3,390 research outputs found
Fermion masses in noncommutative geometry
Recent indications of neutrino oscillations raise the question of the
possibility of incorporating massive neutrinos in the formulation of the
Standard Model (SM) within noncommutative geometry (NCG). We find that the NCG
requirement of Poincare duality constrains the numbers of massless quarks and
neutrinos to be unequal unless new fermions are introduced. Possible scenarios
in which this constraint is satisfied are discussed.Comment: 4 pages, REVTeX; typos are corrected in (19), "Possible Solutions"
and "Conclusion" are modified; additional calculational details are included;
references are update
K-Shell Auger Spectrum Of Atomic Oxygen
We have observed the K-shell Auger spectrum in atomic oxygen. A total of ten transitions originating from the decay of the 4P and 2P states of the O+(1s-1) ion are identified and assigned to final states of the O2+ ion. Relative intensities for each of these transitions are obtained, allowing the extraction of the dependence of the Auger decay on the multiplet structure in both the initial and final states of this basic open-shell atom
A Study of Naturally Occurring Algicides Produced by Freshwater Algae
The mode of action of the algicide produced by Pandorina morum was examined by exposing Volvox globator and isolates spinach chloroplasts to a partially purified algicide preparation. Oxygen evolution of Volvox, whole chloroplasts and broken chloroplasts (minus the Calvin cycle),was reduced indicating that the algicide inhibits the light reactions of photosynthesis. Oxygen evolution studies of other Volvocaceae confirmed the observation that Pandorina morum is not significantly influenced by its own inhibitor. Molecular weight approximation by gel filtration established that the inhibitor has a low molecular weight (probably below 100 mw). Field studies indicate that this algicide has tremendous potential as a control for the growth of nuisance algal growth
Analogy, Dirac-Majorana Neutrino Duality and the Neutrino Oscillations
The intent of this paper is to convey a new primary physical idea of a
Dirac-Majorana neutrino duality in relation to the topical problem of neutrino
oscillations. In view of the new atmospheric, solar and the LSND neutrino
oscillation data, the Pontecorvo oscillation analogy is generalized
to the notion of neutrino duality with substantially different physical meaning
ascribed to the long-baseline and the short-baseline neutrino oscillations. At
the level of CP-invariance, the suggestion of dual neutrino properties defines
the symmetric two-mixing-angle form of the widely discussed four-neutrino
-mixing scheme, as a result of the lepton charge conservation selection
rule and a minimum of two Dirac neutrino fields. With neutrino duality, the
two-doublet structure of the Majorana neutrino mass spectrum is a vestige of
the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is
natural because it is produced by a lepton charge symmetry violating
perturbation on a zero-approximation system of two twofold mass-degenerate
Dirac neutrino-antineutrino pairs. A set of inferences related to the neutrino
oscillation phenomenology in vacuum is considered.Comment: 13 pages, LaTeX. Minor modifications, new references adde
1968 Costs for Field Work
Four methods of figuring your field work are included in this article. One is a guide of costs taken from actual costs on the university farms, which reflects some of the recent increases
Tele-operated high speed anthropomorphic dextrous hands with object shape and texture identification
This paper reports on the development of two number of robotic hands have been developed which focus on tele-operated high speed anthropomorphic dextrous robotic hands. The aim of developing these hands was to achieve a system that seamlessly interfaced between humans and robots. To provide sensory feedback, to a remote operator tactile sensors were developed to be mounted on the robotic hands. Two systems were developed, the first, being a skin sensor capable of shape reconstruction placed on the palm of the hand to feed back the shape of objects grasped and the second is a highly sensitive tactile array for surface texture identification
Structure and dynamics of the 4p -\u3e ns,md autoionizing resonances between the P-3 and S-1 thresholds in atomic bromine
The relative partial photoionization cross sections sigma(i) and photoelectron angular distribution parameters beta(1) are measured for all possible final ionic states of Br+ between the P-3(2) and S-1(0) thresholds. The decay patterns of the autoionizing 4p(4 3)P(1,0) nl, 4p(4 1)D(2) nl, and 4p(4 1)S(0) nl Rydberg series arising from the 4p ins,md excitations are observed at the fine-structure level in all available channels. For each Rydberg series, the energies, quantum defects, and photoelectron angular distribution parameters are determined, as well as the widths and shape parameters of the low-lying members. Relative total cross sections are derived from the partial cross sections and from ion-yield measurements over the lowest members of the P-3(1,0) and D-1(2) series. All major spectroscopic and dynamic properties of these series are reported for this open-shell atom. Conclusions are drawn from the comprehensive data sets in comparison with other halogen atoms and the neighboring closed-shell rare gas atoms. Our results, encompassing the entire autoionization regime, are compared with other experimental data and theoretical calculations, where available
Signal recognition efficiencies of artificial neural-network pulse-shape discrimination in HPGe -decay searches
A pulse-shape discrimination method based on artificial neural networks was
applied to pulses simulated for different background, signal and signal-like
interactions inside a germanium detector. The simulated pulses were used to
investigate variations of efficiencies as a function of used training set. It
is verified that neural networks are well-suited to identify background pulses
in true-coaxial high-purity germanium detectors. The systematic uncertainty on
the signal recognition efficiency derived using signal-like evaluation samples
from calibration measurements is estimated to be 5\%. This uncertainty is due
to differences between signal and calibration samples
- …