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1.
Braz. j. biol ; 84: e253215, 2024. tab
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1360216

RESUMO

Abstract Frequencies, magnitudes, and distributions of occurrence can affect the events. The problem can be worse or the solution better if greater frequencies and magnitudes are presented with aggregated distribution in the production system. Indices, hence, are used to assist in decision-making on certain issues. The system formed by Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), a typical and economically important Brazilian Cerrado tree species, and its several arthropods are adequate to evaluate a new index. This study aimed to test an index to identify the loss and solution sources and their importance in the system's loss or income gain. The index is: Percentage of Importance Indice % I . I . = k s 1 × c 1 × d s 1 / Σ k s 1 × c 1 × d s 1 + k s 2 × c 2 × d s 2 + k s n × c n × d s n x 100. T h e % I . I . separated the loss sources [e.g., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) on fruits = 41.90%)] on the percentage of reduction of fruit production (e.g., 0.13%), calculated the attention level (e.g., 0.10/fruit), with a total lost production of 1.35% (≈ 307 total lost fruits). The % I.I. also separated the solution sources [e.g., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55.48%), the non-attention level (e.g., Z. armillatus: 0.394 for E. rufomarginata on fruit), with total income gain of 0.56% (≈ 128 total saved fruits) on the natural system (e.g., C. brasiliense trees). This index can calculate losses or the effectiveness of the solutions monetarily. Here I test the % I.I., an index that can detect the key loss and solution sources on the system, which can be applied in some knowledge areas.


Resumo Frequências, magnitudes e distribuição de ocorrência pode afetar os eventos. O problema pode ser pior ou a solução melhor se maiores frequências e magnitudes forem apresentadas com distribuição agregada no sistema de produção. Índices, então, são usados para assistir na decisão de certas questões. O sistema formado pelo Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), uma espécie arbórea típica e economicamente importante do Cerrado brasileiro, e seus diversos artrópodes são adequados para avaliar um novo índice. A motivação deste trabalho foi testar um índice capaz de identificar as fontes de perda e de soluções, e suas importâncias em termos de perdas ou ganhos no sistema. O índice é: percentagem de importância % I . I . = k s 1 × c 1 × d s 1 / Σ k s 1 × c 1 × d s 1 + k s 2 × c 2 × d s 2 + k s n × c n × d s n x 100. O % I . I . separou as fontes de perda [ex., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) em frutos = 41,90%)] na percentagem de redução na produção de frutos (ex., 0,13%), calculando o nível de atenção (ex., 0,10/fruto), com um total de perda de produção de 1,35% (≈ 307 frutos totais perdidos). O % I.I. também separou as fontes de solução [ex., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55,48%)], o nível de não atenção (ex., Z. armillatus: 0,394 para E. rufomarginata em fruto), com total de ganho de 0,56% (≈ 128 total de frutos salvos) no sistema natural (ex., árvores de C. brasiliense). Esse índice pode calcular essas perdas ou a eficácia das soluções monetariamente. Aqui eu testo o % I.I., um índice capaz de detectar fatores chaves de perda e de soluções no sistema, capaz de ser aplicado em algumas áreas do conhecimento.

2.
Braz. j. biol ; 84: e253218, 2024. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1355863

RESUMO

Abstract Indices are used to help on decision-making. This study aims to develop and test an index, which can determine the loss (e.g., herbivorous insects) and solution (e.g., natural enemies) sources. They will be classified according to their importance regarding the ability to damage or to reduce the source of damage to the system when the final production is unknown. Acacia auriculiformis (Fabales: Fabaceae), a non-native pioneer species in Brazil with fast growth and rusticity, is used in restoration programs, and it is adequate to evaluate a new index. The formula was: Percentage of the Importance Indice-Production Unknown (% I.I.-PU) = [(ks1 x c1 x ds1)/Σ (ks1 x c1 x ds1) + (ks2 x c2 x ds2) + (ksn x cn x dsn)] x 100. The loss sources Aethalion reticulatum L., 1767 (Hemiptera: Aethalionidae), Aleyrodidae (Hemiptera), Stereoma anchoralis Lacordaire, 1848 (Coleoptera: Chrysomelidae), and Tettigoniidae, and solution sources Uspachus sp. (Araneae: Salticidae), Salticidae (Araneae), and Pseudomyrmex termitarius (Smith, 1877) (Hymenoptera: Formicidae) showed the highest % I.I.-PU on leaves of A. auriculiformis saplings. The number of Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae) was reduced per number of Salticidae; that of A. reticulatum that of Uspachus sp.; and that of Cephalocoema sp. (Orthoptera: Proscopiidae) that of P. termitarius on A. auriculiformis saplings. However, the number of Aleyrodidae was increased per number of Cephalotes sp. (Hymenoptera: Formicidae) and that of A. reticulatum that of Brachymyrmex sp. (Hymenoptera: Formicidae) on A. auriculiformis saplings. The A. reticulatum damage was reduced per number of Uspachus sp., but the Aleyrodidae damage was increased per number of Cephalotes sp., totaling 23.81% of increase by insect damages on A. auriculiformis saplings. Here I show and test the % I.I.-PU. It is an new index that can detect the loss or solution sources on a system when production is unknown. It can be applied in some knowledge areas.


Resumo Índices são usados para ajudar na tomada de decisões. Este trabalho teve como objetivo desenvolver e testar um índice capaz de determinar fontes de perda (ex.: insetos herbívoros) e de solução (ex.: inimigos naturais). Eles serão classificados de acordo com sua importância quanto a habilidade de danificar ou reduzir danos no sistema, quando a produção final é desconhecida. Acacia auriculiformis (Fabales: Fabaceae), uma espécie pioneira não nativa do Brasil com rápido crescimento e rusticidade, usada em programas de restauração, é adequada para avaliar um novo índice. A fórmula foi: Porcentagem de Índice de Importância-Produção Desconhecida (% I.I.-PD) = [(ks1 x c1 x ds1)/Σ (ks1 x c1 x ds1) + (ks2 x c2 x ds2) + (ksn x cn x dsn)] x 100. As fontes de perda Aethalion reticulatum L., 1767 (Hemiptera: Aethalionidae), Aleyrodidae (Hemiptera), Stereoma anchoralis Lacordaire, 1848 (Coleoptera: Chrysomelidae) e Tettigoniidae, e as fontes de solução Uspachus sp. (Araneae: Salticidae), Salticidae (Araneae) e Pseudomyrmex termitarius (Smith, 1877) (Hymenoptera: Formicidae) apresentaram maiores % I.I.-PD nas folhas das mudas de A. auriculiformis. O número de Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae) foi reduzido pelo número de Salticidae; o de A. reticulatum pelo de Uspachus sp.; e o de Cephalocoema sp. (Orthoptera: Proscopiidae) pelo de P. termitarius em mudas de A. auriculiformis. Entretanto, o número de Aleyrodidae foi aumentado pelo número de Cephalotes sp. (Hymenoptera: Formicidae) e o de A. reticulatum pelo de Brachymyrmex sp. (Hymenoptera: Formicidae) em mudas de A. auriculiformis. O dano de A. reticulatum foi reduzido pelo número de Uspachus sp., mas o dano de Aleyrodidae foi aumentado pelo número de Cephalotes sp., totalizando 23,81% de aumento de danos em mudas de A. auriculiformis. Aqui eu apresento e testo o % I.I.-PD. Ele é um novo índice capaz de detectar fontes de perda e de solução no sistema quando não se conhece a produção final. Ele pode ser aplicado em algumas áreas do conhecimento.


Assuntos
Animais , Formigas , Besouros , Acacia , Hemípteros , Insetos
3.
Comput Methods Programs Biomed ; 225: 107040, 2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35932723

RESUMO

BACKGROUND AND OBJECTIVE: Dermatological images are typically diagnosed based on visual analysis of the skin lesion acquired using a dermoscope. However, the final quality of the acquired image is highly dependent on the illumination conditions during the acquisition phase. This variability in the light source can affect the dermatologist's diagnosis and decrease the accuracy of computer-aided diagnosis systems. Color constancy algorithms have proven to be a powerful tool to address this issue by allowing the standardization of the image illumination source, but the most commonly used algorithms still present some inherent limitations due to assumptions made on the original image. In this work, we propose a novel Dermatological Color Constancy Generative Adversarial Network (DermoCC-GAN) algorithm to overcome the current limitations by formulating the color constancy task as an image-to-image translation problem. METHODS: A generative adversarial network was trained with a custom heuristic algorithm that performs well on the training set. The model hence learns the domain transfer task (from original to color standardized image) and is then able to accurately apply the color constancy on test images characterized by different illumination conditions. RESULTS: The proposed algorithm outperforms state-of-the-art color constancy algorithms for dermatological images in terms of normalized median intensity and when using the color-normalized images in a deep learning framework for lesion classification (accuracy of the seven-class classifier: 79.2%) and segmentation (dice score: 90.9%). In addition, we validated the proposed approach on two different external datasets with highly satisfactory results. CONCLUSIONS: The novel strategy presented here shows how it is possible to generalize a heuristic method for color constancy for dermatological image analysis by training a GAN. The overall approach presented here can be easily extended to numerous other applications.

4.
Dev Sci ; : e13306, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35943256

RESUMO

When the illumination falling on a surface changes, so does the reflected light. Despite this, adult observers are good at perceiving surfaces as relatively unchanging - an ability termed colour constancy. Very few studies have investigated colour constancy in infants, and even fewer in children. Here we asked whether there is a difference in colour constancy between children and adults; what the developmental trajectory is between six and 11 years; and whether the pattern of constancy across illuminations and reflectances differs between adults and children. To this end, we developed a novel, child-friendly computer-based object selection task. In this, observers saw a dragon's favourite sweet under a neutral illumination and picked the matching sweet from an array of eight seen under a different illumination (blue, yellow, red, or green). This set contained a reflectance match (colour constant; perfect performance) and a tristimulus match (colour inconstant). We ran two experiments, with two-dimensional scenes in one and three-dimensional renderings in the other. Twenty-six adults and 33 children took part in the first experiment; 26 adults and 40 children took part in the second. Children performed better than adults on this task, and their performance decreased with age in both experiments. We found differences across illuminations and sweets, but a similar pattern across both age groups. This unexpected finding might reflect a real decrease in colour constancy from childhood to adulthood, explained by developmental changes in the perceptual and cognitive mechanisms underpinning colour constancy, or differences in task strategies between children and adults. This article is protected by copyright. All rights reserved.

5.
Am J Bot ; 2022 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-35844034

RESUMO

PREMISE: Honeybees dominate the flower-visitor assemblages of many plant species, yet their efficiency in terms of the quality of pollen delivered to stigmas is largely unknown. We investigated why honeybees are poor pollinators of Aloe ferox, a self-incompatible succulent treelet with large numbers of flowers. Honeybees are very frequent visitors to flowers of this species, yet contribute very little to seed production. METHODS: We assessed pollen loads on honeybees, studied their visitation behavior, selectively excluded birds from plants to determine direct effects of bees on pollen deposition, seed set and ovule abortion, and used a novel "split-pollinator" method to test whether honeybees deposit mainly low-quality self pollen. For the latter, we captured honeybees and with their existing pollen loads used them to either pollinate virgin flowers on the plant on which they were caught or to pollinate virgin flowers on different plants. KEY RESULTS: Honeybees cumulatively deposit as much pollen on stigmas as do birds, but our experiments showed that the pollen deposited by honeybees is mostly low quality self pollen that leads to substantial ovule discounting and depressed seed set. CONCLUSIONS: Lack of movement among A. ferox plants during individual honeybee foraging bouts is the most likely explanation for their deposition of low quality self pollen on stigmas. The "split-pollinator" method is a simple and cost-effective technique to test the quality of pollination. This article is protected by copyright. All rights reserved.

6.
Vision (Basel) ; 6(3)2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35893757

RESUMO

Several studies have shown the presence of large anisotropies for tactile distance perception across several parts of the body. The tactile distance between two touches on the dorsum of the hand is perceived as larger when they are oriented mediolaterally (across the hand) than proximodistally (along the hand). This effect can be partially explained by the characteristics of primary somatosensory cortex representations. However, this phenomenon is significantly attenuated relative to differences in acuity and cortical magnification, suggesting a process of tactile size constancy. It is unknown whether the same kind of compensation also takes place when estimating the size of a continuous object. Here, we investigate whether the tactile anisotropy that typically emerges when participants have to estimate the distance between two touches is also present when a continuous object touches the skin and participants have to estimate its size. In separate blocks, participants judged which of two tactile distances or objects on the dorsum of their hand felt larger. One stimulation (first or second) was aligned with the proximodistal axis (along the hand) and the other with the mediolateral axis (across the hand). Results showed a clear anisotropy for distances between two distinct points, with across distances consistently perceived as larger than along distances, as in previous studies. Critically, however, this bias was significantly reduced or absent for judgments of the length of continuous objects. These results suggest that a tactile size constancy process is more effective when the tactile size of an object has to be approximated compared to when the distance between two touches has to be determined. The possible mechanism subserving these results is described and discussed. We suggest that a lateral inhibition mechanism, when an object touches the skin, provides information through the distribution of the inhibitory subfields of the RF about the shape of the tactile RF itself. Such a process allows an effective tactile size compensatory mechanism where a good match between the physical and perceptual dimensions of the object is achieved.

7.
Vision (Basel) ; 6(3)2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35893761

RESUMO

We tested if the misapplication of perceptual constancy mechanisms might explain the perceived misalignment of the oblique lines in the Poggendorff illusion. Specifically, whether these mechanisms might treat the rectangle in the middle portion of the Poggendorff stimulus as an occluder in front of one long line appearing on either side, causing an apparent decrease in the rectangle's width and an apparent increase in the misalignment of the oblique lines. The study aimed to examine these possibilities by examining the effects of adding pictorial depth cues. In experiments 1 and 2, we presented a central rectangle composed of either large or small bricks to determine if this manipulation would change the perceived alignment of the oblique lines and the perceived width of the central rectangle, respectively. The experiments demonstrated no changes that would support a misapplication of perceptual constancy in driving the illusion, despite some evidence of perceptual size rescaling of the central rectangle. In experiment 3, we presented Poggendorff stimuli in front and at the back of a corridor background rich in texture and linear perspective depth cues to determine if adding these cues would affect the Poggendorff illusion. The central rectangle was physically large and small when presented in front and at the back of the corridor, respectively. The strength of the Poggendorff illusion varied as a function of the physical size of the central rectangle, and, contrary to our predictions, the addition of pictorial depth cues in both the central rectangle and the background decreased rather than increased the strength of the illusion. The implications of these results with regards to different theories are discussed. It could be the case that the illusion depends on both low-level and cognitive mechanisms and that deleterious effects occur on the former when the latter ascribes more certainty to the oblique lines being the same line receding into the distance.

8.
Animals (Basel) ; 12(14)2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35883344

RESUMO

This study examined goldfishes' ability to recognize photographs of rotated 3D objects. Six goldfish were presented with color photographs of a plastic model turtle and frog at 0° in a two-alternative forced-choice task. Fish were tested with stimuli at 0°, 90°, 180°, and 270° rotated in the picture plane and two depth planes. All six fish performed significantly above chance at all orientations in the three rotation planes tested. There was no significant difference in performance as a function of aspect angle, which supported viewpoint independence. However, fish were significantly faster at 180° than at +/-90°, so there is also evidence for viewpoint-dependent representations. These fish subjects performed worse overall in the current study with 2D color photographs (M = 88.0%) than they did in our previous study with 3D versions of the same turtle and frog stimuli (M = 92.6%), although they performed significantly better than goldfish in our two past studies presented with black and white 2D stimuli (M = 67.6% and 69.0%). The fish may have relied on color as a salient cue. This study was a first attempt at examining picture-object recognition in fish. More work is needed to determine the conditions under which fish succeed at object constancy tasks, as well as whether they are capable of perceiving photographs as representations of real-world objects.

9.
BMC Med Res Methodol ; 22(1): 204, 2022 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-35879673

RESUMO

When designing a noninferiority (NI) study one of the most important steps is to set the noninferiority (NI) limit. The NI limit is an acceptable loss of efficacy for a new investigative treatment compared to an active control treatment - often standard care. The limit should be a value so small that the loss efficacy is clinically zero. An approach to the setting of a noninferiority limit such that an effect over placebo can be shown through an indirect comparison to placebo-controlled trials where the active control treatment was compared to placebo. In this context, the setting of the NI limit depends on three assumptions: assay sensitivity, bias minimisation, and the constancy assumption. The last assumption of constancy assumes the effect of the active control over placebo is constant. This paper aims to assess the constancy assumption in placebo-controlled trials. METHODS: 236 Cochrane reviews of placebo-controlled trials published in 2015-2016 were collected and used to assess the relation between the placebo, active treatment, and the standardised treatment different (SMD) with the time (year of publication). RESULTS: The analysis showed that both the size of the study and the treatment effect were associated with year of publication. The three main variables that affect the estimate of any future trial are the estimate from the meta-analysis of previous trials prior to the trial, the year difference in the meta-analysis, and the year of the trial conduction. The regression analysis showed that an increase of one unit in the point estimate of the historical meta-analysis would lead to an increase in the predicted estimate of future trial on the SMD scale by 0.88. This result suggests the final trial results are 12% smaller than that from the meta-analysis of trials until that point. CONCLUSION: The result of this study indicates that assuming constancy of the treatment difference between the active control and placebo can be questioned. It is therefore important to consider the effect of time in estimating the treatment response if indirect comparisons are being used as the basis of a NI limit.


Assuntos
Viés , Humanos
10.
Vision (Basel) ; 6(2)2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35737424

RESUMO

This discussion paper supplements our two theoretical contributions previously published in this journal on the geometric nature of visual space. We first show here how our Riemannian formulation explains the recent experimental finding (published in this special issue on size constancy) that, contrary to conclusions from past work, vergence does not affect perceived size. We then turn to afterimage experiments connected to that work. Beginning with the Taylor illusion, we explore how our proposed Riemannian visual-somatosensory-hippocampal association memory network accounts in the following way for perceptions that occur when afterimages are viewed in conjunction with body movement. The Riemannian metric incorporated in the association memory network accurately emulates the warping of 3D visual space that is intrinsically introduced by the eye. The network thus accurately anticipates the change in size of retinal images of objects with a change in Euclidean distance between the egocentre and the object. An object will only be perceived to change in size when there is a difference between the actual size of its image on the retina and the anticipated size of that image provided by the network. This provides a central mechanism for size constancy. If the retinal image is the afterimage of a body part, typically a hand, and that hand moves relative to the egocentre, the afterimage remains constant but the proprioceptive signals change to give the new hand position. When the network gives the anticipated size of the hand at its new position this no longer matches the fixed afterimage, hence a size-change illusion occurs.

11.
Vision (Basel) ; 6(2)2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35645377

RESUMO

A prerequisite for efficient prehension is the ability to estimate an object's distance and size. While most studies demonstrate that binocular viewing is associated with a more efficient grasp programming and execution compared to monocular viewing, the factors contributing to this advantage are not fully understood. Here, we examined how binocular vision facilitates grasp scaling using two tasks: prehension and manual size estimation. Participants (n = 30) were asked to either reach and grasp an object or to provide an estimate of an object's size using their thumb and index finger. The objects were cylinders with a diameter of 0.5, 1.0, or 1.5 cm placed at three distances along the midline (40, 42, or 44 cm). Results from a linear regression analysis relating grip aperture to object size revealed that grip scaling during monocular viewing was reduced similarly for both grasping and estimation tasks. Additional analysis revealed that participants adopted a larger safety margin for grasping during monocular compared to binocular viewing, suggesting that monocular depth cues do not provide sufficient information about an object's properties, which consequently leads to a less efficient grasp execution.

13.
Front Hum Neurosci ; 16: 849159, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35547197

RESUMO

It is known that the human brain has a strong preference for rectangularity in interpreting pictures as 3D shapes. Symmetry is also considered to be a factor that the human vision system places high priority on when perceiving 3D objects. Thus, a question is raised: which is more basic, the rectangularity preference or the symmetry preference? To answer this question, we carried out experiments using pictures that have at least two interpretations as 3D objects, one of which was rectangular but not symmetric, and the other of which was symmetric but not rectangular. We found that the preference for rectangularity is stronger than that for symmetry. This observation will help us to understand various 3D optical illusions, including the room-size illusion and the ambiguous object illusion.

14.
Ecol Evol ; 12(4): e8847, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35462980

RESUMO

Pollinator behavior is an important contributor to plants speciation, yet how variation in pollinator behavior causes variation in reproductive isolation (RI) is largely uncharacterized. Here I present a model that predicts how two aspects of pollinator behavior, constancy and preference, contribute to a barrier to reproduction in plants. This model is motivated by two observations: most co-occurring plants vary in frequency over space and time, and most plants have multiple pollinators that differ in behavior. Thus, my goal was to understand how relative frequencies of plants and pollinators in a community influence ethological RI between co-occurring plants. I find that RI for a focal plant generally increases with increasing relative plant frequency, but the shape of this relationship is highly dependent on the strength of pollinator behavior (constancy and preference). Additionally, when multiple pollinators express different behavior, I find that pollinators with stronger preference disproportionately influence RI. But, I show that RI caused by constancy is the average RI predicted from constancy of each pollinator weighted by pollinator frequency. I apply this model to examples of pollinator-mediated RI in Phlox and in Ipomopsis to predict the relationships between plant frequency and ethological RI in natural systems. This model provides new insights into how and why pollinator specialization causes RI, and how RI could change with changing biological communities.

15.
Front Neurorobot ; 16: 841426, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464675

RESUMO

In obtaining color constancy, estimating the illumination of a scene is the most important task. However, due to unknown light sources and the influence of the external imaging environment, the estimated illumination is prone to color ambiguity. In this article, a learning-based multi-scale region-weighed network guided by semantic features is proposed to estimate the illuminated color of the light source in a scene. Cued by the human brain's processing of color constancy, we use image semantics and scale information to guide the process of illumination estimation. First, we put the image and its semantics into the network, and then obtain the region weights of the image at different scales. After that, through a special weight-pooling layer (WPL), the illumination on each scale is estimated. The final illumination is calculated by weighting each scale. The results of extensive experiments on Color Checker and NUS 8-Camera datasets show that the proposed approach is superior to the current state-of-the-art methods in both efficiency and effectiveness.

16.
Ecol Evol ; 12(3): e8697, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35342566

RESUMO

So far, oil-rewarding flowers are known to be pollinated only by oil-collecting bees, which gather and use lipids for larval feed and nest building. As honeybees do not have oil-collecting appendages on their legs, they have not been associated with pollination of such flowers. In a predominantly Apis pollinated and food deceptive clade of wild Cymbidiums, we investigated the reproductive strategy of Cymbidium aloifolium, hitherto unknown for its floral oil reward. Our study demonstrates the requisites for establishment of mutualistic interaction between the oil flower and Apis cerana indica, a corbiculate bee. Success in pollination requires learning by honeybees to access the food reward, thereby displaying cognitive ability of the pollinator to access the customized reward. Morphometric matching between orchid flowers and the pollinator, and that between pollinia and stigmatic cavity also appear to be essential in the pollination success. Absence of pollinator competition and prolonged flower-handling time are suggested to promote floral constancy. The present study highlights the need to explore the spectrum of pollination rewards pursued by honeybees, which may include unconventional composition of floral resources.

17.
Neuroimage ; 251: 119021, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35192941

RESUMO

Object constancy is one of the most crucial mechanisms of the human visual system enabling viewpoint invariant object recognition. However, the neuronal foundations of object constancy are widely unknown. Research has shown that the ventral visual stream is involved in processing of various kinds of object stimuli and that several regions along the ventral stream are possibly sensitive to the orientation of an object in space. To systematically address the question of viewpoint sensitive object perception, we conducted a study with stroke patients as well as an fMRI experiment with healthy participants applying object stimuli in several spatial orientations, for example in typical and atypical viewing conditions. In the fMRI experiment, we found stronger BOLD signals and above-chance classification accuracies for objects presented in atypical viewing conditions in fusiform face sensitive and lateral occipito-temporal object preferring areas. In the behavioral patient study, we observed that lesions of the right fusiform gyrus were associated with lower performance in object recognition for atypical views. The complementary results from both experiments emphasize the contributions of fusiform and lateral-occipital areas to visual object constancy and indicate that visual object constancy is particularly enabled through increased neuronal activity and specific activation patterns for objects in demanding viewing conditions.


Assuntos
Lobo Occipital , Percepção Visual , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Lobo Occipital/diagnóstico por imagem , Lobo Occipital/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiologia , Percepção Visual/fisiologia
18.
Eur J Protistol ; 82: 125844, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34973632

RESUMO

The spatial and temporal planktonic ciliate community structure of a large shallow eutrophic lake was described in detail based on a monthly monitoring campaign over 2 years using the quantitative protargol stain approach. We found that there was a large variety and low constancy of ciliate plankton and a clear advantage of several small species. Balanion planctonicum, Rimostrombidium brachykinetum, and Urotricha farcta contributed 19.7%, 13.4%, and 10.7% to the total abundance, respectively. The ciliate community was significantly varied in different lake regions of different eutrophication levels, and the distribution of some of the main species, especially prostomatids and scuticociliatids, might be closely related to the nutrient level of the lake regions. The seasonal dynamics of ciliate taxa with similar functional feeding habits across regions at different trophic levels are more convergent than those of species with very different functions, and the top-down effect (cladocerans, rotifers), nutrition, and water temperature were the key factors shaping ciliate community structure. The results of this study accentuate the important effects of species functional diversity on community differences and may improve our knowledge of ciliate diversity and functional ecology in shallow eutrophic lakes.


Assuntos
Cilióforos , Lagos , China , Eutrofização , Plâncton
19.
Proc Biol Sci ; 289(1967): 20212483, 2022 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-35078360

RESUMO

Colour constancy refers to the constant perceived or apparent colour of a surface despite changes in illumination spectrum. Laboratory measurements have often found it imperfect. The aim here was to estimate the frequency of constancy failures in natural outdoor environments and relate them to colorimetric surface properties. A computational analysis was performed with 50 hyperspectral reflectance images of outdoor scenes undergoing simulated daylight changes. For a chromatically adapted observer, estimated colour appearance changed noticeably for at least 5% of the surface area in 60% of scenes, and at least 10% of the surface area in 44% of scenes. Somewhat higher frequencies were found for estimated changes in perceived colour relations represented by spatial ratios of cone-photoreceptor excitations. These estimated changes correlated with surface chroma and saturation. Outdoors, the colour constancy of some individual surfaces seems likely to fail, particularly if those surfaces are colourful.


Assuntos
Percepção de Cores , Células Fotorreceptoras Retinianas Cones , Cor , Luz , Propriedades de Superfície
20.
SN Comput Sci ; 3(1): 22, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34778840

RESUMO

Virtual reality (VR) technology offers vision researchers the opportunity to conduct immersive studies in simulated real-world scenes. However, an accurate colour calibration of the VR head mounted display (HMD), both in terms of luminance and chromaticity, is required to precisely control the presented stimuli. Such a calibration presents significant new challenges, for example, due to the large field of view of the HMD, or the software implementation used for scene rendering, which might alter the colour appearance of objects. Here, we propose a framework for calibrating an HMD using an imaging colorimeter, the I29 (Radiant Vision Systems, Redmond, WA, USA). We examine two scenarios, both with and without using a rendering software for visualisation. In addition, we present a colour constancy experiment design for VR through a gaming engine software, Unreal Engine 4. The colours of the objects of study are chosen according to the previously defined calibration. Results show a high-colour constancy performance among participants, in agreement with recent studies performed on real-world scenarios. Our studies show that our methodology allows us to control and measure the colours presented in the HMD, effectively enabling the use of VR technology for colour vision research.

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