Search results for "scale [mass]"

The resonant state at filling factor {\nu} = 1/2 in chiral fermionic ladders

2017

Helical liquids have been experimentally detected in both nanowires and ultracold atomic chains as the result of strong spin-orbit interactions. In both cases the inner degrees of freedom can be considered as an additional space dimension, providing an interpretation of these systems as synthetic ladders, with artificial magnetic fluxes determined by the spin-orbit terms. In this work, we characterize the helical state which appears at filling $\nu=1/2$: this state is generated by a gap arising in the spin sector of the corresponding Luttinger liquid and it can be interpreted as the one-dimensional (1D) limit of a fractional quantum Hall state of bosonic pairs of fermions. We study its main…

The socio-economic impact of transnational corporation on mining community and artisanal small-scale miners : a case study of Mererani Tanzania

2006

An urban multi-­scale modeling using fuzzy evaluation of accessibility and morphological constraints

2008

International audience; Increasing mobility has contributed since a couple of years to favor urban sprawl. The negative impacts of urban sprawl are well known, in particular the increase of traffic flows and vulnerability of natural resources. Addressing those questions we propose a spatial decision support system based on a multi-scale approach. On the one hand, fractal geometry is used to determine where new urban developments are possible. Here, the central assumption is the fractal nature of urban growth allowing access to various types of amenities: central amenities (retailing, cultural offer...) and peripheral amenities (open landscape). On the other hand, the accessibility to retail…

Pathways for the amplification of agroecology in African sustainable urban agriculture

2020

A growing awareness that highly intensified agricultural systems have made a substantial worldwide contribution to the worsening of the resilience capacity of natural ecosystems has, over the last twenty years, brought general attention to agroecological management models. This aspect is even more evident in industrial agriculture, which is based on the use of multiple chemical products derived from non-natural synthesis. In more developed countries, a new idea of ecology linked to agricultural production has been increasingly developed and, for this reason, there has been a greater diffusion of differentiated agricultural models taking into consideration the environmental impact of product…

The meaningfulness of two curriculum-based national tests of English as a foreign language

2022

This paper addresses the aspect of the meaningfulness of a national assessment in English as a foreign language, applying the fairness framework proposed by Kunnan (2018). We compared students’ performance on two receptive language skills of listening and reading on two subsequent national evaluations in Finland, taken by students at the end of compulsory basic education and at the end of general upper secondary education, respectively. The research questions focus on (1) the relationship between students’ performance on the two tests and their gender, language of schooling and parents’ educational level, and (2) the relationship between the students’ receptive language proficiency at the e…

Acoustic wave tunneling across a vacuum gap between two piezoelectric crystals with arbitrary symmetry and orientation

2022

It is not widely appreciated that an acoustic wave can “jump” or “tunnel” across a vacuum gap between two piezoelectric solids, nor has the general case been formulated or studied in detail. Here, we remedy that situation, by presenting a general formalism and approach to study such an acoustic tunneling effect between two arbitrarily oriented anisotropic piezoelectric semi-infinite crystals. The approach allows one to solve for the reflection and transmission coefficients of all the partial-wave modes, and is amenable to practical numerical or even analytical implementation, as we demonstrate by a few chosen examples. The formalism can be used in the future for quantitative studies of the …

Energy Efficient Optimization for Wireless Virtualized Small Cell Networks With Large-Scale Multiple Antenna

2017

Wireless network virtualization is envisioned as a promising framework to provide efficient and customized services for next-generation wireless networks. In wireless virtualized networks (WVNs), limited radio resources are shared among different services providers for providing services to different users with heterogeneous demands. In this paper, we propose a resource allocation scheme for an orthogonal frequency division multiplexing-based WVN, where one small cell base station equipped with a large number of antennas serves the users with different service requirements. In particular, with the objective to obtain the energy efficiency in the uplink, a joint power, subcarrier, and antenn…