Origin of the heavy elements in HD 140283 Measurement of europium abundance

Context. HD 140283 is a nearby (V = 7.7) subgiant metal-poor star, extensively analysed in the literature. Although many spectra have been obtained for this star, none showed a signal-to-noise (S/N) ratio high enough to enable a very accurate derivation of abundances from weak lines. Aims. The detection of europium proves that the neutron-capture elements in this star originate in the r-process, and not in the s-process, as recently claimed in the literature. Methods. Based on the OSMARCS 1D LTE atmospheric model and with a consistent approach based on the spectrum synthesis code Turbospectrum, we measured the europium lines at 4129 angstrom and 4205 angstrom, taking into account the hyperfine structure of the transitions. The spectrum, obtained with a long exposure time of seven hours at the Canada-France-Hawaii Telescope (CFHT), has a resolving power of 81 000 and a S/N ratio of 800 at 4100 angstrom. Results. We were able to determine the abundance A(Eu) = -2.35 +/- 0.07 dex, compatible with the value predicted for the europium from the r-process. The abundance ratio [Eu/Ba] = +0.58 +/- 0.15 dex agrees with the trend observed in metal-poor stars and is also compatible with a strong r-process contribution to the origin of the neutron-capture elements in HD 140283.

Complete fusion enhancement and suppression of weakly bound nuclei at near barrier energies

We consider the influence of breakup channels on the complete fusion of weakly bound systems in terms of dynamic polarization potentials. It is argued that the enhancement of the cross section at sub-barrier energies may be consistent with recent experimental observations that nucleon transfer, often leading to breakup, is dominant compared to direct breakup. The main trends of the experimental complete fusion cross sections are analyzed in the framework of the DPP approach. The qualitative conclusions are supported by CDCC calculations including a sequential breakup channel, the one neutron stripping of Li-7 followed by the breakup of Li-6.

Dependence of Generation-Recombination Noise With Gate Voltage in FD SOI MOSFETs

A model for computing the generation-recombination noise due to traps within the semiconductor film of fully depleted silicon-on-insulator MOSFET transistors is presented. Dependence of the corner frequency of the Lorentzian spectra on the gate voltage is addressed in this paper, which is different to the constant behavior expected for bulk transistors. The shift in the corner frequency makes the characterization process easier. It helps to identify the energy position, capture cross sections, and densities of the traps. This characterization task is carried out considering noise measurements of two different candidate structures for single-transistor dynamic random access memory devices.

Does H -> gamma gamma taste like vanilla new physics?

We analyse the interplay between the Higgs to diphoton rate and electroweak precision measurements constraints in extensions of the Standard Model with new uncolored charged fermions that do not mix with the ordinary ones. We also compute the pair production cross sections for the lightest fermion and compare them with current bounds.

Positron collisions with ethene

We present experimental and theoretical cross sections for positron collisions with ethene molecules. The experimental total cross sections (TCSs) were obtained with a linear transmission technique, for energies from 0.1 eV up to 70 eV. The calculations employed the Schwinger multichannel method and were performed in the static plus polarization approximation for energies up to 10 eV. Our calculated elastic cross sections indicate a Ramsauer-Townsend minimum around 2.8 eV and a virtual state, in agreement with previous calculations by da Silva et al. [Phys. Rev. Lett. 77, 1028 (1996)]. We found reasonable agreement between the calculated elastic integral cross section and the measured total cross section below the positronium formation threshold. The present results are also in quite good agreement with available theoretical and experimental data, although for the experiments this is only true for TCSs above about 7 eV.

New measurement of the B-11(p,alpha(0))Be-8 bare-nucleus S(E) factor via the Trojan horse method

A new measurement of the B-11(p,alpha(0))Be-8 has been performed applying the Trojan horse method (THM) to the H-2(B-11,alpha Be-8(0))n quasi-free reaction induced at a laboratory energy of 27 MeV. The astrophysical S(E) factor has been extracted from similar to 600 keV down to zero energy by means of an improved data analysis technique and it has been compared with direct data available in the literature. The range investigated here overlaps with the energy region of the light element LiBeB stellar burning and with that of future aneutronic fusion power plants using the B-11+p fuel cycle. The new investigation described here confirms the preliminary results obtained in the recent TH works. The origin of the discrepancy between the direct estimate of the B-11(p,alpha(0))Be-8 S(E)-factor at zero energy and that from a previous THM investigation is quantitatively corroborated. The results obtained here support, within the experimental uncertainties, the low-energy S(E)-factor extrapolation and the value of the electron screening potential deduced from direct measurements.

Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at root s(NN)=2.76 TeV

In this Letter we report the first results on pi(+/-), K-+/-, p, and (p) over bar production at midrapidity (vertical bar y vertical bar < 0.5) in central Pb-Pb collisions at root s(NN) = 2.76 TeV, measured by the ALICE experiment at the LHC. The p(T) distributions and yields are compared to previous results at root s(NN) = 200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with root s(NN), which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/pi ratio is in line with predictions from the thermal model, the p/pi ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.

Identification of a Tooth-Like Foreign Body in Swine Sausage

A tooth-like foreign body (FB) was found inside a sausage bread. Analysis aimed to investigate whether the FB was a tooth and its origin. The FB was measured, weighed, photographed, and radiographed. Macroscopic findings were suggestive of an anterior tooth. Histological slides of undecalcified cross-sections of the FB and samples of human and swine teeth were prepared. Histological features of the FB (in light microscopy, 125X magnification) were discrepant from human tissues. Compared histological analysis displayed majority of features consistent with a hypsodont swine tooth, probably a canine. Cellularized cementum in crown region, adjacent to the enamel, and shape of the cementocytes were the main criteria excluding the possibility of human origin of the FB. Scanning electronic microscopy and energy-dispersive spectroscopy were not performed because of fewer features to be analyzed and FB size. It was concluded that the FB may have been incorporated during meat grinding of the sausage.

D-S(+) meson production at central rapidity in proton-proton collisions at root s=7 TeV

The P-T-differential inclusive production cross section of the prompt charm-strange meson D-s(+) in the rapidity range vertical bar y vertical bar < 0.5 was measured in proton-proton collisions at root s = 7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98 x 10(8) events collected with a minimum-bias trigger. The corresponding integrated luminosity is L-int = 4.8 nb(-1). Reconstructing the decay D-s(+) -> phi pi(+) with phi -> K-K+, and its charge conjugate, about 480 D-s(+/-) mesons were counted, after selection cuts, in the transverse momentum range 2 < P-T < 12 GeV/c. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D-0, D+, D*+ and D-s(+)) were determined both as a function of p(T) and integrated over p(T)after extrapolating to full p(T) range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e(+)e(-), ep and pp interactions at various centre-of-mass energies. (C) 2012 CERN. Published by Elsevier By. All rights reserved.

Alveolar Bone Morphology in Patients With Bilateral Complete Cleft Lip and Palate in the Mixed Dentition: Cone Beam Computed Tomography Evaluation

Objectives: To verify the thickness and level of alveolar bone around the teeth adjacent to the cleft by means of cone beam computed tomography (CBCT) in patients with complete bilateral cleft lip and palate prior to bone graft surgery and orthodontic intervention. Method: The sample comprised 10 patients with complete bilateral cleft lip and palate (five boys and five girls) in the mixed dentition. The mean age was 9.5 years, and all subjects showed a G3 interarch relationship according to the Bauru index. The thickness of alveolar bone surrounding the maxillary incisors and the maxillary canines was measured in CBCT axial section using the software iCAT Xoran System. The distance between the alveolar bone crest and the cement-enamel junction (CEJ) was measured in cross sections. Results: The tomography images showed a thin alveolar bone plate around teeth adjacent to clefts. No bone dehiscence was observed in teeth adjacent to clefts during the mixed dentition. A slight increase in the distance between the alveolar bone crest and the CEJ was observed in the mesial and lingual aspects of canines adjacent to cleft. Conclusion: In patients with BCLP in the mixed dentition, teeth adjacent to the alveolar cleft are covered by a thin alveolar bone plate. However, the level of alveolar bone crest around these teeth seems to be normal, and no bone dehiscence was identified at this age.

CP asymmetries in the supersymmetric trilepton signal at the LHC

In the CP-violating Minimal Supersymmetric Standard Model, we study the production of a neutralino-chargino pair at the LHC. For their decays into three leptons, we analyze CP asymmetries which are sensitive to the CP phases of the neutralino and chargino sector. We present analytical formulas for the entire production and decay process, and identify the CP-violating contributions in the spin correlation terms. This allows us to define the optimal CP asymmetries. We present a detailed numerical analysis of the cross sections, branching ratios, and the CP observables. For light neutralinos, charginos, and squarks, the asymmetries can reach several 10%. We estimate the discovery potential for the LHC to observe CP violation in the trilepton channel.

New structures in the continuum of C-15 populated by two-neutron transfer

The C-13(O-18,O-16)C-15 reaction has been studied at 84 MeV incident energy. The ejectiles have been detected at forward angles and C-15 excitation energy spectra have been obtained up to about 20 MeV. Several known bound and resonant states of C-15 have been identified together with two unknown structures at 10.5 MeV (FWHM = 2.5 MeV) and 13.6 MeV (FWHM = 2.5 MeV). Calculations based Oil the removal of two uncorrelated neutrons from the projectile describe a significant part of the continuum observed in the energy spectra. In particular the structure at 10.5 MeV is dominated by a resonance of C-15 near the C-13 + n + n threshold. Similar structures are found in nearby nuclei such as C-14 and Be-11. (c) 2012 Elsevier BM. All rights reserved.

Light vector meson production in pp collisions at root s=7 TeV ALICE Collaboration

The ALICE experiment has measured low-mass dimuon production in pp collisions at root s = 7 TeV in the dimuon rapidity region 2.5 < y < 4. The observed dimuon mass spectrum is described as a superposition of resonance decays (eta, rho, omega, eta', phi) into muons and semi-leptonic decays of charmed mesons. The measured production cross sections for omega and phi are sigma(omega)(1 < p(t) < 5 GeV/c. 2.5 < y < 4) = 5.28 +/- 0.54(stat) +/- 0.49(syst) mb and sigma(phi)(1 < p(t) < 5 GeV/c. 2.5 < y < 4) = 0.940 +/- 0.084(stat) +/- 0.076(syst) mb. The differential cross sections d(2)sigma/dy dp(t) are extracted as a function of p(t) for omega and phi. The ratio between the rho and omega cross section is obtained. Results for the phi are compared with other measurements at the same energy and with predictions by models. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.

Influence of nanoparticle size on the nonlinear optical properties of magnetite ferrofluids

The nonlinear index of refraction (n(2)) and the two-photon absorption coefficient (beta) of water-based ferrofluids made of magnetite nanocrystals of different sizes and with different coatings have been measured through the Z-scan technique, with ultrashort (femtoseconds) laser pulses. Their third-order susceptibility is calculated from the values of n(2) and beta. The influence of different particles' coatings and sizes on these nonlinear optical properties are investigated. The values of n(2) and beta depend more significantly on the nanoparticles' size than on the particular coating. We observe a decrease of beta as the nanoparticles' diameters decrease, although the optical gap is found to be the same for all samples. The results are interpreted considering modifications in the electronic orbital shape due to the particles' nanosize effect.

Electron collisions with the HCOOH...(H2O)n (n=1, 2 and 3) complexes in liquid phase: the influence on the π* shape resonance of formic acid

In this conference we report cross sections for elastic collisions of low-energy electrons with the HCOOH…(H2O)n complexes, with n = 1, 2 and 3. The scattering cross sections were computed with the Schwinger multichannel method [K. Takatsuka and V. McKoy, Phys. Rev. A 24 , 2473 (1981); Phys. Rev. A 30 , 1734 (1984)] with pseudopotentials [M. H. F. Bettega, L. G. Ferreira, and M. A. P. Lima, Phys. Rev. A 47, 1111 (1993)] in the static-exchange and static-exchange plus polarization approximations, for energies from 0.5 eV to 6 eV. We considered some diÆerent hydrogen-bonded structures for the complexes that were generated with classical Monte Carlo simulations [K. Coutinho and S. Canuto, J. Chem. Phys. 113, 9132, (2000)]. The aim of this work is to investigate the effect of the surrounding water molecules on the π* shape resonance of the solute. Previous theoretical and experimental studies carried out in the gas phase reported a π* state for HCOOH at around 1.9 eV. For the n = 1 case and for all complexes, the stabilization of the resonance was observed (it appears at lower energy compared to the value obtained in the gas phase), as reported previously for the CH2O…H2O complexes [T. C. Freitas, M. A. P. Lima, S. Canuto, and M. H. F. Bettega, Phys. Rev. A 80, 062710 (2009)]. This result indicates that the presence of the solvent may affect the processes related to the π* state, such as the molecular dissociation by electron impact. For the n = 2 case we have observed both stabilization and destabilization of the π* resonance, that is associated with the hydrogen bond donor or acceptor role of the water molecules in the complexes. For the n = 3 case, preliminary static-exchange results show the stabilization of the π* state. We propose an explanation of the stabilization/destabilization of the π* state in terms of the polarization of the solute due to the surrounding water molecules and the net charge in the solute.