60 research outputs found
A Tool Suite to Enable Web Designers, Web Application Developers and End-users to Handle Semantic Data
Current web application development requires highly qualified staff, dealing with an extensive number of architectures and technologies. When these applications incorporate semantic data, the list of skill requirements becomes even larger, leading to a high adoption barrier for the development of semantically enabled Web applications. This paper describes VPOET, a tool focused mainly on two types of users: web designers and web application developers. By using this tool, web designers do not need specific skills in semantic web technologies to create web templates to handle semantic data. Web application developers incorporate those templates into their web applications, by means of a simple mechanism based in HTTP messages. End-users can use these templates through a Google Gadget. As web designers play a key role in the system, an experimental evaluation has been conducted, showing that VPOET provides good usability features for a representative group of web designers in a wide range of competencies in client-side technologies, ranging from amateur HTML developers to professional web designers
White dwarfs as test objects of Lorentz violations
In the present work the thermodynamical properties of bosonic and fermionic
gases are analyzed under the condition that a modified dispersion relation is
present. This last condition implies a breakdown of Lorentz symmetry. The
implications upon the condensation temperature will be studied, as well, as
upon other thermodynamical variables such as specific heat, entropy, etc.
Moreover, it will be argued that those cases entailing a violation of time
reversal symmetry of the motion equations could lead to problems with the
concept of entropy. Concerning the fermionic case it will be shown that Fermi
temperature suffers a modification due to the breakdown of Lorentz symmetry.
The results will be applied to white dwarfs and the consequences upon the
Chandrasekhar mass--radius relation will be shown. The possibility of resorting
to white dwarfs for the testing of modified dispersion relations is also
addressed. It will be shown that the comparison of the current observations
against the predictions of our model allows us to discard some values of one of
the parameters appearing in the modifications of the dispersion relation.Comment: Accepted in Classical and Quantum Gravitatio
Effective medium electrical response model of carbon nanotubes cement-based composites
The electrical properties of carbon nanotubes (CNT) cement-based composites have been modeled in previous
works by circuit models or homogenization theories. An alternative approach is the use of an effective medium
theory with induced polarization: In this work, a new model based on the generalized effective medium theory
of induced polarization (GEMTIP) with cylindrical inclusions is proposed. The presented results and discussion
show its applicability to interpret the electrical impedance spectra of cylindrical cement samples doped with
multi-walled CNTs (MWCNTs). The MWCNTs were dispersed in different media: one nonionic surfactant, two
superplasticizers, a cationic type polycarboxylate ether, and an anionic type naphthalene sulfonate. Particle
dispersion and their sizes were analyzed by Ultraviolet–Visible (UV–Vis) spectroscopy, and Scanning Electron
Microscopy (SEM) measurements. Two electrode electrical impedance spectra were measured and analyzed by
circuital models and the proposed GEMTIP model. The results demonstrate the efficiency of the proposed model
in describing the Alternating Current (AC) response of cement/CNT composites irrespective of the dispersant
agent used to elaborate the samples.CBUAConsejería de Transformación Económica, Conocimiento, Empresas Universidades de la Junta de Andalucía
P18-RT-3128MinCiencias
82779Piezoresistividad en Pasta de Cemento con Adición de Nanopartículas de Oro o Materiales CarbonososUniversidad de GranadaInstituto Colombiano de Crédito Educativo y Estudios Técnicos en el Exterio
Piezoelectric composite cements: Towards the development of self-powered and self-diagnostic materials
Piezoresistivity is the most commonly used sensing principle in cement-based smart composites for strainmonitoring applications. Nonetheless, the need for external electric power to conduct electrical resistivity
measurements restricts the scalability of this technology, especially when implemented in remote structures. To
address this issue, this manuscript thoroughly analyses the piezoelectric properties of cement composites doped
with reduced graphene oxide (rGO) and evaluates their potential as self-powered strain sensors. To do so, a
comprehensive methodology involving voltammetry measurements, open circuit potential determination, and
uniaxial compression testing is developed to determine the piezoelectric coefficients of charge �33 and voltage
�33. Furthermore, a novel circuital model for signal processing of the electromechanical response is developed
and experimentally validated in terms of time series of output voltage, resistance, and the generated electric
power. The developed methodology is applied to laboratory samples manufactured following two different
filler dispersion methods. The presented results evidence that samples prepared by ultrasonic cleaner dispersion
achieve optimal properties, with a piezoelectric charge coefficient of 1122.28 ± 246.67 pC/N, about 47 times
greater than previously reported composites in the literature. Unlike piezoresistive cement-based composites,
a remarkable nonlinear correlation between the fractional change in the intrinsic resistance of the material
and the applied mechanical strain has been observed. Instead, a considerable linearity (R
2 = 0.96) between the
externally applied mechanical strain and the generated (piezoelectric) electric power has been found, which
suggests the great potential of the latter for conducting off-the-grid strain monitoring applications
Midisuperspace Supersymmetric Quantum Cosmology
We investigate the canonical quantization in the framework of N=1 simple
supergravity for the case of a very simple gravitational midisuperspace
described by Gowdy cosmological models. We consider supersymmetric
quantum cosmology in the mentioned midisuperspace, where a matrix
representation for the gravitino covector--spinor is used. The full Lorentz
constraint and its implications for the wave function of the universe are
analyzed in detail. We found that there are indeed physical states in the
midisuperspace sector of the theory in contrast to the case of minisuperspace
where there exist no physical states.Comment: Accepted in Physical Review
In vivo cholinergic basal forebrain degeneration and cognition in Parkinson's disease: Imaging results from the COPPADIS study
COPPADIS Study Group.[Introduction] We aimed to assess associations between multimodal neuroimaging measures of cholinergic basal forebrain (CBF) integrity and cognition in Parkinson's disease (PD) without dementia.[Methods] The study included a total of 180 non-demented PD patients and 45 healthy controls, who underwent structural MRI acquisitions and standardized neurocognitive assessment through the PD-Cognitive Rating Scale (PD-CRS) within the multicentric COPPADIS-2015 study. A subset of 73 patients also had Diffusion Tensor Imaging (DTI) acquisitions. Volumetric and microstructural (mean diffusivity, MD) indices of CBF degeneration were automatically extracted using a stereotactic CBF atlas. For comparison, we also assessed multimodal indices of hippocampal degeneration. Associations between imaging measures and cognitive performance were assessed using linear models.[Results] Compared to controls, CBF volume was not significantly reduced in PD patients as a group. However, across PD patients lower CBF volume was significantly associated with lower global cognition (PD-CRStotal: r = 0.37, p < 0.001), and this association remained significant after controlling for several potential confounding variables (p = 0.004). Analysis of individual item scores showed that this association spanned executive and memory domains. No analogue cognition associations were observed for CBF MD. In covariate-controlled models, hippocampal volume was not associated with cognition in PD, but there was a significant association for hippocampal MD (p = 0.02).[Conclusions] Early cognitive deficits in PD without dementia are more closely related to structural MRI measures of CBF degeneration than hippocampal degeneration. In our multicentric imaging acquisitions, DTI-based diffusion measures in the CBF were inferior to standard volumetric assessments for capturing cognition-relevant changes in non-demented PD.This work was supported by the Alzheimer Forschung Initiative e.V. (AFI International Training Grant to MJG), the Instituto de Salud Carlos III-Fondo Europeo de Desarrollo Regional (ISCIII-FEDER) [PI14/01823, PI16/01575, PI18/01898, PI19/01576, PI20/00613], the Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía [CVI-02526, CTS-7685], the Consejería de Salud y Bienestar Social de la Junta de Andalucía [PI-0471-2013, PE-0210-2018, PI-0459-2018, PE-0186-2019], the Fundación Alicia Koplowitz and the Fundación “Curemos el Parkinson” (https://www.curemoselparkinson.org). MJG is supported by the “Miguel Servet” program [CP19/00031], MALE by the University of Seville [USE-20046-J], JFM by the “Sara Borrell” program [CD13/00229] and VI-PPIT-US from the University of Seville [USE-18817-A], SJ by the “Acción B-Clínicos-Investigadores” program [B-0007-2019], and DMG by the “Río Hortega” program [CM18/00142].Peer reviewe
Universidad y sociedad: la psicología aprendida mediante colaboraciones
Este material está dirigido tanto a investigadores como a profesores y estudiantes que tengan el interés de aprender nuevas formas de relacionarse para intervenir, en colaboración, en diferentes espacios sociales y realidades problemáticas. También puede resultar de interés para los directivos de instituciones públicas, privadas y organizaciones no gubernamentales que tengan a su cargo programas de intervención social, así como a luchadoras y luchadores sociales que busquen formas de organizarse para transformar situaciones particulares de vulnerabilidad.
En estas páginas hay una invitación a formar universitarias y universitarios a partir de su intervención en problemáticas y escenarios vivos, a reconocer el saber colectivo de los otros que están insertos en diferentes situaciones y aprender que el conocimiento se genera a partir del vínculo y la colaboración con la diversidad.ITESO. A.C
SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome
The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient’s hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome
Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection
Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2 infection induces an exacerbated inflammation driven by innate immunity components. Dendritic cells (DCs) play a key role in the defense against viral infections, for instance plasmacytoid DCs (pDCs), have the capacity to produce vast amounts of interferon-alpha (IFN-α). In COVID-19 there is a deficit in DC numbers and IFN-α production, which has been associated with disease severity. In this work, we described that in addition to the DC deficiency, several DC activation and homing markers were altered in acute COVID-19 patients, which were associated with multiple inflammatory markers. Remarkably, previously hospitalized and nonhospitalized patients remained with decreased numbers of CD1c+ myeloid DCs and pDCs seven months after SARS-CoV-2 infection. Moreover, the expression of DC markers such as CD86 and CD4 were only restored in previously nonhospitalized patients, while no restoration of integrin β7 and indoleamine 2,3-dyoxigenase (IDO) levels were observed. These findings contribute to a better understanding of the immunological sequelae of COVID-19
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