9,252 research outputs found
Solid rocket booster internal flow analysis by highly accurate adaptive computational methods
The primary objective of this project was to develop an adaptive finite element flow solver for simulating internal flows in the solid rocket booster. Described here is a unique flow simulator code for analyzing highly complex flow phenomena in the solid rocket booster. New methodologies and features incorporated into this analysis tool are described
Defining the complementarities between antibodies and haptens to refine our understanding and aid the prediction of a successful binding interaction
Acknowledgments The authors would like to thank the Scottish Universities Life Sciences Alliance (SULSA) for their support.Peer reviewedPublisher PD
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Fast three dimensional r-adaptive mesh redistribution
This paper describes a fast and reliable method for redistributing a computational mesh in three dimensions which can generate a complex three dimensional mesh without any problems due to mesh tangling. The method relies on a three dimensional implementation of the parabolic Monge–Ampère (PMA) technique, for finding an optimally transported mesh. The method for implementing PMA is described in detail and applied to both static and dynamic mesh redistribution problems, studying both the convergence and the computational cost of the algorithm. The algorithm is applied to a series of problems of increasing complexity. In particular very regular meshes are generated to resolve real meteorological features (derived from a weather forecasting model covering the UK area) in grids with over 2×107 degrees of freedom. The PMA method computes these grids in times commensurate with those required for operational weather forecasting
Remembering Another Aspect of Forgetting
Although forgetting is most often thought of in terms of declines in performance (response loss or impairment), another class of memory phenomena, the forgetting of stimulus attributes, has begun to attract experimental attention. In non-human animals, the loss of memory for stimulus features is reflected in the flattening of stimulus generalization gradients as well as in the attenuation of the disrupting effect of a shift in context at testing. In both cases, a delay between the learning episode and testing results in increased responding in the presence of previously ineffective stimuli. Thus, previously discriminable cues become more functionally interchangeable. The implications of the forgetting of attributes for some theoretical issues of memory loss and for methodological strategies have been noted earlier. However, relatively little is known about the neurobiological mechanisms underlying stimulus attribute forgetting, and why some memories are maintained while others are not. In this paper we review the evidence for the forgetting of stimulus attributes, discuss recent findings identifying neurobiological underpinnings of forgetting and generalization of fear responses, and discuss relevant clinical implications of fear generalization
Management preferences in stage I non-seminomatous germ cell tumours of the testis: an investigation among patients, controls and oncologists.
Increasingly, treatment choices leading to the same survival outcome can be offered to cancer patients (e.g. mastectomy or conservative surgery in early breast cancer). Two approaches available for post-orchidectomy, stage I patients with non-seminomatous germ cell tumours of the testis (NSGCTT), particularly those at high risk of relapse, include immediate adjuvant chemotherapy (two courses) or surveillance, with chemotherapy (typically four courses) given only on relapse. The aim of this study was to investigate which approach patients prefer. Questionnaires were given to newly diagnosed NSGCTT patients, to patients with previous experience of the two options and to non-cancer controls, including specialist testicular tumour oncologists. Participants were asked to choose between immediate chemotherapy, surveillance or for the doctor to decide, at recurrence risk levels ranging from 10% to 90%. Questionnaires were returned by 207 subjects in nine different groups. The risk thresholds at which subjects' management preference changed, within apparently homogeneous groups, varied greatly, although at least one subject in each group selected adjuvant chemotherapy at the lowest (10%) level of risk. Subjects tended to favour options of which they had previous experience. Cancer patients wanted the doctor to decide more frequently than controls. The wide variability observed makes it difficult to predict which option an individual will select. Personality factors and personal circumstances, other than specific experience and knowledge, are obviously influential. Many patients would prefer their doctor to decide, but variability among oncologists is as great as that among their patients
NHK-1 phosphorylates BAF to allow karyosome formation in the Drosophila oocyte nucleus
Accurate chromosome segregation in meiosis requires dynamic changes in chromatin organization. In Drosophila melanogaster, upon completion of recombination, meiotic chromosomes form a single, compact cluster called the karyosome in an enlarged oocyte nucleus. This clustering is also found in humans; however, the mechanisms underlying karyosome formation are not understood. In this study, we report that phosphorylation of barrier to autointegration factor (BAF) by the conserved kinase nucleosomal histone kinase-1 (NHK-1; Drosophila Vrk1) has a critical function in karyosome formation. We find that the noncatalytic domain of NHK-1 is crucial for its kinase activity toward BAF, a protein that acts as a linker between chromatin and the nuclear envelope. A reduction of NHK-1 or expression of nonphosphorylatable BAF results in ectopic association of chromosomes with the nuclear envelope in oocytes. We propose that BAF phosphorylation by NHK-1 disrupts anchorage of chromosomes to the nuclear envelope, allowing karyosome formation in oocytes. These data provide the first mechanistic insight into how the karyosome forms
Schottky mass measurements of heavy neutron-rich nuclides in the element range 70\leZ \le79 at the ESR
Storage-ring mass spectrometry was applied to neutron-rich Au
projectile fragments. Masses of Lu, Hf, Ta,
W, and Re nuclei were measured for the first time. The
uncertainty of previously known masses of W and Os nuclei
was improved. Observed irregularities on the smooth two-neutron separation
energies for Hf and W isotopes are linked to the collectivity phenomena in the
corresponding nuclei.Comment: 10 pages, 9 figures, 2 table
Differential effects of TFG-β and FGF-2 on in vitro proliferation and migration of primate retinal endothelial and Müller cells
Purpose: During retinal development, the pattern of blood vessel formation depends upon the combined effects of proliferation and migration of endothelial cells, astrocytes and Müller cells. In this study, we investigated the potential for transforming
mini spindles: A Gene Encoding a Conserved Microtubule-Associated Protein Required for the Integrity of the Mitotic Spindle in Drosophila
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle
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