5,871 research outputs found
Effect of Geometrical Imperfections on the Response of Dry-Joint Masonry Arches to Support Settlements
This paper aims to investigate the effects of geometrical imperfections on the response of a scaled dry-joint arch to the vertical displacement of one support. The arch behaviour was analysed in the large displacement regime using both physical and numerical modelling. The experimental tests were performed on 1:10 small-scale models made of bicomponent composite blocks with dry joints. In order to evaluate the geometrical accuracy of the blocks, two different sets of voussoirs were produced. The numerical simulations were carried out using a finite element (FE) micro-modelling approach, where the arch was modelled as an assembly of very stiff voussoirs connected by nonlinear interfaces. Particular attention was paid to the interface stiffness, which was set so as to tune the numerical model with the experimental evidence. Experimental and numerical results were then compared in terms of collapse mechanism, hinge configuration and ultimate displacement capacity. The imperfections of the physical models were found to significantly affect the arch response
Ab initio instanton rate theory made efficient using Gaussian process regression
Ab initio instanton rate theory is a computational method for rigorously
including tunnelling effects into calculations of chemical reaction rates based
on a potential-energy surface computed on the fly from electronic-structure
theory. This approach is necessary to extend conventional transition-state
theory into the deep-tunnelling regime, but is also more computationally
expensive as it requires many more ab initio calculations. We propose an
approach which uses Gaussian process regression to fit the potential-energy
surface locally around the dominant tunnelling pathway. The method can be
converged to give the same result as from an on-the-fly ab initio instanton
calculation but requires far fewer electronic-structure calculations. This
makes it a practical approach for obtaining accurate rate constants based on
high-level electronic-structure methods. We show fast convergence to reproduce
benchmark H + CH4 results and evaluate new low-temperature rates of H + C2H6 in
full dimensionality at a UCCSD(T)-F12b/cc-pVTZ-F12 level.Comment: 12 pages, 4 figures; submitted to Faraday Discussion: Quantum effects
in small molecular system
SARS-CoV-2 infection in a pediatric department in Milan : a logistic rather than a clinical emergency
Slow-Moving Landslide Damage Assessment of Historic Masonry Churches: Some Case-Studies in Italy
This paper presents a contribution for the damage assessment of historic masonry churches exposed to slow-moving landslides. In particular, the authors identified four global damage mechanisms, which are presented here by means of the critical damage assessment of four case studies located in the Liguria region (Italy) in areas affected by slow-moving landslides. For each church, a correlation between the damage patterns observed on-site and the ground movements induced by landslide phenomena was sought by means of visual inspections and crack interpretation. As a result, each damage mechanism was associated to a different pattern of ground movements produced by slow-moving landslides
Gene Flow in Medicago Through Somatic Hybridization
The objective of this research was the characterization at both molecular and phenotypic level of three somatic hybrid plants obtained by electrofusion of protoplasts of Medicago sativa with those of M.coerulea, M.falcata and M.arborea, three Medicago species in a different relation with alfalfa. Different kinds of rearrangements including the amplification of new spacer-length variants were detected at rDNA loci in the somatic hybrids. Analysis of field performances confirmed the suitability of these plants for breeding purposes
The importance of the period immediately preceding anthesis for grain weight determination in wheat
Although individual grain weight is an important source of variation for grain yield, there is still poor understanding of the causes determining final grain weight. Almost all studies conducted for understanding the determinants of grain weight have been focused on the post-anthesis period. However, there is important evidence that pre-anthesis conditions could also modify final grain weight. Three experiments including different sowing dates, genotypes and temperature regimes between booting and anthesis, were carried out in Argentina and Mexico to analyse the effect of temperature and associated traits during the pre- and post-anthesis periods on grain weight under field conditions. In these experiments final grain weight could not be explained by average or maximum temperature during the post-anthesis period. However, average temperature between booting and anthesis was closely related to the observed grain weight differences, probably as a consequence of the effects of this factor on carpel growth. Differences in grain weight between genotypes and grain position were successfully explained by differences in carpel weight at anthesis. These results suggest that our knowledge to determine grain weight could improve if the immediately pre-anthesis period conditions were taken into account.Fil: Calderini, Daniel Fernando. Universidad de Buenos Aires. Facultad de AgronomÃa. Departamento de Producción Vegetal; ArgentinaFil: Savin, Roxana. Universidad de Buenos Aires. Facultad de AgronomÃa. Departamento de Producción Vegetal; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Abeledo, Leonor Gabriela. Universidad de Buenos Aires. Facultad de AgronomÃa. Departamento de Producción Vegetal; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Reynolds, M. P.. Centro Internacional de Mejoramiento de MaÃz y Trigo; MéxicoFil: Slafer, Gustavo Ariel. Universidad de Buenos Aires. Facultad de AgronomÃa. Departamento de Producción Vegetal; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentin
CYP72A67 catalyses a key oxidative step in Medicago truncatula hemolytic saponin biosynthesis
In the Medicago genus, triterpenic saponins are bioactive secondary metabolites constitutively synthesized
in the aerial and subterranean parts of plants via the isoprenoid pathway. Exploitation of saponins
as pharmaceutics, agrochemicals and in the food and cosmetic industries has raised interest in identifying
the enzymes involved in their synthesis. We have identified a cytochrome P450 (CYP72A67) involved in
hemolytic sapogenin biosynthesis by a reverse genetic TILLING approach in a Medicago truncatula ethylmethanesulfonate
(EMS) mutagenized collection. Genetic and biochemical analyses, mutant complementation,
and expression of the gene in a microsome yeast system showed that CYP72A67 is responsible for
hydroxylation at the C-2 position downstreamof oleanolic acid synthesis. The affinity of CYP72A67 for substrates
with different substitutions at multiple carbon positions was investigated in the same in vitro yeast
system, and in relation to two other CYP450s (CYP72A68) responsible for the production of medicagenic
acid, the main sapogenin in M. truncatula leaves and roots. Full sib mutant and wild-type plants were
compared for their sapogenin profile, expression patterns of the genes involved in sapogenin synthesis,
and response to inoculation with Sinorhizobium meliloti. The results obtained allowed us to revise the
hemolytic sapogenin pathway in M. truncatula and contribute to highlighting the tissue specificities
(leaves/roots) of sapogenin synthesis
Publication and patent analysis of European researchers in the field of production technology and manufacturing systems
This paper develops a structured comparison among a sample of European researchers in the field of Production Technology and Manufacturing Systems, on the basis of scientific publications and patents. Researchers are evaluated and compared by a variegated set of indicators concerning (1) the output of individual researchers and (2) that of groups of researchers from the same country. While not claiming to be exhaustive, the results of this preliminary study provide a rough indication of the publishing and patenting activity of researchers in the field of interest, identifying (dis)similarities between different countries. Of particular interest is a proposal for aggregating analysis results by means of maps based on publication and patent indicators. A large amount of empirical data are presented and discusse
Characterization of prevalence and genetic subtypes of Blastocystis sp. in wild and domestic Suidae of central Italy aided by amplicon NGS
Blastocystis spp. is a common single-celled intestinal symbiont, comprising several genetic subtypes (ST) and trans-
missible by animal-to-animal, human-to-human, animal-to-human and, possibly, human-to-animal routes. This work
was designed to explore the presence of Blastocystis in sympatric domestic and wild suids and their ability to carry
zoonotic STs, in a condition of widespread opportunity to come in contact with the microorganism through their
shared water and food resources, and other carriers. We sampled 42 and 37 stool samples from wild boars and
domestic pigs, respectively. STs were first identified by PCR followed by Sanger sequencing. Sequences represented in
double-band PCR products or in Sanger chromatograms displaying multiple peaks, were resolved by next generation
sequencing (NGS). Twenty-six (61.9%) wild boar and 26 (70.2%) pig samples were PCR-positive, respectively. ST3,
ST5 and ST15 were found in 3.8%, 38.4% and 80.8% of the positive wild boars and 11.5%, 88.5%, 11.5% of the
positive pigs, respectively. ST1 was found only in pigs (3.8%). STs 5 and 15 were common in both groups of animals,
but in reversed proportions, suggesting preferential colonization. We found significantly different ST distributions
among wild boars and domestic pigs. This might indicate that lifestyle differences between the two populations
influence their risk for contracting certain subtypes, or that ST5 and ST15 can colonize preferentially wild or domestic
animals. Based on the STs described here, wild boars and domestic pigs can act as reservoirs with zoonotic potential.
The ability of suids to carry zoonotic STs appears to be higher when using NGS than Sanger sequencing, and resolution
of complex sequencing profiles is imperative before excluding the presence of STs of human concern
SuperB: a linear high-luminosity B Factory
This paper is based on the outcome of the activity that has taken place
during the recent workshop on "SuperB in Italy" held in Frascati on November
11-12, 2005. The workshop was opened by a theoretical introduction of Marco
Ciuchini and was structured in two working groups. One focused on the machine
and the other on the detector and experimental issues.
The present status on CP is mainly based on the results achieved by BaBar and
Belle. Estabilishment of the indirect CP violation in B sector in 2001 and of
the direct CP violation in 2004 thanks to the success of PEP-II and KEKB e+e-
asymmetric B Factories operating at the center of mass energy corresponding to
the mass of the Y(4s). With the two B Factories taking data, the Unitarity
Triangle is now beginning to be overconstrained by improving the measurements
of the sides and now also of the angles alpha, and gamma. We are also in
presence of the very intriguing results about the measurements of sin(2 beta)
in the time dependent analysis of decay channels via penguin loops, where b -->
s sbar s and b --> s dbar d. Tau physics, in particular LFV search, as well as
charm and ISR physics are important parts of the scientific program of a SuperB
Factory. The physics case together with possible scenarios for the high
luminosity SuperB Factory based on the concepts of the Linear Collider and the
related experimental issues are discussed.Comment: 22 pages, 22 figures, INFN Roadmap Repor
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