A Hubble Space Telescope/NICMOS view of the prototypical giant Hii region NGC604 in M33

We present the first high-spatial-resolution near-infrared (NIR) imaging of NGC604, obtained with the NICMOS camera onboard the Hubble Space Telescope (HST). These NICMOS broad-band images reveal new NIR point sources, clusters, and diffuse structures. We find an excellent spatial correlation between the 8.4 GHz radio continuum and the 2.2 μm nebular emission. Moreover, massive young stellar object candidates appear aligned with these radio peaks, reinforcing the idea that those areas are star-forming regions. Three different scaled OB associations are recognized in the NICMOS images. The brightest NIR sources in our images have properties that suggest that they are red supergiant stars, of which one was previously known. This preliminary analysis of the NICMOS images shows the complexity of the stellar content of the NGC604 nebula.     

A special perturbation method in orbital dynamics

The special perturbation method considered in this paper combines simplicity of computer implementation, speed and precision, and can propagate the orbit of any material particle. The paper describes the evolution of some orbital elements based in Euler parameters, which are constants in the unperturbed problem, but which evolve in the time scale imposed by the perturbation. The variation of parameters technique is used to develop expressions for the derivatives of seven elements for the general case, which includes any type of perturbation. These basic differential equations are slightly modified by introducing one additional equation for the time, reaching a total order of eight. The method was developed in the Grupo de Dinámica de Tethers (GDT) of the UPM, as a tool for dynamic simulations of tethers. However, it can be used in any other field and with any kind of orbit and perturbation. It is free of singularities related to small inclination and/or eccentricity. The use of Euler parameters makes it robust. The perturbation forces are handled in a very simple way: the method requires their components in the orbital frame or in an inertial frame. A comparison with other schemes is performed in the paper to show the good performance of the method.     

The role of small‐scale fold and fault development in seismogenic zones: example of the western Huércal‐Overa Basin (eastern Betic Cordillera,Spain)

The NW–SE shortening between the African and the Eurasian plates is accommodated in the eastern Betic Cordillera along a broad area that includes large N‐vergent folds and kilometric NE–SW sinistral faults with related seismicity. We have selected the best exposed small‐scale tectonic structures located in the western Huércal‐Overa Basin (Betic Cordillera) to discuss the seismotectonic implications of such structures usually developed in seismogenic zones. Subvertical ESE–WNW pure dextral faults and E–W to ENE–ESW dextral‐reverse faults and folds deform the Quaternary sediments. The La Molata structure is the most impressive example, including dextral ESE–WNW Neogene faults, active southward‐dipping reverse faults and associated ENE–WSW folds. A molar M1 assigned to Mimomys savini allows for precise dating of the folded sediments (0.95–0.83 Ma). Strain rates calculated across this structure give ～0.006 mm a^?1 horizontal shortening from the Middle Pleistocene up until now. The widespread active deformations on small‐scale structures contribute to elastic energy dissipation around the large seismogenic zones of the eastern Betics, decreasing the seismic hazard of major fault zones. Copyright © 2009 John Wiley & Sons, Ltd.     

Multicollinearity in cross-sectional regressions

The paper examines robustness of results from cross-sectional regression paying attention to the impact of multicollinearity. It is well known that the reliability of estimators (least-squares or maximum-likelihood) gets worse as the linear relationships between the regressors become more acute. We resolve the discussion in a spatial context, looking closely into the behaviour shown, under several unfavourable conditions, by the most outstanding misspecification tests when collinear variables are added to the regression. A Monte Carlo simulation is performed. The conclusions point to the fact that these statistics react in different ways to the problems posed.     

Longitudinal and temporal patterns of benthic coarse particulate organic matter in the Agüera stream (northern Spain)

Benthic coarse particulate organic matter (CPOM) was studied between November 92 and December 93 at four sites along the longitudinal gradient of the Agüera stream system (Northern Spain). CPOM was sorted in four main categories: leaves (several species), fruits and seeds, twigs and debris. Headwater site showed higher densities of total CPOM, leaves and twigs than downstream reaches, but no regular longitudinal pattern of change was noticed. The ranges of mean CPOM standing stock at the sampling sites were 20.5–74.1 g AFDW m^–2 (site B), 9.9–47.7 g AFDW m^–2 (site 5), 4.3–21.4g AFDW m^–2 (site 7) and 9.8–37.9 g AFDW m^–2 (site 9). The particulate matter at downstream sites was in a more advanced stage of breakdown probably as a result of processing and transport from upstream reaches. Leaves species composition of benthic CPOM clearly reflected the type of riparian vegetation at each site. The timing of inputs and the hydrologic regime appeared to act together influencing temporal dynamics of benthic CPOM. A gradual temporal change in species composition of benthic leaf litter was observed under natural mature deciduous forest: first alder, later chestnut and finally oak.     

Mountain Front Development by Folding and Crustal Thickening in the Internal Zone of the Betic Cordillera-Alboran Sea Boundary

The boundary between the Alboran Sea and Betic Cordillera is a good example of a fold related mountain front in the Internal Zone of an alpine mountain range. Since the late Miocene, NNW-SSE convergence between the Eurasian and African plates has produced shortening and related orthogonal extension. To improve the characterisation of the geometry of the deep structure in the region and to establish the recent tectonic evolution of the mountain front, well logs and newly acquired geophysical data (multichannel reflection seismic and gravimetric surveys) have been interpreted and integrated with available surface data. The most marked tectonic structure corresponds to large antiforms and synforms of ENE-WSW trend which are related to mountain ranges and basins, respectively. The fold belt continues toward the northern continental shelf of the Alboran Sea. The fold vergence is generally northwards and its amplitude decreases progressively towards SSE, until disappearring in a sharp boundary where the reflectors are undeformed. The deep geometry suggests that fold growth started during upper Tortonian times and continued its activity up to Pliocene or even Quaternary times. The NNW-SSE compression produces crustal thickening and a regional and progressive southwards emersion. The location of main present-day deformation fronts in the Internal Zones contrasts with classical models where the deformation progresses towards the frontal part of External Zones of cordilleras. In addition, this fold-related deformation mountain front has features different from fault related fronts, as it does not show a sharp boundary, and folds that determine rectilinear mountain boundaries decrease progressively in amplitude or in wavelength up to undeformed areas.     

Un exemple de volcanisme calco-alcalin de type orogénique mis en place en contexte de rifting (Cambrien de l'oued Rhebar,Meseta occidentale,Maroc)

The Middle Cambrian calc-alkaline Oued Rhebar volcanic complex (western Meseta, Morocco) compares with rocks originated in orogenic contexts. The La/Nb ratios are relatively high (5.2), suggesting a lithospheric mantle origin. The La/Ta ratios, higher than 26, and the negative Nb anomaly indicate a lithospheric source contaminated by the continental crust. These rocks were generated in the Mesetian Mid-Cambrian rift and would have inherited their orogenic signature from the partial melting of a previously metasomatized mantle. To cite this article: H. El Hadi et al., C. R. Geoscience 338 (2006).     

Analysis of soil moisture dynamics beneath olive trees

Olive cultivation is a widespread land use in Mediterranean climates. The proper implementation of soil and water conservation practices in groves requires detailed knowledge of the governing hydrological processes. In this work topsoil moisture dynamics under wet and dry conditions and across a small catchment was investigated in the inter row (IR) and directly under the olive tree canopies (UC). We do this using a sensor network (11 stations) and a simple bucket model which was calibrated (June, 2011–2012) and validated (June, 2012–2013). During most of the year the normalized soil moisture contents (s) were greater in the IR than under UC, with an average normalized soil moisture difference of 0.12. The difference between UC and IR normalized soil moisture followed a seasonal pattern, reaching a maximum near 0.30 during spring. An analysis of the normalized soil moisture probability density functions (pdfs) was bimodal, showing characteristic dominant wet and dry soil moisture states, with the highest probability densities for the dry state. Overall the spatial variability of soil moisture was lower UC than in the IR. This was a result of the soil moisture buffering capacity of the canopy with respect to rainfall and evaporation, in addition to observed differences in soil properties. Hourly soil moisture data were successfully modelled (R² > 0.85), both UC and in the IR, yet with the inclusion of a simple formulation for canopy interception for the former. The results provide insight into how olive trees change hydrological processes in their neighbourhood. Copyright © 2016 John Wiley & Sons, Ltd.