4,850 research outputs found
Some potential blood flow experiments for space
Blood is a colloidal suspension of cells, predominantly erythrocytes, (red cells) in an aqueous solution called plasma. Because the red cells are more dense than the plasma, and because they tend to aggregate, erythrocyte sedimentation can be significant when the shear stresses in flowing blood are small. This behavior, coupled with equipment restrictions, has prevented certain definitive fluid mechanical studies from being performed with blood in ground-based experiments. Among such experiments, which could be satisfactorily performed in a microgravity environment, are the following: (1) studies of blood flow in small tubes, to obtain pressure-flow rate relationships, to determine if increased red cell aggregation can be an aid to blood circulation, and to determine vessel entrance lengths, and (2) studies of blood flow through vessel junctions (bifurcations), to obtain information on cell distribution in downstream vessels of (arterial) bifurcations, and to test flow models of stratified convergent blood flows downstream from (venous) bifurcations
Paradigm shift from student to researcher: An academic preparation program for international students
Although there are many Academic Preparation Programs designed for international postgraduate students, the importance of establishing “the role of the researcher” is rarely the focus of these programs. This role is a fundamental “threshold concept” (Meyer & Land, 2006) for postgraduate success which has the potential to be transformational at both Masters and PhD levels. This paper reports on an intensive academic preparation program (IAPP) for international postgraduate students commencing study at UNSW in 2009. This pilot program consisted of 40 hours facilitation prior to commencement of Semester 1, 2009. The program aimed to explore the “role of the researcher” by engaging in academic literacies fundamental to postgraduate expectations and empowering each student by acknowledging they were budding specialists in their disciplinary field. The design of the program encouraged personal responsibility for research and learning. This gave learners confidence to explore their reflective and critical learning process and to fine tune their research interests. Learning activities were designed to foster and record reflective practice. The use of a learning journal, group discussions and debriefings were central to the program and increased learners’ confidence as researchers. Student feedback of this pilot program was very positive and demonstrated its transformational nature. Based on this experience, we suggest that developing the “role of the researcher” offers another direction to consider when designing international preparation programs
Diatom analysis of three Norwegian cores
The purpose of this project is to supply diatom data to the Norwegian Institute of Water Research
for cores from three Norwegian lakes: Steinsfjorden, Lyseren and Gjersjøen. The data will feed into
a palaeolimnological project which also includes analysis of algal pigments and radiometric dating
of the cores.
The study aims to assess shifts in the diatom assemblages and to determine the nature of the
baseline assemblages. Additionally the project aims to apply an existing diatom-phosphorus (P)
transfer function to the diatom data in order to infer the trophic histories of the lakes
Magnetic Field Structure around Low-Mass Class 0 Protostars: B335, L1527 and IC348-SMM2
We report new 350 micron polarization observations of the thermal dust
emission from the cores surrounding the low-mass, Class 0 YSOs L1527,
IC348-SMM2 and B335. We have inferred magnetic field directions from these
observations, and have used them together with results in the literature to
determine whether magnetically regulated core-collapse and star-formation
models are consistent with the observations. These models predict a pseudo-disk
with its symmetry axis aligned with the core magnetic field. The models also
predict a magnetic field pinch structure on a scale less than or comparable to
the infall radii for these sources. In addition, if the core magnetic field
aligns (or nearly aligns) the core rotation axis with the magnetic field before
core collapse, then the models predict the alignment (or near alignment) of the
overall pinch field structure with the bipolar outflows in these sources. We
show that if one includes the distorting effects of bipolar outflows on
magnetic fields, then in general the observational results for L1527 and
IC348-SMM2 are consistent with these magnetically regulated models. We can say
the same for B335 only if we assume the distorting effects of the bipolar
outflow on the magnetic fields within the B335 core are much greater than for
L1527 and IC348-SMM2. We show that the energy densities of the outflows in all
three sources are large enough to distort the magnetic fields predicted by
magnetically regulated models.Comment: Accepted for publication in The Astrophysical Journa
A palaeolimnological study of Lake Vastadtjern, Norway
This project reports on analysis of a set of sediment cores collected from Lake Vastadtjern in
Norway in 2013-2014, spanning a total sediment depth of c. 600 cm. Multi-proxy
palaeoecological techniques, principally diatoms, macrofossils and Cladocera, were
employed to assess environmental change at the lake over the last c. 6000 years. The
project aims to determine ecological and chemical reference conditions of the lake to help
inform the setting of reference conditions for catchments dominated by clay-rich soils
Integrating Habitats Directive and Water Framework Directive Monitoring: Baseline Survey of Natura 2000 Standing Water Habitats in Wales
This report was commissioned by the Environment Agency (EA) on behalf of the
Countryside Council for Wales (CCW) in 2004. It brings together data collected in 2003
and 2004 from 28 Welsh lakes in 11 Special Areas of Conservation (SACs).
The report
• collates and presents limnological data collected for the Environment Agency in
2003 for the purposes of site condition assessment,
• presents limnological data collected for CCW in 2004 for the purposes of site
condition assessment,
• provides a series of lake data reports on each of the 11 specifies SACs.
Sampling and analytical methods are described and the data presented in the report
include;
• site information (catchment geology, land use and lake characteristics and
bathymetries),
• water chemistry, temperature and oxygen profiles,
• macrophyte survey data presented as DAFOR rated species lists,
• short core analysis for diatoms (required for 19 of the 28 sites)
Detection of a dense clump in a filament interacting with W51e2
In the framework of the Herschel/PRISMAS Guaranteed Time Key Program, the
line of sight to the distant ultracompact HII region W51e2 has been observed
using several selected molecular species. Most of the detected absorption
features are not associated with the background high-mass star-forming region
and probe the diffuse matter along the line of sight. We present here the
detection of an additional narrow absorption feature at ~70 km/s in the
observed spectra of HDO, NH3 and C3. The 70 km/s feature is not uniquely
identifiable with the dynamic components (the main cloud and the large-scale
foreground filament) so-far identified toward this region. The narrow
absorption feature is similar to the one found toward low-mass protostars,
which is characteristic of the presence of a cold external envelope. The
far-infrared spectroscopic data were combined with existing ground-based
observations of 12CO, 13CO, CCH, CN, and C3H2 to characterize the 70 km/s
component. Using a non-LTE analysis of multiple transitions of NH3 and CN, we
estimated the density (n(H2) (1-5)x10^5 cm^-3) and temperature (10-30 K) for
this narrow feature. We used a gas-grain warm-up based chemical model with
physical parameters derived from the NH3 data to explain the observed
abundances of the different chemical species. We propose that the 70 km/s
narrow feature arises in a dense and cold clump that probably is undergoing
collapse to form a low-mass protostar, formed on the trailing side of the
high-velocity filament, which is thought to be interacting with the W51 main
cloud. While the fortuitous coincidence of the dense clump along the line of
sight with the continuum-bright W51e2 compact HII region has contributed to its
non-detection in the continuum images, this same attribute makes it an
appropriate source for absorption studies and in particular for ice studies of
star-forming regions.Comment: Accepted for publication in A&
Desorption of CO and O2 interstellar ice analogs
Solid O2 has been proposed as a possible reservoir for oxygen in dense clouds
through freeze-out processes. The aim of this work is to characterize
quantitatively the physical processes that are involved in the desorption
kinetics of CO-O2 ices by interpreting laboratory temperature programmed
desorption (TPD) data. This information is used to simulate the behavior of
CO-O2 ices under astrophysical conditions. The TPD spectra have been recorded
under ultra high vacuum conditions for pure, layered and mixed morphologies for
different thicknesses, temperatures and mixing ratios. An empirical kinetic
model is used to interpret the results and to provide input parameters for
astrophysical models. Binding energies are determined for different ice
morphologies. Independent of the ice morphology, the desorption of O2 is found
to follow 0th-order kinetics. Binding energies and temperature-dependent
sticking probabilities for CO-CO, O2-O2 and CO-O2 are determined. O2 is
slightly less volatile than CO, with binding energies of 912+-15 versus 858+-15
K for pure ices. In mixed and layered ices, CO does not co-desorb with O2 but
its binding energies are slightly increased compared with pure ice whereas
those for O2 are slightly decreased. Lower limits to the sticking probabilities
of CO and O2 are 0.9 and 0.85, respectively, at temperatures below 20K. The
balance between accretion and desorption is studied for O2 and CO in
astrophysically relevant scenarios. Only minor differences are found between
the two species, i.e., both desorb between 16 and 18K in typical environments
around young stars. Thus, clouds with significant abundances of gaseous CO are
unlikely to have large amounts of solid O2.Comment: 8 pages + 2 pages online material, 8 figures (1 online), accepted by
A&
The treatment of nephrotic syndrome caused by primary (light chain) amyloid with vincristine, doxorubicin and dexamethasone.
Three out of four patients with primary (light chain) amyloid nephrotic syndrome treated with vincristine, doxorubicin and dexamethasone (VAD) induction obtained a partial response and are alive in continuing remission at 4.1, 6.5 and 9.3 years. These preliminary results are of considerable interest and suggest that prospective evaluation of this regimen is warranted in patients with this condition
Simulation for the oblique impact of a lattice system
The oblique collision between an elastic disk and an elastic wall is
numerically studied.
We investigate the dependency of the tangential coefficient of restitution on
the incident angle of impact.
From the results of simulation, our model reproduces experimental results and
can be explained by a phenomenological theory of the oblique impact.Comment: 30 pages, 9 figures, submitted to J. Phys. Soc. Japa
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