
abundances of log(N/O), log(Ne/O) and log(Ar/O) were \sim-1.32, -0.65 and
-2.33, respectively. There are two locations with enhanced N/O. The first
(log(N/O)\sim-0.95) is associated to two super star clusters. The second
(log(N/O)\sim-1.17), reported here for the first time, is associated to two
moderately massive (2-4x10^4 M_sun) and relatively old (\sim10 Myr) clusters. A
comparison of the N/O map with those produced by strong line methods supports
the use of N2O2 over N2S2 in the search for chemical inhomogeneities within a
galaxy. The results on the localized nitrogen enhancement were used to compile
and discuss the factors that affect the complex relationship between Wolf-Rayet
stars and N/O excess.Comment: 16 pages, 14 figures, accepted for publication in A&
Doñana, diversidad y ciencia
144 páginasLa biodiversidad es más que la suma de los elementos que componen el mundo vivo; también son biodiversidad las relaciones entre esos elementos, los procesos ecológicos que hacen posible su existencia y los procesos evolutivos que los han originado. […] Los seres humanos necesitamos a la biodiversidad más que ella a nosotros, ya que es la responsable de que la Tierra funcione de una manera satisfactoria. […] El entramado de la vida se ocupa de regular la composición de la atmósfera (y con ella, el clima), de depurar el aire y el agua, de hacer fértil al suelo, de evitar riadas y avalanchas, de polinizar las cosechas, de reducir las plagas, etc. Por todo ello es indispensable conservar la biodiversidad, hoy amenazada.” (Miguel Delibes)
Doñana, diversidad y ciencia es un paseo conceptual por el espacio natural más emblemático de Europa. La esencia de un mito a través de decenas de fotografías… Un acercamiento respetuoso a la diversidad de sus conceptos, un paseo por la esencia de su historia y una curiosa aproximación a la ciencia que genera hoy en día. En este recorrido descubriremos el carácter distintivo de algunos de los parajes de la reserva, sus matices más interesantes, las texturas y las formas más sorprendentes de la naturaleza, sus colores y conjuntos, sus transformaciones en las últimas décadas y la influencia de la presencia humana en el privilegiado ecosistema de la Reserva Biológica de Doñana
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