691 research outputs found
BESDUI: A Benchmark for End-User Structured Data User Interfaces
The Semantic Web Community has invested significant research efforts in developing systems for Semantic Web search and exploration. But while it has been easy to assess the systems’ computational efficiency, it has been much harder to assess how well different semantic systems’ user interfaces help their users. In this article, we propose and demonstrate the use of a benchmark for evaluating such user interfaces, similar to the TREC benchmark for evaluating traditional search engines. Our benchmark includes a set of typical user tasks and a well-defined procedure for assigning a measure of performance on those tasks to a semantic system. We demonstrate its application to two such system, Virtuoso and Rhizomer. We intend for this work to initiate a community conversation that will lead to a generally accepted framework for comparing systems and for measuring, and thus encouraging, progress towards better semantic search and exploration tools
Necesidades percibidas por las familias acogedoras extensas
Los lazos afectivos en la familia extensa contribuyen a afirmar, en los niños y niñas, soportes cualitativos irremplazables por otro tipo de organización social, cuya eficacia se traduce en el compromiso, la inmediatez y la permanencia en el apoyo emocional que necesitan las familias nucleares y, en principio, sería la primera y mejor opción de acogimiento familiar para el menor que necesite de este recurso. En la familia extensa, generalmente ya existen unas relaciones, unos vínculos, que en la familia acogedora ajena (familia educadora) deben construirse desde el principio. El niño en familia extensa, en muchas ocasiones, ya conoce, ya confía en sus miembros, ello le permite al menor sentirse incluido en su entramado familiar y mantener el sentimiento de la preservación familiar y por tanto de la pertenencia. Para optimizar este recurso, entre otras cuestiones, el conocimiento de las necesidades percibidas, se considera uno de los pilares a considerar en la implementación de los programas de intervención social. Para ello, tanto las familias que acogen como los técnicos, por separado, han expresado su percepción acerca de la adecuación de los recursos a las necesidades de las familias acogedoras.Emotional relationships within extended families contribute to provide children with qualitative and irreplaceable support that no other social organization can give.The immediate consequences are commitment and permanence of the emotional support that nuclear families need and, in principle, this would be the first and best option for fostering children in need of this. In extended families there are usually already built-up relationships, connections that in the case of foster families (educating families) need to be built from scratch. In most of the cases, the kid fostered by an extended family already knows and trust his/her relatives and this allows the minor to feel less excluded from the family and preserve the feeling of belonging. To improve such resources it is important to acknowledge perceived needs which would be one of the main columns to implement and sustain social intervention programs. Not only those needs referred by the technicians in charge of the evolution and support of such processes, but also the needs of those families who take care of the minors everyday. For that, both technicians and families have expressed their feelings on the adaptation of the resources to the needs of the fostering families
Low temperature degradation behaviour of 10Ce-TZP/Al2O3 bioceramics obtained by microwave sintering technology
Zirconia is one of the most used ceramics, especially for biomedical applications, due to its exceptional mechanical properties. However, it is commonly known that its properties can be diminished owing to a low temperature degradation (LTD). This phenomenon consists on a spontaneous phase transformation, from tetragonal to monoclinic, under certain conditions, which is accelerated when the samples are exposed under high levels of humidity at a temperature range between 20-300 ºC. In addition to the fact that the monoclinic phase presents worse mechanical properties than the tetragonal one, there is a volume change of 4% between phases that gives rise to defects in the material as microcracks. Due to this reason, zirconia prostheses failed catastrophically inside the human body between 1999 and 2001 (1). Previous researches reveal that Al2O3 addition suppress the propagation of phase transformation (2). Thus, the aim of the present work is to study the hydrothermal ageing of zirconia doped with ceria and toughened with alumina (10Ce-TZP/Al2O3) composite, which has been sintered by microwave employing two different frequencies: 2.45 and 5.8 GHz. Microwave heating technology is based on the absorption of electromagnetic radiation by the material, which allows the sample to be heated. So far, most microwave heating equipments use 2.45 GHz; accordingly, the novelty of this study is to employ a frequency of 5.8 GHz and to investigate its effect on LTD. LTD is carried out in an autoclaved in steam at 120 ºC and 1.2 bar, because these conditions accelerate the hydrothermal aging process (3). In order to characterize the degraded samples, micro-Raman spectroscopy, AFM, nanoindentation technique and electronic microscopy have been performed.
References
1. Norton, M. R., Yarlagadda, R., Anderson, G. H. J. Bone Joint Surg. Br., 2002, 84–B, 631–635.
2. Fabbri, P., Piconi, C., Burresi, E., Magnani, G., Mazzanti, F., Mingazzini, C. Dent. Mater., 2014.
3. Presenda, Á., Salvador, M. D., Moreno, R., Borrell, A. J. Am. Ceram. Soc., 2015, 98, 3680–3689
Validez factorial del cuestionario para la evaluación del síndrome de quemarse por el trabajo (CESQT) en profesionales de servicios
Hoy en día, y desde la aparición del Inventario Maslach de Burnout (MBI), existen diversos aportes científicos alternativos de medición del burnout; sin embargo, la gran mayoría
de esos cuestionarios nacen en contextos culturales del mundo anglosajón, lo que resulta a menudo inapropiado para evaluar y comprender el desarrollo del fenómeno en contextos culturales hispanoamericanos. Por ello se desarrolló el Inventario Español de Burnout (SBI). El propósito de este trabajo fue evaluar las propiedades psicométricas del SBI. La muestra consistió en 260 trabajadores chilenos de servicios mineros. El instrumento se compone de 20 ítems distribuidos en cuatro dimensiones: Ilusión por el trabajo (5 ítems), Desgaste psíquico (4), Indolencia (6) y Culpa (5 ítems). Los datos se sometieron a análisis factorial confirmatorio para evaluar la validez factorial del SBI, donde se probaron tres modelos alternativos. Los resultados muestran que el modelo de cuatro factores tiene propiedades psicométricas adecuadas para el estudio del burnout en personal de servicios y ajustó los datos mejor que los modelos alternativos. El estudio proporciona evidencia de las propiedades
psicométricas adecuadas del SBI para evaluar burnout. El SBI propone una explicación teórica para los diferentes perfiles de burnout, facilitando el diagnóstico y el tratamiento en trabajadores de servicios
Dynamic functional connectivity in migraine during the interictal phase: a resting-state fMRI study
Question: Migraine is a cyclic and complex disorder, characterized by attacks of headache, sensory and cognitive disturbances1. Thalamocortical connectivity in migraine has been found to be transiently abnormal2. Our aim was to assess if the dynamical properties of the migraine brain are affected during the interictal phase. Methods: Resting-state functional MRI data was collected from 14 menstrual migraine patients without aura (interictal phase) and 12 healthy controls (menstrual post-ovulation phase). fMRI data processing included3: motion and distortion correction, temporal highpass filter, regression of motion and physiological confounds, spatial smoothing, and parcellation with the Desikan atlas. Dynamic functional connectivity (dFC) between regions was computed using phase coherence, and recurrent dFC states were identified by kmeans clustering (k ranging between 3 and 15) of the leading eigenvectors of dFC in each time point4. Permutation tests were performed to evaluate statistically significant differences between patients and controls in the probability of occurrence and the mean lifetime of the dFC states. Results: Similar dFC states were found consistently across different numbers of clusters, k, which resembled the canonical resting-state networks as expected. Compared to healthy controls, migraine patients show a significantly lower mean lifetime in one dFC state, when grouping in 4, 5 and 6 clusters. No differences were found for the probability of occurrence. Conclusions: Migraine may be linked to a disruption of brain networks dynamics. This emphasizes the need to adopt time-resolved methods, in addition to static, to study functional connectivity, to better understand the mechanisms of migraine. Our next step will be to assess the dynamics of the migraine brain throughout the migraine cycle.info:eu-repo/semantics/publishedVersio
Extinction law variations and dust excitation in the spiral galaxy NGC 300
We investigate the origin of the strong radial gradient in the
ultraviolet-to-infrared ratio in the spiral galaxy NGC 300, and emphasize the
importance of local variations in the interstellar medium geometry, concluding
that they cannot be neglected with respect to metallicity effects. This
analysis is based upon a combination of maps from GALEX and Spitzer, and from
the ground (UBVRI, Halpha and Hbeta). We select ionizing stellar clusters
associated with HII regions of widely varying morphologies, and derive their
fundamental parameters from population synthesis fitting of their spectral
energy distributions, measured to eliminate local backgrounds accurately. From
these fits, we conclude that the stellar extinction law is highly variable in
the line of sight of young clusters of similar ages. In the particular model
geometry that we consider most appropriate to the sampled regions, we checked
that our findings are not significantly altered by the correct treatment of
radiative transfer effects. The variations are systematic in nature: extinction
laws of the Milky Way or LMC type are associated with compact HII regions (the
compacity being quantified in two different ways), while clusters surrounded by
diffuse HII regions follow extinction laws of the 30 Doradus or SMC type. The
Calzetti starburst attenuation law, although most often degenerate with the 30
Doradus extinction law, overpredicts ionizing photon fluxes by large amounts.
We also find that the extinction law variations are correlated with the column
density of dust species emitting in the near- and mid-infrared. Finally, we
briefly discuss the nebular to stellar extinction ratios, and the excitation of
aromatic band carriers, invalidating their claimed association with cold dust.Comment: accepted for publication in ApJ -- figure 6 abridged her
Methylthioadenosine (MTA) inhibits melanoma cell proliferation and in vivo tumor growth
BACKGROUND: Melanoma is the most deadly form of skin cancer without effective treatment. Methylthioadenosine (MTA) is a naturally occurring nucleoside with differential effects on normal and transformed cells. MTA has been widely demonstrated to promote anti-proliferative and pro-apoptotic responses in different cell types. In this study we have assessed the therapeutic potential of MTA in melanoma treatment.
METHODS: To investigate the therapeutic potential of MTA we performed in vitro proliferation and viability assays using six different mouse and human melanoma cell lines wild type for RAS and BRAF or harboring different mutations in RAS pathway. We also have tested its therapeutic capabilities in vivo in a xenograft mouse melanoma model and using variety of molecular techniques and tissue culture we investigated its anti-proliferative and pro-apoptotic properties.
RESULTS: In vitro experiments showed that MTA treatment inhibited melanoma cell proliferation and viability in a dose dependent manner, where BRAF mutant melanoma cell lines appear to be more sensitive. Importantly, MTA was effective inhibiting in vivo tumor growth. The molecular analysis of tumor samples and in vitro experiments indicated that MTA induces cytostatic rather than pro-apoptotic effects inhibiting the phosphorylation of Akt and S6 ribosomal protein and inducing the down-regulation of cyclin D1.
CONCLUSIONS: MTA inhibits melanoma cell proliferation and in vivo tumor growth particularly in BRAF mutant melanoma cells. These data reveal a naturally occurring drug potentially useful for melanoma treatment
X-ray emission from the extended disks of spiral galaxies
We present a study of the X-ray properties of a sample of six nearby
late-type spiral galaxies based on XMM-Newton observations. Since our primary
focus is on the linkage between X-ray emission and star formation in extended,
extranuclear galactic disks, we have selected galaxies with near face-on aspect
and sufficient angular extent so as to be readily amenable to investigation
with the moderate spatial resolution afforded by XMM-Newton. After excluding
regions in each galaxy dominated by bright point sources, we study both the
morphology and spectral properties of the residual X-ray emission, comprised of
both diffuse emission and the integrated signal of the fainter discrete source
populations. The soft X-ray morphology generally traces the inner spiral arms
and shows a strong correlation with the distribution of UV light, indicative of
a close connection between the X-ray emission and recent star formation. The
soft (0.3-2 keV) X-ray luminosity to star formation rate (SFR) ratio varies
from 1-5 x 10^39 erg/s(/Msun/yr), with an indication that the lower range of
this ratio relates to regions of lower SFR density. The X-ray spectra are well
matched by a two-temperature thermal model with derived temperatures of
typically ~0.2 keV and ~0.65 keV, in line with published results for other
normal and star-forming galaxies. The hot component contributes a higher
fraction of the soft luminosity in the galaxies with highest X-ray/SFR ratio,
suggesting a link between plasma temperature and X-ray production efficiency.
The physical properties of the gas present in the galactic disks are consistent
with a clumpy thin-disk distribution, presumably composed of diffuse structures
such as superbubbles together with the integrated emission of unresolved
discrete sources including young supernova remnants.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Society. 17 pages, 6 figures, 7 table
The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and T e-based literature data
Astronomy and Astrophysics 559 (2013): A114 reproduced with permission from Astronomy and AstrophysicsThe use of integral field spectroscopy is since recently allowing to measure the emission line fluxes of an increasingly large number of star-forming galaxies, both locally and at high redshift. Many studies have used these fluxes to derive the gas-phase metallicity of the galaxies by applying the so-called strong-line methods. However, the metallicity indicators that these datasets use were empirically calibrated using few direct abundance data points (Te-based measurements). Furthermore, a precise determination of the prediction intervals of these indicators is commonly lacking in these calibrations. Such limitations might lead to systematic errors in determining the gas-phase metallicity, especially at high redshift, which might have a strong impact on our understanding of the chemical evolution of the Universe. The main goal of this study is to review the most widely used empirical oxygen calibrations, O3N2 and N2, by using newdirect abundance measurements. We pay special attention to (1) the expected uncertainty of these calibrations as a function of the index value or abundance derived and (2) the presence of possible systematic offsets. This is possible thanks to the analysis of the most ambitious compilation of Te-based H ii regions to date. This new dataset compiles the Te-based abundances of 603 H ii regions extracted from the literature but also includes new measurements from the CALIFA survey. Besides providing new and improved empirical calibrations for the gas abundance, we also present a comparison between our revisited calibrations with a total of 3423 additional CALIFA H ii complexes with abundances derived using the ONS calibration from the literature. The combined analysis of T e-based and ONS abundances allows us to derive their most accurate calibration to date for both the O3N2 and N2 single-ratio indicators, in terms of all statistical significance, quality, and coverage of the parameters space. In particular, we infer that these indicators show shallower abundance dependencies and statistically significant offsets compared to others'. The O3N2 and N2 indicators can be empirically applied to derive oxygen abundances calibrations from either direct abundance determinations with random errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a large amount of data), reaching an average precision of 0.08 and 0.09 dex (random) and 0.02 and 0.08 dex (systematic; compared to the direct estimations), respectivelyR.A. Marino is funded by the Spanish program of International Campus of Excellence Moncloa (CEI).
D. Mast thank the Plan Nacional de Investigación y Desarrollo funding programs, AYA2012-31935 of the Spanish Ministerio de Economía y Competitividad, for the support given to this project. S.F.S thanks the the Ramón y Cajal project RyC-2011-07590 of the spanish Ministerio de Economía y Competitividad, for the support giving to this project. F.F.R.O. acknowledges the Mexican National Council for Science and Technology
(CONACYT) for financial support under the program Estancias Postdoctorales y Sabáticas al Extranjero para la Consolidación de Grupos de Investigación, 2010-2012. We acknowledge financial support for the ESTALLIDOS collaboration by the Spanish Ministerio de Ciencia e Innovación under grant AYA2010- 21887-C04-03. BG-L also acknowledges support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AYA2012- 39408-C02-02. J.F.-B. acknowledges financial support from the Ramón y Cajal Program and grant AYA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as to the DAGAL network
from the People’s Program (Marie Curie Actions) of the European Union’s Seventh Framework Program FP7/2007-2013/ under REA grant agreement number PITN-GA-2011-289313. CK has been funded by project AYA2010-21887 from the Spanish PNAYA. P.P. acknowledges support by the Fundação para a Ciência e a Tecnologia (FCT) under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FIS-AST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE). R.M.G.D. and R.G.B. also acknowledge support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AyA2010-15081. V.S., L.G., and A.M.M. acknowledge financial support from the Fundação para a Ciência e a Tecnologia (FCT) under program Ciência 2008 and the research grant PTDC/CTE-AST/112582/200
On-chip integrated graphene aptasensor with portable readout for fast and label-free COVID-19 detection in virus transport medium
Graphene field-effect transistor (GFET) biosensors exhibit high sensitivity due to a large surface-to-volume ratio and the high sensitivity of the Fermi level to the presence of charged biomolecules near the surface. For most reported GFET biosensors, bulky external reference electrodes are used which prevent their full-scale chip integration and contribute to higher costs per test. In this study, GFET arrays with on-chip integrated liquid electrodes were employed for COVID-19 detection and functionalized with either antibody or aptamer to selectively bind the spike proteins of SARS-CoV-2. In the case of the aptamer-functionalized GFET (aptasensor, Apt-GFET), the limit-of-detection (LOD) achieved was about 103 particles per mL for virus-like particles (VLPs) in clinical transport medium, outperforming the Ab-GFET biosensor counterpart. In addition, the aptasensor achieved a LOD of 160 aM for COVID-19 neutralizing antibodies in serum. The sensors were found to be highly selective, fast (sample-to-result within minutes), and stable (low device-to-device signal variation; relative standard deviations below 0.5%). A home-built portable readout electronic unit was employed for simultaneous real-time measurements of 12 GFETs per chip. Our successful demonstration of a portable GFET biosensing platform has high potential for infectious disease detection and other health-care applications
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