733 research outputs found
On some differential-geometric aspects of the Torelli map
In this note we survey recent results on the extrinsic geometry of the
Jacobian locus inside . We describe the second fundamental form
of the Torelli map as a multiplication map, recall the relation between totally
geodesic subvarieties and Hodge loci and survey various results related to
totally geodesic subvarieties and the Jacobian locus.Comment: To appear on Boll. UMI, special volume in memory of Paolo de
Bartolomei
A sensor fusion strategy based on a distributed optical sensing of airframe deformation applied to actuator load estimation
Real-time health monitoring of mechatronic onboard systems often involves model-based approaches comparing measured (physical) signals with numerical models or statistical data. This approach often requires the accurate measurement of specific physical quantities characterizing the state of the real system, the command inputs, and the various boundary conditions that can act as sources of disturbance. In this regard, the authors study sensor fusion techniques capable of integrating the information provided by a network of optical sensors based on Bragg gratings to reconstruct the signals acquired by one or more virtual sensors (separately or simultaneously). With an appropriate Fiber Bragg Gratings (FBGs) network, it is possible to measure directly (locally) several physical quantities (e.g. temperature, vibration, deformation, humidity, etc.), and, at the same time, use these data to estimate other effects that significantly influence the system behavior but which, for various reasons, are not directly measurable. In this case, such signals could be "virtually measured" by suitably designed and trained artificial neural networks (ANNs). The authors propose a specific sensing technology based on FBGs, combining suitable accuracy levels with minimal invasiveness, low complexity, and robustness to EM disturbances and harsh environmental conditions. The test case considered to illustrate the proposed methodology refers to a servomechanical application designed to monitor the health status in real-time of the flight control actuators using a model-based approach. Since the external aerodynamic loads acting on the system influence the operation of most of the actuators, their measurement would be helpful to accurately simulate the monitoring model's dynamic response. Therefore, the authors evaluate the proposed sensor fusion strategy effectiveness by using a distributed sensing of the airframe strain to infer the aerodynamic loads acting on the flight control actuator. Operationally speaking, a structural and an aerodynamic model are combined to generate a database used to train data-based surrogates correlating strain measurements to the corresponding actuator load
Karyological and molecular characterisation of subgenus Vicia (Fabaceae)
In the present report, we have analysed the subgenus Vicia by karyological and molecular approaches with the aim to clarify
the relationships among Vicia species included in this subgenus by previously evidenced morphological investigations.
Multivariate analysis using several karyomorphological parameters in addition to symmetry indices has allowed the
construction of a dendrogram of linkage distances very useful to compare and to include in a phylogenetic tree obtained by
internal transcribed spacer (ITS) rDNA sequences. Moreover, a separate analysis was performed combining our molecular
data on ITS sequences with those reported in the literature for the section Vicilla. Our analyses partly confirm the
monophyletic status of the various sections in which the subgenus Vicia has been divided, however questioning, in some
cases, the real need to maintain all the nine sections so far accepted and the placement of some individual species in the two
subgenera Vicia and Vicilla
Benefits of using digital thoracic drainage systems for post-operative treatment in pediatric populations: personal experience and review of literature
introduction: the digital chest drainage monitoring system (Medela Thopaz+), unlike analogical systems, reliably regulates the pressure applied to the patient's chest and digitally and silently monitors critical therapeutic indicators (volume of fluid and/or drained air). Its use in adulthood has been widely described, but there is still little experience in the pediatric field. the aim of this study is to test this new device in the pediatric population. materials and methods: we conducted a retrospective study of 160 patients undergoing chest surgery at our hospital. these patients were divided into 82 treated with the Thopaz system in the period from January 2021 to April 2023 and 78 in whom pleurevac, had been used in the time period from January 2020 to april 2023. results: the average age of patients was 10.45 years (range: 3.1–17.2) for the thopaz Group and 10.71 years for Pleurevac Group. The groups were homogeneus also by weight and type of intervention. the device was held in place for 10.64 days (mean) for thopaz group, compared to 16.87 days (mean) for pleurevac group (p < 0.05). The median number of postoperative x-rays before the closure of the chest tube was 4.29 in the digital drainage group compared to 8.41 in the traditional draining group (p < 0.05). conclusions: the digital chest monitoring device provides objective measurement, allows for rapid patient mobilization (with good pain control and increased compliance). in addition, the use of Thopaz in the paediatric population seems to be safe (there is no statistically significant difference in terms of complications such as prolonged air leaks and pneumothorax after the chest tube closure) and potentially beneficial
molecular and chromosomal characterization of repeated and single copy dna sequences in the genome of dasypyrum villosum
Restriction fragment length polymorphism of ribosomal DNA repeated unit and single-copy DNA fragments and chromosomal distribution of a highly repeated sequence, have been studied to assess molecular markers and the extent of their heterogeneity in Dasypyrum villosum. Substantial variation has been found for the length of the intergenic spacer of ribosomal genes clustered in different alleles at Nor- VI locus of heterozygous individuals, but not within the cluster of rDNA of homozygous individuals. After Southern blots and hybridization to an intergenic spacer probe, each cluster of rDNA was detected as a single band with at least four variants differing for the number of 130 bp subrepeats in the intergenic spacer. One recombinant plasmid contained a 2270 bp DNA insert from the D. villosum genome that upon Sph I restriction endonuclease digestion was cleaved in three 380 bp repeat elements and one 1090 bp fragment. When Southern blots of Sph 1 digested D. villosum DNAs of different genotypes were hybridized to the 32P-labelled 380 bp repeat, a distinct ladder consisting of multiples of a basic repeat unit of about 380 bp in length was revealed on autoradiograms. The in situ hybridization of the 3H-labelled 380 bp repeat element showed that one chromosome pair (7V) was not labelled. In the other pairs, silver grains remained clustered at or near the telomeres. Dot-blot hybridization analysis of DNAs from a range of diploid, tetraploid, and hexaploid Triticeae species indicated that the 380 bp repeated element was a specific feature of the D. villosum genome. Other cloned DNA sequences of D. villosum showed a large restriction length polymorphism and one was located on V chromosomes
Anabolic effects and inhibition of interleukin 6 production induced by neridronate on human osteoblasts
Bisphosphonates (BPs) are pharmacological compounds widely used in the treatment of a variety of bone-related diseases, particularly where the bone-turnover is skewed in favour of osteolysis. The mechanisms by which BPs reduce bone-resorption directly acting on osteoclasts (OCs) are now largely clarified even at molecular level. The researches concerning the BPs effects on osteoblasts (OBs) have instead shown variable results. Objectives: We have investigated the efficacy of neridronate (NER), an amino-BP, as anabolic agent on human OBs. Moreover, we have tried to verify if NER is able to negatively modulate the production of IL-6 on OBs stimulated or not by the pro-inflammatory cytokine Il-1b. Methods: We have tested if different concentrations of NER (from 10-11M to 10-3M), added to primary human OB cultures, could affect the cells number, the endogenous cellular alkaline phosphatase (ALP) activity, the collagen I (COLI) synthesis, the formation of mineralized nodules and the IL-6 production. Our experimental approach was performed testing a wide range of NER concentrations because, under physiological conditions, OBs seems to be exposed to variable and transient levels of the drug. Results: Our results show that NER doesn't negatively affect in vitro the viability, proliferation and cellular activity of human OBs, even after 20 days of exposure to concentrations ²10-5 M (therapeutic dose). In addition, NER seems to enhance the differentiation of cultured OBs in mature bone-forming cells. A maximum increase of COL-I synthesis (+25% after 4 days; p<0.05), ALP activity (+50% after 10 days; p<0.01) and mineralized nodules (+48% after 20 days; p<0.05) was observed in cultures treated with NER 10-8M. A maximal reduction of IL-6 secretion (-24% on IL-1b stimulated cultures and -29% on unstimulated cultures) was observed for NER 10-9 M. Conclusions: These results encourage the use of neridronate in therapy of demineralizing metabolic bone disorders
Shimura varieties in the Torelli locus via Galois coverings of elliptic curves
We study Shimura subvarieties of obtained from families of
Galois coverings where is a smooth complex
projective curve of genus and . We give the complete list
of all such families that satisfy a simple sufficient condition that ensures
that the closure of the image of the family via the Torelli map yields a
Shimura subvariety of for and for all and
for and . In a previous work of the first and second author
together with A. Ghigi [FGP] similar computations were done in the case .
Here we find 6 families of Galois coverings, all with and
and we show that these are the only families with satisfying this
sufficient condition. We show that among these examples two families yield new
Shimura subvarieties of , while the other examples arise from
certain Shimura subvarieties of already obtained as families of
Galois coverings of in [FGP]. Finally we prove that if a family
satisfies this sufficient condition with , then .Comment: 18 pages, to appear in Geometriae Dedicat
- …