4,752 research outputs found
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%
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
Global patterns of marine megafauna functional diversity
Marine megafauna (i.e. large-bodied marine animals with a body mass of >45 kg) perform important ecological roles in the oceans, yet their contributions to the stability and resilience of ecosystems are undermined by ongoing population decay due to intensified anthropogenic activities. Given the limited resources available to invest in conservation programs and the increasing numbers of threatened species due to fast-paced rate of biodiversity loss, recent efforts have been made into identifying species and areas of high conservation priority for protecting their ecological functionality. While species diversity has often been considered in guiding conservation actions, such recent interest in preserving species’ ecological contributions has advocated for integrating functional diversity in conservation planning. In this study, I assessed the global patterns of the functional and taxonomic diversity (i.e. functional richness and species richness, respectively) of marine megafauna to identify areas of exceptional functional importance. Accordingly, I identified the degree of congruence between locations of high species and functional richness by means of hotspots overlap analysis and applied a novel conservation index, FUSE (Functionally Unique, Specialized, and Endangered) to identify areas of conservation prioritization according to species’ contributions to functional diversity and their endangerment status. Hotspots of functional richness overlapped only marginally with those of species richness (by 34.5%). The South-West Pacific resulted as a major hotspot of exceptionally high functional richness, while the Caspian Sea and Gulf of Mexico were identified as areas of potential conservation priority harbouring species with high-ranking FUSE scores. Furthermore, the South-West Pacific was also an aggregation centre of high-ranking FUSE species. Overall, this study showed that setting conservation priority areas based on metrics of species diversity alone would be insufficient for safeguarding the ecological contributions of marine megafauna to the ecosystem, and that larger protection areas should be considered
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
Holocene fluvial and marine influences and settlement interactions in the lower Ribble Valley, Lancashire, U.K.
The evolution of the lower course and estuary of the river Ribble (Lancashire,
U.K.) during the Holocene is the object of study, along with the history of sediment fluxes in them and their influence on past human settlements.
Investigation of the valley floor geomorphology and terrace fill stratigraphy
and sedimentology, as well as palaeoecological analysis and a number of 14C
essays, allowed the reconstruction of Late Pleistocene and Holocene alluvial history and chronology of a reach at the transition point between fluvial and estuarine influences; the archaeological evidence is evaluated in this context.
Alluviation and incision cycles led to the formation of four river terraces. The oldest terrace, rich in coarse-grained materials, seems to be of Pleistocene age.
14C dating on the second terrace would point to an Earliest Holocene or Younger Dryas age; the fill, however, comprises abundant fine-grained overbank sediments. Large parts of the unit were reworked during a phase of
lateral channel activity that occurred prior to ca. 8900 cal BP; between then and ca. 6900 cal BP the river underwent meander cut-offs, after which limited lateral activity occurred. New alluviation occurred around 4700 cal BP, possibly related to the aggradation of the third terrace, though its fill is only certainly known, from archaeological evidence, to be of pre-Roman age. Channel size increase occurred by the time the terrace was deposited. The fill features abundant clayey sediments; it was incised at or after the end of the Roman
period. The last terrace was deposited in the late first millennium AD mainly as
overbank silts, and has since been incised again.
Fluvial response appears mainly related to climate changes, river activity corresponding to shifts to wetter, cooler climate. Human action likely enhanced fluvial response in the historical period, leading to post-Roman incision and deposition. There seems to be a good connection between sediment production
in the catchment and deposition downstream. Local factors also show a major importance in determining river response. Early Holocene fluvial history finds no match in other Northern English rivers; a different response to the same climate changes is apparent, possibly related to differences in sediment supply conditions.
No clear evidence is found supporting an influence of sea-level change on river
processes. On the other hand, it appears plausible river sediment input has a
driving influence in enhancing or causing minor regressions recorded on the estuary.
The conditions existing in Roman times could have allowed access from the sea to the Roman sites at the upper end of the Ribble estuary and by its North shore; a relative sea-level minimum could have caused a shift of focus in naval traffic from the former to the latter site
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
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