Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
Animal ; 17(5): 100786, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37075533

RESUMO

Animal welfare standards are used within the food industry to demonstrate efforts in reaching higher welfare on farms. To verify compliance with those standards, inspectors conduct regular on-farm animal welfare assessments. Conducting these welfare assessments can, however, be time-consuming and prone to human bias. The emergence of Digital Livestock Technologies (DLTs) offers new ways of monitoring farm animal welfare and can alleviate some of the challenges related to animal welfare assessments by collecting data automatically and more frequently. Whilst automating welfare assessments with DLTs may be promising, little attention has been paid to farmers' perceptions of the challenges that could prevent successful implementation. This study aims to address this gap by focusing on the trial of a DLT (a 3D machinelearning camera) to automate mobility and body condition scoring on 11 dairy cattle farms. Semi-structured, in-depth interviews were conducted with farmers, technology developers and a stakeholder involved in a farm assurance scheme (N14). Findings suggest that stakeholders perceived important benefits to the use of the camera in this context, from building consumer trust by increasing transparency to improved management efficiency. There was also a potential for greater consistency in data collection and thus for enhanced fairness across the UK dairy sector, particularly on the issue of lameness prevalence. However, stakeholders also raised important concerns, such as a lack of clarity around data ownership, reliability, and use, and the possibility of some farmers being penalised (e.g., if the technology failed to work). More clarity should thus be given to farmers in relation to data governance and evidence provided in terms of technical performance and accuracy. The findings of this study highlighted the need for more inclusive approaches to ensure farmers' concerns are adequately identified and addressed. These approaches can help minimise negative consequences to farmers and animal welfare, whilst maximising the potential benefits of automating welfare-related data collection.


Assuntos
Agricultura , Indústria de Laticínios , Bovinos , Animais , Humanos , Fazendas , Reprodutibilidade dos Testes , Animais Domésticos , Fazendeiros , Gado , Bem-Estar do Animal , Prevalência
2.
Phys Med Biol ; 63(8): 085015, 2018 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-29521280

RESUMO

As a prerequisite for clinical treatments it was necessary to characterize the Elekta 1.5 T MRI-linac 7 MV FFF radiation beam. Following acceptance testing, beam characterization data were acquired with Semiflex 3D (PTW 31021), microDiamond (PTW 60019), and Farmer-type (PTW 30013 and IBA FC65-G) detectors in an Elekta 3D scanning water phantom and a PTW 1D water phantom. EBT3 Gafchromic film and ion chamber measurements in a buildup cap were also used. Special consideration was given to scan offsets, detector effective points of measurement and avoiding air gaps. Machine performance has been verified and the system satisfied the relevant beam requirements of IEC60976. Beam data were acquired for field sizes between 1 × 1 and 57 × 22 cm2. New techniques were developed to measure percentage depth dose (PDD) curves including the electron return effect at beam exit, which exhibits an electron-type practical range of 1.2 ± 0.1 cm. The Lorentz force acting on the secondary charged particles creates an asymmetry in the crossline profiles with an average shift of +0.24 cm. For a 10 × 10 cm2 beam, scatter from the cryostat contributes 1% of the dose at isocentre. This affects the relative output factors, scatter factors and beam profiles, both in-field and out-of-field. The average 20%-80% penumbral width measured for small fields with a microDiamond detector at 10 cm depth is 0.50 cm. MRI-linac penumbral widths are very similar to that of the Elekta Agility linac MLC, as is the near-surface dose PDD(0.2 cm) = 57%. The entrance surface dose is ∼36% of Dmax. Cryostat transmission is quantified for inclusion within the treatment planning system. As a result, the 1.5 T MRI-linac 7 MV FFF beam has been characterised for the first time and is suitable for clinical use. This was a key step towards the first clinical treatments with the MRI-linac, which were delivered at University Medical Center Utrecht in May 2017 (Raaymakers et al 2017 Phys. Med. Biol. 62 L41-50).


Assuntos
Imageamento por Ressonância Magnética/métodos , Aceleradores de Partículas , Imagens de Fantasmas , Radiometria/métodos , Elétrons , Humanos , Campos Magnéticos , Posicionamento do Paciente , Água
3.
Phys Rev Lett ; 98(11): 113002, 2007 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-17501048

RESUMO

Antiprotons (p[over]) remain confined in a Penning trap, in sufficient numbers to form antihydrogen (H[over ) atoms via charge exchange, when the radial field of a quadrupole Ioffe trap is added. This first demonstration with p[over] suggests that quadrupole Ioffe traps can be superimposed upon p[over] and e(+) traps to attempt the capture of H[over] atoms as they form, contrary to conclusions of previous analyses.

4.
Psychol Res ; 63(1): 70-82, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10743388

RESUMO

Human movement performance is subject to many physical and psychological constraints. Analyses of these constraints may not only improve our understanding of the performance aspects that subjects need to keep under continuous control, but may also shed light on the possible origins of specific behavioral preferences that people display in motor tasks. The goal of the present paper is to make an empirical contribution here. In a recent simulation study, we reported effects of pen-grip and forearm-posture constraints on the spatial characteristics of the pen tip's workspace in drawing. The effects concerned changes in the location, size, and orientation of the reachable part of the writing plane, as well as variations in the computed degree of comfort in the hand and finger postures required to reach the various parts of this area. The present study is aimed at empirically evaluating to what extent these effects influence subjects' graphic behavior in a simple, free line-drawing task. The task involved the production of small back-and-forth drawing movements in various directions, to be chosen randomly under three forearm-posture and five pen-grip conditions. The observed variations in the subjects' choice of starting positions showed a high level of agreement with those of the simulated graphic-area locations, showing that biomechanically defined comfort of starting postures is indeed a determinant of the selection of starting points. Furthermore, between-condition rotations in the frequency distributions of the realized stroke directions corresponded to the simulation results, which again confirms the importance of comfort in directional preferences. It is concluded that postural rather than spatial constraints primarily affect subjects' preferences for starting positions and stroke directions in graphic motor performance. The relevance of the present modelling approach and its results for the broader field of complex motor behavior, including the manipulation of tools, is indicated briefly.


Assuntos
Simulação por Computador , Cinestesia , Orientação , Desempenho Psicomotor , Adulto , Gráficos por Computador , Feminino , Antebraço , Lateralidade Funcional , Humanos , Masculino
5.
Acta Psychol (Amst) ; 100(1-2): 97-115, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9844559

RESUMO

Computer simulations aimed at assessing functional characteristics of the graphic workspace are presented. The simulations involve a 10-df kinematic model of the distal part of the writing arm, and yield the effective workspace of the pen tip under two types of kinematic constraints. The first constraint involves fixing the forearm under various pronation angles, the second governs the protrusion of the pen tip from the finger tips. The effective workspace is analyzed in terms of the effort required to reach the various locations in it, where effort is defined in terms of the joint angles adopted by the wrist and fingers to reach each location. The simulation results show agreements between the distribution of required effort over the workspace and known stroke-direction preferences in drawing. Furthermore, they predict shifts in the biases that are thought to lead to these preferences as a function of both hand pronation and pen protrusion.


Assuntos
Fenômenos Biomecânicos , Gráficos por Computador , Simulação por Computador , Articulações dos Dedos/fisiologia , Escrita Manual , Articulação do Punho/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Orientação/fisiologia , Pronação/fisiologia , Robótica
6.
J Mot Behav ; 28(3): 241-254, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12529207

RESUMO

Coordination of limb segments in graphic motor behavior has been studied primarily in cyclic tasks. In the present study, limb segment recruitment patterns were investigated in a discrete line-drawing task. Subjects (N = 11) performed pointing movements varying in direction, amplitude, and speed. The contributions of index finger, hand, and arm to the movement were analyzed by evaluating the angular displacements in 7 joint dimensions. The results showed that amplitude and direction affected limb segment involvement in the same way they have been reported to affect it in cyclic movements. Upward left- (up-left) directed movements were primarily achieved by fingers and arm, whereas upward right- (up-right) directed movements were accomplished with the hand and the arm. Large amplitudes elicited not only an increase of proximal but also a decrease of distal limb segment involvement, especially in the up-left direction. In the present discrete pointing task, effects of speed on limb segment involvement were different from speed effects that were observed earlier in cyclic tasks: Larger limb segments became more involved in fast than in slow discrete movements. With respect to the timing of limb segment recruitment, all joints tended to move simultaneously, but small deviations from synchronous joint movement onset and offset were present. The results are discussed in the context of recent theories of limb segment coordination.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA