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Sample records for chinese mitten crab

  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. Distribution, Ecology and Potential Impacts of the Chinese Mitten Crab (Eriocheir sinensis) in San Francisco Bay

    OpenAIRE

    Rudnick, Deborah A; Halat, Kathleen M; Resh, Vincent H.

    2000-01-01

    The arrival of the Chinese mitten crab to the San Francisco Bay-San Joaquin Delta (Bay- Delta) ecosystem has been a source of widespread concern. This crab has spread from its native range, in China, to coastal ecosystems throughout Europe and, most recently, into North America. The Chinese mitten crab population in California has exploded within the last decade to cover hundreds of miles of the Bay-Delta and its tributaries. The Chinese mitten crab is a large, catadromous crab, moving from f...

  3. 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

  4. An Experimental Study on the Gait Patterns and Kinematics of Chinese Mitten Crabs

    Institute of Scientific and Technical Information of China (English)

    Jianqiao Li; Xiaodong Zhang; Meng Zou; Rui Zhang; Benard Chirende; Ruiyang Shi; Cangang Wei

    2013-01-01

    Despite the many studies on eight-legged animals and the importance of their mechanics of terrestrial locomotion,the mechanical energy of crabs in voluntary locomotion on uneven,unpredictable terrain surfaces has received little attention thus far.In this paper,motion video images of Chinese mitten crab (Eriocheir sinensis Milne-Edwards) locomotion on five types of terrains were recorded using a high-speed three-dimensional (3D) recording video system.The typical variables of locomotion such as gait patterns,duty factor,mechanical energy of the mass center,mass-specific rate of the total mechanical power of the mass center,and percentage recovery,were analyzed.Results show that the Chinese mitten crab uses random gaits instead of the alternating tetrapod gait with the increasing terrain roughness.The duty factors of the rows of the leading legs are greater for all terrains than those of the rows of the trailing legs.On smooth terrain,the duty factors of the rows of the trailing legs are greater than that on rough terrains.Kinematic measurements and calculations reveal that similar to mammals,birds,and arthropods,the Chinese mitten crab uses two fundamental gaits to save mechanical energy:the inverted pendulum gait and the bouncing gait.The bouncing gait is the main pattern of mechanical energy conservation.The low probability of injury and energy expenditure due to adaptations to various terrains induce the Chinese mitten crab to modify the mass-specific rate of the total mechanical power of the mass center.The statistical results of percentage recovery also reveal that the Chinese mitten crab has lower energy recovery efficiency over rough terrains compared with smooth terrains.

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

    NARCIS (Netherlands)

    Hoogenboom, L.A.P.; Kotterman, M.J.J.; Hoek - van Nieuwenhuizen, M.; Lee, van der M.K.; Mennes, W.C.; Jeurissen, S.M.F.; Leeuwen, van S.P.J.

    2015-01-01

    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

  6. 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.

  7. 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.

  8. Molecular cloning and gene expression analysis of the leptin receptor in the Chinese mitten crab Eriocheir sinensis.

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    Hui Jiang

    Full Text Available BACKGROUND: Leptin is an adipocyte-derived hormone with multiple functions that regulates energy homeostasis and reproductive functions. Increased knowledge of leptin receptor function will enhance our understanding of the physiological roles of leptin in animals. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, a full-length leptin receptor (lepr cDNA, consisting of 1,353 nucleotides, was cloned from Chinese mitten crab (Eriocheir sinensis using rapid amplification of cDNA ends (RACE following the identification of a single expressed sequence tag (EST clone in a cDNA library. The lepr cDNA consisted of a 22-nucleotide 5'-untranslated region (5' UTR, a 402-nucleotide open reading frame (ORF and a 929-nucleotide 3' UTR. Multiple sequence alignments revealed that Chinese mitten crab lepr shared a conserved vacuolar protein sorting 55 (Vps55 domain with other species. Chinese mitten crab lepr expression was determined in various tissues and at three different reproductive stages using quantitative real-time RT-PCR. Lepr expression was highest in the intestine, thoracic ganglia, gonad, and accessory gonad, moderate in hepatopancreas and cranial ganglia, and low in muscle, gill, heart, haemocytes, and stomach. Furthermore, lepr expression was significantly higher in the intestine, gonad and thoracic ganglia in immature crabs relative to precocious and mature crabs. In contrast, lepr expression was significantly lower in the hepatopancreas of immature crabs relative to mature crabs. CONCLUSIONS/SIGNIFICANCE: We are the first to identify the lepr gene and to determine its gene expression patterns in various tissues and at three different reproductive stages in Chinese mitten crab. Taken together, our results suggest that lepr may be involved in the nutritional regulation of metabolism and reproduction in Chinese mitten crabs.

  9. 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.

  10. Transcriptome profiling of the eyestalk of precocious juvenile Chinese mitten crab reveals putative neuropeptides and differentially expressed genes.

    Science.gov (United States)

    Xu, Zhiqiang; Zhao, Muzi; Li, Xuguang; Lu, Quanping; Li, Yuehua; Ge, Jiachun; Pan, Jianlin

    2015-09-15

    Chinese mitten crabs that reach maturity 1 year earlier than normal crabs are known as precocious juvenile crabs. The molecular mechanisms underlying the precocity of the Chinese mitten crab are poorly understood. To identify the genes that may be involved in the control of precocity in Chinese mitten crab, we measured the expression profile of eyestalk genes in precocious and normally developed juvenile crabs using high-throughput sequencing on an Illumina HiSeq 2500 platform. We obtained 56,446,284 raw reads from the precocious crabs and 58,029,476 raw reads from the normally developed juvenile crabs. Reads from the two libraries were combined into a single data set. De novo assembly of the combined read set yielded 78,777 unigenes with an average length of 1563 bp. A total of 41,405 unigenes with predicted ORFs were selected for functional annotation. Among these genes, we identified three neuropeptide genes belonging to the crustacean hyperglycemic hormone family and two neuropeptide genes encoding the chromatophorotropic hormones. Transcriptome comparison between the two libraries revealed 42 genes that exhibited significant differential expression, of which 29 genes were up-regulated and 13 genes were down-regulated in the precocious crabs. To confirm the sequencing data, six differentially expressed genes with functional annotations were selected and validated by qRT-PCR. In conclusion, we obtained the comprehensive transcriptome of the eyestalk tissues of precocious juvenile crabs. The sequencing results may provide new insights into the biomolecular basis of precocity in the Chinese mitten crab.

  11. GENETIC ANALYSIS OF THE CHINESE MITTEN CRAB (ERIOCHEIR SINENSIS) INTRODUCED TO THE NORTH AMERICAN GREAT LAKES AND ST. LAWRENCE SEAWAY

    Science.gov (United States)

    The Chinese mitten crab (Eriocheir sinensis) is a globally invasive organism, with established non-native populations in Europe and California, USA. Since 1965, there have been sixteen confirmed catches of E. sinensis in the North American Great Lakes and their associated waterw...

  12. Sustainable fisheries in shallow lakes: an independent empirical test of the Chinese mitten crab yield model

    Science.gov (United States)

    Wang, Haijun; Liang, Xiaomin; Wang, Hongzhu

    2016-08-01

    Next to excessive nutrient loading, intensive aquaculture is one of the major anthropogenic impacts threatening lake ecosystems. In China, particularly in the shallow lakes of mid-lower Changjiang (Yangtze) River, continuous overstocking of the Chinese mitten crab (Eriocheir sinensis) could deteriorate water quality and exhaust natural resources. A series of crab yield models and a general optimum-stocking rate model have been established, which seek to benefit both crab culture and the environment. In this research, independent investigations were carried out to evaluate the crab yield models and modify the optimum-stocking model. Low percentage errors (average 47%, median 36%) between observed and calculated crab yields were obtained. Specific values were defined for adult crab body mass (135 g/ind.) and recapture rate (18% and 30% in lakes with submerged macrophyte biomass above and below 1 000 g/m2) to modify the optimum-stocking model. Analysis based on the modified optimum-stocking model indicated that the actual stocking rates in most lakes were much higher than the calculated optimum-stocking rates. This implies that, for most lakes, the current stocking rates should be greatly reduced to maintain healthy lake ecosystems.

  13. Mercury burdens in Chinese mitten crabs (Eriocheir sinensis) in three tributaries of southern San Francisco Bay, California, USA

    International Nuclear Information System (INIS)

    Chinese mitten crabs (Eriocheir sinensis), endemic to Asia, were first reported in the San Francisco Bay in 1992. They are now established in nearly all San Francisco Bay tributaries. These crabs accumulate more metals, such as mercury, than crustaceans living in the water column. Because their predators include fish, birds, mammals and humans, their mercury burdens have an exceptional potential to impact the ecosystem and public health. We sought to elucidate the potential threat of mitten crab mercury burdens in three adjacent streams in southern San Francisco Bay, one of which is known to be contaminated with mercury. Mitten crabs had hepatopancreas concentrations of total mercury and methylmercury that did not differ among streams. The maximum burden we measured was below the action level of 1 ppm recommended by the USEPA. Hepatopancreas concentrations of methylmercury declined with increasing crab size, suggesting a mechanism for mercury excretion and that predators might reduce mercury exposure if they select larger crabs. Because mercury may be heterogeneously distributed among tissues, estimation of the impacts of crab mercury burdens on the environment requires more data on the feeding preferences of predators. - Hepatopancreas concentrations of mercury decline with crab size, which may have important consequences for bio-magnification in food webs

  14. Mercury burdens in Chinese mitten crabs (Eriocheir sinensis) in three tributaries of southern San Francisco Bay, California, USA

    Science.gov (United States)

    Hui, C.A.; Rudnick, D.; Williams, E.

    2005-01-01

    Chinese mitten crabs (Eriocheir sinensis), endemic to Asia, were first reported in the San Francisco Bay in 1992. They are now established in nearly all San Francisco Bay tributaries. These crabs accumulate more metals, such as mercury, than crustaceans living in the water column. Because their predators include fish, birds, mammals and humans, their mercury burdens have an exceptional potential to impact the ecosystem and public health. We sought to elucidate the potential threat of mitten crab mercury burdens in three adjacent streams in southern San Francisco Bay, one of which is known to be contaminated with mercury. Mitten crabs had hepatopancreas concentrations of total mercury and methylmercury that did not differ among streams. The maximum burden we measured was below the action level of 1 ppm recommended by the USEPA. Hepatopancreas concentrations of methylmercury declined with increasing crab size, suggesting a mechanism for mercury excretion and that predators might reduce mercury exposure if they select larger crabs. Because mercury may be heterogeneously distributed among tissues, estimation of the impacts of crab mercury burdens on the environment requires more data on the feeding preferences of predators. Hepatopancreas concentrations of mercury decline with crab size, which may have important consequences for bio-magnification in food webs. ?? 2004 Elsevier Ltd. All rights reserved.

  15. The characterization of hematopoietic tissue in adult Chinese mitten crab Eriocheir sinensis.

    Science.gov (United States)

    Jia, Zhihao; Kavungal, Sharath; Jiang, Shuai; Zhao, Depeng; Sun, Mingzhe; Wang, Lingling; Song, Linsheng

    2016-07-01

    Invertebrates rely on the efficient innate immune mechanisms against invaders, in which the continuous production of hemocytes (hematopoiesis) is indispensable. In the present study, the hematopoietic tissue (HPT) from Chinese mitten crab Eriocheir sinensis was identified and characterized. It was a thin and non-transparent sheet located at the dorsolateral side of the stomach, which was composed of a series of ovoid lobules. Each lobule was surrounded by connective tissue containing a large amount of spherical cells with big nucleus. In HPT, the cells were full of mitochondria and granules, and DNA replication was detected in some cells by EdU labeling technique. Cell proliferation was observed in HPT by transmission electron microscope (TEM). The distribution of two transcription factors, GATA1 and RUNX1, were examined by human GATA1 and RUNX1 antibodies, respectively. Three homologues of RUNX1 were detected in the HPT while no signal of RUNX1 was observed in hemocytes, and GATA1 was detected in both HPT and some hemocytes. The mRNA transcript of a novel hematopoiesis related cytokine EsAst was detected in hepatopancreas and hemocytes, but it was no detectable in HPT. The mRNA expression level of EsAst in hepatopancreas was 1.38-fold higher than that in hemocytes. Total hemocytes counts were related to the mRNA expression level of EsAst post Aeromonas hydrophila challenge. The results suggested that the stem cells in the hematopoietic tissue of Chinese mitten crab E. sinensis were regulated by transcriptional and humoral factors to generate hemocytes. PMID:26868307

  16. The immunosuppressive effects of continuous CpG ODNs stimulation in chinese mitten crab, Eriocheir sinensis

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    D Zhao

    2016-02-01

    Full Text Available CpG oligodeoxynucleotides (CpG ODNs have been widely used as a novel vaccine adjuvant in mammals due to its immune protection, long effectiveness and safety. In the present study, the long-term immune effects as well as immunosuppression of CpG ODNs was evaluated by comparing the immune parameters of Chinese mitten crab, Eriocheir sinensis after continuous or interval feeding with CpG ODNs-supplement diet for 21 days (designated as CC and CI group, respectively. In the CI group, the mRNA transcripts of EsTolls (EsToll1 and EsToll2 and EsMyD88 (adaptor molecule in hepatopancreas maintained at a significantly higher level (p < 0.05 compared with the CC group after 7 days and 14 days feeding, while there was no significant difference between them at the 21st day. Moreover, after a significant increase at 7th day, the expression level of EsLITAF mRNA [Lipopolysaccharide-induced tumor necrosis factor (TNF-α] in CC group decreased at 14th-21st day, while that in CI group kept increasing at 14th day, followed by a decrease at 21st day. The TNF-α in plasma of CC group was abnormally increased at the 21st day (p < 0.05 in CC group compared with the significant raise at 7th-14th in CI group. Moreover, the phagocytic activity and reactive oxygens (ROS level of hemocytes in continuous CpG ODNs feeding crabs were significantly lower than those in interval feeding crabs. These results indicated that long-term and continuous CpG ODNs stimulation could reduce the activation of pro-inflammatory cytokine production, hemocyte phagocytosis and ROS generation, displaying immunosuppressive effects on the immune system of crabs.

  17. Identification and characterization of a Cystatin gene from Chinese mitten crab Eriocheir sinensis.

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    Li, Fengmei; Gai, Xuemei; Wang, Lingling; Song, Linsheng; Zhang, Huan; Qiu, Limei; Wang, Mengqiang; Siva, Vinu S

    2010-09-01

    Cystatins are a superfamily of proteins as reversible inhibitor of cysteine proteinases which play essential roles in a spectrum of physiological and immunological processes. In this study, a novel member of Cystatin superfamily was identified from Chinese mitten crab Eriocheir sinensis (designated EsCystatin) by expressed sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EsCystatin was of 1486 bp, consisting of a 5'-terminal untranslated region (UTR) of 92 bp, a 3' UTR of 1034 bp with a polyadenylation signal sequence AATAAA and a polyA tail, and an open reading frame (ORF) of 360 bp encoded a polypeptide of 120 amino acids with the theoretical isoelectric point of 5.48 and the predicted molecular weight of 13.39 kDa. A signal Cystatin-like domain (Gly(25) to Lys(112)) was found in the putative amino acid sequences of EsCystatin. Similar to other Cystatins, the conserved central Q(70)VVSG(74) motif was located in the Cystatin-like domain of EsCystatin. But EsCystatin lacked of signal peptide and disulphide bond. The EsCystatin exhibited homology with the other known Cystatins from invertebrates and higher vertebrates, and it was clustered into Cystatin family 1 in the phylogenetic tree. The mRNA transcripts of EsCystatin were mainly expressed in hemolymph, gill, hepatopancreas, gonad and muscle, and also marginally detectable in heart. After Listonella anguillarum challenge, the relative expression level of EsCystatin in hemolymph was down-regulated to 0.6-fold (P Cystatin family, was a potent inhibitor of papain and involved in immune response versus invading microorganisms.

  18. Dietary nano-selenium relieves hypoxia stress and, improves immunity and disease resistance in the Chinese mitten crab (Eriocheir sinensis).

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    Qin, Fenju; Shi, Miaomiao; Yuan, Hongxia; Yuan, Linxi; Lu, Wenhao; Zhang, Jie; Tong, Jian; Song, Xuehong

    2016-07-01

    Hypoxia is a relevant physiological challenge for crab culture, and the hemolymph plays a crucial role in response to the hypoxia. In a 60 d feeding trial, Chinese mitten crabs (Eriocheir sinensis) fed a diet containing 0.2 mg/kg nano-selenium (nanoSe) showed a significantly increased weight gain rate (WGR) and a reduced feed coefficient (FC) compared to those fed diets with 0, 0.1, 0.4, 0.8, and 1.6 mg/kg nanoSe. Another 90 d feeding trial was conducted to determine the influence of dietary nanoSe on the immune response in juvenile Chinese mitten crabs kept under the condition of hypoxia. The results showed that hypoxia stress resulted in significantly increased hemocyte counts (THC, LGC, SGC, and HC), expression levels of the hemocyanin gene and protein, lactic acid level, and antioxidant capacity (T-AOC activities, SOD activities, GSH-Px and GSH content) in hemolymph supernatant. When these crabs were infected with Aeromonas hydrophila bacteria, hypoxia exposure increased mortality, but it was alleviated by a diet supplemented with 0.2 mg/kg nanoSe. The up-regulative effects of nanoSe (0.2 mg/kg) on antioxidant capacity, hemocyte counts, and hemocyanin expression under hypoxia exposure were further strengthened throughout, whereas lactic acid levels induced by hypoxia stress were restored. Thus, the observations in this study indicate that the level of dietary nanoSe is important in regulating immunity and disease resistance in crabs kept under hypoxia stress. PMID:27153751

  19. Molecular characterization and expression profiles of four transformer-2 isoforms in the Chinese mitten crab Eriocheir sinensis

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    Luo, Danli; Liu, Yuan; Hui, Min; Song, Chengwen; Liu, Hourong; Cui, Zhaoxia

    2016-09-01

    The transformer-2 (tra-2) gene plays a key role in the regulatory hierarchy of sexual differentiation in somatic tissues and in the germline of Drosophila melanogaster. In this study, sequences and expression profiles of tra-2 in the Chinese mitten crab Eriocheir sinensis were characterized. Four tra-2 isoforms, designated as Estra-2a, Estra-2b, Estra-2c and Estra-2d, were isolated. They all contained an RNA-recognition motif (RRM) and a linker region, which shared high similarity with other reported tra-2s. Sequence analysis revealed that Estra-2a, Estra-2b and Estra-2c are encoded by the same genomic locus and are generated by alternative splicing of the pre-mRNA. Compared with the other three isoforms, Estra-2d lacks the RS2 domain. Quantitative real-time PCR showed that all four isoforms were highly expressed in the fertilized egg, and in the 2-4 cell and blastula stages compared with larval stages (P≤ 0.01), suggesting their maternal origin in early embryonic developmental stages. Notably, Estra-2a was highly expressed in male somatic tissues, while Estra-2c was significantly highly expressed in the ovary. These results suggest that Estra-2c is involved in sexual differentiation of the Chinese mitten crab. Our findings provide basic information for further functional studies of the tra-2 gene/protein in this species.

  20. Spatial variations of macrozoobenthos and sediment nutrients in Lake Yangcheng: Emphasis on effect of pen culture of Chinese mitten crab.

    Science.gov (United States)

    Chen, Liping; Zhang, Ying; Liu, Qigen; Hu, Zhongjun; Sun, Yuejuan; Peng, Ziran; Chen, Lijing

    2015-11-01

    We determined the effect of Chinese mitten crab (CMC) pen culture on the quantified spatial distribution of the macrozoobenthic community and sediment nutrients in Lake Yangcheng. Redundancy analysis indicated that water temperature, macrophyte occurrence, sediment type, and crab culture were the main environmental factors that influence the spatiotemporal macrozoobenthic distribution. Macrozoobenthic assemblages in the lake were characterized by eutrophic indicator species. In the most polluted estuaries, the abundance and diversity indices of the whole community and abundance of chironomids and oligochaetes were significantly depressed, and sediment carbon (C) and phosphorus (P) were significantly enhanced compared with those in the western, middle (MB), and eastern basin (EB). Crab culture in this lake had significant effects on the species composition of the macrozoobenthic community in one of three CMC culture pens (CP), and generally depressed the abundance of most chironomid and oligochaete species. Significantly increased diversity, evenness, sediment carbon and nitrogen content, and sediment C:P ratio in the CP were found compared with those in the three basins. However, no conspicuous difference in sediment P content between the CP and the two basins of MB and EB was detected. Our results showed that the enhanced diversity and evenness of macrozoobenthos might be associated with the joint effect of macrophyte planting and crab predation, and macrophyte planting may modify the effects of CMC culture by leading to disproportional accumulation of C and N in the sediment relative to P in the CP of the lake. PMID:26574095

  1. Water quality, nutrient budget, and pollutant loads in Chinese mitten crab (Eriocheir sinensis) farms around East Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    CAI Chunfang; GU Xiaohong; HUANG Hezhong; DAI Xiuying; YE Yuantu; SHI Chenjiang

    2012-01-01

    To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake,China,we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009.We estimated the nitrogen (N),phosphorus (P),and chemical oxygen demand (COD) loads.Materials input and output ponds,water exchange,and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires.Water quality of 12 ponds,which were located no more than 2 km from East Taihu Lake,were monitored.The results show that water quality in the crab ponds was better than reference data.Feeds,including corn seed,commercial feed,trash fish,and gastropod,were the major sources of N and P input in the crab ponds,contributing 88.7% and 94.9%,respectively.In total,60.5% of N and 37.3% of P were sequestered by macrophytes,and only 15.7% and 8.5% of them were discharged as effluent.The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle,respectively,while the COD load was -17.88 kg/hm2/cycle.This indicated that crab farming caused minor negative impact on the trophic status of the lake area,which was attenuated by macrophytes.However,wastewater purification is still necessary in crab faming.

  2. Mercury (Hg2+) effect on enzyme activities and hepatopancreas histostructures of juvenile Chinese mitten crab Eriocheir sinensis

    Science.gov (United States)

    Zhao, Yanmin; Wang, Xinhua; Qin, Yanwen; Zheng, Binghui

    2010-05-01

    We studied the effects of mercury (Hg2+) on antioxidant and digestive enzyme activities in terms of LC50 value and on hepatopancreas histostructures of juvenile Chinese mitten crabs Eriocheir sinensis in 40-day exposure to various concentrations of Hg2+ (0, 0.01, 0.05, 0.10, 0.20, and 0.30 mg/L). The results show that the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) significantly increased in the concentrations of 0.01 and 0.05 mg/L, while that of enzyme decreased in 0.10, 0.20 and 0.30 mg/L treatments. Meanwhile, Hg2+ disrupted the histostructures of the hepatopancreas, causing decreases in activities of pepsin, tryptase, amylase, and cellulose, which are synthesized in the hepatopancreas. Moreover, as the Hg2+ concentration increased, the survival rate of the crabs decreased, worst at 56.57% in 0.30 mg/L. Therefore, although crabs are able to tolerate low levels of mercury pollution, high levels lead to cellular injury and tissue damage in hepatopancreas, which then loses some of its vital physiological functions such as absorption, storage, and secretion.

  3. Fatty acid binding proteins FABP9 and FABP10 participate in antibacterial responses in Chinese mitten crab, Eriocheir sinensis.

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    Full Text Available Invertebrates rely solely on the innate immune system for defense against pathogens and other stimuli. Fatty acid binding proteins (FABP, members of the lipid binding proteins superfamily, play a crucial role in fatty acid transport and lipid metabolism and are also involved in gene expression induced by fatty acids. In the vertebrate immune system, FABP is involved in inflammation regulated by fatty acids through its interaction with peroxidase proliferator activate receptors (PPARs. However, the immune functions of FABP in invertebrates are not well characterized. For this reason, we investigated the immune functionality of two fatty acid binding proteins, Es-FABP9 and Es-FABP10, following lipopolysaccharide (LPS challenge in the Chinese mitten crab (Eriocheir sinensis. An obvious variation in the expression of Es-FABP9 and Es-FABP10 mRNA in E. sinensis was observed in hepatopancreas, gills, and hemocytes post-LPS challenge. Recombinant proteins rEs-FABP9 and rEs-FABP10 exhibited distinct bacterial binding activity and bacterial agglutination activity against Escherichia coli and Staphylococcus aureus. Furthermore, bacterial growth inhibition assays demonstrated that rEs-FABP9 responds positively to the growth inhibition of Vibrio parahaemolyticuss and S. aureus, while rEs-FABP10 responds positively to the growth inhibition of Aeromonas hydrophila and Bacillus subtilis. Coating of agarose beads with recombinant rEs-FABP9 and rEs-FABP10 dramatically enhanced encapsulation of the beads by crab hemocytes in vitro. In conclusion, the data presented here demonstrate the participation of these two lipid metabolism-related proteins in the innate immune system of E. sinensis.

  4. PRELIMINARY STUDY ON SPERM AS VECTOR FOR INTRODUCING FOREIGN DNA INTO CHINESE MITTEN CRAB (ERIOCHEIR SINENSIS)%以精子为载体把外源DNA导入中华绒螯蟹的初步研究

    Institute of Scientific and Technical Information of China (English)

    刘向宇; 王铁辉; 张菁; 邱涛; 陆仁后

    2002-01-01

    @@ The study of crustacean genetics and breeding has been received more and more attention due to the rapid development of the shrimp and crab aquaculture. Chromosome set manipulation on shrimp and crab[1][2],and the work on transgenic shrimp[3][4]have got some progress. However, there is no transgenic research reported on crab to our knowledge. The purpose of this paper is to study the feasibility of using sperm as vector to introduce foreign DNA into Chinese mitten crab (Eriocheir sinensis H.milne-Edwards), an economically important crab in China.

  5. 3-D Surveying and Gaits Analysis of Chinese Mitten Crab in Smooth Road%中华绒螯蟹平面运动三维观测和步态分析

    Institute of Scientific and Technical Information of China (English)

    李建桥; 张晓冬; 邹猛; 李豪; 王洋; 石睿杨

    2012-01-01

    为了研究中华绒螯蟹在平面行走的步态,使用高速摄像机和三维运动分析软件建立了运动图像采集和分析系统.结果表明:中华绒螯蟹在行走时采用交替四角步态;相邻的两腿之间异步,相隔和对角线两条腿之间同步;各腿的负荷因数为(55.60±7.53)%,说明中华绒螯蟹通过增加支撑相使其身体在行走时更加稳定.%In order to investigate the gait of Chinese mitten crab, a motion images recorded and analyzed systems was established with high speed camera and 3-D motion analysis software. The results showed that Chinese mitten crab performed alternating tetrapod gait when walking on smooth road. Adjacent ipsilateral and segmental pairs of legs alternated with each other; Subadjacent ipsilateral legs and diagonal pairs of legs moved together. Duty factor of each leg was ( 55. 60 ± 7. 53 ) % , which indicated that Chinese mitten crab made its body more stable during walking through increasing support phase.

  6. Cloning and Functional Analysis of Histones H3 and H4 in Nuclear Shaping during Spermatogenesis of the Chinese Mitten Crab, Eriocheir sinensis.

    Directory of Open Access Journals (Sweden)

    Jiang-Li Wu

    Full Text Available During spermatogenesis in most animals, the basic proteins associated with DNA are continuously changing and somatic-typed histones are partly replaced by sperm-specific histones, which are then successively replaced by transition proteins and protamines. With the replacement of sperm nuclear basic proteins, nuclei progressively undergo chromatin condensation. The Chinese Mitten Crab (Eriocheir sinensis is also known as the hairy crab or river crab (phylum Arthropoda, subphylum Crustacea, order Decapoda, and family Grapsidae. The spermatozoa of this species are aflagellate, and each has a spherical acrosome surrounded by a cup-shaped nucleus, peculiar to brachyurans. An interesting characteristic of the E. sinensis sperm nucleus is its lack of electron-dense chromatin. However, its formation is not clear. In this study, sequences encoding histones H3 and H4 were cloned by polymerase chain reaction amplification. Western blotting indicated that H3 and H4 existed in the sperm nuclei. Immunofluorescence and ultrastructural immunocytochemistry demonstrated that histones H3 and H4 were both present in the nuclei of spermatogonia, spermatocytes, spermatids and mature spermatozoa. The nuclear labeling density of histone H4 decreased in sperm nuclei, while histone H3 labeling was not changed significantly. Quantitative real-time PCR showed that the mRNA expression levels of histones H3 and H4 were higher at mitotic and meiotic stages than in later spermiogenesis. Our study demonstrates that the mature sperm nuclei of E. sinensis contain histones H3 and H4. This is the first report that the mature sperm nucleus of E. sinensis contains histones H3 and H4. This finding extends the study of sperm histones of E. sinensis and provides some basic data for exploring how decapod crustaceans form uncondensed sperm chromatin.

  7. Effects of 3 Feeding Modes on the Volatile and Nonvolatile Compounds in the Edible Tissues of Female Chinese Mitten Crab (Eriocheir sinensis).

    Science.gov (United States)

    Zhuang, Kejin; Wu, Na; Wang, Xichang; Wu, Xugan; Wang, Shuai; Long, Xiaowen; Wei, Xuan

    2016-04-01

    To reveal the impact of different feeding modes on the flavor quality of female Chinese mitten crab (Eriocheir sinensis) this study was conducted to compare the sensory evaluation scores, flavor compounds in meat and hepatopancreas of female E. sinensis fed with 3 feeding modes, that is, natural diets (NDs), traditional diets (TDs), and formulated diets (FDs). The result showed that crabs fed with ND had significantly lower sensory scores than the other 2 feeding modes in both edible tissues. The odor and taste profiles were evaluated by Electronic nose (E-nose) and tongue (E-tongue) techniques, respectively; results of perchloric acid showed each edible tissue had significant differences among the 3 modes. Contents of volatile compounds were measured by Headspace-solid phase micro extraction combined with gas chromatography-mass spectrometer. A total of 35 and 44 volatile compounds were identified in meat and hepatopancreas, respectively. ND mode of meat had the highest relative odor activity value (ROAV) summation among the 3 diet modes. TD mode of hepatopancreas had significantly higher ROAV summations. Based on the analysis of free amino acids and 5'-nucleotides, nonvolatile compounds were evaluated by equivalent umami concentration (EUC) and taste active values (TAVs) methods. For both meat and hepatopancreas, TD had the highest contents of umami amino acid, as for the 5'-nucleotide, FD had the highest 5'-inosin monophosphate concentrations. Overall, the EUC and TAVs of TD were higher than that of FD, whereas ND mode had the lowest values in the 2 edible tissues. In conclusion, TD mode had the best performance in terms of sensory evaluation, ROAVs of aroma-active compounds, and nonvolatile active compounds. PMID:26919186

  8. Molecular cloning and characterization of a cytoplasmic manganese superoxide dismutase and a mitochondrial manganese superoxide dismutase from Chinese mitten crab Eriocheir sinensis.

    Science.gov (United States)

    Wang, Mengqiang; Wang, Lingling; Yi, Qilin; Gai, Yunchao; Song, Linsheng

    2015-11-01

    Superoxide dismutase (SOD) functions as the first and essential enzyme in the antioxidant system and is ubiquitously existed in both prokaryotes and eukaryotes. In the present study, both cytoplasmic and mitochondrial manganese SOD were identified from Chinese mitten crab Eriocheir sinensis (designed as EscytMnSOD and EsmtMnSOD). The complete nucleotide sequence of EscytMnSOD comprised 1349 bp and consisted of a 5' untranslated regions (UTR) of 43 bp, a 3' UTR of 445 bp and an open reading frame (ORF) of 861 bp encoding a polypeptide of 286 amino acid residues. The full-length cDNA sequence of EsmtMnSOD comprised 990 bp, containing a 5' UTR of 55 bp, a 3' UTR of 278 bp and an ORF of 657 bp encoding a polypeptide of 218 amino acid residues. The deduced amino acid sequences of EscytMnSOD and EsmtMnSOD contained highly conserved MnSOD signature and typical functional domain, and exhibited high similarity with their reported homologues. In the phylogenetic tree, EscytMnSOD and EsmtMnSOD were clustered with their homologues from the land crab Cardisoma armatum. The EscytMnSOD and EsmtMnSOD transcripts were constitutively expressed in haemocytes, muscle, heart, gill, haepatopancreas and gonad, with the highest expression level in gills and haepatopancreas, respectively. The mRNA expression levels of them were all up-regulated in haemocytes with similar profiles after the stimulation of Vibrio anguillarum, Micrococcus luteus and Pichia pastoris. The EsmtMnSOD with low basal expression level responded to invading microbes intensely, while the EscytMnSOD with high basal expression level exhibited mild responses against stimulating microbes. The purified rEscytMnSOD and rEsmtMnSOD proteins exhibited specific Mn(2+)-dependent enzymatic activities, while rEscytMnSOD with lower basic activity displayed higher stability than rEsmtMnSOD. All these results indicated that EscytMnSOD and EsmtMnSOD were efficiently antioxidant enzymes and potentially involved in the innate immune

  9. A novel SoxB2 gene is required for maturation of sperm nucleus during spermiogenesis in the Chinese mitten crab, Eriocheir sinensis

    Science.gov (United States)

    Liu, Zhi-Qiang; Jiang, Xue-Hui; Qi, Hai-Yan; Xiong, Liang-Wei; Qiu, Gao-Feng

    2016-01-01

    SRY-related HMG box (Sox) genes are characterized by the presence of a DNA-binding HMG domain and involved in a diverse range of developmental processes. In this study, we identified a novel Sox gene, designated as EsSoxB2-1, from the Chinese mitten crab Eriocheir sinensis. The EsSoxB2-1 encodes a protein of 259 amino acids, sharing the highest identity with the beetle Tribolium castaneum SOX21b. Unlike insect Sox21b, however, EsSoxB2-1 is intronless and exhibits a gonad-specific expression pattern at both mRNA and protein level. Two core promoters in 5′ flanking region were demonstrated to be essential for inducing transcriptional regulatory activity. The transcription of EsSoxB2-1 mRNA begins in spermatogonia stage, while the translation of EsSOXB2-1 protein initiates at spermiogenesis stage. Interestingly, EsSOXB2-1 protein was exclusively localized in the nucleus of spermatid and spermatozoa even at the end of acrosome reaction, and was bound to the uncondensed chromatin in nucleoplasm of mature spermatozoa. Knockdown of EsSoxB2-1 by RNAi leads to abnormal transformation of the nucleus during spermiogenesis. Together, these findings demonstrated the requirement of EsSoxB2-1 for the spermatozoa nucleus maturation and also suggested that EsSoxB2-1 would be delivered into fertilized eggs along with chromatins as a paternal transcription factor for regulating early embryonic development. PMID:27561408

  10. 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.

  11. Microfabricated interdigitated Au electrode for voltammetric determination of lead and cadmium in Chinese mitten crab (Eriocheir sinensis).

    Science.gov (United States)

    Xu, Yiwei; Zhang, Wen; Shi, Jiyong; Zou, Xiaobo; Li, Zhihua; Zhu, Yaodi

    2016-06-15

    An in-situ plating bismuth modified interdigitated Au electrode (IAE) was developed for determination of Pb(2+) and Cd(2+) in crab. The IAE was fabricated and used as counter electrode and working electrode. Cyclic voltammetry (CV) was performed with the IAE for studying electrochemical performance, showing clear redox peaks. The key operational parameters were optimized, which were 600 μg L(-1) of Bi(3+) concentration, 0.1 mol L(-1) of acetate buffer (pH 4.5), -1.2V of deposition potential and 180 s of deposition time. Under optimized condition, the linear range of IAE was from 5 to 50 μg L(-1) for both metal ions, with detection limit (threefold signal-to-noise) of 0.74 μg L(-1) for Pb(2+) and 0.86 μg L(-1) for Cd(2+). Finally, the developed sensor was applied to detect Pb(2+) and Cd(2+) in crab extract solutions by standard addition method. The results were in good agreement with outcomes obtained by inductively coupled plasma mass spectrometry. PMID:26868565

  12. Effect of microencapsulated vaccine of Aeromonas hydrophila on immune factors of Chinese mitten crab%嗜水气单胞菌微胶囊疫苗对中华绒螯蟹免疫因子的影响

    Institute of Scientific and Technical Information of China (English)

    李义; 刘永贵; 王明; 孙汉; 郭明凯; 俞泉宇

    2011-01-01

    The research item was to study the effect of microcapsules vaccine of Aeromonas hydrophila on the immune system of Chinese mitten crab, which was fed with the basal diets by adding lyophilized powder of microcapsules vaccine of Aeromonas hydrophila (1.5× 1012 cfu/g) in the dosages of 0 (control), 1, 3, 6 g/kg for 7 days, respectively; Then the 3 experimental groups were fed with the control basal diets. The peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (ALP) and nitric oxide synthase (NOS) activities in serum, and the superoxide dismutase (SOD) and lysozyme (LSZ) activities in hepatopancreas were determined respectively at 0,1,2, and 3 weeks after feeding the test diets. The results indicated that the activity of POD, ACP, ALP and NOS in serum, SOD and LSZ in hepatopancreas of Chinese mitten crab, which was fed with microcapsules vaccine of Aeromonas hydrophila in a certain amount were significantly improved (P<0.05) and the immune-stimulating effect was optimal in the dosage of 6 g/kg.%为检测嗜水气单胞菌微胶囊疫苗对中华绒螯蟹免疫机能的影响,在基础饲料中分别添加0(对照)、1、3和6 g/kg的嗜水气单胞菌微胶囊疫苗冻干粉(菌含量为1.5×1012cfu/g),制成颗粒饲料后投喂中华绒螯蟹7 d;然后3个试验组改投对照组饲料.在停喂试验组饲料后第0、1、2和3周,测定中华绒螯蟹血清POD、ACP、ALP、NOS活性和肝胰腺中的SOD与LSZ活性.结果显示:一定剂量的嗜水气单胞菌微胶囊疫苗能显著增强中华绒螯蟹血清POD、ACP、ALP、NOS和肝胰腺中的SOD与LSZ活性(P<0.05);且以6 g/kg饲料的添加量的免疫刺激效果最佳.

  13. Study on genetic variation and adaptive evolution from the native and colonized populations of Chinese mitten crab%中华绒螯蟹国内外群体遗传变异与适应性进化分析

    Institute of Scientific and Technical Information of China (English)

    成起萱; 周陆; 王成辉

    2013-01-01

    中华绒螯蟹(Eriocheir sinensis)是我国极为重要的土著种类,现已移居到欧洲和北美等地.利用20对微卫星标记对中华绒螯蟹国内土著群体(长江和黄河)和国外移居群体(德国易北河、荷兰莱茵河、英国泰晤士河和美国旧金山湾)的遗传变异和多样性进行了分析.结果显示,中华绒螯蟹国内群体的遗传多样性(等位基因丰富度、多态信息含量和杂合度等)略高于国外移居群体;国内外群体间,以及国外不同群体间存在显著的遗传分化;贝叶斯遗传聚类分析显示国内土著群体、欧洲移居群体和美国移居群体分成明显的3个遗传聚类;主成分分析表明国外移居群体已产生了明显的遗传歧化;荷兰莱茵河群体检测到显著的遗传瓶颈效应.表明中华绒螯蟹在海外的入侵过程中已发生了较为明显的适应性进化.%Chinese mitten crab (Eriocheir sinensis) is a very importantly native species in China. However, this species had been introduced to Europe and North America and had posed great influences on invaded ecosystems because of their rapid expansion. In this study, genetic variation and diversity of the Chinese mitten crab from its native ranges ( Yangtze and Yellow Rivers in China) and colonized regions (Elbe River in Germany, Rhine River in Netherlands, Thames River in UK and San Francisco Bay in USA) were investigated using twenty microsatellites loci. The results found that the native populations possess higher genetic diversity than the colonized populations, and significant genetic differentiation between the native and colonized populations, and among the colonized populations. Bayesian clustering analysis showed significant genetic cluster of the colonized population from the native populations, and also significant genetic variation between the North American and European populations. Principal component analysis (PCA) indicated the high level of genetic differentiation

  14. 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.

  15. 中华绒螯蟹性腺香气品质评价方法%Evaluation of aroma-quality Chinese mitten-handed crab (Eriocheir sinensis) gonad

    Institute of Scientific and Technical Information of China (English)

    顾赛麒; 王锡昌; 陶宁萍; 张晶晶; 吴娜

    2013-01-01

    HS-SPME-GC-MS technology was applied to identify the aroma compounds from the gonad of special, first and second grades of both male and female Chinese mitten-handed crabs cultured in Yangcheng Lake. Fifty-eight volatiles, which can be divided into eight classes, were identified from six kinds of crab samples and further quantitated based on internal standard analysis. The concentrations of eight classes of volatiles were stan-dardized first and then principal component analysis (PCA) analyzed the standard data. Comprehensive scores (also called S-scores), which were calculated from each principal component value and its variance contribution, were used to evaluate the aroma-quality of gonad. The results showed that special and first grades of female crabs had the highest aroma-quality among the six crab samples. Meanwhile, furans, ketones, aromatics, and aldehydes were identified as the four characteristic aroma species that related and contributed a lot to “better quality of aroma”. With a unified consideration of gender factor, we conclude that higher grades of crabs result in better quality of aroma. However, female crabs always acquired higher S-scores than males of the same grade. We have demonstrated that PCA can be used to successfully establish a model for evaluating aroma-quality of crab gonad. Our work offers some theoretical references for future efforts in flavor property improvement.%  采用顶空固相微萃取-气-质联用技术(HS-SPME-GC-MS),对采自阳澄湖的特级、1级、2级的雄性及雌性中华绒螯蟹(Eriocheir sinensis)性腺中的香气成分进行了鉴定并以内标法对其定量.6种中华绒螯蟹样本中共检测到8类58种挥发物,采用主成分分析法(PCA)对标准化后的8类香气成分的浓度值进行分析,以主成分综合得分作为评价依据得到:特级和1级雌蟹性腺的香气品质最好,且呋喃类、醇类、芳香类、醛类4类成分对其贡献显著,是表征“高

  16. 果胶和木聚糖对中华绒螯蟹生长性能和消化生理的影响%Effects of Pectin and Xylan on Growth Performance and Digestive Physiology of Chinese Mitten Crab ( Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    吴韬; 张振龙; 蔡春芳; 叶元土; 李婷; 朱健明

    2015-01-01

    To reveal the potential anti-nutritional effects of non-starch polysaccharides ( NSPs) in plant feed in-gredients, the effects of pectin and xylan on growth performance and digestive physiology of Chinese mitten crab ( Eriocheir sinensis) were studied. The pectin, enzymatic hydrolysis pectin, wheat bran ( xylan source) and enzymatic hydrolysis wheat bran were supplied into the experimental diets at 8%, 8%, 30% and 30%, re-spectively. Chinese mitten crab with an initial body weight of (5.9±0.4) g were over-fed experimental diets for eight weeks. Each experimental diet had 3 replicates with 50 crabs. Chinese mitten crab with an initial body weight of (42.0±2.1) g were used to digestion rate experiments. Each experimental diet had 3 replicates with 15 crabs. The results showed that no significant difference in growth performance of Chinese mitten crab was detected among groups ( P>0. 05 ) . The contents of serum cholesterol ( CHO ) , high density lipoprotein ( HDL) and low density lipoprotein ( LDL) of crabs fed the diet containing pectin were significantly lower than that of crabs fed the diets containing enzymatic hydrolysis pectin, xylan and enzymatic hydrolysis xylan ( P0.05) . Hepatopancreas trypsin activity of crabs fed the diet containing pectin was significantly lower than that of crabs fed the diet con-taining enzymatic hydrolysis pectin ( P0.05) , but both of them were significantly higher than of crabs fed the diet containing enzymatic hydrolysis pectin ( P0.05). 果胶组血清胆固醇( CHO)、高密度脂蛋白( HDL)和低密度脂蛋白( LDL)含量显著低于酶解果胶组、木聚糖组和酶解木聚糖组(P0.05). 果胶组肝胰腺胰蛋白酶活性显著低于酶解果胶组( P0.05) ,但均显著高于酶解果胶组(P<0.05). 木聚糖组肝胰腺淀粉酶活性显著低于酶解木聚糖组(P<0.05). 中华绒螯蟹对饲料中干物质、蛋白质和脂肪的表观消化率均呈现果胶组<酶解果胶组<木聚糖组<酶解木聚糖组的

  17. 三种常用农药对中华绒螯蟹幼蟹的急性毒性研究%Acute Toxicity of Three Pesticides to Juvenile Chinese Mitten Crab(Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    李赫; 宋文华; 李文宽; 富丽静; 姚福向; 胡宗云; 张涛; 张健

    2013-01-01

    The acute toxicity of avermectin, chlorpyrifos and triazophos to juvenile Chinese mitten crab(Eriocheir sinensis) with body weight (6.3±0.9)g was studied at water temperature of 20~23℃and pH 7.5 by a semi-static test method. The results showed that the median-lethal concentration of avermectin was found to be 126.02mg·L-1 for 24h, 95.82 mg·L-1 for 48h, 82.74 mg·L-1 for 72h and 73.44mg·L-1 for 96h. The median-lethal concentration of chlorpyrifos was shown to be 0.73 mg·L-1 for 24h, 0.65 mg·L-1 for 48h, 0.56mg·L-1 for 72h and 0.49 mg·L-1 for 96h. The median-lethal concentration of triazophos was 5.56 mg·L-1 for 24h, 4.49 mg·L-1 for 48h, 3.88mg·L-1 for 72h and 3.62mg·L-1 for 96h. The acute toxicity order of the three pesticides to Chinese mitten crab juveniles was ranged as chlorpyrifos>triazophos>avermectin.%在水温20~23℃、pH7.5条件下,采用半静态法研究了阿维菌素、毒死蜱和三唑磷对体质量(6.3±0.9)g中华绒螯蟹(Eriocheir sinensis)幼蟹的急性毒性。结果表明:阿维菌素对幼蟹24、48、72、96h的半致死质量浓度分别为126.02、95.82、82.74、73.44mg·L-1;毒死蜱对幼蟹24、48、72、96h的半致死质量浓度分别为0.73、0.65、0.56、0.49mg·L-1;三唑磷对幼蟹24、48、72、96h半致死质量浓度分别为5.56、4.49、3.88、3.62mg·L-1。三种药物对中华绒螯蟹幼蟹的毒性大小依次为:毒死蜱>三唑磷>阿维菌素。

  18. Dietary choline requirements of juvenile Chinese mitten crab, Eri-ocheir sinensis at two dietary phospholipid levels%不同磷脂水平下中华绒螯蟹幼蟹的胆碱需要量

    Institute of Scientific and Technical Information of China (English)

    齐霁; 陈立侨; 孙盛明; 姜海波; 李二超; 禹娜

    2013-01-01

    A 42-day feeding trial was conducted to investigate the effects of dietary phospholipids on the choline requirement of the juvenile Chinese mitten crab, Eriocheir sinensis. Twelve purified diets were formulated con-taining two phospholipid levels (1% and 2%) and six choline chloride levels (0, 250, 500, 1 000, 2 000 and 4 000 mg/kg diet), and were fed to E. sinensis juveniles (0.22g±0.01g) with four replicates in each treatment. The results showed that dietary choline and phospholipids had a significant interaction on survival, weight gain, specific growth rate and feed conversion ratio (P0.05);各试验组的全蟹粗脂肪含量、肝胰腺的甘油三酯含量、总胆固醇含量、谷草转氨酶和谷丙转氨酶活性,均随着饲料中胆碱量的增加而显著下降(P<0.05).综上所述,中华绒螯蟹幼蟹饲料中磷脂和胆碱存在显著的交互作用,饲料中适量添加胆碱和磷脂,可以显著提高幼蟹的增重率和特定生长率,降低饲料系数以及蟹体脂肪含量.以增重率为判据,采用折线回归法进行分析,得出饲料中不同磷脂水平下幼蟹的胆碱适宜需要量分别为1429.65 mg/kg 饲料(磷脂水平1%时)和529.65 mg/kg 饲料(磷脂水平2%).

  19. Isolation of the sex-associated fragments in the Chinese mitten crab(Eriocheir sinensis) using AFLP technique%利用AFLP方法筛选中华绒螯蟹性别相关标记

    Institute of Scientific and Technical Information of China (English)

    吕慧锋; 江学慧; 邱高峰

    2012-01-01

    利用AFLP(amplified fragment length polymorphism)技术筛选中华绒螯蟹性别相关标记,共使用192对引物组合检测中华绒螯蟹雌、雄和雌雄混合3个基因组池的多态性,共扩增出5 376条多态性条带,平均每对引物组合扩增出28条多态性条带,获得88条雌雄差异条带。利用雌雄各10个个体再次进行AFLP验证,共62条差异条带具有性别差异,包括两种情况:(1)有49条条带在雌性的4~6个个体中存在,在雄性全部个体中缺失;(2)有13条条带在雄性4~6个个体中存在,在所有的雌性个体中缺失;其余的26条没有性别差异性。差异条带经回收、克隆、测序,结果发现有些条带包含多个序列,共得到77条DNA序列,其中31条序列与鸟类、两栖类和哺乳类等脊椎动物性染色体DNA部分片段具有同源性,相似区间在22~212 bp不等,其中6条DNA序列与命中序列之间具有生物学相关性。设计特异性的引物在基因组中检测,没有获得性别特异SCAR标记。%In the present study,amplified fragment length polymorphism(AFLP) was used for the isolation of sex-associated markers in the genome of Chinese mitten crab,Eriocheir sinensis.By screening the male,female and male/female mix bulks with 192 selective AFLP primer combinations,we obtained 5 376 polymorphic fragments in total,each combination generated 28 fragments on average.A total of 88 sex difference AFLP candidates were retrieved.Subsequently,the candidates were further verified in 10 female and 10 male individuals by AFLP again.Sixty-two sex difference fragments were obtained finally,and they could be classified into two groups:(1) Thirteen bands were present in four to six male crabs and absent in all female crabs;(2) Forty-nine bands were present in four to six female crabs,but absent in all male crabs.No sex difference was found in the other 26 bands.The sex difference fragments were recovered,cloned and sequenced.The results showed

  20. Changes in cell type composition in the hepatopancreas of Chinese mitten crab Eriocheir sinensis during the molting cycle%中华绒螯蟹蜕皮周期中肝胰腺细胞组成的变化

    Institute of Scientific and Technical Information of China (English)

    田志环; 康现江; 焦传珍

    2013-01-01

    We used 1-year-old juvenile Chinese mitten crab Eriocheir sinensis with the shell width at 15−40 mm, temporally reared them in the aquarium of 75 cm×50 cm×45 cm, 24 h aerating and natural light. We changed the water at 1/3 each day and used potato and small fish as the feed for the crab. One week later we began the ex-periment. According to the reference reported, we divided the period of molting cycle of the E. sinensis into 5 stages as stage C (intermolting) , stages D0, D1, and D3-4 (premolt), and stage A-B(postmolt). We evaluated the changes in the hepatopancreas cell type composition during the molting cycle using cellular and histological methods. R (resorptive) cells were the most abundant cell type throughout the molting cycle, except during the postmolt A-B stage. The number of B (blisterlike) cells increased significantly (P0.05), but did increase significantly during the premolt D1 and D0 stages (P0.05) by fasting. During the D1 stage, fasting had no effect (P>0.05) on the numbers of all cell types. Our results suggest that hepatopancreas cell type composition of E. sinensis changes with molt stage. The purpose of this study is to un-derstand the basic biologic change during the molt of crustacean and to provide a fundamental reference for the healthy aquaculture of this species.%取一年生未成熟中华绒螯蟹(Eriocheir sinensis)幼蟹,甲壳宽度在15∼40 mm,暂养在75 cm×50 cm×45 cm的玻璃缸内,24 h充气,自然光照,每天换水1/3,每次换水后投喂土豆、杂鱼等食物,动物适应实验室条件1周后进行实验。为得到蜕皮后的样本,将处于蜕皮前晚期的个体在相同条件下单独饲养。根据已报道方法,将中华绒螯蟹的蜕皮周期分为蜕皮间期C期、蜕皮前D0、D1和D3-4期、蜕皮后A-B期等5个时期。采用细胞学和组织学方法观察中华绒螯蟹蜕皮过程中肝胰腺细胞组成的变化,结果显示,R 细胞数量在蜕皮间期和蜕皮前期都占绝对

  1. A comparative study of morphological characteristics and elemental fingerprints of Chinese mitten crab Eriocheir sinensis from three lakes%长江水系3个湖泊中华绒蟹形态及元素“指纹”特征

    Institute of Scientific and Technical Information of China (English)

    杨文斌; 苏彦平; 刘洪波; 杨健; 徐跑

    2012-01-01

    以江苏省长江水系3个不同湖泊(太湖、石臼湖和固城湖)产中华绒螯蟹(Eriocheir sinensis)群体为研究对象,分别对其进行形态学和元素“指纹”特征的比较研究.基于16个组形态数据的框架测量及相应的逐步判别分析结果表明,虽然太湖、石臼湖和固城湖产中华绒螯蟹3群体之间在形态学上存在一定的差异,且判别准确率分别为70%、90%和80%,但其差异程度尚未达到能够有效区分3个群体的水平.统一使用中华绒螯蟹第三步足作为标准试样,应用电感耦合等离子质谱仪测定了其中21种元素的含量和分布特征,其中Cr、Co、As、Se、Cd、Pb、T1、Ag、Mo、Ni未检出.与形态判别结果不同的是,3湖泊产中华绒螯蟹第三步足元素含量和分布的总体差异极为显著,太湖、石臼湖和固城湖产中华绒螯蟹的判别准确率分别高达100%、80%和100%.这表明本研究所尝试的中华绒螯蟹第三步足元素“指纹”分析判别方法具有有效区别不同产地中华绒螯蟹的潜力.%Morphological characteristics and elemental fingerprints were compared in Chinese mitten crabs (Eri-ocheir sinensis) from three lakes (Taihu Lake, Shijiu Lake and Gucheng Lake) in Jiangsu Province. Truss network analysis using 16 length measurements suggested that crabs from the three lakes could not be reliably characterized based on morphological characteristics. The accuracy rates yielded by discriminant analysis were 70% for crabs from Taihu Lake, 90% for those from Shijiu Lake, and 80% for those from Gucheng Lake. An Agilent 7500ce ICP-MS was used to measure the concentrations of 21 chemical elements (Na, K, Ca, Fe, Mg, Sr, Ag, Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl and Zn) in the third pereiopod of the crabs from the three lakes. The concentrations of Cr, Co, As, Se, Cd, Pb, Tl, Ag, Mo, and Ni were below the detection limit. However, in contrast to the morphological analysis, the

  2. 3种类胡萝卜素源对中华绒螯蟹体色改善效果的比较研究%Comparation of the Improvement Effect on Body Colour of Chinese Mitten Crab Caused by Three Carotenoid Sources

    Institute of Scientific and Technical Information of China (English)

    龚志; 伊淑平; 孔丽; 蔡春芳; 叶元土; 沈建明

    2014-01-01

    本试验旨在比较不同类胡萝卜素源对中华绒螯蟹体色的改善效果,以期为其品质优化提供参考。配制4种试验饲料,分别为对照饲料及添加2.00%螺旋藻( Spirulina)、0.55%雨生红球藻( Haematococcus pluvialis)、15%苜蓿粉的饲料,饲料中类胡萝卜素含量依次为6.0、67.2、67.6、49.5 mg/kg。选用初重为(8.9±0.3)g的中华绒螯蟹240只,随机分入16只水族箱,每箱15只。每种饲料投喂4箱蟹,试验期为60 d。结果表明:饲养试验结束时,各组中华绒螯蟹的终末体重、存活率和特定生长率差异不显著( P>0.05)。螺旋藻、雨生红球藻、苜蓿粉组中华绒螯蟹的头胸甲和肝胰腺中类胡萝卜素和虾青素含量均依次升高,且均显著高于对照组( P<0.05)。此外,苜蓿粉组头胸甲和肝胰腺中类胡萝卜素和虾青素含量均显著高于螺旋藻组( P<0.05)。由此得出,螺旋藻、雨生红球藻、苜蓿粉均具有改善中华绒螯蟹体色的作用,且以苜蓿粉的效果最好。%This study was conducted to compare the improvement effect on body colour of Chinese mitten crab caused by three carotenoid sources,in order to provide a reference for optimizing quality of Chinese mitten crab. Four experimental diets were formulated,including a control diet and three diets in which adding 2.00%Spirulina,0.55% Haematococcus pluvialis and 15.00% alfalfa meal,respectively,and the content of carote-noid in those diets was 6.0,67.2,67.6 and 49.5 mg/kg,accordingly. Two hundred and forty Chinese mitten crabs with the initial body weight of(8.9±0.3)g were stored in 16 tanks with 15 crabs per tank. Each diet fed crabs in 4 tanks for 60 days. The results showed as follows:at the end of the feeding trial,no significant differ-ences were observed in final body weight,survival rate and specific growth rate among all groups( P>0.05). The contents of carotenoid and

  3. Transcriptome analysis and discovery of genes involved in immune pathways from hepatopancreas of microbial challenged mitten crab Eriocheir sinensis.

    Directory of Open Access Journals (Sweden)

    Xihong Li

    Full Text Available BACKGROUND: The Chinese mitten crab Eriocheir sinensis is an important economic crustacean and has been seriously attacked by various diseases, which requires more and more information for immune relevant genes on genome background. Recently, high-throughput RNA sequencing (RNA-seq technology provides a powerful and efficient method for transcript analysis and immune gene discovery. METHODS/PRINCIPAL FINDINGS: A cDNA library from hepatopancreas of E. sinensis challenged by a mixture of three pathogen strains (Gram-positive bacteria Micrococcus luteus, Gram-negative bacteria Vibrio alginolyticus and fungi Pichia pastoris; 10(8 cfu·mL(-1 was constructed and randomly sequenced using Illumina technique. Totally 39.76 million clean reads were assembled to 70,300 unigenes. After ruling out short-length and low-quality sequences, 52,074 non-redundant unigenes were compared to public databases for homology searching and 17,617 of them showed high similarity to sequences in NCBI non-redundant protein (Nr database. For function classification and pathway assignment, 18,734 (36.00% unigenes were categorized to three Gene Ontology (GO categories, 12,243 (23.51% were classified to 25 Clusters of Orthologous Groups (COG, and 8,983 (17.25% were assigned to six Kyoto Encyclopedia of Genes and Genomes (KEGG pathways. Potentially, 24, 14, 47 and 132 unigenes were characterized to be involved in Toll, IMD, JAK-STAT and MAPK pathways, respectively. CONCLUSIONS/SIGNIFICANCE: This is the first systematical transcriptome analysis of components relating to innate immune pathways in E. sinensis. Functional genes and putative pathways identified here will contribute to better understand immune system and prevent various diseases in crab.

  4. Effect of replacing dietary fish oil with soybean oil on growth, non-specific immune response, and resistance to Aeromonas hydrophila challenge in Chinese mitten crab, Eriocheir sinensis%豆油替代鱼油对中华绒螯蟹幼蟹生长、非特异性免疫和抗病力的影响

    Institute of Scientific and Technical Information of China (English)

    陈彦良; 李二超; 禹娜; 田文静; 江星; 孙立梅; 齐霁; 陈立侨

    2014-01-01

    Traditionally, fish oil is the main lipid source in the feed for most species in aquaculture owing to its effective supply of energy and high content of essential fatty acid. The fatty acid especially n-3 HUFA from the fish oil had also been proved to have positive effect on maintaining the immune system. However, the decline of fish oil production from wild fisheries has resulted in a supply shortage and price escalation of fish oil. Therefore, it has been a major challenge to find viable sources of oil to substitute fish oil. Among available vegetable oils, soybean oil has been widely chosen due to its availability, price and abundant content of fatty acid. In this study, we evaluated the effects of diets with different fish oil and soybean oil ratios on grouth, non-specific immune response and disease resistance in Chinese mitten crab (Eriocheir sinensis). Five isonitrogenous and isoenergetic diets were for-mulated in which 0%(control:F1), 25%, 50%, 75%, or 100%(F2-F5) of the fish oil was replaced with soybean oil. Juvenile crabs (mean weight 0.27±0.03 g) were assigned to one of five treatment groups (four replicates per group) and fed one of the diets for 42 d. There was no significant difference in the survival rate among the treatments (P>0.05). The weight gain was significantly higher in the F4 group than in the F1 group (P0.05). Serum PO (phenoloxidase) activity was higher in F4 and lower in F5 than the other groups (P0.05). After the feeding experiment, the crabs were infected with Aeromonas hydrophila for 10 d. The first death was recorded in F5, and the crabs in F5 had significantly higher cumulative mortality than those in F1 and F4 (P0.05). In conclusion, complete substitu-tion of fish oil with soybean oil did not affect growth performance, but did reduce the ability to resist disease. Our re-sults suggest that replacement of 75%fish oil with soybean oil in the diet of Chinese mitten crab can improve growth with little effect on disease resistance.%

  5. STUDIES ON THE SIGNALING PATHWAY OF CpG ODNs ACTIVATING proPO SYSTEM IN CHINESE MITTEN CRAB ERIOCHEIR SINENSIS%CpG寡脱氧核苷酸触发中华绒螯蟹酚氧化酶原系统信号传导途径的研究

    Institute of Scientific and Technical Information of China (English)

    李红霞; 俞菊华; 李义; 徐跑

    2011-01-01

    为探讨CpG寡脱氧核苷酸(CpG-oligodeoxynucleotides,CpG-ODN)激活中华绒螯蟹血细胞酚氧化酶原系统(prophenoloxidase system,proPO系统)的信号传导途径,使用一定剂量的CpGODN-1670、ODN-R以及几种细胞信号传导的激活剂或抑制剂体外处理中华绒螯蟹血细胞,通过检测胞内外酚氧化酶(PO)活性的变化,对CpG ODN触发proPO激活系统的信号传导途径进行评价.结果显示,ODN-1670与ODN-R均可触发蟹血细胞proPO激活系统,试验剂量的ODN-1670可促进血细胞内外已有的proPO转化为PO,而对proPO颗粒的释放具有一定的抑制作用;ODN-R则不仅可使proPO转化为PO,还可促进血细胞脱颗粒.两者的信号传导途径相似,可能都包含了G-蛋白介导的蛋白激酶C(PKC)途径,酪氨酸蛋白激酶(RTK)途径对ODN-1670的触发proPO激活系统的活化过程进行负调控.%Prophenoloxidase system (proPO system) plays a key role in the natural immune response of Crustacean animals,but the signal transduction pathway of proPO system is rarely reported.CpG- oligodeoxynucleotides (CpG-ODN) is synthetic oligodeoxynucleotide containing CpG motif that could simulate the bacterial DNA with immunostimulatory activity.Many studies has proved that it is a kind of good non-specificity immunostimulants and specific immunology adjuvant.CpG ODNs could stimulate the proPO system in haemocytes of Macrobrachium rosenbergii, but so far, it has not yet seen a similar study reported in the Chinese mitten crab (Eriocheir sinensis) at home and abroad.The experiment were processed in order to determine the signal transduction pathway involved in the CpG ODNs activating proPO system in Chinese mitten crab (Eriocheir sinensis).The crab haemocytes cultured in M-199 medium was treated in vitro with different concentrations of CpG ODN-1670 and ODN-R, as following, 0, 5, 10, 15, 20 and 25 μg/mL.Then we detected the effects on the proPO system of several activators or inhibitors for specific

  6. 普通棉籽粕和发酵棉籽粕替代鱼粉对中华绒螯蟹幼蟹生长性能、体成分及肝胰腺消化酶活性的影响%Effects of Fish Meal Replacement by Common Cottonseed Meal and Fermented Cottonseed Meal on Growth Performance, Body Composition and Hepatopancreas Digestive Enzyme Activities of Juvenile Chinese Mitten Crab (Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    杨霞; 叶金云; 张易祥; 吴成龙; 刘沛; 王伟

    2014-01-01

    This experiment was conducted to investigate the effects of fish meal replacement by common cot-tonseed meal ( CSM) and fermented cottonseed meal ( FCSM) on growth performance, body composition and hepatopancreas digestive enzyme activities of juvenile Chinese mitten crab ( Eriocheir sinensis) . A total of 660 juvenile Chinese mitten crab with the average body weight of (0. 56 ± 0. 04) g were randomly assigned to 11 groups with 3 replicates per group and 20 crab per replicate. Eleven isonitrogenous (38. 39% crude protein) and isocaloric (19. 18 MJ/kg gross energy) experimental diets were formulated in which CSM supplemental levels were 0 , 8 . 0%, 16 . 0%, 24 . 0%, 32 . 0% and 40 . 0% ( named as groups CSM0 , CSM8 , CSM16 , CSM24, CSM32 and CSM40, respectively), and FCSM supplemental levels were 8. 0%, 16. 0%, 24. 0%, 32 . 0% and 47 . 5% ( named as groups FCSM8 , FCSM16 , FCSM24 , FCSM32 and FCSM47 . 5 , respective-ly) , respectively. The experiment lasted for 6 weeks. The results showed as follows: compared with the con-trol group ( group CSM0 ) , the weight gain rate, specific growth rate and survival rate of crab in groups CSM8 , CSM16 , FCSM8 , FCSM16 and FCSM24 had no significant differences ( P>0 . 05 ) . The whole crab crude protein content in groups CSM8 , FCSM8 , FCSM16 and FCSM24 also had no significant difference compared with the control group (P >0. 05). The weight gain rate, specific growth rate, survival rate and whole crab crude protein content were significantly lower than those in control group when CSM supplemental level was over 16% or FCSM supplemental level was over 24% ( P0. 05). With the increase of the replacement level of CSM or FCSM, the activities of hepatopan-creas pepsin and trypsin were declined gradually, while the activities of amylase and cellulose were increased gradually. Under the same replacement level, the activities of pepsin and trypsin in groups FCSM were higher than those in groups CSM in different degrees, and the

  7. 长江、黄河、辽河水系中华绒螯蟹野生扣蟹的形态学及生化组成%Comparative studies of the morphology and biochemical composition of wild juvenile Chinese mitten crabs from the Yangtze River, Yellow River and Liaohe River systems

    Institute of Scientific and Technical Information of China (English)

    卢义; 吴旭干; 何杰; 王春; 李晓东; 刘乃更; 王幼鹏; 成永旭

    2016-01-01

    The Chinese mitten crab,Eriocheir sinensis, is an important aquaculture species in China that is widely dis-tributed in the east Pacific coast of China, from 24°N northwards to the Korean Peninsula, 42–43°N, from 112° to 114°E. Its high market demand, favorable taste and significant advances in hatchery and grow-out techniques have resulted in this crab being cultured widely in ponds, reservoirs and lakes throughout China since the 1990s. As a consequence, aquaculture yields have steadily increased over the past decades, from 8000 t in 1991 to approximately 729900 t in 2013. The main culture areas are located in the three principal drainage basins, i.e. the Liaohe, Yellow and Yangtze Rivers. The Yangtze delta is the largest culture area among the three drainage basins. Although pond-reared populations of E. sinensisoriginated from their native habitats, i.e. the Liaohe, Yellow and Yangtze Rivers, the Yangtze population generally had the largest body size of adult crabs, the best growth performance and the best taste among three populations. Therefore, pond-reared populations ofE. sinensis, originating from the wild Yangtze population, have become the common and major culture population in Middle and East China. Inbreeding depression and adverse selec-tion for smaller-sized crabs eventually resulted in the genetic degeneration of pond-rearedE. sinensis. Moreover, the blind introduction and culture of different populations ofE. sinensisin their native habitat has led to hybrid germplasms for pond-reared populations. Previous studies have shown that wild crab seeds of juvenileE. sinensisshowed different culture performance in ponds, and the wild crab seeds from the Yangtze River system generally had the best perform-ance and attracted the highest price among these wild populations. However, to date, there is no reliable discrimination method to identify the origins of wild crab seeds from different rivers. Therefore, the current study was designed to in

  8. Comparison of Three Aquaculture Models of Chinese Mitten Rrab in Tuo Lake%沱湖河蟹养殖模式比较研究

    Institute of Scientific and Technical Information of China (English)

    鲍方印; 肖明松; 周斌; 訾士波; 崔峰; 王松

    2014-01-01

    Three aquaculture models such as traditional diet model ,snails and plants feeding model ,Chinese mitten crab and bighead carp polyculture model were employed to compare the economic benefit.The physical and chemical indicators of water under the three models were compared.The results showed the economic benefits of Chinese mitten crab and bighead carp polyculture model was higher.The fresh water snail and plants polyculture model could maintain water ecological balance and improve water quality.%采用传统饲料喂养、螺类水草喂养和蟹鳙混合放养3种模式,比较其经济效益,观测水体理化指标,结果表明,蟹鳙混养经济效益较高,采用投喂螺类和水草能调节水体生态环境,改善水质。

  9. Habitat recognition and grade evaluation of Chinese mitten crab (Eri-ocheir sinensis) using electronic nose%电子鼻在中华绒螯蟹产地鉴别及等级评定上的应用

    Institute of Scientific and Technical Information of China (English)

    顾赛麒; 王锡昌; 张晶晶; 毛健桢

    2014-01-01

    Electronic nose (E-Nose) technology was applied in this study to detect the aroma profile of abdomen, claw, leg meat and spawn of Eriocheir sinensis, which were farmed in Yangcheng Lake, Songjiang and Chongming region within different grades. Results showed that the aroma profile of four edible parts of Yangcheng-Lake-crabs in three grades (special, first and second) could be distinguished well. Soft independent modeling of class analogy (SIMCA) method was applied to establish the recognizing model of Yangcheng-Lake-crabs either on one single part or on multi-ple parts. By a comparison, the model based on multiple parts turned out to be more effective. Rejection ratio of none-Yangcheng-Lake-crabs reached 100 percent. Meanwhile, a partial least squares regression (PLSR) model was also developed to evaluate the correlation between E-Nose responses and grade scores of Eriocheir sinensis. Correlation coefficient was 0.96, manifesting the PLSR model was able to predict grade scores of unknown crab samples.%采用电子鼻对阳澄湖、松江、崇明的不同等级中华绒螯蟹(Eriocheir sinensis)各可食部位香气轮廓进行了检测。特级、1级、2级阳澄湖中华绒螯蟹体肉、钳肉、足肉、性腺4部位香气轮廓区分显著。采用软独立建模的方法,分别建立了基于单部位及联合多部位的阳澄湖中华绒螯蟹产地鉴别模型,结果表明应用联合多部位模型,对非阳澄湖蟹的识别率达到100%。采用偏最小二乘回归法建立了电子鼻响应信号与中华绒螯蟹等级评分的回归模型,相关系数为0.96,表明基于此模型可判定中华绒螯蟹蟹样等级。

  10. 饲料中镁添加量对中华绒螯蟹幼蟹生长、体成分及抗氧化能力的影响%Effects of Magnesium Supplementation on Growth, Body Composition and Antioxidant Ability of Juvenile Chinese Mitten Crab (Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    田文静; 魏建军; 李二超; 禹娜; 吴强强; 陈立侨

    2015-01-01

    with the Mg supplementation of 7.5 g/kg and the group without Mg supplementation, re-spectively (P<0.05). The content of malonaldehyde (MDA) in hepatopancreas and serum was firstly de-creased and then increased with the increase of dietary Mg supplementation, and the lowest values were found in the group with the Mg supplementation of 3. 0 g/kg, which was significantly lower than that in the other groups ( P<0.05) . In conclusion, the L-aspartic acid magnesium as Mg source, the juvenile Chinese mitten crab have the better growth effect when Mg supplementation is 3.0 g/kg;the GSH content in hepatopancreas as criterion, base on the quadratic regression model fitting, the juvenile Chinese mitten crab have the best antioxi-dant ability when Mg supplementation is 3.76 g/kg ( dietary Mg content is 4.39 g/kg) .

  11. Genetic Differences of Mitten Crabs Based on RFLP Analysis on Mitochondrial Cytochrome Oxidase Subunit I (COI) Gene

    Institute of Scientific and Technical Information of China (English)

    HU Pengfei; WANG Qian; DAI Wei; WANG Xiaomei

    2008-01-01

    The genetic differences of 15 mitten crab populations from 6 river systems in mainland China and 1 population from Russia were studied based on RFLP analysis of mitochondrial cytochrome oxidase subunit I (COI).The results showed that Tas I-RFLP pattern could be used as a genetic marker to distinguish Eriocheir hepuensis from Eriocheir sinensis, Eriocheirjaponica and Eriocheir leptognathus;genetic distances among 13 populations ofEriocheir sinensis range from 0 to 0.015, indicating that they were different geographic strains;the subspecies status ofEriocheir sinensis and Eriocheir hepuensis (population from Nanliujiang) were considered owning to their genetic distances of 0.02-0.044,indicating that genetic divergence between them was low; Eriocheir leptognathus (population from Nanpaihe, Tianjin) was the most distant taxon with genetic distances value of 0.147-0.195,which could be defined as genetic distances between species in genus Eriocheir.

  12. Three-dimensional observation and dynamics analysis of Chinese mitten crab’s locomotion on smooth terrain%中华绒螯蟹平面运动三维观测和动力学分析

    Institute of Scientific and Technical Information of China (English)

    张晓冬; 李建桥; 邹猛; 张锐; 李因武

    2013-01-01

      为给适应复杂路面的多足仿生机器人或步行移动平台的研究提供理论依据,该文以中华绒螯蟹为研究对象,使用三维运动图像采集系统采集其运动图像,并使用三维运动图像分析系统得到中华绒螯蟹质心的运动学参数,分析结果表明:中华绒螯蟹在平面运动时主要使用跳跃步态;质心动能、重力势能以及总机械能呈正弦波动,动能与重力势能同相;使用恢复系数表示动能和重力势能相互转换的效率,其平均值为31.73%±17.29%,恢复系数和平均速率没有相关关系;质心机械能比质量功率随平均速率的增长呈线性增加;质心水平动能比质量功率和重力势能比质量功率对中华绒螯蟹身体的加速和抬升起主要作用。该研究可为研究适应复杂路面的仿生机器人或移动平台提供理论依据。%Some types of arthropods can go through rugged terrains high-efficiently and stably, which gives us innovative ideas and adequate theories for designing bionic legged-robots or mobile platforms. Therefore, the biomechanics analysis of legged-animals during their locomotion on a terrain is highly significant in many biological or biorobotics disciplines. The locomotion mechanism of the Chinese mitten crab, which originated from the Far East and predominantly lived along rocky shores or in freshwater, as a typical arthropod, was studied using the experimental methods of biomechanics. In the present study, 30 tested Chinese mitten crabs (Eriocheir sinensis Milne-Edwards) were collected from Yangcheng Lake in China. The body mass of the crabs was measured with an electronic balance (accuracy=0.001 g) and the location of the center of mass on the dorsal carapace for each crab was determined with a suspended test. In order to capture the video images of the movements of Chinese mitten crabs’ locomotion on a smooth terrain, we designed a high speed 3-D (three-dimension) including

  13. 亚硝酸盐急性胁迫对中华绒螯蟹幼体相关免疫指标和应激蛋白(HSP70)表达的影响%Effects of Acute Nitrite Exposure on Immunity Indicators and HSP70 Expression in Chinese Mitten-hand Crab (Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    洪美玲; 陈立侨; 孙新谨; 李二超; 顾顺樟; 禹娜

    2011-01-01

    为探讨亚硝酸盐急性胁迫对中华绒螯蟹机体免疫力的影响,以及机体在胁迫过程中的应对策略,分别测定了幼蟹(平均体重3.25 g)在10、20、30、40 mg L-1业硝酸盐暴露组和对照组中血细胞总数(Total hemocyte counts,THC)、超氧化物歧化酶( Superoxide dismutase,SOD)活力、丙二醛(Malodiadchydc,MDA)含量以及热休克蛋白 70( Heat stress protein 70,HSP70)表达量在受胁迫2d内的动态变化.结果表明:1)低浓度亚硝酸盐(10 mg L-1)胁迫组THC在胁迫3h时显著高于对照组,肝胰腺中SOD活性在胁迫3h和6h时亦显著提高,表现出一定的“毒物兴奋效应”2)但随着暴露时间的延长和亚硝酸盐浓度的升高,幼蟹THC减少,肝胰腺SOD活性下降,而MDA含量升高3)对照组中有少量的HSP70表达.幼蟹经10、20 mg L-1亚硝酸盐处理后,鳃组织中HSP70表达量在胁迫6h后达到最大,而经30、40 mg L-1 亚硝酸盐处理后,HSP70表达量在胁迫3h后达到最大.各浓度组所诱导的HSP70最大表达量与水中亚硝酸盐的浓度呈正相关.以上结果说明亚硝酸盐胁迫可通过加剧组织中脂质过氧化的方式导致机体免疫力下降,肝胰腺中MDA的含量变化可作为业硝酸盐胁迫的有效评价指标之一,而HSP70表达量的变化可作为早期预警指标应用于亚硝酸盐胁迫评价中.图2表1参36%Nitrite is an intermediate product either in the bacterial nitrification of ammonia, or in the bacterial denitrification of nitrate. The concentration of nitrite may reach 50 mg L-1 in intensive aquacultural systems due to an imbalance in biofilter resulting from overcrowding effect and poor water recirculation. High levels of nitrite in water were potential factors triggering stress on aquatic organisms. The sensitive indicators of stress evaluation for the Chinese mitten-hand crab Eriocheir smensis were selected to investigate the effect of ambient nitrite on the immunity response. In this experiment, the

  14. Review on the osmoregulation and adaptation to salinity changes of Chinese mitten crab Eriocheir sinensis%中华绒螯蟹对盐度变化的适应及其渗透压调节的研究进展

    Institute of Scientific and Technical Information of China (English)

    王悦如; 李二超; 龙丽娜; 禹娜; 张凤英; 陈立侨

    2011-01-01

    Most Decapods species of the crustacean have comprehensive capacity of osmoregulation, and can adapt to a wide range of ambient salinties. It is significant to further understand the underlying mechanisms of their comprehensive ability of ambient salinities and helpful for the inland culture of some marine species by studying the osmoregulation and adaptive capacity of these species to ambient salinity changes. Chinese mitten crab, Eriocheir sinensis, has been well studied in many aspects related to the physiological responses to ambient salinity changes, and many useful literatures and findings have been accumulated. Therefore, E. Sinensis could be regarded as an animal model for researching on osmoregulation mechanism of Decapods species.The current research on osmoregulation of E. Sinensis is reviewed in the following aspects: 1) Effects of salinity on development, growth and energy metabolism of E. Sinensis. At present, effects of salinity on larval development, growth and survival rates of different periods of larva and juvenile E. Sinensis have been studied. Larval development of E. Sinensis needs saline water, and therefore it can tolerate certain levels of ambient salinity. From zoea to megalopa, the salinity tolerance gradually increases. And at the juvenile period, they are able to adapt to freshwater environment. All these results can provide reference for juvenile crab cultivation. Respiration and excretion are basic physiological activities of energy metabolism in animals, and can reflect the physiological status of animals. Changes of environmental conditions( such as salinity) can lead to changes of energy metabolism, which is reflected by changes of oxygen consumption rate, C02 production rate, ammonia-N excretion rate, 0/N ratio, respiratory quotient and C/N ratio etc; 2) Osmoregulation organs; gills are very important organs and play a prominent role in osmoregulation and ion transport. Antennal gland also can regulate the osmotic pressure, and

  15. Review on the osmoregulation and adaptation to salinity changes of Chinese mitten crab Eriocheir sinensis%中华绒螯蟹对盐度变化的适应及其渗透压调节的研究进展

    Institute of Scientific and Technical Information of China (English)

    王悦如; 李二超; 龙丽娜; 禹娜; 张凤英; 陈立侨

    2011-01-01

    Most Decapods species of the crustacean have comprehensive capacity of osmoregulation, and can adapt to a wide range of ambient salinties. It is significant to further understand the underlying mechanisms of their comprehensive ability of ambient salinities and helpful for the inland culture of some marine species by studying the osmoregulation and adaptive capacity of these species to ambient salinity changes. Chinese mitten crab, Eriocheir sinensis, has been well studied in many aspects related to the physiological responses to ambient salinity changes, and many useful literatures and findings have been accumulated. Therefore, E. Sinensis could be regarded as an animal model for researching on osmoregulation mechanism of Decapods species.The current research on osmoregulation of E. Sinensis is reviewed in the following aspects: 1) Effects of salinity on development, growth and energy metabolism of E. Sinensis. At present, effects of salinity on larval development, growth and survival rates of different periods of larva and juvenile E. Sinensis have been studied. Larval development of E. Sinensis needs saline water, and therefore it can tolerate certain levels of ambient salinity. From zoea to megalopa, the salinity tolerance gradually increases. And at the juvenile period, they are able to adapt to freshwater environment. All these results can provide reference for juvenile crab cultivation. Respiration and excretion are basic physiological activities of energy metabolism in animals, and can reflect the physiological status of animals. Changes of environmental conditions( such as salinity) can lead to changes of energy metabolism, which is reflected by changes of oxygen consumption rate, C02 production rate, ammonia-N excretion rate, 0/N ratio, respiratory quotient and C/N ratio etc; 2) Osmoregulation organs; gills are very important organs and play a prominent role in osmoregulation and ion transport. Antennal gland also can regulate the osmotic pressure, and

  16. Effects of pH stress on five non-specific immune parameters of Chinese mitten crab (Eriocheir sinensis)%pH胁迫对中华绒螯蟹5种非特异性免疫指标的影响

    Institute of Scientific and Technical Information of China (English)

    孙汉; 李义; 王玥; 郭明凯; 俞泉宇

    2011-01-01

    测定了不同pH(4.5,6.0,7.5,9.0,10.5)胁迫1、4、7、10d后中华绒螯蟹(Eriocheir sinensis)血细胞呼吸爆发(RP)、血细胞破碎物上清液(HLS)酚氧化酶(PO)、血清溶菌酶(LSZ)、酸性磷酸酶(ACP)及碱性磷酸酶(ALP)活性的变化.结果表明:在pH胁迫后第1天,pH4.5组的RP活性显著高于对照组(pH 7.8)和碱性胁迫的3个组,pH 6.0组的PO活性显著高于对照组、pH7.5组和pH 9.0组,pH 10.5组的ACP活性显著高于对照组,pH 6.0组的ALP活性显著高于对照组和碱性胁迫的3个组(P<0.05);在pH胁迫后第7天,pH 6.0组的RP活性显著高于pH 10.5组,pH4.5组的PO活性显著低于对照组和pH 10.5组(P<0.05);血清LSZ对pH胁迫较为敏感,在胁迫后第1天,pH 9.0组显著低于对照组,在胁迫后第4、7、10天,pH4.5、6.0、9.0、10.5组均显著低于对照组(P<0.05).由此可见,RP、PO、LSZ、ACP和ALP可作为pH胁迫对中华绒螯蟹免疫力影响的重要指标.%The changes of immune factors were examined including the activities of respiratory burst ( RP) of haemocyte, phenoloxidase (PO) in haemocyte lysate supernatant (HLS) , lysozyme (LSZ) , acidic phosphatase (ACP) and alkaline phosphatase (ALP) in serum of Chinese mitten crab (Eriocheir sinensis) at 1, 4, 7 and 10 days after different pH (4. 5, 6. 0, 7. 5, 9. 0, 10. 5) stress. The results indicated under 1 day pH stress that the activities of RP in the group of pH 4. 5 were significantly higher than that in control group (pH 7.8) and three alkaline pH stress groups, the activities of PO in the group of pH 6. 0 were significantly higher than that in control group and in the groups of pH 7. 5 and pH 9. 0, the activities of ACP in the group of pH 10.5 were significantly higher than that in control group, the activities of ALP in the group of pH 6. 0 were significantly higher than that in the control group ( pH 8. 0) and in three alkaline pH stress groups (P < 0. 05). Under 7 days pH stress the activities of RP in the

  17. Effects of Fish Oil Replacement by Blending Vegetable Oils in Fattening Diets on Gonadal Development, Lipid Metabolism, Antioxidant and Immune Capacities of Adult Male Chinese Mitten Crab (Eriocheir sinensis)%育肥饲料中混合植物油替代鱼油对中华绒螯蟹成体雄蟹性腺发育、脂质代谢、抗氧化及免疫性能的影响

    Institute of Scientific and Technical Information of China (English)

    赵磊; 龙晓文; 吴旭干; 刘泽华; 何杰; 成永旭

    2016-01-01

    In order to investigate the effects of fish oil replacement by blending vegetable oils on gonadal devel-opment, lipid metabolism, antioxidant and immune capacities of adult male Chinese mitten crab ( Eriocheir sinensis) , five isonitrogenous and isolipidic fattening diets with 39.5%crude protein and 14.0%crude lipid were formulated to replace 0, 25%, 50%, 75%and 100%of fish oil ( named diets 1#, 2#, 3#, 4# and 5#, respectively) with blending vegetable oils ( soybean oil∶rapeseed oil=1∶1) .Therefore, there were five groups in this study and each group had four replicates ( each replicate with 25 crabs) for the culture of male crabs. The experiment lasted for 60 days in outdoor pond.The results showed as the follows: 1) different levels of fish oil replacement by blending vegetable oils had no significant effects on gonadosomatic index ( GSI ) and hepatosomatic index (HSI) of male E.sinensis (P>0.05).2) The lowest content of triglyceride (TG) in hepatopancreas was detected in diet 1# group, while there were no significant differences in the contents of hepatopancreas TG and total cholesterol ( TC) among the other groups ( P>0.05) .Except for the contents of free cholesterol ( FC) and high density lipoprotein cholesterol ( HDL-C) , the serum lipid metabolism indices in diet 2# group were significantly higher than those in other groups ( P0.05) .For the immune indices in the hepatopancreas, the highest activities of alkaline phosphatase ( ALP) and acid phos-phatase ( ACP) were found in diet 1# group;diet 4#group had the highest activity of γ-glutamyl transpeptid-ase (γ-GT) , diet 1# group took second place, and diet 2# group was the worst.4) The highest ALP activity in the serum was detected in diet 3# group, and significantly higher than that in diet 1# and 4# groups ( P0.05) . The serum hemocyanin ( Hc) content, T-AOC and SOD activity in diet 2#group were significantly higher than those in other groups ( P<0.05) , while the lowest serum POD activity and MDA

  18. Evaluation on aroma-quality of meat,of Chinese mitten handed crab(Eriocheir sinensis) by principal component analysis and cluster analysis%基于主成分分析和聚类分析评价中华绒螯蟹蟹肉香气品质的研究

    Institute of Scientific and Technical Information of China (English)

    顾赛麒; 王锡昌; 陶宁萍; 张晶晶; 吴娜

    2012-01-01

    HS-SPME-GC-MS(Headspace solid phase micro-extraction coupled with gas chromatography and mass spectrometry) technology was applied to detect the aroma compounds from various edible parts (abdomen,claw and leg) of female Yangcheng-Lake-crabs in different grades(special,first and second). An internal standard (TMP) was introduced to quantitate the concentrations of aroma compounds and the concentration data were analyzed by principal component analysis(PCA) and cluster analysis(CA) methods. PCA results showed that,claw and leg meat from three grades,all acquired positive S-scores(except claw meat from second grade) and could be assumed to have the better aroma-quality. Meanwhile,alcohols, ketones,furans,N-containings and aromatics had been found out to be the five characteristic aroma species which related and contributed a lot to "better quality of aroma". With a unified consideration of edible part factor,it was found that higher grades of crabs resulted in better quality of aroma. However,claw meat acquired higher S-scores than abdomen meat and lower S-scores than leg meat. CA results showed that, aroma profile of abdomen and leg meat from three grades could be classified as one cluster. Similarly, alcohols,furans,ketones,N-containings and aromatics were in one cluster due to their high similarities. As a conclusion,consistency existed between PCA and CA results,indicating these two methods might mutual supply each other and could be used to establish a model for evaluating aroma-quality of crabmeat.%摘要:运用顶空固相微萃取-气-质联用技术.对采自阳澄湖的特级、1级、2级的雌性中华绒螯蟹体肉、钳肉和足肉中的香气成分进行了鉴定并以内标法对其定量。通过主成分分析法(PCA)和聚类分析法(CA)对不同蟹肉样品的香气品质进行评价。主成分分析结果显示:不同等级中华绒螯蟹钳肉和足肉的综合得分均大于零(2级-钳肉除外),香气品质较好,醇

  19. 中华绒螯蟹延伸因子EF-1δ基因全长cDNA克隆及表达%The full length cDNA cloning and expression of elongation factor 1δ from the Chinese mitten crab(Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    郭子好; 杨志刚; 刘志伟; 王瑶; 杨筱珍; 成永旭

    2012-01-01

    Elongation factor (EF) is a protein factor which plays roles in the peptide chain elongation in the process of protein synthesis, including elongation factor 1( EF-1) and elongation factor 2(EF-2). Elongation factor 1 consists of four subunits a, p, y and 8, and plays a key role in protein translation process. In this study, we cloned EF-1δ gene from Eriocheir sinensis using reverse transcriptase polymerase chain reaction (RT-PCR) and rapid-amplification of cDNA ends (RACE), and primers were designed according to the conserved sequence of elongation factor-1δ from Xenopus laevis. The full-length cDNA sequence of EF-1δ is 933 bp which codes 263 amino acid residues. And comparison results showed that the nucleotide homology of EF-1δ was 70% similar to Xenopus laevis and amino acid homology of EF-1δ was 54% similar to Danaus plexippus, using BLASTN and BLASTX software. The phylogenetic analysis based on amino acid sequence shows that EF-1δ has highest similarity with EF-1δ of Lepeophtheirus salmonis. The expression of the gene in different tissues and stages of E. sinensis was analyzed by real-time fluorescent quantitative PCR. The result showed the EF-1δ mRNA was mainly detected in muscle and small amount in testis, hepatopancreas and trace in heart, ovary, stomach, intestine, gill. EF-1δ mRNA was detected with high level in muscles compared to hepatopancreas and gill in different developmental states of the crab, and displays significant difference at P<0.05. It also has significant difference at P<0.05 between muscles in different developmental states, and it was detected the highest expression in precocious crab, followed by mature crab and by a lower expression of crablet; And there is no significant expression difference between hepatopancreas and gill tissues in different developmental states.%根据非洲爪蟾延伸因子-1δ(elongation factor-1δ,EF-1δ)基因的保守序列设计引物,采用逆转录聚合酶链反应(RT-PCR)以及cDNA末端

  20. MMSE-GC-O结合OAV法鉴定蒸制崇明地区中华绒螯蟹中关键气味物质%Characterization of key odor compounds in steamed Chinese mitten crab (Eriocheir sinensis) farmed in Chongming region by monolithic material sorptive extraction-gas chromatography-olfatometry and odor activity value methods

    Institute of Scientific and Technical Information of China (English)

    顾赛麒; 吴娜; 张晶晶; 吉思茹; 陶宁萍; 王锡昌

    2014-01-01

    Objective To analyze the volatile compounds in different edible parts of steamed male E. si-nensis farmed in Chongming region, select the key odor compounds (KOCs) from all the volatiles, and finally offer some theoretical basis to explain its outstanding flavor. Methods Seven adsorption rods made of Mono-Trap RCC18 were applied to extract the volatile compounds of 5 g crab sample under 100℃for 50 min under a headspace extraction mode. Those volatiles of crab samples were then separated and identified by GC-MS and quantified by an internal standard method. In order to select the KOCs from all the volatiles, a combination of GC-O and OAV methods were also employed. Results A total of 71 volatiles were finally identified in male E. sinensis farmed in Chongming region, among which 50, 48, 52 and 60 volatiles were identified in the abdomen, claw, leg meat and the gonad part, respectively. 19 KOCs were successfully selected from all 71 volatiles. Among them, 6 main key odor compounds (MKOCs), with an odor intensity value (OIV) over three and an odor activity value (OAV) over ten, were eventually obtained. Trimethylamine (fishy) was the only MKOC in all four parts. Besides, benzaldehyde (almond-like) and (Z)-4-heptenal (fishy) were the MKOC in the abdomen meat and leg meat, respectively. 3 MKOCs were found in the gonad part, including hexanal (grassy), 1-octen-3-ol (mushroom) and nonanal (grassy). Conclusion Six MKOCs were verified to have relative high odor activities by both OAV and GC-O methods. Those MKOCs might represent the key odor characteristics of different edible parts of male E. sinensis farmed in Chongming region. However, the task of revealing forma-tion mechanism for these MKOCs remains to be carried out in the future.%目的:分析蒸制雄性崇明地区中华绒螯蟹不同可食部位的挥发性成分,筛选关键气味物质,为解析其优良风味提供理论依据。方法采用7个MonoTrap RCC18吸附子在100℃下对5 g样品顶空萃取50

  1. Fatty Acid Binding Proteins FABP9 and FABP10 Participate in Antibacterial Responses in Chinese Mitten Crab, Eriocheir sinensis

    OpenAIRE

    Lin Cheng; Xing-Kun Jin; Wei-Wei Li; Shuang Li; Xiao-Nv Guo; Juan Wang; Ya-Nan Gong; Lin He; Qun Wang

    2013-01-01

    Invertebrates rely solely on the innate immune system for defense against pathogens and other stimuli. Fatty acid binding proteins (FABP), members of the lipid binding proteins superfamily, play a crucial role in fatty acid transport and lipid metabolism and are also involved in gene expression induced by fatty acids. In the vertebrate immune system, FABP is involved in inflammation regulated by fatty acids through its interaction with peroxidase proliferator activate receptors (PPARs). Howev...

  2. 我国蟹类土池育苗技术研究进展%Progress of the crab seed cultivation in earthen pond in China

    Institute of Scientific and Technical Information of China (English)

    顾孝连; 乔振国

    2012-01-01

    Crab culture has become one of pillar industries in China' s aquculture industry. Chinese mitten crab ( Eriocheir sinensis) , swimming crab ( Portunus trituberculatus ) and mud crab ( Scylla paramamosain ) are three main culture species in China. Seed cultivation in earthen pond, as a mature technology, is widely used in seed culture practice in Chinese mitten crab and swimming crab, and has played an important role in culture. On the contrary, successful seed cultivation in earthen pond in mud crab has not been reported before. In this paper, the progress in larvae cultivation in these three crabs were reviewed. Key technique of larvae cultivation in earthen pond in Chinese mitten crab and swimming crab were analyzed. The feasibility of the technique of larvae culture in earthen pond to be used in the mud crab was discussed.%蟹类养殖产业已成为我国水产养殖的支柱产业之一.中华绒螯蟹(Eriocheir sinensis,以下简称河蟹)、三疣梭子蟹(Portunus trituberculatus,以下简称梭子蟹)、拟穴青蟹(Scylla paramamosain,以下简称青蟹)是我国主要的养殖蟹类.目前3种蟹类土池育苗技术发展不平衡,河蟹、梭子蟹土池育苗技术较为成熟,已经普及推广并在养殖生产中发挥重要作用;青蟹土池育苗尚未有成功的报道.本文综述了我国河蟹、梭子蟹、青蟹苗种生产技术,尤其是土池育苗技术的研究进展,并对河蟹、梭子蟹土池育苗关键技术进行分析,旨在探讨蟹类土池育苗技术应用于青蟹土池育苗的可行性.

  3. 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.

  4. Understanding to Hierarchical Microstructures of Crab (Chinese hairy) Shell as a Natural Architecture

    International Nuclear Information System (INIS)

    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

  5. Multi-purpose tool mitten

    Science.gov (United States)

    Wilcomb, E. F.

    1969-01-01

    Tool mitten provides a low reaction torque source of power for wrench, screwdriver, or drill activities. The technique employed prevents the attachments from drifting away from the operator. While the tools are specifically designed for space environments, they can be used on steel scaffolding, in high building maintenance, or underwater environments.

  6. Food web structure and trophic levels in polyculture rice-crab fields

    Science.gov (United States)

    Guo, Kai; Zhao, Wen; Li, Wenkuan; Zhao, Yuansong; Zhang, Peng; Zhang, Chen

    2015-05-01

    Stable carbon and nitrogen isotopes were used to investigate nutrient pathways and trophic relationships from the rice-crab system in Panjin, Liaoning Province, China. Values of δ13C ranged from -27.38‰±0.44‰ to -18.34‰±0.26‰ and δ15N ranged from 1.10‰±0.88‰ to 9.33‰±0.57‰. Pseudorasbora parva (Stone moroko) had the highest δ13C and δ15N values. The lowest δ13C values were obtained for the macrophytes and the lowest δ15N value was found in sediments. Stable carbon and nitrogen isotopes were used to determine the contribution of different food items to the diets of crabs. The δ13C results indicated that the Pseudorasbora parva made the greatest contribution to the diet of Eriocheir sinensis (Chinese mitten crab), while the δ15N results indicated that most food items contributed more than 10% to the diet of the crab. There were three trophic levels identified in the system (Levels 0-2). The crab Eriocheir sinensis, fish Pseudorasbora parva and Misgurnus anguillicaudatus (Oriental weatherfish), and the oligochaete Limnodrilus hoffmeisteri (Limnodrilus worm), were at the second level, zooplankton were at the first level and suspended particulate matter and macrophytes were at trophic position 0.

  7. Molecular cloning and tissue expression of the fatty acid-binding protein (Es-FABP gene in female Chinese mitten crab (Eriocheir sinensis

    Directory of Open Access Journals (Sweden)

    He Lin

    2010-09-01

    Full Text Available Abstract Background Fatty acid-binding proteins (FABPs, small cytosolic proteins that function in the uptake and utilization of fatty acids, have been extensively studied in higher vertebrates while invertebrates have received little attention despite similar nutritional requirements during periods of reproductive activity. Results Therefore, a cDNA encoding Eriocheir sinensis FABP (Es-FABP was cloned based upon EST analysis of a hepatopancreas cDNA library. The full length cDNA was 750 bp and encoded a 131 aa polypeptide that was highly homologous to related genes reported in shrimp. The 9108 bp Es-FABP gene contained four exons that were interrupted by three introns, a genomic organization common among FABP multigene family members in vertebrates. Gene expression analysis, as determined by RT-PCR, revealed the presence of Es-FABP transcripts in hepatopancreas, hemocytes, ovary, gills, muscle, thoracic ganglia, heart, and intestine, but not stomach or eyestalk. Real-time quantitative RT-PCR analysis revealed that Es-FABP expression in ovary, hemocytes, and hepatopancreas was dependent on the status of ovarian development, with peak expression observed in January. Conclusions Evidence provided in the present report supports a role of Es-FABP in lipid transport during the period of rapid ovarian growth in E. sinensis, and indirectly confirms the participation of the hepatopancreas, ovary, and hemocytes in lipid nutrient absorption and utilization processes.

  8. Gonad maturity in female Chinese mitten crab Eriocheir sinensis from the southern Baltic Sea – the first description of ovigerous females and the embryo developmental stage

    Directory of Open Access Journals (Sweden)

    Dagmara Wójcik

    2014-01-01

    Full Text Available This paper describes for the first time the gonad maturity stage of Eriocheir sinensis females (carapace width 55.20–78.10 mm collected in the autumns and winters of 2005–2012 in the Gulf of Gdańsk and Vistula Lagoon (southern Baltic Sea. Seventeen females had gonads in the penultimate stage, which indicates that spawning would shortly take place. Four other females had gonads in the last stage, which means they were already carrying eggs. These accounted, on average, for 17.9 ± 2.9% of female weight and were in the 3rd and 4th embryo developmental stage. The results show that the low salinity of southern Baltic Sea (≤ 7 PSU permits mating and fertilization as well as embryo development in E. sinensis. It is still not clear, whether such a salinity level will enable hatching and the complete larval cycle.

  9. Changes during late-stage embryonic development from egg-juvenile to free-living hatchling in Chinese freshwater crab Sinopotamon yangtsekiense (Decapoda, Brachyura,Potamidae)

    Institute of Scientific and Technical Information of China (English)

    XUE Junzeng; LIU Yan; Neil CUMBERLIDGE; WU Huixian

    2013-01-01

    This study expands on recent reports that direct development in the Chinese potamid freshwater crab Sinopotamon yangtsekiense involves the completion of all brachyuran larval stages (nauplius,zoea,and megalopa) inside the egg case during embryonic development.Detailed studies of embryonic development in this species revealed the presence of an additional larval stage (the egg-juvenile) between the megalopa and the free-living hatchling crab.We described and compared the appendages of the head,thorax,and abdomen of the egg-juvenile with those of the hatchling crab in S.yangtsekiense.Significant differences were found between most of the appendages of these two stages with a soft exoskeleton in the egg-juvenile,no joint articulation,a slimmer appearance,and a lack of setae when compared with the newly emerged free-living hatchling crab.These modifications of the appendages are related to the confinement within the egg case of the egg-megalopa and egg-juvenile during direct development,and the need for the free-living hatchling freshwater crab to move,feed,and respire.In marine crabs,the megalopa gives rise to the first crab stage whereas in freshwater crabs the egg-juvenile follows the megalopa and immediately precedes the free-living first crab stage.

  10. The Influence of Java Moss on the Growth of Early Juvenile Crab of Chinese Mitten Crab, Eriocheir sinensis%爪哇苔藓在河蟹早期仔蟹发育中的作用

    Institute of Scientific and Technical Information of China (English)

    吴仲庆

    2000-01-01

    研究了爪哇苔藓(Jubulajavenica)对河蟹(Eriocheirsinensis)早期仔蟹存活率和生长速度的影响.实验结果表明,投放爪哇苷藓的实验组存活率比无水草组高32.44%,平均体重增长快1.679倍.

  11. 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...

  12. Genome Sequence Analysis of CsRV1: A Pathogenic Reovirus that Infects the Blue Crab Callinectes sapidus Across Its Trans-Hemispheric Range.

    Science.gov (United States)

    Flowers, Emily M; Bachvaroff, Tsvetan R; Warg, Janet V; Neill, John D; Killian, Mary L; Vinagre, Anapaula S; Brown, Shanai; Almeida, Andréa Santos E; Schott, Eric J

    2016-01-01

    The blue crab, Callinectes sapidus Rathbun, 1896, which is a commercially important trophic link in coastal ecosystems of the western Atlantic, is infected in both North and South America by C. sapidus Reovirus 1 (CsRV1), a double stranded RNA virus. The 12 genome segments of a North American strain of CsRV1 were sequenced using Ion Torrent technology. Putative functions could be assigned for 3 of the 13 proteins encoded in the genome, based on their similarity to proteins encoded in other reovirus genomes. Comparison of the CsRV1 RNA-dependent RNA polymerase (RdRP) sequence to genomes of other crab-infecting reoviruses shows that it is similar to the mud crab reovirus found in Scylla serrata and WX-2012 in Eriocheir sinensis, Chinese mitten crab, and supports the idea that there is a distinct "Crabreo" genus, different from Seadornavirus and Cardoreovirus, the two closest genera in the Reoviridae. A region of 98% nucleotide sequence identity between CsRV1 and the only available sequence of the P virus of Macropipus depurator suggests that these two viruses may be closely related. An 860 nucleotide region of the CsRV1 RdRP gene was amplified and sequenced from 15 infected crabs collected from across the geographic range of C. sapidus. Pairwise analysis of predicted protein sequences shows that CsRV1 strains in Brazil can be distinguished from those in North America based on conserved residues in this gene. The sequencing, annotation, and preliminary population metrics of the genome of CsRV1 should facilitate additional studies in diverse disciplines, including structure-function relationships of reovirus proteins, investigations into the evolution of the Reoviridae, and biogeographic research on the connectivity of C. sapidus populations across the Northern and Southern hemispheres. PMID:26904003

  13. Geology and Origin of Europa's Mitten Feature (Murias Chaos)

    Science.gov (United States)

    Figueredo, P. H.; Chuang, F. C.; Rathbun, J.; Kirk, R. L.; Greeley, R.

    2002-01-01

    The "Mitten" (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several characteristics that suggest that the Mitten is distinct from typical chaos terrain and point to a different formational process. Photoclinometric elevation estimates suggest that the Mitten is slightly elevated with respect to the surrounding terrain; geologic relations indicate that it must have raised significantly from the plains in its past, resembling disrupted domes on Europa's trailing hemisphere. Moreover, the Mitten material appears to have extruded onto the plains and flowed for tens of kilometers. The area subsequently subsided as a result of isostatic adjustment, viscous relaxation, and/or plains loading. Using plate flexure models, we estimated the elastic lithosphere in the area to be several kilometers thick. We propose that the Mitten originated by the ascent and extrusion of a large thermal diapir. Thermal-mechanical modeling shows that a Mitten-sized plume would remain sufficiently warm and buoyant to pierce through the crust and flow unconfined on the surface. Such a diapir probably had an initial radius between 5 and 8 km and an initial depth of 20-40 km, consistent with a thick-lithosphere model. In this scenario the Mitten appears to represent the surface expression of the rare ascent of a large diapir, in contrast to lenticulae and chaos terrain, which may form by isolated and clustered small diapirs, respectively.

  14. 中华绒螯蟹血清凝集素的分离纯化与性质研究%Purification and Characteristics of Agglutinin in Serum of Chinese Mitten Crab Eriocheir sinensis

    Institute of Scientific and Technical Information of China (English)

    徐海圣; 徐步进

    2008-01-01

    运用硫酸铵盐析和GlcNAc-Sepharose 6B亲合层析等方法从中华绒螯蟹的血清中分离出一种天然的凝集素,经SDS-PAGE测得其分子量约为82 kD,由单一亚基组成,由等电聚焦凝胶电泳测得其等电点(pI)为5.4.糖凝集抑制试验中检测到葡萄糖、半乳糖、甘露糖、乳糖、果糖和蔗糖对中华绒螯蟹血清凝集素均没有抑制作用,但N-乙酰氨基糖GIcNAc、GalNAc和ManNAc等能抑制其凝集活性.热变性试验结果表明,温度为10~50℃,凝集素仍保持强的凝集活性,但温度升至60℃后,凝集活性迅速下降,至80℃失去凝集活性,在pH 4.0~8.0的各缓冲液中保持较强的凝集活性,而在此pH范围外,凝集活性均有不同程度的下降.中华绒螯蟹血清凝集素可使外源红血细胞发生凝集,还具有凝集细菌或抗菌作用.

  15. 中华绒螯蟹不同部位中活性香气物质的研究%Study on Aroma-active Compounds Profile from Different Edible Parts of Chinese mitten handed crab

    Institute of Scientific and Technical Information of China (English)

    顾赛麒; 王锡昌; 陶宁萍; 张晶晶; 吴娜

    2013-01-01

    HS-SPME-GC-MS (headspace solid phase micro-extraction coupled with gas chromatography and mass spectrometry) technology was applied in this study to identify the aroma compounds from abdomen,claw,leg meat and spawn of male Eriocheir sinensis cultured in Chongming region.A total of 58 volatiles,which can be divided into 8 classes,were identified in four edible parts and further quantitated based on internal standard analysis.Odor activity values (OAVs) of all 58 aroma compounds were calculated due to their thresholds.Fifteen key aroma-active compounds,such as decanal,were selected from all compounds and their OAVs were analyzed by both Principal Component Analysis (PCA) and Cluster Analysis (CA) methods.PCA result showed that the aroma-quality of spawn sample was better than others.8 aroma-active compounds including pentanal were determined as the characteristic compounds that contributed a lot to "better aroma-quality",among which 2,4-heptadienal played the most important role.CA result showed that the aroma profile of spawn could be classified as one cluster,so did the 8 aroma-active compounds including pentanal.The consistent results of PCA and CA analysis manifested that these two methods would support each other and be applied to establish a model for evaluating aroma-quality of Eriocheir sinensis in the future.%运用顶空固相微萃取-气-质联用技术(HS-SPME-GC-MS),对采自崇明的二级雄性中华绒螯蟹体肉、钳肉、足内和性腺中的香气成分进行了鉴定并以内标法对其定量.大闸蟹四可食部位中共检测到8大类58种香气物质,根据阈值进一步求得每种香气物质的活性值(OAV值).以OAV值为依据,从58种化合物中筛选得到了癸醛等15种最为关键的活性香气物质,并运用主成分分析法(PCA)和聚类分析法(CA)对其活性值进行了分析.由PCA分析得到:性腺样品香气品质较佳,戊醛等8种为表征“高品质风味”的特征性香气物质(其中2,4-庚二烯醛最为重要).由CA分析得到:大闸蟹性腺样品可聚为一类,戊醛等8种活性香气成分也可聚为一类.主成分分析和聚类分析结果存在一致性且可以相互补充,今后可利用两种方法建立大闸蟹香气品质的评价模型.

  16. Ultrastructural observation on virus infection in the gill epithelium of Chinese mitten crab Eriocheir sinensis%中华绒螯蟹腮上皮细胞病毒侵染的超微结构观察

    Institute of Scientific and Technical Information of China (English)

    王文; 陈建秀; 杜开和

    2004-01-01

    我们在研究中华绒螯蟹颤抖病的过程中发现了三种病原微生物,类立克次氏体(rickettsia-like organism RLO)、微孢子虫(nlicrosporidian—like protozoan MLP)和类病毒颗粒(virus-like panicles VLP),并通过病理学、流行病学及人工回感等实验证实RLO为第一致病微生物,MLP和VLP均为二次侵染微生

  17. Status of Chinese horseshoe crab population and conservation advance in Beihai, Guangxi%广西北海中国鲎资源现状以及保育工作进展

    Institute of Scientific and Technical Information of China (English)

    李琼珍; 胡梦红

    2011-01-01

    中国鲎种群数量近年来急剧下降,资源面临枯竭.位于北部湾的广西北海作为中国鲎理想栖息地,是我国中国鲎的主要产地,因此在北海开展中国鲎的保育工作尤为重要.本文调查分析了广西北海地区中国鲎幼体集聚地西背岭潮间带(21°24′30″N-21°25′24″N及109°11′12″E-109°13′14″E)中国鲎幼体分布现状以及该地区的环境特点,为将来在北海地区划出特定区域对中国鲎进行保护,建立其自然保护区,从根本上保护中国鲎资源提供依据.最后介绍了广西北海中国鲎保育工作研究进展,展望了在北海金海湾生态旅游区建立中国鲎自然保护区的前景.%The chinese horseshoe crabs Tachypleus tridentatus are faced with a rapid population decline and local extinction risk. The Beihai of Guangxi Province which locates in Beibu Gulf is one of ideal habitats for the Chinese horseshoe crab,therefore ,it is importnt to adopt the relevant conservation actions for this animal species. The current distribution status of juvenile Chinese horseshoe crab and environmental factors of their habitat were studied in Xibei Ling inter tidal zone of Beihai, Guangxi (21 °24′30"N ~ 21°25′24"N; 109°11′12"E ~ 109°13′14"E) ,in order to provide the necessary references for the Chinese horseshoe crab conservation in Beihai. The research process of the Chinese horseshoe crab conservation in Beihai was summarized, and the perspective of the Chinese horseshoe crab nature reserve construction was also discussed.

  18. Effect of Salinity on Hemolymph Osmotic Pressure, Sodium Concentration and Na+-K+-ATPase Activity of Gill of Chinese Crab, Eriocheir sinensis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of salinity on hemolymph osmotic pressure, Na+ concentration and Na+-K+-ATPase activity of gill of Chinese crab Eriocheir sinensis were studied. The results showed that hemolymph osmotic pressure and Na+ concentration increased significantly (P<0.05), and the Na+-K+-ATPase activity of gills decreased significantly (P<0.05) when salinity increased from 0 to 16. The hemolymph osmotic pressure and Na+ concentration in each treatment group rose remarkably at 0.125 d or 0.25 d, while the Na+-K+-ATPase activity of gill reduced gradually with increased experiment time in 3 d. Then the three parameters remained at a constant level after 0.25 d, 0.125 d and 3 d, respectively, and higher hemolymph osmotic pressure, higher Na+ concentration and lower Na+-K+-ATPase activity of gill occurred at higher salinity. The effect of salinity change on protein concentration of hemolymph was indistinct (P>0.05); However, the protein concentration decreased gradually with the increase of salinity from 0.25 d to 1 d, and then tended to be stable from day 1 to day 15.

  19. 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...

  20. 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.

  1. 盐度对中华绒螯蟹雌性亲蟹代谢的影响%Effect of salinity on the metabolism of female Chinese crabs,Eriocheir sinensis

    Institute of Scientific and Technical Information of China (English)

    庄平; 贾小燕; 冯广朋; 章龙珍; 王瑞芳

    2012-01-01

    We evaluated the effect of salinity on the metabolism of female Chinese crabs (Eriocheir sinensis). The crabs, body weight (55.59 ± 6.24) g, were held at salinities of 0, 6, 12, 18 and 24, (16 ± l)tl, and we measured oxygen consumption, CO2 production, and ammonia-N excretion. Using this data, we calculated the respiratory quotient, oxygen-nitrogen ratio, energy consumption rate, and metabolic substrate ratio. Salinity had a significant effect on the oxygen consumption rate and ammonia-N excretion rate (P0.05). Between salinity 12-24, CO2 production and energy consumption were significantly lower than in the control group. Salinity had no effect on the respiratory quotient and oxygen-nitrogen ratio (P>0.05). Our results suggest that lipids are used preferentially as an energy source. Furthermore, proteins were utilized to a much greater extent than carbohydrates. The proportion of lipids in the metabolic substrate increased as salinity increased. Conversely, the carbohydrate metabolic substrate ratio decreased as salinity increased, whereas the protein metabolic substrate ratio remained constant. At salinity 24, the ratio of protein, carbohydrate, and lipid used as metabolic substrate was 6.4:14.6:79.0. During the reproductive migration, the female Chinese crab migrates from fresh water into the Yangtze River estuary. Thus, individuals must adjust to the higher salinity and modify their energy metabolism. Our results suggest that energy consumption decreases after entering salt water, allowing female crabs to divert energy into reproduction.%测定了不同盐度(0,6,12,18,24)条件下,中华绒螯蟹(Eriocheir sinensis)雌性亲蟹的耗氧率、CO2排出率及NH3-N排泄率,并研究了其呼吸熵、氧氮比、代谢率及能源物质供能比随盐度的变化情况.结果表明,体质量为(55.59±6.24)g的中华绒螯蟹雌性亲蟹,在水温(16±1)℃条件下,盐度对其耗氧率及NH3-N排泄率影响显著(P<0.05).在实验盐度范围内(0~24),

  2. Edible crabs of Kenya

    OpenAIRE

    Muthiga, N.

    1986-01-01

    This is a short paper on the edible crabs of Kenya especially Scylla serrata , their present state of exploitation, distribution, abundance and biology. Preliminary investigations have shown that the crab resources are under-exploited. Research is therefore needed into the available stocks, methods of harvesting, processing, marketing and their biologies.

  3. 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.

  4. Studies of Antimicrobial Peptides Hepcidin and Scygonadin in Chinese Marine-cultured Fishes and Mud Crab%海洋鱼类和青蟹抗菌肽hepcidin和scygonadin的研究

    Institute of Scientific and Technical Information of China (English)

    王克坚

    2011-01-01

    抗菌肽或抗微生物肽因具有杀死或抑制微生物的共同特性,近年来科学家又将这些肽类称为"天然抗生素",有望在将来作为一种新型的生物药物替代现有的化学类抗生素.海洋动物中蕴藏着世界上丰富的抗菌活性物质,研究与开发应用海洋动物抗菌肽成为近年来的研究热点.结合国内外的相关研究进展,简要总结了课题组近年来在我国海水养殖鱼类抗菌肽hepcidin和青蟹抗菌肽scygonadin的研究进展,从抗菌肽的蛋白分离、纯化、基因克隆、基因表达模式、基因工程表达以及抗菌肽合成与表达产品的抗菌活性等进行了简要细致的叙述,对深入探索海洋动物抗菌肽在我国水产养殖业的开发应用具有重要的参考价值.%The small native compounds are isolated from various species of lives,with resistant activity against bacteria , are known as "antibacterial peptides"or "antimicrobial peptides" ( AMPs) and are also thought as "natural antibiotics " in recent years by scientists.It is widely acknowledged that these defensive compounds or AMPs could become new types of bio-antibiotics substituting for the currently used chemical antibiotics in near future. More and more people in the world realize that there are luxuriant AMPs existing in the marine animals , plants and microorganisms. The study of AMPs in marine animals is now the hotspot in research, thus attracting many researchers engaged in this area. The author briefly summarizes some typical results obtained from the study of AMPs in his group in recent several years. His group has done a lot of work in mining of genes and isolation of proteins which are related to antimicrobial activity from Chinese cultured fishes and crabs. More than 20 hepcidin cDNA sequences have been identified and the gene expression patterns were investigated in normal and bacterial challenged fish including Lateolabrax japonicus , Pagrus major , Sparus macrocephlus, Tilapia

  5. The Crab Halo

    Science.gov (United States)

    Lundqvist, Peter

    2011-10-01

    The Crab Nebula, along with its central pulsar and its explosive originin SN 1054, plays a crucial role in our understanding of the linkbetween supernovae and pulsar formation and activity.Yet, there are fundamental uncertainties in the nature of the event thathave not been settled in more than two decades of investigation.The observed mass in the nebula and pulsar is nearly half of theexpected initial stellar mass and the observed energy {much of whichmay come from the central pulsar} is only a fewpercent of the typical supernova energy.An attractive solution to this ``missing mass'' problem is that this massis in a high velocity envelope around the observed Crab Nebula.The envelope would have most of the energy of the explosion {roughly 10^{51} ergs}, bringing the energy up to that typical of a Type II supernova. The fact that the Crab filaments have a measured acceleration and show no deceleration at the outer edge is consistent with this hypothesis. The lack of an interaction region created by the fast shell can be attributed to a very low density around the supernova. We propose to search for the fast shell by taking a COS spectrum of the Crab pulsar in the region of the C IV 1550 line. We have carried out time-dependent ionization calculations that show that this line should produce a detectable broad, blueshifted absorption if the shell is present.

  6. 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...

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. Absolutely Chinese

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>Ink painting animation - an exquisite art form that ends up in a museum Little Tadpole Looking for Mummy Little Tadpole Looking for Mummy, China’s first ink painting animation, was produced in 1961. With innovation in painting, photography and production technology, it was the first effort at ’animating’ ink paintings. Fishes, shrimps, frogs and crabs in the film resemble those in Qi Baishi’s works. By any shot, it’s an animated painting of fishes and insects, one that is suffused with a taste of Chinese ink-and-wash painting.

  13. Crab Compensation for LHC Beams

    CERN Document Server

    Calaga, R; Tomás, R; Zimmermann, F

    2008-01-01

    An R&D program to establish a road map for the installation of crab cavities in the LHC is rapidly advancing. Both local and global crab schemes are under investigation to develop cavities that will be compatible with the LHC optics and meet the aperture requirements. Space and aperture constraints to accommodate a prototype crab cavity in the LHC along with related optics issues are presented. The design of a prototype $TM_{110}$ cavity and pertinent RF requirements including impedance estimates and damping are discussed.

  14. 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...

  15. 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".

  16. 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.

  17. 福建及中国其他沿岸海域中国鲎资源分布现状调查%Distribution and Resource of Chinese Horseshoe Crab ( Tachypleus tridentatus ) in Fujian and Other Coast Water of China

    Institute of Scientific and Technical Information of China (English)

    翁朝红; 谢仰杰; 肖志群; 黄良敏; 李军; 王淑红; 张雅芝

    2012-01-01

    By interviewing local fishermen, we collected population status information of Horseshoe Crab (Tachypleus tiidentatus) in the coasts of Zhejiang, Fujian, Guangxi, Guangdong and Hainan in the summer from 2006 to 2010 and we also visited 27 hatching sites in those coasts to survey the number of spawning adults and baby Horseshoe Crab hatched. We estimated the current resource of this species in Fujian by sampling them at 24 locations twice using shallow bottom trawling in summer 2006 and winter 2007, the results showed that local fishermen found out the population size of this species decrease greatly in most coasts of Zhejiang, Fujian, Guangxi, Guangdong and Hainan. No any spawning adults have been observed in the 27 hatching sites and few juveniles were found in 6 of the 27 sites. Fortunately at one more site ( Zhangpugulei Fujian Province) we counted over 1 000 juveniles. The horseshoe crab almost disappears and is at the edge of extinction in most coast of China except for Dongshan Bay and Beibu Bay where a few Horseshoe Crabs have survived. However, the resource of Horseshoe Crab in the Coast of Kinmen Island of Taiwan has been recovered well due to artificial breeding and releasing, as well as the establishment of protected areas. The decline of Horseshoe Crab resource in China is mainly due to over-harvest, habitat destruction and marine environment pollution. This species is urgent to be protected. We suggest to include it in national key protection animals list, establish nature reserves at their hatching habitat, strengthen harvest regulation and conduct artificial propagation to protect this species.%采用调访渔民、浅海底拖网、野外观测潮间带亲鲎产卵和幼鲎孵育情况等调查方法,重点调查了福建沿岸海域中国鲎(Tachypleus tridentatus)资源分布和数量,并走访调查了浙江省、广东省、海南省、广西壮族自治区和台湾地区金门岛等地代表性的中国鲎栖息地,对中国沿岸海域中国

  18. Bare fingers, but no obvious influence of "prickly" Velcro! In the absence of parents' encouragement, it is not clear that "sticky mittens" provide an advantage to the process of learning to reach.

    Science.gov (United States)

    Corbetta, Daniela; Williams, Joshua L; Haynes, Jeremy M

    2016-02-01

    In their critique of our mittens study, Needham et al. (2015. Infant Behavior and Development) describe our findings as "surprising." Further; they suggest that babies in our "sticky mittens" condition may have been discouraged from reaching because, in our study, infants may have touched "prickly" Velcro with their bare fingers. In this response, we present data analyses that do not support the interpretation that finger contact with our Velcroed toy surfaces was associated with poor reaching performance in our "sticky" mittens group. We also clarify that our toys were mainly covered with "non-prickly" Velcro. To explain discrepancies between studies, we restate the original intent of our study and reasons for our methodological modifications. We point to confounds and lack of critical control conditions in the Needham et al. studies, which prevent the making of firm inferences about the effectiveness of the "sticky mittens experience" on the learning to reach process. We also present additional analyses on our "sticky" mittens group showing that the increasing rate of finger touch on the toy leads to greater reaching performance while the rate of toy sticking to the mittens does not. We discuss the importance of sensory-motor experience on the development of learning to reach in infancy and conclude that our results are not surprising.

  19. 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...

  20. 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.

  1. 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.

  2. Space Movie Reveals Shocking Secrets Of The Crab Pulsa

    Science.gov (United States)

    2002-09-01

    Just when it seemed like the summer movie season had ended, two of NASA's Great Observatories have produced their own action movie. Multiple observations made over several months with NASA's Chandra X-ray Observatory and the Hubble Space Telescope captured the spectacle of matter and antimatter propelled to near the speed of light by the Crab pulsar, a rapidly rotating neutron star the size of Manhattan. "Through this movie, the Crab Nebula has come to life," said Jeff Hester of Arizona State University in Tempe, lead author of a paper in the September 20th issue of The Astrophysical Journal Letters. "We can see how this awesome cosmic generator actually works." The Crab was first observed by Chinese astronomers in 1054 A.D. and has since become one of the most studied objects in the sky. By combining the power of both Chandra and Hubble, the movie reveals features never seen in still images. By understanding the Crab, astronomers hope to unlock the secrets of how similar objects across the universe are powered. Crab Nebula Composite Image Crab Nebula Composite Image Bright wisps can be seen moving outward at half the speed of light to form an expanding ring that is visible in both X-ray and optical images. These wisps appear to originate from a shock wave that shows up as an inner X-ray ring. This ring consists of about two dozen knots that form, brighten and fade, jitter around, and occasionally undergo outbursts that give rise to expanding clouds of particles, but remain in roughly the same location. "These data leave little doubt that the inner X-ray ring is the location of the shock wave that turns the high-speed wind from the pulsar into extremely energetic particles," said Koji Mori of Penn State University in University Park, a coauthor of the paper. Another dramatic feature of the movie is a turbulent jet that lies perpendicular to the inner and outer rings. Violent internal motions are obvious, as is a slow motion outward into the surrounding nebula of

  3. 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.

  4. 50 CFR Table 2 to Part 680 - Crab Species Code

    Science.gov (United States)

    2010-10-01

    ..., Table 2 Table 2 to Part 680—Crab Species Code Species code Common name Scientific name 900 Box... crab Paralithodes platypus. 923 Golden (brown) king crab Lithodes aequispinus. 924 Scarlet king...

  5. 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...

  6. LHC crab cavity final report

    CERN Document Server

    Burt, G et al

    2013-01-01

    A compact 400 MHz SRF crab cavity is designed for LHC. The design has low surface fields, has no hard multipactor barriers and fits within the transverse space available on the HL-LHC. The structure has been designed to have a constant deflecting voltage across the beam-pipe aperture and this has been verified on an aluminium model. The structure includes designs for the input and lower order mode couplers.

  7. 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.

  8. 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...

  9. 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.

  10. 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...

  11. a Surprise from the Pulsar in the Crab Nebula

    Science.gov (United States)

    1995-11-01

    at optical wavelengths and only one is bright enough to allow reasonably detailed spectroscopic observations with currently available optical telescopes. The Crab Pulsar This is the famous Crab Pulsar, also known as PSR 0531+21. It was discovered as a radio pulsar in 1968, soon after the detection of the first known radio pulsar. A little later, pulsed optical emission from the Crab Pulsar was also observed. It was quickly recognized that this emission obeys Pacini's law [2]. Stated in simple terms, this implies that the emission of optical light from the pulsar is due to the interaction between very energetic elementary particles close to the neutron star and its incredibly strong magnetic field. The Crab Pulsar is especially interesting, because we have detailed historical information about the event from which it was born: the very bright `guest star' which was so well observed and described by Chinese astronomers in the year 1054 AD in the constellation of Taurus (the Bull). At the exact location of this supernova is now observed the famous Crab Nebula in which the Crab Pulsar is embedded. The Crab Nebula is a very conspicuous object in the sky (the name alludes to its overall form), and it emits a very significant amount of energy at all wavelengths of the electromagnetic spectrum that have so far been explored, from long-wave radio waves to gamma-rays of ultra-high energy. At X-ray wavelengths (above 1 keV), it is in fact one of the brightest, continuously emitting sources in the sky. The Crab Pulsar also emits at all wavelengths, but it is much fainter than the surrounding nebula. This Press Release is accompanied by a photo with caption, showing the pulsar in the innermost region of the nebula. At optical wavelengths, the Crab Pulsar is a comparatively faint, point-like object of magnitude 16.6. It is interesting to note that, from the measured, outward motion of the individual condensations in the Crab Nebula, this object was recognized, already a decade

  12. 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.

  13. 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.

  14. Diversity, endemism and conservation of the freshwater crabs of China (Brachyura: Potamidae and Gecarcinucidae).

    Science.gov (United States)

    Cumberlidge, Neil; Ng, Peter K L; Yeo, Darren C J; Naruse, Tohru; Meyer, Kirstin S; Esser, Lara J

    2011-03-01

    China lies at the heart of the global center of freshwater crab diversity in tropical Asia, where the 2 most diverse families occur: Potamidae (505 species, 95 genera) and Gecarcinucidae (344 species, 59 genera). China stands out as the country with the highest species richness of freshwater crabs globally. Its fauna comprises 243 species in 37 genera and in 2 families, and species discovery is still progressing at a rapid pace. The vast majority of the species are distributed in southwest, south central and eastern China in the Oriental zoogeographical region. China also stands out as having a highly endemic freshwater crab fauna at the species level (96%) and at the genus level (78%). Although the recent International Union for the Conservation of Nature (IUCN) red list conservation assessment found only 6 out of 228 species (2%) to be threatened (5 potamids and 1 gecarcinucid), the majority (more than 75%) of Chinese species are regarded as data deficient, so the number of threatened species is likely to be a serious underestimate. Threats from increasing habitat destruction and pollution are a major concern due to the rapidly growing economy and massive developments taking place in China. There is therefore an urgent need for increased species exploration and for the development of a conservation strategy for China's threatened (and potentially threatened) endemic freshwater crab species.

  15. 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

  16. 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...

  17. 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.

  18. Wakefield damping for the CLIC crab cavity

    CERN Document Server

    Ambattu, P K; Dexter, A C; Carter, R G; Khan, V; Jones, R M; Dolgashev, V

    2009-01-01

    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.

  19. WAKEFIELD DAMPING FOR THE CLIC CRAB CAVITY

    CERN Document Server

    Ambattu, P; Dexter, A; Carter, R; Khan, V; Jones, R; Dolgashev, V

    2009-01-01

    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.

  20. 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

  1. 50 CFR Table 2b to Part 679 - Species Codes: FMP Prohibited Species and CR Crab

    Science.gov (United States)

    2010-10-01

    ... CR Crab 2b Table 2b to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... CR Crab Species Description Code CR Crab Groundfish PSC CRAB Box Lopholithodes mandtii 900... ✓ Korean horsehair crab Erimacrus isenbeckii 940 ✓ Multispinus crab Paralomis multispinus 951 ✓...

  2. LHC Crab Cavity Progress and Outlook

    CERN Document Server

    Calaga, R

    2013-01-01

    Three novel superconducting RF crab cavity designs proposed for the LHC luminosity upgrade have rapidly progressed. First Niobium prototypes are reaching close to the design performance and beyond. The highlights of the RF test results from the prototypes along with design modifications for initial beam tests in the SPS are presented. The status of the cryomodule development, integration into the SPS and the beam tests in view of validating the crab cavity system for LHC upgrade are addressed.

  3. 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...

  4. Crab-crossing in a Tau-Charm facility

    International Nuclear Information System (INIS)

    This report discusses the following topics: crab-crossing; horizontal versus vertical beam crossing; a crab-crossing arrangement for a Tau-Charm facility; tolerance; and beam loading and average current limitations. 7 refs., 1 fig., 1 tab

  5. 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...

  6. Chemoreception in the blue crab, Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-10-01

    The aims of the study were to observe the feeding behavior of the blue crab under laboratory conditions and select those components of the feeding repertoire that appeared to be most sensitive to the presence of sapid substances, utilize the selected behavioral components to determine the threshold concentration at which a food extract is detected, and examine the effects of food deprivation upon the detection threshold. Results showed that: (1) An increase in the rate of antennule flicking and gill bailing upon presentation of sea water solutions of a freeze-dried clam extract indicated detection of sapid substances by the blue crab, Callinectes sapidus. (2) The threshold concentration at which crabs detected the sapid solution was 10 (E-15) g/liter. Feeding behaviors were released at higher concentrations, 10 (E-1) to 10 (E-2) g/liter. (3) Food deprivation for six days lowered the threshold for feeding behaviors but did not affect the detection threshold.

  7. 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.

  8. 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.

  9. An assessment of discard mortality for two Alaskan crab species, Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio), based on reflex impairment

    OpenAIRE

    Stoner, Allan W.; Rose, Craig S.; Munk, J. Eric; Hammond, Carwyn F.; Davis, Michael W.

    2008-01-01

    Delayed mortality associated with discarded crabs and fishes has ordinarily been observed through tag and recovery studies or during prolonged holding in deck tanks, and there is need for a more efficient assessment method. Chionoecetes bairdi (Tanner crab) and C. opilio (snow crab) collected with bottom trawls in Bering Sea waters off Alaska were evaluated for reflexes and injuries and held onboard to track mortality. Presence or absence of six reflex actions was determined and combine...

  10. 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

  11. 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.

  12. A HYPERSPECTRAL VIEW OF THE CRAB NEBULA

    International Nuclear Information System (INIS)

    We have obtained spatially resolved spectra of the Crab nebula in the spectral ranges 450-520 nm and 650-680 nm, encompassing the Hβ, [O III] λ4959, λ5007, Hα, [N II] λ6548, λ6584, and [S II] λ6717, λ6731 emission lines, with the imaging Fourier transform spectrometer SpIOMM at the Observatoire du Mont-Megantic's 1.6 m telescope. We first compare our data with published observations obtained either from a Fabry-Perot interferometer or from a long-slit spectrograph. Using a spectral deconvolution technique similar to the one developed by Cadez et al., we identify and resolve multiple emission lines separated by large Doppler shifts and contained within the rapidly expanding filamentary structure of the Crab. This allows us to measure important line ratios, such as [N II]/Hα, [S II]/Hα, and [S II] λ6717 /[S II] λ6731 of individual filaments, providing a new insight on the SE-NW asymmetry in the Crab. From our analysis of the spatial distribution of the electronic density and of the respective shocked versus photoionized gas components, we deduce that the skin-less NW region must have evolved faster than the rest of the nebula. Assuming a very simple expansion model for the ejecta material, our data provide us with a complete tridimensional view of the Crab.

  13. 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.

  14. 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.

  15. Tarantula and Hermit Crab Emergency Care.

    Science.gov (United States)

    Marnell, Cinthia

    2016-05-01

    Tarantulas and hermit crabs are commonly kept pets and are underappreciated in veterinary medicine. Safe handling, biology and husbandry, diagnostic techniques, anesthesia, fluid therapy, disorders, and euthanasia are covered in this article. Current research is applied to these topics to keep practitioners abreast with the best medicine for these creatures. PMID:27131164

  16. How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

    Science.gov (United States)

    Onken, H.; Graszynski, K.; Johannsen, A.; Putzenlechner, M.; Riestenpatt, S.; Schirmer, C.; Siebers, D.; Zeiske, W.

    1995-03-01

    In the present article we review our findings on split lamella preparations of crab gills mounted in modified Ussing-chambers with respect to mechanistic and ecophysiological aspects. The leaky gill epithelium of shore crabs adapted to brackish water absorbs Na+ and Cl- in a coupled mode, and shows similarities to other salt-absorbing epithelia exposed to moderately diluted media. The results so far obtained for NaCl uptake across the gills of the shore crab are compatible with a transport model where two cell types operate in parallel, one displaying cotransport-like NaCl absorption, similar to that in the thick ascending limb of Henle's loop of the mammalian mephron, and the other one with characteristics of amiloride-sensitive, channel-mediated Na+ uptake by frog skin. Although there is no clear evidence for the apical mechanisms in this model, it may serve as a good basis for more detailed studies in the future. The moderately tight gill epithelium of freshwater adapted Chinese crabs absorbs Na+ and Cl- independently from each other, and shows similarities to other salt-absorbing epithelia exposed to freshwater. The characteristics of a positive, Na+-dependent short-circuit current with externally Cl--free saline indicate that active Na+ uptake proceeds in a frog-skin-like mode via apical Na+-channels and the basolateral Na+/K+-pump. The nature of a negative short-circuit current with external Cl--saline indicates that active and Na+-independent Cl- uptake is driven by an apical V-type H+-pump and proceeds via apical Cl-/ HCO3 --exchange and basolateral Cl--channels.

  17. 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.

  18. Ghost fishing activity in derelict blue crab traps in Louisiana.

    Science.gov (United States)

    Anderson, Julie A; Alford, Amy B

    2014-02-15

    Derelict crab traps impact the coastal ecosystem through continued catch of target species and species of conservation, economic, or recreational importance. During volunteer-supported crab trap cleanups in 2012 and 2013, we quantified ghost fishing activity in derelict crab traps in coastal Louisiana through a citizen scientist program. Volunteers removed 3607 derelict traps during these events, and over 65% of traps analyzed by citizen scientists were actively ghost fishing. Additionally, volunteers identified 19 species enmeshed in derelict traps, including a combination of fresh and saltwater species. We also detected a significant difference in the number of blue crab in actively ghost fishing derelict traps across removal locations with estimated catches varying between 2.4 and 3.5 crabs/trap. Our instantaneous estimates of ghost fishing activity are greater than those previously thought in Louisiana, further justifying current derelict crab trap prevention and removal extension and outreach programs in Louisiana and throughout the Gulf of Mexico. PMID:24360333

  19. Reproduction in crabs: strategies, invasiveness and environmental influences thereon

    OpenAIRE

    Brink, van den, R.B.A.

    2013-01-01

    This thesis provides insights into the interconnectedness of crab reproductive biology, the selective forces leading to their development, the possible links to invasiveness and the influences of environmental factors thereon. The empirical data collected and presented in this thesis can be used to compare different crab species and make predictions about the effect of climate change on their population dynamics and invasiveness. Two crab species in particular are examined in this thesis, Hal...

  20. Compensation of the Crossing Angle with Crab Cavities at KEKB

    CERN Document Server

    Abe, T; Akemoto, M; Akiyama, A; Arinaga, M; Ebihara, K; Egawa, K; Enomoto, A; Flanagan, J; Fukuda, S; Fukuma, H; Funakoshi, Y; Furukawa, K; Furuya, T; Hara, K; Higo, T; Hiramatsu, S; Hisamatsu, H; Honma, H; Honma, T; Hosoyama, K; Ieiri, T; Iida, N; Ikeda, H; Ikeda, M; Inagaki, S; Isagawa, S; Ishii, H; Kabe, A; Kadokura, E; Kageyama, T; Kakihara, K; Kako, E; Kamada, S; Kamitani, T; Kanazawa, K; Katagiri, H; Kato, S; Kawamoto, T; Kazakov, S; Kikuchi, M; Kikutani, E; Kitagawa, K; Koiso, H; Kojima, Y; Komada, I; Kubo, T; Kudo, K; Kudo, N; Marutsuka, K; Masuzawa, M; Matsumoto, S; Matsumoto, T; Michizono, S; Mikawa, K; Mimashi, T; Mitsunobu, S; Mori, K; Morita, A; Morita, Y; Nakai, H; Nakajima, H; Nakamura, T T; Nakanishi, H; Nakanishi, K; Nakao, K; Ninomiya, S; Ogawa, Y; Ohmi, K; Ohsawa, S; Ohsawa, Y; Ohnishi, Y; Ohuchi, N; Oide, K; Ono, M; Ozaki, T; Saitô, K; Sakai, H; Sakamoto, Y; Sato, M; Satoh, M; Shibata, K; Shidara, T; Shirai, M; Shirakawa, A; Sueno, T; Suetake, M; Suetsugu, Y; Sugahara, R; Sugimura, T; Suwada, T; Tajima, O; Takano, S; Takasaki, S; Takenaka, T; Takeuchi, Y; Tawada, M; Tejima, M; Tobiyama, M; Tokuda, N; Uehara, S; Uno, S; Yamamoto, Y; Yano, Y; Yokoyama, K; Yoshida, Ma; Yoshida, Mi; Yoshimoto, S; Yoshino, K; Perevedentsev, E; Shatilov, D N

    2007-01-01

    Crab cavities have been installed in the KEKB B--Factory rings to compensate the crossing angle at the collision point and thus increase luminosity. The beam operation with crab crossing has been done since February 2007. This is the first experience with such cavities in colliders or storage rings. The crab cavities have been working without serious issues. While higher specific luminosity than the geometrical gain has been achieved, further study is necessary and under way to reach the prediction of simulation.

  1. 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.

  2. 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.

  3. Crab Crossing Schemes and Studies for Electron Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    S. Ahmed, Y. Derbenev, V. Morozov, A. Castilla, G.A. Krafft, B. Yunn, Y. Zhang, J.R. Delayen

    2011-09-01

    This report shows our progress in crab crossing consideration for future electron-ion collider envisioned at JLab. In this design phase, we are evaluating two crabbing schemes viz., the deflecting and dispersive. The mathematical formulations and lattice design for these schemes are discussed in this paper. Numerical simulations involving particle tracking through a realistic deflecting RF cavity and optics illustrate the desired crab tilt of 25 mrad for 1.35 MV. Evolution of beam propagation are shown which provides the physical insight of the crabbing phenomenon.

  4. A search for shells around crabs

    International Nuclear Information System (INIS)

    Prior to conducting a survey of the galactic plane at 327 MHz using the VLA, the authors have imaged four fields near galactic longitude of 20 degrees. Each image will cover a 2.5 degree field with ∼ 1 arcmin resolution. The fields have been chosen to include the remnants G20.0-0.2, G21.5-0.9, and G24.7 + 0.6. The first two are isolated Crab-like objects, that is, there is no discernible associated shell. Since such shells have relatively steep spectra, images at 327 MHz will be more sensitive to their presence. The absence of a shell can constrain the density of the ISM in the vicinity of the SNR. Since ∼ 50% of Crabs are naked, the implications can be extended to a significant fraction of the ISM

  5. 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.

  6. Element Distributions In The Crab Nebula

    OpenAIRE

    Satterfield, T. J.; Katz, A. M.; Sibley, A. R.; G. M. MacAlpine; Uomoto, A.

    2012-01-01

    Images of the Crab Nebula have been obtained through custom interference filters which transmit emission from the expanding supernova remnant in HI, HeI, HeII, [CI], [NII], [OI], [SII], and [SIII] emission lines. We present both raw and flux-calibrated data. Arrays of 19,440 photoionization models, with extensive input abundance ranges, were matched pixel by pixel to the calibrated data in order to derive corresponding element abundance or mass-fraction distributions for helium, carbon, nitro...

  7. Status of the ILC Crab Cavity Development

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Cockcroft Inst. Accel. Sci. Tech.; Beard, C.; Goudket, P.; McIntosh, P.; /Daresbury; Bellantoni, L.; /Fermilab; Grimm, T.; Li, Z.; Xiao, L.; /SLAC

    2011-10-20

    The International Linear Collider (ILC) will require two dipole cavities to 'crab' the electron and positron bunches prior to their collision. It is proposed to use two 9 cell SCRF dipole cavities operating at a frequency of 3.9 GHz, with a transverse gradient of 3.8MV/m in order to provide the required transverse kick. Extensive numerical modelling of this cavity and its couplers has been performed. Aluminium prototypes have been manufactured and tested to measure the RF properties of the cavity and couplers. In addition single cell niobium prototypes have been manufactured and tested in a vertical cryostat. The International Collider (ILC) [1] collides bunches of electrons and positrons at a crossing angle of 14 mrad. The angle between these bunches causes a loss in luminosity due to geometric effects [2]. The luminosity lost from this geometric effect can be recovered by rotating the bunches into alignment prior to collision. One possible method of rotating the bunches is to use a crab cavity [3]. A crab cavity is a transverse defecting cavity, where the phase of the cavity is such that the head and tail of the bunch receive equal and opposite kicks. As the bunches are only 500 nm wide in the horizontal plane, the cavity phase must be strictly controlled to avoid the bunch centre being deflected too much. In order to keep the phase stability within the required limits it is required that the cavity be superconducting to avoid thermal effects in both the cavity and its RF source. At the location of the crab cavity in the ILC there is only 23 cm separation between the centre of the cavity and the extraction line, hence the cavity must be small enough to fit in this space. This, along with the difficulty of making high frequency SRF components, set the frequency of the cavity to 3.9 GHz.

  8. The Crab Nebula's Moving Wisps in Radio

    CERN Document Server

    Bietenholz, M F; Hester, J J

    2001-01-01

    We present three high resolution radio images of the Crab nebula, taken in 1998.6, 1998.8 and 2000.1 with the VLA. These are the best radio images of the Crab to date. We show that, near the pulsar, there are significant changes between our three observing epochs. These changes have an elliptical geometry very similar to that of the optical wisps. One radio wisp in particular can be unambiguously identified between two of our observing epochs, and moves outward with an apparent velocity of ~0.24. The similarity in both morphology and behavior of the present radio wisps to the optical wisps suggests that they are associated. This implies that the radio wisps, like the optical ones, are likely manifestations of the shock in the Crab pulsar's wind. This suggests that the radio emitting electrons are accelerated in the same region as the ones responsible for the optical to X-ray emission, contrary to most current models.

  9. CMS distributed data analysis with CRAB3

    Science.gov (United States)

    Mascheroni, M.; Balcas, J.; Belforte, S.; Bockelman, B. P.; Hernandez, J. M.; Ciangottini, D.; Konstantinov, P. B.; Silva, J. M. D.; Ali, M. A. B. M.; Melo, A. M.; Riahi, H.; Tanasijczuk, A. J.; Yusli, M. N. B.; Wolf, M.; Woodard, A. E.; Vaandering, E.

    2015-12-01

    The CMS Remote Analysis Builder (CRAB) is a distributed workflow management tool which facilitates analysis tasks by isolating users from the technical details of the Grid infrastructure. Throughout LHC Run 1, CRAB has been successfully employed by an average of 350 distinct users each week executing about 200,000 jobs per day. CRAB has been significantly upgraded in order to face the new challenges posed by LHC Run 2. Components of the new system include 1) a lightweight client, 2) a central primary server which communicates with the clients through a REST interface, 3) secondary servers which manage user analysis tasks and submit jobs to the CMS resource provisioning system, and 4) a central service to asynchronously move user data from temporary storage in the execution site to the desired storage location. The new system improves the robustness, scalability and sustainability of the service. Here we provide an overview of the new system, operation, and user support, report on its current status, and identify lessons learned from the commissioning phase and production roll-out.

  10. 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

  11. 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.

  12. 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. PMID:27441254

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. SMALL ANGLE CRAB COMPENSATION FOR LHC IR UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    CALAGA,R.; DORDA, U.; OHMI, D.; OIDE, K.; TOMAS, R.; ZIMMERMANN, F.

    2007-06-25

    A small angle (< 1 mrad) crab scheme is an attractive option for the LHC luminosity upgrade to recover the geometric luminosity loss from the finite crossing angle [I]. The luminosity loss increases steeply to unacceptable levels as the IP beta function is reduced below its nominal value (see Fig. 1 in Ref. [2]). The crab compensation in the LHC can be accomplished using only two sets of deflecting RF cavities, placed in collision-free straight sections of the LHC to nullify the effective crossing angles at IPI & IP5. We also explore a 400 MHz superconducting cavity design and discuss the pertinent RF challenges. We present IR optics configurations with low-angle crab crossing, study the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, lattice errors, and crab RF noise sources.

  19. 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)

  20. 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.

  1. 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...

  2. 50 CFR 648.263 - Red crab possession and landing restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Red crab possession and landing... Management Measures for the Atlantic Deep-Sea Red Crab Fishery § 648.263 Red crab possession and landing restrictions. (a) Vessels issued limited access red crab permits—(1) Possession and landing restrictions. (i)...

  3. 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.

  4. 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.

  5. 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.

  6. Effects of pesticides on crab cheliped regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Costlow, J.D. Jr.

    1993-01-01

    The mud crab cheliped regeneration bioassay has proven to be a sensitive and reliable bioassay in studies of the potential sublethal effects of pesticides, including teratogenesis, spontaneous autotomy, and duration of the various stages of development. The assay has also been demonstated to be a useful indication of mortality associated with the impact of these chemicals of anthropogenic origin during the megalopal and early postlarval stages of development. Four pesticides were tested here using the cheliped regeneration bioassay technique. Although carbofuran is approximately 5--6 times more toxic than methomyl, both compounds yield very similar results in terms of sublethal effects.

  7. 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

  8. 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.

  9. 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...

  10. M10.3.4: CLIC crab cavity specifications completed

    CERN Document Server

    Dexter, A; Ambattu, P; Shinton, I; Jones, R

    2010-01-01

    The starting point of Sub-task 2 is to document the currently anticipated requirements for the CLIC crab cavity system. This milestone concerns completion of the basic specifications for the CLIC crab cavity system. This comprises kick, power requirement, phase and amplitude stability, technology choice, and RF layout. The wakefield calculations of a baseline CLIC cavity will be used to estimate the required damping of the higher order modes as well as other special modes in crab cavities (the lower and same order modes).

  11. CLIC CRAB CAVITY SPECIFICATIONS MILESTONE: M10.3.4

    CERN Document Server

    Ambattu, P; Dexter, A; Jones, R; McIntosh, P; Shinton, I

    2010-01-01

    The starting point of Sub-task 2 is to document the currently anticipated requirements for the CLIC crab cavity system. This milestone concerns completion of the basic specifications for the CLIC crab cavity system. This comprises kick, power requirement, phase and amplitude stability, technology choice, and RF layout. The wakefield calculations of a baseline CLIC cavity will be used to estimate the required damping of the higher order modes as well as other special modes in crab cavities (the lower and same order modes).

  12. Effects of Underwater Turbine Noise on Crab Larval Metamorphosis.

    Science.gov (United States)

    Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

    2016-01-01

    The development of marine tidal turbines has advanced at a rapid rate over the last decade but with little detailed understanding of the potential noise impacts on invertebrates. Previous research has shown that underwater reef noise plays an important role in mediating metamorphosis in many larval crabs and fishes. New research suggests that underwater estuarine noise may also mediate metamorphosis in estuarine crab larvae and that the noise emitted from underwater tidal and sea-based wind turbines may significantly influence larval metamorphosis in estuarine crabs. PMID:26611041

  13. Comparison of flavour qualities of three sourced Eriocheir sinensis.

    Science.gov (United States)

    Wang, Shuai; He, Yu; Wang, Yayue; Tao, Ningping; Wu, Xugan; Wang, Xichang; Qiu, Weiqiang; Ma, Mingjun

    2016-06-01

    Flavour qualities of three edible parts of three types of Chinese mitten crab from different areas were examined. The flavour profiles detected by E-tongue and E-nose showed that differences existed in tastes and odours among wild-caught crabs (WC), Yangcheng crabs (YC) and Chongming crabs (CM). The total free amino acids contents of WC were all at the highest level in meat, gonads and hepatopancreas. Ovaries had the highest nucleotides content and equivalent umami concentration (EUC) than other tissues in both female and male. The EUC was the highest in all parts of WC, followed by YC and CM. The total content of nine key volatile compounds was the highest for WC in the gonads and hepatopancreas; in the muscle, they were the highest in female YC and male CM, but the lowest for WC. PMID:26830556

  14. Genome sequencing and comparison of two nonhuman primate animal models, the cynomolgus and Chinese rhesus macaques

    DEFF Research Database (Denmark)

    Yan, Guangmei; Zhang, Guojie; Fang, Xiaodong;

    2011-01-01

    The nonhuman primates most commonly used in medical research are from the genus Macaca. To better understand the genetic differences between these animal models, we present high-quality draft genome sequences from two macaque species, the cynomolgus/crab-eating macaque and the Chinese rhesus...

  15. 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...

  16. 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.

  17. 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).

  18. 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...

  19. 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...

  20. 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...

  1. Crab Orchard Wilderness Character Monitoring Back-end Database

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Back-end data file for the Crab Orchard Wilderness Character Monitoring Application. User interface and lookup databases are required for use.The Wilderness Act of...

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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).

  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 : 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. CLIC Crab Cavity Design Optimisation for Maximum Luminosity

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-25

    The bunch size and crossing angle planned for CERN's compact linear collider CLIC dictate that crab cavities on opposing linacs will be needed to rotate bunches of particles into alignment at the interaction point if the desired luminosity is to be achieved. Wakefield effects, RF phase errors between crab cavities on opposing linacs and unpredictable beam loading can each act to reduce luminosity below that anticipated for bunches colliding in perfect alignment. Unlike acceleration cavities, which are normally optimised for gradient, crab cavities must be optimised primarily for luminosity. Accepting the crab cavity technology choice of a 12 GHz, normal conducting, travelling wave structure as explained in the text, this paper develops an analytical approach to optimise cell number and iris diameter.

  5. CLIC crab cavity design optimisation for maximum luminosity

    Energy Technology Data Exchange (ETDEWEB)

    Dexter, A.C., E-mail: a.dexter@lancaster.ac.uk [Lancaster University, Lancaster, LA1 4YR (United Kingdom); Cockcroft Institute, Daresbury, Warrington, WA4 4AD (United Kingdom); Burt, G.; Ambattu, P.K. [Lancaster University, Lancaster, LA1 4YR (United Kingdom); Cockcroft Institute, Daresbury, Warrington, WA4 4AD (United Kingdom); Dolgashev, V. [SLAC, Menlo Park, CA 94025 (United States); Jones, R. [University of Manchester, Manchester, M13 9PL (United Kingdom)

    2011-11-21

    The bunch size and crossing angle planned for CERN's compact linear collider CLIC dictate that crab cavities on opposing linacs will be needed to rotate bunches of particles into alignment at the interaction point if the desired luminosity is to be achieved. Wakefield effects, RF phase errors between crab cavities on opposing linacs and unpredictable beam loading can each act to reduce luminosity below that anticipated for bunches colliding in perfect alignment. Unlike acceleration cavities, which are normally optimised for gradient, crab cavities must be optimised primarily for luminosity. Accepting the crab cavity technology choice of a 12 GHz, normal conducting, travelling wave structure as explained in the text, this paper develops an analytical approach to optimise cell number and iris diameter.

  6. 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...

  7. Narrative report - Fiscal year 1975 [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 1975 fiscal year. The report begins by summarizing...

  8. 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...

  9. 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...

  10. Monitoring downstream migrations of Eriocheir sinensis H. Milne Edwards, 1853 (Crustacea: Brachyura: Grapsoidea: Varunidae in the River Thames using capture data from a water abstraction intake

    Directory of Open Access Journals (Sweden)

    David Morritt

    2013-06-01

    Full Text Available The International Union for Conservation of Nature has cited Eriocheir sinensis as one of the world’s worst 100 invasive species. Outsidetheir native range, this alien species has had adverse impacts, both ecologically and economically, on river catchments. Understanding thelife cycle of the Chinese mitten crab, especially details of the migration period, is important for the potential control of this exotic species.The mitten crab has been reported from the River Thames, London, England and in this watershed the population continues to increase innumbers, disperse in a westerly direction and reports of a downstream migration date back to 1996. Recently, regular collections from arubbish screen at a River Thames water abstraction point were used to monitor the migration of adult crabs over three years (2008–2010.Details of size, sex and condition of the crabs were recorded as were data on the abstracted flow. The main migration period runs fromAugust to early November with peak numbers of crabs recorded in September/early October. In all years the sex ratio of captured crabs washeavily skewed towards males, which were significantly larger than females. Furthermore there is some evidence that female crabs movelater in the migration period than males and that peaks in numbers of both male and female crabs are associated with full moon periods; peaknumbers demonstrating significant lunar periodicity. In addition there is a weak association between crab numbers and abstraction flow rate.The key findings are used to recommend the timing of any future control measures that might be designed to reduce the population of thisinvasive species in the River Thames. These recommendations could also be applied to other river catchments where the species isproblematic.

  11. Element Distributions In The Crab Nebula

    CERN Document Server

    Satterfield, T J; Sibley, A R; MacAlpine, G M; Uomoto, A

    2012-01-01

    Images of the Crab Nebula have been obtained through custom interference filters which transmit emission from the expanding supernova remnant in HI, HeI, HeII, [CI], [NII], [OI], [SII], and [SIII] emission lines. We present both raw and flux-calibrated data. Arrays of 19,440 photoionization models, with extensive input abundance ranges, were matched pixel by pixel to the calibrated data in order to derive corresponding element abundance or mass-fraction distributions for helium, carbon, nitrogen, oxygen, and sulfur. These maps show distinctive structure, and they illustrate regions of gas in which various stages of nucleosynthesis have apparently occurred, including the CNO-cycle, helium-burning, carbon-burning, and oxygen-burning. It is hoped that the calibrated observations and chemical abundance distribution maps will be useful for developing a better understanding of the precursor star evolution and the supernova explosive process.

  12. 阳澄湖养蟹网围内外轮虫群落结构的变化及分析%The variation and analysis of rotifer community structure in and out of crab-net-pen closing in the Yangcheng Lake

    Institute of Scientific and Technical Information of China (English)

    陈立婧; 刘樵; 彭自然; 胡忠军; 薛俊增; 王武

    2011-01-01

    Rotifer species are cosmopolitan and the endemism is very low. They are highly susceptible to physical and chemical changes in their environment due to their small size and permeable integument, and they are known to be an important link between the microbial loop and higher trophic levels, so rotifer is an excellent indicator of the water status of a lake. Yangcheng Lake is one of the most important freshwater lakes in China. The total area of the lake is 119.04 km2,aquatic plants are dense providing a food source for crabs and the lake yields high numbers of the Chinese mitten crab(Eriocheir sinensis). Currently, although the ecological effects of the pen culture on the environment have received extensive attention,expert mainly focus on aquatic plants, physical and chemical factors, environmental effects and benthic animals, but rarely reported on the rotifer community structures. To date, no studies have been done on rotifers in Yangcheng Lake in detail. Thus, the aim of this study was to analyze the spatial and temporal variation of rotifer community structure and species diversity in net-pen closing and lake areas, in order to provide the data and theoretical basis for aquatic ecosystem of Yangcheng Lake, biodiversity conservation and sustainable development of ecological-pen-culture. Rotifer community structure and several feature parameters of water quality were investigated in 3 controlled sites in net-pen closing and lake areas of Yangcheng Lake, during June 2008 to May 2009. The relationship of rotifer community structure and environmental parameters was analyzed, various parameters were used to assess the water quality. The totals of 83 rotifer species were collected, belonging to 30 genera and 12 families. The study showed that the annual average density and biomass of 3 sites in net-pen closing were lower than those in lake areas, density exhibited significant positive correlations with temperature. The CCA biplot of samples and environmental

  13. 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...

  14. Maine belowground marsh destruction from the European green crab documented by computer-aided tomography

    Science.gov (United States)

    Invasive European green crab (Carcinus maenus) populations have exploded with devastating losses to Maine’s intertidal resources including soft-shell clams, eelgrass beds, and salt marshes. This project quantified the green crab abundance in three different marsh locations ...

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. Barents Sea King Crab (Paralithodes camtschatica). The transplantation experiments were successfull

    OpenAIRE

    Kuzmin, Sergey; Olsen, Steinar

    1994-01-01

    As a result of the USSR tranplantation experiments, a viable, self-reproducing poulation of king crab, (Paralithodes camtschatica), is now well established in the Barents Sea. Commercial fishing for king crab is prohibited in both Russia and Norway, but these crabs are frequently taken as bycatches in coastal fisheries. Mature crabs are most numerous in the Varangerfjord area where experimental trap fishing by the two institutes have yielded catch rates comparable to those of r...

  1. 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

  2. DMPD: A Toll-like receptor in horseshoe crabs. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15199958 A Toll-like receptor in horseshoe crabs. Inamori K, Ariki S, Kawabata S. I...mmunol Rev. 2004 Apr;198:106-15. (.png) (.svg) (.html) (.csml) Show A Toll-like receptor in horseshoe crabs.... PubmedID 15199958 Title A Toll-like receptor in horseshoe crabs. Authors Inamori K, Ariki S, Kawabata S. Pu

  3. Simulating cryptic movements of a mangrove crab : Recovery phenomena after small scale fishery

    NARCIS (Netherlands)

    Piou, C.; Berger, U.; Hildenbrandt, H.; Grimm, V.; Diele, K.; D'Lima, C.

    2007-01-01

    The semi-terrestrial burrowing crab Ucides cordatus is an important ecological component and economic resource of Brazilian mangrove forests. The crab population of the Caete peninsula (the location of our study site) has been exploited for the last 40 years. Recovery of fished areas by crabs from n

  4. Things Chinese.

    Science.gov (United States)

    Law, Yip Wang

    Presented in this booklet are brief descriptions of items and activities that are symbolic of Chinese culture. Some of the items and activities described include a traditional Chinese child's outfit, dolls, sandalwood fans, writing and printing materials and techniques, toys and crafts, a Chinese abacus, and eating utensils. Several recipes for…

  5. 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...

  6. Radio emission physics in the Crab pulsar

    Science.gov (United States)

    Eilek, Jean A.; Hankins, Timothy H.

    2016-06-01

    > 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 -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 time scales, we know the emission zones are patchy and dynamic. It is tempting to invoke unsteady pair creation in high-altitude gaps as the 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 its dynamic spectrum. The most promising models are based on analogies with solar zebra bands, but they require unusual plasma structures which are not part of our standard picture of the magnetosphere. We argue that radio observations can reveal much about the upper magnetosphere, but work is required before the models can address all of the data.

  7. ELEMENT DISTRIBUTIONS IN THE CRAB NEBULA

    International Nuclear Information System (INIS)

    Images of the Crab Nebula have been obtained through custom interference filters that transmit emission from the expanding supernova remnant in He II λ4686, Hβ, He I λ5876, [O I] λλ6300, 6364, [N II] λλ6548, 6583, [S II] λλ6716, 6731, [S III] λ9069, and [C I] λλ9823, 9850. We present both raw and flux-calibrated emission-line images. Arrays of 19,440 photoionization models, with extensive input abundance ranges, were matched pixel by pixel to the calibrated data in order to derive corresponding element abundance or mass-fraction distributions for helium, carbon, nitrogen, oxygen, and sulfur. These maps show distinctive structure, and they illustrate regions of gas in which various stages of nucleosynthesis have apparently occurred, including the CNO cycle, helium burning, carbon burning, and oxygen burning. It is hoped that the calibrated observations and chemical abundance distribution maps will be useful for developing a better understanding of the precursor star evolution and the supernova explosive process.

  8. 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...

  9. 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...

  10. 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....

  11. 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...

  12. 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...

  13. 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...

  14. 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.

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

    International Nuclear Information System (INIS)

    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. (review article)

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Estimating the Fair Insurance Premium for Dungeness Crab Yields in the Western U.S. Coast

    OpenAIRE

    Liu, Chia-Lan; Richardson, James W.; Leatham, David J.

    2011-01-01

    The Dungeness is a popular food and the most commercially important crab in the western states in the U.S. Like all agricultural production, the crab fisherman face yield risks and must manage these risks. In addition to weather risk, crab fisherman may experience low yields if the crabs are over fished in previous years. Farmers for many traditional agricultural crops can purchase crop insurance to insure against low yields. However, crab fishermen at this time do not have this option. The p...

  2. 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.

  3. Associational resistance protects mangrove leaves from crab herbivory

    Science.gov (United States)

    Erickson, Amy A.; Bell, Susan S.; Dawes, Clinton J.

    2012-05-01

    While associational defenses have been well documented in many plant and algal ecosystems, this study is the first to document associational resistance in mangroves. Mangrove tree crab (Aratus pisonii) density and herbivory on three life-stages of the red mangrove (Rhizophora mangle) were documented in pure red versus mixed-species and predominantly non-red mangrove stands containing black (Avicennia germinans) and white (Laguncularia racemosa) mangroves in 1999-2000 in Tampa Bay, Florida. This study first established that R. mangle is the focal species in the context of associational resistance because it is damaged more than either of the other mangrove species. Next, it was hypothesized that crab density and leaf damage on R. mangle would be lower when in mixed-species and predominantly non-red versus red mangrove stands. A non-significant trend suggested that crab density varies among stands, and crab damage on R. mangle leaves was significantly lower in mixed-species and non-red stands. Mechanisms to explain associational resistance were examined. Positive Pearson correlations between the percent of adult R. mangle in a stand and both crab density and R. mangle leaf damage provided support for the resource concentration hypothesis. Limited support was found for the attractant-decoy hypothesis because the total amount of damaged leaves of all mangrove species combined typically differed among stands, suggesting that crabs were not shifting to alternative mangrove species to offset reduced availability of R. mangle leaves. Finally, while R. mangle seedlings were shorter in non-red stands compared to others, intra-specific differences in R. mangle leaf chemistry and sclerophylly among stands failed to explain associational patterns. These combined results argue for the need for additional experiments to elucidate mechanisms responsible for defensive plant associations in mangrove ecosystems and to determine whether such associations could be of use in mangrove

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. Mating Success of Female Dungeness Crabs (Cancer magister) in Oregon Coastal Waters

    DEFF Research Database (Denmark)

    Dunn, Paul; Shanks, Alan

    2012-01-01

    The Dungeness crab is an important commercial and sports fishing species in Oregon. The fishery is regulated by sex, size, and season. This study examined whether female crabs are mating despite the removal of almost all legal-size male crabs each year. Of particular concern is whether large...... females are finding large enough mates. Females were collected from three Oregon fishing ports, dissected, and checked for evidence of mating. Captured male and female crabs were also measured to estimate population size distributions. The majority of female crabs examined (69%) mated in the collection...... year, and when combined with crabs that carried sperm from previous mating encounters (females store sperm), the percent of females that would have produced viable eggs was 83%. Crabs that definitely molted during the collection year showed higher mating success (95%). The largest females examined...

  10. 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.

  11. Two new potamid crabs, Yuexipotamon arcophallus new genus, new species and Minutomon shanweiense new genus, new species, (Crustacea: Decapoda: Brachyura: Potamidae) from southern China.

    Science.gov (United States)

    Huang, Chao; Mao, Si Ying

    2014-02-12

    Two new Chinese genera and species of freshwater crabs, Yuexipotamon arcophallus, new genus, new species, and Minutomon shanweiense, new genus, new species, are described from Zhaoqing City and Shanwei City, respectively. The former is superficially closest to Huananpotamon Dai & Ng, 1994, while the latter resembles Sinopotamon Bott, 1967, and Mediapotamon Dai, 1995. The two new genera, however, possess distinctive combinations of carapace, third maxilliped, male thoracic sternal and first gonopodal characters that easily distinguish them from other genera. Notes on the general biology of the two new species are also given.

  12. 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.

  13. 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.

  14. 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...

  15. 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…

  16. Classroom Applications Using Limulus Polyphemus--The American Horseshoe Crab.

    Science.gov (United States)

    Pearson, Frederick C., III; Weary, Marlys

    1981-01-01

    Provides examples of several classroom activities utilizing the American horseshoe crab (Limulus Polyphemus), including raising fertilized eggs, fertilizing eggs in vitro, and testing water samples. Includes background information on the natural history, life cycle, and breeding habits of this animal. (DS)

  17. Gamma radiation from the Crab and Vela pulsars

    Science.gov (United States)

    Kanbach, Gottfried

    1990-01-01

    The young pulsars in Crab and Vela were observed as very efficient emitters of high energy gamma radiation. While their radiation in the radio, optical, and x ray range was always known to differ considerably, the gamma ray emission on a superficial level appears quite similar: lightcurves with two narrow peaks, separated by 141 deg (Crab) and 153 deg (Vela) and photon energies in excess of 1 GeV with spectra that can be described by a power-law for Crab and a broken power-law for Vela. The detailed observations of these sources with the COS-B instrument, extending over nearly seven years, have revealed significant differences in the characteristics of the pulsars in the gamma-ray domain. Secular changes in the temporal (Crab) and spectral (Vela) properties above 50 MeV were found. These tantalizing signatures of the pulsar emission processes must now be explored in more detail and over a larger spectral range with the GRO (Gamma Ray Observatory) instruments in order to gain a deeper understanding of the physics of young neutron stars.

  18. 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

  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. 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.

  1. Behavioral evidence illuminating the visual abilities of the terrestrial Caribbean hermit crab Coenobita clypeatus.

    Science.gov (United States)

    Ping, Xiaoge; Lee, Ji Sun; Garlick, Dennis; Jiang, Zhigang; Blaisdell, Aaron P

    2015-09-01

    Hermit crabs hide into shells when confronted with potential dangers, including images presented on a monitor. We do not know, however, what hermit crabs can see and how they perceive different objects. We examined the hiding response of the Caribbean hermit crab (Coenobita clypeatus) to various stimuli presented on a monitor in seven experiments to explore whether crabs could discriminate different properties of a threatening digital image, including color, brightness, contrast, shape and orientation. We found crabs responded differently to expanding circles presented in wavelengths of light corresponding to what humans see as red, blue, and green. "Blue" stimuli elicited the strongest hiding response (Experiments 1, 2, & 7). "Blue" was also more effective than a gray stimulus of similar brightness (Experiment 3). Hermit crabs were sensitive to the amount of contrast between a stimulus and its background rather than absolute brightness of the stimulus (Experiment 4). Moreover, we did not find evidence that crabs could discriminate orientation (Experiment 6), and mixed evidence that they could discriminate stimulus shape (Experiments 5 & 7). These results suggest that the Caribbean hermit crab is sensitive to color features, but not spatial features, of a threatening object presented on a computer screen. This is the first study to use the hiding response of the hermit crab to examine its visual ability, and demonstrates that the hiding response provides a useful behavioral approach with which to study learning and discrimination in the hermit crab. PMID:26051192

  2. Distribution and shell selection by two hermit crabs in different habitats on Egyptian Red Sea Coast

    Science.gov (United States)

    El-Kareem Ismail, Tarek Gad

    2010-05-01

    The present work aims to assess the spatial distribution, analyze shell utilization, shell fitness and determine the effect of coexistence of two hermit crabs Calcinus latens and Clibanarius signatus on used shell resources in various habitats on the Red Sea Coast. Also, to determine the choice of shells and investigate the shell species preference of C. latens and C. signatus in the laboratory. The hermit crabs C. latens and C. signatus were found to occupy shells of 39 gastropod species. The most commonly occupied gastropod shells are those belonging to genera Strombus, Nerita, Cerithium and Planaxis. The results showed that crab individuals utilized mainly the shell with elongate aperture. Laboratory experiments showed that two crab species preferred shells of Strombus followed by Cerithium and Nerita when offered shells of nearly similar size (optimal). Crab individuals showed a significant preference for optimal sized shells when given suboptimal shells as an alternative choice. Also, the hermit crabs avoid damaged shells when given a choice of optimal sized damaged shell and optimal sized intact one. In addition, two hermit crab species chose shells of smaller than optimal size when given a choice of damaged optimal sized shells and smaller intact ones. On the other hand, field observations showed that most crab individuals lived in adequate sized shells. The present data conclude that shell selection by hermit crabs C. latens and C. signatus depends mostly on shell internal volume, shell quality and shell aperture size than other factors, because they provide a maximum protection for hermit crabs.

  3. 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.

  4. 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

    2012-07-01

    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 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.

  5. Chinese Cooking.

    Science.gov (United States)

    Kane, Tony

    This unit, intended for secondary level students, is a general introduction to Chinese cooking. It is meant to inform students about the origins of Chinese cooking styles in their various regional manifestations, and it can be used to discuss how and why different cultures develop different styles of cooking. The first part of the unit, adapted…

  6. 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

  7. 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...

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

    Science.gov (United States)

    Ens, B. J.; Klaassen, M.; Zwarts, L.

    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 predators. A study in an intertidal area along the coast of Mauritania showed that small crabs always stayed in the vicinity of their burrow, but large crabs wandered in large flocks (also referred to as droves) to feed on sea-grass beds downshore. Transplanting downshore feeding substrate to the burrowing zone of the small crabs proved that they too preferred to feed on it. Since small crabs can be preyed upon by more species of birds, this suggests that the decision not to leave the burrowing zone might be related to the risk of being fed upon by birds. We calculated predation risk from measurements on the density and feeding activity of the crabs, as well as the feeding density, the intake rate and the size selection of the avian predators. Per hour on the surface, crabs in a flock were more at risk than crabs feeding near their burrow. Thus, though flocking crabs may have benefited from 'swamping the predator' by emerging in maximum numbers during some tides only, this did not reduce their risk of predation below that of non-flocking crabs. Furthermore we found that irrespective of activity, large crabs suffered a higher mortality per tide from avian predators than small crabs. This suggests that large crabs could not sufficiently reduce their foraging time to compensate for the increased risk while foraging in a flock, even though they probably experienced better feeding conditions than small crabs staying near their burrow. The greater energy demands of large crabs were reflected in a greater surface area grazed. Thus, with increasing size a fiddler crab has to feed further away from its burrow and so may derive less protection from staying near to it. It seems that

  9. 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.

  10. 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. PMID:25173366

  11. Effect of food availability on the growth and thermal physiology of juvenile Dungeness crabs (Metacarcinus magister)

    OpenAIRE

    McLean, KM; Todgham, AE

    2015-01-01

    Juvenile Dungeness crabs spend ~1 year in the San Francisco Estuary, where they undergo considerable growth before returning to the coastal ocean. Previous studies suggest that competition, food scarcity and avoidance of conspecifics may cause some juvenile Dungeness crabs in the San Francisco Estuary to become food limited. Food limitation may force these crabs to forage in higher temperature intertidal environments in the estuary, exposing them to stressful conditions in order to sustain gr...

  12. 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\

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. First Report of Two Diogenid Species of Hermit Crabs (Crustacea: Decapoda: Anomura from Korea

    Directory of Open Access Journals (Sweden)

    Jung, Jibom

    2015-04-01

    Full Text Available Two diogenid hermit crab species, Dardanus lagopodes and Diogenes deflectomanus, are newly reported from Korea. Dardanus lagopodes is distinguished from the other species of genus Dardanus in Korea by having setae with cream-colored tips on the cephalothorax and the following characteristics: ocular peduncles somewhat longer than antennular peduncles, and the pereopod without a longitudinal sulcus and scute-like projections. Diogenes deflectomanus is similar to D. nitidimanus but can be distinguished by having the fixed finger of the left cheliped bent slightly downwardly and the following characteristics: slightly shorter ocular peduncle, elongated left cheliped with small granules on the surface, right cheliped without calcareous teeth on the cutting edge of the dactylus, and the minute spine of post-median margin of the telson is not well developed. The geographical distributions of these two species are extended by the present study. In particular, D. deflectomanus in the current study is the first report outside Chinese waters. Now, 20 species of the family Diogenidae are known in Korean waters.

  2. Chinese Confucianism

    OpenAIRE

    Macfarlane, Alan; Cullen, Christopher

    2004-01-01

    Confucianism has deeply influenced Chinese civilization. Christopher Cullen describes its effect on education, social structure and knowledge over the past centuries, against the backdrop of a Confucian building in Beijing.

  3. Feeding Behavior of a Crab According to Cheliped Number

    Science.gov (United States)

    de Oliveira, Diogo Nunes; Christofoletti, Ronaldo Adriano; Barreto, Rodrigo Egydio

    2015-01-01

    Cheliped loss through autotomy is a common reflexive response in decapod crustaceans. Cheliped loss has direct and indirect effects on feeding behavior which can affect population dynamics and the role of species in the community. In this study, we assessed the impact of autotomy (0, 1, or 2 cheliped loss) on feeding behavior in the crab Pachygrapsus transversus, an omnivorous and abundant species that inhabits subtropical intertidal rocky shores along the South Atlantic Ocean. Autotomy altered crab feeding patterns and foraging behavior; however, the time spent foraging on animal prey or algae was not affected. These results indicate a plasticity of feeding behavior in P. transversus, allowing them to maintain feeding when injured. PMID:26682546

  4. 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.

  5. M10.3.1: LHC crab cavity specifications completed

    CERN Document Server

    Ciapala, E

    2010-01-01

    • The starting point of Sub-task 1 is to determine the full LHC system requirements for the crab cavity system. This milestone concerns completion of basic specifications for the crab cavity system. This comprises the beam requirements, the cavity impedance constraints, the operating conditions and constraints, the layout and integration constraints in LHC and very importantly machine protection issues. The specifications of the cavity itself and its ancillaries follow from these system requirements and on the technology chosen for the cavity design. • The beam requirements result from the known parameters of the LHC upgrade lattice and the expected LHC beam parameters at ultimate bunch intensity. There are boundary conditions imposed by certain beam parameters such as the bunch length and intensity and by the machine layout, mainly the available beam pipe separations at the proposed cavity positions. Requirements on RF noise and stability are tight, to avoid emittance blow-up. Machine protection issues a...

  6. 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.

  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 dust and gas content of the Crab Nebula

    OpenAIRE

    Owen, P.; Barlow, M.

    2015-01-01

    We have constructed MOCASSIN photoionization plus dust radiative transfer models for the Crab Nebula core-collapse supernova (CCSN) remnant, using either smooth or clumped mass distributions, in order to determine the chemical composition and masses of the nebular gas and dust. We computed models for several different geometries suggested for the nebular matter distribution but found that the observed gas and dust spectra are relatively insensitive to these geometries, being determined mainly...

  9. 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.

  10. Crab biodiversity under different management schemes of mangrove ecosystems

    OpenAIRE

    M. Bandibas; V. Hilomen

    2016-01-01

    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 managemen...

  11. 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. 

  12. First Test Results of the 4-ROD Crab Cavity

    CERN Document Server

    Ambattu, P; Burt, G; Calaga, R; Capatina, O; Calatroni, S; Ciapala, E; Doherty, D; Ferreira, L; Jensen, E; Hall, B; Lingwood, C; Maesen, P; Mongelluzzo, A; Renaglia, T; Therasse, M

    2013-01-01

    The first compact prototype crab cavity with the 4rod geometry has undergone surface treatment and cold testing. Due to the complex geometry and unique fabrication procedure, RF validation of the field at beyond the nominal operating voltage at a sufficiently high Q0 is an important pre-requisite. Preliminary results of the first cold tests are presented along with cavity performance at different stages of the cavity processing is described.

  13. 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.

  14. The Radio Spectral Index of the Crab Nebula

    CERN Document Server

    Bietenholz, M F; Frail, D A; Perley, R A; Erickson, W C; Hajian, A R

    1997-01-01

    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 combined with data at 327 MHz, 1.5 GHz and 5 GHz. In contrast to previous claims, little spatial variation in the spectral index is seen. In particular, between 327 MHz and 5 GHz we see no evidence of spectral steepening near the edge of the nebula, the ``jet'' or the ionized filaments. The rms limits on any spectral index variations in these regions amount to no more than 0.01. We believe that earlier reports of large steepening were the result of correlator bias and image registration problems. An elongated feature was detected wisp-like structures seen closer to the center of the nebula. At 74 MHz, we see for the first time evidence of free-free absorption by the 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 pul...

  15. 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 ...

  16. 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...

  17. 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.

  18. 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...

  19. 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.

  20. 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...

  1. Effects of coral bleaching on the obligate coral-dwelling crab Trapezia cymodoce

    Science.gov (United States)

    Stella, J. S.; Munday, P. L.; Jones, G. P.

    2011-09-01

    Corals are an essential and threatened habitat for a diverse range of reef-associated animals. Episodes of coral bleaching are predicted to increase in frequency and intensity over coming decades, yet the effects of coral-host bleaching on the associated animal communities remain poorly understood. The present study investigated the effects of host-colony bleaching on the obligate coral-dwelling crab, Trapezia cymodoce, during a natural bleaching event in the lagoon of Lizard Island, Australia. Branching corals, which harbour the highest diversity of coral associates, comprised 13% of live coral cover at the study site, with 83% affected by bleaching. Crabs on healthy and bleached colonies of Pocillopora damicornis were monitored over a 5-week period to determine whether coral bleaching affected crab density and movement patterns. All coral colonies initially contained one breeding pair of crabs. There was a significant decline in crab density on bleached corals after 5 weeks, with many corals losing one or both crabs, yet all healthy colonies retained a mating pair. Fecundity of crabs collected from bleached and healthy colonies of P. damicornis was also compared. The size of egg clutches of crabs collected from bleached hosts was 40% smaller than those from healthy hosts, indicating a significant reduction in fecundity. A laboratory experiment on movement patterns found that host-colony bleaching also prompted crabs to emigrate in search of more suitable colonies. Emigrant crabs engaged in aggressive interactions with occupants of healthy hosts, with larger crabs always usurping occupants of a smaller size. Decreased densities and clutch sizes, along with increased competitive interactions, could potentially result in a population decline of these important coral associates with cascading effects on coral health.

  2. Acanthocephala Parasite (Profilicollis spp.) Loads in Correlation to Pacific Mole Crab (Emerita analoga) Size

    Science.gov (United States)

    Cheng, T.; Huang, S.; Galathe, M.; Jenkins, M.; Ramirez, A.; Crosby, L.; Barrera, J.; FitzHoward, S.

    2013-12-01

    Since 2002, San Francisco Bay students have been conducting marine ecosystem monitoring through a joint project with the Long-term Monitoring Program and Experiential Training for Students (LiMPETS), in conjunction with the Gulf of Farallones National Marine Sanctuary. Each year students collect population and demographic data on Pacific mole crabs (Emerita analoga), an indicator species that lives in the sandy beach habitat in temperate regions along the Pacific Ocean. Pacific mole crabs are filter feeding crustaceans that inhabit the intertidal swash zone and are known to be an intermediate host for parasitic ';spiny-headed' worms in the phylum Acanthocephala (Profilicollis spp.). Sampling takes place during their reproductive period, which occurs from spring to fall, and includes measuring total body length of the Pacific mole crabs and dissecting them to determine presence of Acanthocephalan parasites. We hypothesize that due to larger body mass, larger Pacific mole crabs will have a greater number of Acanthocephala parasites.We conducted several analyses using the LiMPETS long-term data. Specifically, we compared body length, crab gender, and parasite abundance from Pacific mole crabs sampled from four beaches located in the county and city of San Francisco. Our results indicated that larger Pacific mole crabs do not necessarily have more parasites, but are more likely to have at least one parasite, while female Pacific mole crabs carrying eggs, have more parasites than males or females without eggs. We also found that parasite loads per mole crab was highest in the spring. Further analysis will be conducted to determine factors affecting Pacific mole crab parasite loads. Studying Pacific mole crabs help evaluate the health of California's intertidal systems and how human activities, geologic changes, and climate changes all make huge impacts to the intertidal ecosystems.

  3. 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

  4. 75 FR 48298 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-08-10

    ... Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab Rationalization Program; Recordkeeping... removes the Crab Rationalization Program requirements for catcher/processors to weigh all offloaded crab... INFORMATION CONTACT: Patsy A. Bearden, 907-586-7228. SUPPLEMENTARY INFORMATION: NMFS manages the U.S....

  5. 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...

  6. 76 FR 36511 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3

    Science.gov (United States)

    2011-06-22

    ... United States; Atlantic Deep-Sea Red Crab; Amendment 3 AGENCY: National Marine Fisheries Service (NMFS... Fishery Management Council (Council) has submitted Amendment 3 to the Atlantic Deep-Sea Red Crab Fishery... envelope, ``Comments on Red Crab Amendment 3.'' Instructions: All comments received are part of the...

  7. 78 FR 17341 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-21

    ... regulations implementing the Crab Rationalization Program (CR Program) in 2005 (70 FR 10174, March 2, 2005... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program AGENCY: National... to the Fishery Management Plan for Bering Sea/Aleutian Islands King and Tanner Crabs (FMP)....

  8. 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

  9. On scattering of Giant Pulses from the Crab Pulsar: a Scattering Function

    CERN Document Server

    Ershov, Alexander A

    2007-01-01

    Simultaneous dual-frequency observations of giant pulses from the Crab pulsar were performed at the frequencies of 61 and 111 MHz. It is shown that scattering of giant pulses from the Crab pulsar occurs at thick, and not at thin screen.

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

    OpenAIRE

    Calaga, R.; 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

  11. Synopsis of biological data on the blue crab, Callinectes sapidus Rathbun

    OpenAIRE

    Millikin, Mark R.; Williams, Austin B.

    1984-01-01

    This synopsis reviews taxonomy, morphology, distribution, life history, commercial hard and soft shell crab fisheries, physiology, diseases, ecology, laboratory culture methodology, and influences of environmental pollutants on the blue crab, Callinecles sapidus. Over 300 selected, published reports up to and including 1982 are covered. (PDF file contains 45 pages.)

  12. 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.

  13. 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.

  14. 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.

  15. 50 CFR Table 3c to Part 680 - Crab Product Codes for Economic Data Reports

    Science.gov (United States)

    2010-10-01

    ... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 680, Table 3c Table 3c to Part 680—Crab Product Codes for Economic... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab Product Codes for Economic Data Reports 3c Table 3c to Part 680 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT,...

  16.  The diversity of horseshoe crabs - protecting an endangered resource

    DEFF Research Database (Denmark)

    Funch, Peter; Cong, Nguyen Van; Intanai, Itsara;

    of the horseshoe crabs saves thousands of human lives every year. An extract from their blood are used worldwide to determine whether medicine, blood donations, and medical supplies are infected by bacteria or contain toxins. Horseshoe crabs are also fished for human consumption in Asia, are heavily used as bait...

  17. 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...

  18. 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.

  19. 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. PMID:22189504

  20. 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.

  1. 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.

  2. 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...... of geographically-based intraspecific variation. An admixture analysis showed regional intraspecific differentiation for males and females of L. polyphemus and males of the Asian horseshoe crab Carcinoscorpius rotundicauda, but not for females of C. rotundicauda and another Asian horseshoe crab, Tachypleus gigas...

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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

  8. Chinese Dream

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The general managers of South Korean auto giants Hyundai and Kia have high hopes for the growing Chinese auto market. Both companies went through a painstaking period as the financial crisis first roared across the globe. Jin Shan-fa, General Manager of Hyundai Motor Group

  9. 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.

  10. 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.

  11. Effects of pesticides on crab cheliped regeneration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Costlow, J.D. Jr.

    1993-06-01

    The mud crab cheliped regeneration bioassay has proven to be a sensitive and reliable bioassay in studies of the potential sublethal effects of pesticides, including teratogenesis, spontaneous autotomy, and duration of the various stages of development. The assay has also been demonstated to be a useful indication of mortality associated with the impact of these chemicals of anthropogenic origin during the megalopal and early postlarval stages of development. Four pesticides were tested here using the cheliped regeneration bioassay technique. Although carbofuran is approximately 5--6 times more toxic than methomyl, both compounds yield very similar results in terms of sublethal effects.

  12. 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

  13. Chinese Geography through Chinese Cuisine

    Science.gov (United States)

    Lipman, Jonathan

    2010-01-01

    China has the world's largest population, now over 1.3 billion, but its land area (much of it high mountains or desert) is about the same as that of the United States, which has less than one-fourth as many people. So Chinese farmers have learned to use every inch of their fertile land intensively. Pressure on the land has required extremely…

  14. 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.

  15. Living on the edge: Distribution of Dungeness crab Cancer magister in a recently deglaciated fjord

    Science.gov (United States)

    Taggart, S.J.; Hooge, P.N.; Mondragon, J.; Hooge, E.R.; Andrews, A.G.

    2003-01-01

    Glacier Bay, Alaska, has supported a productive Dungeness crab fishery, although the area where the fishery occurred was small relative to the remainder of the Bay. We hypothesized that 1 or more abiotic limiting factors prevented crabs from surviving in the upper Bay. We tested this hypothesis by systematically sampling for relative abundance of Dungeness crabs from the mouth to the head of the Bay. We measured salinity, temperature and turbidity at each of the sampling sites and at permanent stations to characterize the habitat within and among years. We expected to find a completely truncated spatial distribution. Instead, we found that adult Dungeness crabs can survive in habitats heavily influenced by tidewater glaciers. There were significantly fewer crabs in the upper Bay and a sharp decrease in abundance around 40 km from the mouth of the Bay. The region of the Bay beyond 40 km from the mouth had a very low density of predominately adult male crabs. The narrow size frequency distribution and the lack of small crabs is consistent with poor survival in one of the pre-adult life stages in the upper Bay.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  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. COMPTEL $\\gamma$-ray study of the Crab nebula

    CERN Document Server

    Van der Meulen, R D; Bennett, K; Hermsen, W; Kuiper, L; Much, R P; Ryan, J; Schönfelder, V; Strong, A

    1997-01-01

    We report on a study of the gamma-ray continuum emission from the Crab supernova nebula and on a search for nuclear de-excitation gamma-ray lines. Crab is the brightest continuum source in the 1-10 MeV gamma-ray sky, and its continuum radiation is most likely of synchrotron origin. It is a likely source of cosmic rays through shock acceleration and thus a potential candidate for gamma-ray line emission from nuclear interactions. Five years of COMPTEL observations enable a fine spectral binning to investigate the behaviour of the 0.75-30 MeV emission in detail and to search for nuclear de-excitation lines on top of the continuum. The nebular spectrum shows a break at the edge of the COMPTEL energy range and connects well to the EGRET spectrum, probably reflecting electron energy losses in the synchrotron emission scenario. Such a smooth continuum model alone may not be sufficient to explain the observations. A weak bump in the spectrum at 1-2 MeV may be present. No significant evidence for distinct line emissi...

  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. 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.

  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. 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.

  8. Progress towards crab cavity solutions for the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Lancaster U.; Bellantoni, L.; /Fermilab; Beard, C.; Goudket, P.; /Cockcroft Inst. Accel. Sci. Tech.

    2006-06-01

    In order to achieve acceptable luminosity for ILC crossing angles greater than 2 mrad, RF deflection cavities must be used to rotate electron and position bunches leading up to the IP. A bunch that passes through a deflection cavity at a phase where the deflection averages to zero, receives a crab kick leading to a finite rotation at the IP. For a beam energy of 500 GeV and a crossing angle of 20 mrad the required crab kick is about 11.4 MV at 1.3 GHz and 3.8 MV at 3.9 GHz. Cavities are needed on both beams and are likely to be positioned about 12 m before the IP. Any RF phase error between the bunch and the cavity leads to a deflection of the bunch in addition to a rotation of the bunch. Any differential phase error between the cavities leads to differing deflections and consequential loss in luminosity. An updated analysis of system requirements and phase tolerances with respect to original calculations [1] is given. Issues on cavity and frequency choice are discussed.

  9. Analysis of wakefields in the ILC crab cavity

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Lancaster U.; Bellantoni, L.; /Fermilab; Beard, C.; Goudket, P.; /Cockcroft Inst. Accel. Sci. Tech.; Jones, R.; /Manchester U.

    2006-06-01

    The large crossing angle schemes of the ILC need a correction of bunch orientation at the interaction point (IP) in order to recover a luminosity loss of up to 80%. The orientation of bunches can be changed using a set of transverse deflecting cavities. The location of these crab cavities would be close to the final focus, and small deflections caused by wake fields in the cavities could cause misalignments of the bunches at the IP. Wake fields in the 3.9GHz deflecting cavities under development at FNAL have been analysed and their effects studied in view of use as the ILC crab cavity. Numerical simulations have been performed to determine the long-range wake potentials of up to quadrupole order modes in this cavity and their effect upon bunches passing through this cavity. Trapped modes within the CKM cavity have been investigated. Short-range wakes have also been a topic of study. The effect of the final focus quadrupole magnets on the deflection given to the bunch have also been calculated and used to calculate luminosity loss due to wake fields.

  10. Patterns of diversity, areas of endemism, and multiple glacial refuges for freshwater crabs of the genus Sinopotamon in China (Decapoda: Brachyura: Potamidae).

    Science.gov (United States)

    Fang, Fang; Sun, Hongying; Zhao, Qiang; Lin, Congtian; Sun, Yufang; Gao, Wei; Xu, Juanjuan; Zhou, Junying; Ge, Feng; Liu, Naifa

    2013-01-01

    Previous research has shown that the geographical distribution patterns of freshwater fishes and amphibians have been influenced by past climatic oscillations in China resulting from Pleistocene glacial activity. However, it remains unknown how these past changes have impacted the present-day distribution of Chinese freshwater crabs. This work describes the diversity and endemism of freshwater crabs belonging to Sinopotamon, a highly speciose genus endemic to China, and evaluates its distribution in terms of topography and past climatic fluctuations. Species diversity within Sinopotamon was found to be concentrated in an area from the northeastern edge of the Yunnan-Guizhou Plateau to the Jiangnan Hills, and three areas of endemism were identified. Multiple regression analysis between current climatic variables and Sinopotamon diversity suggested that regional annual precipitation, minimum temperature in the coldest month, and annual temperature range significantly influenced species diversity and may explain the diversity patterns of Sinopotamon. A comparison of ecological niche models (ENMs) between current conditions and the last glacial maximum (LGM) showed that suitable habitat for Sinopotamon in China severely contracted during the LGM. The coincidence of ENMs and the areas of endemism indicated that southeast of the Daba Mountains, and central and southeastern China, are potential Pleistocene refuges for Sinopotamon. The presence of multiple Pleistocene refuges within the range of this genus could further promote inter- and intraspecific differentiations, and may have led to high Sinopotamon species diversity, a high endemism rate and widespread distribution.

  11. Chinese Weddings

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    ACCORDING to the Marriage Law of the People’s Republic of China, marital kinship is established and protected by law when a couple registers at tile local marriage registration office. The newly-weds usually hold a wedding feast in celebration at home or in a restaurant. The big red Chinese character, "Double Happiness," would be pasted on walls at the ceremonial hall to

  12. 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.

  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. 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

  15. 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....

  16. Distribution of the fiddler crab (Uca minax) in relation to marsh plants within a Virginia estuary

    Science.gov (United States)

    Kerwin, J.A.

    1971-01-01

    The distribution and abundance of the red-jointed fiddler crab, Uca minax, was related to the distribution of marsh plants within a Virginia estuary. The crab was found in association with 15 species of marsh phanerogams, occurring with five plant species more than 20 percent of the time. These plants were Spartina alterniflora, Scirpus robustus, Distichlis spicata, Spartina patens, and Spartina cynosuroides. Densities ranged from 0-76 burrows per square meter, mean densities being 7.88 within the brackish-water marsh and 14.35 within the salt-water marsh. The crab was not obtained by sampling the freshwater marsh.

  17. 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.

  18. Chinese Culture and Leadership.

    Science.gov (United States)

    Wong, Kam-Cheung

    2001-01-01

    Describes essential characteristics of Chinese philosophical tradition; Discusses Western perspectives on value leadership in education, particularly moral leadership. Discuses moral leadership from a Chinese philosophical perspective, especially Confucianism. Draws implications for using Chinese cultural and philosophical traditions to develop…

  19. Chinese restaurant syndrome

    Science.gov (United States)

    Chinese restaurant syndrome is a set of symptoms that some people have after eating Chinese food. A food additive ... Chinese restaurant syndrome is most often diagnosed based on the symptoms. The health care provider may ask the following ...

  20. CHINESE JOURNAL OF CHEMISTRY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Chinese Journal of Chemistry is an international journal published in English by the Chinese Chemical Society with its editorial office hosted by Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.

  1. 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

  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 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. PMID:27114859

  4. 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

  5. Transcriptome profiling of testis during sexual maturation stages in Eriocheir sinensis using Illumina sequencing.

    Directory of Open Access Journals (Sweden)

    Lin He

    Full Text Available The testis is a highly specialized tissue that plays dual roles in ensuring fertility by producing spermatozoa and hormones. Spermatogenesis is a complex process, resulting in the production of mature sperm from primordial germ cells. Significant structural and biochemical changes take place in the seminiferous epithelium of the adult testis during spermatogenesis. The gene expression pattern of testis in Chinese mitten crab (Eriocheir sinensis has not been extensively studied, and limited genetic research has been performed on this species. The advent of high-throughput sequencing technologies enables the generation of genomic resources within a short period of time and at minimal cost. In the present study, we performed de novo transcriptome sequencing to produce a comprehensive transcript dataset for testis of E. sinensis. In two runs, we produced 25,698,778 sequencing reads corresponding with 2.31 Gb total nucleotides. These reads were assembled into 342,753 contigs or 141,861 scaffold sequences, which identified 96,311 unigenes. Based on similarity searches with known proteins, 39,995 unigenes were annotated based on having a Blast hit in the non-redundant database or ESTscan results with a cut-off E-value above 10(-5. This is the first report of a mitten crab transcriptome using high-throughput sequencing technology, and all these testes transcripts can help us understand the molecular mechanisms involved in spermatogenesis and testis maturation.

  6. 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...

  7. 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...

  8. 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...

  9. Effect of salinity on larval growth of horseshoe crab, Tachypleus gigas (Muller)

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Kotnala, S.; Mathew, R.

    of temperature and salinity on su r- vival and development of early life stages of the Florida stone crabs, Menippe mercenaria (Say). J. Exp. Mar. Biol. Ecol ., 1992, 157 , 115 ? 136. ACKNOWLEDGEMENTS. We thank Dr E. Desa, Director, National...

  10. 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...

  11. 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.H.

    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...

  12. 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...

  13. 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)...

  14. 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,...

  15. 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...

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. Long-term in vitro generation of amoebocytes from the Indian horseshoe crab Tachypleus gigas (Muller)

    Digital Repository Service at National Institute of Oceanography (India)

    Joshi, B.; Chatterji, A.; Bhonde, R.

    Amoebocyte is the single type of cell circulating in the horseshoe crab hemolymph, which plays a major role in the defense system of the animal. Granules present in these cells are sensitive to nanogram quantities of bacterial endotoxins, which form...

  1. 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...

  2. Postlarval changes in the external morphology of dactyl setae in the kelp crab, Pugettia producta (Randall)

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, K.A.

    1983-01-01

    Morphological changes, which include growth, encrustation, and abrasion, occur in the sensory setae and nonsensory denticles located on the dactyls of the walking legs during the postlarval development of the kelp crab, Pugettia producta (Randall). The growth of the denticles is isometric (slope approx.1), while the growth of the setae is negatively allometric (slope < 1), relative to the growth of the dactyls. The increase in the sizes of the setae, but not of the denticles, appears to slow before growth stops at maturation, when molting ceases. The most striking morphological changes in the setae occur after maturation. While the setae of all but recently molted juvenile crabs are heavily encrusted by epibionts, the dactyls of most mature crabs are clean, and both the setae and denticles are so abraded that only their bases remain. The consequences of these morphological changes are discussed in relation to the sensory capabilities of a long-lived, nonmolting majid crab.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. Responses of ghost crabs to habitat modification of urban sandy beaches.

    Science.gov (United States)

    Stelling-Wood, Talia P; Clark, Graeme F; Poore, Alistair G B

    2016-05-01

    Sandy beaches in highly urbanised areas are subject to a wide range of human impacts. Ghost crabs are a commonly used ecological indicator on sandy beaches, as they are key consumers in these systems and counting burrow openings allows for rapid assessment of population size. This study assessed the pressures of urbanisation on sandy beaches in the highly urbanised estuary of Sydney Harbour. Across 38 beaches, we examined which physical beach properties, management practices and human induced habitat modification best predicted ghost crab distributions. Of all variables measured, the frequency of mechanical beach cleaning was the most important predictor of crab abundance, with low burrow densities at the highest cleaning frequency and the highest densities at beaches cleaned at the intermediate frequency (≤3 times per week). These results indicate that ghost crab populations in Sydney Harbour are more robust to the impacts of urbanisation than previously thought. PMID:26970686

  13. Crab Orchard National Wildlife Refuge : Annual Water Management Plan : Fiscal Year 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Water Management Plan has been developed to meet the station objectives set forth in the Master Plan. The purpose of this...

  14. 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...

  15. 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...

  16. 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

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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.

  11. 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....

  12. 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...

  13. 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...

  14. 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...

  15. Crab Orchard National Wildlife Refuge : Annual narrative report: Calendar year 1988

    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 1988 calendar year. The report begins with a...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Use of plastic debris as shelter by an unidentified species of hermit crab from the Maldives

    OpenAIRE

    Barreiros, João P.; Luiz Jr., Omar J.

    2009-01-01

    An unidentified species of hermit crab from the Maldives was photographed using a plastic box as shelter instead of a natural shell. This could be a result of increased pollution and shell collection disrupting the natural processes in coral reefs.

  1. 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...

  2. 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...

  3. Preferential feeding by the crab Necora puber on differing sizes of the intertidal limpet Patella vulgata

    OpenAIRE

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

    2010-01-01

    The crab Necora puber L. is a common predator of limpets, the major grazer on rocky shores in Northern Europe. Information on interactions between crabs and their limpet prey is limited, extending mainly to limpet defensive and predator offensive tactics, while the importance of prey size on the outcome of such interactions remains largely unknown. Here, a laboratory approach was used to test for preference in feeding habits. Predation by N. puber with cheliped height 3 to 27 mm (carapace wid...

  4. Food sources for the mangrove tree crab aratus pisonii: a carbon isotopic study

    International Nuclear Information System (INIS)

    Muscle tissues from the mangrove tree crab Aratus pisonii was analysed for carbon isotopic composition, in order to trace its major food sources. Potential food sources: mangrove leaves epi phytic green algae, mangrove sediments and open water and mangrove suspended matter; were also analysed. The results show that A. pisonii is basically omnivorous, with major food sources from marine origin. However, mangrove carbon can contribute with 16% to 42% in the crab's diet. (author)

  5. Development of Alternative Crab Claw Processing Systems to Minimize Environmental Impact

    OpenAIRE

    Benning, Jennifer Lyn

    1997-01-01

    Development of Alternative Crab Claw Processing Systems to Minimize Environmental Impact by Jennifer Lyn Benning Chair: Dr. Gregory Boardman Environemental Engineering (ABSTRACT) In the recent years, environmental regulations enforced by federal,state, and local agencies have increasingly addressed water quality issues through progressively more stringent regulations. These regulations have raised concerns in the blue crab industry because processors are now subject to regulations u...

  6. 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.

  7. 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.

  8. Contaminant effects in shore crabs (Carcinus maenas) from Ria Formosa Lagoon.

    Science.gov (United States)

    Maria, V L; Santos, M A; Bebianno, M J

    2009-08-01

    Defence and damage biomarkers signals were studied in female and male shore crabs Carcinus maenas transplanted between two sites at Ria Formosa Lagoon (South of Portugal). The cross transplantation occurred during 6 days at a hypothetical reference site (Ramalhete), and a contaminated site (Olhão). DNA unwinding technique was used for DNA integrity measurement. General enzymatic antioxidant responses in gills and hepatopancreas (catalase and gills glutathione peroxidase activities increase) showed that cross transplanted crabs (female and male) are suffering from pro-oxidant challenges at the Olhão site. Gills and hepatopancreas glutathione-S-transferase were reduced in both gender crabs transplanted from Ramalhete to Olhão. Metallothioneins induction occurred in crabs transplanted from Ramalhete to Olhão (contaminated by metals and polycyclic aromatic hydrocarbons (PAHs)). However metallothionein differences were also observed towards gender and organ specificities. High gills lipid peroxidation exist in male crabs transplanted from Ramalhete to Olhão, while in females it was the opposite. In both gender crabs from the Olhão site, gills DNA integrity decreased compared to the Ramalhete feral crabs. Moreover, hepatopancreas DNA integrity decreased in male crabs transplanted from Olhão to Ramalhete site which may be related to the environmental conditions (lower contamination levels) revealing the difficulty of selection of reference sites in field studies. Data demonstrated that female and male C. maenas antioxidant defences and damage biomarkers were sensitive to the mixture of contaminants present in these sites as well as good indicators of general stress.

  9. Sympatric three-species infection by Sacculina parasites (Cirripedia: Rhizocephala: Sacculinidae) of an intertidal grapsoid crab

    DEFF Research Database (Denmark)

    Tsuchida, Kohei; Lützen, Jørgen; Nishida, Mutsumi

    2006-01-01

    Parasitization by sacculinids (Cirripedia: Rhizocephala: Sacculinidae) induces severe modifications in morphology, behavior, and reproduction of their host crabs. To understand the mechanisms involved, it is important to have comprehensive information on their association. However, such information...... of Sacculina, S. confragosa, S. imberbis, and S. yatsui, were found to parasitize a single host crab, Pachygrapsus crassipes, sympatrically in a restricted area. This is the first finding for three-on-one association in a single locality....

  10. Toxicity Assessment of the Xanthid Crab Demania cultripes from Cebu Island, Philippines

    OpenAIRE

    Manabu Asakawa; Gloria Gomez-Delan; Shintaro Tsuruda; Michitaka Shimomura; Yasuo Shida; Shigeto Taniyama; Mercy Barte-Quilantang; Jo Shindo

    2010-01-01

    Several cases of poisoning resulting in human fatalities and stemming from the ingestion of coral reef crabs have been reported from the Indo-Pacific region. We assessed the toxicity of the unidentified xanthid crab collected from the Camotes Sea off the eastern coast of Cebu Island, central Visayas region of Philippines from the food hygienic point of view. All seven specimens, which were identified with Demania cultripes, collected in 2006 were toxic to mice irrespective of the season of co...

  11. 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.

  12. 5th LHC Crab Cavity Workshop, LHC-CC11 Workshop Summary Report

    OpenAIRE

    G. Arduini; Calaga, R.; Ciapala, E.; Collier, P; Giovannozzi, M.; Jensen, E.; Koutchouk, J.P.; Mcintosh, P.; Metral, E.; Myers, S; Parma, V; Wenninger, J.; Zimmermann, F

    2012-01-01

    The 5th workshop on crab cavities for the LHC luminosity upgrade (LHC-CC11) was held from 14 to 15 November 2011 at CERN, Geneva, Switzerland. This report summarizes the contributions from the workshop and provides an overview of the present status of the crab crossing scheme considered for the LHC upgrade. The executive summary synthesizes the key conclusions from the advisory board session and lists the required next steps for R&D, testing and final implementation at the LHC.

  13. Chinese Calendar and Chinese Telegraphic Code.

    Science.gov (United States)

    Defense Language Inst., Monterey, CA.

    This manual contains: (1) Chinese calendars for the hundred years from 1881 to 1980; and (2) the Chinese telegraphic code. Each page in Part One presents the calendar for each year in both Chinese and English. There are 97 charts in Part Two representing the telegraphic code. (AMH)

  14. The crab pulsar at tera-electron-volts energies

    Energy Technology Data Exchange (ETDEWEB)

    Carreto Fidalgo, David [Universidad Complutense, Madrid (Spain); Galindo, Daniel; Zanin, Roberta [Universitat de Barcelona, ICC IEEC-UB, Barcelona (Spain); Ona Wilhelmi, Emma de [Institute of Space Sciences, Barcelona (Spain); Rodriguez Garcia, Jezabel [Max-Planck-Institut fuer Physik, Muenchen (Germany); Inst. de Astrofisica de Canarias, La Laguna Tenerife (Spain); Dazzi, Francesco [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: MAGIC-Collaboration

    2015-07-01

    MAGIC is a system of two 17 m-diameter Imaging Atmospheric Cherenkov Telescopes (IACTs) located at the Roque de los Muchachos observatory (ORM, 28.8 N, 17.8 W, 2200 m a.s.l.) on the Canary island of La Palma. This system has observed the most energetic ever detected pulsed gamma-ray from an astrophysical source, 2 Tera-electron-Volt emission from the Crab pulsar. Such measurements shed light on the particle acceleration mechanism of pulsars, pointing to Inverse Compton scattering of IR-X-ray photons at a distance bigger than 25 stellar radii from the neutron star. These are highly relevant results, since they challenge all the existing theoretical models as none of them can reproduce all the constrains that this observation has imposed.

  15. Regulation of blood pressure in the land crab Cardisoma guanhumi.

    Science.gov (United States)

    Wilkens, J L; Young, R E

    2006-01-01

    We examined the cardiovascular responses to acute and chronic changes in blood volume (BV) in the land crab Cardisoma guanhumi. Acute reduction in BV caused an increase in activity in the dorsoventral muscles (DVMs) and to a lesser extent in the epimeral attractor muscles (EAMs). Contraction of the DVMs and EAMs will decrease the volume of the dorsal sinus and the thorax as a whole, respectively. BV reduction also caused bradycardia with frequent periods of cardiac arrest. There was a small drop in hemolymph pressure. BV expansion had the reciprocal effect on DVM and EAM activity but had no effect on heart rate (fH). After the cardioregulatory nerves were cut, acute hypovolemia had no effect on fH but still caused a moderate increase in DVM activity. After dehydration-induced BV reduction, DVM activity increased, whereas hemolymph pressure, fH, and EAM activity were maintained close to control levels.

  16. Spectroscopy and 3D imaging of the Crab nebula

    CERN Document Server

    Cadez, A; Vidrih, S

    2004-01-01

    Spectroscopy of the Crab nebula along different slit directions reveals the 3 dimensional structure of the optical nebula. On the basis of the linear radial expansion result first discovered by Trimble (1968), we make a 3D model of the optical emission. Results from a limited number of slit directions suggest that optical lines originate from a complicated array of wisps that are located in a rather thin shell, pierced by a jet. The jet is certainly not prominent in optical emission lines, but the direction of the piercing is consistent with the direction of the X-ray and radio jet. The shell's effective radius is ~ 79 seconds of arc, its thickness about a third of the radius and it is moving out with an average velocity 1160 km/s.

  17. Gamma-ray flares from the Crab nebula

    International Nuclear Information System (INIS)

    A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (1015 electron volts) electrons in a region smaller than 1.4 * 10-2 parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory. (authors)

  18. Evolution of the Magnetic Field Structure of the Crab Pulsar

    CERN Document Server

    Lyne, Andrew; Weltevrede, Patrick; Jordan, Christine; Stappers, Ben; Bassa, Cees; Kramer, Michael

    2013-01-01

    Pulsars are highly-magnetised rotating neutron stars and are well-known for the stability of their signature pulse shapes, allowing high-precision studies of their rotation. However, during the past 22 years, the radio pulse profile of the Crab pulsar has shown a steady increase in the separation of the main pulse and interpulse components at 0.62$^{\\rm o}\\pm$0.03$^{\\rm o}$ per century. There are also secular changes in the relative strengths of several components of the profile. The changing component separation indicates that the axis of the dipolar magnetic field, embedded in the neutron star, is moving towards the stellar equator. This evolution of the magnetic field could explain why the pulsar does not spin down as expected from simple braking by a rotating dipolar magnetic field.

  19. Dairy Wastewater Treatment Using Low Molecular Weight Crab Shell Chitosan

    Science.gov (United States)

    Geetha Devi, M.; Dumaran, Joefel Jessica; Feroz, S.

    2012-08-01

    The investigation of possible use of low molecular weight crab shell chitosan (MW 20 kDa) in the treatment of dairy waste water was studied. Various experiments have been carried out using batch adsorption technique to study the effects of the process variables, which include contact time, stirring speed, pH and adsorbent dosage. Treated effluent characteristics at optimum condition showed that chitosan can be effectively used as adsorbent in the treatment of dairy wastewater. The optimum conditions for this study were at 150 mg/l of chitosan, pH 5 and 50 min of mixing time with 50 rpm of mixing speed. Chitosan showed the highest performance under these conditions with 79 % COD, 93 % turbidity and 73 % TSS reduction. The result showed that chitosan is an effective coagulant, which can reduce the level of COD, TSS and turbidity in dairy industry wastewater.

  20. Crab Waist collision scheme: a novel approach for particle colliders

    CERN Document Server

    Zobov, Mikhail

    2016-01-01

    A new concept of nonlinear focusing of colliding bunches, called Crab Waist (CW)collision scheme, has been proposed at LNF INFN. It has been successfully tested at the Italian lepton collider DAFNE in operational conditions providing luminosity for two different experimental detectors, SIDDHARTA and KLOE-2. Considering a high efficiency of the scheme for increasing collision luminosity and its relative simplicity for implementation several new collider projects have been proposed and are under development at present. These are the SuperKEKB B-factory ready to start commissioning in 2016 in Japan, the SuperC-Tau factory proposed in Novosibirsk and entered in the short list of Russian mega-science projects, the new 100-km electron-positron Future Circular Collider (FCC-ee) under design study at CERN and some others. In this paper we describe the CW collision scheme, discuss its advantages and report principal results achieved at the electron-positron Phi-factory DAFNE.

  1. Modeling Gamma-ray Flares in the Crab Nebula

    Science.gov (United States)

    Yuan, Yajie; Blandford, R. D.; Simeon, P.

    2013-04-01

    The gamma-ray emission from the Crab Nebula shows variations on a wide range of time scales, with the most dramatic events being the flares observed by Fermi and AGILE: the flux can increase by a factor of ~10 within ~10 hours; the spectrum is characterized by a peak energy ~300 MeV, while no variation in other wavebands was detected. These variations present a great challenge to particle acceleration mechanisms. We consider two possible explanations of these flares. Firstly, we consider emission from a moving relativistic shock terminating the pulsar wind. Secondly, we treat the pulsar and its wind as a current generator and suppose that the current filaments into individual pinches that can undergo radial collapse and become strongly dissipative when the electric field becomes as strong as the magnetic field and Larmor radius of the highest energy particles becomes comparable with the radius. The application of these models to pulsar wind nebulae and relativistic jets will be outlined.

  2. Unraveling the Geometry of the Crab Nebula's "Inner Ring"

    CERN Document Server

    Weisskopf, Martin C; Kolodziejczak, Jeffery J; O'Dell, Stephen L; Tennant, Allyn F

    2011-01-01

    Chandra images of the Crab Nebula resolve the detailed structure of its "inner ring", possibly a termination shock where pulsar-accelerated relativistic particles begin to emit X radiation. Analysis of these images finds that the center of the ellipse-presumably a circular ring in projection-lies about 0.9" (10 light-days at 2 kpc) from the pulsar's image, at a position angle of about 300{\\deg} (East of North). This analysis also measures properties of the ellipse: The position angle of the semi-major axis is about 210{\\deg} (East of North); the aspect ratio, 0.49. In a simple-albeit, not unique-de-projection of the observed geometry, a circular ring is centered on the axis of symmetry of the pulsar wind nebula. This ring is not equatorial but rather lies near +4.5{\\deg} latitude in pulsar-centered coordinates. Alternative geometries are briefly discussed.

  3. Renegotiating property rights in the Florida golden crab fishery

    Directory of Open Access Journals (Sweden)

    Scott Crosson

    2013-08-01

    Full Text Available The golden crab (Chaceon fenneri supports a small, economically healthy fishery in south Florida. Crabbers in the fishery have successfully protected themselves against larger outside fishing interests in the past, and management has been stable for over fifteen years.  Why, then, did a portion of the fleet propose shifting to individual transferable quotas (ITQs?  Our findings suggest that proponents sought ITQ management because they believed it would further limit the ability of other crabbers to enter the fishery and act as a mechanism to legally preserve the informal and formal property rights that they have previously negotiated among themselves. Opponents believed that a shift to an ITQ regime would destroy those same property rights.  We explore the implications of these findings to a broader understanding of property rights and natural resource management institutions, noting that the currently existing system closely resembles a territorial use rights fishery (TURF.

  4. 800MHz Crab Cavity Conceptual Design For the LHC Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Liling; Li, Zenghai; Ng, Cho-Kuen; Seryi, Andrei; /SLAC

    2009-05-26

    In this paper, we present an 800 MHz crab cavity conceptual design for the LHC upgrade. The cell shape is optimized for lower maximum peak surface fields as well as higher transverse R/Q. A compact coax-to-coax coupler scheme is proposed to damp the LOM/SOM modes. A two-stub antenna with a notch filter is used as the HOM coupler to damp the HOM modes in the horizontal plane and rejects the operating mode at 800MHz. Multipacting (MP) simulations show that there are strong MP particles at the disks. Adding grooves along the short axis without changing the operating mode's RF characteristics can suppress the MP activities. Possible input coupler configurations are discussed.

  5. The Influence of Diet Composition on Fitness of the Blue Crab, Callinectes sapidus.

    Science.gov (United States)

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-01-01

    The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the economically and ecologically important blue crab, Callinectes sapidus, to approximate the effects of a dietary shift from primarily animal to plant tissue, a phenomenon commonly documented in crabs. Crabs whose diet consisted exclusively of animal tissue had markedly lower mortality and consumed substantially more food than crabs whose diet consisted exclusively of seaweed. The quantity of food consumed had a significant positive influence on reproductive effort and long-term energy stores. Additionally, seaweed diets produced a three-fold decrease in hepatopancreas lipid content and a simultaneous two-fold increase in crab aggression when compared to an animal diet. Our results reveal that the consumption of animal tissue substantially enhanced C. sapidus fitness, and suggest that a dietary shift to plant tissue may reduce crab population growth by decreasing fecundity as well as increasing mortality. This study has implications for C. sapidus fisheries.

  6. The importance of color in mate choice of the blue crab Callinectes sapidus.

    Science.gov (United States)

    Baldwin, Jamie; Johnsen, Sönke

    2009-11-01

    Visual displays often play a large role in animal communication, particularly in sexual interactions. The blue crab Callinectes sapidus is both colorful and highly visually responsive, yet almost all studies of their courtship have focused on chemical cues. In the blue crab's underwater environment, however, visual cues may function more rapidly and over a longer distance than chemical cues. Given that blue crabs are aggressive and cannibalistic, visual cues may therefore allow blue crabs to quickly evaluate potential mates from safer distances. In the present study we show that courtship and mate choice behavior in C. sapidus can be stimulated by visual cues alone. Further, we show that males have a preference for females with red claw dactyls. In binary choice experiments, males displayed more often to photographs of females with red claws than to those with white claws or to those with black claws that were isoluminant to the red ones. This strongly suggests that male blue crabs made their choices based on the hue of the red claws, further suggesting that blue crabs are capable of color vision and use color in mate choice.

  7. The effects of magnetic field, age, and intrinsic luminosity on Crab-like pulsar wind nebulae

    CERN Document Server

    Torres, D F; Wilhelmi, E de Oña; Cillis, A

    2013-01-01

    We investigate the time-dependent behavior of Crab-like pulsar wind nebulae (PWNe) generating a set of models using 4 different initial spin-down luminosities ($L_0 =\\{1,0.1,0.01,0.001\\} \\times L_{0, {\\rm Crab}}$), 8 values of magnetic fraction ($\\eta =$ 0.001, 0.01, 0.03, 0.1, 0.5, 0.9, 0.99, and 0.999, i.e., from fully particle dominated to fully magnetically dominated nebulae), and 3 distinctive ages: 940, 3000, and 9000 years. We find that the self-synchrotron Compton (SSC) contribution is irrelevant for $L_{SD}$=0.1, 1, and 10% of the Crab power, disregarding the age and the magnetic fraction. SSC only becomes relevant for highly energetic ($\\sim 70%$ of the Crab), particle dominated nebulae at low ages (of less than a few kyr), located in a FIR background with relatively low energy density. Since no pulsar other than Crab is known to have these features, these results clarify why the Crab Nebula, and only it, is SSC dominated. No young PWN would be detectable at TeV energies if the pulsar's spin-down po...

  8. Multispecies modeling for adaptive management of horseshoe crabs and red knots in the Delaware Bay

    Science.gov (United States)

    McGowan, Conor P.; Smith, David; Sweka, John A.; Martin, Julien; Nichols, James D.; Wong, Richard; Lyons, James E.; Niles, Lawrence J.; Kalasz, Kevin; Brust, Jeffrey; Klopfer, Michelle; Spear, Braddock

    2011-01-01

    Adaptive management requires that predictive models be explicit and transparent to improve decisions by comparing management actions, directing further research and monitoring, and facilitating learning. The rufa subspecies of red knots (Calidris canutus rufa), which has recently exhibited steep population declines, relies on horseshoe crab (Limulus polyphemus) eggs as their primary food source during stopover in Delaware Bay during spring migration. We present a model with two different parameterizations for use in the adaptive management of horseshoe crab harvests in the Delaware Bay that links red knot mass gain, annual survival, and fecundity to horseshoe crab dynamics. The models reflect prevailing hypotheses regarding ecological links between these two species. When reported crab harvest from 1998 to 2008 was applied, projections corresponded to the observed red knot population abundances depending on strengths of the demographic relationship between these species. We compared different simulated horseshoe crab harvest strategies to evaluate whether, given this model, horseshoe crab harvest management can affect red knot conservation and found that restricting harvest can benefit red knot populations. Our model is the first to explicitly and quantitatively link these two species and will be used within an adaptive management framework to manage the Delaware Bay system and learn more about the specific nature of the linkage between the two species.

  9. American alligator digestion rate of blue crabs and its implications for stomach contents analysis

    Science.gov (United States)

    Nifong, James C.; Rosenblatt, Adam E.; Johnson, Nathan A.; Barichivich, William; Silliman, Brian; Heithaus, Michael R.

    2012-01-01

    Stomach contents analysis (SCA) provides a snap-shot observation of a consumer's diet. Interpretation of SCA data can be complicated by many factors, including variation in gastric residence times and digestion rates among prey taxa. Although some SCA methods are reported to efficiently remove all stomach contents, the effectiveness of these techniques has rarely been tested for large irregular shaped prey with hard exoskeletons. We used a controlled feeding trial to estimate gastric residency time and decomposition rate of a large crustacean prey item, the Blue Crab (Callinectes sapidus), which is consumed by American Alligators (Alligator mississippiensis), an abundant apex predator in coastal habitats of the southeastern United States. The decomposition rate of C. sapidus in the stomachs of A. mississippiensis followed a predictable pattern, and some crab pieces remained in stomachs for at least 14 days. We also found that certain portions of C. sapidus were prone to becoming caught within the stomach or esophagus, meaning not all crab parts are consistently recovered using gastric lavage techniques. However, because the state of decomposition of crabs was predictable, it is possible to estimate time since consumption for crabs recovered from wild alligators. This information, coupled with a detailed understanding of crab distributions and alligator movement tactics could help elucidate patterns of cross-ecosystem foraging by the American Alligator in coastal habitats

  10. Reproductive behavior in horseshoe crabs: Does density matter?

    Directory of Open Access Journals (Sweden)

    Jennifer H. MATTEI, Mark A. BEEKEY, Adam RUDMAN, Alyssa WORONIK

    2010-10-01

    Full Text Available While the four species of horseshoe crabs share many common reproductive traits with respect to their reproductive systems, they do differ with respect to their mating behavior (monogamy vs. polygynandry. Past research has attributed these differences to a number of factors including: spawning densities, operational sex ratios (OSR’s, male condition (or age, environmental and/or genetic factors, or a combination thereof. Mating behaviors in the three Asian horseshoe crab species (Tachypleus gigas, T. tridentatus, and Carcinoscorpius rotundicauda with low spawning densities and 1:1 operational sex ratios are typically monogamous. In Limulus polyphemus, mating behavior is more variable ranging from monogamy to polygynandry. Here we provide evidence, through a long term behavioral study, that variation in mating behavior is influenced by population density in L. polyphemus. Our study population on two beaches in Connecticut (Long Island Sound have a spawning density 400 times less than that found in Delaware Bay (0.002 females/m2 vs. 0.8 females/m2 but similar operational sex ratios. Between 90%–95% of all spawning females in CT were paired with only one male, thus exhibiting monogamous behavior. In contrast, between 30 and 60% of spawning females in Delaware Bay have more than one mate and produce clutches of eggs with multiple paternities. Male condition played no role in mating behavior in CT populations. We also observed that on average 18% of the females on the spawning beaches are single. These results suggest that population density is an important condition that determines mating behavior. Also, low population density may lead to decreased mate finding ability and lost opportunities for spawning [Current Zoology 56 (5: 634–642, 2010].

  11. Developmental ecology of the American horseshoe crab Limulus polyphemus

    Directory of Open Access Journals (Sweden)

    Mark L. BOTTON, Richard A. TANKERSLEY, Robert E. LOVELAND

    2010-10-01

    Full Text Available During spawning events, horseshoe crab eggs are released from the female’s oviducts, and fertilized by one or more males. Eggs are shaped by the female into discrete clutches deposited in nests at depths of 10-20 cm on intertidal estuarine beaches. Distinguishing between fresh eggs and the early developmental stages is obfuscated by the large amount of dense, opaque yolk. The first unambiguous confirmation of development is the formation of the rudimentary prosomatic appendages at the “limb bud” stage. Several days thereafter, the outer chorion is shed and the developing embryo expands and undergoes a series of molts within the clear inner egg membrane. The trilobite (first instar stage thus attained may remain within the beach sediments for several more weeks, until hatching is facilitated by environmental factors such as hydration, agitation, and osmotic shock that accompany the infiltration of seawater into the nests. Trilobites exhibit endogenous circatidal swimming rhythms that are entrained by mechanical agitation, suggesting that peaks in larval swimming are timed to coincide with periods of high water and the inundation of the nests. Larval swimming is limited and does not appear to result in long-distance dispersal. The limited dispersal of the larvae has important implications for the population dynamics of relatively isolated populations. The rate of larval development is highly plastic and is influenced by temperature, salinity, dissolved oxygen, and the presence of pollutants. The broad environmental tolerances of horseshoe crab embryos and larvae are important in understanding their current geographic distribution and their evolutionary persistence [Current Zoology 56 (5: 550–562, 2010].

  12. Capture-based mud crab (Scylla serrata) aquaculture and artisanal fishery in East Africa: practical and ecological perspectives.

    OpenAIRE

    Mirera, David Oersted

    2013-01-01

    Mud crab Scylla serrata is a crustacean that spends most of its life cycle in the mangrove environment throughout its range. Fishery and aquaculture of this crab are significant economic activities in coastal areas in the tropics and sub-tropics because of the meat quality and nutritional value. However there is a significant shortage of information on the ecology, fishery and aquaculture of these crabs in sub-Saharan Africa. This impacts the development of a sustainable aquaculture and fishe...

  13. Chinese letterkunde. Een inleiding

    NARCIS (Netherlands)

    Idema, Wilt; Haft, Lloyd

    2005-01-01

    De Chinese cultuur mag zich verheugen in een groeiende belangstelling. Chinese films bereiken in Nederland een steeds omvangrijker publiek en ook de moderne Chinese literatuur, die sinds de jaren tachtig een grote bloei doormaakt, wordt door veel liefhebbers op de voet gevolgd. Chinese Letterkunde b

  14. Dungeness Crab Dredging Entrainment Studies in the Lower Columbia River, 2002 – 2004: Loss Projections, Salinity Model, and Scenario Analysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-01-01

    Dungeness crab studies conducted in 2002 for the Portland District of the U.S. Army Corps of Engineers (Corps) constituted a major step forward in quantifying crab entrainment through statistical projections of adult equivalent loss (AEL) and loss to the fishery (LF) from proposed construction and maintenance dredging in the Columbia River navigation channel (Pearson et al. 2002, 2003). These studies also examined the influence of bottom salinity on crab abundance and entrainment rates. Additional sampling was conducted in 2004 to tighten loss projections, further develop the crab salinity model, and apply the model to assess correlations of entrainment rates and projected losses with seasonal salinity changes.

  15. Observations on the Behavior of the Dark Crab Callinectes rathbunae Contreras Parasitized with the Rhizocephalan Loxothylacus texanus Boschma

    Directory of Open Access Journals (Sweden)

    A. Moran

    2006-01-01

    Full Text Available One hundred and fourty nine crabs of the species Callinectes rathbunae Contreras parasitized with the rhizocephalan Loxothylacus texanus Boschma were captured. The average shell width was 8.48 cm. Three types of externa were registered in the hosts: virgin, immature and mature externa; their number varied from one to four, being more common the crabs with one externa. The behavior of parasitized crabs was registered during six months. The most aggressive crabs were those that presented virgin externa (n = 82, while the less aggressive ones were those who presented three to four mature externa (n = 3. The crabs with virgin and immature externa conserved the capacity of burying themselves, while the organisms with mature externa lost that capacity. The animals with mature externa passed most of the time grooming and oxygenating the externa they carried. The crabs with mature externa presented bigger voracity that the crabs with immature externa. It can be concluded that the level of aggressiveness of the parasitized crabs is related with the degree of development of the externa, the degree of aggressiveness of the parasitized crabs is not related with the sex and mature externa represent a great metabolic load for their hosts.

  16. Management of Chinese restaurant

    OpenAIRE

    Cui , Longbo

    2009-01-01

    With Chinese economy developing rapidly, the Chinese restaurant is under the spotlight, but the management of Chinese restaurant is weak at the moment, especially on the service management, which is an important part of service management in the Chinese restaurant. On the other hand, the managers of Chinese restaurant should pay more attention on the service management for instance brand, service innovation. Service management is core and essential concept for every service company recently, ...

  17. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental...

  18. Snow crab allergy and asthma among Greenlandic workers – a pilot study

    Directory of Open Access Journals (Sweden)

    Jakob Hjort Bønløkke

    2012-08-01

    Full Text Available Objectives. To study snow crab sensitization, occupational allergy and asthma in the snow crab industry in Greenland, as high rates have been found in Canada, but no reports have emerged from the same industry in Greenland. Study design. Pilot survey. Methods. Twenty workers (19 of Inuit and 1 of other origin in a snow crab (Chionoecetes opilio and Atlantic shrimp (Pandalus borealis processing plant in Greenland were assessed with skin prick tests (SPTs with common aeroallergens and specific allergens from snow crab and shrimp extracts, spirometry, blood sampling for total IgE and specific IgE determination. Eighteen workers contributed a questionnaire-based medical interview. Results. Positive skin prick test reactions were common to snow crab (40% and shrimp (20%. Specific IgE to snow crab were positive in 4 workers (21%. Two workers had elevated total IgE levels. Symptoms suggestive of asthma were common (45%. Work-related symptoms of skin rash, rhinitis, and/or conjunctivitis were reported by 50%, and symptoms from the lower airways by 39%. Combining history of work-related symptoms with results from specific SPTs and/or specific IgE determination suggested that 11 and 22% of workers suffered from probable and possible occupational asthma, respectively, whereas 22% had possible occupational dermatitis or rhinitis. Conclusions. Greenlander Inuit do not appear to be protected against sensitization to snow crab or shrimp when occupationally exposed to these. This pilot study suggests that occupational allergy and asthma may be as common a problem in Greenlandic workers as in Canadian.

  19. Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat.

    Science.gov (United States)

    Gittman, Rachel K; Keller, Danielle A

    2013-12-01

    Ecologists have long been interested in identifying and testing factors that drive top-down or bottom-up regulation of communities. Most studies have focused on factors that directly exert top-down (e.g., grazing) or bottom-up (e.g., nutrient availability) control on primary production. For example, recent studies in salt marshes have demonstrated that fronts of Littoraria irrorata periwinkles can overgraze Spartina alterniflora and convert marsh to mudflat. The importance of indirect, bottom-up effects, particularly facilitation, in enhancing primary production has also recently been explored. Previous field studies separately revealed that fiddler crabs, which burrow to depths of more than 30 cm, can oxygenate marsh sediments and redistribute nutrients, thereby relieving the stress of anoxia and enhancing S. alterniflora growth. However, to our knowledge, no studies to date have explored how nontrophic facilitators can mediate top-down effects (i.e., grazing) on primary-producer biomass. We conducted a field study testing whether fiddler crabs can facilitate S. alterniflora growth sufficiently to mitigate overgrazing by periwinkles and thus sustain S. alterniflora marsh. As inferred from contrasts to experimental plots lacking periwinkles and fiddler crabs, periwinkles alone exerted top-down control of total aboveground biomass and net growth of S. alterniflora. When fiddler crabs were included, they counteracted the effects of periwinkles on net S. alterniflora growth. Sediment oxygen levels were greater and S. alterniflora belowground biomass was lower where fiddler crabs were present, implying that fiddler crab burrowing enhanced S. alterniflora growth. Consequently, in the stressful interior S. alterniflora marsh, where subsurface soil anoxia is widespread, fiddler crab facilitation can mitigate top-down control by periwinkles and can limit and possibly prevent loss of biogenically structured marsh habitat and its ecosystem services.

  20. CRAB NEBULA: FIVE-YEAR OBSERVATION WITH ARGO-YBJ

    Energy Technology Data Exchange (ETDEWEB)

    Bartoli, B.; Catalanotti, S.; D' Ettorre Piazzoli, B.; Di Girolamo, T. [Dipartimento di Fisica dell' Università di Napoli " Federico II," Complesso Universitario di Monte Sant' Angelo, via Cinthia, I-80126 Napoli (Italy); Bernardini, P.; D' Amone, A.; De Mitri, I. [Dipartimento Matematica e Fisica " Ennio De Giorgi," Università del Salento, via per Arnesano, I-73100 Lecce (Italy); Bi, X. J.; Cao, Z.; Chen, S. Z. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, 100049 Beijing (China); Branchini, P.; Budano, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Camarri, P. [Dipartimento di Fisica dell' Università di Roma " Tor Vergata," via della Ricerca Scientifica 1, I-00133 Roma (Italy); Cardarelli, R.; Di Sciascio, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Chen, T. L.; Danzengluobu [Tibet University, 850000 Lhasa, Xizang (China); Creti, P. [Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, via per Arnesano, I-73100 Lecce (Italy); Cui, S. W. [Hebei Normal University, Shijiazhuang 050016 Hebei (China); Dai, B. Z., E-mail: vernetto@to.infn.it [Yunnan University, 2 North Cuihu Rd., 650091 Kunming, Yunnan (China); Collaboration: ARGO-YBJ Collaboration; and others

    2015-01-10

    The ARGO-YBJ air shower detector monitored the Crab Nebula gamma-ray emission from 2007 November to 2013 February. The integrated signal, consisting of ∼3.3 × 10{sup 5} events, reached the statistical significance of 21.1 standard deviations. The obtained energy spectrum in the energy range 0.3-20 TeV can be described by a power law function dN/dE = I {sub 0} (E/2 TeV){sup –α}, with a flux normalization I {sub 0} = (5.2 ± 0.2) × 10{sup –12} photons cm{sup –2} s{sup –1} TeV{sup –1} and α = 2.63 ± 0.05, corresponding to an integrated flux above 1 TeV of 1.97 × 10{sup –11} photons cm{sup –2} s{sup –1}. The systematic error is estimated to be less than 30% for the flux normalization and 0.06 for the spectral index. Assuming a power law spectrum with an exponential cutoff dN/dE = I {sub 0} (E/2 TeV){sup –α} exp (–E/E {sub cut}), the lower limit of the cutoff energy E {sub cut} is 12 TeV, at 90% confidence level. Our extended data set allows the study of the TeV emission over long timescales. Over five years, the light curve of the Crab Nebula in 200-day bins is compatible with a steady emission with a probability of 7.3 × 10{sup –2}. A correlated analysis with Fermi-LAT data over ∼4.5 yr using the light curves of the two experiments gives a Pearson correlation coefficient r = 0.56 ± 0.22. Concerning flux variations on timescales of days, a ''blind'' search for flares with a duration of 1-15 days gives no excess with a significance higher than four standard deviations. The average rate measured by ARGO-YBJ during the three most powerful flares detected by Fermi-LAT is 205 ± 91 photons day{sup –1}, consistent with the average value of 137 ± 10 day{sup –1}.

  1. 50 CFR Table 35 to Part 679 - Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Apportionment of Crab PSC and Halibut PSC... 35 to Part 679—Apportionment of Crab PSC and Halibut PSC Between the Amendment 80 and BSAI Trawl Limited Access Sectors Fishery Year Halibut PSC limit in the BSAI Zone 1 Red king crab PSC limit . . ....

  2. 50 CFR Table 41 to Part 679 - BSAI Crab PSC Sideboard Limits for AFA Catcher/Processors and AFA Catcher Vessels

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false BSAI Crab PSC Sideboard Limits for AFA...) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Table 41 Table 41 to Part 679—BSAI Crab PSC... following areas . . . The AFA catcher/processor crab PSC sideboard limit is equal to the...

  3. Gender and snow crab occupational asthma in Newfoundland and Labrador, Canada

    International Nuclear Information System (INIS)

    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 (P<0.001). Worker health assessments carried out with 215 processing workers (187 current/28 former; 120 female/95 male) found that female participants were more likely to be diagnosed as almost certain/highly probable snow crab OA and allergy (P=0.001) and to be sensitized to snow crab (P=0.01) than male participants. Work histories from the health assessments were used to classify processing jobs 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 (p<0.001 and P=0.017 for these plants). A gender 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

  4. Continuous sorption of copper and cobalt by crab shell particles in a packed column.

    Science.gov (United States)

    Vijayaraghavan, K; Thilakavathi, M; Palanivelu, K; Velan, M

    2005-03-01

    The ability of crab shell to remove copper and cobalt from aqueous solutions was examined in an up-flow packed column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 25 cm, metal uptake capacity of crab shell for copper and cobalt was 52.07 and 20.47 mg g(-1) respectively. In addition, the results obtained at different flow rates indicated that an increase in flow rate decreased the sorption performance of the crab shell. The Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated for copper and cobalt sorption. The column regeneration studies were carried out for five sorption-desorption cycles. Loss of sorption performance was observed as the cycles progressed, indicated by a shortened breakthrough time and a broadened mass transfer zone. However, crab shell maintained a good metal sorption capacity for all the five cycles. The elutant used for the regeneration of the crab shell, 0.01 M EDTA at pH 3.5 adjusted using HCI, exhibited elution efficiencies greater than 98%. PMID:15881023

  5. CRAB3: Establishing a new generation of services for distributed analysis at CMS

    Science.gov (United States)

    Cinquilli, M.; Spiga, D.; Grandi, C.; Hernàndez, J. M.; Konstantinov, P.; Mascheroni, M.; Riahi, H.; Vaandering, E.

    2012-12-01

    In CMS Computing the highest priorities for analysis tools are the improvement of the end users’ ability to produce and publish reliable samples and analysis results as well as a transition to a sustainable development and operations model. To achieve these goals CMS decided to incorporate analysis processing into the same framework as data and simulation processing. This strategy foresees that all workload tools (TierO, Tier1, production, analysis) share a common core with long term maintainability as well as the standardization of the operator interfaces. The re-engineered analysis workload manager, called CRAB3, makes use of newer technologies, such as RESTFul based web services and NoSQL Databases, aiming to increase the scalability and reliability of the system. As opposed to CRAB2, 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 serving the user tasks. The new architecture of CRAB substantially changes the deployment model and operations activities. In this paper we present the implementation of CRAB3, emphasizing how the new architecture improves the workflow automation and simplifies maintainability. In particular, we will highlight the impact of the new design on daily operations.

  6. When a Standard Candle Flickers: Hard X-ray Variations in the Crab Nebula

    Science.gov (United States)

    Wilson-Hodge, Colleen; Cherry, Michael L.; Case, Gary L.; Baumgartner, Wayne H.; Beklen, Elif; Bhat, Narayana P.; Briggs, Michael Stephen; Buehler, Rolf; Camero-Arranz, Ascension; Connaughton, Valerie; Diehl, Roland; Finger, Mark H.; Gehrels, Neil; Greiner, Jochen; Harrison, Fiona; Hays, Elizabeth A.; Jahoda, Keith; Jenke, Peter; Kippen, R. Marc; Kouveliotou, Chryssa; Krimm, Hans A.; Kuulkers, Erik; Madsen, Kristin; Markwardt, Craig; Meegan, Charles A.; Natalucci, Lorenzo; Paciesas, William Simon; Preece, Robert D.; Rodi, James; Shaposhnikov, Nikolai; Skinner, Gerald K.; Swartz, Douglas A.; von Kienlin, Andreas; Zhang, Xiao-Ling

    2015-01-01

    In the first two years of science operations of the Fermi Gamma-ray Burst Monitor (GBM), August 2008 to August 2010, a ~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 ~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. At higher energies, above 50 keV, the Crab flux appears to be slowly recovering to its 2008 levels. I will present updated light curves in multiple energy bands for the Crab nebula, including recent data from Fermi GBM, Swift/BAT, INTEGRAL, MAXI, and NuSTAR and a 16-year long light curve from RXTE/PCA. We will compare these variations to higher energies as well, e.g. Fermi LAT.

  7. [Applicability of PCR methods for detection of shrimp and crab in processed food].

    Science.gov (United States)

    Taguchi, Hiromu; Nagatomi, Yasuaki; Kikuchi, Ryo; Hirao, Takashi

    2014-01-01

    According to Japanese food allergen labeling regulations, an ELISA screening test is used for detection of crustacean proteins in food and a shrimp/crab-PCR confirmation test is used to confirm a positive ELISA screening test and to exclude false positives. Forty-six kinds of processed foods labeled as containing shrimp/crab were subjected to ELISA screening test and PCR confirmation test and the usefulness of the shrimp/crab-PCR was evaluated. Twenty-seven of the 46 samples contained total crustacean protein levels of 10 ppm or more in the ELISA screening test. All of the samples were positive in the shrimp/crab-PCR confirmation test. The results of the confirmation test were consistent with the declaration in the list of ingredients and with the results of the ELISA screening test. The shrimp/crab-PCR confirmation test was demonstrated to be applicable to various kinds of foods, including powder, extract, seasoning paste, prepared frozen food, snack food, retort food and canned food.

  8. Effects of horseshoe crab harvest in delaware bay on red knots: Are harvest restrictions working?

    Science.gov (United States)

    Niles, L.J.; Bart, J.; Sitters, H.P.; Dey, A.D.; Clark, K.E.; Atkinson, P.W.; Baker, A.J.; Bennett, K.A.; Kalasz, K.S.; Clark, N.A.; Clark, J.; Gillings, S.; Gates, A.S.; Gonzalez, P.M.; Hernandez, D.E.; Minton, C.D.T.; Morrison, R.I.G.; Porter, R.R.; Ross, R.K.; Veitch, C.R.

    2009-01-01

    Each May, red knots (Calidris canutus rufa) congregate in Delaware Bay during their northward migration to feed on horseshoe crab eggs (Limulus polyphemus) and refuel for breeding in the Arctic. During the 1990s, the Delaware Bay harvest of horseshoe crabs for bait increased 10-fold, leading to a more than 90% decline in the availability of their eggs for knots. The proportion of knots achieving weights of more than 180 grams by 26-28 May, their main departure period, dropped from 0.6-0.8 to 0.14-0.4 over 1997-2007. During the same period, the red knot population stopping in Delaware Bay declined by more than 75%, in part because the annual survival rate of adult knots wintering in Tierra del Fuego declined. Despite restrictions, the 2007 horseshoe crab harvest was still greater than the 1990 harvest, and no recovery of knots was detectable. We propose an adaptive management strategy with recovery goals and annual monitoring that, if adopted, will both allow red knot and horseshoe crab populations to recover and permit a sustainable harvest of horseshoe crabs.

  9. Rotational evolution of the Crab pulsar in the wind braking model

    CERN Document Server

    Kou, F F

    2015-01-01

    The pulsar wind model is updated by considering the effect of particle density and pulsar death. It can describe both the short term and long term rotational evolution of pulsars consistently. It is applied to model the rotational evolution of the Crab pulsar. The pulsar is spun down by a combination of magnetic dipole radiation and particle wind. The parameters of the Crab pulsar, including magnetic field, inclination angle, and particle density are calculated. The particle density in acceleration region is about 10^3 times the Goldreich-Julian charge density. The lower braking index between glitches is due to a larger particle density. This may be glitch induced magnetospheric activities in normal pulsars. Evolution of braking index and the Crab pulsar in P-Pdot diagram are calculated. The Crab pulsar will evolve from magnetic dipole radiation dominated case towards particle wind dominated case. Considering the effect of pulsar "death", the Crab pulsar (and other normal pulsars) will not evolve to the clust...

  10. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    Science.gov (United States)

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents.

  11. Use of Hyperspectral Imagery to Assess Cryptic Color Matching in Sargassum Associated Crabs.

    Science.gov (United States)

    Russell, Brandon J; Dierssen, Heidi M

    2015-01-01

    Mats of the pelagic macroalgae Sargassum represent a complex environment for the study of marine camouflage at the air-sea interface. Endemic organisms have convergently evolved similar colors and patterns, but quantitative assessments of camouflage strategies are lacking. Here, spectral camouflage of two crab species (Portunus sayi and Planes minutus) was assessed using hyperspectral imagery (HSI). Crabs matched Sargassum reflectance across blue and green wavelengths (400-550 nm) and diverged at longer wavelengths. Maximum discrepancy was observed in the far-red (i.e., 675 nm) where Chlorophyll a absorption occurred in Sargassum and not the crabs. In a quantum catch color model, both crabs showed effective color matching against blue/green sensitive dichromat fish, but were still discernible to tetrachromat bird predators that have visual sensitivity to far red wavelengths. The two species showed opposing trends in background matching with relation to body size. Variation in model parameters revealed that discrimination of crab and background was impacted by distance from the predator, and the ratio of cone cell types for bird predators. This is one of the first studies to detail background color matching in this unique, challenging ecosystem at the air-sea interface. PMID:26352667

  12. Simulation of Crab Waist Collisions in DAΦNE with KLOE-2 Interaction Region

    Energy Technology Data Exchange (ETDEWEB)

    Zobov, M. [Frascati; Drago, A. [Frascati; Gallo, A. [Frascati; Milardi, C. [Frascati; Shatilov, D. [Novosibirsk, IYF; Valishev, A. [Fermilab

    2015-06-24

    After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentially achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e⁻ ring working point was implemented and resulted in a significant performance increase.

  13. Simulation of Crab Waist Collisions In DA$\\Phi$NE With KLOE-2 Interaction Region

    Energy Technology Data Exchange (ETDEWEB)

    Zobov, M. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF); Drago, A. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF); Gallo, A. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF); Milardi, C. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF); Shatilov, D. [Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP); Valishev, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-06-24

    After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentially achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e- ring working point was implemented and resulted in a significant performance increase.

  14. Discovery of an opportunistic starfish pathogen, Orchitophrya stellarum, in captive blue crabs, Callinectes sapidus.

    Science.gov (United States)

    Small, H J; Miller, T L; Coffey, A H; Delaney, K L; Schott, E; Shields, J D

    2013-10-01

    Histophagous scuticociliate infections were discovered in blue crabs, Callinectes sapidus, held in research facilities at the Virginia Institute of Marine Science. Ciliates were observed infecting every tissue examined including the gills, heart, muscle, hepatopancreas, and epidermis. Hemolymph smears and histological tissue sections indicated a morphological similarity to Mesanophrys chesapeakensis, the only recorded histophagous ciliate infecting blue crabs. However, subsequent analysis of the ribosomal ITS region (ITS1-5.8S-ITS2) of the ciliate indicated the parasite was Orchitophrya stellarum, a parasitic ciliate previously reported infecting sea stars from Europe, Australia, and North America. A simple Polymerase Chain Reaction (PCR-RFLP) assay was developed to detect and differentiate between O. stellarum and M. chesapeakensis. Its application confirmed the presence of O. stellarum infecting blue crabs held in an additional research facility in Maryland. For growth studies, cultures of O. stellarum grew optimally on 10% blue crab serum in crustacean saline held at 10-20°C. A field survey of blue crabs collected during the winters of 2011-2012 and sea stars (Asterias forbesi) during the winter of 2010 from the Chesapeake Bay and eastern shore of Virginia did not identify additional infected individuals.

  15. First complete mitochondrial genome of primitive crab Homologenus malayensis (Decapoda: Brachyura: Podotremata: Homolidae).

    Science.gov (United States)

    Hui, Min; Liu, Yuan; Cui, Zhaoxia

    2016-01-01

    The taxonomy and phylogeny of brachyuran crabs, and particularly of the Podotremata, have been the subjects of controversy due to their morphological diversity and complexity. The first complete mitochondrial genome (mitogenome) sequence of primitive crab Homologenus malayensis has been determined. The mitogenome is 15,793 bp in length, with A + T content 71.7%. The gene content and order are consistent with those in typical brachyuran crabs. A putative control region of 883 bp is identified due to its position (between srRNA and tRNA(Ile)) and AT richness (75.5%). Notably, the control region in H. malayensis contains nine identical specific repeat units of 42 bp and 11 identical repeat units of 2 bp with a total length of 400 bp, which is different from other crabs. These results are expected to provide useful information on both genomics and the future phylogenetic study of primitive crabs.

  16. Population structure of the burrowing crab Neohelice granulata (Brachyura, Varunidae in a southwestern Atlantic salt marsh

    Directory of Open Access Journals (Sweden)

    Sabrina Angeletti

    2015-07-01

    Full Text Available Neohelice granulata inhabits estuarine and protected coastal areas in temperate regions and is the most dominant decapod crustacean in the Bahía Blanca Estuary, Argentina. The population structure was studied during a year in a SW Atlantic salt marsh located in the Bahía Blanca Estuary. Crabs were sampled monthly from August 2010 to July 2011. The maximum observed density was 30 crabs m-2 in February and 70 burrows m-2 in May. The maximum carapace width (CW was 32 and 27.5 mm in males and females respectively. Medium size crabs were between 16 and 20 mm CW. Significantly smaller sized crabs were observed at the lower intertidal regions (P < 0.05. The sex ratio was favorable for males and was significantly different from the expected 1:1 (P < 0.05. The recruitment of unsexed juveniles crabs (CW <6.5 mm was observed throughout the year and the presence of ovigerous females from October to February indicated seasonal reproduction. The average size of ovigerous females was CW = 20.8 mm and the smallest ovigerous female measured was 16 mm CW. For the first time, the population structure of the most important macro-invertebrate is analyzed in the Bahía Blanca Estuary. This study may help to make decisions in the area, where anthropic action is progressing day by day.

  17. Infection of juvenile edible crabs, Cancer pagurus by a haplosporidian-like parasite.

    Science.gov (United States)

    Thrupp, Tara J; Lynch, Sharon A; Wootton, Emma C; Malham, Shelagh K; Vogan, Claire L; Culloty, Sarah C; Rowley, Andrew F

    2013-09-01

    This study aimed to examine the pathobiology of a haplosporidian-like infection in juvenile (pre-recruit) edible crabs (Cancer pagurus) from two locations in South West Wales, UK. Infected crabs showed no external symptoms of the disease but dissection revealed an infected and hypertrophic antennal gland. Histological examination showed extensive parasitisation of the antennal gland overlying the hepatopancreas. Heavily infected crabs also showed the presence of parasites with morphological similarities to Haplosporidia in the labyrinth of the antennal gland and in the gills. The spread of the infection from the antennal gland to the gills suggests that these parasites are released into the haemolymph. Attempts to characterise the haplosporidian-like organism using several primers previously shown to amplify members of the phylum Haplosporidia failed. The prevalence of infection in juvenile edible crabs varied throughout the sampling period of November 2011 to July 2012 with the lowest level of ca. 15% in November peaking at 70% in March. This parasite may represent a threat to the sustainability of edible crab fisheries in this region if the damage observed in the antennal gland and gills results in host mortality. The identification of these parasites as members of the phylum Haplosporidia based on morphology alone must be seen as tentative in the absence of sequence data.

  18. Diversity and habitat preference of brachyuran crabs in Gulf of Kutch, Gujarat, India

    Directory of Open Access Journals (Sweden)

    J. N. Trivedi

    2012-03-01

    Full Text Available The biodiversity of Gulf of Kutch is studied well with special reference to scleretinia and mollusca but the brachyuran crab taxa are rather neglected. Gulf of Kutch is very rich in floral and faunal diversity and comprises different types of communities and habitats like very unique coral reefs, mangroves, sandy shores, rocky shores and mudflats. Brachyuran crabs are the most diverse group among marine fauna having 5000 species world wide. Some studies on the intertidal fauna, including brachyuran crabs, have been carried out in Gulf of Kutch but the findings were not sufficient to draw out taxonomic diversity. Present work on Gulf of Kutch is an initiative to scan the entire coastal Gujarat and establish directory of brachyuran crab diversity. Since the Gulf habitat is diverse and distinct, eight different stations (16 sample sites were sampled. The selection of the sample site was done on the basis of habitat type which included mangrove mudflats, open mudflats and rocky shores. A total of 19 species belonging to 8 families and 15 genera were recorded. Open mud flats were most preferred by the crabs followed by the mangrove mud flats and rocky shore.

  19. Use of Hyperspectral Imagery to Assess Cryptic Color Matching in Sargassum Associated Crabs.

    Science.gov (United States)

    Russell, Brandon J; Dierssen, Heidi M

    2015-01-01

    Mats of the pelagic macroalgae Sargassum represent a complex environment for the study of marine camouflage at the air-sea interface. Endemic organisms have convergently evolved similar colors and patterns, but quantitative assessments of camouflage strategies are lacking. Here, spectral camouflage of two crab species (Portunus sayi and Planes minutus) was assessed using hyperspectral imagery (HSI). Crabs matched Sargassum reflectance across blue and green wavelengths (400-550 nm) and diverged at longer wavelengths. Maximum discrepancy was observed in the far-red (i.e., 675 nm) where Chlorophyll a absorption occurred in Sargassum and not the crabs. In a quantum catch color model, both crabs showed effective color matching against blue/green sensitive dichromat fish, but were still discernible to tetrachromat bird predators that have visual sensitivity to far red wavelengths. The two species showed opposing trends in background matching with relation to body size. Variation in model parameters revealed that discrimination of crab and background was impacted by distance from the predator, and the ratio of cone cell types for bird predators. This is one of the first studies to detail background color matching in this unique, challenging ecosystem at the air-sea interface.

  20. Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider

    CERN Document Server

    Sun, Y P; Barranco, J; Tomás, R; Weiler, T; Zimmermann, F; Calaga, R; Morita, A

    2009-01-01

    Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The long-range beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing a crossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The 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 use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit...