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Sample records for crabs uca annulipes

  1. Seasonal and Lunar Variation in the Emergence Time of a Population of Uca lactea annulipes (Milne-Edwards, 1837) at a Shore in Kuwait

    Science.gov (United States)

    Al-Musawi, Layla Isa; Wagner, Edgar

    2012-01-01

    This study monitored the endogenous emergence time of the fiddler crab Uca lactea annulipes (Milne-Edwards, 1837) in the field, for the first time, at an intertidal shore in Kuwait, from 1997 to 2001. The results revealed a significant cyclic change in the median emergence time as the season progressed from winter, through spring and summer, to autumn (.44,1.29,3.12, and 1.1 h prior to the dead-low tide, respectively). The data also revealed a significant shift in the median emergence time according to moon phase (2.27 h at new moon versus 2.56 h at full moon prior to the dead-low tide). (Author correspondence: l.almusawi@ropme.org) PMID:22489606

  2. Neurosecretion in the sinus gland of the fiddler crab, Uca pugnax.

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    Silverthorn, S U

    1975-12-29

    The ultrastructure of the sinus gland of the fiddler crab, Uca pugnax, was investigated and found to be similar to that in other crustaceans. Five types of neurosecretory axon terminals were tentatively identified on the basis of the size, shape, and electron density of granules within the axons. Release of neuro-secretory material appears to be by exocytosis.

  3. Why do Gull-billed Terns Gelochelidon nilotica feed on fiddler crabs Uca tangeri in Guinea-Bissau?

    NARCIS (Netherlands)

    Stienen, E.W.M.; Brenninkmeijer, A.; Klaassen, M.R.J.

    2008-01-01

    Wintering Gull-billed Terns Gelochelidon nilotica in Guinea Bissau mainly fed on Fiddler Crabs Uca tangeri and were occasionally seen feeding on fish and locusts. Fiddler crabs have a low energy content, requiring a large gross intake to meet daily energy demands. Fiddler crabs also have a low ratio

  4. EFFECTS OF SALT MARSH ALTOSID EXPOSURE ON FEMALE GROWTH & PRODUCTION IN GULF SAND FIDDLER CRAB, UCA PANACEA

    Science.gov (United States)

    Effects of Salt Marsh Altosid(R) Exposure on Female Growth and Reproduction in the Gulf Sand Fiddler Crab, Uca panacea (Abstract). Presented at the 62nd Annual Meeting of the Association of Southern Biologists, 4-7 July 2001, New Orleans, LA. 1 p.Adult Uca panacea were p...

  5. Experimental infections of Orchitophrya stellarum (Scuticociliata) in American blue crabs (Callinectes sapidus) and fiddler crabs (Uca minax).

    Science.gov (United States)

    Miller, Terrence L; Small, Hamish J; Peemoeller, Bhae-Jin; Gibbs, David A; Shields, Jeffrey D

    2013-11-01

    Outbreaks of an unidentified ciliate have occurred on several occasions in blue crabs from Chesapeake Bay held during winter months in flow-through systems. The parasite was initially thought to be Mesanophrys chesapeakensis, but molecular analysis identified it as Orchitophyra stellarum, a facultative parasite of sea stars (Asteroidea). We investigated the host-parasite association of O. stellarum in the blue crab host. Crabs were inoculated with the ciliate, or they were held in bath exposures after experimentally induced autotomy of limbs in order to determine potential mechanisms for infection. Crabs inoculated with the ciliate, or exposed to it after experimental autotomy, rapidly developed fatal infections. Crabs that were not experimentally injured, but were exposed to the ciliate, rarely developed infections; thus, indicating that the parasite requires a wound or break in the cuticle as a portal of entry. For comparative purposes, fiddler crabs, Uca minax, were inoculated with the ciliate in a dose-titration experiment. Low doses of the ciliate (10 per crab) were sometimes able to establish infections, but high intensity infections developed quickly at doses over 500 ciliates per crab. Chemotaxis studies were initiated to determine if the ciliate preferentially selected blue crab serum (BCS) over other nutrient sources. Cultures grown on medium with BCS or fetal bovine serum showed some conditioning in their selection for different media, but the outcome in choice experiments indicated that the ciliate was attracted to BCS and not seawater. Our findings indicate that O. stellarum is a facultative parasite of blue crabs. It can cause infections in exposed crabs at 10-15°C, but it requires a portal of entry for successful host invasion, and it may find injured hosts using chemotaxis.

  6. Spontaneous alternation and locomotor activity in three species of marine crabs: green crab (Carcinus maenas), blue crab (Callinectes sapidus), and fiddler crab (Uca pugnax).

    Science.gov (United States)

    Balcı, Fuat; Ramey-Balcı, Patricia A; Ruamps, Perrine

    2014-02-01

    Spontaneous alternation refers to the tendency of organisms to explore places that they have least recently visited. Our previous work showed that alternation performance of Carcinus maenas (invasive European green crab) was significantly higher than Callinectes sapidus (native blue crab), and chance level performance (Ramey, P. A., Teichman, E., Oleksiak, J., & Balcı, F. [2009]. Spontaneous alternation in marine crabs: Invasive versus native species. Behavioural Processes, 82, 51-55.). In the current study, we first tested the robustness of these findings in the absence of visual cues, longer test durations, and wider maze dimensions. These manipulations enabled us to determine whether these two crab species relied on the visual cues provided during the spontaneous alternation task in our prior work, and allowed for better characterization of their exploratory activity in the maze. Our original findings were reproduced in the present study under these new task conditions, suggesting no role for visual cues during alternation, and emphasizing the robustness and generalizability of the corresponding interspecies differences in alternation performance. We also tested whether the lower alternation performance of C. sapidus also applied to another native crab species, Uca pugnax (fiddler crab). Spontaneous alternation performance of U. pugnax was significantly lower than C. maenas but indistinguishable from C. sapidus. Finally, we examined whether the potentially higher inherent risk-sensitivity of C. sapidus could have contributed to their lower alternation performance by testing C. maenas in the presence of a larger natural predator (stressor). Higher risk sensitivity presumably induced by the stressor led to locomotor activity patterns that better resembled those of C. sapidus, however the resultant reduction in alternation performance was not statistically significant. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  7. CRUDE OIL TOXICITY TO THE FIDDLER CRABS UCA LONGISIGNALIS AND UCA PANACEA FROM THE NORTHERN GULF OF MEXICO: IMPACTS ON BIOTURBATION, OXIDATIVE STRESS AND HISTOLOGY OF THE HEPATOPANCREAS.

    Science.gov (United States)

    Franco, Marco E; Felgenhauer, Bruce E; Klerks, Paul L

    2017-09-11

    The intensive drilling and extraction of fossil fuels in the Gulf of Mexico result in a considerable risk for oil spills impacting its coastal ecosystems. Impacts are more likely to be far-reaching if the oil affects ecosystem engineers like fiddler crabs, whose activities modify biogeochemical processes in the sediment. The present study investigated effects of oil on the fiddler crabs Uca longisignalis and Uca panacea; important as ecosystem engineers and as prey for a wide variety of species. The present study used mesocosms and microcosms to investigate effects of crude oil on fiddler crab burrowing and to assess cellular and tissue damage by the oil. Fiddler crabs were exposed for periods of 5 or 10 days to oil concentrations up to 55 mg/cm(2) on the sediment surface. Their burrowing was delayed, their burrows were smaller, and they transported less sediment in the presence of oil. The hepatopancreas had elevated levels of oxidative stress and a higher abundance of blister cells that play a role in secretory processes. Interspecific differences were observed; most effects were strongest in U. panacea though burrowing was more strongly affected in U. longisignalis. The present study demonstrates that crude oil is likely to impact fiddler crabs and many species that depend on them for their diet or for the ecological changes that result from their burrowing. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. Phylogenetic patterns and the adaptive evolution of osmoregulation in fiddler crabs (Brachyura, Uca)

    Science.gov (United States)

    Faria, Samuel Coelho; Provete, Diogo Borges; Thurman, Carl Leo

    2017-01-01

    Salinity is the primary driver of osmoregulatory evolution in decapods, and may have influenced their diversification into different osmotic niches. In semi-terrestrial crabs, hyper-osmoregulatory ability favors sojourns into burrows and dilute media, and provides a safeguard against hemolymph dilution; hypo-osmoregulatory ability underlies emersion capability and a life more removed from water sources. However, most comparative studies have neglected the roles of the phylogenetic and environmental components of inter-specific physiological variation, hindering evaluation of phylogenetic patterns and the adaptive nature of osmoregulatory evolution. Semi-terrestrial fiddler crabs (Uca) inhabit fresh to hyper-saline waters, with species from the Americas occupying higher intertidal habitats than Indo-west Pacific species mainly found in the low intertidal zone. Here, we characterize numerous osmoregulatory traits in all ten fiddler crabs found along the Atlantic coast of Brazil, and we employ phylogenetic comparative methods using 24 species to test for: (i) similarities of osmoregulatory ability among closely related species; (ii) salinity as a driver of osmoregulatory evolution; (iii) correlation between salt uptake and secretion; and (iv) adaptive peaks in osmoregulatory ability in the high intertidal American lineages. Our findings reveal that osmoregulation in Uca exhibits strong phylogenetic patterns in salt uptake traits. Salinity does not correlate with hyper/hypo-regulatory abilities, but drives hemolymph osmolality at ambient salinities. Osmoregulatory traits have evolved towards three adaptive peaks, revealing a significant contribution of hyper/hypo-regulatory ability in the American clades. Thus, during the evolutionary history of fiddler crabs, salinity has driven some of the osmoregulatory transformations that underpin habitat diversification, although others are apparently constrained phylogenetically. PMID:28182764

  9. Cadmium and naphthalene-induced hyperglycemia in the fiddler crab, Uca pugilator: Differential modes of action on the neutroendocrine system

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, P.S.; Katyayani, R.V.; Fingerman, M. [Tulane Univ., New Orleans, LA (United States)

    1996-03-01

    Hyperglycemia is a typical response of aquatic organisms to heavy metals. In crustaceans, the medulla terminalis X-organ-sinus gland neuroendocrine complex in the eyestalk is the source of the crustacean hyperglycemic hormone (CHH). The role of CHH in pollutant-induced b1ood glucose changes has only recently begun to be studied. Reddy provided evidence that CHH mediates cadmium-induced hyperglycemia in the red swamp crayfish, Procambarus clarkii. In a study of another hormonally-regulated function, color changes, cadmium exposure resulted in pigment in the melanophores of the fiddler crab, Uca pugilator, becoming less dispersed than in unexposed crabs. Earlier studies showed that, like cadmium, both a PCB, Aroclor 1242, and naphthalene induced black pigment aggregation in Uca poor. In general, when crabs are exposed to a pollutant, hydrocarbon or cadmium, they aggregate the pigment in their melanophores, but apparently by different mechanisms. Hydrocarbons appear to inhibit release of black pigment-dispersing hormone (BDPH), whereas cadmium appears to inhibit its synthesis. These apparent different modes of action of cadmium and naphthalene on the color change mechanism led us to compare the impact of these pollutants on the hormonal regulation of blood glucose in Uca pugilator. The present study was performed to determine (1) whether cadmium and naphthalene induce hyperglycemia in Uca pugilator, (2) whether CH has a role, if naphthalene and cadmium do induce hyperglycemia, and (3) the effects, if any, of cadmium and naphthalene on CHH activity in the eyestalk neuroendocrine complex.

  10. Thermal ecology of the fiddler crab Uca panacea: Thermal constraints and organismal responses.

    Science.gov (United States)

    Darnell, M Zachary; Nicholson, Haley S; Munguia, Pablo

    2015-08-01

    Temperature is one of the primary environmental variables limiting organismal performance, fitness, and species distributions. Yet, understanding temperature effects requires thorough exploration of thermal constraints and organismal responses that can translate to fitness and non-lethal long-term consequences under both constant and changing thermal regimes. We examined the thermal ecology of the fiddler crab Uca panacea, including critical thermal limits, thermal sensitivity of locomotion, operative environmental temperatures, preferred body temperatures, and acclimation ability. Operative environmental temperatures frequently reached the critical thermal maximum (41.8±0.8°C, mean ± s.e.m.), especially in unvegetated microhabitats, indicating the need for behavioral thermoregulation to maintain diurnal activity patterns. Preferred body temperatures (21.1-28.6°C) were substantially below the thermal optimum (30-40°C), although further research is needed to determine the driver of this mismatch. Critical thermal limits shifted 2-4°C in response to exposure to low (20°C) or high (35°C) temperatures, with full acclimation occurring in approximately 9d. This capacity for rapid acclimation, combined with the capacity for behavioral thermoregulation, is a strong candidate mechanism that explains the broad habitat use and could help explain the successful pantropical distribution of fiddler crabs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows

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    Takeshita, Fumio; Murai, Minoru

    2016-06-01

    In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.

  12. Ingested microplastics (>100 μm) are translocated to organs of the tropical fiddler crab Uca rapax.

    Science.gov (United States)

    Brennecke, Dennis; Ferreira, Erica C; Costa, Tarso M M; Appel, Daniel; da Gama, Bernardo A P; Lenz, Mark

    2015-07-15

    Microplastics, which are accumulating in marine sediments, are assumed to pose a risk for deposit feeding invertebrates. We tested whether the fiddler crab Uca rapax ingests and retains microplastics in its body. Furthermore, we investigated whether retention rates depend on (a) the quality of the marine environment in which the plastics were pre-weathered and on (b) their abundance. For this, polystyrene pellets were submersed at a polluted and a pristine site near Niterói, Brazil, for 2 weeks. Then specimens of U. rapax were, in laboratory experiments, exposed to fragments (180-250 μm) derived from these pellets for 2 months. After this period, microplastics were observed in the gills, stomach and hepatopancreas of the animals. However, fragment retention was not influenced by the two factors that we manipulated. The presence of microplastics in different organs of the crab supports the assumption that these particles have the potential to harm marine invertebrates.

  13. Fatty acids dynamics during embryonic development in genus Uca (Brachyura: Ocypodidae), from the mangroves of Inhaca Island, Mozambique

    Science.gov (United States)

    Torres, Paulo; Penha-Lopes, Gil; Narciso, Luís; Macia, Adriano; Paula, José

    2008-11-01

    Variations in egg volume and fatty acid (FA) content through embryogenesis were evaluated in Uca species from Inhaca island, Mozambique. Egg volume increased 96.1%, 93.3%, 84.2%, 92.9%, 96.3%, respectively, in Uca annulipes, Uca inversa, Uca urvillei, Uca chlorophthalmus and Uca vocans ( p ecology, nutritional and physiological conditions, differential demands on resource allocation and geographic and seasonal variations in embryonic development.

  14. Population structure of the Atlantic sand fiddler crab Uca pugilator along the eastern coast of US revealed by molecular data

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    David A. WEESE

    2009-04-01

    Full Text Available The Atlantic sand fiddler crab Uca pugilator, is an extremely abundant crab found along the eastern coast of the United States. Fiddler crabs have a life cycle with an obligatory planktonic larval phase of 30–90 days, which might be expected to lead to widespread larval dispersal and consequent genetic homogeneity over considerable distances. However, a large amount of morphological and behavioral variation is found between northern and southern populations along the eastern coast. This study was undertaken to determine the population genetic structure of U.pugilator and to determine whether these differences may have a genetic basis. The population structure of the fiddler crab was analyzed using 472 individuals collected from 12 sites along the eastern coast. PCR-based single stand conformation polymorphism (SSCP was used to investigate between-site variation in the mitochondrial 16S rRNA gene of these individuals. Analysis of genetic variation indicated frequent gene flow between nearby localities, but much reduced levels between populations separated by larger geographic distances. Thus, despite the potential for high dispersal by planktonic larvae, population differentiation and isolation by distance is evident between northern and southern populations of U.pugilator. A high amount of genetic differentiation (FST = 0.3468 was found between northern and southern regions suggesting that the morphological and behavioral differences between these two regions have a genetic basis and may represent subspecies.

  15. Population structure of the Atlantic sand fiddler crab Uca pugilator along the eastern coast of US revealed by molecular data

    Institute of Scientific and Technical Information of China (English)

    David A.WEESE; Denson K.MCLAIN; Ann E.PRATT; Quentin Q.FANG

    2009-01-01

    The Atlantic sand fiddler crab Uca pugilator is an extremely abundant crab found along the eastern coast of the United States. Fiddler crabs have a life cycle with an obligatory planktonic larval phase of 30-90 days, which might be expected to lead to widespread larval dispersal and consequent genetic homogeneity over considerable distances. However, a large amount of morphological and behavioral variation is found between northern and southern populations along the eastern coast. This study was undertaken to determine the population genetic structure of U.pugilator and to determine whether these differences may have a genetic basis. The population structure of the fiddler crab was analyzed using 472 individuals collected from 12 sites along the eastern coast. PCR-based single stand conformation polymorphism (SSCP) was used to investigate between-site variation in the mitochondrial 16S rRNA gene of these individuals. Analysis of genetic variation indicated frequent gene flow between nearby localities, but much reduced levels between populations separated by larger geographic distances. Thus, despite the potential for high dispersal by planktonic larvae, population differentiation and isolation by distance is evident between northern and southern populations of U.pugilator. A high amount of genetic differentiation (FST=0.3468) was found between northern and southern regions suggesting that the morphological and behavioral differences between these two regions have a genetic basis and may represent subspecies [Current Zoology 55(2):150-157,2009].

  16. Crescimento relativo em Uca leptodactyla Rathbun (Crustacea Decapoda Ocypodidae Relative growth in the fiddler crab Uca leptodactyla Rathbun (Crustacea Decapoda Ocypodidae

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    Setuko Masunari

    2003-09-01

    Full Text Available Relative growth of the male major chela and female abdome was studied in a population of the fiddler crab Uca leptodactyla Rathbun, 1898 from Itapoá, Santa Catarina coast, southern Brazil. Major chela length (CMQ was measured from 191 males, and abdomen width (LAB from 128 females. Carapace width (LC was the reference dimension for both sexes, which ranged from 3.9 to 11.5 mm for males, and from 3.15 to 10.65 mm for females. Males grew bigger than females. Relationship between CMQ and LC showed a transition point at 8.35 mm LC in males, and between LA and LC at 7.10 mm LC in females. Growth was allometrically positive in the early ontogenesis and isometric after the puberal molting for both sexes. Regressions between LC and CMQ in males read as: logCMQ = -0,854536 + 2,19. logLC for empirical points at left of critical point and logCMQ = 0,063047 + 1,24. logLC for those at right. In females, this relation was logLAB = -0,603590 + 1,30. logLC and logLAB = -0,361464 + 1,07. logLC, respectively. These body dimensions were connected with reproductive activity of this species.

  17. Contrasting Effects of Two Burrowing Crabs ( Chasmagnathus granulata and Uca uruguayensis) on Sediment Composition and Transport in Estuarine Environments

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    Botto, F.; Iribarne, O.

    2000-08-01

    The burrowing crabs Chasmagnathus granulata and Uca uruguayensis are important bioturbators of intertidal flats in SW Atlantic estuaries reworking large amounts of sediment ( C. granulata 2234·6 g m -2day -1, U. uruguayenis 678·9 g m -2day -1) and influencing sediment quality and bedload transport. Their activities increase substrate penetrability. Organic matter and water content are higher in crab beds when compared with nearby areas without crabs. Burrows of U. uruguayensis are closed during high tide while burrows of C. granulata are always open effectively trapping clay and silt size particles rich in organic matter. This trapping of sediment enhances the effect of C. granulata in modifying sediment characteristics. Both species impact sediment erodability but have contrasting effects on sediment bedload transport. Daily bedload transport was lower inside C. granulata beds than outside, while it was higher in U. uruguayensis beds when compared with control areas. While C. granulata stabilizes the sediment by placing fine and cohesive sediment on the surface, U. uruguayensis disrupts the sediment by pelletizing it and making it more easily eroded. The contrasting activities of these two species may produce opposing and significant impacts on the structure of the benthic community because of their impact on sediment stability.

  18. Behavioural, ecological and physiological plasticity of East African fiddler crab (genus Uca): a paradigm of terrestriality

    OpenAIRE

    Carmelo La Barba

    2015-01-01

    Studio comparativo su fisiologia respiratoria, terrestrialità e territorialità dei granchi fiolinisti in ambiente di magrovia. A comparative study on respiratory physiology, terrestriality and territoriality of fiddler crabs in mangrove ecosystem

  19. Epidermal collagenase activity and its induction by 20-hydroxyecdysone in the fiddler crab Uca pugilator

    Institute of Scientific and Technical Information of China (English)

    Erin A.TOUPS; Enmin ZOU

    2009-01-01

    The epidermal collagenase activity and its induction by 20-hydroxyecdysone in Uca pugilator were investigated.Zymographic electrophoresis showed four bands of collagenae activity,16,19,22 and 29 kDa in molecular weight,with the former two accounting for 60% and 36%,respectively,of the total coUagenase activity. The collagenase activity varies during the molting cycle. Among the molt stages tested,Premoh Stage Do exhibited the highest epidermal coUagenase activity for both the 16 and 19 kDa isoenzymes and,as the molt stage proceeded,the enzymatic activity of these two isoenzymes decreased,with the lowest activity for both found in Premoh Stage D3-4. Injection of 20-hydroxyecdysone significantly induced the activity of the 16 kDa collagenase in the epidermis of Uca pugilator,suggesting that the activity of this isoenzyme is under molting hormone control.Although 20-hydroxyecdysone injection did not result in a statistically significant increase in the activity of the 19 kDa isocnzyme,a tendency of the induction was nonetheless demonstrated. This is the first report on epidermal collagenase activity and its induction by the molting hormone in a crustacean.

  20. Flocking and feeding in the fiddler crab (UCA tangeri) : Prey availability as risk-taking behaviour

    NARCIS (Netherlands)

    Ens, B; KLAASSEN, M; ZWARTS, L

    1993-01-01

    For a full understanding of prey availability, it is necessary to study risk-taking behaviour of the prey. Fiddler crabs are ideally suited for such a study, as they have to leave their safe burrow to feed on the surface of the intertidal flats during low tide, thereby exposing themselves to avian

  1. Distribuição e abundância dos caranguejos Uca Leach (Crustacea, Decapoda, Ocypodidae na Baía de Guaratuba, Paraná, Brasil Distribution and abundance of fiddler crabs Uca Leach (Crustacea Decapoda Ocypodidae in Guaratuba Bay, Parana State, southern Brazil

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    Setuko Masunari

    2006-12-01

    Full Text Available Um estudo sobre distribuição espacial e abundância dos chama-marés Uca Leach, 1814 foi realizado na Baía de Guaratuba, Estado do Paraná. Foram coletados chama-marés de dez biótopos ao longo de um gradiente de salinidade de zero a 32 dentro da Baía de Guaratuba. Foram obtidas sete espécies, entre as quais, Uca mordax (Smith, 1870 que foi registrada somente em biótopos inundados por águas de baixas salinidades (de zero a 16. As demais espécies mostraram tolerância a uma ampla variação de salinidade, mas Uca maracoani (Latreille, 1802-1803 e Uca leptodactyla Rathbun, 1898 predominaram em águas mais salinas, de 14 a 32, enquanto U. burgersi Holthuis, 1967, Uca rapax (Smith, 1870, Uca thayeri Rathbun, 1900 e Uca uruguayensis Nobili, 1901 foram coletadas em mais de três biótopos e mostraram uma tendência ao eurihalismo, suportando salinidades de 4 a 32. Entretanto, outras características do substrato tais como porcentagem relativa de cascalho/areia/silte/argila, teor de matéria orgânica e presença de marismas, também, influenciaram a distribuição espacial destes caranguejos. U. leptodactyla foi registrada com densidade máxima de 240 ind.m-2, o mais alto valor conhecido.A study of the spatial distribution and abundance of fiddler crabs was carried out in Guaratuba Bay, Parana State, southern Brazil. Fiddler crabs were collected from 10 biotopes located along a salinity gradient from zero to 32 inside Guaratuba Bay (between 48°30'W-25°50'S and 48°45'W-25°54'S. Seven species were found, among which, Uca mordax (Smith, 1870 occurred only in biotopes inundated by low salinity water, from zero to 16. Remaining species tolerated wide range of salinity oscillation, but Uca maracoani (Latreille, 1802-1803 and Uca leptodactyla Rathbun, 1898 predominated in saltier waters, from 14 to 32, while U. burgersi Holthuis, 1967, Uca rapax (Smith, 1870, Uca thayeri Rathbun, 1900, and Uca uruguayensis Nobili, 1901 were collected in more

  2. Determination of key environmental factors responsible for distribution patterns of fiddler crabs in a tropical mangrove ecosystem.

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    Mohammad Mokhtari

    Full Text Available In tropical regions, different species of fiddler crabs coexist on the mangrove floor, which sometimes makes it difficult to define species-specific habitat by visual inspection. The aim of this study is to find key environmental parameters which affect the distribution of fiddler crabs and to determine the habitats in which each species was most abundant. Crabs were collected from 19 sites within the mudflats of Sepang-Lukut mangrove forest. Temperature, porewater salinity, organic matter, water content, carbon and nitrogen content, porosity, chlorophyll content, pH, redox potential, sediment texture and heavy metals were determined in each 1 m2 quadrate. Pearson correlation indicated that all sediment properties except pH and redox potential were correlated with sediment grain size. Canonical correspondence analysis (CCA indicated that Uca paradussumieri was negatively correlated with salinity and redox potential. Sand dwelling species, Uca perplexa and Uca annulipes, were highly dependent on the abundance of 250 μm and 150 μm grain size particles in the sediment. Canonical Discriminative Analysis (CDA indicated that variation in sediment grain size best explained where each crab species was most abundant. Moreover, U. paradussumieri commonly occupies muddy substrates of low shore, while U. forcipata lives under the shade of mangrove trees. U. annulipes and U. perplexa with the high number of spoon tipped setae on their second maxiliped are specialized to feed on the sandy sediments. U. rosea and U. triangularis are more common on muddy sediment with high sediment density. In conclusion, sediment grain size that influences most sediment properties acts as a main factor responsible for sediment heterogeneity. In this paper, the correlation between fiddler crab species and environmental parameters, as well as the interaction between sediment characteristics, was explained in order to define the important environmental factors in fiddler crab

  3. Determination of key environmental factors responsible for distribution patterns of fiddler crabs in a tropical mangrove ecosystem.

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    Mokhtari, Mohammad; Ghaffar, Mazlan Abd; Usup, Gires; Cob, Zaidi Che

    2015-01-01

    In tropical regions, different species of fiddler crabs coexist on the mangrove floor, which sometimes makes it difficult to define species-specific habitat by visual inspection. The aim of this study is to find key environmental parameters which affect the distribution of fiddler crabs and to determine the habitats in which each species was most abundant. Crabs were collected from 19 sites within the mudflats of Sepang-Lukut mangrove forest. Temperature, porewater salinity, organic matter, water content, carbon and nitrogen content, porosity, chlorophyll content, pH, redox potential, sediment texture and heavy metals were determined in each 1 m2 quadrate. Pearson correlation indicated that all sediment properties except pH and redox potential were correlated with sediment grain size. Canonical correspondence analysis (CCA) indicated that Uca paradussumieri was negatively correlated with salinity and redox potential. Sand dwelling species, Uca perplexa and Uca annulipes, were highly dependent on the abundance of 250 μm and 150 μm grain size particles in the sediment. Canonical Discriminative Analysis (CDA) indicated that variation in sediment grain size best explained where each crab species was most abundant. Moreover, U. paradussumieri commonly occupies muddy substrates of low shore, while U. forcipata lives under the shade of mangrove trees. U. annulipes and U. perplexa with the high number of spoon tipped setae on their second maxiliped are specialized to feed on the sandy sediments. U. rosea and U. triangularis are more common on muddy sediment with high sediment density. In conclusion, sediment grain size that influences most sediment properties acts as a main factor responsible for sediment heterogeneity. In this paper, the correlation between fiddler crab species and environmental parameters, as well as the interaction between sediment characteristics, was explained in order to define the important environmental factors in fiddler crab distributions.

  4. Distribution and characteristic of deposit-feeder crabs (Crustacea: Brachyura in some mangrove ecosystem types in Lombok Island

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    Dewi Citra Murniati

    2016-02-01

    Full Text Available Lombok Island consists of five different mangrove forest types with various pattern of fauna distribution. These pattern variations were constructed by different type of substrates. Deposit feeder crabs play an important role in determination of substrate pattern. The objective of this study was to investigate the distribution pattern of some crabs which their characteristics are correlated to the mangroves substrate. Crabs were collected from eight locations in Mangrove area of Lombok Island. Ten species of the deposit feeder crab were identified, their distribution pattern was illustrated based on the result of field observation on their morphological characteristics. The highest species diversity found in Teluk Rasu and Tanjung Luar. Both cheliped and maxilliped characteristics represent to habitat preference. Uca annulipes, U. perplexa, U. vocans, and Dotilla myctiroides inhabited sandy substrate, while U. bellator, U. demani, U. dussumieri, U. forcipata, U. triangularis, and Tmethypocoelis ceratophora inhabit muddy substrate.

  5. Relative growth in the fiddler crab Uca uruguayensis Nobili, 1901 (Brachyura, Ocypodidae from Garças River mangrove, Guaratuba Bay, southern Brazil

    Directory of Open Access Journals (Sweden)

    Salise Brandt Martins

    Full Text Available A study on the relative growth was carried out in a population of the fiddler crab Uca uruguayensis from the mangrove of Garças River, Guaratuba Bay, Paraná State, southern Brazil. The dimensions analyzed were the length of the major chela (LMC of males and width of the abdomen (AW of females, because they are related to reproductive activities of waving (males and egg incubation (females. The cheliped handedness in males was also analyzed. The LMC was measured in 480 males, the AW in 566 females, and all crabs had the carapace width (CW measured that was considered as the reference dimension for both sexes. The inflection point in the graphs between each the dimensions and CW was calculated with the aid of the software REGRANS. The CW ranged from 2.33 to 8.33 mm in males and from 1.65 to 7.79 mm in females. The relationship between CW and LMC showed an inflection point at 4.14 mm CW among males, and between CW and AW at 3.52 mm CW among females. The allometric growth was positive for both dimensions throughout the entire ontogeny of both sexes, before and after the puberty. The equations describing the relationship between CW and LMC in males were: logLMC = - 0.695960 + 1.72.logCW for juveniles and logLMC = - 1.212513 + 2.5.logCW for adults. In females, the equations were logAW = - 0.519071 + 1.02.logCW and logAW = - 0.902874 + 1.73.logCW, respectively for juveniles and adults. The population of U. uruguayensis from Guaratuba Bay is composed of the smallest crabs, and it also attains morphological sexual maturity at smallest CW. The frequency of occurrence of right and left handed males was statistically the same (1:1 as in most population of fiddler crabs.

  6. Good Crab, Bad Crab

    Science.gov (United States)

    Are crabs friends or foes of marsh grass, benefit or detriment to the salt marsh system? We examined Uca pugilator (sand fiddler) and Sesarma reticulatum (purple marsh crab) with Spartina patens (salt marsh hay) at two elevations (10 cm below MHW and 10 cm above MHW) in mesocosms...

  7. FLOCKING AND FEEDING IN THE FIDDLER-CRAB (UCA-TANGERI) - PREY AVAILABILITY AS RISK-TAKING BEHAVIOR

    NARCIS (Netherlands)

    ENS, BJ; KLAASSEN, M; ZWARTS, L

    1993-01-01

    For a full understanding of prey availability, it is necessary to study risk-taking behaviour of the prey. Fiddler crabs are ideally suited for such a study, as they have to leave their safe burrow to feed on the surface of the intertidal flats during low tide, thereby exposing themselves to avian p

  8. Comparison of the population structure of the fiddler crab Uca vocator (Herbst, 1804 from three subtropical mangrove forests

    Directory of Open Access Journals (Sweden)

    Karine Delevati Colpo

    2004-03-01

    Full Text Available The population structure of U. vocator was investigated during a one-year period in three mangrove forests in southeast Brazil. The study specifically addressed comparisons on individual size , juvenile recruitment and sex-ratio. The structure of the mangrove forests, i.e. density, basal area, and diameter, and the physical properties of sediments, i.e. texture and organic matter contents, were also examined. A catch-per-unit-effort (CPUE technique was used to sample the crab populations using 15-min sampling periods by two people. Males always outnumbered females, probably due to ecological and behavioural attributes of these crabs. The median size of fiddler crabs differed among the sampled populations. The mangroves at Indaiá and Itamambuca showed higher productivity than those at Itapanhaú, where oil spills impacting the shore were reported. Marked differences were found regarding individual size , either their size at the onset of sexual maturity or their asymptotic size, suggesting that food availability may be favouring growth in the studied populations.

  9. Molt and reproduction enhancement together with hemolymph ecdysteroid elevation under eyestalk ablation in the female fiddler crab, Uca triangularis (Brachyura: Decapoda)

    Science.gov (United States)

    Supriya, Nagathinkal T.; Sudha, Kappalli; Krishnakumar, Velayudhannair; Anilkumar, Gopinathan

    2016-07-01

    We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanisms of these two highly energy-demanding processes. Bilateral eyestalk ablation resulted in precocious acceleration of both molting and reproduction, irrespective of the season at which each experiment was conducted. The rate of accelerated ovarian growth, however, was maximum if the eyestalk ablation was conducted during August-January, the breeding season in the wild, or in February-May (molting-reproductive season), wherein a section of the wild population would be engaged in molting and another section in breeding. The highest degree of precocious molt acceleration, on the other hand, was obtained during June-July when the population was primarily engaged in molting, but with no reproductive activity. The precocious oocyte maturation (due to de-eyestalking) was minimal in June-July. Significantly, the eyestalk ablation also resulted in a dramatic increase in the hemolymph ecdysteroid titer, revealing that a high ecdysteroid titer would have no restraining influence on vitellogenesis. No spawning was, however, observed among de-eyestalked females, even though their final oocyte size surpassed the size of the normal mature oocytes, implying that spawning is not exclusively under the control of eyestalk hormones. A comparative study performed on the vitelline components of the experimentals and the controls revealed that the precociously incorporated yolk under eyestalk ablation was biochemically impoverished. These results indicate that throughout the annual cycle, both the somatic and the reproductive growth of U. triangularis are under the influence of inhibitory principles from the eyestalks. It is also revealing that mere deprival of the inhibitory principles does not culminate into successful vitellogenesis. Arguably, the inhibitory influence from

  10. The nomenclatural status of the two "spiny-wristed" fiddler crabs: Uca spinicarpa Rathbun, 1900, and U. hesperiae Crane, 1975 (Crustacea: Brachyura: Ocypodidae).

    Science.gov (United States)

    Rosenberg, Michael S

    2013-01-01

    A secondary homonymy is documented for Gelasimus [= Uca] tetragonon var. spinicarpa Kossmann, 1877 (a species from the Red Sea), and Uca spinicarpa Rathbun, 1900 (a species from the Gulf of Mexico). Although Kossmann's usage of the nomen spinicarpa has chronological priority, a reversal of precedence is required by Article 23.9 of the Code since Kossmann's use has not been applied as a valid name since the original publication in 1877, while Rathbun's use of the name has been applied over 50 times in the last half century. The species Kossmann was most likely referring to is today known as Uca hesperiae Crane, 1975, a name which may be retained in light of the reversal of precedence.

  11. Effects and mechanism of action of naphthalene, a petroleum-derived polycyclic aromatic hydrocarbon, on black pigment dispersion in the salt marsh fiddler crab, UCA pugilator

    Energy Technology Data Exchange (ETDEWEB)

    Staub, G.C.

    1983-01-01

    At a concentration of approximately 8 ppm, naphthalene inhibited circadian black pigment dispersion in the integumentary chromatophores of the fiddler crab no matter what the initial state of the black pigment. The inhibition was concentration dependent. Naphthalene was not toxic to fiddler crabs under these conditions at any concentration up to 16.69 ppm. No chemically induced phase shift in the circadian rhythm of naphthalene exposed crabs occurs. In addition there is no difference in the mean black chromatophore index at midnight between control and naphthalene exposed crabs, indicating that the release of black pigment concentrating hormone (BPCH) is not being influenced by naphthalene. The only possibility remaining is that naphthalene must interfere with some aspect of the control of BPDH release by NE. Exposure to naphthalene does not inhibit black pigment dispersion when crabs are placed on a black background or kept on a black background throughout the experiment. This argues against naphthalene acting to inhibit the synthesis of NE, or to promote its metabolism, since NE is involved in adaptation to a black background. Naphthalene, therefore, must act to prevent the release of BPDH by interfering with some aspect of the presynaptic control of BPDH release by NE.

  12. Ciclo reprodutivo do caranguejo violinista Uca rapax (Smith (Crustacea, Brachyura, Ocypodidae habitante de um estuário degradado em Paraty, Rio de Janeiro, Brasil Reproductive cicle of the fiddler crab Uca rapax (Smith (Crustacea, Brachyura, Ocypodidae at a degraded estuary in Paraty, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Daniela da S. Castiglioni

    2006-06-01

    Full Text Available Este trabalho descreve o ciclo reprodutivo de Uca rapax (Smith, 1870 baseado em observações do seu desenvolvimento gonadal e ciclo de muda em uma área de manguezal degradado em Paraty, Estado do Rio de Janeiro. Os caranguejos foram capturados por duas pessoas mensalmente (julho/2001 a junho/2002 durante 15 minutos por meio da técnica de esforço de captura em período de maré baixa. No laboratório, os caranguejos foram mensurados quanto à largura da carapaça (LC; sendo o sexo, a condição ovígera e o estágio gonadal anotados. Os estágios de desenvolvimento gonadal foram determinados por meio da observação macroscópica das gônadas e os estágios de muda através da observação do grau de enrijecimento do tegumento. Os caranguejos que apresentavam gônadas imaturas e rudimentares foram considerados imaturos enquanto os demais estágios gonadais, maduros. Obteve-se um total de 1558 espécimes, sendo 801 machos e 757 fêmeas (16 fêmeas ovígeras. As fêmeas ovígeras representaram apenas 3% da população, talvez pelo fato destas fêmeas permanecerem em suas tocas. Apesar de terem sido encontrados caranguejos com gônadas maduras ao longo de todo o ano, o período de maior atividade reprodutiva em U. rapax ocorre nos meses mais quentes do ano (primavera-verão. A freqüência de caranguejos em atividade de muda ao longo do período de estudo foi baixa (12,8% em relação aos caranguejos em intermuda. Provavelmente, U. rapax permaneça entocada nesse período crítico, que é a troca do exoesqueleto. Apesar de U.rapax ocorrer em um manguezal completamente degradado, o seu ciclo reprodutivo não foi afetado, quando comparado com de áreas não degradadas estudadas anteriormente. Tal fato pode ser sustentado pela presença de caranguejos potencialmente maduros ao longo do ano todo na área de estudo.This present work describes the reproductive cycle of Uca rapax (Smith, 1870 based on observations of their gonadal development and molt

  13. Contribuição ao conhecimento dos crustaceos do Rio de Janeiro: Genero Uca (Decapoda: Ocypodidae

    Directory of Open Access Journals (Sweden)

    Lejeune P. H. de Oliveira

    1939-01-01

    Full Text Available This paper comprises: 1 A note on Systematists of fiddler crabs from the Bay of Rio de Janeiro, with its new species Uca olympioi, Uca salsisitus, and a new variety U. pugnax var. brasiliensis. 2 Female Uca characterization is easier and infuse certainness when we inquire her third maxillipod. 3 Redescriptions are made for type-locality animals at Rio de Janeiro and nearness. 4 Male characterization become possible through its maxillipod if we lose its quelipod. 5 A historical referendary originating into indigenous dialect « Guarany » about the name Uca and brasilian nicknames of the fiddler crabs. 6 A few Uca species from the Rio de Janeiro determinative keys asked after main distinctions among others species described over the world in paragraph « diagnose diferencial ». 7 A collected material catalogue and some mensurement tables.

  14. ASPECTOS BIOLÓGICOS DE Euborellia annulipes (DERMAPTERA: ANISOLABIDIDAE ALIMENTADA COM O PULGÃO Hyadaphis foeniculi (HEMIPTERA: APHIDIDAE

    Directory of Open Access Journals (Sweden)

    ALDENI BARBOSA DA SILVA

    2010-01-01

    Full Text Available The cultivation of sweet herb of great economic importance for small farmers in the micro and Agrest Swamp of Paraíba and also in the state of Pernambuco. Among the natural enemies, the scissors Euborellia annulipes proves to be a voracious predator, that is, with high ability to attack and feed on different prey, particularly of eggs and immature stages of insects of Lepidoptera, Hemiptera, Coleoptera and Diptera. The objective of this research was to study the biological aspects of E. annulipes on H. foeniculi laboratory. The study was conducted at the Entomology Laboratory, Department of Plant Protection at the UFPB in a climatic chamber, at 25 ± 1 ºC, relative humidity of 70 ± 10% RH and 12 hours. Scissors were selected in adulthood from rearing on artificial diet in the laboratory. From these insects have made observations of posture, viability and morphology of eggs of E. annulipes. Fifty nymphs were selected for each stage of development (1, 2, 3, 4 and 5 of the scissors and fed separately with aphids (1st-2nd, 3rd and 4th instar. There has been evaluation regarding the number and duration of instars. There are five instars to the nymphal stage of E. annulipes, the average incubation period was 12.9 days, pre-oviposition period of 18.2 days and 46.75 eggs per clutch, there was an increase of nymphal E. annulipes in that it offered up more aphids developed.

  15. Capacidade Predatória de Euborellia annulipes (Lucas, 1847 sobre Spodoptera frugiperda (Smith, 1797 = Predatory Capacity of Euborellia annulipes (Lucas, 1847 on Spodoptera frugiperda (Smith, 1797

    Directory of Open Access Journals (Sweden)

    Aldeni Barbosa da Silva

    2009-01-01

    Full Text Available Estudou-se a Capacidade Predatória de Euborellia annulipes sobre Spodoptera frugiperda em laboratório. O estudo foi conduzido no Laboratório de Entomologia do Setor de Fitossanidade da Universidade Federal da Paraíba (UFPB à temperatura de 25 ± 1ºC, umidade relativa de 70 + 10% e fotofase de 12h. Notou-se consumo crescente de ovos,podendo ser observado consumo diário médio de 11,06, 49,02, 122,7, 148,09 e 374,9 ovos, do 1° ao 5° instar, respectivamente. A capacidade predatória sobre lagartas de 1° instar de S. frugiperda aumentou de acordo com o seu desenvolvimento, com aumento de,aproximadamente, 14,3 vezes do 1° ao 5° instar, nos dez dias de consumo, sendo que, o 4° e o 5° instares apresentaram consumo diário médio de 25,5 e 26,6, respectivamente, bem superior em comparação aos demais instares; o maior consumo de lagartas de 2º instar pelopredador, ocorreu no 4º e 5º instar, que apresentaram consumo diário médio de 12,8 e 15,1, respectivamente. Verifica-se que E. annulipes demonstra ser predador potencial de ovos e lagartas de S. frugiperda, chegando um adulto a consumir 1.481,2; 89,20 e 48,6 ovos e lagartasde 1º e 2º instares, respectivamente, nos dez dias de consumo.The predatory capacity of Euborellia annulipes on Spodopterafrugiperda was studied in a laboratory setting. The study was conducted in the Laboratory of Entomology of the Division of Plant Protection, Federal University of Paraíba (UFPB at a temperature of 25 ± 1°C, relative humidity of 70 + 10% and a 12-hour photophase. Thestudy detected growing egg intake, with an average daily consumption of 11.06, 49.02, 122.7, 148.09 and 374.9 eggs, from the first to the fifth instars, respectively. A predatory capacity of fist-instar larvae of S. frugiperda increased in line with its development, with an increase of approximately 14.3 times from the first to the fifth instar, in the 10 days of consumption, whereas the fourth and fifth instars presented an

  16. The effect of salinity on larval development of Uca tangeri (Eydoux, 1835 (Brachyura: Ocypodidae and new findings of the zoeal morphology

    Directory of Open Access Journals (Sweden)

    Eduardo D. Spivak

    2009-06-01

    Full Text Available In order to evaluate their tolerance to low salinities, zoeae of the fiddler crab Uca tangeri from the Rio San Pedro population (southwestern Spain were reared in the laboratory at 20ºC and at three salinities (16, 24 and 32. The zoeal development was completed at 24 and 32 but the crabs died as zoea I or zoea II, and very rarely as zoea III, at 16; tolerance to low salinities varied among clutches produced by different females. The duration of the first zoeal stage and of the complete zoeal development was shorter at 32. Our observations showed that the zoeae of U. tangeri could not tolerate retention in the mesohaline water of estuaries, and that export to oceanic waters would be optimal for their successful development. Survival at 24 suggests that larvae could also develop in polyhaline conditions if they were retained in the ocean-estuary interface. The presence of an additional zoeal stage (zoea VI was observed in some individuals and associated with unfavourable combinations of temperature and salinity. In addition, some previously omitted aspects of zoeal morphology were re-described and illustrated, providing new evidence which supports the basal position of this species in a proto-Atlantic origin of the genus Uca. It is proposed that the differences between Uca tangeri and the rest of the Uca species should be highlighted, and that it should be placed in its own genus as Afruca tangeri.

  17. Effects of simulated oil exposure on two intertidal macrozoo benthos: Tympanotonus fuscata (L.) and Uca tangeri (Eydoux, 1935) in a tropical estuarine ecosystem.

    Science.gov (United States)

    Ewa-Oboho, I O; Abby-Kalio, N J

    1994-08-01

    The impacts of simulated Nigerian light crude oil on mud flat periwinkles, Tympanotonus fuscata (L.), and fiddler crabs, Uca tangeri (Eydoux, 1935) was examined through field experiments conducted in the Bonny estuary of the Niger Delta (southern Nigeria). The purpose was to assess the fate and effects of a known quantity of the Nigerian light crude oil on this environment. Drastic changes in the densities of T. fuscata and U. tangeri observed immediately after spills was attributed to the effects of the oil. A large increase in Uca biomass occurred in the affected area. Salinity and temperature in the study area showed little fluctuations throughout the survey. Sediment characteristics were similar for all sites (stations). Grain-size analysis revealed that sediments at the study area were 70% silt. Migration of oil via tidal percolation was observed as much as 11 cm beneath the sediment surface.

  18. Contenido bioquímico del ovario y hepatopáncreas de Uca longisignalis y Uca nr. minax

    OpenAIRE

    Hasek, Barbara E.; Felder, Darryl L.

    2006-01-01

    Se analizó la composición bioquímica de tejidos del ovario y hepatopáncreas de poblaciones naturales de Uca longisignalis and Uca nr. minax durante la época reproductiva. Se cuantificaron lípidos totales (concentración y contenido), C (carbono), N (nitrógeno), y los cocientes C:N del ovario y hepatopáncreas durante el proceso de maduración del ovario. Los lípidos y la concentración de C variaron significativamente durante el curso de maduración del ovario en ambas especies, pero no se ...

  19. Verwandtschaftliche Gruppierung und Verbreitung der Karibischen Winkerkrabben (Ocypodidae, Gattung Uca)

    NARCIS (Netherlands)

    Hagen, H.O.V.

    1970-01-01

    EINLEITUNG Bei einem Aufenthalt auf der westindischen Insel Trinidad in den Jahren 1965/66 hatte ich Gelegenheit, die meisten karibischen Winkerkrabben der Gattung Uca sowie Daten über ihre Biologie, Ökologie und Verbreitung zu sammeln. Ein Teil des Materials, d.h. Vertreter aller 9 auf Trinidad

  20. Variation of Sediment Properties among the Radial Profiles of Fiddler Crab Burrows in Mangrove Ecosystem

    Directory of Open Access Journals (Sweden)

    Mohammad Mokhtari

    2016-01-01

    Full Text Available Fiddler crabs burrow creates oxic-anoxic interfaces on the burrow walls. Accordingly burrow walls represent the transitions site between oxic and anoxic condition where the sediment properties varied significantly across it. In this study the burrows of three species of fiddler crabs including Uca rosea, Uca forcipata and Uca pardussumieri were sampled at three depth layers. Sediment properties of burrow walls including; temperature, redox potential, pH, density, porosity, water content, organic content, chlorophyll content and solid phase iron pools were measured to determine the magnitude of burrow effects on mangrove sediments. The results indicated that U. paradussumieri effectively reduced the sediment porosity of surrounding sediments down to 45%. Oxidized layer was more extended around U. paradussumieri burrows. Burrow walls of U. forcipata and U. paradussumieri contain higher water content than ambient sediment and burrows of U. rosea efficiently decreased the organic content of sediment. The PCA biplots indicated that the burrow walls of the all three species of fiddler crabs at 3 and 8 cm depth were correlated with oxidized iron. Ambient sediments of U. forcipata habitat were correlated with reduced iron and organic content. At 20 cm depth, burrow walls of U. paradussumieri were highly correlated with water content, while ambient sediment was correlated with reduced iron. The results of this study revealed that the thickness of oxidized layer varied according to sediment depth and burrow volume. Consequently the burrow effect varied significantly among different species of fiddler crabs as results of different habitat characteristics, sediment types and crab size.

  1. Estructura del aparato reproductor masculino de Uca uruguayensis (Decapoda, Ocypodidae)

    OpenAIRE

    Cuartas,Elena Irene; Petriella,Ana María

    2010-01-01

    The structure of the male reproductive tract was described in Uca uruguayensis Nobili, 1901, by using histological methods, scanning electron microscopy techniques, and stereoscopic observations of fresh material. The aim of this work was to establish the functional changes associated with sexual maturation. The morphology of the first (G1) and second (G2) pair of gonopods was described. The male reproductive tract consists of paired organs: testes, and tubular and convoluted vas deferens (VD...

  2. Gut-Associated Microbial Symbionts of the Marsh Fiddler Crab, Uca Pugnax

    Science.gov (United States)

    2004-09-01

    and readily digested starches (Stevens and Hume 1995), have sufficient endogenous enzymes to process their diets and therefore have been predicted to... polyacrylamide , 30-60% or 20-70% denaturant). Gels of 20-70% denaturant were used initially to assess the complete spectrum of 80 diversity patterns. A narrower...strict anaerobes involved in starch degradation (Mccarthy et al. 1988). Furthermore, Sebaldella termitidis, previously Bacteroides termitidis, produces

  3. Circulating Long Noncoding RNA UCA1 as a Novel Biomarker of Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Youyou Yan

    2016-01-01

    Full Text Available Acute myocardial infarction (AMI is the most serious cardiovascular disease with high morbidity and mortality. Recent studies have showed that long noncoding RNAs (lnc RNA play important roles in pathophysiology of cardiovascular diseases, but the investigations are still in their infancy. An lnc RNA named urothelial carcinoma-associated 1 (UCA1 is found in tumors such as bladder cancers and lung cancer. And the UCA1 could be as a predictive biomarker for bladder cancer in urine samples or lung cancer in plasma, respectively. In normal states, UCA1 is specifically expressed in heart of adult, indicating that UCA1 might be as a biomarker for heart diseases such as AMI. To test the speculation, we detect the level of UCA1 in plasma of AMI patients and health control using quantitative reverse transcription-polymerase chain reaction (qRT-PCR. In addition, we also test the level of miR-1 as it is reported to regulate the expression of UCA1. The results show that the level of plasma UCA1 is decreased at the early state of AMI patients and increased at day 3 after AMI. In addition, the UCA1 alteration is inversely associated with the expression of miR-1. These findings indicate that the circulating UCA1 could be used as a promising novel biomarker for the diagnosis and/or prognosis of AMI.

  4. Relating disparity in competitive foraging behavior between two populations of fiddler crabs to the subcellular partitioning of metals.

    Science.gov (United States)

    Khoury, Jacques N; Powers, Evelyn; Patnaik, Pradyot; Wallace, William G

    2009-04-01

    Behavioral changes in aquatic organisms such as reduced prey capture and decreased mobility have been linked to exposure to contaminants in the field. The purpose of this study was to compare competitive foraging and dominance behaviors of two populations of the fiddler crab, Uca pugnax, and to examine the relationship between tissue metal residues and observed differences in behavior. Foraging behavior (number of total scoops and scoops on a protein-rich patch) and dominance behavior (percentage of successful attacks) of fiddler crabs from an impacted site (Meredith Creek, New York) and a reference site (Tuckerton, New Jersey) were compared in the laboratory. Tuckerton (Tk) crabs were found to have twice the number of total scoops (70 vs. 38 scoops, p competitive foraging behavior in fiddler crabs. Additionally, this study shows that when compared with dominance behavior, foraging behavior is a more sensitive indicator of metal exposure and might be used as an end point in ecotoxicology studies.

  5. Crab Rationalization Permit Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Crab Rationalization Program (Program) allocates BSAI crab resources among harvesters, processors, and coastal communities. The North Pacific Fishery Management...

  6. Crab Cavity Development

    CERN Document Server

    Calaga, R; Burt, G; Ratti, A

    2015-01-01

    The HL-LHC upgrade will use deflecting (or crab) cavities to compensate for geometric luminosity loss at low β* and non-zero crossing angle. A local scheme with crab cavity pairs across the IPs is used employing compact crab cavities at 400 MHz. Design of the cavities, the cryomodules and the RF system is well advanced. The LHC crab cavities will be validated initially with proton beam in the SPS.

  7. Estructura del aparato reproductor masculino de Uca uruguayensis (Decapoda, Ocypodidae) Structure of the male reproductive tract of Uca uruguayensis (Decapoda, Ocypodidae)

    National Research Council Canada - National Science Library

    Elena Irene Cuartas; Ana María Petriella

    El objetivo de este trabajo es describir las estructuras del sistema reproductor de machos de Uca uruguayensis Nobili, 1901 y estudiar los cambios relacionados con la madurez sexual. Se trabajó con observación...

  8. The prognostic significance of UCA1 for predicting clinical outcome in patients with digestive system malignancies.

    Science.gov (United States)

    Liu, Fang-Teng; Dong, Qing; Gao, Hui; Zhu, Zheng-Ming

    2017-06-20

    Urothelial Carcinoma Associated 1 (UCA1) was an originally identified lncRNA in bladder cancer. Previous studies have reported that UCA1 played a significant role in various types of cancer. This study aimed to clarify the prognostic value of UCA1 in digestive system cancers. The meta-analysis of 15 studies were included, comprising 1441 patients with digestive system cancers. The pooled results of 14 studies indicated that high expression of UCA1 was significantly associated with poorer OS in patients with digestive system cancers (HR: 1.89, 95 % CI: 1.52-2.26). In addition, UCA1 could be as an independent prognostic factor for predicting OS of patients (HR: 1.85, 95 % CI: 1.45-2.25). The pooled results of 3 studies indicated a significant association between UCA1 and DFS in patients with digestive system cancers (HR = 2.50; 95 % CI = 1.30-3.69). Statistical significance was also observed in subgroup meta-analysis. Furthermore, the clinicopathological values of UCA1 were discussed in esophageal cancer, colorectal cancer and pancreatic cancer. A comprehensive retrieval was performed to search studies evaluating the prognostic value of UCA1 in digestive system cancers. Many databases were involved, including PubMed, Web of Science, Embase and Chinese National Knowledge Infrastructure and Wanfang database. Quantitative meta-analysis was performed with standard statistical methods and the prognostic significance of UCA1 in digestive system cancers was qualified. Elevated level of UCA1 indicated the poor clinical outcome for patients with digestive system cancers. It may serve as a new biomarker related to prognosis in digestive system cancers.

  9. Prognostic value of long non-coding RNA UCA1 in human solid tumors

    Science.gov (United States)

    Liu, Fang-teng; Zhu, Pei-qian; Luo, Hong-liang; Zhang, Yi; Qiu, Cheng

    2016-01-01

    Background Numerous studies have shown that the expression of UCA1 was aberrantly upregulated in various cancer types. High expression of UCA1 was reported to be associated with unfavorable prognosis in cancer patients. Results A total of 1240 patients from 15 articles were included. The results indicated that a significantly shorter OS was observed in patients with high expression level of UCA1 (HR = 1.71, 95% CI: 1.43–1.99), in the subgroup analysis, the association was also observed in patients with cancers of digestive system (HR = 2.12, 95% CI: 1.59–2.66). Statistical significance was also observed in subgroup meta-analysis stratified by the cancer type, cut-off value, analysis type and sample size. Furthermore, poorer DFS was observed in patients with high expression level of UCA1 (HR = 2.54; 95% CI: 1.09–4.00). Additionally, the pooled odds ratios (ORs) showed that increased UCA1 was also related to positive lymph node metastasis (OR = 2.98, 95% CI: 2.06–4.30), distant metastasis (OR = 3.14, 95% CI: 1.77–5.58) and poor clinical stage (OR = 2.76, 95% CI: 2.08–3.68). Materials and Methods A comprehensive retrieval was conducted in multiple databases, including PubMed, Embase, Web of Science and CNKI. We collected relevant articles to explore the association between the expression levels of UCA1 and prognosis. Conclusions High expression level of UCA1 was associated with poor clinical outcome. UCA1 could serve as a novel biomarker for prognosis and might be a potential predictive factor for clinicopathological characteristics in various cancers. Further studies should be performed to verify the clinical utility of UCA1 in human solid tumors. PMID:27517147

  10. Hemigrapsus sanguineus in Long Island salt marshes: experimental evaluation of the interactions between an invasive crab and resident ecosystem engineers

    Directory of Open Access Journals (Sweden)

    Bradley J. Peterson

    2014-07-01

    Full Text Available The invasive Asian shore crab, Hemigrapsus sanguineus, has recently been observed occupying salt marshes, a novel environment for this crab species. As it invades this new habitat, it is likely to interact with a number of important salt marsh species. To understand the potential effects of H. sanguineus on this ecosystem, interactions between this invasive crab and important salt marsh ecosystem engineers were examined. Laboratory experiments demonstrated competition for burrows between H. sanguineus and the native fiddler crab, Uca pugilator. Results indicate that H. sanguineus is able to displace an established fiddler crab from its burrow. Feeding experiments revealed that the presence of H. sanguineus has a significantly negative impact on the number as well as the biomass of ribbed mussels (Geukensia demissa consumed by the green crab, Carcinus maenas, although this only occurred at high predator densities. In addition, when both crabs foraged together, there was a significant shift in the size of mussels consumed. These interactions suggests that H. sanguineus may have long-term impacts and wide-ranging negative effects on the saltmarsh ecosystem.

  11. A MISO UCA Beamforming Dimmable LED System for Indoor Positioning

    Directory of Open Access Journals (Sweden)

    Attaphongse Taparugssanagorn

    2014-01-01

    Full Text Available The use of a multiple input single output (MISO transmit beamforming system using dimmable light emitting arrays (LEAs in the form of a uniform circular array (UCA of transmitters is proposed in this paper. With this technique, visible light communications between a transmitter and a receiver (LED reader can be achieved with excellent performance and the receiver’s position can be estimated. A hexagonal lattice alignment of LED transmitters is deployed to reduce the coverage holes and the areas of overlapping radiation. As a result, the accuracy of the position estimation is better than when using a typical rectangular grid alignment. The dimming control is done with pulse width modulation (PWM to obtain an optimal closed loop beamforming and minimum energy consumption with acceptable lighting.

  12. Silence of long noncoding RNA UCA1 inhibits malignant proliferation and chemotherapy resistance to adriamycin in gastric cancer.

    Science.gov (United States)

    Shang, Chao; Guo, Yan; Zhang, Jiaxing; Huang, Baojun

    2016-05-01

    Urothelial carcinoma associated 1 (UCA1) gene is a long noncoding RNA (lncRNA), which shows expression and function abnormality in some kinds of malignant cancers. This study aimed to investigate its clinical significance and to examine its regulative effects of malignant proliferation and chemosensitivity to doxorubicin in gastric cancer cells. The expression of UCA1 was detected by quantitative real-time PCR. Statistical analysis was used to determine the relationship between UCA1 expression and clinical features and the prognostic value of UCA1 for disease-free survival. MTT assay was used to detect cell proliferation ability and chemosensitivity. Dual-color flow cytometric method was used to detect cell apoptosis. The expression of cleaved PARP and Bcl-2 protein was examined by Western blot. UCA1 was highly expressed in gastric cancer tissues and cells, and its high expression level had a positive correlation with some malignant pathological characteristics of gastric cancer, such as higher grade and poor differentiation. Moreover, UCA1 was an independent prognostic biomarker of disease-free survival for gastric cancer patients. Silence of UCA1 could significantly inhibit the cell proliferation of gastric cancer BGC-823 and SGC7901 cells. The chemotherapy resistance to adriamycin of SGC7901/ADR cells was depressed by UCA1 silence, and IC50 for adriamycin presented a conspicuous depression. UCA1 silence advanced apoptosis induced by adriamycin in SGC7901/ADR cells, up-regulated cleaved PARP protein expression and depressed the expression of anti-apoptosis protein Bcl-2. These results demonstrated that chemotherapy resistance changes induced by UCA1 silence might be mediated by the cell apoptosis pathway. In summary, lncRNA UCA1 was an independent prognostic biomarker of disease-free survival in gastric cancer patients and acted as an oncogene to regulate the malignant proliferation and resistance to adriamycin in gastric cancer cells. UCA1 might provide a new

  13. Crab Meat with Potherb Mustard

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Ingredients: Eight fresh crab. 75 grams of potherb mustard, two egg whites, scallions, ginger and cooking wine. Salt to the taste. Directions: 1. Slice and deep fry the potherb mustard till crisp. Place fried mustard on plate. 2. Steam the crab and remove meat. Stir fry meat with scallions, ginger, cooking wine and salt, Return meat to crab shells. 3. Beat egg white until stiff. Cover the crab meat with mixture and garnish. Steam meat for a few minutes. 4. Place the crab shells on fried mustard and serve. This attractive red and white dish features delicious crab meat with savory crisp mustard leaves.

  14. The UCA1/miR-204/Sirt1 axis modulates docetaxel sensitivity of prostate cancer cells.

    Science.gov (United States)

    Wang, Xu; Yang, Bo; Ma, Baojing

    2016-11-01

    In this study, we firstly investigated the regulative effect of miR-204 on Sirt1 expression in prostate cancer cells. Then, we examined whether miR-204 downregulation in the cells is a result of UCA1 upregulation. In addition, the regulative effect of UCA1/miR-204/Sirt1 axis on docetaxel sensitivity of prostate cancer cells was studied. QRT-PCR was performed to detect UCA1, miR-204 and Sirt1 mRNA expression. Western blot assay was performed to assess Sirt1, P-gp and caspase-3 expression. The regulative effect of UCA1/miR-204/Sirt1 axis on docetaxel sensitivity of prostate cancer cells was examined by measurement of docetaxel IC50, dictation of cleaved caspase-3 and flow cytometric analysis of cell apoptosis. MiR-204 negatively modulated Sirt1 expression in prostate cancer cells. UCA1 upregulation directly resulted in decreased miR-204 expression. UCA1 overexpression resulted in increased Sirt1 expression in PNT2 cells, while knockdown of endogenous UCA1 led to decreased Sirt1 in LNCaP and 22RV1 cells. UCA1 siRNA, Sirt1 siRNA and miR-204 mimics could enhance docetaxel-induced activation of caspase-3 and cell apoptosis in 22RV1/DR cells. There is a UCA1/miR-204/Sirt1 axis in LNCaP and 22RV1 cells. The UCA1/miR-204/Sirt1 axis plays an important role in modulating in vitro docetaxel sensitivity of the prostate cancer cells.

  15. Differential expression profile analysis of lncRNA UCA1α regulated mRNAs in bladder cancer.

    Science.gov (United States)

    Wang, Yu; Zhang, Hong; Li, Xu; Chen, Wei

    2017-08-16

    Urothelial carcinoma associated 1α (UCA1α) is a novel long non-coding RNA (lncRNA) that regulates bladder cancer proliferation, migration, and invasion. The target genes of UCA1α have, however, not been identified. To address this, a pCDNA3.1(+)-UCA1α over-expression vector was transfected into UM-UC-2 bladder cancer cells. Genes differentially expressed between pCDNA3.1(+)-UCA1α and pCDNA3.1(+) transfected cell were then detected by microarray and bioinformatics analysis. A total of 71 differentially expressed genes were identified, including 52 up-regulated genes and 19 down-regulated genes. As expected, the lncRNA UCA1α expression level was significantly increased when compared to that of pCDNA3.1(+) transfected cells. The five most significantly up-regulated and five most significantly down-regulated genes were selected, and their expression levels were also assessed by real time quantitative polymerase chain reaction and Western blot. The mRNA and protein expression levels of FOXI3 and GSTA3 were found to be significantly increased, and those of MED18 and TEX101 were found to be significantly decreased. Gene ontology (GO) clustering identified several significant biological processes, cellular components, and molecular functions, associated with lncRNA UCA1α over-expression. The differentially expressed genes were involved in several significant pathways as shown by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway clustering. Cell proliferation activity was significantly increased following overexpression of lncRNA UCA1α increasing over culture time. The present study identifies, for the first time, potential target genes for lncRNA UCA1α in bladder cancer, and provides a significant reference for studying the role of lncRNA UCA1α in bladder cancer. © 2017 Wiley Periodicals, Inc.

  16. The variable Crab Nebula

    CERN Document Server

    Tavani, Marco

    2011-01-01

    The remarkable Crab Nebula is powered by an energetic pulsar whose relativistic wind interacts with the inner parts of the Supernova Remnant SN1054. Despite low-intensity optical and X-ray variations in the inner Nebula, the Crab has been considered until now substantially stable at X-ray and gamma-ray energies. This paradigm has been shattered by the AGILE discovery in September 2010 of a very intense transient gamma-ray flare of nebular origin. For the first time, the Crab Nebula was "caught in the act" of accelerating particles up to 10^15 eV within the shortest timescale ever observed in a cosmic nebula (1 day or less). Emission between 50 MeV and a few GeV was detected with a quite hard spectrum within a short timescale. Additional analysis and recent Crab Nebula data lead to identify a total of four major flaring gamma-ray episodes detected by AGILE and Fermi during the period mid-2007/mid-2011. These observations challenge emission models of the pulsar wind interaction and particle acceleration process...

  17. Target Detection Is Enhanced by Polarization Vision in a Fiddler Crab.

    Science.gov (United States)

    How, Martin J; Christy, John H; Temple, Shelby E; Hemmi, Jan M; Marshall, N Justin; Roberts, Nicholas W

    2015-12-01

    We are constantly surprised by the ability of relatively simple animals to perform precise visually guided movements within complex visual scenes, often using eyes with limited resolution. Exceptional examples include the capture of airborne prey by dragonflies, the learning flights of bees and wasps, and the tracking of conspecifics by crabs on intertidal mudflats. Most studies have focused on how animals do this using sensitivity to intensity or color. However, it is increasingly evident that a third ability, polarization vision, may contribute to such tasks. In many insects, polarization-sensitive photoreceptors are confined within an area of the eye known as the dorsal rim, which detects the polarized sky pattern specifically for navigation. However, some animals, including fiddler crabs, are sensitive to the polarization of light across the majority of their image-forming eyes, potentially allowing them to use polarization information to increase perceived contrast for general visual tasks. Investigations into the use of polarization image-parsing by animals have largely been confined to laboratory settings under artificial lighting. This approach can occasionally mislead if the lighting conditions are different from natural. This study presents the first behavioral evidence from the natural context for a function of polarization image parsing. Using experimental manipulations in wild populations of the fiddler crab Uca stenodactylus, we provide evidence that these animals use their polarization vision to enhance contrast in their visual environment, thereby increasing their ability to detect and respond to objects on the mudflat surface.

  18. LncRNA-UCA1 exerts oncogenic functions in non-small cell lung cancer by targeting miR-193a-3p.

    Science.gov (United States)

    Nie, Wei; Ge, Hui-juan; Yang, Xiao-qun; Sun, Xiangjie; Huang, Hai; Tao, Xia; Chen, Wan-sheng; Li, Bing

    2016-02-01

    Recently, the long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been identified as an oncogenic gene in multiple human tumor entitles, and dysregulation of UCA1 was tightly linked to carcinogenesis and cancer progression. However, whether the aberrant expression of UCA1 in non-small cell lung cancer (NSCLC) is associated with malignancy, metastasis or prognosis has not been characterized. In this study, we found that UCA1 was upregulated in NSCLC tissues. Higher expression of UCA1 led to a significantly poorer survival time, and multivariate analysis revealed that UCA1 was an independent risk factor of prognosis. UCA1 overexpression enhanced, whereas UCA1 silencing impaired the proliferation and colony formation of NSCLC cells. Moreover, mechanistic investigations showed that UCA1 upregulated the expression of miR-193a-3p target gene ERBB4 through competitively 'spongeing' miR-193a-3p. Overall, we concluded that UCA1 functions as an oncogene in NSCLC, acting mechanistically by upregulating ERBB4 in part through 'spongeing' miR-193a-3p.

  19. Nuevos retos para la enseñanza de la arquitectura en la UCA

    Directory of Open Access Journals (Sweden)

    Martín Majewsky

    2004-02-01

    Full Text Available La Facultad de Ciencia, Tecnología y Ambiente de la UCA, desde su experiencia académica e investigativa, propone la inserción de un plan de estudio para la enseñanza de la Arquitectura, brindando alternativas de solución a los problemas del entorno espacial, producto del deterioro social, económico y ambiental.

  20. 50 CFR Table 9 to Part 680 - Initial Issuance of Crab PQS by Crab QS Fishery

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Initial Issuance of Crab PQS by Crab QS... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 680, Table 9 Table 9 to Part 680—Initial Issuance of Crab PQS by Crab QS Fishery Column A:For each crab QS fishery: Column B:The Regional Administrator shall calculate...

  1. 50 CFR Table 7 to Part 680 - Initial Issuance of Crab QS by Crab QS Fishery

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Initial Issuance of Crab QS by Crab QS... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 680, Table 7 Table 7 to Part 680—Initial Issuance of Crab QS by Crab QS Fishery Column A: Crab QS Fisheries Column B: Qualifying Years for QS Column C: Eligibility...

  2. Hairy Crab Arrives at Zen

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The best time for feasting on hairy crab is only for a short period of time in autumn,so don’t miss out on this unparalleled delicacy. Zen has prepared a variety of dishes made from the crab. Gift boxes and gift vouchers are also available for your friends and family.

  3. Crab Cavities for Linear Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Ambattu, P.; Carter, R.; Dexter, A.; Tahir, I.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Beard, C.; Dykes, M.; Goudket, P.; Kalinin, A.; Ma, L.; McIntosh, P.; /Daresbury; Shulte, D.; /CERN; Jones, Roger M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Bellantoni, L.; Chase, B.; Church, M.; Khabouline, T.; Latina, A.; /Fermilab; Adolphsen, C.; Li, Z.; Seryi, Andrei; /SLAC

    2011-11-08

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  4. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  5. Estrutura populacional de Uca maracoani (Decapoda, Brachyura, Ocypodidae no Baixio Mirim, Baía de Guaratuba, Paraná Population structure of Uca maracoani (Decapoda, Brachyura, Ocypodidae from the tidal flat of Baixio Mirim, Guaratuba Bay, Parana State, Brazil

    Directory of Open Access Journals (Sweden)

    Mariângela Di Benedetto

    2009-12-01

    Full Text Available Um estudo sobre a flutuação anual da abundância, composição de tamanho dos indivíduos, proporção de sexos, período reprodutivo e de recrutamento dos juvenis de uma população de Uca maracoani (Latreille, 1802-1803 foi realizado no Baixio Mirim, Baía de Guaratuba, Paraná (48º36'W e 25º52'S. Os animais foram coletados mensalmente, de fevereiro/2005 a janeiro/2006, durante as marés baixas de sizígia, e a sua largura da carapaça (LC medida. A temperatura pontual do ar variou de 17 a 29ºC, a luminosidade de 8.740 a 151.300 lux, a salinidade de 8 a 25 e a temperatura do solo (superfície, 5 cm, 10 cm, 15 cm e 20 cm de profundidade de 18,3 a 28,9ºC. Foram analisados 7.120 indivíduos, dos quais, 2.578 juvenis sexualmente indefinidos, 2.377 machos e 2.165 fêmeas. A abundância da população variou de 341 (abril a 994 indivíduos (janeiro, mas a sua flutuação anual não esteve relacionada com a das variáveis abióticas estudadas. A proporção de sexos foi de 1:1 e a reprodução da espécie é do tipo contínuo, com dois picos de intensidade: um em abril e outro em novembro. O recrutamento de juvenis, também, é contínuo com dois períodos mais intensos no ano, um em julho e outro em dezembro-janeiro. A LC da população variou de 1,14 a 2,62 mm para juvenis sexualmente indefinidos, 2,58 a 17,83 mm para machos juvenis, 2,60 a 11,72 mm para fêmeas juvenis, 17,85 a 35,81 mm para machos maduros e 11,75 a 31,76 mm para fêmeas maduras. Os machos atingem tamanhos maiores do que as fêmeas.A study about the annual fluctuation of the abundance, size composition, sexual proportion, reproductive period and juvenile recruitment of the fiddler crab Uca maracoani (Latreille, 1802-1803 was carried out in a population living in a tidal flat at Guaratuba Bay, Parana State, Brazil (48º36'W e 25º52'S. Crabs were obtained from February 2005 to January 2006, during low spring tides, in monthly collections, and their carapace width was measured

  6. The Martyrs of the UCA: demand and grace. Social commitment of the Catholic University

    Directory of Open Access Journals (Sweden)

    Jon Sobrino, SJ

    2010-12-01

    Full Text Available Hace veinte años asesinaron a mis hermanos jesuitas de la UCA, a Julia Elba y a Celina. Yo me encontraba en Tailandia, y a mi regreso a El Salvador tenía que pasar por San Francisco. En el aeropuerto me esperaban –con rostros impávidos- Steve Prevett y Peggy O’Grady. En las calles de San Francisco, con un parlante en la mano, Paul Locatelli condenaba los asesinatos, Tessa Rouverol le acompañaba.

  7. Joint estimation of DOA, frequency, and polarization based on cumulants and UCA

    Institute of Scientific and Technical Information of China (English)

    Huang Jiacai; Shi Yaowu; Tao Jianwu

    2007-01-01

    A joint estimation algorithm of direction of arrival (DOA), frequency, and polarization, based on fourth-order cumulants and uniform circular array (UCA) of trimmed vector sensors is presented for narrowband non-Gaussian signals. The proposed approach, which is suitable for applications in arbitrary Gaussian noise environments, gives a closed-form representation of the estimated parameters, without spectral peak searching. An efficient method is also provided for elimination of cyclic phase ambiguities. Simulations are presented to show the performance of the algorithm.

  8. The Martyrs of the UCA: demand and grace. Social commitment of the Catholic University

    OpenAIRE

    Jon Sobrino, SJ

    2010-01-01

    Hace veinte años asesinaron a mis hermanos jesuitas de la UCA, a Julia Elba y a Celina. Yo me encontraba en Tailandia, y a mi regreso a El Salvador tenía que pasar por San Francisco. En el aeropuerto me esperaban –con rostros impávidos- Steve Prevett y Peggy O’Grady. En las calles de San Francisco, con un parlante en la mano, Paul Locatelli condenaba los asesinatos, Tessa Rouverol le acompañaba.

  9. Golden Crab Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In November 1995, a voluntary logbook program for the golden crab fishery in the waters under the jurisdiction of the South Atlantic Fishery Management Council...

  10. Antarctic crabs: invasion or endurance?

    Science.gov (United States)

    Griffiths, Huw J; Whittle, Rowan J; Roberts, Stephen J; Belchier, Mark; Linse, Katrin

    2013-01-01

    Recent scientific interest following the "discovery" of lithodid crabs around Antarctica has centred on a hypothesis that these crabs might be poised to invade the Antarctic shelf if the recent warming trend continues, potentially decimating its native fauna. This "invasion hypothesis" suggests that decapod crabs were driven out of Antarctica 40-15 million years ago and are only now returning as "warm" enough habitats become available. The hypothesis is based on a geographically and spatially poor fossil record of a different group of crabs (Brachyura), and examination of relatively few Recent lithodid samples from the Antarctic slope. In this paper, we examine the existing lithodid fossil record and present the distribution and biogeographic patterns derived from over 16,000 records of Recent Southern Hemisphere crabs and lobsters. Globally, the lithodid fossil record consists of only two known specimens, neither of which comes from the Antarctic. Recent records show that 22 species of crabs and lobsters have been reported from the Southern Ocean, with 12 species found south of 60 °S. All are restricted to waters warmer than 0 °C, with their Antarctic distribution limited to the areas of seafloor dominated by Circumpolar Deep Water (CDW). Currently, CDW extends further and shallower onto the West Antarctic shelf than the known distribution ranges of most lithodid species examined. Geological evidence suggests that West Antarctic shelf could have been available for colonisation during the last 9,000 years. Distribution patterns, species richness, and levels of endemism all suggest that, rather than becoming extinct and recently re-invading from outside Antarctica, the lithodid crabs have likely persisted, and even radiated, on or near to Antarctic slope. We conclude there is no evidence for a modern-day "crab invasion". We recommend a repeated targeted lithodid sampling program along the West Antarctic shelf to fully test the validity of the "invasion hypothesis".

  11. On the Crab Proper Motion

    CERN Document Server

    Caraveo, P A; Caraveo, Patrizia A; Mignani, Roberto

    1998-01-01

    Owing to the dramatic evolution of telescopes as well as optical detectors in the last 20 yrs, we are now able to measure anew the proper motion of the Crab pulsar, after the classical result of Wyckoff and Murray (1977) in a time span 40 times shorter. The proper motion is aligned with the axis of symmetry of the inner Crab nebula and, presumably, with the pulsar spin axis.

  12. Caught in the Crab's claws

    CERN Multimedia

    2001-01-01

    'The crab', a new cryo magnet transport vehicle, starts work at CERN. Produced by the ESI group of EST division and built in Finland, it has the job of transporting LHC magnets in buildings SM18 and SMA18. If you see a huge crab scuttling around building SMA18 don't be afraid! It is the new Cryo Magnet Transport Vehicle produced by the ESI group (Engineering Support for Infrastructure, EST Division) for CERN's LHC project and built by Finnish Company ROCLA. This orange vehicle, nicknamed 'The Crab', is perhaps the strangest piece of equipment used for the construction of LHC magnets. It will start work at the end of this month. The crab will be used to transport LHC cryo-magnets and their components in the assembly and preparation building, SMA18, and test building, SM18. It has many capabilities that will allow CERN staff and contractors transport magnets between the two buildings and to locate them in the right position on the test beds. The crab in action during its first tests on 8 February. How does th...

  13. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  14. Are Crab Nanoshots Schwinger Sparks?

    CERN Document Server

    Stebbins, Albert

    2015-01-01

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum $e^{\\pm}$ pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, $\\sim 10^3 L_{\\astrosun}$, 10 PeV $e^{\\pm}$ accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than $1 m^3$ and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. This mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  15. LHC crab-cavity aspects and strategy

    Energy Technology Data Exchange (ETDEWEB)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-05-23

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  16. Wind power communication design and implementation of test environment for IEC61850/UCA2

    Energy Technology Data Exchange (ETDEWEB)

    Johnsson, A.; Svensson, J.

    2002-04-01

    Elforsk has sponsored a joint Swedish-Danish project aiming at finding and recommend a common solution for communication with wind power plants. The first stage of the work resulted in a requirement specification Functional Requirements on Communication System for Wind Turbine Applications. During the project a number of possible communication solutions were identified. The two most promising solutions have been tested in order to verify to what extent they fulfil the requirements in the specification. A version of the IEC 61850 standard based on the communication protocol MMS, has been tested at a wind power plant at Gotland, Sweden, and an OPC-interface has been tested in Denmark. This report includes a description of the design choices made for the test implementation of MMS, as well as a detailed description of the implementation of the IEC 61850/UCA2 software including information models and information exchange services. (BA)

  17. Wind power communication design and implementation of test environment for IEC61850/UCA2

    Energy Technology Data Exchange (ETDEWEB)

    Johnsson, A.; Svensson, J.

    2002-04-01

    Elforsk has sponsored a joint Swedish-Danish project aiming at finding and recommend a common solution for communication with wind power plants. The first stage of the work resulted in a requirement specification Functional Requirements on Communication System for Wind Turbine Applications. During the project a number of possible communication solutions were identified. The two most promising solutions have been tested in order to verify to what extent they fulfil the requirements in the specification. A version of the IEC 61850 standard based on the communication protocol MMS, has been tested at a wind power plant at Gotland, Sweden, and an OPC-interface has been tested in Denmark. This report includes a description of the design choices made for the test implementation of MMS, as well as a detailed description of the implementation of the IEC 61850/UCA2 software including information models and information exchange services. (BA)

  18. Estructura del aparato reproductor masculino de Uca uruguayensis (Decapoda, Ocypodidae Structure of the male reproductive tract of Uca uruguayensis (Decapoda, Ocypodidae

    Directory of Open Access Journals (Sweden)

    Elena Irene Cuartas

    Full Text Available El objetivo de este trabajo es describir las estructuras del sistema reproductor de machos de Uca uruguayensis Nobili, 1901 y estudiar los cambios relacionados con la madurez sexual. Se trabajó con observación estereoscópica de material fresco, técnica histológica de rutina y observaciones en Microscopio Electrónico de Barrido. Se incluyó la caracterización de los gonopodos 1 (G1 y 2 (G2. El tracto reproductor del macho se compone de un par de testículos (T, un vaso deferente (VD tubular y sinuoso y una ampolla terminal (AT. El VD tiene tres secciones, la anterior (VDA, la media (VDM y la posterior (VDP. El VDA y VDM están conformadas por un epitelio simple de células cúbicas. El epitelio del VDP es columnar y con núcleos basales y alongados. El diseño tubular se modifica al ocuparse el lumen del VDP con líquido espermático durante el verano y la musculatura circular se hace más evidente. La porción terminal del VDP se ensancha formando una ampolla (AT que comprende cuatro cámaras interconectadas. Todas las estructuras están rodeadas de una capa de tejido conectivo de poco espesor. Se identifican las modificaciones observadas en la histología de T y VD, definiendo como mas relevantes las observadas desde el mes de noviembre hasta marzo. Estas modificaciones sugieren que U. uruguayensis tiene, en la localidad estudiada, una única estación reproductiva durante el verano en esta latitud. La AT, tal como es descripta, es una estructura que hasta el momento no ha sido mencionada para los Brachyura.The structure of the male reproductive tract was described in Uca uruguayensis Nobili, 1901, by using histological methods, scanning electron microscopy techniques, and stereoscopic observations of fresh material. The aim of this work was to establish the functional changes associated with sexual maturation. The morphology of the first (G1 and second (G2 pair of gonopods was described. The male reproductive tract consists of paired

  19. Crab shedding-system designs

    OpenAIRE

    1997-01-01

    There are as many ways to build and arrange crab shedding setups as there are people who make them. The following drawings are suggestions based on the experiencesof successful shedders. You may find changes that suit your operation better. (8pp.)

  20. UCA1基因新剪接变异体全长cDNA序列的克隆%Cloning of the full-length cDNA sequence of a novel human UCA1 spliced variant

    Institute of Scientific and Technical Information of China (English)

    王宇; 陈葳; 李旭

    2012-01-01

    Objective To clone the full-length cDNA sequence of novel UCA1 spliced isoforms for understanding the exact mechanism of this type of alternative splicing. Methods The full-length cDNA was amplified from BLZ-211 cells by using the in silicon sequence elongation technique, 5'-RACE and 3'-RACE techniques. Products of RT-PCR were sequenced and further assembled. Results The new UCA1 spliced isoform sequence was 2 202 bp. Conclusion A combination of the in silicon sequence elongation, 5'-RACE and 3'-RACE techniques is an effective way to obtain the full-length cDNA, which will guide further research on the mechanism of this type of alternative splicing.%目的 克隆新的UCA1剪接变异体全长cDNA序列,为研究其可变剪接机制奠定基础.方法 用电子克隆技术和cDNA序列末端快速扩增技术(rapid amplification of cDNA ends,RACE)扩增细胞系BLZ-211 cDNA并进行产物测序和序列拼接.结果 新克隆的UCA1剪接变异体全长cDNA序列为2 202 bp.结论 综合采用电子克隆技术与RACE技术是获得全长cDNA序列的有效方法,为该基因的后续可变剪接机制的研究奠定了基础.

  1. AFSC/RACE/SAP/Jensen: Bitter crab disease mortality in SE Alaska Tanner crab

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These are data from a laboratory experiment in which wild caught male Tanner crab (Chionoecetes bairdi) from Stephens Passage, SE Alaska were held to evaluate crab...

  2. Final focus designs for crab waist colliders

    Science.gov (United States)

    Bogomyagkov, A.; Levichev, E.; Piminov, P.

    2016-12-01

    The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the DA Φ NE collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs with the crab waist collision scheme for already existent collider DA Φ NE and SuperKEKB, presently undergoing commissioning, for the projects of SuperB in Italy, CTau in Novosibirsk and FCC-ee at CERN.

  3. The Crab Nebula flaring activity

    Directory of Open Access Journals (Sweden)

    G. Montani

    2014-12-01

    Full Text Available The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼1015 cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼109, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  4. The Crab Nebula flaring activity

    Energy Technology Data Exchange (ETDEWEB)

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  5. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Hall, B. [Lancaster Univ. (United Kingdom); Burt, G. [Lancaster Univ. (United Kingdom); Smith, J. D.A. [Lancaster Univ. (United Kingdom); Rimmer, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, H. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Delayen, J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Calaga, R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2009-05-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme but the frequency cannot be increased any higher due to the long bunch length of the LHC beam. This will require a novel compact crab cavity design. A superconducting version of a two rod coaxial deflecting cavity as a suitable design is proposed in this paper.

  6. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA (color)

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This colorful photo shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  7. Brachyuran crab community structure and associated sediment reworking activities in pioneer and young mangroves of French Guiana, South America

    Science.gov (United States)

    Aschenbroich, Adélaïde; Michaud, Emma; Stieglitz, Thomas; Fromard, François; Gardel, Antoine; Tavares, Marcos; Thouzeau, Gérard

    2016-12-01

    This study in French Guiana evaluates the changes of crab assemblages and their bioturbation activities between mangrove early stages (pioneer and young mangrove) and within stages by taking their spatial heterogeneity (tidal channels, flat areas, pools) into account. The results show differences in crab assemblage structure between and within the early stages of mangrove in relation to microhabitat and sediment characteristics. The sediment reworking rates are a function of the biomass or density of particular species (Ucides cordatus, Uca cumulanta) and burrower functional groups. Crab species or functional interactions mediate changes in sediment reworking rates suggesting the need to consider entire benthic communities rather than single species. This study suggests that the role of the microhabitat in determining the biologically-induced sediment reworking rates depends on the age of the mangrove. Feeding activity results in a sediment turnover of 11.7 ± 9.7 gdw m-2 day-1 and 6.8 ± 3.0 gdw m-2 day-1 in the pioneer and young mangroves, respectively. Burrow maintenance excavates 40.5 ± 7.4 gdw m-2 day-1 and 251.3 ± 419.7 gdw m-2 day-1 in the pioneer and young mangroves, respectively. Upscaling to the studied area (Sinnamary estuary: 6 km2), shows that 500 tons.day-1 and 20 tons.day-1 of sediments could be excavated and pelletized, respectively, during the spring tides of the dry season. Thus, biological sediment reworking would greatly contribute to the sedimentary dynamics of the Guianese mangroves under Amazonian influence.

  8. Most Detailed Image of the Crab Nebula

    Science.gov (United States)

    2005-01-01

    This new Hubble image -- one among the largest ever produced with the Earth-orbiting observatory -- shows the most detailed view so far of the entire Crab Nebula ever made. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest image ever taken with Hubble's WFPC2 workhorse camera. The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope and is the highest resolution image of the entire Crab Nebula ever made.

  9. Flux of crab larvae in a mangrove creek in the Gulf of Nicoya, Costa Rica

    Science.gov (United States)

    Dittel, A. I.; Epifanio, C. E.; Lizano, O.

    1991-02-01

    Transport of crab zoeae, megalopae, and early juveniles was measured in a mangrove estero (creek) in the Gulf of Nicoya on the Pacific coast of Costa Rica. In 1987, larvae were collected by quantitative pumping from a platform moored in the mouth of the estero. During each sampling period, larvae were collected every 2 h over five consecutive tidal cycles. The investigation consisted of one spring-tide sampling period and one neap-tide sampling period during each season of the year (dry season, dry-rainy transition, rainy season, and rainy-dry transition). Hourly tidal heights were available for each sampling period. A model for hindcasting tidal volume flux from the change in sea level over each half tidal cycle was developed from measurements made in the estero in 1989. This model was used to calculate tidal volume flux and consequent larval flux during each of the 1987 sampling periods. There was a net export of zoea stage I of four taxonomic groups ( Uca spp., Pinnotheres spp., Petrolistes spp., and Grapsidae) during most sampling periods, while there was a net import of zoea stage I of only two groups ( Pinnixa spp. and Xanthidae). Intermediate and late zoeal stages of all taxonomic groups were generally imported into the estero, as were megalopal and juvenile stages. Quantitative estimates of net larval transport corroborated earlier qualitative models of larval transport that had been based on observations of the vertical distribution of larvae in the water column.

  10. 50 CFR 680.6 - Crab economic data report (EDR).

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab economic data report (EDR). 680.6... General § 680.6 Crab economic data report (EDR). Persons participating in the CR crab fisheries are... complete. Use these tables to complete the EDRs described in this section: Table 1, Crab...

  11. Long Non-Coding RNA (LncRNA) Urothelial Carcinoma Associated 1 (UCA1) Increases Multi-Drug Resistance of Gastric Cancer via Downregulating miR-27b

    Science.gov (United States)

    Fang, Qun; Chen, XiaoYan; Zhi, XuTing

    2016-01-01

    Background In this study, we aimed to investigate the association between UCA1 and miR-27b in gastric cancer and further study their involvement in multi-drug resistance (MDR) of gastric cancer. Material/Methods The microarray data of dysregulated lncRNAs in gastric cancer tissues was retrieved in the GEO dataset. QRT-PCR analysis was performed to assess UCA1 expression based on 28 paired cancerous and peritumoral normal tissues. The human gastric cancer cell line SGC-7901, and SGC-7901 derived Adriamycin (doxorubicin) resistant SGC-7901/ADR, cisplatin resistant SGC-7901/DDP, and 5-FU resistant SGC-7901/FU cells were used as in vitro cell models to assess the effect of UCA1 and miR-27b on MDR. Results UCA1 was significantly upregulated in the cancerous tissues and its expression was negatively correlated with miR-27b expression level. Inhibition of UCA1 significantly restored miR-27b expression in MDR gastric cancer cells. UCA1 knockdown and miR-27b overexpression reduced IC50 of ADR, DDP, and 5-FU in SGC-7901/ADR cells and increased ADR induced cell apoptosis. UCA1 overexpression and miR-27b inhibition increased the IC50 of ADR, DDP, and 5-FU in SGC-7901 cells and reduced ADR induced cell apoptosis. Western blot analysis showed that UCA1 knockdown and miR-27b overexpression also decreased anti-apoptotic protein BCL-2 and increased apoptotic protein cleaved caspase-3. Conclusions UCA1 is negatively correlated with miR-27b expression in gastric cancer tissue. Knockdown of UCA1 restored miR-27b expression in gastric cancer cells. The UCA1-miR-27b axis was involved in regulation of chemosensitivity of gastric cancer cells. PMID:27694794

  12. Effects of urban wastewater on crab and mollusc assemblages in equatorial and subtropical mangroves of East Africa

    Science.gov (United States)

    Cannicci, Stefano; Bartolini, Fabrizio; Dahdouh-Guebas, Farid; Fratini, Sara; Litulo, Carlos; Macia, Adriano; Mrabu, Elisha J.; Penha-Lopes, Gil; Paula, José

    2009-09-01

    Mangrove forests are known to accomplish crucial ecosystem functions and services. They are nursery areas for fish, prawns and crabs, which provide coastal communities with a variety of food, timber and chemicals, and protect coasts from catastrophic events, such as tsunamis. Recently, a novel ecological service has been proposed for mangrove systems, namely natural wastewater treatment wetlands. This hypothesis was based on experimental data collected mainly in Chinese mangrove systems, which proved that mangrove soils were efficient in absorbing nutrients. Moreover, sewage loading seemed harmless to both plants and benthic communities in these systems. However, before promoting the use of natural mangroves as pollution buffers, or constructed mangrove wetlands as sewage treatment facilities, more data are needed on their overall tolerance to organic loading. Differences in macrobenthos patterns were thus investigated between peri-urban mangroves and sites not affected by sewage disposal in East Africa. We assessed differences in epifaunal assemblages, comprising crabs and molluscs, employing multivariate ACI unbalanced analyses to compare peri-urban mangrove swamps with those characteristic of non-urban mangroves with similar ecological traits. The sampling design was spatially nested, replicates being assessed at equatorial (southern Kenya) and subtropical (southern Mozambique) sites. The results manifested a consistent increase in crab biomass at the peri-urban sites in both Kenya and Mozambique. Moreover, the peri-urban systems were richer than the non-urban mangroves, both in terms of fiddler crabs ( Uca spp.) which feed on benthic microalgae and bacteria, and sesarmids, such as Perisesarma guttatum and Neosarmatium meinerti, which feed on both substratum and leaf litter. The abundance of gastropods, in contrast, decreased significantly, especially in Kenya, mainly due to the disappearance of the mud whelk Terebralia palustris. The results thus indicate that

  13. What brakes the Crab pulsar?

    Science.gov (United States)

    Čadež, A.; Zampieri, L.; Barbieri, C.; Calvani, M.; Naletto, G.; Barbieri, M.; Ponikvar, D.

    2016-03-01

    Context. Optical observations provide convincing evidence that the optical phase of the Crab pulsar follows the radio one closely. Since optical data do not depend on dispersion measure variations, they provide a robust and independent confirmation of the radio timing solution. Aims: The aim of this paper is to find a global mathematical description of Crab pulsar's phase as a function of time for the complete set of published Jodrell Bank radio ephemerides (JBE) in the period 1988-2014. Methods: We apply the mathematical techniques developed for analyzing optical observations to the analysis of JBE. We break the whole period into a series of episodes and express the phase of the pulsar in each episode as the sum of two analytical functions. The first function is the best-fitting local braking index law, and the second function represents small residuals from this law with an amplitude of only a few turns, which rapidly relaxes to the local braking index law. Results: From our analysis, we demonstrate that the power law index undergoes "instantaneous" changes at the time of observed jumps in rotational frequency (glitches). We find that the phase evolution of the Crab pulsar is dominated by a series of constant braking law episodes, with the braking index changing abruptly after each episode in the range of values between 2.1 and 2.6. Deviations from such a regular phase description behave as oscillations triggered by glitches and amount to fewer than 40 turns during the above period, in which the pulsar has made more than 2 × 1010 turns. Conclusions: Our analysis does not favor the explanation that glitches are connected to phenomena occurring in the interior of the pulsar. On the contrary, timing irregularities and changes in slow down rate seem to point to electromagnetic interaction of the pulsar with the surrounding environment.

  14. Alternative splicing in the fiddler crab cognate ecdysteroid receptor: variation in receptor isoform expression and DNA binding properties in response to hormone.

    Science.gov (United States)

    Durica, David S; Das, Sunetra; Najar, Fares; Roe, Bruce; Phillips, Barret; Kappalli, Sudha; Anilkumar, Gopinathan

    2014-09-15

    RXR cDNA cloning from three Uca species led to the identification of 4 conserved isoforms, indicative of alternative splicing in the hinge and ligand binding domains (LBD). Sequencing of overlapping clones from a Ucapugilator genomic library identified EcR isoforms matching previously identified cDNA variants; in addition, a cryptic exon in the LBD was detected and evidence for expression of this new isoform was obtained from next-generation sequencing. RNA-seq analysis also identified a new amino terminal EcR variant. EcR and RXR transcript abundance increases throughout ovarian maturation in U. pugilator, while cognate receptor transcript abundance remains constant in a related Indo-Pacific species with a different reproductive strategy. To examine if crab RXR LBD isoforms have different physical properties in vitro, electromobility shift assays were performed with different EcR isoforms. The cognate crab and fruit fly receptors differ in their responses to hormone. Ecdysteroids did not increase DNA binding for the crab heterodimers, while ecdysteroids stimulate binding for Drosophilamelanogaster EcR/USP heterodimers. In swapping experiments, UpEcR/USP heterodimers did not show ligand-responsive differences in DNA binding; both crab RXR LBD isoforms, however, conferred ligand-responsive increases in DNA binding with DmEcRs. These data indicate that both UpRXR LBD isoforms can heterodimerize with the heterologous DmEcR receptors and promote ligand and DNA binding. Unresponsiveness of the cognate receptors to ecdysteroid, however, suggest additional factors may be required to mediate endogenous, perhaps isoform-specific, differences in EcR conformation, consistent with previously reported effects of UpRXR isoforms on UpEcR ligand-binding affinities.

  15. Novel Geometries for the LHC CRAB Cavity

    CERN Document Server

    Hall, Ben

    2010-01-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme b...

  16. What brakes the Crab pulsar?

    CERN Document Server

    Čadež, A; Barbieri, C; Calvani, M; Naletto, G; Barbieri, M; Ponikvar, D

    2015-01-01

    Optical observations provide convincing evidence that the optical phase of the Crab pulsar follows the radio one closely. Since optical data do not depend on dispersion measure variations, they provide a robust and independent confirmation of the radio timing solution. The aim of this paper is to find a global mathematical description of Crab pulsar's phase as a function of time for the complete set of published Jodrell Bank radio ephemerides (JBE) in the period 1988-2014. We apply the mathematical techniques developed for analyzing optical observations to the analysis of JBE. We break the whole period into a series of episodes and express the phase of the pulsar in each episode as the sum of two analytical functions. The first function is the best-fitting local braking index law, and the second function represents small residuals from this law with an amplitude of only a few turns, which rapidly relaxes to the local braking index law. From our analysis, we demonstrate that the power law index undergoes "inst...

  17. Ultraviolet studies of the Crab Nebula

    Science.gov (United States)

    Talavera, A.

    2017-03-01

    The Crab Nebula (Messier 1) is one of the most observed sources with the XMM-Newton space telescope of ESA. The Crab and its related pulsar are a calibration source for the on-board X-rays cameras. There are around 80 observations between 2000 and 2015. In this observations, the XMM-Newton Optical and UV Monitor (OM) has also been used. We present a preliminary study of the Crab using images obtained the OM UV filters at 291, 231 and 212 nm. Photometric data for the pulsar (PSR0531+21), created in the supernova event of AD 1054 origin of the nebula, are also presented

  18. Design of the ILC Crab Cavity System

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, C.; Beard, C.; Bellantoni, L.; Burt, G.; Carter, R.; Chase, B.; Church, M.; Dexter, A.; Dykes, M.; Edwards, H.; Goudket, P; Jenkins, R.; Jones, R.M.; Kalinin,; Khabiboulline, T.; Ko, K.; Latina, A.; Li, Z.; Ma, L.; McIntosh, P.; Ng, C.; /SLAC /Daresbury /Fermilab /Cockcroft Inst. Accel. Sci. Tech. /CERN

    2007-08-15

    The International Linear Collider (ILC) has a 14 mrad crossing angle in order to aid extraction of spent bunches. As a result of the bunch shape at the interaction point, this crossing angle at the collision causes a large luminosity loss which can be recovered by rotating the bunches prior to collision using a crab cavity. The ILC baseline crab cavity is a 9-cell superconducting dipole cavity operating at a frequency of 3.9 GHz. In this paper the design of the ILC crab cavity and its phase control system, as selected for the RDR in February 2007 is described in fuller detail.

  19. Final focus designs for crab waist colliders

    CERN Document Server

    AUTHOR|(CDS)2084369; Levichev, Evgeny; Piminov, Pavel

    2016-01-01

    The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the DA$\\Phi$NE collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs with the crab waist collision scheme for already existent collider DA$\\Phi$NE and SuperKEKB, presently undergoing commissioning, for the projects of SuperB in Italy, CTau in Novosibirsk and FCC-ee at CERN.

  20. A large bubble around the Crab Nebula

    Science.gov (United States)

    Romani, Roger W.; Reach, William T.; Koo, Bon Chul; Heiles, Carl

    1990-01-01

    IRAS and 21 cm observations of the interstellar medium around the Crab nebula show evidence of a large bubble surrounded by a partial shell. If located at the canonical 2 kpc distance of the Crab pulsar, the shell is estimated to have a radius of about 90 pc and to contain about 50,000 solar masses of swept-up gas. The way in which interior conditions of this bubble can have important implications for observations of the Crab are described, and the fashion in which presupernova evolution of the pulsar progenitor has affected its local environment is described.

  1. Spin-rotation parameter Q for elastic scattering of 800 MeV polarized protons from WO, UCa, and SYPb

    Energy Technology Data Exchange (ETDEWEB)

    Fergerson, R.W.

    1985-10-01

    The spin-rotation parameter Q was measured for WO, UCa, and SYPb using the 800 MeV proton beam produced at the Clinton P. Anderson Meson Physics Facility. The experiment was carried out using the High Resolution Spectrometer equipped with a focal-plane polarimeter to determine the scattered polarization components in all three directions. These data (when combined with previous cross section and analyzing power data) determine the amplitude describing the elastic scattering of protons from these spin-zero nuclei to within an overall phase. Q is shown to be more sensitive than either the cross section or analyzing power to differences between the nonrelativistic and relativistic scattering theories that describe the proton-nucleus reaction in terms of fundamental proton-nucleon input. The nonrelativistic predictions for Q generally lie below the data but consistently have the correct structure. The relativistic predictions for the UCa and SYPb Q data are quite good (better than the nonrelativistic predictions). The relativistic predictions for the WO Q data show much more structure than is evident in the data. 51 refs., 39 figs., 4 tabs.

  2. Monitoring the Crab Nebula with LOFT

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    From 2008-2010, the Crab Nebula was found to decline by 7% in the 15-50 keV band, consistently in Fermi GBM, INTEGRAL IBIS, SPI, and JEMX, RXTE PCA, and Swift BAT. From 2001-2010, the 15-50 keV flux from the Crab Nebula typically varied by about 3.5% per year. Analysis of RXTE PCA data suggests possible spectral variations correlated with the flux variations. I will present estimates of the LOFT sensitivity to these variations. Prior to 2001 and since 2010, the observed flux variations have been much smaller. Monitoring the Crab with the LOFT WFM and LAD will provide precise measurements of flux variations in the Crab Nebula if it undergoes a similarly active episode.

  3. The Pulsar in the Crab Nebula

    CERN Document Server

    Lewandowska, Natalia

    2015-01-01

    The Crab pulsar belongs to one of the most studied stellar objects in the sky. Since its accidental detection in 1968, its pulsed emission has been observed throughout most of the electromagnetic spectrum. Although currently one of more than 2000 known pulsars, its way of work has remained not understood making the Crab pulsar an object of continuous studies and interest. Referring to the pulsed emission of the Crab pulsar only at radio wavelengths, it reveals a diversity of different phenomena. They range from deviations of the predicted slowing down process of the pulsar with time (long time phenomena) to an irregularity of its single pulse emission (short time phenomena). Similar and different kinds of deviations are observed at other wavelengths. Consequently, the Crab pulsar provides a large diversity of different emission characteristics which have remained difficult to interpret with a uniform theoretical approach including all observed properties. Since a review of all currently examined properties of...

  4. Crab Orchard National Wildlife Refuge : Sign Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Sign Plan explains how signs are used on the Refuge to help guide and educate visitors. An inventory of current signs is...

  5. Wakefield Damping for the CLIC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Ambattu, P.K.; Burt, G.; Dexter, A.C.; Carter, R.G.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Khan, V.; Jones, R.M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Dolgashev, V.; /SLAC

    2011-12-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  6. Crab Orchard National Wildlife Refuge : Hunting Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan provides guidelines for the administration of hunting activity and for the development, maintenance, and enforcement of regulations and guidelines on Crab...

  7. Characterization of a Freshwater Crab Sudanonautes aubryi ...

    African Journals Online (AJOL)

    SARAH

    2014-01-31

    Jan 31, 2014 ... J. Appl. Biosci. 2014. Characterization of fresh water crab ( Sudanonautes aubryi) of ... great diversity (Dobson, 2004), their role in the ecology of freshwaters is ... Apart from fish, other groups of animals subject to exploitation ...

  8. Epizoic and ectoparasitic protozoans from crab larvae

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    A suctorian, Ephelota gemmipara Hertwig, infesting the zoea of the peacrab, Porcellana and an ectoparasitic flagellate Ellobiopsis chattoni Caullery infecting the zoea of the crab were observed from off Cape Comorin, the south-east coast of India...

  9. The anatomy of the king crab Hapalogaster mertensii Brandt, 1850 (Anomura: Paguroidea: Hapalogastridae): new insights into the evolutionary transformation of hermit crabs into king crabs

    NARCIS (Netherlands)

    Keiler, J.; Richter, S.; Wirkner, C.S.

    2015-01-01

    The emergence of king crabs from a hermit crab-like ancestor is one of the most curious events in decapod evolution. King crabs comprise two taxa, Lithodidae and Hapalogastridae, and while lithodids have formed the focus of various anatomical studies, the internal anatomy of hapalogastrids has never

  10. Crabs

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.

    stream_size 2 stream_content_type text/plain stream_name Biodiversity_Western_Ghats_Inf_Kit_1994_3.6_1.pdf.txt stream_source_info Biodiversity_Western_Ghats_Inf_Kit_1994_3.6_1.pdf.txt Content-Encoding ISO-8859-1 Content-Type text...

  11. Epibiotic community of the horseshoe crab Tachypleus gigas

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Anil, A.C.

    -epibionts) present on horseshoe crabs, according to gender, were evaluated, and the macro-epibiont population from different regions of the carapace was mapped. In general, female horseshoe crabs harbored fewer epibionts than the males. Among the diatoms, Navicula...

  12. Statement on Bills to Designate Crab Orchard Wilderness

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Statement of John Kyl on H.R. 3508 and H.R. 5893, bills to designate Crab Orchard Wilderness within Crab Orchard National Wildlife Refuge. This document includes maps.

  13. Nucleotide sequences of two fimbrial major subunit genes, pmpA and ucaA, from canine-uropathogenic Proteus mirabilis strains.

    Science.gov (United States)

    Bijlsma, I G; van Dijk, L; Kusters, J G; Gaastra, W

    1995-06-01

    Proteus mirabilis strains were isolated from dogs with urinary tract infection (UTI) and fimbriae were prepared from two strains. The N-terminal amino acid sequences of the major fimbrial subunits were determined and both sequences appeared identical to the N-terminal amino acid sequence of a urinary cell adhesin (UCA) (Wray, S. K., Hull, S. I., Cook, R. G., Barrish, J. & Hull, R. A., 1986, Infect Immun 54, 43-49). The genes of two different major fimbrial subunits were cloned using oligonucleotide probes that were designed on the basis of the N-terminal UCA sequence. Nucleotide sequencing revealed the complete ucaA gene of 540 bp (from strain IVB247) encoding a polypeptide of 180 amino acids, including a 22 amino acid signal sequence peptide, and the pmpA (P. mirabilis P-like pili) gene of 549 bp (from strain IVB219) encoding a polypeptide of 183 amino acids, including a 23 amino acid signal sequence. Hybridization experiments gave clear indications of the presence of both kinds of fimbriae in many UTI-related canine P. mirabilis isolates. However, the presence of these fimbriae could not be demonstrated in P. vulgaris or other Proteus-related species. Database analysis of amino acid sequences of major subunit proteins revealed that the UcaA protein shares about 56% amino acid identity with the F17A and F111A major fimbrial subunits from bovine enterotoxigenic Escherichia coli. In turn, the PmpA protein more closely resembled the pyelonephritis-associated pili (Pap)-like major subunit protein from UTI-related E. coli. The evolutionary relationship of UcaA, PmpA and various other fimbrial subunit proteins is presented in a phylogenetic tree.

  14. The Radio Spectral Index of the Crab Nebula

    Science.gov (United States)

    1997-11-20

    We present the results of a new, comprehensive investigation of the radio spectral index of the Crab Nebula supernova remnant. New data at 74 MHz are...thermal material in the Crab Nebula’s filaments. Apart from some possible renewed acceleration occurring in the wisps, the dominant accelerator of relativistic electrons in the Crab Nebula is the pulsar itself.

  15. Black yeast-like fungi associated with Lethargic Crab Disease (LCD) in the mangrove-land crab, Ucides cordatus (Ocypodidae).

    NARCIS (Netherlands)

    Vicente, V.A.; Orelis-Ribeiro, R.; Najafzadeh, M.J.; Sun, J.; Guerra, R.S.; Miesch, S.; Ostrensky, A.; Meis, J.F.G.M.; Klaassen, C.H.; Hoog, G.S. de; Boeger, W.A.

    2012-01-01

    Lethargic Crab Disease (LCD) caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Brachyura: Ocypodidae) along the Brazilian coast, mainly in the Northeastern region. The disease was named after the symptoms of slow movement of infected crabs. Causative agents were suspect

  16. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang

    2010-05-23

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  17. Thermal specialization across large geographical scales predicts the resilience of mangrove crab populations to global warming

    KAUST Repository

    Fusi, Marco

    2014-11-18

    The broad prediction that ectotherms will be more vulnerable to climate change in the tropics than in temperate regions includes assumptions about centre/edge population effects that can only be tested by within-species comparisons across wide latitudinal gradients. Here, we investigated the thermal vulnerability of two mangrove crab species, comparing populations at the centre (Kenya) and edge (South Africa) of their distributions. At the same time, we investigated the role of respiratory mode (water- versus air-breathing) in determining the thermal tolerance in amphibious organisms. To do this, we compared the vulnerability to acute temperature fluctuations of two sympatric species with two different lifestyle adaptations: the free living Perisesarma guttatum and the burrowing Uca urvillei, both pivotal to the ecosystem functioning of mangroves. The results revealed the air-breathing U. urvillei to be a thermal generalist with much higher thermal tolerances than P. guttatum. Importantly, however, we found that, while U. urvillei showed little difference between edge and centre populations, P. guttatum showed adaptation to local conditions. Equatorial populations had elevated tolerances to acute heat stress and mechanisms of partial thermoregulation, which make them less vulnerable to global warming than temperate conspecifics. The results reveal both the importance of respiratory mode to thermal tolerance and the unexpected potential for low latitude populations/species to endure a warming climate. The results also contribute to a conceptual model on the latitudinal thermal tolerance of these key species. This highlights the need for an integrated population-level approach to predict the consequences of climate change. © 2014 The Authors.

  18. Frequency Tuning for a DQW Crab Cavity

    CERN Document Server

    Verdú-Andrés, Silvia; Ben-Zvi, Ilan; Calaga, Rama; Capatina, Ofelia; Leuxe, Raphael; Skaritka, John; Wu, Qiong; Xiao, Binping; Zanoni, Carlo

    2016-01-01

    The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

  19. Evolution of metabolomics profile of crab paste during fermentation.

    Science.gov (United States)

    Chen, Daian; Ye, Yangfang; Chen, Juanjuan; Yan, Xiaojun

    2016-02-01

    Crab paste is regularly consumed by people in the coastal area of China. The fermentation time plays a key role on the quality of crab paste. Here, we investigated the dynamic evolution of metabolite profile of crab paste during fermentation by combined use of NMR spectroscopy and multivariate data analysis. Our results showed that crab paste quality was significantly affected by fermentation. The quality change was manifested in the decline of lactate, betaine, taurine, trimethylamine-N-oxide, trigonelline, inosine, adenosine diphosphate, and 2-pyridinemethanol, and in the fluctuation of a range of amino acids as well as in the accumulation of glutamate, sucrose, formate, acetate, trimethylamine, and hypoxanthine. Trimethylamine production and its increased level with fermentation could be considered as a freshness index of crab paste. These results contribute to quality assessment of crab paste and confirm the metabolomics technique as a useful tool to provide important information on the crab paste quality.

  20. Modeling Crabbing Dynamics in an Electron-Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Castilla, Alejandro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Univ. de Guanajuato (DCI-UG), Leon (Mexico); Morozov, Vasiliy S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Satogata, Todd J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Delayen, Jean R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)

    2015-09-01

    A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.

  1. A Comparative Study of Genetic Variation betwccn Chinese Mitten Crab Eriocheir Sinensis and Hepu Mitten Crab E. Hepuensis

    Institute of Scientific and Technical Information of China (English)

    LIU Guangdong; ZHANG Xiumei; GAO Tianxiang; LOU Dong

    2002-01-01

    Horizontal starch gel electrophoresis was used to investigate the biochemical genetic structure of Chinese mittencrab Eriocheir sinensis and Hepu mitten crab E. hepuensis. Sixteen putative enzyme-coding loci were examined for forty-nineChinese mitten crabs and thirty-eight Hepu mitten crabs. Nine loci, AAT-1 *, AAT-2 *, G3PDH*, GPI*, IDHP-1 *, IDHP-2 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Chinese mitten crab, and seven, AAT-1 *, AAT-2 *, GPI *, IDHP-1 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Hepu mitten crab. The proportion of polymorphic loci and the expectedheterozygosity are 0.562 5 and 0.080 3 for Chinese mitten crab, and 0.437 5 and 0.075 4 for Hepu mitten crab. The Nei' s ge-netic distance between two species is 0.002 4.

  2. Formação de Professores que Ensinam Matemática no Contexto da Cibercultura: Estudo em uma Escola UCA

    Directory of Open Access Journals (Sweden)

    Dennys Leite Maia

    2014-09-01

    Full Text Available Nas últimas décadas, com o advento das tecnologias digitais, a sociedade tem passado por uma reconfiguração. As relações entre tais tecnologias e a cultura contemporânea é definida como Cibercultura. Nessa perspectiva, este trabalho tem como objetivo analisar de que forma as interações mediadas pelas tecnologias digitais contribuem para o desenvolvimento profissional do professor de Matemática, particularmente sobre o laptop educacional, do Projeto Um Computador por Aluno (UCA. Como método de pesquisa, utilizamos elementos da Pesquisa Colaborativa. A pesquisa foi realizada em uma escola de Ensino Fundamental, participante do Projeto UCA, localizada em Fortaleza-CE.

  3. Ocean acidification impairs crab foraging behaviour.

    Science.gov (United States)

    Dodd, Luke F; Grabowski, Jonathan H; Piehler, Michael F; Westfield, Isaac; Ries, Justin B

    2015-07-07

    Anthropogenic elevation of atmospheric CO2 is driving global-scale ocean acidification, which consequently influences calcification rates of many marine invertebrates and potentially alters their susceptibility to predation. Ocean acidification may also impair an organism's ability to process environmental and biological cues. These counteracting impacts make it challenging to predict how acidification will alter species interactions and community structure. To examine effects of acidification on consumptive and behavioural interactions between mud crabs (Panopeus herbstii) and oysters (Crassostrea virginica), oysters were reared with and without caged crabs for 71 days at three pCO2 levels. During subsequent predation trials, acidification reduced prey consumption, handling time and duration of unsuccessful predation attempt. These negative effects of ocean acidification on crab foraging behaviour more than offset any benefit to crabs resulting from a reduction in the net rate of oyster calcification. These findings reveal that efforts to evaluate how acidification will alter marine food webs should include quantifying impacts on both calcification rates and animal behaviour. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  4. Horseshoe crab behavior:Patterns and processes

    Institute of Scientific and Technical Information of China (English)

    Christopher C.Chabot; Winsor H.Watson Ⅲ

    2010-01-01

    @@ 1 Introduction The American horseshoe crab Limulus polyphemus has long served as a source of delight and inspiration to a broad cross-section of scientists - from naturalists to neuroscientists. Periodically, for the last hundred years or so, new discoveries have been made about this ancient creature that both enlighten scientists and reinforce the importance of conserving this ancient species.

  5. The tree-climbing crabs of Trinidad

    NARCIS (Netherlands)

    Hagen, von Heinrich-Otto

    1977-01-01

    An annotated list of the brachyuran (12) and anomuran (1) tree-climbing crabs of Trinidad (West Indies) is presented (see Table 1 for species names). Some of the species mentioned (e.g. Aratus pisonii, Goniopsis cruentata) are well-known treeclimbers, in others (e.g. Sesarma roberti, S. ricordi) thi

  6. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This picture shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally 'changes it stripes' every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  7. Corneal laceration caused by river crab

    Directory of Open Access Journals (Sweden)

    Vinuthinee N

    2015-01-01

    Full Text Available Naidu Vinuthinee,1,2 Anuar Azreen-Redzal,1 Jaafar Juanarita,1 Embong Zunaina2 1Department of Ophthalmology, Hospital Sultanah Bahiyah, Alor Setar, 2Department of Ophthalmology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia Abstract: A 5-year-old boy presented with right eye pain associated with tearing and photophobia of 1-day duration. He gave a history of playing with a river crab when suddenly the crab clamped his fingers. He attempted to fling the crab off, but the crab flew and hit his right eye. Ocular examination revealed a right eye corneal ulcer with clumps of fibrin located beneath the corneal ulcer and 1.6 mm level of hypopyon. At presentation, the Seidel test was negative, with a deep anterior chamber. Culture from the corneal scrapping specimen grew Citrobacter diversus and Proteus vulgaris, and the boy was treated with topical gentamicin and ceftazidime eyedrops. Fibrin clumps beneath the corneal ulcer subsequently dislodged, and revealed a full-thickness corneal laceration wound with a positive Seidel test and shallow anterior chamber. The patient underwent emergency corneal toileting and suturing. Postoperatively, he was treated with oral ciprofloxacin 250 mg 12-hourly for 1 week, topical gentamicin, ceftazidime, and dexamethasone eyedrops for 4 weeks. Right eye vision improved to 6/9 and 6/6 with pinhole at the 2-week follow-up following corneal suture removal. Keywords: corneal ulcer, pediatric trauma, ocular injury

  8. Swimming of the pea crab (Pinnotheres pisum)

    NARCIS (Netherlands)

    Versteegh, C.P.C.; Muller, M.

    2014-01-01

    Aquatic organisms have to deal with different hydrodynamic regimes, depending on their size and speed during locomotion. The pea crab swims by beating the third and fourth pereiopod on opposite sides as pairs. Using particle tracking velocimetry and high-speed video recording, we quantify the kinema

  9. Power coupler for the ILC crab cavity

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; Jenkins, R.; /Lancaster U.; Beard, C.; Goudket, P.; McIntosh, P.A.; /Daresbury; Bellantoni, Leo; /Fermilab

    2007-06-01

    The ILC crab cavity will require the design of an appropriate power coupler. The beam-loading in dipole mode cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Simulations of a suitable coupler were then performed and were verified using a normal conducting prototype with variable coupler tips.

  10. The CMS Remote Analysis Builder (CRAB)

    Energy Technology Data Exchange (ETDEWEB)

    Spiga, D.; Cinquilli, M.; Servoli, L.; /INFN, Perugia /Perugia U; Lacaprara, S.; Fanzago, F.; Dorigo, A.; /INFN, Padova; Merlo, M.; Farina, F.; /INFN, Milan /Milan U; Fanfani, A.; Codispoti, G.; Bacchi, W.; /INFN, Bologna /Bologna U /CERN /INFN, CNAF /INFN, Trieste /Fermilab

    2008-01-22

    The CMS experiment will produce several Pbytes of data every year, to be distributed over many computing centers geographically distributed in different countries. Analysis of this data will be also performed in a distributed way, using grid infrastructure. CRAB (CMS Remote Analysis Builder) is a specific tool, designed and developed by the CMS collaboration, that allows a transparent access to distributed data to end physicist. Very limited knowledge of underlying technicalities are required to the user. CRAB interacts with the local user environment, the CMS Data Management services and with the Grid middleware. It is able to use WLCG, gLite and OSG middleware. CRAB has been in production and in routine use by end-users since Spring 2004. It has been extensively used in studies to prepare the Physics Technical Design Report (PTDR) and in the analysis of reconstructed event samples generated during the Computing Software and Analysis Challenge (CSA06). This involved generating thousands of jobs per day at peak rates. In this paper we discuss the current implementation of CRAB, the experience with using it in production and the plans to improve it in the immediate future.

  11. Dominance and population structure of freshwater crabs ...

    African Journals Online (AJOL)

    1997-02-06

    Feb 6, 1997 ... systems and fonm a major part of the diet of many vertebrates, little is known about their biology. ... dominant or even keystone species (Power, Tilman, Estes, .... crabs were fed ad lih with Lopis® rabbit pellets every day.

  12. Calcification and growth processes in planktonic foraminifera complicate the use of B/Ca and U/Ca as carbonate chemistry proxies

    Science.gov (United States)

    Salmon, Kate H.; Anand, Pallavi; Sexton, Philip F.; Conte, Maureen

    2016-09-01

    Although boron and uranium to calcium ratios (B/Ca, U/Ca) in planktonic foraminifera have recently received much attention as potential proxies for ocean carbonate chemistry, the extent of a carbonate chemistry control on these ratios remains contentious. Here, we use bi-weekly sediment trap samples collected from the subtropical North Atlantic in combination with measured oceanographic data from the same location to evaluate the dominant oceanographic controls on B/Ca and U/Ca in three depth-stratified species of planktonic foraminifera. We also test the control of biological, growth-related, processes on planktonic foraminiferal B and U incorporation by using foraminifer test area density (μ g /μm2) (a monitor of test thickness) and test size from the same samples. B/Ca and U/Ca show little or no significant correlation with carbonate system parameters both within this study and in comparison with other published works. We provide the first evidence for a strong positive relationship between area density (test thickness) and B/Ca, and reveal that this is consistent in all species studied, suggesting a likely role for calcification in controlling boron partitioning into foraminiferal calcite. This finding is consistent with previous observations of less efficient discrimination against trace element 'impurities' (such as B), at higher calcification rates. We observe little or no dependency of B/Ca on test size. In marked contrast, we find that U/Ca displays a strong species-specific dependency on test size in all species, but no relationship with test thickness, implicating some other biological control (possibly related to growth), rather than a calcification control, on U incorporation into foraminiferal calcite. Our results caution against the use of B/Ca and U/Ca in planktonic foraminifera as reliable proxies for the ocean carbonate system and recommend that future work should concentrate on improving the mechanistic understanding of how planktonic

  13. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Brown Rock Crab, Red Rock Crab, and Yellow Crab

    Science.gov (United States)

    1989-12-01

    distinguished by a slender abdomen and Two other large Cancer species, the Dungeness crab mature females by a broad abdomen that is often hirsute (C. magister...to the scent experimental treatment . One 13th instar female crab of potential food in the water (Case 1964; Zimmer-Faust reared at 22 ’C became

  14. Accumulation and depuration of pectenotoxins in brown crab Cancer pagurus

    Institute of Scientific and Technical Information of China (English)

    LI Zhaoxin

    2009-01-01

    Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus edulis for 21 days and then depurated for 42 days. Toxins were extracted with methanol from the digestive glands of contaminated crabs, uncontaminated crabs (control group) and from blue mussels for comparison. Extracts were analyzed by liquid chromatograph coupled with tandem mass spectrometry (LC-MS-MS). The concentrations of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, and PTX-12 were analyzed in two batches of toxic blue mussels and the crabs. A one-compartment model was applied to describe the depuration of PTXs. The half-life of PTXs was estimated to be 6-7.5 days. After depuration for 42 days, the amount of PTXs measured in the crab digestive glands was less than 1 μg/kg.

  15. Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

    Directory of Open Access Journals (Sweden)

    Avery E. Scherer

    2017-02-01

    Full Text Available By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging.

  16. A 150-million-year-old crab larva and its implications for the early rise of brachyuran crabs.

    Science.gov (United States)

    Haug, Joachim T; Martin, Joel W; Haug, Carolin

    2015-03-09

    True crabs (Brachyura) are the most successful group of decapod crustaceans. This success is most likely coupled to their life history, including two specialised larval forms, zoea and megalopa. The group is comparably young, starting to diversify only about 100 million years ago (mya), with a dramatic increase in species richness beginning approximately 50 mya. Early evolution of crabs is still very incompletely known. Here, we report a fossil crab larva, 150 mya, documented with up-to-date imaging techniques. It is only the second find of any fossil crab larva, but the first complete one, the first megalopa, and the oldest one (other fossil ca. 110 mya). Despite its age, the new fossil possesses a very modern morphology, being indistinguishable from many extant crab larvae. Hence, modern morphologies must have been present significantly earlier than formerly anticipated. We briefly discuss the impact of this find on our understanding of early crab evolution.

  17. Bacterial septicaemia in prerecruit edible crabs, Cancer pagurus L.

    Science.gov (United States)

    Smith, A L; Whitten, M M A; Hirschle, L; Pope, E C; Wootton, E C; Vogan, C L; Rowley, A F

    2014-08-01

    Juvenile edible crabs, Cancer pagurus L., were surveyed from Mumbles Head and Oxwich Bay in South Wales, UK, and the number of heterotrophic bacteria and vibrios in the hemolymph was determined. The percentage of crabs with hemolymph containing bacteria was variable over the survey with higher numbers of animals affected in summer than in winter. Post-moult crabs contained significantly higher numbers of heterotrophic bacteria in the hemolymph than pre- and intermoult animals. Crabs with cuticular damage to the gills also had significantly higher numbers of bacteria in the hemolymph. Crabs were found to have a high prevalence of infection by the dinoflagellate, Hematodinium. Such animals had significantly fewer bacteria in the blood in comparison with Hematodinium-free animals. Of the 463 crabs surveyed, only 3 individuals had hemolymph containing 2000 + CFU mL(-1). Based on 16S rRNA gene sequences, two of these crabs contained a Vibrio pectenicida-like isolate, while the other had a mixed assemblage of vibrios. Although 59% of the crabs surveyed had culturable bacteria in the hemolymph, the majority only had small numbers (crab fishery in this region.

  18. FACT. Energy spectrum of the Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

    2016-07-01

    The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

  19. Pulse profile stability of the Crab pulsar

    CERN Document Server

    Jain, Chetana

    2011-01-01

    We present an X-ray timing analysis of the Crab pulsar, PSR B0531+21, using the archival RXTE data. We have investigated the stability of the Crab pulse profile, in soft (2-20 keV) and hard (30-100 keV) X-ray energies, over the last decade of RXTE operation. The analysis includes measurement of the separation between the two pulse peaks; and intensity and the widths of the two peaks. We did not find any significant time dependency in the pulse shape. The two peaks are stable in phase, intensity and widths, for the last ten years. The first pulse is relatively stronger at soft X-rays. The first pulse peak is narrower than the second peak, in both, soft- and hard X-ray energies. Both the peaks show a slow rise and a steeper fall. The ratio of the pulsed photons in the two peaks is also constant in time.

  20. Multiband observations of the Crab Nebula

    Science.gov (United States)

    Krassilchtchikov, A. M.; Bykov, A. M.; Castelletti, G. M.; Dubner, G. M.; Kargaltsev, O. Yu; Pavlov, G. G.

    2017-01-01

    Results of simultaneous imaging of the Crab Nebula in the radio (JVLA), optical (HST), and X-ray (Chandra) bands are presented. The images show a variety of small-scale structures, including wisps mainly located to the north-west of the pulsar and knots forming a ring-like structure associated with the termination shock of the pulsar wind. The locations of the structures in different bands do not coincide with each other.

  1. Pulsating Radio Sources near the Crab Nebula.

    Science.gov (United States)

    Staelin, D H; Reifenstein, E C

    1968-12-27

    Two new pulsating radio sources, designated NP 0527 and NP 0532, were found near the Crab Nebula and could be coincident with it. Both sources are sporadic, and no periodicities are evident. The pulse dispersions indicate that 1.58 +/- 0.03 and 1.74 +/- 0.02 x 10(20) electrons per square centimeter lie in the direction of NP 0527 and NP 0532, respectively.

  2. THE OSMOREGULATORY ABILITY OF THREE GRAPSOID CRAB ...

    African Journals Online (AJOL)

    ... of the araPIOicl crabs Cyc1oaraJn1ll 1I1111&1atlll, Satunul CIlIMIIIiI aDd .... The experimental media used were sea-water of salinity 34%" volumetrically diluted with ... The freezing point of the haemolymph collected from the arthrodial ... marked increase in mortality at salinities below 10%0. and experiments were not ...

  3. A Large Glitch in the Crab Pulsar

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using a new pulsar timing system at the 25-m radio telescope of Urumqi Astronomical Observatory, we have detected a large glitch in the Crab pulsar which occurred in 2000 July. The size of the gfitch is Av/v ~ 2.4 × 10-8, with a rela tive increment in frequency derivative Av/v ~ 5 × 10-3. The observing system is introduced and the observed properties of the glitch are discussed.

  4. The inner knot of the Crab nebula

    Science.gov (United States)

    Lyutikov, Maxim; Komissarov, Serguei S.; Porth, Oliver

    2016-02-01

    We model the inner knot of the Crab nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, σ ≤ 1. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar ≥45°; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this is an unlikely site for the Crab's gamma-ray flares, if they are related to the fast relativistic magnetic reconnection events.

  5. The Porcelain Crab Transcriptome and PCAD, the Porcelain Crab Microarray and Sequence Database

    Energy Technology Data Exchange (ETDEWEB)

    Tagmount, Abderrahmane; Wang, Mei; Lindquist, Erika; Tanaka, Yoshihiro; Teranishi, Kristen S.; Sunagawa, Shinichi; Wong, Mike; Stillman, Jonathon H.

    2010-01-27

    Background: With the emergence of a completed genome sequence of the freshwater crustacean Daphnia pulex, construction of genomic-scale sequence databases for additional crustacean sequences are important for comparative genomics and annotation. Porcelain crabs, genus Petrolisthes, have been powerful crustacean models for environmental and evolutionary physiology with respect to thermal adaptation and understanding responses of marine organisms to climate change. Here, we present a large-scale EST sequencing and cDNA microarray database project for the porcelain crab Petrolisthes cinctipes. Methodology/Principal Findings: A set of ~;;30K unique sequences (UniSeqs) representing ~;;19K clusters were generated from ~;;98K high quality ESTs from a set of tissue specific non-normalized and mixed-tissue normalized cDNA libraries from the porcelain crab Petrolisthes cinctipes. Homology for each UniSeq was assessed using BLAST, InterProScan, GO and KEGG database searches. Approximately 66percent of the UniSeqs had homology in at least one of the databases. All EST and UniSeq sequences along with annotation results and coordinated cDNA microarray datasets have been made publicly accessible at the Porcelain Crab Array Database (PCAD), a feature-enriched version of the Stanford and Longhorn Array Databases.Conclusions/Significance: The EST project presented here represents the third largest sequencing effort for any crustacean, and the largest effort for any crab species. Our assembly and clustering results suggest that our porcelain crab EST data set is equally diverse to the much larger EST set generated in the Daphnia pulex genome sequencing project, and thus will be an important resource to the Daphnia research community. Our homology results support the pancrustacea hypothesis and suggest that Malacostraca may be ancestral to Branchiopoda and Hexapoda. Our results also suggest that our cDNA microarrays cover as much of the transcriptome as can reasonably be captured in

  6. Comparative analysis of the proximate and elemental composition of the blue crab Callinectes sapidus, the warty crab Eriphia verrucosa, and the edible crab Cancer pagurus

    Directory of Open Access Journals (Sweden)

    Maurizio Zotti

    2016-02-01

    Full Text Available The proximate composition and element contents of claw muscle tissue of Atlantic blue crabs (Callinectes sapidus were compared with the native warty crab (Eriphia verrucosa and the commercially edible crab (Cancer pagurus. The scope of the analysis was to profile the chemical characteristics and nutritive value of the three crab species. Elemental fingerprints showed significant inter-specific differences, whereas non-significant variations in the moisture and ash contents were observed. In the blue crab, protein content was significantly lower than in the other two species, while its carbon content resulted lower than that characterizing only the warty crab. Among micro-elements, Ba, Cr, Cu, Li, Mn, Ni, and Pb showed extremely low concentrations and negligible among-species differences. Significant inter-specific differences were observed for Na, Sr, V, Ba, Cd and Zn; in particular, cadmium and zinc were characterized in the blue crab by concentrations significantly lower than in the other two species. The analysis of the available literature on the three species indicated a general lack of comparable information on their elemental composition. The need to implement extended elemental fingerprinting techniques for shellfish quality assessment is discussed, in view of other complementary profiling methods such as NMR-based metabolomics.

  7. Comparative analysis of the proximate and elemental composition of the blue crab Callinectes sapidus, the warty crab Eriphia verrucosa, and the edible crab Cancer pagurus.

    Science.gov (United States)

    Zotti, Maurizio; Coco, Laura Del; Pascali, Sandra Angelica De; Migoni, Danilo; Vizzini, Salvatrice; Mancinelli, Giorgio; Fanizzi, Francesco Paolo

    2016-02-01

    The proximate composition and element contents of claw muscle tissue of Atlantic blue crabs (Callinectes sapidus) were compared with the native warty crab (Eriphia verrucosa) and the commercially edible crab (Cancer pagurus). The scope of the analysis was to profile the chemical characteristics and nutritive value of the three crab species. Elemental fingerprints showed significant inter-specific differences, whereas non-significant variations in the moisture and ash contents were observed. In the blue crab, protein content was significantly lower than in the other two species, while its carbon content resulted lower than that characterizing only the warty crab. Among micro-elements, Ba, Cr, Cu, Li, Mn, Ni, and Pb showed extremely low concentrations and negligible among-species differences. Significant inter-specific differences were observed for Na, Sr, V, Ba, Cd and Zn; in particular, cadmium and zinc were characterized in the blue crab by concentrations significantly lower than in the other two species. The analysis of the available literature on the three species indicated a general lack of comparable information on their elemental composition. The need to implement extended elemental fingerprinting techniques for shellfish quality assessment is discussed, in view of other complementary profiling methods such as NMR-based metabolomics.

  8. Seawater nutrient and carbonate ion concentrations recorded as P/Ca, Ba/Ca, and U/Ca in the deep-sea coral Desmophyllum dianthus

    Science.gov (United States)

    Anagnostou, Eleni; Sherrell, Robert M.; Gagnon, Alex; LaVigne, Michele; Field, M. Paul; McDonough, William F.

    2011-05-01

    As paleoceanographic archives, deep sea coral skeletons offer the potential for high temporal resolution and precise absolute dating, but have not been fully investigated for geochemical reconstructions of past ocean conditions. Here we assess the utility of skeletal P/Ca, Ba/Ca and U/Ca in the deep sea coral D. dianthus as proxies of dissolved phosphate (remineralized at shallow depths), dissolved barium (trace element with silicate-type distribution) and carbonate ion concentrations, respectively. Measurements of these proxies in globally distributed D. dianthus specimens show clear dependence on corresponding seawater properties. Linear regression fits of mean coral Element/Ca ratios against seawater properties yield the equations: P/Ca coral (μmol/mol) = (0.6 ± 0.1) P/Ca sw(μmol/mol) - (23 ± 18), R2 = 0.6, n = 16 and Ba/Ca coral(μmol/mol) = (1.4 ± 0.3) Ba/Ca sw(μmol/mol) + (0 ± 2), R2 = 0.6, n = 17; no significant relationship is observed between the residuals of each regression and seawater temperature, salinity, pressure, pH or carbonate ion concentrations, suggesting that these variables were not significant secondary dependencies of these proxies. Four D. dianthus specimens growing at locations with Ωarag ⩽ 0.6 displayed markedly depleted P/Ca compared to the regression based on the remaining samples, a behavior attributed to an undersaturation effect. These corals were excluded from the calibration. Coral U/Ca correlates with seawater carbonate ion: U/Ca coral(μmol/mol) = (-0.016 ± 0.003) [CO32-] (μmol/kg) + (3.2 ± 0.3), R2 = 0.6, n = 17. The residuals of the U/Ca calibration are not significantly related to temperature, salinity, or pressure. Scatter about the linear calibration lines is attributed to imperfect spatial-temporal matches between the selected globally distributed specimens and available water column chemical data, and potentially to unresolved additional effects. The uncertainties of these initial proxy calibration regressions

  9. Enhanced gamma-ray activity from the Crab nebula

    Science.gov (United States)

    Buehler, R.; Ciprini, S.

    2016-01-01

    Preliminary LAT analysis indicates enhanced gamma-ray activity from the Crab nebula. The daily-averaged gamma-ray emission (E > 100 MeV) from the direction of the Crab Nebula has surpassed 4.0 x 10^-6 ph cm^-2 s^-1 five times in the last 12 days.

  10. Brachyuran Crabs collected at Curaçao

    NARCIS (Netherlands)

    Rathbun, Mary J.

    1924-01-01

    In 1920 a report ¹) on Dr. BOEKE’S collection of crabs and shrimps from Curaçao and other Dutch West Indian Islands was published. Dr. VAN DER HORST’S collection forms an important addition to the fauna of Curaçao, especially as to the Xanthids and Majids, or spider crabs. Four new species were disc

  11. Crab biodiversity under different management schemes of mangrove ecosystems

    Directory of Open Access Journals (Sweden)

    M. Bandibas

    2016-01-01

    Full Text Available Reforestation is one of the Philippines’ government efforts to restore and rehabilitate degraded mangrove ecosystems. Although there is recovery of the ecosystem in terms of vegetation, the recovery of closely-linked faunal species in terms of community structure is still understudied. This research investigates the community structure of mangrove crabs under two different management schemes: protected mangroves and reforested mangroves. The transect-plot method was employed in each management scheme to quantify the vegetation, crab assemblages and environmental variables. Community composition of crabs and mangrove trees were compared between protected and reforested mangroves using non-metric multi-dimensional scaling and analysis of similarity in PRIMER 6. Chi-squared was used to test the variance of sex ration of the crabs. Canonical Correspondence Analysis was used to determine the relationship between crabs and environmental parameters. A total of twelve species of crabs belonging to six families were identified in protected mangroves while only four species were documented in reforested mangroves. Perisesarma indiarum and Baptozius vinosus were the most dominant species in protected and reforested mangrove, respectively.  Univariate analysis of variance of crab assemblage data revealed significant differences in crab composition and abundance between protected mangroves and from reforested mangroves (P

  12. Characteristics of cobalt removal by crab shell particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, MooYeal; Kajiuchi, Toshio [Department of International Development, Tokyi Institute of Technology, Tokyo (Korea, Republic of); Kang, Hyun Ah; Yang, Ji Won [Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-07-01

    The characteristics of cobalt removal by raw crab shell particles was investigated. The removal efficiency of cobalt was dependent on contact time, solution pH, crab shell dose and ionic strength. Approximately 99% of the cobalt was removed within 6 hour after contact with crab shell particles. The removal efficiency was slightly affected by initial solution pH over 5.0 and the final solution pH changed to 10 spontaneously. In addition, optimum pH range of cobalt removal was broaden by the effect of crab shell addition. Maximum uptake of cobalt was 510 mg Co/g crab shell at initial pH 5.0. The removal efficiency was affected slightly by ionic strength up to 2.0 M of NaCl. From the results of scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), the removal of cobalt by crab shell was mainly through the dissolution of CaCO{sub 3} followed by precipitation of Co(OH){sub 2} and CoCO{sub 3} and then the precipitates were adsorbed to the chitin on the surface of crab shell particles. Compared to the results with activated carbon column, the addition of crab shell to activated carbon column increased the removal efficiency dramatically.(author)

  13. Crabbed Waist Collisions in DAFNE and Super-B Design

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Alesini, D.; Biagini, M.E.; Biscari, C.; Boni, R.; Boscolo, M.; Bossi, F.; Buonomo, B.; Clozza, A.; Delle Monache, G.O.; Demma, T.; Di Pasquale, E.; Di Pirro, G.; Drago, A.; Gallo, A.; Ghigo, A.; Guiducci, S.; Ligi, C.; Marcellini, F.; Mazzitelli, Giovanni; Milardi, C.; /Frascati /Orsay, LAL /CERN /Rome III U. /Rome U. /Novosibirsk, IYF /KEK, Tsukuba /INFN, Pisa /INFN, Cosenza /SLAC /Frascati

    2011-11-02

    The new idea of increasing the luminosity of a collider with crab waist collisions and first experimental results from the DA{Phi}NE {Phi}-Factory at LNF, Frascati, using this concept are presented. Consequences for the design of future factories will be discussed. An outlook to the performance reach with crab waist collisions is given, with emphasis on future B Factories.

  14. Evolutionary diversification of coral-dwelling gall crabs (Cryptochiridae)

    NARCIS (Netherlands)

    Meij, Sancia Esmeralda Theonilla van der

    2015-01-01

    Gall crabs (Crustacea : Cryptochiridae) are small, coral-dwelling crabs that live in obligate association with their host corals (Scleractinia), on which they rely for food and shelter. They have been recorded from shallow and deeper waters (over 500 m), but the majority of the species live in reef

  15. 50 CFR Table 2 to Part 680 - Crab Species Code

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab Species Code 2 Table 2 to Part 680 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION..., Table 2 Table 2 to Part 680—Crab Species Code Species code Common name Scientific name 900...

  16. The Rhizocephalan parasite of the crab Xantho incisus (Leach)

    NARCIS (Netherlands)

    Boschma, H.

    1955-01-01

    As shown by Holthuis (1954), the correct name for the European crab commonly referred to as Xantho floridus (Montagu) is Xantho incisus (Leach). A Rhizocephalan parasite of this crab was first mentioned (without an indication of specific characters) by Gerbe (1862); afterwards specimens were recorde

  17. Land crabs as key drivers in tropical coastal forest recruitment

    Science.gov (United States)

    Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J.

    2009-01-01

    Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

  18. Small Angle Crab Compensation for LHC IR Upgrade

    CERN Document Server

    Akai, K; Dorda, U; Ohmi, K; Oide, K; Tomás, R; Zimmermann, T

    2007-01-01

    A small angle crab scheme is being considered for the LHC luminosity upgrade. In this paper we present a 400MHz superconducting cavity design and discuss the pertinent RF challenges. We also present a study on the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, with RF noise sources.

  19. Mitigating by-catch of diamondback terrapins in crab pots

    Science.gov (United States)

    Hart, Kristen M.; Crowder, Larry B.

    2011-01-01

    Chronic by-catch of diamondback terrapins (Malaclemys terrapin) in blue crab (Callinectes sapidus) pots is a concern for terrapin conservation along the United States Atlantic and Gulf of Mexico coasts. Despite the availability of by-catch reduction devices (BRDs) for crab pots, adoption of BRDs has not been mandated and by-catch of terrapins continues. We conducted experimental fishing studies in North Carolina's year-round blue crab fishery from 2000 to 2004 to evaluate the ability of various BRDs to reduce terrapin by-catch without a concomitant reduction in the catch of blue crabs. In 4,822 crab pot days fished, we recorded only 21 terrapin captures. Estimated capture rates were 0.003 terrapins/pot per day in hard crab experimental fishing and 0.008 terrapins/pot per day in peeler experimental fishing. All terrapin captures occurred from April to mid-May within 321.4 m of the shoreline. Longer soak times produced more dead terrapins, with 4 live and 4 dead during hard crab experimental fishing and 11 live and 2 dead during peeler experimental fishing. The 4.0-cm BRDs in fall and 4.5-cm and 5.0-cm BRDs in spring reduced the catch of legal-sized male hard crabs by 26.6%, 21.2%, and 5.7%, respectively. Only the 5.0-cm BRDs did not significantly affect the catch of legal-sized hard male crabs. However, BRDs had no measurable effect on catch of target crabs in the peeler crab fishery. Our results identify 3 complementary and economically feasible tools for blue crab fishery managers to exclude terrapins from commercially fished crab pots in North Carolina: 1) gear modifications (e.g., BRDs); 2) distance-to-shore restrictions; and 3) time-of-year regulations. These measures combined could provide a reduction in terrapin by-catch of up to 95% without a significant reduction in target crab catch.

  20. Rapid evolution to terrestrial life in Jamaican crabs

    Science.gov (United States)

    Schubart, Christoph D.; Diesel, Rudolf; Hedges, S. Blair

    1998-05-01

    Crabs of the family Grapsidae are abundant organisms in most intertidal communities. However, relatively few species live in complete independence of the sea. Of those species that do, Jamaica's nine endemic species of land crabs are unique in their exceptional adaptations to terrestrial life, which include the only active brood-care for larvae and juveniles known in crabs. These adaptations, and the morphological similarity to a group of southeast Asian land-dwelling crabs, have raised the question of the number and age of land invasions of the Jamaican species. Here we present molecular evidence that Jamaican land crabs represent a single adaptive radiation from a marine ancestor that invaded terrestrial habitats only 4 million years (Myr) ago. A Late-Tertiary origin has also been found for lizards and frogs of Jamaica and probably reflects the Mid-Tertiary inundation of that island.

  1. Crabs in Labs: The Shore Crab (Carcinus maenas) as Teaching Material.

    Science.gov (United States)

    Hogarth, P. J.

    1983-01-01

    The shore crab (Carcinus maenas) is an excellent subject for school study, both in the field and the laboratory. It is easily collected and maintained and can be used for a wide range of investigations. Some background details are given and possible areas of investigation suggested. (Author)

  2. 75 FR 32360 - Proposed Information Collection; Comment Request; Alaska Crab Report Forms

    Science.gov (United States)

    2010-06-08

    ... Crab Report Forms AGENCY: National Oceanic and Atmospheric Administration (NOAA), Department of.... 1801 et seq.) The FMP for Bering Sea and Aleutian Islands (BSAI) Crab includes the Crab Rationalization (CR) Program, a limited access system that allocates BSAI Management Area Crab resources...

  3. Death rate due to horseshoe crab poisoning:summarization on Thai reports

    Institute of Scientific and Technical Information of China (English)

    Beuy Joob; Viroj Wiwanitkit

    2015-01-01

    Horseshoe crab can be poisonous and intoxication due to intake of horseshoe crab is possible. Horseshoe crab intoxication can be seen in many countries with seacoasts including Thailand. Here, the authors summarized the death rate due to horseshoe crab poisoning in Thailand.

  4. LHC Crab Cavity Coupler Test Boxes

    CERN Document Server

    Mitchell, James; Burt, Graeme; Calaga, Rama; Macpherson, Alick; Montesinos, Eric; Silva, Subashini; Tutte, Adam; Xiao, Binping

    2016-01-01

    The LHC double quarter wave (DQW) crab cavities have two different types of Higher Order Mode (HOM) couplers in addition to a fundamental power coupler (FPC). The FPC requires conditioning, so to achieve this we have designed a radio-frequency (RF) quarter wave resonator to provide high transmission between two opposing FPCs. For the HOM couplers we must ensure that the stop-band filter is positioned at the cavity frequency and that peak transmission occurs at the same frequencies as the strongest HOMs. We have designed two test boxes which preserve the cavity spectral response in order to test the couplers.

  5. Element Masses in the Crab Nebula

    Science.gov (United States)

    Sibley, Adam R.; Katz, Andrea M.; Satterfield, Timothy J.; Vanderveer, Steven J.; MacAlpine, Gordon M.

    2016-10-01

    Using our previously published element abundance or mass-fraction distributions in the Crab Nebula, we derived actual mass distributions and estimates for overall nebular masses of hydrogen, helium, carbon, nitrogen, oxygen and sulfur. As with the previous work, computations were carried out for photoionization models involving constant hydrogen density and also constant nuclear density. In addition, employing new flux measurements for [Ni ii] λ7378, along with combined photoionization models and analytic computations, a nickel abundance distribution was mapped and a nebular stable nickel mass estimate was derived.

  6. Identification of irradiated crab using EPR

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, A. [Radiation Dosimetry Department, National Institute for Standards (NIS), Ministry of Scientific Research, Haram, 12211- Giza, P.O. Box: 136 (Egypt)]. E-mail: maghrabism@yahoo.com

    2007-02-15

    EPR spectroscopy is a fast and powerful technique for the identification of irradiated food. Crab exoskeleton was divided into six parts: dactyl, cheliped, carapace, apron, swimming legs, and walking legs. Samples of the exoskeleton were prepared and irradiated to Cs-137 gamma radiation in the range (1.156-5.365 kGy). EPR spectra of unirradiated as well as irradiated samples were recorded and analyzed. Response to gamma radiation was plotted for each part of the exoskeleton, dactyl was found to be the most sensitive part, followed by the apron (38%), cheliped (37%), walking legs (30%), swimming legs (24%), and carapace (21%) relative to the dactyl response.

  7. Habitat Suitability Index Models: Red king crab

    Science.gov (United States)

    Jewett, Stephen C.; Onuf, Christopher P.

    1988-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating habitat of different life stages of red king crab (Paralithodes camtschatica). A model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat) in Alaskan coastal waters, especially in the Gulf of Alaska and the southeastern Bering Sea. HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  8. Luminosity and Crab Waist Collision Studies

    CERN Document Server

    Wu, Wanwei

    2015-01-01

    In high energy physics, the luminosity is one useful value to characterize the performance of a particle collider. To gain more available data, we need to maximize the luminosity in most collider experiments. With the discussions of tune shift involved the beam dynamics and a recently proposed "crabbed waist" scheme of beam-beam collisions, we present some qualitative analysis to increase the luminosity. In addition, beam-beam tune shifts and luminosities of $e^{+}e^{-}$, $pp$/$p\\bar{p}$, and $\\mu^{+}\\mu^{-}$ colliders are discussed.

  9. Testing coral paleothermometers (B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O) under impacts of large riverine runoff

    Institute of Scientific and Technical Information of China (English)

    CHEN Tianran; YU Kefu; ZHAO Jianxin; YAN Hongqiang; SONG Yinxian; FENG Yuexing; CHEN Tegu

    2015-01-01

    Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O were analyzed in the skeleton of aPorites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral Sr/Ca shows the highest correlation with SST variations (r2=0.59), suggesting Sr/Ca is the most robust SST proxy. In contrast, coralδ18O (r2=0.46), B/Ca (r2=0.43) and U/Ca (r2=0.41) ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation (r2=0.27) between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.

  10. DARPA/USAF/USN J-UCAS X-45A System Demonstration Program: A Review of Flight Test Site Processes and Personnel

    Science.gov (United States)

    Cosentino, Gary B.

    2008-01-01

    The Joint Unmanned Combat Air Systems (J-UCAS) program is a collaborative effort between the Defense Advanced Research Project Agency (DARPA), the US Air Force (USAF) and the US Navy (USN). Together they have reviewed X-45A flight test site processes and personnel as part of a system demonstration program for the UCAV-ATD Flight Test Program. The goal was to provide a disciplined controlled process for system integration and testing and demonstration flight tests. NASA's Dryden Flight Research Center (DFRC) acted as the project manager during this effort and was tasked with the responsibilities of range and ground safety, the provision of flight test support and infrastructure and the monitoring of technical and engineering tasks. DFRC also contributed their engineering knowledge through their contributions in the areas of autonomous ground taxi control development, structural dynamics testing and analysis and the provision of other flight test support including telemetry data, tracking radars, and communications and control support equipment. The Air Force Flight Test Center acted at the Deputy Project Manager in this effort and was responsible for the provision of system safety support and airfield management and air traffic control services, among other supporting roles. The T-33 served as a J-UCAS surrogate aircraft and demonstrated flight characteristics similar to that of the the X-45A. The surrogate served as a significant risk reduction resource providing mission planning verification, range safety mission assessment and team training, among other contributions.

  11. Crab death assemblages from Laguna Madre and vicinity, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Plotnick, R.E.; McCarroll, S. (Univ. of Illinois, Chicago (USA)); Powell, E. (Texas A M Univ., College Station (USA))

    1990-02-01

    Crabs are a major component of modern marine ecosystems, but are only rarely described in fossil assemblages. Studies of brachyuran taphonomy have examined either the fossil end-products of the taphonomic process or the very earliest stages of decay and decomposition. The next logical step is the analysis of modern crab death assemblages; i.e., studies that examine taphonomic loss in areas where the composition of the living assemblage is known. The authors studied crab death assemblages in shallow water sediments at several localities in an near Laguna Madre, Texas. Nearly every sample examined contained some crab remains, most commonly in the form of isolated claws (dactyl and propodus). A crab fauna associated with a buried grass bed contained abundant remains of the xanthid crab Dyspanopeus texanus, including carapaces, chelipeds, and thoraxes, as well as fragments of the portunid Callinectes sapidus and the majiid Libinia dubia. Crab remains may be an overlooked portion of many preserved benthic assemblages, both in recent and modern sediments.

  12. The porcelain crab transcriptome and PCAD, the porcelain crab microarray and sequence database.

    Directory of Open Access Journals (Sweden)

    Abderrahmane Tagmount

    Full Text Available BACKGROUND: With the emergence of a completed genome sequence of the freshwater crustacean Daphnia pulex, construction of genomic-scale sequence databases for additional crustacean sequences are important for comparative genomics and annotation. Porcelain crabs, genus Petrolisthes, have been powerful crustacean models for environmental and evolutionary physiology with respect to thermal adaptation and understanding responses of marine organisms to climate change. Here, we present a large-scale EST sequencing and cDNA microarray database project for the porcelain crab Petrolisthes cinctipes. METHODOLOGY/PRINCIPAL FINDINGS: A set of approximately 30K unique sequences (UniSeqs representing approximately 19K clusters were generated from approximately 98K high quality ESTs from a set of tissue specific non-normalized and mixed-tissue normalized cDNA libraries from the porcelain crab Petrolisthes cinctipes. Homology for each UniSeq was assessed using BLAST, InterProScan, GO and KEGG database searches. Approximately 66% of the UniSeqs had homology in at least one of the databases. All EST and UniSeq sequences along with annotation results and coordinated cDNA microarray datasets have been made publicly accessible at the Porcelain Crab Array Database (PCAD, a feature-enriched version of the Stanford and Longhorn Array Databases. CONCLUSIONS/SIGNIFICANCE: The EST project presented here represents the third largest sequencing effort for any crustacean, and the largest effort for any crab species. Our assembly and clustering results suggest that our porcelain crab EST data set is equally diverse to the much larger EST set generated in the Daphnia pulex genome sequencing project, and thus will be an important resource to the Daphnia research community. Our homology results support the pancrustacea hypothesis and suggest that Malacostraca may be ancestral to Branchiopoda and Hexapoda. Our results also suggest that our cDNA microarrays cover as much of the

  13. The inner knot of the Crab nebula

    CERN Document Server

    Lyutikov, Maxim; Porth, Oliver

    2015-01-01

    We model the inner knot of the Crab Nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler-beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, $\\sigma \\leq 1$. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar $\\ge 45^\\circ$; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this i...

  14. Pulse profile stability of the Crab pulsar

    Institute of Scientific and Technical Information of China (English)

    Chetana Jain; Biswajit Paul

    2011-01-01

    We present an X-ray timing analysis of the Crab pulsar,PSR B0531+21,using archival RXTE data.We have investigated the stability of the Crab pulse profile,in soft (2-20keV) and hard (30-100keV) X-ray energies,over the last decade of RXTE operation.The analysis includes measurement of the separation between the two pulse peaks and the intensity and widths of the two peaks.We did not find any significant time dependency in the pulse shape.The two peaks have been stable in phase,intensity and width for the last ten years.The first pulse is relatively stronger at soft X-rays.The first pulse peak is narrower than the second peak in both soft and hard X-ray energies.Both the peaks show a slow rise and a steeper fall.The ratio of the pulsed photons in the two peaks is also constant in time.

  15. AFSC/RACE/SAP/Long: Data from: Effects of Ocean Acidification on Juvenile Red King Crab (Paralithodes camtschaticus) and Tanner Crab (Chionoecetes bairdi) Growth, Condition, Calcification, and Survival

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is the results of a laboratory experiment. Juvenile red king crab and Tanner crab were reared in individual containers for nearly 200 days in flowing...

  16. The Effects of Season and Sex on the Nutritional Quality of Muscle Types of Blue Crab Callinectes sapidus and Swimming Crab Portunus segnis

    Directory of Open Access Journals (Sweden)

    Deniz Ayas

    2016-05-01

    Full Text Available The effects of season and sex on the nutritional quality of muscle types (lump crab meatLCM, claw crab meat-CCM of swimming crab (Portunus segnis and blue crab (Callinectes sapidus were investigated. Carapace width, carapace length and total weight of both crab species were measured. High protein content in spring and low protein content in autumn were observed for both crab species. The levels of lipid content of both crab species were found to be similar. Higher lipid contents in spring and winter, lower lipid contents in summer and autumn for both sexes were found. Although both crab species contain small amounts of fat, they are good sources of n-3 PUFA content (especially EPA and DHA for all seasons regardless of sex and muscle types.

  17. Comparison of automated BAX polymerase chain reaction and standard culture methods for detection of Listeria monocyogenes in blue crab meat (Callinectus sapidus) and blue crab processing plants

    Science.gov (United States)

    This study compared the BAX Polymerase Chain Reaction method (BAX PCR) with the Standard Culture Method (SCM) for detection of L. monocytogenes in blue crab meat and crab processing plants. The aim of this study was to address this data gap. Raw crabs, finished products and environmental sponge samp...

  18. Evolutionary history of true crabs (Crustacea: Decapoda: Brachyura) and the origin of freshwater crabs.

    Science.gov (United States)

    Tsang, Ling Ming; Schubart, Christoph D; Ahyong, Shane T; Lai, Joelle C Y; Au, Eugene Y C; Chan, Tin-Yam; Ng, Peter K L; Chu, Ka Hou

    2014-05-01

    Crabs of the infra-order Brachyura are one of the most diverse groups of crustaceans with approximately 7,000 described species in 98 families, occurring in marine, freshwater, and terrestrial habitats. The relationships among the brachyuran families are poorly understood due to the high morphological complexity of the group. Here, we reconstruct the most comprehensive phylogeny of Brachyura to date using sequence data of six nuclear protein-coding genes and two mitochondrial rRNA genes from more than 140 species belonging to 58 families. The gene tree confirms that the "Podotremata," are paraphyletic. Within the monophyletic Eubrachyura, the reciprocal monophyly of the two subsections, Heterotremata and Thoracotremata, is supported. Monophyly of many superfamilies, however, is not recovered, indicating the prevalence of morphological convergence and the need for further taxonomic studies. Freshwater crabs were derived early in the evolution of Eubrachyura and are shown to have at least two independent origins. Bayesian relaxed molecular methods estimate that freshwater crabs separated from their closest marine sister taxa ~135 Ma, that is, after the break up of Pangaea (∼200 Ma) and that a Gondwanan origin of these freshwater representatives is untenable. Most extant families and superfamilies arose during the late Cretaceous and early Tertiary.

  19. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  20. Crab Orchard National Wildlife Refuge: Annual Narrative: Calender year 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1997 calendar year. The report begins with an...

  1. Narrative report : 1972 [Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1972 calendar year. The report begins by...

  2. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1957. The report begins by summarizing...

  3. Narrative report : 1973 [Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1973 fiscal year. The report begins by summarizing...

  4. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1956. The report begins by summarizing the...

  5. Narrative report : 1969. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1969 calendar year. The report begins by...

  6. Narrative report : 1971. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1971 calendar year. The report begins by...

  7. Narrative report : 1970. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1970 calendar year. The report begins by...

  8. EVOLUTION OF THE CRAB NEBULA IN A LOW ENERGY SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haifeng; Chevalier, Roger A., E-mail: hy4px@virginia.edu, E-mail: rac5x@virginia.edu [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

    2015-06-20

    The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy (∼10{sup 50} erg). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.

  9. Evolution of the Crab nebula in a low energy supernova

    CERN Document Server

    Yang, Haifeng

    2015-01-01

    The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy ($\\sim 10^{50}$ ergs). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.

  10. The surprising Crab pulsar and its nebula: a review.

    Science.gov (United States)

    Bühler, R; Blandford, R

    2014-06-01

    The Crab nebula and its pulsar (referred to together as 'the Crab') have historically played a central role in astrophysics. True to this legacy, several unique discoveries have been made recently. The Crab was found to emit gamma-ray pulsations up to energies of 400 GeV, beyond what was previously expected from pulsars. Strong gamma-ray flares, of durations of a few days, were discovered from within the nebula, while the source was previously expected to be stable in flux on these time scales. Here we review these intriguing and suggestive developments. In this context we give an overview of the observational properties of the Crab and our current understanding of pulsars and their nebulae.

  11. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1949

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1949. The report begins by...

  12. Crab Orchard National Wildlife Refuge Narrative report : November - December, 1946

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from November through December of 1946. The report begins by...

  13. Crab Orchard National Wildlife Refuge [Narrative report : September - December, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1953. The report begins by...

  14. Narrative report : 1967. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1967 calendar year. The report begins by...

  15. Crab Orchard National Wildlife Refuge : Furbearer Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Furbearer Management Plan directs the management and regulation of trapping. The furbearer management program directly...

  16. Economic Assessment of the Atlantic Coast Horseshoe Crab Fishery

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In this report, Industrial Economics, Incorporated (lEc) provides an assessment of the economic value of the Atlantic Coast horseshoe crab fishery. We accomplish...

  17. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1950. The report begins by summarizing the...

  18. Narrative report : 1965. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1965 calendar year. The report begins by...

  19. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1952

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1952. The report begins by...

  20. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1953. The report begins by summarizing the...

  1. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1951

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1951. The report begins by...

  2. Narrative report : 1964. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1964 calendar year. The report begins by...

  3. Narrative report : 1968. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1968 calendar year. The report begins by...

  4. Crab Orchard National Wildlife Refuge [Narrative report : January - April, 1954

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1954. The report begins by summarizing...

  5. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1954

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1954. The report begins by...

  6. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1955. The report begins by...

  7. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1949

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1949. The report begins by summarizing...

  8. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1948

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1948. The report begins by summarizing...

  9. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1956. The report begins by...

  10. Removal of nickel from aqueous solutions using crab shells.

    Science.gov (United States)

    Pradhan, Swapna; Shukla, Shyam S; Dorris, Kenneth L

    2005-10-17

    Partially converted crab shell waste, which contains chitosan, was used to remove nickel from water. The chelating ability of chitosan makes it an excellent adsorbent for removing pollutants. Advantages of chitosan in crab shells include availability, low cost, and high biocompatibility. The metal uptake by partially converted crab shell waste was successful and rapid. The sorption occurred primarily within 5 min. The sorption mechanism appears to be quite complicated and cannot be adequately described by either the Langmuir or Freundlich theories. Various anions, including chloride, bromide, fluoride, acetate, sulfate, nitrate, and phosphate, were found to have a very small effect on the capacity of the crab shells for uptake of nickel. The effect of pH was also found not to be prominent.

  11. Crab cavities: Past, present, and future of a challenging device

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    In two-ring facilities operating with a crossing-angle collision scheme, luminosity can be limited due to an incomplete overlapping of the colliding bunches. Crab cavities then are introduced to restore head-on collisions by providing the destined opposite deflection to the head and tail of the bunch. An increase in luminosity was demonstrated at KEKB with global crab-crossing, while the Large Hardron Collider (LHC) at CERN currently is designing local crab crossing for the Hi-Lumi upgrade. Future colliders may investigate both approaches. In this paper, we review the challenges in the technology, and the implementation of crab cavities, while discussing experience in earlier colliders, ongoing R&D, and proposed implementations for future facilities, such as HiLumi-LHC, CERN’s compact linear collider (CLIC), the international linear collider (ILC), and the electron-ion collider under design at BNL (eRHIC).

  12. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1951

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1951. The report begins by summarizing the...

  13. Crab Orchard National Wildlife Refuge [Narrative report : January - April, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1953. The report begins by summarizing...

  14. Crab Orchard National Wildlife Refuge : Wilderness Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Wilderness Management Plan is a general plan which outlines the Refuge management objectives, wilderness creation and...

  15. Crab Orchard National Wildlife Refuge : Wildlife Inventory Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Wildlife Inventory Plan outlines the strategy, techniques and purpose of a wildlife inventory on the Refuge. Futhermore the...

  16. Narrative report : 1966. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1966 calendar year. The report begins by...

  17. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1952

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1952. The report begins by summarizing the...

  18. Crab Orchard National Wildlife Refuge [Narrative report : January - April, 1952

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1952. The report begins by summarizing...

  19. AFSC/REFM: BSAI Crab Economic Data Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Economic data collected for years 1998, 2001, 2004, and 2005 and onward for the BSAI Crab Economic Data Report (EDR). Reporting is required of any owner or...

  20. Breeding of the land crab Cardiosoma armatum (Herklots 1851) in ...

    African Journals Online (AJOL)

    SARAH

    2015-12-31

    Dec 31, 2015 ... the growth performance of the land crab, the ability to domesticate (water and ... experimental pens represented three sexual treatments (two replicates each) including the control of growth in ..... Journal of Crustacean Biology,.

  1. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1950. The report begins by...

  2. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1954

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1954. The report begins by summarizing the...

  3. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1955. The report begins by summarizing the...

  4. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1956. The report begins by summarizing...

  5. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1948

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1948. The report begins by summarizing the...

  6. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1950. The report begins by summarizing...

  7. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1948

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1948. The report begins by...

  8. The Trail Inventory of Crab Orchard NWR [Cycle 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to create a baseline inventory of all non-motorized trails on Crab Orchard National Wildlife Refuge. Trails in this inventory are...

  9. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1955. The report begins by summarizing...

  10. Crab Orchard National Wildlife Refuge : Law Enforcement Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Law Enforcement Plan clarifies U.S. Fish and Wildlife enforcement policies as they apply to the Refuge. It provides...

  11. AFSC/RACE/SAP/Urban: Golden King Crab tagging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is comprised of the records of individual male golden king crab (GKC) tagged at the Kodiak Laboratory. Initial size, shell condition and missing limbs was...

  12. Crab Cavities: Past, Present, and Future of a Challenging Device

    CERN Document Server

    Wu, Q

    2015-01-01

    In two-ring facilities operating with a crossing-angle collision scheme, luminosity can be limited due to an incomplete overlapping of the colliding bunches. Crab cavities then are introduced to restore head-on collisions by providing the destined opposite deflection to the head and tail of the bunch. An increase in luminosity was demonstrated at KEKB with global crab- crossing, while the Large Hardron Collider (LHC) at CERN currently is designing local crab crossing for the Hi-Lumi upgrade. Future colliders may investigate both approaches. In this paper, we review the challenges in the technology, and the implementation of crab cavities, while discussing experience in earlier colliders, ongoing R&D, and proposed implementations for future facilities, such as HiLumi-LHC, CERN’s compact linear collider (CLIC), the international linear collider (ILC), and the electronion collider under design at BNL (eRHIC).

  13. Crab Orchard National Wildlife Refuge: Annual Narrative: Calender year 2002

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 2002 calendar year. The report begins with an...

  14. Crab Orchard National Wildlife Refuge : Prescribed Fire Plan : 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Prescribed Fire Plan has been developed to meet the station objectives set forth in the Master Plan, by aiding the forest...

  15. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1949

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1949. The report begins by summarizing the...

  16. Crab scars reveal survival advantage of left-handed snails

    OpenAIRE

    Dietl, Gregory P.; Hendricks, Jonathan R.

    2006-01-01

    Biological asymmetries are important elements of the structure and function of many living organisms. Using the Plio–Pleistocene fossil record of crab predation on morphologically similar pairs of right- and left-handed snail species, we show here for the first time, contrary to traditional wisdom, that rare left-handed coiling promotes survival from attacks by right-handed crabs. This frequency-dependent result influences the balance of selection processes that maintain left-handedness at th...

  17. Crab-mediated phenotypic changes in Spartina densiflora Brong.

    Science.gov (United States)

    Bortolus, Alejandro; Laterra, Pedro; Iribarne, Oscar

    2004-01-01

    Although plant phenotypic plasticity has been historically studied as an important adaptive strategy to overcome herbivory and environmental heterogeneity, there are several aspects of its ecological importance that remain controversial. The burrowing crab Chasmagnathus granulata eats Spartina densiflora, and also causes several geomorphologic changes that indirectly affect Spartina growth. Here we evaluate if this crab affects the sexual reproductive effort of S. densiflora by mediating changes in plant phenotypic plasticity (i.e., shape of leaves and spikes) while affecting aboveground production, and if these effects interact with disturbance intensity. We conducted local and regional surveys and two-year field experiments manipulating the density of crabs in a mature Spartina marsh where we clipped at ground level different 1×1 m marsh areas to create and compare crab's effect on young (plants growing after the clipping) and mature (unclipped) Spartina stands. Our results suggest that crabs mediate the phenotypic plasticity of sexual reproductive structures of Spartina. Crabs induced an increase in seed production (up to 721%) and seed viability, potentially favoring Spartina dispersal and colonization of distant sites. This effect appears to be maximal when combined with the experimental clipping disturbance. Crabs also exerted a strong effect on clipped plants by increasing the number of standing dead stems and decreasing the photosynthetic area and leaf production. These effects disappear in about two years if no other disturbance occurs. An a posteriori regional field survey agreed with our experimental results corroborating the prediction that plants in old undisturbed marshes have lower sexual reproductive effort than plants in highly disturbed marshes populated by burrowing-herbivore crabs. All these phenotypic changes have important taxonomic and macro-ecological implications that should not be ignored in discussions of applied ecology and

  18. Morphometric characteristics in the horseshoe crab Tachypleus gigas (Arthropoda: Merostomata)

    Digital Repository Service at National Institute of Oceanography (India)

    Vijayakumar, R.; Das, S.; Chatterji, A.; Parulekar, A.H.

    and uniform as also indicated by linear reiationship. It appears, therefore that the energy gained by these crabs from ingested food gets evenly distributed in the body building processes. Telson length-total length relationship indicated a linear... was of highest magnitude than that of the total length. In the length range 300-400 mm, the weight increased sharply. The increase in the soft body parts could probably be due to increased feeding efficiency and food availability to horseshoe crabs. Carapace...

  19. Lincoln Co. Scrap Metal, Crab Orchard, Kentucky

    Science.gov (United States)

    The City of Crab Orchard, KY (population less than 1,000) received a $200,000 EPA Brownfields cleanup grant in 2010 to cleanup up the Lincoln County ScrapMetal property. The site, a former scrap metal recycler and general junkyard, was located in the middle of downtown. The city has experienced a dramatic decline in growth over the past few years. The abandoned two-acre site is located in the city’s center, directly across the street from City Hall. It is the largest property on Main Street. The property was an eyesore, and posed potential health risks to area residents, and deterred investment. Its blighted status did little to help the commercial and private properties that surround it. The site was also home to a dilapidated building that once served as the Odd Fellows meeting hall.

  20. Crab pulsar timing 1982-87

    Science.gov (United States)

    Lyne, A. G.; Pritchard, R. S.; Smith, F. G.

    1988-08-01

    Observations of the arrival times of pulses from the pulsar in the Crab Nebula over a six-year interval are presented. The data are intended to permit the investigation of the interior of the neutron star through the study of glitches and timing noise and to provide an ephemeris for high-energy observations. The first and second frequency derivatives provide a value for the braking index of n = 2.509 + or - 0.001, which is consistent with previous observations. The third frequency derivative can now be determined over an 18-yr span and is as expected for this braking index. The predominant deviations from a simple slow-down model form a sinusoid with a period of 20 months, attributable to an oscillation of the bulk of the neutron superfluid in the pulsar. One conspicuous glitch occurred in August, 1986 and the subsequent recovery was studied from only one hour after the event.

  1. Dusty globules in the Crab Nebula

    Science.gov (United States)

    Grenman, T.; Gahm, G. F.; Elfgren, E.

    2017-03-01

    Context. Dust grains are widespread in the Crab Nebula. A number of small, dusty globules, are visible as dark spots against the background of continuous synchrotron emission in optical images. Aims: Our aim is to catalogue such dusty globules and investigate their properties. Methods: From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. Results: The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 × 10-6M⊙, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of 60 to 1600 km s-1, along with the general expansion of the remnant. We discuss various hypotheses for the formation of globules in the Crab Nebula. Based on observations collected with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute.

  2. REPERCUSSÕES DO PROJETO UCA NA QUALIDADE DE VIDA DO TRABALHO EM ESCOLAS PÚBLICAS DE ROLIM DE MOURA – RONDÔNIA

    Directory of Open Access Journals (Sweden)

    Marcos Tadeu Simões Piacentini

    2015-07-01

    Full Text Available O objetivo desse estudo é analisar as repercussões do Projeto Um Computador por Aluno na qualidade de vida no trabalho no contexto educacional. Nesse estudo comparado, de enfoque descritivo, adotou-se como estratégia investigativa a utilização de métodos mistos sequenciais com as variáveis de estudo embasadas no Modelo de Walton (1973. Constatou-se que os servidores da escola participante do Projeto UCA apresentam uma percepção significativamente negativa de QVT. Os fatores que mais influenciaram no resultado da pesquisa referem-se à insatisfação dos trabalhadores quanto às adequações ergonômicas do local de trabalho e aos recursos tecnológicos disponibilizados para o desempenho de suas atividades.

  3. 76 FR 4635 - Proposed Information Collection; Comment Request; Economic Expenditure Survey of Golden Crab...

    Science.gov (United States)

    2011-01-26

    ... Expenditure Survey of Golden Crab Fishermen in the U.S. South Atlantic Region AGENCY: National Oceanic and... National Marine Fisheries Service (NMFS) proposes to collect economic information from golden-crab...

  4. Spawning migration of the horseshoe crab, Tachypleus gigas (Muller), in relation to lunal cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Rathod, V.; Parulekar, A.H.

    Effects of lunar phases and tidal height on the spawning migration of the horseshoe crab, Tachypleus gigas, along the northeastern coast of India were studied. Mature pairs of crabs migrate towards the shore and build their nests in sandy beaches...

  5. AFSC/RACE/SAP/Long: Data from: Embryo development in golden king crab, Lithodes aequispina.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data from this study, describes embryo development in Golden king crab, Lithodes aequispinus. Six female multiparous golden king crab were captured from the...

  6. Summary of the 1998 Spawning Survey of Horseshoe Crabs Along the Delaware Bay Shore

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The spawning survey of horseshoe crabs was conducted along the shores of Delaware Bay for the ninth year. Counts of spawning horseshoe crabs was performed by trained...

  7. Effect of lunar periodicity on the abundance of crabs from the Goa Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A; Ansari, Z.A; Ingole, B.S.; Sreepada, R.A; Kanti, A; Parulekar, A

    Lunar periodicity showed a significant influence on the occurrence of edible crabs (@iPortunus pelagicus, Charybdis cruciata and Portunus sanguinolentus@@). High density of these crabs was recorded in the trawl catches during full moon and new moon...

  8. Super-Acceleration in the Flaring Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Tavani, Marco, E-mail: marco.tavani@inaf.it

    2013-10-15

    The Crab Nebula continues to surprise us. The Crab system (energized by a very powerful pulsar at the center of the Supernova Remnant SN1054) is known to be a very efficient particle “accelerator” which can reach PeV energies. Today, new surprising data concerning the gamma-ray flares produced by the Crab Nebula challenge models of particle acceleration. The total energy flux from the Crab has been considered for many decades substantially stable at X-ray and gamma-ray energies. However, this paradigm was shattered by the AGILE discovery and Fermi confirmation in September 2010 of transient gamma-ray emission from the Crab. Indeed, we can state that four major flaring gamma-ray episodes have been detected by AGILE and Fermi during the period mid-2007/2012. During these events, transient particle acceleration occurs in a regime which apparently violates the MHD conditions and synchrotron cooling constraints. This fact justifies calling “super-acceleration” the mechanism which produces the “flaring Crab phenomenon”. Radiation between 50 MeV and a few GeV is emitted with a quite hard spectrum within a short timescale (hours-days), with no obvious relation with simultaneous optical and X-ray emissions in the inner Nebula. “Super-acceleration” implies overcoming synchrotron cooling by strong (and “parallel”) electric fields most likely produced by magnetic field reconnection within the pulsar wind outflow. This acceleration appears to be very efficient and, remarkably, limited by radiation reaction. It is not clear at the moment where in the Nebula this phenomenon occurs. An intense observational program is now focused on the Crab Nebula to resolve its most challenging mystery.

  9. Design and prototyping of HL-LHC double quarter wave crab cavities for SPS test

    Energy Technology Data Exchange (ETDEWEB)

    Verdu-Andres, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Skaritka, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wu, Q. [Brookhaven National Lab. (BNL), Upton, NY (United States); Xiao, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Belomestnykh, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States); Alberty, L. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Artoos, K. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Calaga, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Capatina, O. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Capelli, T. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Carra, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Leuxe, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Kuder, N. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Zanoni, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Li, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ratti, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-05-03

    The LHC high luminosity project envisages the use of the crabbing technique for increasing and levelling the LHC luminosity. Double Quarter Wave (DQW) resonators are compact cavities especially designed to meet the technical and performance requirements for LHC beam crabbing. Two DQW crab cavities are under fabrication and will be tested with beam in the Super Proton Synchrotron (SPS) at CERN by 2017. This paper describes the design and prototyping of the DQW crab cavities for the SPS test.

  10. Design and Prototyping of HL-LHC Double Quarter Wave Crab Cavities for SPS Test

    CERN Document Server

    Verdú-Andrés, S; Wu, Q; Xiao, B P; Belomestnykh, S; Ben-Zv, I; Alberty, L; Artoos, Kurt; Calaga, Rama; Capatina, Ofelia; Capelli, Teddy; Carra, Federico; Leuxe, Raphael; Kuder, Norbert; Zanoni, Carlo; Li, Z; Ratti, A

    2015-01-01

    The LHC high luminosity project envisages the use of the crabbing technique for increasing and levelling the LHC luminosity. Double Quarter Wave (DQW) resonators are compact cavities especially designed to meet the technical and performance requirements for LHC beam crabbing. Two DQW crab cavities are under fabrication and will be tested with beam in the Super Proton Synchrotron (SPS) at CERN by 2017. This paper describes the design and prototyping of the DQW crab cavities for the SPS test.

  11. Observations of the Crab Nebula and Pulsar with VERITAS

    CERN Document Server

    Celik, O

    2007-01-01

    Observations of the Crab Nebula have proven to be the best tool to calibrate and to characterize the performance of a Cherenkov telescope. Scientifically, it is interesting to measure the energy spectrum of the Crab Nebula close to the inverse-Compton peak where a deviation is expected from the power law seen at energies above 300 GeV. Additionally, it is important to search for pulsed emission from the Crab Pulsar at energies beyond the 10 GeV upper limit of the EGRET pulsar detection. Since current models predict a cut-off in pulsed emission between 10 and 100 GeV, measurements at energies close to this range may help to discriminate between them. We observed the Crab extensively in the 2006-2007 season during the VERITAS 2- and 3-telescope commissioning phases. Using this data set we reconstructed a preliminary energy spectrum of the signal from the Crab Nebula. We also measured the optical pulsed signal to validate our GPS time-stamping and barycentering techniques and obtained an upper limit for the puls...

  12. H2 Temperatures in the Crab Nebula

    CERN Document Server

    Loh, E D; Ferland, G J; Curtis, Z K; Richardson, C T; Fabian, A C; Salomé, P

    2011-01-01

    We used K-band spectra to measure the H2 excitation temperatures in six molecular knots associated with the filaments in the Crab Nebula. The temperatures are quite high - in the range T ~ 2000-3000K, just below the H2 dissociation temperature. This is the temperature range over which the H2 1-0 S(1) line at 2.121\\mum has its maximum emissivity per unit mass, so there may be many additional H2 cores with lower temperatures that are too faint to detect. We also measured the electron density in adjacent ionized gas, which on the assumption of gas pressure balance indicates densities in the molecular region n_mol ~ 20,000 H baryons cm-3, although this really is just a lower limit since the H2 gas may be confined by other means. The excited region may be just a thin skin on a much more extensive blob of molecular gas that does not have the correct temperature and density to be as easily detectable. At the opposite extreme, the observed knots could consist of a fine mist of molecular gas in which we are detecting ...

  13. Radio Emission Physics in the Crab Pulsar

    CERN Document Server

    Eilek, J A

    2016-01-01

    We review our high-time-resolution radio observations of the Crab pulsar and compare our data to a variety of models for the emission physics. The Main Pulse and the Low-Frequency Interpulse come from regions somewhere in the high-altitude emission zones (caustics) that also produce pulsed X-ray and gamma-ray emission. Although no emission model can fully explain these two components, the most likely models suggest they arise from a combination of beam-driven instabilities, coherent charge bunching and strong electromagnetic turbulence. Because the radio power fluctuates on a wide range of timescales, we know the emission zones are patchy and dynamic. It is tempting to invoke unsteady pair creation in high-altitude gaps as source of the variability, but current pair cascade models cannot explain the densities required by any of the likely models. It is harder to account for the mysterious High-Frequency Interpulse. We understand neither its origin within the magnetosphere nor the striking emission bands in it...

  14. The crab cavities cryomodule for SPS test

    Science.gov (United States)

    Zanoni, C.; Amorim Carvalho, A.; Artoos, K.; Atieh, S.; Brodzinski, K.; Calaga, R.; Capatina, O.; Capelli, T.; Carra, F.; Dassa, L.; Dijoud, T.; Eiler, K.; Favre, G.; Freijedo Menendez, P.; Garlaschè, M.; Giordanino, L.; Jones, T.; E Langeslag, S. A.; Leuxe, R.; Mainaud-Durand, H.; Minginette, P.; Narduzzi, M.; Rude, V.; Sosin, M.; Swieszek, J. S.; Templeton, N.

    2017-07-01

    RF Crab Cavities are an essential part of the HL-LHC upgrade. Two concepts of such systems are being developed: the Double Quarter Wave (DQW) and the RF Dipole (RFD). A cryomodule with two DQW cavities is in advanced fabrication stage for the tests with protons in the SPS. The cavities must be operated at 2 K, without excessive heat loads, in a low magnetic environment and in compliance with CERN safety guidelines on pressure and vacuum systems. A large set of components, such as a thermal shield, a two layers magnetic shield, RF lines, helium tank and tuner are required for the successful and safe operation of the cavities. The sum of all these components with the cavities and their couplers forms the cryomodule. An overview of the design and fabrication strategy of this cryomodule is presented. The main components are described along with the present status of cavity fabrication and processing and cryomodule assembly. The lesson learned from the prototypes and first manufactured systems are also included.

  15. 76 FR 47155 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-08-04

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program; Public Meeting AGENCY: National... crab fisheries managed under the BSAI Crab Rationalization program. The CIE, operated by Northern Taiga... products. The BSAI Crab Economic Data Report (EDR) program administered by NMFS began collecting...

  16. 77 FR 44216 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2012-07-27

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... recovery under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2012/2013 crab fishing year....

  17. 76 FR 43658 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-07-21

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2011/2012 crab fishing year so...

  18. 75 FR 43147 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2010-07-23

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2010/2011 crab fishing year so...

  19. 78 FR 46577 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-08-01

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2013/2014 crab fishing year so...

  20. 75 FR 49420 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-08-13

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In... (TAC) and corresponding fleet days-at-sea (DAS) allocation for the Atlantic deep- sea red crab fishery... the implementing regulations for the Atlantic Deep- Sea Red Crab Fishery Management Plan...

  1. 75 FR 7435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-02-19

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications... Atlantic deep-sea red crab fishery, including a target total allowable catch (TAC) and a fleet-wide days-at-sea (DAS) allocation. The implementing regulations for the Atlantic Deep-Sea Red Crab...

  2. 75 FR 35435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-06-22

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In... finalized 2010 specifications for the Atlantic deep-sea red crab fishery, including a target total allowable... Atlantic Deep-Sea Red Crab Fishery Management Plan (FMP) allow NMFS to make an in-season adjustment to...

  3. Respiration and heart rate in exercising land crabs.

    Science.gov (United States)

    Herreid, C F; Lee, L W; Shah, G M

    1979-05-01

    Land Crabs, Cardisoma guanhumi, were fitted with respiratory masks and E.C.G. electrodes and run for 10 or 20 min on a treadmill at speeds of 150 and 300 cm/min. Aerobic metabolism increased linearly with the speed of locomotion. The recovery period was characterized by a large oxygen debt. The primary respiratory adjustment to exercise was an increased ventilation volume; only a minor increase in oxygen extraction occurred. The respiratory exchange ratio increased during exercise and during recovery, presumably correlated with a metabolic acidosis. These results are similar to data collected for exercising vertebrates and the net cost of locomotion of crabs appears similar to quadrupeds. However, the heart rate in exercising crabs changed in an unexpected way: during moderate exercise no change was noted, but during heavy exercise a bradycardia developed. The reduction in rate resulted from an increase in interbeat interval and frequent pauses in the heart beat.

  4. Double lethal coconut crab (Birgus latro L.) poisoning.

    Science.gov (United States)

    Maillaud, C; Lefebvre, S; Sebat, C; Barguil, Y; Cabalion, P; Cheze, M; Hnawia, E; Nour, M; Durand, F

    2010-01-01

    We report a double lethal coconut crab Birgus latro L. poisoning in New Caledonia. Both patients died after showing gastro-intestinal symptoms, major bradycardia with marked low blood pressure, and finally asystolia. Both had significative hyperkaliemia, suggesting a digitaline-like substance intoxication. Traditional knowledge in the Loyalty Islands relates coconut crab toxicity to the consumption of the Cerbera manghas fruit by the crustacean. Elsewhere previous descriptions of human poisoning with the kernel of fruits of trees belonging to the genus Cerbera, known to contain cardiotoxic cardenolides, appear to be very similar to our cases. Cardenolides assays were performed on patient's serum samples, fruit kernel and on the crustacean guts, which lead us to suppose these two fatal cases were the result of a neriifolin intoxication, this toxin having been transmitted through the coconut crab.

  5. Extreme Particle Acceleration via Magnetic Reconnection in the Crab Nebula

    Science.gov (United States)

    Cerutti, Benoit; Uzdensky, D. A.; Begelman, M. C.

    2012-01-01

    The discovery by Agile and Fermi of intense day-long synchrotron gamma-ray flares above 100 MeV in the Crab Nebula challenges classical models of pulsar wind nebulae and particle acceleration. We argue that the flares are powered by magnetic reconnection in the nebula. Using relativistic test-particle simulations, we show that particles are naturally focused into a thin fan beam, deep inside the reconnection layer where the magnetic field is small. The particles then suffer less from synchrotron losses and pile up at the maximum energy given by the electric potential drop in the layer. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum above 100 MeV is consistent with the September 2010 flare observations. No detectable emission is expected at other wavelengths. This scenario provides a viable explanation for the Crab Nebula gamma-ray flares.

  6. CRAB: the CMS distributed analysis tool development and design

    Energy Technology Data Exchange (ETDEWEB)

    Spiga, D. [University and INFN Perugia (Italy); Lacaprara, S. [INFN Legnaro (Italy); Bacchi, W. [University and INFN Bologna (Italy); Cinquilli, M. [University and INFN Perugia (Italy); Codispoti, G. [University and INFN Bologna (Italy); Corvo, M. [CERN (Switzerland); Dorigo, A. [INFN Padova (Italy); Fanfani, A. [University and INFN Bologna (Italy); Fanzago, F. [CERN (Switzerland); Farina, F. [INFN Milano-Bicocca (Italy); Gutsche, O. [FNAL (United States); Kavka, C. [INFN Trieste (Italy); Merlo, M. [INFN Milano-Bicocca (Italy); Servoli, L. [University and INFN Perugia (Italy)

    2008-03-15

    Starting from 2007 the CMS experiment will produce several Pbytes of data each year, to be distributed over many computing centers located in many different countries. The CMS computing model defines how the data are to be distributed such that CMS physicists can access them in an efficient manner in order to perform their physics analysis. CRAB (CMS Remote Analysis Builder) is a specific tool, designed and developed by the CMS collaboration, that facilitates access to the distributed data in a very transparent way. The tool's main feature is the possibility of distributing and parallelizing the local CMS batch data analysis processes over different Grid environments without any specific knowledge of the underlying computational infrastructures. More specifically CRAB allows the transparent usage of WLCG, gLite and OSG middleware. CRAB interacts with both the local user environment, with CMS Data Management services and with the Grid middleware.

  7. CRAB: the CMS distributed analysis tool development and design

    CERN Document Server

    Spiga, D; Bacchi, W; Cinquilli, M; Codispoti, G; Corvo, M; Dorigo, A; Fanfani, A; Fanzago, F; Farina, F; Gutsche, O; Kavka, C; Merlo, M; Servoli, L

    2008-01-01

    Starting from 2007 the CMS experiment will produce several Pbytes of data each year, to be distributed over many computing centers located in many different countries. The CMS computing model defines how the data are to be distributed such that CMS physicists can access them in an efficient manner in order to perform their physics analysis. CRAB (CMS Remote Analysis Builder) is a specific tool, designed and developed by the CMS collaboration, that facilitates access to the distributed data in a very transparent way. The tool's main feature is the possibility of distributing and parallelizing the local CMS batch data analysis processes over different Grid environments without any specific knowledge of the underlying computational infrastructures. More specifically CRAB allows the transparent usage of WLCG, gLite and OSG middleware. CRAB interacts with both the local user environment, with CMS Data Management services and with the Grid middleware.

  8. A New HST Measurement of the Crab Pulsar Proper Motion

    CERN Document Server

    Caraveo, P A; Caraveo, Patrizia A.; Mignani, Roberto P.

    1999-01-01

    We have used a set of archived HST/WFPC2 exposures of the inner regions of the Crab Nebula to obtain a new measurement of the pulsar proper motion, the first after the original work of Wyckoff & Murray, more than 20 years ago. Our measurement of the pulsar displacement, mu = 18 +/- 3 mas/yr, agrees well with the value obtained previously. This is noteworthy, since the data we have used span less than 2 years, as opposed to the 77 years required in the previous work. With a position angle of 292 +/- 10 deg, the proper motion vector appears aligned with the axis of symmetry of the inner Crab nebula, as defined by the direction of the X-ray jet observed by ROSAT. Indeed, if the neutron star rotation is to be held responsible both for the X-ray jet and for the observed symmetry, the Crab could provide an example of alignment between spin axis and proper motion.

  9. Design and Prototyping of a 400 MHz RF-dipole Crabbing Cavity for the LHC High-Luminosity Upgrade

    CERN Document Server

    De Silva, S U; Delayen, J R; Li, Z; Nicol, T H

    2015-01-01

    LHC High Luminosity Upgrade is in need of two crabbing systems that deflects the beam in both horizontal and vertical planes. The 400 MHz rf-dipole crabbing cavity system is capable of crabbing the proton beam in both planes. At present we are focusing our efforts on a complete crabbing system in the horizontal plane. Prior to LHC installation the crabbing system will be installed for beam test at SPS. The crabbing system consists of two rfdipole cavities in the cryomodule. This paper discusses the electromagnetic design and mechanical properties of the rf-dipole crabbing system for SPS beam test.

  10. Preliminary survey of a nemertean crab egg predator, Carcinonemertes, on its host crab, Callinectes arcuatus (Decapoda, Portunidae) from Golfo de Nicoya, Pacific Costa Rica

    Science.gov (United States)

    Okazaki, Robert K.; Wehrtmann, Ingo S.

    2014-01-01

    Abstract The possible presence of egg predators in brood masses of portunid crabs from Pacific Central America has not been studied yet. This survey reports the finding of a nemertean crab egg predator on the portunid crab, Callinectes arcuatus, from the Golfo de Nicoya, Pacific Costa Rica. Nemerteans were found in the egg masses of 26 out of the 74 crabs for a prevalence of 35%. The intensity (mean number of worms/ infected crab) was estimated to be 18 with a variance of 1–123 worms/infected crab. No nemerteans were observed either in the 19 Callinectes arcuatus from Golfo Dulce (southern Pacific coast) and the 10 Portunus asper from Herradura-Jaco (central Pacific coast). This nemertean is a member of the genus Carcinonemertes, which has been reported from the Caribbean coast of Panama. However, the encountered Carcinonemertes sp. is the first published finding and report from Costa Rica and Pacific Central America. PMID:25561848

  11. Biodiversity of Crabs in Pichavaram Mangrove Environment, South East Coast of India

    Directory of Open Access Journals (Sweden)

    T. Kannupandi

    2008-01-01

    Full Text Available In this study, the distribution of crabs in Pichavaram was recorded from December 2001 to November 2002 at monthly intervals. The species present on the substratum and on the vegetation area were recorded in quadrant each measuring 1 m2. There are about 36 crabs species are distributed in Pichavaram mangrove environment. Crabs belonging to the family Grapsidae and Ocypodidae are most dominant forms. Substrate suitability; effects of tidal inundation and distribution of mangrove plants were the possible factors that could influence zonation and abundance of the crabs in the Pichavaram mangroves. The reason for depletion of crabs and their conservation measures are also discussed.

  12. Complete mitochondrial genomes of three mitten crabs, Eriocheir sinensis, E. hepuensis, and E. japonica.

    Science.gov (United States)

    Wang, Jun; Huang, Lei; Cheng, Qixuan; Lu, Guoqing; Wang, Chenghui

    2016-01-01

    Taxonomic classification of three mitten crabs (Eriocheir sinensis, E. hepuensis, and E. japonica) has long been controversial. In this study, the complete mitogenomes of the three crabs were reported. The three mitogenomes were conserved in the organization of genes with 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 control region. Nucleotide variations among the crabs were identified in both coding and non-coding regions. In addition, variable numbers of tandem repeats in control region were identified in the mitten crabs. The mitogenome sequences provide a valuable resource to elucidate taxonomic relationship and evolutionary history of the three mitten crabs.

  13. Crab scars reveal survival advantage of left-handed snails.

    Science.gov (United States)

    Dietl, Gregory P; Hendricks, Jonathan R

    2006-09-22

    Biological asymmetries are important elements of the structure and function of many living organisms. Using the Plio-Pleistocene fossil record of crab predation on morphologically similar pairs of right- and left-handed snail species, we show here for the first time, contrary to traditional wisdom, that rare left-handed coiling promotes survival from attacks by right-handed crabs. This frequency-dependent result influences the balance of selection processes that maintain left-handedness at the species level and parallels some social interactions in human cultures, such as sports that involve dual contests between opponents of opposite handedness.

  14. Observations of the Crab Nebula with Early HAWC Data

    CERN Document Server

    Greus, Francisco Salesa

    2015-01-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray detector, completed in early 2015. HAWC started science operations in August 2013 with a third of the detector taking data. Several known gamma-ray sources have already been detected with the first HAWC data. Among these sources, the Crab Nebula, the brightest steady gamma-ray source at very high energies in our Galaxy, has been detected with high significance. In this contribution I will present the results of the observations of the Crab Nebula with HAWC, including time variability, and the detector performance based on early data.

  15. Species Diversity and Abundance of Marine Crabs (Portunidae: Decapoda) from a Collapsible Crab Trap Fishery at Kung Krabaen Bay, Chanthaburi Province, Thailand

    Science.gov (United States)

    Kunsook, Chutapa; Dumrongrojwatthana, Pongchai

    2017-01-01

    The diversity and abundance of marine crabs from a collapsible crab trap fishery at Kung Krabaen Bay, Gulf of Thailand, were observed from August 2012 to June 2013 using 10 sampling stations. The results showed that there were seven families, 11 genera and 17 species (two anomuran and 15 brachyuran crabs). The two anomuran species were Clibanarius virescens (1,710 individuals) and Clibanarius infraspinatus (558 individuals). For brachyuran crabs, Portunidae was the most common family, including 10 species. The dominant species of brachyuran crabs included Thalamita crenata (897 individuals), Portunus pelagicus (806 individuals), Charybdis affinis (344 individuals), Scylla sp. (201 individuals), and Charybdis anisodon (100 individuals). The abundance of crabs was affected by the habitat type. Anomuran crabs had the highest abundance in Halodule pinifolia seagrass beds, whilst brachyurans had the highest abundance in Enhalus acoroides seagrass beds. The dominant brachyuran species were found in pelagic areas near the bay mouth, such as P. pelagicus, P. sanguinolentus, C. feriatus, C. helleri, C. natator, C. affinis, and M. hardwickii. Lastly, reforested mangroves were important habitats for Scylla tranquebarica and C. anisodon. Seasonal and physical factors influenced the abundance of some crabs, for example, the abundance of C. virescens was correlated with temperature, and the abundance of T. crenata was correlated with transparency depth. Our results revealed that Kung Krabaen Bay serves as the home to many marine crab species; however, our results also revealed that 49% of the harvested crabs (2,308 out of 4,694 individuals) were simply discarded and subsequently died. Moreover, our research noted that eight non-target species will become target species in the near future. Therefore, research on the reproductive biology of some marine crabs and an improved understanding of the importance of marine crabs by local fishermen are necessary to prevent biodiversity

  16. The use of artificial crabs for testing predatory behavior and health in the octopus.

    Science.gov (United States)

    Amodio, Piero; Andrews, Paul; Salemme, Marinella; Ponte, Giovanna; Fiorito, Graziano

    2014-01-01

    The willingness of the cephalopod mollusc Octopus vulgaris to attack a live crab is traditionally used as a method to assess the overall health and welfare of octopuses in the laboratory. This method requires placing a crab in the home tank of an animal, measuring the time (latency) taken for the octopus to initiate an attack and withdrawing the crab immediately prior to capture. The same crab is commonly used to assess multiple octopuses as part of daily welfare assessment. Growing concern for the welfare of crustaceans and a review of all laboratory practices for the care and welfare of cephalopods following the inclusion of this taxon in 2010/63/EU prompted a study of the utility of an artificial crab to replace a live crab in the assessment of octopus health. On consecutive days O. vulgaris (N=21) were presented with a live, a dead or an artificial crab, and the latency to attack measured. Despite differences in the predatory performance towards the three different crab alternatives, octopuses readily attacked the artificial (and the dead) crab, showing that they can generalize and respond appropriately towards artificial prey. Researchers should consider using an artificial crab to replace the use of a live crab as part of the routine health assessment of O. vulgaris.

  17. Boxer crabs induce asexual reproduction of their associated sea anemones by splitting and intraspecific theft

    Directory of Open Access Journals (Sweden)

    Yisrael Schnytzer

    2017-01-01

    Full Text Available Crabs of the genus Lybia have the remarkable habit of holding a sea anemone in each of their claws. This partnership appears to be obligate, at least on the part of the crab. The present study focuses on Lybia leptochelis from the Red Sea holding anemones of the genus Alicia (family Aliciidae. These anemones have not been found free living, only in association with L. leptochelis. In an attempt to understand how the crabs acquire them, we conducted a series of behavioral experiments and molecular analyses. Laboratory observations showed that the removal of one anemone from a crab induces a “splitting” behavior, whereby the crab tears the remaining anemone into two similar parts, resulting in a complete anemone in each claw after regeneration. Furthermore, when two crabs, one holding anemones and one lacking them, are confronted, the crabs fight, almost always leading to the “theft” of a complete anemone or anemone fragment by the crab without them. Following this, crabs “split” their lone anemone into two. Individuals of Alicia sp. removed from freshly collected L. leptochelis were used for DNA analysis. By employing AFLP (Fluorescence Amplified Fragments Length Polymorphism it was shown that each pair of anemones from a given crab is genetically identical. Furthermore, there is genetic identity between most pairs of anemone held by different crabs, with the others showing slight genetic differences. This is a unique case in which one animal induces asexual reproduction of another, consequently also affecting its genetic diversity.

  18. Boxer crabs induce asexual reproduction of their associated sea anemones by splitting and intraspecific theft.

    Science.gov (United States)

    Schnytzer, Yisrael; Giman, Yaniv; Karplus, Ilan; Achituv, Yair

    2017-01-01

    Crabs of the genus Lybia have the remarkable habit of holding a sea anemone in each of their claws. This partnership appears to be obligate, at least on the part of the crab. The present study focuses on Lybia leptochelis from the Red Sea holding anemones of the genus Alicia (family Aliciidae). These anemones have not been found free living, only in association with L. leptochelis. In an attempt to understand how the crabs acquire them, we conducted a series of behavioral experiments and molecular analyses. Laboratory observations showed that the removal of one anemone from a crab induces a "splitting" behavior, whereby the crab tears the remaining anemone into two similar parts, resulting in a complete anemone in each claw after regeneration. Furthermore, when two crabs, one holding anemones and one lacking them, are confronted, the crabs fight, almost always leading to the "theft" of a complete anemone or anemone fragment by the crab without them. Following this, crabs "split" their lone anemone into two. Individuals of Alicia sp. removed from freshly collected L. leptochelis were used for DNA analysis. By employing AFLP (Fluorescence Amplified Fragments Length Polymorphism) it was shown that each pair of anemones from a given crab is genetically identical. Furthermore, there is genetic identity between most pairs of anemone held by different crabs, with the others showing slight genetic differences. This is a unique case in which one animal induces asexual reproduction of another, consequently also affecting its genetic diversity.

  19. The complete mitogenome of the hydrothermal vent crab Xenograpsus testudinatus (Decapoda, Brachyura) and comparison with brachyuran crabs.

    Science.gov (United States)

    Ki, Jang-Seu; Dahms, Hans-Uwe; Hwang, Jiang-Shiou; Lee, Jae-Seong

    2009-12-01

    In this study, we analyzed the complete mitochondrial (mt) genome of a hydrothermal vent crab Xenograpsus testudinatus (Decapoda: Brachyura) obtained from the hydrothermal vents off Kueishantao Island, Taiwan, which extend from the deep sea Okinawa Trench. The mitogenome of X. testudinatus was 15,796 bp in length and contained the same 37 genes (e.g. 2 rRNAs, 22 tRNAs, and 13 PCGs) found in other metazoan mitogenomes. Analysis of the structural mt gene order in X. testudinatus revealed that the 13 PCGs, excluding a translocation of ND6-Cyt b cluster, were similarly ordered when compared to the pancrustacean ground pattern; however the tRNAs were severely rearranged. Phylogenetic analysis of decapod mitogenomes showed that the molecular taxonomy of the vent crab was in accordance with its morphological systematics. Together, these findings suggest that the vent crab studied here has little mitochondrial genetic variation when compared with morphologically defined conspecifics from other marine habitats.

  20. First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae recruits co-inhabiting burrows of conspecific crabs

    Directory of Open Access Journals (Sweden)

    Anders Jensen Schmidt

    2009-12-01

    Full Text Available Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763, rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

  1. 50 CFR Table 8 to Part 680 - Initial QS and PQS Pool for Each Crab QS Fishery

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Initial QS and PQS Pool for Each Crab QS... Crab QS Fishery Crab QS Fishery Initial QS Pool Initial PQS Pool BBR Bristol Bay red king crab 400,000,000 400,000,000 BSS Bering Sea snow crab (C. opilio) 1,000,000,000 1,000,000,000 EAG Eastern...

  2. Paragonimus ohirai metacercariae in crabs collected along the Arakawa River in Tokyo, Japan.

    Science.gov (United States)

    Sugiyama, Hiromu; Morishima, Yasuyuki; Kameoka, Yosuke; Arakawa, Kyoko; Kawanaka, Masanori

    2004-08-01

    Brackish water crabs infected with Paragonimus ohirai metacercariae have been reported in various regions in Japan. However, infected crabs have not been identified in Tokyo. We therefore collected the crab, Chiromantes dehaani, between August 2002 and July 2003 from 12 locations along the Arakawa River that flows through Tokyo. Of the 922 captured crabs, 177 (19%) from 6 locations were infected with Paragonimus metacercariae. The prevalence of metacercariae at these 6 locations ranged from 5 to 89%. The number of metacercariae per infected crab ranged from 1 to 190, with an average of 13.1. The morphological features of the metacercariae and of adult worms recovered from test rats infected with metacercariae showed that the metacercariae in the infected crabs were P. ohirai Miyazaki, 1939. The ITS2 sequence data support this conclusion. This paper is the first description of P. ohirai infection of crabs in Tokyo.

  3. Distribution of blue swimming crab (Portunus pelagicus Linnaeus, 1758 in Trang Province

    Directory of Open Access Journals (Sweden)

    Buncha Somboonsuke

    2010-07-01

    Full Text Available The fishery of the blue swimming crab (Portunus pelagicus Linnaeus, 1758 is very important to the economy of small-scale fishermen. Greater knowledge about its distribution could lead to more efficient management. This study was conducted in Trang Province from October 2006 to August 2007 using collapsible crab traps. To reveal the spatial distribution of the species, we analyzed the data using geostatistical methods. The standard interpolate procedure was applied to model the crab distribution. There were clear spatial distribution differences among the small crabs, large crabs and ovigerous females in study area. The mapping showed that small crabs (carapace width 10 cm were farther offshore. Ovigerous females peaked in abundance during 2 periods: March – April and August – September. This information can be used to support decision making concerning the designation of fishing zones and the optimization of the blue swimming crab fishery in the study area.

  4. Carriage of Clostridium perfringens by benthic crabs in a sewage-polluted estuary.

    Science.gov (United States)

    La Sala, Luciano F; Redondo, Leandro M; Díaz Carrasco, Juan M; Pereyra, Ana María; Farber, Marisa; Jost, Helen; Fernández-Miyakawa, Mariano E

    2015-08-15

    The Estuary of Bahía Blanca (EBB), Argentina, is an important wetland under intense sewage pollution. We investigated the occurrence of Clostridium perfringens (CP) in populations of two benthic crabs (Neohelice granulata and Cyrtograpsus angulatus) and in sediment from the EBB. CP was found in 49.1% of the crabs and all of the isolates were identified as type A. The alpha (cpa) and enterotoxin (cpe) encoding genes were identified. Genetic analyses identified 13 novel sequence types, and found no clustering among isolates, suggesting that CP is not part of the crabs' commensal flora. CP carriage was 51 times more likely in crabs from the area nearest sewage outfalls compared with crabs from a reference site. Our in vitro experiments suggest that the carriage of CP in crabs is transient. The use of these benthic crabs as monitoring organisms of sewage pollution in coastal habitats is proposed.

  5. RGS X-Ray Spectroscopy of the Crab Nebula

    Science.gov (United States)

    Kaastra, J. S.; de Vries, C. P.; Costantini, E.; den Herder, J. A.

    The Crab nebula and pulsar have been widely used as a calibration source for X-ray instruments. The in-flight effective area calibration of the Reflection Grating Spectrometers (RGS) of XMM-Newton depends upon the availability of reliable calibration sources. We analyse RGS observations of the Crab using different instrument configurations and spatial offsets, and make use of previous determinations of the continuum spectrum of the nebula plus pulsar. Due to the high spectral resolution of the RGS, we resolve the main absorption edges. We get an excellent fit to the Crab spectrum using this fixed continuum and the absorption spectrum determined by RGS. We get accurate column densities for the neutral atoms of H, N, O, Ne, Mg and Fe as well as a clear detection of Fe II and firm upper limits for other ions (O II, Mg II). We find solar-like abundances for N, O and Mg, and Fe (adding Fe I and Fe II), while Ne is overabundant. Finally, we show how we can determine the absolute flux of Crab with high accuracy by combining RGS and Chandra LETGS spectra of different sources.

  6. Substrate use and selection in sympatric intertidal hermit crab species

    Directory of Open Access Journals (Sweden)

    A. TURRA

    Full Text Available Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus coexist in the intertidal region of Pernambuco Islet, Araçá Region, São Sebastião Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud in allopatric (single species and sympatric (three species treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis.

  7. X-ray Pulsar in the Crab Nebula.

    Science.gov (United States)

    Fritz, G; Henry, R C; Meekins, J F; Chubb, T A; Friedman, H

    1969-05-09

    X-ray pulsations have been observed in the Crab Nebula at a frequency closely matching the radio and optical pulsations. About 5 percent of the total x-ray power of the nebula appears in the pulsed component. The x-ray pulsations have the form of a main pulse and an interpulse separated by about 12 milliseconds.

  8. Hard X-ray Variations in the Crab Nebula

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Cherry, M. L.; Case, G. L.; Baumgartner, W. H.; Beklen, E.; Bhat, P. N.; Briggs, M. S.; Camero-Arranz, A.; Connaughton, V.; Finger, M. H.; Gehrels, N.; Greiner, J.; Jahoda, K.; Jenke, P.; Kippen, R. M.; Kouveliotou, C.; Krimm, H. A.; Kuulkers, E.; Meegan, C. A.; Natalucci, L.; Paciesas, W. S.; Preece, R.; Rodi, J. C.; Skinner, G. K.

    2013-01-01

    In the first two years of science operations of the Fermi Gamma-ray Burst Monitor (GBM), August 2008 to August 2010, approximately 7% (70 mcrab) decline was discovered in the overall Crab Nebula flux in the 15 - 50 keV band, measured with the Earth occultation technique. This decline was independently confirmed with four other instruments: the RXTE/PCA, Swift/BAT, INTEGRAL/IBIS, and INTEGRAL/SPI. The pulsed flux measured with RXTE/PCA from 1999-2010 was consistent with the pulsar spin-down, indicating that the observed changes were nebular. From 2001 to 2010, the Crab nebula flux measured with RXTE/ PCA was particularly variable, changing by up to approximately 3.5% per year in the 15-50 keV band. These variations were confirmed with INTEGRAL/SPI starting in 2003, Swift/BAT starting in 2005, and Fermi GBM starting in 2008. Before 2001 and since 2010, the Crab nebula flux has appeared more stable, varying by less than 2% per year. I will present updated light curves in multiple energy bands for the Crab Nebula, including recent data from Fermi GBM, Swift/BAT, INTEGRAL and MAXI, and a 16-year long light curve from RXTE/PCA.

  9. Six years of VERITAS observations of the Crab Nebula

    CERN Document Server

    ,

    2015-01-01

    The Crab Nebula is the brightest source in the very-high-energy (VHE) gamma-ray sky and one of the best studied non-thermal objects. The dominant VHE emission mechanism is believed to be inverse Compton scattering of low energy photons on relativistic electrons. While it is unclear how the electrons in the nebula are accelerated to energies of $10^{16}$ eV, it is general consensus that the ultimate source of energy is the Crab pulsar at the center of the nebula. Studying VHE gamma-ray emission provides valuable insight into the emission mechanisms and ultimately helps to understand the remaining mysteries of the Crab, for example, how the Poynting dominated energy flow is converted into a particle dominated flow of energy. We report on the results of six years of Crab observations with VERITAS comprising 115 hours of data taken between 2007 and 2013. VERITAS is an array of four 12-meter imaging air Cherenkov telescopes located in southern Arizona. We report on the energy spectrum, light curve, and a study of ...

  10. Crab Nebula Variations in Hard X-rays

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    The Crab Nebula was surprisingly variable from 2001-2010, with less variability before 2001 and since mid-2010. We presented evidence for spectral softening from RXTE, Swift/BAT, and Fermi GBM during the mid-2008-2010 flux decline. We see no clear connections between the hard X-ray variations and the GeV flares

  11. Project "Flappy Crab": An Edu-Game for Music Learning

    Science.gov (United States)

    Cardoso Gomes, Cristina Maria; Guerreiro Figueiredo, Mauro Jorge; Bidarra, José; Cardoso Gomes, José Duarte

    2014-01-01

    This paper discusses some possibilities of gamification and remixing process for music education. Analyses also the concepts of gamification, mashup, remix and presents its possible usage in education--music teaching--through the development of the project/educational game "Flappy Crab". The article begins with a brief introduction to…

  12. Hermit Crabs (Decapoda: Anomura: Paguridea) from the Seychelles

    NARCIS (Netherlands)

    McLaughlin, P.A.; Hogarth, P.J.

    1998-01-01

    A report on the hermit crabs collected during the Netherlands Seychelles Expedition, 1992-1993, supplemented by materials collected for Enterprise Oil and examined by one of the authors. Twentyseven species, representing three families, are recognized, including one new genus and four new species.

  13. Cuticular proteins from the horseshoe crab, Limulus polyphemus

    DEFF Research Database (Denmark)

    Ditzel, Nicholas; Andersen, Svend Olav; Højrup, Peter

    2003-01-01

    Proteins were purified from the carapace cuticle of a juvenile horseshoe crab, Limulus polyphemus, and several of them were characterized by amino acid sequence determination. The proteins are small (7-16 kDa) and their isoelectric points range from 6.5 to 9.2. They have high contents of tyrosine...

  14. Detection of naphthalene by the blue crab, Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, W.H.; Olla, B.L.

    1979-03-01

    Increases in the antennular flicking rate indicated that blue crabs, Callinectes sapidus, detected the petroleum hydrocarbon naphthalene. A low incidence of aggressive displays but no food searching or gathering followed naphthalene detection. The results suggest that the chemosensory abilities of decapod crustaceans cover a broader range of substances than previously supposed.

  15. Diurnal Changes in Angular Sensitivity of Crab Photoreceptors

    NARCIS (Netherlands)

    Leggett, L.M.W.; Stavenga, D.G.

    1981-01-01

    The electrophysiological and anatomical consequences of diurnal changes in screening pigment position were investigated in the apposition eye of the portunid crab Scylla serrata. Intracellular recordings revealed that the acceptance angles of dark-adapted photoreceptors enlarged up to four-fold at n

  16. Diurnal Changes in Angular Sensitivity of Crab Photoreceptors

    NARCIS (Netherlands)

    Leggett, L.M.W.; Stavenga, D.G.

    1981-01-01

    The electrophysiological and anatomical consequences of diurnal changes in screening pigment position were investigated in the apposition eye of the portunid crab Scylla serrata. Intracellular recordings revealed that the acceptance angles of dark-adapted photoreceptors enlarged up to four-fold at

  17. Three-Dimensional Concentration Measurements around Actively Tracking Blue Crabs

    Science.gov (United States)

    Dickman, B. D.; Jackson, J. L.; Weissburg, M. J.; Webster, D. R.

    2006-11-01

    Many aquatic arthropods locate food, suitable habitats, and mates solely through information extracted by chemical signals in their environment. Chemical plumes detected by larger animals are influenced by turbulence that creates an intermittent and unpredictable chemical stimulus environment. To link the stimulus pattern to behavior, we have developed a measurement system to quantify the instantaneous odor concentration surrounding a freely tracking blue crab through three-dimensional laser-induced fluorescence (3DLIF). A blue crab receives chemical stimulus at several locations, including the antennules near the mouth region and the distal tips of the legs and claws. Hence, three-dimensional measurements of the concentration field are required to link behavior to plume structure. During trials, crabs began their search 150 cm downstream of a source, and walking kinematics were recording simultaneously. The crabs were reversibly ``blindfolded'' during tracking to prevent aversive reactions to the intense laser light. Our experiments allow us to examine how hypothesized navigational cues, such as concentration bursts at the antennules and spatial asymmetry in concentration at the distributed chemosensory organs on the legs and claws, results in particular decisions during navigation.

  18. Seasonal variability of antioxidant biomarkers in mud crabs (Scylla serrata).

    Science.gov (United States)

    Paital, Biswaranjan; Chainy, G B N

    2013-01-01

    Studies on oxidative stress (OS) in crustacea are widely used as ecotoxicological indices to assess the environment risk produced by the impact of several stressor and pollutants. In the present study, effects of seasonality on OS physiology markers such as antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase), small antioxidant molecules (ascorbic acid and reduced glutathione), oxidative stress indices (lipid peroxidation, protein carbonylation and hydrogen peroxide) and total antioxidant capacity in hepatopancreas, gills and abdominal muscle of adult mud crab Scylla serrata, sampled from Chilika lagoon of India, were determined in winter, summer and rainy seasons. Results indicate that variations in enzymatic and non-enzymatic antioxidants with relation to season were not only tissue specific but also were gender specific. The levels of OS parameters were higher in hepatopancreas in comparison to gills and abdominal muscle of the crabs in all seasons. OS indices in tissues of the crabs were mainly higher in summer season when temperature and salinity of the lagoon were high with low oxygen content. Although OS was lower in winter season and moderate in rainy season in tissues of male crabs, it was higher in gills and hepatopancreas of females in rainy season. Correlation analyses between hydrological parameters of the lagoon (temperature, salinity and dissolved oxygen content) and OS physiology parameters in tissues of crabs suggest that abiotic factors influence the levels of antioxidant enzymes and, thereby the OS status in a tissue and sex specific manner. Collectively, the results of the present work suggest that further investigation is warranted before using OS parameters in S. serrata as biomarkers to monitor estuarine environment as these are influenced by gender, tissue and season.

  19. Spatial and temporal patterns of subtidal and intertidal crabs excursions

    Science.gov (United States)

    Silva, A. C. F.; Boaventura, D. M.; Thompson, R. C.; Hawkins, S. J.

    2014-01-01

    Highly mobile predators such as fish and crabs are known to migrate from the subtidal zone to forage in the intertidal zone at high-tide. The extent and variation of these habitat linking movements along the vertical shore gradient have not been examined before for several species simultaneously, hence not accounting for species interactions. Here, the foraging excursions of Carcinus maenas (L.), Necora puber (Linnaeus, 1767) and Cancer pagurus (Linnaeus, 1758) were assessed in a one-year mark-recapture study on two replicated rocky shores in southwest U.K. A comparison between the abundance of individuals present on the shore at high-tide with those present in refuges exposed at low-tide indicated considerable intertidal migration by all species, showing strong linkage between subtidal and intertidal habitats. Estimates of population size based on recapture of marked individuals indicated that an average of ~ 4000 individuals combined for the three crab species, can be present on the shore during one tidal cycle. There was also a high fidelity of individuals and species to particular shore levels. Underlying mechanisms for these spatial patterns such as prey availability and agonistic interactions are discussed. Survival rates were estimated using the Cormack-Jolly-Seber model from multi-recapture analysis and found to be considerably high with a minimum of 30% for all species. Growth rates were found to vary intraspecifically with size and between seasons. Understanding the temporal and spatial variations in predation pressure by crabs on rocky shores is dependent on knowing who, when and how many of these commercially important crab species depend on intertidal foraging. Previous studies have shown that the diet of these species is strongly based on intertidal prey including key species such as limpets; hence intertidal crab migration could be associated with considerable impacts on intertidal assemblages.

  20. Incidence of bacteremia in stressed and unstressed populations of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Welsh, P C; Sizemore, R K

    1985-01-01

    The incidence of bacteremia in the blue crab, Callinectes sapidus, is reported to be in excess of 80%. Because these results have been controversial, a field study was initiated to determine the effect of commercial capture and handling stresses on the incidence and levels of infection in blue crabs. The majority (75%) of "unstressed" crabs which were captured individually and bled immediately upon removal from the water were bacteremic, with a geometric mean level of infection of 14 CFU/ml of hemolymph. Crabs collected by crab pot, confined within these pots for as long as 24 h, and sampled immediately after removal from the water had a similar mean level of infection. Crabs subjected to the stresses of commercial capture, handling, and transport showed a higher incidence of infection (91%) and a mean infection level of 46 CFU/ml. Injuries sustained by crabs during commercial handling are thought to be associated with the higher incidence of infection. Vibrio spp. were primarily responsible for progressive infections in commercially stressed crabs and were the predominant bacterial type in heavily infected crabs. Our results indicated that uninjured healthy crabs do not have sterile hemolymph but instead harbor low-level bacterial infections. PMID:4051486

  1. Estimated Entrainment of Dungeness Crab During Dredging For The Columbia River Channel Improvement Project

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Walter H.; Williams, Greg D.; Skalski, John R.

    2002-12-01

    The studies reported here focus on issues regarding the entrainment of Dungeness crab related to the proposed Columbia River Channel Improvement Project and provided direct measurements of crab entrainment rates at three locations (Desdomona Shoals, Upper Sands, and Miller Sands) from RM4 to RM24 during summer 2002. Entrainment rates for all age classes of crabs ranged from zero at Miller Sands to 0.224 crabs per cy at Desdemona Shoals in June 2002. The overall entrainment rate at Desdomona Shoals in September was 0.120 crabs per cy. A modified Dredge Impact Model (DIM) used the summer 2002 entrainment rates to project crab entrainment and adult equivalent loss and loss to the fishery for the Channel Improvement Project. To improve the projections, entrainment data from Flavel Bar is needed. The literature, analyses of salinity intrusion scenarios, and the summer 2002 site-specific data on entrainment and salinity all indicate that bottom salinity influences crab distribution and entrainment, especially at lower salinities. It is now clear from field measurements of entrainment rates and salinity during a period of low river flow (90-150 Kcfs) and high salinity intrusion that entrainment rates are zero where bottom salinity is less than 16 o/oo most of the time. Further, entrainment rates of 2+ and older crab fall with decreasing salinity in a clear and consistent manner. More elaboration of the crab distribution- salinity model, especially concerning salinity and the movements of 1+ crab, is needed.

  2. Black yeast-like fungi associated with Lethargic Crab Disease (LCD) in the mangrove-land crab, Ucides cordatus (Ocypodidae).

    Science.gov (United States)

    Vicente, Vania A; Orélis-Ribeiro, R; Najafzadeh, M J; Sun, Jiufeng; Guerra, Raquel Schier; Miesch, Stephanie; Ostrensky, Antonio; Meis, Jacques F; Klaassen, Corné H; de Hoog, G S; Boeger, Walter A

    2012-07-06

    Lethargic Crab Disease (LCD) caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Brachyura: Ocypodidae) along the Brazilian coast, mainly in the Northeastern region. The disease was named after the symptoms of slow movement of infected crabs. Causative agents were suspected to be two black yeast-like fungi of the family Herpotrichiellaceae (ascomycete order Chaetothyriales), judged by infected tissue biopsies from moribund U. cordatus. The aim of the present study is to prove that two species are involved in the disease: the recently described black yeast Exophiala cancerae, but also a less virulent, hitherto undescribed fonsecaea-like species, introduced here as the novel species Fonsecaea brasiliensis. Strains were identified by ITS rDNA sequencing, and species borderlines were established by multilocus sequencing and AFLP analysis. Fonsecaea brasiliensis proved to be closely related to the pathogenic species Cladophialophora devriesii which originally was isolated from a systemic infection in a human patient. The virulence of F. brasiliensis is lower than that of E. cancerae, as established by artificial inoculation of mangrove crabs.

  3. Comparative brain architecture of the European shore crab Carcinus maenas (Brachyura) and the common hermit crab Pagurus bernhardus (Anomura) with notes on other marine hermit crabs.

    Science.gov (United States)

    Krieger, Jakob; Sombke, Andy; Seefluth, Florian; Kenning, Matthes; Hansson, Bill S; Harzsch, Steffen

    2012-04-01

    The European shore crab Carcinus maenas and the common hermit crab Pagurus bernhardus are members of the sister taxa Brachyura and Anomura (together forming the taxon Meiura) respectively. Both species share similar coastal marine habitats and thus are confronted with similar environmental conditions. This study sets out to explore variations of general brain architecture of species that live in seemingly similar habitats but belong to different major malacostracan taxa and to understand possible differences of sensory systems and related brain compartments. We examined the brains of Carcinus maenas, Pagurus bernhardus, and three other hermit crab species with immunohistochemistry against tyrosinated tubulin, f-actin, synaptic proteins, RF-amides and allatostatin. Our comparison showed that their optic neuropils within the eyestalks display strong resemblance in gross morphology as well as in detailed organization, suggesting a rather similar potential of processing visual input. Besides the well-developed visual system, the olfactory neuropils are distinct components in the brain of both C. maenas and P. bernhardus as well as the other hermit crabs, suggesting that close integration of olfactory and visual information may be useful in turbid marine environments with low visibility, as is typical for many habitats such as, e.g., the Baltic and the North Sea. Comparing the shape of the olfactory glomeruli in the anomurans showed some variations, ranging from a wedge shape to an elongate morphology. Furthermore, the tritocerebrum and the organization of the second antennae associated with the tritocerebrum seem to differ markedly in C. maenas and P. bernhardus, indicating better mechanosensory abilities in the latter close to those of other Decapoda with long second antennae, such as Astacida, Homarida, or Achelata. This aspect may also represent an adaptation to the "hermit lifestyle" in which competition for shells is a major aspect of their life history. The shore

  4. CRABS IN CRISIS:BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND VULNERABILITIES TO CLIMATE CHANGE OF BRACHYURAN AND LITHODID CRABS FROM THE GULF OF CALIFORNIA TO THE BEAUFORT SEA

    Science.gov (United States)

    To predict the relative vulnerability of near-coastal species to climate change we analyzed the biogeographic and abundance patterns of the brachyuran or ‘True’ crabs (n=368) and lithodid or ‘King’ crabs (n=20) that are found in the twelve MEOW (“Mar...

  5. CRABS IN CRISIS:BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND VULNERABILITIES TO CLIMATE CHANGE OF BRACHYURAN AND LITHODID CRABS FROM THE GULF OF CALIFORNIA TO THE BEAUFORT SEA

    Science.gov (United States)

    To predict the relative vulnerability of near-coastal species to climate change we analyzed the biogeographic and abundance patterns of the brachyuran or ‘True’ crabs (n=368) and lithodid or ‘King’ crabs (n=20) that are found in the twelve MEOW (“Mar...

  6. Heavy metals in red crabs, Chaceon quinquedens, from the Gulf of Mexico.

    Science.gov (United States)

    Perry, Harriet; Isphording, Wayne; Trigg, Christine; Riedel, Ralf

    2015-12-30

    The red crab, Chaceon quinquedens, is distributed in deep waters of the Gulf of Mexico (GOM) and is most abundant in an area associated with sediment deposition from the Mississippi River. Sediment geochemistry and biological and ecological traits of red crabs favor accumulation of contaminants. Red crabs, sediment, and bottom water samples were taken from three distinct geographic locations representing areas with differing exposure to contaminant laden effluents from the Mississippi River. Inductively coupled plasma spectrophotometry and atomic absorption spectrophotometry were employed to determine levels of heavy metals in red crab muscle tissue. Ion site partitioning was used to determine metal speciation in sediments. Red crabs showed evidence of heavy metal bioaccumulation in all sample areas with high variability in contaminant levels in individual crabs for some metals. Bioavailability of metals in sediment did not always result in accumulation in muscle tissue.

  7. Disease, parasite, and commensal prevalences for blue crab Callinectes sapidus at shedding facilities in Louisiana, USA.

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Schott, Eric J; Anderson Lively, Julie A

    2015-01-15

    Blue crab diseases, parasites, and commensals are not well studied in the Gulf of Mexico, and their prevalence rates have only been sporadically determined. Commercial soft shell shedding facilities in Louisiana experience high mortality rates of pre-molt crabs, and some of these deaths may be attributable to diseases or parasites. During the active shedding season in 2013, we determined the prevalence of shell disease, Vibrio spp., Lagenophrys callinectes, and Hematodinium perezi at 4 commercial shedding facilities along the Louisiana coast. We also detected Ameson michaelis and reo-like virus infections. Shell disease was moderately prevalent at rates above 50% and varied by shedding facility, collection month, and crab size. Vibrio spp. bacteria were prevalent in the hemolymph of 37% of the pre-molt crabs. Lagenophrys callinectes was highly prevalent in the pre-molt crabs, but because it is a commensal species, it may not cause high mortality rates. Hematodinium perezi was absent in all pre-molt crabs.

  8. Toxicity of the dispersant Corexit 9500 to early life stages of blue crab, Callinectes sapidus.

    Science.gov (United States)

    Anderson Lively, Julie A; McKenzie, Jon

    2014-12-01

    The Deepwater Horizon well released 4.4 million barrels of light crude oil offshore of Louisiana into one of the world's largest and most productive blue crab (Callinectes sapidus) fisheries. The objectives of this paper were to determine the toxicity of the dispersant Corexit(®) 9500A used in the 2010 oil spill on juvenile and larval blue crabs, and the long-term effects of sublethal acute exposure. Only the highest treatment levels of dispersant significantly increased mortality in larval and juvenile blue crabs (100 mg/L and 1,000 mg/L, respectively). This correlated to concentrations well above levels found in the Gulf of Mexico following the spill. Smaller and younger crabs showed higher mortality than older and larger crabs. This research indicates direct application of dispersants on crab larvae could cause acute mortality, but dilution through diffusion and natural weathering processes would minimize long-term effects.

  9. Shell use and partitioning of two sympatric species of hermit crabs on a tropical mudflat

    Science.gov (United States)

    Teoh, Hong Wooi; Chong, Ving Ching

    2014-02-01

    Shell use and partitioning of two sympatric hermit crab species (Diogenes moosai and Diogenes lopochir), as determined by shell shape, size and availability, were examined from August 2009 to March 2011 in a tropical mudflat (Malaysia). Shells of 14 gastropod species were used but > 85% comprised shells of Cerithidea cingulata, Nassarius cf. olivaceus, Nassarius jacksonianus, and Thais malayensis. Shell partitioning between hermit crab species, sexes, and developmental stages was evident from occupied shells of different species, shapes, and sizes. Extreme bias in shell use pattern by male and female of both species of hermit crabs suggests that shell shape, which depends on shell species, is the major determinant of shell use. The hermit crab must however fit well into the shell so that compatibility between crab size and shell size becomes crucial. Although shell availability possibly influenced shell use and hermit crab distribution, this is not critical in a tropical setting of high gastropod diversity and abundance.

  10. Crab dispersion and its impact on the CERN Large Hadron Collider collimation

    CERN Document Server

    Sun, P; Tomàs, R; Zimmermann, F

    2010-01-01

    Crab cavities are proposed to be used for a luminosity upgrade of the Large Hadron Collider (LHC). Crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The crab cavity introduces another kind of dispersion to the particles which is z dependent, and thus could complicate the beam dynamics and have an impact on the LHC collimation system. As for LHC, the off-momentum beta-beat and dispersion-beat already compromise the performance of the collimation system; the crab dispersion introduced by global crab cavities might do the same, and should be carefully evaluated. In this paper, we present a definition for the crab dispersion, and study its impact on the LHC collimation system.

  11. Observations of a Series of Six Recent Glitches in the Crab Pulsar

    CERN Document Server

    Wong, T; Lyne, A G; Wong, Tony

    2001-01-01

    From 1995 to 1999, daily monitoring of the radio emission from the Crab pulsar at the Green Bank and Jodrell Bank observatories revealed a series of six sudden rotational spinups or glitches, doubling the number of glitches observed for this pulsar since 1969. With these observations, the range of time intervals between significant Crab glitches has widened considerably, indicating that the occurrence of Crab glitches may be more random than previously thought. The new glitch amplitudes ($\\Delta\

  12. A summary of the dungeness crab research program 1974-1980

    OpenAIRE

    1981-01-01

    In 1974, the State Legislature directed the Department of Fish and Game to investigate causes of a long-term decline in Dungeness crab, Cancer magister, commercial fishery landings in central California. The Department established the Dungeness Crab Research Program which conducted investigations on crab life history, pollution, and oceanography. Genetic studies to determine if there were different stocks along the coast were inconclusive. Early larval stages (zoeae) drifted progressive...

  13. Evaluation of parenteral drugs for anesthesia in the blue crab (Callinectes sapidus).

    Science.gov (United States)

    Quesada, Rolando J; Smith, Christopher D; Heard, Darryl J

    2011-06-01

    The objective of this study was to evaluate the efficacy and safety of several parenteral anesthetics in blue crabs (Callinectes sapidus). Thirty-one animals were administered one or more of the following drugs by injection into the hemolymph (i.v.) through an arthrodial membrane: etomidate, ketamine, lidocaine, pentobarbital, propofol, tiletamine-zolazepam, xylazine, and ketamine-xylazine. A subset of crabs received intracardiac ketamine. Etomidate had no effect. Lidocaine effects were ultrashort (sapidus as well as in other crab species.

  14. Metals in crab, oyster and sediment in two South Carolina estuaries

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-01

    The blue crab Callinectes sapidus and the eastern oyster Crassostrea virginica have the ability to concentrate metals from the marine environment. From August 1979 to May 1981, cadmium, copper, lead and zinc concentrations were determined quarterly for crab, oyster, and bottom sediment from two estuarine areas in the vicinity of Charleston, South Carolina. The results of the analyses indicate that crab muscle and oyster meats obtained from locations nearest domestic and industrial activities have the highest Cu and Zn concentrations.

  15. An outbreak of horseshoe crab poisoning in Chon Buri, Thailand: clinical, toxicologic and therapeutic considerations.

    Science.gov (United States)

    Kanchanapongkul, J; Kungsuwan, A; Tantisiriwan, V; Punthawangkun, C; Krittayapoositpot, P

    1996-12-01

    In 1994-1996, an outbreak of horseshoe crab poisoning by eating toxic eggs of the horseshoe crab Carcinoscorpius rotundicauda affected over 100 persons in Chon Buri which located on the eastern coast of Thailand. We discuss clinical description and management of this first major outbreak. The responsible toxin has been partially purified by means of ultrafiltration and high performance liquid chromatography. The horseshoe crab toxin is identified as tetrodotoxin (TTX) and anhydro TTX.

  16. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Dungeness Crab.

    Science.gov (United States)

    1986-08-01

    analyze some of the original data in this report was provided by Washington Sea Grant. vii 1 II ’ 1 . w. Figure 1. Dungeness crab. - DUNGENESS CRAB 5 -4...Lough Poole 1967). After 1 year of growth 1976; Armstrong 1983). beyond hatching, most crabs in Bodega Bay, California, are in their 8th, Juveniles...Stevens 1982). Grays Harbor, while the range is 63-94 After molting, the juveniles are mm in Bodega Bay (Poole 1967; Stevens found in shallow coastal

  17. Spatial patterns and movements of red king and Tanner crabs: Implications for the design of marine protected areas

    Science.gov (United States)

    Taggart, S.J.; Mondragon, J.; Andrews, A.G.; Nielsen, J.K.

    2008-01-01

    Most examples of positive population responses to marine protected areas (MPAs) have been documented for tropical reef species with very small home ranges; the utility of MPAs for commercially harvested temperate species that have large movement patterns remains poorly tested. We measured the distribution and abundance of red king Paralithodes camtschaticus and Tanner Chionoecetes bairdi crabs inside and outside of MPAs in Glacier Bay National Park, Alaska, USA. By tagging a sub-sample of crabs with sonic tags, we estimated the movement of adult crabs from one of the MPAs (Muir Inlet) into the central portion of Glacier Bay where fishing still occurs. Tanner crabs and red king crabs moved similar average distances per day, although Tanner crabs had a higher transfer out of the Muir Inlet MPA into the central bay. Tanner crab movements were characterized by large variation among individual crabs, both in distance and direction traveled, while red king crabs migrated seasonally between 2 specific areas. Although Tanner crabs exhibited relatively large movements, distribution and abundance data suggest that they may be restricted at large spatial scales by habitat barriers. MPAs that are effective at protecting king and especially Tanner crab brood stock from fishing mortality will likely need to be larger than is typical of MPAs worldwide. However, by incorporating information on the seasonal movements of red king crabs and the location of habitat barriers for Tanner crabs, MPAs could likely be designed that would effectively protect adults from fishing mortality. ?? Inter-Research 2008.

  18. Oxygen and carbon dioxide sensitivity of ventilation in amphibious crabs, Cardisoma guanhumi, breathing air and water.

    Science.gov (United States)

    Gannon, Andrew T; Henry, Raymond P

    2004-05-01

    Amphibious crabs, Cardisoma guanhumi, were acclimated to breathing either air or water and exposed to altered levels of oxygen and/or carbon dioxide in the medium. Hypercapnia (22, 36 and 73 torr CO(2)) stimulated a significant hypercapnic ventilatory response (HCVR) in both groups of crabs, with a much greater effect on scaphognathite frequency (Deltaf(SC)=+700%) in air-breathing crabs than water-breathing crabs (Deltaf(SC)=+100%). In contrast, hyperoxia induced significant hypoventilation in both sets of crabs. However, simultaneous hyperoxia and hypercapnia triggered a greater than 10-fold increase in f(SC) in air-breathing crabs but no change in water-breathing crabs. For water-breathing crabs hypoxia simultaneous with hypercapnia triggered the same response as hypoxia alone-bradycardia (-50%), and a significant increase in f(SC) at moderate exposures but not at the more extreme levels. The response of air-breathing crabs to hypoxia concurrent with hypercapnia was proportionally closer to the response to hypercapnia alone than to hypoxia. Thus, C. guanhumi were more sensitive to ambient CO(2) than O(2) when breathing air, characteristic of fully terrestrial species, and more sensitive to ambient O(2) when breathing water, characteristic of fully aquatic species. C. guanhumi possesses both an O(2)- and a CO(2)-based ventilatory drive whether breathing air or water, but the relative importance switches when the respiratory medium is altered.

  19. Edible crabs "go west": migrations and incubation cycle of Cancer pagurus revealed by electronic tags.

    Directory of Open Access Journals (Sweden)

    Ewan Hunter

    Full Text Available Crustaceans are key components of marine ecosystems which, like other exploited marine taxa, show seasonable patterns of distribution and activity, with consequences for their availability to capture by targeted fisheries. Despite concerns over the sustainability of crab fisheries worldwide, difficulties in observing crabs' behaviour over their annual cycles, and the timings and durations of reproduction, remain poorly understood. From the release of 128 mature female edible crabs tagged with electronic data storage tags (DSTs, we demonstrate predominantly westward migration in the English Channel. Eastern Channel crabs migrated further than western Channel crabs, while crabs released outside the Channel showed little or no migration. Individual migrations were punctuated by a 7-month hiatus, when crabs remained stationary, coincident with the main period of crab spawning and egg incubation. Incubation commenced earlier in the west, from late October onwards, and brooding locations, determined using tidal geolocation, occurred throughout the species range. With an overall return rate of 34%, our results demonstrate that previous reluctance to tag crabs with relatively high-cost DSTs for fear of loss following moulting is unfounded, and that DSTs can generate precise information with regards life-history metrics that would be unachievable using other conventional means.

  20. Diet selectivity of juvenile blue crabs (Callinectes sapidus) in Chesapeake Bay.

    Science.gov (United States)

    Seitz, Rochelle D; Knick, Kathleen E; Westphal, Miranda

    2011-10-01

    Shallow coves in Chesapeake Bay have abundant food and serve as nursery grounds for juvenile blue crabs. In this study, we examined the relationships between the diet of very small (4-40 mm CW) juvenile blue crabs and the benthic infauna in shallow, unvegetated nursery coves. We compared infauna in benthic samples with gut contents of juvenile blue crabs from six shallow coves in each of two sub-estuaries (Rappahannock and York Rivers) in Chesapeake Bay, Virginia, USA. Benthic communities differed depending on river and location, with abundant clams in upriver regions and abundant polychaetes in downriver regions. Juvenile crabs, like adults, appeared to be opportunistic feeders, with gut contents including clams, amphipods, polychaetes, small crustaceans, plant matter, and detritus. There was a positive relationship between polychaetes in the benthic samples and in crab guts, suggesting that juvenile crabs are opportunistic feeders on polychaetes in the benthos. Moreover, Ivlev's electivity index and foraging ratio showed that clams and polychaetes were selectively eaten at all locations. Alternatively, crabs selectively rejected amphipods. Crab densities corresponded positively with polychaete densities, which suggests that there may be bottom-up control of crab distributions and that food resources are important in nursery habitats.

  1. Purification and characterization of a cadmium-induced metallothionein from the shore crab Carcinus maenas (L.)

    DEFF Research Database (Denmark)

    Pedersen, K L; Pedersen, S N; Højrup, P;

    1994-01-01

    Two metallothionein variants were purified from the midgut gland of crabs (Carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). One of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). The purification method involved acetone precipitation...... from crabs exposed to the high cadmium concentration differed only by a single residue of methionine at the N-terminus. The single variant isolated from crabs exposed to the low cadmium concentration was the one without the N-terminal methionine, indicating that high cadmium concentrations either...

  2. The effect of salinity on experimental infections of a Hematodinium sp. in blue crabs, Callinectes sapidus.

    Science.gov (United States)

    Coffey, Anna H; Li, Caiwen; Shields, Jeffrey D

    2012-06-01

    The parasitic dinoflagellate Hematodinium sp. parasitizes blue crabs along the Atlantic seaboard of the United States. Infections in blue crabs have only been reported from waters where salinity is >11 practical salinity units (psu). Blue crabs maintain a hyperosmotic internal concentration at low salinities (0-5 psu), roughly comparable to 24 psu, and should be capable of maintaining an infection in low-salinity waters even if Hematodinium spp. cells are intolerant of low salinities. We tested this notion by observing the effect of low salinity on the progression of disease in crabs experimentally infected with the parasite. Blue crabs were acclimated to 5 psu or 30 psu salinity treatments. They were inoculated with Hematodinium sp. and necropsied 3, 7, 10, and 15 days post-inoculation. The low-salinity treatment did not have an effect on the proliferation of Hematodinium sp. infections in blue crabs; moreover, a greater proportion of infections in crabs in the low-salinity treatment developed dinospore stages than did those in the high-salinity treatment, indicating that salinity may affect the development of the parasite. However, dinospores from in vitro cultures rapidly became inactive when held in salinities crabs at low salinities, but that the parasite is incapable of transmission in this environment, which explains the lack of natural infections in crabs at low salinities.

  3. Edible crabs "go west": migrations and incubation cycle of Cancer pagurus revealed by electronic tags.

    Science.gov (United States)

    Hunter, Ewan; Eaton, Derek; Stewart, Christie; Lawler, Andrew; Smith, Michael T

    2013-01-01

    Crustaceans are key components of marine ecosystems which, like other exploited marine taxa, show seasonable patterns of distribution and activity, with consequences for their availability to capture by targeted fisheries. Despite concerns over the sustainability of crab fisheries worldwide, difficulties in observing crabs' behaviour over their annual cycles, and the timings and durations of reproduction, remain poorly understood. From the release of 128 mature female edible crabs tagged with electronic data storage tags (DSTs), we demonstrate predominantly westward migration in the English Channel. Eastern Channel crabs migrated further than western Channel crabs, while crabs released outside the Channel showed little or no migration. Individual migrations were punctuated by a 7-month hiatus, when crabs remained stationary, coincident with the main period of crab spawning and egg incubation. Incubation commenced earlier in the west, from late October onwards, and brooding locations, determined using tidal geolocation, occurred throughout the species range. With an overall return rate of 34%, our results demonstrate that previous reluctance to tag crabs with relatively high-cost DSTs for fear of loss following moulting is unfounded, and that DSTs can generate precise information with regards life-history metrics that would be unachievable using other conventional means.

  4. Crabs mediate interactions between native and invasive salt marsh plants: a mesocosm study.

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Zhang

    Full Text Available Soil disturbance has been widely recognized as an important factor influencing the structure and dynamics of plant communities. Although soil reworkers were shown to increase habitat complexity and raise the risk of plant invasion, their role in regulating the interactions between native and invasive species remains unclear. We proposed that crab activities, via improving soil nitrogen availability, may indirectly affect the interactions between invasive Spartina alterniflora and native Phragmites australis and Scirpus mariqueter in salt marsh ecosystems. We conducted a two-year mesocosm experiment consisting of five species combinations, i.e., monocultures of three species and pair-wise mixtures of invasive and native species, with crabs being either present or absent for each combination. We found that crabs could mitigate soil nitrogen depletion in the mesocosm over the two years. Plant performance of all species, at both the ramet-level (height and biomass per ramet and plot-level (density, total above- and belowground biomass, were promoted by crab activities. These plants responded to crab disturbance primarily by clonal propagation, as plot-level performance was more sensitive to crabs than ramet-level. Moreover, crab activities altered the competition between Spartina and native plants in favor of the former, since Spartina was more promoted than native plants by crab activities. Our results suggested that crab activities may increase the competition ability of Spartina over native Phragmites and Scirpus through alleviating soil nitrogen limitation.

  5. Multipole Field Effects for the Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    Energy Technology Data Exchange (ETDEWEB)

    De Silva, Payagalage Subashini Uddika [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States) and Old Dominion University, Norfolk, VA (United States); Delayen, Jean Roger [Old Dominion University, Norfolk, VA (United States)

    2012-09-01

    The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

  6. Geometric design of crab-like climbing and walking robots

    Institute of Scientific and Technical Information of China (English)

    LIU An-min; David Howard

    2004-01-01

    This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, being particularly well suited to crossing difficult terrains. Firstly, the kinematic configurations and constraints are described, which determine the machine's kinematic characteristics. The influence of the design parameters on the kinematic workspace is discussed. Finally,a two stage design methodology is presented, comprising kinematic design and design optimisation, the latter being based on the use of design maps rather than numerical optimisation. The performance measures considered during design optimisation include kinematic, static and quasi-static measures.

  7. Observations of the Crab pulsar with the MAGIC telescopes

    CERN Document Server

    Saito, T Y; Giavitto, G; Klepser, S; Schweizer, T; Zanin, R

    2011-01-01

    We report on the observations of the Crab pulsar with the MAGIC telesopes. Data were taken both in the mono-mode ($>25$ GeV) and in the stereo-mode ($>50$ GeV). Clear signals from the two peaks were detected with both modes and the phase resolved energy spectra were calculated. By comparing with the measurements done by Fermi-LAT, we found that the energy spectra of the Crab pulsar does not follow a power law with an exponential cutoff, but that it extends as a power law after the break at around 5 GeV. This suggests that the emission above 25 GeV is not dominated by the curvatura radiation, which is inconsistent with the standard prediction of the OG and SG models.

  8. The Crab Pulsar at Centimeter Wavelengths: I. Ensemble Characteristics

    CERN Document Server

    Hankins, T H; Eilek, J A

    2015-01-01

    We have observed the pulsar in the Crab Nebula at high radio frequencies and high time resolution. We present continuously sampled data at 640-ns time resolution, and individual bright pulses recorded at down to 0.25-ns time resolution. Combining our new data with previous data from our group and from the literature shows the dramatic changes in the pulsar's radio emission between low and high radio frequencies. Below about 5 GHz the mean profile is dominated by the bright Main Pulse and Low-Frequency Interpulse. Everything changes, however, above about 5 GHz; the Main Pulse disappears, the mean profile of the Crab pulsar is dominated by the High-Frequency Interpulse (which is quite different from its low-frequency counterpart) and the two High-Frequency Components. We present detailed observational characteristics of these different components which future models of the pulsar's magnetosphere must explain.

  9. THE CRAB PULSAR AT CENTIMETER WAVELENGTHS. I. ENSEMBLE CHARACTERISTICS

    Energy Technology Data Exchange (ETDEWEB)

    Hankins, T. H.; Eilek, J. A., E-mail: thankins@aoc.nrao.edu [Physics Department, New Mexico Tech, Socorro, NM 87801 (United States); Jones, G.

    2015-04-01

    We have observed the pulsar in the Crab Nebula at high radio frequencies and high time resolution. We present continuously sampled data at 640 ns time resolution and individual bright pulses recorded at down to 0.25 ns time resolution. Combining our new data with previous data from our group and from the literature shows the dramatic changes in the pulsar’s radio emission between low and high radio frequencies. Below about 5 GHz the mean profile is dominated by the bright Main Pulse and Low-Frequency Interpulse. Everything changes, however, above about 5 GHz; the Main Pulse disappears and the mean profile of the Crab pulsar is dominated by the High-Frequency Interpulse (which is quite different from its low-frequency counterpart) and the two High-Frequency Components. We present detailed observational characteristics of these different components which future models of the pulsar’s magnetosphere must explain.

  10. Observations of "wisps" in magnetohydrodynamic simulations of the Crab Nebula

    CERN Document Server

    Camus, N F; Buccantini, N; Hughes, P A

    2009-01-01

    In this letter, we describe results of new high-resolution axisymmetric relativistic MHD simulations of Pulsar Wind Nebulae. The simulations reveal strong breakdown of the equatorial symmetry and highly variable structure of the pulsar wind termination shock. The synthetic synchrotron maps, constructed using a new more accurate approach, show striking similarity with the well known images of the Crab Nebula obtained by Chandra, and the Hubble Space Telescope. In addition to the \\textit{jet-torus} structure, these maps reproduce the Crab's famous moving wisps whose speed and rateof production agree with the observations. The variability is then analyzed using various statistical methods, including the method of structure function and wavelet transform. The results point towards the quasi-periodic behaviour with the periods of 1.5-3yr and MHD turbulence on scales below 1yr. The full account of this study will be presented in a follow up paper.

  11. SUPERCONDUCTING RF-DIPOLE DEFLECTING AND CRABBING CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Delayen, Jean [ODU, JLAB; De Silva, Paygalage Subashini [ODU, JLAB

    2013-09-01

    Recent interests in designing compact deflecting and crabbing structures for future accelerators and colliders have initiated the development of novel rf structures. The superconducting rf-dipole cavity is one of the first compact designs with attractive properties such as higher gradients, higher shunt impedance, the absence of lower order modes and widely separated higher order modes. Two rf-dipole designs of 400 MHz and 499 MHz have been designed, fabricated and tested as proof-of-principle designs of compact deflecting and crabbing cavities for the LHC high luminosity upgrade and Jefferson Lab 12 GeV upgrade. The first rf tests have been performed on the rf-dipole geometries at 4.2 K and 2.0 K in a vertical test assembly with excellent results. The cavities have achieved high gradients with high intrinsic quality factors, and multipacting levels were easily processed.

  12. Shell selection of hermit crabs is influenced by fluid drag

    Science.gov (United States)

    Casillas, Barbara; Ledesma, Rene; Alcaraz, Guillermina; Zenit, Roberto

    2010-11-01

    The flow around gastropod shells used by hermit crabs (Calcinus californiensis) was visualized experimentally. These crabs choose their shells according to many factors; we found that the choice of shell (shape and weight) is directly related to the drag caused over them by the exposure to wave action. Tests were conducted in a wind tunnel to investigate flow differences for shells of various shapes. A particle image velocimetry (PIV) system was used to visualize the flow field. The images above show the flow field around two types of shells (Thais speciosa and Nerita scabircosta) for Reynolds numbers of O(10^5). Using a control volume analysis, the drag coefficient was inferred. Several shell geometries, orientations and mean flow velocities were tested. In this talk, the flow and drag force will be shown for the different arrangements. A discussion of the relation between drag and shape will be presented.

  13. Cymonomid crabs of the MAINBAZA Expedition (Decapoda: Brachyura).

    Science.gov (United States)

    Ahyong, Shane T

    2014-06-23

    Cymonomid crabs collected from the Mozambique Channel off Madagascar by the 2011 MAINBAZA Expedition are reported. Two species of Cymonomus A. Milne Edwards, 1880, are represented, of which one is new to science and the other, C. valdiviae Lankester, 1903, is rediscovered, being previously known only from the holotype. Three species of Cymonomidae are now known from the western Indian Ocean, including C. trifurcus Stebbing, 1920, from South Africa. 

  14. Crab Hole Mosquito Blues—The Story

    Centers for Disease Control (CDC) Podcasts

    2011-05-12

    This podcast reports on a humorous song that takes a look at a very serious human and equine disease. Written and performed by the MARU Health Angels Band, Bill Dietz, director of the Division of Nutrition, Physical Activity and Obesity at CDC, talks about the song, "Crab Hole Mosquito Blues", and the history behind it.  Created: 5/12/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 5/23/2011.

  15. Motor Driving Leg Design for Bionic Crab-like Robot

    Institute of Scientific and Technical Information of China (English)

    Wang; Li-quan; Qu; Xiao-rong; Meng; Qing-xin; Yuan; Peng; Wang; Mo-nan

    2002-01-01

    The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, which has been used in the robot design. A three closed loop motor control system structure for joint driver is also given, as well as the multi-joint driving system for walking robot leg.

  16. [Detection of allergenic substances (shrimp, crab) in processed seafood].

    Science.gov (United States)

    Watanabe, Hiroko; Saita, Kiyotaka; Akaboshi, Chie; Ohsawa, Nobuhiko; Hashiguchi, Shigeki; Miyazawa, Maki

    2014-01-01

    We have carried out a study (2009-2012) on processed seafood products in order to determine the level of contamination with shrimp and crab. In 2010-2012, after the Allergy Labeling Regulation went into effect, the detection rate of crustacean protein in processed seafood products including small fish, such as niboshi, tukudani and so on (both boiled and dried), was 63%. Detection rates for processed seafood products in which crustacean protein levels were below 1 μg/g were 36% with and 58% without advisory labels, allowing us to conclude that 60% of labels were adequate. On the other hand, the detection rate for processed seafood products with crustacean protein levels higher than the baseline of 10 μg/g was 9%, of which 60% carried no advisory labels. The rate of shrimp DNA detection using the Akiami primer in processed foods containing shrimp and crab was high (73%). This suggests that it is necessary to test these products using the Akiami primer for supplemental analyses of shrimp DNA. The PCR analysis for crab DNA detection failed due to combined detection of mantis shrimp DNA, which accounted for 8% of the total detected.

  17. Observation and Spectral Measurements of the Crab Nebula with Milagro

    Science.gov (United States)

    Abdo, A. A.; Allen, B. T.; Aune, T.; Benbow, W.; Berley, D.; Chen, C.; Christopher, G. E.; DeYoung, T.; Dingus, B. L.; Falcone, A.; Fleysher, L.; Fleysher, R.; Gonzalez, M. M.; Goodman, J. A.; Gordo, J. B.; Hays, E.; Hoffman, C. M.; Huntemeyer, P. H.; Kolterman, B. E.; Linnemann, J. T.; McEnery, J. E.; Morgan, T.; Mincer, A. I.; Nemethy, P.

    2011-01-01

    The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by observing the particle footprint reaching the ground. The fraction of detectors recording signals from photons at the ground is a suitable proxy for the energy of the primary particle and has been used to measure the photon energy spectrum of the Crab Nebula between 1 and 100 TeV. The TeV emission is believed to be caused by inverse-Compton up-scattering scattering of ambient photons by an energetic electron population. The location of a Te V steepening or cutoff in the energy spectrum reveals important details about the underlying electron population. We describe the experiment and the technique for distinguishing gamma-ray events from the much more-abundant hadronic events. We describe the calculation of the significance of the excess from the Crab and how the energy spectrum is fit.

  18. Observation and Spectral Measurements of the Crab Nebula with Milagro

    CERN Document Server

    Abdo, A A; Aune, T; Benbow, W; Berley, D; Chen, C; Christopher, G E; DeYoung, T; Dingus, B L; Ellsworth, R W; Falcone, A; Fleysher, L; Fleysher, R; Gonzalez, M M; Goodman, J A; Gordo, J B; Hays, E; Hoffman, C M; Huentemeyer, P H; Kolterman, B E; Linnemann, J T; McEnery, J E; Morgan, T; Mincer, A I; Nemethy, P; Pretz, J; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

    2011-01-01

    The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by observing the particle footprint reaching the ground. The fraction of detectors recording signals from photons at the ground is a suitable proxy for the energy of the primary particle and has been used to measure the photon energy spectrum of the Crab Nebula between ~1 and ~100 TeV. The TeV emission is believed to be caused by inverse-Compton up-scattering scattering of ambient photons by an energetic electron population. The location of a TeV steepening or cutoff in the energy spectrum reveals important details about the underlying electron population. We describe the experiment and the technique for distinguishing gamma-ray events from the much more-abundant hadronic events. We describe the calculation of the significance of the excess from the Crab and how the energy spec...

  19. Differential escape from parasites by two competing introduced crabs

    Science.gov (United States)

    Blakeslee, April M.; Keogh, Carolyn L.; Byers, James E.; Kuris, Armand M.; Lafferty, Kevin D.; Torchin, Mark E.

    2009-01-01

    Although introduced species often interact with one another in their novel communities, the role of parasites in these interactions remains less clear. We examined parasite richness and prevalence in 2 shorecrab species with different invasion histories and residency times in an introduced region where their distributions overlap broadly. On the northeastern coast of the USA, the Asian shorecrab Hemigrapsus sanguineus was discovered 20 yr ago, while the European green crab Carcinus maenas has been established for over 200 yr. We used literature and field surveys to evaluate parasitism in both crabs in their native and introduced ranges. We found only 1 parasite species infecting H. sanguineus on the US East Coast compared to 6 species in its native range, while C. maenas was host to 3 parasite species on the East Coast compared to 10 in its native range. The prevalence of parasite infection was also lower for both crabs in the introduced range compared to their native ranges; however, the difference was almost twice as much for H. sanguineus as for C. maenas. There are several explanations that could contribute to C. maenas' greater parasite diversity than that of H. sanguineus on the US East Coast, including differences in susceptibility, time since introduction, manner of introduction (vector), distance from native range, taxonomic isolation, and the potential for parasite identification bias. Our study underscores not just that non-native species lose parasites upon introduction, but that they may do so differentially, with ramifications for their direct interactions and with potential community-level influences.

  20. Use of blue crab (Callinectes sapidus) embryos for toxicity testing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.; O`Malley, K. [Skidaway Inst. of Oceanography, Savannah, GA (United States)

    1995-12-31

    After fertilization, blue crab embryos develop in egg sacs attached to the female pleopods, often referred to as the sponge. Lipovitellin and lipid droplets in the egg sacs provide energy and nutrition for the developing embryos. Embryos were removed from the sponge and transferred to 24 well culture plates containing sea water with or without toxicants, Each well contained 10 embryos. After 7 to 10 days, embryos hatched to swimming zoea. The effects of toxicants at various concentrations on hatching were determined and the EC{sub 50} calculated. For example, the EC{sub 50} for tributyltin, fenvalerate and mercuric chloride were 50, 30 and 90 ng/liter, respectively. The hatching success of control embryos ranged from 95 to 98%. Formation of the heart, eyespot formation, appendage formation and utilization rate of lipovitellin were also effected by exposure to toxicants. At a low concentration of mercuric ion (30ng/liter) the heart formed, but there was no heart beat. Eyespot formation was abnormal in the presence of high concentrations of cadmium (2 {micro}g/liter) and zinc (5 {micro}g/liter), Crab embryos offer many advantages for toxicity testing of pure compounds or mixtures in water, including toxicity testing of sediment pore water. The crab embryos may also serve as models to understand the effect of specific toxicants on the heart and eye spots of crustaceans.

  1. Chandra Phase-Resolved Spectroscopy of the Crab Pulsar

    CERN Document Server

    Weisskopf, M C; Paerels, F; Becker, W; Tennant, A F; Swartz, D A; Weisskopf, Martin C.; Dell, Stephen L. O'; Paerels, Frits; Becker, Werner; Tennant, Allyn F.; Swartz, Douglas A.

    2004-01-01

    We present the first phase-resolved study of the X-ray spectral properties of the Crab Pulsar that covers all pulse phases. The superb angular resolution of the Chandra X-ray Observatory enables distinguishing the pulsar from the surrounding nebulosity, even at pulse minimum. Analysis of the pulse-averaged spectrum measures interstellar X-ray extinction due primarily to photoelectric absorption and secondarily to scattering by dust grains in the direction of the Crab Nebula. We confirm previous findings that the line-of-sight to the Crab is underabundant in oxygen, although more-so than recently measured. Using the abundances and cross sections from Wilms, Allen & McCray (2000) we find [O/H] = (3.33 +/-0.25) x 10**-4. Analysis of the spectrum as a function of pulse phase measures the low-energy X-ray spectral index even at pulse minimum -- albeit with large statistical uncertainty -- and we find marginal evidence for variations of the spectral index. The data are also used to set a new (3-sigma) upper lim...

  2. Teraelectronvolt pulsed emission from the Crab pulsar detected by MAGIC

    CERN Document Server

    Ahnen, M L; Antonelli, L A; Antoranz, P; Babic, A; Banerjee, B; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Buson, S; Carmona, E; Carosi, A; Chatterjee, A; Clavero, R; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Di Pierro, F; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Glawion, D Eisenacher; Elsaesser, D; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giammaria, P; Godinović, N; Muñoz, A González; Gora, D; Guberman, D; Hadasch, D; Hahn, A; Hanabata, Y; Hayashida, M; Herrera, J; Hose, J; Hrupec, D; Hughes, G; Idec, W; Kodani, K; Konno, Y; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; Lorenz, E; Majumdar, P; Makariev, M; Mallot, K; Maneva, G; Manganaro, M; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Moretti, E; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palacio, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Pedaletti, G; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Saito, T; Satalecka, K; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Steinbring, T; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Torres, D F; Toyama, T; Treves, A; Verguilov, V; Vovk, I; Ward, J E; Will, M; Wu, M H; Zanin, R

    2015-01-01

    Aims: To investigate the extension of the very-high-energy spectral tail of the Crab pulsar at energies above 400 GeV. Methods: We analyzed $\\sim$320 hours of good quality data of Crab with the MAGIC telescope, obtained from February 2007 until April 2014. Results: We report the most energetic pulsed emission ever detected from the Crab pulsar reaching up to 1.5 TeV. The pulse profile shows two narrow peaks synchronized with the ones measured in the GeV energy range. The spectra of the two peaks follow two different power-law functions from 70 GeV up to 1.5 TeV and connect smoothly with the spectra measured above 10 GeV by the Large Area Telescope (LAT) on board of the Fermi satellite. When making a joint fit of the LAT and MAGIC data, above 10 GeV, the photon indices of the spectra differ by 0.5$\\pm$0.1. Conclusions: We measured with the MAGIC telescopes the most energetic pulsed photons from a pulsar to date. Such TeV pulsed photons require a parent population of electrons with a Lorentz factor of at least ...

  3. 77 FR 58624 - Progressive Rail Incorporated-Acquisition and Operation Exemption-Rail Lines of Crab Orchard...

    Science.gov (United States)

    2012-09-21

    ... Lines of Crab Orchard & Egyptian Railroad Company Progressive Rail Incorporated (PGR), a Class III rail carrier, has filed a verified notice of exemption under 49 CFR 1150.41 to acquire from Crab Orchard...

  4. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were...

  5. Examination of the available catch and production data to determine if fishing curtailments will provide better crab utilization

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Deals with the Bering Sea King crab industry. Discusses size of crabs, fishing gear, fishing localities, seasons, molting, and production techniques.

  6. a Surprise from the Pulsar in the Crab Nebula

    Science.gov (United States)

    1995-11-01

    New observations of the spectrum of the rapidly spinning neutron star (the `pulsar') in the Crab Nebula have been carried out with the ESO 3.5-metre New Technology Telescope (NTT) by a group of Italian astronomers [1]. Because of greatly improved spectral resolution which allows to register even very fine details in the pulsar's spectrum, they are able to determine for the first time with high accuracy the overall dependance of the emission on wavelength, i.e. the `shape' of the spectrum. Quite unexpectedly, they also detect a hitherto unknown 100 A (10 nm) broad `absorption dip', which can be securely attributed to the pulsar. These results open an exciting new window for the study of the extreme physical processes close to a pulsar. The Nature of Pulsars It is estimated that there may be as many as 100 million neutron stars in our Galaxy. A neutron star is the superdense remnant of the extremely violent supernova explosion that occurs at the end of the life of a comparatively massive star. In fact, all stars that are more than about 6 times heavier than the Sun are believed to end their lives as supernovae. During the explosion, the central core of the dying star collapses in a few milliseconds and the matter at the centre is compressed to a density comparable to that of an atomic nucleus. Due to the enormous inward pressure, the atomic particles are squeezed together into a kind of neutron jam. The outcome is the formation of a neutron star with a diameter of 10-15 kilometres, weighing as much as the Sun. In accordance with the physical law that implies that the rotation momentum of the exploding star must be conserved, newborn neutron stars will rotate very rapidly around their axis, in some cases as fast as 100 times per second. In the same way, the new neutron star is expected to possess a strong magnetic field. Of these myriads of neutron stars, about 700 have been observed to emit radio pulses (hence the name `pulsar'). A few of these can also be detected

  7. Identification of tropomyosin and arginine kinase as major allergens of Portunus pelagicus (blue swimming crab).

    Science.gov (United States)

    Rosmilah, M; Shahnaz, M; Zailatul, H M Y; Noormalin, A; Normilah, I

    2012-09-01

    Crab is an important source of food allergen. Tropomyosin represents the main crab allergen and is responsible for IgE cross-reactivity between various species of crustaceans. Recently, other new crab allergens including arginine kinase have been identified. However, information on allergens of the local Portunidcrab is not available. Thus, the aim of this study was to identify the major allergens of Portunus pelagicus (blue swimming crab) using the allergenomics approach. Raw and cooked extracts of the crab were prepared from the crab meat. Protein profile and IgE binding pattern were demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from 30 patients with crab allergy. The major allergens of the crab were then identified by two-dimensional electrophoresis (2-DE), followed by mass spectrometry analysis of the peptide digests. The SDS-PAGE of raw extract revealed approximately 20 protein fractions over a wide molecular weight range, while cooked extract demonstrated fewer protein bands. The raw extract also demonstrated a higher number of IgE reactive bands than the cooked extract. A heat-resistant protein of 36 kDa has been identified as the major allergen in both raw and cooked extracts. In addition, a heat-sensitive protein of 41 kDa was also recognized as a major allergen in raw crab. The 2-DE gel profile of the raw extract demonstrated about >100 distinct proteins spots and immunoblotting of the 2-DE profile demonstrated at least 12 different major IgE reactive spots with molecular masses between 13 to 250 kDa and isoelectric point (pI) values ranging from 4.0 to 7.0. The 36 and 41 kDa proteins were identified as the crab tropomyosin and arginine kinase, respectively by mass spectrometry. Therefore, this study confirmed that tropomyosin and arginine kinase are the major allergens of the local Portunid crab, P. pelagicus.

  8. (1)H NMR metabolomic profiling of the blue crab (Callinectes sapidus) from the Adriatic Sea (SE Italy): A comparison with warty crab (Eriphia verrucosa), and edible crab (Cancer pagurus).

    Science.gov (United States)

    Zotti, Maurizio; De Pascali, Sandra Angelica; Del Coco, Laura; Migoni, Danilo; Carrozzo, Leonardo; Mancinelli, Giorgio; Fanizzi, Francesco Paolo

    2016-04-01

    The metabolomic profile of blue crab (Callinectes sapidus) captured in the Acquatina lagoon (SE Italy) was compared to an autochthonous (Eriphia verrucosa) and to a commercial crab species (Cancer pagurus). Both lipid and aqueous extracts of raw claw muscle were analyzed by (1)H NMR spectroscopy and MVA (multivariate data analysis). Aqueous extracts were characterized by a higher inter-specific discriminating power compared to lipid fractions. Specifically, higher levels of glutamate, alanine and glycine characterized the aqueous extract of C. sapidus, while homarine, lactate, betaine and taurine characterized E. verrucosa and C. pagurus. On the other hand, only the signals of monounsaturated fatty acids distinguished the lipid profiles of the three crab species. These results support the commercial exploitation and the integration of the blue crab in human diet of European countries as an healthy and valuable seafood. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Locomotion, respiratory physiology, and energetics of amphibious and terrestrial crabs.

    Science.gov (United States)

    Adamczewska, A M; Morris, S

    2000-01-01

    The transition from breathing air to breathing water requires physiological and morphological adaptations. The study of crustaceans in transitional habitats provides important information as to the nature of these adaptations. This article addresses the physiology of air breathing in amphibious and terrestrial crabs and their relative locomotor abilities. Potamonautes warreni is an apparently amphibious freshwater crab from southern Africa, Cardisoma hirtipes is an air-breathing gecarcinid crab with some dependency on freshwater, and Gecarcoidea natalis is an obligate air-breathing gecarcinid endemic to Christmas Island in the Indian Ocean. All three species have well-developed lungs but retain gills and show seasonally different activity patterns that, in the gercarcinids, especially G. natalis, include long-distance breeding migrations. The three species were better at breathing air than water, but P. warreni was the best at breathing water. Cardisoma hirtipes is essentially an obligate air breather and appears to experience facultative hypometabolism during immersion. Cardisoma hirtipes has a haemocyanin with a high affinity for O(2) that facilitates loading from air but makes 30% of the Hc bound O(2) inaccessible. The gecarcinids but not P. warreni show increased diffusion limitation for O(2) over the lung during exercise. Gecarcoidea natalis outperforms C. hirtipes by virtue of a unique haemolymph shunt from the lung into the gills. Paradoxically, it is modifications of the gills for aerial O(2) uptake in G. natalis that allow for relatively greater haemolymph oxygenation. Despite showing decreased arterial-venous DeltaPo(2), P. warreni increased the arterial-venous Delta[O(2)] with no recourse to anaerobiosis during 5 min exercise. In the short term, P. warreni is more adept at walking than C. hirtipes. The breeding migrations of C. hirtipes and G. natalis were completely aerobic, but G. natalis walk farther and probably faster. Seasonal changes in underlying

  10. 76 FR 98 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 5 to the Golden Crab...

    Science.gov (United States)

    2011-01-03

    ..., and South Atlantic; Amendment 5 to the Golden Crab Fishery Management Plan of the South Atlantic... management actions to be included in Amendment 5 to the Golden Crab Fishery Management Plan of the South... for the golden crab fishery. The purpose of this NOI is to solicit public comments on the scope...

  11. Associations between dioxins/furans and dioxin-like PCBs in estuarine sediment and blue crab

    Science.gov (United States)

    Liebens, J.; Mohrherr, C.J.; Karouna-Renier, N. K.; Snyder, R.A.; Rao, K.R.

    2011-01-01

    The objective of the present study was to evaluate the relationships between the quantity, toxicity, and compositional profile of dioxin/furan compounds (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in estuarine sediment and in the blue crab (Callinectes sapidus). Sediment and blue crab samples were collected in three small urban estuaries that are in relatively close proximity to each other. Results show that differences between PCDD/F and DL-PCB mass concentrations and total toxic equivalents (TEQ) toxicity in sediments of the three estuaries are reflected in those of the blue crab. TEQs are higher in the hepatopancreas of the crabs than in the sediment, but the concentration factor is inversely proportional to the TEQ in the sediments. Congener profiles in the crabs are systematically different from those in the sediments, and the difference is more pronounced for PCDD/Fs than for DL-PCBs, possibly due to differences in metabolization rates. Compared with sediment profiles, more lesser-chlorinated PCDD/Fs that have higher TEFs accumulate in crab hepatopancreas. This selective bioaccumulation of PCDD/Fs results in a TEQ augmentation in crab hepatopancreas compared with sediments. The bioaccumulation in the blue crab is also selective for PCDD/Fs over DL-PCBs. ?? 2011 Springer Science+Business Media B.V.

  12. Differential detection of shrimp and crab for food labeling using polymerase chain reaction.

    Science.gov (United States)

    Taguchi, Hiromu; Watanabe, Satoshi; Temmei, Yusuke; Hirao, Takashi; Akiyama, Hiroshi; Sakai, Shinobu; Adachi, Reiko; Sakata, Kozue; Urisu, Atsuo; Teshima, Reiko

    2011-04-27

    Shrimp and crab are well-known as allergenic ingredients. According to Japanese food allergy labeling regulations, shrimp species (including prawns, crayfishes, and lobsters) and crab species must be differentially declared when ≥10 ppm (total protein) of an allergenic ingredient is present. However, the commercial ELISA tests for the detection of crustacean proteins cannot differentiate between shrimp and crab. Therefore, two methods were developed to discriminate shrimp and crab: a shrimp-PCR method with postamplification digestion and a crab-PCR method that specifically amplifies a fragment of the 16S rRNA gene. The sensitivity and specificity of both PCR methods were verified by experiments using DNA extracted from 15 shrimp species, 13 crab species, krill, mysid, mantis shrimp, other food samples (cephalopod, shellfish, and fish), incurred foods, and commercial food products. Both PCR methods could detect 5 pg of DNA extracted from target species and 50 ng of genomic DNA extracted from incurred foods containing 10 ppm (μg/g) total protein of shrimp or crab. The two PCR methods were considered to be specific enough to separately detect species belonging to shrimp and crab. Although false-positive and false-negative results were obtained from some nontarget crustacean species, the proposed PCR methods, when used in conjunction with ELISA tests, would be a useful tool for confirmation of the validity of food allergy labeling and management of processed food safety for allergic patients.

  13. Purification and characterization of a cadmium-induced metallothionein from the shore crab Carcinus maenas (L.)

    DEFF Research Database (Denmark)

    Pedersen, K L; Pedersen, S N; Højrup, P

    1994-01-01

    Two metallothionein variants were purified from the midgut gland of crabs (Carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). One of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). The purification method involved acetone precipitation, ...

  14. The mud crab Scylla serrata is one of the largest por- tunids and is ...

    African Journals Online (AJOL)

    denise

    crabs are readily available to coastal fishers (Macnae. 1968, Hirata 1991 ... holes above the upper mid-littoral zone (Nandi and. Dev-Roy ... However, as people move to the coastal ... The present study investigates the crab population structure ...

  15. The first finding of the crab Ctenocheles (Decapoda in Oligocene beds in Slovenia

    Directory of Open Access Journals (Sweden)

    Vasja Mikuž

    2003-06-01

    Full Text Available In the paper remains of crabs of genus Ctenocheles are discussed. They were found in the Oligocene grey marly mudstone at Čeplje at Vransko. This is the first evidence of this crab genus in Slovenia. In the Oligocene mudstone at ^eplje also numerous other fossilremains were registred, and also abundant septarian concretions.

  16. Dioxins, PCBs and heavy metals in Chinese mitten crabs from Dutch rivers and lakes.

    Science.gov (United States)

    Hoogenboom, Ron L A P; Kotterman, Michiel J J; Hoek-van Nieuwenhuizen, Marion; van der Lee, Martijn K; Mennes, Wim C; Jeurissen, Suzanne M F; van Leeuwen, Stefan P J

    2015-03-01

    Chinese mitten crab is an invasive species in many European rivers and lakes. Data from the UK indicated high levels of dioxins and PCBs, in particular in the brown meat in the body. This was confirmed by studies in the Netherlands, showing average levels of dioxins and PCBs in the meat in the body of 43 pg TEQ g(-1) ww in crabs caught in the large rivers. Levels in crab of lakes in the Northern part of the Netherlands were on average 3.7-fold lower. Consumption of crabs from polluted areas results in a relatively high dose of dioxins and dl-PCBs and could significantly increase the intake above the TWI. However, in general consumption of these crabs is low, even in the Asian sub-population in the Netherlands. Cadmium and lead levels were higher in crabs from contaminated areas, but for mercury and arsenic there was no clear difference. Consumption of crabs would not result in significant risks for cadmium and mercury. For lead the daily intake could be raised above the BMDL01 for neurodevelopmental toxicity, but this would only occur on a limited number of days. For arsenic the exposure would exceed the lower end of the BMDL01 values for certain cancers, but again, the infrequent consumption by most consumers reduces this risk. Furthermore, speciation showed that most arsenic in crabs was probably not a toxic inorganic form, but likely to be in an organic form.

  17. Microsatellite analysis of genetic diversity and population structure of Chinese mitten crab (Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    Yumei Chang; Liqun Liang; Haitao Ma; Jianguo He; Xiaowen Sun

    2008-01-01

    Chinese mitten crab (Eriocheir sinensis) has higher commercial value as food source than any other species of Eriocheir in China.To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems,two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank.Basic statistics showed that the average observed heterozygosity (Ho) amongst populations ranged from 0.5789 to 0.6824.However,a remarkable presence of inbreeding and heterozygote deficiencies were observed.To analyze population structure,pairwise FST coefficients explained only ~10.3% variability from the subdivision of mitten crab populations,the remaining variability stems from the subdivision within subpopulations.Although the four populations had slight differentiation,different allelic frequencies resulted in distinct population structures.Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab,with an approximate membership of 95%.Whereas,another fanning population was clustered singly to the phylogenetic branch of the Liaohe crab,with a membership of 97.1%.The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems.Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.

  18. Epidemiology of acanthocephalan infections in crabs from the Bahía Blanca Estuary, Argentina.

    Science.gov (United States)

    La Sala, L F; Perez, A M; Martorelli, S R

    2012-12-01

    This study was conducted in two populations of crabs, Cyrtograpsus angulatus and Neohelice granulata from the Bahía Blanca Estuary, in Argentina, to identify risk factors for infection by the acanthocephalan Profilicollis chasmagnathi and to assess the association between infection and mortality of these hosts. Cyrtograpsus angulatus and N. granulata crabs were sampled seasonally over the course of a year, and spring sampling included collection of dead crabs predated by Olrog's gulls in a nearby breeding colony. Potential risk factors for infection were assessed and the number of cystacanth larvae per crab was counted. In C. angulatus, the odds of infection increased by 7% for each millimetre increase in carapace length, and were nearly 17 times greater in crabs sampled from the Olrog's gull feeding area compared with those sampled from nests in the breeding colony. For every millimetre increase in carapace length in N. granulata, the odds of infection increased by 13% in crabs from the breeding colony, and by 32% in crabs from the feeding area. Mean intensity of infection in N. granulata increased by 16.5% for each additional millimetre of carapace width. The level of parasite aggregation was lowest in the largest C. angulatus and highest in N. granulata predated by Olrog's gull. The results show that host size is the most important factor influencing infection prevalence in both crab species and intensity of infection in N. granulata, and suggest the presence of parasite-induced mortality in the populations studied.

  19. Prevalence and distribution of three protozoan symbionts in blue crab (Callinectes sapidus) populations across Louisiana, USA.

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Anderson Lively, Julie A

    2015-05-11

    Louisiana has one of the largest blue crab (Callinectes sapidus) fisheries in the USA, but little is known about blue crab diseases, parasites, and symbionts in this area. In 2013-2014, large juvenile and adult blue crabs were collected at 4 diverse sites to determine the prevalence of the protozoan symbionts associated with black gill disease (Lagenophrys callinectes), buckshot crabs (Urosporidium crescens), and bitter crab disease (Hematodinium perezi). A high aggregate prevalence of L. callinectes (93.2%) was identified across all seasons at all 4 collection sites regardless of salinity. A moderately low aggregate prevalence of U. crescens (22.4%) was identified across all seasons and sites. Prevalence of U. crescens depended on site salinity, with only 10% of infections detected at sites with callinectes and U. crescens are commensal parasites of blue crabs, infections can result in unmarketable and unappealing meat. In the Louisiana fishery, H. perezi has been blamed circumstantially for adult mortalities in the low salinity nearshore fishing grounds. Despite this, H. perezi was not detected in any of the large crabs sampled, even from the low salinity sites. The prevalence data reported here for these 3 protozoans are the first to include blue crabs sampled seasonally at multiple locations along the Louisiana coast over the period of a year.

  20. Evolution of crabs – history and deconstruction of a prime example of convergence

    NARCIS (Netherlands)

    Scholtz, G.

    2014-01-01

    Compared with the elongate bodies of shrimps or lobsters, crabs are characterised by a compact body organisation with a depressed, short carapace and a ventrally folded pleon. The evolutionary transformation from a lobster-like crustacean towards a crab is called ‘carcinization’ and has been

  1. Summary of the 3rd LHC Crab Cavity Workshop (LHC-CC09)

    CERN Document Server

    Zimmermann, Frank; Koutchouk, Jean-Pierre; Delayen, Jean; Pierini, Paolo; Ciapala, Edmond; McIntosh, Peter; Giovannozzi, Massimo; Brüning, Oliver; Collier, Paul; Funakoshi, Yoshihiro

    2010-01-01

    The 3rd workshop on crab compensation for the LHC luminosity upgrade (LHC-CC09) was held September 16-18, 2008 at CERN, Geneva, Switzerland. The workshop was organized by joint collaboration of CERN, EUCARD, KEK and US-LARP. Approximately 50 workshop participants from 3 continents and several institutions discussed the future strategy of implementing crab cavities in the LHC

  2. Dungeness crab survey for the Southwest Ocean Disposal Site off Grays Harbor, Washington, June 1990

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, B.J.; Pearson, W.H. (Battelle/Marine Sciences Lab., Sequim, WA (United States))

    1991-09-01

    As part of the Grays Harbor Navigation Improvement Project, the Seattle District of the US Army Corps of Engineers has begun active use of the Southwest Ocean Disposal Site off Grays Harbor, Washington. This survey was to verify that the location of the area of high crab density observed during site selection surveys has not shifted into the Southeast Ocean Disposal Site. In June 1990, mean densities of juvenile Dungeness crab were 146 crab/ha within the disposal site and 609 crab/ha outside ad north of the disposal site. At nearshore locations outside the disposal site, juvenile crab density was 3275 crab/ha. Despite the low overall abundance, the spatial distribution of crab was such that the high crab densities in 1990 have remained outside the Southwest Ocean Disposal Site. The survey data have confirmed the appropriateness of the initial selection of the disposal site boundaries and indicated no need to move to the second monitoring tier. 8 refs., 9 figs., 2 tabs.

  3. 50 CFR 654.24 - Shrimp/stone crab separation zones.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shrimp/stone crab separation zones. 654.24... Measures § 654.24 Shrimp/stone crab separation zones. Five zones are established in the management area and Florida's waters off Citrus and Hernando Counties for the separation of shrimp trawling and stone...

  4. Metabolism of pectenotoxins in brown crabs Cancer pagurus fed with blue mussels Mytilus edulis

    Institute of Scientific and Technical Information of China (English)

    LI Zhaoxin

    2009-01-01

    We investigated the metabolism of pectenotoxins in brown crabs (Cancer pagurus). The crabs were fed with blue mussels (Mytilus edulis) for 21 d then depurated for 42 d. We extracted the toxins from the digestive glands of contaminated crabs, uncontaminated crabs (control group), and the meat of blue mussels using methanol. Extracts of the crab digestive glands were fractionated by liquid-liquid partitioning and solid phase extraction. The fractions were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and liquid chromatography coupled with ion-trap mass spectrometry (LC-MSn). We detected a new PTX-like compound, designated as metabolite-1. The MS2 mass spectrum of the metabolite-1 [M+Na]+ ion at m/z 897.5 revealed fragment ions at m/z 853.5 and 555.5, typical of those exhibited by other pectenotoxins.

  5. Effects of tributyltin exposure in hermit crabs: Clibanarius vittatus as a model.

    Science.gov (United States)

    Sant'Anna, Bruno Sampaio; Santos, Dayana Moscardi Dos; Marchi, Mary Rosa Rodrigues de; Zara, Fernando José; Turra, Alexander

    2012-03-01

    Tributyltin (TBT) contamination affects the reproductive system of many species of invertebrates worldwide. The present study was designed to evaluate the effects of exposure to TBT pollution on the reproduction of the hermit crab Clibanarius vittatus. An orthogonal experiment was designed with two treatments: contamination (with or without TBT in the food) and crab sex (males and females). The animals were reared in the laboratory for nine months, and macroscopic and histological analyses of reproductive organs were carried out after the end of the experiment. Tributyltin was recorded in exposed crabs, but no morphological alterations were detected in the gonads of males, regardless of whether they were exposed to TBT. In contrast, females exposed to TBT displayed disorganization and atrophy of their ovaries, thus directly affecting reproduction in this hermit crab species. This effect observed in female hermit crabs may harm populations located in harbor regions, where TBT concentration is high, even after the worldwide TBT ban.

  6. Pharmacokinetics of cefovecin (Convenia) in white bamboo sharks (Chiloscyllium plagiosum) and Atlantic horseshoe crabs (Limulus polyphemus).

    Science.gov (United States)

    Steeil, James C; Schumacher, Juergen; George, Robert H; Bulman, Frank; Baine, Katherine; Cox, Sherry

    2014-06-01

    Cefovecin was administered to six healthy adult white bamboo sharks (Chiloscyllium plagiosum) and six healthy adult Atlantic horseshoe crabs (Limulus polyphemus) to determine its pharmacokinetics in these species. A single dose of cefovecin at 8 mg/kg was administered subcutaneously in the epaxial region of the bamboo sharks and in the proximal articulation of the lateral leg of the horseshoe crabs. Blood and hemolymph samples were collected at various time points from bamboo sharks and Atlantic horseshoe crabs. High performance liquid chromatography was performed to determine plasma levels of cefovecin. The terminal halflife of cefovecin in Atlantic horseshoe crabs was 37.70 +/- 9.04 hr and in white bamboo sharks was 2.02 +/- 4.62 hr. Cefovecin concentrations were detected for 4 days in white bamboo sharks and for 14 days in Atlantic horseshoe crabs. No adverse effects associated with cefovecin administration were seen in either species.

  7. Chitin-Chitosan Yield of Freshwater Crab (Potamon potamios, Olivier 1804 Shell

    Directory of Open Access Journals (Sweden)

    Yildiz Bolat*, Şengül Bilgin, Ali Günlü, Levent Izci, Seval Bahadır Koca, Soner Çetinkaya1 and Habil Uğur Koca

    2010-10-01

    Full Text Available In this study, freshwater crab (Potamon potamios, Olivier 1804, economically unevaluated, was used to obtain chitin-chitosan. Chitin-chitosan was extracted with standardized modified chemical method. Chitosan was extracted with demineralization, deproteinization, decoloration (chitin and deacetylation (chitosan. Grinded shell was obtained as 60% after boiling, drying and grinding processes. Chitosan yield of crab shell was determined as 4.65% from grinded crab shell after demineralization (yield is 34.32%, deproteinization (yield is 7.25%, decoloration (yield is 6.83% and deacetylation processes. Moreover, freshwater crab stock was estimated with catch per unit effort (CPUE data in Eğirdir Lake for calculation of quantity of chitosan. Population size was estimated between 12.85±11.88 and 23.86±25.39 tones and freshwater crab was determined as an appropriate crustacean to obtain chitin-chitosan.

  8. Did the Crab Pulsar Undergo a Small Glitch in 2006 late March/early April?

    CERN Document Server

    Vivekanand, M

    2016-01-01

    On 2006 August 23 the Crab Pulsar underwent a glitch, that was reported by the Jodrell Bank and the Xinjiang radio observatories. Neither data are available to the public. However, the Jodrell group publishes monthly arrival times of the Crab Pulsar pulse (their actual observations are done daily), using which it is shown that about five months earlier, the Crab Pulsar most probably underwent a small glitch, which has not been reported before. Neither observatory discusses the detailed analysis of data from 2006 March to August; either they may not have detected this small glitch, or may have attributed it to timing noise in the Crab Pulsar. The above result is verified using X-ray data from the RXTE observatory. If this is indeed true, this may probably be the smallest glitch observed in the Crab Pulsar so far, whose implications are discussed. This work addresses the confusion possible between small magnitude glitches and timing noise in pulsars.

  9. AFSC/RACE/SAP/Long: Data from: Habitat, predation, growth, and coexistence: Could interactions between juvenile red and blue king crabs limit blue king crab productivity?

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is from a series of laboratory experiments examining the interactions between red and blue king crabs and habitat. We examined how density and predator...

  10. Comparative proteomics of uropathogenic Escherichia coli during growth in human urine identify UCA-like (UCL) fimbriae as an adherence factor involved in biofilm formation and binding to uroepithelial cells.

    Science.gov (United States)

    Wurpel, Daniël J; Totsika, Makrina; Allsopp, Luke P; Webb, Richard I; Moriel, Danilo G; Schembri, Mark A

    2016-01-10

    Uropathogenic Escherichia coli (UPEC) are the primary cause of urinary tract infection (UTI) in humans. For the successful colonisation of the human urinary tract, UPEC employ a diverse collection of secreted or surface-exposed virulence factors including toxins, iron acquisition systems and adhesins. In this study, a comparative proteomic approach was utilised to define the UPEC pan and core surface proteome following growth in pooled human urine. Identified proteins were investigated for subcellular origin, prevalence and homology to characterised virulence factors. Fourteen core surface proteins were identified, as well as eleven iron uptake receptor proteins and four distinct fimbrial types, including type 1, P, F1C/S and a previously uncharacterised fimbrial type, designated UCA-like (UCL) fimbriae in this study. These pathogenicity island (PAI)-associated fimbriae are related to UCA fimbriae of Proteus mirabilis, associated with UPEC and exclusively found in members of the E. coli B2 and D phylogroup. We further demonstrated that UCL fimbriae promote significant biofilm formation on abiotic surfaces and mediate specific attachment to exfoliated human uroepithelial cells. Combined, this study has defined the surface proteomic profiles and core surface proteome of UPEC during growth in human urine and identified a new type of fimbriae that may contribute to UTI.

  11. Effects of ocean acidification on juvenile red king crab (Paralithodes camtschaticus) and Tanner crab (Chionoecetes bairdi) growth, condition, calcification, and survival.

    Science.gov (United States)

    Long, William Christopher; Swiney, Katherine M; Harris, Caitlin; Page, Heather N; Foy, Robert J

    2013-01-01

    Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0), pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4-11.9 °C). In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades.

  12. Effects of ocean acidification on juvenile red king crab (Paralithodes camtschaticus and Tanner crab (Chionoecetes bairdi growth, condition, calcification, and survival.

    Directory of Open Access Journals (Sweden)

    William Christopher Long

    Full Text Available Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0, pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4-11.9 °C. In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades.

  13. Carbon and nitrogen balance of leaf-eating sesarmid crabs ( Neoepisesarma versicolor) offered different food sources

    Science.gov (United States)

    Thongtham, Nalinee; Kristensen, Erik

    2005-10-01

    Carbon and nitrogen budgets for the leaf-eating crab, Neoepisesarma versicolor, were established for individuals living on pure leaf diets. Crabs were fed fresh (green), senescent (yellow) and partly degraded (brown) leaves of the mangrove tree Rhizophora apiculata. Ingestion, egestion and metabolic loss of carbon and nitrogen were determined from laboratory experiments. In addition, bacterial abundance in various compartments of the crabs' digestive tract was enumerated after dissection of live individuals. Ingestion and egestion rates (in terms of dry weight) were highest, while the assimilation efficiency was poorest for crabs fed on brown leaves. The low assimilation efficiency was more than counteracted by the high ingestion rate providing more carbon for growth than for crabs fed green and yellow leaves. In any case, the results show that all types of leaves can provide adequate carbon while nitrogen was insufficient to support both maintenance (yellow leaves) and growth (green, yellow and brown leaves). Leaf-eating crabs must therefore obtain supplementary nitrogen by other means in order to meet their nitrogen requirement. Three hypotheses were evaluated: (1) crabs supplement their diet with bacteria and benthic microalgae by ingesting own faeces and/or selective grazing at the sediment surface; (2) assimilation of symbiotic nitrogen-fixing bacteria in the crabs' own intestinal system; and (3) nitrogen storage following occasional feeding on animal tissues (e.g. meiofauna and carcasses). It appears that hypothesis 1 is of limited importance for N. versicolor since faeces and sediment can only supply a minor fraction of the missing nitrogen due to physical constraints on the amount of material the crabs can consume. Hypothesis 2 can be ruled out because tests showed no nitrogen fixation activity in the intestinal system of N. versicolor. It is therefore likely that leaf-eating crabs provide most of their nitrogen requirement from intracellular deposits

  14. Effects of temperature on cellular and biochemical parameters in the crab Carcinus aestuarii (Crustacea, Decapoda).

    Science.gov (United States)

    Matozzo, Valerio; Gallo, Chiara; Marin, Maria Gabriella

    2011-06-01

    The effects of temperature on cellular and biochemical parameters of the crab Carcinus aestuarii were evaluated. Crabs were kept for 7 days at 4, 17 (reference value) and 30 °C (salinity of 35 psu), and total haemocyte count (THC), haemocyte volume, haemocyte proliferation, phenoloxidase (PO) activity in both haemocyte lysate (HL) and cell-free haemolymph (CFH), CFH total protein and glucose levels, superoxide dismutase (SOD) and catalase (CAT) activities in both gills and digestive gland were evaluated. The lowest and the highest temperature significantly decreased THC, whereas haemocyte volume and haemolymph glucose concentration did not differ significantly among experimental conditions. Haemolymph protein concentration significantly reduced in crabs maintained at 30 °C, when compared with that of animals kept at 4 and 17 °C. Haemocyte proliferation increased significantly in crabs kept at 4 and 30 °C, when compared with that of crabs held at 17 °C. Likewise, a significantly higher PO activity was recorded in CFH from crabs kept at 4 and 30 °C, than in control crabs. Conversely, PO activity did not vary significantly in HL. With regard to antioxidant enzyme activities, a significant decrease in CAT activity was observed in gills from crabs kept at 4 °C, when compared to that of crabs kept at 17 °C and 30 °C. Results obtained demonstrated that the highest and lowest temperature tested influenced crab biological responses, and indicated that C. aestuarii modulated its cellular and biochemical parameters (mainly haemocyte proliferation, CFH protein concentrations and CFH PO activity) in order to cope with temperature. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. A low intensity sampling method for assessing blue crab abundance at Aransas National Wildlife Refuge and preliminary results on the relationship of blue crab abundance to whooping crane winter mortality

    Science.gov (United States)

    Pugesek, Bruce H.; Baldwin, Michael J.; Stehn, Thomas; Folk, Martin J.; Nesbitt, Stephen A.

    2008-01-01

    We sampled blue crabs (Callinectes sapidus) in marshes on the Aransas National Wildlife Refuge, Texas from 1997 to 2005 to determine whether whooping crane (Grus americana) mortality was related to the availability of this food source. For four years, 1997 - 2001, we sampled monthly from the fall through the spring. From these data, we developed a reduced sampling effort method that adequately characterized crab abundance and reduced the potential for disturbance to the cranes. Four additional years of data were collected with the reduced sampling effort methods. Yearly variation in crab numbers was high, ranging from a low of 0.1 crabs to a high of 3.4 crabs per 100-m transect section. Mortality among adult cranes was inversely related to crab abundance. We found no relationship between crab abundance and mortality among juvenile cranes, possibly as a result of a smaller population size of juveniles compared to adults.

  16. Discovery of Optical Circular Polarization of the Crab Pulsar

    Science.gov (United States)

    Wiktorowicz, Sloane; Ramirez-Ruiz, Enrico; Illing, Rainer M. E.; Nofi, Larissa

    2015-01-01

    Nearly 50 years ago at the Lick 3-m Shane telescope, Wampler et al. (1969) discovered optical linear depolarization of the Crab pulsar's main pulse and interpulse regions, which led to the interpretation of synchrotron radiation as the source of pulsed emission. We present phase-resolved, simultaneous linear and circular polarization of the Crab pulsar using the POLISH2 aperture-integrated, optical polarimeter at the Lick 3-m telescope. The two photoelastic modulators in this instrument, used instead of waveplates, AC couple incident Stokes Q, U, and V to unique, independent frequencies between 10 and 200 kHz. Stokes I is measured from the time-averaged intensity of the beam. Thus, this instrument is capable of simultaneous measurement of Q/I, U/I, and V/I in 20 microsecond temporal bins with part-per-million nightly sensitivity on naked eye stars. From just one hour of observations, we confirm linear depolarization of the main pulse and interpulse regions, and we also discover significant optical circular polarization at all pulsar phases. Furthermore, we observe circular depolarization of the main pulse and interpulse regions with respect to the off-pulse region. Observations of strongly polarized calibration stars, as well as lamp observations with a linear polarizer inserted upstream of the modulators, demonstrate that circular polarization results obtained on the Crab pulsar are not due to spurious, instrumental conversion of linear to circular polarization. Therefore, using novel instrumentation, our observations shed new light on this enigmatic object, and we demonstrate that the Lick 3-m Shane telescope still remains at the cutting edge for optical polarimetry.

  17. Peering into the Heart of the Crab Nebula

    Science.gov (United States)

    2000-01-01

    In the year 1054 A.D., Chinese astronomers were startled by the appearance of a new star, so bright that it was visible in broad daylight for several weeks. Today, the Crab Nebula is visible at the site of the 'Guest Star.' Located about 6,500 light-years from Earth, the Crab Nebula is the remnant of a star that began its life with about 10 times the mass of our own Sun. Its life ended on July 4, 1054 when it exploded as a supernova. In this image, NASA's Hubble Space Telescope has zoomed in on the center of the Crab to reveal its structure with unprecedented detail. The Crab Nebula data were obtained by Hubble's Wide Field and Planetary Camera 2 in 1995. Images taken with five different color filters have been combined to construct this new false-color picture. Resembling an abstract painting by Jackson Pollack, the image shows ragged shards of gas that are expanding away from the explosion site at over 3 million miles per hour. The core of the star has survived the explosion as a pulsar, visible in the Hubble image as the lower of the two moderately bright stars to the upper left of center. The pulsar is a neutron star that spins on its axis 30 times a second. It heats its surroundings, creating the ghostly diffuse bluish-green glowing gas cloud in its vicinity, including a blue arc just to its right. The colorful network of filaments is the material from the outer layers of the star that was expelled during the explosion. The picture is somewhat deceptive in that the filaments appear to be close to the pulsar. In reality, the yellowish green filaments toward the bottom of the image are closer to us, and approaching at some 300 miles per second. The orange and pink filaments toward the top of the picture include material behind the pulsar, rushing away from us at similar speeds. The various colors in the picture arise from different chemical elements in the expanding gas, including hydrogen (orange), nitrogen (red), sulfur (pink), and oxygen (green). The shades

  18. On Calibrations Using the Crab Nebula as a Standard Candle

    Science.gov (United States)

    Weisskopf, Martin; Guainazzi, Matteo; Jahoda, Keith; Shaposhnikov, Nikolai; ODell, Stephen; Zavlin, Vyacheslav; Wilson-Hodge, Colleen; Elsner, Ronald

    2009-01-01

    Inspired by a recent paper (Kirsch et al. 2005) on possible use of the Crab Nebula as a standard candle for calibrating X-ray response func tions, we examine possible consequences of intrinsic departures from a single (absorbed) power law upon such calibrations. We limited our analyses to three more modern X-ray instruments -- the ROSAT/PSPC, th e RXTE/PCA, and the XMM-Newton/EPIC-pn. The results are unexpected an d indicate a need to refine two of the three response functions studi ed. The implications for Chandra will be discussed.

  19. OBSERVATION AND SPECTRAL MEASUREMENTS OF THE CRAB NEBULA WITH MILAGRO

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, A. A. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Allen, B. T.; Chen, C. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Atkins, R. [Department of Physics, University of Wisconsin, 1150 University Ave, Madison, WI 53706 (United States); Aune, T.; Benbow, W.; Coyne, D. G.; Dorfan, D. E. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States); Berley, D.; Blaufuss, E.; Bussons, J. [Department of Physics, University of Maryland, College Park, MD 20742 (United States); Bonamente, E.; Galbraith-Frew, J. [Department of Physics, Michigan Technological University, Houghton, MI 49931 (United States); Christopher, G. E.; Fleysher, L.; Fleysher, R. [Department of Physics, New York University, New York, NY 10003 (United States); DeYoung, T.; Falcone, A. [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Dingus, B. L. [Group P-23, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ellsworth, R. W. [School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States); and others

    2012-05-01

    The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV-100 TeV gamma-ray air showers by observing the particle footprint reaching the ground. The fraction of detectors recording signals from photons at the ground is a suitable proxy for the energy of the primary particle and has been used to measure the photon energy spectrum of the Crab Nebula between {approx}1 and {approx}100 TeV. The TeV emission is believed to be caused by inverse-Compton upscattering of ambient photons by an energetic electron population. The location of a TeV steepening or cutoff in the energy spectrum reveals important details about the underlying electron population. We describe the experiment and the technique for distinguishing gamma-ray events from the much more-abundant hadronic events. We describe the calculation of the significance of the excess from the Crab and how the energy spectrum is fitted. The differential photon energy spectrum, including the statistical errors from the fit, obtained using a simple power-law hypothesis for data between 2005 September and 2008 March is (6.5 {+-} 0.4) Multiplication-Sign 10{sup -14}(E/10 TeV){sup -3.1{+-}0.1}(cm{sup 2} s TeV ){sup -1} between {approx}1 TeV and {approx}100 TeV. Allowing for a possible exponential cutoff, the photon energy spectrum is fitted as (2.5{sup +0.7}{sub -0.4}) Multiplication-Sign 10{sup -12}(E/3 TeV){sup -2.5{+-}0.4}exp (- E/32{sup +39}{sub -18} TeV) (cm{sup 2} s TeV){sup -1}. The results are subject to an {approx}30% systematic uncertainty in the overall flux and an {approx}0.1 systematic uncertainty in the power-law indices quoted. Uncertainty in the overall energy scale has been absorbed into these errors. Fixing the spectral index to values that have been measured below 1 TeV by IACT experiments (2.4-2.6), the fit to the Milagro data suggests that Crab exhibits a

  20. Machine Protection Studies for a Crab Cavity in the LHC

    CERN Document Server

    Yee-Rendon, B; Baer, T; Barranco, J; Calaga, R; Marsili, A; Tomas, R; Zimmermann, F

    2013-01-01

    Crab cavities (CCs) apply a transverse kick that rotates the bunches so as to have a head-on collision at the interaction point (IP). Such cavities were successfully used to improve the luminosity of KEKB. They are also a key ingredient of the HL-LHC project to increase the luminosity of the LHC. As CCs can rapidly change the particle trajectories, machine protection studies are required to assess the beam losses due to fast CC failures. In this paper, we discuss the effect of rapid voltage or phase changes in a CC for the HL-LHC layout using measured beam distributions from the present LHC.

  1. High Luminosity LHC matching section layout vs crab cavity voltage

    CERN Document Server

    Dalena, B; Chance, A; De Maria, R; Fartoukh, S

    2013-01-01

    In the framework of the HiLumi-LHC project we present a new possible variant for the layout of the LHC matching section located in the high luminosity insertions. This layout is optimized to reduce the demand on the voltage of the crab cavities, while substantially improving the optics squeeze-ability, both in ATS [1] and non-ATS mode. This new layout will be described in details together with its performance figures in terms of mechanical acceptance, chromatic properties and optics flexibility.

  2. POSSIBILITIES OF CULTURING BIG SEA CRABS (LOBSTERS, SPINY LOBSTERS)

    OpenAIRE

    Ivančica Strunjak-Perović; Emin Teskeredžić; Marija Tomec

    1999-01-01

    By the end of the 19 th century an experimental work on culturing big sea crabs began in Europe and North America. Great demand for their flesh as well as their high price urged many institutions to explore the possibilities of a commercial production in varios parts of the world. Lobsters (Homarus sp.) were mainly used for experimenting, so that the most data available refer to them. Because of the complicated larva stage spiny lobster culturing is mainly being carried out in experimental ci...

  3. Impacts to Dungeness Crab from the Southwest Washington Littoral Drift Restoration Project

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Greg D.; Kohn, Nancy P.; Pearson, Walter H.; Skalski, J R.

    2005-11-09

    The Benson Beach littoral drift restoration project is a demonstration project that will replenish sand on Benson Beach, the public beach north of the North Jetty at the mouth of the Columbia River (MCR), using material dredged from the river during normal maintenance dredging of the navigational channel. A U.S. Army Corps of Engineers (Corps) proposal involves pumping the material from a sump area on the south side of the jetty to Benson Beach using a cutter suction dredge, also known as a pipeline dredge. If this one-time demonstration project proves feasible and successful, up to a million cubic yards of sediment could be used to replenish the outer coast littoral drift system in successive years by the same process. The primary goal of this study was to assess the potential risk of impacts to Dungeness crab from the proposed Benson Beach littoral drift restoration process of using the cutter suction dredge to move sediment from the proposed sump area on one side of the North Jetty to the beach on the other side of the jetty. Because there are no direct measurements of crab entrainment by pipeline dredge operating outside of the lower Columbia River navigation channel, dredge impacts for the proposed demonstration project were estimated using a modification of the dredge impact model (DIM) of Armstrong et al. (1987). The model estimates adult equivalent loss (AEL) of crabs using crab population density from trawl surveys, dredge project information (gear type, season, location, volume), and an entrainment function relating crab population density to entrainment by the dredge. The input used in applying the DIM to the Benson Beach littoral drift restoration included the specific dredging scenario provided by the Corps, existing data on crab density in previously proposed sump areas, and a series of entrainment functions. A total of fourteen scenarios were modeled and the outcomes compared with six reference scenarios intended to represent realistic to worst cases

  4. Impacts to Dungeness Crab from the Southwest Washington Littoral Drift Restoration Project

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Greg D.; Kohn, Nancy P.; Pearson, Walter H.; Skalski, J R.

    2005-11-09

    The Benson Beach littoral drift restoration project is a demonstration project that will replenish sand on Benson Beach, the public beach north of the North Jetty at the mouth of the Columbia River (MCR), using material dredged from the river during normal maintenance dredging of the navigational channel. A U.S. Army Corps of Engineers (Corps) proposal involves pumping the material from a sump area on the south side of the jetty to Benson Beach using a cutter suction dredge, also known as a pipeline dredge. If this one-time demonstration project proves feasible and successful, up to a million cubic yards of sediment could be used to replenish the outer coast littoral drift system in successive years by the same process. The primary goal of this study was to assess the potential risk of impacts to Dungeness crab from the proposed Benson Beach littoral drift restoration process of using the cutter suction dredge to move sediment from the proposed sump area on one side of the North Jetty to the beach on the other side of the jetty. Because there are no direct measurements of crab entrainment by pipeline dredge operating outside of the lower Columbia River navigation channel, dredge impacts for the proposed demonstration project were estimated using a modification of the dredge impact model (DIM) of Armstrong et al. (1987). The model estimates adult equivalent loss (AEL) of crabs using crab population density from trawl surveys, dredge project information (gear type, season, location, volume), and an entrainment function relating crab population density to entrainment by the dredge. The input used in applying the DIM to the Benson Beach littoral drift restoration included the specific dredging scenario provided by the Corps, existing data on crab density in previously proposed sump areas, and a series of entrainment functions. A total of fourteen scenarios were modeled and the outcomes compared with six reference scenarios intended to represent realistic to worst cases

  5. Comparison of Gender Differences in Nutritional Value and Key Odor Profile of Hepatopancreas of Chinese Mitten Crab (Eriocheir Sinensis).

    Science.gov (United States)

    Wu, Na; Wang, Xi-Chang

    2017-02-01

    The nutritional value and key odor profile of hepatopancreas of Chinese mitten crab (Eriocheir sinensis) was evaluated, and gender differences in terms of edible yield, proximate composition, different lipid fractions, fatty acid composition, and key odor compounds were compared. Total lipids were separated into different lipid fractions using silicic acid columns. And odorants were detected by monolithic material sorptive extraction coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Furthermore, detected frequency and odor intensity method of GC-O were applied to select key odor compounds in steamed E. sinensis. The results showed male crabs (34.06%) had a higher edible yield than female crabs (32.42%). Hepatopancreas was the most abundant portion in both genders, which contained high lipid content. Higher contents of triacylglycerols, sterols, free fatty acids, and phosphatidylethanolamine in female crabs resulted in a significant higher total lipid content in females (40.05%) than in males (37.94%). Meanwhile, total monounsaturated fatty acids and polyunsaturated fatty acids of female crabs had significant higher content than male crabs, and the ratio of docosahexaenoic acid to eicosapentaenoic acid of female crabs (1.26) showed higher value than male crabs (1.18), which indicated that female crabs had higher nutritional value than male crabs. For further analyses, unique odor compounds detected in female crabs showed a plant/vegetable-like odor, while sweety, corn-like odor in male crabs. These suggested that hepatopancreases of female crabs are healthier than male crabs for human consumption, however, they may be favored by different consumers individually due to their unique aroma profiles.

  6. Intraguild predation by shore crabs affects mortality, behavior, growth, and densities of California horn snails

    Science.gov (United States)

    Lorda, J.; Hechinger, R.F.; Cooper, S. D.; Kuris, A. M.; Lafferty, Kevin D.

    2016-01-01

    The California horn snail, Cerithideopsis californica, and the shore crabs, Pachygrapsus crassipesand Hemigrapsus oregonensis, compete for epibenthic microalgae, but the crabs also eat snails. Such intraguild predation is common in nature, despite models predicting instability. Using a series of manipulations and field surveys, we examined intraguild predation from several angles, including the effects of stage-dependent predation along with direct consumptive and nonconsumptive predator effects on intraguild prey. In the laboratory, we found that crabs fed on macroalgae, snail eggs, and snails, and the size of consumed snails increased with predator crab size. In field experiments, snails grew less in the presence of crabs partially because snails behaved differently and were buried in the sediment (nonconsumptive effects). Consistent with these results, crab and snail abundances were negatively correlated in three field surveys conducted at three different spatial scales in estuaries of California, Baja California, and Baja California Sur: (1) among 61 sites spanning multiple habitat types in three estuaries, (2) among the habitats of 13 estuaries, and (3) among 34 tidal creek sites in one estuary. These results indicate that shore crabs are intraguild predators on California horn snails that affect snail populations via predation and by influencing snail behavior and performance.

  7. The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab.

    Science.gov (United States)

    Douglass, T S; Connor, W E; Lin, D S

    1981-08-01

    In order to study the biosynthesis, composition, and origin of sterols in the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male crabs either a cholesterol-free or a high cholesterol diet for 2 to 7 weeks. The origin of sterols in these crabs, whether from biosynthesis or from the diet, was determined by tahree procedures: the incorporation of isotopic mevalonate into the cholesterol when the diet was cholesterol-free; the absorption of isotopic cholesterol and sitosterol from the diet; the cholesterol and plant sterol concentrations of hepatopancreas, plasma, and muscle under conditions of cholesterol-free and high cholesterol diets. In addition, the interconversion of cholesterol and sitosterol was investigated. Dietary sterols of plant and animal sources were readily absorbed and provided the major source of sterols for this species of crab. The biosynthesis of cholesterol from mevalonate in this crab was minimal. However, cholesterol was synthesized from dietary sitosterol by dealkylation. Cholesterol and the three plant sterols (24 epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed from 9 to 37% of the total sterols in the hepatopancreas, plasma, and muscle of the crabs fed a cholesterol-free diet.

  8. The 1997 Event in the Crab Pulsar in X-rays

    CERN Document Server

    Vivekanand, M

    2016-01-01

    In October 1997, radio pulses from the Crab Pulsar underwent abnormal delay. This was reported by two radio observatories, both of which explained this frequency dependent and time varying delay as being due to refractive effects of ionized shells in the Crab Nebula. Both groups also noted that, curiously and confusingly coincident with the frequency dependent delay, the Crab Pulsar also underwent an unusual slowing down, which they believed to be unrelated to the Crab Nebula and instead intrinsic to the Crab Pulsar, resulting in an additional delay that was frequency independent. However, it now appears that one of the groups attributes the frequency independent delay also to refractive effects. This work aims to verify whether at least a part of the frequency independent delay is indeed due to intrinsic slowing down of the Crab Pulsar. Timing analysis of the Crab Pulsar's October 1997 event has been done in X-rays, which are not delayed by the refractive and diffractive effects that affect radio waves; at X...

  9. Levels of Cadmium in White and Brown Meat of Warty Crab (Eriphia verrucosa).

    Science.gov (United States)

    Ariano, A; Voi, A Lo; D'Ambola, M; Marrone, R; Cacace, D; Severino, L

    2015-12-01

    European Union regulations that establish the maximum cadmium (Cd) levels for crab take into account only concentrations found in crab muscle (white meat), mainly from appendages; therefore, other organs and tissues (brown meat) are excluded. The objective of the present study was to evaluate Cd levels in both white and brown crab meat, in order to achieve a more complete assessment of health risk related to human consumption of warty crab. Microwave digestion and atomic absorption spectrometry were used to determine Cd concentrations in warty crab (Eriphia verrucosa) samples collected from the southern Tyrrhenian Sea in Italy. Cd concentrations in all samples of white crab meat were found to be very low (below the limit of quantification), although brown crab meat showed significantly higher Cd concentrations (up to 5.629 mg/kg wet weight; mean value, 1.465 mg/kg). Thus, the consumption of brown meat, common among certain populations of the Mediterranean region, where whole crustaceans are traditionally eaten, substantially increased Cd intake, resulting in alarmingly high estimated weekly intake values.

  10. Timing and route of migration of mature female blue crabs in a tidal estuary.

    Science.gov (United States)

    Eggleston, David B; Millstein, Erika; Plaia, Gayle

    2015-05-01

    Information on migration patterns is critical to using no-take migratory corridors and marine reserves to protect the spawning stock of commercially exploited species. Both active and passive acoustic tracking methods quantified movement of commercially and ecologically important blue crabs in the White Oak River estuary, NC, USA. We targeted post-mating female crabs migrating down-estuary to oceanic spawning grounds. Crabs travelled approximately 14.1 km mainly in deeper channels and over 12-26 days from mating areas to spawning grounds. No crabs were detected migrating down-estuary in the autumn and only 30% were detected migrating down-estuary in spring. None of the crabs detected near spawning grounds were detected or recaptured back up-estuary, suggesting that they either (i) do not return to the estuary after a one to two week period in the spawning area or (ii) were captured by fishermen. The results from this study demonstrate that (1) acoustic transmitters coupled with passive acoustic receivers provided reliable and valuable data on migration patterns of mature female blue crabs and (2) mature female blue crabs are capable of migrating primarily within deep channels to spawning grounds shortly after insemination.

  11. Uptake and survival of enteric viruses in the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Hejkal, T W; Gerba, C P

    1981-01-01

    Uptake of poliovirus 1 by the blue crab, Callinectes sapidus, was measured to assess the likelihood of contamination by human enteric viruses. Virus was found in all parts of the crab within 2 h after the crab was placed in contaminated artificial seawater. The highest concentrations of virus were found in the hemolymph and digestive tract, but the meat also contained virus. The concentration of virus in the crabs was generally less than in the surrounding water. Changes in salinity did not substantially affect the rate of accumulation. An increase in temperature from 15 to 25 degrees C increased the rates of both uptake and removal. Poliovirus survived up to 6 days in crabs at a temperature of 15 degrees C and a salinity of 10 g/kg. When contaminated crabs were boiled, 99.9% of poliovirus 1, simian rotavirus SA11, and a natural isolate of echovirus 1 were inactivated within 8 min. These data demonstrate that viruses in crabs should not pose a serious health hazard if recommended cooking procedures are used. PMID:6261683

  12. Utilization of waste crab shell (Scylla serrata) as a catalyst in palm olein transesterification.

    Science.gov (United States)

    Boey, Peng-Lim; Maniam, Gaanty Pragas; Hamid, Shafida Abd

    2009-01-01

    Aquaculture activity has increased the population of crab, hence increasing the generation of related wastes, particularly the shell. In addition, the number of molting process in crabs compounds further the amount of waste shell generated. As such, in the present work, the application of the waste crab shell as a source of CaO in transesterification of palm olein to biodiesel (methyl ester) was investigated. Preliminary XRD results revealed that thermally activated crab shell contains mainly CaO. Parametric study has been investigated and optimal conditions were found to be methanol/oil mass ratio, 0.5:1; catalyst amount, 4 wt. %; and reaction temperature, 338 K. As compared to laboratory CaO, the catalyst from waste crab shell performs well, thus creating another low-cost catalyst source for producing biodiesel as well as adding value to the waste crab shell. Reusability of crab shell CaO has also been studied and the outcome confirmed that the catalyst is capable to be reutilized up to 11 times, without any major deterioration.

  13. Summary of CARE-HHH Mini-Workshop on LHC Crab Cavity Validation, 21 August 2008

    CERN Document Server

    Calaga, R; Garoby, R; Linnecar, T; Tomás, R; Zimmermann, F; CERN. Geneva. BE Department

    2008-01-01

    A global LHC crab-cavity collaboration is rapidly advancing the R&D of a complete crab cavity cryomodule and performing the associated beam dynamics simulations compatible with a prototype test in the phase 0/I upgrade with the aim of establishing a full crab crossing scheme for the phase II upgrade of the LHC. A one day CARE-HHH mini-workshop was held on August 21, 2008 at CERN to discuss crab crossing in the LHC phase 0/I & II upgrades and this reports summarizes the activities of the four sessions that took place during the workshop. The goals of this crab-cavity workshop were fourfold: (1) to discuss prospects of crab cavities in LHC upgrades (2) to review the status of the cryomodule development and beam dynamics, (3) to establish validity requirements for LHC crab cavities which need to be demonstrated prior to their installation into the LHC, and (4) to provide guidance & coordination for the global collaborators.

  14. Lack of transmission of Hematodinium sp. in the blue crab Callinectes sapidus through cannibalism.

    Science.gov (United States)

    Li, Caiwen; Wheeler, Kersten N; Shields, Jeffrey D

    2011-10-06

    Hematodinium spp. are parasitic dinoflagellates of marine crustaceans. Outbreaks of Hematodinium sp. have impacted commercial landings of the blue crab Callinectes sapidus in the coastal bays of Virginia and Maryland (USA), with seasonal peaks in prevalence reaching 85%. The life cycle and transmission routes of the parasite in blue crabs are poorly understood. Cannibalism and waterborne transmission may be routes of transmission, although little conclusive evidence has been reported for these modes. We examined cannibalism as a route by a series of experiments wherein we repeatedly fed adult and juvenile crabs the tissues of crabs infected with Hematodinium. In each experiment, feeding was done 3 times over the course of 1 wk. Only 2 of 120 crabs were infected within 7 to 9 d after feeding, and these 2 were likely infected prior to the experimental exposures. Crabs inoculated with hemolymph from infected donors served as positive controls. They developed infections over 11 to 21 d, indicating that the Hematodinium sp. used in the cannibalism trials was infectious at the time of inoculation. Because amphipods also harbor Hematodinium-like infections, we fed tissues of infected crabs to the estuarine amphipod Leptocheirus plumulosus. Hematodinium DNA was detected in amphipods shortly after feeding, but not in animals held for longer periods, nor was it observed in histological preparations. Amphipods did not obtain infections by scavenging infected crab tissues. Our results show that Hematodinium sp. is not effectively transmitted through ingestion of diseased tissues, indicating that cannibalism may not be a major route of transmission for Hematodinium sp. in blue crabs.

  15. Molecular keys unlock the mysteries of variable survival responses of blue crabs to hypoxia.

    Science.gov (United States)

    Bell, Geoffrey W; Eggleston, David B; Noga, Edward J

    2010-05-01

    Hypoxia is a major stressor in coastal ecosystems, yet generalizing its impacts on fish and shellfish populations across hypoxic events is difficult due to variability among individuals in their history of exposure to hypoxia and related abiotic variables, and subsequent behavioral and survival responses. Although aquatic animals have diverse physiological responses to cope with hypoxia, we know little about how inter-individual variation in physiological state affects survival and behavioral decisions under hypoxic conditions. Laboratory experiments coupled with molecular techniques determined how extrinsic factors (e.g., water body and temperature) and respiratory physiology (hemocyanin concentration and structure) affected survival and behavior of adult blue crabs (Callinectes sapidus) exposed to different levels of hypoxia over a 30-h time period. Nearly 100% of crabs survived the 1.3 mg dissolved oxygen (DO) l(-1) treatment (18.4% air saturation), suggesting that adult blue crabs are tolerant of severe hypoxia. Probability of survival decreased with increasing hypoxic exposure time, lower DO, and increasing temperature. Individual-level differences in survival correlated with water body and crab size. Crabs collected from the oligo/mesohaline and hypoxic Neuse River Estuary (NRE), North Carolina, USA survived hypoxic exposures longer than crabs from the euhaline and normoxic Bogue and Back Sounds, North Carolina. Furthermore, small NRE crabs survived longer than large NRE crabs. Hemocyanin (Hcy) concentration did not explain these individual-level differences, however, hypoxia-tolerant crabs had Hcy structures indicative of a high-O(2)-affinity form of Hcy, suggesting Hcy "quality" (i.e., structure) may be more important for hypoxia survival than Hcy "quantity" (i.e., concentration). The geographic differences in survival we observed also highlight the importance of carefully selecting experimental animals when planning to extrapolate results to the population

  16. Interspecific hybridization and mitochondrial introgression in invasive carcinus shore crabs.

    Directory of Open Access Journals (Sweden)

    John A Darling

    Full Text Available Interspecific hybridization plays an important role in facilitating adaptive evolutionary change. More specifically, recent studies have demonstrated that hybridization may dramatically influence the establishment, spread, and impact of invasive populations. In Japan, previous genetic evidence for the presence of two non-native congeners, the European green crab Carcinus maenas and the Mediterranean green crab C. aestuarii, has raised questions regarding the possibility of hybridization between these sister species. Here I present analysis based on both nuclear microsatellites and the mitochondrial cytochrome C oxidase subunit I (COI gene which unambiguously argues for a hybrid origin of Japanese Carcinus. Despite the presence of mitochondrial lineages derived from both C. maenas and C. aestuarii, the Japanese population is panmictic at nuclear loci and has achieved cytonuclear equilibrium throughout the sampled range in Japan. Furthermore, analysis of admixture at nuclear loci indicates dramatic introgression of the C. maenas mitochondrial genome into a predominantly C. aestuarii nuclear background. These patterns, along with inferences drawn from the observational record, argue for a hybridization event pre-dating the arrival of Carcinus in Japan. The clarification of both invasion history and evolutionary history afforded by genetic analysis provides information that may be critically important to future studies aimed at assessing risks posed by invasive Carcinus populations to Japan and the surrounding region.

  17. Observations of Giant Pulses of the Crab Pulsar

    Institute of Scientific and Technical Information of China (English)

    Ling-Jun Kong; Ali Esamdin; Cheng-Shi Zhao; Zhi-Yong Liu; Jian-Ping Yuan

    2008-01-01

    The Crab Pulsar was observed at 1540 MHz with the 25m radio telescope at Urumqi with a filterbank de-dispersion backend. A total of 2436 giant pulses with pulse energies larger than 4300 Jy μs were detected in two observing sets. All of these giant pulses are located in the main pulse (MP) and inter pulse (IP) windows of the average profile of the Crab Pulsar. The ratio of the numbers of giant pulses detected in the IP and MP windows is about 0.05. Our results show that, at 1540 MHz, the emission in the IP is contributed by giant and normal pulses, while that in the MP is almost dominated by giant pulses. The distribution of energy of the 2436 giant pulses at 1540 MHz can be described by a power-law with index α=3.13±0.09. The intrinsic threshold of giant pulse energy in the MP window is about 1400 Jy μs at 1540 MHz.

  18. OBSERVATIONS OF THE CRAB NEBULA'S ASYMMETRICAL DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Loll, A. M.; Desch, S. J.; Scowen, P. A. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States); Foy, J. P., E-mail: allison.loll@asu.edu [Barrett, The Honors College, Arizona State University, P.O. Box 871612, Tempe, AZ 85287 (United States)

    2013-03-10

    We present the first Hubble Space Telescope Wide Field Planetary Camera-2 imaging survey of the entire Crab Nebula, in the filters F502N ([O III] emission), F673N ([S II]), F631N ([O I]), and F547M (continuum). We use our mosaics to characterize the pulsar wind nebula (PWN) and its three-dimensional structure, the ionizational structure in the filaments forming at its periphery, the speed of the shock driven by the PWN into surrounding ejecta (by inferring the cooling rates behind the shock), and the morphology and ionizational structure of the Rayleigh-Taylor (R-T) fingers. We quantify a number of asymmetries between the northwest (NW) and southeast (SE) quadrants of the Crab Nebula. The lack of observed filaments in the NW, and our observations of the spatial extent of [O III] emission lead us to conclude that cooling rates are slower, and therefore the shock speeds are greater, in the NW quadrant of the nebula, compared with the SE. We conclude that R-T fingers are longer, more ionizationally stratified, and apparently more massive in the NW than in the SE, and the R-T instability appears more fully developed in the NW.

  19. JITTER RADIATION MODEL OF THE CRAB GAMMA-RAY FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Teraki, Yuto; Takahara, Fumio, E-mail: teraki@vega.ess.sci.osaka-u.ac.jp [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)

    2013-02-15

    The gamma-ray flares of the Crab nebula detected by the Fermi and AGILE satellites challenge our understanding of the physics of pulsars and their nebulae. The central problem is that the peak energy of the flares exceeds the maximum energy E {sub c} determined by synchrotron radiation loss. However, when turbulent magnetic fields exist with scales {lambda}{sub B} smaller than 2{pi}mc {sup 2}/eB, jitter radiation can emit photons with energies higher than E {sub c}. The scale required for the Crab flares is about two orders of magnitude less than the wavelength of the striped wind. We discuss a model in which the flares are triggered by plunging the high-density blobs into the termination shock. The observed hard spectral shape may be explained by the jitter mechanism. We make three observational predictions: first, the polarization degree will become lower in flares; second, no counterpart will be seen in TeV-PeV range; and third, the flare spectrum will not be harder than {nu}F {sub {nu}}{proportional_to}{nu}{sup 1}.

  20. Chandra X-Ray Observatory Image of Crab Nebula

    Science.gov (United States)

    1999-01-01

    After barely 2 months in space, the Chandra X-Ray Observatory (CXO) took this sturning image of the Crab Nebula, the spectacular remains of a stellar explosion, revealing something never seen before, a brilliant ring around the nebula's heart. The image shows the central pulsar surrounded by tilted rings of high-energy particles that appear to have been flung outward over a distance of more than a light-year from the pulsar. Perpendicular to the rings, jet-like structures produced by high-energy particles blast away from the pulsar. Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous x-ray images have shown the outer parts of the jet and hinted at the ring structure. With CXO's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with CXO's Advanced Charge-Coupled Device (CCD) Imaging Spectrometer (ACIS) and High Energy Transmission Grating. The Crab Nebula, easily the most intensively studied object beyond our solar system, has been observed using virtually every astronomical instrument that could see that part of the sky

  1. PoGOLite measurement of Crab polarisation and future plans

    Science.gov (United States)

    Pearce, Mark

    2016-07-01

    (For the PoGOLite Collaboration) The PoGOLite Pathfinder is a balloon-borne hard X-ray polarimeter designed for the observation of bright, ~1 Crab, sources. Polarisation is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an BGO anticoincidence well. The PoGOLite Pathfinder was launched from the SSC Esrange Space Centre in July 2013 resulting in a near-circumpolar flight of two weeks duration. The linear polarisation of hard X-ray emissions from the Crab was measured in a previously unexplored energy interval, 20-120 keV. The polarimetric response was characterised prior to flight using both polarised and unpolarised calibration sources. Systematic effects were addressed through observations of a background field. An upgraded polarimeter, PoGO+, is scheduled to fly in summer 2016 from Esrange. Results from the 2013 Pathfinder flight and prospects for the 2016 flight will be discussed.

  2. A transcriptome analysis of mitten crab testes (Eriocheir sinensis

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2011-01-01

    Full Text Available The identification of expressed genes involved in sexual precocity of the mitten crab (Eriocheir sinensis is critical for a better understanding of its reproductive development. To this end, we constructed a cDNA library from the rapid developmental stage of testis of E. sinensis and sequenced 3,388 randomly picked clones. After processing, 2,990 high-quality expressed sequence tags (ESTs were clustered into 2,415 unigenes including 307 contigs and 2,108 singlets, which were then compared to the NCBI non-redundant (nr protein and nucleotide (nt database for annotation with Blastx and Blastn, respectively. After further analysis, 922 unigenes were obtained with concrete annotations and 30 unigenes were found to have functions possibly related to the process of reproduction in male crabs - six transcripts relevant to spermatogenesis (especially Cyclin K and RecA homolog DMC1, two transcripts involved in nuclear protein transformation, two heat-shock protein genes, eleven transcription factor genes (a series of zinc-finger proteins, and nine cytoskeleton protein-related genes. Our results, besides providing valuable information related to crustacean reproduction, can also serve as a base for future studies of reproductive and developmental biology.

  3. POSSIBILITIES OF CULTURING BIG SEA CRABS (LOBSTERS, SPINY LOBSTERS

    Directory of Open Access Journals (Sweden)

    Ivančica Strunjak-Perović

    1999-09-01

    Full Text Available By the end of the 19 th century an experimental work on culturing big sea crabs began in Europe and North America. Great demand for their flesh as well as their high price urged many institutions to explore the possibilities of a commercial production in varios parts of the world. Lobsters (Homarus sp. were mainly used for experimenting, so that the most data available refer to them. Because of the complicated larva stage spiny lobster culturing is mainly being carried out in experimental circumstances. Despite the promissing results this aquacultural activity faces many problems (long time until they achieve a commercial size, loss of eggs due to stress sensitivity during the process of moulting, canibalism. In order to minimize these problems various researches are being carried out, like temperature influence, influence of light, way of feeding, hormonal regulation of moulting frequency. Although both lobster and spiny lobsters live in the Adriatic Sea, there are no data on their culturing in our contry. Concernig conditions in our sea there are realistic possibilities for crabs production development. In this way this delicacy would be more affordable to broader population and could be a highly rated export product.

  4. Physicochemical and biofunctional properties of crab chitosan nanoparticles.

    Science.gov (United States)

    Nguyen, The Han; Kwak, Hae Soo; Kim, Sang Moo

    2013-08-01

    The physicochemical and biofunctional properties of crab chitosan nanoparticles of two different sizes (Nano A and B) manufactured by dry milling method were evaluated for commercialization. The deacetylation degrees (DD) of Nano A, B and the control chitosan were 90.9, 93.0, and 92.7% respectively whereas their molecular weights (M(w)) were 43.9, 44.7 and 208.8 kDa. The average sizes of the dispersed Nano A, B and the control chitosan in cetyltrimethylammonium chloride were 735.9, 849.4 and 2,382.4 nm, respectively, which were lower than 1441.7, 2935.6 and 6832.9 nm of the intact chitosans. Chitosan nanoparticles had mild tyrosinase, antioxidant and angiotensin I converting enzyme (ACE), but weak collagenase, elastase and beta-glucuronidase inhibitory activity. However, Nano A had strong alpha-glucosidase inhibitory activity, which was comparable to that of acarbose, a commercial alpha-glucosidase inhibitor. In addition, the minimum inhibitory concentrations (MICs) of chitosan and its nanoparticles ranged from 30 to > 200 microg/mL against each four gram-positive and gram-negative bacteria. Therefore, crab chitosan nanoparticles could be used as a nutraceutical, cosmeceutical or pharmaceutical product.

  5. Featured Image: A Detailed Look at the Crab Nebula

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    Planning on watching fireworks tomorrow? Heres an astronomical firework to help you start the celebrations! A new study has stunningly detailed the Crab Nebula (click for a closer look), a nebula 6,500 light-years away thought to have been formedby a supernova explosion and the subsequent ultrarelativistic wind emitted by the pulsar at its heart. Led by Gloria Dubner (University of Buenos Aires), the authors of this study obtained new observations of the Crab Nebula from five different telescopes. They compiled these observations to compare the details of the nebulas structure across different wavelengths, which allowedthem to learnabout the sources of various features within the nebula. In the images above, thetop left shows the 3 GHz data from the Very Large Array (radio). Moving clockise, the radio data (shown in red) is composited with: infrared data from Spitzer Space Telescope, optical continuum from Hubble Space Telescope, 500-nm optical datafrom Hubble, and ultraviolet data from XMM-Newton. The final two images are of the nebula center, and they are composites of the radio imagewith X-ray data from Chandra and near-infrared data from Hubble. To read more about what Dubner and collaborators learned (and to see more spectacular images!), check out the paper below.CitationG. Dubner et al 2017 ApJ 840 82. doi:10.3847/1538-4357/aa6983

  6. Nutritional quality and safety of cooked edible crab (Cancer pagurus).

    Science.gov (United States)

    Maulvault, Ana Luísa; Anacleto, Patrícia; Lourenço, Helena Maria; Carvalho, Maria Luísa; Nunes, Maria Leonor; Marques, António

    2012-07-15

    Edible crab (Cancer pagurus) is one of the most important crustaceans consumed in Southern European countries, either as boiled or steamed cooked product. So far, the majority of studies assessing health benefits and risks associated to seafood consumption have been carried out in raw products, despite being generally cooked before consumption, and mostly in muscle tissue. Therefore, the aim of this study was to assess the effect of steaming and boiling on the chemical safety and nutritional value of C. pagurus caught in spring and summer. Generally, chemical and elemental composition of brown meat (tissue in the body cavity comprising mainly gonads and hepatopancreas) differed significantly from muscle (white meat in claws and legs). Additionally, the same tissue revealed differences in chemical and elemental composition of raw and cooked C. pagurus, likely due to water leaching. In contrast, few variations between seasons were observed. The results revealed that the consumption of cooked edible crab muscle should be promoted, whereas brown meat ingestion should be done parsimoniously.

  7. Chinese mitten crab surveys of San Joaquin River basin and Suisun Marsh, California, 2000

    Science.gov (United States)

    May, Jason T.; Brown, Larry R.

    2001-01-01

    Juvenile Chinese mitten crabs (Eriocheir sinensis) are known to use both brackish and freshwater habitats as rearing areas. The objectives of this study were to examine the habitat use and potential effects of mitten crabs in the freshwater habitats of the San Joaquin River drainage up-stream of the Sacramento-San Joaquin Delta. After several unsuccessful attempts to catch or observe mitten crabs by trapping, electrofishing, and visual observations, the study was redirected to determine the presence of crabs in the San Joaquin River (in the vicinity of Mossdale) and Suisun Marsh. Monthly surveys using baited traps in the San Joaquin River were done from June through November 2000 and in the Suisun Marsh from August through October 2000. No mitten crabs were caught in the San Joaquin River Basin and only one mitten crab was caught in Suisun Marsh. Surveys were conducted at 92 locations in the San Joaquin River Basin by deploying 352 traps for 10,752 hours of trapping effort; in Suisun Marsh, 34 locations were investigated by deploying 150 traps for 3,600 hours of trapping effort. The baited traps captured a variety of organisms, including catfishes (Ictularidae), yellowfin gobies (Acantho-gobius flavimanus), and crayfish (Decapoda). It is unclear whether the failure to capture mitten crabs in the San Joaquin River Basin and Suisun Marsh was due to ineffective trapping methods, or repre-sents a general downward trend in populations of juvenile mitten crabs in these potential rearing areas or a temporary decline related to year-class strength. Available data (since 1998) on the number of mitten crabs entrained at federal and state fish salvage facilities indicate a downward trend in the number of crabs, which may indicate a declining trend in use of the San Joaquin River Basin by juvenile mitten crabs. Continued monitoring for juvenile Chinese mitten crabs in brackish and freshwater portions of the Sacramento-San Joaquin River Basins is needed to better assess the

  8. Intraspecific shape variation in horseshoe crabs: the importance of sexual and natural selection for local adaptation

    DEFF Research Database (Denmark)

    Faurby, Søren; Nielsen, Kasper Sauer Kollerup; Bussarawit, Somchai

    2011-01-01

    A morphometric analysis of the body shape of three species of horseshoe crabs was undertaken in order to infer the importance of natural and sexual selection. It was expected that natural selection would be most intense, leading to highest regional differentiation, in the American species Limulus...... polyphemus, which has the largest climatic differences between different populations. Local adaptation driven by sexual selection was expected in males but not females because horseshoe crab mating behaviour leads to competition between males, but not between females. Three hundred fifty-nine horseshoe crabs...

  9. Beam losses due to abrupt crab cavity failures in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B.; Zimmermann, F.

    2011-03-28

    A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.

  10. EFFECTS OF FISHES ON THE GROWTH AND SURVIVAL OF CHINESE MITTEN CRAB, ERIOCHEIR SINENSIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This experiment on the effects of fishes (Pelteobagrus fulvidraco, Channa argus, Cyprinus carpio) on growth and survival of juvenile Chinese mitten crab, Eriocheir sinensis was conducted in cages placed in Bao'an Lake. T-tests showed that effects of fishes on the carapace width growth were not significant as compared with the control (no fish). But the effects of these fishes on crab survival were negative. The causes of negative effects of fishes on crab survival were simply discussed on the basis of food habits.

  11. Heat shock response of the blue crab Portunus pelagicus:thermal stress and acclimation

    Institute of Scientific and Technical Information of China (English)

    Suhaila Qari

    2014-01-01

    Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus (P. pelagicus) as well as the time course of the changes in CTMax post heat shock. Methods: Crabs P. pelagicus were held in laboratory aquaria in tanks, which were supplied with filtered and aerated seawater. Crabs were acclimated at 20 °C, 25 °C, 30 °C and 35 °C for 3 weeks before their CTMax was determined. The CTMax was recorded for each crab as the median temperature during the 5 min period when a crab was not able to right itself, the average CTMax was calculated. The effect of heat shock on subsequent CTMax was measured. Crabs were heat shocked at temperature 1 °C lower than the CTMax for 20 min, followed by either 0.5 h, 1 h or 1.5 h recovery at 20 °C. The same procedure was repeated at other acclimation temperatures (25 °C, 30 °C and 35 °C). Results: Temperature acclimation of P. pelargicus from 20-35 °C progressively increased the CTMax. Acclimation at 35 °C the CTMax was 42.66 °C, whereas acclimation at 20 °C the CTMax was 39.8 °C. In P. pelagicus acclimated, at 20 °C the CTMax values after heat shock were significantly higher than crabs in control for 30 min, 1 h and 1.5 h after heat shock. In the 25 °C and 30 °C acclimated crabs, the CTMax values after heat shock were significantly higher than control only in 30 min and 1 h after heat shock. No significant differences in 35 °C acclimated crabs between control and heat shocked crabs were found after recovery for 30 min, 1 h, or 1.5 h. Conclusions: Heat shock caused significant rises in the CTMax, however, this increase was progressively reduced with longer recovery times at the acclimation temperature. For 20 °C acclimated crabs, the increased CTMax was still evident after 90 min, but for 25 °C and 30 °C crabs, the response was over after 90 min. Heat shock of 35 °C crabs was problematical, the CTMax gave no increased thermotolerance. It must be concluded that the

  12. No barrier to emergence of bathyal king crabs on the Antarctic shelf

    DEFF Research Database (Denmark)

    Aronson, Richard B.; Smith, Kathryn E.; Vos, Stephanie C.;

    2015-01-01

    showed that abundant, predatory king crabs comprise a reproductively viable population at 841- to 2,266-m depth. Depth profiles of temperature, salinity, habitat structure, food availability, and predators indicate that there are no barriers to prevent king crabs from moving upward onto the outer shelf...... at 400–550 m. A cold-water barrier above 200 m could be breached within the next few decades. Emergence of king crabs on the shelf could have catastrophic consequences for the unique seafloor communities of Antarctica....

  13. Beam losses due to abrupt crab cavity failures in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B.; Zimmermann, F.

    2011-03-28

    A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.

  14. Design of Electron and Ion Crabbing Cavities for an Electron-Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Alejandro Castilla Loeza, Geoffrey Krafft, Jean Delayen

    2012-07-01

    Beyond the 12 GeV upgrade at the Jefferson Lab a Medium Energy Electron-Ion Collider (MEIC) has been considered. In order to achieve the desired high luminosities at the Interaction Points (IP), the use of crabbing cavities is under study. In this work, we will present to-date designs of superconducting cavities, considered for crabbing both ion and electron bunches. A discussion of properties such as peak surface fields and higher-order mode separation will be presented. Keywords: super conducting, deflecting cavity, crab cavity.

  15. Detection of Paragonimus mexicanus (Trematoda) metacercariae in crabs from Oaxaca, Mexico.

    Science.gov (United States)

    Vargas-Arzola, Jaime; Segura-Salvador, Aristeo; Reyes-Velasco, Leobardo; Díaz-Chiguer, Dylan L; Márquez-Navarro, Adrián; León-Avila, Gloria; Ibañez-Cervantes, Gabriela; Camacho, Alejandro D; Sánchez-Manzano, Rosa Ma; Nogueda-Torres, Benjamín

    2014-09-01

    Metacercariae of Paragonimus mexicanus were collected in crabs Tehuana guerreroensis (Rathbun, 1933) in the municipality of Putla, Oaxaca, Mexico. Metacercariae were found in 20.8% of the crabs collected, with an average of 1.9 metacercarie per crab. Stained metacercariae showed the specific characteristics of P. mexicanus by morphology and sequencing a fragment of the 28S ribosomal gene obtained by PCR. These findings reveal that T. guerreroensis is an intermediate host for P. mexicanus; this new report is relevant considering the potential risk of transmission in the states of Oaxaca and Guerrero, Mexico.

  16. Extracellular digestion during hyposaline exposure in the Dungeness crab, Cancer magister, and the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Curtis, Daniel L; van Breukelen, Frank; McGaw, Iain J

    2013-12-01

    Extracellular digestive processes were examined in the Dungeness crab, Cancer magister and the blue crab, Callinectes sapidus, during hyposaline exposure. Both species are found in estuaries as adults, but vary in their ability to balance the cardiovascular and respiratory demands of concurrent osmoregulation and digestion. The weak osmoregulator, C. magister, is unable to balance the demands of osmoregulation and digestion. Concordant with observed decreases in oxygen consumption and mechanical digestion, proteolytic digestion within the foregut and hepatopancreas was delayed, resulting in a relative reduction of circulating amino acids post-feeding in low salinity. In contrast, the efficient osmoregulator, C. sapidus, balances the demands of osmoregulation and digestion, and mechanical digestion continues unabated in low salinity. Protease activity in the gut fluid and hepatopancreas showed either no change or a reduction over time. The transport of amino acids into the cells post-feeding is opposed by an efflux of amino acids at the cellular level, and resulted in a build up of amino acids in the hemolymph. Despite differences in the extracellular responses to low salinity exposure following feeding, both species were able to maintain high digestive efficiencies. © 2013.

  17. A crab swarm at an ecological hotspot: patchiness and population density from AUV observations at a coastal, tropical seamount

    Science.gov (United States)

    Cho, Walter; Starczak, Victoria; Govindarajan, Annette F.; Guzman, Héctor M.; Girdhar, Yogesh; Holleman, Rusty C.; Churchill, James; Singh, Hanumant; Ralston, David K.

    2016-01-01

    A research cruise to Hannibal Bank, a seamount and an ecological hotspot in the coastal eastern tropical Pacific Ocean off Panama, explored the zonation, biodiversity, and the ecological processes that contribute to the seamount’s elevated biomass. Here we describe the spatial structure of a benthic anomuran red crab population, using submarine video and autonomous underwater vehicle (AUV) photographs. High density aggregations and a swarm of red crabs were associated with a dense turbid layer 4–10 m above the bottom. The high density aggregations were constrained to 355–385 m water depth over the Northwest flank of the seamount, although the crabs also occurred at lower densities in shallower waters (∼280 m) and in another location of the seamount. The crab aggregations occurred in hypoxic water, with oxygen levels of 0.04 ml/l. Barcoding of Hannibal red crabs, and pelagic red crabs sampled in a mass stranding event in 2015 at a beach in San Diego, California, USA, revealed that the Panamanian and the Californian crabs are likely the same species, Pleuroncodes planipes, and these findings represent an extension of the southern endrange of this species. Measurements along a 1.6 km transect revealed three high density aggregations, with the highest density up to 78 crabs/m2, and that the crabs were patchily distributed. Crab density peaked in the middle of the patch, a density structure similar to that of swarming insects. PMID:27114859

  18. Mate locating and access behaviour of the parasitic pea crab, Nepinnotheres novaezelandiae, an important parasite of the mussel Perna canaliculus

    Directory of Open Access Journals (Sweden)

    Trottier Oliver

    2015-01-01

    Full Text Available Pea crabs are globally ubiquitous symbionts in the marine environment that cause serious economic impact in the aquaculture production of several major bivalve species. However, little is known about their host-parasite interactions, especially the mating behaviour of these parasites that could prove useful for controlling their infestation in aquaculture. In this study, the mate location behaviour of male New Zealand pea crabs, Nepinnotheres novaezelandiae (Filhol, 1885, was observed when dwelling in its preferred host, the commercially important green-lipped mussel, Perna canaliculus. Given the cryptic behaviour of the male crabs, a novel trapping system was developed to determine whether male crabs would exit their mussel hosts in response to an upstream female crab. The presence of receptive female crabs placed upstream successfully attracted 60% of male crabs from their host over 24 h. Observations of the nocturnal mate-finding behaviour of male crabs were made in darkness using infrared video recordings. Males spent on average 49 min on empty hosts and never left a mussel containing a female conspecific once found, spending 200 min on average to gain entry to the mussel. Male crabs were often observed stroking the mantle edge of the mussel whilst attempting to gain entry, successfully increasing mussel valve gape during entry from 3.7 to 5.5 mm. A pheromone-based mate location system is likely used by this crab to greatly reduce the risks associated with the location of females.

  19. Tissue distribution of hepatopancreatic parvo-like virus of shrimp in freshwater rice-field crab, Paratelphusa hydrodomous (Herbst).

    Science.gov (United States)

    Madan, N; Rajkumar, T; Sundar Raj, N; Farook, M A; Nambi, K S N; Abdul Majeed, S; Sahul Hameed, A S

    2014-11-01

    An attempt was made to determine the replication efficiency of hepatopancreatic parvo-like virus (HPV) of shrimp in different organs of freshwater rice-field crab Paratelphusa hydrodomous (Herbst) using bioassay, PCR, RT-PCR, ELISA, Western blot and q-PCR analyses. Another attempt was made to use this crab as an alternative to penaeid shrimp for the large-scale production of HPV. This crab was found to be highly susceptible to HPV by intramuscular injection. The systemic HPV infection was confirmed by PCR and Western blot analyses in freshwater crab. The expression of capsid protein gene in different organs of infected crab was revealed by RT-PCR analysis. Indirect ELISA was used to quantify the capsid protein in different organs of the crab. The copy number of HPV in different organs of the infected crab was quantified by q-PCR. The results revealed a steady decrease in CT values in different organs of the infected crab during the course of infection. The viral inoculum that was prepared from different organs of the infected crab caused significant mortality in post-larvae of tiger prawn, Penaeus monodon (Fabricius). The results revealed that this rice-field crab could be used as an alternative host for HPV replication and also for large-scale production of HPV.

  20. A crab swarm at an ecological hotspot: patchiness and population density from AUV observations at a coastal, tropical seamount

    Directory of Open Access Journals (Sweden)

    Jesús Pineda

    2016-04-01

    Full Text Available A research cruise to Hannibal Bank, a seamount and an ecological hotspot in the coastal eastern tropical Pacific Ocean off Panama, explored the zonation, biodiversity, and the ecological processes that contribute to the seamount’s elevated biomass. Here we describe the spatial structure of a benthic anomuran red crab population, using submarine video and autonomous underwater vehicle (AUV photographs. High density aggregations and a swarm of red crabs were associated with a dense turbid layer 4–10 m above the bottom. The high density aggregations were constrained to 355–385 m water depth over the Northwest flank of the seamount, although the crabs also occurred at lower densities in shallower waters (∼280 m and in another location of the seamount. The crab aggregations occurred in hypoxic water, with oxygen levels of 0.04 ml/l. Barcoding of Hannibal red crabs, and pelagic red crabs sampled in a mass stranding event in 2015 at a beach in San Diego, California, USA, revealed that the Panamanian and the Californian crabs are likely the same species, Pleuroncodes planipes, and these findings represent an extension of the southern endrange of this species. Measurements along a 1.6 km transect revealed three high density aggregations, with the highest density up to 78 crabs/m2, and that the crabs were patchily distributed. Crab density peaked in the middle of the patch, a density structure similar to that of swarming insects.

  1. Mode of action of dopamine in inducing hyperglycemia in the fresh water edible crab, Oziothelphusa senex senex.

    Science.gov (United States)

    Swetha, Ch; Sainath, S B; Reddy, P Sreenivasula

    2014-11-01

    The objective of this study was to investigate the mode of action of dopamine in regulating hemolymph sugar level in the fresh water edible crab, Oziothelphusa senex senex. Injection of dopamine produced hyperglycemia in a dose-dependent manner in intact crabs but not in eyestalkless crabs. Administration of dopamine resulted in a significant decrease in total carbohydrates and glycogen levels with a significant increase in glycogen phosphorylase activity levels in hepatopancreas and muscle of intact crabs, indicating dopamine-induced glycogenolysis resulting in hyperglycemia. Bilateral eyestalk ablation resulted in significant increase in the total carbohydrates and glycogen levels with a significant decrease in the activity levels of phosphorylase in the hepatopancreas and muscle of the crabs. Eyestalk ablation resulted in significant decrease in hemolymph hyperglycemic hormone levels. The levels of hyperglycemic hormone in the hemolymph of dopamine injected crabs were significantly higher than in control crabs. However, no significant changes in the levels of hemolymph hyperglycemic hormone and sugar and tissue carbohydrate and phosphorylase activity were observed in dopamine injected eyestalk ablated crabs when compared with eyestalk ablated crabs. These results support an earlier hypothesis in crustaceans that dopamine acts as a neurotransmitter and induces hyperglycemia by triggering the release of hyperglycemic hormone in the crab, O. senex senex. © 2014 Wiley Periodicals, Inc.

  2. A crab swarm at an ecological hotspot: patchiness and population density from AUV observations at a coastal, tropical seamount.

    Science.gov (United States)

    Pineda, Jesús; Cho, Walter; Starczak, Victoria; Govindarajan, Annette F; Guzman, Héctor M; Girdhar, Yogesh; Holleman, Rusty C; Churchill, James; Singh, Hanumant; Ralston, David K

    2016-01-01

    A research cruise to Hannibal Bank, a seamount and an ecological hotspot in the coastal eastern tropical Pacific Ocean off Panama, explored the zonation, biodiversity, and the ecological processes that contribute to the seamount's elevated biomass. Here we describe the spatial structure of a benthic anomuran red crab population, using submarine video and autonomous underwater vehicle (AUV) photographs. High density aggregations and a swarm of red crabs were associated with a dense turbid layer 4-10 m above the bottom. The high density aggregations were constrained to 355-385 m water depth over the Northwest flank of the seamount, although the crabs also occurred at lower densities in shallower waters (∼280 m) and in another location of the seamount. The crab aggregations occurred in hypoxic water, with oxygen levels of 0.04 ml/l. Barcoding of Hannibal red crabs, and pelagic red crabs sampled in a mass stranding event in 2015 at a beach in San Diego, California, USA, revealed that the Panamanian and the Californian crabs are likely the same species, Pleuroncodes planipes, and these findings represent an extension of the southern endrange of this species. Measurements along a 1.6 km transect revealed three high density aggregations, with the highest density up to 78 crabs/m(2), and that the crabs were patchily distributed. Crab density peaked in the middle of the patch, a density structure similar to that of swarming insects.

  3. A Lethal Virus of the Blue Crab Callinectes sapidus May Be Present Throughout its Trans-hemispheric Range

    Science.gov (United States)

    Schott, E. J.; Flowers, E. M.; Vinagre, A.; Brown, S.; Almeida, A.

    2016-02-01

    Blue crabs, Callinectes sapidus, are key epibenthic predators and support valuable fisheries throughout North and South America. On both continents, they are also used to produce soft shell crabs, a value added product. On the Atlantic coast of the USA, mortality of blue crabs in soft shell production is often 25% or greater. A majority of those crabs have been found to be infected with a reovirus lethal to blue crabs. The CsRV1 virus infects multiple ectodermal and mesodermal tissues and was first described as RLV (reo-like virus) in the late 1970s. However its potential for affecting large numbers of crabs was not fully recognized until 2010 when molecular methods were developed to study its prevalence in aquaculture and the wild. Using a sensitive Rt-qPCR assay for the virus, a multi-year survey of crabs from the mid-Atlantic USA coast and Chesapeake Bay revealed that approximately 20% of adult and juvenile crabs were positive for CsRV1 genomic RNA. If blue crabs in the wild die from CsRV1 infections as rapidly as captive infected crabs, it suggests that significant numbers of wild blue crabs die from CsRV1 infections. Crab fishery managers in the Chesapeake Bay recently recognized that there is a need to better understand the role of diseases in natural mortality. The CsRV1 virus is found in C. sapidus throughout the USA range, and has been discovered in diseased Brazilian C. sapidus from Rio Grande do Sul. Genetic analysis of the virus shows that strains of CsRV1 found in Brazil are distinct from the strains identified in the USA. This pan-hemispheric range suggests that the virus has long been a component of blue crab ecology. Much more study is needed to understand the history and impacts of CsRV1 throughout the USA, Brazil, and the vast coastline in between.

  4. Tolerance, bioenergetics, and biochemical composition of the blue crab, Callinectes sapidus rathbun, exposed to the water-soluble fraction of South Louisiana crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.Y.

    1986-01-01

    Blue crabs were highly tolerant to petroleum hydrocarbons. Rates of energy intake decreased with increasing hydrocarbon concentration. Although energy expenditure rates of crabs exposed to 2504 ppb were not significantly higher than that of control crabs, they were significantly higher than those of crabs exposed to 820 and 1476 ppb. Molting was delayed in crabs exposed to 1476 and 2504 ppb. Crab growth was significantly reduced in a dose-dependent manner. The correlation between scope for growth and tissue growth was highly significant, indicating a bioenergetic basis for the decreased growth in crabs exposed to petroleum hydrocarbons. RNA content of crabs exposed to crude oil was significantly reduced on all sampling dates. Protein content of crabs exposed to crude oil was lower than that of control crabs on days 14 and 21. DNA content was not significantly different from that of control crabs. RNA:DNA and protein:DNA ratio were significantly reduced in crabs exposed to crude oil. The significant correlations suggest the possibility of their use as indicators of physiological condition. Significant differences in lipid content and concentration were observed. Analysis of five lipid classes indicate that structural lipids were less affected than lipids used for energy storage among crabs exposed to crude oil. The observed changes growth pattern and biochemical composition suggest that the pattern of energy utilization was altered. Among crabs exposed to petroleum hydrocarbons, growth in size took place despite little increase in tissue content. Available energy was used for growth with little being stored in lipid reserves.

  5. Identification of a crab gill FXYD2 protein and regulation of crab microsomal Na,K-ATPase activity by mammalian FXYD2 peptide.

    Science.gov (United States)

    Silva, Elias C C; Masui, Douglas C; Furriel, Rosa P; McNamara, John C; Barrabin, Hector; Scofano, Helena M; Perales, Jonas; Teixeira-Ferreira, André; Leone, Francisco A; Fontes, Carlos Frederico L

    2012-11-01

    This investigation discloses the recognition of an FXYD2 protein in a microsomal Na,K-ATPase preparation from the posterior gills of the blue crab, Callinectes danae, by a mammalian (rabbit) FXYD2 peptide specific antibody (γC(33)) and MALDI-TOF-TOF mass spectrometry techniques. This is the first demonstration of an invertebrate FXYD2 protein. The addition of exogenous pig FXYD2 peptide to the crab gill microsomal fraction stimulated Na,K-ATPase activity in a dose-dependent manner. Exogenous pig FXYD2 also considerably increased enzyme affinity for K(+), ATP and NH(4)(+). K(0.5) for Na(+) was unaffected. Exogenous pig FXYD2 increased the V(max) for stimulation of gill Na,K-ATPase activity by Na(+), K(+) and ATP, by 30% to 40%. The crab gill FXYD2 is phosphorylated by PKA, suggesting a regulatory function similar to that known for the mammalian enzyme. The PKA-phosphorylated pig FXYD2 peptide stimulated the crab gill Na,K-ATPase activity by 80%, about 2-fold greater than did the non-phosphorylated peptide. Stimulation by the PKC-phosphorylated pig FXYD2 peptide was minimal. These findings confirm the presence of an FXYD2 peptide in the crab gill Na,K-ATPase and demonstrate that this peptide plays an important role in regulating enzyme activity. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Feeding and decoration preferences of the epialtidae crab Acanthonyx scutiforms

    Directory of Open Access Journals (Sweden)

    Marcelo Augusto Vasconcelos

    2009-06-01

    Full Text Available Studies on the feeding preferences of marine herbivores are very important for our better understanding of the biology and the ecological role of these organisms. Members of the family Epialtidae are usually herbivores that mask themselves with pieces of seaweed and other materials to avoid predation. In order to better understand the mechanisms of food and decorating choices of the decorator crab Acanthonyx scutiformis, two multiple-choice feeding assays were performed using fresh seaweeds and artificial food containing crude extracts of the four seaweeds Osmundaria obtusiloba, Plocamium brasiliense, Sargassum sp., and Dictyota menstrualis, offered simultaneously to this crab species. In both assays the seaweed most consumed was O. obtusiloba, followed by P. brasiliense and Sargassum sp., while D. menstrualis was the least consumed. It is suggested that A. scutiformis is a generalist feeder, but with some preference for the perennial red seaweed O. obtusiloba and the chemically-defended seaweed P. brasiliense. Decorating behavior observations revealed the preferences of A. scutiformis by P. brasiliense. This decorating behavior can be interpreted as a mechanism to avoid generalist predators, since feeding and decorating preference were not associated and the crab used only small pieces of chemically defended algae.Estudos sobre preferência alimentar de herbívoros marinhos são muito importantes para o melhor entendimento da importância biológica e ecológica destes organismos. Caranguejos majídeos são usualmente herbívoros que se camuflam com pedaços de macroalgas e outros materiais para evitar a predação. Para entender melhor os mecanismos de escolha de alimento e decoração do caranguejo decorador Acanthonyx scutiformis, foram realizados dois ensaios de múltipla escolha usando macroalgas frescas e alimentos artificiais contendo extratos brutos das macroalgas Osmundaria obtusiloba, Plocamium brasiliense, Sargassum sp. e Dictyota

  7. Using ssh as portal - The CMS CRAB over glideinWMS experience

    CERN Document Server

    Belforte, Stefano; Letts, James; Fanzago, Federica; Saiz Santos, Maria Dolores; Martin, Terrence

    2013-01-01

    The User Analysis of the CMS experiment is performed in distributed way usingboth Grid and dedicated resources. In order to insulate the users from the details of computing fabric, CMS relies on the CRAB (CMS Remote Analysis Builder) package as an abstraction layer. CMS has recently switched from a client-server version of CRAB to a purely client-based solution, with ssh being used to interface with HTCondor-based glideinWMS batch system. This switch has resulted in significant improvement of user satisfaction, as well as in significant simplification of the CRAB code base and of the operation support. This paper presents the architecture of the ssh-based CRAB package, the rationale behind it, as well as the operational experience running both the client-server and the ssh-based versions in parallel forseveral months.

  8. 76 FR 31941 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Horseshoe Crabs; Application...

    Science.gov (United States)

    2011-06-02

    ... National Oceanic and Atmospheric Administration RIN 0648-XW53 Atlantic Coastal Fisheries Cooperative Management Act Provisions; Horseshoe Crabs; Application for Exempted Fishing Permit AGENCY: National Marine... otherwise restricted by the regulations promulgated under the Atlantic Coastal Fisheries...

  9. Accumulation of contaminants from urban rainfall runoff in blue crabs: A pilot study

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objective of this pilot study was to determine the feasibility of using caged blue crabs Callinectes sapidus to monitor accumulation of contaminants in urban...

  10. Crab Orchard National Wildlife Refuge: Annual Narrative Report: Calender year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1994 calendar year. The report begins with a summary...

  11. Crab Orchard National Wildlife Refuge: Annual Narrative Report: Calender year 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1993 calendar year. The report begins with a summary...

  12. Crab Orchard National Wildlife Refuge: Annual Narrative Report: Calender year 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1995 calendar year. The report begins with a summary...

  13. Crab Orchard National Wildlife Refuge: Annual Narrative Report: Calender year 1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1996 calendar year. The report begins with a summary...

  14. Narrative report : September thru December, 1963. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1963. The report begins by...

  15. Crab Orchard National Wildlife Refuge : Law Enforcement Plan and Station Crowd Control Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Law Enforcement Plan clarifies U.S. Fish and Wildlife enforcement policies as they apply to the Refuge. It provides...

  16. Crab Orchard National Wildlife Refuge Annual narrative report: Calendar year 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1982 calendar year. The report begins by describing...

  17. Narrative report : May 1 thru August 31, 1962. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1962. The report begins by summarizing...

  18. Narrative report : May thru August, 1961. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1961. The report begins by summarizing...

  19. 78 FR 40696 - Proposed Information Collection; Comment Request; Alaska Crab Cost Recovery

    Science.gov (United States)

    2013-07-08

    ... National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Alaska Crab Cost Recovery AGENCY: National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION... on proposed and/or continuing information collections, as required by the Paperwork Reduction Act...

  20. Energy source in the developing eggs of the Indian horseshoe crab, Tachypleus gigas (Muller)

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Aguiar, Q.; Saldanha, C.

    Wet weight, dry weight, water content, ash weight, soluble and insoluble proteins, carbohydrates, lipids, and glycogen were determined from 0 to 40th day after fertilization of the developing eggs of the Indian horseshoe crab, Tachypleus gigas...

  1. AFSC/RACE/SAP/Cummiskey: Red king crab sonic tagging and dive database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is data from a long-term monitoring project which utilized sonic tags to follow aggregations of red king crab in Womens Bay near Kodiak Alaska. The database...

  2. Survey for contaminants in sediments in Pigeon Creek at Crab Orchard National Wildlife Refuge, Marion, Illinois

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A survey for environmental contaminants was conducted by the U.S. Fish and Wildlife Service personnel in 1986 which included several locations on Crab Orchard...

  3. Narrative report : January through April, 1962. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1962. The report begins by summarizing...

  4. Crab Orchard National Wildlife Refuge Narrative report : January thru April, 1959

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1959. The report begins by summarizing...

  5. Crab Orchard National Wildlife Refuge Narrative report : January thru April, 1958

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1958. The report begins by summarizing...

  6. Dry season distribution of land crabs, Gecarcinus quadratus (Crustacea: Gecarcinidae), in Corcovado National Park, Costa Rica.

    Science.gov (United States)

    Griffiths, Megan E; Mohammad, Basma A; Vega, Andres

    2007-03-01

    The land crab Gecarcinus quadratus is an engineering species that controls nutrient cycling in tropical forests. Factors regulating their coastal distribution are not fully understood. We quantified land crab distribution during the dry season at Sirena Field Station in Corcovado National Park, Costa Rica, and found that land crab burrow density decreases with increasing distance from the ocean. Leaf litter depth and tree seedling density are negatively correlated with land crab burrow density. Burrows are strongly associated with sand substrate and burrow density is comparatively low in clay substrate. Results suggest that G. quadratus is limited to a narrow coastal zone with sand substrate, and this distribution could have profound effects on plant community structure.

  7. Feeding behaviour and food selection in the horseshoe crab, Tachypleus gigas (Muller)

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A; Mishra, J.K.; Parulekar, A

    The Indian horseshoe crab, Tachypleus gigas, is a benthic feeder which subsists mainly on molluscs, decayed organic matter and polychaetes, in order of prevalence. A strong and positive preference was recorded for molluscs over other food organisms...

  8. Crab Orchard National Wildlife Refuge annual narrative report: Calendar year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1990 calendar year. The report begins with a...

  9. Crab burrows as conduits for groundwater-surface water exchange in Bangladesh

    Science.gov (United States)

    Stahl, Mason O.; Tarek, M. H.; Yeo, Darren C. J.; Badruzzaman, A. B. M.; Harvey, Charles F.

    2014-12-01

    Groundwater recharge affects water budgets and groundwater quality on the deltas and floodplains of South and Southeast Asia. Rain and flooding rivers recharge groundwater during the monsoon; irrigated rice fields and surface water bodies recharge aquifers during the dry season. Groundwater throughout the region is severely contaminated by arsenic, and recent research suggests that quantifying and characterizing recharge is important to understand whether recharge flushes or mobilizes arsenic from aquifers. At a field site in Bangladesh, we found that burrows of terrestrial crabs short-circuit low-permeability surface sediments, providing the primary conduit for recharge. We combine field observations along with a model that couples isotope and water balances to quantify the effect of crab burrows on aquifer recharge. Given the wide distribution of burrowing crabs and the surficial geology, we suggest that crab burrows provide widespread conduits for groundwater recharge.

  10. AFSC/RACE/SAP/Swiney: Red king crab fecundity and embryo and larval quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stock assessment of Alaskan red king crab, Paralithodes camtschaticus (Tilesius, 1815), can be improved by incorporating reproductive output, which requires an...

  11. Early life history studies of the king crab: A progress report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Describes a study where Alaska King Crabs were brought down from the Bering Sea and placed in outside rearing ponds at the State of Washington's Marine Research...

  12. NWHL Final Report 1983-84 Lead Poisoning Monitoring Program Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Lead poisoning was demonstrated to occur in Canada geese using Crab Orchard National Wildlife Refuge during the 1983-84 Lead Poisoning Monitoring Program. Necropsies...

  13. Crab Orchard National Wildlife Refuge annual narrative report: Calendar year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1989 calendar year. The report begins with a...

  14. Understanding to Hierarchical Microstructures of Crab (Chinese hairy) Shell as a Natural Architecture

    Energy Technology Data Exchange (ETDEWEB)

    Chuanqiang, Zhou [Testing Center, Yangzhou University, No. 48 Wenhui East Road, Yangzhou (China); Xiangxiang, Gong [Testing Center, Yangzhou University, No. 48 Wenhui East Road, Yangzhou (China); School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou (China); Jie, Han [School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou (China)

    2016-03-07

    This work was done to better understand the microstructures, composition and mechanical properties of Chinese hairy crab shell. For fully revealing its hierarchical microstructure, the crab shell was observed with electron microscope under different magnifications from different facets. XRD, EDS, FTIR and TGA techniques have been used to characterize the untreated and chemically-treated crab shells, which provided enough information to determine the species and relative content of components in this biomaterial. Combined the microstructures with constituents analysis, the structural principles of crab shell was detailedly realized from different structural levels beyond former reports. To explore the relationship between structure and function, the mechanical properties of shell have been measured through performing tensile tests. The contributions of organics and minerals in shell to the mechanical properties were also discussed by measuring the tensile strength of de-calcification samples treated with HCl solution.

  15. Crab Orchard National Wildlife Refuge Narrative report : September thru December, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1957. The report begins by...

  16. Narrative report : January thru April, 1960. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1960. The report begins by summarizing...

  17. Narrative report : September thru December, 1958. Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1958. The report begins by...

  18. Crab Orchard National Wildlife Refuge Narrative report : January thru April, 1947

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1947. The report begins by summarizing...

  19. More than one way to invade: lessons from genetic studies of Carcinus shore crabs

    Science.gov (United States)

    The European green crab Carcinus maenas is one of the world's most widely recognized marine invaders. The success of this species has provided opportunities to explore genetic patterns associated with establishment and population expansion following independent introduction event...

  20. Toxicity of oil and dispersed oil on juvenile mud crabs, Rhithropanopeus harrisii.

    Science.gov (United States)

    Anderson, Julie A; Kuhl, Adam J; Anderson, A Nikki

    2014-04-01

    In order to simulate an offshore oil spill event, we assessed the acute toxicity of the non-dispersed and the chemically dispersed water-accommodated fraction (WAF) of crude oil using Louisiana sweet crude and Corexit(®) 9500A with juvenile Harris mud crabs (Rhithropanopeus harrisii), an important Gulf of Mexico benthic crustacean. The chemical dispersion of crude oil significantly increased acute toxicity of the WAF in juvenile mud crabs compared to naturally dispersed oil. The majority of the mortality in the chemically dispersed treatments occurred within 24 h. While higher concentrations of chemically dispersed WAF had no survivors, at lower concentrations surviving juvenile crabs displayed no long-term effects. These results suggest that if the juvenile crabs survive initial exposure, acute exposure to dispersed or non-dispersed crude oil may not induce long-term effects.

  1. Larval spirurida (Nematoda) from the crab Macrophthalmus hirtipes in New Zealand

    DEFF Research Database (Denmark)

    Moravec, Frantisek; Fredensborg, Brian Lund; Latham, A David M;

    2003-01-01

    Previously undescribed third-stage larvae of two species of Spirurida were found in the haemocoel of the stalk-eyed mud crab Macrophthalmus hirtipes (Heller) (Ocypodidae) in New Zealand. Examinations by light and scanning electron microscopy showed that the larger larvae (about 7 mm long) belonged...... from Papanui Inlet, on Otago Peninsula, South Island, 74 crabs (90.2%) were infected with larval nematodes with an intensity of 1-18 (mean 4.6) nematodes per crab; no distinction between nematode species was made in these estimates, although juvenile Acuariidae greatly outnumbered larval Ascarophis....... Apparently, crabs play a role as intermediate hosts of these nematode species. This is the first record of larval representatives of Cystidicolidae and Acuariidae from invertebrates in the Australasian Region....

  2. Crab Orchard National Wildlife Refuge Narrative report : May thru August, 1958

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1958. The report begins by summarizing...

  3. Crab Orchard National Wildlife Refuge Narrative report : May through August, 1959

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1959. The report begins by summarizing the...

  4. Colonization of the gut of the blue crab (Callinectes sapidus) by Vibrio cholerae.

    Science.gov (United States)

    Huq, A; Huq, S A; Grimes, D J; O'Brien, M; Chu, K H; Capuzzo, J M; Colwell, R R

    1986-01-01

    Attachment of Vibrio cholerae to the mucosal surface of the intestine is considered to be an important virulence characteristic. Vibrio cholerae, an autochthonous member of brackish water and estuarine bacterial communities, also attaches to crustacea, a significant factor in multiplication and survival of V. cholerae in nature. The ability of V. cholerae to attach to the gut wall of the blue crab (Callinectes sapidus) was examined, and attachment was observed only in the hindgut and not the midgut of crabs, confirming a requirement for chitin in the attachment of V. cholerae to invertebrate and zooplankton surfaces. The new finding of attachment of V. cholerae to the hindgut of crabs may be correlated with the epidemiology and transmission of cholera in the aquatic environment. The crab model may also prove useful in elucidating the mechanism(s) of ion transport in crustacea. Images PMID:3767362

  5. Crab Orchard National Wildlife Refuge Narrative report : May through August, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1957. The report begins by...

  6. AFSC/RACE/GAP/Nichol: Archival tag depth and temperature data from snow crab

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seasonal migration of commercial-size (=102 mm carapace width [CW]), morphometrically mature (MM) snow crabs (Chionoecetes opilio) from the eastern Bering Sea was...

  7. Narrative report : September thru December, 1961. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1961. The report begins by...

  8. Crab Orchard National Wildlife Refuge : Annual narrative report: Calendar year 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1984 calendar year. The report begins with a...

  9. AFSC/RACE/GAP/Nichol: Archival tag depth and temperature data from red king crab

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In December of 2009, a total of 135 adult male red king crab (Paralithodes camtschaticus) were tagged with depth and temperature recording archival tags and released...

  10. Crab Orchard National Wildlife Refuge: Annual Narrative Report: Calender year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1992 calendar year. The report begins with a summary...

  11. Crab Orchard National Wildlife Refuge annual narrative report: Calendar year 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1991 calendar year. The report begins with a...

  12. CRAB3: Establishing a new generation of services for distributed analysis at CMS

    CERN Document Server

    Spiga, Daniele

    2012-01-01

    In CRAB3 all work is centrally injected and managed in a global queue. A pool of agents, which can be geographically distributed, consumes work from the central services, servicing the user tasks. The new gener...

  13. Pacific Remote Islands MNM: Initial Survey Instructions for Terrestrial Hermit Crabs

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Land-crabs in the genus Coenobita play an influential role in shaping the species composition and structure of the terrestrial community in the tropical Central...

  14. Impact of CRAB Symptoms in Survival of Patients with Symptomatic Myeloma in Novel Agent Era

    Science.gov (United States)

    Nakaya, Aya; Fujita, Shinya; Satake, Atsushi; Nakanishi, Takahisa; Azuma, Yoshiko; Tsubokura, Yukie; Hotta, Masaaki; Yoshimura, Hideaki; Ishii, Kazuyoshi; Ito, Tomoki; Nomura, Shosaku

    2017-01-01

    The acronym CRAB summarizes the most typical clinical manifestations of multiple myeloma, these being hypercalcemia, renal failure, anemia, and bone disease. CRAB can be used to distinguish between active, symptomatic multiple myeloma and monoclonal gammopathy of undermined significance or smoldering myeloma. The distinction is relevant not only for classification and diagnosis but also for therapy. CRAB factors influence the prognosis of multiple myeloma. However, it is unclear whether the presence of CRAB factors has an influence on the prognosis of myeloma treated with novel agents. In the current study, patients with hypercalcemia and bone disease showed a significantly worse prognosis, whereas anemia and renal failure showed no difference in survival. Novel agents used for treatment of patients with renal failure suggested a favorable outcome compared with conventional therapy. Bone disease was the most common factor and may have the strongest prognostic value in symptomatic myeloma patients using novel agents. PMID:28286629

  15. Narrative report : May through August, 1963. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1963. The report begins by summarizing the...

  16. Crab Orchard National Wildlife Refuge Narrative report : May 1 to August 31, 1947

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1947. The report begins by summarizing the...

  17. Crab Orchard National Wildlife Refuge Annual narrative report: Calendar year 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1978 calendar year. The report begins by describing...

  18. Mobile Acoustical Bat Monitoring Annual Summary Report CY 2013 to 2015 - Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These reports summarize bat calls collected along transects at Crab Orchard NWR between 2013 and 2015. Calls were classified using Bat Call ID ([BCID] version 2.5a)...

  19. AFSC/RACE/SAP/Munk: Life history studies of Tanner crab, Chionoecetes bairdi, near Kodiak, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — From 1994 through 2012 Tanner crab were identified as premolt, held through a molt, and then measured to determine growth per molt.

  20. 2000 Land Cover/ Land Use in the Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The The U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (USFWS) are collaborating to develop a Comprehensive Conservation Plan (CCP) for Crab...

  1. AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

  2. Narrative report : January thru April, 1961. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1961. The report begins by summarizing...

  3. Narrative report : May 1, thru August 31, 1960. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1960. The report begins by summarizing the...

  4. Crab Orchard National Wildlife Refuge: Comprehensive Conservation Plan and Environmental Assessment

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Crab Orchard National Wildlife Refuge for the next 15 years. This plan outlines the...

  5. Electric shock causes physiological stress responses in shore crabs, consistent with prediction of pain.

    Science.gov (United States)

    Elwood, Robert W; Adams, Laura

    2015-11-01

    Animal pain is defined by a series of expectations or criteria, one of which is that there should be a physiological stress response associated with noxious stimuli. While crustacean stress responses have been demonstrated they are typically preceded by escape behaviour and thus the physiological change might be attributed to the behaviour rather than a pain experience. We found higher levels of stress as measured by lactate in shore crabs exposed to brief electric shock than non-shocked controls. However, shocked crabs showed more vigorous behaviour than controls. We then matched crabs with the same level of behaviour and still found that shocked crabs had stronger stress response compared with controls. The finding of the stress response, coupled with previous findings of long-term motivational change and avoidance learning, fulfils the criteria expected of a pain experience.

  6. Crab Orchard National Wildlife Refuge Wilderness Character Monitoring Back-end Database

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is the back-end data file for the Crab Orchard Wilderness Character Monitoring Application. User interface and lookup databases are required for use (see...

  7. Crab Orchard National Wildlife Refuge : Annual narrative report: Calendar year 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1986 calendar year. The report begins with a...

  8. Narrative report : September 1 thru December 31, 1962. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1962. Wildlife- including...

  9. Narrative report : September thru December, 1959. Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1959. The report begins by...

  10. Narrative report : September thru December, 1960. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1960. The report begins by...

  11.  The diversity of horseshoe crabs - protecting an endangered resource

    DEFF Research Database (Denmark)

    Funch, Peter; Cong, Nguyen Van; Intanai, Itsara

    Horseshoe crabs are fascinating inhabitants of the sea represented by four living species, where three species live in Asia, while the fourth species lives on the East coast of North America. Ancient fossils, dating back to Ordovician 445 million years ago looks so similar to recent horseshoe crabs...... that people often call them "living fossils". Unfortunately, the existing populations are threatened by overfishing of the adults as well as by destruction and pollution of the beaches where they mate and deposit their eggs. All four extant species are on IUCN Red List of Threatened Species. The blue blood...... for eel and conch on the Atlantic Coast, and migrating shorebirds depend on their eggs for food. We recently initiated a research project to investigate and compare the physiology and genetic variation in all four species of horseshoe crabs worldwide. We intend to analyze the DNA of the horseshoe crabs...

  12. Acute fluoxetine exposure alters crab anxiety-like behaviour, but not aggressiveness.

    Science.gov (United States)

    Hamilton, Trevor James; Kwan, Garfield T; Gallup, Joshua; Tresguerres, Martin

    2016-01-25

    Aggression and responsiveness to noxious stimuli are adaptable traits that are ubiquitous throughout the animal kingdom. Like vertebrate animals, some invertebrates have been shown to exhibit anxiety-like behaviour and altered levels of aggression that are modulated by the neurotransmitter serotonin. To investigate whether this influence of serotonin is conserved in crabs and whether these behaviours are sensitive to human antidepressant drugs; the striped shore crab, Pachygrapsus crassipes, was studied using anxiety (light/dark test) and aggression (mirror test) paradigms. Crabs were individually exposed to acute doses of the selective serotonin reuptake inhibitor, fluoxetine (5 or 25 mg/L), commonly known as Prozac®, followed by behavioural testing. The high dose of fluoxetine significantly decreased anxiety-like behaviour but had no impact on mobility or aggression. These results suggest that anxiety-like behaviour is more sensitive to modulation of serotonin than is aggressiveness in the shore crab.

  13. Narrative report : January through April, 1963. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1963. The report begins by summarizing...

  14. Gender and snow crab occupational asthma in Newfoundland and Labrador, Canada.

    Science.gov (United States)

    Howse, Dana; Gautrin, Denyse; Neis, Barbara; Cartier, André; Horth-Susin, Lise; Jong, Michael; Swanson, Mark C

    2006-06-01

    Fish and shellfish processing employs many thousands of people globally, with shellfish processing becoming more important in recent years. Shellfish processing is associated with multiple occupational health and safety (OHS) risks. Snow crab occupational asthma (OA) is work-related asthma associated with processing snow crab. We present a gender analysis of findings from a 3-year multifaceted study of snow crab OA in Newfoundland and Labrador, Canada. The study was carried out in four snow crab processing communities between 2001 and 2004. An anonymous survey questionnaire on knowledge, beliefs, and concerns related to processing snow crab administered to 158 workers attending community meetings at the start of the research found that women were significantly more likely than men to associate certain health problems, especially chest tightness, difficulty breathing, and cough, with crab processing (Pjobs as male or female. Allergen sampling (211 allergen samples: 115 area, 96 personal breathing zone) indicated that the plant areas where these male jobs were concentrated were associated with lower levels of aerosolized crab allergens (the agents responsible for OA to snow crab) than areas associated with female jobs. This difference was statistically significant in the two plants with poor ventilation (pgender analysis of work history data showed that female health assessment participants were likely to have worked longer processing snow crab than males (5 years versus 3.5 years, respectively). Cross-referencing of work history results with allergen sampling data for male and female job areas showed a gender difference in median cumulative exposures (duration of exposure x level of exposures) for health assessment participants. Health assessment participants with estimated higher median cumulative exposures were more likely to receive a diagnosis of almost certain/highly probable OA and allergy. Semistructured interviews with 27 health assessment participants (24

  15. Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Payagalage Subashini Uddi De Silva, Jean Delayen

    2012-07-01

    The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication.

  16. Biometry, histology, and morphometry of the digestive system of wild crab-eating fox (Cerdocyon thous)

    OpenAIRE

    Andreíza Ramos Heleno; Luiz Michel Santos; Maria Angélica Miglino; Jayme Augusto Peres; Ricardo Romão Guerra

    2011-01-01

    The crab-eating fox (Cerdocyon thous) is found throughout Brazil. It has a nocturnal habit and can be seen on roadsides, where it looks for remains of run over animals and, therefore, it is also a victim of roadkill. This study aimed to characterize the macro and microscopic anatomy of the digestive system of the crab-eating fox. It helps to carry out medical and surgical procedures, besides important information on the feeding strategies, especially for wild individuals needing veterinary ca...

  17. The bioeconomic impact of different management regulations on the Chesapeake Bay blue crab fishery

    Science.gov (United States)

    Bunnell, David B.; Lipton, Douglas W.; Miller, Thomas J.

    2010-01-01

    The harvest of blue crabs Callinectes sapidus in Chesapeake Bay declined 46% between 1993 and 2001 and remained low through 2008. Because the total market value of this fishery has declined by an average of US $ 3.3 million per year since 1993, the commercial fishery has been challenged to maintain profitability. We developed a bioeconomic simulation model of the Chesapeake Bay blue crab fishery to aid managers in determining which regulations will maximize revenues while ensuring a sustainable harvest. We compared 15 different management scenarios, including those implemented by Maryland and Virginia between 2007 and 2009, that sought to reduce female crab harvest and nine others that used seasonal closures, different size regulations, or the elimination of fishing for specific market categories. Six scenarios produced the highest revenues: the 2008 and 2009 Maryland regulations, spring and fall closures for female blue crabs, and 152- and 165-mm maximum size limits for females. Our most important finding was that for each state the 2008 and 2009 scenarios that implemented early closures of the female crab fishery produced higher revenues than the 2007 scenario, in which no early female closures were implemented. We conclude that the use of maximum size limits for female crabs would not be feasible despite their potentially high revenue, given the likelihood that the soft-shell and peeler fisheries cannot be expanded beyond their current capacity and the potentially high mortality rate for culled individuals that are the incorrect size. Our model results support the current use of seasonal closures for females, which permit relatively high exploitation of males and soft-shell and peeler blue crabs (which have high prices) while keeping the female crab harvest sustainable. Further, our bioeconomic model allows for the inclusion of an economic viewpoint along with biological data when target reference points are set by managers.

  18. The 1997 event in the Crab Pulsar in X-rays

    Science.gov (United States)

    Vivekanand, M.

    2016-02-01

    Context. In October 1997, radio pulses from the Crab Pulsar underwent abnormal delay. This was reported by two radio observatories, both of which explained this frequency dependent and time varying delay as being due to refractive effects of ionized shells in the Crab Nebula. Both groups also noted that, curiously and confusingly coincident with the frequency dependent delay, the Crab Pulsar also underwent an unusual slowing down, which they believed to be unrelated to the Crab Nebula and instead intrinsic to the Crab Pulsar, resulting in an additional delay that was frequency independent. However, it now appears that one of the groups attributes the frequency independent delay also to refractive effects. Aims: This work aims to verify whether at least a part of the frequency independent delay is indeed due to intrinsic slowing down of the Crab Pulsar. Methods: Timing analysis of the Crab Pulsar's October 1997 event has been done in X-rays, which are not delayed by the refractive and diffractive effects that affect radio waves; at X-rays only the intrinsic slowing down should contribute to any observed delay. Data mainly from the PCA instrument aboard the RXTE satellite have been used, along with a small amount of data from the PDS instrument aboard the BeppoSAX satellite. Results: Analysis of the X-ray data, using the very accurate reference timing model derived at radio frequencies, strongly supports the intrinsic slowing down hypothesis. Analysis using the reference timing model derived self-consistently from the limited X-ray data, which is less accurate, is not completely unambiguous regarding the above two hypotheses, but provides reasonable support for the intrinsic slowing down hypothesis. Conclusions: A significant fraction of the frequency independent delay during the October 1997 event is indeed due to intrinsic slowing down of the Crab Pulsar.

  19. Acute exposure to high environmental ammonia (HEA) triggers the emersion response in the green shore crab.

    Science.gov (United States)

    Zimmer, Alex M; Wood, Chris M

    2017-02-01

    The physiological effects of high environmental ammonia (HEA) exposure have been well documented in many aquatic species. In particular, it has recently been demonstrated that exposure to ammonia in fish leads to a similar hyperventilatory response as observed during exposure to hypoxia. In littoral crabs, such as the green crab (Carcinus maenas), exposure to severe hypoxia triggers an emersion response whereby crabs escape hypoxia to breathe air. We hypothesized that exposure to HEA in green crabs would lead to a similar behavioural response which is specific to ammonia. Using an experimental arena containing a rock bed onto which crabs could emerse, we established that exposure to HEA (4mmol/l NH4HCO3) for 15min triggers emersion in crabs. In experiments utilizing NaHCO3 controls and NH4HCO3 injections, we further determined that emersion was triggered specifically by external ammonia and was independent of secondary acid-base or respiratory disturbances caused by HEA. We then hypothesized that emersion from HEA provides a physiological benefit, similar to emersion from hypoxia. Exposure to 15min of HEA without emersion (no rock bed present) caused significant increases in arterial haemolymph total ammonia (Tamm), pH, and [HCO3(-)]. When emersion was allowed, arterial haemolymph Tamm and [HCO3(-)] increased, but no alkalosis developed. Moreover, emersion decreased haemolymph partial pressure of NH3 relative to crabs which could not emerse. Overall, we demonstrate a novel behavioural response to HEA exposure in crabs which we propose may share similar mechanistic pathways with the emersion response triggered by hypoxia.

  20. Molecular detection of the parasitic dinoflagellate Hematodinium perezi from blue crabs Callinectes sapidus in Louisiana, USA.

    Science.gov (United States)

    Sullivan, Timothy J; Gelpi, Carey G; Neigel, Joseph E

    2016-06-15

    The dinoflagellate Hematodinium perezi is a prolific pathogen of the blue crab Callinectes sapidus along the Atlantic and Gulf of Mexico coasts of North America. High prevalence, sometimes approaching 100%, and outbreaks with high mortality are associated with higher salinities. H. perezi has not been reported previously in blue crabs from Louisiana, USA, where salinities in coastal habitats are generally below the parasite's favorable range. However, the possibility that H. perezi infects blue crabs in higher salinity habitats offshore has not been investigated. A PCR-based test for H. perezi was used to screen blue crabs collected from both high and low salinity areas. These included juvenile and adult crabs from inshore marshes where salinities are relatively low and from higher salinity offshore shoals that are spawning sites for females. H. perezi was detected in blue crabs from offshore shoals (prevalence=5.6%) but not in juvenile or adult crabs from inshore habitats. Megalopae (post-larvae) were also collected from inshore locations. Although megalopae settle inshore where salinities are relatively low, the megalopal stage is preceded by a planktonic phase in higher salinity offshore waters. We detected H. perezi in 11.2% of settling megalopae tested. Although the prevalence of H. perezi was relatively low within our samples, if spawning females and megalopae are especially vulnerable, the impact on the population could be compounded. This is the first report of H. perezi from blue crabs in Louisiana and demonstrates the importance of examining all life stages in determining the prevalence of a harmful parasite.