21 research outputs found
Spectral Graph Analysis for Process Monitoring
Process monitoring is a fundamental task to support operator decisions under ab- normal situations. Most process monitoring approaches, such as Principal Components Analysis and Locality Preserving Projections, are based on dimensionality reduction. In this paper Spectral Graph Analysis Monitoring (SGAM) is introduced. SGAM is a new process monitoring technique that does not require dimensionality reduction techniques. The approach it is based on the spectral graph analysis theory. Firstly, a weighted graph representation of process measurements is developed. Secondly, the process behavior is parameterized by means of graph spectral features, in particular the graph algebraic connectivity and the graph spectral energy. The developed methodology has been illustrated in autocorrelated and non-linear synthetic cases, and applied to the well known Tennessee Eastman process benchmark with promising results.Fil: Musulin, Estanislao. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Rosario. Centro Internacional Franco Argentino de Ciencias de la InformaciĂłn y Sistemas; Argentin
Parasitism of aphids (Hemiptera: Aphididae) in relation to of alfalfa fields (Medicago sativa L.) caracteristics in Argentine Pampas
Alfalfa is a perennial crop and is one of the most relevant forage resources for cattle in the Argentine Pampas, with aphids (Hemiptera Aphididae) one of the main pest insects in alfalfa, being frequently attacked by a rich fauna of aphidiinae parasitoids (Hymenoptera: Braconidae). The aim of this study was to identify the possible field characteristics that influence the parasitism rates of aphids in alfalfa, in order to recommend simple methods of environmental manipulation to enhance the action of parasitoids. The abundance of aphids and their parasitism were estimated fortnightly, over a period of seven months in fourteen alfalfa fields located near the city of Rafaela, Santa Fe, through the collection of stem cuttings. The influence of field size, age of crop, and percentage of borders with spontaneous vegetation, on aphid abundance and their parasitism rates, were assessed through general lineal models with repeated measures. Greater aphid populations were observed in fields with a low percentage of natural borders, whereas the impact by parasitoids was higher in older crops and in those fields with a high percentage of natural borders. The relative importance of the characteristics of fields on parasitism of aphids is discussed, bearing in mind that conservation is the strategy of biological control recommended for developed countries given its low cost and potential sustainability.Fil: Zumoffen, Leticia. Instituto Nacional de TecnologĂa Agropecuaria. Centro Regional Santa Fe; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Salto, C.. Instituto Nacional de TecnologĂa Agropecuaria. Centro Regional Santa Fe; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Salvo, Silvia Adriana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; Argentin
In vitro incubation of human spermatozoa promotes reactive oxygen species generation and DNA fragmentation
The aim of this study was to investigate the oxidative process associated with sperm capacitation and its impact on DNA fragmentation and sperm function. Redox activity and lipid peroxidation were analysed in human spermatozoa after 3, 6 and 22h of incubation in Hams F10 medium plus bovine albumin at 37 degrees and 5% CO2 for capacitation. DNA status, tyrosine phosphorylation pattern and induced acrosome reaction were evaluated after capacitating conditions. At 22h of incubation, there was a significant (P<0.05) increase in oxygen-free radicals and lipid peroxidation, with no effect on sperm viability. There also was a significant (P<0.001) increase in fragmented DNA in capacitated spermatozoa compared to semen values with higher rates being found after the occurrence of the induced acrosome reaction. Protein tyrosine phosphorylation pattern confirms that capacitation took place in parallel with the occurrence of DNA fragmentation. These results indicate that when spermatozoa are incubated for several hours (22h), a common practice in assisted reproductive techniques, an increase in oxidative sperm metabolism and in the proportion of fragmentedDNA should be expected. However, there was no effect on any of the other functional parameters associated with sperm fertilising capacity47886186
Effects of ulipristal acetate on sperm DNA fragmentation during in vitro incubation
Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Objective Ulipristal acetate (UPA) acts as an emergency contraceptive by inhibiting ovulation. This study explores possible additional effects on the fragmentation of sperm DNA during in vitro incubation. Methods Motile spermatozoa from healthy donors were selected by swim-up and incubated under capacitating conditions in control medium or with UPA (1, 10, 100, 1,000 or 10,000 ng/ml). In some experiments, 200 mu M of H2O2 were added to induce oxidative stress. The sperm chromatin dispersion test was performed to analyse DNA integrity (400 cells; 1000X). Lipid peroxidation (thiobarbituric acid assay), induced-acrosome reaction (AR) and sperm vitality (Eosin Y) were also evaluated in spermatozoa exposed to UPA and/or H2O2. Results During sperm incubation, the percentage of fragmented DNA increased significantly, from 15.0 +/- 1.3 to 41.0 +/- 4.5% (p < 0.001). In the presence of UPA, DNA fragmentation decreased significantly (p < 0.05), in a dose-dependent manner. At 100 and 1000 ng/ml, UPA also counteracted the effect of H2O2 and prevented DNA fragmentation. No effect on sperm vitality, lipid peroxidation or induced-AR was found with any treatment. Conclusions During in vitro sperm capacitation DNA fragmentation increased but the latter was counteracted in the presence of UPA, which possibly acted as a scavenger of reactive oxygen species produced by spermatozoa.185355363Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)CNPq [573747/2008-3
Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina
Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Zoophthora radicans (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae) were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen) in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L.) aphids in Argentina
Potential plant–aphid–fungal associations aiding conservation biological control of cereal aphids in Argentina
Les premiers Anguilliformes : I. Révision des genres cénomaniens Anguillavus HAY, 1903 et Luenchelys nov. gen.
Insights into the Cenozoic geology of North Beirut (harbour area): biostratigraphy, sedimentology and structural history
The biostratigraphy and sedimentology of the outcrops and bedrock recently exposed in archaeological excavations around the harbour area of Beirut (~5 km²) unlock the geological and structural history of that area, which in turn are key to understanding the hydrocarbon and hydrogeological potential of the region. A key location (Site 2) of a studied outcrop section and newly uncovered bedrock is on the northern foothill cliff of East Beirut (Achrafieh). The outcrop section of carbonates is of Eocene beds overlain by conformable Miocene beds. The excavation of the slope bordering the outcrop uncovered a bedrock section of an early Pliocene shoreline of carbonate/siliciclastic sands at its base and topped by a beach-rock structure. The early Pliocene age of the shoreline section is dated by an assemblage of planktonic foraminifera that includes Sphaeroidinellopsis subdehiscens, Sphaeroidinella dehiscens and Orbulina universa. The Eocene carbonates of Site 2 extend the coverage of the previously reported Eocene outcrops in the harbour area. They form a parasequence of thin-bedded, chalky white limestones that includes the youngest fossil fish deposits in Lebanon ( Bregmaceros filamentosus). The deposits are dated as early Priabonian by their association with the planktonic foraminiferal assemblage of Porticulasphaera tropicalis, Globigerinatheka barri, Dentoglobigerina venezuelana, Globigerina praebulloides, Turborotalia centralis and Borelis sp. The Middle Miocene carbonates that conformably overlie the early Priabonian, parasequence include a planktonic foraminiferal assemblage of Globigerinoides trilobus, Orbulina universa and Borelis melo. Elsewhere, in the harbour area, the preserved Eocene limestones are also overlain by conformable Miocene carbonate parasequences of Langhian–Serravallian age. Younger argillaceous limestone beds of the Mio/Pliocene age occur in the eastern central part of the harbour area and enclose an assemblage of Truncorotalia crassaformis, Globorotalia inflata and Orbulina universa. The three markers of old and recently raised structural blocks in the harbour area are a Lutetian/Bartonian marine terrace in the south west corner, a lower Pliocene shoreline carbonate section in the north east side and a Holocene raised beach of marine conglomerates in the north east corner of the area. The locations of these paleo-shorelines, less than 2 km apart, indicate a progressive platform narrowing of North Beirut since the Paleogene. This study underpins the geological complexity of the region and contributes to understanding the underlying geology, which will be needed for future regional archaeological, hydrocarbon and hydrogeological exploration