In vivo contact stresses at the radiocarpal joint using a finite element method of the complete wrist joint

A small number of cadaveric studies have been carried out looking at the force transmission through the radiocarpal joint. In this study subject specific finite element models were created of the whole wrist joint using measured biomechanical data to capture the forces acting on the wrist with the hand generating a maximum gripping force

Fundamental relation between longitudinal and transverse conductivities in the quantum Hall system

We investigate the relation between the diagonal ($\sigma_{xx}$) and off-diagonal ($\sigma_{xy}$) components of the conductivity tensor in the quantum Hall system. We calculate the conductivity components for a short-range impurity potential using the linear response theory, employing an approximation that simply replaces the self-energy by a constant value $-i \hbar /(2 \tau)$ with $\tau$ the scattering time. The approximation is equivalent to assuming that the broadening of a Landau level due to disorder is represented by a Lorentzian with the width $\Gamma = \hbar /(2 \tau)$. Analytic formulas are obtained for both $\sigma_{xx}$ and $\sigma_{xy}$ within the framework of this simple approximation at low temperatures. By examining the leading terms in $\sigma_{xx}$ and $\sigma_{xy}$, we find a proportional relation between $\mathrm{d}\sigma_{xy}/\mathrm{d}B$ and $B \sigma_{xx}^2$. The relation, after slight modification to account for the long-range nature of the impurity potential, is shown to be in quantitative agreement with experimental results obtained in the GaAs/AlGaAs two-dimensional electron system at the low magnetic-field regime where spin splitting is negligibly small.Comment: 21 pages, 8 figures, accepted for publication in J. Phys.: Condens. Matte

Magnetoroton scattering by phonons in the fractional quantum Hall regime

Motivated by recent phonon spectroscopy experiments in the fractional quantum Hall regime we consider processes in which thermally excited magnetoroton excitations are scattered by low energy phonons. We show that such scattering processes can never give rise to dissociation of magnetorotons into unbound charged quasiparticles as had been proposed previously. In addition we show that scattering of magnetorotons to longer wavelengths by phonon absorption is possible because of the shape of the magnetoroton dispersion curve and it is shown that there is a characteristic cross-over temperature above which the rate of energy transfer to the electron gas changes from an exponential (activated) to a power law dependence on the effective phonon temperature.Comment: LaTex document, 3 eps figures. submitted to Phys Rev

Dirac Quantization of Two-Dimensional Dilaton Gravity Minimally Coupled to N Massless Scalar Fields

It is shown that the Callan-Giddings-Harvey-Strominger theory on the cylinder can be consistently quantized (using Dirac's approach) without imposing any constraints on the sign of the gravitational coupling constant or the sign (or value) of the cosmological constant. The quantum constraints in terms of the original geometrical variables are also derived

Canonical Equivalence of a Generic 2D Dilaton Gravity Model and a Bosonic String Theory

We show that a canonical tranformation converts, up to a boundary term, a generic 2d dilaton gravity model into a bosonic string theory with a Minkowskian target space.Comment: LaTeX file, 9 pages, no figure

Monitoring of compliance in Australian conservation contracts

Government and non-government conservation agencies have long-term goals and objectives to provide environmental services, such as conserving the biodiversity of Australian native vegetation. In addition to national parks and reserves, private lands are often included in conservation programs to achieve these objectives. Formal contracts are entered into between the private landholder and the conservation agency to provide environmental services, or more commonly to provide inputs that are likely to lead to environmental services. The paper examines the costs and benefits of monitoring these conservation contracts when biodiversity change is stochastic.conservation, compliance, monitoring, enforcement, environmental regulation, Environmental Economics and Policy,

Key Determinants of China’s Outward FDI to Africa

China’s FDI in Africa is closely linked to trade and development assistance. Thus, it is an appropriate time to untangle key factors that determine the China’s investment to Africa. FDI has increased over the past decade in tandem with increased Sino-African trade, although China’s FDI to Africa remains marginal in terms of China’s total outward FDI flows According to the Chinese Ministry of Commerce, China’s FDI in Africa has increased by 46% per year over the last decade. During the first half of 2009, Chinese FDI flows into Africa increased by 81% compared to the same period in 2008, reaching over US$0.5 billion. However, it is difficult to be certain about the level of China’s FDI outflows, as estimates from different sources vary widely and Chinese investments are often channeled through off-shore entities registered in places such as Hong Kong, Cayman Island and others. China has served as a development model for Africa and an alternative source of trade and finance from Africa’s traditional development partners. Undeniably, the impact of China on African economies has been diverse, depending in part on the sectorial composition of each country’s production. Overall, China’s increased engagement with Africa could generate important gains for African economies. The aim of this paper is to analyze the various key determinants of China’s outward FDI for a sample of selected African economies and a panel data analysis has been used in the study. The time frame for analysis is a 7-year period, 2005-2011 and 43 African countries are involved in this study, based on data availability. The Hausman test specification, recommended the use of fixed effects model. An empirical analysis reveals that China’s outward FDI to Africa responds positively to openness, resource seeking and market opportunities ties. For example, China’s OFDI tends to go to countries with a good market size as measured by host country GDP and GDP growth, China’s export to a host country and export of goods and services percentage of host country GDP. Their per capita GDP had no impact on FDI flows. Surprisingly, the political stability and absence of violence/terrorism factors are found to “have no tie” with Chinese outward foreign direct investment. Keywords: African host countries, China, Outward FDI, Key determinant