query: where are most of the cones located in the eye

pos: Cone cell Cone cell Cone cells, or cones, are one of 3 types of photoreceptor cells in the retina of mammalian eyes (e.g. the human eye). They are responsible for color vision and function best in relatively bright light, as opposed to rod cells, which work better in dim light. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. There are about six to seven million cones in a human eye and are most concentrated towards the macula. The

pos: Cone cell Cone cell Cone cells, or cones, are one of 3 types of photoreceptor cells in the retina of mammalian eyes (e.g. the human eye). They are responsible for color vision and function best in relatively bright light, as opposed to rod cells, which work better in dim light. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. There are about six to seven million cones in a human eye and are most concentrated towards the macula. The

pos: Fovea centralis Fovea centralis The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the macula lutea of the retina. The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities where visual detail is of primary importance, such as reading and driving. The fovea is surrounded by the "parafovea" belt, and the "perifovea" outer region. The parafovea is the intermediate belt, where the ganglion cell layer is composed of more than five rows of cells, as well as the highest

neg: Cone cell L cones are stimulated slightly more than the M cones, and the color red is perceived when the L cones are stimulated significantly more than the M cones. Similarly, blue and violet hues are perceived when the S receptor is stimulated more. Cones are most sensitive to light at wavelengths around 420 nm. However, the lens and cornea of the human eye are increasingly absorptive to shorter wavelengths, and this sets the short wavelength limit of human-visible light to approximately 380 nm, which is therefore called 'ultraviolet' light. People with aphakia, a condition where the eye lacks a lens, sometimes

neg: Visual processing The retina is where a group of light-sensing cells, called photoreceptors are located. There are two types of photoreceptors: rods and cones. Rods are sensitive to dim light and cones are better able to transduce bright light. Photoreceptors connect to bipolar cells, which induce action potentials in retinal ganglion cells. These retinal ganglion cells form a bundle at the optic disc, which is a part of the optic nerve. The two optic nerves from each eye meet at the optic chiasm, where nerve fibers from each nasal retina cross which results in the right half of each eye's visual field

neg: Cone cell report the ability to see into the ultraviolet range. At moderate to bright light levels where the cones function, the eye is more sensitive to yellowish-green light than other colors because this stimulates the two most common (M and L) of the three kinds of cones almost equally. At lower light levels, where only the rod cells function, the sensitivity is greatest at a blueish-green wavelength. Cones also tend to possess a significantly elevated visual acuity because each cone cell has a lone connection to the optic nerve, therefore, the cones have an easier time telling that two stimuli are

neg: Monochromacy a different range of wavelengths. Rods outnumber cones by about 20 to 1 in the human retina, but cones provide about 90% of the brain's input. Cones respond faster than rods and have three types of pigments with different color sensitivities, where rods only have one and so are achromatic (colorless). Because of the distribution of rods and cones in the human eye, people have good color vision near the fovea (where cones are) but not in the periphery (where the rods are). These types of color blindness can be inherited, resulting from alterations in cone pigments or in other

neg: Disc shedding Disc shedding Disc shedding is the process by which photoreceptors in the eye are renewed. The retina contains two types of photoreceptor – rod cells and cone cells. There are about 6-7 million cones that provide color vision to the eye, and they are very concentrated in a central spot in the retina, called the macula. However, the rods are much more numerous – about 120 million – and are also more sensitive than the cones. These rods are responsible for scotopic (night) vision, our most sensitive motion detection, and our peripheral vision. Vertebrate photoreceptors are composed of a photosensitive

neg: Color the "long-wavelength cones", "L cones", or "red cones", are most sensitive to light is perceived as greenish yellow, with wavelengths around 570 nm. Light, no matter how complex its composition of wavelengths, is reduced to three color components by the eye. Each cone type adheres to the principle of univariance, which is that each cone's output is determined by the amount of light that falls on it over all wavelengths. For each location in the visual field, the three types of cones yield three signals based on the extent to which each is stimulated. These amounts of stimulation are sometimes

neg: Macula of retina shown to prevent the disease. After death or enucleation (removal of the eye) the macula appears yellow, a color that is not visible in the living eye except when viewed with light from which red has been filtered. Structures in the macula are specialized for high-acuity vision. Within the macula are the fovea and foveola that both contain a high density of cones, which are nerve cells that are photoreceptors with high acuity. In details, the normal human eye contains three different types of cones, with different ranges of spectral sensitivity. The brain combines the signals from neighboring cones to

neg: Photoreceptor cell rods and cones are intermingled. No photoreceptors are found at the blind spot, the area where ganglion cell fibers are collected into the optic nerve and leave the eye. The photoreceptor proteins in the three types of cones differ in their sensitivity to photons of different wavelengths (see graph). Since cones respond to both the wavelength and intensity of light, the cone's sensitivity to wavelength is measured in terms of its relative rate of response if the intensity of a stimulus is held fixed, while the wavelength is varied. From this, in turn, is inferred the absorbance. The graph normalizes

neg: Dark adaptation threshold Dark adaptation threshold Dark Adaptation Threshold (DAT) is a vision test that measures the adjustment of the eye occurring under low levels of illumination. When light enters the eye, it ultimately reaches the rods and cones, which are two types of cells in the retina. Rods handle vision in low light conditions and cones handle color vision and detail. The rods and cones each react differently during the DAT test, and are measured on a graph. The test determines the threshold, or minimum light intensity required to produce a visual sensation in the child's eye. In order to perform this

neg: Visual system the ultraviolet, while pit vipers can accurately target prey with their pit organs, which are sensitive to infrared radiation. The mantis shrimp possesses arguably the most complex visual system in any species. The eye of the mantis shrimp holds 16 color receptive cones, whereas humans only have three. The variety of cones enables them to perceive an enhanced array of colors as a mechanism for mate selection, avoidance of predators, and detection of prey. Swordfish also possess an impressive visual system. The eye of a swordfish can generate heat to better cope with detecting their prey at depths of 2000

neg: Mormyridae The retina of their eyes is called a "grouped retina", a type of eye structure seen in mormyrids and a few other fish. Instead of being smooth, their retina is composed of tiny cups, acting like parabolic mirrors. Because of the murky waters, the cones in their eyes have adapted to see only red light. The cups are made of four layers of light reflecting proteins, funneling red light to areas of cones, intensifying its brightness 10-fold, while the rods are hit by light from other wavelengths. Only a single gonad is present, located on the left side of their

neg: Platynereis dumerilii four weeks, when six segments have formed, the head is formed. "Platynereis dumerilii" larvae possess two kinds of photoreceptor cells: Rhabdomeric and ciliary photoreceptor cells. The ciliary photoreceptor cells are located in the deep brain of the larva. They are not shaded by pigment and thus perceive non-directional light. The ciliary photoreceptor cells resemble molecularly and morphologically the rods and cones of the human eye. Additional, they express an ciliary opsin that is more similar to the visual ciliary opsins of vertebrate rods and cones than to the visual rhabdomeric opsins of invertebrates. Therefore, it is thought that the urbilaterian,

neg: Four Craters Lava Field Four Craters Lava Field Four Craters Lava Field is a basaltic volcanic field located south east of Newberry Caldera in the U.S. state of Oregon. The volcanic field covers about 30 square kilometers. Four Pleistocene cinder cones are the source of the flows in the field and are aligned along a fissure trending N 30° W. The cones rise 75 to 120 meters above the flows and the distance between the northern most and southern most cones is about 3.5 kilometers. Closely related to the Four Craters lava field is Crack-in-the-Ground located at the southwest corner of the field. The

neg: Eye three types of cones, maximally sensitive to long-wavelength, medium-wavelength, and short-wavelength light (often referred to as red, green, and blue, respectively, though the sensitivity peaks are not actually at these colours). The colour seen is the combined effect of stimuli to, and responses from, these three types of cone cells. Cones are mostly concentrated in and near the fovea. Only a few are present at the sides of the retina. Objects are seen most sharply in focus when their images fall on the fovea, as when one looks at an object directly. Cone cells and rods are connected through intermediate

neg: Cinder cone of a surrounding pad of lava. If the crater is fully breached, the remaining walls form an amphitheatre or horseshoe shape around the vent. Cinder cones are commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. For example, geologists have identified nearly 100 cinder cones on the flanks of Mauna Kea, a shield volcano located on the island of Hawaii. These cones are also referred to as 'scoria cones' and 'cinder and spatter cones.' The most famous cinder cone, Paricutin, grew out of a corn field in Mexico in 1943 from a new vent. Eruptions continued for nine

neg: Hemeralopia light), which is typical of inflammations of eye. Nighttime vision largely remains unchanged due to the use of rods as opposed to cones (during the day), which are affected by hemeralopia and in turn degrade the daytime optical response. Hence, many patients feel they see better at dusk than in daytime. Hemeralopia is known to occur in several ocular conditions. Cone dystrophy and achromatopsia, affecting the cones in the retina, and the anti-epileptic drug trimethadione are typical causes. Adie's pupil, which fails to constrict in response to light; aniridia, which is absence of the iris; and albinism, where the iris

neg: Fovea centralis of the cone mosaic, and the fovea is the area of the eye with the highest sensitivity to fine details. Cones in the central fovea express pigments that are sensitive to green and red light. These cones are the 'midget' pathways that also underpin high acuity functions of the fovea. The fovea is employed for accurate vision in the direction where it is pointed. It comprises less than 1% of retinal size but takes up over 50% of the visual cortex in the brain. The fovea sees only the central two degrees of the visual field, (approximately twice the width

neg: Dark adaptor goggles Trendelenburg in 1916. The concept is based on the work by Antoine Béclère on dark adaptation of the eye, where it is noted that fluoroscopy relies on the use of the retinal rods of the eye. Since retinal rods are insensitive to long wavelengths of light, such as red light, while retinal cones are not, the goggles enabled the physicians to adapt their eyes in preparation for the fluoroscopic procedure while still being able to perform other work. Prior to the invention of these goggles, physicians were required to sit in the darkened room where the procedure would be performed

neg: Ulysses Colles of Ulysses Colles are spread over an area of about 50 to 80 km and their spatial distribution seem to be controlled by N- to NNW-trending normal faults. The distribution is not random, more cones are located in the southern part, where are forming clusters of overlapping cones. Also, the southern cones seem to be more preserved than northern cones. Ulysses Colles Ulysses Colles is an official name for conical edifices associated with flows in Ulysses Fossae in the Tharsis quadrangle of Mars. These conical edifices form small volcanic field which were interpreted as result of explosive eruptions on Mars

neg: Spontaneous parametric down-conversion resultant correlated photon pairs have trajectories that are constrained to be within two cones, whose axes are symmetrically arranged relative to the pump beam. Also, due to the conservation of momentum, the two photons are always symmetrically located within the cones, relative to the pump beam. Importantly, the trajectories of the photon pairs may exist simultaneously in the two lines where the cones intersect. This results in entanglement of the photon pairs whose polarization are perpendicular. Another crystal is KDP (Potassium Dihydrogen Phosphate) which is mostly used in Type I down conversion, where both photons have the same polarization. SPDC

neg: Mammalian eye synapse. Differences between the rhodopsin and the iodopsins is the reason why cones and rods enable organisms to see in dark and light conditions — each of the photoreceptor proteins requires a different light intensity to break down into the constituent products. Further, synaptic convergence means that several rod cells are connected to a single bipolar cell, which then connects to a single ganglion cell by which information is relayed to the visual cortex. This convergence is in direct contrast to the situation with cones, where each cone cell is connected to a single bipolar cell. This divergence results in

neg: Optic disc Optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form the optic nerve after they leave the eye. The optic disc represents the beginning of the optic nerve and is the point where the axons of retinal ganglion cells come together. The optic disc is also the entry point for the major blood vessels that supply the retina. The optic disc in a

neg: Optic disc patients without glaucoma. Optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form the optic nerve after they leave the eye. The optic disc represents the beginning of the optic nerve and is the point where the axons of retinal ganglion cells come together. The optic disc is also the entry point for the major blood vessels that supply the retina. The optic

neg: Optic disc drusen retinal ganglion cell axons. The optic nerve head, or optic disc is the anterior end of the nerve that is in the eye and hence is visible with an ophthalmoscope. It is located nasally and slightly inferior to the macula of the eye. There is a blind spot at the optic disc because there are no rods or cones beneath it to detect light. The central retinal artery and vein can be seen in the middle of the disc as it exits the scleral canal with the optic nerve to supply the retina. The vessels send branches out in all

neg: Retinal haemorrhage and flaxseed oil. Retinal haemorrhage Retinal haemorrhage is a disorder of the eye in which bleeding occurs in the retina, the light sensitive tissue, located on the back wall of the eye. There are photoreceptor cells in the retina called rods and cones, which transduce light energy into nerve signals that can be processed by the brain to form visual images. Retinal hemorrhage can affect adults, and newborn babies and infants may also suffer from this disorder. A retinal hemorrhage can be caused by several medical conditions such as hypertension, retinal vein occlusion (a blockage of a retinal vein), anemia,

neg: Retinal haemorrhage Retinal haemorrhage Retinal haemorrhage is a disorder of the eye in which bleeding occurs in the retina, the light sensitive tissue, located on the back wall of the eye. There are photoreceptor cells in the retina called rods and cones, which transduce light energy into nerve signals that can be processed by the brain to form visual images. Retinal hemorrhage can affect adults, and newborn babies and infants may also suffer from this disorder. A retinal hemorrhage can be caused by several medical conditions such as hypertension, retinal vein occlusion (a blockage of a retinal vein), anemia, leukemia or diabetes

neg: Uruk period attention is a succession of monuments which are definitely for cultic purposes. The 'Eye Temple' (as its final stage is known) has walls decorated with terracotta cones which form a mosaic and with inlays of coloured stones and a platform which might have been an altar and is decorated with gold leaf, lapis lazuli, silver nails, and white marble in a central T-shaped room. The most remarkable find are over two hundred "eye figurines" which give the building its name. These figurines have enormous eyes and are definitely votive deposits. Tell Brak has also produced evidence of writing: a numeric

neg: Green the dark-adapted human eye is greatest at about 507nm, a blue-green color, while the light-adapted eye is most sensitive about 555nm, a yellow-green; these are the peak locations of the rod and cone (scotopic and photopic, respectively) luminosity functions. The perception of greenness (in opposition to redness forming one of the opponent mechanisms in human color vision) is evoked by light which triggers the medium-wavelength "M" cone cells in the eye more than the long-wavelength "L" cones. Light which triggers this greenness response more than the yellowness or blueness of the other color opponent mechanism is called green. A green

neg: Color blindness sets of color sensing cones in the eye. Males are more likely to be color blind than females, as the genes responsible for the most common forms of color blindness are on the X chromosome. As females have two X chromosomes, a defect in one is typically compensated for by the other, while males only have one X chromosome. Color blindness can also result from physical or chemical damage to the eye, optic nerve or parts of the brain. Diagnosis is typically with the Ishihara color test; however, a number of other testing methods also exist. There is no cure

neg: Mesopic vision for formula_5 are shown in the table below. Mesopic vision Mesopic vision is a combination of photopic vision and scotopic vision in low but not quite dark lighting situations. Mesopic light levels range from luminances of approximately 0.001 to 3 cd m. Most night-time outdoor and traffic lighting scenarios are in the mesopic range. Humans see differently at different light levels. This is because under high light levels typical during the day (photopic vision), the eye uses cones to process light. Under very low light levels, corresponding to moonless nights without electric lighting (scotopic vision), the eye uses rods to

neg: Toussidé vertical. Inside of Trou au Natron are several recent basaltic volcanic cones, the most remarkable of which is the high Moussosomi, which has erupted a lava flow. Three of these cones are deeply eroded. Cones are also located outside of the Trou au Natron, and their eruption products have in part flowed into the crater. Like Toussidé, the position of Trou au Natron appears to be controlled by the ring fault of the "pre-Toussidé" caldera. A salty swamp lies within Trou au Natron, whose floor is in part covered by evaporites, mainly sodium sulfate. Another wide and deep crater, Doon

neg: Simcoe Mountains Simcoe Mountains The Simcoe Mountains Volcanic Field is a group of lava flows and extinct cinder cones located in the United States in south-central Washington state, east of Mount Adams. The Northern and central sections of the Simcoe Mountains are located in Yakama Indian Reservation. Although the volcanic field is located near the Cascade Arc of volcanoes, it is a much older intraplate volcanic field, and not a part of the Cascade Arc. Most of the volcanic cones are 75 m to 250 m taller than the surrounding land, except for Signal Peak Shield, which is 500 m taller than

neg: Larix laricina more years old. Cones usually are produced on young growth of vigorous trees. On open-grown trees, cones are borne on all parts of the crown. Mature seed cones are brown, oblong-ovoid, and long. The wood is tough and durable, but also flexible in thin strips, and was used by the Algonquian people for making snowshoes and other products where toughness was required. The natural crooks located in the stumps and roots are also preferred for creating knees in wooden boats. Currently, the wood is used principally for pulpwood, but also for posts, poles, rough lumber, and fuelwood; it is not

neg: Cone cell and outer segments are connected by a cilium. The inner segment contains organelles and the cell's nucleus, while the outer segment, which is pointed toward the back of the eye, contains the light-absorbing materials. Unlike rods, the outer segments of cones have invaginations of their cell membranes that create stacks of membranous disks. Photopigments exist as transmembrane proteins within these disks, which provide more surface area for light to affect the pigments. In cones, these disks are attached to the outer membrane, whereas they are pinched off and exist separately in rods. Neither rods nor cones divide, but their membranous

neg: Opponent process at odds, it later came to be understood that the mechanisms responsible for the opponent process receive signals from the three types of cones and process them at a more complex level. Besides the cones, which detect light entering the eye, the biological basis of the opponent theory involves two other types of cells: bipolar cells, and ganglion cells. Information from the cones is passed to the bipolar cells in the retina, which may be the cells in the opponent process that transform the information from cones. The information is then passed to ganglion cells, of which there are two

neg: Adaptation (eye) cones in the eye are the major contributors to dark adaptation. Above a certain luminance level (about 0.03 cd/m), the cone mechanism is involved in mediating vision; photopic vision. Below this level, the rod mechanism comes into play providing scotopic (night) vision. The range where two mechanisms are working together is called the mesopic range, as there is not an abrupt transition between the two mechanism. This adaptation forms the basis of the Duplicity Theory. Many animals such as cats possess high-resolution night vision, allowing them to discriminate objects with high frequencies in low illumination settings. The "tapetum lucidum" is

neg: Andagua volcanic field Gloriahuasi, more akin to a small stratovolcano. They are comparable to many other Central Andean scoria cones. Many of them predate the last glaciation, given the degree of weathering and aeolian burying. The youngest of these are located in the Andagua valley. Jenchaña () has the longest lava flow of the field, reaching down almost to the Colca canyon. These cones have heights of and diameters of . Most centres are located on the valley floors but a few formed in their shoulders; these frequently contain xenoliths. Lava flows have volumes of around and lengths between four and eight kilometres.

neg: Eccentricity effect when objects projected directly onto the fovea are the sharpest, while those further out in the periphery of the retina become steadily less focused. This is due to the distribution of cones and rods throughout the retina. When we view an image, light passes through the cornea, and through the pupil, which is controlled by the iris. It then passes through the lens and is projected onto the retina at the back of the eye. In the middle of the retina is the fovea, which contains a high concentration of cones. Cones are responsible for colour vision and have high

neg: Gene therapy for color blindness of 2018 there is no medical entity offering this treatment, and no clinical trials available for volunteers. The retina of the human eye contains photoreceptive cells called cones that allow color vision. A normal trichromat individual possesses three different types of cones to distinguish different colors within the visible spectrum from 380 nm to 740 nm. The three types of cones are designated L, M, and S cones, and each type is sensitive to a certain range of wavelength of light depending on what photopigment it contains. More specifically, the L cone absorbs around 560 nm, the M cone absorbs

neg: Kwik cricket leg side and off side fielders). Equipment: In Australia and New Zealand the game is more formal than in the UK, where the rules include a one-handed catch resulting in the dismissal of the entire team, and rather than plastic cones a nearby landmark is used as a theoretical boundary. Cones are placed next to the batsman's left and right leg (about one metre away), Tennis balls are placed on these cones. In most cases in Australia, if the bowler bowls a no-ball, wide, dead ball, etc., the person batting would hit either of the cones for a "free shot".

neg: Color is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. Humans are trichromatic—the retina contains three types of color receptor cells, or cones. One type, relatively distinct from the other two, is most responsive to light that is perceived as blue or blue-violet, with wavelengths around 450 nm; cones of this type are sometimes called "short-wavelength cones", "S cones", or "blue cones". The other two types are closely related genetically and chemically: "middle-wavelength cones", "M cones", or "green cones" are most sensitive to light perceived as green, with wavelengths around 540 nm, while

neg: Optics first through the cornea, which provides much of the eye's optical power. The light then continues through the fluid just behind the cornea—the anterior chamber, then passes through the pupil. The light then passes through the lens, which focuses the light further and allows adjustment of focus. The light then passes through the main body of fluid in the eye—the vitreous humour, and reaches the retina. The cells in the retina line the back of the eye, except for where the optic nerve exits; this results in a blind spot. There are two types of photoreceptor cells, rods and cones,

neg: Baleen whale at the retina, enhancing eyesight in dark areas. However, light is bent more near the surface of the eye when in air as opposed to water; consequently, they can see much better in the air than in the water. The eyeballs are protected by a thick outer layer to prevent abrasions, and an oily fluid (instead of tears) on the surface of the eye. Baleen whales appear to have limited color vision, as they lack S-cones. The mysticete ear is adapted for hearing underwater, where it can hear sound frequencies as low as 7 Hz and as high as 22

neg: Rod cell at all at night. Rods are a little longer and leaner than cones but have the same basic structure. Opsin-containing disks lie at the end of the cell adjacent to the retinal pigment epithelium, which in turn is attached to the inside of the eye ball. The stacked-disc structure of the detector portion of the cell allows for very high efficiency. Rods are much more common than cones, with about 100 million rod cells compared to 7 million cone cells. Like cones, rod cells have a synaptic terminal, an inner segment, and an outer segment. The synaptic terminal forms a

neg: Retina entire retina contains about 7 million cones and 75 to 150 million rods. The optic disc, a part of the retina sometimes called "the blind spot" because it lacks photoreceptors, is located at the optic papilla, where the optic-nerve fibres leave the eye. It appears as an oval white area of 3 mm². Temporal (in the direction of the temples) to this disc is the macula, at whose centre is the fovea, a pit that is responsible for our sharp central vision but is actually less sensitive to light because of its lack of rods. Human and non-human primates possess

neg: Receptive field binocular neurons in the visual cortex, receptive fields do not extend to optical infinity. Instead, they are restricted to a certain interval of distance from the animal, or from where the eyes are fixating (see Panum's area). The receptive field is often identified as the region of the retina where the action of light alters the firing of the neuron. In retinal ganglion cells (see below), this area of the retina would encompass all the photoreceptors, all the rods and cones from one eye that are connected to this particular ganglion cell via bipolar cells, horizontal cells, and amacrine cells.

neg: Mesopic vision Mesopic vision Mesopic vision is a combination of photopic vision and scotopic vision in low but not quite dark lighting situations. Mesopic light levels range from luminances of approximately 0.001 to 3 cd m. Most night-time outdoor and traffic lighting scenarios are in the mesopic range. Humans see differently at different light levels. This is because under high light levels typical during the day (photopic vision), the eye uses cones to process light. Under very low light levels, corresponding to moonless nights without electric lighting (scotopic vision), the eye uses rods to process light. At many night-time levels, a combination

neg: Mammalian eye cannot see dim stars, or other celestial objects, using central vision because the light from these is not enough to stimulate cone cells. Because cone cells are all that exist directly in the fovea, astronomers have to look at stars through the "corner of their eyes" (averted vision) where rods also exist, and where the light "is" sufficient to stimulate cells, allowing an individual to observe faint objects. Rods and cones are both photosensitive, but respond in different ways to different frequencies of light. They contain different pigmented photoreceptor proteins. Rod cells contain the protein rhodopsin and cone cells contain

neg: Light of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it. Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones located in the retina of the human eye cannot detect the very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses (such as insects

neg: Role of cell adhesions in neural development to direction cue, thereby directing neuronal axons. Growth cones are known to respond to various mechanical cues, which may be vital in proper nervous system development as growth cones experience a wide variety of mechanical environments as they navigate the extracellular space. Research suggests that growth cones from different regions of the brain may respond to mechanical cues differently. It has been demonstrated that neural cells located in the hippocampus aren't sensitive to varying mechanical stiffness as it related to outgrowth, where cells originating from the dorsal root ganglion show maximal outgrowth on surfaces of approximately 1 kPa. Both hippocampal

neg: Mammalian eye In the human eye, light enters the pupil and is focused on the retina by the lens. Light-sensitive nerve cells called rods (for brightness), cones (for color) and non-imaging ipRGC (intrinsincally photosensitive retinal ganglion cells) react to the light. They interact with each other and send messages to the brain. The rods and cones enable vision. The ipRGCs enable entrainment to the Earth's 24-hour cycle, resizing of the pupil and acute suppression of the pineal hormone melatonin. The retina contains three forms of photosensitive cells, two of them important to vision, rods and cones, in addition to the subset of

neg: Monochromacy continuous band of frequencies, retinal ganglion cells and the visual cortex. Rods, which are extremely abundant (about 120 million), are in the periphery of the human retina. Rods respond only to faint levels of light and are very light sensitive, therefore, completely useless in daylight because bright light bleaches them. Cones, which are mostly near the fovea in the eye and are less active in dim light, more useful in bright light, are essential for color vision. There are three types of cones in normal human eyes (short, medium and long wavelength, sometimes called blue, green and red); each detects

neg: Melanopsin eyes play a critical role in the photoentrainment of the circadian pacemaker. In mutant breeds of mice that lacked only rods, only cones, or both rods and cones, all breeds of mice still entrained to changing light stimuli in the environment, but with a limited response, suggesting that rods and cones are not necessary for circadian photoentrainment and that the mammalian eye must have another photopigment required for the regulation of the circadian clock. Melanopsin-knockout mice display reduced photoentrainment. In comparison to wild-type mice that expressed melanopsin normally, deficits in light-induced phase shifts in locomotion activity were noted in melanopsin-null

neg: Color vision differential output of these cells in the retina and it will be finalized in the visual cortex and associative areas of the brain. For example, while the L cones have been referred to simply as red receptors, microspectrophotometry has shown that their peak sensitivity is in the greenish-yellow region of the spectrum. Similarly, the S- and M-cones do not directly correspond to blue and green, although they are often described as such. The RGB color model, therefore, is a convenient means for representing color, but is not directly based on the types of cones in the human eye. The peak

neg: Guild Wars: Eye of the North North", with a few gameplay alterations being made to accommodate dungeon exploration. Most "Eye of the North" dungeon levels have an area map located somewhere near the entrance. This map does not expose the layout of the level, but does place indicators on the mission map where key items (keys, bosses, collectors, etc.) are located. In addition, reaching certain areas of the dungeon, particularly the final boss, will place a marker on the overhead map, indicating where that location is. Dungeon levels also frequently include locked doors which require a specific key to unlock. Unlike most key-like items in earlier

neg: Impossible color eye in normal circumstances seeing any possible light spectrum. Thus, no object can have an imaginary color. But such imaginary colors are useful as mathematical abstractions for defining color spaces. The spectral sensitivity curve of medium-wavelength ("M") cone cells overlaps those of short-wavelength ("S") and long-wavelength ("L") cone cells. Light of any wavelength that interacts with M cones also interacts with S or L cones, or both, to some extent. Therefore, no wavelength (except perhaps a bit of the far red), and no non-negative spectral power distribution, excites only one sort of cone. If, for example, M cones could be

neg: Boring Lava Field the eastern part of the Boring cluster, volcanic vents have average diameters less than , with average heights less than from base to summit. The lava flows from Highland Butte and Larch Mountain, both shield volcanoes, encompass a wide area, with Boring Lava deposits averaging thicknesses of not considering areas next to volcanic cones in the field. Most of the summit craters have been destroyed, though there are partial craters at Bobs Hill (located northeast of Portland) and Battleground Lake (located north of Portland); Mount Scott also has an intact summit crater. However, many of the Boring cones retain the

neg: Eccentricity effect spatial acuity, whereas rods are not. Rods are instead responsible for vision at lower light. Cones are much more sparsely located in the periphery of the retina, where there is instead a greater concentration of rods. When a central image is projected directly onto the fovea it is sharper and processed with greater speed and accuracy due to these cones, whereas images further in the periphery (greater eccentricity) are processed more slowly and less accurately. Cortical magnification is one such visual explanation and is referring to the variance of the number of neurons that exist in the visual cortex, which

neg: Double cone (biology) the double cones. Double cone (biology) Double cones (DCs), known as twin cones when the two members are the same, are two cone cells (colour detecting photoreceptors) joined together that may also be coupled optically/electrically. They are the most common type of cone cells in fish, reptiles and birds, and are present in most vertebrates, though they have been noted as absent in placental mammals (including humans), elasmobranches and catfish. There are many gap junctions between the cells of fish double cones. Their function, if they have any unique function compared to single cones, is largely unknown; proposed uses include

neg: Uruk period sites have been excavated in the region of Samsat (also in the Euphrates valley). An Urukian site was revealed at Samsat during a hasty rescue excavation before the area was flooded as a result of the construction of a hydroelectric dam. Fragments of clay cones from a wall mosaic were found. A little to the south is Kurban Höyük, where clay cones and pottery characteristic of Uruk have also been found in tripartite buildings. Further to the north, the site of Arslantepe, located in the suburbs of Malatya, is the most remarkable site of the period in eastern Anatolia. It

neg: Cone cell commonly cited figure of six million cone cells in the human eye was found by Osterberg in 1935. Oyster's textbook (1999) cites work by Curcio et al. (1990) indicating an average close to 4.5 million cone cells and 90 million rod cells in the human retina. Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. Cones are

neg: Pteropus vision. Like most mammals, though not primates, they are dichromatic. They have both rods and cones; they have "blue" cones that detect short-wavelength light and "green" cones that detect medium-to-long-wavelengths. The rods greatly outnumber the cones, however, as cones comprise only 0.5% of photoreceptors. Flying foxes are adapted to seeing in low-light conditions. Flying foxes are poorly represented in the fossil record. Relative to the current number of extant species, Pteropodidae has one of the most incomplete fossil records of any bat group. As of 2014, there are no flying fox fossils from before the Holocene. Many flying foxes live

neg: Actinostrobus acuminatus evergreen and mixed scale-like and needle-like, except on young seedlings, where they are all needle-like. The leaves are arranged in six rows along the twigs, in alternating whorls of three; the scale leaves are 2–4 mm long, the needle leaves 10–20 mm long. The male cones are small, 3–6 mm long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, but mature in 18–20 months to 15–20 mm long, with a pointed apex. Actinostrobus acuminatus Actinostrobus acuminatus, commonly known as dwarf cypress, creeping pine or Moore cypress pine, is a species of coniferous

neg: Adaptation (eye) light adaptation can be measured clinically. In an increment threshold experiment, a test stimulus is presented on a background of a certain luminance, the stimulus is increased until the detection threshold is reached against the background. A monophasic or biphasic threshold versus intensity TVI curve is obtained through this method for both cones and rods. When the threshold curve for a single system (i.e., just cones or just rods) is taken in isolation it can be seen to possesses four sections: Insufficiency of adaptation most commonly presents as insufficient adaptation to dark environment, called night blindness or "nyctalopia". The opposite

neg: Cone cell white or have white spots. A white glow in the eye is often seen in photographs taken with a flash, instead of the typical "red eye" from the flash, and the pupil may appear white or distorted. Other symptoms can include crossed eyes, double vision, eyes that do not align, eye pain and redness, poor vision or differing iris colors in each eye. If the cancer has spread, bone pain and other symptoms may occur. Cone cell Cone cells, or cones, are one of 3 types of photoreceptor cells in the retina of mammalian eyes (e.g. the human eye). They

neg: Optic disc the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The eye is unique because of the transparency of its optical media. Almost all eye structures can be examined with appropriate optical equipment and lenses. Using a modern direct ophthalmoscope gives a view of the optic disc using the principle of reversibility of light. A slit lamp biomicroscopic examination along with an appropriate aspheric focusing lens (+66D, +78D or +90D) is required for a detailed stereoscopic view of the optic disc and structures inside the eye. A

neg: Volcanic cone unconsolidated, cinder cones tend to erode rapidly unless further eruptions occur. Rootless cones, also called pseudocraters, are volcanic cones that are not directly associated with a conduit that brought magma to the surface from a deep-seated magma reservoir. Generally, three types of rootless cones, littoral cones, explosion craters, and hornitos are recognized. Littoral cones and explosion craters are the result of mild explosions that were generated locally by the interaction of either hot lava or pyroclastic flows with water. Littoral cones typically form on the surface of a basaltic lava flow where it has entered into a body of water,

neg: Volcanic cone tuff rings are associated with eruptions within either water saturated sediments and bedrock or permafrost Next to spatter (scoria) cones, tuff cones and their associated tuff rings are among the most common types of volcanoes on Earth. An example of a tuff cone is Diamond Head at Waikīkī in Hawaii. Clusters of pitted cones observed in the Nephentes/Amenthes region of Mars at the southern margin of the ancient Utopia impact basin are currently interpreted as being tuff cones and rings. Cinder cones, also known as scoria cones and less commonly scoria mounds, are small, steep-sided volcanic cones built of loose

neg: Eye cells used for vision: the rods and the cones. Rods cannot distinguish colours, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina. Cones are responsible for colour vision. They require brighter light to function than rods require. In humans, there are

neg: Diselma is "Phaerosphaera hookeriana" (previously known as "Microstrobos niphophilus" ) which is also part of the family Podocarpaceae. Both these species have a similar growth habit and distribution, however, the opposite pairs of leaves on "D. archeri" again make it distinguishable from the other species. Bark is rough and scaly and often weathered revealing a reddish-brown inner bark. Being a gymnosperm no flowers are produced, instead seed development occurs on the surface of the scale-like leaves which are modified to form cones (see image). "Diselma archeri" is a dioecious shrub, where male and female cones are located on separate individuals. Both

neg: Visual perception e.g. For a more detailed discussion, see Pizlo (2008). Transduction is the process through which energy from environmental stimuli is converted to neural activity for the brain to understand and process. The back of the eye contains three different cell layers: photoreceptor layer, bipolar cell layer and ganglion cell layer. The photoreceptor layer is at the very back and contains rod photoreceptors and cone photoreceptors. Cones are responsible for color perception. There are three different cones: red, green and blue. Rods, are responsible for the perception of objects in low light. Photoreceptors contain within them a special chemical called a

neg: Traffic cone countries such as Australia or American states such as California, traffic barrels are rarely seen. Devices called bollards are used instead of cones where larger and sturdier warning or delineation devices are needed. Typically, bollards are high fluorescent orange posts with reflective sleeve and heavyweight rubber bases. Larger devices such as barrier boards may be used instead of cones where larger areas need to be excluded or for longer periods. In Canada they are often referred to as pylons. Cones are used to lay out courses for autocross competitions. Cones are also frequently used in indoor public spaces to mark

neg: Volcanic cone on February 20, 1943, and Sunset Crater in Northern Arizona in the US Southwest are classic examples of cinder cones, as are ancient volcanic cones found in New Mexico's Petroglyph National Monument. Cone-shaped hills observed in satellite imagery of the calderas and volcanic cones of Ulysses Patera, Ulysses Colles and Hydraotes Chaos are argued to be cinder cones. Cinder cones typically only erupt once like Paricutin. As a result, they are considered to be monogenetic volcanoes and most of them form monogenetic volcanic fields. Cinder cones are typically active for very brief periods of time before becoming inactive. Their eruptions

neg: Circadian rhythm Destruction of the SCN results in the complete absence of a regular sleep–wake rhythm. The SCN receives information about illumination through the eyes. The retina of the eye contains "classical" photoreceptors ("rods" and "cones"), which are used for conventional vision. But the retina also contains specialized ganglion cells that are directly photosensitive, and project directly to the SCN, where they help in the entrainment (synchronization) of this master circadian clock. These cells contain the photopigment melanopsin and their signals follow a pathway called the retinohypothalamic tract, leading to the SCN. If cells from the SCN are removed and cultured, they

neg: Color Many such sources can still effectively produce a spectral color, as the eye cannot distinguish them from single-wavelength sources. For example, most computer displays reproduce the spectral color orange as a combination of red and green light; it appears orange because the red and green are mixed in the right proportions to allow the eye's cones to respond the way they do to the spectral color orange. A useful concept in understanding the perceived color of a non-monochromatic light source is the dominant wavelength, which identifies the single wavelength of light that produces a sensation most similar to the light

neg: Melanopsin a light-dark cycle. This observation led to the conclusion that neither rods nor cones, located in the outer retina, are necessary for circadian entrainment and that a third class of photoreceptor exists in the mammalian eye. Provencio and colleagues then found in 2000 that melanopsin is also present in mouse retina, specifically in ganglion cells, and that it mediates non-visual photoreceptive tasks. Melanopsin was found to be encoded by Opn4 with orthologs in a variety of organisms. These retinal ganglion cells were found to be innately photosensitive, since they responded to light even while isolated, and were thus named intrinsically

neg: Volcanic cone from . The diameter of their craters ranges between . Cinder cones rarely rise more than or so above their surroundings. Cinder cones most commonly occur as isolated cones in large basaltic volcanic fields. They also occur in nested clusters in association with complex tuff ring and maar complexes. Finally, they are also common as parasitic and monogenetic cones on complex shield and stratovolcanoes. Globally, cinder cones are the most typical volcanic landform found within continental intraplate volcanic fields and also occur in some subduction zone settings as well. Parícutin, the Mexican cinder cone which was born in a cornfield

neg: LRGB see color. The rods in human eyes are sensitive to luminance and spatial data, while the cones are sensitive to color. There are three types of cones: those sensitive to red, those sensitive to green, and those sensitive to blue. Thus, each element of LRGB targets one type of photoreceptor cell in the human eye. LRGB LRGB, short for Luminance, Red, Green and Blue, is a photographic technique used in amateur astronomy for producing good quality color photographs by combining a high-quality black-and-white image with a lower-quality color image. In amateur astronomy, it is easier and cheaper to obtain good

neg: Gecko eye therefore modified its cones that increased in size into different types both single and double. Three different photopigments have been retained and are sensitive to UV, blue, and green. They also use a multifocal optical system that allows them to generate a sharp image for at least two different depths. Most gecko species can lose their tails in defense, a process called autotomy. Many species are well known for their specialised toe pads that enable them to climb smooth and vertical surfaces, and even cross indoor ceilings with ease. Geckos are well known to people who live in warm

neg: Bridge River Cones Bridge River Cones The Bridge River Cones, sometimes referred to as the Lillooet Cones and Salal Creek Cones, is the name given to a volcanic field located on the north flank of the upper Bridge River, about west of the town of Gold Bridge. The cones are in the lee of the Lillooet Icecap and sit astride a group of passes between the Bridge River, which flows W-E to their south, and the Lord River, which flows north to the Taseko Lakes in the Chilcotin District. The Bridge River Cones consist of small trachybasaltic and basaltic eruptive centers. Sham Hill

neg: Albinism are the only known albino mammal to survive successfully in the wild". In all albino mammals studied, the eye color is green, blue or red due to absence of eumelanin in the iris, and the centre of the retina is under-developed with a deficit of rod cells; the central ganglion cell density is approximately 25% below normal. In nearly all mammals, the overwhelming majority of photoreceptors are rods rather than cones. Albinism specifically affects the rod cells, but the number and distribution of the cones is unaffected. The retina of the squirrel ("Sciurus carolinensis") is unusual for mammals as it

neg: Zamia integrifolia "Zamia" species often produce more than one cone close to the tip of the stem or at the terminal of the caudex where it intersects with the aboveground stem. The multiple cones of "Z. floridana" may develop through three methods: sympodium, forking of the bundle system, and adventitious buds. The most common form of development is the rapid formation of cone domes on the plant's sympodium, which is its main axis. More cones are present when there is a "branching" of the bundles to the cones. The forking of the bundle system starts near the base of a terminal cone,

neg: Falso Azufre Falso Azufre Falso Azufre is a complex volcano at the border of Argentina and Chile. Falso Azufre is elongated in east-west direction and contains craters and lava domes; most craters have diameters of with the exception of the main crater, which is wide. The highest summit Cerro Falso Azufre lies at the western end in Chile, which has mostly generated pyroclastic material from craters. The probably youngest segment of the volcano is the eastern section in Argentina, where two lava domes and two cones are located; these form the Dos Conos volcano. Some lava flows linked to Dos Conos are

neg: Cerro Bitiche associated with the Altiplano-Puna volcanic complex. The two major calderas La Pacana and Cerro Guacha are close to Cerro Bitiche, the eastern margin of Guacha's oldest caldera is located just east of Bitiche. Ordovician marine sequences form the tectonic basement of the area, but most of it is covered by ignimbrites and lavas between 8.5-4 million years old. The volcanic field covers a surface area of , including lava flows and scoria cones. The highest scoria cone has a height of . These scoria cones are formed by lapilli and pyroclastics with no welding and also contain lava bombs. They

neg: Double cone (biology) Double cone (biology) Double cones (DCs), known as twin cones when the two members are the same, are two cone cells (colour detecting photoreceptors) joined together that may also be coupled optically/electrically. They are the most common type of cone cells in fish, reptiles and birds, and are present in most vertebrates, though they have been noted as absent in placental mammals (including humans), elasmobranches and catfish. There are many gap junctions between the cells of fish double cones. Their function, if they have any unique function compared to single cones, is largely unknown; proposed uses include achromatic (non-colour vision)

neg: Gene therapy for color blindness color of incoming light. For instance, the color red stimulate L cones more than M cones, whereas the color green stimulates the L and M cones more than the S cones. The colors are perceived in an opponent process, such that red and green are perceived in opposition, as are blue and yellow, black and white. The gene loci coding for the photopigments: M-opsin and L-opsin are located in close proximity within the X chromosome and are highly polymorphic. Among the population, some have a deleted gene for the M photopigment in the X chromosome (such as in deuteranopia), whereas

neg: Alaska plaice Five to seven small boney cones are found on the head on the eyed side. Alaska plaice Alaska plaice ("Pleuronectes quadrituberculatus") is a saltwater fish that live in the North Pacific Ocean. Alaska plaice are right-eye flounders which live on the sandy bottoms of the continental shelf, up to 600 metres deep. Their geographic range is from the Gulf of Alaska in the east, to the Chukchi Sea in the north, to the Sea of Japan in the west. Alaska plaice feed mostly on polychaetes, but also eat amphipods and echiurans. Most commercial fisheries do not target Alaska plaice, and

neg: Retina density of rods converging on single bipolar cells. Since its cones have a much lesser convergence of signals, the fovea allows for the sharpest vision the eye can attain. Though the rod and cones are a mosaic of sorts, transmission from receptors, to bipolars, to ganglion cells is not direct. Since there are about 150 million receptors and only 1 million optic nerve fibres, there must be convergence and thus mixing of signals. Moreover, the horizontal action of the horizontal and amacrine cells can allow one area of the retina to control another (e.g. one stimulus inhibiting another). This inhibition

neg: Opponent process yellow, and black versus white (the last type is achromatic and detects light-dark variation, or luminance). Responses to one color of an opponent channel are antagonistic to those to the other color. That is, opposite opponent colors are never perceived together – there is no "greenish red" or "yellowish blue". While the trichromatic theory defines the way the retina of the eye allows the visual system to detect color with three types of cones, the opponent process theory accounts for mechanisms that receive and process information from cones. Though the trichromatic and opponent processes theories were initially thought to be

neg: Jom-Bolok volcanic field two other flows), Stariy ("old" in Russian, and ), Treshina ("fissure" in Russian) and Troynoy ("triplet" in Russian, three high domes). Most of these cones are located within the Hee-Gol valley rather than the Jom-Bolok valley itself. These cones are constructed on top of three different faults. An alkali basalt lava flow erupted during the Holocene has a volume of and reached a length of along Jom-Bolok river, reaching the Oka river in a large fan and damming it. This volume is comparable to the volume of lavas emitted during the 1973 Tolbachik eruption, albeit smaller than the Eldgja and

neg: Littoral cone lava bench and subsequent steam explosions formed the cones instead. Pyroclastic flows can also form littoral cones, one such cone has been found on Lombok and formed during the 1257 Samalas eruption. Pseudocraters and littoral cones have been found on Iceland, Hawaii, Cerro Azul in the Gálapagos Islands, Deception Island, Antarctica, and Medicine Lake Volcano, California. Sometimes the words "pseudocrater" and "littoral cone" are used as synonyms. Littoral cones are usually quickly removed by sea erosion; thus littoral cones are rare. Prehistorical littoral cones have been found on the coast of Hawaii, where the volcanoes Mauna Loa and Kilauea face

neg: Conifer cone further characteristic arrangement of pines is that the male cones are located at the base of the branch, while the female at the tip (of the same or a different branchlet). However, in larches and cedars, both types of cones are always at the tips of short shoots, while both sexes of fir cones are always from side buds, never terminal. There's also some diversity in bearing in Cupressaceae. Some, "Cupressus" for instance, has little or no differentiation in the positions of male and female cones. Cone crop potential can be predicted in various ways. An early indication of a

neg: Color vision an antagonistic way: red vs. green, blue vs. yellow, black vs. white. Both theories are now accepted as valid, describing different stages in visual physiology, visualized in the adjacent diagram. Green←→Magenta and Blue←→Yellow are scales with mutually exclusive boundaries. In the same way that there cannot exist a "slightly negative" positive number, a single eye cannot perceive a bluish-yellow or a reddish-green. A range of wavelengths of light stimulates each of these receptor types to varying degrees. Yellowish-green light, for example, stimulates both L and M cones equally strongly, but only stimulates S-cones weakly. Red light, on the other hand,

neg: Cat cognitive support diets deficiency but can be hereditary as well. However, because of improved nutritional health in recent years, the incidence of hereditary cases of this disease are seen less frequently. The retina, a thin layer of tissue in the back of the eye, is the structure affected by this disorder. This structure receives the light gathered and focused from the lens. It essentially take light and converts it into electrical nerve signals that the brain interprets as vision. The retina contains rods and cones which are photo-receptors that help the animal see (rods) and see certain colours (cones). Retinal degeneration can be

neg: Traffic cone similar function. Traffic cones are typically used outdoors during road work or other situations requiring traffic redirection or advance warning of hazards or dangers, or the prevention of traffic. Traffic cones are also used to mark where children are playing or to block off an area. For night time use or low-light situations traffic cones are usually fitted with a retroreflective sleeve to increase visibility. On occasion, traffic cones may also be fitted with flashing lights for the same reason. In the US, cones are required by the US Federal Highway Administration's "Manual on Uniform Traffic Control Devices" (MUTCD) to

neg: Color color-sensing cones are missing or less responsive than normal to incoming light, that person can distinguish fewer colors and is said to be "color deficient" or "color blind" (though this latter term can be misleading; almost all color deficient individuals can distinguish at least some colors). Some kinds of color deficiency are caused by anomalies in the number or nature of cones in the retina. Others (like "central" or "cortical" "achromatopsia") are caused by neural anomalies in those parts of the brain where visual processing takes place. While most humans are "trichromatic" (having three types of color receptors), many animals,

neg: Widdringtonia four rows along the twigs, while the juvenile needle leaves are arranged spirally. The male cones are small, 3–6 mm long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, maturing in 18–20 months to 2–3 cm long and wide, globular to ovoid, with four, thick, woody scales, arranged in two opposite pairs. The cones mostly remain closed on the trees for many years, opening only after being scorched by a wildfire; this then releases the seeds to grow on the newly cleared burnt ground. In "W. whytei" the cones open soon after

neg: Catfish catches. There are also reports in the region of deaths from being swallowed by these fish. In many catfish, the "humeral process" is a bony process extending backward from the pectoral girdle immediately above the base of the pectoral fin. It lies beneath the skin where its outline may be determined by dissecting the skin or probing with a needle. The retina of catfish are composed of single cones and large rods. Many catfish have a tapetum lucidum which may help enhance photon capture and increase low-light sensitivity. Double cones, though present in most teleosts, are absent from catfish. The