Simulazione di evacuazione di folle in Alchemist: un modello di mappa mentale per pedoni cognitivi

La simulazione computerizzata di folle in movimento è stato un campo piuttosto attivo recentemente, con applicazioni che vanno dall’intrattenimento alla gestione della sicurezza in luoghi pubblici o privati. Le simulazioni di folle devono prendere in considerazione non solo gli aspetti fisici dell’ambiente e dei pedoni, ma anche i fattori psicologici e sociali che hanno un effetto sul movimento delle persone. La capacità di orientarsi all’interno di un ambiente è una caratteristica fondamentale dell'essere umano e in quanto tale è indispensabile per una simulazione realistica. Diversi modelli assumono che i pedoni abbiano conoscenza totale dell’ambiente, cioè che ne conoscano la topologia e le metriche per intero. Ciò può essere ammissibile quando il processo di navigazione è banale, ad esempio in una piazza, tuttavia in ambienti più complessi questa è una grezza approssimazione, in quanto difficilmente ciascun pedone ne possiede una conoscenza completa (specie se molte delle persone coinvolte visitano l’edificio per la prima volta). Lo scopo del lavoro corrente è modellare la rappresentazione mentale che ciascun pedone ha dell’ambiente circostante, spesso parziale e inaccurata, comunemente nota come mappa cognitiva, e il processo mentale in atto in ogni persona che usa tali informazioni per scegliere quale percorso o direzione seguire (cioè orientarsi). I modelli descritti sono poi implementati all’interno del simulatore Alchemist, l'approccio adottato è ad agenti. Di particolare interesse per il lavoro corrente sono le simulazioni di evacuazioni di folle, per il loro valore nel prevenire situazioni disastrose durante la pianificazione di eventi o la progettazione di edifici. Detto ciò, i modelli presentati sono pensati per essere usati in qualsiasi tipo di simulazione

Routing quantum information in spin chains

Two different models for performing efficiently routing of a quantum state are presented. Both cases involve an XX spin chain working as data bus and additional spins that play the role of sender and receivers, one of which is selected to be the target of the quantum state transmission protocol via a coherent quantum coupling mechanism making use of local/global magnetic fields. Quantum routing is achieved, in the first of the models considered, by weakly coupling the sender and the receiver to the data bus. In the second model, strong magnetic fields acting on additional spins located between the sender/receiver and the data bus allow us to perform high fidelity routing.Comment: added references in v

Investigation on the feasibility of integration of high temperature solar energy in a textile factory

Thermal energy production from fossil fuels is very common in many applications, especially in industrial processes. In a global context where great attention is being focused on reducing pollution and greenhouse gas production, the integration of renewable energy in industrial applications is very interesting. This is even more important considering that greenhouse gas emission for industrial processes is a great portion of their total emission. Considering the above, it appears that the integration of high temperature solar panels in industrial processes is quite an attractive prospect. The working temperatures of parabolic solar collectors are, for example, generally close to those of the thermal fluids used in many industrial processes, and parabolic solar collectors are a well known technology with several applications primarily used in electric production systems. Nonetheless, only a few examples of industrial integration have been studied or built. In this study, the integration of a concentrating solar thermal plant in a textile factory has been examined both from the thermodynamic and economic point of view. An existing textile factory was chosen as a case study and its annual consumption of thermal energy characterized. A model of the plant with solar energy integration was developed and simulated with TRNSYS over a one year time period. The plant was simulated considering the panel characteristics provided by the manufacturer and the local irradiation data. The influence of several plant parameters has been investigated in order to estimate their importance on performance and plant suitability

Transfer of arbitrary two-qubit states via a spin chain

We investigate the fidelity of the quantum state transfer (QST) of two qubits by means of an arbitrary spin- 1/2 network, on a lattice of any dimensionality. Under the assumptions that the network Hamiltonian preserves the magnetization and that a fully polarized initial state is taken for the lattice, we obtain a general formula for the average fidelity of the two qubits QST, linking it to the one- and two-particle transfer amplitudes of the spin excitations among the sites of the lattice. We then apply this formalism to a 1D spin chain with XX-Heisenberg type nearest-neighbour interactions adopting a protocol that is a generalization of the single qubit one proposed in Paganelli et al. [Phys. Rev. A 87, 062309 (2013)]. We find that a high-quality two qubit QST can be achieved provided one can control the local fields at sites near the sender and receiver. Under such conditions, we obtain an almost perfect transfer in a time that scales either linearly or, depending on the spin number, quadratically with the length of the chain

Spin chains for two-qubit teleportation

Generating high-quality multi-particle entanglement between communicating parties is the primary resource in quantum teleportation protocols. To this aim, we show that the natural dynamics of a single spin chain is able to sustain the generation of two pairs of Bell states - possibly shared between a sender and a distant receiver - which can in turn enable two-qubit teleportation. In particular, we address a spin-1/2 chain with XX interactions, connecting two pairs of spins located at its boundaries, playing the roles of sender and receiver. In the regime where both end pairs are weakly coupled to the spin chain, it is possible to generate at predefinite times a state that has vanishing infidelity with the product state of two Bell pairs, thereby providing nearly unit fidelity of teleportation. We also derive an effective Hamiltonian via a second-order perturbation approach that faithfully reproduces the dynamics of the full system.Comment: 11 pages, 4 figures. Comments welcom

Spirituality for Late Adolescents Coping with Grief and Loss

Experiencing the death of a loved one is often life changing, and learning ways to cope is an important part of the healing process. Such a change can be particularly difficult for late adolescents (individuals between 18 and 25 years of age) who are already going through significant life changes. Spirituality and mental health has received increasing scholarly attention in recent years, and the Association for Spirituality, Ethics, and Religious Values in Counseling has developed competencies for counselors to use when working with clients who wish to incorporate spirituality in their treatment. Despite increased interest in the field, there is little scholarly literature on the use of spirituality in counseling late adolescents who are experiencing grief and loss. The purpose of this hermeneutic phenomenological study was to explore the meaning and role of spirituality and spiritual practices in the grieving processes of late adolescents. Existential theory provided the framework for the study. Participants were recruited from a local grief center, college, and university as well as CESnet and ASERVIC listservs. Seven late adolescents took part in semistructured interviews regarding their grieving process. Lindseth and Norberg\u27s phenomenological hermeneutical method was used to analyze the data consisting of naïve reading, structural analysis, and comprehensive understanding. Themes included experiences with death, surviving the loss, and changes. Findings indicated that spiritual practices were beneficial in helping grieving late adolescents cope with the death of a loved one. Results may provide counselors with additional ways to work with this population during their grieving process

Positron emission tomography in the diagnostic work-up of screening-detected lung nodules

Low-dose computed tomography (CT) screening for lung cancer can reduce lung cancer mortality, but overdiagnosis, false positives and invasive procedures for benign nodules are worrying. We evaluated the utility of positron emission tomography (PET)-CT in characterising indeterminate screeningdetected lung nodules. 383 nodules, examined by PET-CT over the first 6 years of the COSMOS (Continuous Observation of Smoking Subjects) study to diagnose primary lung cancer, were reviewed and compared with pathological findings (surgically-treated patients) or follow-up (negative CT for â\u89¥2 years, considered negative); 196 nodules were malignant. The sensitivity, specificity and accuracy of PET-CT for differentially diagnosing malignant nodules were, respectively, 64%, 89% and 76% overall, and 82%, 92% and 88% for baseline-detected nodules. Performance was lower for nodules found at repeat annual scans, with sensitivity ranging from 22% for nonsolid to 79% for solid nodules (p=0.0001). Sensitivity (87%) and specificity (73%) were high for nodules â\u89¥15 mm, better (sensitivity 98%) for solid nodules â\u89¥15 mm. PET-CT was highly sensitive for the differential diagnosis of indeterminate nodules detected at baseline, nodules â\u89¥15 mm and solid nodules. Sensitivity was low for sub-solid nodules and nodules discovered after baseline for which other methods, e.g. volume doubling time, should be used

Intragastric gastric band migration: erosion: an analysis of multicenter experience on 177 patients

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) has proven to be a safe and effective surgical treatment for morbid obesity. It can be a simple, fast, reversible, anatomy-preserving procedure. Despite these advantages, its long-term efficacy came into question by the occurrence of complications such as intragastric band migration. Consistent information regarding this complication is still lacking. Treatment for migration is still being debated as well. Most of the inconsistencies of these data stem from the very low number of patients reported in single-center experiences or case reports. Lack of multicenter experience is evident. The aim of this study was to perform a retrospective analysis of data on intragastric migration in a large multicenter cohort of patients who underwent LAGB. METHODS: A retrospective multicenter study on LAGB patients was performed. Data had been entered into a prospective database of the Italian Group for LapBand(®) (GILB) since January 1997. Pars flaccida and perigastric positioning were considered along with different kinds of gastric bands by the same manufacturer. Time of diagnosis, mean body mass index (BMI), presentation symptoms, and conservative and surgical therapy of intragastric migration were considered. RESULTS: From January 1997 to December 2009, a total of 6,839 patients underwent LAGB and their data were recorded [5,660 females, 1,179 males; mean age 38.5 ± 18.2 years (range 21-62 years); mean BMI = 46.7 ± 7.7 kg/m(2) (range 37.3-68.3); excess weight (EW) 61.8 ± 25.4 kg (range 36-130); %EW 91.1 ± 32.4 % (range 21-112 %)]. A total of 177 of 6,839 (2.5 %) intragastric erosions were observed. According to the postoperative time of follow-up, the diagnosis of intragastric migration was made in 74 (41.8 %), 14 (7.9 %), 38 (21.4 %), 40 (22.6 %), 6 (3.4 %), and 4 (2.2 %) banded patients at 6-12, 24, 36, 48, 60, and 72 months after banding, respectively. Most of intragastric band migration during the first 2 years occurred in bands with no or a few milliliters of filling. In patients with late erosion, the bands were adjusted several times; no band was overfilled but one was filled to the maximum or submaximum with a maximum of two adjustments. Erosions diagnosed during the first 24 months were related to the experience of the surgical staff, while late erosions were not. CONCLUSIONS: Intragastric band migration or band erosion is a rare, disturbing, and usually not life-threatening complication of gastric banding. Its pathogenesis is probably linked to different mechanisms in early (technical failure in retrogastric passage) or late (band management) presentation. It is usually asymptomatic and there is no pathognomonic presentation. A wide range of therapeutic options are available, from simple endoscopic or laparoscopic removal to early or late band replacement or other bariatric procedure. More experience and more studies are needed to lower its presentation rate and definitively clarify its pathogenesis to address the right therapeutic option