Sustainable Tuna Aquaculture – New Horizons

The SELFDOTT project has complied amply with the proposed objectives, substantiating the results of reproduction of Atlantic bluefin tuna in captivity obtained in the previous project REPRODOTT and laying down the bases for the production of fingerlings of this species and for the development of more efficient feeds respectful of the environment. Even if the advances achieved in the project can be classified as spectacular, there are still many aspects that must be improved, and, therefore, it is concluded that the large-scale commercial production of this species in a profitable manner is not yet developed sufficiently enough to fuel a new aquaculture industry.7 FP European Commissio

Model selection applied to reconstruction of the Primordial Power Spectrum

The preferred shape for the primordial spectrum of curvature perturbations is determined by performing a Bayesian model selection analysis of cosmological observations. We first reconstruct the spectrum modelled as piecewise linear in \log k between nodes in k-space whose amplitudes and positions are allowed to vary. The number of nodes together with their positions are chosen by the Bayesian evidence, so that we can both determine the complexity supported by the data and locate any features present in the spectrum. In addition to the node-based reconstruction, we consider a set of parameterised models for the primordial spectrum: the standard power-law parameterisation, the spectrum produced from the Lasenby & Doran (LD) model and a simple variant parameterisation. By comparing the Bayesian evidence for different classes of spectra, we find the power-law parameterisation is significantly disfavoured by current cosmological observations, which show a preference for the LD model.Comment: Minor changes to match version accepted by JCA

Spatial distribution of photoelectrons participating in formation of x-ray absorption spectra

Interpretation of x-ray absorption near-edge structure (XANES) experiments is often done via analyzing the role of particular atoms in the formation of specific peaks in the calculated spectrum. Typically, this is achieved by calculating the spectrum for a series of trial structures where various atoms are moved and/or removed. A more quantitative approach is presented here, based on comparing the probabilities that a XANES photoelectron of a given energy can be found near particular atoms. Such a photoelectron probability density can be consistently defined as a sum over squares of wave functions which describe participating photoelectron diffraction processes, weighted by their normalized cross sections. A fine structure in the energy dependence of these probabilities can be extracted and compared to XANES spectrum. As an illustration of this novel technique, we analyze the photoelectron probability density at the Ti K pre-edge of TiS2 and at the Ti K-edge of rutile TiO2.Comment: Journal abstract available on-line at http://link.aps.org/abstract/PRB/v65/e20511

The key neuroendocrine regulators of the onset of puberty in the Atlantic bluefin tuna (Thunnus thynnus)

Recently, significant progress on spawning induction in captive bluefin tuna (BFT, Thunnus thynnus), has been achieved providing the basis for the species' domestication. To further promote the development of a self- sustained BFT aquaculture, we investigated first sexual maturity in BFT reared from an immature stage in captivity. Accordingly, our major objectives were to evaluate: (i) maturational status of the brain-pituitary-gonadal (BPG) axis, and (ii) responsiveness of the BPG to exogenous hormones. Special emphasis was given to characterize the gonadotropins follicle stimulating hormone (FSH) and luteinizing hormone (LH) that act as central regulators of gonadal development and gamete maturation. The growth parameters recorded for the captive BFT juveniles are consistent with the length-weight relationship established for wild Mediterranean BFT stocks. The histological analyses of the gonads indicate advanced sexual maturation in BFT males compared to females, yet it is not yet clear whether this phenomenon typifies wild stocks or is induced due to the culture conditions. The hormone measurements show expression and accumulation of both gonadotropins in the pituitaries of immature and mature BFT. The pituitary LH content increased concomitantly with the age of the fish, exhibiting sex dimorphic patterns (i.e. 3-fold higher levels in females) in adult but not in juvenile BFT. The pituitary FSH levels, however, were elevated in 2Y immature males and in fully mature adults. Comparable to mammals, the intra-pituitary FSH/LH ratio was found to be higher (>1) in sexually immature than in maturing or pubertal BFT. Nevertheless, in the 3Y BFT females, which were all immature, the onset of puberty appears to require some other prerequisites, such as a rise in the LH storage above a minimal threshold. Our in vitro trials further demonstrated the capacity of rFSH and to a lesser extent that of rLH to stimulate cell proliferation in the immature ovarian and testicular fragments. Both rFSH and rLH have failed to stimulate steroidogenesis, yet pre-treatment with KiSS containing EVAc implants appeared to potentiate FSH-stimulated steroidogenesis in the immature testes. On the other hand, the expression levels of both the GtH-R and IGF I genes in the testicular fragments, derived from BFT juveniles and further exposed to the rLH treatment, showed dose-dependent pattern. Future studies testing the effects of captivity and hormone-based treatments on precocious maturity at relatively small body size are expected to facilitate the handling in confined environments, and to greatly improve the cost-efficiency of BFT farming.Postprin

Reconstruction of the Primordial Power Spectrum by Direct Inversion

We introduce a new method for reconstructing the primordial power spectrum, $P(k)$, directly from observations of the Cosmic Microwave Background (CMB). We employ Singular Value Decomposition (SVD) to invert the radiation perturbation transfer function. The degeneracy of the multipole $\ell$ to wavenumber $k$ linear mapping is thus reduced. This enables the inversion to be carried out at each point along a Monte Carlo Markov Chain (MCMC) exploration of the combined $P(k)$ and cosmological parameter space. We present best--fit $P(k)$ obtained with this method along with other cosmological parameters.Comment: 23 pages, 9 figure

Reproducción del atún rojo Thunnus thynnus en jaulas flotantes obtención de puestas masivas mediante implantes hormonales

In the frame of the SELFDOTT project (From capture based to SELF-sustained aquaculture and Domestication Of bluefin tuna, Thunnus thynnus) captive-reared Atlantic bluefin tuna (Thunnus thynnus) (n=15, estimated body weight=90 Kg) maintained for 3 years in captivity in El Gorguel (Cartagena, Spain) were administered a gonadotrophin releasing hormone agonist (GnRHa) implant underwater, during the natural spawning period for this species in the Mediterranean Sea (June). Beginning 48-72 h later, massive spawnings occurred everyday for 17 days, with a daily maximum fecundity of 34 million eggs. Egg collection was accomplished by placing a special curtain around the perimeter of the cage and at 6 m allowed the floating eggs to be maintained within the cage and be collected at night and sunrise with 500 ìm mesh size nets from the surface of the water.Proyecto SELFDOTT. UE

The PanCam Instrument for the ExoMars Rover

The scientific objectives of the ExoMars rover are designed to answer several key questions in the search for life on Mars. In particular, the unique subsurface drill will address some of these, such as the possible existence and stability of subsurface organics. PanCam will establish the surface geological and morphological context for the mission, working in collaboration with other context instruments. Here, we describe the PanCam scientific objectives in geology, atmospheric science, and 3-D vision. We discuss the design of PanCam, which includes a stereo pair of Wide Angle Cameras (WACs), each of which has an 11-position filter wheel and a High Resolution Camera (HRC) for high-resolution investigations of rock texture at a distance. The cameras and electronics are housed in an optical bench that provides the mechanical interface to the rover mast and a planetary protection barrier. The electronic interface is via the PanCam Interface Unit (PIU), and power conditioning is via a DC-DC converter. PanCam also includes a calibration target mounted on the rover deck for radiometric calibration, fiducial markers for geometric calibration, and a rover inspection mirror.publishersversionPeer reviewe

Reconstruction of the Primordial Power Spectrum using Temperature and Polarisation Data from Multiple Experiments

We develop a method to reconstruct the primordial power spectrum, P(k), using both temperature and polarisation data from the joint analysis of a number of Cosmic Microwave Background (CMB) observations. The method is an extension of the Richardson-Lucy algorithm, first applied in this context by Shafieloo & Souradeep. We show how the inclusion of polarisation measurements can decrease the uncertainty in the reconstructed power spectrum. In particular, the polarisation data can constrain oscillations in the spectrum more effectively than total intensity only measurements. We apply the estimator to a compilation of current CMB results. The reconstructed spectrum is consistent with the best-fit power spectrum although we find evidence for a `dip' in the power on scales k ~ 0.002 Mpc^-1. This feature appears to be associated with the WMAP power in the region 18 < l < 26 which is consistently below best--fit models. We also forecast the reconstruction for a simulated, Planck-like survey including sample variance limited polarisation data.Comment: 8 pages, 5 figures, comments welcom

Posibilidades de reproducción del atún rojo, Thunnus thynnus, en cautividad

This paper describes results achieved in a 3-year-long research project supported by the European Commission (EU) aimed at studying the feasibility to achieve reproduction of Bluefin tuna (BFT), Thunnus thynnus, in captivity. The project involves nine partners from seven Mediterranean countries. The overall objective of this project is to improve our understanding of the reproductive physiology of BFT as the basis to develop a suitable methodology for the control of its reproduction in captivity. Results have indicated that BFT reared in captivity are able to achieve maturation and spawn, naturally or hormonally induced, and consequently get larvae by in vitro fertilization. Thus, opening the possibility to an eco-friendly and economically sustainable production of BFT in the Mediterranean