2,844 research outputs found
Research on nonlinear and quantum optics at the photonics and quantum information group of the University of Valladolid
We outline the main research lines in Nonlinear and Quantum Optics of the Group of Photonics and Quantum Information at the University of Valladolid. These works focus on Optical Solitons, Quantum Information using Photonic Technologies and the development of new materials for Nonlinar Optics. The investigations on optical solitons cover both temporal solitons in dispersion managed fiber links and nonparaxial spatial solitons as described by the Nonlinear Helmholtz Equation. Within the Quantum Information research lines of the group, the studies address new photonic schemes for quantum computation and the multiplexing of quantum data. The investigations of the group are, to a large extent, based on intensive and parallel computations. Some associated numerical techniques for the development of the activities described are briefly sketched
The Representation of Queer Teen Identities in Sex Education (Netflix, 2019-)
This article provides an analysis of the representation of LGBTIQ+ teen identities in the first two seasons of ‘Sex Education’ (Netflix, 2019-). Utilising a methodology of analysis anchored in Queer Theory and in the concept of intersectionality, we will study the construction of those characters whose gender expression and/or sexual orientation defy the limits established by cisheteronormativity, as well as those whose desires (whether straight or not) do not fit within what Western societies understand as «normal», since we consider the rejection of the norm as a constitutive element of queerness. The main objectives are a.) to determine which images, knowledge and epistemological constructions regarding sexogenic diversity are disseminated by the show; and b.) to define which discourses are articulated regarding queer (non)identities and the violence suffered by LGBTIQ+ people
Evaluación de la fuerza relativa de las extremidades superiores con la plataforma de Bosco
The purpose of the study was to test whether Ergojump contact platform, used to measure the ability of lower limb drive through jumps, was valid to do it on the upper limbs from lying prone making elbow extension starting from the classical position flexion and extension of the arms and forearms at 90 degrees. A study was conducted of correlation between records of the platform (Φ= 1) and an electromyograph. Has also reliability analysis (e) experimental measure different plans that made the study variables, obtaining optimal results.El propósito del estudio fue comprobar si la Plataforma de contacto Ergojump, utilizada para medir la capacidad de impulsión de las extremidades inferiores a través de saltos, era válida para hacerlo sobre las extremidades superiores realizando desde tumbado prono una extensión de codos partiendo de la posición clásica de flexo-extensión de brazos y antebrazos de 90 grados. Se realizó un estudio de correlación entre los registros de la plataforma (Φ=1) y un electromiógrafo. También se ha realizado análisis de la fiabilidad (e) experimental de los distintos planes de medida que conformaban las distintas variables de estudio, obteniendo óptimos resultados
Distribution of melanopsin positive neurons in pigmented and albino mice: evidence for melanopsin interneurons in the mouse retina.
Here we have studied the population of intrinsically photosensitive retinal ganglion cells (ipRGCs) in adult pigmented and albino mice. Our data show that although pigmented (C57Bl/6) and albino (Swiss) mice have a similar total number of ipRGCs, their distribution is slightly different: while in pigmented mice ipRGCs are more abundant in the temporal retina, in albinos the ipRGCs are more abundant in superior retina. In both strains, ipRGCs are located in the retinal periphery, in the areas of lower Brn3a(+)RGC density. Both strains also contain displaced ipRGCs (d-ipRGCs) in the inner nuclear layer (INL) that account for 14% of total ipRGCs in pigmented mice and 5% in albinos. Tracing from both superior colliculli shows that 98% (pigmented) and 97% (albino) of the total ipRGCs, become retrogradely labeled, while double immunodetection of melanopsin and Brn3a confirms that few ipRGCs express this transcription factor in mice. Rather surprisingly, application of a retrograde tracer to the optic nerve (ON) labels all ipRGCs, except for a sub-population of the d-ipRGCs (14% in pigmented and 28% in albino, respectively) and melanopsin positive cells residing in the ciliary marginal zone (CMZ) of the retina. In the CMZ, between 20% (pigmented) and 24% (albino) of the melanopsin positive cells are unlabeled by the tracer and we suggest that this may be because they fail to send an axon into the ON. As such, this study provides the first evidence for a population of melanopsin interneurons in the mammalian retina
Probabilistic Guarded P Systems, A New Formal Modelling Framework
Multienvironment P systems constitute a general, formal
framework for modelling the dynamics of population biology, which consists
of two main approaches: stochastic and probabilistic. The framework
has been successfully used to model biologic systems at both micro (e.g.
bacteria colony) and macro (e.g. real ecosystems) levels, respectively.
In this paper, we extend the general framework in order to include
a new case study related to P. Oleracea species. The extension is made
by a new variant within the probabilistic approach, called Probabilistic
Guarded P systems (in short, PGP systems). We provide a formal definition,
a simulation algorithm to capture the dynamics, and a survey of
the associated software.Ministerio de Economía y Competitividad TIN2012- 37434Junta de Andalucía P08-TIC-0420
Depredatory impact of free-roaming dogs (Canis lupus familiaris) on Mediterranean deer in southern Spain: implications for the human-wolf conflict.
Feral dogs (Canis lupus familiaris) are efficient wild ungulate hunters in many parts of the world. This has not been confirmed in Mediterranean ecosystems. However, if feral dogs can predate upon wild Mediterranean ungulates, they can also do so upon livestock. Therefore, to more realistically understand human-wolf conflict in areas where wolves and feral dogs overlap, the possible role of the latter taking domestic prey should be considered. . During a 6-month study period, we carried out daily observations of a pack of medium-sized dogs, where they were the only large-bodied carnivore capable of killing ungulates, in a fenced estate in southern Spain. The estate contained sizeable populations of red deer, fallow deer and mouflons, but no livestock. We described feral dog predation patterns and depredatory impact. We found that dogs predated upon a total of 57 ungulates killed; fallow deer (47%) red deer (37%), and mouflon (16%). Red deer adults were the least frequent prey, but dogs killed significantly more females and fawns of red and fallow deer. Mouflons were attacked indistinctly. Our results suggest that dogs in our study exhibited a kill pattern similar to Iberian wolves. Therefore, in areas where wolves and feral dogs coexist, a significant proportion of livestock predation could be falsely attributed to the wild canid. In addition, the presence of feral dogs may be a cause of risk in big game hunting estates
Human Interaction in Learning Ecosystems based on Open Source Solutions
Technological ecosystems are software solutions based on the integration of heterogeneous software components through information flows in order to provide a set of services that each component separately does not offer, as well as to improve the user experience. In particular, the learning ecosystems are technological ecosystems focused on learning and knowledge management in different contexts such as educational institutions or companies. The ecosystem metaphor comes from biology field and it has transferred to technology field to highlight the evolving component of software. Taking into account the definitions of natural ecosystems, a technological ecosystem is a set of people and software components that play the role of organisms; a series of elements that allow the ecosystem works (hardware, networks, etc.); and a set of information flows that establish the relationships between the software components, and between these and the people involved in the ecosystem. Human factor has a main role in the definition and development of this kind of solutions. In previous works, a metamodel has been defined and validated to support Model-Driven Development of learning ecosystems based on Open Source software, but the interaction in the learning ecosystem should be defined in order to complete the proposal to improve the development process of technological ecosystems. This paper presents the definition and modelling of the human interaction in learning ecosystem
Chimeric design, synthesis, and biological assays of a new nonpeptide insulin-mimetic vanadium compound to inhibit protein tyrosine phosphatase 1B
Prior to its total synthesis, a new vanadium coordination compound, called TSAG0101,
was computationally designed to inhibit the enzyme protein tyrosine phosphatase 1B (PTP1B).
The PTP1B acts as a negative regulator of insulin signaling by blocking the active site where
phosphate hydrolysis of the insulin receptor takes place. TSAG001, [VVO2(OH)(picolinamide)],
was characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy;
IR: ν/cm−1 3,570 (NH), 1,627 (C=O, coordinated), 1,417 (C−N), 970/842 (O=V=O), 727 δ.
(pyridine ring); 13C NMR: 5 bands between 122 and 151 ppm and carbonyl C shifted to 180
ppm; and 1H NMR: 4 broad bands from 7.6 to 8.2 ppm and NH2 shifted to 8.8 ppm. In aqueous
solution, in presence or absence of sodium citrate as a biologically relevant and ubiquitous
chelator, TSAG0101 undergoes neither ligand exchange nor reduction of its central vanadium
atom during 24 hours. TSAG0101 shows blood glucose lowering effects in rats but it produced
no alteration of basal- or glucose-induced insulin secretion on β cells during in vitro tests, all
of which excludes a direct mechanism evidencing the extrapancreatic nature of its activity. The
lethal dose (LD50) of TSAG0101 was determined in Wistar mice yielding a value of 412 mg/kg.
This value is one of the highest among vanadium compounds and classifies it as a mild toxicity
agent when compared with literature data. Due to its nonsubstituted, small-sized scaffold
design, its remarkable complex stability, and low toxicity; TSAG0101 should be considered as
an innovative insulin-mimetic principle with promising properties and, therefore, could become
a new lead compound for potential nonpeptide PTP1B inhibitors in antidiabetic drug research.
In view of the present work, the inhibitory concentration (IC50) and extended solution stability
will be tested
Extraordinary absorption of sound in porous lamella-crystals
We present the design of a structured material supporting complete absorption of sound with a broadband response and functional for any direction of incident radiation. The structure which is fabricated out of porous lamellas is arranged into a low-density crystal and backed by a reflecting support. Experimental measurements show that strong all-angle sound absorption with almost zero reflectance takes place for a frequency range exceeding two octaves. We demonstrate that lowering the crystal filling fraction increases the wave interaction time and is responsible for the enhancement of intrinsic material dissipation, making the system more absorptive with less material.The work was supported by the Spanish Ministry of Science and Innovation and European Union FEDER through project FIS2011-29734-C02-01. J.C. gratefully acknowledges financial support from the Danish Council for Independent Research and a Sapere Aude grant (12-134776). V. R. G. gratefully acknowledges financial support from the ''Contratos Post-Doctorales Campus Excelencia Internacional'' UPV CEI-01-11.Christensen, J.; Romero García, V.; Picó Vila, R.; Cebrecos Ruiz, A.; Garcia De Abajo, FJ.; Mortensen, NA.; Willatzen, M.... (2014). Extraordinary absorption of sound in porous lamella-crystals. Scientific Reports. 4(4674). https://doi.org/10.1038/srep04674S44674Mei, J. et al. Dark acoustic metamaterials as super absorbers for low-frequency sound. Nat. Commun. 3, 756 (2012).Leroy, V., Strybulevych, A., Scanlon, M. G. & Page, J. Transmission of ultrasound through a single layer of bubbles. Eur. Phys. J. E 29, 123 (2009).Leroy, V., Bretagne, A., Fink, M. H. W., Tabeling, P. & Tourin, A. Design and characterization of bubble phononic crystals. Appl. Phys. Lett. 95, 171904 (2009).Thomas, E. L. Applied physics: Bubbly but quiet. Nature 462, 990 (2009).Romero-García, V., Sánchez-Pérez, J. V. & Garcia-Raffi, L. M. Tunable wideband bandstop acoustic filter based on two-dimensional multiphysical phenomena periodic systems. J. Appl. Phys. 110, 014904 (2011).Garcia-Chocano, V. M., Cabrera, S. & Sanchez-Dehesa, J. Broadband sound absorption by lattices of microperforated cylindrical shells. Appl. Phys. Lett. 101, 184101 (2012).Kushwaha, M. S., Halevi, P., Dobrzynski, L. & Djafari-Rouhani, B. Acoustic band structure of periodic elastic composites. Phys. Rev. Lett. 71, 2022 (1993).Vasseur, J. O. et al. Experimental and Theoretical Evidence for the Existence of Absolute Acoustic Band Gaps in Two-Dimensional Solid Phononic Crystals. Phys. Rev. Lett. 86, 3012 (2001).Liu, Z. et al. Locally Resonant Sonic Materials. Science 289, 1734 (2000).Christensen, J., Martin-Moreno, L. & Garcia-Vidal, F. J. All-angle blockage of sound by an acoustic double-fishnet metamaterial. Appl. Phys. Lett. 97, 134106 (2010).Botten, L. C., Craig, M. S., McPhedran, R. C., Adams, J. L. & Andrewartha, J. R. The finitely conducting lamellar diffraction grating. Optica Acta 28, 1087 (1981).McPhedran, R. C., Botten, L. C., Craif, M. S., Neviere, M. & Maystre, D. Lossy lamellar gratings in the quasistatic limit. Optica Acta 29, 289 (1982).Kravets, V. G., Schedin, F. & Grigorenko, A. N. Plasmonic blackbody: Almost complete absorption of light in nanostructured metallic coatings. Phys. Rev. B 78, 205405 (2008).Sondergaard, T. et al. Plasmonic black gold by adiabatic nanofocusing and absorption of light in ultra-sharp convex grooves. Nat. Commun. 3, 969 (2012).Clapham, P. B. & Hurtley, M. C. Reduction of Lens Reflexion by the Moth Eye Principle. Nature Vol. 244, 281 (1973).Garcia-Vidal, F. J., Pitarke, J. M. & Pendry, J. B. Effective Medium Theory of the Optical Properties of Aligned Carbon Nanotubes. Phys. Rev. Lett. 78, 4289 (1997).Yang, Z., Ci, L., Bur, J. A., Lin, S. & Ajayan, P. M. Experimental Observation of an Extremely Dark Material Made By a Low-Density Nanotube Array. Nano Lett. 8, 446 (2008).Garcia-Vidal, F. J. Metamaterials: Towards the dark side. Nat. Photonics 2, 215 (2008).Mizunoa, K. et al. A black body absorber from vertically aligned single-walled carbon nanotubes. Proc. Natl. Acad. Sci. USA 106, 6044 (2009).Lidorkis, E. & Ferrari, A. C. Photonics with Multiwall Carbon Nanotube Arrays. ACS Nano 3, 1238 (2009).Beenakker, C. W. J. & Brouwer, P. W. Distribution of the reflection eigenvalues of a weakly absorbing chaotic cavity. Physica E 9, 463 (2001).Lafarge, D., Lemarinier, P., Allard, J. F. & Tarnow, V. Dynamic compressibility of air in porous structures at audible frequencies. J. Acoust. Soc. Am. 102, 1995 (1997), With the macroscopic parameters: ϕ = 0.94, α∞ = 1, σ = 20000 Nm−4s and Λ = Λ′ = 0.41 μm.García de Abajo, F. J. Colloquium: Light scattering by particle and hole arrays. Rev. Mod. Phys. 79, 1267–1290 (2007)
The effect of beta-tricalcium phosphate on mechanical and thermal performances of poly(lactic acid)
Orthophosphates are bioactive crystals with similar structure, in terms of elemental composition and crystal nature, to human bone. In this work, biocomposite materials were prepared with poly(lactic acid) (PLA) as matrix, and betatricalcium phosphate (b-TCP) as osteoconductive filler by extrusion-compounding followed by conventional injection molding. The b-TCP load content was varied in the 10 40 wt% range and the influence of the b-TCP load on mechanical performance of PLA/b-TCP composites was evaluated. Mechanical properties of composites were obtained by standardized tensile, flexural, impact, and hardness tests. Thermal analysis of composites was carried out by means of differential scanning calorimetry; degradation at high temperatures was studied by thermogravimetric analysis; and the effect of the b-TCP load on dynamical response of composites was studied by mechanical thermal analysis in torsion mode. The bestbalanced properties were obtained for PLA composites containing 30 wt% b-TCP with a remarkable increase in the Young s modulus. These materials offer interesting properties to be used as base materials for medical applications such as interference screws due to high stiffness and mechanical resistance.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded by "Conselleria d'Educacio, Cultura i Esport" - Generalitat Valenciana ref: GV/2014/008.Ferri Azor, JM.; Gisbert, I.; García Sanoguera, D.; Reig Pérez, MJ.; Balart Gimeno, RA. (2016). The effect of beta-tricalcium phosphate on mechanical and thermal performances of poly(lactic acid). Journal of Composite Materials. 50(30):4189-4198. https://doi.org/10.1177/0021998316636205S41894198503
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