Forms of European Administrative Action

Chiti examines the various forms of European administration and their associated administrative law systems. Chiti recounts the history of administration and of administrative law in the European Community, examines the main types of administrative action in the Community, and highlights the novel elements and the shortcomings of European administrative law today

Analisi Fluodinamica di Reattori Bifase Gas-Liquido

The furnace treatment is an important step during molten aluminium production, by which the dissolved hydrogen and solid impurity particles were removed. Conventionally, a chlorine/inert gas mixture is used for this purpose. However the potential leakage of chlorine and chemical reaction produce hydrogen chloride considered to be dangerous to society and faces the restriction in the new clean air regulation. So, in order to meet the requirement for the furnace emission and improve efficiency, mechanical agitation through impeller was widely used. In this research, the homogenization behaviour of both lance bubbling and mechanical agitation through two different impellers has been investigated experimentally (power drawn, decolourusation, PIV) and numerically. At equivalent mean specific energy dissipation rates, maximum velocities are higher and mixing times are shorter with the impellers, without to cause surface gas entrainment, the latter being detrimental to fluxing. Two different impellers have been analysed because one is designed to resist at high temperature, STAS, and its material (graphite) does not allow a standard shape, so it was necessary to compare its performance with a standard impeller, 3PBT30. In conclusion, the STAS impeller has been considered a good solution for this kind of cleaning process, in fact, despite the strange shape (very thick blades), the impeller shows nice properties like a standard impeller, 3PBT30. Furthermore very interesting results have been obtained in mixing time using asymmetrical configurations, reducing the mixing time more than 20%

Complete element abundances of nine stars in the r-process galaxy Reticulum II

We present chemical abundances derived from high-resolution Magellan/MIKE spectra of the nine brightest known red giant members of the ultra-faint dwarf galaxy Reticulum II. These stars span the full metallicity range of Ret II (-3.5 < [Fe/H] < -2). Seven of the nine stars have extremely high levels of r-process material ([Eu/Fe]~1.7), in contrast to the extremely low neutron-capture element abundances found in every other ultra-faint dwarf galaxy studied to date. The other two stars are the most metal-poor stars in the system ([Fe/H] < -3), and they have neutron-capture element abundance limits similar to those in other ultra-faint dwarf galaxies. We confirm that the relative abundances of Sr, Y, and Zr in these stars are similar to those found in r-process halo stars but ~0.5 dex lower than the solar r-process pattern. If the universal r-process pattern extends to those elements, the stars in Ret II display the least contaminated known r-process pattern. The abundances of lighter elements up to the iron peak are otherwise similar to abundances of stars in the halo and in other ultra-faint dwarf galaxies. However, the scatter in abundance ratios is large enough to suggest that inhomogeneous metal mixing is required to explain the chemical evolution of this galaxy. The presence of low amounts of neutron-capture elements in other ultra-faint dwarf galaxies may imply the existence of additional r-process sites besides the source of r-process elements in Ret II. Galaxies like Ret II may be the original birth sites of r-process enhanced stars now found in the halo.Comment: 14 pages, 5 figures, 5 tables. Accepted to Ap

Sleep Period Optimization Model For Layered Video Service Delivery Over eMBMS Networks

Long Term Evolution-Advanced (LTE-A) and the evolved Multimedia Broadcast Multicast System (eMBMS) are the most promising technologies for the delivery of highly bandwidth demanding applications. In this paper we propose a green resource allocation strategy for the delivery of layered video streams to users with different propagation conditions. The goal of the proposed model is to minimize the user energy consumption. That goal is achieved by minimizing the time required by each user to receive the broadcast data via an efficient power transmission allocation model. A key point in our system model is that the reliability of layered video communications is ensured by means of the Random Linear Network Coding (RLNC) approach. Analytical results show that the proposed resource allocation model ensures the desired quality of service constraints, while the user energy footprint is significantly reduced.Comment: Proc. of IEEE ICC 2015, Selected Areas in Communications Symposium - Green Communications Track, to appea

In the aftermath of the crisis : the EU administrative system between impediments and momentum

The European responses to the financial and public debt crisis have triggered a process of administrative reorganization and growth within two fundamental sectors of the EU, the internal market of financial services and the EMU. This paper argues that the process of reorganization and growth of the EU administrative machinery within the single financial market and the EMU is characterized by a number of inherent tensions. Four of them are prominent and refer, respectively, to the powers conferred to the satellite administrative bodies established in order to tackle the crisis, to the jurisdictions of the new administrations, to the degree of centralization which is sought within the new mechanisms for the implementation of EU laws and policies, to the accountability mechanisms. When assessed in the light of their capability to improve the EU administrative capacities, such tensions appear to be deeply ambivalent. On the one hand, they might operate as «fault lines» of the whole EU administrative machinery, destabilizing its functioning in two important fields of EU action. On the other hand, by pointing to a host of unsolved issues in EU administrative law, they provide an opportunity for opening a genuine institutional and scientific discussion on the ways in which the EU administrative system should be adjusted or reformed

The regions of the sequence most exposed to the solvent within the amyloidogenic state of a protein initiate the aggregation process.

Formation of misfolded aggregates is an essential part of what proteins can do. The process of protein aggregation is central to many human diseases and any aggregating event needs to be prevented within a cell and in protein design. In order to aggregate, a protein needs to unfold its native state, at least partially. The conformational state that is prone to aggregate is difficult to study, due to its aggregating potential and heterogeneous nature. Here, we use a systematic approach of limited proteolysis, in combination with electrospray ionisation mass spectrometry, to investigate the regions that are most flexible and solvent-exposed within the native, ligand-bound and amyloidogenic states of muscle acylphosphatase (AcP), a protein previously shown to form amyloid fibrils in the presence of trifluoroethanol. Seven proteases with different degrees of specificity have been used for this purpose. Following exposure to the aggregating conditions, a number of sites along the sequence of AcP become susceptible to proteolytic digestion. The pattern of proteolytic cleavages obtained under these conditions is considerably different from that of the native and ligand-bound conformations and includes a portion within the N-terminal tail of the protein (residues 6-7), the region of the sequence 18-23 and the position 94 near the C terminus. There is a significant overlap between the regions of the sequence found to be solvent-exposed from the present study and those previously identified to be critical in the rate-determining steps of aggregation from protein engineering approaches. This indicates that a considerable degree of solvent exposure is a feature of the portions of a protein that initiate the process of aggregation

Exploring the mechanism of formation of native-like and precursor amyloid oligomers for the native acylphosphatase from Sulfolobus solfataricus

Over 40 human diseases are associated with the formation of well-defined proteinaceous fibrillar aggregates. Since the oligomers precursors to the fibrils are increasingly recognized to be the causative agents of such diseases, it is important to elucidate the mechanism of formation of these early species. The acylphosphatase from Sulfolobus solfataricus is an ideal system as it was found to form, under conditions in which it is initially native, two types of prefibrillar aggregates: (1) initial enzymatically active aggregates and (2) oligomers with characteristics reminiscent of amyloid protofibrils, with the latter originating from the structural reorganization of the initial assemblies. By studying a number of protein variants with a variety of biophysical techniques, we have identified the regions of the sequence and the driving forces that promote the first aggregation phase and show that the second phase consists in a cooperative conversion involving the entire globular fol

SD 1313-0019 -- Another second-generation star with [Fe/H] = -5.0, observed with the Magellan Telescope

We present a Magellan/MIKE high-resolution (R ~ 35,000) spectrum of the ancient star SD 1313-0019 which has an iron abundance of [Fe/H] = -5.0, paired with a carbon enhancement of [C/Fe] ~ 3.0. The star was initially identified by Allende Prieto et al. in the BOSS survey. Its medium-resolution spectrum suggested a higher metallicity of [Fe/H] = -4.3 due to the CaII K line blending with a CH feature which is a common issue related to the search for the most iron-poor stars. This star joins several other, similar stars with [Fe/H] < -5.0 that all display a combination of low iron and high carbon abundances. Other elemental abundances of SD 1313-0019 follow that of more metal-rich halo stars. From fitting the abundance pattern with yields of Population III supernova, we conclude that SD 1313-0019 had only one massive progenitor star with 20 - 30 M_sun that must have undergone a mixing and fallback episode. Overall, there are now five stars known with [Fe/H] < -5.0 (1D LTE abundances). This population of second-generation stars strongly suggests massive first stars that almost exclusively produced large amounts of carbon through stellar winds and/or their mixing and fallback supernova explosions. As a consequence, their natal clouds -- presumably some early minihalo structures -- contained ample amounts of carbon and oxygen that likely facilitated the formation of these first low-mass stars.Comment: 7 pages and 3 figures, accepted by ApJ

Co-populated Conformational Ensembles of β(2)-Microglobulin Uncovered Quantitatively by Electrospray Ionization Mass Spectrometry

Ordered assembly of monomeric human β(2)-microglobulin (β(2)m) into amyloid fibrils is associated with the disorder hemodialysis-related amyloidosis. Previously, we have shown that under acidic conditions (pH <5.0 at 37 °C), wild-type β(2)m assembles spontaneously into fibrils with different morphologies. Under these conditions, β(2)m populates a number of different conformational states in vitro. However, this equilibrium mixture of conformationally different species is difficult to resolve using ensemble techniques such as nuclear magnetic resonance or circular dichroism. Here we use electrospray ionization mass spectrometry to resolve different species of β(2)m populated between pH 6.0 and 2.0. We show that by linear deconvolution of the charge state distributions, the extent to which each conformational ensemble is populated throughout the pH range can be determined and quantified. Thus, at pH 3.6, conditions under which short fibrils are produced, the conformational ensemble is dominated by a charge state distribution centered on the 9+ ions. By contrast, under more acidic conditions (pH 2.6), where long straight fibrils are formed, the charge state distribution is dominated by the 10+ and 11+ ions. The data are reinforced by investigations on two variants of β(2)m (V9A and F30A) that have reduced stability to pH denaturation and show changes in the pH dependence of the charge state distribution that correlate with the decrease in stability measured by tryptophan fluorescence. The data highlight the potential of electrospray ionization mass spectrometry to resolve and quantify complex mixtures of different conformational species, one or more of which may be important in the formation of amyloid

Chemical Abundances of new member stars in the Tucana II dwarf galaxy

We present chemical abundance measurements for seven stars with metallicities ranging from [Fe/H] = $-$3.3 to [Fe/H] = $-$2.4 in the Tucana II ultra-faint dwarf galaxy (UFD), based on high-resolution spectra obtained with the MIKE spectrograph on the 6.5 m Magellan-Clay Telescope. For three stars, we present detailed chemical abundances for the first time. Of those, two stars are newly discovered members of Tucana II and were selected as probable members from deep narrow band photometry of the Tucana II UFD taken with the SkyMapper telescope. This result demonstrates the potential for photometrically identifying members of dwarf galaxy systems based on chemical composition. One new star was selected from the membership catalog of Walker et al. (2016). The other four stars in our sample have been re-analyzed, following additional observations. Overall, six stars have chemical abundances that are characteristic of the UFD stellar population. The seventh star shows chemical abundances that are discrepant from the other Tucana II members and an atypical, higher strontium abundance than what is expected for typical UFD stars. While unlikely, its strontium abundance raises the possibility that it may be a foreground metal-poor halo star with the same systemic velocity as Tucana II. If we were to exclude this star, Tucana II would satisfy the criteria to be a surviving first galaxy. Otherwise, this star implies that Tucana II has likely experienced somewhat extended chemical evolution.Comment: 20 pages, 6 figures, 5 tables; Accepted for publication in ApJ. Changes w.r.t. v1: corrected coordinates for TucII-078 in Table