725 research outputs found

    The Gribov problem in Noncommutative QED

    Get PDF
    It is shown that in the noncommutative version of QED (NCQED) Gribov copies induced by the noncommutativity of space-time appear in the Landau gauge. This is a genuine effect of noncommutative geometry which disappears when the noncommutative parameter vanishes.Comment: 19 pages, 3 figures. Published. The paper has been shortened and many references have been judged unnecessary or not suitable during the reviewing proces

    Spin-1 gravitational waves

    Get PDF
    Gravitational fields invariant for a 2-dimensional Lie algebra of Killing fields [ X,Y] =Y, with Y of light type, are analyzed. The conditions for them to represent gravitational waves are verified and the definition of energy and polarization is addressed; realistic generating sources are described.Comment: 18 pages, no figures. A section on possible sources has been added. Version accepted for publication in Int. J. Mod. Phys.

    Micro-CT studies on 3-D bioactive glass-ceramic scaffolds for bone regeneration

    Get PDF
    The aim of this study was the preparation and characterization of bioactive glass-ceramic scaffolds for bone tissue engineering. For this purpose, a glass belonging to the system SiO2-P2O5-CaO-MgO-Na2O-K2O (CEL2) was used. The sponge-replication method was adopted to prepare the scaffolds; specifically, a polymeric skeleton was impregnated with a slurry containing CEL2 powder, polyvinyl alcohol (PVA) as a binding agent and distilled water. The impregnated sponge was then thermally treated to remove the polymeric phase and to sinter the inorganic one. The obtained scaffolds possessed an open and interconnected porosity, analogous to cancellous bone texture, and with a mechanical strength above 2 MPa. Moreover, the scaffolds underwent partial bioresorption due to ion-leaching phe- nomena. This feature was investigated by X-ray computed microcomputed tomography (micro-CT). Micro-CT is a three-dimensional (3- D) radiographic imaging technique, able to achieve a spatial resolution close to 1 lm3. The use of synchrotron radiation allows the selected photon energy to be tuned to optimize the contrast among the different phases in the investigated samples. The 3-D scaffolds were soaked in a simulated body fluid (SBF) to study the formation of hydroxyapatite microcrystals on the scaffold struts and on the internal pore walls. The 3-D scaffolds were also soaked in a buffer solution (Tris-HCl) for different times to assess the scaffold bioresorp- tion according to the ISO standard. A gradual resorption of the pores walls was observed during the soakings both in SBF and in Tris- HC

    Metagenomic approach to identify the complex microbiota in Sicilian cheeses

    Get PDF
    The results obtained when identifying the microbiota in Sicilian cheeses were consistent for both taxonomic identification and abundance. Most of the genera detected in this work have often been described as a part of the microbiota of nonpasteurised milk.peer-reviewe

    LCA for a residential Italian multifamily building: a case study

    Get PDF
    The importance of the construction sector involves environmental, economic and social aspects. From an environmental point of view, the sector consumes about 60% of the mineral extraction from the lithosphere [1], and requires up to 40% of the total energy demand of an industrialized country [2]. Moreover, a huge amount of construction and demolition wastes are generated: 821 Mt/y only in Europe in 2012, i.e. 32.7% of the total amount of European waste [3-5]. An environmental friendly policy appears then necessary to improve the environmental performances of the sector. Please click Additional Files below to see the full abstract

    Deep sequencing targeted for strain identification of trypanosomatids

    Get PDF
    Trypanosomatidae is a group of kinetoplastid excavates distinguished by having only a single flagellum. All members are exclusively parasitic, found primarily in insects. The custom reads form Ilumina sequencing platform are aligned to reference genomes of different Leishmania species taken from TriTryp dabatase to be used for bioinformatics analysis.peer-reviewe

    Seroprevalence of and risk factors for Leishmania seropositivity in a sample population of Western Sicily (Italy)

    Get PDF
    Background: Leishmania is a vector-borne parasite responsible for significant morbidity and mortality worldwide. The aim of this study was to assess the prevalence of and risk factors for Leishmania infantum seropositivity in a sample of Sicilian population.Methods: A total of 260 subjects were interviewed using a standardized questionnaire and requested for an venous blood sample.Results: Overall, 36 subjects (13.8%) were seropositive against L. infantum with a statistically significant higher prevalence of positivity in older subjects (p=0.04). After adjustment for age, a higher risk for Leishmania seropositivity was found in subjects who had pets living outdoors and untreated with anti-pests, and in those who were current smokers (adj-OR = 2.95 and adj-OR = 3.11, respectively; p < 0.05).Conclusions: Our data confirm that Leishmania infections among Sicilian citizens can be considered relatively frequent, suggesting that a percentage of Leishmania seropositivity can be probably attributed to exposure to both old and new risk factors
    corecore