Effects of different prey and rearing densities on growth and survival of octopus maya hatchlings

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Absorción y acumulación de vitelo externo dentro del saco vitelínico interno en embriones de Octopus vulgaris

Durante el desarrollo embrionario el órgano vitelínico mueve el aparato circulatorio del embrión y las reservas del vitelo externo al torrente sanguíneo (Boletzky, 2010). A partir del estadio XV de Nael (Nael, 1928) las reservas se acumulan en el saco vitelino intemo cuyo volumen aumenta hasta la eclosión (Boletzky, 2010). Tras ella, las paralarvas utilizan esas reservas como alimento endotrófico combinado con la alimentación exotrófica. la presencia de saco vitelino extemo indica una eclosión prematura y la pérdida de éste aumenta la tasa de mortalidad en las crías (Okubo, 1979). El objetivo de este trabajo lue mostrar la importancia del proceso de absorción y acumulación de vitelo externo dentro del saco vitelínico interno para el control de gasto energético, el crecimiento y perdida de peso. Para ello, se diseñó un experimento a dos temperaturas (14'C y 18'C) donde se incubaron dos puestas hasta la eclosión, midiendo la acumulación de vitelo en el saco interno. Tras la eclosión, las paralarvas se mantuvieron en inanición durante cinco días a las temperaturas de incubación y se controló el peso durante ese periodo. Se observaron dilerencias signilicativas (p<O,OS) en el momento de la eclosión, tanto en volumen como en peso de vitelo a 14ºC y a 18'C. la pérdida de peso en las paralarvas que permanecieron en inanición a 18'e lue más acentuada que en las paralarvas mantenidas a 14ºC. A bajas temperaturas el embrión acumula mayor cantidad de vitelo y tras la eclosión a temperaturas más altas disminuye el tiempo que tiene la paralarva para alimentarse exotróficamente

Efecto de la temperatura y el cuidado materno sobre el desarrollo embrionario del pulpo comun (Octopus vulgaris)

This work presents a study on the effects of two temperatures (14ºC and 18ºC) and incubation (artificial vs . female care) on the embryonic development of Octopus vulgaris . Results showed that type of incubation does not affect the embryonic development. For that reason data obtained from embryos incubated both artificial and by female were grouped. Temperature had a marked eff ect on embryonic development time of O. vulgari s . At 18ºC, embryonic development was of 40 days, while at 14ºC it was of 64 days. Temperature of 14 and 18°C were in the tolerance range of the species without affecting the morphological characteristics of hatchlings. Results showed that temperature modu lated in a different form the embryonic development, at least until stage XV where embryos maintained at 18°C showed values of eggs and embryo length lower than observed in embryos maintained at 14°C. t he fact that there were no differences between hatchli ngs maintained at both experimental temperatures demonstrates that O. vulgaris embryos can be favored if spawn occurs at relatively low but increasing temperatures, which contributes to a shorter planktonic life that will impact into the settle.En este trabajo se realizó el estudio sobre el desarrollo embrionario del pulpo común a 14ºC y a 18ºC y el efecto del cuidado materno. Los resultados muestran que la temperatura tiene un efecto marcado en el tiempo de desarrollo y que el cuidado mater no no afecta al desarrollo embrionario. A 18°C el tiempo de desarrollo fue de 40 días y a 14°C el tiempo de desarrollo fue de 64 dí as. A 18°C, se alcanzaron las estadios de Naef antes que a 14°C. Del mismo modo, el índice de desarrollo (DI) indica que caracterí sticas de diferenciación embrionaria fueron alcanzadas siempre antes a 18°C que a 14°C. Al final del desarrollo embrionario, no hubo diferencias en la longitud de l huevo, para los dos supuestos. Sin embargo, el aumento de longitud del huevo fue más evidente y visible cuando el embrión se comenzó a formar y con valores mayores a 14ºC que a 18ºC . L a longitud de embriones, la longitud del brazo, el diámetro del ojo, el peso del vitelo y el peso del huevo fue similar (p> 0,05) para ambas temperaturas, independientemente del cuidado materno, al final del período de desarrollo embrionario. Del mismo modo, no hubo diferencias en el peso ni en embriones ni en paralarvas reci én eclosionadas a las dos temperaturas ni con cuidado materno ni sin e

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

Search for supersymmetry at √S=8TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector

A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons (e or μ) with the same electric charge, or at least three isolated leptons. The search also utilises jets originating from b-quarks, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample corresponding to a total integrated luminosity of 20.3 fb−1 of √s = 8 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider in 2012. No deviation from the Standard Model expectation is observed. New or significantly improved exclusion limits are set on a wide variety of supersymmetric models in which the lightest squark can be of the first, second or third generations, and in which R-parity can be conserved or violated

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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Search for H→γγ produced in association with top quarks and constraints on the Yukawa coupling between the top quark and the Higgs boson using data taken at 7 TeV and 8 TeV with the ATLAS detector

A search is performed for Higgs bosons produced in association with top quarks using the diphoton decay mode of the Higgs boson. Selection requirements are optimized separately for leptonic and fully hadronic final states from the top quark decays. The dataset used corresponds to an integrated luminosity of 4.5 fb−14.5 fb−1 of proton–proton collisions at a center-of-mass energy of 7 TeV and 20.3 fb−1 at 8 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No significant excess over the background prediction is observed and upper limits are set on the tt¯H production cross section. The observed exclusion upper limit at 95% confidence level is 6.7 times the predicted Standard Model cross section value. In addition, limits are set on the strength of the Yukawa coupling between the top quark and the Higgs boson, taking into account the dependence of the tt¯H and tH cross sections as well as the H→γγ branching fraction on the Yukawa coupling. Lower and upper limits at 95% confidence level are set at −1.3 and +8.0 times the Yukawa coupling strength in the Standard Model

Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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