118,147 research outputs found
Faunal and biogeographic analysis of Syllidae (Polychaeta) from Rovinj (Croatia, northern Adriatic Sea)
No full textThe study of hard-bottom Syllidae (Polychaeta) of the Rovinj area provides an updated measure of syllid species diversity in the northern Adriatic Sea. Faunal research in the coldest Mediterranean sectors may also help to address possible ecological and biogeographical consequences arising from climate change. Thirty-nine species were found, of which 13 are new for the northern Adriatic, increasing the species recorded from the area from 53 to 66. Some newly recorded species are dominant and typical of warmer areas. The lack of previous taxonomic updates is responsible for the high number of new findings. However, the northern Adriatic Sea is possibly undergoing long-term changes, with modifications of diversity due to the establishment of warm-water species. Syllid fauna of Sveti Ivan Island and its bioclimatic affinity are, in fact, unexpectedly more similar to the ones of some southern Mediterranean areas than to those traditionally reported for the northern Adriatic
Ecology and diversity of Mediterranean hard-bottom Syllidae (Annelida): A community-level approach
No full textThe Syllidae are geographically widespread polychaetes, particularly diverse and abundant on marine hard bottoms and in seagrass meadows. Hydrodynamics, habitat complexity and biological traits are hypothesized to influence syllid bathymetric distribution. Little is known about the consistency of, or variation in, horizontal distribution patterns with varying depth. I analyzed hard-bottom Syllidae at 2 depths (1.5 and 5 m) at the scale of 1000s of metres, located around the Torre Guaceto marine protected area (MPA) (SE Italy) in order to (1) quantify syllid diversity and abundance, (2) describe their distribution pattern and (3) identify potentially important factors influencing their distribution. The Syllidae were dominant and highly diverse, and new bio - geographic records were reported. Horizontal distribution patterns changed with depth, being more variable at 1.5 than 5 m. The presence of the MPA had little effect on alongshore variation in individual species abundance and assemblage structure. Contrary to expectations, there was no consistent relationship between Syllidae distribution and habitat-forming algal species. In contrast, syllid abundance varied with that of other invertebrates, suggesting that future research should focus on the role of interspecific interactions in syllid ecology. Syllidae are a highly diversified and widespread taxon that deserves special attention when analyzing biodiversity patterns of hard-bottom benthic communities. © Inter-Research 2012 · www.int-res.com
Agenda 21 i desenvolupament sostenible a Itàlia: estat de la qüestió
No full textIntervenció de Francesco Musco, Dr. Arquitecte de la Universitat IUAV de Venècia, en el marc de l' XI International Summer School on the Environment (ISSE 2011) sobre l'agenda 21 i el desenvolupament sostenible a Itàlia2196.mp4
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Planning, participation and sustainable development through an Agenda 21. The case of Polesine area
No full textSince 2001 the Province of Rovigo is very active to define environmental, social and economical development
policies, extremely suitable with a geographical area, the Polesine, bordered by the two greatest Italian
rivers: the Po and the Adige. Among the others actions to promote sustainability in the area we present
at Aalborg Conference three main projects:
1. Photovoltaic facilities
A wide project composed by three different actions to promote and use renewable energy: 3 photovoltaic
roofs, 1 photovoltaic façade of high architectonic quality, 280 photovoltaic street lamps.
2. Environmental Territorial Lab La.Terr.A.
The Lab is the information and education center for a sustainable society of Rovigo Province, managed
by the national association Legambiente
3. Agenda 21 Polesine
Agenda 21 Polesine as the participated decisional process to support local sustainability and an ecological
compatible development of territory
A new sponge-associated species, Syllis mayeri n. sp (Polychaeta : Syllidae), with a discussion on the status of S-armillaris (Muller, 1776)
No full textIn the framework of a study carried Out along the Belizean coasts, a new species of syllid. Syllis mayeri n. sp.. was found harboured by the sponge Ircinia strobilina. The description of this new taxon is given.. and compared to other similar congeneric species and to some Mediterranean material from the Southern Italian coast ascribed to S. armillaris. The new species is characterized by some stout compound chaetae with ypsiloid appearance, whose probable use for attaching to the host is hypothesized. Other diagnostic features are antennae, tentacular cirri and dorsal cirri of the anterior portion of the body that are longer than in similar, compared species. Moreover, the mid-body dorsal cirri are typically spindle-shaped. A discussion on the status of some sponge-associated taxa from tropical and Subtropical seas attributed to the so-called cosmopolitan S. armillaris is also give
A new species of sphaerosyllis (polychaeta, syllidae, exogoninae) from the coasts of italy and cyprus (eastern mediterranean sea)
No full textThe faunistic analysis of hard and soft benthic materials collected from the Marine Reserve of Porto Cesareo (Ionian Sea, Salento Peninsula, Italy) and the coast of northern Cyprus (Levant Sea) revealed a new species of Sphaerosyllis, S. boeroi sp. n. (Polychaeta, Syllidae, Exogoninae). This species is mainly characterized by having compound chaetae with discernable subdistal spine, a strong dorso-ventral gradation in size of blades throughout the body, elongated slender blades of superior compound chaetae on anterior and middle parapodia, parapodial glands with fibrillar material, and the distributional pattern of papillae on the body surface. Sphaerosyllis boeroi is described and compared to the other morphologically similar species, with emphasis on its ecological and reproductive patterns. © 2005 Taylor & Francis Group, LLC.Two of the Authors (L.M. and A.G.) wish to thank Drs Caterina Longo, Mariella Mercurio and Carlotta Nonnis Marzano from the University of Bari, and Dr. Cataldo Pierri from the University of Lecce for their help during the sampling phase. The other Author (M.E.Ç.) also thanks the crews and scientific personnel of the R/V K. PIRI REIS for their help in obtaining benthic samples, and TUBITAK (NATO-B1 Programme) for the financial support that enabled him to visit some research stations in Italy to make this collaboration possible. -
Simple Heuristics Yield Provable Algorithms for Masked Low-Rank Approximation
No full textIn the masked low-rank approximation problem, one is given data matrix A ∈ ℝ^{n × n} and binary mask matrix W ∈ {0,1}^{n × n}. The goal is to find a rank-k matrix L for which:
cost(L) := ∑_{i=1}^n ∑_{j=1}^n W_{i,j} ⋅ (A_{i,j} - L_{i,j})² ≤ OPT + ε ‖A‖_F²,
where OPT = min_{rank-k L̂} cost(L̂) and ε is a given error parameter. Depending on the choice of W, the above problem captures factor analysis, low-rank plus diagonal decomposition, robust PCA, low-rank matrix completion, low-rank plus block matrix approximation, low-rank recovery from monotone missing data, and a number of other important problems. Many of these problems are NP-hard, and while algorithms with provable guarantees are known in some cases, they either 1) run in time n^Ω(k²/ε) or 2) make strong assumptions, for example, that A is incoherent or that the entries in W are chosen independently and uniformly at random.
In this work, we show that a common polynomial time heuristic, which simply sets A to 0 where W is 0, and then finds a standard low-rank approximation, yields bicriteria approximation guarantees for this problem. In particular, for rank k' > k depending on the public coin partition number of W, the heuristic outputs rank-k' L with cost(L) ≤ OPT + ε ‖A‖_F². This partition number is in turn bounded by the randomized communication complexity of W, when interpreted as a two-player communication matrix. For many important cases, including all those listed above, this yields bicriteria approximation guarantees with rank k' = k ⋅ poly(log n/ε).
Beyond this result, we show that different notions of communication complexity yield bicriteria algorithms for natural variants of masked low-rank approximation. For example, multi-player number-in-hand communication complexity connects to masked tensor decomposition and non-deterministic communication complexity to masked Boolean low-rank factorization
Interactions of the C2 domain of human factor V with a model membrane
No full textActivated coagulation Factor V is an important cofactor of the coagulation cascade that catalyzes the formation, of the prothrombinase complex on. the surface of membranes rich in phosphatidyl-L-serine (PS). Here we report molecular dynamics simulations of the two crystallographic structures (the open and closed conformations) of domain C2 of coagulation Factor V (FaVC2). The calculations were performed in water (1.5 ns for each conformation) and in the presence of a neutral phospholipid bilayer model (POPE; 10 ns for each conformation) in order to describe the dynamics of the free (plasma circulating) and membrane bound forms of FaVC2. Water simulations confirmed the hypothesis that the plasma circulating form is in the closed conformation. In contrast, the membrane simulations showed that both conformations are energetically compatible with membrane binding. We have investigated the mechanism, the dynamics, and the energetics of the binding process. Our data are consistent with published estimates of the immersion depth of the aromatic residues (W26 and W27), and with mutagenesis studies involving specific residues located on the spikes at the bottom of the FaVC2 structure. Electrostatic interactions between the phospholipid head groups and hydrophilic residues at the bottom of the structure play a key role in the binding process by creating a large number of hydrogen bonds that anchor the protein to the membrane. The simulations identified a stable phospholipid binding pocket reminiscent of a previously suggested PS interaction site. Our structural data could contribute to the design of potential inhibitors able to disrupt membrane association
CITTÀ E CAMBIAMENTI CLIMATICI: IL RUOLO DEI GOVERNI LOCALI E LE STRATEGIE DELL'UNIONE EUROPEA
No full textCohabiting with litter: Fish and benthic assemblages in coastal habitats of a heavily urbanized area
No full textAnthropogenic litter negatively impacts the marine environment and threatens biodiversity. At the same time, it represents a suitable substrate for the settlement of sessile species, thus potentially altering composition and structure of soft bottom benthic assemblages. By using a Remotely Operated Vehicle (ROV), we hereby investigated patterns of abundance, distribution, and origin of benthic litter in three subtidal habitats of a heavily urbanized area and tested whether litter distribution related to patterns of fish and mega- and macro-benthic diversity. Litter accumulation mostly occurred on soft bottoms, while rocky substrata were the least affected, albeit being particularly threatened by sea-based pollution. As expected, the highest biodiversity was observed on rocky bottoms, hosting notable biogenic formations (Cladocora caespitosa, Leptogorgia sarmentosa) despite the area is historically affected by anthropogenic activities. No correlation was found between biota and marine litter, suggesting that litter does not apparently influence biodiversity and distribution of the investigated assemblages
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