Effects of thickness on the spin susceptibility of the 2D electron gas

Using available quantum Monte Carlo predictions for a strictly 2D electron gas, we have estimated the spin susceptibility of electrons in actual devices taking into account the effect of the finite transverse thickness and finding a very good agreement with experiments. A weak disorder, as found in very clean devices and/or at densities not too low, just brings about a minor enhancement of the susceptibility.Comment: 4 pages, 3 figure

Spin Susceptibility of Interacting Two-dimensional Electrons with Anisotropic Effective Mass

We report measurements of the spin susceptibility in dilute (rs up to 10) AlAs two-dimensional (2D) electrons occupying a single conduction-band valley with an anisotropic in-plane Fermi contour, characterized by longitudinal and transverse effective masses, ml and mt. As the density is decreased, the spin susceptibility is significantly enhanced over its band value, reflecting the role of interaction. Yet the enhancement is suppressed compared to the results of quantum Monte Carlo based calculations that take the finite thickness of the electron layer into account but assume an isotropic effective mass equal to sqrt(ml.mt). Proper treatment of an interacting 2D system with an anisotropic effective mass therefore remains a theoretical challenge.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev.

Role of Alcian blue (pH 2.5) histochemical stain in diagnostic thyroid pathology: how far is it helpful?

Background: Controversies and pitfalls are well-known in diagnostic thyroid pathology. Since, the luminal surface of  neoplastic thyroid follicular cells is said to be covered by a glycoproteinaceous material, there is a need  to  investigate the efficacy of  mucin stains like Alcian blue (pH 2.5), which can be used as an adjunctive tool in difficult cases.Methods: 60 thyroidectomy specimens, received at Department of Pathology, were included in this retrospective analytical study. Alcian blue histochemical (pH 2.5) staining was done on representative sections and assessed for positivity.Results: Of the 60 cases analysed, all cases of papillary/nodular hyperplasia (n=10), follicular adenoma (n=14), follicular carcinoma (n=4) and medullary carcinoma (n=1) were negative for Alcian blue. Only 3/16 (18.7 %) cases of classical papillary carcinoma and 2/15 (13.3%) cases of follicular variant of papillary carcinoma showed positivity.Conclusions: We got statistically insignificant results with Alcian blue (pH 2.5) staining, making it unreliable in diagnostic thyroid pathology

Disorder effect on the spin susceptibility of the two-dimensional one-valley electron gas

Starting from the quantum Monte Carlo (QMC) prediction for the ground-state energy of a clean two-dimensional one-valley (2D1V) electron gas, we estimate the energy correction due to scattering sources present in actual devices such as AlAs quantum wells and GaAs heterostructures. We find that the effect of uncorrelated disorder, in the lowest (second) order in perturbation theory, is to enhance the spin susceptibility leading to its eventual divergence. In the density region where the Born approximation is able to reproduce the experimental mobility, the prediction for the spin susceptibility yielded by perturbation theory is in very good agreement with the available experimental evidence.Comment: 9 pages, 3 figures, special issue article for the SCCS2008 conference (Camerino, Italy

Correlation Energy and the Spin Susceptibility of the Two-Valley Two-dimensional Electron Gas

We find that the spin susceptibility of a two-dimensional electron system with valley degeneracy does not grow critically at low densities, at variance with experimental results [A. Shashkin et al., Phys. Rev. Lett. 96, 036403 (2006)]. We ascribe this apparent discrepancy to the weak disorder present in experimental samples. Our prediction is obtained from accurate correlation energies computed with state of-the-art diffusion Monte Carlo simulations and fitted with an analytical expression which also provides a local spin density functional for the system under investigation.Comment: 7 pages, 3 figures, accepted for publication in Phys. Rev.

Penggunaan Atraktor Buatan Yang Ramah Lingkungan Dalam Pemanenan Anakan Udang Lobster Laut (Panulirus Spp)

Spiny lobster (Panulirus spp) is one of important commodities in Bulukumba Regency. The lobsters used for aquaculture were obtained from the wild catch in the sea. The purpose of this study was to develop artificial gear to attract the lobster seed to beeasily caught. The research was conducted in marine coastal of Ujung Bulu, Bulukumba Regency, South Sulawesi from July to October 2013. There are three artificial attractors that consisted of light attractor, trap shelter attractor, and shelter benthic attractor. Results showed that the spiny lobster catches from artificial attractor consisted of 47.5 % of pearl lobster (Panulirus ornatus), 25.8% of sand lobster (P. homarus), 21.2 % of bamboo lobster (P. versi color), 5.6% of stone lobster (P. penicilatus). The carapace length of both pearl lobsterand sand lobster ranged from 2,6 to 6,0 cm, which were longest among the other lobsters.

Value co-creation practices and capabilities: sustained purposeful engagement across B2B systems

The paradigm of value co-creation in business markets is now well established in the marketing literature. However, the practices and capabilities for collaborative value co-creation are less understood, particularly in increasingly boundary-less interorganizational, network and ecosystem relationships. This paper describes sets of practices that organizations in business markets adopt to co-create value. We provide a theoretically-grounded, empirically-informed classification of value co-creating practices, identifying the underlying capabilities needed to realize value in B2B systems. We adopt a case study approach utilizing various methods of data collection to explore co-creation practices from four organizations. The analysis reveals that ‘sustained purposeful engagement’ underpins the organizations' ability to co-create and capture value. Implications for organizations willing to develop co-creation capabilities and practices are discussed