Encounters with Valletta : a baroque city through the ages

This article explores life in nineteenth-century Valletta, and the cross-currents between British and Maltese culture which developed at this period. The first century of British colonial policies and influence in Malta left a deep mark on all aspects of life in the city – on its society, education, housing, religious buildings and practices, as well as on leisure including theatre and public gardens.peer-reviewe

Card-Based Zero-Knowledge Proof for Sudoku

In 2009, Gradwohl, Naor, Pinkas, and Rothblum proposed physical zero-knowledge proof protocols for Sudoku. That is, for a puzzle instance of Sudoku, their excellent protocols allow a prover to convince a verifier that there is a solution to the Sudoku puzzle and that he/she knows it, without revealing any information about the solution. The possible drawback is that the existing protocols have a soundness error with a non-zero probability or need special cards (such as scratch-off cards). Thus, in this study, we propose new protocols to perform zero-knowledge proof for Sudoku that use a normal deck of playing cards and have no soundness error. Our protocols can be easily implemented by humans with a reasonable number of playing cards

Secure Grouping Protocol Using a Deck of Cards

We consider a problem, which we call secure grouping, of dividing a number of parties into some subsets (groups) in the following manner: Each party has to know the other members of his/her group, while he/she may not know anything about how the remaining parties are divided (except for certain public predetermined constraints, such as the number of parties in each group). In this paper, we construct an information-theoretically secure protocol using a deck of physical cards to solve the problem, which is jointly executable by the parties themselves without a trusted third party. Despite the non-triviality and the potential usefulness of the secure grouping, our proposed protocol is fairly simple to describe and execute. Our protocol is based on algebraic properties of conjugate permutations. A key ingredient of our protocol is our new techniques to apply multiplication and inverse operations to hidden permutations (i.e., those encoded by using face-down cards), which would be of independent interest and would have various potential applications

Card-based Protocols Using Triangle Cards

Suppose that three boys and three girls attend a party. Each boy and girl have a crush on exactly one of the three girls and three boys, respectively. The following dilemma arises: On one hand, each person thinks that if there is a mutual affection between a girl and boy, the couple should go on a date the next day. On the other hand, everyone wants to avoid the possible embarrassing situation in which their heart is broken "publicly." In this paper, we solve the dilemma using novel cards called triangle cards. The number of cards required is only six, which is minimal in the case where each player commits their input at the beginning of the protocol. We also construct multiplication and addition protocols based on triangle cards. Combining these protocols, we can securely compute any function f: {0,1,2}^n --> {0,1,2}

Declino degli ambienti umidi in Sicilia: primo elenco delle zone scomparse

Questo lavoro fornisce un resoconto preliminare degli ambienti umidi (aree lacustri, stagni permanenti e temporanei, pantani salmastri o d’acqua dolce, spesso indicati coi nomi vernacolari “gorgo”, “biviere”, ecc.) presenti in Sicilia fino a pochi secoli o decenni fa. I dati di questa ricerca - desunti sia da resoconti sulle bonifiche a scopo agricolo e per la lotta alla malaria sia dalla letteratura botanica, storica e geografica - evidenziano un numero sorprendentemente elevato di corpi idrici ed enfatizzano l’importante ruolo giocato dagli alvei e dagli estuari dei fiumi nella dinamica e ricchezza complessiva delle aree inondate del passato. Questi ecosistemi hanno svolto un ruolo cruciale come stepping stone per numerosi organismi (es.: piante, alghe, uccelli, anfibi, molluschi, crostacei e insetti) acquatici e igrofili, un tempo decisamente più comuni sull’isola ma oggi spesso minacciati o persino estinti a livello regionale. Nel corso degli ultimi secoli questi ambienti sono stati “bonificati”, cioè profondamente trasformati attraverso interventi di drenaggio e/o interramento, dalla deviazione e regimazione dei corsi fluviali, dall’eccessivo sfruttamento della falda con la conseguente scomparsa o salinizzazione delle acque. Ciò ha comportato la forte riduzione e l’alterazione spesso irreversibile di interi ecosistemi, come le torbiere d’alta quota e numerosi pantani costieri, scomparsi ormai da tempo insieme al loro ricco patrimonio biologico. Stessa sorte è toccata a molti ambienti umidi delle isole satelliti, “vulnerabili per natura” per le loro ridotte dimensioni, l’isolamento e l’estrema localizzazione. Altre zone acquitrinose sono state cancellate dall’urbanizzazione (Palermo, Catania, Trapani, Messina) o dall’industrializzazione (Gela, Milazzo, Augusta-Melilli-Priolo Gargallo, Termini Imerese), dalle bonifiche e/o dall’intensificazione delle pratiche agricole (es.: Piana del Simeto, Calatino, Piana di Gela, pianure costiere fra Termini Imerese e Campofelice di Roccella, fra Acate, Comiso e Vittoria, fra Scicli e Ispica, fra Pozzallo e Pachino e fra Castelvetrano e Menfi). Molti di questi ambienti sono scomparsi prima che fossero studiati dai biologi. Le prime analisi sulla toponomastica regionale rivelano la grande abbondanza di aree umide anche nell’entroterra. La scarsa attenzione e memoria di questi luoghi è sottolineata dalla scarsezza delle informazioni disponibili e dalla difficoltà di localizzare correttamente molti di essi. Una valutazione a posteriori delle bonifiche effettuate fra il XIX e il XX secolo pone in risalto le contraddizioni delle dichiarate finalità agricole e sanitarie (lotta alla malaria) di tali interventi ed il loro parziale fallimento nel medio termine. Viene inoltre denunciata la prosecuzione delle bonifiche e manomissioni indiscriminate degli ambienti lentici in barba a leggi e regolamenti vigenti e a dispetto di direttive e convenzioni internazionali. Si accenna infine alle poche best practice finora realizzate a favore degli ambienti umidi siciliani, volte ad una loro tutela dinamica e valorizzazione, e alla possibilità concreta di ripristinare alcuni dei ghost pond di maggiore interesse.This paper provides a preliminary account of the wetlands (lakes, permanent and temporary ponds, brackish or freshwater marshes, often mentioned with the vernacular names “gorgo”, “biviere”, etc.) present on the island until a few centuries or decades ago. The first data of this research – derived either from reports on land reclamation for agricultural purposes or to fight against malaria or from botanical, historical and geographical literature – highlight a surprisingly large number of water bodies and emphasize the paramount role played by riverbeds and estuaries in the overall dynamics and richness of past flooded areas. These ecosystems have played a crucial role as stepping-stones for numerous aquatic and hygrophilous organisms (e. g. plants, algae, birds, amphibians, mollusks, crustaceans, and insects), once much more common on the island but nowadays often threatened or even extinct at regional level. Over the last centuries these environments have been reclaimed, i. e. deeply transformed through drainage and/or burial interventions, by the deviation and regulation of river courses, by the excessive exploitation of the watershed leading to water shortage or salinization. This has led to the strong reduction and often irreversible alteration of entire ecosystems, such as high-altitude peatlands and numerous coastal marshes, which have long since disappeared together with their rich biological heritage. The same fate has befallen many humid environments of the satellite islands, “vulnerable by nature” due to their small size, isolation, and extreme location. Other wetlands have been erased by urbanization (Palermo, Catania, Trapani, Messina) or industrialization (Gela, Milazzo, Augusta-Melilli-Priolo Gargallo, Termini Imerese), land reclamation and/or intensification of agricultural practices (e. g., Simeto Plain, Calatino district, Plain of Gela, plains between Termini Imerese and Campofelice di Roccella, Scicli and Ispica, Acate, Comiso and Vittoria, Scicli and Ispica, Pozzallo and Pachino, Castelvetrano and Menfi). Many of these environments disappeared before they were studied by biologists. The first analyses of regional toponyms reveal the great abundance of wetlands also in inland areas. The lack of attention and memory of these places is underlined by the scarce information available and the difficulty of correctly locating many of them. An ex-post evaluation of the reclamations carried out between the nineteenth and twentieth centuries highlights the contradictions of the declared agricultural and health purposes (fight against malaria) of these interventions and their partial failure in the medium term. The continuation of the reclamation and indiscriminate disruption of lentic environments, in defiance of laws and regulations in force, and in spite of international directives and conventions, is also denounced. Finally, mention is made of the few best practices so far implemented in favor of some Sicilian wetlands, aimed at their dynamic protection and enhancement, and the concrete possibility of restoring some of the most interesting ghost ponds

VR Technologies in Cultural Heritage

This open access book constitutes the refereed proceedings of the First International Conference on VR Technologies in Cultural Heritage, VRTCH 2018, held in Brasov, Romania in May 2018. The 13 revised full papers along with the 5 short papers presented were carefully reviewed and selected from 21 submissions. The papers of this volume are organized in topical sections on data acquisition and modelling, visualization methods / audio, sensors and actuators, data management, restoration and digitization, cultural tourism

Crossing the glass transition during volcanic eruptions

Predicting the occurrence and the evolving nature of volcanic eruptions remains an outstanding challenge. The complexity of volcanic Systems requires the use of many different approaches to gain a more profound understanding of the interplay of parameters such as magma temperature, composition, volatile content, cooling rate and viscosity as they interactively control the rheology of magma. This study focusses on three different scenarios in which the glass transition, a kinetic boundary distinguishing between solid-like and liquid-like behavior of melt in response to applied stresses, is crossed. (1) Bubbly magma fragments due to rapid decompression. The yield strength of the magma is overcome and the magma behaves in a brittle manner. Here, the influence of permeable gas flow, inside porous and permeable rocks, on the speed at which magma fragmentation occurs was investigated experimentally. (2) Spatter from a lava fountain agglutinates and coalesces upon landing. A spatter-fed flow forms, progressively thickens and lengthens, and results in a complex accumulation of glassy layers mingled with scoria, which grades into a lava-like section at the front of the flow. Because it is likely that individual layers forming the spatter-fed flow remain in the glass Transition interval for extended periods of time, the effect of thermal annealing on glasses was tested. Conditions conducive to thermal annealing during emplacement are discussed. (3) A pyroclastic deposit is emplaced in a hot and viscous state via fall or flow processes and consists of vitrified material and obsidian. The eruptive scenario is unclear; here the cooling history as well as microscopic and macroscopic textures help constraining the nature of the deposit’s components and identify the last few processes by which this deposit was emplaced. Permeable flow of volatiles through the porous and permeable network of a bubbly magma may influence the speed of magma fragmentation. Experiments were performed to reproduce the fragmentation of magma using a shock tube apparatus at room temperature and natural pyroclastic material with a connected porosity ranging from 15% to 78%. For each sample series, the initial pressure required to initiate Magma fragmentation was determined. Furthermore, sample permeability was measured and the samples were classified into: (a)dome/conduit wall rocks and (b) pumice/scoria. Results confirm that substantial outgassing during fragmentation leads to higher fragmentation thresholds. In addition, experimental fragmentation speeds are unexpectedly significantly higher than the modeled fragmentation speeds for high-permeability dome/conduit wall rocks, but lower for high-permeability pumices. Low-porosity, low-permeability, altered dome/conduit wall rocks fragment at significantly higher speeds than expected. Because fragmentation threshold and fragmentation viii speed are among the determining parameters for the initiation, sustainment and cessation of an eruption, outgassing should be considered in the modeling of magma fragmentation dynamics. The spatter-fed rheomorphic deposit from Cala di Tramontana, on the island of Pantelleria, Sicily, resulted from the mildly explosive eruption of pantelleritic magma as a lava fountain. This peralkaline rhyolitic magma has exceptionally low viscosities due to its high alkali, halogen and iron contents. Microscopic textural, geochemical and thermal analyses have helped setting better constraints on the cooling history and emplacement of this ca. 7 m thick deposit. Peak glass transition temperatures from the glassy layers are very low and range from 512 to 571 °C for a heating rate of 10 K min-1. Cooling rate estimates are obtained from the modeling of heat capacity curves using the enthalpy relaxation geospeedometry method, which follows the Tool-Narayanaswamy-Moynihan (TNM) method. Cooling rates range from 10-1 to ca. 10-7 K min-1 and are dispersed inconsistently throughout the flow deposit. For the first time, the effect of thermal annealing on cooling rate estimates has been tested. Thermal annealing experiments on remelted pantelleritic glasses from the same flow reveal that cooling rate estimates can be reduced by up to 3 log units when the investigated glasses are maintained at 450 °C for 1 day Prior to the modeling with the TNM method. The individual layers most likely remained at temperatures high enough to cause thermal annealing by which additional relaxation of the glasses could occur. Results support an emplacement model in which several hot-melt layers were emplaced gradually in a complex aggradation process and provided heat to underlying layers to allow for thermal annealing within the glass transition interval. Caution is necessary when interpreting cooling rate estimates. The phonolitic glassy base of a sequence of pyroclastic deposits from the top of the Guajara Formation along the Las Cañadas caldera, Tenerife, in the Canary Islands, exhibits unusual textures that sparked our interest. The ca. 3 m thick volcanic deposit is mostly composed of obsidian with light-green material dispersed in the obsidian. A cooling rate profile from the base up to about the middle of the deposit suggests higher cooling rates at the base (10-3 K s-1) than in the middle of the deposit (10-6 K s-1). The textural analyses reveal that the green Phase is composed of welded and devitrified ash and geochemical data indicate that the Major element composition of the obsidian and the green phase is identical within the accuracy of the measurements. An additional convincing piece of evidence consists of fragments of the green phase that detached and moved a short distance from their probable original location. Based on this analysis, it is likely that a pyroclastic flow was emplaced, followed by partial devitrification during cooling as the melt, now obsidian, was still viscous

VR Technologies in Cultural Heritage

This open access book constitutes the refereed proceedings of the First International Conference on VR Technologies in Cultural Heritage, VRTCH 2018, held in Brasov, Romania in May 2018. The 13 revised full papers along with the 5 short papers presented were carefully reviewed and selected from 21 submissions. The papers of this volume are organized in topical sections on data acquisition and modelling, visualization methods / audio, sensors and actuators, data management, restoration and digitization, cultural tourism