Emerging risks of non-native species escapes from aquaculture: Call for policy improvements in China and other developing countries

Global aquaculture relies heavily on the farming of non-native aquatic species (hereafter, NAS). NAS escapes from aquaculture facilities can result in serious aquatic bio-invasions, which has been an important issue in the FAO Blue Growth Initiative. A regulatory quagmire regarding NAS farming and escapes, however, exists in most developing countries. We discuss aquaculture expansion and NAS escapes, illustrate emerging risks and propose recommendations for improved aquaculture management across developing countries and particularly for China. In China, 68 NAS are known to have successfully established feral populations in natural habitats due to recurrent leakages or escapes; among the 68 NAS, 52 represent risks to native aquatic ecosystems. In addition to affecting a country's own biodiversity and ecosystem functions, NAS escapees can also threaten the biosecurity of shared waters in neighbouring countries. Policy implications. Non-native aquatic species (NAS) escapes have already had adverse ecological effects in China and other developing countries. The importance of this problem, however, is not adequately recognized by current conservation policies in developing countries. To conserve biodiversity and to support the goal of FAO's sustainable aquaculture, developing countries should now take responsible actions to address NAS escapes through policy and management improvements. Specifically, these countries should pass comprehensive legislation, establish effective agencies and national standards and planning and enhance integrated research and education to deal with risk assessment, prevention, monitoring and control of NAS escapes. Given that China is the world's largest aquacultural producer, China can create a model for other developing countries that will increase the biosecurity and sustainability of global aquaculture

Structure formation in the presence of dark energy perturbations

We study non-linear structure formation in the presence of dark energy. The influence of dark energy on the growth of large-scale cosmological structures is exerted both through its background effect on the expansion rate, and through its perturbations as well. In order to compute the rate of formation of massive objects we employ the Spherical Collapse formalism, which we generalize to include fluids with pressure. We show that the resulting non-linear evolution equations are identical to the ones obtained in the Pseudo-Newtonian approach to cosmological perturbations, in the regime where an equation of state serves to describe both the background pressure relative to density, and the pressure perturbations relative to the density perturbations as well. We then consider a wide range of constant and time-dependent equations of state (including phantom models) parametrized in a standard way, and study their impact on the non-linear growth of structure. The main effect is the formation of dark energy structure associated with the dark matter halo: non-phantom equations of state induce the formation of a dark energy halo, damping the growth of structures; phantom models, on the other hand, generate dark energy voids, enhancing structure growth. Finally, we employ the Press-Schechter formalism to compute how dark energy affects the number of massive objects as a function of redshift.Comment: 21 pages, 8 figures. Matches published version, with caption of Fig. 6 correcte

Double butterfly spectrum for two interacting particles in the Harper model

We study the effect of interparticle interaction $U$ on the spectrum of the Harper model and show that it leads to a pure-point component arising from the multifractal spectrum of non interacting problem. Our numerical studies allow to understand the global structure of the spectrum. Analytical approach developed permits to understand the origin of localized states in the limit of strong interaction $U$ and fine spectral structure for small $U$.Comment: revtex, 4 pages, 5 figure

Adiabatic decaying vacuum model for the universe

We study a model that the entropy per particle in the universe is constant. The sources for the entropy are the particle creation and a lambda decaying term. We find exact solutions for the Einstein field equations and show the compatibilty of the model with respect to the age and the acceleration of the universe.Comment: 10 pages, 2 figure

Hemodynamics of the corpus luteum in mares during experimentally impaired luteogenesis and partial luteolysis

© 2017 The aim of the current project was to characterize the luteal vascularity and the plasma concentrations of progesterone (P4), prolactin (PRL) and 13,14-dihydro-15-keto-PGF2α (PGFM) in mares with luteal disturbances during early and mid-diestrus. In Experiment 1, twenty-one mares were treated with 2 mL of 0.9% NaCl, or 1 mg Dinoprost, or 10 mg Dinoprost on day two after ovulation (Control-D2, 1/10PGF-D2 and PGF-D2 groups, respectively; n = 7 mares/group). In Experiment 2, similar treatments were performed eight days post-ovulation using a different cohort of 21 mares (Control-D8, 1/10PGF-D8 and PGF-D8 groups, respectively; n = 7 mares/group). Blood samples were collected hourly and power-Doppler examinations of the corpus luteum (CL) were performed every 6 h from H0 (moment immediately before treatment) to H48. Data collection was also done once a day from D0 (day of ovulation) to D20. In Experiment 1, the PGF-D2 and 1/10PGF-D2 groups had lower increase of plasma concentration of P4 until H48 and reduced maximum P4 concentrations on D8-D11 than mares from the Control-D2 group. However, no differences among groups were detected for luteal vascularity during early and mid-diestrus. In Experiment 2, complete and partial luteolysis were detected in mares from the PGF-D8 and 1/10PGF-D8 groups, respectively. Luteal vascularity and plasma P4 concentrations differed among Control-D8, PGF-D8 and 1/10PGF-D8 groups on H48. Partially regressed CLs (1/10PGF-D8 group) generated more Doppler signals than completed regressed CLs (PGF-D8 group) between D10 and D13. In both experiments, a transient increase in PRL activity was observed in parallel to the PGFM pulse in mares receiving 1 or 10 mg Dinoprost. The use of prostaglandin on D2 at conventional or 1/10 of the dose impaired the luteal development in mares. Moreover, the low dose of prostaglandin lead to partial regression of mature CLs. The blood supply was reduced in partially regressed CLs, but not in CLs undergoing impaired luteogenesis

Classical and quantum dynamics of confined test particles in brane gravity

A model is constructed for the confinement of test particles moving on a brane. Within the classical framework of this theory, confining a test particle to the brane eliminates the effects of extra dimensions, rendering them undetectable. However, in the quantized version of the theory, the effects of the gauge fields and extrinsic curvature are pronounced and this might provide a hint for detecting them. As a consequence of confinement the mass of the test particle is shown to be quantized. The condition of stability against small perturbations along extra dimensions is also studied and its relation to dark matter is discussed.Comment: 15 pages, no figures, extended, references adde

Características quantitativas da carcaça de ovinos alimentados com dietas compostas por silagens com diferentes proporções de sorgo e girassol.

O objetivo deste experimento foi estudar características quantitativas da carcaça de ovinos terminados em confinamento, recebendo dietas compostas por silagens com diferentes proporções de sorgo e girassol. As dietas experimentais foram constituídas por 60% de volumoso e 40% de concentrado. Foram utilizados 30 cordeiros mestiços Santa Inês, machos não castrados, com média de peso inicial de 19,51 kg. Os animais foram abatidos após 56 dias de confinamento em baias individuais (4,0m2), alimentados com dietas contendo 0; 25; 50; 75 e 100% de silagem de girassol em substituição ao sorgo no volumoso. Não houve efeito significativo para as características de peso vivo ao abate (PVA), peso de corpo vazio (PCV), peso de carcaça quente (PCQ) e peso de carcaça fria (PCF), para os animais que receberam até 75% de silagem de girassol. As médias para as variáveis PVA, PCV, PCQ e PCF foram 33,59; 29,95; 16,14 e 14,83 kg, respectivamente. Os valores obtidos em relação aos rendimentos de carcaça quente e fria, não foram significativos para as dietas com até 100% de silagem de girassol, apresentando valores médios de 48,03 e 44,13%, respectivamente. O rendimento biológico médio foi de 54,24%. A silagem de girassol pode substituir a de sorgo em até 75% do volumoso, sem afetar de maneira significativa, as características quantitativas da carcaça de ovinos terminados em confinamento. Carcass quantitative characteristics of sheeps receiving diets containing different levels of sunflower silage in substitution of sorghum silage Abstract: The objective of this experiment was to study quantitative carcass traits of feedlot lambs fed diets with silages consisted of different proportions of sorghum and sunflower. The experimental diets consisted of 60% roughage and 40% concentrate. A total of 30 male lambs crossbred Santa Inês, non castrated, with initial average weight of 19.51 kg were evaluated. The animals were slaughtered after 56 days in feedlot in individual stalls (4,0m2), fed diets with 0; 25; 50; 75 and 100% of sunflower participation in silage mixed with sorghum. There was not an effect on the characteristics of live weight at slaughter (LWS), empty body weight (EBW), hot carcass weight (HCW) and cold carcass weight (CCW) for the animals that received silage with up to 75% of sunflower participation. The averages for the variables LWS, PCV, HCW and CCW were 33.59; 29.95; 16.14 and 14.83 kg, respectively. The values obtained for the hot and chilled yield were not significant for silages with up to 100% sunflower participation, with average values of 48.03 and 44.13% respectively. The biological average yield was 54.24%. Sunflower can substitute sorghum on silage composition up to 75%, without significantly affect the quantitative characteristics of feedlot lambs carcass

Deformed Gaussian Orthogonal Ensemble Analysis of the Interacting Boson Model

A Deformed Gaussian Orthogonal Ensemble (DGOE) which interpolates between the Gaussian Orthogonal Ensemble and a Poissonian Ensemble is constructed. This new ensemble is then applied to the analysis of the chaotic properties of the low lying collective states of nuclei described by the Interacting Boson Model (IBM). This model undergoes a transition order-chaos-order from the $SU(3)$ limit to the $O(6)$ limit. Our analysis shows that the quantum fluctuations of the IBM Hamiltonian, both of the spectrum and the eigenvectors, follow the expected behaviour predicted by the DGOE when one goes from one limit to the other.Comment: 10 pages, 4 figures (avaiable upon request), IFUSP/P-1086 Replaced version: in the previous version the name of one of the authors was omitte