846 research outputs found

    Atiya-Bott theory for orbifolds and Dedkind sums

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1994.Includes bibliographical references (leaf 17).by Ana M.L.G. Canas da Silva.M.S

    Post-Tracheal Extubation Pulmonary Oedema. Case Report

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    O edema agudo do pulmão pós-extubação traqueal é um acontecimento raro (≈ 0,1%)1. A etiologia é multifactorial, sendo a obstrução da via aérea superior o factor desencadeante principal. O esforço inspiratório contra a glote encerrada causa pressões intra torácicas muito negativas, que se transmitem ao interstício pulmonar, condicionando uma transudação de fluidos a partir dos vasos capilares pulmonares1-5. Relatamos um caso de edema agudo do pulmão pós-extubação num doente de quinze anos, operado no serviço de urgência por amputação traumática da perna esquerda. Revemos a fisiopatologia, o padrão radiológico, potenciais factores de risco e medidas preventivas desta complicação respiratória pós-anestésica

    Variación regional del coeficiente de atenuación de las ondas Rayleigh en el escudo Europeo

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    A partir del análisis del modo fundamental de las ondas Rayleigh generadas por tres terremotos situados en las Azores, Sicilia y el Mar Negro se obtiene la variación regional del coeficiente de atenuación en el escudo europeo para un intervalo de periodos de 15-80 s. El método de análisis ha consistido en comparar los espectros de amplitudes observados con los calculados teóricamente. Para el calculo de estos últimos se ha utilizado un nuevo método consistente en calcular la función global de la fuente a partir de un proceso de mínimos cuadrados.Los resultados son los siguientes. Para el terremoto de las Azoreslos valores del coeficiente de atenuación decrecen desde 0.00053 para el periodo de 15 s a un mínimo de 0.00027 a 35 S, aumentando ligeramente para periodos superiores. Para el terremoto del Mar Negro los valores del coeficiente de atenuación son aproximadamente los mismos hasta unos 40 S, decreciendo para periodos superiores hasta aproximadamente 0.00006. Para elterremoto de Sicilia los valores del coeficiente de atenuación incrementan desde 0.00013 a 15 s hasta 0.00052 a unos 40 s(valores anormalmente altos que pueden explicarse en parte como debido a que estas trayectorias atraviesan una region de flujo térmico muy elevado). Estos resultados, superiores a los obtenidos para la zona estable de Eurasia, muestran que pueden existir variaciones laterales importantes de Q entre la zona oriental y occidental del escudo europeo así como una zona de Q anormalmente baja en el Mar Mediterráneo al Norte de Sicilia

    Antioxidant activity and phenolic composition of wine spirit resulting from an alternative ageing technology using micro-oxygenation: a preliminary study

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    Aim: Alternative technologies for the aging of wine spirit, as for other spirit beverages, have been developed over the past decade in order to meet consumer and industry expectations of differentiation and sustainability. Physicochemical characterisation of the resulting products has been carried out, but no previous research has evaluated their antioxidant activity. This preliminary study examined the effect of an alternative ageing technology (micro-oxygenation combined with wood staves from chestnut or Limousin oak in 1000 L stainless steel tanks) in comparison with traditional technology (250 L new barrels) on the antioxidant activity and related phenolic composition of the wine spirit. Methods and results: The wine spirits resulting from both technologies were sampled after 8, 15, 30, 180 and 365 days of ageing. Samples taken were analysed using the DPPH method, HPLC and total phenolic index. Significantly higher antioxidant activity (50.43 % vs 36.42 % DPPH inhibition), together with greater enrichment in wood-derived compounds (51.79 vs 27.72 total phenolic index), was achieved in wine spirits aged using the alternative technology than in new barrels. Moreover, chestnut wood stood out from Limousin oak wood with higher promoted antioxidant activity (62.69 % vs 21.35 % DPPH inhibition), and higher phenolic index (49.03 vs 25.67). Significant correlations between the wine spirits’ antioxidant activity, total phenolic index, ellagic acid, gallic acid, vanillin and syringaldehyde concentrations were observed, particularly in those aged using the alternative technology. Conclusion: Micro-oxygenation combined with staves resulted in higher accumulation of bioactive compounds and antioxidant activity, thus increasing wine spirit quality and adding value to the product. Significance of the study: These preliminary results show that the characteristics acquired by the wine spirit, coupled with those revealed by previous research and the promotion of faster and cheaper ageing, make the alternative technology a promising option for the industryinfo:eu-repo/semantics/publishedVersio

    Fractal behaviour of the seismicity in the Southern Iberian Peninsula

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    The fractal behaviour of the seismicity in the Southern Iberian Peninsula is analysed by considering two different series of data: the distance and the elapsed time between consecutive seismic events recorded by the seismic network of the Andalusian Institute of Geophysics (AIG). The fractal analyses have been repeated by considering four threshold magnitudes of 2.5, 3.0, 3.5 and 4.0. The re-scaled analysis lets to determine if the seismicity shows strong randomness or if it is characterised by time-persistence and the cluster dimension indicates the degree of time and spatial clustering of the seismicity. Another analysis, based on the reconstruction theorem, permits to evaluate the minimum number of nonlinear equations describing the dynamical mechanism of the seismicity, its 'loss of memory', its chaotic character and the instability of a possible predicting algorithm. The results obtained depict some differences depending on distances or elapsed times and the different threshold levels of magnitude also lead to slightly different results. Additionally, only a part of the fractal tools, the re-scaled analysis, have been applied to five seismic crises in the same area

    Bioclimatology, structure, and conservation perspectives of Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana deciduous forests on Mediterranean bioclimate in the South-Central part of the Iberian Peninsula

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    The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercuspyrenaica, Aceropalus subsp. Granatensis, and Corylusavellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions.info:eu-repo/semantics/publishedVersio

    Alternative structures and bi-Hamiltonian systems on a Hilbert space

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    We discuss transformations generated by dynamical quantum systems which are bi-unitary, i.e. unitary with respect to a pair of Hermitian structures on an infinite-dimensional complex Hilbert space. We introduce the notion of Hermitian structures in generic relative position. We provide few necessary and sufficient conditions for two Hermitian structures to be in generic relative position to better illustrate the relevance of this notion. The group of bi-unitary transformations is considered in both the generic and non-generic case. Finally, we generalize the analysis to real Hilbert spaces and extend to infinite dimensions results already available in the framework of finite-dimensional linear bi-Hamiltonian systems.Comment: 11 page

    Greenhouse Evaluation of Air-Assisted Delivery Parameters for Mature Poinsettias

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    Understanding the performance characteristics of application equipment is important for helping make the most efficacious applications. While handguns making high volume applications are common in greenhouse production, it is difficult to achieve uniform distribution of product in a timely manner. Broadcast applications made using air-assistance can help aid canopy penetration and the volume of carrier required to make applications. The objectives of this research were to determine how air-assist sprayer application parameters influence spray deposits on the undersides of leaves in a mature poinsettia canopy. Bench-top trials were conducted using a motorized boom inside a greenhouse to treat a mature and dense poinsettia canopy. Sprayer treatments applied a tank mix of water and fluorescent tracer. Nylon screen targets were secured to the underside surfaces of leaves in the upper and lower elevation of target plants. A five-port, air-assist nozzle with flat fan nozzle tips was used to make the applications. Three air outlet speeds, two travel speeds, and three nozzle flow rates were evaluated. Each treatment was replicated three times. Spray deposits were highly variable. Upper elevation spray deposits were significantly greater than lower elevation deposits. Individually, higher air outlet speed (36.0 m s(-1)), slower travel speed (3.2 km h(-1)), and higher nozzle flow rate (1.17 L min(-1)) tended to produce higher sprayer deposits on the underside surfaces of leaves. The combination of travel speed and nozzle flow rate that produced the highest application rate (900 L ha(-1)) also produced the highest deposits. There was a 500% increase in underside leaf surface deposits in the lower canopy area for a corresponding 500% increase in application rate. However, the main effects produced no significant differences in spray deposits in the lower canopy area. Further improvements in directing sprays or providing canopy turbulence are necessary to improve deposition and management of insect pests feeding on the underside of poinsettia leaves

    The activity of cAMP-Phosphodiesterase 4D7 (PDE4D7) is regulated by protein kinase A-dependent phosphorylation within its unique N-terminus

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    The cyclic AMP phosphodiesterases type 4 (PDE4s) are expressed in a cell specific manner, with intracellular targeting directed by unique N-terminal anchor domains. All long form PDE4s are phosphorylated and activated by PKA phosphorylation within their upstream conserved region 1 (UCR1). Here, we identify and characterise a novel PKA site (serine 42) within the N-terminal region of PDE4D7, an isoform whose activity is known to be important in prostate cancer progression and ischemic stroke. In contrast to the UCR1 site, PKA phosphorylation of the PDE4D7 N-terminus appears to occur constitutively and inhibits PDE4 activity to allow cAMP signalling under basal conditions

    Multiplicity formulas for orbifolds

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1996.Includes bibliographical references (p. 46-47).by Ana M.L.G. Canas da Silva.Ph.D
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