ALBERT

Description: For marine fish, the choice of the spawning location may be the only means to fulfil the dual needs of surviving from the egg to juvenile stage and dispersing across different habitats while minimizing predation and maximizing food intake. In this article, we review the factors that affect the choice of fish spawning habitats and propose a framework to distinguish between ecological and evolutionary constraints. We define the former as the boundaries for phenotypically plastic responses to environmental change, in this case the ability of specific genotypes to change their spawning habitat. Processes such as predation, starvation, or aberrant dispersal typically limit the amount of variability in spawning habitat that fish may undergo from 1 year to the next, and thus regulate the intensity of ecological constraints. Evolutionary constraints, on the other hand, refer to aspects of the genetic make-up that limit the rate and direction of adaptive genetic changes in a population across generations; that is, the potential for micro-evolutionary change. Thus, their intensity is inversely related to the level of genetic diversity associated with traits that regulate spawning and developmental phases. We argue that fisheries oceanographers are well aware of, and more deeply focused on, the former set of constraints, while evolutionary biologists are more deeply focused on the latter set of constraints. Our proposed framework merges these two viewpoints and provides new insight to study fish habitat selection and adaptability to environmental changes.

Description: We explore the assembly history of the M31 bulge within a projected major-axis radius of 180 arcsec (~680 pc) by studying its stellar populations in Hubble Space Telescope Wide Field Camera 3 and Advanced Camera for Surveys observations. Colours formed by comparing near-ultraviolet versus optical bands are found to become bluer with increasing major-axis radius, which is opposite to that predicted if the sole sources of near-ultraviolet light were old extreme horizontal branch stars with a negative radial gradient in metallicity. Spectral energy distribution fits require a metal-rich intermediate-age stellar population (300 Myr to 1 Gyr old, ~Z ) in addition to the dominant old population. The radial gradients in age and metallicity of the old stellar population are consistent with those in previous works. For the intermediate-age population, we find an increase in age with radius and a mass fraction that increases up to 2 per cent at 680 pc away from the centre. We exclude contamination from the M31 disc and/or halo as the main origin for this population. Our results thus suggest that intermediate-age stars exist beyond the central 5 arcsec (19 pc) of M31 and contribute ~1 per cent of the total stellar mass in the bulge. These stars could be related to the secular growth of the M31 bulge.

Description: SUMMARY We present new dedicated core surface field models spanning the decade from 2000.0 to 2010.0. These models, called gufm-sat , are based on CHAMP, Ørsted and SAC-C satellite observations along with annual differences of processed observatory monthly means. A spatial parametrization of spherical harmonics up to degree and order 24 and a temporal parametrization of sixth-order B-splines with 0.25 yr knot spacing is employed. Models were constructed by minimizing an absolute deviation measure of misfit along with measures of spatial and temporal complexity at the core surface. We investigate traditional quadratic or maximum entropy regularization in space, and second or third time derivative regularization in time. Entropy regularization allows the construction of models with approximately constant spectral slope at the core surface, avoiding both the divergence characteristic of the crustal field and the unrealistic rapid decay typical of quadratic regularization at degrees above 12. We describe in detail aspects of the models that are relevant to core dynamics. Secular variation and secular acceleration are found to be of lower amplitude under the Pacific hemisphere where the core field is weaker. Rapid field evolution is observed under the eastern Indian Ocean associated with the growth and drift of an intense low latitude flux patch. We also find that the present axial dipole decay arises from a combination of subtle changes in the southern hemisphere field morphology.

Description: Renewable energy has gained great attention and interest in recent years due to growing energy consumption and greater environmental concerns. Biomass is regarded as a promising candidate for replacing fossil-derived products, through either thermal, biological, or physical processes. This review focuses on thermal processing of biomass in molten salts for production of renewable fuels and chemicals, concepts based on dispersion of biomass or waste particles in a molten salt bath. Inorganic salts have very high heat capacities and good thermal stability at high temperatures. Some molten salts have catalytic properties, and in thermal processing of biomass, the product yields and compound compositions of products can be adjusted by varying compositions and amount of molten salts. In addition, molten salts will retain noxious contaminants, and it is thus possible to use difficult convertible- and/or contaminated biomass as feedstock.

Description: Dietz, R., Teilmann, J., Andersen S. M. Rigét, F., and Olsen, M. T. 2013. Movements and site fidelity of harbour seals ( Phoca vitulina ) in Kattegat, Denmark, with implications for the epidemiology of the phocine distemper virus. – ICES Journal of Marine Science, 70:186–195. Twenty-seven harbour seals were caught and tagged at the island of Anholt in central Kattegat, Denmark, the epicentre of the phocine distemper virus (PDV) outbreaks in 1988 and 2002 that killed 50–60% of the populations. The satellite tagging shows that harbour seals from Anholt moved widely across Kattegat with a maximum distance of 249 km from the tagging haul-out site. Overall, females travelled over a wider area compared with males [90% kernel home range (KHR) females, 5189 km 2 ; males, 3293 km 2 ). KHR calculated for yearlings (6414 km 2 ) is larger than for subadults (2534 km 2 ), which again is larger than for adult seals (1713 km 2 ), showing a strong site fidelity, indicating limited gene flow between haul-out sites. Distances moved and home range sizes increased across autumn, peaked in February–March, and decreased through spring. During the breeding season in spring, all seals were very stationary around Anholt. The onset of the PDV epizootics in 1988 and 2002 took place when the Anholt harbour seals congregate on the Island during April. Anholt seal were also documented to have contact with infected seal locations at Hesselø, Læsø, and the Swedish west coast, although this contact takes place during winter prior to the documented summer outbreaks.

Description: SUMMARY We present new dedicated core surface field models spanning the decade from 2000.0 to 2010.0. These models, called gufm-sat , are based on CHAMP, Ørsted and SAC-C satellite observations along with annual differences of processed observatory monthly means. A spatial parametrization of spherical harmonics up to degree and order 24 and a temporal parametrization of sixth-order B-splines with 0.25 yr knot spacing is employed. Models were constructed by minimizing an absolute deviation measure of misfit along with measures of spatial and temporal complexity at the core surface. We investigate traditional quadratic or maximum entropy regularization in space, and second or third time derivative regularization in time. Entropy regularization allows the construction of models with approximately constant spectral slope at the core surface, avoiding both the divergence characteristic of the crustal field and the unrealistic rapid decay typical of quadratic regularization at degrees above 12. We describe in detail aspects of the models that are relevant to core dynamics. Secular variation and secular acceleration are found to be of lower amplitude under the Pacific hemisphere where the core field is weaker. Rapid field evolution is observed under the eastern Indian Ocean associated with the growth and drift of an intense low latitude flux patch. We also find that the present axial dipole decay arises from a combination of subtle changes in the southern hemisphere field morphology.

Description: SUMMARY Simulations of earthquake rupture on the southern San Andreas Fault (SAF) reveal large amplifications in the San Gabriel and Los Angeles Basins (SGB and LAB) apparently associated with long-range path effects. Geometrically similar excitation patterns can be recognized repeatedly in different SAF simulations (e.g. Love wave-like energy with predominant period around 4 s, channelled southwestwardly from the SGB into LAB), yet the amplitudes with which these distinctive wavefield patterns are excited change, depending upon source details (slip distribution, direction and velocity of rupture). We describe a method for rapid calculation of the sensitivity of such predicted wavefield features to perturbations of the source kinematics, using a time-reversed (adjoint) wavefield simulation. The calculations are analogous to those done in adjoint tomography, and the same time-reversed calculation also yields path-sensitivity kernels that give further insight into the excitation mechanism. For rupture on the southernmost 300 km of SAF, LAB excitation is greatest for slip concentrated between the northern Coachella Valley and the transverse ranges, propagating to the NE and with rupture velocities between 3250 and 3500 m s –1 along that fault segment; that is, within or slightly above the velocity range (between Rayleigh and S velocities) that is energetically precluded in the limit of a sharp rupture front, highlighting the potential value of imposing physical constraints (such as from spontaneous rupture models) on source parametrizations. LAB excitation is weak for rupture to the SW and for ruptures in either direction located north of the transverse transverse ranges, whereas Ventura Basin (VTB) is preferentially excited by NE ruptures situated north of the transverse ranges. Path kernels show that LAB excitation is mediated by surface waves deflected by the velocity contrast along the southern margin of the transverse ranges, having most of their energy in basement rock until they impinge on the eastern edge of SGB, through which they are then funnelled into LAB. VTB amplification is enhanced by a similar waveguide effect.

Description: A basic challenge to successful management and conflict resolution is to correctly identify the spatial scale at which strategies for harvesting are developed. For commercially exploited marine fish, distributional boundaries of many stocks are based on the premise that productivity is similar at spatial scales that represent a small fraction of an individual's potential migration distance. Within such confined geographic regions, differences among individual life history traits—primary determinants of population productivity—are assumed to be negligible. The empirical basis for these assumptions bears re-examination for some widely distributed species, such as Atlantic cod ( Gadus morhua L.), for which there is evidence that life history structuring is evident at much finer scales than previously thought. Here, we focus on a unique system in the Norwegian Skagerrak, divided into inner and outer fjord habitats between which cod movement across distances of a few kilometres is limited and populations show signals of genetic differentiation. Based on back-calculated length-at-age data, cod in the inner fjord are systematically smaller at young ages (1–5 years) and are characterized by shorter asymptotic body lengths than cod in the outer fjord. Our work on growth and life history supports genetic analyses which indicate that productivity and resilience of widely distributed marine fish are likely to differ at considerably smaller spatial scales than those delineated by traditional stock management boundaries.

Description: We present sígame (SImulator of GAlaxy Millimetre/submillimetre Emission), a new numerical code designed to simulate the 12 CO rotational line spectrum of galaxies. Using sub-grid physics recipes to post-process the outputs of smoothed particle hydrodynamics (SPH) simulations, a molecular gas phase is condensed out of the hot and partly ionized SPH gas. The gas is subjected to far-UV radiation fields and cosmic ray ionization rates which are set to scale with the local star formation rate volume density. Level populations and radiative transport of the CO lines are solved with the 3D radiative transfer code lime . We have applied sígame to cosmological SPH simulations of three disc galaxies at z  = 2 with stellar masses in the range ~0.5–2  x  10 11  M and star formation rates ~40–140 M  yr –1 . Global CO luminosities and line ratios are in agreement with observations of disc galaxies at z  ~ 2 up to and including J = 3–2 but falling short of the few existing J =5–4 observations. The central 5 kpc regions of our galaxies have CO 3 – 2/1 – 0 and 7 – 6/1 – 0 brightness temperature ratios of ~0.55–0.65 and ~0.02–0.08, respectively, while further out in the disc the ratios drop to more quiescent values of ~0.5 and 〈0.01. Global CO-to-H 2 conversion (α CO ) factors are ${\simeq } 1.5\,{\rm {\rm {M}_{\odot }} \,pc^{-2}\,(K\,km\,s^{-1})^{-1}}$ , i.e. ~2–3 times below the typically adopted values for disc galaxies, and α CO increases with radius, in agreement with observations of nearby galaxies. Adopting a top-heavy Giant Molecular Cloud (GMC) mass spectrum does not significantly change the results. Steepening the GMC density profiles leads to higher global line ratios for J up ≥ 3 and CO-to-H 2 conversion factors [ ${\simeq } 3.6\,{\rm {\rm {M}_{\odot }} \,pc^{-2}\,(K\,km\,s^{-1})^{-1}}$ ].

Description: We present a new model of the radial (1-D) conductivity structure of Earth's mantle. This model is derived from more than 10 yr of magnetic measurements from the satellites Ørsted, CHAMP, SAC-C and the Swarm trio as well as the global network of geomagnetic observatories. After removal of core and crustal field as predicted by a recent field model, we fit the magnetic data with spherical harmonic coefficients describing ring current activity and associated induction effects and estimate global C -responses at periods between 1.5 and 150 d. The C -responses are corrected for 3-D effects due to induction in the oceans and inverted for a 1-D model of mantle conductivity using both probabilistic and deterministic methods. Very similar results are obtained, consisting of a highly resistive upper mantle, an increase in conductivity in and beneath the transition zone and a conductive lower mantle. Analysis of the Hessian of the cost function reveals that the data are most sensitive to structures at depths between 800 and 1200 km, in agreement with the results obtained from the probabilistic approach. Preliminary interpretation of the inverted conductivity structure based on laboratory-based conductivity profiles shows that the recovered structure in the lower mantle either requires higher temperatures or the presence of material of high conductivity related to ponding of carbonate melts below the transition zone.