8,426 research outputs found
Gait Extraction and Description by Evidence-Gathering
Using gait as a biometric is of increasing interest, yet there are few model-based, parametric, approaches to extract and describe moving articulated objects. One new approach can detect moving parametric objects by evidence gathering, hence accruing known performance advantages in terms of performance and occlusion. Here we show how that the new technique can be extended not only to extract a moving person, but also to extract and concurrently provide a gait signature for use as a biometric. We show the natural relationship between the bases of these approaches, and the results they can provide. As such, these techniques allow for gait extraction and description for recognition purposes, and with known performance advantages of a well-established vision technique
Grassland Productivity and Water Quality: A 21st Century Issue
Irrigation and other changes to the hydrological cycle can increase soil and water salinity. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework. There is a lack of coherent interaction across discipline boundaries that links pollutant sources to impact. Grassland scientists need to work hand-in-hand with hydrologists and limnologists, to understand the water flows and the intricacies of ecological response, in stream or lake, in order to achieve a more coordinated and inclusive, holistic platform of research
Grassland Productivity and Water Quality: A 21\u3csup\u3est\u3c/sup\u3e Century Issue
Key points
1. Irrigation and other changes to the hydrological cycle can increase soil and water salinity.
2. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil.
3. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment.
4. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework.
5. There is a lack of coherent interaction across discipline boundaries that links pollutant sources to impact. Grassland scientists need to work hand-in-hand with hydrologists and limnologists, to understand the water flows and the intricacies of ecological response, in stream or lake, in order to achieve a more coordinated and inclusive, holistic platform of research
Repeated impact of simulated hail ice on glass fibre composite materials
Wind turbine blade damage, particularly leading edge erosion, is a significant problem faced by the renewable energy industry. Wind turbines are subject to a wide range of environmental factors during a 20 + year lifespan, with hailstones often touted as a key contributor to the deterioration of the blade profile. An experimental campaign was carried out to investigate the effects of repeated impact of smaller diameter simulated hail ice (SHI) on composite materials, to correspond to those most prevalent at wind farm locations. Hailstones of four different diameters (5 mm, 10 mm, 15 mm and 20 mm) were fired at velocities in the range of 50 ms −1 to 95 ms −1. Samples used for experimentation were manufactured from triaxial stitched glass fibre [0°/−45°/+45°] and epoxy resin. Damage was evaluated in terms of sample mass loss and microscopy of the composite surface. For all examples, mass loss was negligible and optical microscopy showed little evidence of surface damage. Surface degradation was discernible under scanning electron microscopy for the larger diameter SHI (≥15mm), with projectile velocity a notable factor in the extent of the damage. Even for large numbers of impacts, there was little noteworthy damage caused by smaller, more prevalent SHI (≤10mm). This suggests that hail is not a direct cause of wind turbine blade erosion
Manifestations of quantum holonomy in interferometry
Abelian and non-Abelian geometric phases, known as quantum holonomies, have
attracted considerable attention in the past. Here, we show that it is possible
to associate nonequivalent holonomies to discrete sequences of subspaces in a
Hilbert space. We consider two such holonomies that arise naturally in
interferometer settings. For sequences approximating smooth paths in the base
(Grassmann) manifold, these holonomies both approach the standard holonomy. In
the one-dimensional case the two types of holonomies are Abelian and coincide
with Pancharatnam's geometric phase factor. The theory is illustrated with a
model example of projective measurements involving angular momentum coherent
states.Comment: Some changes, journal reference adde
Design of top-hat purlins for cold-formed steel portal frames
This paper considers the use of cold-formed steel top-hat sections for purlins in the UK, as an alternative to conventional zed-sections. The use of such top-hat sections could be viable for cold-formed steel portal framing systems, where both the frame spacing and purlin span may be smaller than that of conventional hot-rolled steel portal frames. Furthermore, such sections are torsionally stiffer than zed-sections, and so have a greater resistance to lateral-torsional buckling. They also do not require the installation of anti-sag rods. The paper describes a combination of full-scale laboratory tests and non-linear elasto plastic finite element analyses. The results of twenty-seven tests on four different top-hat sections are presented. In terms of stiffness, good agreement between the experimental and finite element results is shown. The finite element model is then used for a parametric study to investigate the effect of different thicknesses and steel grades. Design recommendations are provided in the form of charts. The use of the finite element method in this way exploits modern computational techniques for an otherwise difficult structural design problem and reduces the need for an expensive and time consuming full laboratory study, whilst maintaining realistic and safe coverage of the important structural design issues
An Evaluation of the Possible Protective Effects of Neonatal Striatal Transplants Against Kainic Acid-Induced Lesions
The present study examined the recent report
that transplantation of neonatal striatal tissue
into kainic acid (KA) lesioned striatum protected
the contralateral striatum from a subsequent KA
lesion. We did not find a significant difference in
the survival rate of animals that received
neonatal striatal transplants into a KA lesioned
striatum followed by a subsequent lesion of the
contralateral striatum compared to those
animals that received bilateral KA-induced
striatal lesions alone. The tissue transplants did
not protect against the degeneration of striatal
neurons induced by KA. Indeed, the survival
rate was very low (25%) in the transplant groups.
A second experiment was also performed to
examine whether a neonatal striatal transplant
might reduce the severe syndrome of aphagia
and adipsia associated with KA lesions of the
striatum. Animals that received the neonatal
striatal transplants showed increased aphagia
and adipsia compared to animals only receiving
the KA lesion. Again, the transplant group had a
very low survival rate (10%). The present study
was unable to confirm that neonatal striatal
transplants protect against KA lesions either by
themselves or in conjunction with a recent KA
lesion
Conditional mutualism emerges from a largely antagonistic species network
O correcto estadiamento do cancro do pulmão é importante porque as opções terapêuticas e o prognóstico variam significativamente com o estadio da doença. Este, tal como é feito para outros tumores sólidos, baseia-se no sistema TNM.
A tomografia computorizada torácica é importante no estudo anatómico do tumor, da sua proximidade com estruturas locais e na invasão dos gânglios linfáticos hilares e mediastínicos. A tomografia por emissão de positrões fornece informação acerca da actividade funcional dos tecidos, tendo maiores sensibilidade e especificidade que a tomografia computorizada no estadiamento do mediastino. A avaliação clínica, que é composta pela história aprofundada e exame físico, continua a ser o melhor meio de predizer acerca de doença metastática. Se esta for negativa, estudos de imagem posteriores como a tomografia computorizada cerebral, cintigrama ósseo ou tomografia computorizada abdominal são desnecessários e a pesquisa de doença metastática está completa. Caso existam sinais ou sintomas de metastização, deverá ser iniciada uma sequência de exames de imagem, de acordo com aos dados obtidos na avaliação clínica.
Uma grande variedade de exames invasivos está disponível para o estadiamento do cancro do pulmão. Cada um deles tem especificidades técnicas e de acuidade diagnóstica que os tornam mais ou menos apropriados consoante a localização da lesão. Assim, a comparação directa entre estes testes invasivos não é possível e o problema é definir qual dos procedimentos é mais útil em cada situação.
O estadiamento molecular pode vir a ser um importante meio no estadiamento e estratificação prognóstica dos doentes com cancro do pulmão. No entanto ainda existem alguns problemas que têm limitado a aplicação deste conceito.The correctly staging of lung cancer is important because the treatment options and prognosis differ significantly with the stage of disease. This, as is done for other solid tumors, based on the TNM system. Chest TC imaging is important in the study of the anatomy of tumor, its proximity with local structures and the invasion of mediastinal and hilar lymph nodes. Positron emission tomography provides information about the functional activity of tissues with greater sensitivity and specificity than chest CT in the staging of the mediastinum. The clinical evaluation, which is made by thorough history and physical examination, remains the best way to predict about metastatic disease. If this is negative, further imaging studies such as CT scan of the head, bone scan or abdominal CT scan are unnecessary and the search for metastatic disease is complete. If there are signs or symptoms of metastasis, should be initiated a series of imaging tests, according to data obtained in the clinical evaluation.
A variety of invasive tests are available for the staging of lung cancer. Each of them has specific technical and diagnostic accuracy that makes them more or less appropriate depending on the location of the lesion. Thus, direct comparisons between these invasive tests are not possible and the problem is to define which procedures are most useful in each situation. Molecular staging may prove to be an important tool in the staging and prognostic stratification of patients with lung cancer. However, there are still some problems that have limited the application of the concept
Experimental and Analytical Studies of Cold-Formed Steel Sections with Edge-Stiffened Circular Holes Subjected to Web Crippling
Cold-formed steel sections are often used as wall studs or floor joists and such sections often include web holes for ease of installation of services. The holes are normally punched or bored and are unstiffened; when the holes are near to points of concentrated load, web crippling can be the critical design consideration. Recently, a new generation of cold-formed steel channel sections with edge-stiffened circular holes has been developed. The web holes are stiffened through a continuous edge stiffener/lip around the perimeter of the hole. In this paper, a combination of experimental investigations and non-linear finite element analyses are used to investigate the effect of such edge-stiffened holes under the interior-one-flange (IOF) and end-one-flange (EOF) loading conditions; for comparison, sections without holes and with unstiffened holes are also be considered. A non-linear finite element models are described, and the results compared against the laboratory test results; a good agreement was obtained in terms of both strength and failure modes
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