Bark reflectance spectra of conifers and angiosperms: implications for host discrimination by coniferophagous bark and timber beetles

2005 ◽  
Vol 137 (6) ◽  
pp. 719-722 ◽  
Author(s):  
Stuart A. Campbell ◽  
John H. Borden
Keyword(s):  
Visual System ◽  
Spectral Reflectance ◽  
Visual Cues ◽  
Host Plants ◽  
Green Light ◽  
Phytophagous Insects ◽  
Host Discrimination ◽  
Environmental Light ◽  
Reflected Light ◽  
Uv Reflectance

The spectral reflectance of phytophagous insects' host plants is usually quantified between 300–350 nm (ultraviolet, UV) and 700 nm (farred to infrared), and the shape and magnitude of the distribution of reflected light determine the hue, saturation, and intensity perceived by insects (Moericke 1969). Host perception also depends on the distribution of environmental light (Endler 1993) and on the constraints of the insects' visual system, which is usually described as dichromatic, with one type of photoreceptor responding maximally to blue light (λmax = ca. 400–470 nm) and another to green light (λmax = ca. 500–530 nm). UV receptors also appear to be common, if not ubiquitous (Briscoe and Chittka 2001; Mazza et al. 2002). Several phytophagous insects have been shown to use visual cues, including UV reflectance, to locate and (or) discriminate among plants (Prokopy and Owens 1983).

The role of vision on postural strategy evaluated in patients affected by congenital nystagmus as an experimental model

1999 ◽  
Vol 9 (6) ◽  
pp. 445-451
Author(s):  
S. Di Girolamo ◽  
W. Di Nardo ◽  
A. Cosenza ◽  
F. Ottaviani ◽  
A. Dickmann ◽  
...  
Keyword(s):  
Visual System ◽  
Postural Control ◽  
Visual Stimulus ◽  
Postural Balance ◽  
Visual Cues ◽  
Normal Subjects ◽  
Congenital Nystagmus ◽  
Dynamic Posturography ◽  
Normal Controls

The role of vision in postural control is crucial and is strictly related to the characteristics of the visual stimulus and to the performance of the visual system. The purpose of this investigation was to evaluate the effects of chronically reduced visual cues upon postural control in patients affected by Congenital Nystagmus (CN). These patients have developed since birth a postural strategy mainly based on vestibular and somatosensorial cues. Fifteen patients affected by CN and 15 normal controls (NC) were enrolled in the study and evaluated by means of dynamic posturography. The overall postural control in CN patients was impaired as demonstrated by the equilibrium score and by the changes of the postural strategy. This impairment was even more enhanced in CN than in NC group when somatosensorial cues were experimentally reduced. An aspecific pattern of visual impairment and a pathological composite score were also present. Our data outline that in patients affected by CN an impairment of the postural balance is present especially when the postural control relies mainly on visual cues. Moreover, a decrease in accuracy of the somatosensory cues has a proportionally greater effect on balance than it has on normal subjects.

scholarly journals Phototaxis in a wild isolate of the cyanobacterium Synechococcus elongatus

2018 ◽  
Vol 115 (52) ◽  
pp. E12378-E12387 ◽  
Author(s):  
Yiling Yang ◽  
Vinson Lam ◽  
Marie Adomako ◽  
Ryan Simkovsky ◽  
Annik Jakob ◽  
...  
Keyword(s):  
Energy Source ◽  
Metabolic Engineering ◽  
Circadian Rhythms ◽  
Green Light ◽  
Synechococcus Elongatus ◽  
Negative Phototaxis ◽  
Wild Isolate ◽  
Environmental Light ◽  
Light Signals ◽  
Pcc 7942

Many cyanobacteria, which use light as an energy source via photosynthesis, have evolved the ability to guide their movement toward or away from a light source. This process, termed “phototaxis,” enables organisms to localize in optimal light environments for improved growth and fitness. Mechanisms of phototaxis have been studied in the coccoid cyanobacterium Synechocystis sp. strain PCC 6803, but the rod-shaped Synechococcus elongatus PCC 7942, studied for circadian rhythms and metabolic engineering, has no phototactic motility. In this study we report a recent environmental isolate of S. elongatus, the strain UTEX 3055, whose genome is 98.5% identical to that of PCC 7942 but which is motile and phototactic. A six-gene operon encoding chemotaxis-like proteins was confirmed to be involved in phototaxis. Environmental light signals are perceived by a cyanobacteriochrome, PixJSe (Synpcc7942_0858), which carries five GAF domains that are responsive to blue/green light and resemble those of PixJ from Synechocystis. Plate-based phototaxis assays indicate that UTEX 3055 uses PixJSe to sense blue and green light. Mutation of conserved functional cysteine residues in different GAF domains indicates that PixJSe controls both positive and negative phototaxis, in contrast to the multiple proteins that are employed for implementing bidirectional phototaxis in Synechocystis.

scholarly journals PICTURES OF ME: POSSIBILITIES OF SHAPING OUR BODY IMAGE THROUGH VIRTUAL REALITY / MANO PORTRETAI: KŪNO ATVAIZDŲ APIFORMINIMO GALIMYBĖS VIRTUALIOJOJE REALYBĖJE

2012 ◽  
Vol 5 (1) ◽  
pp. 1-10
Author(s):  
Mateusz Woźniak
Keyword(s):  
Body Image ◽  
Virtual Reality ◽  
Visual Perception ◽  
Visual System ◽  
Visual Cues ◽  
Virtual Space ◽  
Brain System ◽  
Adaptive Representation ◽  
Sensory Motor ◽  
Human Embodiment

Brain system responsible for visual perception has been extensively studied. Visual system analyses a wide variety of stimuli in order to let us create adaptive representation of surrounding world. But among vast amounts of processed information come visual cues describing our own bodies. These cues constitute our so-called body-image. We tend to perceive it as a relatively stable structure but recent research, especially within the domain of virtual reality, introduces doubts to this assumption. New problems appear concerning perceiving others’ and our own bodies in virtual space and how does it influence our experience of ourselves and true reality. Recent studies show that how we see our avatars influence how we behave in artificial worlds. It introduces a brand new way of thinking about human embodiment. Virtual reality allows us to transcend beyond the casual visual-sensory-motor integration and create new ways to experience embodiment, temporarily replacing permanent body image with almost any imaginable digital one. Santrauka Smegenų sistema, atsakinga už vizualųjį suvokimą, yra nuodugniai ištirta. Vizualioji sistema analizuoja plačią akstinų įvairovę, padedančią mums sukurti adaptuotą supančio pasaulio reprezentaciją. Tačiau tarp didelio kiekio apdorotos informacijos kyla vizualiosios užuominos, atvaizduojančios mūsų pačių kūnus. Šios užuominos steigia vadinamąjį kūną-atvaizdą. Mes linkstame jį suvokti kaip sąlygiškai stabilią struktūrą, tačiau dabartiniai tyrimai, o ypač tie, kurie vykdomi virtualiojoje realybėje, tokia prielaida verčia suabejoti. Kyla naujų problemų, suvokiant kitų ir mūsų pačių kūnus virtualiojoje erdvėje bei kokios įtakos tai turi mūsų pačių savęs ir tikrosios realybės patyrimui. Nūdieniai tyrinėjimai atskleidžia, kad tai, kaip mes suvokiame savąjį kūniškumą, turi įtakos tam, kaip elgiamės dirbtiniuose pasauliuose. Tai steigia visiškai naują žmogiškojo kūniškumo suvokimo būdą. Virtualioji realybė leidžia mums peržengti paprastą vizualinęjutiminę-motorinę integraciją ir kurti naujus būdus patirti kūniškumą, palaipsniui pakeičiant ilgalaikį kūno atvaizdą bet kokiu įsivaizduojamu skaitmeniniu.

The Effect of Peripheral Visual Cues on the Control of Self-Stabilization in Roll

1993 ◽  
Vol 37 (1) ◽  
pp. 157-161 ◽  
Author(s):  
Melanie R. James ◽  
Jon N. Coldwell ◽  
Andrew J. Belyavin
Keyword(s):  
Visual System ◽  
Visual Cues ◽  
Likelihood Estimation ◽  
Laboratory Research ◽  
Velocity Control ◽  
Random Forcing ◽  
Forcing Function ◽  
Rms Error ◽  
Self Stabilization ◽  
Continuous Source

This paper reports a programme of laboratory research to assess the potential of a new form of aircraft attitude indicator. The Ambient Attitude Indicator (AAI), designed to exploit the characteristics of the ambient visual system, provides a continuous source of world-stabilized orientation information to the pilot's ambient visual system. In laboratory experiments, the first of which is reported here, the effects of peripheral visual cues on subjects' control of continuous self-stabilization in roll are assessed. Subjects, seated on a roll turntable, were required to null a continuous quasi-random forcing function using a velocity-control joystick. Their objective was to maintain a stable upright orientation. Three visual conditions were studied: no visual cues, world-stabilized peripheral visual cues, and turntable-stabilized peripheral visual cues. Significant effects of visual condition were found for measures of joystick RMS displacement, turntable RMS error, and frequency of changes of direction of the turntable. World-stabilized conditions resulted in the highest joystick RMS displacement, the lowest turntable RMS error, and the highest frequency of changes of direction of the turntable. A linear transfer function, with autoregressive noise process to represent the remnant, was fitted to the data using maximum likelihood estimation. Details of subjects' frequency response are presented and the effects of practice on these measures are also considered.

scholarly journals Phytophagous Insects on Native and Non-Native Host Plants: Combining the Community Approach and the Biogeographical Approach

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0125607 ◽  
Author(s):  
Kim Meijer ◽  
Hidde Zemel ◽  
Satoshi Chiba ◽  
Christian Smit ◽  
Leo W. Beukeboom ◽  
...  
Keyword(s):  
Host Plants ◽  
Phytophagous Insects ◽  
Community Approach ◽  
Native Host

Simplified field measurement methods for the CIE mesopic photometry system

2016 ◽  
Vol 49 (6) ◽  
pp. 774-787 ◽  
Author(s):  
T Uchida ◽  
Y Ohno
Keyword(s):  
Light Source ◽  
Spectral Reflectance ◽  
Spectral Power ◽  
Road Surface ◽  
Worst Case ◽  
Distribution Method ◽  
The Road ◽  
Reflected Light ◽  
Test Points ◽  
Adaptation Field

For implementation of the mesopic photometry system in CIE 191:2010 to outdoor lighting, two simplified methods to measure the mesopic luminance are proposed. One of the methods, named the Adaptation Spectral Power Distribution) method, assumes that the spectral power distributions (SPDs) of reflected light at test points on the road surface are the same as that of the adaptation field. Another method, named the Source SPD method, assumes that the reflected light SPDs are equal to the SPD of the light source. Error simulations with a real road surface spectral reflectance dataset show that the error distributes over an 8% range due to the variation of the road surface spectral reflectance in the worst case. Although the bias due to the road surface spectral reflectances causes a large error with the Source SPD method, a proposed correction can reduce the error sufficiently. Error simulations also show that the Source SPD method is not so sensitive for lighting scenes that include multiple light source types. It has been shown that the SPD methods can measure the mesopic quantities without scotopic/photopic luminance meters having both V( λ) and V′( λ) detectors when both the adaptation field and test points consist of road surfaces.

The Role of Host Selection in the Ecology of Phytophagous Insects

1953 ◽  
Vol 85 (8) ◽  
pp. 276-282 ◽  
Author(s):  
A. J. Thorsteinson
Keyword(s):  
Host Plant ◽  
Host Selection ◽  
Host Plants ◽  
Host Plant Selection ◽  
Phytophagous Insects ◽  
Phytophagous Insect ◽  
Ecological Significance ◽  
Plant Selection ◽  
Suitable Host

It is a commonplace entomological observation that each phytophagous insect is restricted in its feeding to a small fraction only of the plant species that grow in any area. This phenomenon is generally referred to as “host selection”. The ecological significance of host plant selection among insects is manifest principally in an effect on the geographical distribution of insect species since phytophagous insects can occur only where suitable host plants are available.

Characteristics of Visual Fidelity in the Virtual Environment

1996 ◽  
Vol 5 (3) ◽  
pp. 330-345 ◽  
Author(s):  
Edward J. Rinalducci
Keyword(s):  
Visual System ◽  
Virtual Environments ◽  
Virtual Environment ◽  
Spatial Resolution ◽  
Visual Cues ◽  
Field Of View ◽  
Visual Characteristics ◽  
The Creation ◽  
Vertical Development ◽  
Visual Fidelity

This paper provides an overview of the literature on the visual system, placing special emphasis on those visual characteristics regarded as necessary to produce adequate visual fidelity in virtual environments. These visual cues apply to the creation of various virtual environments including those involving flying, driving, sailing, or walking. A variety of cues are examined, in particular, motion, color, stereopsis, pictorial and secondary cues, physiological cues, texture, vertical development, luminance, field-of-view, and spatial resolution. Conclusions and recommendations for research are also presented.

scholarly journals Learning may help pollinators find their host plants in polluted landscapes

2019 ◽  
Author(s):  
Brynn Cook ◽  
Alexander Haverkamp ◽  
Bill S. Hansson ◽  
T’ai Roulston ◽  
Manuel Lerdau ◽  
...  
Keyword(s):  
Food Production ◽  
Visual Cues ◽  
Host Plants ◽  
Ozone Exposure ◽  
Nicotiana Alata ◽  
Elevated Ozone ◽  
Pollinating Insects ◽  
The Impact ◽  
Plant Pollinator ◽  
Ozone Levels

AbstractPollination strongly contributes to food production, and often relies on pollinating insects. However, atmospheric pollution may interfere with pollination by disrupting floral plumes that pollinators use to navigate to flowers.In this study, we examine the impacts of pollution-induced elevated ozone levels on the composition of a floral blend of Nicotiana alata and examine the response of innate and trained Manduca sexta to the ozone-altered blend.Ozone exposure altered the floral blend of N. alata, and disrupted the innate attraction of naïve M. sexta to the altered blend. However, associative learning can offset this disruption in attraction. Moths that were enticed with visual cues to an artificial flower emitting an ozonated blend learned to associate this blend with a nectar reward after just one rewarded experience. More importantly, moths that were rewarded while experiencing the unozonated floral blend of their host subsequently found the ozonated floral blend of the same host attractive, most likely due to experience-based reinforcement of ozone-insensitive cues in the blend.The attraction of moths to both unaltered and ozonated plumes is critical for tolerating polluted landscapes. At the host plant, where moths feed, floral emissions are relatively pure. As floral odors travel away from the host, however, they become degraded by pollution. Therefore, targeting the flower requires recognizing both conditions of the odor. The ability to generalize between the pure and ozone-altered scents may enable pollinators like M. sexta to maintain communication with their flowers and reduce the impact anthropogenic oxidants may have on plant-pollinator systems.

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