The electric sense of elasmobranch fishes (sharks and rays) is an important sensory modality known to mediate the detection of bioelectric stimuli. Although the best known function for the use of the ...elasmobranch electric sense is prey detection, relatively few studies have investigated other possible biological functions. Here, we review recent studies that demonstrate the elasmobranch electrosensory system functions in a wide number of behavioral contexts including social, reproductive and anti-predator behaviors. Recent work on non-electrogenic stingrays demonstrates that the electric sense is used during reproduction and courtship for conspecific detection and localization. Electrogenic skates may use their electrosensory encoding capabilities and electric organ discharges for communication during social and reproductive interactions. The electric sense may also be used to detect and avoid predators during early life history stages in many elasmobranch species. Embryonic clearnose skates demonstrate a ventilatory freeze response when a weak low-frequency electric field is imposed upon the egg capsule. Peak frequency sensitivity of the peripheral electrosensory system in embryonic skates matches the low frequencies of phasic electric stimuli produced by natural fish egg-predators. Neurophysiology experiments reveal that electrosensory tuning changes across the life history of a species and also seasonally due to steroid hormone changes during the reproductive season. We argue that the ontogenetic and seasonal variation in electrosensory tuning represent an adaptive electrosensory plasticity that may be common to many elasmobranchs to enhance an individual's fitness throughout its life history.
The development of Shark Chaser by the U.S. Navy during World War II was the first serious effort to develop a chemical shark repellent. In the decade following the war reports of Shark Chaser ...ineffectiveness led the Office of Naval Research to search for a more efficacious shark repellent. After years without success, ONR eventually canceled the use of Shark Chaser and abandoned the search for a chemical shark repellent. In the early 1970s, interest in chemical shark repellents was renewed by the discovery of pardaxin, a natural shark repellent secreted by the Red Sea Moses sole, Pardachirus marmoratus. The surfactant-like nature of pardaxin led investigators to test the potential of various surfactants as repellents. Subsequent studies indicated that the shark repellent efficacy of the effective alkyl sulfate surfactants was due to their hydrophobic nature. Here we report tests conducted on juvenile swell sharks, Cephaloscyllium ventriosum, to determine if the noxious quality of alkyl sulfates is affected by surfactant hydrophobicity carbon chain length and ethylene oxide (EO) groups and counterions. Our results indicate that the aversive response of sharks to alkyl sulfate surfactants increases with carbon chain length from octyl to dodecyl, decreases with the addition of EO groups and is not affected by counterions. This study confirms that dodecyl sulfate is the most effective surfactant shark repellent, but it does not meet the Navy's potency requirement for a nondirectional surrounding-cloud type repellent of 100 parts per billion (0.1 mu g ml super(-1)). Thus, dodecyl sulfate is only practical as a directional repellent such as in a squirt application. Future research should test the action of alkyl sulfates on cell membranes, the potential of other biotoxic agents, and semiochemicals in the search for an effective chemical shark repellent.
Adult stingrays use their ampullary electroreceptors to detect prey and locate mates, but the response properties and function of their electrosensory system in the pre-adult stages are unknown. We ...examined the response properties of Atlantic stingray (Dasyatis sabina) electrosensory primary afferent neurons through ontogeny to determine whether encoding of electrosensory information changes with age, and how it relates to the ontogenetic encoding of biologically relevant electric stimuli. We show that during development electrosensory primary afferents increase resting discharge regularity, show an upward shift in best frequency (BF), an increase in neural sensitivity, and a decrease in bandpass. These ontogenetic changes in the response properties of the stingray electrosense are consistent with sensory adaptations to enhance the avoidance of large predators as young, and increase the location of prey and mates as adults.
Ampullary electroreceptor systems in fishes and aquatic amphibians are known to function in prey localization by the movement of the animal through a weak do field produced by their prey. The round ...stingray produces an electric field with a complex geometry that is modulated rhythmically by movements of the spiracles and gill slits during ventilation. This weak stimulus is used in the field by reproductively active male stingrays to locate mates, and also by female rays to locate buried consexuals. Electrosensory primary afferent neurons are most sensitive to stimuli that vary sinusoidally at the same frequency as the natural respiratory movements. The match between primary afferent frequency sensitivity and the ventilatory phasic signals produced by conspecifics indicates that the electrosensory system serves an important biological function in the social behavior of elasmobranchs.
Acoustic communication is essential for the reproductive success of the plainfin midshipman fish (Porichthys notatus). During the breeding season, type I males use acoustic cues to advertise nest ...location to potential mates, creating an audible signal that attracts reproductive females. Type II (sneaker) males also likely use this social acoustic signal to find breeding pairs from which to steal fertilizations. Estrogen-induced changes in the auditory system of breeding females are thought to enhance neural encoding of the advertisement call, and recent anatomical data suggest the saccule (the main auditory end organ) as one possible target for this seasonal modulation. Here we describe saccular transcriptomes from all three sexual phenotypes (females, type I and II males) collected during the breeding season as a first step in understanding the mechanisms underlying sexual phenotype-specific and seasonal differences in auditory function. We used RNA-Seq on the Ion Torrent platform to create a combined transcriptome dataset containing over 79,000 assembled transcripts representing almost 9,000 unique annotated genes. These identified genes include several with known inner ear function and multiple steroid hormone receptors. Transcripts most closely matched to published genomes of nile tilapia and large yellow croaker, inconsistent with the phylogenetic relationship between these species but consistent with the importance of acoustic communication in their life-history strategies. We then compared the RNA-Seq results from the saccules of reproductive females with a separate transcriptome from the non-reproductive female phenotype and found over 700 differentially expressed transcripts, including members of the Wnt and Notch signaling pathways that mediate cell proliferation and hair cell addition in the inner ear. These data constitute a valuable resource for furthering our understanding of the molecular basis for peripheral auditory function as well as a range of future midshipman and cross-species comparative studies of the auditory periphery.
Acoustic communication plays an important role in the social behaviours of vocal teleost fishes in the family Batrachoididae (midshipman and toad fishes). The midshipman and toadfishes have become ...good models for investigating the neural and endocrine mechanisms of auditory perception and vocal production shared by all vertebrates (Bass and Lu 2006), in part, because the reproductive success of these batrachoidid fishes is highly dependent on acoustic communication. Recent neuroethological studies of acoustic communication in the plainfin midshipman fish (Porichthys notatus) have provided strong evidence for the related reproductive-state and steroid-dependent modulation of hearing sensitivity in this species that leads to enhanced coupling of sender and receiver in this communication system (Sisneros and Bass 2003; Sisneros et al. 2004a).
A terminology for in situ visualization and analysis systems Childs, Hank; Ahern, Sean D.; Ahrens, James ...
International journal of high performance computing applications/The international journal of high performance computing applications,
11/2020, Letnik:
34, Številka:
6
Journal Article
Recenzirano
Odprti dostop
The term “in situ processing” has evolved over the last decade to mean both a specific strategy for visualizing and analyzing data and an umbrella term for a processing paradigm. The resulting ...confusion makes it difficult for visualization and analysis scientists to communicate with each other and with their stakeholders. To address this problem, a group of over 50 experts convened with the goal of standardizing terminology. This paper summarizes their findings and proposes a new terminology for describing in situ systems. An important finding from this group was that in situ systems are best described via multiple, distinct axes: integration type, proximity, access, division of execution, operation controls, and output type. This paper discusses these axes, evaluates existing systems within the axes, and explores how currently used terms relate to the axes.
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