The genericity theorem for the essential dimension of tame stacks

Let X be a regular tame stack. If X is locally of finite type over a field, we prove that the essential dimension of X is equal to its generic essential dimension; this generalizes a previous result of P. Brosnan, Z. Reichstein and the second author. Now suppose that X is locally of finite type over a 1-dimensional noetherian local domain R with fraction field K and residue field k. We prove that edk Xk ≤ edK XK if X → Spec R is smooth and edk Xk ≤ edK XK + 1 in general

Recent advances in the chemistry of metal carbamates

Following a related review dating back to 2003, the present review discusses in detail the various synthetic, structural and reactivity aspects of metal species containing one or more carbamato ligands, representing a large family of compounds across all the periodic table. A preliminary overview is provided on the reactivity of carbon dioxide with amines, and emphasis is given to recent findings concerning applications in various fields

Top Management Evaluation in Italian Food & Beverage Industry

The standard ISO 9001: 2015 “Quality Management System. Requirements” states that the success of a company’s quality certification system is closely linked to the quality of its top management. The aim of the present work is to develop a model of top management quality evaluation useful for the ends of this certification. The model is calibrated for the Italian Food & Beverage Industry and it follows a multidisciplinary approach. The evaluation model is formed by two parts. In the first, the quality of top management is associated with an estimate of the probability of default and the related average expected life of a company in the Italian Food & Beverage Industry. These parameters are calculated using an original, easy-to-apply methodology that is especially useful for small and medium-sized companies that do not have an official rating. The second part of the model provides a system to estimate the quality of top managers' management styles based on seven qualitative organizational variables, which are then summarized by the attribution of a score ranging from 1 to 10. The judgments formulated in the two parts of the model must be considered as a system to arrive at an integrated final evaluation

Non-precious metal carbamates as catalysts for the aziridine/CO2coupling reaction under mild conditions

The catalytic potential of a large series of easily available metal carbamates (based on thirteen different non-precious metal elements) was explored for the first time in the coupling reaction between 2-aryl-aziridines and carbon dioxide, working under solventless and ambient conditions and using tetraalkylammonium halides as co-catalysts. The straightforward synthesis of novel [NbCl3(O2CNEt2)2],NbCl, and [NbBr3(O2CNEt2)2],NbBr, is reported. The niobium complexNbCl, in combination with NBu4I, emerged as the best catalyst of the overall series to convert aziridines with smallN-alkyl substituents into the corresponding 5-aryl-oxazolidin-2-ones

The competitive productivity (CP) of tourism destinations: an integrative conceptual framework and a reflection on big data and analytics

Purpose: The purpose of this study is twofold. First, this study elaborates an integrative conceptual framework of tourism destination competitive productivity (TDCP) by blending established destination competitiveness frameworks, the competitive productivity (CP) framework and studies pertaining to big data and big data analytics (BDA) within destination management information systems and smart tourism destinations. Second, this study examines the drivers of TDCP in the context of the ongoing 4th industrial revolution by conceptualizing the destination business intelligence unit (DBIU) as a platform able to create sustained destination business intelligence under the guise of BDA, useful to support destination managers to achieve the tourism destination’s economic objectives. Design/methodology/approach: In this work, the authors leverage both extant literature (under the guise of research on CP, tourism destination competitiveness [TDC] and destination management information systems) and empirical work (in the form of interviews and field work involving destination managers and chief executive officers of destination management organizations and convention bureaus, as well as secondary data) to elaborate, develop and present an integrative conceptual framework of TDCP. Findings: The integrative conceptual framework of TDCP elaborated has been found helpful by a number of destination managers trying to understand how to effectively and efficiently manage and market a tourism destination in today’s fast-paced, digital and hypercompetitive environment. While DBIUs are at different stages of implementation, often as part of broader smart destination initiatives, it appears that they are increasingly fulfilling the purpose of creating sustained destination business intelligence by means of BDA to help tourism destinations achieve their economic goals. Research limitations/implications: This work bears several practical implications for tourism policymakers, destination managers and marketers, technology developers, as well as tourism and hospitality firms and practitioners. Tourism policymakers could embed TDCP into tourism and economic policies, and destination managers and marketers might build and make use of platforms such as the proposed DBIU. Technology developers need to understand that designing destination management information systems in general and more specifically DBIUs requires an in-depth analysis of the stakeholders that are going to contribute, share, control and use BDA. Originality/value: To the best of the authors’ knowledge, this study constitutes the first attempt to integrate the CP, TDC and destination management information systems research streams to elaborate an integrative conceptual framework of TDCP. Second, the authors contribute to the Industry 4.0 research stream by examining the drivers of tourism destination CP in the context of the ongoing 4th industrial revolution. Third, the authors contribute to the destination management information systems research stream by introducing and conceptualizing the DBIU and the related sustained destination business intelligence

Sistema di filologia computazionale per testi demotici

A project for a Demotic Inscriptions on Ostraka Database is being carried out in collaboration between ILC/CNR (Pisa), the Department of Electronic Engineering (Calabria University) and the Department of the Ancient World History (Egyptological section, Pisa University). The aim of the project is to analyse the digital colour images of demotic texts on ostraka (Medinet Madi, in Fayyum region) with the aid of computational tools. The module described in the paper is a neural component able to learn the graphical features of each demotic symbol, which has been previously segmented in the images thanks to a semiautomatic procedure. A specific neural network tries to recognize the text written in the images linking the symbols segmented within the ostraka images database to the correspondent symbols available on a virtual keyboard. The graphical interface is particularly useful for teaching and research activities on this type of archaeological documentation

Synthesis of α-alkylidene cyclic carbonatesviaCO2fixation under ambient conditions promoted by an easily available silver carbamate

The simple and cost-effective compound [Ag(O2CNEt2)], in combination with PPh3, works as an effective catalytic precursor in the carboxylation of propargyl alcohols at ambient temperature and atmospheric CO2pressure, and in most cases under solventless conditions. The silver carbamate revealed a better performance than commercial silver oxide, Ag2O, and allowed to obtain a series of α-alkylidene cyclic carbonates in high yields

Integrating Optical Wireless Communication Into an Optical Bifocal Metrology for Aerospace

Recently an innovative bifocal optical metrology method was proposed for space applications (e.g., rendez-vous and docking), based on unmodulated white LEDs. Here we design, realize, and test a solution that upgrades the metrology to include a digital communication feature, with no modification of the optical elements of the original system: indeed, the scheme exploits the same optical sources that are needed for metrology, which are now also working as optical antennas as their intensity is now modulated. At the receiver side, the conventional camera is now sided by a common photodiode. The system provides unidirectional data communication at 10 kbit/s speed. It is designed to support manoeuvres up to 400 m distance. The lab tests confirm the effectiveness of the proposed solutions, showing correct data transfer without any noticeable degradation of the metrology system

Diiron bis-cyclopentadienyl complexes as transfer hydrogenation catalysts: The key role of the bridging aminocarbyne ligand

The catalytic activity of a series of diiron complexes based on the {Fe2Cp2(CO)(x)} core (x = 2-3) and containing a bridging aminocarbyne ligand was screened in transfer hydrogenation reaction of cyclohexanone from isopropanol. The series includes cationic tricarbonyl complexes, [1a-d]CF3SO3, and neutral derivatives obtained by substitution of one carbonyl with hydride (2a-c), cyanide (3a-d) or chloride (4a) ligands. The novel compounds 2a-b, 3a-b and 4a were characterized by analytical and spectroscopic techniques, and the single crystal X-ray structure of one isomer of 4a was determined. In general, diiron complexes exhibited a moderate activity in combination with potassium hydroxide; [Fe2Cp2(CN)(CO)(mu-CO){mu-CN (Me)(4-C6H4OMe)}], 3a, emerged as the best catalyst, and the study of its activity was extended to a range of other ketones. DFT calculations suggest an unusual carbyne-centred mechanism, and the better performance displayed by 3a is ascribable to the stabilizing effect provided by the cyanide co-ligand, which is experimentally supported by IR analyses

Bypassing the Inertness of Aziridine/CO2 Systems to Access 5-Aryl-2-Oxazolidinones: Catalyst-Free Synthesis Under Ambient Conditions

The development of sustainable synthetic routes to access valuable oxazolidinones via CO2 fixation is an active research area, and the aziridine/carbon dioxide coupling has aroused a considerable interest. This reaction features a high activation barrier and thus requires a catalytic system, and may present some other critical issues. Here, the straightforward gram-scale synthesis of a series of 5-aryl-2-oxazolidinones was developed at ambient temperature and atmospheric CO2 pressure, in the absence of any catalyst/co-catalyst. The key to this innovative procedure consists in the direct transfer of the pre-formed amine/CO2 adduct (carbamate) to common aziridine precursors (dimethylsulfonium salts), replacing the classical sequential addition of amine (intermediate isolation of aziridine) and then CO2. The reaction mechanism was investigated by NMR spectroscopy and DFT calculations applied to model cases