517 research outputs found

    Accurate simultaneous lead stopping power and charge-state measurements in gases and solids:Benchmark data for basic atomic theory and nuclear applications

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    We have measured for the first time simultaneously both the mean charge states and stopping powers of (35–280) MeV/u 208Pb ions in gases and solids with an accuracy of 1%. The existence at lower energies and disappearance at higher of density effects in the charge-state distribution and the corresponding stopping power are directly confirmed and comparisons with widely used theories and simulations for heavy ions demonstrate strong deviations of up to 27%. However, an unprecedented prediction power of better than 3% has been achieved for the energy loss when the measured mean charge-states are implemented in the Lindhard-Sørensen theory. Our present benchmark data contribute to an improved understanding of the basic atomic collision processes and to numerous applications in nuclear physics. Extending the GANIL data [1] to higher accuracy and energies, we can now answer at which velocities the Bohr-Lindhard density effect in stopping will vanish.</p

    Spectroscopy of η<sup>0</sup>-mesic nuclei with WASA at GSI/FAIR

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    We plan to conduct an experimental search for η0-mesic nuclei in order to investigate in-medium properties of the η0 meson. A 2.5 GeV proton beam is employed to produce η0-mesic 11C nuclei with the 12C(p,d)η0⊗ 11C reaction. Simultaneous measurements of the forward ejected deuterons and decay protons from η0-mesic nuclei will allow us to achieve high experimental sensitivity. The experiment will be performed at GSI by making full use of the fragment separator FRS and the WASA detector system. The plan of this proposed experiment is described.</p

    Symbiotic stars in the Local Group of Galaxies

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    Preliminary results of the ongoing search for symbiotic binary stars in the Local Group of Galaxies are presented and discussed.Comment: Proceedings of Physics of Evolved Stars 2015: A Conference Dedicated to the Memory of Olivier Chesneau, Nice, 8-12 June 201

    Studies of three-and four-body hypernuclei with heavy-ion beams, nuclear emulsions and machine learning

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    Interests on few-body hypernuclei have been increased by recent results of experiments employing relativistic heavy ion beams. Some of the experiments have revealed that the lifetime of the lightest hypernucleus, hypertriton, is significantly shorter than 263 ps which is expected by considering the hypertriton to be a weakly-bound system. The STAR collaboration has also measured the hypertriton binding energy, and the deduced value is contradicting to its formerly known small binding energy. These measurements have indicated that the fundamental physics quantities of the hypertriton such as its lifetime and binding energy have not been understood, therefore, they have to be measured very precisely. Furthermore, an unprecedented Λnn bound state observed by the HypHI collaboration has to be studied in order to draw a conclusion whether or not such a bound state exists. These three-body hypernuclear states are studied by the heavy-ion beam data in the WASA-FRS experiment and by analysing J-PARC E07 nuclear emulsion data with machine learning.</p

    WASA-FRS EXPERIMENTS IN FAIR PHASE-0 AT GSI

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    We have developed a new and unique experimental setup integrating the central part of the Wide Angle Shower Apparatus (WASA) into the Fragment Separator (FRS) at GSI. This combination opens up possibilities of new experiments with high-resolution spectroscopy at forward 0◦ and measurements of light decay particles with nearly full solid-angle acceptance in coincidence. The first series of the WASA-FRS experiments have been successfully carried out in 2022. The developed experimental setup and two physics experiments performed in 2022 including the status of the preliminary data analysis are introduced.</p

    Magnetostimulated inhomogeneity of electric field in aluminum

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    The results of low temperature experimental and theoretical study of potential distribution of stationary electric field in Al under the action of inhomogeneous magnetic field are presented

    Genetic approaches to the investigation of serotonergic neuron functions in animals

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    The serotonergic system is one of the most important neurotransmitter systems that take part in the regulation of vital CNS functions. The understanding of its mechanisms will help scientists create new therapeutic approaches to the treatment of mental and neurodegenerative diseases and find out how this neurotransmitter system interacts with other parts of the brain and regulates their activity. Since the serotonergic system anatomy and functionality are heterogeneous and complex, the best tools for studying them are based on manipulation of individual types of neurons without affecting neurons of other neurotransmitter systems. The selective cell control is possible due to the genetic determinism of their functions. Proteins that determine the uniqueness of the cell type are expressed under the regulation of cell-specific promoters. By using promoters that are specific for genes of the serotonin system, one can control the expression of a gene of interest in serotonergic neurons. Here we review approaches based on such promoters. The genetic models to be discussed in the article have already shed the light on the role of the serotonergic system in modulating behavior and processing sensory information. In particular, genetic knockouts of serotonin genes sert, pet1, and tph2 promoted the determination of their contribution to the development and functioning of the brain. In addition, the review describes inducible models that allow gene expression to be controlled at various developmental stages. Finally, the application of these genetic approaches in optogenetics and chemogenetics provided a new resource for studying the functions, discharge activity, and signal transduction of serotonergic neurons. Nevertheless, the advantages and limitations of the discussed genetic approaches should be taken into consideration in the course of creating models of pathological conditions and developing pharmacological treatments for their correction

    On the appearance of space temperature electric structures in hyperconductors under high magnetic fields

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    As part of the study of low temperature galvanomagnetic properties of high purity A1 in the Corbino geometry the voltage-current characteristics (IV) under external transverse magnetic field in the regime of given current revealed the effects of voltage stabilization. Here we attempt to ascribe these phenomena to appearance in the sample of bulk temperature structures characteristic of highly nonequilibrium systems. Joule’s heat of flowing electric current gives rise to disk warming. We also discuss the problems of the influence of warming in disks on the phenomena of electric transport with allowance for own magnetic fields being generated in disk

    The reproductive system of breast organs in cows and evaluation the function using a mineral adaptogen

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    Infertility problems still remain an urgent task of practical veterinary medicine. There are many drugs known to have an effect on the organs of the reproductive system, but the search for universal remedies is a priority. The effectiveness of drugs that prevent infertility can be assessed by reducing infertility days and reducing the cost of purchasing sperm products. Restoration, enhancement and prolongation of lactation also ensures the effectiveness of dairy cattle breeding. Therefore, the search for effective means of prevention and treatment is the purpose of this study. The article describes the results of research on the effect of mineral adaptogen on the function of the reproductive system and breast organs in cows. The article presents the results of changes in hematological and biochemical blood tests in cows receiving adaptogen during the dry period and the state of the reproductive system, breast and milk productivity, against the background of taking adaptogen. As a result of the conducted research, a decrease in the incidence of reproductive organs and udders was noted. Reduction of complications in childbirth and the postpartum period. A decrease in the incidence of neonatal pathology in newborn calves was noted. In addition, an increase in dairy productivity

    Transfer of optogenetic vectors into the brain of neonatal animals to study neuron functions during subsequent periods of development

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    Optogenetics, that is, the control of cell activity using light-sensitive ion channels opsins with light of a specific wavelength, is increasingly being used to study activities and functions of neurons. Expression of opsins in the cell membrane, followed by the acquisition by the cell of the sensitivity to light is achieved by means of viral vectors, often created on the basis of lentiviral or adeno-associated (AAV) viruses bearing the nucleotide sequence encoding the photo-channel proteins. Inclusion of the cell-specific promoter of interest into the transgene-expression cassette allows opsin to be produced only in the target cells. The aim of this work was to briefly describe the optogenetic method, as well as to analyze the possibility to use administration of viral vectors into the brain of neonatal animals to study the function of neurons in vivo during subsequent periods of development. In this analysis, 3-day-old rat pups received intracerebroventricular injections of optovector (pAAV-CAMKIIa-ChR2h134-YFP), coding for a photo channel, which activates neurons, and the yellow fluorescent marker protein under the CAMKIIa promoter specific for glutamatergic neurons under cold anesthesia. The peak expression of the transferred gene is usually achieved at week 3–5 after the transfer of the vector, which is what was also observed in our experiments. Stimulation of the hippocampal neurons with blue light in the 20-day-old animals, to which opto-vector was transferred at the 3rd day of life, increased the discharge activity of these neurons. This light stimulation increased expression of the recognized marker of neuronal activation protein c-Fos in these photosensitive cells too. The same experiments with older animals, 60 days after the neonatal opto-channel gene transfer, revealed no noticeable expression of this channel or photoactivation of target neurons of the hippocampus. Thus, neonatal administration of a viral vector carrying an opto-channel gene is suitable for the study of brain neurons in rats of juvenile age, and requires additional control for gene expression during subsequent periods of development
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