Higgsino dark matter in partly supersymmetric models

Models where supersymmetry (SUSY) is manifest only in a sector of the low-energy spectrum have been recently proposed as an alternative to the MSSM. In these models the electroweak scale is explained by a fine-tuning between different Higgs mass contributions (split-SUSY models), or by the localization of the Higgs sector in a point of an extra dimension where all the mass parameters are suppressed by the metric (partly-SUSY models). Therefore, the presence of a good dark matter candidate becomes the main motivation for (partial) low-energy SUSY. We study this issue in minimal frameworks where the higgsinos are the only light supersymmetric particles. Whereas in split-SUSY models the higgsino should have a mass around 1 TeV, we show that in partly-SUSY models the lightest higgsino could also be found below MW.Comment: 12 pages, 3 figures, version to appear in Phys. Rev.

On the criticality of inferred models

Advanced inference techniques allow one to reconstruct the pattern of interaction from high dimensional data sets. We focus here on the statistical properties of inferred models and argue that inference procedures are likely to yield models which are close to a phase transition. On one side, we show that the reparameterization invariant metrics in the space of probability distributions of these models (the Fisher Information) is directly related to the model's susceptibility. As a result, distinguishable models tend to accumulate close to critical points, where the susceptibility diverges in infinite systems. On the other, this region is the one where the estimate of inferred parameters is most stable. In order to illustrate these points, we discuss inference of interacting point processes with application to financial data and show that sensible choices of observation time-scales naturally yield models which are close to criticality.Comment: 6 pages, 2 figures, version to appear in JSTA

Evaluation of the material’s damage in gas turbine rotors by instrumented spherical indentation

Experimental indentations are carried out on items of two different materials, taken in severallocation of various components from high pressure gas turbine rotor which have seen an extensive service. Thecomponents object of investigation consisted in 1st and 2nd high pressure turbine wheels made in nickel-basesuperalloy (Inconel 718), the spacer ring (Inconel 718) and the compressor shaft made in CrMoV low alloy steel(ASTM A471 type10).Aim of the work is to set up the capability of the instrumented spherical indentation testing system to evaluatevariations in the material properties due to damage, resulting from temperature field and stresses acting oncomponents during service. To perform this task load-indentation depth curves will be acquired in variouszones of the above mentioned components. The analysis of the results has allowed to identify an energyparameter which shows a linear evolution with the mean temperature acting on the components

Financial correlations at ultra-high frequency: theoretical models and empirical estimation

A detailed analysis of correlation between stock returns at high frequency is compared with simple models of random walks. We focus in particular on the dependence of correlations on time scales - the so-called Epps effect. This provides a characterization of stochastic models of stock price returns which is appropriate at very high frequency.Comment: 22 pages, 8 figures, 1 table, version to appear in EPJ

Individual Rights, Economic Transactions, and Recognition: A Legal Approach to Social Economics

Modernity brought the idea of individual property rights as a com- plex phenomenon. However, economics adopted a simplistic view of property as a fundamental institution, understating the complex interaction of different rights and obligations that frame the legal environment of economic processes with an insufficiently elaborated tool. Here, a more elaborate view of legal elements will be propose

A thermostable salmonella phage endolysin, Lys68, with broad bactericidal properties against gram-negative pathogens in presence of weak acids

Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermo)stability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.This work was supported by the projects FCOMP-01-0124-FEDER-019446, FCOMP-01-0124-FEDER-027462 and PEst-OE/EQB/LA0023/2013 from "Fundacao para a Ciencia e Tecnologia" (FCT), Portugal. The authors thank the Project "BioHealth - Biotechnology and Bioengineering approaches to improve health quality", Ref. NORTE-07-0124-FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON. 2 - O Novo Norte), QREN, FEDER. Hugo Oliveira acknowledges the FCT grant SFRH/BD/63734/2009. Maarten Walmagh held a PhD scholarship of the IWT Vlaanderen. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Cosmic-ray knee and diffuse gamma, e+ and pbar fluxes from collisions of cosmic rays with dark matter

In models with extra dimensions the fundamental scale of gravity M_D could be of order TeV. In that case the interaction cross section between a cosmic proton of energy E and a dark matter particle \chi will grow fast with E for center of mass energies \sqrt{2m_\chi E} above M_D, and it could reach 1 mbarn at E\approx 10^9 GeV. We show that these gravity-mediated processes would break the proton and produce a diffuse flux of particles/antiparticles, while boosting \chi with a fraction of the initial proton energy. We find that the expected cross sections and dark matter densities are not enough to produce an observable asymmetry in the flux of the most energetic (extragalactic) cosmic rays. However, we propose that unsuppressed TeV interactions may be the origin of the knee observed in the spectrum of galactic cosmic rays. The knee would appear at the energy threshold for the interaction of dark matter particles with cosmic protons trapped in the galaxy by \muG magnetic fields, and it would imply a well defined flux of secondary antiparticles and TeV gamma rays.Comment: 19 pages, references added, version to appear in JCA

Physicians’ misperceived cardiovascular risk and therapeutic inertia as determinants of low LDL-cholesterol targets achievement in diabetes

Background: Greater efforts are needed to overcome the worldwide reported low achievement of LDL-c targets. This survey aimed to dissect whether and how the physician-based evaluation of patients with diabetes is associated with the achievement of LDL-c targets. Methods: This cross-sectional self-reported survey interviewed physicians working in 67 outpatient services in Italy, collecting records on 2844 patients with diabetes. Each physician reported a median of 47 records (IQR 42–49) and, for each of them, the physician specified its perceived cardiovascular risk, LDL-c targets, and the suggested refinement in lipid-lowering-treatment (LLT). These physician-based evaluations were then compared to recommendations from EAS/EASD guidelines. Results: Collected records were mostly from patients with type 2 diabetes (94%), at very-high (72%) or high-cardiovascular risk (27%). Physician-based assessments of cardiovascular risk and of LDL-c targets, as compared to guidelines recommendation, were misclassified in 34.7% of the records. The misperceived assessment was significantly higher among females and those on primary prevention and was associated with 67% lower odds of achieving guidelines-recommended LDL-c targets (OR 0.33, p < 0.0001). Peripheral artery disease, target organ damage and LLT-initiated by primary-care-physicians were all factors associated with therapeutic-inertia (i.e., lower than expected probability of receiving high-intensity LLT). Physician-suggested LLT refinement was inadequate in 24% of overall records and increased to 38% among subjects on primary prevention and with misclassified cardiovascular risk. Conclusions: This survey highlights the need to improve the physicians’ misperceived cardiovascular risk and therapeutic inertia in patients with diabetes to successfully implement guidelines recommendations into everyday clinical practice