26 research outputs found
Search for the Rare Decay KL --> pi0 ee
The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay
KL--> pi0ee. This mode is expected to have a significant CP violating
component. The measurement of its branching ratio could support the Standard
Model or could indicate the existence of new physics. This letter reports new
results from the 1999-2000 data set. One event is observed with an expected
background at 0.99 +/- 0.35 events. We set a limit on the branching ratio of
3.5 x 10^(-10) at the 90% confidence level. Combining the results with the
dataset taken in 1997 yields the final KTeV result: BR(KL --> pi0 ee) < 2.8 x
10^(-10) at 90% CL.Comment: 4 pages, three figure
Effect of ivacaftor on mucociliary clearance and clinical outcomes in cystic fibrosis patients with G551D-CFTR
BACKGROUND: The ability to restore cystic fibrosis transmembrane regulator (CFTR) function with effective small molecule modulators in patients with cystic fibrosis provides an opportunity to study relationships between CFTR ion channel function, organ level physiology, and clinical outcomes. METHODS: We performed a multisite, prospective, observational study of ivacaftor, prescribed in patients with the G551D-CFTR mutation. Measurements of lung mucociliary clearance (MCC) were performed before and after treatment initiation (1 and 3 months), in parallel with clinical outcome measures. RESULTS: Marked acceleration in whole lung, central lung, and peripheral lung MCC was observed 1 month after beginning ivacaftor and was sustained at 3 months. Improvements in MCC correlated with improvements in forced expiratory volume in the first second (FEV1) but not sweat chloride or symptom scores. CONCLUSIONS: Restoration of CFTR activity with ivacaftor led to significant improvements in MCC. This physiologic assessment provides a means to characterize future CFTR modulator therapies and may help to predict improvements in lung function. TRIAL REGISTRATION: ClinicialTrials.gov, NCT01521338. FUNDING: CFF Therapeutics (GOAL11K1)
Measurements Of The Decay Kl → E+e-μ+μ-
Several 132 KL → e+e- μ+ μ- events were observed from the 1997 and 1999 runs of the KTeV experiments, with an estimated background of 0.8 events. In the first measurement of the parameter α using this decay mode, it was found that α=-1.59±0.37. No evidence was found for CP-violating contributions to the KLγ*γ* interaction.9014141801/1141801/5Wolfenstein, L., (1983) Phys. Rev. Lett., 51, p. 1945Belanger, G., Geng, C.Q., (1991) Phys. Rev. D, 43, p. 140Buras, A.J., Fleischer, R., (1998) Advanced Ser. Direct. High Energy Phys., 15, p. 65Uy, Z.E.S., (1991) Phys. Rev. D, 43, p. 802D'Ambrosio, G., Isidori, G., Portolès, J., (1998) Phys. Lett. B, 423, p. 385Alavi-Harati, A., (2001) Phys. Rev. Lett., 87, p. 71801. , KTeV CollaborationAlavi-Harati, A., (2001) Phys. Rev. Lett., 86, p. 5425. , KTeV CollaborationUy, Z.E.S., (2002) Eur. Phys. J. C, 23, p. 113Alavi-Harati, A., (2001) Phys. Rev. Lett., 87, p. 111802. , KTeV CollaborationHamm, J.C., (2002), Ph.D. thesis, The University of Arizona(Fermilab Report No. fERMILAB-THESIS-2002-09)Alavi-Harati, A., (1999) Phys. Rev. Lett., 83, p. 922. , KTeV CollaborationAlavi-Harati, A., (2000) Phys. Rev. D, 61, p. 072006. , KTeV CollaborationBrown, C., (1996) Nucl. Instrum. Methods Phys. Res., Sect. A, 369, p. 248Quinn, G.B., (2000), Ph.D. thesis, The University of ChicagoBarker, A.R., Huang, H., Toale, P.A., Engle, J., hep-ph/0210174Bergström, L., Massó, E., Singer, P., (1983) Phys. Lett., 131 B, p. 229Fanti, V., (1999) Phys. Lett. B, 458, p. 553. , NA48 Collaboratio
Microbially induced sedimentary structures in the Paleoproterozoic, upper Huronian Supergroup, Canada
The Paleoproterozoic Waterberg Group, South Africa: Provenance and its relation to the timing of the Limpopo orogeny
Four Paleoproterozoic formations of the Waterberg Group in South Africa are composed of coarse clastic
detritus derived from erosion of the Limpopo Belt. Timing of the Limpopo orogeny, an event involving
the collision of the Kaapvaal and Zimbabwe cratons, has long been a contentious issue. The results of
point counting, major and trace element geochemistry, and U–Pb detrital zircon geochronology indicate
that the Waterberg sedimentary formations in the study area were primarily sourced by siliceous (rifted
margin) sedimentary and minor mafic volcanic rocks of the Archean Beit Bridge Complex, Limpopo Central
Zone.
The volumetrically predominant beige/brown sandstones in the four studied formations are quartzrich
with average QFR ratios of 80:7:13 (Blouberg), 70:19:11 (Setlaole), 88:5:7 (Makgabeng), and 89:3:8
(Mogalakwena). Chert and arenite account for >90% of lithic fragments in all formations, with minor
siliceous gneiss fragments. Although all formations are silica enriched, the Makgabeng dune samples
produce extremely high SiO2 abundances (92–99 wt%), which are attributed to the presence of silica
cement and quartz within rock fragments. Geochemically, the stratigraphically highest Mogalakwena
Formation is unique with elevated Ti and Zr values, and intra-formational differences in REE patterns; the
latter feature is consistent with a mixed provenance. Volumetrically minor green and purple sandstones
in the Waterberg formations contain the greatest Cr, Ni, Ti, and V abundances, which supports localized
derivation from a mafic or ultramafic source. Chemical index of alteration (CIA) values range from 57
to 89, which could indicate significant chemical weathering of the source rocks, but a plot of Th/Sc
versus Zr/Sc illustrates that the sandstones have undergone recycling, which was probably responsible
for enrichments in Al2O3 relative to Na2O3, CaO and K2O. Combinations of well rounded and subangular
quartz grains support a recycled origin. Detrital zircons in the lowermost Blouberg Formation produced a
wide array of ages ranging from ca. 3379 to 2043 Ma. The youngest peak at 2046 Ma is also the largest, and
represents the maximum age of deposition for the formation. Additional peaks at 3281 Ma, 3330 Ma, and
3379 Ma are consistent with ages previously determined from the Beit Bridge Complex, whereas peaks
at 2578 Ma and 2649 Ma coincide with ages determined from gneisses of the Limpopo Central Zone.
Derivation of detritus from the Beit Bridge Complex is directly indicated by sedimentary and siliceous
gneiss fragments in the sandstones, subrounded quartz grains suggestive of relatively short transport distances,
green and purple sandstone drapes derived from mafic volcanic units, and paleocurrent patterns
consistent with south to southwest flow directions. Therefore the timing of deposition of the Blouberg
Formation (2046 Ma) equates to the end stages of the Limpopo orogeny. This negates previous suggestions
that the Limpopo orogeny occurred only during the Neoarchean.http://www.elsevier.com/locate/precamreshb201