5,073 research outputs found
Design and construction of the thin vault for the reinforced concrete ceiling of the Public Hall of the Cassa di Risparmio Bank headquarters in L’Aquila
[EN] The present article wants to report on the technological and constructive aspects related to the realization of the thin reinforced concrete vault for the reinforced concrete ceiling of the Cassa di Risparmio Bank Public Hall of L'Aquila; this work was carried out in the early 1950s on the occasion of the enlargement of the bank headquarters, built in the nineteenth-century . The intervention is seen peculiar because it can be considered representative of the application of the reinforced concrete technique to realize a small structural thickness reinforced concrete ceiling. In particular, the use of complex-shaped vaulted systems in reinforced concrete, in the post-war Italian period, was substantially reserved for the construction of road bridges in the post-war reconstruction context of the infrastructure system, less used in civil construction. The application of such construction systems, in architectural works, refers to buildings with a predominantly tertiary use, such as offices and exhibition halls. Among these, although of minor importance, there is the Public hall of the Cassa di Risparmio of L'Aquila which testifies that some reinforced concrete works, demanding from the constructive point of view, were carried out in the peripheral territorial areas as well, like the provincial ones. In particular, from the analysis of the archive sources, the re-enactement of the project phases as well as the construction ones, confirms the use of a building technique, which in that particular historical period, saw the transition from the structural calculation theories to the construction site practice and, its application not only in large Italian cities, but also in minor contexts.Di Giovanni, G. (2020). Design and construction of the thin vault for the reinforced concrete ceiling of the Public Hall of the Cassa di Risparmio Bank headquarters in L’Aquila. VITRUVIO - International Journal of Architectural Technology and Sustainability. 5(1):83-95. https://doi.org/10.4995/vitruvio-ijats.2020.13687OJS839551Capomolla R.(2007) Le forme organiche strutturali. Materia e spazio nelle opere di Sergio Musmeci, in Rassegna di Architettura e Urbanistica Anno XLI 121/122 - Ingegneria italiana, pag.135-148.Centofanti M. et al, Palazzo della Direzione generale Carispaq, (2011) in Milano L. et al.(a cura di) L'Università e la ricerca per l'Abruzzo. Il patrimonio culturale dopo il terremoto del 6 aprile 2009, Textus Edizioni.Ciranna S. (2009) Dall'Adriatico al Gran Sasso. Architetture e progetti del nuovo millennio. Gangemi Editore.Iori T. (2007) L'ingegneria del miracolo italiano, in Rassegna di Architettura e Urbanistica Anno XLI 121/122 - Ingegneria italiana, pag.33 - 59.Iori T.(2005) L'ingegneria italiana del dopoguerra: appunti per una storia. In G. Mochi (a cura di), Teoria e pratica del costruire: saperi, strumenti, modelli, vol II, pp.763-772.Poretti S. (2008) Modernismi Italiani. Architettura e costruzione nel Novecento. Gangemi Editore
Exploration of the Current State and Directions of Dynamic Ridesharing
Dynamic ridesharing (DRS) is an emerging transportation service based on the traditional concept of shared rides. DRS makes use of web-based real-time technologies to match drivers with riders. Enabling technologies include software platforms that operate on mobile communication devices and contain location-aware capabilities including Global Positioning Systems (Agatz, Erera, Savelsberg, & Wang, 2012). The platforms are designed to provide ride-matching services via smartphone applications differing from early systems that used non-real time services such as internet forums, or telecommunications, where responses were not immediate.
The study of DRS is important when considering its role as an emerging transportation demand management strategy. DRS reduces travel demand on singleoccupancy vehicles (SOVs) by filling vehicle seats that are typically left vacant. The most recent statistics of vehicle occupancy rates were measured in 2009 by the National Household Travel Survey (NHTS), conducted by the U.S. Department of Transportation. According to the NHTS, the 2009 occupancy rate for all purposes was a meager 1.67 persons per vehicle (Federal Highway Administration, 2015). Vehicle occupancy rates examined against the total of all registered highway vehicles in the U.S. as of 2012, calculated at 253,639,386 (Bureau of Transportation Statistics, 2015), reveals the magnitude of the impact of SOVs. Left unattended, the ramifications for environmental outcomes is substantial. Among the major energy consuming sectors, transportation\u27s share is largest in terms of total CO2 emissions at 32.9% (Davis, Diegel, & Boundy, 2014, p. 11-15).
DRS offers promise to fill empty vehicle seats. Evidence indicates that specific demographic subgroups are inclined to use DRS services. For example, data suggest that the subgroup of 18 to 34-year-olds, the so-called millennials , have negative attitudes towards private car ownership unlike previous age groups (Nelson, 2013). Data collected for this study revealed that the millennial subgroup represents half of all DRS users. Millennials also revealed they tended to use DRS more than other subgroups to replace a private vehicle. Further research is needed to determine if the trend towards DRS by 18 to 34-year-olds represents current economic factors or a fundamental cultural shift away from the SOV transportation model
The influence of a new clinical motion for endodontic instruments on the incidence of postoperative pain
Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain.MATERIALS AND METHODS:
100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test.
RESULTS:
For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique.
CONCLUSIONS:
Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation
The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle
Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis
Multi-Fractional Brownian Motion: Estimating the Hurst Exponent via Variational Smoothing with Applications in Finance
Beginning with the basics of the Wiener process, we consider limitations characterizing the “Brownian approach” in analyzing real phenomena. This leads us to first consider the fractional Brownian motion (fBm)—also discussing theWood–Chan fast algorithm to generate sample paths—to then focus on multi-fBm and methods to generate its trajectories. This is heavily linked to the Hurst exponent study, which we link to real data, firstly considering an absolute moment method, allowing us to obtain raw estimates, to then consider variational calculus approaches allowing to smooth it. The latter smoothing tool was tested in accuracy on synthetic data, comparing it with the exponential moving average method. Previous analyses and results were exploited to develop a forecasting procedure applied to the real data of foreign exchange rates from the Forex market
Combined quantum state preparation and laser cooling of a continuous beam of cold atoms
We use two-laser optical pumping on a continuous atomic fountain in order to
prepare cold cesium atoms in the same quantum ground state. A first laser
excites the F=4 ground state to pump the atoms toward F=3 while a second
pi-polarized laser excites the F=3 -> F'=3 transition of the D2 line to produce
Zeeman pumping toward m=0. To avoid trap states, we implement the first laser
in a 2D optical lattice geometry, thereby creating polarization gradients. This
configuration has the advantage of simultaneously producing Sisyphus cooling
when the optical lattice laser is tuned between the F=4 -> F'=4 and F=4 -> F'=5
transitions of the D2 line, which is important to remove the heat produced by
optical pumping. Detuning the frequency of the second pi-polarized laser
reveals the action of a new mechanism improving both laser cooling and state
preparation efficiency. A physical interpretation of this mechanism is
discussed.Comment: Minor changes according to the recommendations of the referee: -
Corrected Fig.1. - Split the graph of Fig.6 for clarity. - Added one
reference. - Added two remarks in the conclusion. - Results unchange
Treatment timing and multidisciplinary approach in Apert syndrome
Apert syndrome is a rare congenital disorder characterized by craniosynostosis, midface hypoplasia and symmetric syndactyly of hands and feet. Abnormalities associated with Apert syndrome include premature fusion of coronal sutures system (coronal sutures and less frequently lambdoid suture) resulting in brachiturricephalic dismorphism and impaired skull base growth.
After this brief explanation it is clear that these anatomical abnormalities may have a negative impact on the ability to perform essential functions.
Due to the complexity of the syndrome a multidisciplinary (respiratory, cerebral, maxillo-mandibular, dental, ophthalmic and orthopaedic) approach is necessary in treating the psychological, aesthetic and functional issues. The aim of this paper is to analyse the different functional issues and surgical methods trying to enhance results through a treatment plan which includes different specialities involved in Apert syndrome treatment. Reduced intellectual capacity is associated to the high number of general anaesthesia the small patients are subject to. Therefore the diagnostic and therapeutic treatment plan in these patients has established integrated and tailored surgical procedures based on the patients’ age in order to reduce the number of general anaesthesia, thus simplifying therapy for both Apert patients and their family members
New technologies to improve root canal disinfection
Effective irrigant delivery and agitation are prerequisites to promote root canal disinfection and debris removal and improve successful endodontic treatment. This paper presents an overview of the currently available technologies to improve the cleaning of the endodontic space and their debridement efficacy. A PubMed electronic search was conducted with appropriate key words to identify the relevant literature on this topic. After retrieving the full-text articles, all the articles were reviewed and the most appropriate were included in this review. Several different systems of mechanical activation of irrigants to improve endodontic disinfection were analysed: manual agitation with gutta-percha cones, endodontic instruments or special brushes, vibrating systems activated by low-speed hand-pieces or by sonic or subsonic energy, use of ultrasonic or laser energy to mechanically activate the irrigants and apical negative pressure irrigation systems. Furthermore, this review aims to describe systems designed to improve the intracanal bacterial decontamination by a specific chemical action, such as ozone, direct laser action or light-activated disinfection. The ultrasonic activation of root canal irrigants and of sodium hypochlorite in particular still remains the gold standard to which all other systems of mechanical agitation analyzed in this article were compared. From this overview, it is evident that the use of different irrigation systems can provide several advantages in the clinical endodontic outcome and that integration of new technologies, coupled with enhanced techniques and materials, may help everyday clinical practice
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