Derivation of the physical parameters of the jet in S5 0836+710 from stability analysis

A number of extragalactic jets show periodic structures at different scales that can be associated with growing instabilities. The wavelengths of the developing instability modes and their ratios depend on the flow parameters, so the study of those structures can shed light on jet physics at the scales involved. In this work, we use the fits to the jet ridgeline obtained from different observations of S5 B0836$+$710 and apply stability analysis of relativistic, sheared flows to derive an estimate of the physical parameters of the jet. Based on the assumption that the observed structures are generated by growing Kelvin-Helmholtz (KH) instability modes, we have run numerical calculations of stability of a relativistic, sheared jet over a range of different jet parameters. We have spanned several orders of magnitude in jet-to-ambient medium density ratio, and jet internal energy, and checked different values of the Lorentz factor and shear layer width. This represents an independent method to obtain estimates of the physical parameters of a jet. By comparing the fastest growing wavelengths of each relevant mode given by the calculations with the observed wavelengths reported in the literature, we have derived independent estimates of the jet Lorentz factor, specific internal energy, jet-to-ambient medium density ratio and Mach number. We obtain a jet Lorentz factor $\gamma \simeq 12$, specific internal energy of $\varepsilon \simeq 10^{-2}\,c^2$, jet-to-ambient medium density ratio of $\eta\approx 10^{-3}$, and an internal (classical) jet Mach number of $M_\mathrm{j}\approx 12$. We also find that the wavelength ratios are better recovered by a transversal structure with a width of $\simeq 10\,\%$ of the jet radius. This method represents a powerful tool to derive the jet parameters in all jets showing helical patterns with different wavelengths.Comment: Accepted for publication in A&A, 15 pages, 12 figure

Spin-dependent electronic conduction along zigzag graphene nanoribbons bearing adsorbed Ni and Fe nanostructures

Using SMEAGOL, an ab initio computational method that combines the non-equilibrium Green's function formalism with density-functional theory, we calculated spin-specific electronic conduction in systems consisting of single Fen and Nin nanostructures (n = 1−4) adsorbed on a hydrogen-passivated zigzag graphene nanoribbon. For each cluster we considered both ferromagnetically and antiferromagnetically coupled ribbon edges (Ferro-F and Ferro-A systems, respectively). Adstructures located laterally on Ferro-A ribbons caused significant transmittance loss at energies 0.6–0.25 eV below the Fermi level for one spin and 0.2–0.4 eV above the Fermi level for the other, allowing the potential use of these systems in transistors to create a moderately spin-polarized current of one or the other sign depending on the gate voltage. Ni₃ and Ni₄ clusters located at the centre of Ferro-F ribbons exhibited a strong spin-filtering effect in a narrow energy window around the Fermi level

Spin currents and filtering behavior in zigzag graphene nanoribbons with adsorbed molybdenum chains

By means of density-functional-theoretic calculations, we investigated the structural, electronic and transport properties of hydrogen-passivated zigzag graphene nanoribbons (ZGNRs) on which a one-atom-thick Mo chain was adsorbed (with or without one or two missing atoms), or in which the passivating hydrogen atoms were replaced by Mo atoms. Mo-passivated ZGNRs proved to be nonmagnetic. ZGNRs with an adsorbed defect-free Mo chain were most stable with the Mo atoms forming dimers above edge bay sites, which suppressed the magnetic moments of the C atoms in that half of the ribbon; around the Fermi level of these systems, each spin component had a transmission channel via the Mo spz band and one had an additional channel created by polarization of the ZGNR π* band, leading to a net spin current. The absence of an Mo dimer from an Mo chain adsorbed at the ZGNR edge made the system a perfect spin filter at low voltage bias by suppressing the Mo spz band channels. Thus this last kind of hybrid system is a potential spin valve

Influence of chronological age in the selection of players into the national basketball teams

[EN] The Relative Age Effect (RAE) is "the difference in age and maturity, among people who have been grouped under the same age, for a specific purpose or function" (Lorenzo and Calleja, 2010). The aim of this study is to analyse the presence of the effect in the Spanish National Basketball Teams from U-16 category to the senior teams (n = 110), who competed over summer 2013. The study will address the possible relationship to gender and playing position. This analysis will show the variations in the percentage of births throughout the year calendar. A descriptive study set whose variables include month of birth, gender (male or female), category (U16, U18, U19, U20, Senior) and playing position (inside or outside player). Significant differences in the distribution of births grouped by periods (p = .46 χ2 (4) = 9.6) were found. In men’s youth teams there is a significant difference in the number of players who are selected from the first and second semester depending on whether they are inside or outside players (χ2 (1) = 5.42; p = .20, V = .34). Likewise, in women’s youth teams there is also a significant difference (χ2 (1) = 9.24; p = .002, V = .49). In conclusion, the effect is present through the Spanish basketball teams, especially at non-senior levels. It begins at the first competitive age and disappears into the senior teams. Furthermore, youth categories are specifically affected according to the position of play. It seems necessary to revise the models of organizing competitions trying to achieve other more balanced and less exclusive. Also rethinking selection and detection of talent methods of male and female players in the Spanish basketball.S

Spontaneous Symmetry Breakdown in non-relativistic Quantum Mechanics

The advantages and disadvantages of some pedagogical non-relativistic quantum-mechanical models, used to illustrate spontaneous symmetry breakdown, are discussed. A simple quantum-mechanical toy model (a spinor on the line, subject to a magnetostatic interaction) is presented, that exhibits the spontaneous breakdown of an internal symmetry.Comment: 19 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1111.1213. Equations (30) and (31) have been corrected. Other minor correction

Frontotemporal dementia-associated N279K tau mutation localizes at the nuclear compartment

Tau is a microtubule-associated protein that plays an important role in Alzheimer’s disease and related tauopathies. Approximately one-half of all cases of Frontotemporal dementia with parkinsonism-17 (FTDP-17) are caused by mutations in the MAPT gene. The N279K mutation is one of the three mutations more prevalent in FTDP-17 cases. Several studies have demonstrated that N279K Tau mutation alters alternative splicing inducing the presence of exon 10. Tau is mainly found in the cytosol of neuronal cells although it has also been localized within the nucleus. Here we demonstrate by biochemical and immunohistochemistry studies in COS-7 cells, that the proportion of mutant N279K Tau increases compared with wild-type at the cell nucleus although cell viability is not affected. These data will provide us with a better outline of the nuclear role of tau protein offering new clues related with this tauopathie.This study was funded by grants from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía y Competitividad; SAF-2014-53040-P (JA) and BFU2016-77885- P (FH)), the Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII; JA)

Ultrathin carbon nanotube with single, double, and triple bonds

A metastable carbon nanotube with single, double, and triple bonds has been predicted from abinitio simulation. It results from the relaxation of an ideal carbon nanotube with chirality (2,1), without any potential barrier between the ideal nanotube and the new structure. Ten-membered carbon rings are formed by breaking carbon bonds between adjacent hexagons; eight-membered rings, already present in the ideal structure, become the smallest rings. This structure is stable in molecular dynamics simulations at temperatures up to 1000K. Raman, infrared, and optical absorption spectra are simulated to allow its identification in the laboratory. The structure can be described as a double helical chain with alternating single, double, and triple bonds, where the chains are bridged by single bondsThis work was supported by Grants No. SB2010-0119 (MEC), No. CTQ2010-19232 (MICIN), and No. A1/035856/11 (AECID

The Cutaneous Biopsy for the Diagnosis of Peripheral Neuropathies: Meissner’s Corpuscles and Merkel’s Cells

Cutaneous biopsy is a complementary method, alternative to peripheral nerve biopsy, for the analysis of nerve involvement in peripheral neuropathies, systemic diseases, and several pathologies of the central nervous system. Most of these neuropathological studies were focused on the intraepithelial nerve fibers (thin-myelinated Aδ fibers and unmyelinated C fibers), and few studies investigated the variations in dermal innervation, that is, large myelinated fibers, Merkel’s cell-neurite complexes, and Meissner’s corpuscles. Here, we updated and summarized the current data about the quantitative and qualitative changes that undergo MCs and MkCs in peripheral neuropathies. Moreover, we provide a comprehensive rationale to include MCs in the study of cutaneous biopsies when analyzing the peripheral neuropathies and aim to provide a protocol to study them

Diffusion on a solid surface: Anomalous is normal

We present a numerical study of classical particles diffusing on a solid surface. The particles' motion is modeled by an underdamped Langevin equation with ordinary thermal noise. The particle-surface interaction is described by a periodic or a random two dimensional potential. The model leads to a rich variety of different transport regimes, some of which correspond to anomalous diffusion such as has recently been observed in experiments and Monte Carlo simulations. We show that this anomalous behavior is controlled by the friction coefficient, and stress that it emerges naturally in a system described by ordinary canonical Maxwell-Boltzmann statistics

Rumen fermentation and diet degradability in sheep fed sugarcane (Saccharum officinarum) silage supplemented with Tithonia diversifolia or alfalfa (Medicago sativa) and rice polishing

The objective of this study was to evaluate ruminal fermentation (i.e. pH, ammonia, and volatile fatty acid concentrations) and in situ degradability of diets in sheep fed sugarcane silage (SCS) supplemented with Tithonia diversifolia (Td) or alfalfa (Medicago sativa) hay (A), with or without rice (Oriza sativa) polishing (RP) as an energy source. Four Blackbelly sheep (35 kg average body weight) with rumen cannula were used. The experimental diets were (g/kg of dry matter): Diet 1) SCS (686) + Td (294), Diet 2) SCS (460) + Td (226) + RP (294), Diet 3) SCS (637) + A (343), and Diet 4) SCS (441) + A (245) + RP (294). The remainder (20 g/kg of dry matter) was composed by minerals supplement and salt. Samples of diets were incubated into rumen for 3, 6, 9, 12, 24, 30, 36, 48, and 72 h to determine in situ degradability. Data were analysed with a linear mixed model. The lamb, period and lamb nested in period*diet were considered as a random variable. The inclusion of RP improved the degradability of diets and ammonia production in the rumen. The acetic, propionic, and butyric acid concentrations (mmol/100 mL) in rumen increased (P<0.03) when diets with alfalfa and RP were provided. The degradability of diets based on sugarcane silage supplemented with either alfalfa or Tithonia diversifolia was improved (P<0.05) with the rice polishing inclusion, with no difference (P>0.05) between these forages. In conclusion, energy supplementation, not necessarily from starch, is important to improve rumen fermentation and degradability of diets based on sugarcane silage