Seeking Sustainability: COSA preliminary analysis of sustainability initiatives in the coffee sector

The growing economic value and consumer popularity of sustainability standards inevitably raise questions about the extent to which their structure and dynamics actually address many environmental, economic and public welfare issues. The Committee on Sustainable Assessment (COSA) was formed, in part, to develop a scientifically credible framework capable of assessing the impacts associated with the adoption of sustainability initiatives. This paper examines the pilot phase of vetting and testing the COSA method, an innovative management tool used to gather and analyze data using economic, environmental and social metrics.sustainability initiatives, standards, organic, fair trade, Rainforest, social, environmental, economic certification

Vortex core size in interacting cylindrical nanodot arrays

The effect of dipolar interactions among cylindrical nanodots, with a vortex-core magnetic configuration, is analyzed by means of analytical calculations. The cylinders are placed in a N x N square array in two configurations - core oriented parallel to each other and with antiparallel alignment between nearest neighbors. Results comprise the variation in the core radius with the number of interacting dots, the distance between them and dot height. The dipolar interdot coupling leads to a decrease (increase) of the core radius for parallel (antiparallel) arrays

Superconductivity in Artificial Nb/Cu Heterostructures

Transport and tunneling measurements of artivicially prepared Nb/Cu heterostructures have been made. Samples studied had individual layers in the range 3.6 to 5000 A with total thickness approx. 1 ..mu..m. The dependence of T/sub c/ above 300 A layer thickness agrees well with proximity effect theory with no adjustable parameters. Below 300 A the data indicate the T/sub c/ of Nb decreases with layer thickness. The coupling strength 2..delta../kT/sub c/ exhibits a continuous decrease from the strong coupled value of approx. 3.8 (thick layers) toward the weak coupled value of approx. 3.5 (thin layers). No evidence is found for a change in the Nb LA and TA phonons energies from their bulk values down to approx. 10 A. These results, in conjunction with Brillouin scattering measurements of zone center phonons, imply large changes in the phonon dispersion relation as a function of layer thickness in these materials

Flux pinnig in a superconductor by an array of submicrometer magnetic dots

Triangular arrays of submicrometer magnetic dots, with typical spacing of 400-600 nm and diameters close to 200 nm, have been fabricated by electron beam lithography to study pinning effects on Nb thin films. The resistivity versus magnetic field curves exhibit regular structure. Minima appear at constant field intervals, given by the lattice parameter of the dot array. The angular, current, and temperature dependencies of the resistivity imply synchronized pinning by the magnetic array which is relevant at high vortex velocities, when the order in the vortex lattice increases

Evolution of the local superconducting density of states in ErRh4_4B4_{4} close to the ferromagnetic transition

We present local tunneling spectroscopy experiments in the superconducting and ferromagnetic phases of the reentrant superconductor ErRh$_4$B$_{4}$. The tunneling conductance curves jump from showing normal to superconducting features within a few mK close to the ferromagnetic transition temperature, with a clear hysteretic behavior. Within the ferromagnetic phase, we do not detect any superconducting correlations. Within the superconducting phase we find a peculiar V-shaped density of states at low energies, which is produced by the magnetically modulated phase that coexists with superconductivity just before ferromagnetism sets in.Comment: 5 pages, 4 figure

Deviation from bulk in the pressure-temperature phase diagram of V2O3 thin films

We found atypical pressure dependence in the transport measurements of the metal to insulator transition (MIT) in epitaxial thin films of vanadium sesquioxide (V2O3). Three different crystallographic orientations and four thicknesses, ranging from 40 to 500 nm, were examined under hydrostatic pressures (P-h) of up to 1.5 GPa. All of the films at transition exhibited a four order of magnitude resistance change, with transition temperatures ranging from 140 to 165 K, depending on the orientation. This allowed us to build pressure-temperature phase diagrams of several orientations and film thicknesses. Interestingly, for pressures below 500 MPa, all samples deviate from bulk behavior and show a weak transition temperature (T-c) pressure dependence (dT(c)/dP(h) = 1.2 x 10(-2) +/- 0.3 x 10(-2) K/MPa), which recovers to bulklike behavior (3.9 x 10(-2) +/- 0.3 x 10(-2) K/MPa) at higher pressures. Furthermore, we found that pressurization leads to morphological but not structural changes in the films. This indicates that the difference in the thin film and bulk pressure-temperature phase diagrams is most probably due to pressure-induced grain boundary relaxation, as well as both plastic and elastic deformations in the film microstructure. These results highlight the difference between bulk and thin films behaviors

Switchable collective pinning of flux quanta using magnetic vortex arrays

We constructed a superconducting/ferromagnetic hybrid system in which the ordering of the pinning potential landscape for flux quanta can be manipulated. Flux pinning is induced by an array of magnetic nanodots in the magnetic vortex state, and controlled by the magnetic history. This allows switching on and off the collective pinning of the flux-lattice. In addition, we observed field-induced superconductivity that originates from the annihilation of flux quanta induced by the stray fields from the magnetic vortices.Comment: PDF file 18 pages including 5 figures, accepted for publication in Phys. Rev.

Speaker-independent emotion recognition exploiting a psychologically-inspired binary cascade classification schema

In this paper, a psychologically-inspired binary cascade classification schema is proposed for speech emotion recognition. Performance is enhanced because commonly confused pairs of emotions are distinguishable from one another. Extracted features are related to statistics of pitch, formants, and energy contours, as well as spectrum, cepstrum, perceptual and temporal features, autocorrelation, MPEG-7 descriptors, Fujisakis model parameters, voice quality, jitter, and shimmer. Selected features are fed as input to K nearest neighborhood classifier and to support vector machines. Two kernels are tested for the latter: Linear and Gaussian radial basis function. The recently proposed speaker-independent experimental protocol is tested on the Berlin emotional speech database for each gender separately. The best emotion recognition accuracy, achieved by support vector machines with linear kernel, equals 87.7%, outperforming state-of-the-art approaches. Statistical analysis is first carried out with respect to the classifiers error rates and then to evaluate the information expressed by the classifiers confusion matrices. © Springer Science+Business Media, LLC 2011