White Flash Research Articles

Revenge

Revenge Wang Zengqi (bio) Translated by Xujun Eberlein (bio) An avenger should not break his sword. A jealous man should not complain of a tile falling off the roof. —Zhaungzi (369–280 bc) A white candle; a half jar of honey. The honey is not in his view right now. The honey is in the jar; he is sitting on the low bed. But his senses are filled with honey, dense, thick. The bile does not rise into his throat. He has a good appetite. He hasn’t vomited many times in his whole life. A whole life. How long is a whole life? Have I had a whole life now? Doesn’t matter. This is a very common pet phrase. Everybody says, “In my whole life . . .” Like this monk—monks must often eat this kind of wild honey. His eyes narrow a bit, because the candlelight jumps, and a heap of shadows jumps, too. He smiles once: in his mind he has come up with a name for the monk, “the honey monk.” This is no wonder, because the words “a whole life” hide behind honey and monk. Tomorrow when I say goodbye, what would he do if I really call him that? Well, now the monk has a name, what about me? What would he call me? It wouldn’t be “the sword guest” (he noticed that the monk saw his sword at once), would it? The honey—now it comes back to him that he heard bees buzzing all the way here. Yes, bees. Lots of bees (they made the whole mountain drift with their buzzing). Even now the residual sound remains in his ears. From here I began my tonight, and my tomorrow will continue from here. Life really is hard to say. He suddenly realizes, from the sound of the bees, that it is autumn. He feels unburdened and refreshed. That’s right, at the moment one word is written in the whole world: autumn. He imagines the monk looking for bees. A big field of wildflowers. The monk stands in front of the field of flowers; it really is beautiful. The monk is picking flowers. There are flowers in the copper bowl in the hall, they bloom very nicely, drifting, as if a cloud of fog is rising from the bowl. He likes this monk. The monk is going out. He holds one hand up, walking backward a few steps, casually yet considerately. Monk, you must have saluted like this, completely at ease, numerous times by now. The monk puts down the candle and says a few words, something about the temple being too remote to offer guests better treats; the mountain is high, wind big, weather cold, and you should rest early. He hears it even if the monk does not speak. The monk has spoken, but he isn’t listening. He just looks at the monk. He rises to show politeness. The monk drifts away, his sleeves flowing, like a big butterfly. [End Page 119] He can’t draw the monk’s appearance in his mind. He thinks that, had the monk not shaved his head, he would have a head of nice white hair. A head of shining white hair flashes in his mind. A white-haired monk. He is thinking of his white-haired mother. The night comes so fast on the mountain! Once the sun sets, every moving thing rests. It is so quiet. While he was on the way here, he already felt quietness. But inside the mountains is quite different from on the road. When he entered the little village, there were sounds of children reading books in school, horse bells, and flails knocking on beanstalks. On the little trail, fresh cow dung effused warm steam. White clouds slowly moved past haystacks. A little girl with braids was dressed in a silvery red jersey . . . but all the things that would have been used for describing stillness now indicate movement. He had even thought of becoming a peddler to add a bit of sound to the village, but at this moment, amongst a thousand mountains, he mustn’t wave a peddler’s rattle-drum. A peddler’s...

Poet In The Pit: Slayer, Heavy Metal, and The Limits Of Poetry

Poet In The Pit:Slayer, Heavy Metal, and The Limits Of Poetry Ernest Hilbert (bio) I'm walking down Walnut Street in Philadelphia on my lunch break when I develop a pronounced limp. Welts and bruises have risen on my biceps and upper legs. A 46-year-old antiquarian bookseller who works on the top floor of the art deco Sun Oil Building, I have received hundreds of severe blows, the kind that shake the brain and rattle the spine. About 20 hours ago I waded into the middle of a massive mosh pit at a Slayer concert. My first Slayer concert was 30 years ago, and my ability to take punishment, and to heal from it, has waned. I'll be restored in a few days. After the next concert, the next summer, I'll be in recovery for nearly a month, but today I feel good. I am triumphant. What is a mosh pit? How does one explain it to someone who has never even seen one, much less been pulled into the maelstrom? It compares with very few other experiences. Merriam-Webster offers a staid definition of "an area in front of a stage where very physical and rough dancing takes place at a rock concert." Wikipedia is a bit more helpful: a style of dance in which participants push or slam into each other, typically performed to "aggressive" live music. It originated in the hardcore punk scenes of California and Washington, D.C., in the early 1980s, thereafter spreading from hardcore to other forms of punk rock as well as thrash metal. Better. As often, Urban Dictionary is even more helpful, illustrating a number of types of pit, including the Closed Pit ("Tight, hard to move and hard to breathe"), Open Pit ("You can pick a target and reach them, [End Page 358] throw them across the floor, punch them, barge them [sic]"), and Circle Pit ("Run around in an empty circle punching those on the outside of the circle and pushing the runner in front until he either leaves or falls to be trodden on …"). Though the etymology of "mosh" remains somewhat murky, Merriam-Webster traces the word to 1983, possibly an "alteration of mash," as it appeared in early hardcore zines. The band Anthrax was instrumental in popularizing the term for larger audiences. A Slayer pit is a mixture of these three principal types, unfolding in a completely unpredictable and dangerous manner in pitch darkness split by blinding white flashes from strobe lights. The closest non-concert experience I've had was during a protest march in 2003 that rammed me up against police barricades in Manhattan with a crush of thousands behind who were unaware that those in the vanguard were trapped at the barriers. Your own body becomes lost in the animal movement of a great mass. Panic sets in at first when you are crushed; it gets hard to breathe, you lose your footing and find yourself lifted off the ground by the pressure of crowded bodies. It is also invigorating. Metal shows always have this insane press, closer to the stage. The pit is a more merciless environment precisely because you can move. You must move. It is impossible to explain why anyone would willingly choose to enter such a situation at all, much less for an hour or more. Heroic quantities of beer, gallons of it, help to produce the correct attitude, of course. Also, the volume and intensity of the music heightens the corporal instincts. The fiercest thrill arrives from the combination of total physical exertion accompanied by sometimes total loss of bodily control. Slayer creates these conditions on every occasion, quickly and reliably. ________ Recently, Slayer performed at the end of a two-day hard rock and heavy metal festival called Rock Allegiance Fest, held at Talen Energy Stadium in Chester, Pennsylvania. The day is sweltering, hellishly humid. For the festival, the soccer field itself is opened up for the audience. This allows for far more bodies than the 18,500 seats would [End Page 359] suggest. Inside the stadium, the well-tended grass of the playing field is preserved from damage by an UltraDeck synthetic turf...

The Falling Out

The Falling Out Drew McCutchen (bio) Rocky didn’t want to spend his Christmas morning driving to Bellingham. He didn’t want to fight about it either. If he wanted to fight, he would have reminded Olivia that his parents were most certainly dead, and that this should exempt him from having to spend his Christmas with her father. But Olivia had already warned him that morning with a tightened raise of her eyebrows, the universal sign for “don’t fuck with me,” when he hesitated to pack the van. Now here they were, cruising up I-5, heading north. Their van lurched over a bump and Jack cried from the back seat. Olivia unbuckled her seatbelt and turned back to soothe their son. “Do you have to drive so fast?” Rocky moved his foot side-to-side, trying to knock feeling back into his toes. “I just want to get there early enough to leave without a scene,” he lied. Olivia turned back to her seat. “Well maybe if we visited more often he wouldn’t make a scene.” Rocky sighed and ran a hand through his thinning hair. His counselor, Dr. Jacobs, who Rocky met for an hour every Wednesday on Olivia’s insistence, told him that it was important to fight, to be invested. “He thinks family is very important,” she said. “He thinks family is very important now.” Rocky winced at his own words, feeling himself drawn into an argument. “What is—” Olivia stopped. They crested the hill to the interchange with I-90, and the desolation spread out before them. The foothills had protected many areas from the blasts, but here, in the Skagit Valley, the cities had been exposed to the brunt of the initial heat waves. The buildings that still stood were twisted, crippled at their support beams. The billboards, burned down to their skeletons, gnarled backwards like broken bones. The tree line in the distance a black backdrop, and the river, its slow meandering trail through the city, now ran gray with ash and sludge. They remained silent while they drove through this newly formed black desert, as stalled vehicles, roasted from the bombings, lined the freeway’s shoulders for miles. After the blasts, the government had tried to clear the roads, towing the charred vehicles out of sight, stacking the cars into towers of black steel. But the fervor to right the world ran short of the work to be done, and they had pushed the remaining rolling coffins onto the shoulder and called it good enough. Now the cars stretched on both sides, whole families still entombed inside almost two years later, their ashes sitting upright, waiting on a destination. Blast cracks spidered across the freeway’s bleached blacktop. Their van bumped over the buckled cement. Jack started crying again, and Olivia turned back to him. The black and pink ocean of her lesion raged against the delicate skin of her neck, the waves reaching up her cheek. At first she had let Rocky trace the wound with his fingers, riding the ridge between the scarring and the skin, honoring her new body. But then Jack had been born and she had stopped letting him touch her. And eventually Rocky had stopped trying. [End Page 132] “Can you please slow down!” Rocky didn’t respond, but instead kicked his foot against the floor. He didn’t want to tell Olivia about the hole in his right foot. The one that had started at the heel where he had nicked it on a nail during one of his secret trips to his charred childhood home. He didn’t want to tell her that the wound had scabbed over but refused to heal, that a sore had appeared, filled with fluid, popped, and dribbled orange ooze. The injury was slowly excavating the feeling from his foot, and now it sat like a brick on the gas pedal. He didn’t want to tell her that his foot wasn’t going to get better. This would just lead to the same useless fight. “It’s the cruise control. It edges up,” he lied again. He scanned his mirrors for the white flash of...

Electroretinographic Assessment of Inner Retinal Signaling in the Isolated and Superfused Murine Retina

ABSTRACTPurpose: Longer-lasting electroretinographic recordings of the isolated murine retina were initially achieved by modification of a phosphate-buffered nutrient solution originally developed for the bovine retina. During experiments with a more sensitive mouse retina, apparent model-specific limitations were addressed and improvements were analyzed for their contribution to an optimized full electroretinogram (ERG).Material and methods: Retinas were isolated from dark-adapted mice, transferred to a recording chamber and superfused with different solutions. Scotopic and photopic ERGs were recorded with white flashes every 3 minutes. The phosphate buffer (Sickel-medium) originally used was replaced by a carbonate-based system (Ames-medium), the pH of which was adjusted to 7.7–7.8. Moreover, addition of 0.1 mM BaCl2 was investigated to reduce b-wave contamination by the slow PIII component typically present in the murine ERG.Results: B-wave amplitudes were increased by the pH-shift (pH 7.4 to pH 7.7) from 22.9 ± 1.9 µV to 37.5 ± 2.5 µV. Improved b-wave responses were also achieved by adding small amounts of Ba2+ (100 µM), which selectively suppressed slow PIII components, thereby unmasking more of the true b-wave amplitude (100.0% with vs. 22.2 ± 10.7% without Ba2+). Ames medium lacking amino acids and vitamins was unable to maintain retinal signaling, as evident in a reversible decrease of the b-wave to 31.8 ± 3.9% of its amplitude in complete Ames medium.Conclusions: Our findings provide optimized conditions for ex vivo ERGs from the murine retina and suggest that careful application of Ba2+ supports reliable isolation of b-wave responses in mice. Under our recording conditions, murine retinas show reproducible ERGs for up to six hours.

Noninvasive hemoglobin measurement using unmodified smartphone camera and white flash.

We show that a mobile phone can measure hemoglobin levels using the built-in RGB camera and white LED without modification. Prior work has demonstrated that a smartphone using the built-in RGB camera with the aid of visible and IR lights can achieve a Pearson correlation results between 0.69-0.82 and an RMSE value between 1.26-1.56 g/dL. Our system builds upon the prior work and demonstrates that with only the built-in white LED, the estimation of hemoglobin level has a Pearson correlation of 0.62 with an RMSE of 1.27 g/dL. This extension work demonstrates that it is feasible to measure hemoglobin without using an IR source.

Response Characteristics and Retinal Origin of the Photopic Negative Response of the Electroretinogram in Dogs

ABSTRACTPurpose: To investigate the response characteristics and retinal origin of the photopic negative response (PhNR) of the electroretinograms (ERGs) in dogs.Methods: Photopic ERGs were elicited by white flash stimuli of different intensities under a steady white background illumination in four anesthetized dogs. These ERGs were also recorded in the same manner after intravitreal injection of tetrodotoxin (TTX). Additionally, retinal localization of voltage-gated sodium channel Nav 1.6 was assessed by immunohistochemistry.Results: The amplitude of the a-wave and the PhNR was increased as the stimulus intensity was raised, while the amplitude of the b-wave was peaked at the moderate stimulus intensity of 3.09 cd·s/m2. TTX greatly attenuated the PhNR, while the reduction in the b-waves and a-wave was mild or insignificant. Nav 1.6-expression was specifically detected on the retinal ganglion cells (RGCs).Conclusions: Our results are consistent with the PhNR primarily derived from the inner retina including RGCs in dogs, suggesting that the PhNR can be used to monitor function of these retinal components in dogs.

Ectopic Expression of Mouse Melanopsin in Drosophila Photoreceptors Reveals Fast Response Kinetics and Persistent Dark Excitation

The intrinsically photosensitive M1 retinal ganglion cells (ipRGC) initiate non-image-forming light-dependent activities and express the melanopsin (OPN4) photopigment. Several features of ipRGC photosensitivity are characteristic of fly photoreceptors. However, the light response kinetics of ipRGC is much slower due to unknown reasons. Here we used transgenic Drosophila, in which the mouse OPN4 replaced the native Rh1 photopigment of Drosophila R1-6 photoreceptors, resulting in deformed rhabdomeric structure. Immunocytochemistry revealed OPN4 expression at the base of the rhabdomeres, mainly at the rhabdomeral stalk. Measurements of the early receptor current, a linear manifestation of photopigment activation, indicated large expression of OPN4 in the plasma membrane. Comparing the early receptor current amplitude and action spectra between WT and the Opn4-expressing Drosophila further indicated that large quantities of a blue absorbing photopigment were expressed, having a dark stable blue intermediate state. Strikingly, the light-induced current of the Opn4-expressing fly photoreceptors was ∼40-fold faster than that of ipRGC. Furthermore, an intense white flash induced a small amplitude prolonged dark current composed of discrete unitary currents similar to the Drosophila single photon responses. The induction of prolonged dark currents by intense blue light could be suppressed by a following intense green light, suggesting induction and suppression of prolonged depolarizing afterpotential. This is the first demonstration of heterologous functional expression of mammalian OPN4 in the genetically emendable Drosophila photoreceptors. Moreover, the fast OPN4-activated ionic current of Drosophila photoreceptors relative to that of mouse ipRGC, indicates that the slow light response of ipRGC does not arise from an intrinsic property of melanopsin.

Genetic algorithm for optimization of models of the early stages in the visual system

Automated parameter search methods are commonly used to optimize neuron models. A more challenging task is to fit models of neural systems since the model response is determined by both intrinsic properties of neurons and the neural wiring and architecture of the network. Neural records of cells in the visual system are often analyzed in terms of the cell’s receptive field and its temporal response. This type of data requires a finer point-by-point comparison of response traces between the simulated output and the recorded data. To address these issues, we applied a genetic algorithm optimization in conjunction with a multiobjective fitness function and a population-based error metric. Two different models of the early stages in the visual system were fitted to electrophysiological recordings and results from a modeling study, respectively. The first one is a model of cone photoreceptors and horizontal cells that reproduces adaptation to the mean light intensity in the retina. A multiobjective fitness function based on the normalized root-mean-square error (NRMSE) and a shape error descriptor captures high-frequency oscillations in the impulse response to uniform white flashes. The second one is a large-scale model of the thalamocortical system that accounts for the slow rhythms observed during sleep. An error metric of the population neural activity is used in this case. We argue that the optimization framework proposed in this paper could serve as a useful tool for parameter fitting of neuron models and large-scale models in the visual system pathway.

A Search for Meteoroid Lunar Impact Generated Electromagnetic Pulses

Lunar white light flashes associated with meteoroid impacts are now regularly observed using modest optical instrumentation. In this paper, we hypothesize that the developing, optically-dense hot ejecta cloud associated with these hypervelocity impacts also produce an associated complex plasma component that rapidly evolves resulting in a highly-transient electro magnetic pulse (EMP) in the VHF/UHF spectral region. Discovery of the characteristics and event frequency of impact EMPs would prove interesting to meteoroid flux and complex plasma physics studies especially if EMPs from the same event are detected from at least two locations on the Earth with relative delays appropriate to the propagation paths. We describe a prototype observational search, conducted in May 2014, for meteoroid lunar-impact EMPs that was conducted using simultaneous, overlapping-band, UHF radio observations at the Arecibo (AO; Puerto Rico) and Haystack (HO, Massachusetts, USA) Observatories. Monostatic/bistatic lunar radar imaging observations were also performed with HO transmitting and HO/AO receiving to confirm tracking, the net delay, and the pointing/timing ephemeris at both observatories. Signal analysis was performed using time–frequency signal processing techniques. Although, we did not conclusively identify EMP returns, this search detected possible EMPs and we have confirmed the search paradigm and established the sensitivity of the AO–HO system in detecting the hypothesized events. We have also characterized the difficult radio-frequency interference environment surrounding these UHF observations. We discuss the wide range of terrestrial-origin, Moon-bounce signals that were observed which additionally validate the observational technique. Further observations are contemplated.

Effect of shorter dark adaptation on ISCEV standard DA 0.01 and DA 3 skin ERGs in healthy adults.

To quantify dark-adapted (DA) skin ERG changes during 20min of dark adaptation. Sixteen healthy adult subjects were dark-adapted for 20min during which ISCEV standard dim (0.01photcdsm(-2)) white flash ERGs were recorded at 1, 2, 3, 4, 5, 10, 15 and 20min, and bright (3photcdsm(-2)) white ERGs were recorded at 2, 5, 10, 15 and 20min without mydriasis and using skin electrodes. Amplitudes and peak times were normalised to 20min values. Halving dark adaptation from 20 to 10min had no measureable effect on the DA 3 ERG and caused a 10% amplitude loss (range 0-23%) only for the DA 0.01 ERG b-wave amplitude. No significant peak time changes resulted, nor increased parameter variability. Reducing dark adaptation from 20 to 10min or even less has an effect on only DA 0.01 ERGs. Shorter dark adaptation than 20min may not compromise the clinical utility of the ERG providing clinics adhere to the usual standards of adequate reference data.

Normative Study of the Full Field Electroretinogram in Cats: a Fast Dark-Adaptation Curve

1.1.Purpose:The aim of the present study is to standardize the normal values of each component of the signals that comprise the ERG of normal cats, in accordance with the ISCEV protocol currently recommended in clinical examinations, for its relevance as a diagnosis method to assess retinal function and detect lesions in their outer layers. 1.2.Methods:Ten healthy domestic cats were used for this study. The ERG was randomly recorded using a Nihon Kohden system. We registered a series of light and dark-adapted ERGs. 1.3.Results:The mean amplitude of the b wave in photopic conditions with bright white flash is 180,0 μV, while in scotopic environment we found a mean amplitude of 600,0 μV for the b wave, most of which was divided into two components (b1 and b2).? Conclusion:The cat ERG has a particular profile, with a fast dark-adaptation response. This normative study will allow the comparison of data recorded by different research groups, and enable a more complete use of the ERG as a tool for future studies on diagnosis and treatments of diseases affecting each retina layer in particular.

Photonic welding of ultra-long copper nanowire network for flexible transparent electrodes using white flash light sintering

A schematic representation of the white flash light welding process of a percolated Cu NW network electrode.

Atomic Screen Test

Atomic Screen Test Jennifer Fay (bio) Atomic Disappointment On April 22, 1952 Americans watched the first televised live broadcast of an atomic explosion. A relay of cables and microwave transmissions from the Yucca Flats Proving Grounds to the Los Angeles KTLA station brought the blast into millions of living rooms using the latest and most innovative telecast technology. Yet, as the countdown commenced, in place of the much-anticipated sublimity of scientific triumph, viewers were instead witness to a kind of televisual failure or electronic gag. Just before the blast, the crew lost microwave power and had to shift the signal to the even more remote back-up camera some forty miles away. The greater challenge, however, was the explosion itself. At the moment of detonation, the camera, overwhelmed by atomic light, transcribed nuclear fission into a tiny white dot in the middle of a black sphere, as if it were the television and not the desert warming up. The image momentarily flickered only to fade into indistinct grey scales when the signature mushroom cloud formed.1 New York Times television critic Jack Gould mused that during the broadcast it seemed as if “electronic gremlins had taken charge.” At its most dramatic, the explosion appeared like “a big doughnut” in the sky before morphing into a “more conventional white puff of cotton.” “When most of the excitement was over, of course, the picture came in much better.” To make matters less interesting, the broadcast ended before American troops marched to ground zero, what would surely have been a recordable and exciting display of wargame maneuvering. For most viewers, writes Gould, “everything happened so fast—and so far away from the camera—that as a visual spectacle on TV the blast was a little anti-climatic.”2 [End Page 611] Networks were flooded with complaints after the fact. TV set owners, presuming the problem was a matter of fine tuning, attended more to the technology than the content of the broadcast itself, frantically changing channels and manipulating the horizontal and vertical hold knobs on their receivers. For such tinkerers, Gould speculates, “the atomic bomb meant geometric swirls, diagonal bars and their own large-screen trauma” (“Radio and Television,” 35). In Los Angeles, viewers could either look at the heavens or watch their TV sets. According to the Los Angeles Times, both options were disappointing. Gazing skyward at H-hour, one saw nothing but the “Southland morning haze”; on the tube, “a big black circle, and in the center a small white flash. Then slowly, like a giant rising from the earth, the fantastic mushroom cloud—a jagged lollipop on a narrow stick.”3 One hears in these descriptions the diminution of atomic expectation. Television, that centerpiece of the American living room, was a technology of counter-sublime abstraction, or worse, perhaps, domesticating the forces of nuclearism into cartoon figures of big donuts, jagged lollipops, and conventional white puffs of cotton. The Times assured readers that all stations would soon broadcast the extensive newsreel footage, for only emulsified film could translate television’s black blobs and squiggly lines into the event of nuclear detonation. But it could do so only belatedly.4 The problem of atomic disappointment predated this televisual blunder. According to Bob Mielke, the US Signal Corps deemed as only adequate the film coverage of the Trinity test, but “there was less satisfaction” with the bombing footage from Hiroshima and Nagasaki.5 In comparison to the eviscerating effects of the bomb on the ground, the image of the explosion itself was distant, brief, and shaky.6 To compensate for the paucity of this visual archive, the United States government amassed one and half million feet of film to document the 1946 tests, Operation Crossroads, at Bikini Atoll in the Marshall Islands, leading to a worldwide shortage of film stock and producing the most stunning images of mass destruction (Mielke, “Rhetoric and Ideology,” 29). Here, too the military was wracked by nuclear performance anxiety. The stated purpose of Operation Crossroads was to measure the impact of atomic explosions on naval vessels. Quoted in the New York Times, one scientist cautioned that, however spectacular the explosion, “damage to a large fleet spread...

Emission Factors for Aerial Pyrotechnics and Use in Assessing Environmental Impact of Firework Displays: Case Study from Malta

AbstractThe measurement of emission factors for PM10 for different aerial (display) firework devices, namely, flash crackers, stars, blast charges, and fuse matches as produced in Malta are reported herein. Additionally, the content in fireworks‐generated PM10 of Al, Ba, Cu, Sr, and Sb is determined. PM10 values were as follows in kg per kg composition: blast charges 0.054; flash crackers 0.43; stars 0.175 (red); 0.176 (blue); 0.254 (green); 0.123 (white); fuse matches 0.204. The metal content in PM10 from fireworks (in kg per kg composition) depends on the type of device burnt, with green stars producing Ba at 0.0553, blue stars Cu at 0.0123, and red stars Sr at 0.0057. White stars and flash crackers containing Sb2S3 produce Sb at 0.0395 and 0.1083 kg per kg composition, respectively. We used these emission factors and trade information on chemicals used for the manufacture of pyrotechnics in Malta to estimate the total load of PM10 and associated metalliferous content released to the atmosphere from aerial fireworks displays. In 2007, PM10 emissions amounted to about 37 t and metal loads (in kg) were Al (2193), Ba (1161), Sb (504), Cu (331), and Sr (142). The data and modeling approach presented herein illustrates a general methodology for the assessment of environmental risk from display fireworks especially when more specific information is unavailable.

ANALYSIS OF A CONFOCAL SCANNING LASER OPHTHALMOSCOPE NONCONTACT ULTRA-WIDE FIELD LENS SYSTEM IN RETINAL AND CHOROIDAL DISEASE.

Espina, Mark P. MD; Arcinue, Cheryl A. MD; Ma, Feiyan MD; Camacho, Natalia MD; Bartsch, Dirk-Uwe G. PhD; Freeman, William R. MD Author Information

Can camera trapping be used to accurately survey and monitor the Hastings River mouse (Pseudomys oralis)?

Camera trapping is increasingly recognised as a survey tool akin to conventional small mammal survey methods such as Elliott trapping. While there are many cost and resource advantages of using camera traps, their adoption should not compromise scientific rigour. Rodents are a common element of most small mammal surveys. In 2010 we deployed camera traps to measure whether the endangered Hastings River mouse (Pseudomys oralis) could be detected and identified with an acceptable level of precision by camera traps when similar-looking sympatric small mammals were present. A comparison of three camera trap models revealed that camera traps can detect a wide range of small mammals, although white flash colour photography was necessary to capture characteristic features of morphology. However, the accurate identification of some small mammals, including P. oralis, was problematic; we conclude therefore that camera traps alone are not appropriate for P. oralis surveys, even though they might at times successfully detect them. We discuss the need for refinement of the methodology, further testing of camera trap technology, and the development of computer-assisted techniques to overcome problems associated with accurate species identification.

Three family cases with Retinitis pigmentosa rod‐cone dystrophy with autosomal dominant inheritance

PurposeThree family cases with Retinitis pigmentosa (RP) rod‐cone dystrophy with autosomal dominant inheritance according to American Academy of Ophthalmology classification were diagnosed and studied: the grandmother G. D., 83 years old; the son A.D., 61 years old and granddaughter A.B., 27 years old.MethodsThe diagnosis was confirmed clinically, ERG, OCT, Angiography, (with colour tests) ATL, Ishihara table and Rabkin chart, All color Anomaloscope IF‐2 TOMEY, Test 28 HUE de Roth Farnsworth‐Munsell, with kinetic Kugel perimeter and automated Humphrey perimeter using the SITA‐Fast computerized perimetric threshold strategy.ResultsDuring the photopic test with ERG, there was observed retinogram with normal morphology and polarity but with drastic decline of the amplitude by 50 mV on average. In the process of dark adaptation, a decline of bioelectric activity was detected: from subnormal to non‐recording ERG during white and blue flashes at 30 Hz. In all of the three different generations’ cases, there was established reduction in residual bioelectric activity with the advancing of age of the patients with progressive degenerative RP disease. During the colour test, the grandmother and the father could read only ATL, which proves there was no acquired colour vision disorder. This is in confirmation to the autosomal dominant inheritance. In the process of anomaloscopic test and the colour tables and charts of Ishihara and Rabkin, as well as Test 28 HUE de Roth Farnsworth‐Munsell, the grandmother and the father were found to be with deuteranomaly. The granddaughter had a normal trichromacy. The perimetric tests showed concentric narrowing of the visual field to tubular vision.ConclusionsSerum for genetic tests was taken from the three family cases in order to confirm the diagnosis and administer a gene therapy.

Photopic negative response in diagnosis of glaucoma: an experimental study in glaucomatous rabbit model.

To determine whether the photopic negative response (PhNR) elicited by transient white flash on white background is characterizing for glaucoma model in rabbits. Glaucoma was induced in twelve rabbits by subconjunctival injection of 0.05 mL of betamethasone in right eyes (each 1 mL contain betamethasone dipropionate 5 mg and betamethasone sodium phosphate 2 mg).The intraocular pressure (IOP), electroretinogram (ERG) and visual evoked potential (VEP) were measured successively prior and on the 3, 7d, two weeks and four weeks postglaucoma induction. After four weeks, the animals were sacrificed and the globes were histopathologically examined. The IOP increased significantly after one week (P=0.0001), then it gradually returned to the control level. In ERG examination, the means of a and b wave amplitude and latency were not affected significantly. PhNR amplitude decreased significantly within one week (P=0.0001), but its latency was not affected significantly (P=0.132). The means of VEP latency and amplitude were significantly affected after two weeks and four weeks of glaucoma induction (P=0.0001 and 0.02, respectively). The histopathologic examination of the globes showed reduced number of cells in the retinal ganglion cell layer with multiple vacuoles in the retinal nerve fibre layer.There was significant positive correlation between ganglion cell layer cells and PhNR amplitude (r=0.8, P=0.002). The rise in IOP resulted in irreversible changes or incomplete recovery of VEP and PhNR amplitude. Both PhNR and VEP represented good additional tools in early diagnosis of glaucoma.

Short Communication: Contribution of Voltage-Gated Sodium Channels to the Rabbit Cone Electroretinograms

ABSTRACTPurpose: Although the rabbit eye is of a similar size to the human eye, our limited understanding of the differences in retinal physiology to other species hinders its use in retinal research. The role of voltage-gated sodium channels (Nav) in the propagation of excitatory potentials along bipolar cells remains unclear, as conflicting data have been reported in the rabbit. The present study assesses the relative contributions of Nav to the scotopic and photopic flash ERGs as well as the wavelength-dependence of Nav blockade on the rabbit flicker ERG.Materials and Methods: Tetrodotoxin (TTX, 1 μM) was injected into the vitreous cavity of Chinchilla bastard rabbits. Scotopic ERGs were evoked by white flashes ranging from 10−5 to 10 cds m−2, photopic ERGs on a background of 25 cdm−2 using flash intensities of 0.032–25 cds m−2. Flicker ERGs (3–50 Hz) were elicited by blue, green and yellow stimuli at 2.34 cds m−2 on a white background of 30 cdm−2.Results: The a- and b-waves of the scotopic ERG were unaffected by intravitreal injection of the Nav blocker TTX. In contrast, the b-wave, but not the a-wave, of the photopic ERG was selectively blocked by TTX. The reduction by TTX of the flicker ERG was greater for blue than for green and yellow stimuli.Discussion: The data suggest that Nav selectively contribute to the generation of the photopic b-wave in the rabbit, indicating that they play an important role in the propagation of excitatory signals on bipolar cells in the cone, but not rod pathways. Importantly, the present study resolves conflicting previous reports into the role of Nav in the retinal function of the rabbit.

Stimulus characteristics affect assessment of pupil defects in amblyopia.

Amblyopes do not reliably show relative afferent pupillary defects with full-field stimulation, but amblyopia has cortical involvement; hence, stimuli that engage cortex may be able to reveal pupil defects in amblyopes. Pupillary responses were acquired with a binocular infrared pupillometer (RAPDx, Konan Medical USA, Irvine, CA) from 15 amblyopic subjects (anisometropic and small-angle strabismic) and 10 age-matched control subjects. Stimuli were a full-field white flash (330 cd/m) or a small (4 degrees) annulus at one of three contrast levels (0.3, 0.6, and 1.8) on a dim background (6.2 cd/m). Stimulus duration was 100 milliseconds, and the interstimulus duration was 2000 milliseconds. In all four stimulus conditions, the difference in percent contraction amplitude for right versus left eye stimulation was more variable across amblyopes than across control subjects. Amblyopic eyes did not show a specific deficit for the full-field flash. However, the mid-contrast (0.6) annulus stimulus revealed a deficit in the amblyopic eye, whereas the size of the deficit did not correlate with the type or depth of the amblyopia. Targets of appropriate pattern, brightness, and contrast that select for cortical contributions to the pupil response may be useful for eliciting pupil defects in amblyopic patients. Pupil analysis in this population could prove useful for diagnostic or prognostic value, for example, to determine which amblyopes will respond best to treatment.