RESUMO
In many contexts, animals assess each other using signals that vary continuously across individuals and, on average, reflect variation in the quality of the signaller1,2. It is often assumed that signal receivers perceive and respond continuously to continuous variation in the signal2. Alternatively, perception and response may be discontinuous3, owing to limitations in discrimination, categorization or both. Discrimination is the ability to tell two stimuli apart (for example, whether one can tell apart colours close to each other in hue). Categorization concerns whether stimuli are grouped based on similarities (for example, identifying colours with qualitative similarities in hue as similar even if they can be distinguished)4. Categorical perception is a mechanism by which perceptual systems categorize continuously varying stimuli, making specific predictions about discrimination relative to category boundaries. Here we show that female zebra finches (Taeniopygia guttata) categorically perceive a continuously variable assessment signal: the orange to red spectrum of male beak colour. Both predictions of categorical perception5 were supported: females (1) categorized colour stimuli that varied along a continuum and (2) showed increased discrimination between colours from opposite sides of a category boundary compared to equally different colours from within a category. To our knowledge, this is the first demonstration of categorical perception of signal-based colouration in a bird, with implications for understanding avian colour perception and signal evolution in general.
Assuntos
Percepção de Cores/fisiologia , Tentilhões/fisiologia , Animais , Bico/anatomia & histologia , Carotenoides/análise , Carotenoides/metabolismo , Cor , Feminino , Tentilhões/imunologia , Imunidade Celular , Masculino , Preferência de Acasalamento Animal/fisiologia , Estimulação Luminosa , Pigmentação/fisiologiaRESUMO
AbstractSensory systems are predicted to be adapted to the perception of important stimuli, such as signals used in communication. Prior work has shown that female zebra finches perceive the carotenoid-based orange-red coloration of male beaks-a mate choice signal-categorically. Specifically, females exhibited an increased ability to discriminate between colors from opposite sides of a perceptual category boundary than equally different colors from the same side of the boundary. The Bengalese finch, an estrildid finch related to the zebra finch, is black, brown, and white, lacking carotenoid coloration. To explore the relationship between categorical color perception and signal use, we tested Bengalese finches using the same orange-red continuum as in zebra finches, and we also tested how both species discriminated among colors differing systematically in hue and brightness. Unlike in zebra finches, we found no evidence of categorical perception of an orange-red continuum in Bengalese finches. Instead, we found that the combination of chromatic distance (hue difference) and Michelson contrast (difference in brightness) strongly correlated with color discrimination ability on all tested color pairs in Bengalese finches. The pattern was different in zebra finches: this strong correlation held when discriminating between colors from different categories but not when discriminating between colors from within the same category. These experiments suggest that categorical perception is not a universal feature of avian-or even estrildid finch-vision. Our findings also provide further insights into the mechanism underlying categorical perception and are consistent with the hypothesis that categorical perception is adapted for signal perception.
Assuntos
Percepção de Cores/fisiologia , Cor , Tentilhões/fisiologia , Animais , Bico , Carotenoides , Condicionamento Operante , Discriminação Psicológica , FemininoRESUMO
Although perception begins when a stimulus is transduced by a sensory neuron, numerous perceptual mechanisms can modify sensory information as it is processed by an animal's nervous system. One such mechanism is categorical perception, in which (1) continuously varying stimuli are labelled as belonging to a discrete number of categories and (2) there is enhanced discrimination between stimuli from different categories as compared with equally different stimuli from within the same category. We have shown previously that female zebra finches ( Taeniopygia guttata) categorically perceive colours along an orange-red continuum that aligns with the carotenoid-based coloration of male beaks, a trait that serves as an assessment signal in female mate choice. Here, we demonstrate that categorical perception occurs along a blue-green continuum as well, suggesting that categorical colour perception may be a general feature of zebra finch vision. Although we identified two categories in both the blue-green and the orange-red ranges, we also found that individuals could better differentiate colours from within the same category in the blue-green as compared with the orange-red range, indicative of less clear categorization in the blue-green range. We discuss reasons why categorical perception may vary across the visible spectrum, including the possibility that such differences are linked to the behavioural or ecological function of different colour ranges.
Assuntos
Percepção de Cores , Aves Canoras/fisiologia , Comunicação Animal , Animais , Cor , Feminino , Estimulação LuminosaRESUMO
Cleaner shrimp and their reef fish clients are an interspecific mutualistic interaction that is thought to be mediated by signals, and a useful system for studying the dynamics of interspecific signalling. To demonstrate signalling, one must show that purported signals at minimum (a) result in a consistent state change in the receiver and (b) contain reliable information about the sender's intrinsic state or future behaviour. Additionally, signals must be perceptible by receivers. Here, we document fundamental attributes of the signalling system between the cleaner shrimp Ancylomenes pedersoni and its clients. First, we use sequential analysis of in situ behavioural interactions to show that cleaner antenna whipping reliably predicts subsequent cleaning. If shrimp do not signal via antenna whipping, clients triple their likelihood of being cleaned by adopting darker coloration over a matter of seconds, consistent with dark colour change signalling that clients want cleaning. Using experimental manipulations, we found that visual stimuli are sufficient to elicit antenna whipping, and that shrimp are more likely to 'clean' dark than light visual stimuli. Lastly, we show that antenna whipping and colour change are perceptible when accounting for the intended receiver's visual acuity and spectral sensitivity, which differ markedly between cleaners and clients. Our results show that signalling by both cleaners and clients can initiate and mediate their mutualistic interaction.
Assuntos
Comunicação Animal , Peixes/fisiologia , Palaemonidae/fisiologia , Simbiose , Percepção Visual , Animais , Sinais (Psicologia) , Curaçao , Estimulação LuminosaRESUMO
Purpose We aimed to investigate association between bibliometric parameters, reporting and methodological quality of vascular and endovascular surgery randomised controlled trials. Methods The most recent 75 and oldest 75 randomised controlled trials published in leading journals over a 10-year period were identified. The reporting quality was analysed using the CONSORT statement, and methodological quality with the Intercollegiate Guidelines Network checklist. We used exploratory univariate and multivariable linear regression analysis to investigate associations. Findings Bibliometric parameters such as type of journal, study design reported in title, number of pages; external funding, industry sponsoring and number of citations are associated with reporting quality. Moreover, parameters such as type of journal, subject area and study design reported in title are associated with methodological quality. Conclusions The bibliometric parameters of randomised controlled trials may be independent predictors for their reporting and methodological quality. Moreover, the reporting quality of randomised controlled trials is associated with their methodological quality and vice versa.
Assuntos
Coleta de Dados/normas , Procedimentos Endovasculares/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Projetos de Pesquisa/normas , Procedimentos Cirúrgicos Vasculares/normas , Bibliometria , Lista de Checagem , Coleta de Dados/estatística & dados numéricos , Interpretação Estatística de Dados , Humanos , Modelos Lineares , Análise Multivariada , Guias de Prática Clínica como Assunto , Controle de Qualidade , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Projetos de Pesquisa/estatística & dados numéricos , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares/estatística & dados numéricosRESUMO
Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues.
Assuntos
Carnívoros/anatomia & histologia , Modelos Anatômicos , Respiração , Olfato/fisiologia , Conchas Nasais/anatomia & histologia , Animais , Comportamento Apetitivo/fisiologia , Pesos e Medidas Corporais , Carnívoros/fisiologia , Dieta , Feminino , Masculino , Filogenia , Especificidade da Espécie , Tomografia Computadorizada por Raios X , Conchas Nasais/fisiologiaRESUMO
Background/Purpose Oesophageal Atresia (OA) is associated with co-existent anomalies. There is a controversy of literature pertaining to the risk (s) of intestinal malrotation. In order to guide management we critically evaluate the incidence of IM anomalies in OA newborns. Design MEDLINE and EMBASE databases were searched using keywords "(O)Esophageal Atresia and Malrotation/Associated Abnormalities/Associated Anomalies". Full texts of articles were screened if manuscripts exclusively reported patients with OA malrotation and/or associated anomalies. Larger case series (> 10patients) were included if abstract (s) showed that associated anomalies were systematically assessed. Full eligibility criteria required at least one case of malrotation in an OA index case. Data were collected on article type, number of patients and method (s) of diagnosis. Results 632 abstracts were screened of which 158 papers were analysed based on inclusion criteria-30 manuscripts documented the incidence (%) of malrotation. Incidence rate (s) were 0.5-13%. Malrotation was observed to have a higher incidence (10-44%) in OA babies with other gastrointestinal anomalies (VACTERL). Conclusion Newborns with OA appear to be at a higher risk (%) of having intestinal malrotation anomalies than healthy babies. Prospective studies are required to accurately quantify and define the ' true incidence ' of this association. Given the potential lethal consequences of midgut volvulus screening may be justified in OA babies. Consensus guidelines (DELPHI) exploring surgeons attitudes with regards management of ' asymptomatic malrotation ' disorders in OA newborns may further guide best practice.
Assuntos
Anormalidades do Sistema Digestório , Atresia Esofágica , Volvo Intestinal , Anormalidades do Sistema Digestório/diagnóstico , Anormalidades do Sistema Digestório/epidemiologia , Atresia Esofágica/complicações , Atresia Esofágica/diagnóstico , Atresia Esofágica/epidemiologia , Humanos , Incidência , Lactente , Recém-Nascido , Volvo Intestinal/complicações , Volvo Intestinal/diagnóstico , Volvo Intestinal/epidemiologiaRESUMO
Animals often use assessment signals to communicate information about their quality to a variety of receivers, including potential mates, competitors, and predators. But what maintains reliable signaling and prevents signalers from signaling a better quality than they actually have? Previous work has shown that reliable signaling can be maintained if signalers pay fitness costs for signaling at different intensities and these costs are greater for lower quality individuals than higher quality ones. Models supporting this idea typically assume that continuous variation in signal intensity is perceived as such by receivers. In many organisms, however, receivers have threshold responses to signals, in which they respond to a signal if it is above a threshold value and do not respond if the signal is below the threshold value. Here, we use both analytical and individual-based models to investigate how such threshold responses affect the reliability of assessment signals. We show that reliable signaling systems can break down when receivers have an invariant threshold response, but reliable signaling can be rescued if there is variation among receivers in the location of their threshold boundary. Our models provide an important step toward understanding signal evolution when receivers have threshold responses to continuous signal variation.
Assuntos
Comunicação Animal , Aptidão Genética , Modelos Biológicos , Animais , Coevolução Biológica , Feminino , Masculino , Preferência de Acasalamento AnimalRESUMO
INTRODUCTION: Circumcision has long been the mainstay of management for genitourinary lichen sclerosus et atrophicus (LS); however, there has been growing interest in surgical techniques that preserve the foreskin. OBJECTIVE: The aim of this study was to assess population-based surgical management of LS in England and determine surgical outcomes. STUDY DESIGN: Cases of LS treated in English NHS trusts (2002-2011) were extracted from the Hospital Episode Statistics (HES) Database. Cases were identified by both an ICD-10 code for LS and either an OPCS4.6 code for circumcision or preputioplasty (with/without injection of steroid). Subsequent admissions were analysed for related complications/procedures. Data are presented as median (interquartile range) unless otherwise stated. RESULTS: 7893 patients had surgery for LS, of whom 7567 (95.8%) underwent circumcision (Table). Primary preputioplasty was performed in 326 (4.1%) in 44/130 centres; of these 151/326 had concomitant injection of steroid. Age at surgical intervention was 9 (6-11) years. There were no postoperative bleeds following preputioplasty. Of those treated with preputioplasty, 74 (22%) had subsequent circumcision at a median of 677 (277-1203) days post operation. Concomitant steroid injection reduced the risk of subsequent circumcision (21/151 (14%) vs. 53/175 (30%), p < 0.001). More children underwent a second operative procedure following preputioplasty than those having had a primary circumcision (27.9% vs. 7.9%, p < 0.001). CONCLUSION: Although circumcision is the predominant treatment for LS, these data suggest that preputioplasty is a valid option in management, albeit with a higher re-intervention rate. Selection bias may play a role and a randomized controlled trial is needed. Preputioplasty combined with steroid injection appears to reduce the chance of completion circumcision.
Assuntos
Líquen Escleroso e Atrófico/cirurgia , Doenças Urogenitais Masculinas/cirurgia , Criança , Estudos de Coortes , Inglaterra , Humanos , Masculino , Padrões de Prática Médica , Fatores de Tempo , Resultado do Tratamento , Procedimentos Cirúrgicos Urológicos Masculinos/métodosRESUMO
INTRODUCTION: Hypospadias surgery has progressed steadily over recent years. There remains considerable variation in the operative management of boys with hypospadias in the UK, and it is therefore difficult to identify acceptable standards with regards to reoperation rates. OBJECTIVE: To determine the frequency of reoperations and complications from all centres performing hypospadias surgery in England and to identify variables that influence outcome. METHODS: All children undergoing NHS hypospadias surgery in England between 1999 and 2009 were identified using the Hospital Episode Statistics database. Patient demographics, centre type, and associated diagnostic (ICD-10) and treatment codes (OPCS4.6) were collected for both primary repairs and postoperative complications. Centres were classed as high volume if they performed an average of 20 or more operations a year. Operative complications were split into revisions (repeat repairs), repairs of urethral fistulae, repairs of meatal stenosis, or urethral stricture repairs. Statistical analysis included logistic regression, Spearman's correlation, and Mann-Whitney U for non-parametric data, with p < 0.05 taken as significant. Data are presented as median (interquartile range) unless otherwise stated. RESULTS: children underwent a total of 23,962 operations at 75 centres in England during the study period. The median age at primary repair was 21 (15-38) months. The overall complication rate was 18.1%. The median complication rate for individual centres was 20.0% (13.9-27.4%) overall; 10.8% (4.7-15.9%) for revision procedures, 8.1% (5.5-11.7%) for urethral fistulae, 2.3% (1.1-3.7%) for meatal stenosis repairs, and 1.8% (0-2.8%) for urethral strictures. High volume centres had significantly lower complication rates than low volume centres (17.5% vs. 25%, p = 0.01) (Figure), and this was proven to be an independent predictor of outcomes (p = 0.01). Staged repairs were associated with more complications (p < 0.001); however, patient age and centre type were not. Median time to repair of complication was 13 (8-22) months. DISCUSSION: This national population-based study used hospital episode statistics data. While accuracy is high and it has been validated for use in research, it has intrinsic limitations which affect our study. We are unable to fully account for the severity of hypospadias or the number of operating surgeons within institutions. CONCLUSIONS: This study has found a clear relationship between caseload volume and complications following hypospadias surgery. Furthermore, there is significant variability between centres in terms of their surgical outcomes. Taken together these results suggest that surgeons, particularly those in centres with small caseloads should assess their results against such benchmarks when evaluating the service they provide.
Assuntos
Hospitais com Alto Volume de Atendimentos , Hipospadia/cirurgia , Complicações Pós-Operatórias/epidemiologia , Pré-Escolar , Inglaterra , Humanos , Lactente , Masculino , Reoperação/estatística & dados numéricos , Estudos RetrospectivosRESUMO
OBJECTIVE: Intestinal malrotation classically presents in the neonatal period with bilious vomiting. However, population studies suggest that up to two-thirds of these patients are diagnosed later in childhood or in adulthood. Increased morbidity in the adult population has been reported. Local experience suggested that surgery was technically more difficult in older children and led to the hypothesis that it would be associated with increased morbidity. METHODS: A retrospective case note analysis was performed on all children presenting with intestinal malrotation to a tertiary referral center between January 2002 and November 2014. Case notes and operation records were reviewed and those who underwent laparotomy for confirmed malrotation were included. Children were grouped as infants (< 1 year) and older (> 1 year). The primary outcome was total emergency reoperation rate. Secondary outcomes were requirement for a bypass at reoperation and mortality. RESULTS: A total of 131 children with malrotation were identified (104 infants, 27 older children; 78 males; age range, 0-16 years). Overall, 13 patients had emergency reoperation following initial Ladd procedure (6 infants and 7 older children). Risk for reoperation was significantly higher in older children (p = 0.005) and additionally a bypass procedure was more often required in older children than infants (4 children, 2 infants, p = 0.016). Adhesiolysis was required on four occasions and redo Ladd procedure in two; these were evenly distributed between both groups. One child was found to have distal bowel obstruction at reoperation. There were three deaths (2.3%), all in the infant group. One was directly associated with malrotation with extensive bowel necrosis. The other two died of unrelated sepsis several months later. CONCLUSIONS: Malrotation surgery in older children is associated with a significantly higher emergency reoperation rate. The primary duodenal bypass procedure should always be considered with longstanding chronic intermittent obstruction associated with malrotation if the simple Ladd procedure is deemed inadequate.