On a class of rational and mixed soliton-rational solutions of Toda lattice

A class of rational solutions of Toda lattice satisfying certain Backlund transformations and a class of mixed rational-soliton solutions (quasisolitons) in wronskian formare obtained using the method of Ablowitz and Satsuma. Also an extended class of rational solutions are found using an appropriate recursion relation. They are also solutions of Boussinesq equation and it is conjectured that there is a larger class of common solutions of both equations.Comment: 10 pages, Late

Differences of interface and bulk transport properties in polymer field-effect devices

The influence of substrate treatment with self-assembled monolayers and thermal annealing was analysed by electrical and structural measurements on field-effect transistors (FETs) and metal-insulator-semiconductor (MIS) diodes using poly(3-hexylthiophene) (P3HT) as a semiconducting polymer and Si/SiO2 wafers as a substrate. It is found that surface treatment using silanising agents like hexamethyldisilazane (HMDS) and octadecyltrichlorosi-lane (OTS) can increase the field-effect mobility by up to a factor of 50, reaching values in saturation of more than 4E-2 cm^2/Vs at room temperature. While there is a clear correlation between the obtained field-effect mobility and the contact angle of water on the treated substrates, X-ray diffraction and capacitance measurements on MIS diodes show that structural and electrical properties in the bulk of the P3HT films are not influenced by the surface treatment. On the other hand, thermal annealing is found to cause an increase of grain size, bulk relaxation frequency and thereby of the mobility perpendicular to the SiO2/P3HT interface, but has very little influence on the field-effect mobility. Temperature dependent investigations on MIS diodes and FETs show that the transport perpendicular to the substrate plane is thermally activated and can be described by hopping in a Gaussian density of states, whereas the field-effect mobility in the substrate plane is almost temperature independent over a wide range. This investigations reveal significant differ-ences between interface and bulk transport properties in polymer field-effect devices.Comment: accepted at Organic electronic

Localised and nonlocalised structures in nonlinear lattices with fermions

We discuss the quasiclassical approximation for the equations of motions of a nonlinear chain of phonons and electrons having phonon mediated hopping. Describing the phonons and electrons as even and odd grassmannian functions and using the continuum limit we show that the equations of motions lead to a Zakharov-like system for bosonic and fermionic fields. Localised and nonlocalised solutions are discussed using the Hirota bilinear formalism. Nonlocalised solutions turn out to appear naturally for any choice of wave parameters. The bosonic localised solution has a fermionic dressing while the fermionic one is an oscillatory localised field. They appear only if some constraints on the dispersion are imposed. In this case the density of fermions is a strongly localised travelling wave. Also it is shown that in the multiple scales approach the emergent equation is linear. Only for the resonant case we get a nonlinear fermionic Yajima-Oikawa system. Physical implications are discussed.Comment: 7 pages, LaTeX, no figures. to appear in Europhysics Latter

Measurements of rainfall rate, drop size distribution, and variability at middle and higher latitudes: application to the combined DPR-GMI algorithm

The Global Precipitation Measurement mission is a major U.S.–Japan joint mission to understand the physics of the Earth’s global precipitation as a key component of its weather, climate, and hydrological systems. The core satellite carries a dual-precipitation radar and an advanced microwave imager which provide measurements to retrieve the drop size distribution (DSD) and rain rates using a Combined Radar-Radiometer Algorithm (CORRA). Our objective is to validate key assumptions and parameterizations in CORRA and enable improved estimation of precipitation products, especially in the middle-to-higher latitudes in both hemispheres. The DSD parameters and statistical relationships between DSD parameters and radar measurements are a central part of the rainfall retrieval algorithm, which is complicated by regimes where DSD measurements are abysmally sparse (over the open ocean). In view of this, we have assembled optical disdrometer datasets gathered by research vessels, ground stations, and aircrafts to simulate radar observables and validate the scattering lookup tables used in CORRA. The joint use of all DSD datasets spans a large range of drop concentrations and characteristic drop diameters. The scaling normalization of DSDs defines an intercept parameter NW, which normalizes the concentrations, and a scaling diameter Dm, which compresses or stretches the diameter coordinate axis. A major finding of this study is that a single relationship between NW and Dm, on average, unifies all datasets included, from stratocumulus to heavier rainfall regimes. A comparison with the NW–Dm relation used as a constraint in versions 6 and 7 of CORRA highlights the scope for improvement of rainfall retrievals for small drops (Dm lt; 1 mm) and large drops (Dm gt; 2 mm). The normalized specific attenuation–reflectivity relationships used in the combined algorithm are also found to match well the equivalent relationships derived using DSDs from the three datasets, suggesting that the currently assumed lookup tables are not a major source of uncertainty in the combined algorithm rainfall estimates

EFFECT OF LEVELLING ON THE ENERGY BALANCE OF MAIZE CROP FOR GRAINS

        Maize is recognized as a plant that greatly harnesses the allocated factors-the insurance with water and mineral fertilization-, bringing a substantial energy intake especially in the context of rational crop revolutions. From the point of view of fertilization, maize producing a large amount of plant substance at the surface unit, consumes high amounts of the main nutrients, which is a plant ,, voracious by excellence "and which responds promt to applied, but necessary water should be ensured at the appropriate time. The energy analysis in the case of maize for grains has shown high energy values produced in both cases concerning the location of culture-non-ivelate and even on ground level

The effects of IT investments and skilled labor on firms’ value added

Investments in information technologies (IT) and skilled labor are often highlighted as central for firms wishing to improve their performance. However, what mechanisms enable these investments to improve firm performance? The literature suggests two such channels: the production frontier of upgrading the input factors and the technical efficiency of exploiting the input factors in a more efficient way. We study these channels for increasing firms' value added in a stochastic frontier model. Notably, we find that investments in IT and skilled labor improve firms’ value added, but they do so through different channels. Multi-purpose hardware investments mainly improve efficiency in concert with other input factors, while investments in application-oriented software and skilled labor generally work by raising the production frontier itself

Amenajarea spaţiilor verzi urbane –impactul psihologic şi social asupra locuitorilor din Iaşi

It is well known in history that the rapid development of culture, civilization, technology and industry of the population from certain areas of the globe has been favored by a favorable environment,either geographically and climate or from the perspective of the absence of internal or external conflicts, by the presence on their territories of mineral or flora and fauna resources, or even their own human resource. Extrapolating the idea above, this paper seeks, at the smaller scale of a city nowadays, how the environmentally arranged landscape can beneficially influence the overall development of the urbanarea, but especially of its inhabitants, from the point of view of physically-psychological-sanogenic, but also socially and culturally, with examples from the city of Ias