A theoretical analysis of Ballistic Electron Emission Microscopy: k-space distributions and spectroscopy

We analyze BEEM experiments. At low temperatures and low voltages, near the threshold value of the Schottky barrier, the BEEM current is dominated by the elastic component. Elastic scattering by the lattice results in the formation of focused beams and narrow lines in real space. To obtain the current injected in the semiconductor, we compute the current distribution in reciprocal space and, assuming energy and $k_{\parallel}$ conservation. Our results show an important focalization of the injected electron beam and explain the similarity between BEEM currents for Au/Si(111) and Au/Si(100).Comment: 17 pages, 5 figures (postscript), Latex, APS, http://www.icmm.csic.es/Pandres/pedro.htm. Appl. Surf. Sci. (in press

Finite Temperature Pion Scattering to one-loop in Chiral Perturbation Theory

We present the pion-pion elastic scattering amplitude at finite temperature to one-loop in Chiral Perturbation Theory. The thermal scattering amplitude properly defined allows to generalize the perturbative unitarity relation to the $T\neq 0$ case. Our result provides a model independent prediction of an enhanced pion-pion low-energy phase shift with the temperature and it has physical applications within the context of Relativistic Heavy Ion Collisions.Comment: 11 pages, 2 figures. Some references and clarifying comments added and new figures included. Final version to appear in Physics Letters

Radiative corrections to low energy neutrino reactions

We show that the radiative corrections to charged current (CC) nuclear reactions with an electron(positron) in the final state are described by a universal function. The consistency of our treatment of the radiative corrections with the procedure used to extract the value of the axial coupling constant $g_A$ is discussed. To illustrate we apply our results to (anti)neutrino deuterium disintegration and to $pp$ fusion in the sun. The limit of vanishing electron mass is considered, and a simple formula valid for E_{obs}\gsim 1 MeV is obtained. The size of the nuclear structure-dependent effects is also discussed. Finally, we consider CC transitions with an electron(positron) in the initial state and discuss some applications to electron capture reactions.Comment: 23 pages, 5 figure

Identification and Functional Characterization of Two Intronic NIPBL Mutations in Two Patients with Cornelia de Lange Syndrome

Cornelia de Lange syndrome (CdLS) is a rare genetically heterogeneous disorder with a high phenotypic variability including mental retardation, developmental delay, and limb malformations. The genetic causes in about 30% of patients with CdLS are still unknown. We report on the functional characterization of two intronic NIPBL mutations in two patients with CdLS that do not affect a conserved splice-donor or acceptor site. Interestingly, mRNA analyses showed aberrantly spliced transcripts missing exon 28 or 37, suggesting the loss of the branch site by the c.5329-15A>G transition and a disruption of the polypyrimidine by the c.6344del(-13)-(-8) deletion. While the loss of exon 28 retains the reading frame of the NIBPL transcript resulting in a shortened protein, the loss of exon 37 shifts the reading frame with the consequence of a premature stop of translation. Subsequent quantitative PCR analysis demonstrated a 30% decrease of the total NIPBL mRNA levels associated with the frameshift transcript. Consistent with our results, this patient shows a more severe phenotype compared to the patient with the aberrant transcript that retains its reading frame. Thus, intronic variants identified by sequencing analysis in CdLS diagnostics should carefully be examined before excluding them as nonrelevant to disease

High rate of autonomic neuropathy in Cornelia de Lange Syndrome

Background: Cornelia de Lange Syndrome (CdLS) is a rare congenital disorder characterized by typical facial features, growth failure, limb abnormalities, and gastroesophageal dysfunction that may be caused by mutations in several genes that disrupt gene regulation early in development. Symptoms in individuals with CdLS suggest that the peripheral nervous system (PNS) is involved, yet there is little direct evidence. Method: Somatic nervous system was evaluated by conventional motor and sensory nerve conduction studies and autonomic nervous system by heart rate variability, sympathetic skin response and sudomotor testing. CdLS Clinical Score and genetic studies were also obtained. Results: Sympathetic skin response and sudomotor test were pathological in 35% and 34% of the individuals with CdLS, respectively. Nevertheless, normal values in large fiber nerve function studies. Conclusions: Autonomic nervous system (ANS) dysfunction is found in many individuals with Cornelia de Lange Syndrome, and could be related to premature aging

Sustained safety and performance of the second-generation drug-eluting absorbable metal scaffold in patients with de novo coronary lesions: 12-month clinical results and angiographic findings of the BIOSOLVE-II first-in-man trial.

Metal absorbable scaffolds constitute a conceptually attractive alternative to polymeric scaffolds. Promising 6-month outcomes of a second-generation drug-eluting absorbable metal scaffold (DREAMS 2G), consisting of an absorbable magnesium scaffold backbone, have been reported. We assessed the 12-month safety and performance of this novel device. The prospective, international, multi-centre, first-in-man BIOSOLVE-II trial enrolled 123 patients with up to two de novo lesions with a reference diameter between 2.2 and 3.7 mm. All patients were scheduled for angiographic follow-up at 6 months, and-if subjects consented-at 12 months. Dual antiplatelet therapy was recommended for 6 months. Quantitative coronary angiography (QCA) parameters remained stable from 6 to 12 months [paired data of 42 patients: in-segment late lumen loss 0.20 ± 0.21 mm vs. 0.25 ± 0.22 mm, P = 0.117, Δ 0.05 ± 0.21 mm (95% CI: -0.01;0.12); in-scaffold late lumen loss 0.37 ± 0.25 mm vs. 0.39 ± 0.27 mm, P = 0.446, Δ 0.03 ± 0.22 (95% CI: -0.04;0.10), respectively]. Intravascular ultrasound and optical coherence tomography findings corroborated the QCA results. Target lesion failure occurred in four patients (3.4%), consisting of one death of unknown cause, one target-vessel myocardial infarction, and two clinically driven target lesion revascularization. No additional event occurred beyond the 6-month follow-up. During the entire follow-up of 12 months, none of the patients experienced a definite or probable scaffold thrombosis. The novel drug-eluting metal absorbable scaffold DREAMS 2G showed a continuous favourable safety profile up to 12 months and stable angiographic parameters between 6 and 12 months. NCT01960504

Stochastic Production Of Kink-Antikink Pairs In The Presence Of An Oscillating Background

We numerically investigate the production of kink-antikink pairs in a $(1+1)$ dimensional $\phi^4$ field theory subject to white noise and periodic driving. The twin effects of noise and periodic driving acting in conjunction lead to considerable enhancement in the kink density compared to the thermal equilibrium value, for low dissipation coefficients and for a specific range of frequencies of the oscillating background. The dependence of the kink-density on the temperature of the heat bath, the amplitude of the oscillating background and value of the dissipation coefficient is also investigated. An interesting feature of our result is that kink-antikink production occurs even though the system always remains in the broken symmetry phase.Comment: Revtex, 21 pages including 7 figures; more references adde

Three body systems with strangeness and exotic systems

We report on four $\Sigma$'s and three $\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances found by solving the Faddeev equations in the coupled channel approach, which can be associated to the existing $S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. On the other hand we also report on a new, hidden strangeness $N^*$ state, mostly made of $K \bar{K} N$, with mass around 1920 MeV, which we think could be responsible for the peak seen in the $\gamma p \to K^+ \Lambda$ around this energy. Finally we address a very novel topic in which we show how few body systems of several $\rho$ mesons can be produced, with their spins aligned up to J=6, and how these states found theoretically can be associated to several known mesons with spins J=2,3,4,5,6.Comment: Talk at the 21st European Conference on Few Body Problems in Physics, Salamanca, Sep. 201

Vector meson production and nucleon resonance analysis in a coupled-channel approach for energies m_N < sqrt(s) < 2 GeV I: pion-induced results and hadronic parameters

We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states gamma N, pi N, 2 pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass up to sqrt(s) = 2 GeV. In this analysis we find strong evidence for the resonances P_{31}(1750), P_{13}(1900), P_{33}(1920), and D_{13}(1950). The omega N production mechanism is dominated by large P_{11}(1710) and P_{13}(1900) contributions. In this first part, we present the results of the pion-induced reactions and the extracted resonance and background properties with emphasis on the difference between global and purely hadronic fits.Comment: 54 pages, 26 figures, discussion extended, typos corrected, references updated, to appear in Phys. Rev.

MAU2 and NIPBL variants impair the heterodimerization of the cohesin loader subunits and cause Cornelia de Lange syndrome

The NIPBL/MAU2 heterodimer loads cohesin onto chromatin. Mutations inNIPBLaccount for most cases ofthe rare developmental disorder Cornelia de Lange syndrome (CdLS). Here we report aMAU2 variant causing CdLS, a deletion of seven amino acids that impairs the interaction between MAU2 and the NIPBL N terminus.Investigating this interaction, we discovered that MAU2 and the NIPBL N terminus are largely dispensable fornormal cohesin and NIPBL function in cells with a NIPBL early truncating mutation. Despite a predicted fataloutcome of an out-of-frame single nucleotide duplication inNIPBL, engineered in two different cell lines,alternative translation initiation yields a form of NIPBL missing N-terminal residues. This form cannot interactwith MAU2, but binds DNA and mediates cohesin loading. Altogether, our work reveals that cohesin loading can occur independently of functional NIPBL/MAU2 complexes and highlights a novel mechanism protectiveagainst out-of-frame mutations that is potentially relevant for other genetic conditions