The importance of connectivity for freshwater organisms is widely recognised, yet in-stream barriers associated with population declines and increased risk of extinction remain globally ubiquitous. Despite their negat...
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The importance of connectivity for freshwater organisms is widely recognised, yet in-stream barriers associated with population declines and increased risk of extinction remain globally ubiquitous. Despite their negative consequences, these barriers can protect aquatic communities by limiting the spread of invasive species, leading to conflicting management goals in some regions. Selective fish passage is a solution for the conflicting goals of passing native, desirable species while restricting the spread of invasives. Approaches that can target groups of species sharing similar attributes (i.e. guilds) are likely to be more efficient than those that target species individually, particularly in taxonomically diverse systems. We explored the guild structure of 220 Great Lakes freshwater fishes based on morphological, phenological, physiological and behavioural attributes associated with passage and movement. We identified five distinct guilds as well as the attributes most important for defining these groupings: maximum total length, trophic level, relative eye size, spawning temperature, spawning season, presence/absence of ampullary electroreceptors and the presence/absence of hearing specialisations. The approaches outlined in this work can be generalised to enhance selective fish passage in aquatic ecosystems worldwide.
If one were to ask about the most significant figure to have influenced China, the answer would most certainly be Confucius. For a book that has exerted the most profound influence, the title most frequently mentioned...
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If one were to ask about the most significant figure to have influenced China, the answer would most certainly be Confucius. For a book that has exerted the most profound influence, the title most frequently mentioned would be the Analects of Confucius. The Analects records Confucius' remarks from over 2,500 years ago. However, the question must be raised: does this book still play a role in our lives today? Nowadays, there is a prevalent concern about how to study well, how to treat friends well, and how to understand oneself. The first passage of the Analects happens to address these issues.
This paper addresses the problem of developing an efficient fault-tolerant routing method for 2D mesh Network-on-Chips (NoCs) to realize dependable and high performance many core systems. Existing fault-tolerant routi...
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This paper addresses the problem of developing an efficient fault-tolerant routing method for 2D mesh Network-on-Chips (NoCs) to realize dependable and high performance many core systems. Existing fault-tolerant routing methods have two critical problems of high communication latency and low node utilization. Unlike almost all existing methods where packets always detour faulty nodes, we propose a novel and unique approach that packets can pass through faulty nodes. For this approach, we enhance the common NoC architecture by adding switches and links around each node and propose a fault-tolerant routing method with no virtual channels based on the well-known simple XY routing method. Simulation results show that the proposed method reduces average communication latency by about 97.1% compared with the existing method, without sacrificing fault-free nodes.
Wolbachia pipientis is a nearly ubiquitous, maternally transmitted bacterium that infects the germ line of insect hosts. Estimates are that Wolbachia infects 40 to 60% of insect species on the planet, making it one of...
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Wolbachia pipientis is a nearly ubiquitous, maternally transmitted bacterium that infects the germ line of insect hosts. Estimates are that Wolbachia infects 40 to 60% of insect species on the planet, making it one of the most prevalent infections on Earth. However, we know surprisingly little about the molecular mechanisms used by Wolbachia to infect its hosts. We passaged Wolbachia through normally restrictive Drosophila melanogaster hosts, bottlenecking Wolbachia through stochastic segregation while simultaneously selecting for mutants that could recolonize these previously restrictive hosts. Here, we show that Wolbachia alters its behavior when passaged through heterozygous mutant flies. After only three generations, Wolbachia was able to colonize the previously restrictive hosts at control titers. Additionally, the Wolbachia organisms passaged through heterozygous mutant D. melanogaster alter their pattern of tissue-specific Wsp protein production, suggesting a behavioral response to the host genotype. Using whole-genome resequencing, we identified the mutations accumulated by these lineages of Wolbachia and confirmed the existence and persistence of the mutations through clone library Sanger sequencing. Our results suggest that Wolbachia can quickly adapt to new host contexts, with genomic mutants arising after only two generations.
The passage of light through dispersion layers consisting of large weakly absorbing scatterers has been investigated. Measurements of the transmittance and the angular structure of scattered radiation have been made. ...
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The passage of light through dispersion layers consisting of large weakly absorbing scatterers has been investigated. Measurements of the transmittance and the angular structure of scattered radiation have been made. The dependence of these characteristics on the thickness and the concentration of scatterers has been analyzed. (C) 1999 Optical Society of America.
Populations of Pacific lamprey (Entosphenus tridentatus) in the Columbia River basin have declined and passage problems at dams are a contributing factor. We used radio telemetry to monitor the passage of adult Pacifi...
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Populations of Pacific lamprey (Entosphenus tridentatus) in the Columbia River basin have declined and passage problems at dams are a contributing factor. We used radio telemetry to monitor the passage of adult Pacific lampreys at the Willamette Falls Project (a hydroelectric dam integrated into a natural falls) on the Willamette River near Portland, Oregon. In 2005 and 2006, fish were captured at the Project. implanted with a radio tag, and released downstream. We tagged 136 lampreys in 2005 and 107 in 2006. Over 90% of the fish returned to the Project in 7 - 9 h and most were detected from 2000 - 2300 h. In 2005, 43 fish (34%) passed the dam via the fishway, with peak passage in August. No fish passed over the falls, but 13% ascended at least partway up the falls. In 2006. 24 fish (23%) passed the Project using the fishway, with most prior to 9 June when the powerhouse was off. Although 19 lampreys ascended the falls, only two passed via this route. The time for fish to pass through the fishway ranged from 4 - 74 h, depending on route. Many fish stayed in the tailrace for hours to almost a year and eventually moved downstream. Our results indicate that passage of lampreys at the Project is lower than that for lampreys at dams on the Columbia River. Low passage success may result from low river flows, impediments in fishways, delayed tagging effects, changing environmental conditions, or performance or behavioral constraints.
Little is known about the stopover biology of Spinus pinus (Pine Siskin) and other Fringillid birds during their irruptive movements into the US from boreal Canada. Here, we report on the passage timing, energetic con...
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Little is known about the stopover biology of Spinus pinus (Pine Siskin) and other Fringillid birds during their irruptive movements into the US from boreal Canada. Here, we report on the passage timing, energetic condition, and age distribution of 402 Pine Siskins that we captured during autumn stopovers in New Jersey in the irruption year of 2012. Pine Siskins passed through our study site for similar to 3 weeks and peaked in abundance between 9 and 12 October. More birds were juveniles than adults (54% v. 46%), although the difference was not significant. Juveniles were heavier than adults, but fat scores did not differ by age. Neither age group appeared to gain significant mass during the stopover. We encourage migration banding stations like ours that experience irruptions to report the information they collect and help improve our understanding of the migration biology and behavior of irruptive species.
passage extraction is an important component of passage retrieval. Sentence coherence and relevance is two factors mainly considered in the passage extraction. This paper proposes subsequence-based query-sensitive max...
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ISBN:
(纸本)9780769534886
passage extraction is an important component of passage retrieval. Sentence coherence and relevance is two factors mainly considered in the passage extraction. This paper proposes subsequence-based query-sensitive maximum cut algorithm for passage extraction. It incorporates the sentence coherence cut measure and sentence relevance cut measure into normalized cut criterion. And it uses suffix tree model for the text representation and subsequence-based sentence coherence and relevance measure. The experiment. results show that our method outperforms some of the existing methods.
Lower Granite Dam is the last dam that federally protected Snake River salmonids Oncorhynchus spp. must ascend during their spawning migration. The dam has an adult fish ladder equipped with a trapping system to facil...
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Lower Granite Dam is the last dam that federally protected Snake River salmonids Oncorhynchus spp. must ascend during their spawning migration. The dam has an adult fish ladder equipped with a trapping system to facilitate fisheries research and hatchery broodstock collection. There are three possible passage routes through the adult ladder: trapped, shunted, and free passage. During the adult trapping season, all fish must swim through 0.305-m shunt pipes outfitted with PIT tag arrays that allow the selection of fish for trapping. Selected fish use the "trapped" route and are kept in a holding area for up to 20 h before being sampled and returned to the ladder. Unselected fish use the "shunted" route and immediately resume upstream migration after swimming through the pipes. When the trap is not in operation, the shunted route is inaccessible, and all fish use the "free passage" route to ascend the ladder without additional impediment. In 2016, a temporary change in ladder operations permitted free passage for a portion of the trapping season. Our study used this rare opportunity to evaluate how different passage routes affect in-ladder transit time and upstream homing success for five salmonid stocks: Sockeye Salmon Oncorhynchus nerka;steelhead O. mykiss;and spring-, summer-, and fall-run Chinook Salmon O. tshawytscha. In 2016, only Sockeye Salmon and spring- and summer-run Chinook Salmon were given access to free passage, and we found evidence that free passage increased subsequent detection at natal sites upstream. An expanded analysis of shunted versus trapped fish during the years 2012-2016 found no difference in rates of detection to home tributaries by route of passage for any of the five fish stocks examined.
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