Calculating the mass fraction of primordial black holes

We reinspect the calculation for the mass fraction of primordial black holes (PBHs) which are formed from primordial perturbations, finding that performing the calculation using the comoving curvature perturbation c in the standard way vastly overestimates the number of PBHs, by many orders of magnitude. This is because PBHs form shortly after horizon entry, meaning modes significantly larger than the PBH are unobservable and should not affect whether a PBH forms or not - this important effect is not taken into account by smoothing the distribution in the standard fashion. We discuss alternative methods and argue that the density contrast, Δ, should be used instead as super-horizon modes are damped by a factor k2. We make a comparison between using a Press-Schechter approach and peaks theory, finding that the two are in close agreement in the region of interest. We also investigate the effect of varying the spectral index, and the running of the spectral index, on the abundance of primordial black holes

Different carbohydrate sources affect swine performance and post-prandial glycaemic response

The type of starch and fibre in the diet affects several parameters, including glycaemic and insulin response, that are involved in pig growth performance. Four experimental diets for growing pigs differing for carbohydrates source (corn, barley, faba bean and pea) were tested. The diets were analysed in vitro to assess the carbohydrates characteristics, and they were administered to 56 crossbreed growing pigs (Landrace × Large White) randomly divided into four groups (mean age of 95 ± 6 days; body weight 80 kg ± 4 days). Clinical examination and average daily gain were performed before recruitment and after 40 days of experiment. The metabolic effects were investigated by blood count and serum biochemical parameters and by the glycaemic and insulin post-prandial response. The study revealed substantial differences among the diets, suggesting that alternative feedstuffs for swine affect several parameters, including glycaemic and insulin response, with no negative effects on growing performance. The Barley group showed the highest daily weight gain (p <.05) associated with the highest glycaemic (p <.05) and insulin response at 1 and 2 h post-prandial (p <.01), suggesting that the barley-based diet can support performance comparable to that of the corn-based diet in growing pig. By contrast, the lowest glycaemia was observed in the Faba bean group (p <.05), confirming the capacity of this legume to modulate post-prandial glucose levels. Moreover, the ability of some ingredients in lowering glucose and insulin response enriches the knowledge on functional nutrients for animal diets and to prevent the incidence of enteric diseases.Highlights The type of starch and fibre used in the diet highly affected some blood parameters, such as glycaemic and insulin responses. The Barley group showed the highest daily weight gain. Lower glycaemia levels were observed in the Faba bean group compared to the Corn one. Alternative protein sources for swine diets can limit the glycaemic and insulin response with no negative effects on growing performance

Signatures of non-gaussianity in the isocurvature modes of primordial black hole dark matter

Primordial black holes (PBHs) are black holes which may have formed very early on during the radiation dominated era in the early universe. We present here a method by which the large scale perturbations in the density of primordial black holes may be used to place tight constraints on non-gaussianity if PBHs account for dark matter (DM). The presence of local-type non-gaussianity is known to have a significant effect on the abundance of primordial black holes, and modal coupling from the observed CMB scale modes can significantly alter the number density of PBHs that form within different regions of the universe, which appear as DM isocurvature modes. Using the recent \emph{Planck} constraints on isocurvature perturbations, we show that PBHs are excluded as DM candidates for even very small local-type non-gaussianity, $|f_{NL}|\approx0.001$ and remarkably the constraint on $g_{NL}$ is almost as strong. Even small non-gaussianity is excluded if DM is composed of PBHs. If local non-Gaussianity is ever detected on CMB scales, the constraints on the fraction of the universe collapsing into PBHs (which are massive enough to have not yet evaporated) will become much tighter.Comment: 23 pages, 11 figures. V2: minor corrections and changes, matches published versio

Critical Phenomena in Neutron Stars I: Linearly Unstable Nonrotating Models

We consider the evolution in full general relativity of a family of linearly unstable isolated spherical neutron stars under the effects of very small, perturbations as induced by the truncation error. Using a simple ideal-fluid equation of state we find that this system exhibits a type-I critical behaviour, thus confirming the conclusions reached by Liebling et al. [1] for rotating magnetized stars. Exploiting the relative simplicity of our system, we are able carry out a more in-depth study providing solid evidences of the criticality of this phenomenon and also to give a simple interpretation of the putative critical solution as a spherical solution with the unstable mode being the fundamental F-mode. Hence for any choice of the polytropic constant, the critical solution will distinguish the set of subcritical models migrating to the stable branch of the models of equilibrium from the set of subcritical models collapsing to a black hole. Finally, we study how the dynamics changes when the numerically perturbation is replaced by a finite-size, resolution independent velocity perturbation and show that in such cases a nearly-critical solution can be changed into either a sub or supercritical. The work reported here also lays the basis for the analysis carried in a companion paper, where the critical behaviour in the the head-on collision of two neutron stars is instead considered [2].Comment: 15 pages, 9 figure

Black hole production in tachyonic preheating

We present fully non-linear simulations of a self-interacting scalar field in the early universe undergoing tachyonic preheating. We find that density perturbations on sub-horizon scales which are amplified by tachyonic instability maintain long range correlations even during the succeeding parametric resonance, in contrast to the standard models of preheating dominated by parametric resonance. As a result the final spectrum exhibits memory and is not universal in shape. We find that throughout the subsequent era of parametric resonance the equation of state of the universe is almost dust-like, hence the Jeans wavelength is much smaller than the horizon scale. If our 2D simulations are accurate reflections of the situation in 3D, then there are wide regions of parameter space ruled out by over-production of black holes. It is likely however that realistic parameter values, consistent with COBE/WMAP normalisation, are safetly outside this black hole over-production region.Comment: 6pages, 7figures, figures correcte

Nutritional management of search and rescue dogs

Dogs used for search and rescue (SAR) may experience continuous micro-traumas that predispose them to skeletal disorders. The aim of the present study was to evaluate the effect of diet on osteo-articular apparatus in healthy SAR dogs. A total of sixteen SAR dogs were divided into two groups (low supplementation (LS) and high supplementation (HS)) and were fed for 3 months with two experimental diets, characterised by the same protein and energy density, but different inn-3 PUFA (6·2v. 8·4 % of metabolisable energy), chondroitin sulfate (219·8v. 989·0 mg/kg DM) and glucosamine (769·2v. 1318·7 mg/kg DM) in the LS and HS groups, respectively. At recruitment all dogs showed no joint inflammation signs, except four that showed mild symptoms. Haematology and serum biochemistry were performed every 30 d. Joint status was scored by physical and lameness evaluations. The sampling effect analysis showed potential beneficial effects by a decrease in a specific marker of membrane integrity (creatine kinase; CK). Comparing groups, glucose was significantly higher and CK was significantly lower in the HS group; however, in both cases the levels of these parameters fell in the normal range. At the end of the experiment, erythrocytes, Hb and packed cell volume were significantly higher in the HS compared with the LS group. These could result in an improvement in dogs' performance, even if this aspect was not investigated in the present study. Concerning joint evaluation (pain on manipulation, lameness and range of motion), no statistically significant differences were detected between the groups and within the experimental period

In vitro fermentation and chemical characteristics of mediterranean by-products for swine nutrition

The purpose of the study is to determine the nutritional characteristics of some by-products derived from fruit juice and olive oil production to evaluate their use in pig nutrition. Five by-products of citrus fruit (three citrus fruit pulp and two molasses) and three by-products of olive oil (olive cake) obtained by different varieties are analysed for chemical composition. The fermentation characteristics are evaluated in vitro using the gas production technique with swine faecal inoculum. All the citrus by-products are highly fermentable, producing gas and a high amount of short-chain fatty acids. The fermentation kinetics vary when comparing pulps and molasses. Citrus fruit pulps show lower and slower fermentation rates than molasses. The olive oil by-products, compared to citrus fruits ones, are richer in NDF and ADL. These characteristics negatively affect all the fermentation parameters. Therefore, the high concentration of fiber and lipids represents a key aspect in the nutrition of fattening pigs. The preliminary results obtained in this study confirm that the use of by-products in pig nutrition could represent a valid opportunity the reduce the livestock economic cost and environmental impact

Reducing the data-deficiency of threatened European habitats: Spatial variation of sabellariid worm reefs and associated fauna in the Sicily Channel, Mediterranean Sea

Biogenic reefs, such as those produced by tube-dwelling polychaetes of the genus Sabellaria, are valuable marine habitats which are a focus of protection according to European legislation. The achievement of this goal is potentially hindered by the lack of essential empirical data, especially in the Mediterranean Sea. This study addresses some of the current knowledge gaps by quantifying and comparing multi-scale patterns of abundance and distribution of two habitat-forming species (Sabellaria alveolata and S. spinulosa) and their associated fauna along 190 km of coast on the Italian side of the Sicily Channel. While the abundance of the two sabellariids and the total number of associated taxa did not differ at any of the examined scales (from tens of centimetres to tens-100 of kilometres), the structure (composition in terms of both the identity and the relative abundance of constituting taxa) of the associated fauna and the abundance of several taxa (the polychaetes Eulalia ornata, Syllis pulvinata, S. garciai, Nereis splendida and Arabella iricolor, and the amphipods Apolochus neapolitanus, Tethylembos viguieri and Caprella acanthifera) varied among locations established ~50e100 km apart. Syllis pulvinata also showed significant variation between sites (hundreds of metres apart), analogously to the other syllid polychaetes S. armillaris and S. gracilis, the nereidid polychaete Nereis rava, and the amphipod Gammaropsis ulrici. The largest variance of S. spinulosa, of the structure of the whole associated fauna and of 56% of taxa analysed individually occurred at the scale of replicates (metres apart), while that of the dominant bio-constructor S. alveolata and of 25% of taxa occurred at the scale of sites. The remaining 19% and the total richness of taxa showed the largest variance at the scale of locations. Present findings contribute to meet a crucial requirement of any future effective protection strategy, i.e., identifying relevant scales of variation to be included in protection schemes aiming at preserving representative samples not only of target habitats and organisms, but also of the processes driving such variabilit