Principal Channel Research Articles

Spin Transport and Dynamics in Multilayer Magnetic Nanostructures

The interconnection between the spin current and spin dynamics via the spin-dependent scattering and an accompanying by spin torque effect in ferromagnetic/normal metal based magnetic multilayer nanostructures is studied including a high fast out-of-equilibrium spin dynamics. Features of the spin transport through interfaces and its impact on spin dynamics are described on the base of the scattering matrix formalism for spin flows. The dependence of the spin torque effect on conductance character of the normal metal layers is considered. The exchange processes between the itinerant <i>s</i> and the localized <i>d</i> electrons are described by kinetic rate equations for electron-magnon spin-flop scattering. It is shown that the magnon distribution function remains nonthermalized on the relevant time scales of the demagnetization process, and the relaxation of the out-of-equilibrium spin accumulation among itinerant electrons provides the principal channel for dissipation of spin angular momentum from the combined electronic system.

Analysis of queuing mine-cars affecting shaft station radon concentrations in Quzhou uranium mine, eastern China

Abstract Shaft stations of underground uranium mines in China are not only utilized as waiting space for loaded mine-cars queuing to be hoisted but also as the principal channel for fresh air taken to working places. Therefore, assessment of how mine-car queuing processes affect shaft station radon concentration was carried out. Queuing network of mine-cars has been analyzed in an underground uranium mine, located in Quzhou, Zhejiang province of Eastern China. On the basis of mathematical analysis of the queue network, a MATLAB-based quasi-random number generating program utilizing Monte-Carlo methods was worked out. Extensive simulations were then implemented via MATALB operating on a DELL PC. Thereafter, theoretical calculations and field measurements of shaft station radon concentrations for several working conditions were performed. The queuing performance measures of interest, like average queuing length and waiting time, were found to be significantly affected by the utilization rate (positively correlated). However, even with respect to the “worst case”, the shaft station radon concentration was always lower than 200 Bq/m3. The model predictions were compared with the measuring results, and a satisfactory agreement was noted. Under current working conditions, queuing-induced variations of shaft station radon concentration of the study mine are not remarkable.

La homogenización de contenidos en el duopolio privado de televisión en España: Atresmedia y Mediaset

El artículo presenta un análisis comparativo entre las dos plataformas privadas de televisión más importantes de España. Se ofrece un análisis de contenido de los cuatro canales de mayor audiencia de Atresmedia y Mediaset (canales generalistas y temáticos) para demostrar empíricamente que ambos grupos mediáticos tienen una estrategia programática muy similar que acucia, más si cabe, la falta de pluralismo en el panorama mediático español. Se concluye, a través de la presentación de gráficos comparativos entre las cadenas homólogas, que se dan significativas coincidencias en la tipología y estrategia programática de ambas plataformas.

Numerical investigation on natural convection in horizontal channel partially filled with aluminium foam and heated from above

Natural convection gets a great attention for its importance in many thermal engineering applications, such as cooling of electronic components and devices, chemical vapor deposition systems and solar energy systems. In this work, a numerical investigation on steady state natural convection in a horizontal channel partially filled with a porous medium and heated at uniform heat flux from above is carried out. A three-dimensional model is realized and solved by means of the ANSYS-FLUENT code. The computational domain is made up of the principal channel and two lateral extended reservoirs at the open vertical sections. Furthermore, a porous plate is considered near the upper heated plate and the aluminium foam has different values of PPI. The numerical simulations are performed with working fluid air. Different values of assigned wall heat flux at top surface are considered and the configuration of the channel partially filled with metal foam is compared to the configuration without foam. Results are presented in terms of velocity and temperature fields, and both temperature and velocity profiles at different significant sections are shown. Results show that the use of metal foams, with low values of PPI, promotes the cooling of the heated wall and it causes a reduction of Nusselt Number values with high values of PPI.

Planform characteristics and development of interchannel wetlands in a gravel-bed anastomosing river, Maqu Reach of the Upper Yellow River

Both interchannel wetlands and multi-channels are crucial geomorphologic units in an anastomosing river system. Planform characteristics and development of interchannel wetlands and multi-channels control the characteristics of anastomosing rivers. To understand the role that interchannel wetlands play in the development of anastomosing rivers, a study was conducted on the Maqu Reach of the Upper Yellow River (MRUYR), a gravel-bed anastomosing river characterized by highly developed interchannel wetlands and anabranches. Geomorphologic units in the studied reach were extracted from high resolution satellite imagery in Google Earth. The size distributions of interchannel wetlands and interchannel wetland clusters (IWCs), a special combination of interchannel wetlands and anabranches, were investigated. Geomorphologic parameters, including the ratio of interchannel wetland area to IWC area (P), shoreline density (Dl), and node density (Dn) were used to analyze planform characteristics of IWCs and the development of multi-channels in the studied reach. The results suggest that small or middle sized interchannel wetlands and large or mega sized IWCs are more common at the study site. The area of IWC (Su) is highly correlated with other geomorphologic parameters. P increases with increasing Su, and the upper limit is about 80%, which indicates that the development of interchannel wetlands and anabranches in the IWC is in the equilibrium stage. In contrast, Dl and Dn show a tendency to decrease with increasing Su due to diverse evolution processes in IWCs with different sizes. There are three main reasons leading to the formation of IWCs: varying stream power due to the meandering principal channel; development of the river corridor due to the weakening of geologic structure control; and high stability of interchannel wetlands due to conservation by shoreline vegetation.

Deriving principal channel metrics from bank and long-profile geometry with the R package cmgo

Abstract. Landscape patterns result from landscape forming processes. This link can be exploited in geomorphological research by reversely analyzing the geometrical content of landscapes to develop or confirm theories of the underlying processes. Since rivers represent a dominant control on landscape formation, there is a particular interest in examining channel metrics in a quantitative and objective manner. For example, river cross-section geometry is required to model local flow hydraulics, which in turn determine erosion and thus channel dynamics. Similarly, channel geometry is crucial for engineering purposes, water resource management, and ecological restoration efforts. These applications require a framework to capture and derive the data. In this paper we present an open-source software tool that performs the calculation of several channel metrics (length, slope, width, bank retreat, knickpoints, etc.) in an objective and reproducible way based on principal bank geometry that can be measured in the field or in a GIS. Furthermore, the software provides a framework to integrate spatial features, for example the abundance of species or the occurrence of knickpoints. The program is available at https://github.com/AntoniusGolly/cmgo and is free to use, modify, and redistribute under the terms of the GNU General Public License version 3 as published by the Free Software Foundation.

Sociology in Paraguay

Sociology has been taught in Paraguay since 1900. In those years, it was included in the training of other humanities, such as law. Despite this early appearance, the education of sociology is now only 30 years old and exhibits an evolutionary lethargy. The discipline was institutionalized not because it was taught as a major course of study, but because of the publication of two national journals that have existed for more than four decades: Revista Paraguaya de Sociología (Paraguayan Journal of Sociology) and Estudios Paraguayos (Paraguayan Studies). These were the means through which the first sociological articles appeared and currently remain principal channels of knowledge in the field. The objective of this essay is to describe national sociological academic production by analyzing the last five issues of both publications. The classification of topics, methodologies, approaches, use of bibliographies, and types of articles was carried out using hand-coded qualitative text analysis.

A genetic variant of the sperm-specific SLO3 K+ channel has altered pH and Ca2+ sensitivities

To fertilize an oocyte, sperm must first undergo capacitation in which the sperm plasma membrane becomes hyperpolarized via activation of potassium (K+) channels and resultant K+ efflux. Sperm-specific SLO3 K+ channels are responsible for these membrane potential changes critical for fertilization in mouse sperm, and they are only sensitive to pH i However, in human sperm, the major K+ conductance is both Ca2+- and pH i -sensitive. It has been debated whether Ca2+-sensitive SLO1 channels substitute for human SLO3 (hSLO3) in human sperm or whether human SLO3 channels have acquired Ca2+ sensitivity. Here we show that hSLO3 is rapidly evolving and reveal a natural structural variant with enhanced apparent Ca2+ and pH sensitivities. This variant allele (C382R) alters an amino acid side chain at a principal interface between the intramembrane-gated pore and the cytoplasmic gating ring of the channel. Because the gating ring contains sensors to intracellular factors such as pH and Ca2+, the effectiveness of transduction between the gating ring and the pore domain appears to be enhanced. Our results suggest that sperm-specific genes can evolve rapidly and that natural genetic variation may have led to a SLO3 variant that differs from wild type in both pH and intracellular Ca2+ sensitivities. Whether this physiological variation confers differences in fertility among males remains to be established.

Distinct roles of light-activated channels TRP and TRPL in photoreceptors of Periplaneta americana.

Electrophysiological studies in Drosophila melanogaster and Periplaneta americana have found that the receptor current in their microvillar photoreceptors is generated by two light-activated cationic channels, TRP (transient receptor potential) and TRPL (TRP-like), each having distinct properties. However, the relative contribution of the two channel types to sensory information coding by photoreceptors remains unclear. We recently showed that, in contrast to the diurnal Drosophila in which TRP is the principal phototransduction channel, photoreceptors of the nocturnal P. americana strongly depend on TRPL. Here, we perform a functional analysis, using patch-clamp and intracellular recordings, of P. americana photoreceptors after RNA interference to knock down TRP (TRPkd) and TRPL (TRPLkd). Several functional properties were changed in both knockdown phenotypes: cell membrane capacitance was reduced 1.7-fold, light sensitivity was greatly reduced, and amplitudes of sustained light-induced currents and voltage responses decreased more than twofold over the entire range of light intensities. The information rate (IR) was tested using a Gaussian white-noise modulated light stimulus and was lower in TRPkd photoreceptors (28 ± 21 bits/s) than in controls (52 ± 13 bits/s) because of high levels of bump noise. In contrast, although signal amplitudes were smaller than in controls, the mean IR of TRPLkd photoreceptors was unchanged at 54 ± 29 bits/s1 because of proportionally lower noise. We conclude that TRPL channels provide high-gain/high-noise transduction, suitable for vision in dim light, whereas transduction by TRP channels is relatively low-gain/low-noise and allows better information transfer in bright light.

Transmission Mechanism of Monetary Policy in Nigeria

This paper, explored the empirical importance of credit. It adds to the existing literature in two ways. First, it analyses in a systematic way both endogenous and exogenous instruments of monetary mechanism using information on the country’s main economic objectives as a proxy for bank credit availability by providing a framework in which to analyse the evidence in controlling money and credit. Second, by using bank’s prices (rather than quantities) it provides an alternative way to disentangle loan supply from loan demand shift in the ‘credit channel’ literature. The paper also provides empirical evidence on the role of banks in the monetary transmission process. The principal channel appears through lending to firms, which influences entire economy investment. The existence of an effective banking industry is necessary for every economy because it create the necessary environment for economic growth and development through its role in intermediating funds from surplus to deficit economic units. This stimulates investment economic growth, and employment as well as international trade and payment. The bottom line is that credit is an important part of the transmission process of Nigerian Monetary Policy.

The sorting receptor Rer1 controls Purkinje cell function via voltage gated sodium channels

Rer1 is a sorting receptor in the early secretory pathway that controls the assembly and the cell surface transport of selected multimeric membrane protein complexes. Mice with a Purkinje cell (PC) specific deletion of Rer1 showed normal polarization and differentiation of PCs and normal development of the cerebellum. However, PC-specific loss of Rer1 led to age-dependent motor deficits in beam walk, ladder climbing and gait. Analysis of brain sections revealed a specific degeneration of PCs in the anterior cerebellar lobe in old animals. Electrophysiological recordings demonstrated severe deficits in spontaneous action potential generation. Measurements of resurgent currents indicated decreased surface densities of voltage-gated sodium channels (Nav), but not changes in individual channels. Analysis of mice with a whole brain Rer1-deletion demonstrated a strong down-regulation of Nav1.6 and 1.1 in the absence of Rer1, whereas protein levels of the related Cav2.1 and of Kv3.3 and 7.2 channels were not affected. The data suggest that Rer1 controls the assembly and transport of Nav1.1 and 1.6, the principal sodium channels responsible for recurrent firing, in PCs.

International Migration and Institutional Quality in the Home Country: It Matters Where You Go and How Long You Stay!

International migrants are widely recognised as agents of institutional change in their home countries. However, the huge growth in temporary migration in recent years demands a fresh investigation of this phenomenon. Theoretically, a country's diaspora constitutes one of the four principal channels through which international migration may alter development. A core factor enabling the transnational influence of diasporas is their retained connection to home countries, which is plausibly contingent on the duration-of-stay in the host countries. This paper exploits the Database on Immigrants in OECD Countries to investigate the influence of diasporas living in OECD countries on institutional quality in their home countries, and takes into account the heterogeneity of diasporas' duration-of-stay composition. Instead of simply using immigrant numbers to measure the diaspora size, we calculate institutional-quality-adjusted immigrant stocks to allow for variations in institutional quality between host countries. Additionally, we utilize duration-of-stay in the host country as an indicator of the strength of interaction with the home country. Our cross-sectional and panel analyses find a significant positive impact of diasporas living in OECD countries on institutional quality in home countries. Remarkably, the diffusion of advanced institutions from developed host countries to home countries through the international migration channel is stronger with diasporas characterized by shorter duration-of-stay, i.e. with those who may be expected to still have stronger links with the home country.

Cartoons vs. Manga Movies: A Brief History of Anime in the UK

This paper has as main objective to explore, adopting a historical and critical perspective, the release of film and anime TV in UK. This would be a first step towards the studio of the peculiar implementation of manganime Culture in Britain. Compared with other European countries, UK has shown to be slower and even reluctant in importing Japanese television products. Thus, while major markets of anime such as France, Italy or Spain expanded considerably during 1975-1995 period, in a recurrent synergy of television markets, and technological publishing, the implantation of the principal channel (televised anime) in UK has been irregular and unstable. Even today, the catalogue of broadcasting anime is limited to some high success movies, late night television on thematic channels and quite recently, video-on-demand services (Netflix). The offer cannot be compare in importance and diversity to other European countries. This fact, far from being anecdotal, has had an impact on the subsequent implantation of media Japanese cultures such as manga, anime, video games and cosplay. What can be the reason of this irregular development of Japanese visual culture in United Kingdom? Characteristic having the television market and / or the UK audience? Main hypothesis in relation to these issues can be considered to be of sociological character, but are reflected in the idiosyncrasies of British television culture and production system. Thus, compared to other Western markets (including the US) which saw the opportunity to purchase economic products for children’s television audiences in the late 70s and early 80s, the British ‘telly’ already offered a broad catalogue (Roobarb, Super Ted, Danger Mouse, etc. ...). The only exception to this children’s ‘made in Britain’ programming was the co-production model. This caused a leak of few products that were not even considered as “Japanese” (Seven Cities of Gold, Godzilla) but mere ‘cartoons’. This competition with the British children production as well as the wide catalogue of other forms of British Popular Culture would explain why the film, domestic video and later adults programming would be the marginal routes of entry for manganime.

Información televisiva y movilidad. Análisis de las noticias más seguidas a través de twitter

Social networks such as Facebook and Twitter, and mobile applications such as Periscope, Snapchat, Whatsapp, among others, are some of the emerging ways of communication and access to information in recent times, for both general users and professionals of the information. Technological advances and innovations derived mainly from the web 2.0 have added new screens to traditional media, so that the newspaper can not only be read, but now also can be seen and heard, while television, besides been seen and heard, also read. To this, mobility and portability is added, as demanded by users today, and in which the mobile screen has a prominent role and influence, especially because of social networks. This contribution describes which is the production and consumption of news that comes from the information provided by the principal generalist television channels in Spain through the most mobile social network, Twitter.

Biallelic Loss of Proprioception-Related PIEZO2 Causes Muscular Atrophy with Perinatal Respiratory Distress, Arthrogryposis, and Scoliosis

We report ten individuals of four independent consanguineous families from Turkey, India, Libya, and Pakistan with a variable clinical phenotype that comprises arthrogryposis, spontaneously resolving respiratory insufficiency at birth, muscular atrophy predominantly of the distal lower limbs, scoliosis, and mild distal sensory involvement. Using whole-exome sequencing, SNPchip-based linkage analysis, DNA microarray, and Sanger sequencing, we identified three independent homozygous frameshift mutations and a homozygous deletion of two exons in PIEZO2 that segregated in all affected individuals of the respective family. The mutations are localized in the N-terminal and central region of the gene, leading to nonsense-mediated transcript decay and consequently to lack of PIEZO2 protein. In contrast, heterozygous gain-of-function missense mutations, mainly localized at the C terminus, cause dominant distal arthrogryposis 3 (DA3), distal arthrogryposis 5 (DA5), or Marden-Walker syndrome (MWKS), which encompass contractures of hands and feet, scoliosis, ophthalmoplegia, and ptosis. PIEZO2 encodes a mechanosensitive ion channel that plays a major role in light-touch mechanosensation and has recently been identified as the principal mechanotransduction channel for proprioception. Mice ubiquitously depleted of PIEZO2 are postnatally lethal. However, individuals lacking PIEZO2 develop a not life-threatening, slowly progressive disorder, which is likely due to loss of PIEZO2 protein in afferent neurons leading to disturbed proprioception causing aberrant muscle development and function. Here we report a recessively inherited PIEZO2-related disease and demonstrate that depending on the type of mutation and the mode of inheritance, PIEZO2 causes clinically distinguishable phenotypes.

Efficacy and Safety of Rituximab Therapy in Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSDs) are autoimmune astrocytopathies characterized by predominant involvement of the optic nerves and spinal cord. In most patients, an IgG autoantibody binding to astrocytic aquaporin 4, the principal water channel of the central nervous system, is detected. Rituximab, a chimeric monoclonal antibody specific for the CD20 B-lymphocyte surface antigen, has been increasingly adopted as a first-line off-label treatment for patients with NMOSDs. To perform a systematic review and a meta-analysis of the efficacy and safety of rituximab use in NMOSDs, considering the potential predictive factors related to patient response to rituximab in this disease. English-language studies published between January 1, 2000, and July 31, 2015, were searched in the MEDLINE, Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov databases. Patient characteristics, outcome measures, treatment regimens, and recorded adverse effects were extracted. Forty-six studies were included in the systematic review. Twenty-five studies that included 2 or more patients with NMOSDs treated with rituximab were included in the meta-analysis. Differences in the annualized relapse rate ratio and Expanded Disability Status Scale score before and after rituximab therapy were the main efficacy measures. Safety outcomes included the proportion of deaths, withdrawals because of toxic effects, and adverse effects. Among 46 studies involving 438 patients (381 female and 56 male [sex was not specified in 1 patient]; mean age at the outset of treatment, 32 years [age range, 2-77 years]), rituximab therapy resulted in a mean (SE) 0.79 (0.15) (95% CI, -1.08 to -0.49) reduction in the mean annualized relapse rate ratio and a mean (SE) 0.64 (0.27) (95% CI, -1.18 to -0.10) reduction in the mean Expanded Disability Status Scale score. A significant correlation was observed between disease duration and the Expanded Disability Status Scale score. Adverse effects were recorded in 114 of 438 (26%) patients treated with rituximab. Specifically, 45 patients (10.3%) experienced infusion-related adverse effects, 40 patients (9.1%) had an infection, 20 patients (4.6%) developed persistent leukopenia, 2 patients (0.5%) were diagnosed as having posterior reversible encephalopathy, and 7 patients (1.6%) died. This systematic review and meta-analysis provides evidence that rituximab therapy reduces the frequency of NMOSD relapses and neurological disability in patients with NMOSDs. However, the safety profile suggests caution in prescribing rituximab as a first-line therapy.

Loss of the proprioception and touch sensation channel PIEZO2 in siblings with a progressive form of contractures.

Dominant mutations in PIEZO2, which codes for the principal mechanotransduction channel for proprioception and touch sensation, have been found to cause different forms of distal arthrogryposis. Some observations suggest that these dominant mutations induce a gain-of-function effect on the channel. Here, we report a consanguineous family with three siblings who showed short stature, scoliosis, gross motor impairment, and a progressive form of contractures involving the distal joints that is distinct from that found in patients with dominant mutations in PIEZO2. These siblings also displayed deficits in proprioception and touch sensation. Whole-exome sequencing performed in the three affected siblings revealed the presence of a rare homozygous variant (c.2708C>G; p.S903*) in PIEZO2. This variant is predicted to disrupt PIEZO2 function by abolishing the pore domain. Sanger sequencing confirmed that all three siblings are homozygous whereas their parents and an unaffected sibling are heterozygous for this variant. Recessive mutations in PIEZO2 thus appear to cause a progressive phenotype that overlaps with, while being mostly distinct from that associated with dominant mutations in the same gene.

Ichnology and depositional environment of the Middle Devonian Valentia Island tetrapod trackways, south-west Ireland

Nine tetrapod trackways are described from the Middle Devonian continental Valentia Slate Formation on the north-eastern coast of Valentia Island in County Kerry, Ireland. The trackways occur at three sites – Dohilla, Coosadillisk and Culoo Head – the latter two being recorded for the first time. Morphological and taphonomic analyses of the trackways suggest they were made by populations of similar tetrapods, but of varying size (body length=0.5 to 1m; width=0.15 to 0.30m), that moved in some cases by terrestrial locomotion and in others possibly by a slow “paddling gait” while the substrate was submerged by very shallow floodwater. Sedimentological facies analysis of the trackway-bearing sequences has been carried out for the first time and shows that the preserved trackways are associated with the late stages of (1) a principal river channel margin (Coosadillisk), (2) a minor floodplain drainage channel (Culoo Head) and (3) a sand-rich crevasse splay/medial alluvial-ridge environment (Dohilla). The Valentia Island tetrapods inhabited marginal environments of proximal river channels <20km from the northern margin of the Munster Basin, where hinterland drainage basins probably provided reliable sources of water in an overall semi-arid climate. It is proposed that the more perennial river channel belts crossing the basin would have provided conducive route ways that allowed ancestral tetrapods to migrate (>170km) northwards into the continent from postulated shallow marine habitats as they evolved this capability over a potential 4–5 million year period during the Middle Devonian.

Classification in emotional BCI using phase information from the EEG.

Synchronization and distributed functional networks have been used with success in different areas of engineering. In this paper we use the synchronization information from electroencephalogram (EEG) channels through the Phase Locking Value (PLV) as a potential classification method for a Brain Computer Interface (BCI); this achieved using emotional schematic faces as stimuli in a motor imagery (MI) task. Based on the variations of the PLV values for each proposed task and for each participant, the principal channel pairs are identified. Selected channel pairs, corresponding with the accomplished task, present PLV patterns similarly to Evoked Potentials (ERS/ERD) which are widely used as classification features for MI based BCI.

Modulation of Ionic Channels and Insulin Secretion by Drugs and Hormones in Pancreatic Beta Cells

Pancreatic beta cells, unique cells that secrete insulin in response to an increase in glucose levels, play a significant role in glucose homeostasis. Glucose-stimulated insulin secretion (GSIS) in pancreatic beta cells has been extensively explored. In this mechanism, glucose enters the cells and subsequently the metabolic cycle. During this process, the ATP/ADP ratio increases, leading to ATP-sensitive potassium (KATP) channel closure, which initiates depolarization that is also dependent on the activity of TRP nonselective ion channels. Depolarization leads to the opening of voltage-gated Na(+) channels (Nav) and subsequently voltage-dependent Ca(2+) channels (Cav). The increase in intracellular Ca(2+) triggers the exocytosis of insulin-containing vesicles. Thus, electrical activity of pancreatic beta cells plays a central role in GSIS. Moreover, many growth factors, incretins, neurotransmitters, and hormones can modulate GSIS, and the channels that participate in GSIS are highly regulated. In this review, we focus on the principal ionic channels (KATP, Nav, and Cav channels) involved in GSIS and how classic and new proteins, hormones, and drugs regulate it. Moreover, we also discuss advances on how metabolic disorders such as metabolic syndrome and diabetes mellitus change channel activity leading to changes in insulin secretion.