Ethnic Concentration, Cultural Identity and Immigrant Self-Employment in Switzerland

Immigrant self-employment rates vary considerably across regions in Switzerland. Business ownership provides an alternative to wage labour, where immigrants have to face structural barriers such as the limited knowledge of the local language, or difficulties in fruitfully making use of their own human capital. Despite their historically high unemployment rates with respect to natives, immigrants in Switzerland are less entrepreneurial. It is therefore important to uncover factors that may facilitate the transition from the status of immigrant to the one of economic agent. Among others factors, concentration in ethnic enclaves, as well as accumulated labour market experience and time elapsed since immigration, have been associated to higher business ownership rates. In this paper, we use a cross-section of 2,490 Swiss municipalities in order to investigate the role played by the ethnic concentration of immigrants, as well as cultural factors, in determining self-employment rates.

Directed transport of active particles over asymmetric energy barriers

We theoretically and numerically investigate the transport of active colloids to target regions, delimited by asymmetric energy barriers. We show that it is possible to introduce a generalized effective temperature that is related to the local variance of particle velocities. The stationary probability distributions can be derived from a simple diffusion equation in the presence of an inhomogeneous effective temperature resulting from the action of external force fields. In particular, transitions rates over asymmetric energy barriers can be unbalanced by having different effective temperatures over the two slopes of the barrier. By varying the type of active noise, we find that equal values of diffusivity and persistence time may produce strongly varied effective temperatures and thus stationary distributions

XMM-Newton observations of SNR 1987A. II. The still increasing X-ray light curve and the properties of Fe K lines

Aims. We report on the recent observations of the supernova remnant SNR 1987A in the Large Magellanic Cloud with XMM-Newton. Carefully monitoring the evolution of the X-ray light curve allows to probe the complex circumstellar medium structure observed around the supernova progenitor star. Methods. We analyse all XMM-Newton observations of SNR 1987A from January 2007 to December 2011, using data from the EPIC-pn camera. Spectra from all epochs are extracted and analysed in a homogeneous way. Using a multi-shock model to fit the spectra across the 0.2-10 keV band we measure soft and hard X-ray fluxes with high accuracy. In the hard X-ray band we examine the presence and properties of Fe K ines. Our findings are interpreted in the framework of a hydrodynamics-based model. Results. The soft X-ray flux of SNR 1987A continuously increased in the recent years. Although the light curve shows a mild flattening, there is no sudden break as reported in an earlier work, a picture echoed by a revision of the Chandra light curve. We therefore conclude that material in the equatorial ring and out-of-plane HII regions are still being swept-up. We estimate the thickness of the equatorial ring to be at least 4.5x10^16 cm (0.0146 pc). This lower limit will increase as long as the soft X-ray flux has not reached a turn-over. We detect a broad Fe K line in all spectra from 2007 to 2011. The widths and centroid energies of the lines indicate the presence of a collection of iron ionisation stages. Thermal emission from the hydrodynamic model does not reproduce the low-energy part of the line (6.4-6.5 keV), suggesting that fluorescence from neutral and/or low ionisation Fe might be present.Comment: 4 pages, 3 figures, 2 tables. Accepted for publication in Astronomy and Astrophysic

Bubbling with L2L^2-almost constant mean curvature and an Alexandrov-type theorem for crystals

A compactness theorem for volume-constrained almost-critical points of elliptic integrands is proven. The result is new even for the area functional, as almost-criticality is measured in an integral rather than in a uniform sense. Two main applications of the compactness theorem are discussed. First, we obtain a description of critical points/local minimizers of elliptic energies interacting with a confinement potential. Second, we prove an Alexandrov-type theorem for crystalline isoperimetric problems

Los hombres serios ríen (La argumentación en un texto de Freud)

Así como en los sueños podemos diferenciar el contenido latente del contenido manifiesto, pero teniendo en cuenta que se condicionan mutuamente y se pasa de uno a otro por medio del trabajo del sueño o del análisis, partimos en el presente trabajo de la distinción establecida por Aristóteles entre la dialéclica, que hace uso del "lagos" y la retórica que emplea "ethos" y "pathos”. Pero pensamos con Marcello Pera que la primera no puede separarse de la segunda

The essential oil of Thymbra capitata and its application as a biocide on stone and derived surfaces

Many chemicals used nowadays for the preservation of cultural heritage pose a risk to both human health and the environment. Thus, it is desirable to find new and eco-friendly biocides that can replace the synthetic ones. In this regard, plant essential oils represent effective alternatives to synthetic substances for the preservation of historical monuments. Thymbra capitata (syn. Thymus capitatus) is a medicinal and aromatic plant growing in the Mediterranean area and endowed with important pharmacological properties related to its essential oil. Among them, the antimicrobial ones make the T. capitata essential oil an ideal candidate for industrial applications; for instance, as biocide for the inhibition and elimination of biological patinas of cyanobacteria and green algae on historical monuments. In the present work, we studied the chemical composition of the essential oil from T. capitata growing in Malta by gas chromatography-mass spectrometry (GC/MS). The major volatile component is the phenolic monoterpene carvacrol (73.2%), which is capable of damaging the cytoplasmic membrane and to interfere both in the growth curve and in the invasive capacity, though the contribution of minor components γ-terpinene and p-cymene cannot be disregarded. For the oil application on the stone surface, Pickering emulsions systems were prepared with an essential oil/water 1:3 mass ratio stabilized with kaolinite at 4 mass% in the presence of Laponite®; this allowed to limit the fast volatility of the oil and guaranteed a better application and an easier removal from the artefacts attacked by biodeteriogens both indoor and outdoor. This formulation caused the elimination of biodeteriogens from treated surfaces without residuals or films on artworks surface, and the effect was retained up to four months

Identification of onosma visianii roots extract and purified shikonin derivatives as potential acaricidal agents against tetranychus urticae

There is an increasing need for the discovery of reliable and eco-friendly pesticides and natural plant-derived products may play a crucial role as source of new active compounds. In this research, a lipophilic extract of Onosma visianii roots extract containing 12% of shikonin derivatives demonstrated significant toxicity and inhibition of oviposition against Tetranychus urticae mites. Extensive chromatographic separation allowed the isolation of 11 naphthoquinone derivatives that were identified by spectral techniques and were tested against Tetranychus urticae. All the isolated compounds presented effects against the considered mite and isobutylshikonin (1) and isovalerylshikonin (2) were the most active, being valuable model compounds for the study of new anti-mite agents