193 research outputs found
Charge Symmetry Violating Contributions to Neutrino Reactions
The NuTeV group has measured charged and neutral current reactions for
neutrinos on iron targets. Ratios of these cross sections provide an
independent measurement of the Weinberg angle. The NuTeV value for sin^2
theta_W is three standard deviations larger than the value measured in other
electroweak processes. By reviewing theoretical estimates of parton charge
symmetry violation (CSV), we study CSV contributions to the NuTeV measurement.
We conclude that charge symmetry violating effects should remove roughly 30% of
the discrepancy between the NuTeV result and other determinations of sin^2
theta_W.Comment: 15 pages, 2 figures; Fig 2 replaced [CSV distribution calculated at
low Q^2, evolved to 20 GeV^2]; table II change
Charge Symmetry Violation Corrections to Determination of the Weinberg Angle in Neutrino Reactions
We show that the correction to the Paschos-Wolfenstein relation associated
with charge symmetry violation in the valence quark distributions is
essentially model independent. It is proportional to a ratio of quark momenta
that is independent of Q^2. This result provides a natural explanation of the
surprisingly good agreement found between our earlier estimates within several
different models. When applied to the recent NuTeV measurement, this effect
significantly reduces the discrepancy with other determinations of the Weinberg
angle.Comment: 7 pages, no figures; expanded discussion of N.ne.Z correction
Potential loss of nutrients from different rearing strategies for fattening pigs on pasture
Nutrient load and distribution on pasture were investigated with fattening pigs that: 1) spend a proportion of or their entire life on pasture, 2) were fed either restrictively or ad libitum, and 3) were weaned at different times of the year. The N and P retention in pigs decreased the longer they were kept on pasture. The contents of soil inorganic N and exchangeable K were significantly raised compared to the soil outside the enclosures but with no differences between treatments. Pig grazing did not affect extractable soil P. Regular moving of huts, feeding and water troughs was effective in ensuring that nutrients were more evenly distributed on the paddocks. Grass cover, as determined by spectral reflectance, was not related to the experimental treatments but only to time of year. During spring and summer, grass was present in parts of the paddocks, whereas during autumn and winter the pigs kept grass cover below 10%. Fattening pigs on pasture carries a high risk of nutrient loss and it is concluded that the most environmentally acceptable way of keeping fattening pigs on pasture involves a combination of reduced dietary N intake, reduced stocking rate and seasonal rather than all year production
The Iowa Homemaker vol.21, no.4
Gaucho Costume Inspires Original Design, page 2
Response to Canned Food Survey, Mr. Elmo Roper, page 3
Egg Industries and Defense, Dorothy Conquest, page 4
Test Tube Research, Lila Williamson, page 5
Iowa Staters at Stouffer’s, page 6
Food and Nutrition Highlights, page 7
Sally Plans Winter Wardrobe, Janice Wiegman, page 8
What’s New in Home Economics, Dorothy Olson, page 10
Across Alumnae Desks, Marjorie Thomas, page 12
Gourmets Ride the Airways, Marjorie Beneke, page 15
Behind Bright Jackets, Julie Wendel, page 16
Try Variety in Turkey, Mary Roberts, page 18
Journalistic Spindles, Miriam Clure, page 19
Alums in the News, Mary Sather Matthews, page 2
Validity of Flavor Symmetry and Charge Symmetry for Parton Distributions
Recent experimental measurements of the Gottfried Sum Rule, and pp and pD
Drell-Yan processes, suggest significant violation of flavor symmetry in the
proton sea. This interpretation rests on the assumption of parton charge
symmetry. Our model calculations suggest charge symmetry violation [CSV] for
parton valence distributions of a few percent. Precision measurements of
structure functions in muon and neutrino experiments allow us to set rather
stringent experimental limits on CSV in certain kinematic regions. In another
region, these experiments suggest substantial CSV effects. We suggest
experiments which could test parton CSV.Comment: 8 pages, 4 figures, talk at Workshop on Future Directions in
Quark-Nuclear Physics, Center for the Subatomic Structure of Matter,
Adelaide, Australia, Mar 9-20, 1998, to appear in conference proceeding
Kaon-Nucleus Drell-Yan Processes and Kaon Structure Functions
We investigate the information which could be obtained from Drell-Yan
processes with sufficiently intense beams of charged kaons on isoscalar
targets. It is found that combinations of and Drell-Yan
measurements on isoscalar nuclear targets would allow one to extract the kaon
sea quark distributions. These cross sections are also sensitive to the strange
valence quark distribution in the kaon, although one would need a significant
increase over the presently available kaon fluxes in order to extract this
quantity with sufficient accuracy.Comment: 9 pages plus 4 figures, on eps
Recommended from our members
NSAIDs Modulate Clonal Evolution in Barrett's Esophagus
Cancer is considered an outcome of decades-long clonal evolution fueled by acquisition of somatic genomic abnormalities (SGAs). Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce cancer risk, including risk of progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA). However, the cancer chemopreventive mechanisms of NSAIDs are not fully understood. We hypothesized that NSAIDs modulate clonal evolution by reducing SGA acquisition rate. We evaluated thirteen individuals with BE. Eleven had not used NSAIDs for 6.2±3.5 (mean±standard deviation) years and then began using NSAIDs for 5.6±2.7 years, whereas two had used NSAIDs for 3.3±1.4 years and then discontinued use for 7.9±0.7 years. 161 BE biopsies, collected at 5–8 time points over 6.4–19 years, were analyzed using 1Million-SNP arrays to detect SGAs. Even in the earliest biopsies there were many SGAs (284±246 in 10/13 and 1442±560 in 3/13 individuals) and in most individuals the number of SGAs changed little over time, with both increases and decreases in SGAs detected. The estimated SGA rate was 7.8 per genome per year (95% support interval [SI], 7.1–8.6) off-NSAIDs and 0.6 (95% SI 0.3–1.5) on-NSAIDs. Twelve individuals did not progress to EA. In ten we detected 279±86 SGAs affecting 53±30 Mb of the genome per biopsy per time point and in two we detected 1,463±375 SGAs affecting 180±100 Mb. In one individual who progressed to EA we detected a clone having 2,291±78 SGAs affecting 588±18 Mb of the genome at three time points in the last three of 11.4 years of follow-up. NSAIDs were associated with reduced rate of acquisition of SGAs in eleven of thirteen individuals. Barrett's cells maintained relative equilibrium level of SGAs over time with occasional punctuations by expansion of clones having massive amount of SGAs
Charge Symmetry Breaking in the Valence Quark Distributions of the Nucleon
Using a quark model, we study the effect of charge symmetry breaking on the
valence quark distributions of the nucleon. The effect due to quark mass
differences and the Coulomb interaction of the electrically charged quarks is
calculated and, in contrast to recent claims, found to be small. In addition,
we investigate the effect of charge symmetry breaking in the confining
interaction, and in the perturbative evolution equations used to relate the
quark model distributions to experiment. We find that both these effects are
small, and that the strong charge symmetry breaking effect included in the
scalar confining interactions may be distinguishable from that generated by
quark mass differences.Comment: 10 pages, LaTEX, 5 Postscript figure
Dark Heritage
Peer reviewe
- …