136 research outputs found
Production of spectator hypermatter in relativistic heavy-ion collisions
We study the formation of large hyper-fragments in relativistic heavy-ion
collisions within two transport models, DCM and UrQMD. Our goal is to explore a
new mechanism for the formation of strange nuclear systems via capture of
hyperons by relatively cold spectator matter produced in semi-peripheral
collisions. We investigate basic characteristics of the produced
hyper-spectators and evaluate the production probabilities of multi-strange
systems. Advantages of the proposed mechanisms over an alternative coalescence
mechanism are analysed. We also discuss how such systems can be detected taking
into account the background of free hyperons. This investigation is important
for the development of new experimental methods for producing hyper-nuclei in
peripheral relativistic nucleus-nucleus collisions, which are now underway at
GSI and are planned for the future FAIR and NICA facilities.Comment: 28 pages, including 10 figures. Submitted to Phys. Rev.
Elastic constants of borocarbides. New approach to acoustic Measurement technique
A new version of the phase method of determining the sound velocity is
proposed and implemented. It utilizes the ``Nonius'' measurement technique and
can give acceptable accuracy (~1%) in samples of submillimeter size.
Measurements of the sound velocity are made in single-crystal samples of the
borocarbides RNi2B2C (R = Y,Lu,Ho). The elastic constants and the Debye
temperature are calculated.Comment: 5 figures, 2 table
Ferromagnetism in Co-doped ZnO films grown by molecular beam epitaxy: magnetic, electrical and microstructural studies
We studied structural, optical and magnetic properties of high-quality 5 and
15% Co-doped ZnO films grown by plasma-assisted molecular beam epitaxy (MBE) on
(0001)-sapphire substrates. Magnetic force microscopy (MFM) and magnetic
measurements with SQUID magnetometer show clear ferromagnetic behavior of the
films up to room temperature whereas they are antiferromagnetic below 200 K
approximately. Temperature dependence of the carrier mobility was determined
using Raman line shape analysis of the longitudinal-optical-phonon-plasmon
coupled modes. It shows that the microscopic mechanism for ferromagnetic
ordering is coupling mediated by free electrons between spins of Co atoms.
These results bring insight into a subtle interplay between charge carriers and
magnetism in MBE-grown Zn(1-x)CoxO films.Comment: 10 pages, 9 figures, 2 table
Strangeness nuclear physics: a critical review on selected topics
Selected topics in strangeness nuclear physics are critically reviewed. This
includes production, structure and weak decay of --Hypernuclei, the
nuclear interaction and the possible existence of bound
states in nuclei. Perspectives for future studies on these issues are also
outlined.Comment: 63 pages, 51 figures, accepted for publication on European Physical
Journal
From Senseless to Sensory Democracy: Insights from Applied and Participatory Theatre
This article seeks to stimulate a fresh and inter-disciplinary debate which revolves
around the need to move from a ‘senseless democracy’ that is insufficiently attuned to the
dilemmas and challenges of fostering meaningful political engagement to a more ‘sensory
democracy’. It achieves this by first exploring and dissecting recent works within democratic
theory that emphasize the role of ‘watching’ and ‘listening’ within socio-political
relationships. It then goes on to develop a set of constructive criticisms by applying insights
drawn from the fields of practical aesthetics and applied theatre. Not only does this exercise
allow us to take the analytical lens far beyond the focus on voice-based forms of expression
that have hitherto dominated political analysis, it demonstrates the value of inter-disciplinary
scholarship in exposing sensory-subtleties that raise distinctive questions for both politics ‘as
theory’ and politics ‘as practice’
Exposure from the Chernobyl accident had adverse effects on erythrocytes, leukocytes, and, platelets in children in the Narodichesky region, Ukraine: A 6-year follow-up study
<p>Abstract</p> <p>Background</p> <p>After the Chernobyl nuclear accident on April 26, 1986, all children in the contaminated territory of the Narodichesky region, Zhitomir Oblast, Ukraine, were obliged to participate in a yearly medical examination. We present the results from these examinations for the years 1993 to 1998. Since the hematopoietic system is an important target, we investigated the association between residential soil density of <sup>137</sup>Caesium (<sup>137</sup>Cs) and hemoglobin concentration, and erythrocyte, platelet, and leukocyte counts in 1,251 children, using 4,989 repeated measurements taken from 1993 to 1998.</p> <p>Methods</p> <p>Soil contamination measurements from 38 settlements were used as exposures. Blood counts were conducted using the same auto-analyzer in all investigations for all years. We used linear mixed models to compensate for the repeated measurements of each child over the six year period. We estimated the adjusted means for all markers, controlling for potential confounders.</p> <p>Results</p> <p>Data show a statistically significant reduction in red and white blood cell counts, platelet counts and hemoglobin with increasing residential <sup>137</sup>Cs soil contamination. Over the six-year observation period, hematologic markers did improve. In children with the higher exposure who were born before the accident, this improvement was more pronounced for platelet counts, and less for red blood cells and hemoglobin. There was no exposure×time interaction for white blood cell counts and not in 702 children who were born after the accident. The initial exposure gradient persisted in this sub-sample of children.</p> <p>Conclusion</p> <p>The study is the first longitudinal analysis from a large cohort of children after the Chernobyl accident. The findings suggest persistent adverse hematological effects associated with residential <sup>137</sup>Cs exposure.</p
Inborn errors of OAS-RNase L in SARS-CoV-2-related multisystem inflammatory syndrome in children
Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the single-stranded RNA-degrading ribonuclease L (RNase L). Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-deficient but not RNase L-deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by mitochondrial antiviral-signaling protein (MAVS) deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C
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