1,359 research outputs found
Pseudo-Sylvester domains and skew laurent polynomials over firs
Building on recent work of Jaikin-Zapirain, we provide a homological criterion for a ring to be a pseudo-Sylvester domain, that is, to admit a division ring of fractions over which all stably full matrices become invertible. We use the criterion to study skew Laurent polynomial rings over free ideal rings (firs). As an application of our methods, we prove that crossed products of division rings with free-by-{infinite cyclic} and surface groups are pseudo-Sylvester domains unconditionally and Sylvester domains if and only if they admit stably free cancellation. This relies on the recent proof of the Farrell--Jones conjecture for normally poly-free groups and extends previous results of Linnell--L\"uck and Jaikin-Zapirain on universal localizations and universal fields of fractions of such crossed products
Multilevel Multiphase Feedforward Space-Vector Modulation Technique
Multiphase converters have been applied to an increasing number of industrial applications in recent years. On the other hand, multilevel converters have become a mature technology mainly in medium- and high-power applications. One of the problems of multilevel converters is the dc voltage unbalance of the dc bus. Depending on the loading conditions and the number of levels of the converter, oscillations appear in the dc voltages of the dc link. This paper presents a feedforward modulation technique for multilevel multiphase converters that reduces the distortion under balanced or unbalanced dc conditions. The proposed modulation method can be applied to any multilevel-converter topology with any number of levels and phases. Experimental results are shown in order to validate the proposed feedforward modulation technique.Ministerio de Ciencia e Innovación DPI2009-07004Ministerio de Eduación y Ciencia TEC2007-6187
Reconstructing the origins and the biogeography of species’ genomes in the highly reticulate allopolyploid-rich model grass genus Brachypodium using minimum evolution, coalescence and maximum likelihood approaches
The identification of homeologous genomes and the biogeographical analyses of highly reticulate allopolyploid-rich groups face the challenge of incorrectly inferring the genomic origins and the biogeographical patterns of the polyploids from unreliable strictly bifurcating trees. Here we reconstruct a plausible evolutionary scenario of the diverging and merging genomes inherited by the diploid and allopolyploid species and cytotypes of the model grass genus Brachypodium. We have identified the ancestral Brachypodium genomes and inferred the paleogeographical ranges for potential hybridization events that originated its allopolyploid taxa. We also constructed a comprehensive phylogeny of Brachypodium from five nuclear and plastid genes using Species Tree Minimum Evolution allele grafting and Species Network analysis. The divergence ages of the lineages were estimated from a consensus maximum clade credibility tree using fossil calibrations, whereas ages of origin of the diploid and allopolyploid species were inferred from coalescence Bayesian methods. The biogeographical events of the genomes were reconstructed using a stratified Dispersal-Extinction-Colonization model with three temporal windows. Our combined Minimum Evolution-coalescence-Bayesian approach allowed us to infer the origins and the identities of the homeologous genomes of the Brachypodium allopolyploids, matching the expected ploidy levels of the hybrids. To date, the current extant progenitor genomes (species) are only known for B. hybridum. Putative ancestral homeologous genome have been inherited by B. mexicanum, ancestral and recent genomes by B. boissieri, and only recently evolved genomes by B. retusum and the core perennial clade allopolyploids (B. phoenicoides, B. pinnatum 4x, B. rupestre 4x). We dissected the complex spatio-temporal evolution of ancestral and recent genomes and have detected successive splitting, dispersal and merging events for dysploid homeologous genomes in diverse geographical scenarios that have led to the current extant taxa. Our data support Mid-Miocene splits of the Holarctic ancestral genomes that preceded the Late Miocene origins of Brachypodium ancestors of the modern diploid species. Successive divergences of the annual B. stacei and B. distachyon diploid genomes were implied to have occurred in the Mediterranean region during the Late Miocene-Pliocene. By contrast, a profusion of splits, range expansions and different genome mergings were inferred for the perennial diploid genomes in the Mediterranean and Eurasian regions, with sporadic colonizations and further mergings in other continents during the Quaternary. A reliable biogeographical scenario was obtained for the Brachypodium genomes and allopolyploids where homeologous genomes split from their respective diploid counterpart lineages in the same ancestral areas, showing similar or distinct dispersals. By contrast, the allopolyploid taxa remained in the same ancestral ranges after hybridization and genome doubling events. Our approach should have utility in deciphering the genomic composition and the historical biogeography of other allopolyploid-rich organismal groups, which are predominant in eukaryotes
Caveolin-1 Modulates Mechanotransduction Responses to Substrate Stiffness through Actin-Dependent Control of YAP
The transcriptional regulator YAP orchestrates many cellular functions, including tissue homeostasis, organ growth control, and tumorigenesis. Mechanical stimuli are a key input to YAP activity, but the mechanisms controlling this regulation remain largely uncharacterized. We show that CAV1 positively modulates the YAP mechanoresponse to substrate stiffness through actin-cytoskeleton-dependent and Hippo-kinase-independent mechanisms. RHO activity is necessary, but not sufficient, for CAV1-dependent mechanoregulation of YAP activity. Systematic quantitative interactomic studies and image-based small interfering RNA (siRNA) screens provide evidence that this actin-dependent regulation is determined by YAP interaction with the 14-3-3 protein YWHAH. Constitutive YAP activation rescued phenotypes associated with CAV1 loss, including defective extracellular matrix (ECM) remodeling. CAV1-mediated control of YAP activity was validated in vivo in a model of pancreatitis-driven acinar-to-ductal metaplasia. We propose that this CAV1-YAP mechanotransduction system controls a significant share of cell programs linked to these two pivotal regulators, with potentially broad physiological and pathological implications. Moreno-Vicente et al. report that CAV1, a key component of PM mechanosensing caveolae, mediates adaptation to ECM rigidity by modulating YAP activity through the control of actin dynamics and phosphorylation-dependent interaction of YAP with the 14-3-3-domain protein YWHAH. Cav1-dependent YAP regulation drives two pathophysiological processes: ECM remodeling and pancreatic ADM. © 2018 The Author
A comparison of robust Kalman filtering methods for artifact correction in heart rate variability analysis
La variabilidad de la frecuencia cardiaca (HRV) ha recibido una atención considerable por mucho años, ya que esta proporciona un valor cuantitativo para examinar el ritmo sinusal modulado para el sistema nervioso autónomo (SNA). El SNA juega un papel importante en campos clínicos y fisiológicos. El análisis de la HRV se puede realizar calculando varias medidas tanto en el domino del tiempo como en la frecuencia. Sin embargo, el cálculo de estas medidas se puede ver afectado por la presencia de artefactos o latidos ectópicos en registros de electrocardiogramas (ECG). Esto es particularmente cierto para registros ECG desde un monitor Holter. El objetivo de este trabajo fue estudiar el rendimiento de varios filtros de Kalman robustos para la corrección de artefactos. Para nuestros experimentos, se usaron dos bases de datos reales: el primer conjunto de datos incluye 10 series de tiempo de intervalos RR a partir de un generador de series de tiempo de intervalos RR realista. La segunda base de datos contiene 10 conjuntos de series de intervalos RR de cinco pacientes sanos y cinco pacientes que sufren una insuficiencia cardiaca congestiva. Se calculó la desviación estándar de los intervalos RR a partir de las señales filtradas. Los resultados se compararon con un reconocido software de procesamiento, mostrando comportamientos y valores similares. Adicionalmente, los métodos propuestos ofrecen resultados satisfactorios en comparación con el filtro de Kalman estándar.Heart rate variability (HRV) has received considerable attention for many years, since it provides a quantitative marker for examining the sinus rhythm modulated by the autonomic nervous system (ANS). The ANS plays an important role in clinical and physiological fields. HRV analysis can be performed by computing several time and frequency domain measurements. However, the computation of such measurements can be affected by the presence of artifacts or ectopic beats in the electrocardiogram (ECG) recording. This is particularly true for ECG recordings from Holter monitors. The aim of this work was to study the performance of several robust Kalman filters for artifact correction in Inter-beat (RR) interval time series. For our experiments, two data sets were used: the first data set included 10 RR interval time series from a realistic RR interval time series generator. The second database contains 10 sets of RR interval series from five healthy patients and five patients suffering from congestive heart failure. The standard deviation of the RR interval was computed over the filtered signals. Results were compared with a state of the art processing software, showing similar values and behavior. In addition, the proposed methods offer satisfactory results in contrast to standard Kalman filtering
Effectiveness of Guided Breathing and Social Support for the Reduction of Pre-Exam Anxiety in University Students: A Factorial Study
Anxiety is a state of mind that university students often manifest in exam situations, which
can negatively impact their grades. This study aimed to evaluate the effect of different relaxation
techniques, including guided breathing and social support, on test anxiety among nursing students
a few minutes before taking the final knowledge assessment test. For this purpose, a factorial
study with a post-intervention measurement was carried out with three groups of nursing students.
One group used the full yogic breathing relaxation technique (abdominal, thoracic, and clavicular),
another used a social support technique, and the last group did not receive any intervention. Of
119 participants, 98.2% showed a moderate-high level of anxiety. Regarding the anxiety scale score, it
was found that participants with moderate anxiety levels had higher scores on the knowledge test
(Rho = 0.222; p = 0.015). The present study found no differences in anxiety levels between the study
groups. Combining these relaxation techniques with others shown to be effective could reinforce
their positive effect. Starting to work on this anxiety from the beginning of nursing courses appears
to be a good strategy, striving to improve students’ confidence in their abilities
Winograd technique. About one case
Una de las técnicas quirúrgicas de elección para las onicocriptosis severas es el Winograd. En el presente artículo presentamos el caso de un varón de 17 años, afecto de onicocriptosis severa, con los rodetes ungueales hipertróficos al que sometimos a cirugía ungueal con resultados satisfactorios tanto para él como para los profesionales que llevamos a cabo la intervención.One of the surgical techniques of election for the severe onicocriptosis is the Winograd. In the present article we presents the clinical case of a man of 17 years old, affected of severe onicocriptosis, with the nails fols hypertrophied who underwent to nail surgery with satisfactory results for him as for the professionals as much who we carried out the intervention
Testing the goodness of fit of a hilbertian autoregressive model
The presented methodology for testing the goodness-of-fit of an
Autoregressive Hilbertian model (ARH(1) model) provides an infinite-dimensional
formulation of the approach proposed in Koul and Stute (1999), based on
empirical process marked by residuals. Applying a central and functional
central limit result for Hilbert-valued martingale difference sequences, the
asymptotic behavior of the formulated H-valued empirical process, also indexed
by H, is obtained under the null hypothesis. The limiting process is H-valued
generalized (i.e., indexed by H) Wiener process, leading to an asymptotically
distribution free test. Consistency is also analyzed. The case of misspecified
autocorrelation operator of the ARH(1) process is addressed as well. Beyond the
Euclidean setting, this approach allows to implement goodness of fit testing in
the context of manifold and spherical functional autoregressive processes
Calidad de la Tithonia diversifolia en una zona del Valle del Cauto
13 páginas, 5 tablas.This experiment was carried out with the objective of determining the nutritive value of Tithonia diversifolia to different bud ages during the two periods of the year. A 0.5 ha field was used, where a standardization cut at 15 cm high from the soil was applied at the beginning of each period. The ages taken into consideration were 60, 120 and 180 days, and the elements evaluated were the RP, the fibrous fractioning, the dry matter In vitro digestibility, the wall cell digestibility and the tanins. To this purpose, a random- block design with three treatments and four repetitions was used through the application of a double classification analysis, and the average results were compared by means of the multiple ranges Duncan test. The statistical program utilized was Statiics version 6.0 for Windows. In the chapter that deals with the analysis of the results, it is evident that the dry matter, NDF, ADF, ADL, Hemicellulous, TF, TCT, CTAF and FTC increased their content (29. 47 %, 50. 51 %, 32. 12 %, 32. 12 %, 18. 39 %, 6.47, 13. 11, 10. 12, and 2. 99 g/kg respectively) at the age of 180 days, whereas the raw protein, the cellulous, the cell content, the In vitro digestibility and the wall cell digestibility decreased with their highest value (28.95, 21.08, 56.34, 78.59 y 76.61 %) at the age of 60 days. As a conclusion, age had a marked effect on the behavior of the evaluated elements, which was stronger during the rainy season, decreasing the nutritive quality.Trabajo realizado con financiación del Programa de Cooperación Interuniversitaria e Investigación Científica de la Agencia Española de Cooperación Internacional para el Desarrollo (Proyecto AECID A/023167/09).Peer Reviewe
Secondary poisoning of non-target animals in an Ornithological Zoo in Galicia (NW Spain) with anticoagulant rodenticides: a case report
The use of anticoagulants has increased in recent times as a method for controlling rodent populations. However, this increased use also provokes accidental and intentional ingestion for both animals and humans,
triggering poisoning of non-target organisms. In the present report, a clinical case of secondary-poisoning of
birds with anticoagulant rodenticides, which took place after a general rodenticide treatment in an Ornithological
Zoological Park, is described. Three birds died as a result and samples were submitted to the Veterinary Hospital
in Lugo (Galicia, NW Spain). After necropsy, samples of the birds, together with molluscs and faeces, were submitted to the Toxicology Unit of Caceres (Extremadura, W Spain) in order to detect possible chemicals. Results
from HPLC analyses revealed the presence of the rodenticides difenacoum and brodifacoum. The present report
shows that the risk of secondary exposure resulting from the scavenging of molluscs is likely to be significant.
The potential routes of uptake by invertebrates include the consumption of rodent faeces, rodent carcases, the
ingestion of soil-bound residues, and the direct consumption of poison baits.Irene de la Casa-Resino was supported by fellowship PRE09001 from Department of Employment,
Enterprise and Innovation (Gobierno de Extremadura, Spain)S
- …