With the proliferation of social networks and blogs, the Internet is increasingly being used to disseminate personal health information rather than just as a source of information. In this paper we ...exploit the wealth of user-generated data, available through the micro-blogging service Twitter, to estimate and track the incidence of health conditions in society. The method is based on two stages: we start by extracting possibly relevant tweets using a set of specially crafted regular expressions, and then classify these initial messages using machine learning methods. Furthermore, we selected relevant features to improve the results and the execution times. To test the method, we considered four health states or conditions, namely flu, depression, pregnancy and eating disorders, and two locations, Portugal and Spain. We present the results obtained and demonstrate that the detection results and the performance of the method are improved after feature selection. The results are promising, with areas under the receiver operating characteristic curve between 0.7 and 0.9, and f-measure values around 0.8 and 0.9. This fact indicates that such approach provides a feasible solution for measuring and tracking the evolution of health states within the society.
In large-scale cosmological hydrodynamic simulations simplified sub-grid models for gas accretion on to black holes and AGN feedback are commonly used. Such models typically depend on various free ...parameters, which are not well constrained. We present a new advanced model containing a more detailed description of AGN feedback, where those parameters reflect the results of recent observations. The model takes the dependence of these parameters on the black hole properties into account and describes a continuous transition between the feedback processes acting in the so-called radio-mode and quasar-mode. In addition, we implement a more detailed description of the accretion of gas on to black holes by distinguishing between hot and cold gas accretion. Our new implementations prevent black holes from gaining too much mass, particularly at low redshifts, so that our simulations are successful in reproducing the observed present-day black hole mass function. Our new model also suppresses star formation in massive galaxies slightly more efficiently than many state-of-the-art models. Therefore, the simulations that include our new implementations produce a more realistic population of quiescent and star-forming galaxies compared to recent observations, even if some discrepancies remain. In addition, the baryon conversion efficiencies in our simulation are – except for the high-mass end – consistent with observations presented in the literature over the mass range resolved by our simulations. Finally, we discuss the significant impact of the feedback model on the low-luminous end of the AGN luminosity function.
Conspectus Although there has been for the past 20 years great interest in the synthesis and use of metal nanoparticles, little attention has been paid to the complexity of the surface of these ...species. In particular, the different aspects concerning the ligands present, their location, their mode of binding, and their dynamics have been little studied. Our group has started in the early 1990s an investigation of the surface coordination chemistry of ruthenium and platinum nanoparticles but at that time with a lack of adequate techniques to fulfill our ambition. Over 10 years later, we went back to this problem and could obtain a more precise vision of the surface species. This Account is centered on ruthenium chemistry. This metal has been the most studied in our group, first thanks to the availability of a precursor, Ru(cyclooctadiene)(cyclooctatriene) (Ru(COD)(COT)), which possesses the ability to decompose in very mild conditions without leaving residues on the resulting nanoparticles and second because of the absence of magnetic perturbations (Knight shift, paramagnetism, ferromagnetism, etc.), which has allowed the use of solution and solid state NMR. In this respect, it has been possible to evidence the presence of a high concentration of hydrides on the surface of these particles, to study their dynamics, and to show that since the polarity of the Ru–H bond is similar to that of the C–H bond, a Ru/H NP would behave as a big lipophilic entity. The second point was to characterize the coordination of ancillary ligands. This has been achieved for different ligands, in particular phosphines and carbenes, which made possible the study of the modification of NP reactivity induced by surface ligands. This led to the conclusion that the presence of surface ligands can benefit both the activity of NP catalysts and their selectivity. If it was expected that the selectivity could be modulated, the promoting effect from the presence of ligands on, for example, arene or CO hydrogenation was totally unexpected. Playing with poison atoms (Sn, Fe, etc.) or ligands (CO) may allow us to play with the reactivity of the NPs to make them more selective for selected reactions. Finally, the search for specific ligands for nanoparticles is still in its infancy, but some examples have been found as have specific reactions of nanoparticles. Obviously arene hydrogenation and CO hydrogenation were well-known in heterogeneous catalysis, but we could demonstrate that they can be carried out in very mild conditions on ligand stabilized RuNPs. On the other hand, the enantiospecific C–H activation leading to enantioselective labeling of large organic or biomolecules or the C–C bond cleavage in mild conditions were both unexpected. There is still much work to perform for reaching the degree of control on nanoparticles that is presently achieved in organometallic molecular chemistry, but this work shows that it is possible.
The nuclear radio emission of low-luminosity active galactic nuclei (LLAGNs) is often associated with unresolved cores. In this paper we show that most LLAGNs present extended jet radio emission when ...observed with sufficient angular resolution and sensitivity. They are thus able to power, at least, parsec-scale radio jets. To increase the detection rate of jets in LLAGNs, we analyze subarcsecond resolution data of three low-ionization nuclear emission regions. This yields the detection of extended jet-like radio structures in NGC 1097 and NGC 2911 and the first resolved parsec-scale jet of NGC 4594 (Sombrero). The three sources belong to a sample of nearby LLAGNs for which high-spatial-resolution spectral energy distribution of their core emission is available. This allows us to study their accretion rate and jet power (Q sub(jet)) without drawing on (most) of the ad hoc assumptions usually considered in large statistical surveys. We find that those LLAGNs with large-scale radio jets (> 100 pc) have Q sub(jet) > 10 super(42) erg s super(-1), while the lowest Q sub(jet) correspond to those LLAGNs with parsec-scale (< or =, slant100 pc) jets. The Q sub(jet) is at least as large as the radiated bolometric luminosity for all LLAGN, in agreement with previous statistical studies. Our detection of parsec-scale jets in individual objects further shows that the kinematic jet contribution is equally important in large- or parsec-scale objects. We also find that the Eddington-scaled accretion rate is still highly sub-Eddingtonian (<10 super(-4)) when adding the Q sub(jet) to the total emitted luminosity (radiated plus kinetic). This indicates that LLAGNs are not only inefficient radiators but that they also accrete inefficiently or are very efficient advectors.
Fucoxanthin is a pigment present in diverse marine organisms such as micro and macro-algae. The most relevant source of fucoxanthin has been described to be the group of the brown macroalgae, also ...known as Phaeophyceae. The presence of the fucoxanthin, a xanthophyll, found as an accessory pigment in the chloroplasts of the brown algae is responsible for providing them their characteristic color. The market size of this carotenoid, expected to reach US$ 120 million by 2022, reflects its industrial importance, especially remarkable as a food or cosmetic ingredient.
Therefore, it is critical to recognize the main sources of fucoxanthin as well as the most efficient extraction and purification methods that allow obtaining the best production ratio for such a valuable molecule. Throughout this review very different preventive properties of the fucoxanthin have been included, such as antioxidant, anticancer, antiangiogenic, anti-inflammatory, cytoprotective, antiobesity, neuroprotective and its skin protective effects. The stability, bioavailability and toxicity of the fucoxanthin have also been reviewed through diverse biological, in vitro and in vivo assays.
Thus, the main aim of this work is to provide a wide and global vision of the fucoxanthin in terms of productive species, efficient recovery techniques and multiple industrial applications.
The main sources of fucoxanthin are brown algae (Phaeophytes) and some microalgae. Several techniques have been employed to extract this compound, such as maceration extraction (ME), enzyme assisted extraction (EAE), microwave assisted extraction (MAE), pressurized liquid extraction (PLE) or supercritical fluid extraction (SFE). Following the extraction, the identification step has been carried out using different chromatographic and spectroscopic techniques. Fucoxanthin has gained attention in the last decades, due to the wide variety of attributed beneficial activities, such as antioxidant, anti-inflammatory, anticancer or neuroprotective effects. These bioactivities are interesting for its diverse applications in the industry, including the development of innovative pharmaceutical, cosmetic and food products. Display omitted
•Review of fucoxanthin main matrixes and bioactive properties.•Approximation to fucoxanthin extraction and quantification methods.•Review of fucoxanthin stability, bioavailability and toxicity in diverse biological assays.•Content of fucoxanthin in micro and macroalgae (notably in chloroplasts of brown algae).•Fucoxanthin industrial importance (US$ 120 million by 2022) as ingredient (food or cosmetic).
Enterococci are Gram-positive bacteria that are found in plants, soil and as commensals of the gastrointestinal tract of humans, mammals, and insects. Despite their commensal nature, they have also ...become globally important nosocomial pathogens. Within the genus Enterococcus, Enterococcus faecium, and Enterococcus faecalis are clinically most relevant. In this review, we will discuss how E. faecium and E. faecalis have evolved to become a globally disseminated nosocomial pathogen. E. faecium has a defined sub-population that is associated with hospitalized patients and is rarely encountered in community settings. These hospital-associated clones are characterized by the acquisition of adaptive genetic elements, including genes involved in metabolism, biofilm formation, and antibiotic resistance. In contrast to E. faecium, clones of E. faecalis isolated from hospitalized patients, including strains causing clinical infections, are not exclusively found in hospitals but are also present in healthy individuals and animals. This observation suggests that the division between commensals and hospital-adapted lineages is less clear for E. faecalis than for E. faecium. In addition, genes that are reported to be associated with virulence of E. faecalis are often not unique to clinical isolates, but are also found in strains that originate from commensal niches. As a reflection of more ancient association of E. faecalis with different hosts, these determinants Thus, they may not represent genuine virulence genes but may act as host-adaptive functions that are useful in a variety of intestinal environments. The scope of the review is to summarize recent trends in the emergence of antibiotic resistance and explore recent developments in the molecular epidemiology, population structure and mechanisms of adaptation of E. faecium and E. faecalis.
We present archival high-spatial-resolution VLA and VLBA data of the nuclei of seven of the nearest and brightest Seyfert galaxies in the Southern Hemisphere. At VLA resolution (∼0.1 arcsec), the ...nuclei of the Seyfert galaxies are unresolved, with the exception of MCG-5-23-16 and NGC 7469, which show a core–jet structure. Three Seyfert nuclei are surrounded by diffuse radio emission related to star-forming regions. VLBA observations with parsec-scale resolution demonstrate that in MRK 1239 the nucleus is clearly resolved into two components separated by ∼30 pc, whereas the nucleus of NGC 3783 is unresolved. Further comparison between VLA and VLBA data of these two sources shows that the flux density at parsec scales is only 20 per cent of that measured by the VLA. This suggests that the radio emission is not concentrated in a single central component, as in elliptical radio galaxies, and an additional low-surface-brightness component must be present. A comparison of Seyfert nuclei with different radio spectra shows that the ‘presence’ of undetected flux on a milliarcsecond scale is common in steep-spectrum objects, whereas in flat-spectrum objects essentially all the radio emission is recovered. In the steep-spectrum objects, this ‘missing’ flux probably results from non-thermal radiation related to active galactic nuclei, perhaps from a jet that is disrupted in Seyfert galaxies because of the denser environment of their spiral hosts.
•The extracts of Arbutus unedo L. fruits showed high concentration of anthocyanins.•Two different techniques were compared to maximize the extraction.•Heat extraction proved to be the most effective ...method.•Optimal conditions of variables to maximize anthocyanins extraction were found.
The goal of this study was to compare anthocyanin extraction from Arbutus unedo L. fruits, by using two techniques assisted by different energy sources, heat and ultrasound. In order to obtain the conditions that maximize anthocyanin extraction, a response surface methodology was applied using the circumscribed central composite design of three variables with five levels. Three anthocyanin compounds were identified by HPLC-DAD-ESI/MS, being cyanidin-3-glucoside the main molecule. Heat assisted extraction proved to be the most effective method at 5 min, 90 °C and 80% of ethanol, yielding 51.2% of extract, with a total anthocyanin content of 382.4 µg/g dried fruit, and 744.6 µg/g extract. These response values were slightly improved by studying the solid/liquid effect at the optimal conditions in dose-response format, showing steady extraction values from 5 to 40 g/L. Results show the possibility of using A. unedo fruits as a source of anthocyanin compounds for industrial applications.
We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec ( ∼ 32 pc) across the electromagnetic spectrum. Two separate, quiescent, and active states ...are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical active galactic nuclei or a radiatively inefficient accretion source. We show that the emission from a jet gives an excellent representation of the core of M87 core covering ten orders of magnitude in frequency for both the active and the quiescent phases. The inferred total jet power is, however, one to two orders of magnitude lower than the jet mechanical power reported in the literature. The maximum luminosity of a thin accretion disc allowed by the data yields an accretion rate of < 6 × 10− 5 M⊙ yr− 1, assuming 10 per cent efficiency. This power suffices to explain M87 radiative luminosity at the jet frame, it is however two to three order of magnitude below that required to account for the jet's kinetic power. The simplest explanation is variability, which requires the core power of M87 to have been two to three orders of magnitude higher in the last 200 yr. Alternatively, an extra source of power may derive from black hole spin. Based on the strict upper limit on the accretion rate, such spin power extraction requires an efficiency an order of magnitude higher than predicted from magnetohydrodynamic simulations, currently in the few hundred per cent range.
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