Charge-conjugation violating neutrino interactions in supernovae

The well known charge conjugation violating interactions in the Standard Model increase neutrino- and decrease anti-neutrino- nucleon cross sections. This impacts neutrino transport in core collapse supernovae through "recoil" corrections of order the neutrino energy $k$ over the nucleon mass $M$. All $k/M$ corrections to neutrino transport deep inside a protoneutron star are calculated from angular integrals of the Boltzmann equation. We find these corrections significantly modify neutrino currents at high temperatures. This produces a large mu and tau number for the protoneutron star and can change the ratio of neutrons to protons. In addition, the relative size of neutrino mean free paths changes. At high temperatures, the electron anti-neutrino mean free path becomes {\it longer} than that for mu or tau neutrinos.Comment: 14 pages, 2 included ps figures, subm. to Phys. Rev.

The L-amino acid oxidase of Neurospora

In 1944 one of us described a D-amino acid oxidase in extracts of Neurospora crassa (1). Except for slight activity against L-glutamate, no oxidation of L-amino acids was observed. Recently a means for inducing the formation of a soluble L-amino acid oxidase by the mold was reported by Bender, Krebs, and Horowitz (2). This is accomplished by reducing the biotin content of the basal medium (3) from the 5 γ per liter usually employed to 0.25 γ per liter. When cultured in such a medium, Neurospora produces an active L-amino acid oxidase which can be demonstrated both in extracts and in the medium. Reduction of the biotin level produces no effect on the D-amino acid oxidase, which is still found in extracts but not in the culture medium. The activity of the L-oxidase toward thirty-eight amino acids has been investigated by Bender and Krebs (4). The initial purpose of the present investigation was to explore certain possibilities for a genetic study of the enzyme. Of special interest was the fact, cited by Bender et al. (a), that the oxidase could not be detected in all of the wild type strains tested. The question arose as to whether this is due to the genetic inability of certain strains to form the enzyme. In connection with the investigation of this problem a general survey of the properties of the enzyme was carried out, together with a preliminary study of the mechanism of the biotin effect and of the adaptive formation of the enzyme. The results of these studies are reported below. Simultaneously with our investigation and independently of it, Dr. K. Burton (5), working in Professor Krebs’ laboratory, has carried out a study of the Neurospora L-amino acid oxidase. Where our respective studies overlap mutual confirmation was obtained in most essential points. We wish to thank Dr. Burton for permission to read his manuscript before publication

The Origin of Life

The origin of life is in a sense a genetic problem, for, as H. J. Muller pointed out many years ago, the essential attribute that identifies living matter is its capacity to replicate itself and its variants (1). Because this uniquely biological property has its physical basis in proteins and nucleic acids, the goal of modern work on the origin of life is to discover the manner of origin of these polymers and of the interactions between them that constitute the genetic mechanism. In attempting to review this subject in a limited space, we cannot undertake an exhaustive treatment. Rather, we summarize work published principally since 1970 in the following areas, with emphasis on those aspects that are of greatest current interest: 1. precambrian paleontology, 2. chemical evolution of genetically important monomers, 3. prebiotic dehydration-condensation reactions, 4. organic compounds in meteorites and interstellar space, and 5. biological exploration of the planets. A large number of review articles (2-5), critical and theoretical discussions (6-8), books (9-16), and conference proceedings (17-21) dealing with the origin of have appeared in recent years. In addition, a new serial, the Journal of Molecular Evolution, publishing papers on this and related subjects, appeared in 1971; the journal Space Life Sciences has been renamed "Origins of Life," and a society, the International Society for the Study of the Origin of Life, was recently founded

Predictions for the Spatial Distribution of Gluons in the Initial Nuclear State

We make predictions for the t-differential cross section of exclusive vector meson production (EVMP) in electron-ion collisions, with the aim of comparing DGLAP evolution to CGC models. In the current picture for the high-energy nucleus, nonlinear effects need to be understood in terms of low-$x$ gluon radiation and recombination as well as how this leads to saturation. EVMP grants experimental access to the edge region of the highly-boosted nuclear wavefunction, where the saturation scale for CGC calculations becomes inaccessible to pQCD. On the other hand, DGLAP evolution requires careful consideration of unitarity effects. The existing $J/{\psi}$ photoproduction data in ep collisions provides a baseline for these theoretical calculations. Under different small-$x$ frameworks we obtain a measurable distinction in both the shape and normalization of the differential cross section predictions. These considerations are relevant for heavy ion collisions because the initial state may be further constrained, thus aiding in quantitative study of the quark-gluon plasma.Comment: 4 pages, 2 figures, 6th Hard Probes Conference 201

Semiparametric estimation of a panel data proportional hazards model with fixed effects

This paper considers a panel duration model that has a proportional hazards specification with fixed effects. The paper shows how to estimate the baseline and integrated baseline hazard functions without assuming that they belong to known, finitedimensional families of functions. Existing estimators assume that the baseline hazard function belongs to a known parametric family. Therefore, the estimators presented here are more general than existing ones. This paper also presents a method for estimating the parametric part of the proportional hazards model with dependent right censoring, under which the partial likelihood estimator is inconsistent. The paper presents some Monte Carlo evidence on the small sample performance of the new estimators

Equation of State of nuclear matter in a Virial expansion of nucleons and nuclei

We study the equation of state (EOS) of nuclear matter at subnuclear density in a Virial expansion for a nonideal gas. The gas consists of neutrons, protons, alpha particles, and 8980 species of nuclei with $A \ge 12$ and masses from the finite-range droplet model (FRDM). At very low density, the Virial expansion reduces to nuclear statistical equilibrium. At higher density, the Virial results match smoothly to the relativistic mean field results discussed in our previous paper. We tabulate the resulting EOS at over 73,000 grid points in the temperature range $T$ = 0.158 to 15.8 MeV, the density range $n_B$ = 10$^{-8}$ to 0.1 fm$^{-3}$, and the proton fraction range $Y_P$ = 0.05 to 0.56. In the future we plan to match these low density results to our earlier high density mean field results, and generate a full EOS table for use in supernova and neutron star merger simulations. This Virial EOS is exact in the low density limit.Comment: 15 pages, minor changes, Physical Review C in pres

Finite element-integral simulation of static and flight fan noise radiation from the JT15D turbofan engine

An iterative finite element integral technique is used to predict the sound field radiated from the JT15D turbofan inlet. The sound field is divided into two regions: the sound field within and near the inlet which is computed using the finite element method and the radiation field beyond the inlet which is calculated using an integral solution technique. The velocity potential formulation of the acoustic wave equation was employed in the program. For some single mode JT15D data, the theory and experiment are in good agreement for the far field radiation pattern as well as suppressor attenuation. Also, the computer program is used to simulate flight effects that cannot be performed on a ground static test stand

Nonparametric estimation of an additive quantile regression model

This paper is concerned with estimating the additive components of a nonparametric additive quantile regression model. We develop an estimator that is asymptotically normally distributed with a rate of convergence in probability of n^{-r/(2+10)} when the additive components are r-times continuously differentiable for some r\geq2. This result holds regardless of the dimension of the covariates and, therefore, the new estimator has no curse of dimensionality. In addition, the estimator has an oracle property and is easily extended to a generalized additive quantile regression model with a link function. The numerical performance and usefulness of the estimator are illustrated by Monte Carlo experiments and an empirical example

A No Black Hole Theorem

We show that one cannot put a stationary (extended) black hole inside certain gravitating flux-tubes. This includes an electric flux-tube in five-dimensional Einstein-Maxwell theory, as well as the standard flux-branes of string theory. The flux always causes the black hole to grow indefinitely. One finds a similar restriction in a Kaluza-Klein setting where the higher dimensional spacetime contains no matter.Comment: 20 pages, 4 figures. v2: reference adde

Relativistic nuclear structure effects in quasielastic neutrino scattering

Charged-current cross sections are calculated for quasielastic neutrino and antineutrino scattering using a relativistic meson-nucleon model. We examine how nuclear-structure effects, such as relativistic random-phase-approximation (RPA) corrections and momentum-dependent nucleon self-energies, influence the extraction of the axial form factor of the nucleon. RPA corrections are important only at low-momentum transfers. In contrast, the momentum dependence of the relativistic self-energies changes appreciably the value of the axial-mass parameter, $M_A$, extracted from dipole fits to the axial form factor. Using Brookhaven's experimental neutrino spectrum we estimate the sensitivity of M$_A$ to various relativistic nuclear-structure effects.Comment: 26 pages, revtex, 6 postscript figures (available upon request