Structure of the Retinae of the Principal Eyes of Jumping Spiders (Salticidae: Dendryphantinae) in Relation to Visual Optics

1969 ◽  
Vol 51 (2) ◽  
pp. 443-470 ◽  
Author(s):  
M. F. LAND
Keyword(s):  
Spherical Aberration ◽  
Incident Light ◽  
Red Light ◽  
Green Light ◽  
Chromatic Aberration ◽  
Superficial Layer ◽  
Visual Optics ◽  
Jumping Spiders ◽  
Layer 2 ◽  
Layer 4

1. The retinae of the principal (AM) eyes of jumping spiders contain four layers of receptors, one behind the other with respect to the incident light. The distribution of receptors in each layer has been determined. 2. The deepest layers (1 and 2) cover the whole area of the retina, and have the greatest density of receptors. The minimum receptor separation is 1.7 µm., or 11 min. visual angle. The more superficial layers (3 and 4) are confined to the central region of the retina. 3. In layers 1, 2 and 3 the rhabdomere-containing segments are rod-shaped, and are parallel to the incident light. In layer 4 they are ovoid, and are oriented approximately at right angles to the light. 4. At the first optic glomerulus the primary fibres from each receptor layer appear to terminate in separate regions of neuropile. 5. The focal lengths, radii of curvature and refractive indices of the lenses of the principal and side eyes have been measured. For the principal eyes, estimates have also been made of the diffraction limit, the depth of focus, and the magnitudes of chromatic and spherical aberration. 6. The normal position of the image in the eye was found by ophthalmoscopy. For blue-green light, the best image of distant objects is formed on the next-to-deepest layer (2). 7. The deepest layer (1) is conjugate with a plane about 2 cm. in front of the animal for blue-green light, or with infinity for red light, because of the eye's chromatic aberration. 8. Two theories are offered to account for the retinal layering. Either the spider uses different layers to examine maximally sharp images of objects at different dis tances; or each layer exploits the sharpest image of distant objects, but for light of different wavelengths. 9. Optical considerations indicate that either theory is possible, but the seconds (wavelength) theory is the more probable, because jumping spiders are known to possess colour vision. It predicts that layer 1 receptors contain red-sensitive, layer 2 blue-green sensitive and layer 3 violet-ultraviolet Sensitive pigments. 10. The structural peculiarities of the most superficial layer (4), and the fact that it is not conjugate with any plane in front of the animal for any visible wavelength, suggest that it is not resolving an image, but performing some other function. Reasons are given for thinking that this might be the analysis of the pattern of polarization of skylight.

scholarly journals The influence of cortical depth on neuronal responses in mouse visual cortex

2018 ◽  
Author(s):  
Philip O’Herron ◽  
John Woodward ◽  
Prakash Kara
Keyword(s):  
Visual Cortex ◽  
Neuronal Response ◽  
Superficial Layer ◽  
Cortical Layer ◽  
Contrast Imaging ◽  
Response Properties ◽  
Layer 2 ◽  
Layer 4 ◽  
Thalamic Projections ◽  
Mouse Visual Cortex

AbstractWith the advent of two-photon imaging as a tool for systems neuroscience, the mouse has become a preeminent model system for studying sensory processing. One notable difference that has been found however, between mice and traditional model species like cats and primates is the responsiveness of the cortex. In the primary visual cortex of cats and primates, nearly all neurons respond to simple visual stimuli like drifting gratings. In contrast, imaging studies in mice consistently find that only around half of the neurons respond to such stimuli. Here we show that visual responsiveness is strongly dependent on the cortical depth of neurons. Moving from superficial layer 2 down to layer 4, the percentage of responsive neurons increases dramatically, ultimately reaching levels similar to what is seen in other species. Over this span of cortical depth, neuronal response amplitude also increases and orientation selectivity moderately decreases. These depth dependent response properties may be explained by the distribution of thalamic inputs in mouse V1. Unlike in cats and primates where thalamic projections to the granular layer are constrained to layer 4, in mice they spread up into layer 2/3, qualitatively matching the distribution of response properties we see. These results show that the analysis of neural response properties must take into consideration not only the overall cortical lamina boundaries but also the depth of recorded neurons within each cortical layer. Furthermore, the inability to drive the majority of neurons in superficial layer 2/3 of mouse V1 with grating stimuli indicates that there may be fundamental differences in the role of V1 between rodents and other mammals.

scholarly journals Effect of light quality and quantity on productivity and phycoerythrin concentration in the cryptophyte Rhodomonas sp.

2021 ◽  
Author(s):  
Christos Latsos ◽  
Jasper van Houcke ◽  
Lander Blommaert ◽  
Gabrielle P. Verbeeke ◽  
Jacco Kromkamp ◽  
...  
Keyword(s):  
Light Quality ◽  
Incident Light ◽  
Red Light ◽  
Green Light ◽  
Dry Weight ◽  
Continuous Illumination ◽  
Light Illumination ◽  
Initial Growth ◽  
Light Conditions ◽  
Significant Difference

AbstractThe cryptophyte Rhodomonas sp. is a potential feed source for aquaculture live feed and resource for phycoerythrin (PE) production. This research investigates the influence of light, both quality and quantity, on the biomass productivity, composition and growth rate of Rhodomonas sp. The incident light intensity used in the experiments was 50 μmolphotons m−2 s−1, irrespective of the colour of the light, and cultivation took place in lab-scale flat-panel photobioreactors in turbidostat mode. The highest productivity in volumetric biomass (0.20 gdry weight L−1 day−1), measured under continuous illumination, was observed under green light conditions. Blue and red light illumination resulted in lower productivities, 0.11 gdry weight L−1 day−1 and 0.02 g L−1 day−1 respectively. The differences in production are ascribed to increased absorption of green and blue wavelength by phycoerythrin, chlorophyll and carotenoids, causing higher photosynthetically usable radiation (PUR) from equal photosynthetically absorbed irradiance (PAR). Moreover, phycoerythrin concentration (281.16 mg gDW−1) was stimulated under red light illumination. Because photosystem II (PSII) absorbs poorly red light, the algae had to induce more pigments in order to negate the lower absorption per unit pigment of the incident available photons. The results of this study indicate that green light can be used in the initial growth of Rhodomonas sp. to produce more biomass and, at a later stage, red light could be implemented to stimulate the synthesis of PE. Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated a significant difference between the cells under different light quality, with higher contents of proteins for samples of Rhodomonas sp. cultivated under green light conditions. In comparison, higher carbohydrate contents were observed for cells that were grown under red and blue light.

scholarly journals Blue/green light-responsive cyanobacteriochromes are cell shade sensors in red-light replete niches

2019 ◽  
Author(s):  
Gen Enomoto ◽  
Masahiko Ikeuchi
Keyword(s):  
Cell Density ◽  
Blue Light ◽  
Hot Springs ◽  
Incident Light ◽  
Natural Habitat ◽  
Red Light ◽  
Green Light ◽  
Light Response ◽  
Cell Aggregation ◽  
Cell Position

SummaryPhotoautotrophic cyanobacteria have developed sophisticated light response systems to capture and utilize the energy and information of incident light [1]. Cyanobacteria-specific photoreceptors cyanobacteriochromes (CBCRs) are distantly related to more widespread phytochromes. CBCRs show the most diverse spectral properties among the naturally occurring photoreceptors, typified by a unique and prevailing blue/green light-absorbing variant [2–6]. However, where the CBCR-mediated ‘colorful’ signaling systems function in nature has been elusive. We previously reported that the three CBCRs SesA/B/C synthesize/degrade a bacterial second messenger cyclic diguanylate (c-di-GMP) in response to blue/green light [6–8]. The cooperative action of SesA/B/C enables blue light-ON and green light-OFF regulation of the c-di-GMP-dependent cell aggregation of the thermophilic cyanobacterium Thermosynechococcus vulcanus [8, 9]. Here, we report that SesA/B/C can serve as a physiological sensor of cell density. Because cyanobacterial cells show lower transmittance of blue light than green light, higher cell density gives more green light-enriched irradiance to cells. The cell density-dependent suppression of cell aggregation under blue/green-mixed light and white light conditions support this idea. Such a sensing mechanism may provide information about the cell position in cyanobacterial mats in hot springs, the natural habitat of Thermosynechococcus. This cell position-dependent SesA/B/C-mediated regulation of cellular sessility (aggregation) might be ecophysiologically essential for the reorganization and growth of phototrophic mats. We also report that the green light-induced dispersion of cell aggregates requires red light-driven photosynthesis. Blue/green CBCRs might work as shade detectors in a different niche than red/far-red phytochromes, which may be why CBCRs have evolved in cyanobacteria.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

Chromatic aberration and low-voltage SEM

1987 ◽  
Vol 45 ◽  
pp. 546-547
Author(s):  
Zhifeng Shao ◽  
A.V. Crewe
Keyword(s):  
Electron Energy ◽  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Primary Electron ◽  
Probe Size ◽  
Non Local ◽  
Optical Treatment ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

For scanning electron microscopes, it is plausible that by lowering the primary electron energy, one can decrease the volume of interaction and improve resolution. As shown by Crewe /1/, at V0 =5kV a 10Å resolution (including non-local effects) is possible. To achieve this, we would need a probe size about 5Å. However, at low voltages, the chromatic aberration becomes the major concern even for field emission sources. In this case, δV/V = 0.1 V/5kV = 2x10-5. As a rough estimate, it has been shown that /2/ the chromatic aberration δC should be less than ⅓ of δ0 the probe size determined by diffraction and spherical aberration in order to neglect its effect. But this did not take into account the distribution of electron energy. We will show that by using a wave optical treatment, the tolerance on the chromatic aberration is much larger than we expected.

Ultra-high resolution SEMI-in-lens type FE-SEM, JSM-6320F, with strong magnetic-field lens with built-in secondary-electron detector

1994 ◽  
Vol 52 ◽  
pp. 484-485
Author(s):  
T. Miyokawa ◽  
H. Kazumori ◽  
S. Nakagawa ◽  
C. Nielsen
Keyword(s):  
High Resolution ◽  
Secondary Electron ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Chromatic Aberration ◽  
Magnetic Flux Density ◽  
Objective Lens ◽  
Electron Detector ◽  
High Resolution Images ◽  
Working Distance

We have developed a strongly excited objective lens with a built-in secondary electron detector to provide ultra-high resolution images with high quality at low to medium accelerating voltages. The JSM-6320F is a scanning electron microscope (FE-SEM) equipped with this lens and an incident beam divergence angle control lens (ACL).The objective lens is so strongly excited as to have peak axial Magnetic flux density near the specimen surface (Fig. 1). Since the speciien is located below the objective lens, a large speciien can be accomodated. The working distance (WD) with respect to the accelerating voltage is limited due to the magnetic saturation of the lens (Fig.2). The aberrations of this lens are much smaller than those of a conventional one. The spherical aberration coefficient (Cs) is approximately 1/20 and the chromatic aberration coefficient (Cc) is 1/10. for accelerating voltages below 5kV. At the medium range of accelerating voltages (5∼15kV). Cs is 1/10 and Cc is 1/7. Typical values are Cs-1.lmm. Cc=l. 5mm at WD=2mm. and Cs=3.lmm. Cc=2.9 mm at WD=5mm. This makes the lens ideal for taking ultra-high resolution images at low to medium accelerating voltages.

Electron Holography Improving Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 208-209
Author(s):  
Hannes Lichte
Keyword(s):  
Electron Microscopy ◽  
Transfer Functions ◽  
Imaging System ◽  
Spherical Aberration ◽  
Image Plane ◽  
Chromatic Aberration ◽  
Object Wave ◽  
Objective Lens ◽  
Electron Holography ◽  
Wave Aberration

Generally, the electron object wave o(r) is modulated both in amplitude and phase. In the image plane of an ideal imaging system we would expect to find an image wave b(r) that is modulated in exactly the same way, i. e. b(r) =o(r). If, however, there are aberrations, the image wave instead reads as b(r) =o(r) * FT(WTF) i. e. the convolution of the object wave with the Fourier transform of the wave transfer function WTF . Taking into account chromatic aberration, illumination divergence and the wave aberration of the objective lens, one finds WTF(R) = Echrom(R)Ediv(R).exp(iX(R)) . The envelope functions Echrom(R) and Ediv(R) damp the image wave, whereas the effect of the wave aberration X(R) is to disorder amplitude and phase according to real and imaginary part of exp(iX(R)) , as is schematically sketched in fig. 1.Since in ordinary electron microscopy only the amplitude of the image wave can be recorded by the intensity of the image, the wave aberration has to be chosen such that the object component of interest (phase or amplitude) is directed into the image amplitude. Using an aberration free objective lens, for X=0 one sees the object amplitude, for X= π/2 (“Zernike phase contrast”) the object phase. For a real objective lens, however, the wave aberration is given by X(R) = 2π (.25 Csλ3R4 + 0.5ΔzλR2), Cs meaning the coefficient of spherical aberration and Δz defocusing. Consequently, the transfer functions sin X(R) and cos(X(R)) strongly depend on R such that amplitude and phase of the image wave represent only fragments of the object which, fortunately, supplement each other. However, recording only the amplitude gives rise to the fundamental problems, restricting resolution and interpretability of ordinary electron images:

Perancangan Sistem Kontrol Lampu Lalulintas Cerdas Dengan Menggunakan Mikrokontroler dan Kamera

Jurnal MIPA ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 200
Author(s):  
Tjerie Pangemanan ◽  
Arnold Rondonuwu
Keyword(s):  
Real Time ◽  
Digital Image ◽  
Red Light ◽  
Green Light ◽  
Processing Method ◽  
Traffic Lights ◽  
Traffic System ◽  
Road Users ◽  
Adjustment System ◽  
System Time

Masalah lalu lintas  merupakan salah satu  masalah yang sangat sulit diatasi dengan hanya menggunakan system waktu (timer). Oleh sebab itu diperlukan suatu system pengaturan otomatis yang bersifat real-time sehingga waktu pengaturan lampu lalu lintas dapat disesuaikan dnegan keadaan di lapangan. Penelitian ini bertujuan mengembangkan suatu simulasi sistem yang mampu mengestimasi panjang antrian kendaraan menggunakan metoda pengolahan citra digital hanya dengan menggunakan satu kamera untuk dijadikan parameter masukan  dalam menghitung lama waktu nyala lampu merah dan lampu hijau. Oleh karena itu, sistem lalulintas sangatlah diperlukan, sebagai sarana dan prasarana untuk menjadikan lalulintas lancar, aman, bahkan sebagai media pembelajaran disiplin bagi masyarakat pengguna jalan raya. Penelitian ini penulis menggunakan sistem pengontrolan berbasis citra digital dimana camera sebagai sensor. Untuk aplikasi dari  semua metode dalam penelitian ini digunakan Microcontroller AurdinoTraffic problems is one of the problems that is very difficult to overcome by only using the system time (timer). Therefore we need an automatic real-time adjustment system so that the time settings for traffic lights can be adjusted according to the conditions on the ground. This study aims to develop a system simulation that is able to estimate the length of the vehicle queue using a digital image processing method using only one camera to be used as input parameters in calculating the length of time the red light and green light. Therefore, the traffic system is very necessary, as a means and infrastructure to make traffic smooth, safe, even as a medium for disciplined learning for road users. In this study the authors used a digital image-based control system where the camera as a sensor. For the application of all methods in this study, Aurdino Microcontroller is used

scholarly journals Modeling Energy LED Light Consumption Based on an Artificial Intelligent Method Applied to Closed Plant Production System

2021 ◽  
Vol 11 (6) ◽  
pp. 2735
Author(s):  
Ernesto Olvera-Gonzalez ◽  
Martín Montes Rivera ◽  
Nivia Escalante-Garcia ◽  
Eduardo Flores-Gallegos
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Nonlinear Models ◽  
Light Emitting Diode ◽  
Red Light ◽  
Green Light ◽  
Plant Production ◽  
Production Plant ◽  
Light Component ◽  
Gp Model

Artificial lighting is a key factor in Closed Production Plant Systems (CPPS). A significant light-emitting diode (LED) technology attribute is the emission of different wavelengths, called light recipes. Light recipes are typically configured in continuous mode, but can also be configured in pulsed mode to save energy. We propose two nonlinear models, i.e., genetic programing (GP) and feedforward artificial neural networks (FNNs) to predict energy consumption in CPPS. The generated models use the following input variables: intensity, red light component, blue light component, green light component, and white light component; and the following operation modes: continuous and pulsed light including pulsed frequency, and duty cycle as well energy consumption as output. A Spearman's correlation was applied to generate a model with only representative inputs. Two datasets were applied. The first (Test 1), with 5700 samples with similar input ranges, was used to train and evaluate, while the second (Test 2), included 160 total datapoints in different input ranges. The metrics that allowed a quantitative evaluation of the model's performance were MAPE, MSE, MAE, and SEE. Our implemented models achieved an accuracy of 96.1% for the GP model and 98.99% for the FNNs model. The models used in this proposal can be applied or programmed as part of the monitoring system for CPPS which prioritize energy efficiency. The nonlinear models provide a further analysis for energy savings due to the light recipe and operation light mode, i.e., pulsed and continuous on artificial LED lighting systems.

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