959 resultados para vein occlusion


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The femoral region ('groin') appears to be increasingly commonly used by injecting drug users in the UK. With the advent of Britain's first supervised prescribed injectable opioid treatment clinic, unprecedented decisions and judgements were required about the safe supervision of this practice, or whether to permit this behaviour on site at all. This paper reports the reasons for, and outcome of, development of a clinical policy on injecting into the deep femoral vein (groin injecting)

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Stress responses are thought to act within the hypothalamopituitary unit to impair the reproductive system, and the sites of action may differ between sexes. The effect of isolation and restraint stress on pituitary responsiveness to GnRH in sheep was investigated, with emphasis on possible sex differences. Experiments were conducted during the breeding season and the nonbreeding season. In both experiments, 125 ng of GnRH was injected i.v. every 2 h into hypothalamopituitary disconnected, gonadectomized rams and ewes on 3 experimental days, with each day divided into two periods. During the second period on Day 2, isolation and restraint stress was imposed for 5.5 h. Plasma concentrations of LH and cortisol were measured in samples of blood collected from the jugular vein. In the second experiment (nonbreeding season), plasma concentrations of epinephrine, norepinephrine, 3,4-dihydroxyphenylalanine, and 3,4-dihydroxyphenylglycol were also measured. In both experiments, there was no effect of isolation and restraint stress on plasma concentrations of cortisol in either sex. During the breeding season, there was no effect of isolation and restraint stress on plasma concentrations of LH in either sex. During the nonbreeding season, the amplitude of the first LH pulse after the commencement of stress was significantly reduced (P < 0.05) in rams and ewes. In the second experiment, during stress there was a significant increase (P < 0.05) in plasma concentrations of epinephrine in rams and ewes and significantly higher (P < 0.05) basal concentrations of norepinephrine in ewes than in rams. These results suggest that in sheep stress reduces responsiveness of the pituitary gland to exogenous GnRH during the nonbreeding season but not during the breeding season, possibly because of mediators of the stress response other than those of the hypothalamus-pituitary-adrenal gland axis.

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The direction and speed of motion of a one-dimensional (1-D) stimulus, such as a grating, presented within a circular aperture is ambiguous. This ambiguity, referred to as the Aperture Problem (Fennema & Thompson, 1979) results from (i) the inability to detect motion parallel to grating orientation, and (ii) the occlusion of border information, such as the ‘ends’ of the grating, by the surface forming the aperture, Adelson and Movshon's (1982) intcrsection-of-constraints (IOC) model of motion perception describes a two-stage method of disambiguating the motion of 1-D moving stimuli (e.g., gratings) to produce unambiguous motion of two-dimensional (2-D) objects (e.g., plaid patterns) made up of several 1-D components. Specifically, in the IOC model ambiguous 1-D motions extracted by Stage 1 component-selective mechanisms are integrated by Stage 2 pattern-selective mechanisms to produce unambiguous 2-D motion signals. ‘Integration’ in the context of the IOC model involves determining the single motion vector (i.e., combination of direction and speed) which is consistent with the I-D components of a 2-D object. Since the IOC model assumes that 2-D objects undergo pure translation (i.e., without distortion, rotation, etc.), the motion vector consistent with all 1-D components describes the motion of the 2-D object itself. Adelson and Movshon (1982) propose that neural implementation of the computation underlying the IOC model is reflected in the perception of coherent 2-D plaid motion reported when two separately-moving ‘component’ gratings are superimposed. Using these plaid patterns the present thesis assesses the IOC model in terms of its ability to account for the perception of 2-D motion in a variety of circumstances. In the first series of experiments it is argued that the unambiguous motion perceived for a single grating presented within a rectangular aperture (i.e., the Barberpole illusion; Wallach, 1976) reflects application of the IOC computation to the moving 1-D grating and the stationary boundary of the aperture. While contrary to the assumption which underlies the IOC model (viz., that integration occurs between moving 1-D stimuli), evidence consistent with the involvement of the IOC computation in mediating the Barberpole illusion (in which there is only one moving stimulus) is obtained by measuring plaid coherence as a function of aperture shape. It is found that rectangular apertures which bias perceived component motions in directions consistent with plaid direction facilitate plaid coherence, while rectangular apertures which bias perceived component motions in directions inconsistent with plaid direction disrupt plaid coherence. In the second series of experiments, perceived directions of motion of type I symmetrical, type I asymmetrical, and type II plaids are measured with the aim of investigating the deviations in plaid directions reported by Ferrera and Wilson (1990) and Yo and Wilson (1992). Perceived directions of both asymmetrical and type II plaids are shown to deviate away from lOC-predicted directions and towards mean component direction. Furthermore, the magnitude of these deviations is being proportional to the difference between lOC-predicted plaid direction and mean component direction. On the basis of these directional deviations, modification to the IOC model is proposed. In the modified IOC model it is argued that plaid perception involves (i) the activity of Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these pattern-selective mechanisms) involved in implementing the IOC computation, and (ii) component-selective mechanisms which influence plaid perception directly, and ‘extraneously’ to the IOC computation. In the third series of experiments the validity of this modified IOC model, as well as the validity of alternative one-stage models of plaid perception are assessed in relation to perceived directions of plaid-induced MAEs as a function of both plaid direction and mean component direction. It is found that plaid-induced MAEs are shifted away from directions opposite to lOC-predicted plaid direction towards the direction opposite to mean component direction. This pattern of results is taken to be consistent with the modified IOC model which predicts the activity, and adaptation both of mechanisms signalling plaid direction (via implementation of the IOC computation), and ‘extraneous-type’ component-selective mechanisms signalling component directions. Alternative one-stage models which predict the adaptation of only mechanisms signalling plaid direction (the feature-tracking model), or the adaptation only of mechanisms signalling component directions (the distribution-of-activity model), cannot account for the directions of plaid-induced MAEs reported. The ability of the modified IOC model to account for the perceived directions of (i) gratings in rectangular apertures, (ii) various types of plaid in circular apertures, and (iii) directions of plaid-induced MAEs, is interpreted as supporting the proposition that human motion perception is based on a parallel and distributed process involving Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these mechanisms) taken to implement the IOC computation, and component-selective mechanisms taken to provide an 'extraneous' direct contribution to motion perception.

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A multi-resolution technique for matching a stereo pair of images based on translation invariant discrete multi-wavelet transform is presented. The technique uses the well known coarse to fine strategy, involving the calculation of matching points at the coarsest level with consequent refinement up to the finest level. Vector coefficients of the wavelet transform modulus are used as matching features, where modulus maxima defines the shift invariant high-level features (multiscale edges) with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps. Illuminative variation that can exist between the perspective views of the same scene is controlled using scale normalization at each decomposition level by dividing the details space coefficients with approximation space and then using normalized correlation. The problem of ambiguity, explicitly, and occlusion, implicitly, is addressed by using a geometric topological refinement procedure and symbolic tagging.

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Purpose – The constructs of relativism and absolutism have a significant role to play in the development of ethical theory; however, they are commonly simplified in their depictions and are philosophically more complex than we give them credit for. The purpose of this paper is to undertake an in-depth examination of ethical relativity and ethical absolutism before concluding with a discussion of which research implications warrant further investigation.
Design/methodology/approach – A descriptive, historical, anthological approach has been taken.
Findings – Ethical relativism is regrettably subject to a proliferation of related terminology and, in many instances with different meanings ascribed to similar terms. In addition, ethical relativity appears to attract different research perspectives that are heavily dependent on their academic origins. A clear distinction needs to be made between ethical and situational relativity. It is suggested that relativism is present in the process of moral justification and that ethical relativism should be analyzed from three levels: the individual level, the role and group level, and the cultural levels. The over-riding objection to ethical relativism rests on the consequences of accepting relativism, which undermines the existence and strength of global moral standards and the inherent positioning of ethical absolutism. Absolutism does not deny the existence of multiple moral practices evident around the world, but proposes that variations in ethical actions could still be rooted in common universal moral standards based on our requirements as human beings and the necessities of long-term survival.
Research limitations/implications – The ensuing discussions of relativism and absolutism open up a rich vein of research opportunities and suggest caution is required in regard to research methodologies. From a methodological perspective, care needs to be taken. For example, using hypothetical ethical dilemmas that are often unrelated to a specific industry or cultural setting has resulted in many researchers observing situational relativity rather than true ethical relativity.
Originality/value – This paper specifically examines whether there are differences in underlying and basic moral standards even though similarities in ethical behaviour have been determined, or whether differing ethical actions could, as the absolutists believe, originate from common universal standards despite apparent differences in perceptions and actions across cultures.

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The purpose of this study was to compare accumulated oxygen deficits and markers of anaerobic metabolism [plasma ammonia (NH3) and lactate (La) concentrations] in anaerobically trained male [n = 8, age 14.8 (0.5) years; maximal oxygen consumption V˙O2 max 61.74 (2.23) ml ·  kg−1 · min−1] and female [n = 8, age 14.5 (0.2) years; O2 max 49.62 (3.52) ml · kg−1 · min−1] adolescents. The exercise protocol consisted of runs to exhaustion at speeds predicted to represent 120% and 130% of O2 max. Arterialised blood samples were obtained from a pre-warmed hand via a catheter inserted into a forearm vein. Samples were taken at rest and after 1, 3, 5, 7, 10, 15 and 20 min of recovery. The high-intensity exercise resulted in mean accumulated oxygen deficits that were less (P < 0.05) in females (52.3 ml · kg−1) than in males (68.6 ml · kg−1). Lower (P < 0.05) plasma concentrations of NH3 and La−1, and a higher pH were evident in females compared with males during various stages of the 20-min recovery period. The increase in anaerobic performance in the male adolescent athletes when compared with their female counterparts was associated with an increased plasma concentration of selected plasma and blood metabolites. The observed results may reflect well-established differences between the sexes in the morphology and metabolic power of muscle.

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This study examined forearm blood flow (FBF) in individuals with chronic heart failure (CHF) at rest, moderate exercise, and following limb occlusion. FBF was measured by venous occlusion plethysmography in CHF patients (n = 43) and healthy age-matched volunteers (n = 8) at rest and during exercise consisting of intermittent isometric hand squeezing at 15, 30, and 45% of maximum voluntary contraction (MVC). Peak vasodilatory capacity was also determined following the release of an occluding arm cuff. FBF was lower in CHF patients during exercise and during peak reactive hyperemia (PRH) compared to healthy volunteers, but there was no significant difference between groups at rest. Peak vasodilatory capacity was significantly higher in healthy volunteers than the CHF group ((30.6 ± 8.6 ml±100 mL-1±min-1 and 18.3 ± 6.9 ml±100 mL-1±min-1, respectively). Local blood flow stimulation in response to exercise or limb occlusion is reduced in individuals with CHF, however, there was no difference in resting flows between the two groups, suggesting vasodilatory medication may restore resting blood flow to healthy values.

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This series of photographs focuses on caves in Western Victoria that have a layer of colonial occupation; caves said to be inhabited by bush rangers, escaped convicts, shipwreck survivors and hermits. The photographer was drawn to a rich vein of sites associated with colonial myths of inhabitation. These include the escaped convict William Buckley; Miss Carmichael, survivor of the wreck of the Lochard in 1878; Bushranger Captain Melville, and elusive enigmatic Black Ranges hermit David Ross. The resulting photographs explore the sensory and psychological resonance of these extraordinary places, what they feel like and how they feed the imagination, the need to feel rooted, to feel at home. Her approach embraces the paradoxical ambivalence of this need and the complex process of negotiating our presence in the land.

    The Cavity photographic series included the following photographs:
  • - Melville Caves
  • - Wildman Cave (East)
  • - Miss Carmichael's Cave (Longview)
  • - Buckley's Cave
  • - Miss Carmichael's Cave
  • - Wildman Cave
  • - Sister Rocks


  • And the following stop motion animation:
  • - Miss Carmichael's View
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Automatic human action recognition has been a challenging issue in the field of machine vision. Some high-level features such as SIFT, although with promising performance for action recognition, are computationally complex to some extent. To deal with this problem, we construct the features based on the Distance Transform of body contours, which is relatively simple and computationally efficient, to represent human action in the video. After extracting the features from videos, we adopt the Conditional Random Field for modeling the temporal action sequences. The proposed method is tested with an available standard dataset. We also testify the robustness of our method on various realistic conditions, such as body occlusion or intersection.

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We present a distributed surveillance system that uses multiple cheap static cameras to track multiple people in indoor environments. The system has a set of Camera Processing Modules and a Central Module to coordinate the tracking tasks among the cameras. Since each object in the scene can be tracked by a number of cameras, the problem is how to choose the most appropriate camera for each object. This is important given the need to deal with limited resources (CPU, power etc.). We propose a novel algorithm to allocate objects to cameras using the object-to-camera distance while taking into account occlusion. The algorithm attempts to assign objects in the overlapping field of views to the nearest camera, which can see the object without occlusion. Experimental results show that the system can coordinate cameras to track people and can deal well with occlusion.

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This paper focuses on the problem of tracking people through occlusions by scene objects. Rather than relying on models of the scene to predict when occlusions will occur as other researchers have done, this paper proposes a linear dynamic system that switches between two alternatives of the position measurement in order to handle occlusions as they occur. The filter automatically switches between a foot-based measure of position (assuming z = Q) to a head-based position measure (given the person's height) when an occlusion of the person's lower body occurs. No knowledge of the scene or its occluding objects is used. Unlike similar research [2, 14], the approach does not assume a fixed height for people and so is able to track humans through occlusions even when they change height during the occlusion. The approach is evaluated on three furnished scenes containing tables, chairs, desks and partitions. Occlusions range from occlusions of legs, occlusions whilst being seated and near-total occlusions where only the person's head is visible. Results show that the approach provides a significant reduction in false-positive tracks in a multi-camera environment, and more than halves the number of lost tracks in single monocular camera views.

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The filling of printed forms has always been an issue for the visually impaired. Though optical character recognition technology has helped many blind people to ‘read’ the world, there is not a single device that allows them to fill out a paper-based form without a human assistant. The task of filling forms is however an essential part of their daily lives, for example, for access to social security or benefits. This paper describes a solution that allows a blind person to complete paper-based forms, pervasively and independently, using only off-the-shelf equipment including a Smartphone, a clipboard with sliding ruler, and a ballpoint pen. A dynamic color fiduciary (point of reference) marker is designed so that it can be moved by the user to any part of the form such that all regions can be “visited”. This dynamic color fiduciary marker is robust to camera focus and partial occlusion, allowing flexibility in handling the Smartphone with embedded camera. Feedback is given to the blind user via both voice and tone to facilitate efficient guidance in filling out the form. Experimental results have shown that this prototype can help visually impaired people to fill out a form independently.

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In this paper, we present a distributed surveillance system that uses multiple cheap static cameras to track multiple people in indoor environments. The system has a set of Camera Processing Modules and a Central Module to coordinate the tracking tasks among the cameras. Since each object in the scene can be tracked by a number of cameras, the problem is how to choose the most appropriate camera for each object. We propose a novel algorithm to allocate objects to cameras using the object-to-camera distance while taking into account occlusion. The algorithm attempts to assign objects in the overlapping fields of view to the nearest camera which can see the object without occlusion. Experimental results show that the system can coordinate cameras to track people properly and can deal well with occlusion.

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Introduction
In January 2006, the Renal Dialysis Unit at Geelong Hospital appointed a Vascular Access Nurse. A Transonic Flow Qc HDO2 Ultrasound Dilution Monitor was purchased to monitor access flow and recirculation in arteriovenous fistulae in an attempt to predict AVF stenoses requiring early surgical correction.

Methods
A bi-monthly monitoring program tested all facility-based patients. 82 patients were assessed for access flow and recirculation between February and December 2006.

Results
18 (22%) had poor AVF function; 13 with access flows <500ml/minute on initial testing and 5 with an access flow decreasing >25% over a four month period. Of the 18 patients shown to have poor access flow, 2 died within one month of measurement while 5 were too frail to attempt corrective surgery. The remaining 11 proceeded to ultrasound or fistulography. A >50% stenosis was detected in all 11 cases. Of these, 4 had successful vein patch surgery and one had PTFE grafting, each with marked improvement in access flow. One had failed vein patch surgery requiring creation of a femoral AVF, one patient required cvc insertion to await AVF creation, and one had failed stenting requiring a permanent cvc. 3 died before planned surgery.

Conclusion
5 of the 82 patients that had access flow assessment, and needed further evaluation, proceeded to successful pre-emptive surgical intervention. We believe the Transonic is a useful adjunct to routine clinical AVF surveillance, in providing early evidence of AVF failure that can be avoided by pre-emptive surgery.