1,374 research outputs found
Forage production and quality of common vetch mixtures with barley, oat and triticale in four phenological stages
Para determinar la producción y la calidad del forraje de la mezcla de veza común con cebada, avena, y triticale en dos proporciones de semilla (65:35; 35:65) durante cuatro etapas fenológicas, se estableció un experimento en un diseño de bloques completos al azar con arreglo factorial (3x4x4) con cuatro repeticiones. En mezclas de cultivos la mayor producción de materia seca (MS) la obtuvo la asociación avena-veza con 16.6 t ha-1 y en proporción de cultivos la avena-veza (65:35) produjo 19.9 t ha-1, durante la etapa grano masoso (P<0.001). La mayor cantidad de proteína cruda la obtuvieron las mezclas avena-veza (178 g kg-1 MS) y triticale-veza (161 g kg-1 MS) durante la etapa de embuche. Los menores valores de fibra detergente neutra los presentaron el monocultivo veza y su mezcla con avena (35:65), durante la etapa grano maduro (P<0.001). Las menores cantidades de fibra detergente ácida lo obtuvieron los monocultivos avena, veza y triticale durante la etapa grano lechoso (P<0.001). El mayor porcentaje de nutrientes digestibles totales lo obtuvo el monocultivo veza y su mezcla con cebada (65:35) durante la etapa grano lechoso, respectivamente (P<0.001). El contenido de energía neta de lactación y el valor relativo de forraje fue mayor para el monocultivo veza (P<0.001). Se concluye que la producción y calidad del forraje en mezcla de veza con cereales (cebada, avena y triticale) dependen de la etapa de cosecha. En este estudio, la mezcla avena-veza logró mayor producción de materia seca y mejor contenido de proteína cruda. Además, el valor relativo del forraje fue más alto durante la etapa grano maduro.The objective was to determine forage yield and quality of vetch mixtures with barley, oat and triticale in two seeding ratios (65:35; 35:65) at four phenological stages. To this end, a randomized block design with factorial array (3x4x4) and four replications was established. The greatest dry matter yield was obtained from the oat-vetch mixture at the grain doughy stage of maturity (16.6 t ha-1; P<0.00), while the seed proportion with the highest production was from the oat-vetch (65:35) ratio with 19.9 t ha-1 during the dough grain stage. The highest amount of crude protein was obtained from the oat-vetch (178 g kg-1 MS) and triticale-vetch (161 g kg-1 MS) mixtures during booting stage. The monoculture vetch and oats-vetch (35:65) proportion, both had lower amounts of neutral detergent fiber at the mature grain stage (P<0.001). The oat, vetch and triticale monocultures showed the lowest acid detergent fiber during milky grain stage (P<0.001). The greatest percentage of TDN was observed in vetch monoculture and its mixtures with barley (65:35) during the milky grain stage, respectively (P<0.001). The monoculture vetch provided highest values for NEL and RFV (P<0.001). In conclusion, the forage yield and quality of vetch mixtures with barley, oat and triticale depend on the maturity stage. Also, the oat-vetch mixture showed the greatest dry matter yield and high CP concentration. In addition, forage relative value was higher during the mature grain stage
Enhancing the stability of the synchronization of multivariable coupled oscillators
Synchronization processes in populations of identical networked oscillators are the focus of intense studies in physical, biological, technological, and social systems. Here we analyze the stability of the synchronization of a network of oscillators coupled through different variables. Under the assumption of an equal topology of connections for all variables, the master stability function formalism allows assessing and quantifying the stability properties of the synchronization manifold when the coupling is transferred from one variable to another. We report on the existence of an optimal coupling transference that maximizes the stability of the synchronous state in a network of Rössler-like oscillators. Finally, we design an experimental implementation (using nonlinear electronic circuits) which grounds the robustness of the theoretical predictions against parameter mismatches, as well as against intrinsic noise of the system.Support from Spanish Ministry of Economy and Competitiveness through Projects No. FIS2011-25167, No. FIS2012-38266, and No. FIS2013-41057-P is also acknowledged. A.A. and J.G.G. acknowledge supportfrom the EC FET-Proactive Projects PLEXMATH (GrantNo. 317614) and MULTIPLEX (Grant No. 317532). J.G.G. acknowledges support from MINECO through the Ramón y Cajal program, the Comunidad de Aragón (Grupo FENOL), and the Brazilian CNPq through the PVE project of the Ciencia Sem Fronteiras program. A.A. acknowledges ICREA Academia and the James S. McDonnell Foundation. R.S.E. ac-knowledges Universidad de Guadalajara, CULagos (Mexico) for financial support (OP/PIFI-2013-14MSU0010Z-17-04,PROINPEP-RG/005/2014, UDG-CONACyT/I010/163/2014) and CONACyT (Becas Mixtas MZO2015/290842)
Experimental implementation of maximally synchronizable networks
Maximally synchronizable networks (MSNs) are acyclic directed networks that maximize synchronizability. In this paper, we investigate the feasibility of transforming networks of coupled oscillators into their corresponding MSNs. By tuning the weights of any given network so as to reach the lowest possible eigenratio lambdaN/lambda2, the synchronized state is guaranteed to be maintained across the longest possible range of coupling strengths. We check the robustness of the resulting MSNs with an experimental implementation of a network of nonlinear electronic oscillators and study the propagation of the synchronization errors through the network. Importantly, a method to study the effects of topological uncertainties on the synchronizability is proposed and explored both theoretically and experimentally.The authors acknowledge J.L. Echenausía-Monroy, V.P. Vera-Ávila, J. Moreno de León, C. Hapo and P.L. del Barrio for assistance in the laboratory, and the support of MINECO (FIS2012-38949-C03-01 and FIS2013-41057-P). One anonymous referee is acknowledged for having provided valuable advice that has influenced our understanding of the origin of the propagation of the synchronization error, and helped us improve the manuscript in several ways. The authors also acknowledge the computational resources, facilities and assistance provided by the Centro computazionale di RicErca sui Sistemi COmplessi (CRESCO) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). R.S.E. acknowledges Universidad de Guadalajara, CULagos (Mexico) for financial support (PRO-SNI-2015/228069, PROINPEP/005/2014, UDG-CONACyT/I010/163/2014) and CONACyT (Becas Mixtas MZO2015/290842). D.-U. Hwang acknowledges National Institute for Mathematical Sciences (NIMS) funded by the Ministry of Science, ICT & Future Planning (A21501-3)
Analytical Solution for Electrical Problem Forced by a Finite-Length Needle Electrode: Implications in Electrostimulation
[EN] Needle electrodes, widely used in clinical procedures, are responsible for creating an electric field in the treated biological tissue. This is achieved by setting a constant voltage along the length of their metallic section. In accordance with Laplace's equation, the electric field is spatially non-uniform around the electrode surface. Mathematical modelling can provide useful information on the spatial distribution of electrical fields. Indeed, exact solutions for the electrical problem are indispensable for validating numerical codes. All the analytical models developed to date to solve the needle electrode electrical problem have been one-dimensional models, which assumed an electrode of infinite length. We here propose the first analytical solution based on a two-dimensional model that considers the real length of the electrode in which the Laplace equation is solved through the method of separation of variables, dealing with the nonhomogeneous source term and boundary conditions by Green's functions. On assuming a needle electrode of given length, the problem combines boundary conditions on the electrode boundary (of the first and second kind). Since this rules out using the Sturm-Liouville Theorem, the problem is decomposed into two different problems and the principle of superposition is used. The solution obtained can reproduce a reasonable electric field around the electrode, especially the edge effect characterized by an extremely high gradient around the electrode tip.This work was supported by the Universidad Autonoma de San Luis Potosi (Mexico), which granted R. Romero-Mendez who is on a sabbatical leave to do research in the field of biomedical engineering. This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades under "Programa Estatal de I+D+i Orientada a los Retos de la Sociedad" (grant number: RTI2018-094357-B-C21).Romero-Méndez, R.; Pérez-Gutiérrez, FG.; Oviedo-Tolentino, F.; Berjano, E. (2019). Analytical Solution for Electrical Problem Forced by a Finite-Length Needle Electrode: Implications in Electrostimulation. Mathematical Problems in Engineering. 1-10. https://doi.org/10.1155/2019/2404818S110Mulier, S., Miao, Y., Mulier, P., Dupas, B., Pereira, P., de Baere, T., … Ni, Y. (2005). Electrodes and multiple electrode systems for radiofrequency ablation: a proposal for updated terminology. European Radiology, 15(4), 798-808. doi:10.1007/s00330-004-2584-xMerrill, D. R., Bikson, M., & Jefferys, J. G. R. (2005). Electrical stimulation of excitable tissue: design of efficacious and safe protocols. Journal of Neuroscience Methods, 141(2), 171-198. doi:10.1016/j.jneumeth.2004.10.020Cogan, S. F. (2008). Neural Stimulation and Recording Electrodes. Annual Review of Biomedical Engineering, 10(1), 275-309. doi:10.1146/annurev.bioeng.10.061807.160518Kwon, H., Rutkove, S. B., & Sanchez, B. (2017). Recording characteristics of electrical impedance myography needle electrodes. Physiological Measurement, 38(9), 1748-1765. doi:10.1088/1361-6579/aa80acBurdío, F., Berjano, E. J., Navarro, A., Burdío, J. M., Güemes, A., Grande, L., … de Gregorio, M. A. (2007). RF tumor ablation with internally cooled electrodes and saline infusion: what is the optimal location of the saline infusion? BioMedical Engineering OnLine, 6(1), 30. doi:10.1186/1475-925x-6-30Zhang, B., Moser, M. A. J., Zhang, E. M., Luo, Y., Liu, C., & Zhang, W. (2016). A review of radiofrequency ablation: Large target tissue necrosis and mathematical modelling. Physica Medica, 32(8), 961-971. doi:10.1016/j.ejmp.2016.07.092Samoudi, A. M., Kampusch, S., Tanghe, E., Széles, J. C., Martens, L., Kaniusas, E., & Joseph, W. (2017). Numerical modeling of percutaneous auricular vagus nerve stimulation: a realistic 3D model to evaluate sensitivity of neural activation to electrode position. Medical & Biological Engineering & Computing, 55(10), 1763-1772. doi:10.1007/s11517-017-1629-7Samoudi, A. M., Vermeeren, G., Tanghe, E., Van Holen, R., Martens, L., & Josephs, W. (2016). Numerically simulated exposure of children and adults to pulsed gradient fields in MRI. Journal of Magnetic Resonance Imaging, 44(5), 1360-1367. doi:10.1002/jmri.25257Trujillo, M., Bon, J., José Rivera, M., Burdío, F., & Berjano, E. (2016). Computer modelling of an impedance-controlled pulsing protocol for RF tumour ablation with a cooled electrode. International Journal of Hyperthermia, 32(8), 931-939. doi:10.1080/02656736.2016.1190868Ewertowska, E., Mercadal, B., Muñoz, V., Ivorra, A., Trujillo, M., & Berjano, E. (2017). Effect of applied voltage, duration and repetition frequency of RF pulses for pain relief on temperature spikes and electrical field: a computer modelling study. International Journal of Hyperthermia, 34(1), 112-121. doi:10.1080/02656736.2017.1323122Zhang, B., Moser, M. A. J., Zhang, E. M., Luo, Y., & Zhang, W. (2016). A new approach to feedback control of radiofrequency ablation systems for large coagulation zones. International Journal of Hyperthermia, 33(4), 367-377. doi:10.1080/02656736.2016.1263365Haemmerich, D., Chachati, L., Wright, A. S., Mahvi, D. M., Lee, F. T., & Webster, J. G. (2003). Hepatic radiofrequency ablation with internally cooled probes: effect of coolant temperature on lesion size. IEEE Transactions on Biomedical Engineering, 50(4), 493-500. doi:10.1109/tbme.2003.809488López Molina, J. A., Rivera, M. J., & Berjano, E. (2017). Analytical transient-time solution for temperature in non perfused tissue during radiofrequency ablation. Applied Mathematical Modelling, 42, 618-635. doi:10.1016/j.apm.2016.10.044Romero-Méndez, R., & Berjano, E. (2017). An Analytical Solution for Radiofrequency Ablation with a Cooled Cylindrical Electrode. Mathematical Problems in Engineering, 2017, 1-12. doi:10.1155/2017/9021616Verhey, J., Nathan, N., Rienhoff, O., Kikinis, R., Rakebrandt, F., & D’Ambra, M. (2006). BioMedical Engineering OnLine, 5(1), 17. doi:10.1186/1475-925x-5-1
Obstáculos y retos para el desarrollo de sistemas de información en el sector salud.
Objective. The purpose of Information Systems in Health (SIS) is to improve the health of individuals and populations through the appropriate application of knowledge generated by the organization of information in such systems. Materials and methods. A literature review was conducted through the experiences and results obtained in the development and implementation of an SIS. Results. The analysis of the requirements is the starting point for the development or acquisition of any software product. The SIS must consider the inclusion of the necessary data for the investigation and allow for its organization depending on the type of inquiry that will be carried out. It must simplify and accelerate access to critical information while controlling access to data, facilitate the statistical processing of large amounts of data, and finally facilitate the exchange of data between different systems. Conclusions. The set of obstacles and challenges for the development of the SIS listed in this article confirms the high complexity of this type of information systems for which mature and detailed planning is needed.Objetivo. El propósito de los Sistemas de Información en de la Salud (SIS) es mejorar la salud de los individuos y las poblaciones mediante la aplicación apropiada del conocimiento generado por la organización de la información en dichos sistemas. Materiales y métodos. Se realizó una revisión sistemática de literatura a través de las experiencias y lineamientos en el desarrollo y la implementación de un SIS. Resultados. El análisis de los requisitos es el punto de partida para el desarrollo o la adquisición de cualquier producto de software. El SIS debe contemplar la inclusión de los datos necesarios para la investigación y permitir su organización dependiendo del tipo de investigación que se quiera realizar; debe simplificar y acelerar el acceso a la información crítica al mismo tiempo que controla el acceso a los datos; debe facilitar el tratamiento estadístico de grandes cantidades de datos; y, finalmente, debe facilitar el intercambio de datos entre diversos sistemas. Conclusiones. El conjunto de los obstáculos y retos para el desarrollo de los SIS enumerados en este artículo confirma la gran complejidad que presenta este tipo de sistemas de información, para ello se requiere de una planeación madura y detallada.
 
Evolution of naturally occurring 5'non-coding region variants of Hepatitis C virus in human populations of the South American region
<p>Abstract</p> <p>Background</p> <p>Hepatitis C virus (HCV) has been the subject of intense research and clinical investigation as its major role in human disease has emerged. Previous and recent studies have suggested a diversification of type 1 HCV in the South American region. The degree of genetic variation among HCV strains circulating in Bolivia and Colombia is currently unknown. In order to get insight into these matters, we performed a phylogenetic analysis of HCV 5' non-coding region (5'NCR) sequences from strains isolated in Bolivia, Colombia and Uruguay, as well as available comparable sequences of HCV strains isolated in South America.</p> <p>Methods</p> <p>Phylogenetic tree analysis was performed using the neighbor-joining method under a matrix of genetic distances established under the Kimura-two parameter model. Signature pattern analysis, which identifies particular sites in nucleic acid alignments of variable sequences that are distinctly representative relative to a background set, was performed using the method of Korber & Myers, as implemented in the VESPA program. Prediction of RNA secondary structures was done by the method of Zuker & Turner, as implemented in the <it>mfold </it>program.</p> <p>Results</p> <p>Phylogenetic tree analysis of HCV strains isolated in the South American region revealed the presence of a distinct genetic lineage inside genotype 1. Signature pattern analysis revealed that the presence of this lineage is consistent with the presence of a sequence signature in the 5'NCR of HCV strains isolated in South America. Comparisons of these results with the ones found for Europe or North America revealed that this sequence signature is characteristic of the South American region.</p> <p>Conclusion</p> <p>Phylogentic analysis revealed the presence of a sequence signature in the 5'NCR of type 1 HCV strains isolated in South America. This signature is frequent enough in type 1 HCV populations circulating South America to be detected in a phylogenetic tree analysis as a distinct type 1 sub-population. The coexistence of distinct type 1 HCV subpopulations is consistent with quasispecies dynamics, and suggests that multiple coexisting subpopulations may allow the virus to adapt to its human host populations.</p
TMEM95 is a sperm membrane protein essential for mammalian fertilization.
The fusion of gamete membranes during fertilization is an essential process for sexual reproduction. Despite its importance, only three proteins are known to be indispensable for sperm-egg membrane fusion: the sperm proteins IZUMO1 and SPACA6, and the egg protein JUNO. Here we demonstrate that another sperm protein, TMEM95, is necessary for sperm-egg interaction. TMEM95 ablation in mice caused complete male-specific infertility. Sperm lacking this protein were morphologically normal exhibited normal motility, and could penetrate the zona pellucida and bind to the oolemma. However, once bound to the oolemma, TMEM95-deficient sperm were unable to fuse with the egg membrane or penetrate into the ooplasm, and fertilization could only be achieved by mechanical injection of one sperm into the ooplasm, thereby bypassing membrane fusion. These data demonstrate that TMEM95 is essential for mammalian fertilization. © 2020, Lamas-Toranzo et al
A Multiple-Choice Maze-like Spatial Navigation Task for Humans Implemented in a Real-Space, Multipurpose Circular Arena
Spatial navigation is a key aspect of human behavior and it is still not completely understood. A number of experimental approaches exist, although most of the published data in the last decades have relied on virtual maze on-screen simulation or not-completely freely moving 3D devices. Some interesting recent developments, such as circular mazes, have contributed to analyze critical aspects of freely moving human spatial navigation in real space, although dedicated protocols only allow for simple approaches. Here, we have developed both specifically designed and home-assembled hardware equipment, and a customized protocol for spatial navigation evaluation in freely moving humans in a real space circular arena. The spatial navigation protocol poses an imitation of a real-space multiple-choice path maze with cul-de-sac and instances of non-linear movement. We have compared the results of this system to those of a number of validated, both virtual and real, spatial navigation tests in a group of participants. The system composed by hardware, the test protocol, and dedicated measure analysis designed in our laboratory allows us to evaluate human spatial navigation in a complex maze with a small and portable structure, yielding a highly flexible, adaptable, and versatile access to information about the subjects’ spatial navigation abilities
Searching for non-Gaussianity in the VSA data
We have tested Very Small Array (VSA) observations of three regions of sky
for the presence of non-Gaussianity, using high-order cumulants, Minkowski
functionals, a wavelet-based test and a Bayesian joint power
spectrum/non-Gaussianity analysis. We find the data from two regions to be
consistent with Gaussianity. In the third region, we obtain a 96.7% detection
of non-Gaussianity using the wavelet test. We perform simulations to
characterise the tests, and conclude that this is consistent with expected
residual point source contamination. There is therefore no evidence that this
detection is of cosmological origin. Our simulations show that the tests would
be sensitive to any residual point sources above the data's source subtraction
level of 20 mJy. The tests are also sensitive to cosmic string networks at an
rms fluctuation level of (i.e. equivalent to the best-fit observed
value). They are not sensitive to string-induced fluctuations if an equal rms
of Gaussian CDM fluctuations is added, thereby reducing the fluctuations due to
the strings network to rms . We especially highlight the usefulness
of non-Gaussianity testing in eliminating systematic effects from our data.Comment: Minor corrections; accepted for publication to MNRA
- …