Inoculação de fungos micorrízicos arbusculares em porta-enxerto de pessegueiro cv Okinawa

O presente estudo teve por objetivo avaliar a influência da inoculação de fungos micorrízicos arbusculares (FMA) sobre o crescimento vegetativo, conteúdo de macronutrientes e de substâncias de reserva de plantas do porta-enxerto de pessegueiro cv Okinawa. O experimento foi realizado em telado, e o delineamento experimental utilizado foi o de blocos casualizados, com 20 plantas por parcela e quatro repetições. Foram testadas três espécies de FMA (Acaulospora sp., Glomus clarum e Glomus etunicatum) e um tratamento-testemunha, não-inoculado. A altura, o diâmetro, a área foliar, as biomassas fresca e seca, o conteúdo de macronutrientes e de substâncias de reserva foram avaliados aos 360 dias após a semeadura. Todas as plantas inoculadas com FMA apresentaram maior altura e diâmetro, quando comparadas à testemunha, sendo que Acaulospora sp. promoveu as melhores respostas. Glomus clarum e Glomus etunicatum induziram um crescimento intermediário às plantas. Os FMAs proporcionaram aumento na absorção de nitrogênio, fósforo e potássio, associados à maior altura, diâmetro do colo, área foliar, biomassa fresca e seca da parte aérea e seca das raízes, quando comparadas à testemunha. Todas as plantas inoculadas com FMA tiveram altas taxas de colonização, acima de 90%, sendo que Acaulospora sp. colonizou mais intensamente o sistema radicular das plantas.

The persistence of return on assets: differences between industries and differences between firms

This study offers a statistical analysis of the persistence of annual profits across a sample of firms from different European Union (EU) countries. To this end, a Bayesian dynamic model has been used which enables the annual behaviour of those profits to be broken down into a permanent structural component on the one hand and a transitory component on the other, while also distinguishing between general effects affecting the industry as a whole to which each firm belongs and specific effects affecting each firm in particular. This break down enables the relative importance of those fundamental components to be evaluated. The data analysed come from a sample of 23,293 firms in EU countries selected from the AMADEUS data-base. The period analysed ran from 1999 to 2007 and 21 sectors were analysed, chosen in such a way that there was a sufficiently large number of firms in each country*sector combination for the industry effects to be estimated accurately enough for meaningful comparisons to be made by sector and country. The analysis has been conducted by sector and by country from a Bayesian perspective, thus making the study more flexible and realistic since the estimates obtained do not depend on asymptotic results. In general terms, the study finds that, although the industry effects are significant, more important are the specific effects. That importance varies depending on the sector or the country in which the firm carries out its activity. The influence of firm effects accounts for more than 90% of total variation and display a significantly lower degree of persistence, with adjustment speeds oscillating around 51.1%. However, this pattern is not homogeneous but depends on the sector and country analysed. Industry effects have a more marginal importance, being significantly more persistent, with adjustment speeds oscillating around 10% with this degree of persistence being more homogeneous at both country and sector levels.

Ownership change and banking efficiency in the new EU members

The aim of this study is to analyze how European integration and, especially, changes in ownership, has affected banking efficiency in Central and Eastern European countries which have recently experimented this process more intensely. Using a stochastic frontier approach (SFA) applied to panel data, we have estimated bank efficiency levels in a sample of 189 banks from 12 countries during the period 2000 to 2008 and we have analyzed the influence of some bank characteristics on these efficiency levels. The results show that European integration has significantly improved the cost efficiency of banks in these countries but profit efficiency has significantly decreased. We have found very small differences between different ownership types and only a very small impact of foreign ownership on cost efficiency, showing that the entry of foreign ownership is not enough to explain the significant variations in banking efficiency after the accession.

Avantatges i conflictes de caràcter econòmic derivats de l'usdefruit en empreses familiars

L'usdefruit d'accions consisteix en l'exercici del dret real de gaudi de les rendes de títols constituïts com a inversions financeres. En l'empresa familiar, la propietat de l'acció pot estar en ocasions desdoblada i pertànyer en nua propietat a una persona i en usdefruit, a un altra. Però que succeeix quan l'empresa decideix no repartir dividends? El problema l'estudiem sobre el cas real de "Rosa Clara" en què un jutge condemna a pagar els dividends no distribuïts en els últims cinc anys d'usdefruit.

Ventajas y conflictos de caracter económico derivados del usufructo en empresas familiares

El usufructo de acciones consiste en el ejercicio del derecho real de disfrute de las rentas de títulos constituidos como inversiones financieras. En la empresa familiar, a veces la propiedad de la acción puede estar desdoblada y pertenecer en nuda propiedad a una persona y en usufructo, a otra. ¿Pero que sucede cuándo la empresa decide no dar dividendos? El problema lo estudiamos sobre el caso real de "Rosa Clara" en el que un juez condena a pagar los dividendos no distribuidos en los últimos cinco años de usufructo.

Anàlisi del finançament de l’empresa familiar enfront a la no familiar

Aquest treball presenta un anàlisi comparatiu de l’evolució de l’estructura econòmica i financera que presenten las empreses familiars (EF) i las empreses no familiars (EnF) des de l’any 2007 fins l’any 2011, amb una mostra d’empreses de Catalunya. La comparació d’aquests dos grups es basa amb dades dels estats financers extrets de la base de dades SABI. Aquesta mostra ha permès contrastar les hipòtesis establertes sobre el finançament de les mateixes i concloure que las EF presenten una estructura financera diferent a las EnF. Als seus balanços las EF reflecteixen un major nivell d’autofinançament que las EnF gràcies a la menor distribució de dividends. A més, s’observa que las EF es financen amb un cost de capital aliè inferior al de les EnF. No existeix correlació entre la rendibilitat econòmica i l’endeutament en las EF, és a dir, las EF mantenen un endeutament estable en el temps independentment de la seva rendibilitat, mentre que en el cas de les EnF si que hi ha correlació entre las dos variables, però aquesta és indirecta, de forma que las empreses més endeutades són les menys rentables, posant de manifest major dependència del capital aliè en les EnF que en les EF.

Análisis de la financiación de la empresa familiar frente a la no familiar

Este trabajo presenta un análisis comparativo de la evolución de la estructura económica y financiera que presentan las empresas familiares (EF) y las empresas no familiares (EnF) desde el año 2007 hasta el año 2011, en una muestra de empresas de Cataluña. La comparación de estos dos grupos se basa en datos de los estados financieros extraídos de la base de datos SABI. Esta muestra ha permitido contrastar las hipótesis establecidas sobre la financiación de las mismas y concluir que las EF presentan una estructura financiera diferente a las EnF. En sus balances las EF reflejan mayor nivel de autofinanciación que las EnF gracias a la menor distribución de dividendos. Además se observa que las EF se financian con un coste de capital ajeno inferior al de las EnF. No existe correlación entre rentabilidad económica y endeudamiento en las EF, es decir las EF mantienen un endeudamiento estable en el tiempo independientemente de su rentabilidad, mientras que en el caso de EnF si hay correlación entre las dos variables, pero esta es indirecta, de manera que las empresas más endeudadas son las menos rentables, poniendo de manifiesto mayor dependencia del capital ajeno en las EnF que en las EF.

Selection of internal control genes for real-time quantitative PCR in ovary and uterus of sows across pregnancy

Reproductive traits play a key role in pig production in order to reduce costs and increase economic returns. Among others, gene expression analyses represent a useful approach to study genetic mechanisms underlying reproductive traits in pigs. The application of reverse-transcription quantitative PCR requires the selection of appropriate reference genes, whose expression levels should not be affected by the experimental conditions, especially when comparing gene expression across different physiological stages.

Aplicación SaaS para la gestión de pequeñas empresas

Trabajo final de carrera en el área de ingeniería del software donde se realiza el análisis y diseño de una solución tecnológica que cubra las necesidades de gestión de una pequeña empresa, en concreto de un centro de belleza.

Electron tunneling in heavily In-doped polycrystalline CdS films

The electrical properties of heavily In‐doped polycrystalline CdS films have been studied as a function of the doping level. The films were prepared by vacuum coevaporation of CdS and In. Conductivity and Hall measurements were performed over the temperature range 77-400 K. The conductivity decreases weakly with the temperature and shows a tendency towards saturation at low temperatures. A simple relationship σ=σ0(1+βT2) is found in the low‐temperature range. The temperature dependence of the mobility is similar to that of the conductivity since the Hall coefficient is found to be a constant in the whole temperature range. We interpret the experimental results in terms of a modified version of grain‐boundary trapping Seto"s model, taking into account thermionic emission and tunneling of carriers through the potential barriers. The barriers are found to be high and narrow, and tunneling becomes the predominating transport mechanism.

In situ spectroellipsometric study of the nucleation and growth of amorphous silicon

A detailed in situ spectroellipsometric analysis of the nucleation and growth of hydrogenated amorphous silicon (a:Si:H) is presented. Photoelectronic quality a‐Si:H films are deposited by plasma‐enhanced chemical vapor deposition on smooth metal (NiCr alloy) and crystalline silicon (c‐Si) substrates. The deposition of a‐Si:H is analyzed from the first monolayer up to a final thickness of 1.2 μm. In order to perform an improved analysis, real time ellipsometric trajectories are recorded, using fixed preparation conditions, at various photon energies ranging from 2.2 to 3.6 eV. The advantage of using such a spectroscopic experimental procedure is underlined. New insights into the nucleation and growth mechanisms of a‐Si:H are obtained. The nucleation mechanism on metal and c‐Si substrates is very accurately described assuming a columnar microstructural development during the early stage of the growth. Then, as a consequence of the incomplete coalescence of the initial nuclei, a surface roughness at the 10-15 Å scale is identified during the further growth of a‐Si:H on both substrates. The bulk a‐Si:H grows homogeneously beneath the surface roughness. Finally, an increase of the surface roughness is evidenced during the long term growth of a‐Si:H. However, the nature of the substrate influenced the film growth. In particular, the film thickness involved in the nucleation‐coalescence phase is found lower in the case of c‐Si (67±8 Å) as compared to NiCr (118±22 Å). Likewise films deposited on c‐Si present a smaller surface roughness even if thick samples are considered (>1 μm). More generally, the present study illustrates the capability of in situ spectroellipsometry to precisely analyze fundamental processes in thin‐film growth, but also to monitor the preparation of complex structures on a few monolayers scale.