Integrated process of images and acceleration measurements for damage detection

The use of mobile robots and UAV to catch unthinkable images together with on-site global automated acceleration measurements easy achievable by wireless sensors, able of remote data transfer, have strongly enhanced the capability of defect and damage evaluation in bridges. A sequential procedure is, here, proposed for damage monitoring and bridge condition assessment based on both: digital image processing for survey and defect evaluation and structural identification based on acceleration measurements. A steel bridge has been simultaneously inspected by UAV to acquire images using visible light, or infrared radiation, and monitored through a wireless sensor network (WSN) measuring structural vibrations. First, image processing has been used to construct a geometrical model and to quantify corrosion extension. Then, the consistent structural model has been updated based on the modal quantities identified using the acceleration measurements acquired by the deployed WSN. © 2017 The Authors. Published by Elsevier Ltd

β-arrestin1-E2F1-ac axis regulates physiological apoptosis and cell cycle exit in cellular models of early postnatal cerebellum

Development of the cerebellum is characterized by rapid proliferation of cerebellar granule cell precursors (GCPs) induced by paracrine stimulation of Sonic hedgehog (Shh) signaling from Purkinje cells, in the external granular layer (EGL). Then, granule cell precursors differentiate and migrate into the inner granular layer (IGL) of the cerebellum to form a terminally differentiated cell compartment. Aberrant activation of Sonic hedgehog signaling leads to granule cell precursors hyperproliferation and the onset of Sonic hedgehog medulloblastoma (MB), the most common embryonal brain tumor. β-arrestin1 (ARRB1) protein plays an important role downstream of Smoothened, a component of the Sonic hedgehog pathway. In the medulloblastoma context, β-arrestin1 is involved in a regulatory axis in association with the acetyltransferase P300, leading to the acetylated form of the transcription factor E2F1 (E2F1-ac) and redirecting its activity toward pro-apoptotic gene targets. This axis in the granule cell precursors physiological context has not been investigated yet. In this study, we demonstrate that β-arrestin1 has antiproliferative and pro-apoptotic functions in cerebellar development. β-arrestin1 silencing increases proliferation of Sonic hedgehog treated-cerebellar precursor cells while decreases the transcription of E2F1-ac pro-apoptotic targets genes, thus impairing apoptosis. Indeed, chromatin immunoprecipitation experiments show a direct interaction between β-arrestin1 and the promoter regions of the pro-apoptotic E2F1 target gene and P27, indicating the double role of β-arrestin1 in controlling apoptosis and cell cycle exit in a physiological context. Our data elucidate the role of β-arrestin1 in the early postnatal stages of cerebellar development, in those cell compartments that give rise to medulloblastoma. This series of experiments suggests that the physiological function of β-arrestin1 in neuronal progenitors is to directly control, cooperating with E2F1 acetylated form, transcription of pro-apoptotic genes

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Field observations and failure analysis of the Basilica S. Maria di Collemaggio after the 2009 L'Aquila earthquake

On Monday, the 6th of April, 2009, a devastating earthquake struck L'Aquila causing the partial collapse of the Basilica S. Maria di Collemaggio, an important symbol of the city. The mechanism of the transept structure's failure, which left the external boundary walls almost undamaged, probably due to the sudden collapse of the large multi-lobed pillars at the end of the nave, is discussed in the paper by different points of view. A brief historical review of the monument restorations is followed by the analysis of the damage scenario recorded during the post-earthquake inspections. Finite element models of the Basilica, updated on the basis of available dynamic tests, have been used to perform a seismic assessment by response spectrum analysis according to the current Italian code, showing a high vulnerability, in the transversal direction larger than in the longitudinal one. The AQK earthquake accelerograms, recorded close to the site, have evidenced a prevailing component almost aligned with the longitudinal Basilica axis; the intensity is comparable with the one provided by the code, with exception in the vertical one greater than expected. Static nonlinear analyses have furnished the crack propagation in the masonry walls due to the increase of longitudinal horizontal loads. The presented failure description obtained by structural modeling is coherent with the direction of the registered polarized seismic action and it is compatible with the observed damage and with most of the debris positions coming from the collapse of the transept structures. (C) 2013 Elsevier Ltd. All rights reserved.On Monday, the 6th of April, 2009, a devastating earthquake struck L’Aquila causing the partial collapse of the Basilica S. Maria di Collemaggio, an important symbol of the city. The mechanism of the transept structure’s failure, which left the external boundary walls almost undamaged, probably due to the sudden collapse of the large multi-lobed pillars at the end of the nave, is discussed in the paper by different points of view. A brief historical review of the monument restorations is followed by the analysis of the damage scenario recorded during the post-earthquake inspections. Finite element models of the Basilica, updated on the basis of available dynamic tests, have been used to perform a seismic assessment by response spectrum analysis according to the current Italian code, showing a high vulnerability, in the transversal direction larger than in the longitudinal one. The AQK earthquake accelerograms, recorded close to the site, have evidenced a prevailing component almost aligned with the longitudinal Basilica axis; the intensity is comparable with the one provided by the code, with exception in the vertical one greater than expected. Static nonlinear analyses have furnished the crack propagation in the masonry walls due to the increase of longitudinal horizontal loads. The presented failure description obtained by structural modeling is coherent with the direction of the registered polarized seismic action and it is compatible with the observed damage and with most of the debris positions coming from the collapse of the transept structures

Workshop on Cloud Services for File Synchronisation and Sharing

We have set-up an OpenStack-based cloud infrastructure in the framework of a publicly funded project, PRISMA, aimed at the implementation of a fully integrated PaaS+IaaS platform to provide services in the field of smart-government (e-health, e-government, etc.). The IaaS testbed currently consists of 18 compute nodes providing in total almost 600 cores, 3550 GB of RAM, 400 TB of storage (disks). Connectivity is ensured through 2 NICs, 1Gbit/s and 10Gbit/s. Both the backend (MySQL database and RabbitMq message broker) and the core services (nova, keystone, glance, neutron, etc.) have been configured in high-availability using HA clustering techniques. The full capacity available by 2015 will provide 2000 cores and 8 TB of RAM. In this work we present the storage solutions that we are currently using as backend for our production cloud services. Storage is one of the key components of the cloud stack and can be used both to host the running VMs (“ephemeral” storage), and to host persistent data such as the block devices used by the VMs or users’ archived unstructured data, backups, virtual images, etc.. The storage-as-service is implemented in Openstack by the Block Storage project, Cinder, and the Object Storage project, Swift. Selecting the right software to manage the underlying backend storage for these services is very important and decisions can depend on many factors, not only merely technical, but also economic: in most cases they result from a trade-off between performance and costs. Many operators use separate compute and storage hosts. We decided not to follow this mainstream trend aiming at the best cost-performance scenario: for us it makes sense to run compute and storage on the same machines since we want to be able to dedicate as many of our hosts as possible to running instances. Therefore, each compute node is configured with a significant amount of disk space and a distributed file system (GlusterFS and/or Ceph) ties the disks from each compute node into a single file-system. In this case, the reliability and stability of the shared file-system is critical and defines the effort to maintain the compute hosts: tests have been performed to asses the stability of the shared file-systems changing the replica factor. For example, we observed that GlusterFS in replica 2 cannot be used in production because highly unstable even at moderate storage sizes. Our experience can be useful for all those organizations that have specific constraints in the procurement of a compute cluster or need to deploy on pre-existing servers for which they have little or no control over their specifications. Moreover, the solution we propose is flexible enough, since it is always possible to add external storage when additional storage is required. We currently use GlusterFS distributed file system for: - storage of the running VMs enabling the live migration, - storage of the virtual images (as primary Glance image store), - implementation of one of the Cinder backends for block devices. In particular, we have been using Cinder with LVM-iSCSI driver since Grizzly release when the GlusterFS driver for Cinder did not support advanced features like snapshots and clones, fundamental for our use-cases. In order to exploit GlusterFS advantages even using LVM driver, we created the Cinder volume groups on GlusterFS loopback devices. Upgrading our infrastructure to Havana, we decided to enable Ceph as additional backend of Cinder in order to compare features, reliability and performances of the two solutions. Our interest for Ceph derives also from the possibility to consolidate the infrastructure overall backend storage into a unified solution. To this aim, currently we are testing Ceph to run the Virtual Machines, both using RBD and Ceph-FS protocols, and to implement the object storage. In order to test the scalability and performance of the deployed system using test cases which are derived from the typical pattern of storage utilization. The tools used for testing are standard software widely used for this purpose such as: iozone and/or dd for block storage and specific benchmarking tools like Cosbench, swift-bench and ssbench for the object storage. Using different tools for testing the file-system and comparing their results with the observation of the real test case, is also a good possibility for testing the reliability of the benchmarking tools. Throughput tests have been planned and conducted on the two system configurations in order to understand the performance of both storage solutions and its impacts to applications aiming at achieving the better SLA and end-users experience. Implementing our cloud platform, we focused also on providing transparent access to data using standardized protocols (both de-iure and de-facto standards). In particular, Amazon-compliant S3 and the CDMI (Cloud Data Management Interface) interfaces have been installed on top of the Swift Object Storage in order to promote interoperability also at PaaS/SaaS levels. Data is important for businesses of all sizes. Therefore, one of the most common user requirement is the possibility to backup data in order to minimize their loss, stay compliant and preserve data integrity. Implementing this feature is particularly challenging when the users come from the public administrations and the scientific communities that produce huge quantities of heterogeneous data and/or can have strict constraints. An interesting feature of the Swift Object Storage is the geographic replica that can be used in order to add a disaster-recovery feature to the set of data and services exposed by our infrastructure. Also Ceph provides a similar feature: the geo-replication through RADOS gateway. Therefore, we have installed and configured both a Swift global cluster and a Ceph federated cluster, distributed on three different geographic sites. Results of the performance tests conducted on both clusters are presented along with a description of the parameters tuning that has been performed for optimization. The different replication methods implemented in the two middlewares, Swift and Ceph, are compared in terms of network traffic bandwidth, cpu and memory consumption. Another important aspect we are taking care of is the QoS (Quality of Service) support, i.e. the capability of providing different levels of storage service optimized wrt the user application profile. This can be achieved defining different tiers of storage and setting parameters like how many I/Os the storage can handle, what limit it should have on latency, what availability levels it should offer and so on. Our final goal is also to set-up a (semi-)automated system that is able of self-optimising. Therefore we are exploring the cache tiering feature of Ceph, that handles the migration of data between the cache tier and the backing storage tier automatically. Results of these testing activities will be shown too in this presentation

Comparative study of vibration-based parametric identification techniques for a three-dimensional frame structure

The entire structural identification process, starting from measurement of the experimental response to ambient vibration, and concluding with the assessment of a representative dynamic model, depends upon an informed selection of appropriate data treatment techniques. The paper compares different procedures for identifying both modal and physical models. Four approaches (EFFD, ERA, SSI, and TFIE) for output-only modal identification are discussed. Their performance is evaluated using experimental data extracted from the ambient vibration response of a three-dimensional frame. The discussion of the identification results throws light on the intrinsic characteristics of each procedure, while the particular features of the structure, presenting unexpected local modes, demonstrate the necessity of a hierarchical treatment of the available information, based on a solid engineering knowledge. The calibration of a physical model is approached using an exact inverse procedure, based on a parametric analytical model, or automatic techniques of error minimization, based on finite element multi-models. The achievement of a good relative agreement, measured through performance-based indexes, increases the general confidence on the results independently obtained from each modal identification and model updating method

Dynamic testing and health monitoring via wireless sensor networks in the post-earthquake assessment of structural conditions at L\u2019Aquila

The use of vibration measures during ambient dynamic testing or integrated within permanent structural health monitoring systems may play a fundamental role in urban areas rich of strategic and monumental buildings, especially in postearthquake scenarios, as the city of L\u2019Aquila, struck by the devastating seismic events of April 2006. In particular, a careful use of different output-only identification procedures may help in extracting the structural signature from low-cost and easy-to-deployed wireless networks of dynamic sensors. This valuable experimental information may significantly increase the general confidence in understanding the real dynamic behavior of the structures which suffered moderate or severe damage due to the seismic action. The paper presents a pair of case-studies related to a historical church (the \u201cBasilica di Collemaggio\u201d) and some modern buildings (the Engineering Faculty of L\u2019Aquila), currently object of wide-spectrum analyses, including dynamic testing and structural model updating aiming to design retrofitting interventions. On this respect, the initial deployment and the current development of a permanent monitoring system based on a wireless network of accelerometers is illustrated