Damping of liquid sloshing by foams: from everyday observations to liquid transport

We perform experiments on the sloshing dynamics of liquids in a rectangular container submitted to an impulse. We show that when foam is placed on top of the liquid the oscillations of the free interface are significantly damped. The ability to reduce sloshing and associated splashing could find applications in numerous industrial processes involving liquid transport.Comment: Accepted for publication in Journal of Visualizatio

A genetic algorithm for combined topology and shape optimisations

A method to find optimal topology and shape of structures is presented. With the first the optimal distribution of an assigned mass is found using an approach based on homogenisation theory, that seeks in which elements of a meshed domain it is present mass; with the second the discontinuous boundaries are smoothed. The problem of the optimal topology search has an ON/OFF nature and has suggested the employment of genetic algorithms. Thus in this paper a genetic algorithm has been developed, which uses as design variables, in the topology optimisation, the relative densities (with respect to effective material density) 0 or 1 of each element of the structure and, in the shape one, the coordinates of the keypoints of changeable boundaries constituted by curves. In both the steps the aim is that to find the variable sets producing the maximum stiffness of the structure, respecting an upper limit on the employed mass. The structural evaluations are carried out with a FEM commercial code, linked to the algorithm. Some applications have been performed and results compared with solutions reported in literature. \uc2\ua9 2003 Elsevier Science Ltd. All rights reserved

Lay-up optimization for the hull of a racing sailing yacht

Deformability and buckling load of yacht hulls with fiber reinforced plastic sandwich structure depend on the stack sequence of the skins. In this work an optimization of fiber directions of the laminae for a racing yacht is proposed. This procedure has been divided into three parts (i.e. material characterization, surface model definition, lay-up optimization). First of all a set of unidirectional specimens has been realized, by using the same fibers and matrix (carbon/epoxy) used for the hull as well as the same procedure and workers, in order to characterize the material according to American Society for Testing and Materials (ASTM) Standard D3039, employing strain gage technique. In the second part, by means of an original software in Turbo-Pascal (which uses the half-width value matrix as an input) linked to Pro/ENGINEER, it has been possible to obtain the body plan and surface and finite element (FE) models of the sailing yacht for the subsequent analyses. In the third step, an optimization procedure that uses the results of FE structural analyses in three different sailing configurations is performed, with the aim of obtaining the fiber directions that are able to minimize the yacht deformability, also taking into account the buckling loads. An approximate analytical model has been used in conjunction with a sweep technique in order to evaluate the best of the solutions

Myelin pathology: Involvement of molecular chaperones and the promise of chaperonotherapy

The process of axon myelination involves various proteins including molecular chaperones. Myelin alteration is a common feature in neurological diseases due to structural and functional abnormalities of one or more myelin proteins. Genetic proteinopathies may occur either in the presence of a normal chaperoning system, which is unable to assist the defective myelin protein in its folding and migration, or due to mutations in chaperone genes, leading to functional defects in assisting myelin maturation/migration. The latter are a subgroup of genetic chaperonopathies causing demyelination. In this brief review, we describe some paradigmatic examples pertaining to the chaperonins Hsp60 (HSPD1, or HSP60, or Cpn60) and CCT (chaperonin-containing TCP-1). Our aim is to make scientists and physicians aware of the possibility and advantages of classifying patients depending on the presence or absence of a chaperonopathy. In turn, this subclassification will allow the development of novel therapeutic strategies (chaperonotherapy) by using molecular chaperones as agents or targets for treatment

Sequential importance sampling for multi-resolution Kingman-Tajima coalescent counting

Statistical inference of evolutionary parameters from molecular sequence data relies on coalescent models to account for the shared genealogical ancestry of the samples. However, inferential algorithms do not scale to available data sets. A strategy to improve computational efficiency is to rely on simpler coalescent and mutation models, resulting in smaller hidden state spaces. An estimate of the cardinality of the state-space of genealogical trees at different resolutions is essential to decide the best modeling strategy for a given dataset. To our knowledge, there is neither an exact nor approximate method to determine these cardinalities. We propose a sequential importance sampling algorithm to estimate the cardinality of the space of genealogical trees under different coalescent resolutions. Our sampling scheme proceeds sequentially across the set of combinatorial constraints imposed by the data. We analyse the cardinality of different genealogical tree spaces on simulations to study the settings that favor coarser resolutions. We estimate the cardinality of genealogical tree spaces from mtDNA data from the 1000 genomes and a sample from a Melanesian population to illustrate the settings in which it is advantageous to employ coarser resolutions

Lava flow susceptibility map of mt etna based on numerical simulations

We constructed maps of probability of lava inundation using computer simulations considering the past eruptive behaviour of the Mt. Etna volcano and data deriving from monitoring networks. The basic a priori assumption is that new volcanoes will not form far from existing ones and that such a distribution can be performed using a Cauchy kernel. Geophysical data are useful to update or fine tune the initial Cauchy kernel to better reflect the distribution of future volcanism. In order to obtain a final susceptibility map, a statistical analysis permits a classification of Etna’s flank eruptions into twelve types. The simulation method consists of creating a probability surface of the location of future eruption vents and segmenting the region according to the most likely historical eruption on which to base the simulation. The paths of lava flows were calculated using the MAGFLOW Cellular Automata (CA) model, allowing us to simulate the discharge rate dependent spread of lava as a function of time

Online Fault Classification in HPC Systems through Machine Learning

As High-Performance Computing (HPC) systems strive towards the exascale goal, studies suggest that they will experience excessive failure rates. For this reason, detecting and classifying faults in HPC systems as they occur and initiating corrective actions before they can transform into failures will be essential for continued operation. In this paper, we propose a fault classification method for HPC systems based on machine learning that has been designed specifically to operate with live streamed data. We cast the problem and its solution within realistic operating constraints of online use. Our results show that almost perfect classification accuracy can be reached for different fault types with low computational overhead and minimal delay. We have based our study on a local dataset, which we make publicly available, that was acquired by injecting faults to an in-house experimental HPC system.Comment: Accepted for publication at the Euro-Par 2019 conferenc

High-risk human papilloma virus, precancerous lesions and cancer in anal condylomas

INTRODUCTION: anal condylomas are associated with human papillomavirus (HPV) infection and are a risk factor for anal squamous cell carcinoma (SCC). OBJECTIVE: to conduct a meta-analysis evaluating the prevalence of anal high-risk-HPV, high-grade squamous intraepithelial lesions (HSIL) and SCC in patients with condylomas. The standardised incidence ratio (SIR) and the incidence rate (IR) of anal SCC were also calculated. METHODS: three electronic databases were searched until April 2020. Meta-analyses were performed using random effects models. RESULTS: pooled prevalence estimate of HR-HPV in anal condylomas was 40.2% (21.0 - 63.1) in immunocompromised and 16.4% (10.7 - 24.3) in non-immunocompromised patients, with an odds ratio (OR) of 3.79 (1.51-9.52, P = 0.005) for immunocompromised patients. HR-HPV in condylomas with HSIL was 73.8% (39.1 - 92.5) and in non-HSIL cases was 17.7% (9.6 - 30.2), corresponding to an OR of 12.33 (2.97-51.21, P = 0.001) for those with HSIL. The prevalence of HSIL in condylomas was 24.0% (16.4 - 33.7) in immunocompromised and 11.8% (7.2 - 18.8) in non-immunocompromised patients, with an OR of 2.51 (1.72-3.65, P < 0.001) for immunocompromised patients. The overall prevalence of anal SCC was 0.3% (0.0 - 1.7). The SIR of anal SCC was 10.7 (8.5 - 13.5), 20.1 (14.4 - 28.2) in men and 7.7 (5.6 - 10.5) in women. The overall IR of anal SCC was 6.5 per 100 000 persons-year (3.6 - 11.7), 12.7 (9.1 - 17.8) in men and 4.7 (1.7 - 13) in women. CONCLUSION: patients with a history of anal condylomas have a high risk of anal SCC, especially men. The prevalence of HR-HPV and HSIL in condylomas from immunocompromised patients is high. This information can change patient follow-up and treatment