Axion detection through resonant photon-photon collisions

We investigate the prospect of an alternative laboratory-based search for the coupling of axions and axionlike particles to photons. Here, the collision of two laser beams resonantly produces axions, and a signal photon is detected after magnetic reconversion, as in light-shining-through-walls (LSW) experiments. Conventional searches, such as LSW or anomalous birefringence measurements, are most sensitive to axion masses for which substantial coherence can be achieved; this is usually well below optical energies. We find that using currently available high-power laser facilities, the bounds that can be achieved by our approach outperform traditional LSW at axion masses between 0.5–6 eV, set by the optical laser frequencies and collision angle. These bounds can be further improved through coherent scattering off laser substructures, probing axion-photon couplings down to gaγγ ∼ 10−8 GeV−1, comparable with existing CAST bounds. Assuming a day long measurement per angular step, the QCD axion band can be reached

Rapid decline of fasting glucose in HCV diabetic patients treated with direct-acting antiviral agents

Association between HCV infection and diabetes has been widely postulated. Little is known about the impact of direct acting antiviral agents (DAAs) on glycemic control. Aim of our study was to evaluate the glycemic control modifications in a case series of HCV+ diabetic population receiving DAAs. We retrospectively evaluated 149 HCV+ patients in two different institutions affiliated to the Sapienza University: Policlinico Umberto I of Rome and Ospedale Santa Maria Goretti of Latina. We were able to identify 29 patients with T2DM (19% of total population) who were receiving different IFN-free regimens. During-treatment fasting glucose values were available for 21 patients and analysis showed a statistically significant reduction (p=0,007), the reduction mean value was -52,86 mg/dl. An A1C value during treatment (week 4 or week 8 or week 12) was available for 10 patients and the analysis showed a statistically significant reduction (p=0,021) with a reduction mean value of -1,95%. 6 patients (23%) needed to reduce hypoglycemic drugs, 8 of 10 patients showed reduction of A1C, 14 of 21 patients (67%) showed reduced FG during treatment. FG and A1C reductions values were independent from which DAA was present in the regimen, HCV genotype, BMI and HIV status. In order to avoid hypoglycemic events, diabetic patients undergoing DAAs should be closely monitorized for reduction of hypoglycemic drugs. Furthermore, diabetes could be considered, in our opinion, as an element to prioritize treatment in those patients with no apparent liver disease

The flexibility of virtual energy storage based on the thermal inertia of buildings in renewable energy communities: A techno-economic analysis and comparison with the electric battery solution

The Renewable Energy Community (REC) concept has been introduced into the European decarbonization guidelines to promote the utilization of Renewable Energy Sources (RES) and to incentivize their self-consumption at the local level. This paper analyzes the flexible use of Heat Pumps (HP) for building heating in an REC context. The Power-to-Heat (P2H) energy conversion process of HP allows the flexibility of the thermal sector to be exploited within the electricity sector: in this way, it is possible to store energy in the form of heat inside the building mass and then use the stored energy to reduce the building heating demand in the hours following the accumulation of energy. This energy storage solution has been defined as building-based Virtual Energy Storage (VES). The flexibility enabled by VES has been used to optimize the self-consumption of an REC. The flexible VES solution was evaluated, from a technical and economic point of view, through a sensitivity analysis on the variation of the RES penetration, and the results were compared with those based on a more traditional centralized electric battery (EB) storage system. The results demonstrated that the VES solution is less flexible than electric batteries. Nevertheless, both flexible solutions (VES and EB) can significantly increase the REC self-consumption: the self-consumed energy increased by between 6% and 44% thanks to the exploitation of the VES flexibility, while the EB flexibility enabled an increase in the self-consumed energy of 19% to 63% according to the scenario analyzed. However, due to the high investment cost of EB, the VES configuration resulted to be the best solution from an economic point of view

Nouvelle découverte d'empreintes laissées par des dinosaures dans la formation des couches rouges (bassin de Cuzco-Sicuani, Sud du Pérou) : conséquences stratigraphiques et tectoniques

La découverte d'empreintes laissées par le dinosaures vers le sommet de la formation des Couches Rouges permet de préciser la stratigraphie du Sud du Pérou. La durée de la sédimentation continentale du bassin de Cuzco-Sicuani n'excéderait pas 20 Ma (santonien - paléocène) et non plus 45 Ma, comme cela était jusqu'à présent admis. Le bassin d'avant-pays de Cuzco-Sicuani est caractérisé par une déformation synsédimentaire essentiellement compressive pendant toute la durée de la sédimentation des "Couches Rouges". En conséquence, une durée équivalente à celle de cette sédimentation peut être retenue pour ces événements tectoniques qui marquent ici le début de la surrection de la chaîne andine. La phase péruvienne, traditionnellement placée vers 85 Ma, représenterait ainsi le début de ces événements tectoniques. (Résumé d'auteur

Life cycle assessment of a renewable energy system with hydrogen-battery storage for a remote off-grid community

Remote areas usually do not have access to electricity from the national grid. The energy demand is often covered by diesel generators, resulting in high operating costs and significant environmental impacts. With reference to the case study of Ginostra (a village on a small island in the south of Italy), this paper analyses the environmental sustainability of an innovative solution based on Renewable Energy Sources (RES) integrated with a hybrid hydrogen-battery energy storage system. A comparative Life Cycle Assessment (LCA) has been carried out to evaluate if and to what extent the RES-based system could bring environmental improvements compared to the current diesel-based configuration. The results show that the impact of the RES-based system is less than 10% of that of the current diesel-based solution for almost all impact categories (climate change, ozone depletion, photochemical ozone formation, acidification, marine and terrestrial eutrophication and fossil resource use). The renewable solution has slightly higher values only for the following indicators: use of mineral and metal resources, water use and freshwater eutrophication. The climate change category accounts for 0.197 kg CO2 eq./kWh in the renewable scenario and 1.73 kg CO2 eq./kWh in the diesel-based scenario, which corresponds to a reduction in GHG emissions of 89%. By shifting to the RES-based solution, about 6570 t of CO2 equivalent can be saved in 25 years (lifetime of the plant). In conclusion, the hydrogen-battery system could provide a sustainable and reliable alternative for power supply in remote areas

The beginning of senior career in team sport is affected by relative age effect

Many previous studies in national team sports did not report evidence about relative age effect (RAE) in senior categories. This study aimed for the first time to determine if the RAE may specifically affect the early, but not the late, phase of senior career in elite team sports. A total of 3,319 birthdates (basketball: n = 642; rugby: n = 572; soccer: n = 1318; volleyball: n = 337; water polo: n = 450) of elite senior players were analyzed. Senior players with an age lower or equal to the 25 percentile of age were considered as early phase players while the others as late phase players. Separate Poisson regression models were applied to investigate the RAE in each sport (overall, and for early phase and late phase subgroups). Considering the overall sample, players born close to the beginning of the year were 1.57, 1.34, 2.69, 1.48, and 1.45 times more likely to reach first and second Italian division of basketball, rugby, soccer, volleyball, and water polo respectively, than those born in the last part of the year. RAE was present in all early phase subgroups. Differently, in the late phase subgroups the RAE was present only in soccer. Data highlighted a bias in the selection of senior teams, which may limit the chance to identify talented players born late in the second part of the year. Italian sport federations should promote the talent development of relatively younger players by equally promoting the joining of young players to senior teams

Light-shining-through-wall axion detection experiments with a stimulating laser

The collision of two real photons can result in the emission of axions. We investigate the performance of a modified light-shining-through-wall (LSW) axion search aiming to overcome the large signal suppression for axion masses ma≥1 eV. We propose to utilize a third beam to stimulate the reconversion of axions into a measurable signal. We thereby find that with currently available high-power laser facilities we expect bounds at axion masses between 0.5-6 eV reaching gaγγ≥10-7 GeV-1. Combining the use of optical lasers with currently operating x-ray free electron lasers, we extend the mass range to 10-100 eV

Computational Fluid Dynamic Investigation of Local Flow-Field Conditions in Lab Polymer Electrolyte Membrane Fuel Cells to Identify Degradation Stressors and Performance Enhancers

The use of polymer electrolyte membrane (PEM) fuel cells as an alternative to internal combustion engines can significantly contribute to the decarbonization of the transport sector, especially for heavy-duty applications. However, degradation is still an issue for this type of component, affecting their durability and performance. In this scenario, a detailed analysis of the anodic and cathodic distributors’ flow-field geometry may help to identify some local stressors that trigger the degradation mechanism, such as local hot spots and reactants not having a uniform distribution. A computational fluid dynamic (CFD) methodology is able to provide a volumetric description of a PEM fuel cell so it can be a useful tool to better understand the physical phenomena that govern the component operations. In this work, the open-source simulation library openFuelCell2 is adopted for a detailed analysis of two different PEM fuel cells characterized by standard distributor geometries, namely a parallel channel geometry and a serpentine configuration. The library, based on the OpenFOAM code, has been extended with a novel implementation accounting for the catalytic activity reduction due to the platinum oxide (PtOx) formation occurring under certain particular conditions. The adopted methodology is firstly validated resorting to experimental data acquired for the two different fuel cell configurations. The analysis highlights that the PtOx formation leads to a reduction in the fuel cell performance reaching up to 60–80% when operating at high voltages. Then, the effect of the distributor geometries on the component performance is investigated by resorting to in-plane and through-plane physical quantity distribution, such as reactant concentration, pressure or velocity fields. While the parallel flow channel configuration shows some diffusion losses under the rib, the serpentine channel geometry configuration can achieve some local performance peaks thanks to the convective flow in the gas diffusion layer (GDL) driven by local pressure gradients. Furthermore, the local enhancement in terms of higher current density under the rib is associated with an effective heat removal due to the high thermal capacity of the bipolar plate, avoiding the generation of local hot spots