Effect of the dam’s feeding regimen on the meat quality of light suckling lambs

In order to verify the effect of the introduction of concentrates without GMO risk and at low aflatoxin risk in the diet of grazing milk ewes on the quanti-qualitative production of meat of their milk-fed light lambs, two trials were carried out - in Sicily, on 32 Comisana lambs, slaughtered at 49±4 days (trial 1); and in Sardinia, on 28 Sarda lambs, slaughtered at 31±4 days(trial 2) - comparing the following grazing dams’ feeding regimes: High stocking rate + Organic (barley – tickbean or pea) Concentrate (HO); High stocking rate + Conventional (maize-soybean) Concentrate (HC); Low stocking rate + Organic Concentrate (LO); Low stocking rate + Conventional Concentrate (LC). Lamb performances, carcass quality, meat colour and lipid content were not modified by dam’s feeding regimen. However, significant differences were observed in the fatty acid (FA) composition of the intramuscular fat of the older suckling lambs of trial 1. The main variation concerned n-3 polyunsaturated FAs and conjugated linoleic acids

Dynamics of the Number of Trades of Financial Securities

We perform a parallel analysis of the spectral density of (i) the logarithm of price and (ii) the daily number of trades of a set of stocks traded in the New York Stock Exchange. The stocks are selected to be representative of a wide range of stock capitalization. The observed spectral densities show a different power-law behavior. We confirm the $1/f^2$ behavior for the spectral density of the logarithm of stock price whereas we detect a $1/f$-like behavior for the spectral density of the daily number of trades.Comment: 3 pages, 3 figures, submitted to Physica

Photoionization of hydrogen by a chirped, short X-ray pulse in the presence of a laser field

The ionization of hydrogen by a chirped XUV pulse in the presence of a few cycle infrared laser pulse is investigated. It is found that the combined action of the chirped pulse and the laser eld brings about asymmetries in the photoelectron momentum distribution that may be exploited for obtaining information on both the chirp and XUV pulse duration

Volatility in Financial Markets: Stochastic Models and Empirical Results

We investigate the historical volatility of the 100 most capitalized stocks traded in US equity markets. An empirical probability density function (pdf) of volatility is obtained and compared with the theoretical predictions of a lognormal model and of the Hull and White model. The lognormal model well describes the pdf in the region of low values of volatility whereas the Hull and White model better approximates the empirical pdf for large values of volatility. Both models fails in describing the empirical pdf over a moderately large volatility range.Comment: 6 pages, 2 figure

Novel Silicon Photomultipliers suitable for Dual-Mirror Small-Sized Telescopes of the Cherenkov Telescope Array

Many of the characteristics of Silicon Photomultipliers (SiPMs), such as high Photon Detection Efficiency (PDE), are well matched to the requirements of the cameras of the Small-Sized Telescopes (SSTs) proposed for the Cherenkov Telescope Array. In fact, compared to a single mirror, the double mirror Schwarzschild Couder configuration provides a much better Point Spread Function over a large field of view. It allows better correction of aberrations at large off axis angles and facilitates the construction of compact telescopes. Moreover, the small plate scale of the dual-mirror SSTs allows the use of SiPM detectors despite their small pixel sizes. These sensors have two further advantages compared to the Photo Multipliers Tubes: the low cost and the possibility to observe in very high Night Sky Background (NSB) light level without any damage. However, one area in which SiPM performance has required improvement is Optical CrossTalk (OCT), where multiple avalanches are induced by a single impinging photon. OCT, coupled with the typical NSB rate of 25 MCnts/s per pixel during Cherenkov observations, can place severe constraints on the triggering capability of the cameras. This paper describes the performance of novel Low Voltage Reverse (LVR) 2nd and 3rd generation Multi Pixel Photon Counters manufactured by Hamamatsu Photonics. These are designed to have both enhanced PDE and reduced OCT. Two 7 x 7 mm2 S14520 LVR2 MPPCs with 75 um microcells are tested and compared with detectors of the same pixel size with 50 um microcells. A comparative analysis of a 3 x 3 mm2 S14520 LVR2 device and an S14520 LVR3 device is also carried out, demonstrating that the LVR3 gives better photon detection in the 240 380 nm wavelength range. Finally, the effect of an infrared filter on the OCT is analysed.Comment: 17 pages, 17 figures, 2 tables. Submit to NIM-A Jurna

Degree stability of a minimum spanning tree of price return and volatility

We investigate the time series of the degree of minimum spanning trees obtained by using a correlation based clustering procedure which is starting from (i) asset return and (ii) volatility time series. The minimum spanning tree is obtained at different times by computing correlation among time series over a time window of fixed length $T$. We find that the minimum spanning tree of asset return is characterized by stock degree values, which are more stable in time than the ones obtained by analyzing a minimum spanning tree computed starting from volatility time series. Our analysis also shows that the degree of stocks has a very slow dynamics with a time-scale of several years in both cases.Comment: 9 pages, 3 figure

Topology of correlation based minimal spanning trees in real and model markets

We present here a topological characterization of the minimal spanning tree that can be obtained by considering the price return correlations of stocks traded in a financial market. We compare the minimal spanning tree obtained from a large group of stocks traded at the New York Stock Exchange during a 12-year trading period with the one obtained from surrogated data simulated by using simple market models. We find that the empirical tree has features of a complex network that cannot be reproduced, even as a first approximation, by a random market model and by the one-factor model.Comment: 4 pages revtex, 4 figs, first 2 in colo