New technique to measure the cavity defects of Fabry-Perot interferometers

(Abridged): We define and test a new technique to accurately measure the cavity defects of air-spaced FPIs, including distortions due to the spectral tuning process typical of astronomical observations. We further develop a correction technique to maintain the shape of the cavity as constant as possible during the spectral scan. These are necessary steps to optimize the spectral transmission profile of a two-dimensional spectrograph using one or more FPIs. We devise a generalization of the techniques developed for the so-called phase-shifting interferometry to the case of FPIs. The technique is applicable to any FPI that can be tuned via changing the cavity spacing ($z$-axis), and can be used for any etalon regardless of the coating' reflectivity. The major strength of our method is the ability to fully characterize the cavity during a spectral scan, allowing for the determination of scan-dependent modifications of the plates. As a test, we have applied this technique to three 50 mm diameter interferometers, with cavity gaps ranging between 600 micron and 3 mm, coated for use in the visible range. We obtain accurate and reliable measures of the cavity defects of air-spaced FPIs, and of their evolution during the entire spectral scan. Our main, and unexpected, result is that the relative tilt between the two FPI plates varies significantly during the spectral scan, and can dominate the cavity defects; in particular, we observe that the tilt component at the extremes of the scan is sensibly larger than at the center of the scan. Exploiting the capability of the electronic controllers to set the reference plane at any given spectral step, we develop a correction technique that allows the minimization of the tilt during a complete spectral scan. The correction remains highly stable over long periods, well beyond the typical duration of astronomical observations.Comment: 15 pages, 20+ figures, accepted for publication in A&A. Two additional movies are available in the online version of the pape

Solar Atmospheric Oscillations and the Chromospheric Magnetic Topology

We investigate the oscillatory properties of the quiet solar chromosphere in relation to the underlying photosphere, with particular regard to the effects of the magnetic topology. We perform a Fourier analysis on a sequence of line-of-sight velocities measured simultaneously in a photospheric (Fe I 709.0 nm) and a chromospheric line (Ca II 854.2 nm). The velocities were obtained from full spectroscopic data acquired at high spatial resolution with the Interferometric BIdimensional Spectrometer (IBIS). The field of view encompasses a full supergranular cell, allowing us to discriminate between areas with different magnetic characteristics. We show that waves with frequencies above the acoustic cut-off propagate from the photosphere to upper layers only in restricted areas of the quiet Sun. A large fraction of the quiet chromosphere is in fact occupied by ``magnetic shadows'', surrounding network regions, that we identify as originating from fibril-like structures observed in the core intensity of the Ca II line. We show that a large fraction of the chromospheric acoustic power at frequencies below the acoustic cut-off, residing in the proximity of the magnetic network elements, directly propagates from the underlying photosphere. This supports recent results arguing that network magnetic elements can channel low-frequency photospheric oscillations into the chromosphere, thus providing a way to input mechanical energy in the upper layers.Comment: 4 pages, 3 figure, A&A Letters in pres

Foodora, Deliveroo & Co.: le fattispecie della gig-economy italiana, tra previsioni contrattuali ed effettive modalità di esecuzione del rapporto

Il paper analizza le fattispecie della gig economy presenti in Italia, con riferimento al settore della consegna immediata via app. Dopo aver passato in rassegna le caratteristiche delle principali piattaforme operative in Italia, il paper si sofferma sui contenuti dei contratti sottoscritti tra i fattorini e la piattaforma, di cui vengono esaminate le clausole principali. Il paper passa quindi a esaminare le concrete modalit\ue0 di esecuzione del rapporto, per verificare la tenuta delle c.d. independent contractor clauses contenute nei testi contrattuali. Nella parte conclusiva, vengono svolte alcune considerazioni giuridiche, de iure condito e de iure condendo, in merito alla necessit\ue0 di ripensare le tutele applicabili alle nuove forme di lavoro analizzate nel paper

Além da subordinação: os remédios de direito privado para os “trabalhadores digitais”

Private Law Protections for \u201cDigital Workers\u201d beyond Requalification \u2013 The paper aims to analyse the legal aspects of \u201cdigital work\u201d, as including \u201cwork on demand via app\u201d and \u201ccrowdwork\u201d, from the particular perspective of non-employment law regulations and standards. The breakout of digital work and the \u201ccommodification of labour\u201d jeopardise, together with labour law standards, also the truly founding idea that labour is not a commodity. Nonetheless, the \u201cchallenge\u201d of digital work may constitute an opportunity for further reflections on the development of protective schemes applicable to all human beings who work, regardless of the legal scheme under which they carry out their activities. In this perspective, the paper aims to verify whether it is useful and possible to search for some protective provisions for digital workers outside the domain of statutory employment law. To this end, after a brief description of the phaenomenon of \u201cdigital work\u201d and a comparison between Anglo-American case law and the less open-minded perspective of Italian Law, the paper will try to find out whether it is possible to elaborate some protective schemes for digital workers through the recourse to contract law and selfemployed work regulations. The paper will deal with some critical points (such as the possibility to refuse Amazon Mechanical Turkers\u2019 work without payment, or to \u201cdismiss\u201d an Uber driver for low reputational rates), in order to verify whether outside labour law it is possible to find some protection for digital workers, and, in the affirmative, to what extent. In the perspective of legislative intervention, the paper will focus on the Italian recent law on selfemployed non-entrepreneurial work, on the bill so-called Sharing Economy Act and on some the new provisions of the French Code du Travail. The conclusion will stress out that even moving outside the domain of statutory employment law it is possible to provide \u201cdigital workers\u201d with a certain degree of protection

The (Unbearable?) Lightness of Self-Employed Work Intermediation : The Cases of Uber, Foodora and Amazon Mechanical Turk in the Light of the Italian Labour Law

The article aims to analyse the legal aspects of \u201cdigital work\u201d, as including \u201cwork on demand via app\u201d and \u201ccrowdwork\u201d, involving, respectively, an \u201con-demand mobile workforce\u201d and an \u201con-demand virtual workforce\u201d. The breakout of digital work and the \u201ccommodification of labour\u201d jeopardise, together with labour law standards, also the truly founding idea that labour is not a commodity. Nonetheless, the \u201cchallenge\u201d of digital work may constitute an opportunity for further reflections on the development of protective schemes applicable to all human beings who work, regardless of the legal scheme under which they carry out their activities. To verify whether it is useful and possible to search for some protective provisions for digital workers outside statutory employment law, the article will compare the recent developments of Anglo-American literature and case law with the less open-minded perspective of Italian Law. The artcile will therefore propose try to find out whether it is possible to elaborate some protective schemes for digital workers through the recourse to contract law and self-employed work regulations. Under such regulations, the article will deal with some critical points (such as the possibility to refuse Amazon Mechanical Turkers\u2019 work without payment, or to \u201cdismiss\u201d an Uber driver for low reputational rates), in order to verify whether outside labour law it is possible to find some protection for digital workers, and, in the affirmative, to what extent

I confini dell’impresa nella disciplina dei licenziamenti collettivi

L'A. analizza i tratti caratterizzanti delle articolazioni minori dell'impresa e sulla loro attitudine a fungere da referente per l'applicazione di diverse discipline lavoristiche, soffermandosi sulle conclusioni divergenti raggiunte dalla giurisprudenza europea e da quella nazionale

The (Unbearable?) Lightness of Self-Employed Work Intermediation

The paper analyses, from a juridical perspective, the classificatory schemes able to comprehend the vast spectrum of phaenomena labelled as \u201cdigital work\u201d, as including crowdsourcing and online intermediation of non-digital activities ("work on demand via app"). Both these activities are difficult to fit within the notion of employment dependency as developed by Labour Law in the last century. Safe for pathological cases, digital workers shall be deemed self-employed workers, since they are not legally bound to perform any activity. The paper will therefore try to classify digital work under the triangular scheme of \u201cintermediation of autonomous work\u201d, and will try to individuate whether it is possible to search for some protective provisions applicable to "digital" workers outside the field of statutory employment law

Anatomy of the supraventricular crest in human hearts

The supraventricular crest is a fleshy trabecula of the right ventricle that has an important function in guiding the blood flow. However, controversy persists regarding its anatomical constitution. In this study, we aimed to investigate its frequency, formation, termination, morphometry, and relationships with the septomarginal trabecula, septal papillary muscle, right atrioventricular ring, and left posterior semilunar valve of the pulmonary trunk valve. Our material consisted of 50 hearts from adult individuals of both sexes that had been preserved in 10% formalin. They were opened along the arterial cone by means of an incision starting at the pulmonary trunk and ending at the right margin. The supraventricular crest was always present. The marginal (right) extremity was formed by two to six muscle bundles that joined together (88%). On the septal (left) side, the single muscle bundle penetrated the interventricular septum directly (88%) or by means of two or three divisions (12%). It could form a septal band (52%) and could pass over the septal papillary muscle (43.5%) or just below it (34.8%). There was a relationship of muscle fibres between these two structures in 64% of cases. Dissection of the septal band demonstrated continuity with the septomarginal trabecula (46%). In 80% of cases, the crest was connected to the right atrioventricular ring and it participated in its outline directly (64%) or by means of muscle expansions (16%). Its muscle fibres bordered the left semilunar valve of the pulmonary valve in 50% of cases. Regarding morphometry, we observed that the length varied little with increasing weight of the heart (22.6%), but the height and width increased markedly with increasing weight of the heart. Folia Morphol 2010; 69, 1: 42-4

A knowledge-intensive approach to process similarity calculation

Process model comparison and similar processes retrieval are key issues to be addressed in many real world situations, and particularly relevant ones in some applications (e.g., in medicine), where similarity quantification can be exploited in a quality assessment perspective. Most of the process comparison techniques described in the literature suffer from two main limitations: (1) they adopt a purely syntactic (vs. semantic) approach in process activity comparison, and/or (2) they ignore complex control flow information (i.e., other than sequence). These limitations oversimplify the problem, and make the results of similarity-based process retrieval less reliable, especially when domain knowledge is available, and can be adopted to quantify activity or control flow construct differences. In this paper, we aim at overcoming both limitations, by introducing a framework which allows to extract the actual process model from the available process execution traces, through process mining techniques, and then to compare (mined) process models, by relying on a novel distance measure. The novel distance measure, which represents the main contribution of this paper, is able to address issues (1) and (2) above, since: (1) it provides a semantic, knowledge-intensive approach to process activity comparison, by making use of domain knowledge; (2) it explicitly takes into account complex control flow constructs (such as AND and XOR splits/joins), thus fully considering the different semantic meaning of control flow connections in a reliable way. The positive impact of the framework in practice has been tested in stroke management, where our approach has outperformed a state-of-the art literature metric on a real world event log, providing results that were closer to those of a human expert. Experiments in other domains are foreseen in the future

Comparative genome-wide analysis of repetitive DNA in the genus Populus L.

Genome skimming was performed, using Illumina sequence reads, in order to obtain a detailed comparative picture of the repetitive component of the genome of Populus species. Read sets of seven Populus and two Salix species (as outgroups) were subjected to clustering using RepeatExplorer (Novák et al. BMC Bioinformatics 11:378 2010). The repetitive portion of the genome ranged from 33.8 in Populus nigra to 46.5% in Populus tremuloides. The large majority of repetitive sequences were long terminal repeat-retrotransposons. Gypsy elements were over-represented compared to Copia ones, with a mean ratio Gypsy to Copia of 6.7:1. Satellite DNAs showed a mean genome proportion of 2.2%. DNA transposons and ribosomal DNA showed genome proportions of 1.8 and 1.9%, respectively. The other repeat types accounted for less of 1% each. Long terminal repeat-retrotransposons were further characterized, identifying the lineage to which they belong and studying the proliferation times of each lineage in the different species. The most abundant lineage was Athila, which showed large differences among species. Concerning Copia lineages, similar transpositional profiles were observed among all the analysed species; by contrast, differences in transpositional peaks of Gypsy lineages were found. The genome proportions of repeats were compared in the seven species, and a phylogenetic tree was built, showing species separation according to the botanical section to which the species belongs, although significant differences could be found within sections, possibly related to the different geographical origin of the species. Overall, the data indicate that the repetitive component of the genome in the poplar genus is still rapidly evolving