663 research outputs found
Unknowns after the SNO Charged-Current Measurement
We perform a model-independent analysis of solar neutrino flux rates
including the recent charged-current measurement at the Sudbury Neutrino
Observatory (SNO). We derive a universal sum rule involving SNO and
SuperKamiokande rates, and show that the SNO neutral-current measurement can
not fix the fraction of solar oscillating to sterile neutrinos. The
large uncertainty in the SSM B flux impedes a determination of the sterile
neutrino fraction.Comment: Version to appear in PRL; includes analysis with anticipated SNO NC
measuremen
A p-Adic Model of DNA Sequence and Genetic Code
Using basic properties of p-adic numbers, we consider a simple new approach
to describe main aspects of DNA sequence and genetic code. Central role in our
investigation plays an ultrametric p-adic information space which basic
elements are nucleotides, codons and genes. We show that a 5-adic model is
appropriate for DNA sequence. This 5-adic model, combined with 2-adic distance,
is also suitable for genetic code and for a more advanced employment in
genomics. We find that genetic code degeneracy is related to the p-adic
distance between codons.Comment: 13 pages, 2 table
Schizophrenic active neutrinos and exotic sterile neutrinos
We implement a schizophrenic scenario for the active neutrinos in a model in
which there are also exotic right-handed neutrinos making a model with a local
U(1)_(B-L) anomaly free. Two of right-handed neutrinos carry B-L=-4 while the
third one carries B-L=5.Comment: I, A. C. B. Machado, apologize for having submitted the wrong file
before. This is in fact the version to be published in Physics Letters B 698
(2011) pp. 128-13
Bridging The Gaps: How Students Seek Disciplinary Coherence In Introductory Physics For Life Science
Students in one discipline often receive their scientific training from faculty in other disciplines. As a result of tacit disciplinary differences, especially as implemented in courses at the introductory college level, such students can have difficulty in understanding the nature of the knowledge they are learning in a discipline that they do not identify as their own. We developed a course in introductory physics for life science (IPLS) students that attempts to help them cross disciplinary boundaries. By analyzing student reasoning during recitation sections and interviews, we identified three broad ways in which students in our course meaningfully crossed boundaries: (i) by unpacking biochemical heuristics in terms of underlying physical interactions, (ii) by locating both biochemical and physical concepts within a mathematical bridging expression, and (iii) by coordinating functional and mechanistic explanations for the same biological phenomenon. Drawing on episodes from case-study interviews and in-class problem-solving sessions, we illustrate how each of these types of boundary crossing involves the coordination of students’ conceptual and epistemological resources from physics, chemistry, and biology in distinct but complementary ways. Together, these boundary crossing categories form a theoretical framework for classifying student coherence seeking. We explore how the IPLS course helps our life science students fill in the gaps that exist between traditional introductory courses, by finding and exploring questions that might otherwise fall through disciplinary cracks. By identifying these types of explanatory coherence, we hope to suggest ways of inviting life science students to participate in physics and see physics as a tool for making sense of the living world
Search for a Lorentz invariance violation in atmospheric neutrino oscillations using MACRO data
The energy spectrum of neutrino-induced upward-going muons in MACRO was
analysed in terms of special relativity principles violating effects, keeping
standard mass-induced atmospheric neutrino oscillations as the dominant source
of nu_mu nu_tau transitions. The data disfavour these exotic possibilities
even at a sub-dominant level, and stringent 90% C.L. limits are placed on the
Lorentz invariance violation parameters. These limits can also be
re-interpreted as upper bounds on the parameters describing violation of the
Equivalence Principle.Comment: 8 pages, 5 EPS figures, uses article.sty. Invited talk at C2CR 2005,
From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 September 200
Symmetric Textures in SO(10) and LMA Solution for Solar Neutrinos
We analyze a model based on SUSY SO(10) combined with SU(2) family symmetry
and symmetric mass matrices constructed by the authors recently. Previously,
only the parameter space for the LOW and vacuum oscillation (VO) solutions was
investigated. We indicate in this note the parameter space which leads to large
mixing angle (LMA) solution to the solar neutrino problem with a slightly
modified effective neutrino mass matrix. The symmetric mass textures arising
from the left-right symmetry breaking and the SU(2) symmetry breaking give rise
to very good predictions for the quark and lepton masses and mixing angles. The
prediction of our model for the |U_{e\nu_{3}}| element in the
Maki-Nakagawa-Sakata (MNS) matrix is close to the sensitivity of current
experiments; thus the validity of our model can be tested in the near future.
We also investigate the correlation between the |U_{e\nu_{3}}| element and
\tan^{2}\theta_{\odot} in a general two-zero neutrino mass texture.Comment: RevTeX4; 9 pages; 1 figur
New interactions: past and future experiments
In this talk I will review the present status and future perspectives of some
popular extensions of the conventional three-neutrino oscillation scenario,
from a purely phenomenological point of view. For concreteness I will focus
only on three specific scenarios: non-standard neutrino interactions with
matters, models with extra sterile neutrinos, and neutrino decay and
decoherence.Comment: LaTeX file using jpconf class, 8 pages, 2 tables. Proceedings of the
"XXIII International Conference on Neutrino Physics and Astrophysics"
(Neutrino 08), Christchurch, New Zealand, May 25-31, 200
The energetic efficiency of growing lambs fed highconcentrate diets with different roughages.
Abstract presented at ADSA-PSA-AMPA-ASAS Joint Annual Meeting, July, 2012, Phoenix, Arizona
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