Spin-current modulation and square-wave transmission through periodically stubbed electron waveguides

Ballistic spin transport through waveguides, with symmetric or asymmetric double stubs attached to them periodically, is studied systematically in the presence of a weak spin-orbit coupling that makes the electrons precess. By an appropriate choice of the waveguide length and of the stub parameters injected spin-polarized electrons can be blocked completely and the transmission shows a periodic and nearly square-type behavior, with values 1 and 0, with wide gaps when only one mode is allowed to propagate in the waveguide. A similar behavior is possible for a certain range of the stub parameters even when two-modes can propagate in the waveguide and the conductance is doubled. Such a structure is a good candidate for establishing a realistic spin transistor. A further modulation of the spin current can be achieved by inserting defects in a finite-number stub superlattice. Finite-temperature effects on the spin conductance are also considered.Comment: 19 pages, 8 figure

Clusters of galaxies: setting the stage

Clusters of galaxies are self-gravitating systems of mass ~10^14-10^15 Msun. They consist of dark matter (~80 %), hot diffuse intracluster plasma (< 20 %) and a small fraction of stars, dust, and cold gas, mostly locked in galaxies. In most clusters, scaling relations between their properties testify that the cluster components are in approximate dynamical equilibrium within the cluster gravitational potential well. However, spatially inhomogeneous thermal and non-thermal emission of the intracluster medium (ICM), observed in some clusters in the X-ray and radio bands, and the kinematic and morphological segregation of galaxies are a signature of non-gravitational processes, ongoing cluster merging and interactions. In the current bottom-up scenario for the formation of cosmic structure, clusters are the most massive nodes of the filamentary large-scale structure of the cosmic web and form by anisotropic and episodic accretion of mass. In this model of the universe dominated by cold dark matter, at the present time most baryons are expected to be in a diffuse component rather than in stars and galaxies; moreover, ~50 % of this diffuse component has temperature ~0.01-1 keV and permeates the filamentary distribution of the dark matter. The temperature of this Warm-Hot Intergalactic Medium (WHIM) increases with the local density and its search in the outer regions of clusters and lower density regions has been the quest of much recent observational effort. Over the last thirty years, an impressive coherent picture of the formation and evolution of cosmic structures has emerged from the intense interplay between observations, theory and numerical experiments. Future efforts will continue to test whether this picture keeps being valid, needs corrections or suffers dramatic failures in its predictive power.Comment: 20 pages, 8 figures, accepted for publication in Space Science Reviews, special issue "Clusters of galaxies: beyond the thermal view", Editor J.S. Kaastra, Chapter 2; work done by an international team at the International Space Science Institute (ISSI), Bern, organised by J.S. Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke

Kingroup and origin of the cultivar \u2018Sangiovese\u2019 revealed

L\u2019obiettivo del presente studio \ue8 l\u2019identificazione delle parentele e della storia genetica del \u2018Sangiovese\u2019, nonch\ue9 della sua origine. L\u2019analisi di strutturazione genetica in popolazioni e di parentela \ue8 stata realizzata utilizzando una grande banca dati (2786 profili genetici unici di 20 nSSR), con una particolare attenzione rivolta alle cultivar toscane. Tra le cultivar analizzate, \ue8 stata identificata una popolazione genetica \u201citalica\u201d composta da antiche cultivar tradizionalmente coltivate in Italia, che include anche il \u2018Sangiovese\u2019. Dieci cultivar compongono la \u201cfamiglia\u201d del \u2018Sangiovese\u2019, che possiede due discendenti diretti: cv \u2018Ciliegiolo\u2019 e cv \u2018Catarratto bianco faux\u2019. Contrariamente alla sua diffusa e storica presenza nell\u2019area tirrenica. il \u2018Sangiovese\u2019 possiede numerose parentele con cultivar coltivate nel Sud Italia, soprattutto in Sicilia e Calabria

Circulating T-cell Immunosenescence in Patients with Advanced Non-small Cell Lung Cancer Treated with Single-agent PD-1/PD-L1 Inhibitors or Platinum-based Chemotherapy

Purpose: CD28, CD57, and KLRG1 have been previously identified as markers of T-cell immunosenescence. The impact of immunosenescence on anti-PD(L)-1 (ICI) or platinum-based chemotherapy (PCT) in patients with advanced non-small cell lung cancer (aNSCLC) is unknown.Experimental Design: The percentage of CD28(-), CD57(+), KLRG1(+) among CD8(+) T cells [senescent immune phenotype (SIP)] was assessed by flow cytometry on blood from patients with aNSCLC before single-agent ICI (discovery cohort). A SIP cutoff was identified by log-rank maximization method and patients with aNSCLC treated with ICI (validation cohort) or PCT were classified accordingly. Proliferation and functional properties of SIP+ CD8(+) T cells were assessed in vitro.Results: In the ICI discovery cohort (N = 37), SIP cut-off was 39.5%, 27% of patients were SIP+. In the ICI validation cohort (N = 46), SIP+ status was found in 28% of patients and significantly correlated with worse objective response rate (ORR; 0% vs. 30%, P = 0.04), median progression-free survival (PFS) [1.8 (95% confidence interval (CI), 1.3-NR) vs. 6.4 (95% CI, 2-19) months, P = 0.009] and median overall survival, OS [2.8 (95% CI, 2.0-NR) vs. 20.8 (95% CI, 6.0-NR) months, P = 0.02]. SIP+ status was significantly associated with circulating specific immunephenotypes, in vitro lower CD8(+) T cells proliferation, lower IL2 and higher TNF alpha and IFN gamma production. In the ICI-pooled population (N = 83), SIP+ status did not correlate with any clinical characteristics and it was associated with significantly worse ORR, PFS, and OS. In PCT cohort (N = 61), 11% of patients were SIP+. SIP status did not correlate with outcomes upon PCT.Conclusions: Circulating T-cell immunosenescence is observed in up to 28% of patients with aNSCLC and correlates with lack of benefit from ICI but not from PCT

Relationships between seed and berry development of Vitis Vinifera L. cv Shiraz: Developmental changes in seed morphology and phenolic composition

Berries were collected regularly from fruit set to berry maturity from irrigated (Shiraz) grapevines in a Barossa valley vineyard. Seeds were removed for detailed study of physical attributes (weight, moisture, colour) and phenolic composition (seed tannins). Three phases of seed growth and development were discerned: (1) a phase of seed growth characterised by a steady increase in both fresh weight and dry weight, biosynthesis and accumulation of flavan-3-ols and tannins, and green appearance; (2) a transition phase where seed fresh weight and dry weight reached a maximum, but with continuing enlargement of the basal end. Accumulation of flavan-3-ols and seed tannins also reached a maximum during phase 2, and was accompanied by an onset of tannin oxidation, and yellow appearance; and finally, (3) a phase of seed drying and maturation defined by a decrease in fresh weight due to water export, a sustained oxidation of tannins, and overall brown appearance. These phases in seed development correspond to particular stages in berry development. Seeds reached maximum fresh seed weight and full size at the beginning of berry colouring (veraison), while maximum dry seed weight coincided with maximum berry weight. Changes in seed phenolics were linked to berry development and maturation. Changes in seed coat colour were also related to developmental changes in berry anthocyanins and total skin phenolics, indicating that the external appearance and colour of the seed coat may be used as an additional indicator of overall berry ripeness. A graduated colour chart was developed to provide an objective index of seed coat colour and thus developmental status of seeds and berry

HELGA VI. Giant molecular cloud associations in M31

VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The Herschel Exploitation of Local Galaxy Andromeda (HELGA). VI. The distribution and properties of molecular cloud associations in M31.' (bibcode: 2015ApJ...798...58K