Multivariate manifold-valued curve regression in time

Fr\'echet global regression is extended to the context of bivariate curve stochastic processes with values in a Riemannian manifold. The proposed regression predictor arises as a reformulation of the standard least-squares parametric linear predictor in terms of a weighted Fr\'echet functional mean. Specifically, in our context, in this reformulation, the Euclidean distance is replaced by the integrated quadratic geodesic distance. The regression predictor is then obtained from the weighted Fr\'echet curve mean, lying in the time-varying geodesic submanifold, generated by the regressor process components involved in the time correlation range. The regularized Fr\'echet weights are computed in the time-varying tangent spaces. The uniform weak-consistency of the regression predictor is proved. Model selection is also addressed. A simulation study is undertaken to illustrate the performance of the spherical curve variable selection algorithm proposed in a multivariate framework.Comment: 24 pages, 8 Figure

Consumption patterns: A proposed model for measurement of solution palatability in pigs

In animal production, the palatability of feeds or solutions has typically been inferred from measurements of preference or acceptance. However, laboratory studies in rats have demonstrated that palatability quantified through the analysis of the microstructure of licking can dissociate from simple measures of consumption. The aim of this study was to evaluate palatability in pigs by using consumption patterns. Pigs (n = 24) were exposed (in pairs, with video recording) to different sucrose solutions (0.5, 1, 2, 4, 8, 16, and 32%) over 7 consecutive 10-min tests (1 concentration/d). Total consumption, number of consumption approaches (A), and real consumption time (RCT) were measured. Palatability was estimated through consumption pattern (RCT/A), analogous to the licks/bout measure used in rats. Data was analyzed by sucrose concentration. Spearman correlation coefficients were estimated between the logarithm of sucrose concentration and total consumption, A, RCT, and RCT/A. Total consumption and RCT showed inverted U functions relative to sucrose concentration. Consumption pattern (RCT/A) presented a dose effect (P < 0.005) and positive correlations with sucrose concentration (R = 0.23, P = 0.034). As with rats, consumption pattern could represent an interesting and novel measure of feeding behavior, reflecting palatability in pigs

Downscaling ECMWF seasonal precipitation forecasts in Europe using the RCA model

6 páginas, 4 figuras.--Licencia Creative Commons Reconocimiento-No comercial 3.0The operational performance and usefulness of regional climate models at seasonal time scales are assessed by downscaling an ensemble of global seasonal forecasts. The Rossby Centre RCA regional model was applied to downscale a five-member ensemble from the ECMWF System3 global model in the European Atlantic domain for the period 1981–2001. One month lead time global and regional precipitation predictions were compared over Europe—and particularly over Spain—focusing the study in SON (autumn) dry events. A robust tercile-based probabilistic validation approach was applied to compare the forecasts from global and regional models, obtaining significant skill in both cases, but over a wider area for the later. Finally, we also analyse the performance of a mixed ensemble combining both forecasts.This work was partly supported by projects ENSEMBLES from the 6th FP EU(GOCE-CT-2003-505539), EXTREMBLES (CGL2010-21869) and CORWES (CGL2010-22158-C02) from the Spanish Ministry MICINN (Plan Nacional de I+D+i) and by ESCENA (200800050084265) from the Spanish Ministry MARM.Peer reviewe