826 research outputs found
Impact of calcium carbonate on the juveniles of brackish river prawn, Macrobrachium marobrachion under laboratory conditions
The acute toxicity and the effect of sub-lethal concentrations of calcium carbonate on the morphology of M. macrobrachion were investigated under laboratory conditions. The prawns were exposed at 0, 160, 320, 640, 1280, 2560 and 5120 mg/l of CaCO3 using static renewal bioassay for 96 hours for the acute toxicity test. The prawns were also exposed for the chronic test at 0, 20.0, 40.0, and 80.0 mg/1 for a period of two weeks. Mortality occurred in the bioassay tanks at random and the bioassays were monitored throughout the exposure period. Results showed that exposed prawns were not significantly impacted when compared with the control group and correlations were significant at P<0.05. There were no mortalities in the tanks with the highest concentrations while one death was recorded in the control tank and in the tank with the 160 and 320mg/1 of CaCO3 respectively. The gills of exposed prawns were analyzed using photomicrography and the results showed that the organs had their normal morphological status after the exposure time, implying that CaCO3 is non-toxic to M. macrobrachion. The applications of the result to prawn culture and water quality management were discussed in details
Food habits, sexual dimorphism and sex ratio of three Palaemonid prawns of the Nun River, Niger Delta, Nigeria
The food habits, sex ratio and differences of three freshwater prawns ? Macrobrachium vollenhovenii, M. macrobrachion and M. felicinum from Nun River, Niger Delta were studied. It was found that although the prawns had an omnivorous diet feeding on a wide range of organisms including plants, detritus, insect parts, phytoplankton and zooplankton the food habits indicate a tendency towards a plant-based (herbivorous) diet. The adult prawns exhibit sexual dimorphism with males being larger than females; however the males were fewer in number than the females with mean ratios of 1:2.79, 1:1.58 and 1:9.12 for M. vollenhovenii, M. macrobrachion and M. felicinum. Sexual dimorphism exists in the species and brood-stock are available in the Nun River system of the Niger Delta region
Homoeologous chromosomal location of the genes encoding thionins in wheat and rye
Thionins are high sulphur basic polypeptides present in the endosperm of Gramineae. In wheat there are three thionins encoded by genes located in the long arms of chromosomes 1A, 1B and 1D. Rye has one thionin encoded by a gene which has been assigned to chromosome 1R after analysis of the Imperial-Chinese Spring rye-wheat disomic addition lines. Commercial varieties and experimental stocks with a 1B/1R substitution carry the thionin from rye ( R) instead of the B thionin from wheat. The R thionin gene is not located in the large chromosomal segment representing most of the short arm of chromosome 1R
Magnetic monopoles from gauge theory phase transitions
Thermal fluctuations of the gauge field lead to monopole formation at the
grand unified phase transition in the early Universe, even if the transition is
merely a smooth crossover. The dependence of the produced monopole density on
various parameters is qualitatively different from theories with global
symmetries, and the monopoles have a positive correlation at short distances.
The number density of monopoles may be suppressed if the grand unified symmetry
is only restored for a short time by, for instance, nonthermal symmetry
restoration after preheating.Comment: 5 pages, updated to match the version published in PRD
(http://link.aps.org/abstract/PRD/v68/e021301) on 11 July 200
The primate EAE model points at EBV-infected B cells as a preferential therapy target in multiple sclerosis
The remarkable clinical efficacy of anti-CD20 monoclonal antibodies (mAb) in relapsing-remitting multiple sclerosis points at the critical involvement of B cells in the disease. However, the exact pathogenic contribution of B cells is poorly understood. In this publication we review new data on the role of CD20+ B cells in a unique experimental autoimmune encephalomyelitis (EAE) model in common marmosets (Callithrix jacchus), a small-bodied neotropical primate. We will also discuss the relevance of these data for MS. Different from rodent EAE models, but similar to MS, disease progression in marmosets can develop independent of autoantibodies. Progressive disease is mediated by MHC class Ib (Caja-E) restricte
Immersed boundary-finite element model of fluid-structure interaction in the aortic root
It has long been recognized that aortic root elasticity helps to ensure
efficient aortic valve closure, but our understanding of the functional
importance of the elasticity and geometry of the aortic root continues to
evolve as increasingly detailed in vivo imaging data become available. Herein,
we describe fluid-structure interaction models of the aortic root, including
the aortic valve leaflets, the sinuses of Valsalva, the aortic annulus, and the
sinotubular junction, that employ a version of Peskin's immersed boundary (IB)
method with a finite element (FE) description of the structural elasticity. We
develop both an idealized model of the root with three-fold symmetry of the
aortic sinuses and valve leaflets, and a more realistic model that accounts for
the differences in the sizes of the left, right, and noncoronary sinuses and
corresponding valve cusps. As in earlier work, we use fiber-based models of the
valve leaflets, but this study extends earlier IB models of the aortic root by
employing incompressible hyperelastic models of the mechanics of the sinuses
and ascending aorta using a constitutive law fit to experimental data from
human aortic root tissue. In vivo pressure loading is accounted for by a
backwards displacement method that determines the unloaded configurations of
the root models. Our models yield realistic cardiac output at physiological
pressures, with low transvalvular pressure differences during forward flow,
minimal regurgitation during valve closure, and realistic pressure loads when
the valve is closed during diastole. Further, results from high-resolution
computations demonstrate that IB models of the aortic valve are able to produce
essentially grid-converged dynamics at practical grid spacings for the
high-Reynolds number flows of the aortic root
Comparison of large-scale flows on the Sun measured by time-distance helioseismology and local correlation tracking technique
We present a direct comparison between two different techniques time-distance
helioseismology and a local correlation tracking method for measuring mass
flows in the solar photosphere and in a near-surface layer: We applied both
methods to the same dataset (MDI high-cadence Dopplergrams covering almost the
entire Carrington rotation 1974) and compared the results. We found that after
necessary corrections, the vector flow fields obtained by these techniques are
very similar. The median difference between directions of corresponding vectors
is 24 degrees, and the correlation coefficients of the results for mean zonal
and meridional flows are 0.98 and 0.88 respectively. The largest discrepancies
are found in areas of small velocities where the inaccuracies of the computed
vectors play a significant role. The good agreement of these two methods
increases confidence in the reliability of large-scale synoptic maps obtained
by them.Comment: 14 pages, 6 figures, just before acceptance in Solar Physic
Dinocyst stratigraphy and palaeoenvironmental interpretation of the Cretaceous/Paleogene boundary at Stevns Klint, Denmark
Implementation of Novel Molecular Biomarkers for Non-small Cell Lung Cancer in the Netherlands: How to Deal With Increasing Complexity
The diagnostic landscape of non-small cell lung cancer (NSCLC) is changing rapidly with the availability of novel treatments. Despite high-level healthcare in the Netherlands, not all patients with NSCLC are tested with the currently relevant predictive tumor markers that are necessary for optimal decision-making for today's available targeted or immunotherapy. An expert workshop on the molecular diagnosis of NSCLC involving pulmonary oncologists, clinical chemists, pathologists, and clinical scientists in molecular pathology was held in the Netherlands on December 10, 2018. The aims of the workshop were to facilitate cross-disciplinary discussions regarding standards of practice, and address recent developments and associated challenges that impact future practice. This paper presents a summary of the discussions and consensus opinions of the workshop participants on the initial challenges of harmonization of the detection and clinical use of predictive markers of NSCLC. A key theme identified was the need for broader and active participation of all stakeholders involved in molecular diagnostic services for NSCLC, including healthcare professionals across all disciplines, the hospitals and clinics involved in service delivery, healthcare insurers, and industry groups involved in diagnostic and treatment innovations. Such collaboration is essential to integrate different technologies into molecular diagnostics practice, to increase nationwide patient access to novel technologies, and to ensure consensus-preferred biomarkers are tested
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