Investigation of the coupling asymmetries at double-slit interference experiments

Double-slit experiments inferring the phase and the amplitude of the transmission coefficient performed at quantum dots (QD), in the Coulomb blockade regime, present anomalies at the phase changes depending on the number of electrons confined. This phase change cannot be explained if one neglects the electron-electron interactions. Here, we present our numerical results, which simulate the real sample geometry by solving the Poisson equation in 3D. The screened potential profile is used to obtain energy eigenstates and eigenvalues of the QD. We find that, certain energy levels are coupled to the leads stronger compared to others. Our results give strong support to the phenomenological models in the literature describing the charging of a QD and the abrupt phase changes.Comment: conference paper, 50th anniversary of Aharonov-Bohm effec

The predictive effect of teachers’ perception of school principals’ motivating language on teachers’ self-efficacy via a cultural context

The aim of the study is to investigate the relationship between teachers' perception of school principals' motivating language and teachers' self-efficacy mediated by the cultural context. School principals' linguistic communication skills are critical to sustain the motivation of teachers and their self-efficacy. Motivating language theory (MLT), on which this study is based, provides a model that helps us understand how the language, more precisely, the speech acts, used by school principals have an impact on teachers' self-efficacy. A survey method was employed with 252 teachers through convenience sampling. The teachers' mean age was 34.87 (SD = 9.22) years, and the average length of service was 11.72 (SD = 9.42) years. The results showed that school principals' use of motivating language was significantly and positively associated with teachers' self-efficacy (b = 0.10, p < 0.000). The low-context culture was found to have a full mediating effect in this relationship (b = 0.04, t = 3.1771, p < 0.000). The findings contribute to leader communication theory by highlighting a particular emphasis on the language school principals use to motivate teachers

The relationships of phenotype, genotype and some environmental factors with birth weight in Jersey calves

This study investigated the effects of parity, birth type, gender and birth season on birth weight in Jersey cattle and also investigated the relationships of phenotype and genotype with birth weight. Birth records of the Karakoy farm near Samsun, Turkey for the period from 1998 to 2005 were used as data for this study. Parity (P < 0.001), birth type (P < 0.001) and gender (P < 0.001) had a significant effect on birth weight, whereas season of calving and calving year (P > 0.05) were not significant. The birth weight mean of Jersey calves was 20.87 ± 1.79 kg. Total additive genotypic variance was 14.80, phenotypic variance was 38.95 and heritability of birth weight was 0.38. In planning a selection program to achieve ideal birth weight of Jersey calves, birth type, gender and parity need to be included, with the 4th or later parity been most influential.Key words: Birth weight, estimate of parameter, Jersey, parity, season of birth

Fermion Quasi-Spherical Harmonics

Spherical Harmonics, $Y_\ell^m(\theta,\phi)$, are derived and presented (in a Table) for half-odd-integer values of $\ell$ and $m$. These functions are eigenfunctions of $L^2$ and $L_z$ written as differential operators in the spherical-polar angles, $\theta$ and $\phi$. The Fermion Spherical Harmonics are a new, scalar and angular-coordinate-dependent representation of fermion spin angular momentum. They have $4\pi$ symmetry in the angle $\phi$, and hence are not single-valued functions on the Euclidean unit sphere; they are double-valued functions on the sphere, or alternatively are interpreted as having a double-sphere as their domain.Comment: 16 pages, 2 Tables. Submitted to J.Phys.

Senescence and immortality in hepatocellular carcinoma

Cataloged from PDF version of article.Cellular senescence is a process leading to terminal growth arrest with characteristic morphological features. This process is mediated by telomere-dependent, oncogene-induced and ROS-induced pathways, but persistent DNA damage is the most common cause. Senescence arrest is mediated by p16(INK4a)- and p21(Cip1)-dependent pathways both leading to retinoblastoma protein (pRb) activation. p53 plays a relay role between DNA damage sensing and p21(Cip1) activation. pRb arrests the cell cycle by recruiting proliferation genes to facultative heterochromatin for permanent silencing. Replicative senescence that occurs in hepatocytes in culture and in liver cirrhosis is associated with lack of telomerase activity and results in telomere shortening. Hepatocellular carcinoma (HCC) cells display inactivating mutations of p53 and epigenetic silencing of p16(INK4a). Moreover, they re-express telomerase reverse transcriptase required for telomere maintenance. Thus, senescence bypass and cellular immortality is likely to contribute significantly to HCC development. Oncogene-induced senescence in premalignant lesions and reversible immortality of cancer cells including HCC offer new potentials for tumor prevention and treatment. (C) 2008 Elsevier Ireland Ltd. All rights reserved

Realistic modelling of quantum point contacts subject to high magnetic fields and with current bias at out of linear response regime

The electron and current density distributions in the close proximity of quantum point contacts (QPCs) are investigated. A three dimensional Poisson equation is solved self-consistently to obtain the electron density and potential profile in the absence of an external magnetic field for gate and etching defined devices. We observe the surface charges and their apparent effect on the confinement potential, when considering the (deeply) etched QPCs. In the presence of an external magnetic field, we investigate the formation of the incompressible strips and their influence on the current distribution both in the linear response and out of linear response regime. A spatial asymmetry of the current carrying incompressible strips, induced by the large source drain voltages, is reported for such devices in the non-linear regime.Comment: 16 Pages, 9 Figures, submitted to PR

What is the scientific basis for climate-smart agriculture?

Climate-smart agriculture (CSA) is a systematic approach to agricultural development. It intends to address climate change and food security challenges simultaneously across levels, from field management to national policy, with goals to 1) improve food security and agricultural productivity, 2) increase the resilience of farming systems to climate change, and 3) mitigate greenhouse gas (GHG) emissions or sequester carbon. After the introduction of the CSA concept in 2010, development organizations, national governments, and donors have quickly adopted a “climate-smart” agenda

Human brain mapping: a systematic comparison of parcellation methods for the human cerebral cortex

The macro-connectome elucidates the pathways through which brain regions are structurally connected or functionally coupled to perform a specific cognitive task. It embodies the notion of representing and understanding all connections within the brain as a network, while the subdivision of the brain into interacting functional units is inherent in its architecture. As a result, the definition of network nodes is one of the most critical steps in connectivity network analysis. Although brain atlases obtained from cytoarchitecture or anatomy have long been used for this task, connectivity-driven methods have arisen only recently, aiming to delineate more homogeneous and functionally coherent regions. This study provides a systematic comparison between anatomical, connectivity-driven and random parcellation methods proposed in the thriving field of brain parcellation. Using resting-state functional MRI data from the Human Connectome Project and a plethora of quantitative evaluation techniques investigated in the literature, we evaluate 10 subject-level and 24 groupwise parcellation methods at different resolutions. We assess the accuracy of parcellations from four different aspects: (1) reproducibility across different acquisitions and groups, (2) fidelity to the underlying connectivity data, (3) agreement with fMRI task activation, myelin maps, and cytoarchitectural areas, and (4) network analysis. This extensive evaluation of different parcellations generated at the subject and group level highlights the strengths and shortcomings of the various methods and aims to provide a guideline for the choice of parcellation technique and resolution according to the task at hand. The results obtained in this study suggest that there is no optimal method able to address all the challenges faced in this endeavour simultaneously