Biomedical subjects

T C Andersen

Publications and source records attributed to T C Andersen.

5 recordsLinked to original sources

PubMed2002

Direct evidence for neutrino flavor transformation from neutral-current interactions in the Sudbury Neutrino Observatory.

Observations of neutral-current nu interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard 8B shape, the nu(e) component of the 8B solar flux is phis(e) = 1.76(+0.05)(-0.05)(stat)(+0.09)(-0.09)(syst) x 10(6) cm(-2) s(-1) for a kinetic energy threshold of 5 MeV. The non-nu(e) component is phi(mu)(tau) = 3.41(+0.45)(-0.45)(stat)(+0.48)(-0.45)(syst) x 10(6) cm(-2) s(-1), 5.3sigma greater than zero, providing strong evidence for solar nu(e) flavor transformation. The total flux measured with the NC reaction is phi(NC) = 5.09(+0.44)(-0.43)(stat)(+0.46)(-0.43)(syst) x 10(6) cm(-2) s(-1), consistent with solar models.

Journal Article↗

PubMed2002

Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters.

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

Journal Article↗

PubMed2001

Measurement of the rate of nu(e) + d --> p + p + e(-) interactions produced by (8)B solar neutrinos at the Sudbury Neutrino Observatory.

Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1).

Journal Article↗

PubMed1999

Fat and mesenteric blood flow.

BACKGROUND: The introduction of fat to the duodenum leads to an increase in mesenteric blood flow. The exact mechanism, however, is unknown. In this study we investigate the influence of the terminal carboxy group of the oleic acid molecule on superior mesenteric artery blood flow. METHODS: In six healthy male volunteers duplex ultrasound was used to evaluate the effects of duodenal perfusion of 48 mmol oleic acid and 48 mmol oleyl alcohol on superior mesenteric artery blood flow variables and diameter. RESULTS: The blood flow variables time-average velocity and maximal diastolic velocity increased significantly, and the resistance index decreased significantly during perfusion with oleic acid, but during oleyl alcohol perfusion no changes were found. No significant changes in vessel diameter were observed at any time. CONCLUSION: The carboxy group of the oleic acid molecule has an important role in the duodenum in mediating the postprandial increase in superior mesenteric artery blood flow.

Adult↗

PubMed1998

Lycopodium spores in transrectal ultrasound-guided core biopsies of the prostate.

Lycopodium clavatum (LC) spores were found in two cases in transrectal ultrasound-guided core biopsies of the prostate. The source turned out to be the coating of the condoms used for protection of the ultrasound probe. To minimize confusion in analyzing the biopsies and to avoid granulomas of the prostate, LC spore-free condoms are available and are recommended for the biopsy procedure.

Aged↗