Lepton-pair Cerenkov radiation emitted by tachyonic neutrinos: Lorentz-covariant approach and IceCube data

Current experiments do not exclude the possibility that one or more neutrinos are very slightly superluminal or that they have a very small tachyonic mass. Important bounds on the size of a hypothetical tachyonic neutrino mass term are set by lepton pair Cerenkov radiation (LPCR), i.e., by the decay channel nu -> e^+ e^- nu which proceeds via a virtual Z0 boson. Here, we use a Lorentz-invariant dispersion relation which leads to very tight constraints on the tachyonic mass of neutrinos; we also calculate decay and energy loss rates. A possible cutoff seen in the IceCube neutrino spectrum for E_nu > 2 PeV, due to the potential onset of LPCR, is discussed.Comment: 7 pages; accepted for publication in the Advances of High-Energy Physic

\u27Horae\u27 in Roman Funerary Inscriptions

References to hours on Roman tombstones, long assumed to be a means of displaying affection for children, are shown to be the basis for horoscopes of the afterlife. Statistical analysis argues for the accuracy of the figures of hours recorded. Close study of the inscriptions demonstrates that all references, whether to points in time or durations are records of times of death. Such inscriptions were set up from the first-sixth centuries CE and were most prevalent in Rome, Italy, and North Africa. Among both pagans and Christians these times allow for the casting of horoscopes of the afterlife. The individual hours would have been associated with signs of the Zodiac, gods of the Pantheon, or the Apostles. The hours recorded also indicate the tutelar who would watch over the deceased in the afterlife. This practice develops in the late Republic as Rome encounters Hellenistic ideas of astrology and time measurement

Novel Method of Measuring Electron Positron Colliding Beam Parameters

Through the simultaneous measurement of the transverse size as a function of longitudinal position, and the longitudinal distribution of luminosity, we are able to measure the $\beta_y^\ast$ (vertical envelope function at the collision point), vertical emittance, and bunch length of colliding beams at the Cornell Electron-positron Storage Ring (CESR). This measurement is possible due to the significant ``hourglass'' effect at CESR and the excellent tracking resolution of the CLEO detector.Comment: 11 pages, 4 figures, submitted to NIM

A water test facility for liquid rocket engine turbopump cavitation testing

Improved understanding of the physics of turbopump cavitation and its relation to engine design parameters is needed to enhance propulsion system reliability and reduce development costs. A program to investigate cavitation phenomena in liquid rocket turbopumps has been initiated at The Aerospace Corporation to improve capability to predict the phenomena. This paper presents the methodology for the design of a new water-flow cavitation test facility capable of testing a variety of rocket turbopumps over a wide range of operating conditions to simulate the thermal characteristics of cryogenic propellants. This new cavitation test facility is now operational and qualification testing is in progress. Future experiments conducted in the facility will provide valuable data for the characterization of turbopump cavitation phenomena as well as evaluation, development, and validation of cavitation models.http://deepblue.lib.umich.edu/bitstream/2027.42/84280/1/CAV2009-final11.pd

Genotypic and Phenotypic Characterization of a Neutralization-Resistant Breakthrough Population of HIV-1

AbstractCertain antibody neutralization escape mutants of HIV-1 map outside of the antibody recognition epitope, thereby suggesting the presence of nonlinear conformational domains. In an effort to begin to define the interacting regions of the HIV envelope proteins, a neutralization-sensitive clone of HIV-1, HXB2/BH10Sal-Bam, was passaged in the presence of the V3-specific monoclonal antibody 0.5β. DNA sequence analysis of the V3 domain of the breakthrough viral populations revealed one population that retained the parental V3 genotype. Quantitative DNA sequence analysis of this breakthrough population revealed the presence of mutational “hotspots” in several envelope domains that are noncontiguous with V3. Mutations were seen throughout gp41 and the C1, V1/V2, C2, and C5 domains of gp120. In contrast, other regions of gp120, C3, V4, C4, and V5 remained totally unchanged. Within V1, three residues within a 14-amino acid stretch experienced five substitutions and in C5 three residues within a 7-amino acid stretch experienced four substitutions. This finding, that certain residues clustered within particular domains (V1/V2, C5, and gp41) experienced multiple substitutions under a defined environmental stressor, suggests that the degree of adaptive plasticity exhibited by the HIV envelope is limited. Based on this observation it may be possible, using a set of antibodies to various envelope epitopes, to discern a set of rules which explain the interactions of the various envelope domains with each other and with their environment. The insight gained into the physiologic constraints that the envelope proteins are subject to may be useful in developing therapeutic and vaccination strategies

Volume Comparison for Hypersurfaces in Lorentzian Manifolds and Singularity Theorems

We develop area and volume comparison theorems for the evolution of spacelike, acausal, causally complete hypersurfaces in Lorentzian manifolds, where one has a lower bound on the Ricci tensor along timelike curves, and an upper bound on the mean curvature of the hypersurface. Using these results, we give a new proof of Hawking's singularity theorem.Comment: 15 pages, LaTe

The MAHB, the Culture Gap, and Some Really Inconvenient Truths

Humanity's failure to take adequate actions to stem a likely environmental collapse calls for extraordinary measures to understand and alter human behavior, argues Paul Ehrlich. His Millennium Assessment of Human Behavior (MAHB) aims to chart the path to a sustainable future