Ricci almost solitons

We introduce a natural extension of the concept of gradient Ricci soliton: the Ricci almost soliton. We provide existence and rigidity results, we deduce a-priori curvature estimates and isolation phenomena, and we investigate some topological properties. A number of differential identities involving the relevant geometric quantities are derived. Some basic tools from the weighted manifold theory such as general weighted volume comparisons and maximum principles at infinity for diffusion operators are discussed

Targeting Policies for Multidimensional Poverty and Social Fragility Relief Among Migrants in Italy, Using F-FOD Analysis

In this paper, we apply the novel Fuzzy First-Order Dominance (F-FOD) methodology to rank migrant subpopulations in Lombardy (Italy), in terms of multidimensional poverty and social fragility, for the year 2014, with the purpose to possibly provide useful support to policy-makers, in targeting relief interventions from poverty and discomfort. The F-FOD methodology allows for the direct comparison of different distributions of poverty and fragility, assessed by means of suitable ordinal multi-indicator systems, so extending to this more complex setting, the usual univariate first-order dominance criterion. It also provides complimentary “incomparability” scores, to assess to what extent the final rankings are reliable or instead forcing. It turns out that the levels of poverty and fragility of migrant subpopulations are quite different and, in particular, that the time since migrations has a key impact, on the identification of most critical cases, which typically involve recently migrated people. Evidence also emerges that the temporal poverty/fragility trajectories of migrants, distinguished by country of origin, follow different paths, suggesting how policy interventions must be properly, and differently, tuned to be effective

Low Energy Houses Heated By Biomass Boilers: Optimization Of The Heating System Control Strategy By Means Of Dynamic Simulation

The aim of this work is to analyze the energetic performance of a low energy house, situated in the region of Lower Austria (48° 11’ N, 15° 5’ E), by means of dynamic building simulation and on-site monitoring. According to the Austrian regulations, the annual heat demand of a low energy house is below 50 kWh•m2•yr-1. The building under study is a pre-fabricated house manufactured by an Austrian company. It has highly insulated walls made of lightweight materials and triple glazed windows. Indoor air quality is ensured by a ventilation system equipped with a heat recovery unit. The living space is heated by a 6 kW pellet boiler supplying hot water to a floor heating system. The house, inhabited by two people, is currently monitored in the frame of the BioMaxEff project, a European project aiming at the demonstration of biomass boilers in real life conditions. Parameters describing the boiler operation (water flow rate, inlet and outlet water temperature, pellet consumption etc.) as well as outdoor and indoor temperatures are registered continuously during the whole heating season. A coupled simulation of the building and its energy systems has been performed in a dynamic simulation environment (TRNSYS). First, the building envelope and the internal heat gains have been analyzed to calculate the annual heat demand, the annual peak load and the duration of the heating season. Second, the heating system has been added to simulation, including all its components and its control unit. The boiler has been simulated with the “Type 869” boiler model, which describes accurately the performance of pellet boilers. The model has been calibrated and validated with reference to laboratory data and successively integrated in the TRNSYS simulation. A new TRNSYS component has been programmed to simulate the heating system control unit, according to the specifications of the manufacturing company. Interviews with the house owner informed about the settings of the control strategy. Simulation results reveal that the boiler is slightly undersized and cannot completely fulfil the heat demand of the house. Moreover, the settings imposed in the heating system control unit are not adequate to maintain a comfortable indoor temperature during the whole day. These results have been confirmed by the data registered during on-site monitoring. To conclude the study, some improvements of the system control strategy have been proposed. In particular we suggest to adjust the system’s heating curve and the night setback temperature. By taking advantage of the thermal inertia of the floor heating system, the new control strategy improves the indoor comfort

Constraints on mediator-based dark matter and scalar dark energy models using √s = 13 TeV pp collision data collected by the ATLAS detector

Constraints on selected mediator-based dark matter models and a scalar dark energy model using up to 37 fb−1√s = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016 are summarised in this paper. The results of experimental searches in a variety of final states are interpreted in terms of a set of spin-1 and spin-0 single-mediator dark matter simplified models and a second set of models involving an extended Higgs sector plus an additional vector or pseudo-scalar mediator. The searches considered in this paper constrain spin-1 leptophobic and leptophilic mediators, spin-0 colour-neutral and colour-charged mediators and vector or pseudo-scalar mediators embedded in extended Higgs sector models. In this case, also √s = 8 TeV pp collision data are used for the interpretation of the results. The results are also interpreted for the first time in terms of light scalar particles that could contribute to the accelerating expansion of the universe (dark energy)

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

Light-by-light scattering (gamma gamma -> gamma gamma) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 mu b(-1) of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 +/- 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (gamma gamma) -> Pb-(center dot) + Pb-(center dot) gamma gamma, for photon transverse energy E-T > 3 GeV, photon absolute pseudorapidity vertical bar eta vertical bar < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 +/- 24 (stat.) +/- 17 (syst.) nb, which is in agreement with the standard model predictions

Measurements of W and Z boson production in pp collisions at √s = 5.02 TeV with the ATLAS detector

Measurements of fiducial integrated and differential cross sections for inclusive W+ , W− and Z boson production are reported. They are based on 25.0 ± 0.5pb−1 of pp collision data at √s=5.02 TeV collected with the ATLAS detector at the CERN Large Hadron Collider. Electron and muon decay channels are analysed, and the combined W+ , W− and Z integrated cross sections are found to be σW+=2266±9 (stat)±29 (syst)±43 (lumi) pb, σW−=1401±7 (stat)±18 (syst)±27 (lumi) pb, and σZ=374.5±3.4 (stat)±3.6 (syst)±7.0 (lumi) pb, in good agreement with next-to-next-to-leading-order QCD cross-section calculations. These measurements serve as references for Pb+Pb interactions at the LHC at √sNN=5.02 TeV

Measurement of the nuclear modification factor for inclusive jets in Pb+Pb collisions at √sNN=5.02 TeV with the ATLAS detector

Measurements of the yield and nuclear modification factor, RAA, for inclusive jet production are performed using 0.49 nb−1of Pb+Pb data at √sNN=5.02 TeV and 25 pb−1of ppdata at √s=5.02 TeV with the ATLAS detector at the LHC. Jets are reconstructed with the anti-kt algorithm with radius parameter R =0.4 and are measured over the transverse momentum range of 40–1000 GeV in six rapidity intervals covering |y| < 2.8. The magnitude of RAA increases with increasing jet transverse momentum, reaching a value of approximately 0.6 at 1 TeVin the most central collisions. The magnitude of RAAalso increases towards peripheral collisions. The value of RAA is independent of rapidity at low jet transverse momenta, but it is observed to decrease with increasing rapidity at high transverse moment

Search for invisible Higgs boson decays in vector boson fusion at √s = 13 TeV with the ATLAS detector

We report a search for Higgs bosons that are produced via vector boson fusion and subsequently decay into invisible particles. The experimental signature is an energetic jet pair with invariant mass of O(1) TeV and O(100) GeV missing transverse momentum. The analysis uses 36.1fb−1of ppcollision data at √s=13 TeV recorded by the ATLAS detector at the LHC. In the signal region the 2252 observed events are consistent with the background estimation. Assuming a 125 GeV scalar particle with Standard Model cross sections, the upper limit on the branching fraction of the Higgs boson decay into invisible particles is 0.37 at 95% confidence level where 0.28 was expected. This limit is interpreted in Higgs portal models to set bounds on thewimp–nucleon scattering cross section. We also consider invisible decays of additional scalar bosons with masses up to 3 TeV for which the upper limits on the cross section times branching fraction are in the range of 0.3–1.7 pb

Preferential expression of mutant ABCD1 allele is common in adrenoleukodystrophy female carriers but unrelated to clinical symptoms

<p>Abstract</p> <p>Background</p> <p>Approximately 20% of adrenoleukodystrophy (X-ALD) female carriers may develop clinical manifestations, typically consisting of progressive spastic gait, sensory deficits and bladder dysfunctions. A skewing in X Chromosome Inactivation (XCI), leading to the preferential expression of the X chromosome carrying the mutant <it>ABCD1 </it>allele, has been proposed as a mechanism influencing X-linked adrenoleukodystrophy (X-ALD) carrier phenotype, but reported data so far are conflicting.</p> <p>Methods</p> <p>To shed light into this topic we assessed the XCI pattern in peripheral blood mononuclear cells (PBMCs) of 30 X-ALD carriers. Since a frequent problem with XCI studies is the underestimation of skewing due to an incomplete sample digestion by restriction enzymes, leading to variable results, we developed a pyrosequencing assay to identify samples completely digested, on which to perform the XCI assay. Pyrosequencing was also used to quantify <it>ABCD1 </it>allele-specific expression. Moreover, very long-chain fatty acid (VLCFA) levels were determined in the same patients.</p> <p>Results</p> <p>We found severely (≥90:10) or moderately (≥75:25) skewed XCI in 23 out of 30 (77%) X-ALD carriers and proved that preferential XCI is mainly associated with the preferential expression of the mutant <it>ABCD1 </it>allele, irrespective of the manifestation of symptoms. The expression of mutant <it>ABCD1 </it>allele also correlates with plasma VLCFA concentrations.</p> <p>Conclusions</p> <p>Our results indicate that preferential XCI leads to the favored expression of the mutant <it>ABCD1 </it>allele. This emerges as a general phenomenon in X-ALD carriers not related to the presence of symptoms. Our data support the postulated growth advantage of cells with the preferential expression of the mutant <it>ABCD1 </it>allele, but argue against the use of XCI pattern, <it>ABCD1 </it>allele-specific expression pattern and VLCFA plasma concentration as biomarkers to predict the development of symptoms in X-ALD carriers.</p