An open ocean record of the Toarcian oceanic anoxic event

Oceanic anoxic events were time intervals in the Mesozoic characterized by widespread distribution of marine organic matter-rich sediments (black shales) and significant perturbations in the global carbon cycle. These perturbations are globally recorded in sediments as carbon isotope excursions irrespective of lithology and depositional environment. During the early Toarcian, black shales were deposited on the epi- and pericontinental shelves of Pangaea, and these sedimentary rocks are associated with a pronounced (ca. 7 ‰) negative (organic) carbon isotope excursion (CIE) which is thought to be the result of a major perturbation in the global carbon cycle. For this reason, the lower Toarcian is thought to represent an oceanic anoxic event (the T-OAE). If the T-OAE was indeed a global event, an isotopic expression of this event should be found beyond the epi- and pericontinental Pangaean localities. To address this issue, the carbon isotope composition of organic matter (δ13Corg of lower Toarcian organic matter-rich cherts from Japan, deposited in the open Panthalassa Ocean, was analysed. The results show the presence of a major (>6 ‰) negative excursion in δ13Corg that, based on radiolarian biostratigraphy, is a correlative of the lower Toarcian negative CIE known from Pangaean epi- and pericontinental strata. A smaller negative excursion in δ13Corg (ca. 2 ‰) is recognized lower in the studied succession. This excursion may, within the current biostratigraphic resolution, represent the excursion recorded in European epicontinental successions close to the Pliensbachian/Toarcian boundary. These results from the open ocean realm suggest, in conjunction with other previously published datasets, that these Early Jurassic carbon cycle perturbations affected the active global reservoirs of the exchangeable carbon cycle (deep marine, shallow marine, atmospheric)

Pulse Dynamics in a Chain of Granules With Friction

We study the dynamics of a pulse in a chain of granules with friction. We present theories for chains of cylindrical granules (Hertz potential with exponent $n=2$) and of granules with other geometries ($n>2$). Our results are supported via numerical simulations for cylindrical and for spherical granules ($n=5/2$).Comment: Submitted to PR

Objective assessment of the cryoprotective effects of dimethylformamide for freezing goat semen

AbstractThe aim of this work was to assess the cryoprotective effects of dimethylformamide (DMF) for freezing goat semen, using an objective analysis by computer-assisted sperm analysis (CASA). Twenty-one ejaculates (seven per animal) were collected from three stud bucks with the aid of an artificial vagina and immediately evaluated for gross and microscopic characteristics. The semen was diluted in two steps with a Tris–egg yolk extender containing 6% glycerol or 6% DMF, frozen in 0.50-mL straws, and stored in liquid nitrogen. Samples were accessed for sperm morphology, sperm membrane structural and functional integrity, and by CASA, immediately after thawing. There were differences (P<0.05) between glycerol and DMF with regard to subjective progressive motility (23.9±2.2% vs. 16.6±2.0%), objective progressive motility (3.5±0.4% vs. 1.8±0.3%), linearity (53.9±1.6% vs. 48.1±1.4%) and amplitude of lateral head (2.3±0.1 vs. 2.9±0.1mm), which confirmed the efficiency of glycerol. In conclusion, dimethylformamide could be used as an alternative cryoprotectant for goat semen freezing. However it was showed that no benefits were derived by using dimethylformamide to replace glycerol at an equal 6% concentration

Study of the effect of ozone in aqueous solution and chemical agents on strawberry’s safety (fragaria anannassa)

[PORT] O desenvolvimento de tecnologias inovadoras que promovam a segurança de frutos e vegetais, reduzindo o risco de doenças associadas a produtos contaminados, constitui uma preocupação actual. Os tratamentos térmicos, quando convenientemente aplicados, são eficientes na redução da carga microbiana dos frutos e vegetais. Contudo, a temperatura tem um impacto bastante negativo ao nível da textura dos alimentos. Como alternativa podem ser utilizados diversos agentes químicos na lavagem dos hortofrutícolas, tais como soluções de peróxido de hidrogénio e de cloro, de forma a garantir a sua segurança e maior retenção de qualidade. Mais recentemente, a utilização de ozono como agente desinfectante, quer em fase aquosa, quer em fase gasosa, tem vindo a ser objecto de estudo. Com este trabalho pretendeu-se estudar o efeito do ozono em solução aquosa, na redução de mesófilos totais em morango. Os resultados foram comparados com os obtidos por lavagens utilizando dois agentes químicos: soluções de peróxido de hidrogénio (1% e 5% m/m) e soluções de hipoclorito de sódio disponível na forma comercial de Amukina (11.5 g/L). Todos os tratamentos aplicados tiveram a duração de 2 minutos. Os tratamentos com ozono foram combinados com tratamentos térmicos (branqueamentos a 50 ou 55 ºC, durante 1 minuto). Os resultados mostraram que o tratamento não térmico mais eficaz na redução da flora mesófila, foi a lavagem com peróxido de hidrogénio a 5% (redução de cerca de 2 ciclos logarítmicos). Estes resultados não são significativamente diferentes dos resultados obtidos com lavagens com água ozonada (resultados confirmados por ANOVA e testes Post Hoc). O efeito dos tratamentos térmicos, a 50 e 55 ºC, não foi potenciado quando estes foram combinados com lavagens com ozono. Resultados semelhantes foram obtidos quando os tratamentos combinados foram aplicados por ordem alternada (i.e. branqueamento vs ozono ou ozono vs branqueamento). [ENG] The development of innovative technologies, aiming at reducing the risk of related food-borne diseases and thus promoting fruits and vegetables, is an actual concern. Thermal treatments, when conveniently applied, are efficient in microbial load reduction. However, temperature has a negative impact at food textural level. Alternatively, washings with solutions of several chemical agents, such as hydrogen peroxide or sodium hypochlorite, may be applied. More recently, the use of ozone as a disinfectant agent, both in aqueous or in gaseous phases, has been considered. The objective of this work was to study the effect of ozone in aqueous solution, on total mesophyles reduction in strawberries. Results were compared to the ones obtained with washings with two chemical agents: hydrogen peroxide solutions (1% and 5% w/w) and sodium hypochlorite solutions, commercially available as Amukina (11.5 g/L). All treatments were applied for 2 minutes. Ozone treatments were also combined with thermal processes (blanching at 50 or 55 ºC, for 1 minute). Results showed that washings with hydrogen peroxide solutions at 5% were the most efficient non-thermal treatments applied for mesophyles reduction in strawberries (approximately 2 log-cycles). These results were not significantly different from the ones obtained with ozonated-water washings (confirmed by ANOVA and Post Hoc tests). The thermal treatment effect, at 50 and 55 ºC, was not enhanced when combined with ozonatedwater washings. Similar results were obtained when the combined treatments were applied by alternated order (i.e. blanching vs ozono ou ozono vs blanching).Os autores agradecem o apoio financeiro ao Programa Operacional Agricultura e Desenvolvimento Rural – Projecto AGRO nº822 (Novas Tecnologias de Processamento de Hortofrutículas Congelados – EMERCON). Os autores Alexandre E.M.C., Santos-Pedro D.M. e Brandão T.R.S. agradecem ainda à Fundação para a Ciência e a Tecnologia (bolsas de investigação SFRH/BD/16042/2004, SFRH/BPD/9174/2002 e SFRH/BPD/11580/2002, respectivamente)

The microstructure and development of male genital organs of Spix's yellow-toothed cavy (Galea spixii) bred in captivity

O preá do semiárido nordestino (Galea spixii) é um roedor pertencente à família Caviidae. São encontrados nas regiões da Caatinga e do Cerrado Brasileiro e se reproduz ao longo do ano, apresentando um período de gestação de 48 dias e uma ninhada de 2 a 4 crias. O objetivo deste estudo foi caracterizar histologicamente os componentes estruturais dos órgãos genitais de preás machos relacionando com a evolução cronológica destes órgãos na espécie. Foram utilizados para análise animais ao nascimento e aos 15, 30, 45, 60, 75, 90, 105, 120 e aos 150 dias de idade. Fragmentos do epidídimo, ducto deferente, pênis e glândulas sexuais acessórias foram coletados, fixados e processados para descrição em microscopia de luz. O epidídimo apresentou epitélio colunar simples e em cada fase sexual notou-se diferença quanto ao tamanho do lúmen tubular e à presença de espermatozóides no lúmen aos 45 dias de idade. O epitélio do ducto deferente no preá mostrou-se pseudo-estratificado colunar com crescente presença de estereocilios com o avanço da idade. A glândula vesicular no preá apresentou uma mucosa com pregueamento variado, de acordo com a fase do desenvolvimento sexual. A próstata mostrou-se pouco desenvolvida, com lúmen pequeno nos preás ao nascimento e aos 15 dias de idade; aos 45 dias mostrou-se com um pregueamento do epitélio variável. Os órgãos genitais masculinos do preá passaram por transformações morfológicas no decorrer da idade e com o desenvolvimento sexual, isso colaborou para a determinação do início da fase da puberdade, que na espécie em estudo foi aos 45 dias de idade

Investigation of Changing Pore Topology and Porosity during Matrix Acidizing using Different Chelating Agents

Core flooding acidizing experiments on sandstone/carbonate formation are usually performed in the laboratory to observe different physical phenomena and to design acidizing stimulation jobs for the field. During the tests, some key parameters are analyzed such as pore volume required for breakthrough as well as pressure. Hydrochloric acid (HCl) is commonly used in the carbonate matrix acidizing while Mud acid (HF: HCl) is usually applied during the sandstone acidizing to remove damage around the well bore. However, many problems are associated with the application of these acids, such as fast reaction, corrosion and incompatibility of HCl with some minerals (illite). To overcome these problems, chelating agents (HEDTA, EDTA and GLDA) were used in this research. Colton tight sandstone and Guelph Dolomite core samples were used in this study. The experiments usually are defined in terms of porosity, permeability, dissolution and pore topology. Effluent samples were analyzed to determine dissolved iron, sodium, potassium, calcium and other positive ions using Inductively Coupled Plasma (ICP). Meanwhile Nuclear Magnetic Resonance (NMR) was employed to determine porosity and pore structure of the core sample. Core flood experiments on Berea sandstone cores and dolomite samples with dimensions of 1.5 in × 3 in were conducted at a flow rate of 1 cc/min under 150oF temperature. NMR and porosity analysis concluded that applied chemicals are effective in creating fresh pore spaces. ICP analysis concluded that HEDTA showed good ability to chelate calcium, sodium, magnesium, potassium and iron. It can be established from the analysis that HEDTA can increase more amount of permeability as compared to other chelates

Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

We present first measurements of the $\phi$-meson elliptic flow ($v_{2}(p_{T})$) and high statistics $p_{T}$ distributions for different centralities from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the $v_{2}$ of the $\phi$ meson is consistent with the trend observed for mesons. The ratio of the yields of the $\Omega$ to those of the $\phi$ as a function of transverse momentum is consistent with a model based on the recombination of thermal $s$ quarks up to $p_{T}\sim 4$ GeV/$c$, but disagrees at higher momenta. The nuclear modification factor ($R_{CP}$) of $\phi$ follows the trend observed in the $K^{0}_{S}$ mesons rather than in $\Lambda$ baryons, supporting baryon-meson scaling. Since $\phi$-mesons are made via coalescence of seemingly thermalized $s$ quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

Measurement of Transverse Single-Spin Asymmetries for Di-Jet Production in Proton-Proton Collisions at s=200\sqrt{s} = 200 GeV

We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity ($-1 \leq \eta \leq +2$) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering (SIDIS). We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in SIDIS and forward hadron production in pp collisions.Comment: 6 pages total, 1 Latex file, 3 PS files with figure

Plasma Wakefield Acceleration with a Modulated Proton Bunch

The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.Comment: 9 pages, 7 figure