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Biomedical subjects

I Levine

Publications and source records attributed to I Levine.

18 recordsLinked to original sources
PubMed2006

Simulation of special bubble detectors for PICASSO.

The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.

Computer Simulation↗
PubMed2006

Direct dark matter search using large-mass superheated droplet detectors in the PICASSO experiment.

The PICASSO experiment investigates the presence and nature of dark matter in the Universe. The experiment is based on the detection of acoustic signals generated in explosive phase transitions induced by dark matter particles. This technique is an alternative more traditional detection technique like scintillation and ionisation, which are largely employed for dark matter search. One of the main advantages of this technique, besides its sensitivity to very low nuclear recoil energies (few keV), is its excellent background suppression features. A pilot experiment consisting of six superheated droplet detectors (40 g of active mass) is presently taking data at the Sudbury Neutrino Observatory (SNO) at a depth of 2000 m. We discuss the operation, calibration and data acquisition of the experiment and also the ongoing work to increase the sensitivity and the active mass of the detectors.

Cosmic Radiation↗
PubMed2004

Measurement of the total active 8B solar neutrino flux at the Sudbury Neutrino Observatory with enhanced neutral current sensitivity.

The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.

Journal Article↗
PubMed2004

Constraints on nucleon decay via invisible modes from the Sudbury Neutrino Observatory.

Data from the Sudbury Neutrino Observatory have been used to constrain the lifetime for nucleon decay to "invisible" modes, such as n-->3nu. The analysis was based on a search for gamma rays from the deexcitation of the residual nucleus that would result from the disappearance of either a proton or neutron from 16O. A limit of tau(inv)>2 x 10(29) yr is obtained at 90% confidence for either neutron- or proton-decay modes. This is about an order of magnitude more stringent than previous constraints on invisible proton-decay modes and 400 times more stringent than similar neutron modes.

Journal Article↗
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↗
PubMed1991

The Ural train-gas pipeline catastrophe: the report of the IDF medical corps assistance.

Following the destruction of two trains in the Urals 2000 km east of Moscow, as a consequence of the conflagration caused by an explosion from a leaking natural gas pipeline, 3000 people were injured;* most of them (2200) died* immediately and the others (about 800) were badly burned. At the request of the Soviet Union Government a medical military delegation was sent to give assistance to the injured people. This report describes the treatment given by the delegation to 40 patients with burns of between 40 and 90 per cent TBSA during a period of 10 days. An insight into a Soviet Union Trauma Center is given and the good treatment given by the Soviet colleagues is emphasized.

Blast Injuries↗
PubMed1990

The expression of HLA class I antigens in germ cell testicular cancer.

The expression of HLA class I antigens in testicular germ cell tumors (TGCTs) was studied by the immunoperoxidase technique. In the normal testicle, the interstitial cells of Leydig as well as most of the germ cells were significantly stained. In typical seminoma, 75% of the tumor cells in stage I and 30% in stage II were stained. In embryonal cell carcinoma, 25% of the cases in stage I and less than 10% of those in stage II were stained. Mature teratoma was stained in most of the cases, whereas in malignant teratoma only 35% of the cases showed some staining of the tumor cells. In mixed tumors each component displayed its characteristic staining pattern. The expression of class I antigens on tumor cells is required for immune recognition and lysis of the tumor by cytotoxic T-cells. The reduced expression of class I antigens that was related to histologic characteristics and stage suggests that some testicular tumors may escape immune surveillance and become biologically more aggressive.

Dysgerminoma↗
PubMed1988

Waterborne enteric disease outbreaks in Israel, 1976-1985.

Waterborne enteric disease remains a major public health problem in developing countries, as well as in developed countries, such that the World Health Organization declared 1981-90 the International Water Decade. Israeli experience with waterborne disease outbreaks in the decade 1976-85 is reviewed. Community water systems accounted for 52 outbreaks, with 25 occurring between 1976 and 1980 and 27 between 1981 and 1985. Total cases reported in these outbreaks were 7,681 and 10,880 respectively. In the latter period, reported cases resulting from these outbreaks constituted a very high percentage of the total reported cases of diarrheal disease in the country. The waterborne disease outbreaks were mostly due to secondary contamination of water systems due to human error and poor maintenance. In comparison with the United States, Israel experienced 18.7 times as many community waterborne disease outbreaks per capita. The need for routine preventive chlorination, and filtration on a selective basis, of community drinking water systems is strongly indicated, as recommended in current United States and World Health Organization guidelines in order to improve this grossly substandard aspect of Israeli public health.

Bacterial Infections↗
PubMed1985

Dynamic interpersonal processes and the inpatient holding environment.

The long-term inpatient psychiatric hospital treating severely disabled patients is a complex, multifaceted institution in which many diverse people occupying different roles interact in order to accomplish the task of creating a holding environment for the patient. In this paper, we suggest that the primary function of a psychiatric holding environment is the delivery to the patient of the normative services which the nuclear family customarily provides. In order to provide this, the hospital, like the optimal family, holds both by restraining and by facilitating. Through an understanding of the strategic mental mechanisms which severely disturbed patients often employ in order to interact with and comprehend others, particularly empathy and projective identification, we may delineate more refined treatment strategies. Principles concerning the dynamics of small and large groups, patient-staff interactions, the treatment of so-called "hopeless" and negative therapeutic reaction patients, and supervision follow from these conceptualizations. In all of our explication, our perspective is guided by a systems framework but finds concrete expression in an object relational viewpoint.

Adolescent↗