11,362 research outputs found
Robust automated servicing of passenger train fluids
To meet increased capacity demands of passengers in the rail industry, a robotic and autonomous system that services the fluids on passenger rail vehicles was proposed. A hierarchical task analysis of fluid servicing processes was conducted and human and system errors were highlighted. This information, along with opinions of technical managers and staff were inputted into a quality function deployment matrix to make a design specification; from this specification two concepts were proposed. Both concepts are viable but modification to rail vehicles is required. A proof of concept will next be developed to begin a path to a commercial product.Brunel University London would like to acknowledge RSSB and RRUKA for funding this project and providing contact with key rail stakeholders
First Principles Study of Structural, Electronic and Magnetic Interplay in Ferroelectromagnetic Yttrium Manganite
We present results of local spin density approximation pseudopotential
calculations for the ferroelectromagnet, yttrium manganite (YMnO3). The origin
of the differences between ferroelectric and non-ferroelectric perovskite
manganites is determined by comparing the calculated properties of yttrium
manganite in its ferroelectric hexagonal and non-ferroelectric orthorhombic
phases. In addition, orthorhombic YMnO3 is compared with the prototypical
non-ferroelectric manganite, lanthanum manganite. We show that, while the
octahedral crystal field splitting of the cubic perovskite structure causes a
centro-symmetric Jahn-Teller distortion around the Mn3+ ion, the markedly
different splitting in hexagonal perovskites creates an electronic
configuration consistent with ferroelectric distortion. We explain the nature
of the distortion, and show that a local magnetic moment on the Mn3+ ion is a
requirement for it to occur.Comment: Replacement of earlier version with error in pseudopotentia
Nutritional status of cancer patients in chemotherapy; dietary intake, nitrogen balance and screening
To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldOBJECTIVE: To evaluate a short screening sheet (SSM) for malnutrition and to investigate the nutritional status of patients receiving chemotherapy for cancer of the lungs, colon or breast at an outpatient clinic. DESIGN: Full nutritional assessment was conducted to define malnutrition and validate the SSM. Additionally, weight change from earlier healthy weight was evaluated, and calculations for intake of energy-giving nutrients (three-day-weighed food records) and protein balance were performed. After the evaluation study, the SSM was tested in clinical routine and data collected about patients' need for nutritional counseling. SUBJECTS: Patients at the outpatient clinic of the Department of Oncology at Landspitali-University Hospital (n=30 with lung-, colon- or breast cancer in the study population, n=93 with all cancer type in clinical routine screening). RESULTS: Malnutrition was defined by full nutritional assessment in 20% of the participating patients and SSM had high sensitivity and specificity. Declining nutritional status of the patients was seen as a negative nitrogen balance and unintentional weight loss from healthy weight, but not as total energy intake, recent weight loss or underweight. The test of SSM in clinical routine showed that 40% were malnourished. According to the patients, 80% needed nutritional counseling but only 17% had such counseling. CONCLUSION: Screening (SSM) for malnutrition in cancer patients is a valid simple approach to define cancer patients for nutritional care. More patients regard themselves in need for nutritional counseling than the number of patients really achieving any
Exploring the acceleration of the Met Office NERC Cloud model using FPGAs
The use of Field Programmable Gate Arrays (FPGAs) to accelerate computational
kernels has the potential to be of great benefit to scientific codes and the
HPC community in general. With the recent developments in FPGA programming
technology, the ability to port kernels is becoming far more accessible.
However, to gain reasonable performance from this technology it is not enough
to simple transfer a code onto the FPGA, instead the algorithm must be
rethought and recast in a data-flow style to suit the target architecture. In
this paper we describe the porting, via HLS, of one of the most computationally
intensive kernels of the Met Office NERC Cloud model (MONC), an atmospheric
model used by climate and weather researchers, onto an FPGA. We describe in
detail the steps taken to adapt the algorithm to make it suitable for the
architecture and the impact this has on kernel performance. Using a PCIe
mounted FPGA with on-board DRAM, we consider the integration on this kernel
within a larger infrastructure and explore the performance characteristics of
our approach in contrast to Intel CPUs that are popular in modern HPC machines,
over problem sizes involving very large grids. The result of this work is an
experience report detailing the challenges faced and lessons learnt in porting
this complex computational kernel to FPGAs, as well as exploring the role that
FPGAs can play and their fundamental limits in accelerating traditional HPC
workloads.Comment: Preprint of article in proceedings, ISC High Performance 2019.
Lecture Notes in Computer Science, vol 1188
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Understanding the direct and indirect mechanisms of xylanase action on starch digestion in broilers
The objective of the current study was to investigate the mechanisms of xylanase action in a maize-soya diet and its effect on starch digestion. A total of 60 broilers were divided into 6 treatment groups; a control group without xylanase, and five other groups supplemented with xylanase (Econase XT 25; 100 g/t) from 1, 2, 3, 4 or 5 weeks before slaughter. At the end of the experiment, digesta was collected from the gizzard, upper and lower small intestine, and both caeca. Digesta pH ranged from pH 2.2-4.4, 5.9-6.6, 6.7-7.8 and 5.7-7.3 in the gizzard, upper small intestine, lower small intestine, and both caeca, respectively, with no effect of xylanase (P > 0.05). Scanning Electron Microscope (SEM) images along with total starch measurements showed the progression of starch digestion through the tract. The SEM did not show any greater disruption to cell wall material with xylanase supplementation. This suggests that xylanase was not working directly on the cell wall and provides evidence for the hypothesis that xylanase works through an indirect mechanism. Peptide YY (PYY) concentration in the blood was higher during the first few weeks of supplementation, with longer periods of supplementation nulling this effect, implying that xylanase may be acting through a prebiotic mechanism. The RT-q PCR results revealed a numerical increase in glucose transporter (GLUT2 and SGLT1) expression at 2 and 3 weeks of xylanase supplementation, respectively, which might suggest a greater absorption capacity of birds. From these results, a potential mechanism of xylanase action in maize-based diets has been proposed
Room temperature plasmon laser by total internal reflection
Plasmon lasers create and sustain intense and coherent optical fields below
light's diffraction limit with the unique ability to drastically enhance
light-matter interactions bringing fundamentally new capabilities to
bio-sensing, data storage, photolithography and optical communications.
However, these important applications require room temperature operation, which
remains a major hurdle. Here, we report a room temperature semiconductor
plasmon laser with both strong cavity feedback and optical confinement to
1/20th of the wavelength. The strong feedback arises from total internal
reflection of surface plasmons, while the confinement enhances the spontaneous
emission rate by up to 20 times.Comment: 8 Page, 2 Figure
Krill faecal pellets drive hidden pulses of particulate organic carbon in the marginal ice zone
The biological carbon pump drives a flux of particulate organic carbon (POC) through the ocean and affects atmospheric levels of carbon dioxide. Short term, episodic flux events are hard to capture with current observational techniques and may thus be underrepresented in POC flux estimates. We model the potential hidden flux of POC originating from Antarctic krill, whose swarming behaviour could result in a major conduit of carbon to depth through their rapid exploitation of phytoplankton blooms and bulk egestion of rapidly sinking faecal pellets (FPs). Our model results suggest a seasonal krill FP export flux of 0.039 GT C across the Southern Ocean marginal ice zone, corresponding to 17–61% (mean 35%) of current satellite-derived export estimates for this zone. The magnitude of our conservatively estimated flux highlights the important role of large, swarming macrozooplankton in POC export and, the need to incorporate such processes more mechanistically to improve model projections
Probing the ultimate limits of plasmonic enhancement.
Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.Supported by Air
Force Office of Scientific Research grant FA9550-09-1-0562
and by the Army Research Office through Multidisciplinary
University Research Initiative grant W911NF-09-1-0539.
Also supported by the Leverhulme Trust and the Marie
Curie Actions (J.B.P., S.A.M., and A.I.F.-D.), NIH grant
R21EB009862 (A.C.), and NIH F32 award F32EB009299
(R.T.H.)
Projections of the healthcare costs and disease burden due to hepatitis C infection under different treatment policies in Malaysia, 2018-2040
The World Health Organisation (WHO) has set ambitious goals to reduce the global disease burden associated with, and eventually eliminate, viral hepatitis
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