669 research outputs found
Monte--Carlo Thermodynamic Bethe Ansatz
We introduce a Monte--Carlo simulation approach to thermodynamic Bethe ansatz
(TBA). We exemplify the method on one particle integrable models, which include
a free boson and a free fermions systems along with the scaling Lee--Yang model
(SLYM). It is confirmed that the central charges and energies are correct to a
very good precision, typically 0.1% or so. The advantage of the method is that
it enables the calculation of all the dimensions and even the particular
partition function.Comment: 22 pages. Added a footnote and realizations for the minimal models.
Fortran program, mont-s.f90, available from the source lin
Excited State Destri - De Vega Equation for Sine-Gordon and Restricted Sine-Gordon Models
We derive a generalization of the Destri - De Vega equation governing the
scaling functions of some excited states in the Sine-Gordon theory. In
particular configurations with an even number of holes and no strings are
analyzed and their UV limits found to match some of the conformal dimensions of
the corresponding compactified massless free boson. Quantum group reduction
allows to interpret some of our results as scaling functions of excited states
of Restricted Sine-Gordon theory, i.e. minimal models perturbed by phi_13 in
their massive regime. In particular we are able to reconstruct the scaling
functions of the off-critical deformations of all the scalar primary states on
the diagonal of the Kac-table.Comment: Latex, 12 page
Nonlinear integral equations for finite volume excited state energies of the O(3) and O(4) nonlinear sigma-models
We propose nonlinear integral equations for the finite volume one-particle
energies in the O(3) and O(4) nonlinear sigma-models. The equations are written
in terms of a finite number of components and are therefore easier to solve
numerically than the infinite component excited state TBA equations proposed
earlier. Results of numerical calculations based on the nonlinear integral
equations and the excited state TBA equations agree within numerical precision.Comment: numerical results adde
Immune response in peripheral axons delays disease progression in SOD1(G93A) mice.
BACKGROUND: Increasing evidence suggests that the immune system has a beneficial role in the progression of amyotrophic lateral sclerosis (ALS) although the mechanism remains unclear. Recently, we demonstrated that motor neurons (MNs) of C57SOD1(G93A) mice with slow disease progression activate molecules classically involved in the cross-talk with the immune system. This happens a lot less in 129SvSOD1(G93A) mice which, while expressing the same amount of transgene, had faster disease progression and earlier axonal damage. The present study investigated whether and how the immune response is involved in the preservation of motor axons in the mouse model of familial ALS with a more benign disease course. METHODS: First, the extent of axonal damage, Schwann cell proliferation, and neuromuscular junction (NMJ) denervation were compared between the two ALS mouse models at the disease onset. Then, we compared the expression levels of different immune molecules, the morphology of myelin sheaths, and the presence of blood-derived immune cell infiltrates in the sciatic nerve of the two SOD1G93A mouse strains using immunohistochemical, immunoblot, quantitative reverse transcription PCR, and rotating-polarization Coherent Anti-Stokes Raman Scattering techniques. RESULTS: Muscle denervation, axonal dysregulation, and myelin disruption together with reduced Schwann cell proliferation are prominent in 129SvSOD1(G93A) compared to C57SOD1(G93A) mice at the disease onset, and this correlates with a faster disease progression in the first strain. On the contrary, a striking increase of immune molecules such as CCL2, MHCI, and C3 was seen in sciatic nerves of slow progressor C57SOD1(G93A) mice and this was accompanied by heavy infiltration of CD8(+) T lymphocytes and macrophages. These phenomena were not detectable in the peripheral nervous system of fast-progressing mice. CONCLUSIONS: These data show for the first time that damaged MNs in SOD1-related ALS actively recruit immune cells in the peripheral nervous system to delay muscle denervation and prolong the lifespan. On the contrary, the lack of this response has a negative impact on the disease course
Steel-based applications in earthquake-prone areas
Steel-Earth project aims at distributing among technicians, engineers, design companies and standardization bodies the results of three past RFCS projects (Steel-Retro [3], Opus [2] and PrecaSteel [1]), providing useful tools for the design and for the retrofit of existing buildings. Technical documents and practical applications to case studies, regarding design of steel and composite steel/concrete buildings and innovative steel-based
techniques for the retrofit of existing r.c. and masonry constructions, have been elaborated and collected into a volume distributed during the final workshop of the dissemination project. Pre-normative and background documents concerning the design of steel and composite structures and the rehabilitation of existing constructions have been prepared. A lot of attention has been paid to the analysis of the influence of overstrength factors on the seismic design of steel and composite structures. The prepared documents have been distributed to the attending people and to the members of WG 2 (CEN/TC 250/SC 8/WG 2 “Steel and Composite Structures”) during the final workshop of the project. Technical sheets, working examples and background documents have been translated into several languages (German, French, Italian, Romanian and Greek) and are free available on the website of the project (https://www.steelconstruct.com/site/), where information regarding Steel-Earth are also presented.11 Workshops in Italy, Greece, Germany, Belgium, Portugal, Spain and Romania and 5 conferences in Emilia-Romagna have been organized, as well as 2 practical courses for engineers and academic people in Pavia (Italy). Flash-drives with the technical documents and applications elaborated in Steel-Earth have
been distributed to the attending people
POINT CLOUD EXPLOITATION FOR STRUCTURAL MODELING AND ANALYSIS: A RELIABLE WORKFLOW
none4noThe digitization and geometric knowledge of the historical built heritage is currently based on point cloud, that rarely or only partially is used as digital twin for structural analysis. The present work deals with historical artefacts survey, with particular reference to masonry structures, aimed to their structural analysis and assessment. In detail, the study proposes a methodology capable of employing semi-directly the original data obtained from the 3D digital survey for the generation of a Finite Element Model (FEM), used for structural analysis of masonry buildings.
The methodology described presents a reliable workflow with twofold purpose: the improvement of the transformation process of the point cloud in solid and subsequently obtain a high-quality and detailed model for structural analyses.
Through the application of the methodology to a case study, the method consistency was assessed, regarding the smoothness of the whole procedure and the dynamic characterization of the Finite Element Model. The main improvement in respect with similar or our previous workflows is obtained by the introduction of the retopology in data processing, allowing the transformation of the raw data into a solid model with optimal balancing between Level of Detail (LOD) and computational weight. Another significant aspect of the optimized process is undoubtedly the possibility of faithfully respecting the semantics of the structure, leading to the discretization of the model into different parts depending on the materials. This work may represent an excellent reference for the study of masonry artefacts belonging to the existing historical heritage, starting from surveys and with the purpose to structural and seismic evaluations, in the general framework of knowledge-based preservation of heritage.openLucidi, A.; Giordano, E.; Clementi, F.; Quattrini, R.Lucidi, A.; Giordano, E.; Clementi, F.; Quattrini, R
Comparison of sequence-capture and ddRAD approaches in resolving species and populations in hexacorallian anthozoans.
Genome-level sequencing is the next step in understanding species-level relationships within Anthozoa (soft corals, anemones, stony corals, and their kin) as morphological and PCR-directed (single-locus) sequencing methods often fall short of differentiating species. The sea anemone genus Metridium is a common northern temperate sea anemone whose species are difficult to differentiate using morphology alone. Here we use Metridium as a case study to confirm the low level of information available in six loci for species differentiation commonly sequenced for Actiniaria and explore and compare the efficacy of ddRAD and sequence-capture methods in species-level systematics and biogeographic studies. We produce phylogenetic trees from concatenated datasets and perform DAPC and STRUCTURE analyses using SNP data. The six conventional loci are not able to consistently differentiate species within Metridium. The sequence-capture dataset resulted in high support and resolution for both current species and relationships between geographic areas. The ddRAD datasets displayed ambiguity among species, and support between major geographic groupings was not as high as the sequence-capture datasets. The level of resolution and support resulting from the sequence-capture data, combined with the ability to add additional individuals and expand beyond the genus Metridium over time, emphasizes the utility of sequence-capture methods for both systematics and future biogeographic studies within anthozoans. We discuss the strengths and weaknesses of the genomic approaches in light of our findings and suggest potential implications for the biogeography of Metridium based on our sampling
Species replacement dominates megabenthos beta diversity in a remote seamount setting
Seamounts are proposed to be hotspots of deep-sea biodiversity, a pattern potentially arising from increased productivity in a heterogeneous landscape leading to either high species co-existence or species turnover (beta diversity). However, studies on individual seamounts remain rare, hindering our understanding of the underlying causes of local changes in beta diversity. Here, we investigated processes behind beta diversity using ROV video, coupled with oceanographic and quantitative terrain parameters, over a depth gradient in Annan Seamount, Equatorial Atlantic. By applying recently developed beta diversity analyses, we identified ecologically unique sites and distinguished between two beta diversity processes: species replacement and changes in species richness. The total beta diversity was high with an index of 0.92 out of 1 and was dominated by species replacement (68%). Species replacement was affected by depth-related variables, including temperature and water mass in addition to the aspect and local elevation of the seabed. In contrast, changes in species richness component were affected only by the water mass. Water mass, along with substrate also affected differences in species abundance. This study identified, for the first time on seamount megabenthos, the different beta diversity components and drivers, which can contribute towards understanding and protecting regional deep-sea biodiversity
A fully automatic nerve segmentation and morphometric parameter quantification system for early diagnosis of diabetic neuropathy in corneal images
Diabetic Peripheral Neuropathy (DPN) is one of the most common types of diabetes that can affect the cornea. An accurate analysis of the nerve structures can assist the early diagnosis of this disease. This paper proposes a robust, fast and fully automatic nerve segmentation and morphometric parameter quantification system for corneal confocal microscope images. The segmentation part consists of three main steps. First, a preprocessing step is applied to enhance the visibility of the nerves and remove noise using anisotropic diffusion filtering, specifically a Coherence filter followed by Gaussian filtering. Second, morphological operations are applied to remove unwanted objects in the input image such as epithelial cells and small nerve segments. Finally, an edge detection step is applied to detect all the nerves in the input image. In this step, an efficient algorithm for connecting discontinuous nerves is proposed. In the morphometric parameters quantification part, a number of features are extracted, including thickness, tortuosity and length of nerve, which may be used for the early diagnosis of diabetic polyneuropathy and when planning Laser-Assisted in situ Keratomileusis (LASIK) or Photorefractive keratectomy (PRK). The performance of the proposed segmentation system is evaluated against manually traced ground-truth images based on a database consisting of 498 corneal sub-basal nerve images (238 are normal and 260 are abnormal). In addition, the robustness and efficiency of the proposed system in extracting morphometric features with clinical utility was evaluated in 919 images taken from healthy subjects and diabetic patients with and without neuropathy. We demonstrate rapid (13 seconds/image), robust and effective automated corneal nerve quantification. The proposed system will be deployed as a useful clinical tool to support the expertise of ophthalmologists and save the clinician time in a busy clinical setting
International criteria for electrocardiographic interpretation in athletes: Consensus statement.
Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD
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