| 1. |
- Arakelian, Erebouni, 1973-
(författare)
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Operating Room Efficiency and Postoperative Recovery after Major Abdominal Surgery : The Surgical Team’s Efficiency and the Early Postoperative Recovery of Patients with Peritoneal Carcinomatosis
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In selected patients, surgical treatments such as cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have enabled curative treatment options for previously incurable diseases, such as peritoneal carcinomatosis (PC). The introduction of resource demanding surgery could affect the work process, efficiency, and productivity within a surgical department and factors influencing patient postoperative recovery processes may have an impact on the efficiency of patient care after major surgery.The aim of this thesis was to investigate operating room efficiency from the perspective of both staff and leaders’ in two different settings (Papers I and II) and the early postoperative recovery of patients with peritoneal carcinomatosis (Papers III and IV).Interviews were held with 21 people in a county hospital and 11 members of the PC team in a university hospital, and a phenomenographic approach was used to analysis the data (Papers I and II). The patients’ postoperative recovery and pulmonary adverse events (AE) were determined from data retrieved from the electronic health records of 76 patients (Papers III and IV).The concept of efficiency was understood in different ways by staff members and their leaders (Paper I). However, when working in a team, the team members had both organisation-oriented and individual-oriented understanding of efficiency at work that focused on the patients and the quality of care (Paper II).The patients with PC regained gastrointestinal functions and could be mobilised during early postoperative recovery phase, although many patients suffered from psychological disturbances, sleep deprivation, and nausea (Paper III). Postoperative clinical and radiological pulmonary AE were common, but did not affect the early recovery process (Paper IV).In conclusion, leaders who are aware of the variation in understanding the concept of efficiency are better able to create the same platform for staff members by defining the concept of efficiency within the organisation. In a team organisation, the team members have a wider understanding of the concept of efficiency with more focus on the patients. The factors affecting postoperative recovery and pulmonary AE should be considered when designing individualised patient care plans in order to attain a more efficient recovery.
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| 2. |
- Barnett, Paul D, et al.
(författare)
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Motion adaptation and the velocity coding of natural scenes
- 2010
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 20:11, s. 994-999
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Tidskriftsartikel (refereegranskat)abstract
- Estimating relative velocity in the natural environment is challenging because natural scenes vary greatly in contrast and spatial structure. Widely accepted correlation-based models for elementary motion detectors (EMDs) are sensitive to contrast and spatial structure and consequently generate ambiguous estimates of velocity [1]. Identified neurons in the third optic lobe of the hoverfly can reliably encode the velocity of natural images largely independent of contrast [2], despite receiving inputs directly from arrays of such EMDs [3, 4]. This contrast invariance suggests an important role for additional neural processes in robust encoding of image motion [2, 5, 6]. However, it remains unclear which neural processes are contributing to contrast invariance. By recording from horizontal system neurons in the hoverfly lobula, we show two activity-dependent adaptation mechanisms acting as near-ideal normalizers for images of different contrasts that would otherwise produce highly variable response magnitudes. Responses to images that are initially weak neural drivers are boosted over several hundred milliseconds. Responses to images that are initially strong neural drivers are reduced over longer time scales. These adaptation mechanisms appear to be matched to higher-order natural image statistics reconciling the neurons' accurate encoding of image velocity with the inherent ambiguity of correlation-based motion detectors.
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| 3. |
- Barnett, Paul, et al.
(författare)
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Retinotopic organization of small-field-target-detecting neurons in the insect visual system.
- 2007
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 17:7, s. 569-578
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDespite having tiny brains and relatively low-resolution compound eyes, many fly species frequently engage in precisely controlled aerobatic pursuits of conspecifics. Recent investigations into high-order processing in the fly visual system have revealed a class of neurons, coined small-target-motion detectors (STMDs), capable of responding robustly to target motion against the motion of background clutter. Despite limited spatial acuity in the insect eye, these neurons display exquisite sensitivity to small targets. ResultsWe recorded intracellularly from morphologically identified columnar neurons in the lobula complex of the hoverfly Eristalis tenax. We show that these columnar neurons with exquisitely small receptive fields, like their large-field counterparts recently described from both male and female flies, have an extreme selectivity for the motion of small targets. In doing so, we provide the first physiological characterization of small-field neurons in female flies. These retinotopically organized columnar neurons include both direction-selective and nondirection-selective classes covering a large area of visual space. ConclusionsThe retinotopic arrangement of lobula columnar neurons sensitive to the motion of small targets makes a strong case for these neurons as important precursors in the local processing of target motion. Furthermore, the continued response of STMDs with such small receptive fields to the motion of small targets in the presence of moving background clutter places further constraints on the potential mechanisms underlying their small-target tuning.
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| 4. |
- Bolzon, Douglas M, et al.
(författare)
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Local and large-range inhibition in feature detection
- 2009
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 29:45, s. 14143-14150
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Tidskriftsartikel (refereegranskat)abstract
- Lateral inhibition is perhaps the most ubiquitous of neuronal mechanisms, having been demonstrated in early stages of processing in many different sensory pathways of both mammals and invertebrates. Recent work challenges the long-standing view that assumes that similar mechanisms operate to tune neuronal responses to higher order properties. Scant evidence for lateral inhibition exists beyond the level of the most peripheral stages of visual processing, leading to suggestions that many features of the tuning of higher order visual neurons can be accounted for by the receptive field and other intrinsic coding properties of visual neurons. Using insect target neurons as a model, we present unequivocal evidence that feature tuning is shaped not by intrinsic properties but by potent spatial lateral inhibition operating well beyond the first stages of visual processing. In addition, we present evidence for a second form of higher-order spatial inhibition--a long-range interocular transfer of information that we argue serves a role in establishing interocular rivalry and thus potentially a neural substrate for directing attention to single targets in the presence of distracters. In so doing, we demonstrate not just one, but two levels of spatial inhibition acting beyond the level of peripheral processing.
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| 5. |
- Brinkworth, Russel, et al.
(författare)
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First year expectations and experiences : Student and teacher perspectives
- 2009
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Ingår i: Higher Education. - : Springer Science and Business Media LLC. - 0018-1560 .- 1573-174X. ; 58:2, s. 157-173
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Tidskriftsartikel (refereegranskat)abstract
- Transitioning from high-school to university can be difficult, and many university teachers feel students are often ill-prepared for the change. To investigate this 233 Humanities and Science students at the University of Adelaide were surveyed 6 months into their first year regarding experiences of teaching and learning at university. 189 students were also surveyed 18 months after commencement, to gain retrospective views of their transition year, as were lecturers and tutors of both groups. Results were compared to similar Orientation Week questionnaires that focused on expectations. Questions included reasons for selecting degrees, quality of teacher feedback and perceived impact of outside commitments. Even though student expectations, student experience, and teacher views differed, remarkable similarities emerged across the two degree programs (Science and Humanities). Our findings thus highlight a call for non-specialised transition programs to meet the needs of first year students and facilitate the transition from secondary to tertiary education.
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| 6. |
- Daňková, Klára, et al.
(författare)
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Temperature during pupal development affects hoverfly developmental time, adult life span, and wing length
- 2023
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Hoverflies (Diptera, Syrphidae) are cosmopolitan, generalist flower visitors and among the most important pollinators after bees and bumblebees. The dronefly Eristalis tenax can be found in temperate and continental climates across the globe, often synanthropically. Eristalis tenax pupae of different generations and different climate zones are thus exposed to vastly different temperatures. In many insects, the ambient temperature during the pupal stage affects development, adult size, and survival; however, the effect of developmental temperature on these traits in hoverflies is comparatively poorly understood. We here reared E. tenax pupae at different temperatures, from 10°C to 25°C, and quantified the effect on adult hoverflies. We found that pupal rearing at 17°C appeared to be optimal, with high eclosion rates, longer wings, and increased adult longevity. Rearing temperatures above or below this optimum led to decreased eclosion rates, wing size, and adult survival. Similar thermal dependence has been observed in other insects. We found that rearing temperature had no significant effect on locomotor activity, coloration or weight, despite evidence of strong sexual dimorphism for each of these traits. Our findings are important as hoverflies are key pollinators, and understanding the effects of developmental temperature could potentially be useful for horticulture.
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| 7. |
- Dyakova, Olga, et al.
(författare)
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Acute sleep loss induces signs of visual discomfort in young men
- 2019
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Ingår i: Journal of Sleep Research. - : Wiley. - 0962-1105 .- 1365-2869. ; 28:6
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Tidskriftsartikel (refereegranskat)abstract
- Acute sleep loss influences visual processes in humans, such as recognizing facial emotions. However, to the best of our knowledge, no study till date has examined whether acute sleep loss alters visual comfort when looking at images. One image statistic that can be used to investigate the level of visual comfort experienced under visual encoding is the slope of the amplitude spectrum, also referred to as the slope constant. The slope constant describes the spatial distribution of pixel intensities and deviations from the natural slope constant can induce visual discomfort. In the present counterbalanced crossover design study, 11 young men with normal or corrected-to-normal vision participated in two experimental conditions: one night of sleep loss and one night of sleep. In the morning after each intervention, subjects performed a computerized psychophysics task. Specifically, they were required to adjust the slope constant of images depicting natural landscapes and close-ups with a randomly chosen initial slope constant until they perceived each image as most natural looking. Subjects also rated the pleasantness of each selected image. Our analysis showed that following sleep loss, higher slope constants were perceived as most natural looking when viewing images of natural landscapes. Images with a higher slope constant are generally perceived as blurrier. The selected images were also rated as less pleasant after sleep loss. No such differences between the experimental conditions were noted for images of close-ups. The results suggest that sleep loss induces signs of visual discomfort in young men. Possible implications of these findings are discussed.
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| 8. |
- Dyakova, Olga, et al.
(författare)
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Image statistics and their processing in insect vision
- 2017
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Ingår i: Current Opinion in Insect Science. - : Elsevier BV. - 2214-5745 .- 2214-5753. ; 24, s. 7-14
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Forskningsöversikt (refereegranskat)abstract
- Natural scenes may appear random, but are not only constrained in space and time, but also show strong spatial and temporal correlations. Spatial constraints and correlations can be described by quantifying image statistics, which include intuitive measures such as contrast, color and luminance, but also parameters that need some type of transformation of the image. In this review we will discuss some common tools used to quantify spatial and temporal parameters of naturalistic visual input, and how these tools have been used to inform us about visual processing in insects. In particular, we will review findings that would not have been possible using conventional, experimenter defined stimuli.
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| 9. |
- Dyakova, Olga, et al.
(författare)
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Image statistics of the environment surrounding freely behaving hoverflies
- 2019
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Ingår i: Journal of Comparative Physiology A. Sensory, neural, and behavioral physiology. - : Springer. - 0340-7594 .- 1432-1351. ; 205:3, s. 373-385
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Tidskriftsartikel (refereegranskat)abstract
- Natural scenes are not as random as they might appear, but are constrained in both space and time. The 2-dimensional spatial constraints can be described by quantifying the image statistics of photographs. Human observers perceive images with naturalistic image statistics as more pleasant to view, and both fly and vertebrate peripheral and higher order visual neurons are tuned to naturalistic image statistics. However, for a given animal, what is natural differs depending on the behavior, and even if we have a broad understanding of image statistics, we know less about the scenes relevant for particular behaviors. To mitigate this, we here investigate the image statistics surrounding Episyrphus balteatus hoverflies, where the males hover in sun shafts created by surrounding trees, producing a rich and dense background texture and also intricate shadow patterns on the ground. We quantified the image statistics of photographs of the ground and the surrounding panorama, as the ventral and lateral visual field is particularly important for visual flight control, and found differences in spatial statistics in photos where the hoverflies were hovering compared to where they were flying. Our results can, in the future, be used to create more naturalistic stimuli for experimenter-controlled experiments in the laboratory.
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| 10. |
- Geurten, Bart, et al.
(författare)
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Neural mechanisms underlying target detection in a dragonfly centrifugal neuron.
- 2007
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 210:18, s. 3277-3284
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Tidskriftsartikel (refereegranskat)abstract
- Visual identification of targets is an important task for many animals searching for prey or conspecifics. Dragonflies utilize specialized optics in the dorsal acute zone, accompanied by higher-order visual neurons in the lobula complex, and descending neural pathways tuned to the motion of small targets. While recent studies describe the physiology of insect small target motion detector (STMD) neurons, little is known about the mechanisms that underlie their exquisite sensitivity to target motion. Lobula plate tangential cells (LPTCs), a group of neurons in dipteran flies selective for wide-field motion, have been shown to take input from local motion detectors consistent with the classic correlation model developed by Hassenstein and Reichardt in the 1950s. We have tested the hypothesis that similar mechanisms underlie the response of dragonfly STMDs. We show that an anatomically characterized centrifugal STMD neuron (CSTMD1) gives responses that depend strongly on target contrast, a clear prediction of the correlation model. Target stimuli are more complex in spatiotemporal terms than the sinusoidal grating patterns used to study LPTCs, so we used a correlation-based computer model to predict response tuning to velocity and width of moving targets. We show that increasing target width in the direction of travel causes a shift in response tuning to higher velocities, consistent with our model. Finally, we show how the morphology of CSTMD1 allows for impressive spatial interactions when more than one target is present in the visual field.
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