Large enhancement of radiative strength for soft transisitons in the quasicontinuum

Radiative strength functions (RSFs) for the 56,57-Fe nuclei below the separation energy are obtained from the 57-Fe(3-He,alpha gamma)56-Fe and 57-Fe(3-He,3-He' gamma)57-Fe reactions, respectively. An enhancement of more than a factor of ten over common theoretical models of the soft (E_gamma ~< 2 MeV) RSF for transitions in the quasicontinuum (several MeV above the yrast line) is observed. Two-step cascade intensities with soft primary transitions from the 56-Fe(n,2gamma)57-Fe reaction confirm the enhancement.Comment: 4 pages including 3 figure

Partial level density of the n-quasiparticle excitations in the nuclei of the 39< A <201 region

Level density and radiative strength functions are obtained from the analysis of two-step cascades intensities following the thermal neutrons capture. The data on level density are approximated by the sum of the partial level densities corresponding to n quasiparticles excitation. The most probable values of the collective enhancement factor of the level density are found together with the thresholds of the next Cooper nucleons pair breaking. These data allow one to calculate the level density of practically any nucleus in given spin window in the framework of model concepts, taking into account all known nuclear excitation types. The presence of an approximation results discrepancy with theoretical statements specifies the necessity of rather essentially developing the level density models. It also indicates the possibilities to obtain the essentially new information on nucleon correlation functions of the excited nucleus from the experiment.Comment: 29 pages, 8 figures, 2 table

Ecosystem and human health assessment to define environmental management strategies: The case of long-term human impacts on an Arctic lake

Abstract There are rich deposits of mineral and fossil natural resources in the Arctic, which make this region very attractive for extracting industries. Their operations have immediate and vast consequences for ecological systems, which are particularly vulnerable in this region. We are developing a management strategy for Arctic watersheds impacted by industrial production. The case study is Lake Imandra watershed (Murmansk oblast, Russia) that has exceptionally high levels of economic development and large numbers of people living there. We track the impacts of toxic pollution on ecosystem health and then -human health. Three periods are identified: (a) natural, pre-industrial state; (b) disturbed, under rapid economic development; and (c) partial recovery, during recent economic meltdown. The ecosystem is shown to transform into a qualitatively new state, which is still different from the original natural state, even after toxic loadings have substantially decreased. Fish disease where analyzed to produce and integral evaluation of ecosystem health. Accumulation of heavy metals in fish is correlated with etiology of many diseases. Dose-effect relationships are between integral water quality indices and ecosystem health indicators clearly demonstrates that existing water quality standards adopted in Russia are inadequate for Arctic regions. Health was also poor for people drinking water from the Lake. Transport of heavy metals from drinking water, into human organs, and their effect on liver and kidney diseases shows the close connection between ecosystem and human health. A management system is outlined that is based on feedback from indices of ecosystem and human health and control over economic production and/or the amount of toxic loading produced. We argue that prospects for implementation of such a system are quite bleak at this time, and that more likely we will see a continued depopulation of these Northern regions

СТРУКТУРНО-ФУНКЦИОНАЛЬНАЯ ХАРАКТЕРИСТИКА ПЕРИФОКАЛЬНОЙ ЗОНЫ КОРЫ БОЛЬШОГО МОЗГА В ОСТРОМ ПЕРИОДЕ ЧЕРЕПНО-МОЗГОВОЙ ТРАВМЫ

The paper shows that the treatment of brain traumatic lesions is a topical problem. Moreover, the complications associated with the development of cerebral recompression play a particular role in the posttraumatic period. The purpose of the present study was to reveal the regularities of reorganization of cyto- and synaptoarchitectonics of different layers of the cerebral cortex in patients with cerebral recompression in the acute period of brain injury. Cerebral cortical biopsy specimens taken in 6 patients from the perifocal area (subdural hematoma and a contusion focus with intracerebral hematoma) were examined. The results were statistically processed, by using a package of the applied programs «StatSoft Statistica 6.0». Based on the findings, the authors suggest that it is necessary to make an early diagnosis and a complex intervention that promotes the improvement of the ultimate results of treatment.В статье показана актуальность проблемы лечения травматических повреждений головного мозга. При этом в посттравматическом периоде особую роль играют осложнения, связанные с развитием повторного сдавления головного мозга. Целью настоящего исследования было выявление закономерностей реорганизации цито- и синаптоархитектоники различных слоев коры большого мозга у пациентов с повторным сдавливанием головного мозга в остром периоде черепно-мозговой травмы. Изучены биоптаты коры головного мозга, взятые у 6 больных из перифокальной зоны (субдуральная гематома и контузионный очаг с внутримозговой гематомой). Статистическую обработку полученного материала проводили с помощью пакета прикладных программ «StatSoft Statistica 6.0». На основании полученных данных выдвигаются предложения по необходимости ранней диагностики и проведению комплексного вмешательства, способствующего улучшению конечных результатов лечения

Collimation of a Circulating Beam in the U_70 Synchrotron by Use of Reflections in Axially - Oriented Crystals

The possibilities of the extraction and collimation of a circulating beam by a new method due to the reflection of particles in crystals with axial orientation were experimentally investigated in the Fall-2010 run at the U_70 synchrotron. Such crystals have positive features, because the axial potential is five times larger than the planar potential. It has been shown that the collimation efficiency can reach 90% due to axial effects in the crystal. Losses of the circulating beam on a collimator have been reduced by several times; this makes it possible to suppress the muon jet near the steel collimator of the circulating beam.Comment: 6 pages, 7 figure

Attempt to produce element 120 in the 244 Pu + 58 Fe reaction

An experiment aimed at the synthesis of isotopes of element 120 has been performed using the 244 Pu( 58 Fe,xn) 302−x 120 reaction. No decay chains consistent with fusion-evaporation reaction products were observed during an irradiation with a beam dose of 7.1 × 10 18 330-MeV 58 Fe projectiles. The sensitivity of the experiment corresponds to a cross section of 0.4 pb for the detection of one decay