Probing lepton flavour (universality) violation at NA62 and future kaon experiments

Recent results from the LHC's first run have revealed intriguing departures from lepton flavour universality in the semi-leptonic decays of $B$-mesons. We discuss the complementary role that rare kaon decays can provide in testing new physics explanations of these flavour anomalies. In the framework of minimal flavour violation, we relate the chiral low-energy constants involved in $K\to\pi\ell\ell'$ and $K\to\ell\ell'$ (\ell = \mu \mbox{ or } e) with the new physics Wilson coefficients of the $b\to s$ effective Hamiltonian. We comment on the determination of these low-energy constants at NA62 and future kaon experiments, as well as the required improvements in sensitivity necessary to test the $B$-physics anomalies in the kaon sector.Comment: 6 pages, Presented at the International Conference on Kaon Physics 2016, 14-17 September 2016, Birmingham, U

When alarm bells ring: emergency tinnitus

OBJECTIVE: The aim of this study is to develop a diagnostic-therapeutic algorithm for those suffering from tinnitus who seek emergency aid. MATERIALS AND METHODS: A literature review has been performed on articles from the last 30 years. RESULTS: It is important to activate medical or surgical diagnostic and therapeutic strategies, in order to safeguard and rehabilitate the various functions affected. Psychiatric comorbidity is the most frequent pathological condition of those with serious or catastrophic tinnitus. In these cases, mortality risk is linked to suicide, morbidity to tinnitus-correlated distress. CONCLUSIONS: Tinnitus, mainly linked to loss of hearing, is a frequent symptom among the population at large. About 7% of those affected by tinnitus turn to their doctor to solve their problem, while between 0.5 and 2% request urgent medical assistance. Their cry for help may be the result of an acute onset of tinnitus or the rapid impairment of an already chronic condition. Tinnitus is not considered an urgent ear, nose and throat (ENT) condition by the Associazione Otorinolaringologi Ospedalieri Italiani (AOOI) [Italian Association of Hospital ENT], even though there are many pathological conditions, sometimes serious, associated with tinnitus and emergency action is necessary to reduce the risk of morbidity and mortality

Determinants of World Demand for U.S. Corn Seeds: The Role of Trade Costs

The United States is a large net exporter of corn seeds. Seed trade, including that of corn, has been expanding, but its determinants are not well understood. This paper econometrically investigates the determinants of world demand for U.S. corn seeds with a detailed analysis of trade costs impeding export flows to various markets, including costs associated with distance, tariffs, and sanitary and phytosanitary (SPS) regulations. The analysis relies on a gravity-like model based on an explicit specification of derived demand for seed by foreign corn producers, estimated based on data from 48 countries and for the years 1989 to 2004. An SPS count variable is incorporated as a shifter in the unit cost of seeds faced by foreign users. A sample selection framework is used to account for the determination of which trade flows are positive. All trade costs matter and have had a negative impact on U.S. corn seed exports. Tariffs matter most, followed by distance and SPS measures. �

A decentralized scalable approach to voltage control of DC islanded microgrids

We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed by several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates to a reference value the voltage of the Point of Common Coupling (PCC) of the corresponding DGU. Notably, off-line control design is conducted in a Plug-and-Play (PnP) fashion meaning that (i) the possibility of adding/removing a DGU without spoiling stability of the overall ImG is checked through an optimization problem; (ii) when a DGU is plugged in or out at most neighbouring DGUs have to update their controllers and (iii) the synthesis of a local controller uses only information on the corresponding DGU and lines connected to it. This guarantee total scalability of control synthesis as the ImG size grows or DGU gets replaced. Yes, under mild approximations of line dynamics, we formally guarantee stability of the overall closed-loop ImG. The performance of the proposed controllers is analyzed simulating different scenarios in PSCAD.Comment: arXiv admin note: text overlap with arXiv:1405.242

Plug-and-play and coordinated control for bus-connected AC islanded microgrids

This paper presents a distributed control architecture for voltage and frequency stabilization in AC islanded microgrids. In the primary control layer, each generation unit is equipped with a local controller acting on the corresponding voltage-source converter. Following the plug-and-play design approach previously proposed by some of the authors, whenever the addition/removal of a distributed generation unit is required, feasibility of the operation is automatically checked by designing local controllers through convex optimization. The update of the voltage-control layer, when units plug -in/-out, is therefore automatized and stability of the microgrid is always preserved. Moreover, local control design is based only on the knowledge of parameters of power lines and it does not require to store a global microgrid model. In this work, we focus on bus-connected microgrid topologies and enhance the primary plug-and-play layer with local virtual impedance loops and secondary coordinated controllers ensuring bus voltage tracking and reactive power sharing. In particular, the secondary control architecture is distributed, hence mirroring the modularity of the primary control layer. We validate primary and secondary controllers by performing experiments with balanced, unbalanced and nonlinear loads, on a setup composed of three bus-connected distributed generation units. Most importantly, the stability of the microgrid after the addition/removal of distributed generation units is assessed. Overall, the experimental results show the feasibility of the proposed modular control design framework, where generation units can be added/removed on the fly, thus enabling the deployment of virtual power plants that can be resized over time

Yeast Irc6p is a novel type of conserved clathrin coat accessory factor related to small G proteins.

Clathrin coat accessory proteins play key roles in transport mediated by clathrin-coated vesicles. Yeast Irc6p and the related mammalian p34 are putative clathrin accessory proteins that interact with clathrin adaptor complexes. We present evidence that Irc6p functions in clathrin-mediated traffic between the trans-Golgi network and endosomes, linking clathrin adaptor complex AP-1 and the Rab GTPase Ypt31p. The crystal structure of the Irc6p N-terminal domain revealed a G-protein fold most related to small G proteins of the Rab and Arf families. However, Irc6p lacks G-protein signature motifs and high-affinity GTP binding. Also, mutant Irc6p lacking candidate GTP-binding residues retained function. Mammalian p34 rescued growth defects in irc6 cells, indicating functional conservation, and modeling predicted a similar N-terminal fold in p34. Irc6p and p34 also contain functionally conserved C-terminal regions. Irc6p/p34-related proteins with the same two-part architecture are encoded in genomes of species as diverse as plants and humans. Together these results define Irc6p/p34 as a novel type of conserved clathrin accessory protein and founding members of a new G protein-like family

The effect of temperature anisotropy on observations of Doppler dimming and pumping in the inner corona

Recent observations of the spectral line profiles and intensity ratio of the O VI 1032 {\AA} and 1037.6 {\AA} doublet by the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO), made in coronal holes below 3.5 $R_s$, provide evidence for Doppler dimming of the O VI 1037.6 {\AA} line and pumping by the chromospheric C II 1037.0182 {\AA} line. Evidence for a significant kinetic temperature anisotropy of O$^{5+}$ ions was also derived from these observations. We show in this Letter how the component of the kinetic temperature in the direction perpendicular to the magnetic field, for both isotropic and anisotropic temperature distributions, affects both the amount of Doppler dimming and pumping. Taking this component into account, we further show that the observation that the O VI doublet intensity ratio is less than unity can be accounted for only if pumping by C II 1036.3367 {\AA} in addition to C II 1037.0182 {\AA} is in effect. The inclusion of the C II 1036.3367 {\AA} pumping implies that the speed of the O$^{5+}$ ions can reach 400 km/s around 3 $R_s$ which is significantly higher than the reported UVCS values for atomic hydrogen in polar coronal holes. These results imply that oxygen ions flow much faster than protons at that heliocentric distance.Comment: 9 pages, 3 figure

Time-dependent Nonlinear Optical Susceptibility of an Out-of-Equilibrium Soft Material

We investigate the time-dependent nonlinear optical absorption of a clay dispersion (Laponite) in organic dye (Rhodamine B) water solution displaying liquid-arrested state transition. Specifically, we determine the characteristic time $\tau_D$ of the nonlinear susceptibility build-up due as to the Soret effect. By comparing $\tau_D$ with the relaxation time provided by standard dynamic light scattering measurements we report on the decoupling of the two collective diffusion times at the two very different length scales during the aging of the out-of-equilibrium system. With this demonstration experiment we also show the potentiality of nonlinear optics measurements in the study of the late stage of arrest in soft materials