Summary of pre-2008 Machine Induced Background Estimates for the LHCb Experiment

This document summarizes the pre-2008 estimates of particle flux arriving at the LHCb experiment from machine (LHC) related background sources. These particles arrive in the form of showers from both beam-gas interactions in the dispersion suppression and long straight section of IR8 and from proton losses on the IR8 tertiary collimators due to betatron cleaning inefficiencies, momentum cleaning inefficiencies and elastic beam-gas interactions along the LHC beam orbit

Mixed motivic sheaves (and weights for them) exist if 'ordinary' mixed motives do

The goal of this paper is to prove: if certain 'standard' conjectures on motives over algebraically closed fields hold, then over any 'reasonable' $S$ there exists a motivic $t$-structure for the category of Voevodsky's $S$-motives (as constructed by Cisinski and Deglise). If $S$ is 'very reasonable' (for example, of finite type over a field) then the heart of this $t$-structure (the category of mixed motivic sheaves over $S$) is endowed with a weight filtration with semi-simple factors. We also prove a certain 'motivic decomposition theorem' (assuming the conjectures mentioned) and characterize semi-simple motivic sheaves over $S$ in terms of those over its residue fields. Our main tool is the theory of weight structures. We actually prove somewhat more than the existence of a weight filtration for mixed motivic sheaves: we prove that the motivic $t$-structure is transversal to the Chow weight structure for $S$-motives (that was introduced previously and independently by D. Hebert and the author; weight structures and their transversality with t-structures were also defined by the author in recent papers). We also deduce several properties of mixed motivic sheaves from this fact. Our reasoning relies on the degeneration of Chow-weight spectral sequences for 'perverse 'etale homology' (that we prove unconditionally); this statement also yields the existence of the Chow-weight filtration for such (co)homology that is strictly restricted by ('motivic') morphisms.Comment: a few minor corrections mad

On birational involutions of P3P^3

Let $X$ be a rationally connected three-dimensional algebraic variety and let $\tau$ be an element of order two in the group of its birational selfmaps. Suppose that there exists a non-uniruled divisorial component of the $\tau$-fixed point locus. Using the equivariant minimal model program we give a rough classification of such elements.Comment: 24 pages, late

Detection of alien Pelophylax species in Sardinia (western Mediterranean, Italy)

Sardinian herpetofauna represent a valuable biodiversity resource in the Mediterranean Basin. Among amphibians, most of the taxa are indeed endemic to the island. In contrast, water frogs of the Pelophylax genus are considered allochthonous to Sardinia, and are traditionally assigned to the Italian pool frog (P. bergeri) and its hybridogenetic hybrid (P. kl. hispanicus). Members of this genus were recently found in certain sites in northern and southern Sardinia, and ascribed to the “ridibundus” group (the “Marsh frog” species complex). As the absence of clear phenotypic diagnostic features complicates the identification of distinct Pelophylax species, particularly European P. ridibundus, P. kurtmuelleri and several still undescribed “bedriagae” taxa, an informative diagnostic mitochondrial marker (ND3) was isolated in this work in order to detect the occurrence of distinct lineages in alien Sardinian populations. As water frogs are known to readily hybridize in the wild, two further diagnostic nuclear markers (SAI-1 and 4 microsatellite loci) were subsequently screened in order to exclude the occurrence of hybrid genotypes. According to our results, three distinct taxa were detected on the island, and assigned to P. kurtmuelleri (the Balkan frog), and two cryptic taxa of the “bedriagae” group. Nuclear markers only successfully amplified alleles diagnostic for the “ridibundus”-type (R) genome. Accordingly, we can exclude hybridization with the Italian pool frog already introduced on the island, although further studies are needed to better address the occurrence of new hybrid lineages stemming from the cross between the taxa detected in this work. As eggs and tadpoles have been detected in the field, alien populations can thus be considered successfully established in Sardinia. Our study revealed for the first time the occurrence of the alien Balkan frog in the western Mediterranean. It is worthy of note that this taxon shows a high invasion potential in mainland Europe. The establishment of alien Pelophylax populations in Sardinia may be favored by vacant niches. Nonetheless, the dry hot season could limit their expansion along rivers

Weights for relative motives; relation with mixed complexes of sheaves

The main goal of this paper is to define the so-called Chow weight structure for the category of Beilinson motives over any 'reasonable' base scheme $S$ (this is the version of Voevodsky's motives over $S$ defined by Cisinski and Deglise). We also study the functoriality properties of the Chow weight structure (they are very similar to the well-known functoriality of weights for mixed complexes of sheaves). As shown in a preceding paper, the Chow weight structure automatically yields an exact conservative weight complex functor (with values in $K^b(Chow(S))$). Here $Chow(S)$ is the heart of the Chow weight structure; it is 'generated' by motives of regular schemes that are projective over $S$. Besides, Grothendiek's group of $S$-motives is isomorphic to $K_0(Chow(S))$; we also define a certain 'motivic Euler characteristic' for $S$-schemes. We obtain (Chow)-weight spectral sequences and filtrations for any cohomology of motives; we discuss their relation to Beilinson's 'integral part' of motivic cohomology and to weights of mixed complexes of sheaves. For the study of the latter we introduce a new formalism of relative weight structures.Comment: a few minor corrections mad

Zero-Dimensional Model for Dynamic Behavior of Engineered Rubber in Automotive Applications

Abstract This paper presents a zero-dimensional model for the simulation of the mechanical behavior of automotive engineered rubber components, such as flexible couplings. The objective is to develop a real-time-capable model, able to simulate the behavior of a driveline containing elastomer components: the engineered rubber model has to correlate stretch to stress, the mechanical behavior being represented by means of a hysteresis cycle. The study presents the implementation of Maxwell and Voigt models, showing their limits in the representation of the material behavior: elastomers present a nonlinear response in the relationship stress-strain. A combination of Maxwell and Voigt models, with stiffness and damping variable according to the stress and strain rate, to represent nonlinear material responses, is coupled to a relaxation model, in order to represent the Mullins effect (the rubber mechanical behavior also depends on load history). Experimental tests have been carried out with different pre-load settings, stress amplitudes and stress frequencies. Tests results have been used to calibrate the parameters defining the simulation model, comparing the model outputs to experimental data: an optimization algorithm has been applied, with the aim of minimizing the results discrepancy with respect to experimental results. The optimization tool has been also used to reduce the number of parameters defining the model, in order to simplify the required computational power, avoiding at the same time over-parametrization. In the second section of the paper, the model is used for the simulation of a different rubber component, whose behavior is identified using quasi-static load ramps, frequency and amplitude sweeps, steps and random cycles. An alternative model formulation, minimizing the degrees of freedom is then applied to the new dataset. The model parameters are separately optimized using different tests, in order to capture the specific mechanical behavior. Finally, the identified parameters are used to simulate the elastomer response in random tests, comparing the results to experimental data, to evaluate the simulation quality in terms of RMSE

Studies on Model Water-in-Oil (w/o) Emulsions: Phase Behavior, Emulsion Stability, and Hydrate Formation

Colloidal dispersions are widely encountered in several industrial settings including in ink, paint, and food formulations, as well as during subsea oil production. The present study focusses on the formation of hydrates in subsea oil pipelines from colloidal precursors that cause plugging and have tremendous environmental and economic consequences. Model systems for hydrate precursors are studied – water in cyclopentane emulsions stabilized by either SPAN 80 or AOT surfactants. The phase behavior, emulsion stability, and hydrate formation mechanisms are delineated using experimental techniques such as dynamic light scattering, spectroturbidimetry, and differential scanning calorimetry. The phase behavior is found to strongly depend upon the emulsion stabilizer with AOT systems displaying strong “solubilization” in contrast to SPAN 80 systems. Furthermore, for AOT systems the emulsion stability decreases with an increase in AOT concentration from 1 wt% to 5 wt %. For SPAN 80 systems, the emulsion stability is largely unaffected by its concentration. Additionally studies are underway to study the effect of temperature on emulsion stability and to identify the mechanisms for hydrate growth. Overall, the insights obtained from the present study will help in designing strategies for hydrate plug prevention, thereby, facilitating safe and economic oil production

Advances in spinal muscular atrophy therapeutics

Spinal muscular atrophy (SMA) is a progressive, recessively inherited neuromuscular disease, characterized by the degeneration of lower motor neurons in the spinal cord and brainstem, which leads to weakness and muscle atrophy. SMA currently represents the most common genetic cause of infant death. SMA is caused by the lack of survival motor neuron (SMN) protein due to mutations, which are often deletions, in theSMN1gene. In the absence of treatments able to modify the disease course, a considerable burden falls on patients and their families. Greater knowledge of the molecular basis of SMA pathogenesis has fuelled the development of potential therapeutic approaches, which are illustrated here. Nusinersen, a modified antisense oligonucleotide that modulates the splicing of theSMN2mRNA transcript, is the first approved drug for all types of SMA. Moreover, the first gene therapy clinical trial using adeno-associated virus (AAV) vectors encoding SMN reported positive results in survival and motor milestones achievement. In addition, other strategies are in the pipeline, including modulation ofSMN2transcripts, neuroprotection, and targeting an increasing number of other peripheral targets, including the skeletal muscle. Based on this premise, it is reasonable to expect that therapeutic approaches aimed at treating SMA will soon be changed, and improved, in a meaningful way. We discuss the challenges with regard to the development of novel treatments for patients with SMA, and depict the current and future scenarios as the field enters into a new era of promising effective treatments