3,990 research outputs found

    Regional disparities and industrial structure: territorial capital and productivity in Italian firms

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    We investigate the role of Territorial Capital (TC) on the productivity of Italian firms, constructing indicators for eight dimensions of TC in a first attempt to capture a wide variety of regional resources. When imposing homogeneous TC effects on all firms, we find that technological, social, institutional, financial and infrastructure capital drive productivity. However, only technological and artistic capital contribute to reduce regional disparities. Across industries, financial capital and infrastructure increase productivity in companies operating in a wide range of sectors. Industrial policies should consider sectoral heterogeneity and North-South differences to effectively boost productivity performance

    Sex-determinants and their distribution in various populations of Musca domestica L. of Western Europe

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    SUMMARYThe distribution of sex-determinants in field populations ofMusca domestica domesticaL. was studied in 62 samples of flies collected at 53 sites (animal farms) between 1975 and 1981 in an area stretching North–South from Denmark (+ Iceland) to Sicily.Karyological observations and genetic analyses demonstrated the existence of three types of population along a latitudinal cline. Populations of Northern Europe were of the standard type (XXfemales andXYmales) with theYchromosome determining sex. Those of Central and Southern Italy from sites below 100 m.a.s.l. (metres above sea level) were autosomal (XXfemales and males), sex in them being determined by autosomal sex-determinants for both femaleness and maleness. In the large intermediate zone the populations were mixed and had several karyotypes in both sexes. In this zone an altitudinal gradient was also observed, with autosomal determinants less common at higher altitudes. Genetic tests showed, in the autosomal and in the mixed populations, the presence of two autosomal male factors:MIII, the most common, on autosome III andMII, on autosome II.The gradient in sex determinants found in flies of Western Europe appears to be a dynamic phenomenon of relatively recent origin. Both climatic influence and selective pressure with insecticides have probably contributed towards the micro-evolution of populations with different sex-determinants in the houseflies of the area studied

    Mitotic recombination in Musca domestica L. and its influence on mosaicism, gynandromorphism and recombination in males

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    SUMMARYIn the housefly, mosaics appear spontaneously but rarely. Sexual mosaics or gynandromorphs also appear in strains in which sex determination is based on autosomal sex factors. Rare cases of recombination in the male have been reported by some authors. In field and laboratory populations, mitotic plates with figures indicating exchange of chromatid segments are regularly observed in tissues of individuals of both sexes and at all stages of development. All these anomalies are interpreted as outward manifestation of the same phenomenon: mitotic recombination. The cytological basis of mitotic recombination, its relative frequency, its influence on linkage and genetic variability are discussed

    A TGA/FT-IR study for OC and EC quantification applied to carbonaceous aerosol collected in Milan (Italy)

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    International audienceCarbon analysis consists in the evaluation of the carbonaceous content of the aerosol (TC) but, more importantly, of its distribution between the two components EC (Elemental Carbon) and OC (Organic Carbon) that are characterized by different physical-chemical properties. In spite of the numerous studies focused on this topic, nowadays, a universal methodology for the determination of the two components EC and OC is not available. In fact OC and EC (also known as black carbon or soot) are operationally defined by the method of analysis and, as a consequence, different methods can produce different results. In this paper we present results on the application of TGA/FT-IR (Thermogravimetric Analysis/Fourier Transformed Infrared Spectroscopy) to the characterization of carbonaceous aerosols. The analytical methodology was applied to PM10 four-hour time resolution samples collected in Milan urban area. The method is a two-steps thermal one and bases itself on the different thermal behaviour of OC and EC. It has been set up analyzing suitable standards containing both organic and elemental carbon. Carbon quantification is achieved by on-line, continuous monitoring of CO2 infrared absorption at 2361 cm?1. A good separation between OC and EC on particulate matter samples has been obtained. Ranges and average values were respectively 12?70 ”g/m3 and 20 ”g/m3 for OC and 0.2?6 ”g/m3 and 2 ”g/m3 for EC. On average OC and EC made up respectively 29.3 (±12.8) % and 2.5 (±1.8) % of PM10 fraction. The method reliability has been verified by comparison with TOT (Thermal Optical Transmission) technique. OC and EC values determined for ambient samples of PM10 were also correlated with meteorological parameters as well as with Radon concentrations

    Shall we dance? Recreational dance, well-being and productivity performance during COVID-19: a three-country study

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    Mental health issues are increasingly prevalent worldwide, emphasizing the need to research antecedents and consequences of well-being. Prior research shows that within organizations, higher levels of subjective well-being (SWB) promote productivity performance. Building on this research, the authors hypothesize that recreational dance positively influences productivity through higher SWB. Survey data from Brazil, Italy, and the United Kingdom reveal that recreational dancers are more productive than nondancers due to their higher intrinsic motivation and SWB. Dancing has an additional direct effect on productivity, beyond the mediating role of SWB. The results indicate well-being and productivity improvements in all three countries, although they show a moderating effect such that the relationship between recreational dance and SWB is stronger when social norms are perceived to be looser. This study indicates potentially far-reaching benefits that could be achieved by including recreational dance in corporate well-being programs. International dance organizations could market dance classes as a pathway to increase productivity at work and explore synergies with public health marketing to promote the benefits of recreational dance in joint international campaigns

    A new look at the cosmic ray positron fraction

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    The positron fraction in cosmic rays was found to be a steadily increasing in function of energy, above ∌\sim 10 GeV. This behaviour contradicts standard astrophysical mechanisms, in which positrons are secondary particles, produced in the interactions of primary cosmic rays during the propagation in the interstellar medium. The observed anomaly in the positron fraction triggered a lot of excitement, as it could be interpreted as an indirect signature of the presence of dark matter species in the Galaxy. Alternatively, it could be produced by nearby astrophysical sources, such as pulsars. Both hypotheses are probed in this work in light of the latest AMS-02 positron fraction measurements. The transport of the primary and secondary positrons in the Galaxy is described using a semi-analytic two-zone model. MicrOMEGAs is used to model the positron flux generated by dark matter species. The description of the positron fraction from astrophysical sources is based on the pulsar observations included in the ATNF catalogue. We find that the mass of the favoured dark matter candidates is always larger than 500 GeV. The only dark matter species that fulfils the numerous gamma ray and cosmic microwave background bounds is a particle annihilating into four leptons through a light scalar or vector mediator, with a mixture of tau (75%) and electron (25%) channels, and a mass between 0.5 and 1 TeV. The positron anomaly can also be explained by a single astrophysical source and a list of five pulsars from the ATNF catalogue is given. Those results are obtained with the cosmic ray transport parameters that best fit the B/C ratio. Uncertainties in the propagation parameters turn out to be very significant. In the WIMP annihilation cross section to mass plane for instance, they overshadow the error contours derived from the positron data.Comment: 20 pages, 16 figures, accepted for publication in A&A, corresponds to published versio

    Multitrace deformations, Gamow states, and Stability of AdS/CFT

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    We analyze the effect of multitrace deformations in conformal field theories at leading order in a large N approximation. These theories admit a description in terms of a weakly coupled gravity dual. We show how the deformations can be mapped into boundary terms of the gravity theory and how to reproduce the RG equations found in field theory. In the case of doubletrace deformations, and for bulk scalars with masses in the range −d2/4<m2<−d2/4+1-d^2/4<m^2<-d^2/4+1, the deformed theory flows between two fixed points of the renormalization group, manifesting a resonant behavior at the scale characterizing the transition between the two CFT's. On the gravity side the resonance is mapped into an IR non-normalizable mode (Gamow state) whose overlap with the UV region increases as the dual operator approaches the free field limit. We argue that this resonant behavior is a generic property of large N theories in the conformal window, and associate it to a remnant of the Nambu-Goldstone mode of dilatation invariance. We emphasize the role of nonminimal couplings to gravity and establish a stability theorem for scalar/gravity systems with AdS boundary conditions in the presence of arbitrary boundary potentials and nonminimal coupling.Comment: 14 pages, references added, introduction change

    The deepest X-ray look at the Universe

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    The origin of the X-ray background, in particular at hard (2-10 keV) energies, has been a debated issue for more than 30 years. The Chandra deep fields provide the deepest look at the X-ray sky and are the best dataset to study the X-ray background. We searched the Chandra Deep Field South for X-ray sources with the aid of a dedicated wavelet-based algorithm. We are able to reconstruct the Log N-Log S source distribution in the soft (0.5-2 keV) and hard (2-10 keV) bands down to limiting fluxes of 2x10^{-17} erg s^{-1} cm^{-2} and 2x10^{-16} erg s^{-1} cm^{-2}, respectively. These are a factor ~5 deeper than previous investigations. We find that the soft relation continues along the extrapolation from higher fluxes, almost completely accounting for the soft X-ray background. On the contrary, the hard distribution shows a flattening below ~2x10^{-14} erg s^{-1} cm^{-2}. Nevertheless, we can account for >68% of the hard X-ray background, with the main uncertainty being the sky flux itself.Comment: Accepted for publication on ApJL. Two figures, requires emulateapj5 (included
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