Ab initio calculation of the electromagnetic and neutral-weak response functions of 4He and 12C

Precise measurement of neutrino oscillations, and hence the determination of their masses demands a quantitative understanding of neutrino-nucleus interactions. To this aim, two-body meson-exchange currents have to be accounted for along within realistic models of nuclear dynamics. We summarize our progresses towards the construction of a consistent framework, based on quantum Monte Carlo methods and on the spectral function approach, that can be exploited to accurately describe neutrino interactions with atomic nuclei over the broad kinematical region covered by neutrino experiments.Comment: 8 pages, 4 figure, Proceedings of the 21st International Conference on Few-Body Problems in Physics, Chicago, Illinois, US

Response to. comment on optic nerve sheath diameter ultrasound evaluation in intensive care unit: possible role and clinical aspects in neurological critical patients' daily monitoring

Comment on "Optic Nerve Sheath Diameter Ultrasound Evaluation in Intensive Care Unit: Possible Role and Clinical Aspects in Neurological Critical Patients' Daily Monitoring"

Linear Toric Fibrations

These notes are based on three lectures given at the 2013 CIME/CIRM summer school. The purpose of this series of lectures is to introduce the notion of a toric fibration and to give its geometrical and combinatorial characterizations. Polarized toric varieties which are birationally equivalent to projective toric bundles are associated to a class of polytopes called Cayley polytopes. Their geometry and combinatorics have a fruitful interplay leading to fundamental insight in both directions. These notes will illustrate geometrical phenomena, in algebraic geometry and neighboring fields, which are characterized by a Cayley structure. Examples are projective duality of toric varieties and polyhedral adjunction theory

Intermolecular Potentials of Argon, Methane, and Ethane

The viscosities of argon, methane, and ethane are reported over a temperature range from ∼210°K to ∼475°K. In conjunction with second virial coefficient data, the viscosities have been employed to estimate the potential parameters for an Exp:6 potential. For the spherically symmetric molecules a single set of parameters served to reproduce the equilibrium and transport properties with serviceable accuracy. For ethane the procedure failed, and this failure was taken as further evidence for the fundamental inadequacy of the assumptions of central forces and elastic collisions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70109/2/JCPSA6-28-6-1152-1.pd

Life Support: Long Term Storage of Solid Waste in an Enclosed Membrane System

In deep space missions, maintaining life support is of the utmost priority. In such a closed system, human waste must be stored and treated. Simulated feces (ersatz) will be inoculated with microbes representing normal fecal flora, mixed with urine brine and shredded refuse of products typically used in space missions. Composting methods often use alternating layers of waste with scraps of carboniferous materials (finely shredded refuse). By preparing membrane bags with a homogenized ersatz and carboniferous refuse mixture and membrane bags with alternating layers of ersatz and carboniferous refuse, it may be possible to monitor anaerobic thermophillic digestion of the waste if internal temperatures of 45-55°C are reached (these temperatures can kill pathogenic microbes). Monitoring the temperature, pH, and osmolarity of membrane bags filled with this waste over a period of approximately 4 weeks can give valuable data to considering the plausibility of a compost-like procedure to sanitize and store human waste over a long period of time

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitationin turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon(R) samples in different situations and we show the limitations of the method.Comment: 8 pages, 7 figure

Spreads of PG(3,q)PG(3,q) and ovoids of polar spaces

To any spread S of PG(3,q) corresponds a family of locally hermitian ovoids of the Hermitian surface H(3, q^2), and conversely; if in addition S is a semifield spread, then each associated ovoid is a translation ovoid, and conversely. In this paper we calculate the translation group of the locally hermitian ovoids of H(3,q^2) arising from a given semifield spread, and we characterize the p-semiclassical ovoid constructed by Cossidente, Ebert, Marino and Siciliano as the only translation ovoid of H(3,q^2) whose translation group is abelian. If S is a spread of PG(3,q) and O(S) is one of the associated ovoids of H(3,q^2), then using the duality between H(3,q^2) and Q^-(5, q) , another spread of PG(3,q) , say S_1, can be constructed. On the other hand, using the Barlotti-Cofman representation of H(3,q^2), one more spread of a 3-dimensional projective space, say S_2, arises from the ovoid O(S). Lunardon has posed some questions on the relations among S, S_1 and S_2; here we prove that the three spreads are always isomorphic

On the line shift and oscillator strength of Xe II lines in the spectra of HnMn stars

Aims. The ultimate goal that has motivated this work is to achieve realistic oscillator strength (gf) values to find reliable values of stellar abundances. We aim to compare the gf valúes of Xe ii lines found with different theoretical and experimental methods. Methods. We have undertaken calculations using the quasirelativistic and relativistic Hartree-Fock methods. Then we compare these results with those previously obtained from UVES spectra of HgMn stars. Results. 1) Our theoretical gf values are more realistic than those previously obtained for most lines. When we consider only unblended, isolated, relatively noise-free lines, however, our theoretical gf values and Yuce's stellar values differ little from each other. 2) In a discussion of the origin of the previously observed discrepancy between the wavelengths of Xe ii lines deducted from stellar spectra and those published by National Institute of Standards and Technology (NIST), we conclude that stellar wavelengths could be considered the standard wavelengths whenever the densities in stellar atmospheres are smaller than 1 × 1016 part. cm-3.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Asignación iónica de líneas del Xe IV

The Xe IV spectrum between 2280 and 6100 A emitted by a new model of a non conventional spectroscopic «ource, has been studied. Si* hundred and «ixty «even lines has been assigned to this ion by employing the conventional method of energy variation, and the characteristic form of the spectral lines resulting from this type of spectral lamp has been particularly considered.El espectro del Xe IV entre 2280 y 6100 A emitido por un nuevo modelo de fuente espectroscópica no-convencional, ha sido estudiado. Seiscientas sesenta y siete líneas han sido asignadas a este ion, empleando el método convencional de variación de energía, y ha sido particularmente considerada la forma característica de las líneas espectrales que resultan de este tipo de fuente espectral.Facultad de Ingenierí

Neutrino-nucleus cross section within the extended factorization scheme

The factorization scheme, based on the impulse approximation and the spectral function formalism, has been recently generalized to allow the description of electromagnetic nuclear interactions driven by two-nucleon currents. We have extended this framework to the case of weakly charged and neutral currents, and carried out calculations of the double-differential neutrino-carbon and neutrino-oxygen cross sections using two different models of the target spectral functions. The results, showing a moderate dependence on the input spectral function, confirm that our approach provides a consistent treatment of all reaction mechanisms contributing to the signals detected by accelerator-based neutrino experiments