1,729 research outputs found
One share - one vote : a european rule?
In this paper, I tackle the question whether one share - one vote should become a European law rule. I examine, first of all, the economic theory concerning one share - one vote and its optimality, and the law and economics literature on dual class recapitalizations and other deviations from one share - one vote. I also consider the agency costs of deviations from one share - one vote and examine whether they justify regulation. I subsequently analyze the rules implementing the one share - one vote standard in the US and Europe. In particular, I analyze the self-regulatory rules of US exchanges, the relevant provisions of the European Takeover Directive (including the well known break-through rule), and the European Court of Justice's position as to golden shares (which also are deviations from the one share - one vote standard). I conclude that one share - one vote is not justified by economic efficiency, as also confirmed by comparative law. Also the European breakthrough rule, which ultimately strikes down all deviations from one share - one vote, does not appear to be well grounded. Only transparency rules appear to be justified at EU level as disclosure of ownership and voting structures serves a pricing and governance function, while harmonisation of the relevant rules reduces transaction costs in integrated markets
From the double-stranded helix to the chiral nematic phase of B-DNA: a molecular model
B-DNA solutions of suitable concentration form left-handed chiral nematic
phases (cholesterics). Such phases have also been observed in solutions of
other stiff or semiflexible chiral polymers; magnitude and handedness of the
cholesteric pitch are uniquely related to the molecular features. In this work
we present a theoretical method and a numerical procedure which, starting from
the structure of polyelectrolytes, lead to the prediction of the cholesteric
pitch. Molecular expressions for the free energy of the system are obtained on
the basis of steric and electrostatic interactions between polymers; the former
are described in terms of excluded volume, while a mean field approximation is
used for the latter. Calculations have been performed for 130 bp fragments of
B-DNA. The theoretical predictions provide an explanation for the experimental
behavior, by showing the counteracting role played by shape and charge
chirality of the molecule.Comment: 42 pages, 6 figure
From rods to helices: evidence of a screw-like nematic phase
Evidence of a special chiral nematic phase is provided using numerical
simulation and Onsager theory for systems of hard helical particles. This phase
appears at the high density end of the nematic phase, when helices are well
aligned, and is characterized by the C symmetry axes of the helices
spiraling around the nematic director with periodicity equal to the particle
pitch. This coupling between translational and rotational degrees of freedom
allows a more efficient packing and hence an increase of translational entropy.
Suitable order parameters and correlation functions are introduced to identify
this screw-like phase, whose main features are then studied as a function of
radius and pitch of the helical particles. Our study highlights the physical
mechanism underlying a similar ordering observed in colloidal helical flagella
[E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and
raises the question of whether it could be observed in other helical particle
systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte
The Thermal Diffusivity of Biochar Coating Deposited on a Heat Exchanger â€
Biochar is a charcoal-like material obtained by burning organic wastes, coming from agricultural and forestry, in a controlled pyrolysis process. In this application, it is deposited on an aluminum foil of thickness 100 ÎĽm, which is used as a part of an heat exchanger. The thickness of the deposition of biochar on the aluminum foil ranges from 75 to 250 ÎĽm. The result coating is rough and, therefore, it is supposed to improve the heat exchange with the ambient environment, depending on the granulometry of the deposit. One key feature of the deposit is its thermal conductivity. In this work, it is determined by means of IR thermography used as a detector in a Laser Flash configuration. This allows us to evaluate the out-of-plane thermal diffusivity. Such measurements are complemented by density obtained by hydrostatic balance and specific heat by a differential scanning calorimeter
Performance Characterization of Image Feature Detectors in Relation to the Scene Content Utilizing a Large Image Database
Selecting the most suitable local invariant feature detector for a particular application has rendered the task of evaluating feature detectors a critical issue in vision research. Although the literature offers a variety of comparison works focusing on performance evaluation of image feature detectors under several types of image transformations, the influence of the scene content on the performance of local feature detectors has received little attention so far. This paper aims to bridge this gap with a new framework for determining the type of scenes which maximize and minimize the performance of detectors in terms of repeatability rate. The results are presented for several state-of-the-art feature detectors that have been obtained using a large image database of 20482 images under JPEG compression, uniform light and blur changes with 539 different scenes captured from real-world scenarios. These results provide new insights into the behavior of feature detectors
Expression of μ-protocadherin is negatively regulated by the activation of the β-catenin signaling pathway in normal and cancer colorectal enterocytes.
Mu-protocadherin (MUCDHL) is an adhesion molecule predominantly expressed by colorectal epithelial cells which is markedly downregulated upon malignant transformation. Notably, treatment of colorectal cancer (CRC) cells with mesalazine lead to increased expression of MUCDHL, and is associated with sequestration of β-catenin on the plasma membrane and inhibition of its transcriptional activity. To better characterize the causal relationship between β-catenin and MUCDHL expression, we performed various experiments in which CRC cell lines and normal colonic organoids were subjected to culture conditions inhibiting (FH535 treatment, transcription factor 7-like 2 siRNA inactivation, Wnt withdrawal) or stimulating (LiCl treatment) β-catenin activity. We show here that expression of MUCDHL is negatively regulated by functional activation of the β-catenin signaling pathway. This finding was observed in cell culture systems representing conditions of physiological stimulation and upon constitutive activation of β-catenin in CRC. The ability of MUCDHL to sequester and inhibit β-catenin appears to provide a positive feedback enforcing the effect of β-catenin inhibitors rather than serving as the primary mechanism responsible for β-catenin inhibition. Moreover, MUCDHL might have a role as biomarker in the development of CRC chemoprevention drugs endowed with β-catenin inhibitory activity
MAC Europe 1991 campaign: AIRSAR/AVIRIS data integration for agricultural test site classification
During summer 1991, multi-sensor data were acquired over the Italian test site 'Otrepo Pavese', an agricultural flat area in Northern Italy. This area has been the Telespazio pilot test site for experimental activities related to agriculture applications. The aim of the investigation described in the following paper is to assess the amount of information contained in the AIRSAR (Airborne Synthetic Aperture Radar) and AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) data, and to evaluate classification results obtained from each sensor data separately and from the combined dataset. All classifications are examined by means of the resulting confusion matrices and Khat coefficients. Improvements of the classification results obtained by using the integrated dataset are finally evaluated
Perenniality, more than genotypes, shapes biological and chemical rhizosphere composition of perennial wheat lines
Perennial grains provide various ecosystem services compared to the annual counterparts thanks to their extensive root system and permanent soil cover. However, little is known about the evolution and diversification of perennial grains rhizosphere and its ecological functions over time. In this study, a suite of -OMICSs - metagenomics, enzymomics, metabolomics and lipidomics - was used to compare the rhizosphere environment of four perennial wheat lines at the first and fourth year of growth in comparison with an annual durum wheat cultivar and the parental species Thinopyrum intermedium. We hypothesized that wheat perenniality has a greater role in shaping the rhizobiome composition, biomass, diversity, and activity than plant genotypes because perenniality affects the quality and quantity of C input – mainly root exudates – hence modulating the plant-microbes crosstalk. In support of this hypothesis, the continuous supply of sugars in the rhizosphere along the years created a favorable environment for microbial growth which is reflected in a higher microbial biomass and enzymatic activity. Moreover, modification in the rhizosphere metabolome and lipidome over the years led to changes in the microbial community composition favoring the coexistence of more diverse microbial taxa, increasing plant tolerance to biotic and abiotic stresses. Despite the dominance of the perenniality effect, our data underlined that the OK72 line rhizobiome distinguished from the others by the increase in abundance of Pseudomonas spp., most of which are known as potential beneficial microorganisms, identifying this line as a suitable candidate for the study and selection of new perennial wheat lines
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