90 research outputs found
Observability of characteristic binary-induced structures in circumbinary disks
Context: A substantial fraction of protoplanetary disks forms around stellar
binaries. The binary system generates a time-dependent non-axisymmetric
gravitational potential, inducing strong tidal forces on the circumbinary disk.
This leads to a change in basic physical properties of the circumbinary disk,
which should in turn result in unique structures that are potentially
observable with the current generation of instruments.
Aims: The goal of this study is to identify these characteristic structures,
to constrain the physical conditions that cause them, and to evaluate the
feasibility to observe them in circumbinary disks.
Methods: To achieve this, at first two-dimensional hydrodynamic simulations
are performed. The resulting density distributions are post-processed with a 3D
radiative transfer code to generate re-emission and scattered light maps. Based
on these, we study the influence of various parameters, such as the mass of the
stellar components, the mass of the disk and the binary separation on
observable features in circumbinary disks.
Results: We find that the Atacama Large (sub-)Millimetre Array (ALMA) as well
as the European Extremely Large Telescope (E-ELT) are capable of tracing
asymmetries in the inner region of circumbinary disks which are affected most
by the binary-disk interaction. Observations at submillimetre/millimetre
wavelengths will allow the detection of the density waves at the inner rim of
the disk and the inner cavity. With the E-ELT one can partially resolve the
innermost parts of the disk in the infrared wavelength range, including the
disk's rim, accretion arms and potentially the expected circumstellar disks
around each of the binary components
The dynamics of ovine gastrointestinal nematode infections within ewe and lamb cohorts on three Scottish sheep farms
Gastrointestinal nematodes (GIN) are a serious concern for sheep producers worldwide. However, there is a paucity of evidence describing the epidemiology of GIN on modern UK sheep farms. The aim of this paper was to understand whether expected seasonal variations of infection are still found in ewes and lambs under varying management strategies in temperate climates. Faecal egg counts (FEC) were conducted on freshly voided samples collected from groups of ewes and lambs every third week for twelve months on three farms in southeast Scotland. The patterns of egg output have been described here in relation to management practices undertaken on the farms. Despite changes in farming practice and climatic conditions, the findings complement historical studies detailing the epidemiology of GIN. Findings include a periparturient rise in ewe FEC on two of the farms, while lambing time treatment appeared to suppress this on the third farm. On the same two farms lamb FEC increased during the summer, reaching a peak in the autumn. The work also highlights how the ad hoc use of anthelmintics does little to impact these patterns
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
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
Real World Learning and Authentic Assessment
As students increasingly adopt a consumerist lifestyle academics are under pressure to assess and mark more students’ assignments in quicker turn around periods. In no other area is the marketisation shift between student and academic more apparent in the accountability that academics now need to demonstrate to students in their grading and feedback (Boud & Molloy, 2013). When evaluating their higher education experience students are most likely to complain about their grading or feedback (Boud & Molloy, 2013) and National Student Survey results consistently indicate that this category, more than any other, has the highest student dissatisfaction rates (Race, 2014)
Real World Learning: Simulation and Gaming
Simulations and games are being used across a variety of subject areas as a means to provide insight into real world situations within a classroom setting; they offer many of the benefits of real world learning but without some of the associated risks and costs. Lean, Moizer, Derham, Strachan and Bhuiyan aim to evaluate the role of simulations and games in real world learning. The nature of simulations and games is discussed with reference to a variety of examples in Higher Education. Their role in real world learning is evaluated with reference to the benefits and challenges of their use for teaching and learning in Higher Education. Three case studies from diverse subject contexts are reported to illustrate the use of simulations and games and some of the associated issues
A autoridade, o desejo e a alquimia da política: linguagem e poder na constituição do papado medieval (1060-1120)
МЕТОДИКА ВДОСКОНАЛЕННЯ ЕНЕРГО-ЕКОЛОГІЧНИХ ТА МІЦНІСНИХ ПОКАЗНИКІВ ТРАНСПОРТНОГО ДИЗЕЛЯ
The article deals with a complex method of deterioration of economic, ecological, and strength indicators of 16ЧН26/27 transport diesel engine. According to the offered method, there were considered conjugated problems applicable to the transport diesel engine combustion chamber and cooling cavities of the cylinder head. Based on the complex research conductedРозглянуто методику поліпшення економічних, екологічних та міцнісних показників транспортного дизеля 16ЧН26/27. Згідно із запропонованою методикою з використання чисельних методів розглядаються спряжені задачі для камери згоряння дизеля та порожнин охолодження головки циліндр
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