Brans-Dicke geometry

We reveal the non-metric geometry underlying omega-->0 Brans-Dicke theory by unifying the metric and scalar field into a single geometric structure. Taking this structure seriously as the geometry to which matter universally couples, we show that the theory is fully consistent with solar system tests. This is in striking constrast with the standard metric coupling, which grossly violates post-Newtonian experimental constraints.Comment: 8 pages, v2 with additional comment and reference

Constraining Axion Dark Matter with Big Bang Nucleosynthesis

We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD $\theta$ angle that redshifts in the early universe, increasing the neutron-proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of 4He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for time-varying neutron EDMs. The QCD axion does not couple strongly enough to affect BBN.Comment: 5 pages, 2 figures; v2 typos corrected, numerical values for quark masses update

Orbital magnetization and Chern number in a supercell framework: Single k-point formula

The key formula for computing the orbital magnetization of a crystalline system has been recently found [D. Ceresoli, T. Thonhauser, D. Vanderbilt, R. Resta, Phys. Rev. B {\bf 74}, 024408 (2006)]: it is given in terms of a Brillouin-zone integral, which is discretized on a reciprocal-space mesh for numerical implementation. We find here the single ${\bf k}$-point limit, useful for large enough supercells, and particularly in the framework of Car-Parrinello simulations for noncrystalline systems. We validate our formula on the test case of a crystalline system, where the supercell is chosen as a large multiple of the elementary cell. We also show that--somewhat counterintuitively--even the Chern number (in 2d) can be evaluated using a single Hamiltonian diagonalization.Comment: 4 pages, 3 figures; appendix adde

Selfish Dark Matter

We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at $B$-factories or future beam dump experiments.Comment: 18+5 pages, 2 figures; Journal version: Added references, small changes to the free-streaming length estimate

The application of flow cytometry in microbiological monitoring during winemaking: two case studies

In this work, we exploit a general flow cytometry technique involved in the differentiation of live and dead yeast cells for two applications in winemaking. The discrimination of yeast populations is achieved using two fluorescent dyes that measure the metabolic activity and membrane integrity of the yeast. This analytical approach is first applied for quality control of active dry yeast. Results are discussed in comparison with the Codex Oenologique International (International Oenological Codex) of the International Organisation of Vine and Wine (OIV), demonstrating that analysis using flow cytometry is a valuable alternative, given the ease of execution and the high quality of results obtained in terms of reproducibility, repeatability, and confidence interval. In the second case, we apply flow cytometry as a technique for monitoring the production of sparkling wines using the "Champenoise" method, and describe the evolution of yeast through the production process. In this case, results are directly compared with those obtained with the two methods (plate counts and direct microscopic count) listed in the OIV standards, in order to ensure a thorough understanding of the improvements related to the use of flow cytometry

Proof-of-principle of surface detection with air-guided quantum cascade lasers

We report a proof-of-principle of surface detection with air-guided quantum cascade lasers. Laser ridges were designed to exhibit an evanescent electromagnetic field on their top surface that can interact with material or liquids deposited on the device. We employ photoresist and common solvents to provide a demonstration of the sensor setup. We observed spectral as well as threshold currents changes as a function of the deposited material absorption curve. A simple model, supplemented by 2D numerical finite element method simulations, allows one to explain and correctly predict the experimental results

Shutdown of turbulent convection as a new criterion for the onset of spring phytoplankton blooms

The onset of phytoplankton blooms in late winter, early spring has been traditionally associated with the shoaling of the mixed layer above a critical depth. Here we show that the onset of a bloom can also be triggered by a reduction in air–sea fluxes at the end of winter. When net cooling subsides at the end of winter, turbulent mixing becomes weak, thereby increasing the residence time of phytoplankton cells in the euphotic layer and allowing a bloom to develop. The necessary change in the air–sea flux generally precedes mixed-layer shoaling, and may provide a better indicator for the onset of the spring bloom than the mixed-layer depth alone. Our hypothesis is supported by numerical simulations and remote sensing data.United States. Office of Naval Research (Award N00014-08-1-1060

Geometry for the accelerating universe

The Lorentzian spacetime metric is replaced by an area metric which naturally emerges as a generalized geometry in quantum string and gauge theory. Employing the area metric curvature scalar, the gravitational Einstein-Hilbert action is re-interpreted as dynamics for an area metric. Without the need for dark energy or fine-tuning, area metric cosmology explains the observed small acceleration of the late Universe.Comment: 4 pages, 1 figur

Endovascular repair for acute traumatic transection of the descending thoracic aorta: experience of a single centre with a 12-years follow up

Background: Most blunt aortic injuries occur in the proximal proximal descending aorta causing acute transection of this vessel. Generally, surgical repair of the ruptured segment of aorta is associated with high rates of morbidity and mortality and in this view endovascular treatment seems to be a valid and safer alternative. Aim of this article is to review our experience with endovascular approach for the treatment of acute traumatic rupture of descending thoracic aorta. Methods: From April 2002 to November 2014, 11 patients (9 males and 2 females) were referred to our Department with a diagnosis of acute transection of thoracic aorta. Following preoperative Computed Tomography (CT) evaluation, thoracic endovascular aortic repair (TEVAR) with left subclavian artery coverage was performed. Follow-up consisted clinical and instrumental (CT, Duplex ultrasound) controls at discharge, 1, 3 and 6 months and yearly thereafter. Results: At 12-year follow up, the overall survival for the entire patients cohort was 100 %, no major or minor neurological complications and no episode of left arm claudication occurred. Cardiovascular, respiratory and bleeding complications, in the early period, was represented by minor, non fatal events. No stent graft failure, collapse, leak or distal migration were detected at CT scan during the entire follow up period. Conclusions: According to our experience, despite the small number of patient population, TEVAR procedure with with left subclavian artery coverage, performed in emergency settings, seems to provide excellent long term results. Trials registration: The protocol was registered at a public trials registry, www.clinicaltrials.gov (trial identifier NCT02376998)