Is the physical vacuum a preferred frame ?

It is generally assumed that the physical vacuum of particle physics should be characterized by an energy momentum tensor in such a way to preserve exact Lorentz invariance. On the other hand, if the ground state were characterized by its energy-momentum vector, with zero spatial momentum and a non-zero energy, the vacuum would represent a preferred frame. Since both theoretical approaches have their own good motivations, we propose an experimental test to decide between the two scenarios.Comment: 12 pages, no figure

First lattice evidence for a non-trivial renormalization of the Higgs condensate

General arguments related to ``triviality'' predict that, in the broken phase of $(\lambda\Phi^4)_4$ theory, the condensate re-scales by a factor $Z_{\phi}$ different from the conventional wavefunction-renormalization factor, $Z_{prop}$. Using a lattice simulation in the Ising limit we measure $Z_{\phi}=m^2 \chi$ from the physical mass and susceptibility and $Z_{prop}$ from the residue of the shifted-field propagator. We find that the two $Z$'s differ, with the difference increasing rapidly as the continuum limit is approached. Since $Z_{\phi}$ affects the relation of to the Fermi constant it can sizeably affect the present bounds on the Higgs mass.Comment: 10 pages, 3 figures, 1 table, Latex2

An alternative heavy Higgs mass limit

After commenting on the present value of the Higgs particle mass from radiative corrections, we explore the phenomenological implications of an alternative, non-perturbative renormalization of the scalar sector where the mass of the Higgs particle does not represent a measure of observable interactions at the Higgs mass scale. In this approach the Higgs particle could be very heavy, even heavier than 1 TeV, and remain nevertheless a relatively narrow resonance.Comment: 17 pages. Version accepted for publication in Journal of Physics

Discrete Particle Swarm Optimization for the minimum labelling Steiner tree problem

Particle Swarm Optimization is an evolutionary method inspired by the social behaviour of individuals inside swarms in nature. Solutions of the problem are modelled as members of the swarm which fly in the solution space. The evolution is obtained from the continuous movement of the particles that constitute the swarm submitted to the effect of the inertia and the attraction of the members who lead the swarm. This work focuses on a recent Discrete Particle Swarm Optimization for combinatorial optimization, called Jumping Particle Swarm Optimization. Its effectiveness is illustrated on the minimum labelling Steiner tree problem: given an undirected labelled connected graph, the aim is to find a spanning tree covering a given subset of nodes, whose edges have the smallest number of distinct labels

Novel antidiabetic drugs and cardiovascular risk: Primum non nocere

Aims Diabetes treatments aim at preventing undesirable metabolic effects of hyperglycemia and at preventing/reducing tissue damage, including cardiovascular (CV) events. For approval, novel diabetes drugs undergo early systematic investigation to assess CV safety. This review provides an updated analysis of the results of recent studies examining novel diabetes medications and CV outcomes. Data synthesis The new regulatory guidelines enforce adjudication of all CV events when testing novel diabetes drugs. Endpoints of CV mortality, myocardial infarction (MI), stroke and hospitalization for heart failure (HF) were included in the most recent clinical studies on novel antihyperglycemics. These are: the incretin mimetics glucagon-like peptide 1 (GLP-1) receptor agonists (GLP1-RA), the incretin enhancers dipeptidylpeptidase-4 (DPP-4) inhibitors (DPP4-I or gliptins), and the sodium-glucose cotransporter (SGLT2) inhibitors (SGLT2-I or gliflozins). The studies ELIXA and EXAMINE, testing lixisenatide and alogliptin, respectively, revealed non-inferiority versus placebo in terms of CV safety. The SAVOR-TIMI 53 results confirmed overall CV safety of saxagliptin, but raised a warning related to the increase in the risk of hospitalization for HF in the saxagliptin group. Recently, TECOS revealed a particularly favorable CV profile for sitagliptin while EMPA-REG showed a significant CV risk reduction in empagliflozin treated subjects. Ongoing studies will provide additional data on CV safety for other GLP1-RAs, DPP4-I and SGLT2-I. Conclusions Results of safety outcome studies focused on CV events, including HF and mortality for CV causes, are not homogeneous. A critical analysis of these studies may help cardiologists and diabetes specialists to adapt their therapeutic choices to individual patients

Parameters controlling stiffness and strength of artificially cemented soils

The treatment of soils with cement is an attractive technique when a project requires improvement of the local soil for the construction of subgrades for rail tracks, for roads, as a support layer for shallow foundations, and to prevent sand liquefaction. This paper advances understanding of the key parameters for the control of strength and stiffness of cemented soils by testing two soils with different gradings and quantifying the influence of porosity/cement ratio on both initial shear modulus (G(0)) and unconfined compressive strength (q(u)). It is shown that the porosity/cement ratio is an appropriate parameter to assess both the initial stiffness and the unconfined compressive strength of the soil-cement mixtures studied. Each soil matrix has a unique relationship for G(0)/q(u) against adjusted porosity/cement ratio, linking initial stiffness and strength

Mechanical Properties of Calcareous Fly Ash Stabilised Soil

Construction of any type of structure on clayey ground could be problematic due to the high swelling potential and/or low strength characteristics of the soil. This can lead to low stability or differential settlement of the ground. Many soil stabilization techniques have been proposed to prevent the uneven settlement and failure of the soil. Stabilization of soil with class C fly ash offers many advantages such as improving engineering caracteristics, being cost-effective and being environmentally friendly. Class C fly ash chemically reacts with clay which results in a more durable and stronger soil. It has been shown by various researchers that fly ash-stabilized soil is typically stiff and strong even though there is no available standard or guidelines for the use of fly ash in construction industry. This paper presents the results from a program of experimental research on stabilization of a fine-grained soil with fly ash. Laboratory experiments, including Atterberg limits, compaction, uniaxial, and consolidation tests, were conducted on samples of a clay soil with different percentages of fly ash. The results show that adding fly ash decreased the plasticity index, increased compressive strength, and decreased the swelling and compressibility index. The maximum dry density increased and optimum moisture content decreased with addition of over 5 % fly ash by dry weight of the soil.Turkish governmentEuropean Union Horizon 202