Abstract
Star formation rate density, Σ
SFR
, has shown a remarkable correlation with both components of the baryonic mass kiloparsec scales (i.e., the stellar mass density and molecular gas mass ...density, Σ
*
and Σ
mol
, respectively) for galaxies in the nearby universe. In this study, we propose an empirical relation between Σ
SFR
and the baryonic mass surface density (Σ
b
= Σ
mol,Av
+ Σ
*
, where Σ
mol,Av
is the molecular gas derived from the optical extinction,
A
V
) at kiloparsec scales using the spatially resolved properties of the MaNGA survey, the largest sample of galaxies observed via integral field spectroscopy (∼8400 objects). We find that Σ
SFR
tightly correlates with Σ
b
. Furthermore, we derive an empirical relation between Σ
SFR
and a second-degree polynomial of Σ
b
, yielding a one-to-one relation between these two observables. Both Σ
b
and its polynomial form show a stronger correlation and smaller scatter with respect to Σ
SFR
than the relations derived using the individual components of Σ
b
. Our results suggest that these three parameters are indeed physically correlated, suggesting a scenario in which the two components of the baryonic mass regulate the star formation activity at kiloparsec scales.
Abstract
We present an extensive exploration of the impact of 29 physical parameters in the oxygen abundance for a sample of 299 star-forming galaxies extracted from the extended Calar Alto Legacy ...Integral Field Area Survey sample. We corroborate that the stellar mass is the physical parameter that better traces the observed oxygen abundance (i.e., the mass–metallicity relation; MZR), while other physical parameters could play a potential role in shaping this abundance, but with a lower significant impact. We find that the functional form that best describes the MZR is a third-order polynomial function. From the residuals between this best functional form and the MZR, we find that once considered the impact of the mass in the oxygen abundance, the other physical parameters do not play a significant secondary role in shaping the oxygen abundance in these galaxies (including the gas fraction or the star formation rate). Our analysis suggests that the origin of the MZR is related to the chemical enrichment evolution of the interstellar medium due, most likely, to the buildup of stellar mass in these star-forming galaxies.
Síndrome de Wooblers en un caballo Betancur Hurtado, César; Álvarez, P. Jaime; Cardona Álvarez, Antonio José
Revista MVZ Córdoba,
2013, Letnik:
18, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A case of Wooblers syndrome is described in a complete male 14-year-old horse from the town of Cereté (Cordoba, Colombia). This condition is also known as equine cervical vertebral stenotic ...myelopathy (CVSM), which is a disease characterized by developmental cervical spinal canal stenosis resulting in intermittent or continuous compression of the spinal cord. This patient showed to have signs of incoordination which included stumbling, symmetrical ataxia, paresis or weakness, spasticity and loss of propioception, particularly in the hindquarters, so that radiology was performed to detect cervical spinal canal stenosis at the level of the cervical vertebrae C4. These findings are related as Wooblers syndrome.
Se describe un caso de síndrome de Wooblers en un caballo, macho entero, de 14 años de edad, procedente del municipio de Cereté (Córdoba, Colombia). Esta patología es también conocida en equinos como mielopatía estenótica vertebral cervical (MEVC), la cual es una enfermedad del desarrollo caracterizada por estenosis del canal vertebral cervical resultando en compresión intermitente o continua de la médula espinal. A este paciente se le detectaron signos de incoordinación con tropiezos, ataxia simétrica, paresia o debilidad, espasticidad y pérdida de la propiocepción, principalmente en los miembros posteriores, por lo que se le realizó radiología cervical detectando estenosis de canal medular a nivel de la vértebra cervical C4. Estos hallazgos obedecen principalmente al síndrome de Wooblers.
ABSTRACT
We present a new characterization of the relations between star-formation rate, stellar mass, and molecular gas mass surface densities at different spatial scales across galaxies (from ...galaxy-wide to kpc scales). To do so, we make use of the largest sample combining spatially resolved spectroscopic information with CO observations, provided by the Extragalactic Database for Galaxy Evolution (EDGE)–Calar Alto Legacy Integral Field Area (CALIFA) survey, together with new single-dish CO observations obtained by the Atacama Pathfinder Experiment (APEX). We show that these relations are the same at the different scales explored, sharing the same distributions for the explored data, with similar slope, intercept, and scatter (when characterized by a simple power law). From this analysis, we propose that these relations are the projection of a single relation between the three properties that follows a distribution described well by a line in three-dimensional parameter space. Finally, we show that observed secondary relations between the residuals and the parameters considered are explained fully by the correlation between the uncertainties, and therefore have no physical origin. We discuss these results in the context of the hypothesis of self-regulation of the star-formation process.
Star formation rate density, \(\Sigma_{\rm SFR}\), has shown a remarkable correlation with both components of the baryonic mass at kpc scales (i.e., the stellar mass density, and the molecular gas ...mass density; \(\Sigma_{\ast}\), and \(\Sigma_{\rm mol}\), respectively) for galaxies in the nearby Universe. In this study we propose an empirical relation between \(\Sigma_{\rm SFR}\) and the baryonic mass surface density (\(\Sigma_{\rm b}\) =\(\Sigma_{\rm mol,Av}\) + \(\Sigma_{\ast}\); where \(\Sigma_{\rm mol,Av}\) is the molecular gas density derived from the optical extinction, Av) at kpc scales using the spatially-resolved properties of the MaNGA survey - the largest sample of galaxies observed via Integral Field Spectroscopy (IFS, \(\sim\) 8400 objects). We find that \(\Sigma_{\rm SFR}\) tightly correlates with \(\Sigma_{\rm b}\). Furthermore, we derive an empirical relation between the \(\Sigma_{\rm SFR}\) and a second degree polynomial of \(\Sigma_{\rm b}\) yielding a one-to-one relation between these two observables. Both, \(\Sigma_{\rm b}\) and its polynomial form show a stronger correlation and smaller scatter with respect to \(\Sigma_{\rm SFR}\) than the relations derived using the individual components of \(\Sigma_{\rm b}\). Our results suggest that indeed these three parameters are physically correlated, suggesting a scenario in which the two components of the baryonic mass regulate the star-formation activity at kpc scales.
Aim: Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their ...environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change. Location: Mediterranean terrestrial ecosystems. Methods: This article revisits the research priorities proposed in a 1998 assessment. Results: A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest-atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology. Main conclusions: (1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional-and global-scale models that are more tightly connected with largescale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use.
Traveller’s diarrhoea (TD) is the most common illness reported in international travellers. TD is caused by a wide range of pathogens, including bacteria, viruses and parasites. Multiplex PCR assays ...can be especially useful for studying the aetiology of TD. The first objective of this study was to evaluate the utility of the commercially available multiplex PCR (xTAG® Gastrointestinal Pathogen Panel (GPP)) for the diagnosis of TD. A total of 185 stool specimens obtained from 174 patients were processed using the GPP assay. This test detected 86 pathogens in 67 stool samples (67/185, 36.2%). Sixteen pathogens out of 86 were also detected by routine testing. The remaining pathogens (n = 70) required further confirmation by alternative techniques. Finally, 60 out of 70 pathogens were confirmed. The second objective of this study was to analyse the aetiology of TD based on the results obtained by the GPP test and routine methods. The primary pathogens causing TD were Shigella (24.2%) followed by enterotoxigenic Escherichia coli (ETEC) (23.2%), enteroaggregative E. coli (14.7%) and Giardia (13.7%). Significant regional differences were observed for ETEC with 19.4% of TD cases acquired in Africa, 11.3% in Asia and none in South Central (SC) America (p 0.01), Giardia was found in 1.5% of cases among those who had travelled to Africa, 14.1% of those who had travelled to Asia and 3% of those who had travelled to SC America (p 0.01). In conclusion, the GPP test improved the detection of enteropathogens and allowed better assessment of the aetiology of TD.
We present an extensive exploration of the impact of 29 physical parameters in the oxygen abundance for a sample of 299 star-forming galaxies extracted from the extended CALIFA sample. We corroborate ...that the stellar mass is the physical parameter that better traces the observed oxygen abundance (i.e., the mass-metallicity relation, MZR), while other physical parameters could play a potential role in shaping this abundance, but with a lower significant impact. We find that the functional form that best describes the MZR is a third-order polynomial function. From the residuals between this best functional form and the MZR, we find that once considered the impact of the mass in the oxygen abundance, the other physical parameters do not play a significant secondary role in shaping the oxygen abundance in these galaxies (including the gas fraction or the star formation rate). Our analysis suggests that the origin of the MZR is related to the chemical enrichment evolution of the interstellar medium due, most likely, to the build-up of stellar mass in these star-forming galaxies.
We present a new characterization of the relations between star-formation
rate, stellar mass and molecular gas mass surface densities at different
spatial scales across galaxies (from galaxy wide to ...kpc-scales). To do so we
make use of the largest sample combining spatially-resolved spectroscopic
information with CO observations, provided by the EDGE-CALIFA survey, together
with new single dish CO observations obtained by APEX. We show that those
relations are the same at the different explored scales, sharing the same
distributions for the explored data, with similar slope, intercept and scatter
(when characterized by a simple power-law). From this analysis, we propose that
these relations are the projection of a single relation between the three
properties that follows a distribution well described by a line in the
three-dimension parameter space. Finally, we show that observed secondary
relations between the residuals and the considered parameters are fully
explained by the correlation between the uncertainties, and therefore have no
physical origin. We discuss these results in the context of the hypothesis of
self-regulation of the star-formation process.
PDF
