Grazing impact on soil chemical and biological properties under different plant cover types in a mountain area of Southern Italy.

Grazing can contribute to soil degradation by compaction due to roaming of livestock and loss of herbaceous cover, affecting also soil microbial community. Aim of this study was to assess grazing impact on soil microbial community and nutrient status under different plant cover types (i.e., fernery, chestnut wood, garigue). Grazed and ungrazed soils were analysed for water holding capacity, pH, organic carbon, N, S, K, Mg, Fe, Mn, Zn and Cu content, microbial biomass, fungal mycelium and potential respiration. Moreover, some ecophysiological indices, as microbial quotient, coefficient of endogenous mineralization (CEM), metabolic quotient (qCO2) and fungal fraction of microbial carbon were calculated. The results of present study showed that a moderate intensity grazing had low or no impact on chemical characteristics of soils and affects microbial community mainly in grazed areas with lower vegetation cover and lower content of nutrient and organic carbon, compared to areas with a thick layer of vegetation

Real-time virtual sonography in gynecology & obstetrics. literature's analysis and case series

Fusion Imaging is a latest generation diagnostic technique, designed to combine ultrasonography with a second-tier technique such as magnetic resonance imaging and computer tomography. It has been mainly used until now in urology and hepatology. Concerning gynecology and obstetrics, the studies mostly focus on the diagnosis of prenatal disease, benign pathology and cervical cancer. We provided a systematic review of the literature with the latest publications regarding the role of Fusion technology in gynecological and obstetrics fields and we also described a case series of six emblematic patients enrolled from Gynecology Department of Sant ‘Andrea Hospital, “la Sapienza”, Rome, evaluated with Esaote Virtual Navigator equipment. We consider that Fusion Imaging could add values at the diagnosis of various gynecological and obstetrics conditions, but further studies are needed to better define and improve the role of this fascinating diagnostic tool

Flow curvature effects on dynamic behaviour of a novel vertical axis tidal current turbine: numerical and experimental analysis

The paper deals with performances analysis of vertical axis turbine to exploit tidal marine currents. Flow curvature effects on performences of a novel vertical axis turbine have been investuigated. It has been shown that the flow curvature effect allows to design properly an accurate airfoil shape to increase turbine performances

Statistics of the fractional polarisation of extragalactic dusty sources in Planck HFI maps

We estimate the average fractional polarisation at 143, 217 and 353 GHz of a sample of 4697 extragalactic dusty sources by applying stacking technique. The sample is selected from the second version of the Planck Catalogue of Compact Sources at 857 GHz, avoiding the region inside the Planck Galactic mask (fsky ~ 60 per cent). We recover values for the mean fractional polarisation at 217 and 353 GHz of (3.10 \pm 0.75) per cent and (3.65 \pm 0.66) per cent, respectively, whereas at 143 GHz we give a tentative value of (3.52 \pm 2.48) per cent. We discuss the possible origin of the measured polarisation, comparing our new estimates with those previously obtained from a sample of radio sources. We test different distribution functions and we conclude that the fractional polarisation of dusty sources is well described by a log-normal distribution, as determined in the radio band studies. For this distribution we estimate {\mu}_{217GHz} = 0.3 \pm 0.5 (that would correspond to a median fractional polarisation of {\Pi}_{med} = (1.3 \pm 0.7) per cent) and {\mu}_{353GHz} = 0.7 \pm 0.4 ({\Pi}_{med} = (2.0 \pm 0.8) per cent), {\sigma}_{217GHz} = 1.3 \pm 0.2 and {\sigma}_{353GHz} = 1.1 \pm 0.2. With these values we estimate the source number counts in polarisation and the contribution given by these sources to the CMB B-mode angular power spectrum at 217, 353, 600 and 800 GHz. We conclude that extragalactic dusty sources might be an important contaminant for the primordial B-mode at frequencies > 217 GHz.Comment: arXiv admin note: text overlap with arXiv:1703.0995

Second-order quantum nonlinear optical processes in single graphene nanostructures and arrays

Intense efforts have been made in recent years to realize nonlinear optical interactions at the single-photon level. Much of this work has focused on achieving strong third-order nonlinearities, such as by using single atoms or other quantum emitters while the possibility of achieving strong second-order nonlinearities remains unexplored. Here, we describe a novel technique to realize such nonlinearities using graphene, exploiting the strong per-photon fields associated with tightly confined graphene plasmons in combination with spatially nonlocal nonlinear optical interactions. We show that in properly designed graphene nanostructures, these conditions enable extremely strong internal down-conversion between a single quantized plasmon and an entangled plasmon pair, or the reverse process of second harmonic generation. A separate issue is how such strong internal nonlinearities can be observed, given the nominally weak coupling between these plasmon resonances and free-space radiative fields. On one hand, by using the collective coupling to radiation of nanostructure arrays, we show that the internal nonlinearities can manifest themselves as efficient frequency conversion of radiative fields at extremely low input powers. On the other hand, the development of techniques to efficiently couple to single nanostructures would allow these nonlinear processes to occur at the level of single input photons.Comment: 25 pages, 6 figure

The very faint hard state of the persistent neutron star X-ray binary SLX 1737-282 near the Galactic centre

We report on a detailed study of the spectral and temporal properties of the neutron star low mass X-ray binary SLX 1737-282, which is located only ~1degr away from Sgr A. The system is expected to have a short orbital period, even within the ultra-compact regime, given its persistent nature at low X-ray luminosities and the long duration thermonuclear burst that it has displayed. We have analysed a Suzaku (18 ks) observation and an XMM-Newton (39 ks) observation taken 7 years apart. We infer (0.5-10 keV) X-ray luminosities in the range 3-6 x10^35erg s-1, in agreement with previous findings. The spectra are well described by a relatively cool (kTbb = 0.5 keV) black body component plus a Comptonized emission component with {\Gamma} ~1.5-1.7. These values are consistent with the source being in a faint hard state, as confirmed by the ~ 20 per cent fractional root mean square amplitude of the fast variability (0.1 - 7 Hz) inferred from the XMM-Newton data. The electron temperature of the corona is >7 keV for the Suzaku observation, but it is measured to be as low as ~2 keV in the XMM-Newton data at higher flux. The latter is significantly lower than expected for systems in the hard state. We searched for X-ray pulsations and imposed an upper limit to their semi-amplitude of 2 per cent (0.001 - 7 Hz). Finally, we investigated the origin of the low frequency variability emission present in the XMM-Newton data and ruled out an absorption dip origin. This constraint the orbital inclination of the system to 65 degr unless the orbital period is longer than 11 hr (i.e. the length of the XMM-Newton observation).Comment: 7 pages, 4 figures, 1 table. Accepted for publication in MNRA

Hot Quark Matter with an Axial Chemical Potential

We analyze the phase diagram of hot quark matter in presence of an axial chemical potential, $\mu_5$. The latter is introduced to mimic the chirality transitions induced, in hot Quantum Chromodynamics, by the strong sphaleron configurations. In particular, we study the curvature of the critical line at small $\mu_5$, the effects of a finite quark mass and of a vector interaction. Moreover, we build the mixed phase at the first order phase transition line, and draw the phase diagram in the chiral density and temperature plane. We finally compute the full topological susceptibility in presence of a background of topological charge.Comment: 12 pages, 7 figures. Few references added, short discussion included. Final version appearing on Phys. Rev.