Indication of reactor ν(e) disappearance in the Double Chooz experiment

The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. An observed-to-predicted ratio of events of 0.944±0.016(stat)±0.040(syst) was obtained in 101 days of running at the Chooz nuclear power plant in France, with two 4.25 GW(th) reactors. The results were obtained from a single 10 m(3) fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 flux measurement after correction for differences in core composition. The deficit can be interpreted as an indication of a nonzero value of the still unmeasured neutrino mixing parameter sin(2)2θ(13). Analyzing both the rate of the prompt positrons and their energy spectrum, we find sin(2)2θ(13)=0.086±0.041(stat)±0.030(syst), or, at 90% C.L., 0.017<sin(2)2θ(13)<0.16.

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.

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.

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.

High sensitivity search for nu;e's from the sun and other sources at KamLAND

Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for nu;(e)'s in the energy range 8.3<E(nu;(e))<14.8 MeV. No candidates were found for an expected background of 1.1+/-0.4 events. This result can be used to obtain a limit on nu;(e) fluxes of any origin. Assuming that all nu;(e) flux has its origin in the Sun and has the characteristic 8B solar nu(e) energy spectrum, we obtain an upper limit of 3.7 x 10(2) cm(-2) s(-1) (90% C.L.) on the nu;(e) flux. We interpret this limit, corresponding to 2.8 x 10(-4) of the standard solar model 8B nu(e) flux, in the framework of spin-flavor precession and neutrino decay models.

First results from KamLAND: evidence for reactor antineutrino disappearance

KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.

Immune complexes and complement activation following rupture of intracranial saccular aneurysms

Circulating immune complexes (CIC) and complement activation (plasma C3d levels) were monitored during a 2-week period in patients with ruptured cerebral aneurysms and also in patients with cerebral hematoma unrelated to saccular aneurysms. Thirteen of 18 aneurysm patients were found to have CIC on admission as compared to three of 21 healthy blood donors (p less than 0.001). The presence of CIC in aneurysm patients was associated with a poor prognosis. Eight of nine patients who developed angiographic vasospasm had CIC on admission compared with one of four without vasospasm. Patients with vasospasm showed a twofold increase in plasma C3d levels at the time when the spasm occurred, whereas no significant changes in the C3d concentration could be demonstrated in aneurysm patients without spasm or in patients with hematoma unrelated to aneurysm rupture. These findings suggest that immunological processes involving complement-activating immune complexes are involved in the pathogenesis of cerebral vasospasm following rupture of saccular aneurysms.

The significance of preoperative radiological examinations in patients treated with Cloward's operation

During a fifteen-year period 1,106 patients with symptoms and signs of cervical disc disease underwent Cloward's operation. Plain x-rays were performed in 94%, but the severity and extension of degenerative changes had no prognostic value. In 91% of the patients myelography was performed and in recent years mainly metrizamide was used as it was found to be more accurate. The findings on the myelograms were correlated according to age, severity and number of affected disc levels, but were independent of the duration of symptoms. Patients with medullary symptoms were found more often than not to have an anterior indentation into the spinal canal whereas most patients with radicular symptoms had wide cervical root sleeves or lateral compression. The best outcome was found among patients with monosegmental symptoms and signs and one affected disc level on the myelogram underlining that the indication for surgery in cervical disc disease should be based on both clinical and radiological findings.

Dental and skeletal maturity in adoptive children: assessments at arrival and after one year in the admitting country

Seventy-one adoptive children from Asian countries, mainly Korea, were adopted by Danish parents. Height and weight were measured and dental and skeletal maturity assessed immediately after arrival and one year later. Increase in dental age was in complete concordance with the time interval between the two examinations. With regard to skeletal age, the majority of children showed an increased maturation rate although some of the youngest children seemed to be further retarded in maturation rate during their first year in Denmark. Comparison between two methods for assessing skeletal maturity revealed that the 'catch up' observed for children above one year of age was significantly more pronounced when assessed by the TW-2 method than when applying the G-P method. For the Korean children height and weight measurements increased more than the average values for the Danish population.

Predictive value of radiculography in patients with lumbago-sciatica. A prospective study (Part II)

One hundred patients with symptoms of lumbo-sacral root compression were prospectively and consecutively assigned to operation based alone on clinical findings. A preoperative myelogram was performed in all patients and described without a knowledge of the clinical features. All patients were explored for the clinically and myelographically relevant disc. When the myelogram was normal (16 patients) both lower lumbar interspaces were exposed. In 58 patients a herniated disc was revealed at surgery. Only "myelographic herniation" with indentation of the contrast column was accompanied by a high frequency of disc herniation at surgery (73-87%). In cases with normal myelograms only 5% had a disc herniation. The severity of the myelographic finding was clearly correlated to the frequency of positive surgical findings and good outcomes. The preoperative radiculogram gives a high degree of certainty in the preoperative evaluation whether a surgical lesion is present or not and reveals a precise prediction of the outcome of surgery.

Predictive value of clinical and surgical findings in patients with lumbago-sciatica. A prospective study (Part I)

In a prospective, consecutive study of patients with lumbar back pain and sciatica, various clinical features and surgical findings were evaluated in order to analyse the predictive value regarding (1) level of diseased interspace (2) presence and type of lesion responsible for root compression (3) outcome after surgery. One hundred patients underwent surgery solely on clinical grounds. Fifty-eight had disc herniation. The level of disc herniation was correctly predicted in three quarters of patients with a prolapsed disc. The outcome after surgery was good in 77 patients. Only few clinical features, namely male sex and scoliosis were predictors of a good outcome. Lasegue's sign was indicative of root compression in 90%, but only two-thirds had disc herniation. Conversely one-third had disc herniation in spite of a "negative" test. Lasegue's sign was not superior to other clinical tests in predicting outcome. The most important indicator of a good outcome was the presence of disc herniation at surgery. Patients with disc pathology other than true disc herniation fared equally with patients, who had normal discs disclosed at surgery. Myelography was undertaken in all patients prior to surgery, the results of which are analysed in the following paper. (Espersen et al.: Predictive value of radiculography in patients with lumbago-sciatica. A prospective study (Part II, Acta Neurochirurgica 73 (1984), 213-221.

[Problems in the diagnosis of pheochromocytoma (author's transl)]

Reference is made to various possibilities of examination in diagnosis and localisation of pheochromocytoma demonstrated by several cases. The best radiological examination is angiography using Seldinger method, which by means of skilled technique, good contrast media and an optimal treatment with receptor-blocking medicaments will guarantee excellent x-rays for clear tumor localisation without real complications.