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1.
J Exp Biol ; 227(7)2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38323461

ABSTRACT

Natural variation in environmental turbidity correlates with variation in the visual sensory system of many fishes, suggesting that turbidity may act as a strong selective agent on visual systems. Since many aquatic systems experience increased turbidity due to anthropogenic perturbations, it is important to understand the degree to which fish can respond to rapid shifts in their visual environment, and whether such responses can occur within the lifetime of an individual. We examined whether developmental exposure to turbidity (clear, <5 NTU; turbid, ∼9 NTU) influenced the size of morphological structures associated with vision in the African blue-lip cichlid Pseudocrenilabrus multicolor. Parental fish were collected from two sites (clear swamp, turbid river) in western Uganda. F1 broods from each population were split and reared under clear and turbid rearing treatments until maturity. We measured morphological traits associated with the visual sensory system (eye diameter, pupil diameter, axial length, brain mass, optic tectum volume) over the course of development. Age was significant in explaining variation in visual traits even when standardized for body size, suggesting an ontogenetic shift in the relative size of eyes and brains. When age groups were analyzed separately, young fish reared in turbid water grew larger eyes than fish reared in clear conditions. Population was important in the older age category, with swamp-origin fish having relatively larger eyes and optic lobes relative to river-origin fish. Plastic responses during development may be important for coping with a more variable visual environment associated with anthropogenically induced turbidity.


Subject(s)
Cichlids , Animals , Cichlids/physiology , Eye , Brain/anatomy & histology , Fresh Water/chemistry , Vision, Ocular
2.
Atten Percept Psychophys ; 85(7): 2515-2530, 2023 Oct.
Article in English | MEDLINE | ID: mdl-36918511

ABSTRACT

Identifying the behaviors of organisms is essential for an animal's survival. This ability is particularly challenged when the "actors" are dynamically occluded by other objects and become fragmented as they move through an environment. Even when fragmented in time and across space, humans readily recognize the behavior of these dynamically occluded objects and actors. How animals process such fragmented information, especially when involving motion, remains uncertain. In three experiments, we investigated the ability of six pigeons to discriminate between the running and walking actions of digital animal models when dynamically occluded. The pigeons were tested in a go/no-go procedure using three models that transited behind multiple occluders in a semirealistic scene. Without ever seeing the entirety of the animal model at one time, all the pigeons learned to discriminate among these two behaviors. This discrimination transferred to an unfamiliar model, transit direction, transiting rates, camera perspectives, and occluders. Tests with different static and dynamic features indicated that the pigeons relied on motion features for the discrimination, especially articulated motion. These experiments demonstrate that pigeons, like humans, can discriminate actions even when their view of the actor is fragmented in time and space.


Subject(s)
Discrimination Learning , Motion Perception , Animals , Humans , Columbidae , Motion , Recognition, Psychology , Pattern Recognition, Visual
3.
Dementia (London) ; 22(3): 514-532, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36760075

ABSTRACT

Frontotemporal dementia describes a spectrum of disorders which include behavioural changes, changes to affect, speech difficulties and physical issues. Although literature exists which identifies the need for the voices of people with dementia to be heard, there is a paucity of research which includes hearing the experiences of people diagnosed with FTD. The purpose of this research was to explore the lived experience of frontotemporal dementia from the persons' perspective using interpretative phenomenological analysis. The themes that emerged in the analysis were: the rocky road through assessment; the changing self; in touch with reality; and keeping going. Two overarching themes emerged which were: the need to hear the voice of people with frontotemporal dementia; and for people with frontotemporal dementia to exercise some control over the decision making process throughout their journey. Recommendations are presented for future practice and research.


Subject(s)
Frontotemporal Dementia , Humans , Qualitative Research
4.
Clin Child Psychol Psychiatry ; 27(1): 122-135, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34289747

ABSTRACT

BACKGROUND: There is little understanding of the mental health impact for young people with long-term physical health conditions and mental health professionals' experiences of supporting them during COVID-19. This service evaluation aimed to conduct a survey of the psychological services provided by mental health professionals in a paediatric hospital in relation to COVID-19. METHOD: Clinical psychologists and assistant psychologists (n = 76) across the hospital were asked to complete a survey, asking about their perceptions of COVID-19's impact on patients and families and experiences of providing support during COVID-19. Open-ended survey questions were analysed qualitatively using framework analysis. RESULTS: Respondents described perceived impacts on patients and families around social isolation, school closure, family relationships, physical health, mental health, treatments and social support. Respondents' experiences of providing mental health support during COVID-19 highlighted themes around providing remote/virtual support, workload and facilitators and barriers to their work. CONCLUSIONS: Mental health professionals surveyed reported a complex mental health landscape in young people with long-term physical health conditions and their families during COVID-19. Service-wide involvement is needed to facilitate changes to support vital adaptations to remote/virtual working. Research on the mental health of young people with long-term physical health conditions and staff experiences of providing support is warranted.


Subject(s)
COVID-19 , Mental Health , Adolescent , Child , Hospitals, Pediatric , Humans , SARS-CoV-2 , Surveys and Questionnaires
5.
J Exp Psychol Anim Learn Cogn ; 48(1): 46-59, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34780235

ABSTRACT

To study comparative attentional allocation strategies, pigeons and humans were tested using simultaneously available discrimination tasks. Given visual search displays containing 32 items from two orthogonal dimensions, participants were reinforced for selecting the eight brightest (or darkest) of 16 brightness items and the eight most vertical (or horizontal) of 16 orientation items. Consistent with a sequential dimensional strategy, humans preferentially chose items from one dimension before switching to the other to complete the search. In contrast, the pigeons did not preferentially stay within one dimension over consecutive choices. Instead, they chose the items most likely to yield reward based on item discriminability. Computational models that incorporated a "dimensional staying" factor accounted best for the human data, while simulations using only discriminability reproduced the pigeons' data. These results suggest that humans are sensitive to the benefits of attentional staying and the costs of switching between dimensional tasks, while there was no evidence that these factors influenced the pigeons' choice behavior. These findings suggest fundamental differences in how pigeons and humans allocate attention in complex choice situations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Columbidae , Discrimination Learning , Animals , Attention , Cognition , Humans , Pattern Recognition, Visual , Photic Stimulation
6.
Rheumatol Adv Pract ; 5(3): rkab062, 2021.
Article in English | MEDLINE | ID: mdl-34671713

ABSTRACT

OBJECTIVES: Juvenile Dermatomyositis (JDM) is a rare, chronic autoimmune condition of childhood, with known psychosocial implications. In this study, we sought to establish current psychological support for children and young people across the UK with rheumatic conditions, with a specific focus on those with JDM. METHODS: Electronic surveys were distributed to the 15 centres that belong to the JDM Research Group in the UK, collecting responses from health-care professionals in the fields of medicine, nursing and psychology. RESULTS: One hundred per cent of professionals from medicine and nursing replied from all 15 centres. Of these, 7 (47%) did not have a named psychologist as part of their rheumatology team, despite the majority [13 (87%)] having >200 paediatric rheumatology patients. Of the remaining centres, hospital psychology provision varied considerably. When rating their service, only 3 (8%) of 40 professionals scored their service as five (where one is poor and five is excellent); there were wide discrepancies in these scores. Many challenges were discussed, including limited psychology provision, lack of time and difficulties in offering support across large geographical areas. CONCLUSION: Many of the challenges discussed are applicable to other centres worldwide. Suggestions have been proposed that might help to improve the situation for children and young people with rheumatic conditions, including JDM. Based on these findings, we suggest that rheumatology teams maximize use of these data to advocate and work toward more comprehensive psychology provision and support in their individual centres.

7.
BMJ Paediatr Open ; 5(1): e001147, 2021.
Article in English | MEDLINE | ID: mdl-34337164

ABSTRACT

Background: Children undergoing surgery and their parents are at risk of developing post-traumatic stress reactions. We systematically reviewed the literature to understand the prevalence of this issue, as well as potential risk factors. Methods: We conducted a systematic review and meta-analysis, using PubMed, PsycInfo, Web of Science and Google Scholar, with searches conducted in February 2021. Papers were included if they measured post-traumatic stress in children and/or parents following paediatric surgery and were excluded if they did not use a validated measure of post-traumatic stress. Data were extracted from published reports. Findings: Our search yielded a total of 1672 papers, of which 16 met our inclusion criteria. In meta-analysis, pooled studies of children estimated an overall prevalence of 16% meeting criteria for post-traumatic stress disorder post surgery (N=187, 95% CI 5% to 31%, I2=80%). After pooling studies of parents, overall prevalence was estimated at 23% (N=1444, 95% CI 16% to 31%, I2=91%). Prevalence rates were higher than those reported in the general population. Risk factors reported within studies included length of stay, level of social support and parental mental health. Interpretation: There is consistent evidence of traumatic stress following surgery in childhood which warrants further investigation. Those delivering surgical care to children would benefit from a raised awareness of the potential for post-traumatic stress in their patients and their families, including offering screening and support.


Subject(s)
Stress Disorders, Post-Traumatic , Child , Humans , Parents , Prevalence , Risk Factors , Stress Disorders, Post-Traumatic/epidemiology , Stress, Psychological/epidemiology
8.
Learn Behav ; 49(1): 85-98, 2021 03.
Article in English | MEDLINE | ID: mdl-32968857

ABSTRACT

The perception of a complex scene requires visual mechanisms that include identifying objects and their relative placement in depth. To examine apparent depth perception in birds, we tested four pigeons with a novel multiple-sequential-choice procedure. We created 3D-rendered scene stimuli containing three objects located at different apparent depths based on a variety of pictorial cues and placed small circular target response areas on them. The pigeons were trained to sequentially choose among the multiple response areas to report the object closest in apparent depth (ordinal position; front then middle object). After the pigeons learned this sequential depth discrimination, their use of three different monocular depth cues (occlusion, relative size, height in field) was tested, and their flexibility evaluated using three novel objects. In addition to the contribution to understanding apparent depth perception in birds, the use of more flexible open-ended choice discriminations, as employed here, has considerable promise for creating informative production-like tasks in nonverbal animals.


Subject(s)
Columbidae , Cues , Animals , Discrimination Learning
9.
Conserv Physiol ; 8(1): coaa019, 2020.
Article in English | MEDLINE | ID: mdl-32274066

ABSTRACT

The field of conservation physiology strives to achieve conservation goals by revealing physiological mechanisms that drive population declines in the face of human-induced rapid environmental change (HIREC) and has informed many successful conservation actions. However, many studies still struggle to explicitly link individual physiological measures to impacts across the biological hierarchy (to population and ecosystem levels) and instead rely on a 'black box' of assumptions to scale up results for conservation implications. Here, we highlight some examples of studies that were successful in scaling beyond the individual level, including two case studies of well-researched species, and using other studies we highlight challenges and future opportunities to increase the impact of research by scaling up the biological hierarchy. We first examine studies that use individual physiological measures to scale up to population-level impacts and discuss several emerging fields that have made significant steps toward addressing the gap between individual-based and demographic studies, such as macrophysiology and landscape physiology. Next, we examine how future studies can scale from population or species-level to community- and ecosystem-level impacts and discuss avenues of research that can lead to conservation implications at the ecosystem level, such as abiotic gradients and interspecific interactions. In the process, we review methods that researchers can use to make links across the biological hierarchy, including crossing disciplinary boundaries, collaboration and data sharing, spatial modelling and incorporating multiple markers (e.g. physiological, behavioural or demographic) into their research. We recommend future studies incorporating tools that consider the diversity of 'landscapes' experienced by animals at higher levels of the biological hierarchy, will make more effective contributions to conservation and management decisions.

10.
Pediatr Rheumatol Online J ; 17(1): 30, 2019 Jun 18.
Article in English | MEDLINE | ID: mdl-31215480

ABSTRACT

BACKGROUND: Juvenile Dermatomyositis is a rare, potentially life-threatening condition with no known cure. There is no published literature capturing how children and young people feel about their condition, from their perspective. This study was therefore unique in that it asked children and young people what is it like to live with Juvenile Dermatomyositis. METHODS: Data were obtained from fifteen young people with Juvenile Dermatomyositis, between eight and nineteen years of age from one Paediatric Rheumatology department using audio-recorded interpretive phenomenology interviews. Data were analyzed phenomenologically, using a process that derives narratives from transcripts resulting in a collective composite of participants shared experiences, called a 'phenomenon'. RESULTS: The overarching metaphor of a rollercoaster captures the phenomenon of living with Juvenile Dermatomyositis as a young person, with the ups and downs at different time points clearly described by those interviewed. The five themes plotted on the rollercoaster, began with confusion; followed by feeling different, being sick, steroidal and scared from the medications; uncertainty; and then ended with acceptance of the disease over time. CONCLUSION: Young people were able to talk about their experiences about having Juvenile Dermatomyositis. Our findings will aid clinicians in their practice by gaining a deeper understanding of what daily life is like and highlighting ways to enhance psychosocial functioning. Hopefully, this study and any further resulting studies, will raise understanding of Juvenile Dermatomyositis worldwide and will encourage health care professionals to better assess psychosocial needs in the future.


Subject(s)
Dermatomyositis/psychology , Activities of Daily Living , Adaptation, Psychological , Adolescent , Attitude to Health , Child , Child, Preschool , Chronic Disease , Confusion/psychology , Dermatologic Agents/therapeutic use , Dermatomyositis/drug therapy , Female , Humans , Interpersonal Relations , Male , Methotrexate/therapeutic use , Quality of Life , Rare Diseases , Self Concept , Steroids/therapeutic use
11.
Curr Zool ; 65(1): 33-42, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30697236

ABSTRACT

Animals are increasingly faced with human-induced stressors that vary in space and time, thus we can expect population-level divergence in behaviors that help animals to cope with environmental change. However, empirical evidence of behavioral trait divergence across environmental extremes is lacking. We tested for variation in behavioral traits among 2 populations of an African cichlid fish (Pseudocrenilabrus multicolor victoriae Seegers, 1990) that experience extremes of dissolved oxygen (DO) and turbidity and are known to vary in a number of physiological and life history traits associated with these stressors. Using a common garden rearing experiment, F1 progeny from wild-caught parents originating from a swamp (low DO, clear) and a river (high DO, turbid) were reared in high DO, clear water. Predator simulation assays were conducted to test for (1) variation in boldness, general activity, and foraging activity between populations, (2) differences in correlations between behaviors within and across populations, and (3) repeatability of behaviors. There was strong evidence for divergence between populations, with swamp fish being more bold (i.e., leaving refuge sooner after a simulated predator attack) and active (i.e., spent more time out of refuge) than river fish. Across populations there were positive correlations between foraging activity and both boldness and general activity; however, within populations, there was only a strong positive relationship between foraging activity and boldness in the river population. Here, we have demonstrated that populations that originate from drastically different environments can produce progeny that exhibit measurable differences in behaviors and their correlated relationships even when reared under common conditions.

12.
J Fish Biol ; 95(1): 186-199, 2019 Jul.
Article in English | MEDLINE | ID: mdl-30511351

ABSTRACT

The objectives of this study were to determine the effects of different forms of elevated turbidity on the visual acuity of two native Lake Erie fishes and to assess the response of fishes from different trophic levels to elevated turbidity. Additionally, the role of visual morphology (e.g., eye and optic lobe size) on visual acuity was evaluated across visual environments. Reaction distance, a behavioural proxy for measures of visual acuity, was measured for a top predator, walleye Sander vitreus and a forage fish, emerald shiner Notropis atherinoides. In both S. vitreus (n = 27) and N. atherinoides (n = 40) reaction distance across all types of turbidity (sedimentary, algal, sedimentary + algal; 20 NTU) was approximately 50% lower relative to the clear treatment. Reaction distance was further reduced in algal compared with sedimentary turbidity for wild-caught S. vitreus. Eye and brain morphology also influenced reaction distance across turbidity treatments, such that larger relative eye and brain metrics were positively correlated with reaction distance. This study provides evidence for disrupted visual acuity as a potential mechanism underlying fish responses, such as decreased foraging efficiency, to increased turbidity and further indicates that algal turbidity will probably be more detrimental to visual processes than sedimentary turbidity. With the increasing occurrence and severity of harmful algal blooms due to cultural eutrophication globally, this could have significant implications for predator-prey relationships in aquatic systems.


Subject(s)
Cyprinidae/physiology , Environment , Perciformes/physiology , Visual Perception , Animals , Appalachian Region , Lakes , Nephelometry and Turbidimetry , Principal Component Analysis , Visual Acuity , Water
13.
Conserv Physiol ; 6(1): coy044, 2018.
Article in English | MEDLINE | ID: mdl-30135737

ABSTRACT

Increasing anthropogenic turbidity is among the most prevalent disturbances in freshwater ecosystems, through increases in sedimentary deposition as well as the rise of nutrient-induced algal blooms. Changes to the amount and color of light underwater as a result of elevated turbidity are likely to disrupt the visual ecology of fishes that rely on vision to survive and reproduce; however, our knowledge of the mechanisms underlying visual responses to turbidity is lacking. First, we aimed to determine the visual detection threshold, a measure of visual sensitivity, of two ecologically and economically important Lake Erie fishes, the planktivorous forage fish, emerald shiner (Notropis atherinoides), and a primary predator, the piscivorous walleye (Sander vitreus), under sedimentary and algal turbidity. Secondly, we aimed to determine if these trophically distinct species are differentially impacted by increased turbidity. We used the innate optomotor response to determine the turbidity levels at which individual fish could no longer detect a difference between a stimulus and the background (i.e. visual detection threshold). Detection thresholds were significantly higher in sedimentary compared to algal turbidity for both emerald shiner (meansediment ± SE = 79.66 ± 5.51 NTU, meanalgal ± SE = 34.41 ± 3.19 NTU) and walleye (meansediment ± SE = 99.98 ± 5.31 NTU, meanalgal ± SE = 40.35 ± 2.44 NTU). Our results suggest that across trophic levels, the visual response of fishes will be compromised under algal compared to sedimentary turbidity. The influence of altered visual environments on the ability of fish to find food and detect predators could potentially be large, leading to population- and community-level changes within the Lake Erie ecosystem.

14.
J Comp Psychol ; 132(2): 166-177, 2018 05.
Article in English | MEDLINE | ID: mdl-29528667

ABSTRACT

Research has shown that some forms of inferential reasoning are likely widespread throughout the animal kingdom (e.g., exclusion, in which a subject infers the placement of a reward by eliminating potential alternative sites), but other types of inferential tasks have not been extensively tested. We examined whether a nonhuman might succeed in an experiment based on probabilistic reasoning, specifically, the ability to make inferences about a sample based on information about a population. A Grey parrot (Psittacus erithacus), previously trained to use English labels referentially to identify objects, observed a human researcher deposit 2 different types of items in a 3:1 ratio (e.g., 3 corks and 1 piece of paper) into an opaque bucket. One item was then randomly withdrawn while hidden from the parrot's view. When asked to identify the still-hidden object, the parrot's vocal responses tracked this 3:1 ratio over a large number of trials. Some levels of probabilistic reasoning therefore are not limited to humans, nonhuman primates, or even mammals. (PsycINFO Database Record


Subject(s)
Behavior, Animal/physiology , Cognition/physiology , Parrots , Probability , Animals , Humans
15.
J Comp Psychol ; 131(4): 370-383, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28857607

ABSTRACT

An understanding of Piagetian liquid conservation was investigated in four Grey parrots (Psittacus erithacus), their ages ranging from initially less than 1 year old to 18 years old. They were tested in several conditions: on the ability to choose between (a) identical containers filled with a greater or lesser quantity of a desirable liquid to see if they would reliably take the larger amount and (b) equal quantities of liquid that were visibly or invisibly transferred from identical to different-sized containers to examine their abilities with respect to conservation. Invisible transfers examined the extent to which birds chose based on perceptual evaluations of quantity and the effects of task order on their decisions. Adult birds succeeded on all or most aspects of the tests. As a chick (∼6 months), 1 bird was unable or unwilling to choose between the smaller and larger quantities in the first stage of testing, but upon reaching juvenile status succeeded in all aspects of the tests. Grey parrots thus demonstrate some understanding of liquid conservation. (PsycINFO Database Record


Subject(s)
Behavior, Animal/physiology , Choice Behavior/physiology , Parrots/physiology , Size Perception/physiology , Thinking/physiology , Visual Perception/physiology , Animals , Female , Male
16.
J Phys Chem B ; 120(23): 5301-11, 2016 06 16.
Article in English | MEDLINE | ID: mdl-27203286

ABSTRACT

A range of liquid rare earth chlorometallate complexes with the alkyl-phosphonium cation, [P666 14](+), has been synthesized and characterized. EXAFS confirmed the predominant liquid-state speciation of the [LnCl6](3-) ion in the series with Ln = Nd, Eu, Dy. The crystal structure of the shorter-alkyl-chain cation analogue [P4444](+) has been determined and exhibits a very large unit cell. The luminescence properties, with visible-light emissions of the liquid Tb, Eu, Pr, and Sm and the NIR emissions for the Nd and Er compounds, were determined. The effective magnetic moments were measured and fitted for the Nd, Tb, Ho, Dy, Gd, and Er samples.

17.
J Comp Psychol ; 129(4): 339-46, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26214033

ABSTRACT

Delay of gratification, the ability to forgo an immediate reward to gain either better quality or quantity, has been used as a metric for temporal discounting, self-control, and the ability to plan for the future in both humans (particularly children) and nonhumans. The task involved can be parsed in several ways, such that the subjects can be required to wait, not only for a better or a larger reward, but also such that the rewards can either be in view or hidden during the delay interval. We have demonstrated that a Grey parrot (Psittacus erithacus) trained in the use of English speech could respond to the label "wait" for up to 15 min, in a task that has many similarities to those used with young children, to receive a better quality reward, whether or not the better quality reward or the experimenter was in view.


Subject(s)
Behavior, Animal/physiology , Delay Discounting/physiology , Parrots/physiology , Reward , Animals , Male
18.
Anim Cogn ; 17(4): 937-44, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24474186

ABSTRACT

In a previous study (Péron et al. in Anim Cogn, doi: 10.1007/s10071-012.05640 , 2012), Grey parrots, working in dyads, took turns choosing one of four differently coloured cups with differing outcomes: empty (null, non-rewarding), selfish (keeping reward for oneself), share (sharing a divisible reward), or giving (donating reward to other). When the dyads involved three humans with different specific intentions (selfish, giving, or copying the bird's behaviour), birds' responses only tended towards consistency with human behaviour. Our dominant bird was willing to share a reward with a human who was willing to give up her reward, was selfish with the selfish human, and tended towards sharing with the copycat human; our subordinate bird tended slightly towards increased sharing with the generous human and selfishness with the selfish human, but did not clearly mirror the behaviour of the copycat. We theorized that the birds' inability to understand the copycat condition fully-that they could potentially maximize reward by choosing to share-was a consequence of their viewing the copycat's behaviour as erratic compared with the consistently selfish or giving humans and thus not realizing that they were indeed being mirrored. We suggested that copycat trials subsequently be performed as a separate experiment, without being contrasted with trials in which humans acted consistently, in order to determine if results might have differed. We have now performed that experiment, and shown that at least one Grey parrot--our dominant--responded in a manner suggesting that he deduced the appropriate contingencies.


Subject(s)
Altruism , Human-Animal Bond , Parrots , Animals , Choice Behavior , Female , Humans , Imitative Behavior , Male , Reward
19.
J Exp Biol ; 216(Pt 9): 1670-82, 2013 May 01.
Article in English | MEDLINE | ID: mdl-23393278

ABSTRACT

Humans use three cone photoreceptor classes for colour vision, yet many birds, reptiles and shallow-water fish are tetrachromatic and use four cone classes. Screening pigments, which narrow the spectrum of photoreceptors in birds and diurnal reptiles, render visual systems with four cone classes more efficient. To date, however, the question of tetrachromacy in shallow-water fish that, like humans, lack screening pigments, is still unsolved. We raise the possibility that tetrachromacy in fish has evolved in response to higher spectral complexity of underwater light. We compared the dimensionality of colour vision in humans and fish by examining the spectral complexity of the colour signal reflected from objects into their eyes. We show that fish require four to six cone classes to reconstruct the colour signal of aquatic objects at the accuracy level achieved by humans viewing terrestrial objects. This is because environmental light, which alters the colour signals, is more complex and contains more spectral fluctuations underwater than on land. We further show that fish cones are better suited than human cones to detect these spectral fluctuations, suggesting that the capability of fish cones to detect high-frequency fluctuations in the colour signal confers an advantage. Taken together, we propose that tetrachromacy in fish has evolved to enhance the reconstruction of complex colour signals in shallow aquatic environments. Of course, shallow-water fish might possess fewer than four cone classes; however, this would come with the inevitable loss in accuracy of signal reconstruction.


Subject(s)
Aquatic Organisms/physiology , Aquatic Organisms/radiation effects , Biological Evolution , Color Vision/physiology , Fishes/physiology , Light , Water , Animals , Color Vision/radiation effects , Humans , Linear Models , Principal Component Analysis , Spectrum Analysis , Thermodynamics
20.
Emerg Med Australas ; 24(5): 560-5, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23039299

ABSTRACT

OBJECTIVES: Irukandji syndrome is a distressing condition characterised by pain, hypertension and tachycardia. Some develop cardiac failure and there have been two reported deaths. Magnesium sulphate has become the standard of care despite minimal evidence. The aim of this study was to investigate if magnesium would reduce analgesic requirement and length of stay for patients with Irukandji syndrome. METHODS: This was a double-blind, randomised controlled clinical trial. Patients with Irukandji syndrome who required parenteral opioid analgesia were randomised to receive either 10 mmol of magnesium as a bolus, and then a 5 mmol/h magnesium infusion for 6 h or saline. Fentanyl patient-controlled analgesia was commenced to allow patients to self-regulate their pain relief. The primary outcome measure of the study was comparison of total analgesic requirements between the two groups. The secondary outcome measure was to compare length of stay. RESULTS: The study ran from November 2003 to May 2007. Thirty-nine patients were enrolled in the study; 26 were male with a median age of 28. Twenty-two received magnesium. There was no significant difference in the morphine equivalent dose used, peak CK, peak troponin, peak pulse, peak blood pressure, peak mean arterial pressure (MAP), percentage MAP rise and length of stay for those receiving magnesium compared with placebo. CONCLUSION: Our study did not demonstrate a benefit in the use of magnesium in the treatment of Irukandji syndrome. As such the current use of magnesium needs to be reconsidered until there is good evidence to support its use.


Subject(s)
Analgesics/therapeutic use , Bites and Stings/drug therapy , Cnidarian Venoms/adverse effects , Cubozoa/chemistry , Magnesium Sulfate/therapeutic use , Pain/drug therapy , Adolescent , Adult , Aged , Analgesia, Patient-Controlled , Analgesics, Opioid/therapeutic use , Analysis of Variance , Animals , Bites and Stings/pathology , Cnidarian Venoms/chemistry , Confidence Intervals , Double-Blind Method , Female , Fentanyl/therapeutic use , Humans , Male , Middle Aged , Pain/etiology , Young Adult
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