Experimental investigation of geologically produced antineutrinos with KamLAND.

The detection of electron antineutrinos produced by natural radioactivity in the Earth could yield important geophysical information. The Kamioka liquid scintillator antineutrino detector (KamLAND) has the sensitivity to detect electron antineutrinos produced by the decay of 238U and 232Th within the Earth. Earth composition models suggest that the radiogenic power from these isotope decays is 16 TW, approximately half of the total measured heat dissipation rate from the Earth. Here we present results from a search for geoneutrinos with KamLAND. Assuming a Th/U mass concentration ratio of 3.9, the 90 per cent confidence interval for the total number of geoneutrinos detected is 4.5 to 54.2. This result is consistent with the central value of 19 predicted by geophysical models. Although our present data have limited statistical power, they nevertheless provide by direct means an upper limit (60 TW) for the radiogenic power of U and Th in the Earth, a quantity that is currently poorly constrained.

Bioventing pilot test results at the low point drain area, Offutt AFB, Nebraska.

The purpose of this paper was to describe the application of bioventing technology at the LPD site at Offutt AFB, Nebraska and present the results of the 15-month pilot test. The preliminary tests indicated sufficient hydrocarbon contamination was present with the necessary soil characteristics to warrant an extended bioventing pilot test. The six month in situ respiration test indicated that progress was being made in reducing the TVH concentrations and biological activity was still occurring. Laboratory analysis of the final soil samples confirmed the reduction in TRPH and BTEX concentrations indicating that the site is close to complete remediation. However, owing to reduced air flow at greater distances from the VW, more biodegradation is still needed near MPB. The reduced biodegradation at MPB could also be due to the high water tables resulting from heavy rains during the summer and fall of 1993. The local water table was above the VW and MP screens for several months. The operation of the blower will continue until the site is completely remediated. The single VW pilot test at the LPD site at Offutt AFB has proven the effectiveness of bioventing in reducing TRPH and BTEX contamination in the subsurface. The installation, operation and maintenance costs were minimal. The effectiveness of this application has resulted in three additional bioventing applications at Offutt AFB including the first, full-scale system located in the state of Nebraska.

Precision measurement of neutrino oscillation parameters with KamLAND.

The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.

Search for the invisible decay of neutrons with KamLAND.

The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the -shell energy level of (12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n--> 3v or nn--> 2v. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: tau(n--> inv) > 5.8 x 10(29) years and tau (nn--> inv) > 1.4 x 10(30) years at 90% C.L. These results represent an improvement of factors of approximately 3 and >10(4) and over previous experiments.

Measurement of neutrino oscillation with KamLAND: evidence of spectral distortion.

We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date.

Patients who leave without being seen.

We conducted this study because very little is known about patients who leave without being seen. A total of 4,868 patients were registered in an emergency department during a six-week study period. Sixty-eight (1.4%) left before treatment was completed; 97% (66 patients) left before ever being seen by a physician. Thirty of the 68 patients were interviewed later in followup A comparison group of 23 patients who did not leave prematurely was also selected and matched for age, sex, urgency of chief complaint, and time of presentation. Fourteen of these patients were interviewed later. Patients who left without being seen (LWBS) and nonLWBS patients did not differ in waiting time in the ED. The two groups also did not differ in the spectrum of chief complaints. Twenty-two of 30 LWBS patients were suffering from acute psychological distress at the time of their visit, however, compared to only one of the comparison group (P = .0005). The walkouts reported recent deaths of relatives or friends, recent bouts of alcoholism, acute financial problems, suicidal thoughts and behavior, court appearances, pregnancies and miscarriages, new people in the home, acute illnesses in relatives, and other psychological and social crises.

MMPI predictors of mania among psychiatric inpatients.

MMPI data from 64 patients with a diagnosis of manic-depressive illness, manic type, were compared with MMPI data from patients in two comparison groups--64 patients with a psychotic diagnosis other than manic-depressive illness, and 64 patients with a variety of psychiatric diagnoses. Manic patients had higher Ma scale scores for MMPI scales that assess personal distress and interpersonal difficulties (e.g., D and Si). Discriminant analysis, with the Ma, D, and Si scales as predictors, correctly classified as manic or not manic 82.5% of the patients in the derivation sample and 74.2% of the patients in the cross-validation sample. Two high-point pairs, Sc-Ma/Ma-Sc and Pa-Ma/Ma-Pa, occurred in the MMPI profiles of almost half of the manic patients but were rarely found among the profiles of other patients. The results of this study support the use of the MMPI in identifying manic patients, particularly when discriminating between mania and other types of psychosis.