3,458 research outputs found
Origen y andanzas del término económico dita. Origin and vicissitudes of the business term dita
The etymology of the business term dita, which survives in America and in Andalusia, is still considered unresolved in the online version of the dictionary of
the Real Academia. Over a hundred years ago, Cuervo proposed an Italian origin, while Corominas later preferred a Catalan origin. In this article, I intend to show that the term indeed has Italian roots, but entered Spanish via Catalan. I will also argue that the hypotheses put forward by Cuervo and Corominas concerning the concrete word that served as a model were incorrect. The correct etymon is Italian detta, which in the Middle Ages referred to the words pronounced by a banker when transferring Money from one account to another
Sucrose- and H+-dependent charge movements associated with the gating of sucrose transporter ZmSUT1
Background: In contrast to man the majority of higher plants use sucrose as mobile carbohydrate. Accordingly proton-driven sucrose transporters are crucial for cell-to-cell and long-distance distribution within the plant body. Generally very negative plant membrane potentials and the ability to accumulate sucrose quantities of more than 1 M document that plants must have evolved transporters with unique structural and functional features.
Methodology/Principal Findings: To unravel the functional properties of one specific high capacity plasma membrane sucrose transporter in detail, we expressed the sucrose/H+ co-transporter from maize ZmSUT1 in Xenopus oocytes. Application of sucrose in an acidic pH environment elicited inward proton currents. Interestingly the sucrose-dependent H+ transport was associated with a decrease in membrane capacitance (Cm). In addition to sucrose Cm was modulated by the membrane potential and external protons. In order to explore the molecular mechanism underlying these Cm changes, presteady-state currents (Ipre) of ZmSUT1 transport were analyzed. Decay of Ipre could be best fitted by double exponentials. When plotted against the voltage the charge Q, associated to Ipre, was dependent on sucrose and protons. The mathematical derivative of the charge Q versus voltage was well in line with the observed Cm changes. Based on these parameters a turnover rate of 500 molecules sucrose/s was calculated. In contrast to gating currents of voltage dependent-potassium channels the analysis of ZmSUT1-derived presteady-state currents in the absence of sucrose (I = Q/Ï„) was sufficient to predict ZmSUT1 transport-associated currents.
Conclusions: Taken together our results indicate that in the absence of sucrose, ‘trapped’ protons move back and forth between an outer and an inner site within the transmembrane domains of ZmSUT1. This movement of protons in the electric field of the membrane gives rise to the presteady-state currents and in turn to Cm changes. Upon application of external sucrose, protons can pass the membrane turning presteady-state into transport currents
Modulatory Effect of Cattle on Risk for Lyme Disease
TOC Summary: Low-intensity cattle grazing limits Borrelia burgdorferi s.l., but not B. miyamotoi, in vector ticks
Co-feeding Transmission and Its Contribution to the Perpetuation of the Lyme Disease Spirochete Borrelia afzelii (In Reply to Randolph and Gern)
EtimologÃa lansquenetera de bombacho
El DCECH propone para bombacho una etimologÃa basada en una supuesta relación
metafórica con bomba ‘artefacto explosivo’. En la presenta nota, presento una explicación alternativa
basada en bomba ‘máquina hidráulica’. Defiendo la idea de que se trata de un calco del alemán Pumphose.
Esta etimologÃa se juzga también más plausible que la de Machado, quien relaciona bombacho con el
italiano bombace ‘algodón’
Derivados y compuestos cultos adjetivales en Juan de Mena
Obra completa disponible en: http://hdl.handle.net/2183/2796
Shifted linear systems in electromagnetics. Part I: Systems with identical right-hand sides
We consider the solution of multiply shifted linear systems for a single right-hand side. The coefficient matrix is symmetric, complex, and indefinite. The matrix is shifted by different multiples of the identity. Such problems arise in a number of applications, including the electromagnetic simulation in the development of microwave and mm-wave circuits and modules. The properties of microwave circuits can be described in terms of their scattering matrix which is extracted from the orthogonal decomposition of the electric field. We discretize the Maxwell's equations with orthogonal grids using the Finite Integration Technique (FIT). Some Krylov subspace methods have been used to solve multiply shifted systems for about the cost of solving just one system. We use the QMR method based on coupled two-term recurrences with polynomial preconditioning
- …