Ricardo García

Changes in the relationship NAO–Northern hemisphere temperature due to solar activity

Abstract The influence of the North Atlantic Oscillation (NAO) on wintertime Northern Hemisphere Temperature (NHT) is investigated. The results suggest that this relationship has different sign according to the phase of the solar cycle. For solar maximum phases NAO and NHT are positively correlated – a result assumed up to the moment – but for solar minimum phases correlations are not significant or even negative. This result is in agreement with the different extension of the NAO for solar cycle phases [Kodera, Geophys. Res. Lett. 29 (2002) 14557–14560] – almost hemispheric for maximum phases and confined to the eastern Atlantic for minimum phases.

Risk Factors Predicting Infectious Lactational Mastitis: Decision Tree Approach versus Logistic Regression Analysis

Objectives Lactational mastitis frequently leads to a premature abandonment of breastfeeding; its development has been associated with several risk factors. This study aims to use a decision tree (DT) approach to establish the main risk factors involved in mastitis and to compare its performance for predicting this condition with a stepwise logistic regression (LR) model. Methods Data from 368 cases (breastfeeding women with mastitis) and 148 controls were collected by a questionnaire about risk factors related to medical history of mother and infant, pregnancy, delivery, postpartum, and breastfeeding practices. The performance of the DT and LR analyses was compared using the area under the receiver operating characteristic (ROC) curve. Sensitivity, specificity and accuracy of both models were calculated. Results Cracked nipples, antibiotics and antifungal drugs during breastfeeding, infant age, breast pumps, familial history of mastitis and throat infection were significant risk factors associated with mastitis in both analyses. Bottle-feeding and milk supply were related to mastitis for certain subgroups in the DT model. The areas under the ROC curves were similar for LR and DT models (0.870 and 0.835, respectively). The LR model had better classification accuracy and sensitivity than the DT model, but the last one presented better specificity at the optimal threshold of each curve. Conclusions The DT and LR models constitute useful and complementary analytical tools to assess the risk of lactational infectious mastitis. The DT approach identifies highrisk subpopulations that need specific mastitis prevention programs and, therefore, it could be used to make the most of public health resources.

Imprints of the North Atlantic Oscillation on four unusual atmospheric parameters

Abstract Using data for 41 yr (1958–1998) from the National Center for Environmental Prediction–National Center for Atmospheric Research reanalysis the authors study the impact of the North Atlantic Oscillation (NAO) on four atmospheric parameters. These four parameters have three common characteristics: their previous limited use as climate diagnosis tools, their high dependence on changes in atmospheric circulation and their relationship with variables associated with the development of synoptic perturbances. They are: (1) relative angular momentum from 500 hPa to 200 hPa and from 55°N to 90°N, (2) advection of temperature at 500 hPa, (3) equivalent temperature at 850 hPa and (4) distribution of upper level low systems (ULL). The most significant results are: (1) a significant positive correlation between the relative angular momentum from 500 hPa to 200 hPa and from 55°N to 90 °N with the NAO index computed as the normalized pressure difference between Ponta Delgada (Azores) and Reykjavik (Iceland), (2) the NAO affects 500 hPa temperature advection from 45°N to 70°N and a positive NAO index is alternatively related to positive or negative anomalies of advection. The relationship is positive over the Atlantic, Asia and Western America and negative over Europe, the Pacific and Eastern America. (3) The correlation pattern between NAO index and the equivalent temperature at 850 hPa shows a semiannular structure with negative correlations over the Arctic and positive correlations over midlatitudes with the exception of the Pacific area, and (4) the distribution of ULL systems is only influenced by NAO over both sides of the Atlantic Ocean and for the latitude belt from 20°N to 50°N.

The use of atmospheric relative angular momentum to diagnose the Arctic oscillation

Abstract Recent studies suggest that the North Atlantic Oscillation is a regional expression of the Northern Hemisphere Annular Mode. However, the lack of an apparent link between Atlantic and Pacific sectors questions the annular paradigm. In any case, the phenomenon is the largest and most fundamental mode of variability in the Northern Hemisphere troposphere, being responsible for much of the warming in the Northern Hemisphere surface temperature. The main aim of this study is to diagnose the Northern Hemisphere Annular Mode using an annular magnitude, such as the relative angular momentum (RAM). RAM from 500 hPa to 200 hPa is computed for the polar cap, using 60° longitude sectors as well as the whole cap, from 55 to 90°N and for the period 1958–1998, using NCEP-NCAR reanalysis data. Annual values of RAM are then correlated to temperature and geopotential height at 200, 500 and 850 hPa. The Artic region is dominated by very negative correlations for the Northern Hemisphere RAM and for the six different RAM sectors. Midlatitudes are dominated by positive correlation, with intermittent or alternating significant regions not showing a regular annular pattern. The Pacific Ocean area is only significantly correlated with the Pacific RAM sector. Since an annular pattern is characterized by its hemispheric symmetry, two symmetric latitude rings are expected, but only the polar one is detected, the rest being incomplete. Due to the proximity of the grid points near the pole, which can lead to artificial zonal symmetry, all the calculations are repeated for RAM from 45 to 65°N, finding a similar pattern with lower correlations and less symmetry. So the results do not support the annular paradigm, understood as organized along latitude sectors, but a hemispheric dimension cannot be excluded.

Los Tribunales Constitucionales y el control del Derecho interno conectado con el Comunitario

Analysis of the role of national Courts within the European Union, including Constitutional (or Supreme) Courts, before domestic Law implementing Community Law. An effort to avoid, as far as possible, declaring the unconstitutionality of domestic Law, which could entail unnecessary or incoherent declarations of unconstitutionality of Community Law.